Autosomal dominant cerulean cataract is associated with a chain termination mutation in the human beta-crystallin gene CRYBB2

Congenital cataracts are a common major abnormality of the eye that frequently cause blindness in infants. At least a third of all cases are familial; autosomal dominant congenital cataract (ADCC) appears to be the most common familial form in the Western world. Cerulean cataracts have peripheral bluish and white opacifications in concentric layers with occasional central lesions arranged radially. Although the opacities may be observed during fetal development and childhood, usually visual acuity is only mildly reduced until adulthood, when lens extraction is generally necessary. We have been studying a family (ADCC- 1) with cerulean blue ADCC, in which the affected daughter of a first cousin mating was presumed to be homozygous for the cataract gene. Recently, we mapped an ADCC gene in this family to a region of chromosome 22 containing three beta-crystallin genes. Here we report that a chain-termination mutation in CRYBB2 is associated with ADCC in this family.      

The orphan receptor ALK7 and the Activin receptor ALK4 mediate signaling by Nodal proteins during vertebrate development

Nodal proteins have crucial roles in mesendoderm formation and left-right patterning during vertebrate development. The molecular mechanisms of signal transduction by Nodal and related ligands, however, are not fully understood. In this paper, we present biochemical and functional evidence that the orphan type I serine/threonine kinase receptor ALK7 acts as a receptor for mouse Nodal and Xenopus Nodal-related 1 (Xnr1). Receptor reconstitution experiments indicate that ALK7 collaborates with ActRIIB to confer responsiveness to Xnr1 and Nodal. Both receptors can independently bind Xnr1. In addition, Cripto, an extracellular protein genetically implicated in Nodal signaling, can independently interact with both Xnr1 and ALK7, and its expression greatly enhances the ability of ALK7 and ActRIIB to respond to Nodal ligands. The Activin receptor ALK4 is also able to mediate Nodal signaling but only in the presence of Cripto, with which it can also interact directly. A constitutively activated form of ALK7 mimics the mesendoderm-inducing activity of Xnr1 in Xenopus embryos, whereas a dominant-negative ALK7 specifically blocks the activities of Nodal and Xnr1 but has little effect on other related ligands. In contrast, a dominant-negative ALK4 blocks all mesoderm-inducing ligands tested, including Nodal, Xnr1, Xnr2, Xnr4, and Activin. In agreement with a role in Nodal signaling, ALK7 mRNA is localized to the ectodermal and organizer regions of Xenopus gastrula embryos and is expressed during early stages of mouse embryonic development. Therefore, our results indicate that both ALK4 and ALK7 can mediate signal transduction by Nodal proteins, although ALK7 appears to be a receptor more specifically dedicated to Nodal signaling.     

Evaluation of predominant risk factors for type 2 diabetes mellitus among out-patients in two Nigerian secondary health facilities

BackgroundPrevention of type 2 diabetes is enabled by identification and effective management of risk factors.ObjectivesTo evaluate the predominant risks for type 2 diabetes and identify persons at highest risk in a population; to facilitate the understanding of implications for practice.MethodsCross-sectional survey using Canadian diabetes risk assessment questionnaire was conducted among non-diabetic persons who visited two secondary hospitals. SPSS version 18 was used for data analysis.ResultsA total of 300 respondents participated in the study, with 25.7% having family history of type 2 diabetes, while 160 (53.3%) were at high risk of developing the disease. Males (62.5%), overweight (65.1%) and obese (82.6%) participants, were at higher risk. Others found to be at high risk were respondents with high waist circumference (55.6%), respondents who did not exercise (77.0%), those who did not eat fruits/vegetable daily (54.4%), those with high blood pressure (67.5%) and those who have had raised blood sugar in the past (71.0%).ConclusionMajority of the study participants was at high risk for type 2 diabetes, male participants had higher risks and lifestyles/habits were the major risks for developing the disease..     

Hyaluronan Enhances Bone Marrow Cell Therapy for Myocardial Repair After Infarction

Hyaluronan (HA) has been shown to play an important role during early heart development and promote angiogenesis under various physiological and pathological conditions. In recent years, stem cell therapy, which may reduce cardiomyocyte apoptosis, increase neovascularization, and prevent cardiac fibrosis, has emerged as a promising approach to treat myocardial infarction (MI). However, effective delivery of stem cells for cardiac therapy remains a major challenge. In this study, we tested whether transplanting a combination of HA and allogeneic bone marrow mononuclear cells (MNCs) promotes cell therapy efficacy and thus improves cardiac performance after MI in rats. We showed that HA provided a favorable microenvironment for cell adhesion, proliferation, and vascular differentiation in MNC culture. Following MI in rats, compared with the injection of HA alone or MNC alone, injection of both HA and MNCs significantly reduced inflammatory cell infiltration, cardiomyocyte apoptosis, and infarct size and also improved cell retention, angiogenesis, and arteriogenesis, and thus the overall cardiac performance. Ultimately, HA/MNC treatment improved vasculature engraftment of transplanted cells in the infarcted region. Together, our results indicate that combining the biocompatible material HA with bone marrow stem cells exerts a therapeutic effect on heart repair and may further provide potential treatment for ischemic diseases.     

