The impact of interindividual variation in NAT2 activity on benzidine urinary metabolites and urothelial DNA adducts in exposed workers.

Several epidemiologic studies indicate that NAT2-related slow N-acetylation increases bladder cancer risk among workers exposed to aromatic amines, presumably because N-acetylation is important for the detoxification of these compounds. Previously, we showed that NAT2 polymorphisms did not influence bladder cancer risk among Chinese workers exposed exclusively to benzidine (BZ), suggesting that NAT2 N-acetylation is not a critical detoxifying pathway for this aromatic amine. To evaluate the biologic plausibility of this finding, we carried out a cross-sectional study of 33 workers exposed to BZ and 15 unexposed controls in Ahmedabad, India, to evaluate the presence of BZ-related DNA adducts in exfoliated urothelial cells, the excretion pattern of BZ metabolites, and the impact of NAT2 activity on these outcomes. Four DNA adducts were significantly elevated in exposed workers compared to controls; of these, the predominant adduct cochromatographed with a synthetic N-(3'- phosphodeoxyguanosin-8-yl)-N'-acetylbenzidine standard and was the only adduct that was significantly associated with total BZ urinary metabolites (r = 0.68, P < 0.0001). To our knowledge this is the first report to show that BZ forms DNA adducts in exfoliated urothelial cells of exposed humans and that the predominant adduct formed is N-acetylated, supporting the concept that monofunctional acetylation is an activation, rather than a detoxification, step for BZ. However, because almost all BZ-related metabolites measured in the urine of exposed workers were acetylated among slow, as well as rapid, acetylators (mean +/- SD 95 +/- 1.9% vs. 97 +/- 1.6%, respectively) and NAT2 activity did not affect the levels of any DNA adduct measured, it is unlikely that interindividual variation in NAT2 function is relevant for BZ-associated bladder carcinogenesis.     

Heterogeneous phenotypes of platelet and plasma von Willebrand factor in obligatory heterozygotes for severe von Willebrand disease

To characterize the heterogeneity of severe (type III) von Willebrand disease (vWD), plasma and platelet von Willebrand factor antigen (vWF:Ag) and ristocetin cofactor activity (Ricof) were measured in 28 obligatory heterozygotes (ie, parents or children of probands from 15 different kindreds with severe vWD). On the average, heterozygotes had low levels of vWF in both platelets and plasma. There was, however, considerable heterogeneity, with four distinct patterns. Eleven heterozygotes had concordant reduction of vWF:Ag and Ricof in both plasma and platelets; five had low levels of vWF:Ag and Ricof in plasma contrasting with normal levels in platelets; eight had a peculiar pattern, the reverse of the above (ie, low levels in platelets and normal levels in plasma); and in one, both vWF measurements were normal in plasma and platelets. These patterns were genetically determined: they were consistent in four couples of consanguineous heterozygotes and in two couples carrying the same gene deletion. Only the remaining three heterozygotes had no clearly identifiable pattern. Other findings of this study were that although most of the heterozygotes had normal bleeding times, the 7 of 28 who had prolonged bleeding times had concordantly low levels of vWF measurements in both plasma and platelets. In conclusion, this large series of obligatory heterozygotes provides evidence for phenotypic and genotypic heterogeneity of severe vWD.     

Hemophilia A: role of FVIIIC/vWF Ag in assisting linkage analysis for carrier detection.

