Even in these days, food poisoning due to tetrodotoxin (TTX) still occurs, but there are no clinical trials of methods to measure TTX concentration. In this study, we attempted to establish a new enzyme-linked immunosorbent assay (ELISA) system for assessing TTX concentration. First, we established six patterns of noncompetitive ELISA to generate calibration curves, and we determined the best two antibodies for measuring TTX concentration. Next, the novel assay system was used for fourteen simultaneous measurements of equivalent TTX concentrations (100 μg/mL) within different matrices (citrate buffer, urine, or serum). Using this ELISA system, we determined the concentration of TTX diluted in citrate buffer with high accuracy and precision. However, the TTX concentration in urine was low (37.36 μg/mL), whereas that in serum was high (249.86 μg/mL). To correct the effect of interfering components in each biological sample, we regenerated calibration curves using serial dilutions of the TTX standard prepared using urine or serum. Then, the TTX concentration in urine was increased (111.86 μg/mL), but that in serum remained high (162.92 μg/mL). Finally, deproteinization treatment increased the TTX concentration in serum (111.29 μg/mL) measured by this new ELISA system. Although this ELISA system still needs further improvement, for measuring the TTX concentration in biological samples, this method would be useful for laboratory medicine to some extent.

The appropriate storage of histopathological specimens is important for continuous patient care in various fields such as carcinoma genomic medicine. Usually, block surfaces after sectioning are thinly coated with paraffin for protection against damage and oxidation. However, some tissues are lost during cutting with repeated use of stored tissue blocks. In this study, we attempted to overcome this problem by using hydrosoluble paraffin. The specimens used were multiple control tissues and tissues from the tonsil and lung. In this investigation, we compared among specimens with hydrosoluble paraffin and conventional paraffin coating and without coating. Hydrosoluble paraffin was removed by washing with running water or immersion on an ice bath. The hydrosoluble paraffin protected tissues from cracking and oxidation. The time required to remove hydrosoluble paraffin was 5 min in running water and 30 min on an ice bath. HE-stained and immunostained specimens remained stable for six months. However, the attenuation of MIB-1 staining and decrease in DIN value occurred in tissue blocks stored for three years. The repeated use of tissue blocks induced tissue degeneration or water absorption, indicating the loss of the protective effect of hydrosoluble paraffin. Therefore, the use of a fresh reagent is important. Our novel method of covering tissue blocks using hydrosoluble paraffin is easy, and there is little tissue loss after a rapid surface cutting and repeated use of tissue blocks. In conclusion, the new tissue protection method is useful especially for very small specimens such as needle biopsy specimens.

Chagas disease (CD) is a chronic infectious disease caused by the intracellular parasite Trypanosoma cruzi and originally prevalent in Latin American countries. It was estimated that about 25% of patients with CD develop chronic complications decades after infection. In this study, we evaluated the usefulness of the following two serological test kits available in Japan for CD: ARCHITECT Chagas Reagent Kit (Abbott, Chicago, IL) and Trypanosoma Detect^TM Rapid Test Kit (InBios, Seattle, WA). A total of 192 serum samples were used in this study as follows: 20 from patients previously diagnosed as having CD in Japan, 72 from those previously diagnosed in Bolivia, and 100 from Japanese patients without CD in Saitama University Hospital. All patients were confirmed to have CD by ELISA and IFA in accordance with the previously reported protocol. Analysis using the ARCHITECT Chagas Reagent Kit demonstrated a 100% diagnostic concordance in all populations. The Trypanosoma Detect^TM Rapid Test Kit, an immunochromatography test (ICT) kit, showed 99.4% sensitivity and 100% specificity. In this study, an automated immunoassay and ICT kits, which are also available in Japan, demonstrated good clinical performance for detecting antibodies against T. cruzi. However, the potential for false-negative results of serologic tests, especially those using the rapid ICT test kits, remained. Further research using a wider variety of clinical serum samples will be required to determine the usefulness of these test kits in Japan.

