Population-scale skeletal muscle single-nucleus multi-omic profiling reveals extensive context specific genetic regulation

Skeletal muscle, the largest human organ by weight, is relevant to several polygenic metabolic traits and diseases including type 2 diabetes (T2D). Identifying genetic mechanisms underlying these traits requires pinpointing the relevant cell types, regulatory elements, target genes, and causal variants. Here, we used genetic multiplexing to generate population-scale single nucleus (sn) chromatin accessibility (snATAC-seq) and transcriptome (snRNA-seq) maps across 287 frozen human skeletal muscle biopsies representing 456,880 nuclei. We identified 13 cell types that collectively represented 983,155 ATAC summits. We integrated genetic variation to discover 6,866 expression quantitative trait loci (eQTL) and 100,928 chromatin accessibility QTL (caQTL) (5% FDR) across the five most abundant cell types, cataloging caQTL peaks that atlas-level snATAC maps often miss. We identified 1,973 eGenes colocalized with caQTL and used mediation analyses to construct causal directional maps for chromatin accessibility and gene expression. 3,378 genome-wide association study (GWAS) signals across 43 relevant traits colocalized with sn-e/caQTL, 52% in a cell-specific manner. 77% of GWAS signals colocalized with caQTL and not eQTL, highlighting the critical importance of population-scale chromatin profiling for GWAS functional studies. GWAS-caQTL colocalization showed distinct cell-specific regulatory paradigms. For example, a C2CD4A/B T2D GWAS signal colocalized with caQTL in muscle fibers and multiple chromatin loop models nominated VPS13C, a glucose uptake gene. Sequence of the caQTL peak overlapping caSNP rs7163757 showed allelic regulatory activity differences in a human myocyte cell line massively parallel reporter assay. These results illuminate the genetic regulatory architecture of human skeletal muscle at high-resolution epigenomic, transcriptomic, and cell state scales and serve as a template for population-scale multi-omic mapping in complex tissues and traits.

Using a modular massively parallel reporter assay to discover context-specific regulatory grammars in type 2 diabetes

Recent genome-wide association studies have established that most complex disease-associated loci are found in noncoding regions where defining their function is nontrivial. In this study, we leverage a modular massively parallel reporter assay (MPRA) to uncover sequence features linked to context-specific regulatory activity. We screened enhancer activity across a panel of 198-bp fragments spanning over 10k type 2 diabetes- and metabolic trait-associated variants in the 832/13 rat insulinoma cell line, a relevant model of pancreatic beta cells. We explored these fragments' context sensitivity by comparing their activities when placed up-or downstream of a reporter gene, and in combination with either a synthetic housekeeping promoter (SCP1) or a more biologically relevant promoter corresponding to the human insulin gene ( INS ). We identified clear effects of MPRA construct design on measured fragment enhancer activity. Specifically, a subset of fragments (n = 702/11,656) displayed positional bias, evenly distributed across up- and downstream preference. A separate set of fragments exhibited promoter bias (n = 698/11,656), mostly towards the cell-specific INS promoter (73.4%). To identify sequence features associated with promoter preference, we used Lasso regression with 562 genomic annotations and discovered that fragments with INS promoter-biased activity are enriched for HNF1 motifs. HNF1 family transcription factors are key regulators of glucose metabolism disrupted in maturity onset diabetes of the young (MODY), suggesting genetic convergence between rare coding variants that cause MODY and common T2D-associated regulatory variants. We designed a follow-up MPRA containing HNF1 motif-enriched fragments and observed several instances where deletion or mutation of HNF1 motifs disrupted the INS promoter-biased enhancer activity, specifically in the beta cell model but not in a skeletal muscle cell line, another diabetes-relevant cell type. Together, our study suggests that cell-specific regulatory activity is partially influenced by enhancer-promoter compatibility and indicates that careful attention should be paid when designing MPRA libraries to capture context-specific regulatory processes at disease-associated genetic signals.