Carrier detection for hemophilia A was carried out in 52 females from 30 families presenting to the Haematology Department AIIMS, using linkage analysis and factor VIIIC (FVIIIC)-von Willebrand factor (vWF) antigen assay. The allelic frequency for the marker Bcl 1 and Xba 1 was 0.58 and 0.54, respectively, for the positive alleles and 0.42 and 0.46, respectively, for the negative alleles. The heterozygosity frequency of Bcl I and Xba 1 was 0.65 and 0.55, respectively. Of the 52 females, 30 were mothers of hemophilic patients and 22 were sisters of hemophilic patients. Of the 30 mothers, positive family history was present in 14. In these patients, the defective X chromosome was tracked in 10, and in four the defective X chromosome could not be tracked because the mothers were homozygous for the marker used. Of the 16 mothers without a family history of disease, three were observed to be carriers based on linkage analysis and reduced factor VIII levels in mother/sister. Possible defective X chromosome was tracked in 11 mothers and five were noninformative because they did not show heterozygosity for the markers used. Using linkage analysis, nine of the 22 sisters were found to be definite carriers, 10 noncarriers, and three were noninformative. It is thus concluded that using Bcl 1 and Xba 1 linkage analysis, carrier status can be definitely ascertained in 50% females and this level of information can be increased to 61.5% by measuring FVIIIC/vWF antigen levels in them.     

Clinico-immunological profile in a case of hepatic tubercular abscess: A rare manifestation of extrapulmonary TB in an immunocompetent child

Tubercular liver abscess is a rare entity even in an endemic area for TB. We report here a rare case of pediatric tuberculous liver abscess, the etiology of which was established using recently introduced Cartridge based nucleic acid amplification test (CBNAAT). A 7 years old male child presented with vomiting, pain abdomen and fever. Hepatomegaly was found on examination. Ultrasound of abdomen revealed two liver abscesses in the right lobe. Patient remained symptomatic even after empirical antimicrobial therapy. On diagnostic tap Gram stained smear of the pus showed polymorphs with negative culture. CBNAAT was positive for Mycobacterial tuberculosis and sensitive to rifampicin. Subjecting difficult extrapulmonary specimens to relevant microbiological investigations along with CBNAAT and other newer methods may improve diagnosis of tuberculosis in such rare cases thus leading to an early management and decrease in morbidity.     

Modelling the time course of antimalarial parasite killing: a tour of animal and human models,translation and challenges

Malaria remains a global public health concern and current treatment options are suboptimal in some clinical settings. For effective chemotherapy, antimalarial drug concentrations must be sufficient to remove completely all of the parasites in the infected host. Optimized dosing therefore requires a detailed understanding of the time course of antimalarial response, whilst simultaneously considering the parasite life cycle and host immune elimination. Recently, the World Health Organization (WHO) has recommended the development of mathematical models for understanding better antimalarial drug resistance and management. Other international groups have also suggested that mechanistic pharmacokinetic (PK) and pharmacodynamic (PD) models can support the rationalization of antimalarial dosing strategies. At present, artemisinin-based combination therapy (ACT) is recommended as first line treatment of falciparum malaria for all patient groups. This review summarizes the PK–PD characterization of artemisinin derivatives and other partner drugs from both preclinical studies and human clinical trials. We outline the continuous and discrete time models that have been proposed to describe antimalarial activity on specific stages of the parasite life cycle. The translation of PK–PD predictions from animals to humans is considered, because preclinical studies can provide rich data for detailed mechanism-based modelling. While similar sampling techniques are limited in clinical studies, PK–PD models can be used to optimize the design of experiments to improve estimation of the parameters of interest. Ultimately, we propose that fully developed mechanistic models can simulate and rationalize ACT or other treatment strategies in antimalarial chemotherapy.     

Artificial intelligence in gastroenterology: A state-of-the-art review

The development of artificial intelligence (AI) has increased dramatically in the last 20 years, with clinical applications progressively being explored for most of the medical specialties. The field of gastroenterology and hepatology, substantially reliant on vast amounts of imaging studies, is not an exception. The clinical applications of AI systems in this field include the identification of premalignant or malignant lesions (e.g., identification of dysplasia or esophageal adenocarcinoma in Barrett’s esophagus, pancreatic malignancies), detection of lesions (e.g., polyp identification and classification, small-bowel bleeding lesion on capsule endoscopy, pancreatic cystic lesions), development of objective scoring systems for risk stratification, predicting disease prognosis or treatment response [e.g., determining survival in patients post-resection of hepatocellular carcinoma), determining which patients with inflammatory bowel disease (IBD) will benefit from biologic therapy], or evaluation of metrics such as bowel preparation score or quality of endoscopic examination. The objective of this comprehensive review is to analyze the available AI-related studies pertaining to the entirety of the gastrointestinal tract, including the upper, middle and lower tracts; IBD; the hepatobiliary system; and the pancreas, discussing the findings and clinical applications, as well as outlining the current limitations and future directions in this field.     