In hospital practice, the use of the antigen quantitative test for the diagnosis of symptomatic patients suspected of having COVID-19 and screening for asymptomatic pathogen carriers must be considered separately. We examined the effectiveness of and the problems encountered with the use of the antigen quantitative test in two groups: symptomatic patients suspected of having COVID-19 and asymptomatic pathogen carriers. There were 277 symptomatic patients suspected of having COVID-19 and 1,781 asymptomatic patients who underwent both the RT-PCR test and SARS-CoV-2 antigen quantitative test on the same day from November 2020 to May 2021. A retrospective analysis was performed on a total of 2,058 samples. In the symptomatic patients suspected of having COVID-19, when the antigen level obtained was ≥ 0.36 pg/mL indicating positivity for SARS-CoV-2, the antigen quantitative test used for diagnosis showed a sensitivity of 95.9% and a specificity of 80.4%. In the asymptomatic patients, when the antigen level obtained was ≥ 0.83 pg/mL, the antigen quantitative test used for screening showed a sensitivity of 100% and a specificity of 99.5%. In this analysis, the antigen quantitative test was found to be extremely effective for screening for asymptomatic individuals. On the other hand, when the test is used for the purpose of diagnosing symptomatic patients, its sensitivity and specificity are slightly reduced. Therefore, it is necessary to fully understand its characteristics and make a comprehensive judgment based on a combination of clinical symptoms, diagnostic imaging, PCR tests, and antibody tests.

Objective: Mu-opioid receptor gene OPRM1 118A>G polymorphisms have been considered possible candidate factors for both opioid effects and psychophysical responses. In this study, we investigate the association between OPRM1 118A>G polymorphisms and personality traits. Method: After written informed consent was obtained from participants, OPRM1 118A>G gene polymorphisms were analyzed by polymerase chain reaction (PCR)—restriction fragment length polymorphism (RFLP), and personality was assessed using Neuroticism Extraversion Openness-Five Factor Inventory (NEO-FFI) and State-Trait Anxiety Inventory (STAI) in 236 Japanese university students. Statistical analyses were performed by the unpaired t-test and Welch’s t-test. Results: A significant relationship was found between OPRM1 118A>G polymorphisms and NEO-FFI and STAI scores: participants with the A allele exhibited a higher conscientiousness score (p = 0.024) and a lower neuroticism score (p = 0.065) in NEO-FFI, and a lower STAI score (p = 0.023) than those without the A allele. Conclusion: We conclude that OPRM1 may affect conscientiousness and neuroticism measured using NEO-FFI and trait anxiety measured using STAI.

Autoimmune hemolytic anemia (AIHA) is a disease in which red blood cells are damaged by autoantibodies that react with antigens on the red blood cell membrane causing hemolysis. The direct antiglobulin test (DAT) has become the gold standard for the diagnosis of AIHA, and if the result is positive, the diagnosis of AIHA is relatively easily established. However, some cases of AIHA show negative DAT results; therefore, diagnosis based on DAT results only is infeasible. Quantification of red blood cell-bound IgG (RBC-IgG) is useful in such cases. The RBC-IgG measurement has mainly been by the RIA method, but it is difficult to introduce it as a routine method owing to problems related to radioactivity. Considering this background, we studied a method of measuring RBC-IgG by flow cytometry and used the mean fluorescence intensity difference (MFID) as an indicator of RBC-IgG. For DAT-negative samples, we successfully set a reference range for MFID and confirmed its usefulness in the diagnosis of AIHA.

eSwab is a multi-purpose collection and transport system that employs flocked swab and 1 mL of improved liquid Amies medium. We examined the usefulness of group-A hemolytic streptococcal antigen rapid and culture tests to confirm whether eSwab can be used for multiple purposes. eSwab was evaluated by conducting three studies using Seed Swab No. 3 and the cotton swab attached to the antigen test kit as comparison targets. Antigen test results were similar between eSwab and Seed Swab No.3. In culture tests, the amount of Streptococcus pyogenes that grew when using eSwab was more than that of Seed Swab No. 3. In the comparison of storage performance, the numbers of viable S. pyogenes in eSwab and Seed Swab No.3 remained almost constant in refrigerated storage. The results of the group-A hemolytic streptococcal rapid antigen test of clinical specimens collected by eSwab showed a sensitivity of 92.3%, a specificity of 100%, and an overall matching rate 97.9%. In the culture test, eSwab showed the same or a larger number of bacterial cells than Seed Swab No. 3. The sensitivity of eSwab was lower than that of cotton swab attached to the kit during the antigen test, but it was consistent with the sensitivities described in the package insert. As a result, it is considered that the use of eSwab in the group-A hemolytic streptococcal rapid antigen test has no performance problem. We consider that eSwab can be used for both culture and antigen tests. The advantage of using a sample collection container with a liquid medium is that one sample can be used in multiple tests. To capitalize on eSwab strengths, further studies including its use for viruses are necessary in the future.