A Locus on Chromosome 15 Contributes to Acute Ozone-Induced Lung Injury in Collaborative Cross Mice

Ozone (O3)-induced respiratory toxicity varies considerably within the human population and across inbred mouse strains, indicative of gene-environment interactions (GxE). Though previous studies have identified several quantitative trait loci (QTL) and candidate genes underlying responses to O3 exposure, precise mechanisms of susceptibility remain incompletely described. We sought to update our understanding of the genetic architecture of O3 responsiveness using the Collaborative Cross (CC) recombinant inbred mouse panel. We evaluated hallmark O3-induced inflammation and injury phenotypes in 56 CC strains after exposure to filtered air or 2 ppm O3, and performed focused genetic analysis of variation in lung injury, as reflected by protein in lung lavage fluid. Strain-dependent responses to O3 were clear, and QTL mapping revealed two novel loci on Chromosomes 10 (peak: 26.2 Mb; 80% CI: 24.6-43.6 Mb) and 15 (peak: 47.1 Mb; 80% CI: 40.2-54.9 Mb), the latter surpassing the 95% significance threshold. At the Chr. 15 locus, C57BL/6J and CAST/EiJ founder haplotypes were associated with higher lung injury responses compared to all other CC founder haplotypes. With further statistical analysis and a weight of evidence approach, we delimited the Chr. 15 QTL to a ~2 Mb region containing 21 genes (10 protein coding) and nominated three candidate genes, namely Oxr1, Rspo2, and Angpt1. Gene and protein expression data further supported Oxr1 and Angpt1 as priority candidate genes. In summary, we have shown that O3-induced lung injury is modulated by genetic variation, identified two high priority candidate genes, and demonstrated the value of the CC for detecting GxE.

Integrative analysis reveals mouse strain-dependent responses to acute ozone exposure associated with airway macrophage transcriptional activity

Acute ozone (O3) exposure is associated with multiple adverse cardiorespiratory outcomes, the severity of which varies across individuals in human populations and inbred mouse strains. However, molecular determinants of response, including susceptibility biomarkers that distinguish who will develop severe injury and inflammation, are not well characterized. We and others have demonstrated that airway macrophages (AMs) are an important resident immune cell type that are functionally and transcriptionally responsive to O3 inhalation. Here, we sought to explore influences of strain, exposure, and strain-by-O3 exposure interactions on AM gene expression and identify transcriptional correlates of O3-induced inflammation and injury across six mouse strains, including five Collaborative Cross (CC) strains. We exposed adult mice of both sexes to filtered air (FA) or 2 ppm O3 for 3 h and measured inflammatory and injury parameters 21 h later. Mice exposed to O3 developed airway neutrophilia and lung injury with strain-dependent severity. In AMs, we identified a common core O3 transcriptional response signature across all strains, as well as a set of genes exhibiting strain-by-O3 exposure interactions. In particular, a prominent gene expression contrast emerged between a low- (CC017/Unc) and high-responding (CC003/Unc) strain, as reflected by cellular inflammation and injury. Further inspection indicated that differences in their baseline gene expression and chromatin accessibility profiles likely contribute to their divergent post-O3 exposure transcriptional responses. Together, these results suggest that aspects of O3-induced respiratory responses are mediated through altered AM transcriptional signatures and further confirm the importance of gene-environment interactions in mediating differential responsiveness to environmental agents.

Ozone-induced changes in the murine lung extracellular vesicle small RNA landscape

Inhalation exposure to ozone (O3 ) causes adverse respiratory health effects that result from airway inflammation, a complex response mediated in part by changes to airway cellular transcriptional programs. These programs may be regulated by microRNAs transferred between cells (e.g., epithelial cells and macrophages) via extracellular vesicles (EV miRNA). To explore this, we exposed female C57BL/6J mice to filtered air (FA), 1, or 2 ppm O3 by inhalation and collected bronchoalveolar lavage fluid (BALF) 21 h later for markers of airway inflammation, EVs, and EV miRNA. Both concentrations of O3  significantly increased markers of inflammation (neutrophils), injury (total protein), and the number of EV-sized particles in the BALF. Imagestream analysis indicated a substantial portion of particles was positive for canonical EV markers (CD81, CD51), and Siglec-F, a marker of alveolar macrophages. Using high-throughput small RNA sequencing, we identified several differentially expressed (DE) BALF EV miRNAs after 1 ppm (16 DE miRNAs) and 2 ppm (99 DE miRNAs) O3 versus FA exposure. O3 concentration-response patterns in EV miRNA expression were apparent, particularly for miR-2137, miR-126-3p, and miR-351-5p. Integrative analysis of EV miRNA expression and airway cellular mRNA expression identified EV miR-22-3p as a candidate regulator of transcriptomic responses to O3 in airway macrophages. In contrast, we did not identify candidate miRNA regulators of mRNA expression data from conducting airways (predominantly composed of epithelial cells). In summary, our data show that O3 exposure alters EV release and EV miRNA expression, suggesting that further investigation of EVs may provide insight into their effects on airway macrophage function and other mechanisms of O3 -induced respiratory inflammation.

