Total peripheral resistance responsiveness during the development of secondary renal hypertension in dogs

OBJECTIVE: To determine whether the responses of total peripheral resistance and arterial pressure to vasoconstrictor agents are amplified as renovascular hypertension develops in dogs. METHODS: After baseline measurements, the effects of renal artery stenosis (1K, 1C hypertension) were studied in groups of untreated and enalapril-treated dogs early (1-3 weeks) and later (4-6 weeks) as the hypertension developed. Both resting and open-loop haemodynamic measurements were made and the effects of acute intravenous infusions of vasopressin (0.25, 0.5 and 1.25 ng/kg per min) and phenylephrine (0.125, 0.25 and 0.50 microg/kg per min on arterial pressure, cardiac output and calculated total peripheral resistance responses were measured. RESULTS: Renal artery stenosis induced an increase in arterial blood pressure in both groups of dogs, with similar changes in haemodynamics also observed in open-loop conditions. The slopes of arterial pressure and peripheral resistance responses to vasopressin and phenylephrine were not significantly changed in early or late hypertension, in either the untreated or enalapril-treated groups. CONCLUSIONS: Hypertension from renal artery stenosis in dogs was due to nonautonomic, nonangiotensin II mechanisms. There was no evidence of vascular amplification of the effects of vasoconstrictor agents, indicating that this did not play a role in the development of hypertension.     

Optimization of Dengue-3 recombinant NS1 protein expression in E. coli and in vitro refolding for diagnostic applications

Dengue non-structural protein (NS1) is known to be protective antigen and also has immense application for serodiagnosis. Several serodiagnostic assays available for dengue viral infection are dependent on tissue culture-grown viral proteins. This task is unsafe, laborious, more expensive that makes it unsuitable for routine large-scale production. Although bacterial expression is relatively simple and easy for recombinant protein expression, it is more challenging to make NS1 protein with native structural and immunological features using bacterial expression system. We have successfully developed a method leading to the purification and refolding of recombinant dengue virus type 3 (DENV3) NS1. The gene encoding NS1 was amplified and cloned in pET28a (+) vector. In order to increase the purity of the recombinant NS1, the transgene was engineered to carry 6× Histidine tags at both N and C-terminal ends. The recombinant construct (pETNS1) was transformed into E. coli Rosetta-gami cells and the expression conditions viz IPTG concentration, media type, temperature, and harvest time were optimized. The size of the expressed protein was found to be ~45 kDa and the authenticity of the expressed protein was confirmed using anti-His and anti-NS1 monoclonal antibodies. The NS1 protein was purified under denaturing conditions, to attain the native conformation, NS1 protein was in vitro refolded and dialyzed. The refolded NS1 protein was detected by commercial Immuno chromatographic strip and NS1 specific monoclonal antibodies. IgM antibody capture ELISA was performed using refolded recombinant NS1 protein which recognized the IgM antibodies in dengue-positive samples of acute phase of infection. Our result suggests that rNS1 protein has immense diagnostic potential and can be used in developing point of care diagnostic assays.     

Mutations in the NHLRC1 gene are the common cause for Lafora disease in the Japanese population

Lafora disease (LD) is a rare autosomal recessive genetic disorder characterized by epilepsy, myoclonus, and progressive neurological deterioration. LD is caused by mutations in the EMP2A gene encoding a protein phosphatase. A second gene for LD, termed NHLRC1 and encoding a putative E3 ubiquitin ligase, was recently identified on chromosome 6p22. The LD is relatively common in southern Europe, the Middle East, and Southeast Asia. A few sporadic cases with typical LD phenotype have been reported from Japan; however, our earlier study failed to find EPM2A mutations in four Japanese families with LD. We recruited four new families from Japan and searched for mutations in EPM2A . All eight families were also screened for NHLRC1 mutations. We found five independent families having novel mutations in NHLRC1. Identified mutations include five missense mutations (p.I153M, p.C160R, p.W219R, p.D245N, and p.R253K) and a deletion mutation (c.897insA; p.S299fs13). We also found a family with a ten base pair deletion (c.822-832del10) in the coding region of EPM2A. In two families, no EPM2A or NHLRC1 mutation was found. Our study, in addition to documenting the genetic and molecular heterogeneity observed for LD, suggests that mutations in the NHLRC1 gene may be a common cause of LD in the Japanese population.     

MIO-M1 cells and similar muller glial cell lines derived from adult human retina exhibit neural stem cell characteristics

Growing evidence suggests that glial cells may have a role as neural precursors in the adult central nervous system. Although it has been shown that Müller cells exhibit progenitor characteristics in the postnatal chick and rat retinae, their progenitor-like role in developed human retina is unknown. We first reported the Müller glial characteristics of the spontaneously immortalized human cell line MIO-M1, but recently we have derived similar cell lines from the neural retina of several adult eye donors. Since immortalization is one of the main properties of stem cells, we investigated whether these cells expressed stem cell markers. Cells were grown as adherent monolayers, responded to epidermal growth factor, and could be expanded indefinitely without growth factors under normal culture conditions. They could be frozen and thawed without losing their characteristics. In the presence of extracellular matrix and fibroblast growth factor-2 or retinoic acid, they acquired neural morphology, formed neurospheres, and expressed neural stem cell markers including betaIII tubulin, Sox2, Pax6, Chx10, and Notch 1. They also expressed markers of postmitotic retinal neurons, including peripherin, recoverin, calretinin, S-opsin, and Brn3. When grafted into the subretinal space of dystrophic Royal College of Surgeons rats or neonatal Lister hooded rats, immortalized cells migrated into the retina, where they expressed various markers of retinal neurons. These observations indicate that adult human neural retina harbors a population of cells that express both Müller glial and stem cell markers and suggest that these cells may have potential use for cell-based therapies to restore retinal function. Disclosure of potential conflicts of interest is found at the end of this article.     

