SARS-CoV-2 Humoral Immunity Persists Following Rituximab Therapy.

Long-term humoral immunity is mediated by short-lived plasma cells (replenished by memory B cells) and long-lived plasma cells. Their relative contributions are uncertain for immunity to SARS-CoV-2, especially given the widespread use of novel mRNA vaccines. Yet, this has far-reaching implications in terms of the need for regular booster doses in the general population and perhaps even revaccination in patients receiving B cell-depleting therapy. We aimed to characterise anti-SARS-CoV-2 antibody titres in patients receiving Rituximab following previous SARS-CoV-2 vaccination. We recruited 10 fully vaccinated patients (age: 16.9 ± 2.52 years) with childhood-onset nephrotic syndrome, not in relapse, receiving Rituximab for their steroid/calcineurin-inhibitor sparing effect. Antibodies to SARS-CoV-2 spike (S) and nucleocapsid (N) proteins were measured immediately prior to Rituximab and again ~6 months later, using the Roche Elecys® Anti-SARS-CoV-2 (S) assay. All ten patients were positive for anti-S antibodies prior to Rituximab, with six patients (60%) having titres above the upper limit of detection (>12,500 U/mL). Following Rituximab therapy, there was a reduction in anti-S titres (p = 0.043), but all patients remained positive for anti-S antibodies, with five patients (50%) continuing to have titres >12,500 U/mL. Six patients (60%) were positive for anti-N antibodies prior to Rituximab. Following Rituximab therapy, only three of these six patients remained positive for anti-N antibodies (p = 0.036 compared to anti-S seroreversion). Humoral immunity to SARS-CoV-2 is likely to be mediated in part by long-lived plasma cells.

Trauma-informed prevention programmes for depression, anxiety, and substance use among young people: protocol for a mixed-methods systematic review.

BACKGROUND: Mental ill-health and substance use bear a substantial burden and harm on young people and often arise from co-occurring and compounding risk factors, such as traumatic stress. Trauma-informed prevention of mental ill-health and substance use demonstrates significant promise in reducing this burden. A systematic literature review is required to identify and summarise the effectiveness, feasibility, acceptability, and design principles underpinning existing trauma-informed mental ill-health and/or substance use prevention programmes for young people aged 12-24 years. METHODS: MEDLINE, Embase, CINAHL, PsychINFO, and Cochrane Library will be searched from 2012 through September 2022. Reference lists of included articles will be citation-chained. Title and abstracts will be screened and two reviewers will review articles full-text. One reviewer will extract data from eligible articles using a piloted data extraction form, and 20% of the data will be verified by a second reviewer. Risk of bias will be assessed using the Cochrane risk-of-bias tool for randomised trials (RoB 2), Risk of Bias in Non-randomised Studies of Interventions (ROBINS-I), and The Joanna Briggs Institute Critical Appraisal Checklist for Quasi-Experimental Studies and The Joanna Briggs Institute Critical Appraisal Checklist for Qualitative Research (CASP), depending on the study type. Characteristics of existing trauma-informed mental ill-health and/or substance use prevention programmes for young people will be summarised narratively. Effectiveness, feasibility, and acceptability will be qualitatively described and summarised, with proportions and effect sizes quantitatively synthesised, where possible. DISCUSSION: Trauma-informed approaches to prevention demonstrate significant promise, yet to date, no study has systematically summarised and synthesised the available literature. To fill this gap, the present review will systematically identify and summarise the effectiveness, feasibility, acceptability, and design principles underpinning existing trauma-informed mental health and/or substance use prevention programmes for young people aged 12-24. This review will inform the development, adaptation, evaluation, and implementation of future trauma-informed mental ill-health and substance use prevention programmes for young people. Findings will inform critical efforts to interrupt and prevent already elevated trajectories of mental ill-health, substance use, and related harms among those young people exposed to adversity. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42022353883.

Association between mental health workforce supply and clusters of high and low rates of youth suicide: An Australian study using suicide mortality data from 2016 to 2020.