Baseline and innate immune response characterization of a Zfp30 knockout mouse strain

Airway neutrophilia is correlated with disease severity in a number of chronic and acute pulmonary diseases, and dysregulation of neutrophil chemotaxis can lead to host tissue damage. The gene Zfp30 was previously identified as a candidate regulator of neutrophil recruitment to the lungs and secretion of CXCL1, a potent neutrophil chemokine, in a genome-wide mapping study using the Collaborative Cross. ZFP30 is a putative transcriptional repressor with a KRAB domain capable of inducing heterochromatin formation. Using a CRISPR-mediated knockout mouse model, we investigated the role that Zfp30 plays in recruitment of neutrophils to the lung using models of allergic airway disease and acute lung injury. We found that the Zfp30 null allele did not affect CXCL1 secretion or neutrophil recruitment to the lungs in response to various innate immune stimuli. Intriguingly, despite the lack of neutrophil phenotype, we found there was a significant reduction in the proportion of live Zfp30 homozygous female mutant mice produced from heterozygous matings. This deviation from the expected Mendelian ratios implicates Zfp30 in fertility or embryonic development. Overall, our results indicate that Zfp30 is an essential gene but does not influence neutrophilic inflammation in this particular knockout model.

Transcriptional Profiling of the Murine Airway Response to Acute Ozone Exposure

Ambient ozone (O3) exposure has serious consequences on respiratory health, including airway inflammation and injury. Decades of research have yielded thorough descriptions of these outcomes; however, less is known about the molecular processes that drive them. The aim of this study was to further describe the cellular and molecular responses to O3 exposure in murine airways, with a particular focus on transcriptional responses in 2 critical pulmonary tissue compartments: conducting airways (CA) and airway macrophages (AM). After exposing adult, female C57BL/6J mice to filtered air, 1 or 2 ppm O3, we assessed hallmark responses including airway inflammation (cell counts and cytokine secretion) and injury (epithelial permeability), followed by gene expression profiling of CA and AM by RNA-seq. As expected, we observed concentration-dependent increases in airway inflammation and injury. Conducting airways and AM both exhibited changes in gene expression to both 1 and 2 ppm O3 that were largely compartment-specific. In CA, genes associated with epithelial barrier function, detoxification processes, and cellular proliferation were altered, while O3 affected genes involved in innate immune signaling, cytokine production, and extracellular matrix remodeling in AM. Further, CA and AM also exhibited notable differences in concentration-response expression patterns for large numbers of genes. Overall, our study has described transcriptional responses to acute O3 exposure, revealing both shared and unique gene expression patterns across multiple concentrations of O3 and in 2 important O3-responsive tissues. These profiles provide broad mechanistic insight into pulmonary O3 toxicity, and reveal a variety of targets for focused follow-up studies.

Molecular classification of Crohn's disease reveals two clinically relevant subtypes

OBJECTIVE

The clinical presentation and course of Crohn's disease (CD) is highly variable. We sought to better understand the cellular and molecular mechanisms that guide this heterogeneity, and characterise the cellular processes associated with disease phenotypes.

DESIGN

We examined both gene expression and gene regulation (chromatin accessibility) in non-inflamed colon tissue from a cohort of adult patients with CD and control patients. To support the generality of our findings, we analysed previously published expression data from a large cohort of treatment-naïve paediatric CD and control ileum.

RESULTS

We found that adult patients with CD clearly segregated into two classes based on colon tissue gene expression-one that largely resembled the normal colon and one where certain genes showed expression patterns normally specific to the ileum. These classes were supported by changes in gene regulatory profiles observed at the level of chromatin accessibility, reflective of a fundamental shift in underlying molecular phenotypes. Furthermore, gene expression from the ilea of a treatment-naïve cohort of paediatric patients with CD could be similarly subdivided into colon-like and ileum-like classes. Finally, expression patterns within these CD subclasses highlight large-scale differences in the immune response and aspects of cellular metabolism, and were associated with multiple clinical phenotypes describing disease behaviour, including rectal disease and need for colectomy.

CONCLUSIONS

Our results strongly suggest that these molecular signatures define two clinically relevant forms of CD irrespective of tissue sampling location, patient age or treatment status.