The effect of EDTA, cations, and various buffers on the morphology of erythrocyte membranes: an electron-microscopic study

Membranes of human erythrocytes were prepared by stepwise osmotic hemolysis in Ca2+-free solutions. Examination with the electron microscope after negative staining showed some short, conelike protuberances on the surface of about 20 percent of the ghosts, while 80 percent were round, intact spheres. After Ca2+ treatment, all membranes were round and intact. After exposure to ethylenediaminetetraacetic acid (EDTA) (1.0 mM, pH 7.4), the entire ghost surface was covered with long, thin extrusions called stromalytic forms (about 460 per cell). Their sizes, shapes, and fine structure are described. Exposure to ionic calcium (1.4 times 10-minus 4M) abolished the EDTA-induced stromalytic forms. A second exposure to EDTA reversed this Ca2+ effect. ATP, like EDTA, produced stromalytic forms. EDTA- induced stromalytic forms were also abolished by Zn2+, La3+, and Nd3+ at concentrations of 1-5 times 10-minus 4 M. Mg2+ at 10-minus 2 M was ineffective. Ghosts were prepared by graded lysis in various buffers. Those prepared in phosphate were the most stable and provided consistent EDTA effects and Ca2+ reversal. Ghosts in Tris-HCl showed breakdown unless salt was added. Moderately satisfactory ghosts were also obtained in Hepes-NaOH buffer and salt.     

Clinical,laboratory and radiological features and outcomes of moderate to severe COVID-19 patients: A descriptive retrospective study

Objective: To describe the clinical, laboratory and radiological characteristics and outcomes of moderate-to-severe coronvirus disease 2019 (COVID-19) patients.Methods: We retrospectively analyzed 43 RT-PCR confirmed moderate-to-severe COVID-19 patients who were admitted to a tertiary care center. The primary composite outcomes were admission to intensive care unit, requirement of mechanical ventilation, and death. Results: The median age of the patients was 50 years, and 62.8％ of the patients were male. Out of 43 patients, 15 (34.88％) were categorized as severe. A total of 26 (60.47％) patients had 1 or more comorbidities [diabetes (34.88％) and hypertension (30.23％)]. The median duration from the onset of symptoms to admission was 3 days, and the most common symptoms were dyspnoea (90.7％), cough (79.07％), fever (69.77％), and body ache (46.51％). Leucopenia was presented in 14 (32.56％) patients, lymphopenia in 26 (60.47％) patients, and monocytosis in 7 (16.28％) patients. Besides, 40 (93.02％) patients had bilateral patchy nodular or interstitial infiltration on chest X-ray. The primary outcomes occurred in 20 patients (46.5％), among whom 8 required mechanical ventilation. The patients who had met the primary outcomes were older. They were prone to have at least 1 comorbidity (P=0.004), diabetes (P=0.01), hypertension, higher sequential organ failure assessment score, more tachycardia, lower SpO2, lower PaO2/FiO2, more thrombocytopenia, and more pancytopenia. Conclusions: This retrospective study identified several risk factors for poor outcomes in adults with COVID-19. In particular, older age, tachycardia, high SOFA score, low SpO2, low PaO2/FiO2, presence of comorbidities in form of diabetes and hypertension, thrombocytopenia, and pancytopenia at admission were associated with higher odds of ICU admission, a requirement of mechanical ventilation and in-hospital death.     

Modified guanidinium thiocyanate method for human sperm DNA isolation

Mammalian sperm chromatin is highly condensed, so isolating DNA from such chromatin can be a formidable task. The procedures that produce high quality DNA from somatic cells fail to yield quality sperm DNA. In this study we have modified the previously used guanidinium method to make it simple and efficient in isolating human sperm DNA. In our method, the lysis buffer contained guanidinium, sodium citrate, sarkosyl, proteinase K and mercaptoethanol. Proteinase K was not used in the original guanidinium method but was included in our protocol. CsCl centrifugation of the lysate, as described in the original procedure, was omitted. Instead, isopropyl alcohol was added directly to the lysis buffer to harvest the DNA. This modified guanidinium method generated high molecular weight DNA while the other two methods resulted in considerable DNA degradation. There was no difficulty in restriction enzyme digestion of DNA prepared by the modified method as revealed by Southern blot analysis. Since the modified guanidinium method is a simple one-step procedure which avoids homogenization, organic solvents, centrifugation and, more importantly, produces degradation-free DNA, it could be the method of choice when DNA from mature germ cells is needed.      

Thymus dysfunction and chronic inflammatory disease in gp39 transgenic mice

Expression of gp39 on activated T cells provides a co-stimulatory signal in peripheral lymphoid tissue that regulates humoral and cell- mediated immunity. The function of gp39 and its receptor CD40 in thymus remains uncertain. Here we report that overexpression of gp39 in transgenic mouse thymus caused a dose-dependent decline in thymocyte numbers (> 500 fold), loss of cortical epithelium and expansion of CD40+ medullary cells. Transplantation of transgenic bone marrow into normal mice indicated that gp39 significantly diminished thymocyte viability in the context of a 'normal' thymic environment. The peripheral tissues of transgenic mice also accumulated abnormalities in a transgene dose-dependent manner that involved inflammation and lymphoid tissue hypertrophy. Animals with the highest transgene copy numbers acquired a lethal inflammatory bowel disease marked by the infiltration of gp39+ T cells and CD40+ cells into diseased tissues. Examination of cells overexpressing gp39 suggested that these defects were caused, in part, by the saturation of a mechanism that sequesters gp39 inside non-activated cells and thus protects the immune system from inappropriate gp39-CD40 interaction. These results establish a regulatory role for gp39 in thymus function and a causal relationship in mediating chronic inflammatory disease.