Tooth agenesis is the failure of tooth bud development, causing definitive absence of the tooth. It is the most common dental anomaly, affecting up to one-quarter of the general population. The main cause is related to abnormal function of specific genes which play key roles during odontogenesis, particularly MSX1 and PAX9. MSX1 is a transcription factor highly expressed in the mesenchyme of developing tooth germs, whereas PAX9 is a transcription factor that shows a direct relationship with craniofacial development, particularly the formation of the palate and teeth. Despite the high frequency of tooth agenesis, there are as yet only a restricted number of mutations in MSX1 and PAX9 that have been associated with non-syndromic tooth agenesis. Thus, a deeper analysis of the gene networks underlying this anomaly is imperative. By means of a literature review based on Medline, PubMed, Lilacs, NCBI, and STRING, performed between 1991 and 2010 and focused on etiologically associated mutations, this work aimed to assess the latest advances in the genetic etiology of tooth agenesis and to offer an insight into how they can assist dental practice in the near future. A better knowledge of the genetic networks underlying tooth agenesis will lead to better treatment options and, perhaps, a tool for early diagnosis possibly related to DNA examination based on polymorphic variants. Such a test based on DNA analysis may be available to and accessible by clinicians, resulting in a more accurate diagnosis and allowing for a better approach to this anomaly.
Tendinopathy is a serious health problem and its etiology is not fully elucidated. Among intrinsic and extrinsic predisposing factors of tendinopathy, the impact of therapeutic agents, especially fluoroquinolone (FQ) group antibiotics, is recently being recognized. FQs are potent bactericidal agents widely used in various infectious diseases, including community acquired pneumonia and bronchitis, chronic osteomyelitis, traveler's diarrhea, typhoid fever, shigellosis, chronic bacterial prostatitis, uncomplicated cervical and urethral gonorrhea and prophylaxis of anthrax. FQs have an acceptable tolerability range. However, many lines of evidence for developing tendinitis and tendon rupture during FQ use have resulted in the addition of a warning in patient information leaflets. FQ-induced tendinopathy presents a challenge for the clinician because healing response is poor due to low metabolic rate in mature tendon tissue and tendinopathy is more likely to develop in patients who are already at high risk, such as elderly, solid organ transplant recipients and concomitant corticosteroid users. FQs become photo-activated under exposure to ultraviolet light, and this process results in formation and accumulation of intracellular reactive oxygen species (ROS). The subsequent FQ-related oxidative stress disturbs mitochondrial functions, leading to apoptosis. ROS overproduction also has direct cytotoxic effects on extracellular matrix components. Understanding the mechanisms of the FQ-associated tendinopathy may enable designing safer therapeutic strategies, hence optimization of clinical response. In this review, we evaluate multi-factorial etiology of the FQ-induced tendinopathy and discuss proposed preventive measures such as antioxidant use and protection from natural sunlight and artificial ultraviolet exposure.
Diabetes has been reported to increase the risk of colorectal neoplasm in most but not all studies. However, the data on age- and sex-specific incidence rates and relative risks associated with diabetes are limited. We carried out this population-based cohort study to investigate the overall sex- and age-specific risks of colorectal cancer in association with diabetes. Diabetic patients (n = 615,532) and age- and sex-matched control individuals (n = 614,871), selected from the claim datasets, were followed up from 2000 to 2006. The rates of admission due to colon and rectum cancers were estimated using the person-years approach, and the age- and sex-specific hazard ratio (HR) for both the malignancies were determined using the Cox regression model. The overall incidence rate of colon cancer was 9.94 per 10,000 patient-years for the diabetic patients, as opposed to 7.84 per 10,000 patient-years for the control-group patients. The corresponding observation for rectal cancer was 7.16 and 6.28 per 10,000 patient-years. Diabetic patients aged ≥ 45 years had significantly high HRs for developing colon cancer (1.20-1.45-fold). We also noted a significantly high HR of rectal cancer in diabetic men (1.18-fold) aged ≥ 45 years, but not in diabetic women. In conclusion, diabetes may significantly increase the risk of colorectal cancer, especially in patients aged 45-64 years. Diabetologists should keep this relationship in mind while treating middle-aged diabetic men and should also advise these patients to undergo regular screening tests for colorectal cancer.