Predictive value of serum globulin levels for the extent of hepatic fibrosis in patients with chronic hepatitis B infection

The mechanism underlying disease progression in hepatitis B virus (HBV) infection is unknown. Immunoglobulins stimulate the proliferative activity of rat hepatic stellate cells in vitro. A strong association was found between serum immunoglobulin levels and hepatic fibrosis in patients with hepatitis C virus infection. Our objective was to determine if the same index could also be used in patients with chronic HBV infection. The records of 100 patients with biochemical, serological, virological and histological evidence of chronic HBV infection were reviewed for background factors and serum globulin and immunoglobulin levels. Mean (+/-SD) patient age was 44.0 +/- 14.7 years; 80 (80%) were male. Of the factors found to be significant on univariate analysis, the only significant predictors of severe hepatic fibrosis (stage > or = 2) on multivariate analysis were serum globulin level [odds ratio (OR) 5.97, 95% confidence intervals (CI) 1.82-19.53, P = 0.0004], platelet count (OR 0.98, CI 0.97-0.99, P = 0.001), and immunoglobulin G (IgG) level (OR 1.003, CI 1.000-1.007, P < 0.042) but not IgA, alkaline phosphatase, albumin or international normalized ratio. For each increase of 0.33 mg/dL in serum globulin, there was a 0.5 point increase in the stage of hepatic fibrosis. There appears to be a strong association between levels of serum globulin and IgG and extent of hepatic fibrosis in patients with chronic HBV infection. They can serve as noninvasive markers of hepatic fibrosis and, if confirmed, have important implications for the management of patients with chronic HBV infection.

An outbreak of adenovirus type 8 keratoconjunctivitis in a nursing home in Madrid

This work describes and analyses an outbreak of epidemic keratoconjunctivitis which occurred in 2001 and 2002 in a nursing home for the elderly in Leganes (an area of Madrid). This is the first such published case in Spain with these characteristics and this serotype identification. Sociodemographic characteristics, epidemic curve and attack rates are described. Comparisons of the data were carried out using a chi2 test for qualitative variable and t-test for quantitative. Factors associated with the illness are explored by means of contingency tables and logistic regression models. One hundred and two cases were detected, with an attack rate of 36.4% for residents, and 12.9% for workers, not considering spatial or professional differences. The epidemic curve showed an interpersonal transmission pattern. Multivariate analysis identified the following risk factors in the residents: able to wander freely through the building, urinary incontinence and use of shared bathroom. In 34.6% of the conjunctival samples, adenovirus serotype 8 was detected with identical genomic sequence. Establishment of hygienic sanitary guidance adapted for the cleaning of such establishments and contact with residents as well as early diagnosis and good coordination of human and material resources are key factors in the prevention and control of these outbreaks in closed communities.

Sick day management using blood 3-hydroxybutyrate (3-OHB) compared with urine ketone monitoring reduces hospital visits in young people with T1DM: a randomized clinical trial

AIMS

Diabetic ketoacidosis (DKA), a life-threatening acute complication of Type 1 diabetes, may be preventable with frequent monitoring of glycaemia and ketosis along with timely supplemental insulin. This prospective, two-centre study assessed sick day management using blood 3-hydroxybutyrate (3-OHB) monitoring compared with traditional urine ketone testing, aimed at averting emergency assessment and hospitalization.

METHODS

One hundred and twenty-three children, adolescents and young adults, aged 3-22 years, and their families received sick day education. Participants were randomized to receive either a blood glucose monitor that also measures blood 3-OHB (blood ketone group, n = 62) or a monitor plus urine ketone strips (urine ketone group, n = 61). All were encouraged to check glucose levels > or = 3 times daily and to check ketones during acute illness or stress, when glucose levels were consistently elevated (> or = 13.9 mmol/l on two consecutive readings), or when symptoms of DKA were present. Frequency of sick days, hyperglycaemia, ketosis, and hospitalization/emergency assessment were ascertained prospectively for 6 months.

RESULTS

There were 578 sick days during 21,548 days of follow-up. Participants in the blood ketone group checked ketones significantly more during sick days (276 of 304 episodes, 90.8%) than participants in the urine ketone group (168 of 274 episodes, 61.3%) (P < 0.001). The incidence of hospitalization/emergency assessment was significantly lower in the blood ketone group (38/100 patient-years) compared with the urine ketone group (75/100 patient-years) (P = 0.05).

CONCLUSIONS

Blood ketone monitoring during sick days appears acceptable to and preferred by young people with Type 1 diabetes. Routine implementation of blood 3-OHB monitoring for the management of sick days and impending DKA can potentially reduce hospitalization/emergency assessment compared with urine ketone testing and offers potential cost savings.