Controlled release of anti-diabetic drug Gliclazide from poly(caprolactone)/poly(acrylic acid) hydrogels

Drug Gliclazide (Glz) has limited solubility and low bioavailability. In order to obtain a controlled release of this drug and to improve its bioavailability, the drug has been loaded into poly(caprolactone) (PCL)/poly(acrylic acid) (PAAc) hydrogels, prepared by free radical polymerization of acrylic acid in the presence of poly(caprolactone) in acetone medium using azo-isobutyronitrile as initiator and N,N′ methylene bisacrylamide as cross-linking agent. The swelling behaviour of these hydrogels has been investigated in the physiological gastric and intestinal fluids to obtain an optimum composition suitable for delivery of a biologically active compound. The gels were loaded with anti-diabetic drug Glz and a detailed investigation of release of drug has been carried out. Various kinetic models have been applied on the release data. Finally, the Albino wistar rats were treated for Streptozotocin plus nicotinamide – induced diabetes using a Glz-loaded PCL/PAAc hydrogel. The results indicated a fair reduction in the glucose level of rats.     

Association between antecedent statin use and severe disease outcomes in COVID-19: A retrospective study with propensity score matching

BackgroundStatins have been associated with a reduction in inflammatory markers and improved endothelial function. Whether statins offer any benefit in COVID-19 needs to be elucidated.ObjectiveTo determine the association between antecedent statin use and severe disease outcomes among COVID-19 patients.MethodsA retrospective cohort study on 1014 patients with confirmed COVID-19 diagnosis. Outcomes were mortality, need for mechanical ventilation, and intensive care admission. Patients were classified into statin-users vs statin non-users based on antecedent use of statins. Multivariable regression analysis was performed adjusting for confounders such as age, sex, race, BMI, smoking, insurance, and comorbidities. Propensity score matching was performed to achieve a 1:1 balanced cohort.ResultsA total of 1014 patients (Median age 65 (IQR 53–73); 530 (52.3%) males; 753 (74.3%) African Americans; median BMI 29.4 (IQR 25.1–35.9); 615 (60.7%) with Medicare insurance) were included in the study. About 454 patients (44.77%) were using statins as home medication. Antecedent statin use was associated with significant decrease in mortality in the total cohort (OR, 0.66; 95% CI, 0.46 – 0.95; p = 0.03). Among the propensity score matched (PSM) cohort of 466 patients (233 statin users and 233 statin non-users), all the baseline characteristics had similar distribution among the two groups. Statin users had significant reduction in mortality in the PSM cohort as well (OR, 0.56; 95% CI, 0.37 – 0.83; p = 0.004).ConclusionsStatin use was associated with significant reduction in mortality among COVID-19 patients. These findings support the pursuit of randomized clinical trials to explore the possible benefits of statins in COVID-19.     

Primary intraosseous myoepithelioma arising in the iliac bone and displaying trisomies of 11, 15, 17 with del (16q) and del (22q11)--A rare case report with review of literature

Mixed tumors are uncommonly observed in the musculoskeletal system, where they form a common spectrum with a myoepithelioma and a parachordoma. Herein, we present a rare case of a mixed tumor/myoepithelioma arising in the iliac bone of a young adult male who presented with swelling in his right hip. Radiological imaging disclosed a large, intraosseous, lytic, heterogenous mass with a soft tissue component. Biopsy and subsequent tumor resection showed an 18 cm sized tumor involving the iliac bone and soft tissues and comprising polygonal and spindly cells, arranged in cords and aggregates, embedded in a myxohyaline stroma with osteochondroid differentiation. Tumor cells exhibited mild nuclear variation, rare mitotic figures, focal cytoplasmic clearing, and prominent squamous differentiation. On immunohistochemistry (IHC), tumor cells were diffusely positive for S100-P, EMA, CK5/6, p63, GFAP, calponin, and focally positive for CK/MNF116, but negative for Brachyury/T. Diagnosis of a myoepithelioma/mixed tumor was offered. Further, cytogenetic analysis revealed lack of EWSR1 gene rearrangement and showed clonal trisomies of 11, 15, 17 with del (16q) and del (22q11). The present case is a rare documentation of a myoepithelioma in the appendicular bones and the second such case identified in the iliac bone. IHC and cytogenetic findings supported a myoepithelial cell origin, and reinforced its relationship with a parachordoma and its distinction from mixed salivary gland tumors, a chordoma, and an extraskeletal myxoid chondrosarcoma that form its differential diagnoses.     

Cytogenetic pattern profiling in cases of Acute Lymphoblastic Leukemia in pediatric age group

Introduction

Acute lymphoblastic leukemia (ALL) comprises about 70–80% of childhood leukemia. The present work was undertaken to study the spectrum of chromosomal abnormalities in North Indian population in haematologically confirmed pediatric ALL patients using bone marrow aspirates.