Glioblastoma multiforme is an aggressive brain tumor with a poor prognosis. The glioblastoma stem-like cells (GSCs) represent a rare fraction of human glioblastoma cells with the capacity for multi-lineage differentiation, self-renewal and exact recapitulation of the original tumor. Interestingly, GSCs are more radioresistant compared with other tumor cells. In addition, the remarkable radioresistance of GSCs has been known to promote radiotherapy failure and therefore is associated with a significantly higher risk of a local tumor recurrence. Moreover, the hyperactive cell cycle checkpoint kinase (Chk) 1 and 2 play a pivotal role in the DNA damage response including radiation and chemical therapy. Based on aforementioned, we hypothesized that knockdown of Chk1 or Chk2 might confer radiosensitivity on GSCs and thereby increases the efficiency of radiotherapy. In this study, we knocked down the expression of Chk1 or Chk2 in human GSCs using lentivirus-delivered short hairpin RNA (shRNA) to examine its effect on the radiosensitivity. After radiation, the apoptosis rate and the cell cycle of GSCs were measured with Flow Cytometry. Compared with control GSCs (apoptosis, 7.82 ± 0.38%; G2/M arrest, 60.20 ± 1.28%), Chk1 knockdown in GSCs increased the apoptosis rate (37.87 ± 0.32%) and decreased the degree of the G2/M arrest (22.37 ± 2.01%). In contrast, the radiosensitivity was not enhanced by Chk2 knockdown in GSCs. These results suggest that depletion of Chk1 may improve the radio-sensitivity of GSCs via inducing cell apoptosis. In summary, the therapy targeting Chk1 gene in the GSCs may be a novel way to treat glioblastoma.
Hydrogen sulfide (H2S) displays an anti-apoptotic activity against myocardial ischemia reperfusion (MIR). Apoptosis repressor with caspase recruitment domain (ARC) is constitutively expressed in the heart and inhibits cell apoptosis when it is phosphorylated. Here, we investigated whether H2S could inhibit apoptosis by affecting ARC phosphorylation using cultured rat cardiomyocytes and a rat model of MIR. Primary cardiomyocytes were prepared from hearts of newborn rats and were pre-incubated with NaHS, a donor of H2S, for 60 min. Cardiomyocytes were subjected to hypoxia for 4 h, followed by reoxygenation for 2 h. The hypoxia and subsequent reoxygenation (H/R) significantly induced cell apoptosis, increased expression levels of Fas and FasL proteins, enhanced release of cytochrome c from mitochondria, and elevated caspase-3 activity, while H/R reduced ARC phosphorylation and increased the activity of calcineurin that dephosphorylates ARC. Pre-incubation with NaHS significantly attenuated the above effects through promoting ARC phosphorylation by reducing calcineurin activity and by increasing the activity of protein kinase casein kinase II (CK2) that phosphorylates ARC. In fact, TBB, a specific inhibitor of CK2, abolished the effects of NaHS. In rats undergoing MIR, NaHS significantly reduced the myocardial infarct size, cell apoptosis, calcineurin activity, and the expression levels of Fas, FasL and cleaved caspase-3 proteins, while NaHS increased ARC phosphorylation. In contrast, DL-propargylglycine, an inhibitor of cystathionine γ-lyase, the main enzyme for H2S production in hearts, showed opposite effects to NaHS. The results indicate that H2S inhibits apoptosis of cardiomyocytes induced by MIR through enhancing ARC phosphorylation.
Interstitial lung diseases (ILDs) represent a large group of different diseases, with a large part comprising idiopathic interstitial pneumonias. Differentiating hypersensitivity pneumonitis (HP), especially its chronic form and other ILDs, is difficult because of similarities in radiological manifestation and clinical course, and the difficulty of identifying causative antigens. We recently experienced a patient with Cladosporium-induced chronic HP that developed in a household environment, but the cause had been misdiagnosed as idiopathic interstitial pneumonia for several years. This case highlighted the need for measures differentiating HP from idiopathic interstitial pneumonia. In this study, we examined fungal exposure in ILDs using an antibody titer in serum to identify possible fungus-related HP. We measured the antibody titer to Cladosporium spp. in 34 patients with various ILDs, 17 patients with bronchial asthma, and 21 control subjects using an immunofluorescence assay. ILDs included HP (5 patients), idiopathic interstitial pneumonias (21 patients), and ILDs with collagen vascular diseases (8 patients). Results showed a significantly higher tendency for high anti-Cladosporium antibody titers in ILD groups (12 patients out of 34 patients), compared to patients with bronchial asthma (0/17) or control subjects (0/21). This increase in antibody titers was observed not only in patients with HP, but also in those with idiopathic interstitial pneumonias and those exhibiting collagen vascular diseases with ILDs. This report highlights the pathogenic role of fungal antigens in various ILDs. In conclusion, fungi commonly observed in our living environment such as Cladosporium could be involved in the development of ILDs.