Albumin inhibits apolipoprotein AI and AII production in human hepatoblastoma cell line (Hep G2): additive effects of oleate-albumin complex

Although the role of multiple humoral agents (such as plasma albumin, glucose, hormones etc.) are implicated in lipoprotein metabolism, the mechanism of action of these agents on various steps of the synthesis and secretion of lipoproteins and apolipoproteins (protein moieties of lipoproteins) are not completely understood. Specifically, the hepatocellular mechanisms of the effect of albumin and fatty acids on apolipoprotein (apo) AI and AII [major proteins of high density lipoproteins (HDL)] synthesis and secretion are not known. Using human hepatoblastoma cells (Hep G2) as an in vitro model system, this study examined the effect of albumin and fatty acids on the synthesis, secretion, and the steady-state mRNA expression of apo AI and AII. The data indicated that the incubation of Hep G2 cells with albumin, dose-dependently, inhibited apo AI and AII accumulation (secretion) in the media, de novo synthesis, and the steady-state mRNA expression. Albumin did not alter total protein synthesis; thus the effect of albumin appeared to be specific for the synthesis and secretion of apo AI and apo AII. Free fatty acids (FFA) are transported by albumin and diseases characterized by enhanced FFA mobilization (e.g. diabetes mellitus) are associated with low HDL levels. Studies were therefore performed to examine the effect of albumin-bound-oleic acid on apo AI and apo AII production. The results showed that the albumin-oleate complex further increased the inhibitory effects of albumin on apo AI and apo AII production. These data suggest how HDL metabolism may be affected at the hepatocellular level by alterations in plasma albumin concentrations and/or fatty acid mobilization in clinical situations characterized by altered HDL levels.     

Type 2 Diabetes and COVID-19–Related Mortality in the Critical Care Setting: A National Cohort Study in England,March–July 2020

OBJECTIVETo describe the relationship between type 2 diabetes and all-cause mortality among adults with coronavirus disease 2019 (COVID-19) in the critical care setting.RESEARCH DESIGN AND METHODSThis was a nationwide retrospective cohort study in people admitted to hospital in England with COVID-19 requiring admission to a high dependency unit (HDU) or intensive care unit (ICU) between 1 March 2020 and 27 July 2020. Cox proportional hazards models were used to estimate 30-day in-hospital all-cause mortality associated with type 2 diabetes, with adjustment for age, sex, ethnicity, obesity, and other major comorbidities (chronic respiratory disease, asthma, chronic heart disease, hypertension, immunosuppression, chronic neurological disease, chronic renal disease, and chronic liver disease).RESULTSA total of 19,256 COVID-19–related HDU and ICU admissions were included in the primary analysis, including 13,809 HDU (mean age 70 years) and 5,447 ICU (mean age 58 years) admissions. Of those admitted, 3,524 (18.3%) had type 2 diabetes and 5,077 (26.4%) died during the study period. Patients with type 2 diabetes were at increased risk of death (adjusted hazard ratio [aHR] 1.23 [95% CI 1.14, 1.32]), and this result was consistent in HDU and ICU subsets. The relative mortality risk associated with type 2 diabetes decreased with higher age (age 18–49 years aHR 1.50 [95% CI 1.05, 2.15], age 50–64 years 1.29 [1.10, 1.51], and age ≥65 years 1.18 [1.09, 1.29]; P value for age–type 2 diabetes interaction = 0.002).CONCLUSIONSType 2 diabetes may be an independent prognostic factor for survival in people with severe COVID-19 requiring critical care treatment, and in this setting the risk increase associated with type 2 diabetes is greatest in younger people.