Living organisms enantioselectively employ L-amino acids as the molecular architecture of protein synthesized in the ribosome. Although L-amino acids are dominantly utilized in most biological processes, accumulating evidence points to the distinctive roles of D-amino acids in non-ribosomal physiology. Among the three domains of life, bacteria have the greatest capacity to produce a wide variety of D-amino acids. In contrast, archaea and eukaryotes are thought generally to synthesize only two kinds of D-amino acids: D-serine and D-aspartate. In mammals, D-serine is critical for neurotransmission as an endogenous coagonist of N-methyl D-aspartate receptors. Additionally, D-aspartate is associated with neurogenesis and endocrine systems. Furthermore, recognition of D-amino acids originating in bacteria is linked to systemic and mucosal innate immunity. Among the roles played by D-amino acids in human pathology, the dysfunction of neurotransmission mediated by D-serine is implicated in psychiatric and neurological disorders. Non-enzymatic conversion of L-aspartate or L-serine residues to their D-configurations is involved in age-associated protein degeneration. Moreover, the measurement of plasma or urinary D-/L-serine or D-/L-aspartate levels may have diagnostic or prognostic value in the treatment of kidney diseases. This review aims to summarize current understanding of D-amino-acid-associated biology with a major focus on mammalian physiology and pathology.
Obturator hernia (OH) is a rare condition that accounts for 0.073–1% of abdominal hernias and 0.48% of bowel obstructions. OH frequently occurs in elderly women, with an incidence that increases with age. The only treatment for OH is surgical intervention, and the approaches used vary greatly. Consequently, a well-defined consensus has not yet emerged. We assessed the efficiency and safety of the midline extraperitoneal approach for OH. Six patients with OH repaired using the midline extraperitoneal approach at KKR Sapporo Medical Center between April 2011 and January 2016 were included in the study. We retrospectively evaluated the patient characteristics, intraoperative findings, and the postoperative course. All patients were elderly women [median age, 90 (range, 79–92) years], with a median body mass index of 17.0 (range, 15.6–18.3) kg/m2 at presentation. All had symptoms associated with bowel obstruction: two patients presenting with leg pain had the Howship–Romberg sign. In two patients, bowel resection was required because of irreversible ischemic changes. Five patients had coexisting femoral and inguinal hernias that were repaired by bilateral mesh repair. One patient had aspiration pneumonia as a postoperative complication. All patients were discharged alive, without infection or recurrence. OH can be efficiently and safely repaired using the midline extraperitoneal approach. This approach establishes the diagnosis of OH, avoids injuring obturator vessels, gives improved exposure of the obturator canal, enables identification and simultaneous repair of other pelvic hernias, and facilitates bowel resection. This approach reduces the risk of mesh infection in patients undergoing bowel resection.
Mesenchymal stem cells (MSCs) have generated great interest in the fields of regenerative medicine and immunotherapy because of their unique biological properties. Among MSCs, amniotic fluid stem cells (AFS) have a number of characteristics that make them attractive candidates for tissue engineering and cell replacement strategies, particularly for perinatal medicine. If various neonatal conditions, including birth asphyxia, preterm birth, and congenital abnormalities, which result in long-lasting severe impairments, could be predicted during pregnancy, it would allow collection of small samples of amniotic fluid cells by amniocentesis. In vitro culture of these autologous AFS during pregnancy would make them available for use soon after birth. Hypoxic-ischemic encephalopathy (HIE) and myelomeningocele (MMC) are neonatal conditions that cause permanent neurological disability, for which the treatment options are extremely limited. Experiments using animal models of HIE and MMC and human clinical trials have demonstrated that MSCs, including AFS, have beneficial effects on the central nervous system through paracrine influences, indicating that autologous AFS treatment may be applicable for intractable neurological diseases, including HIE and MMC, during the perinatal period. In this review, we focus on recent research related to the therapeutic potential of AFS for perinatal neurological diseases such as HIE and MMC.