OBJECTIVE: To examine the association between mental health workforce supply and spatial clusters of high versus low incidence of youth suicide. METHODS: A cross-sectional analysis of spatial suicide clusters in young Australians (aged 10-25) from 2016 to 2020 was conducted using the scan statistic and suicide data from the National Coronial Information System. Mental health workforce was extracted from the 2020 National Health Workforce Dataset by local government areas. The Geographic Index of Relative Supply was used to estimate low and moderate-to-high mental health workforce supply for clusters characterised by a high and low incidence of suicide (termed suicide hotspots and coldspots, respectively). Univariate and multivariate logistic regression was used to determine the association between suicide clusters and a range of sociodemographic characteristics including mental health workforce supply. RESULTS: Eight suicide hotspots and two suicide coldspots were identified. The multivariate analysis showed low mental health workforce supply was associated with increased odds of being involved in a suicide hotspot (adjusted odds ratio = 8.29; 95% confidence interval = 5.20-13.60), followed by residential remoteness (adjusted odds ratio = 2.85; 95% confidence interval = 1.68-4.89), and illicit drug consumption (adjusted odds ratio = 1.97; 1.24-3.11). Both coldspot clusters occurred in areas with moderate-to-high mental health workforce supply. CONCLUSION: Findings highlight the potential risk and protective roles that mental health workforce supply may play in the spatial distributions of youth suicide clusters. These findings have important implications for the provision of postvention and the prevention of suicide clusters.

Retrograde signaling by a mtDNA-encoded non-coding RNA preserves mitochondrial bioenergetics.

Alveolar epithelial type II (AETII) cells are important for lung epithelium maintenance and function. We demonstrate that AETII cells from mouse lungs exposed to cigarette smoke (CS) increase the levels of the mitochondria-encoded non-coding RNA, mito-RNA-805, generated by the control region of the mitochondrial genome. The protective effects of mito-ncR-805 are associated with positive regulation of mitochondrial energy metabolism, and respiration. Levels of mito-ncR-805 do not relate to steady-state transcription or replication of the mitochondrial genome. Instead, CS-exposure causes the redistribution of mito-ncR-805 from mitochondria to the nucleus, which correlated with the increased expression of nuclear-encoded genes involved in mitochondrial function. These studies reveal an unrecognized mitochondria stress associated retrograde signaling, and put forward the idea that mito-ncRNA-805 represents a subtype of small non coding RNAs that are regulated in a tissue- or cell-type specific manner to protect cells under physiological stress.

Decision analysis supports the use of drain amylase-based enhanced recovery method after esophagectomy.

Postesophagectomy anastomotic leak is a common postsurgical complication. The current standard method of detecting leak is esophagram usually late in the postoperative period. Perianastomotic drain amylase level had shown promising results in early detection anastomosis leak. Previous studies have shown that postoperative day 4 amylase level is more specific and sensitive than esophagram. The purpose of this study is to determine if implementing a drain amylase-based screening method for anastomotic leak can reduce length of stay and hospital cost relative to a traditional esophagram-based pathway. The drain amylase protocol we propose uses postoperative day 4 drain amylase level to direct the initiation of PO intake and discharge. We designed a decision analysis tree using TreeAge Pro software to compare the drain amylase-based screening method to the standard of care, the esophagram. We performed a retrospective review of postesophagectomy patients from a tertiary academic medical center (University hospital Cleveland medical center) where amylase level was measured routinely postoperatively. The patients were separated into amylase-based pathway group and the standard of care group based on their postop management. The length of stay, costs, complications, and leak rate of these two groups were used to inform the decision analysis tree. In the base-case analysis, the decision analysis demonstrated that an amylase-based screening method can reduce the hospital stay by one day and reduced costs by ∼$3,000 compared to esophagram group. To take the variability of the data into consideration, we performed a Monte Carlo simulation. The result showed again a median saving of 0.71 days and ∼$2,500 per patient in hospital cost. A ballistic sensitivity analysis was performed to show that the sensitivity of postoperative day 4 amylase level in detecting a leak was the most important factor in the model. We conclude that implementing an amylase-based screening method for anastomotic leak in postesophagectomy patient can significantly reduce hospital cost and length of stay. This study demonstrates a novel protocol to improve postesophagectomy care. Based on this result, we believe a prospective multicenter study is appropriate.