The hemochromatosis (HFE) gene encodes the HFE protein that regulates iron absorption. HFE mutations lead to the hemochromatosis disease of excessive iron absorption. HFE mutations may also influence the sustained virologic response (SVR, long-term virus suppression) in chronic hepatitis C patients treated with interferon-based antiviral therapy. We performed a meta-analysis of all English and Chinese language studies of HFE mutations and SVR in interferon-treated chronic hepatitis C patients indexed in the Medline, PubMed, Embase, and China National Knowledge Infrastructure databases to November 2011. Seven studies involving 605 patients with HFE mutations (homozygous or heterozygous mutation of C282Y, H63D or S65C) and 1279 with wild-type HFE (no mutation of C282Y, H63D or S65C for both alleles) were analyzed. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated with the fixed- or random-effect models. HFE mutations were associated with significantly higher SVR rate (vs. wild-type: OR = 1.56, 95% CI: 1.23 - 1.97, P < 0.001), indicating that mutation carriers were likely to achieve SVR in response to interferon-based antiviral therapy. Stratification analysis by HFE mutation type revealed that the H63D mutation was associated with a significantly higher SVR rate (OR = 1.60, 95% CI: 1.09 - 2.34, P = 0.020), while the C282Y mutation was not (OR = 1.19, 95% CI: 0.71 - 1.98, P = 0.510). Our meta-analysis results indicate that the H63D mutation in HFE is associated with a higher SVR rate in chronic hepatitis C patients treated with interferon-based antiviral therapy.
Esophageal squamous cell carcinoma (ESCC) is a predominant type of esophageal cancer, which is a malignant tumor originating from the esophageal mucosa or gland and is aggressive with poor prognosis. Identification of new gene expression patterns would be helpful for providing new targets for the early detection and treatment of ESCC patients. In the present study, we employed cDNA array technology to compare gene expression profiles between ESCC tissues and adjacent normal epithelial tissues from ESCC patients. There was at least a 4-fold change in the expression levels of 72 genes that were significantly increased and 107 genes that were decreased in ESCC compared with normal esophageal epithelium. Among them, genes known to be involved in ESCC were found, including matrix metalloproteinases, transcription factors SOX-4 and SOX-17, the Wingless-type MMTV integration site family member 2, and cell cycle regulators. Moreover, we have newly identified the two genes that are down-regulated in ESCC: monoamine oxidase A, an enzyme that catalyzes monoamines oxidation and 15-hydroxyprostaglandin dehydrogenase [NAD+], a prostaglandin-synthesizing enzyme that physiologically antagonizes COX-2. Likewise, we found the three genes that are up-regulated in ESCC: CD7, a cell surface glycoprotein member of the immunoglobulin superfamily, LIM-domain kinase 1, a small subfamily with an unique combination of two N-terminal LIM motifs and a C-terminal protein kinase domain, and TTK protein kinase, a previously unidentified member of the kinase family. These newly identified genes may be involved in the progression of the tumor and/or represent properties specific to ESCC.
Nontuberculous mycobacteria (NTM) diseases are in the face of a progressive increase even in immune-competent subjects, and the clinical features of NTM diseases are heterogenous. The decision to institute treatment of the patients should be made after a period of follow up, because therapy is often prolonged, and frequently ineffective. The reasons why some patients develop severe NTM diseases are not clear. Here we observed the involvement of latent tuberculosis infection (LTBI) in clinical and laboratory features of NTM diseases. We evaluated various tuberculosis-related inflammatory markers including osteopontin (OPN), pentraxin-3 (PTX-3), and soluble IL-2 receptor (sIL-2R) in NTM infected patients with or without LTBI. Eight NTM and 5 tuberculosis (TB) patients, and 5 healthy subjects were enrolled. Polymerase Chain Reaction (PCR) analysis confirmed the absence of tuberculosis specific gene (RD1 region), among clinical isolates from NTM patients. Interferon-γ (IFN-γ) release assay (IGRA) using Early Secreted Antigenic Target-6 (ESAT-6) and CFP-10, the RD1-encoded protein, was employed for determining LTBI. IGRA was positive in 4/8 NTM (NTM with LTBI, 50%) and 5/5 TB patients. Only 2 of 4 NTM with LTBI were under chemotherapy among all NTM patients, and others were followed up. The plasma levels of OPN, PTX3 and sIL-2R were significantly higher in NTM patients with LTBI than in those without LTBI (P < 0.05). The two patients under therapy showed the highest OPN levels that persisted after treatment. The increased inflammatory levels in NTM patients with LTBI indicate enhanced inflammatory reaction. Extensive therapy may be necessary in such patients.