Grocott’s methenamine silver staining is one of the commonly used methods in histological analysis and widely used to screen for fungal microorganisms. Some fungal species have small amounts of the hydroxy group in their cell walls; thus, the conventional protocol of Grocott’s staining, including the use of chromate for oxidation, sometimes gives weak staining. In addition, tissue sections after the antigen retrieval step, which is often used in immunohistochemical analysis, show weak staining of the connective tissue. In this letter, we report the results of our tests using several types of acid for oxidation and pretreatment in the original Grocott’s staining for the detection of Mucor spp. in sections as an example. Among the acids we tested, we found periodic acid to be the best oxidation agent for Mucor spp. This modification using periodic acid is useful for identifying Mucor spp. in tissue sections especially when a commercially available antibody to Rhizopus does not provide satisfactory staining.

The optimal treatment for patients with bacteremia caused by penicillin-susceptible Staphylococcus aureus (PSSA) has not been established; however, recent evidence suggests that penicillin G (PCG) may be useful. Since anti-staphylococcal penicillins are not approved in Japan, cefazolin (CEZ) is the first agent of choice for the treatment of bacteremia caused by methicillin-susceptible S. aureus (MSSA), including PSSA. However, because of problems with the supply of raw materials and a new manufacturing process, it became difficult to maintain a stable supply of CEZ in 2019. The supply system was restored one and a half years later, but the same situation may occur in the future. It is beneficial to use PCG in the β-lactamase production test to confirm PSSA positivity. In this study, we performed penicillin disk zone edge tests on 26 MSSA strains isolated from blood cultures at our hospital over the past 4 years and were determined to be susceptible to PCG with a minimum inhibitory concentration (MIC) of ≤ 0.12 μg/mL. It was found that two strains were detected by the penicillin disc zone edge test. On the other hand, a zone edge test was also performed on 70 strains that had been isolated from materials other than blood, such as sputum, urine, stool, pus, and joint fluid, and could be preserved. None of these strains were detected. β-lactamase production detected by the penicillin disk zone edge test should be confirmed to provide useful information for selecting the appropriate antimicrobial agent before reporting PSSA positivity on the basis of MIC values indicating sensitivity to PCG.

The one-stage assay (OSA) for factor VIII activity (FVIII:C) measurement has been widely used, but its accuracy depends on the composition of APTT reagents. Therefore, we conducted a basic study of the coagulation FVIII:C quantification reagent “Revohem FVIII synthetic substrate” used in chromogenic assay, and compared this chromogenic assay with OSA using archived plasma samples. As a result, the simultaneous reproducibility CV was from 0.95 to 1.14% and the daily reproducibility CV was 2.15 to 4.13%. The correlations of CSA with the fivefold dilution of OSA and the 20-fold dilution of OSA were good (r = 0.99, y = 1.04x − 1.24; r = 0.99, y = 0.99x + 4.46, respectively). No interfering substances were observed. In a comparative study between CSA and OSA, there were discrepancies in the number of patients with LA positivity and those with hemophilia A under emicizumab therapy. From the above results, it can be said that the coagulation factor VIII quantification reagent “Revohem FVIII synthetic substrate” used in chromogenic assay is sufficiently compatible with tests routinely performed. CSA is less susceptible to LA and emicizumab than OSA.