The influence of growth hormone replacement on peripheral inflammatory and cardiovascular risk markers in adults with severe growth hormone deficiency.

BACKGROUND: Adult GHD syndrome is associated with clustering of adverse cardiovascular (CV) risk factors such as abnormal body composition, dyslipidemia, insulin resistance and abnormal haemostatic factors. There is a wealth of evidence linking CV events with elevated levels of inflammatory markers (hs-CRP and IL-6) in the general population; however data on their abnormalities in GHD and specially the effects of GH replacement (GHR) on these inflammatory markers are limited. OBJECTIVE: To study the effects of GHR on inflammatory markers, glucose homeostasis and body composition in a cohort of adults with recently diagnosed severe GHD due to hypothalamic pituitary disease. DESIGN: Fifteen hypopituitary adults (11 males, mean age 48.5 years) with recently diagnosed, severe GHD were recruited. Patients received GHR (in addition to other pituitary hormone replacements) titrated to clinical response and to normalize age and gender adjusted IGF-1 levels. Weight, waist hip ratio (WHR), body composition, fasting plasma glucose and insulin, insulin resistance index (HOMA-IR), fasting serum lipid levels, hs-CRP, IL-6 and TNF-alpha were measured at baseline and following a minimum 6 months of stable maintenance GHR. RESULTS: GHR resulted in a physiological increase in IGF-1 SDS [median -0.6 to +0.39, P<0.0001], improved quality of life (mean pre-treatment AGHDA score 16 vs. post-treatment score 7, P<0.0001) and reduction in WHR (0.94 vs. 0.92, P=0.01). There were no significant changes in body weight and composition. Levels of hs-CRP (log transformed, mean (SD)) were significantly reduced following GHR (pre 1.21 (0.9) vs. post 0.27 (0.9), P<0.0001) but TNF-alpha and IL-6 levels remained unchanged. Fasting glucose (mmol/L) [4.6 (0.1) vs. 5.1 (0.1), P=0.003], fasting insulin (muU/mL) [9.4 (8.1) vs. 12.1 (9.2), P=0.03] and HOMA-IR [1.2 (1.0) vs. 1.5 (1.1) P=0.02] (all pre-GHR vs. post-GHR and mean (SD)) significantly increased following GHR indicating increased insulin resistance. Significant improvements were noted in fasting LDL-cholesterol (LDL-C) and HDL-cholesterol (HDL-C) levels following GHR [3.4 (0.9) vs. 2.9 (0.7), P=0.03 and 1.2 (0.2) vs. 1.3 (0.2), P=0.02, respectively] (all pre-GHR vs. post-GHR and mean (SD)). Levels of total cholesterol and triglycerides did not change following GHR. CONCLUSIONS: Physiological GHR for at least 6 months in hypopituitary adults with recently diagnosed severe GHD resulted in favourable changes in hs-CRP, WHR, fasting LDL-C and HDL-C levels all of which are recognised CV risk markers. However, there remains a high prevalence of obesity in this population and given the worsening of insulin sensitivity in the short term with GHR, monitoring and aggressive treatment of established CV risk factors is essential to reduce premature atherosclerotic CVD in this patient population.

Relations among physical activity, physical fitness, and self-perceived fitness in Hong Kong adolescents.