Mucormycosis of the renal allograft: case report and review of the literature

Fungal infection is an uncommon complication after renal transplantation. We describe a rare form of mucormycosis in the renal graft. Our method was to review chart data and to perform medline searches. The patient was a 42-year-old man who underwent living-unrelated kidney transplantation in Egypt and returned to Israel on POD 8. Within the ensuing 4 weeks he experienced acute rejection which responded to treatment with steroids. Few days after discharge he was readmitted because of fever and graft dysfunction. An infected large perigraft collection was drained, but the patient became anuric and septic. Kidney biopsy showed infarcted necrotic tissue infiltrated by fungi which grew Mucor species. Despite initial improvement following graft nephrectomy and antifungal treatment the patient died of sepsis. Literature review revealed only three additional cases of graft infection due to Mucorales. We conclude that Renal graft infection due to Mucorales is an extremely rare and potentially lethal complication. Living unrelated donation in third world countries might be a possible risk factor. Fungal colonization may occur during transplantation. A high index of suspicion, leading to early diagnosis and initiation of antifungal treatment, in addition to graft nephrectomy, are keys to a more favorable outcome.

Low flow veno-venous ECMO via subclavian dialysis catheter for severe respiratory failure

BACKGROUND

We present the case of a 12-year-old female with severe postoperative bacterial pneumonia unresponsive to conventional treatment following a failed renal transplant.

CASE REPORT

The patient was placed on low flow veno-venous extracorporeal membrane oxygenation (ECMO) as an adjuvant treatment to antibiotic therapy and maximal ventilatory support. Venous ECMO resulted in rapid improvement and the patient was successfully weaned after 48 hours of circulatory assistance. Two days later, the patient was extubated and safely discharged from the intensive care unit. Eighteen months later, she remains stable on peritoneal dialysis and is awaiting a new donor kidney.

CONCLUSIONS

Low flow veno-venous ECMO represents a new therapeutic alternative for critically ill patients whose condition does not meet the conventional ECMO criteria. Further clinical experience is still needed.

Antiandrogenic effect of RU-486 in the mouse kidney

RU-486 (mifepristone) is a synthetic steroid with potent antiprogesterone and antiglucocorticoid activity, that is currently used as a contraceptive agent. In the present work we have evaluated the antiandrogenic effect of this compound on mouse kidney, a very well known extragenital model of androgen action by studying the effect of RU-486 on renal parameters that depend on androgens, such as renal ornithine decarboxylase (ODC) activity and kidney hypertrophy, as well as the inhibitory action of mifepristone on the induction of renal ODC and kidney hypertrophy elicited by testosterone treatment in female mice and in castrated male. The results showed that: (1) 48 hr after treatment of male mice with of RU-486 (50 mg/kg, four injections) renal ODC activity decreased from 3.381 +/- 490 nmol CO2/h.g to 605 +/- 163 (SD, n = 5); (2) in female mice or orchidectomized male mice, RU-486 also inhibited the renal ODC induction elicited by exogenous administration of testosterone propionate (TP), the magnitude of the inhibition was dependent on the doses of TP and RU-486 used. While RU-486 at a dose of 25 mg/kg inhibited more than 80% ODC induction produced by treatment with 5 mg/kg TP, the same dose did not significantly affect ODC when the dose of TP was increased up to 100 mg/kg. Higher concentration of RU-486 (200 mg/kg) clearly inhibited the increase in ODC produced by treatment with TP 100 mg/kg; (3) RU-486 was more effective in blocking the anabolic effects produced by stanozolol, a steroidal anabolizing agent, than those produced by testosterone; and (4) RU-486 was less effective than the nonsteroidal antiandrogen flutamide in inhibiting renal ODC activity in male mice. Our results clearly indicate that RU-486 possesses moderate antiandrogenic activity in mouse kidney. The possibility that RU-486 may have similar effects in man should be considered when using this drug.

Neuronal regulation of ornithine decarboxylase induced by androgens in the mouse kidney

1. Neuronal, but not circulating catecholamines, regulate the induction of ornithine decarboxylase (ODC) by testosterone in the mouse kidney. 2. Central and peripheral catecholamine-depleting agents, such as reserpine or alpha-methyl-p-tyrosine, exerted a more pronounced effect on renal ODC than the selective agents tetrabenazine or guanethidine. 3. Benserazide and haloperidol decreased the induction of renal ODC produced by testosterone in female mice. 4. Renal denervation produced a partial inhibition of renal ODC in male mice and decreased the induction of ODC elicited by testosterone in female mice. 5. These results suggest that both peripheral sympathetic neurons as well as central related factors can modulate the effect of androgens on renal ODC activity.