Round cells are a new type of renal tubular epithelial cell. The current Japanese “Examination of Urinary Sediment 2010” does not mention round cells, which were observed in this study. In our previous study, we found round cells in urinary samples collected from patients with end-stage renal disease, and their number was found to correlate with the severity of chronic kidney disease. However, their existence in samples from healthy donors has not been reported. The purpose of this study is to examine urinary samples for round cells in urinary sediment. Urinary samples were collected from 78 healthy donors. Urinary sediment was examined by a standard method in accordance with the 2010 GP1-P4 guideline. Round cells were counted in whole fields (WFs) under 100× magnification, and microscopy images were captured. Cell size was determined using Image J. In this study, we detected round cells in samples from healthy donors.The cytoplasm was of the homogeneous or granular-vacuum type. The average size of round cells was 15.38 ± 1.84 μm. The viability rate of cells with the homogeneous-type cytoplasm was higher than that of cells with the granular-vacuum-type cytoplasm. This study confirmed that living round cells can be detected in samples from healthy donors.

We evaluated the IFCC-based reagent kit LUMIPULSE Presto TSH IFCC. The within-run and between-day precisions were 0.7–1.2%, and 1.0–1.1%, respectively. The diluted linearity and lower limit of detection were 176.20 and 0.006 μIU/mL, respectively. There were no significant differences in results between autodilution and manual dilution. The correlation coefficient (r) between LUMIPULSE Presto TSH IFCC and LUMIPULSE Presto TSH was 0.999. The stability of serum in storage was high in LUMIPULSE Presto TSH IFCC. A good correlation was obtained in the comparison between serum and heparin plasma levels. The basal performance of the LUMIPULSE Presto TSH IFCC is satisfactory and it can be used for measurements with high sensitivity.

A fully automatic blood transfusion test device can prevent dispensing errors, eliminate individual differences in agglutination judgment, and minimize labor saving. We conducted a basic study of irregular antibody screening by the gel column agglutination method (Gel-CAT) using the fully automatic blood transfusion test device Erytra Eflexis^®. The device was not affected by abnormal levels of colours routinely encountered in chylothorax, hemolysis, and hyperbilirubinemia. It was only affected by a high immunoglobulin level at IgG 7,371 mg/dL in the low-ionic-strength solution indirect antigulobulin test (LISS-IAT) and in specimens that produced rouleaux formation in the enzymatic method using papain. In the comparison of Gel-CAT with the glass-bead-based column agglutination method (Glass-CAT) using this device, Gel-CAT showed strong reaction intensity with anti-Kidd, anti-Duffy, and anti-Diego antibodies in LISS-IAT, and both anti-e and anti-Dia antibodies were detectable only by Gel-CAT. In the enzymatic method, Gel-CAT showed a strong reaction intensity with anti-Rh, anti-Kidd, and anti-Lewis antibodies, and three anti-Rh antibodies and two anti-Kidd antibodies were detected only by Gel-CAT. In samples with early antibody production, anti-E antibodies were detected earlier by Gel-CAT with the enzymatic method using papain. Gel-CAT detected anti-Jkb, anti-Dia, and anti-Lea antibodies similarly to PEG-IAT. Gel-CAT was particularly effective in detecting anti-Rh antibodies. For anti-D antibodies, the detection sensitivities were 0.02 IU/mL for LISS-IAT and 0.01 IU/mL for the enzymatic method using papain. Therefore, we concluded that Eflexis is useful for routine tests.

The event recorder (ER) is a non-invasive long-term ECG recording tool that is equipped with an automatic arrhythmia detector and can be used continuously for 1–2 weeks. It has a greater detection rate for arrhythmic events (AEs) than a 12-lead ECG equipment or 24-hour Holter monitor. In this study, we investigated the reasons for the use and the AE detection rate of ER. We also determined whether changes in medical treatment were made after AE detection. Nearly 80% of the respondents gave causal AE detection as the reason for the use of ER for monitoring symptoms. The AE detection rates were 24.8% in symptomatic patients, 46% in patients with syncope, and 9.7% in asymptomatic patients. The ER is useful for detecting clinically relevant arrhythmia(s) for patients with or without symptoms. The detection rate for the initial AE on the first day of using ER, which is equivalent to 24-hour Holter monitoring, was 37.5%, but it increased to 62.5% when extended up to 7 days; 84.4% of the initial AE was detected within the first three days. On the basis of the collected data, the AE detection rate increased with the time of using ER. However, a higher AE detection rate can be expected in a 3-day monitoring, if longer-term ER is not available. Medical treatment was changed in 59.4% of patients with AE detected by ER. From these data, it is concluded that ER is a useful tool for selecting the appropriate medical treatment on the basis of the actual detection of AE.