The relationships between physical fitness, activity, and self-perceived fitness in adolescents in Hong Kong were investigated. Regular physical activity patterns, self-perceptions of fitness, and health-related physical fitness were measured in 201 secondary school students (M age = 13.8 yr.). The battery of fitness tests measured cardiovascular capacity, flexibility, muscular strength, muscular endurance, and body fat composition. The boys had a higher self-perception of their own fitness and exercised more outside school than the girls. Participation in physical activity was related to cardiovascular capacity, muscular strength, and body composition. Linear regression analysis indicated that exercise activity and body composition explained a portion of variance in the subjects' self-perceived fitness. These findings highlight the connections between physical activity, fitness, and self-perception of fitness and consequently the need for understanding the concept for better health-promotion strategies.

Outcomes of minimally invasive esophagectomy (MIE) for high-grade dysplasia of the esophagus.

OBJECTIVE: The management of high-grade dysplasia (HGD) of the esophagus is controversial with some clinicians advocating non-operative ablation or surveillance. Minimally invasive esophagectomy (MIE) allows re-section of the esophagus and may minimize morbidity. This report summarizes our experience with MIE for HGD. METHODS: A retrospective review of 28 patients who underwent MIE for a pre-operative diagnosis of HGD. MIE initially involved a laparoscopic transhiatal approach (n=1), but subsequently evolved to laparoscopy with VATS mobilization (n=27) of the esophagus. RESULTS: From August 1996 to March 2001, 28 patients underwent MIE. There were 23 males and five females; median age was 61 (40-78) years. Median hospital stay was 5 (3-20) days and ICU stay was 1 (1-20) day. One patient required conversion to laparotomy because of dense adhesions. There were ten other patients who had successful MIE despite prior laparotomy. Median operating time was 8 (5.8-13) h. One death occurred from sepsis, pneumonia and multi-system organ failure. Complications occurred in 15 patients. In addition to the patient who died, five re-operations were required for: small bowel perforation (n=1), jejunostomy leak (n=1), pyloric dilation for gastric outlet obstruction (n=1), cholecystectomy (n=1), incision and drainage of an abdominal abscess (n=1). Final pathologies were HGD (n=17), in situ cancer (n=6) and invasive cancer (n=5). At a median follow-up of 13 (2-41) months all hospital survivors are alive and free of disease. CONCLUSIONS: This report confirms the risk of occult cancer in patients with HGD (39% in this series) supporting the recommendation for esophagectomy. MIE can be performed with acceptable results and may minimize morbidity compared to previous reports of open esophagectomy for HGD.

Laparoscopic cholecystectomy: what does affect the outcome? A retrospective multifactorial regression analysis.

BACKGROUND: The association between various factors and the postoperative outcome has not been thoroughly studied in laparoscopic cholecystectomy (LC). The aim of this retrospective study was to determine which factors significantly affect patients outcome after LC. METHODS: The medical and operative records of all consecutive patients who underwent LC at our institution from 1991 to 1996 were reviewed. The effect of age, medical and surgical history, duration of procedure, and setup (urgent or elective) on the postoperative complication rate and on the length of postoperative hospital stay (LOS) were analyzed using multiple linear regression and logistic regression analysis. Overall, 601 patients were included in the study. RESULTS: The factors that significantly prolonged LOS were age (p = 0.0145), acute cholecystitis (p = 0.0006), history of ischemic heart disease (p = 0.0332), and duration of procedure (p < 0.0001). A significantly higher postoperative morbidity rate was noted in patients who had a procedure longer then 2 h than in patients whose surgery required less the 2 h (13.6% vs 3.6%, respectively; p < 0.0001). Similarly, higher morbidity was noted in elderly patients than in younger patients (16% vs 6.1%; p = 0.0005). Other factors that significantly increased postoperative morbidity included acute cholecystitis (p = 0.023), a history of cholangitis (p = 0.018), and diabetes (p = 0.05). CONCLUSIONS: According to this study, advanced age, longer duration of procedure, and acute cholecystitis significantly increase both the postoperative morbidity and the LOS. History of ischemic heart disease significantly increases LOS, but does not increase morbidity after LC.

Sudden death in patients after transcatheter device implantation for congenital heart disease.