An evaluation of the role of polyamines in different models of kidney hypertrophy in mice

The role of ornithine decarboxylase (ODC) and polyamines in kidney hypertrophy is controversial. Since part of this controversy could be related to differences in the model system used by the different authors, we studied the changes in renal ODC and polyamines in six different models of kidney hypertrophy in mice, including compensatory renal hypertrophy produced by unilateral nephrectomy, experimental diabetes, potassium depletion and treatment with hormones such as testosterone, thyroxine and fluorocortisone. Only in the case of renal hypertrophy produced by testosterone administration was there a significant increase in ODC activity and putrescine content in the kidneys. However, the concomitant treatment with difluoromethylornithine (DFMO), an irreversible inhibitor of ODC, as a 2% solution in the drinking water completely abolished the increase of renal ODC, but the kidney weights increased and other androgenic effects, such as the induction of renal beta-glucuronidase, were not affected. Moreover, DFMO-treatment did not prevent the kidney enlargement produced in other types of hypertrophy, even in the cases associated with hyperplasia. The present results support the premise that, at least in mice, the increase in ODC activity and polyamine biosynthesis is not required for kidney growth, and also that in most cases renal enlargement is not accompanied by any increase in the polyamine content.

Involvement of polyamines in the contragestational effect of hyperthermia

Although hyperthermia produces teratogenic effects in a great variety of animal species, the molecular mechanisms by which hyperthermia exerts its action remain unknown. We have studied the implications of polyamines in contragestational hyperthermia in rats. Our results show that the contragestational action of hyperthermia when applied in consecutive periods during days 8, 9 and 10 of rat pregnancy could be completely prevented by the previous administration of polyamines (putrescine and spermidine, 0.6 mmoles/kg and 0.03 mmoles/kg respectively) in combination with the diamine oxidase inhibitor aminoguanidine or by this inhibitor alone (0.12 mmoles/kg). The administration of polyamines alone partially prevented the fetotoxic effect of hyperthermia but produced a marked mortality (50%) in the pregnant rats. These findings support a major and complex role of polyamines in the mechanisms of hyperthermia-mediated teratogenesis, and suggest that the oxidative catabolism of polyamines could be in part responsible of the deleterious effect produced by hyperthermia in rat pregnancy.

Prevalence of hepatitis C virus among candidates for blood donation at the Hospital General de Mexico

Among the NonA-nonB hepatitis, only hepatitis C is exclusively of parenteral transmission. The reported seroprevalence among blood donors in the world ranges from 0.5 to 6.0%. In order to discover the seroprevalence of anti-HCV in candidates for blood donation at the General Hospital of Mexico, 330 individuals were studied. Determination of anti-HCV was performed by the UBI HCV EIA diagnostic test. Risk factors such as history of major surgery, transfusions, drug addiction, etc were also assessed. There were only 4 seropositive patients (1.2%), 95% CI = (0, 2.75%). Only major surgery was associated with seropositivity. It was not possible to exclude hemotransfusion during surgery as a risk factor.

Postnatal development of ornithine decarboxylase and polyamines in the mouse kidney: influence of testosterone

The role of ornithine decarboxylase (ODC) and polyamines in kidney growth during the postnatal development of mice and the influence of testosterone were investigated. A marked sexual dimorphism in renal size was evident after the 3rd week of life, corresponding with the rise in circulating testosterone and the increase in renal ODC and urinary excretion of putrescine in male mice. Renal putrescine and spermidine gradually decreased during the first 3 weeks of life and did not correlate with ODC activity. Treatments with alpha-difluoromethylornithine, and ODC-specific inhibitor, and the antiandrogen flutamide during weeks 4 and 5 showed that both compounds decreased renal ODC activity but only flutamide impaired kidney growth, suggesting that renal growth in mice is regulated by androgens but is independent of the induction of ODC activity.

Catecholamines are required for testosterone induction of ornithine decarboxylase in the mouse kidney

This report presents a study on the influence of the adrenergic system on androgen-regulated ornithine decarboxylase activity (ODC) in the mouse kidney. We have found that the existing levels of renal ODC in male mice and the increase induced by testosterone in male, female, castrated male and hypophysectomized mice were dramatically impaired by catecholamine depletion produced by treatment with either alpha-methyl-p-tyrosine or reserpine. Blockade of beta-receptors by treatment of the animals with the antagonists propranolol or bisoprolol was unable to prevent the effect of testosterone on the renal enzyme. However, alpha i-blockade obtained by treatment with prazosin or phenoxybenzamine was partially effective to produce the decrease of basal ODC in control male or to diminish ODC induction produced by androgens. All these findings demonstrate that catecholamines and alpha 1-adrenergic receptors are implicated in androgen-regulated ODC activity in the mouse kidney and suggest a plausible role of sympathetic renal innervation in enzyme induction by steroid hormones in this organ.