Smart Gene^® Myco (Smart Gene) is a gene testing kit that simultaneously and rapidly detects Mycoplasma pneumoniae (Mp) DNA and the macrolide resistance gene mutation. We studied the usefulness of Smart Gene in pediatric Mp pneumonia. Pharyngeal swab specimens were collected during a one-year period from April 2019. Specimens were collected from 146 patients (aged 7 months to 14 years and 7 months) who were hospitalized for pneumonia at the Pediatric Department of our hospital. Mp gene testing was performed using Smart Gene and the loop-mediated isothermal amplification (LAMP) method. Smart Gene detected Mp DNA in 43 patients, and the macrolide resistance gene mutation positivity rate was found to be 25.6% (11/43). We found a high agreement rate between Smart Gene and the LAMP method for detecting Mp DNA; the agreement rate for positivity was 95.5%, the agreement rate for negativity was 99.0%, and the overall agreement rate was 97.9%. The macrolide resistance gene mutation test showed that seven patients were resistance-gene-positive and eight patients were resistance-gene-negative; on the basis of these findings, their antimicrobials were changed. Ultimately, 9.1% (1/11) of the resistance-gene-positive patients and 93.8% (30/32) of the resistance-gene-negative patients were treated with macrolides (p < 0.01). Smart Gene can rapidly and efficiently detect Mp DNA and the macrolide resistance gene mutation and is a valuable gene test method for the rapid choice of the appropriate antimicrobials in pediatric Mp pneumonia.

When diagnosing spontaneous bacterial peritonitis (SBP), the low positivity rate of the ascitic fluid culture test is an issue. Studies on the usefulness of the blood culture test in SBP diagnosis have been relatively limited to date. Thus, we conducted a retrospective study to evaluate an appropriate diagnostic method for SBP. We analyzed 59 cases of SBP [22 cases in the group found positive for the causative bacteria by the ascitic fluid culture test (hereafter the ascitic-culture-positive group) and 37 cases in the group found negative for the causative bacteria (hereafter the ascitic-culture-negative group)] treated at our hospital from July 2012 to December 2019. The ascitic-culture-negative group was defined as having an ascitic fluid neutrophil count of 250/μL or more. Blood samples for culture were collected in 72.9% of cases (43/59 cases), all of which were a two-set collection. Among the 43 cases with blood samples collected, 48.8% (21/43 cases) were positive for the causative bacteria in their blood cultures: 70.0% of cases in the ascitic-culture-positive group and 30.4% of cases in the ascitic-culture-negative group were found positive for the causative bacteria by the blood culture test (p < 0.05). Four of the seven cases who were found negative by the ascitic fluid culture test but positive by the blood culture test had been treated with antibiotics before the collection of ascitic fluid for culture. The findings showed that the positivity rate of the blood culture test in SBP was relatively high, even in the ascitic-culture-negative group, suggesting the importance of performing blood culture tests before the administration of antibiotics. In the detection of causative bacteria, this study addresses the role of laboratory technicians in diagnostic stewardship, that is, to inform medical doctors on the appropriate method for taking samples.