To explore whether transcatheter intracardiac devices increase risk for sudden death, we analyzed patient and device-related variables with a case-control design. Sudden death was defined as unexpected death with abrupt onset and rapid deterioration. Cases included all patients known to have died suddenly after device closure at our institution, using 3 large databases. Controls (2:1), matched on year of procedure, were chosen randomly from the same databases. Data were obtained from medical record review. Of 777 patients who received implants between February 1989 and February 1999, 9 were known to have died suddenly (1.2%). In 27 cases and controls, diverse defects were occluded: atrial (n = 16), ventricular (n = 4), Fontan fenestration (n = 4), or other (n = 3). Cases were more likely to have had a history of serious arrhythmias (p = 0.008), severe valve regurgitation (p = 0.03), > or =1 cardiac surgery (p = 0.009), and multiple devices (p = 0.03). Cases were somewhat more likely to have pulmonary hypertension (p = 0.09), ventricular dysfunction (p = 0.09), and nonatrial septal defects (p = 0.10). Patients were less likely to have device arm fractures (p = 0.05). The following were not related to sudden death: age, weight, gender, low systemic cardiac index, end-diastolic pressure, major noncardiac disease, serious adverse events, maximum device size, malposition, and residual leak. This study suggests that sudden death was more likely to occur in device-implanted patients who had severe underlying cardiac disease and/or multiple devices. No other device-related variables were associated with sudden death.

Pancreaticojejunostomy versus controlled pancreaticocutaneous fistula in pancreaticoduodenectomy for periampullary carcinoma.

BACKGROUND: Anastomotic leak of the pancreaticojejunostomy is a major cause of morbidity and mortality following pancreaticoduodenectomy. Reports have described a large variety of techniques for performing this anastomosis and managing the pancreatic stump. In an attempt to obviate the pancreaticojejunostomy, we prospectively studied the technique of ligating the pancreatic duct and using external drains to create a temporary controlled pancreaticocutaneous fistula. PATIENTS AND METHODS: Thirty-five consecutive patients who were to undergo pancreaticoduodenectomy for periampullary carcinoma were prospectively randomized to one of two groups: pancreaticojejunostomy (PJ) (n = 18) or controlled pancreaticocutaneous fistula (CPF) (n = 17). The groups were well matched for age, sex, coexisting medical illnesses, type of tumor, and preoperative condition. Except for the management of the pancreatic remnant, all patients in both groups underwent an identical procedure. Major morbidity, length of hospitalization, duration of the controlled pancreatic fistula, and mortality were analyzed over a mean follow-up interval of 26 months (range 5 months to 7.5 years). RESULTS: The CPF group experienced lower overall operative morbidity rates than the PJ group (24% versus 56%, P < 0.01). Two patients (11%) in the PJ group and none in the CPF group died (P = NS). Half the morbidity in the PJ group and both mortalities were related to anastomotic leak. The CPF and PJ groups left the hospital after mean stays of 26.4 and 42.2 days respectively (< 0.01). CONCLUSIONS: Compared to pancreaticojejunal anastomosis, creation of a temporary controlled pancreaticocutaneous fistula in patients who undergo pancreaticoduodenectomy for periampullary malignancy has no appreciable risk. It is associated with reduced morbidity and shorter length of hospitalization.

Preliminary localization of a gene for autosomal dominant hypoparathyroidism to chromosome 3q13.