Some characteristics of threonine transport across the blood-brain barrier of the rat

Threonine entry into brain is altered by diet-induced changes in concentrations of plasma amino acids, especially the small neutrals. To study this finding further, we compared effects of various amino acids (large and small neutrals, analogues, and transport models) on transport of threonine and phenylalanine across the blood-brain barrier. Threonine transport was saturable and was usually depressed more by natural large than small neutrals. Norvaline and 2-amino-n-butyrate (AABA) were stronger competitors than norleucine. 2-Aminobicyclo[2.2.1]heptane-2-carboxylate (BCH), a model in other preparations for the large neutral (L) system, and cysteine, a proposed model for the ASC system only in certain preparations, reduced threonine transport; 2-(methylamino)isobutyrate (MeAIB; a model for the A system for small neutrals) did not. Phenylalanine transport was most depressed by cold phenylalanine and other large neutrals; threonine and other small neutrals had little effect. Norleucine, but not AABA, was a strong competitor; BCH was more competitive than cysteine or MeAIB. Absence of sodium did not affect phenylalanine transport, but decreased threonine uptake by 25% (p less than 0.001). Our results with natural, analogue, and model amino acids, and especially with sodium, suggest that threonine, but not phenylalanine, may enter the brain partly by the sodium-dependent ASC system.

The reliability of duplex derived haemodynamic measurements in the assessment of femoro-distal grafts

The aim of this study was to assess the reliability of flow and velocity measurements obtained in the postoperative period by duplex scan monitoring of femoro-distal bypass grafts. Three points along each of 24 grafts were studied by 2 independent observers using a Diasonics 300 DRF duplex scanner. Results obtained for diameter, peak systolic velocity (PSV) and flow were compared. The mean PSV for all points studied was 70 cm/s (S.D. = 14.5): comparing observers the calculated experimental error (EE) for all points was 11 cm/s (coefficient of EE = 15%). In contrast, the experimental error for flow was 44.5 ml/min (coefficient of EE = 31). The mean flow for all grafts was 142 ml/min (S.D. = 66.5). Flow at the different points of individual grafts could also be compared since routine postoperative intravenous angiography showed all grafts to be devoid of branches. The coefficient of experimental error for flow was 58%. Four of the grafts studied were found to have asymptomatic stenoses. These 4 grafts had low flows (mean = 42 ml/min) but so did 7 other non-stenotic grafts. Although PSV measurements entailed a 15% error, the mean change in PSV in relation to the stenoses was 350%. These data suggest that flow is an unreliable measurement. PSV is more reliable, changes exponentially with luminal diameter and can detect, and perhaps grade, asymptomatic stenoses.

Characterization by enzyme-linked immunosorbent assay of the humoral immune response in patients with neurocysticercosis and its application in immunodiagnosis

The enzyme-linked immunosorbent assay was standardized for the search for specific antibodies in human neurocysticercosis. A crude cysticercal extract and two partially purified antigenic fractions were used, as well as serum and cerebrospinal fluid (CSF) samples of different groups of subjects. Immunoglobulin G (IgG) antibodies were detected in serum and CSF, with a sensitivity of 85 and 90%, respectively. Specificity was 96% with a partially purified antigen and 100% with the crude cysticercal extract. IgM and IgA antibodies were detected less frequently, and IgE was detected only occasionally, both in serum and CSF. Analysis of serum and CSF samples drawn from the same patient did not always reveal the presence of anticysticercus antibodies in both samples. A significant correlation was found between the presence or absence of IgG antibodies in the CSF and the morphological appearance of the parasite (undamaged or calcified). Variations in the humoral response were not found to correlate with clinical and laboratory findings.

Host--parasite relationship in cysticercosis: immunologic study in different compartments of the host

Cysticerci parasitize several mammalian species, including man, in which the parasitic disease shows unique characteristics since cysticerci are established mainly in immunologically privileged sites and can survive for many years. The study of the human immune response to cysticerci is helpful in diagnosis and could perhaps also aid in preventing or curing the disease. Anti-cysticercus IgG can be detected in serum and cerebrospinal fluid (CSF) of almost all patients with neurocysticercosis, by the enzyme-linked immunosorbent assay (ELISA); antibodies of the other classes are found less frequently. Antibodies react with up to eight Taenia solium cysticercus antigens, mainly with antigen B. This antigen has an affinity for collagen and is not commonly found in the CSF. It could therefore be participating in vasculitic processes spotted in the brain of neurocysticercotic patients. Immunoglobulins are also identified on the surface of the parasites: IgG is detected on parasites obtained from various tissues; IgM, IgA and IgE mostly on extracerebral cysticerci. We discuss the possibility of extraneural cysticerci being destroyed by the immune response of the host whereas natural aging may cause brain cysticerci death.