In this study, we examined the impact of the outbreak of coronavirus disease 2019 (COVID-19) on pulmonary function tests (PFTs) in Hokkaido. We conducted a questionnaire survey involving 160 institutions to which members of the Hokkaido Association of Medical Technologists belong. In 122 institutions (73.5%), the number of PFTs conducted decreased in 2020 compared with that in 2019. The decrease was mostly observed for PFTs before operation and for annual check. In 95 (57.2%) institutions, PFTs for nonessential and nonurgent cases were restricted. To prevent the spread of COVID-19 infection, 126 (78.8%) institutions performed sterilization, 120 (75.0%) measured body temperature at the entrance, 136 (85.0%) had their medical staff wear surgical masks, and 121 (75.6%) had their staff wear face shields or/and goggles in addition to masks. The impact of the outbreak of COVID-19 on PFTs was huge, and it became evident that a number of institutions were still obliged to restrict the number of PFTs. A guideline for PFTs with infection control measures is required in times of an outbreak of COVID-19.

Since a pathological diagnosis is directly linked to the treatment of patients, pathological technologists should prepare high-quality specimens for precise diagnosis. Hematoxylin–eosin (HE) staining is one of the most important tools for the pathological diagnosis. However, it is difficult to obtain consistent results because of differences in the staining procedure carried out among laboratories. For accurate pathological diagnosis, HE-stained specimens of the highest quality should be prepared. Therefore, the standardization of the HE staining color that is consistent among all laboratories is indispensable for preparing high-quality specimens. As the first step for standardization, we asked pathological technologists and pathologists working at pathological divisions of hospitals in the Chubu district, Japan, to evaluate the color of the prepared specimens sent by e-mail as images in attached files, which were also used in the control survey carried out in 2017–2018 by the Aichi Association of Medical Technologists. We requested them to select the specimen they most favored among the HE-stained specimens with a wide spectrum of colors. In conclusion, the response summary showed that the pathologists generally favored a deeper eosinophilic tint than the pathological technologists and that there was diversity in preferences among the pathological technologists even in the same laboratory. A range of preferences among medical professionals was also revealed. This questionnaire survey could be helpful to standardize the HE staining procedure.

Following the partial amendment of the Act on Clinical Laboratory Technicians in June 2014, clinical laboratory technicians are now allowed to collect specimens other than blood. Consequently, in our hospital, they now have a wider range of duties. As clinical laboratory technicians are assigned as members of nurse-support teams, they are now in charge of ward blood collection, which was previously performed by nurses. With respect to skin and nail collection, owing to the lack of full-time dermatologists, patients with suspected scabies or ringworm had to either wait to be examined until a dermatologist is available or have their skin and nail specimens collected by nurses. Many of the skin samples collected by nurses keratinize. In 2011, an increase in the number of ward patients with scabies led to an increase in the frequency of microscopic examinations; thus, clinical laboratory technicians took charge of skin sampling. In response to the COVID-19 pandemic, our hospital began to conduct PCR and antigen tests in 2020; laboratory technicians are now in charge of taking nasopharyngeal swabs. Clinical laboratory technicians are responsible for the entire process of collecting suitable specimens for tests and data reporting, and this has improved the quality of tests. The shortage of physicians and nurses may become a serious problem in the future. Therefore, the collection of specimens by clinical laboratory technicians does not just represent a mere shift of tasks, but may also promote team-based medical care by enabling clinical laboratory technicians to utilize their specialized skills and capabilities.

With the Partial Amendment of Medical Care Act (Act No. 57 of 2017), the preparation of a system securing the accuracy of specimen inspection in medical institutions has become necessary. It is required to perform internal quality control in all specimen inspections performed. For this quality control, it is important to evaluate technologists who are not in charge of routine work of general cerebrospinal fluid examination requiring microscope operation and morphological differentiation on the basis of the accuracy of internal quality control and educate them depending on the necessity. We developed an internal quality control method for general cerebrospinal fluid examination targeting technologists in charge of after-hour inspection and evaluated the outcome of the method performed for 5 years. In this method, a photo test, in which cells in photographs of cerebrospinal fluid taken in our hospital were classified, and a cell classification test, in which microscopy images of cells in pseudo specimens of cerebrospinal fluid prepared from peripheral blood were classified, were performed once a year. Technologists in charge who did not meet the passing criteria set for each test were re-educated until they passed. The percentage of technologists who passed the photo test was 100% excluding the results in 2016. On the other hand, the highest and lowest percentages of technologists who passed the cell classification test were 76.5 and 27.3%, respectively, showing a large variation, and the percentage of technologists who passed did not improve from 57.1% over the last 2 years. It was confirmed that internal quality control in general cerebrospinal fluid examination based on photographs alone was insufficient, and internal quality control using a practical method including microscope operation is necessary. In addition, it may also be necessary to reconsider the method and interval of re-education.