A large family in which hypoparathyroidism was observed to segregate as an autosomal dominant trait in three generations was identified. Mutation in the PTH gene was excluded by linkage and single-stranded conformational analysis. The hypocalcemic phenotype in this family was mapped by linkage analysis using short, tandem-repeat polymorphisms to the region of chromosome 3q13. A maximum lod score of 2.71 at theta = 0.0 was observed with marker D3S1303. Positive lod scores were observed at theta = 0.0 with markers flanking D3S1303. Multipoint linkage analysis gave a lod score of 2.71 for the region flanking D3S1303. Simulation using the computer program SLINK showed that a lod score of 2.71 at theta = 0.0 was the maximum lod score possible given the pedigree structure. The simulation also showed that given the structure of the pedigree the probability of observing a lod score of 2.71 at theta = 0.0 by chance was 1 in 1000. The data presented above provide important preliminary evidence supporting linkage to chromosome 3q13. This region contains a Ca(2+)-sensing receptor gene that is proposed as a key signal transduction element for changes in extracellular Ca2+ concentrations in mechanisms of regulation of PTH secretion from parathyroid cells. The mutation in this family may activate the Ca(2+)-sensing receptor suppressing PTH secretion and lowering the "set point" for serum calcium levels.

Serum lipid profile determines platelet reactivity to native and modified LDL-cholesterol in humans.

The effects of thrombin (0.2 U/ml) and native (n-LDL), malondialdehyde-modified (MDA-LDL) and auto-oxidized (ox-LDL) low-density lipoproteins (20 micrograms of protein/ml) on platelet activation were evaluated in seven hyperlipidemic patients and compared to seven controls (fasting serum cholesterol 8.49 +/- 0.5 and 4.61 +/- 0.4 mM, respectively). Basal and thrombin-induced increases in platelet intracellular free calcium ion concentration ([Ca2+]i; fura-2) were similar in hyperlipidemic patients and controls (45 +/- 5 vs 42 +/- 3 and 635 +/- 51 vs 599 +/- 69 mM, respectively). n-LDL, MDA-LDL and ox-LDL increased basal [Ca2+]i (16, 36 and 81 percent, p < 0.01 between LDL-types), increases were consistently smaller in patients. There was an inverse relationship between LDL-induced responses and fasting serum LDL cholesterol as well as LDL/HDL ratio. In conclusion, modified LDL activated platelets to a greater extent than n-LDL, suggesting different types of LDL-receptors. Their agonistic effect was inversely related to the fasting serum lipid profile, suggesting that blunting of platelet responses to LDL could represent a protective mechanism in hyperlipidemic patients.

Temperature-dependence of LDL binding and activation of human platelets.

The effect of low density lipoprotein (LDL) on intracellular free calcium ion concentration ([Ca2+]i), taken as an index of the degree of platelet activation, was investigated in normal volunteers. At 37 degrees C LDL, in a dose of 20 micrograms of protein/ml, increased [Ca2+]i in all subjects tested (basal 57 +/- 11 to 113 +/- 19 nM). In contrast, when measurements were performed at 20 degrees C, no effect on [Ca2+]i was seen following LDL. Thrombin (0.2 U/ml) increased [Ca2+]i to 455 +/- 98 nM. When platelets had been exposed to LDL before thrombin stimulation, this increase was less pronounced (to 301 +/- 43 nM). Our finding of a temperature dependence of LDL induced increase in platelet [Ca2+]i supports the concept of a platelet-LDL receptor mediated mechanism. Furthermore, the lower thrombin response following LDL exposure suggests a LDL-thrombin interaction, possibly at the thrombin receptor level and/or calcium recruitment from the same stores.

Allgrove syndrome: an autosomal recessive syndrome of ACTH insensitivity, achalasia and alacrima.