Iliac arteriovenous fistula as a complication of lumbar disc surgery. Report of two cases and review of literature

Vascular lesions following surgery of the lumbar disc are very infrequent, and exceptionally an arteriovenous fistula can developed. An important proportion of the reported cases were previously diagnosed as deep venous thrombosis, because this kind of pathology was not suspected. Postsurgical arteriovenous fistula produces severe haemodynamic disturbances, and congestive heart failure will develop if they are left to their natural course without intervention. Arteriovenous fistula should be suspected in the post-operative period of the lumbar disc surgery if congestive heart failure appears, accompanied by swelling of one or both lower limbs. Early surgery is the treatment of choice in order to prevent the congestive heart failure, and to preserve the normal function of the lower extremities. The technical choice seems to be the closure of the orifice of the fistula through the arterial lumen, together with appropriate arterial reconstruction.

Abdominal aortic aneurysms. Results of surgical treatment

One hundred and twenty-one aneurysms of the abdominal aorta were operated on during a ten year period (1971-1981). Elective surgery was carried out in 89 patients (73.5%). Thirty-two patients were operated on for impending or frank rupture. Most of the patients treated electively had no symptoms on admission. The mortality of this group of patients was 6.7% (6 patients). All the patients treated as emergencies had acute abdominal or back pain. Six cases presented with shock and acute renal failure. The hospital mortality was high in this group of 11 patients (34.3%). Nine of them were operated on because of suspected rupture but this was not confirmed at operation. Only one patient in this group died after the operation (11.1%). The hospital mortality of the 23 patients with ruptured aneurysms was 43.4% (10 patients). Six of them died in the operating room. While elective surgery carries an acceptable mortality, the emergency procedure involves a high risk. All the aneurysms must be resected electively in spite of the absence of symptoms.

Effect of oral contraceptive use on the erythrocytic glutathione reductase and aspartate aminotransferase activities in women with or without clinical signs of vitamin deficiency

The effect of the chronic use of combined oral contraceptives (OCs) on the "activity coefficients" (alpha = coenzyme-stimulated activity/basal activity) of erythrocytic glutathione reductase and aspartate aminotransferase was studied in 2 groups of 90 female volunteers each; 1 of the groups, from the state of Yucatan in southeast Mexico, presented clinical lesions of vitamin deficiency, while the other group, from Mexico City, did not have any clinical evidence of vitamin deficiency. One half of the women (45) in each group were chronic OC users and the other half were not. The results were analyzed comparing OC users with non-users in each location. For both glutathione reductase and aspartate aminotransferase, the Mexico City OC users had significantly higher (p 0.001) alpha values than nonusers, while in the Yucatan women, the alpha values were similarly high independent of OC use.

A monoclonal antibody detaches embryonic skeletal muscle from extracellular matrices

We have described a monoclonal antibody that rounds and detaches chick skeletal myoblasts and myotubes from extracellular substrata. The antibody also inhibits the attachment of myogenic cells to a gelatin-coated substratum but has no detectable effect on myoblast fusion. The cellular response to antibody treatment varies with differentiation and cell type. Young myoblasts and myotubes are rapidly rounded and detached by the antibody. Older myotubes require longer incubation times or higher antibody titers for rounding and detachment. Chick embryo fibroblasts, cardiac cells, and neurons are not similarly rounded and remain attached. Since the antibody also detaches cells from embryonic muscle tissue explants, the cell-substratum interaction perturbed by the antibody appears relevant to the in vivo interaction of myogenic cells with their extracellular matrices. Binding studies using iodinated antibody revealed 2-4 x 10(5) sites per myoblast with an apparent Kd in the range of 2-5 x 10(-9) molar. Embryo fibroblasts bind antibody as well and display approximately twice the number of binding sites per cell. The fluorescence distribution of antigen on myoblasts and myotubes is somewhat punctate and particularly bright along the edge of the myotube. The distribution on fibroblasts was also punctate and was particularly bright along the cell periphery and portions of stress fibers. For both cell types the binding was distinctly different than that reported for collagen, fibronectin, and other extracellular molecules. The antigen, as isolated by antibody affinity chromatography, inhibits antibody-induced rounding. SDS PAGE reveals two unique polypeptides migrating in the region of approximately 120 and 160 kilodaltons (kd). The most straightforward mechanism for the antibody-induced rounding and detachment is the perturbation of a membrane molecule involved in adhesion. The hypothesized transmembrane link between extracellular macromolecules and the cytoskeleton provides an obvious candidate.