A total of 136 cases were reported as carbapenem-resistant Enterobacteriaceae bacterial infections (CRE infections) in Niigata Prefecture (excluding Niigata City) between September 2014 and December 2020. For these cases, we investigated 127 strains provided by medical institutions for drug resistance gene possession. Of the 127 strains we investigated, the carbapenemase gene was detected in five strains (3.9%). The genotype of four strains was IMP-1 and that of the remaining strain was IMI-1. Strains with the IMP-1 genotype have been reported from many areas nationwide, whereas those with the IMI-1 genotype are rare, which were detected in three cases nationwide as of 2019. The IMI-1-genotype strain carrying the carbapenemase gene was detected in the Enterobacter cloacae complex isolated from the exudate of a male patient in his 70s. CRE infections are defined in the Infectious Diseases Control Law and are important for infectious disease control. The detection rate and type of carbapenemase gene differ depending on the region, so it is important to determine the situation and characteristics of a certain region.

Blastocystis hominis is a protozoan that parasitizes the human large intestine and causes diarrhea and vomiting, but its pathogenicity remains unclear. In this paper, we report a case of diarrhea that was suspected to be due to B. hominis infection and was diagnosed on the basis of the results of staining methods. A man in his 80s had persistent diarrhea that was suspected to be due to a parasitic infection on the basis of Gram staining of his stool. Direct thin-layer smearing of the stool confirmed the parasite to be B. hominis. The reasons for considering this case as diarrhea caused by B. hominis were as follows: (1) trophozoites were detected, (2) no causative agent of diarrhea was identified, (3) the blood eosinophil count was high, and (4) digestive symptoms and eosinophilia were improved by taking metronidazole. However, since the causal relationship between (3) and (4) is not clear, it cannot be said that the diarrhea was caused by B. hominis, but it could be a case in which eosinophilia due to parasites was presumed. We attempted to compare techniques of staining B. hominis. The differential staining methods used were Gram staining, iodine staining, and Giemsa staining. Sternheimer (S) staining used for urine sediments was also performed. The stainability was good for all these methods. Our results suggest that S staining was the best method for observing internal structures. Since this simple and easy S staining can be performed in a relatively large number of facilities, it was considered an effective staining method for detecting B. hominis.

We report a case of endometrioid cancer arising from cecal endometriosis. A 30-year-old woman frequently visited our hospital for abdominal pain for 10 years. Her blood carbohydrate antigen 125 (CA125) level and medical histories were regularly examined because her mother had uterine cancer and her sister had ovarian cancer. Although a rectal echo observation was made, no obvious organic changes were observed. She was admitted to our hospital complaining of abdominal pain that had persisted for a few days. A target sign in the ascending colon was confirmed by abdominal ultrasonography and abdominal CT examination, and intussusception was noted. Moreover, a laparoscopic tumor was found during the reduction operation, and the ileocecal mass and the diverticulum of the sigmoid colon were excised. The histopathological diagnosis was endometriosis-associated intestinal tumor (EAIT) arising from the endometriosis of the cecum, and the histologic type was endometrioid cancer (Grade 2). Given her family history, breast and ovarian cancers were suspected, and genetic tests were recommended. The BRCA1/BRCA2 genetic test showed negative results. The BRAF V600E genetic test also showed negative results; thus, we suspected Lynch syndrome due to mismatch repair (MMR). Unfortunately, her family members chose not to have an MMR genetic test for a definitive diagnosis. It is difficult to detect intestinal endometriosis, but its lesion can be discovered by endoscopy or MRI if it is suspected and carefully observed. If abdominal pain coincides with menstruation, it is important to consider further examination with endometriosis in mind.