The aim of this study was to evaluate the effects of transcorneal electrical stimulation in subjects with primary open-angle glaucoma. Five eyes of four male subjects with primary open-angle glaucoma (average age: 52.25 ± 14.68 years) were enrolled. The subjects underwent transcorneal electrical stimulation every 3 months according to the following procedure. A Dawson-Trick-Litzkow electrode was placed on the cornea, and biphasic electric current pulses (10 ms, 20 Hz) were delivered using a stimulator (BPG-1,BAK Electronics) and a stimulus isolation unit (BSI-2). A current that evoked a phosphene that the subject perceived in the whole visual area was delivered continuously for 30 min. Humphrey visual field testing was performed after every third transcorneal electrical stimulation treatment. Changes in mean deviation (MD) values were evaluated with a linear regression model. Transcorneal electrical stimulation was performed 18.2 ± 9.4 times over a period of 49.8 ± 23.0 months. The average pretranscorneal electrical stimulation intraocular pressure, best corrected visual acuity, and MD values were 11.8 ± 1.79 mmHg, 0.14 ± 0.19 (logMAR) and −17.28 ± 6.24 dB, respectively. No significant differences were observed in intraocular pressure before and after transcorneal electrical stimulation. However, there was a significant positive linear relationship between changes in MD values and the number of transcorneal electrical stimulation treatments (R2 = 0.176, P = 0.005, Spearman correlation R =0.294, P = 0.008). Transcorneal electrical stimulation treatment may improve glaucomatous visual field defects in subjects with primary open-angle glaucoma. Large-scale studies are necessary to confirm these preliminary findings.
In this study, we investigated the correlations between biochemical and hematological test results obtained using microliter-scale fingertip blood samples collected with a newly developed blood collection device and those obtained using conventional venous blood. Eighty volunteer subjects were enrolled in this study. Blood samples were drawn from the fingertip of the ring finger by a single puncture, and 60-µL samples were promptly and accurately aspirated into a blood collection chip. Then the chip was tightly sealed in a chip container and was shaken to mix the contents without dispersion. For biochemical tests other than that for HbA1c, blood was collected without anticoagulant and centrifuged to obtain 15 µL of serum which was then diluted with 190 µL of physiological saline for the assay. For hematological tests and the test for HbA1c, the sample was assayed with blood collected using EDTA-2 K. Good correlations were obtained between the test results of the assay using fingertip blood and that using venous blood. The correlation coefficients were ≥0.97 for TG, T-CHO, HDL-C, LDL-C, GLU, ALT, γ-GTP, UA, BUN, and HbA1c and ≥0.95 for WBC, RBC, Hgb, and Hct. These results suggest that our microliter-scale blood testing system is comparable to assays using venous blood and may be useful as a rapid and simple test to determine basic clinical parameters that are close to the reference intervals.
Depression is common among cancer patients and their families, and may lead to in substantial clinical consequences. Clinicians should routinely screen cancer patients for comorbid depression and should provide appropriate care at both primary and specialized care levels. Good quality care is beneficial not only for cancer patients themselves but also for their family members. It includes good communication between patients and health providers, and addressing of unmet needs of cancer patients. Specialized care comprises pharmacotherapy and psychotherapy. The advancement of psychotherapy for cancer patients parallels the advancement of general psychotherapy. Among the many types of psychotherapies, mindfulness-based interventions have been attracting growing attention. Some relevant studies that have been conducted in Keio University Hospital are described herein.
Unlinked total elbow arthroplasty (TEA), which has no mechanical connection between the humeral and ulnar components, has theoretical advantages based on its near-normal elbow kinematics and the preservation of bone stock. Unlinked TEA is appropriate only for patients who have limited bone loss or limited deformity and good ligamentous function. This is because postoperative instability has been a major complication of unlinked prostheses. The concept and goal of unlinked TEA is to share the loading stress on the bone implant interface with the surrounding tissues. Although the loosening rate of unlinked prostheses theoretically should be lower than that of linked prostheses (which have a mechanical connection between the humeral and ulnar components), there is no clear evidence that unlinked TEAs are superior to linked TEAs in this respect. However, we believe that primary TEA should be performed using an unlinked TEA, especially for younger patients, because revision surgery for unlinked TEA results in longer prosthesis survival than revision surgery for linked TEA. Improvement of the design of unlinked prostheses and the introduction of less invasive surgical techniques are required to reduce postoperative instability.