We detected ST elevation in Holter electrocardiography results when symptoms occurred. We encountered the case of a patient who was diagnosed as having effort angina pectoris (EAP) with coronary spastic angina (CSA). The patient was female in her 40s. About a month ago, she began to feel chest zonesthesia that radiated to the neck while resting in the morning, and she underwent Holter electrocardiography. Transient ST elevation with chest symptoms was detected on both NASA and CM5 inductions in the morning. On the other hand, transient ST elevation of a different type with chest symptoms was detected on the NASA induction in the evening on effort. In coronary angiography, mild spasm was found in the entire coronary artery. Stenosis of 99% was found in the anterior descending branch of the left coronary artery (segment 7). From the results of Holter electrocardiography and coronary arteriography, we diagnosed the patient as having EAP with CSA. The patient was treated with catheterization for EAP and calcium antagonists for CSA. Angina generally has EAP and CSA. We learned that we can accurately interpret results by understanding each characteristic and onset pattern if we encounter a relatively rare complication.

Mycoplasma hominis, a commensal inhabitant of the lower urogenital tract, cannot be stained by Gram staining and is resistant to β-lactam antibiotics. We report the cases of two female patients from whom M. hominis was isolated from their blood cultures after cesarean section. Case 1 was in her 20s who underwent emergency cesarean section because of arrested labor. Six days after the operation, she had abdominal pain and fever, and lochia accumulated in the vagina. Computed tomography (CT) showed fluid accumulation around the uterus. Case 2 was in her 30s who underwent emergency cesarean section because of increased levels of inflammatory markers and amniotic fluid turbidity. Eight days after the operation, because the levels of inflammatory markers continued to be high, CT was performed, the results of which showed peri-uterine abscess. In case 1, only one anaerobic bottle in two sets was positive on the 7th day of culture. In case 2, blood culture was negative after 7 days of culture, but M. hominis was observed in both sets when subculture was performed. In both cases, the colonies isolated from blood cultures and uterine-derived specimens showed Gram-negative granule structures and were identified as M. hominis by 16S rRNA genetic analysis. If the involvement of M. hominis is suspected on the basis of the patient’s background characteristics and clinical course, anaerobic culture and subculture should be performed even when the automated blood culture instrument shows negative results. Moreover, it is important to promptly convey information on appropriate antibiotics to the doctor in charge.

The risk of irregular antibody production after platelet transfusion seems to be low, since the number of red blood cells contained in platelet products is very small. However, we encountered the case of a patient with antibody production probably caused by platelet transfusion. The patient was a woman who presented with myelodysplastic syndromes (MDS). She had no history of red blood cell transfusion and her screening test for irregular antibodies showed negative results. The production of anti-E and anti-c antibodies after frequent platelet transfusions was considered. We reconfirmed that red blood cells in platelet preparations triggered an immune response. The IgM-type anti-c antibody affected the ABO blood group test results. These findings suggest that the test should be carried out considering the possibility of irregular antibody production, including those of the IgM type, after platelet transfusion.

[Background] Acute pulmonary thromboembolism (PTE) occurred in six patients in our hospital from July to December 2018. We have started using a system developed on the basis of an “algorithm for deep vein thrombosis (DVT) diagnosis” for all hospitalized patients. [Materials and Methods] This study included 6,341 patients hospitalized 12 months before and 12 months after application of the system. We performed lower extremity venous ultrasound in 1,676 patients. We compared the characteristics of patients ①with and without DVT and in terms of ②thrombus site classified into the proximal or distal type. Additionally, we compared ③the rate of DVT detection and the positivity rate of DVT before and after application. We also compared the three categories of DVT, namely, already existing, formed during hospitalization, and of unknown time of onset, and ④the incidence of PTE with and without shock. [Results] ①Patients with DVT were significantly more likely to be female, older, have a lower BMI, and have higher D-dimer levels. ②Patients with the proximal-type thrombus showed significantly higher D-dimer levels. ③The detection rate of the group with already existing DVT and the rate of DVT detection increased significantly. ④There was no significant difference in the incidence rate of PTE before and after the application of the system. However, there were no severe cases with shock after the application. [Conclusion] We were able to screen for cases of already existing DVT by using the system. This prevented the occurrence of severe PTE.