Allgrove syndrome (isolated glucocorticoid deficiency, achalasia and alacrima) was found in eight members of an inbred French Canadian/North American Indian pedigree. The high degree of consanguinity supports an autosomal recessive mode of inheritance for this disorder. Six patients presented with hypoglycaemia and other evidence of cortisol deficiency between 2.5 and 8 years of age; however, two others became cortisol deficient after initial testing showed normal cortisol responses to ACTH, evidence that the glucocorticoid insufficiency of this syndrome may not be congenital, but may develop as late as the third decade. No evidence of mineralocorticoid deficiency has been found during 65 patient-years of follow-up. Alacrima was the earliest and most consistent clinical sign of Allgrove syndrome. Other manifestations of peripheral or autonomic neuropathy were found in four patients. The patients showed similar facial features, and three had significant velo-pharyngeal incompetence. All showed oesophageal dysmotility even in the absence of symptomatic dysphagia. In-vitro studies of lymphocyte ACTH binding showed no differences from normal controls. If such lymphocyte binding, as has been suggested, reflects adrenal ACTH receptor activity, these data would suggest that the glucocorticoid deficiency of Allgrove syndrome is not the result of a defect in that receptor. However, the observation that ACTH does not elicit increased adenylate cyclase activity even in normal lymphocytes casts considerable doubt on the physiological significance of ACTH binding to lymphocytes. It seems likely, therefore, that true ACTH receptors are not expressed on peripheral lymphocytes, and any conclusions regarding a possible receptor defect in Allgrove syndrome must await studies of receptor expression on adrenal cell membranes.

A stimulatory effect of interleukin-1 on adrenocortical cortisol secretion mediated by prostaglandins.

Studies using cultured bovine adrenocortical cells now demonstrate that the cytokines interleukin-1 (IL-1) alpha and beta, contrary to previous reports, can stimulate cortisol secretion in vitro in a dose- and time-dependent fashion. However detectable levels of IL-1 receptor could not be demonstrated in adrenal cortical, medullary, or capsular cells by membrane displacement of iodinated IL-1 alpha by unlabeled IL-1 beta, a technique that readily demonstrates specific IL-1 alpha-binding sites on 3T3 fibroblasts. The stimulatory effect of IL-1 on cortisol secretion could be totally blocked by indomethacin, an indication that this effect might be mediated indirectly via local release of prostaglandins (PGs). Subsequent investigations have confirmed that IL-1 does enhance the conversion of [3H]arachidonate to PGs by cultured adrenal cells, and that some of these PGs (PGD2, PGF2 alpha, and PGE2), in turn, can stimulate cortisol production. Taken together these observations suggest that IL-1-induced stimulation of cortisol secretion is mediated through local release of PGs by a small subpopulation of cells within the adrenal gland.

Combined 17-hydroxylase and 17,20-desmolase deficiencies: evidence for synthesis of a defective cytochrome P450c17.

We studied in vivo and in vitro steroidogenesis in six phenotypic female children with 17-hydroxylase deficiency. The diagnosis was suspected as a likely cause of familial low renin hypertension and was confirmed by findings of reduced basal and ACTH-stimulated serum and urinary levels of cortisol and other 17-hydroxysteroids, together with hypergonadotropic hypogonadism in both 46,XY and 46,XX patients, and abnormally increased secretion of 17-desoxysteroids, such as progesterone, 11-deoxycorticosterone, and corticosterone. ACTH stimulation testing demonstrated a lesser degree of 17-hydroxylase deficiency in the obligate heterozygous parents; one father had increased basal serum 17-hydroxyprogesterone values, unresponsive to ACTH, suggesting partial Leydig cell 17,20-desmolase deficiency. In vitro kinetic analysis of testicular microsomal enzymes in the affected 46,XY male pseudohermaphrodites confirmed that both 17-hydroxylase and 17,20-desmolase activities were less than 2% of those in age-matched normal subjects. However, in spite of this virtual absence of both enzymatic activities of cytochrome P450c17, Northern blot analysis demonstrated abundant amounts of RNA in these tests that hybridized to a cDNA specific for this P450 enzyme. Moreover, immunoblot analysis of sodium dodecyl sulfate-polyacrylamide gel electrophoresis-resolved testicular microsomes showed an apparently normal content of an immunoreactive protein with a mol wt similar to that of authentic P450c17. These results suggest that these patients have a point mutation in the gene for P450c17; the mutant gene is transcribed, but gives rise to a protein defective in normal 17-hydroxylase and 17,20-desmolase activities.

Kinetic analysis of inhibition of human adrenal steroidogenesis by ketoconazole.

The kinetics of the inhibitory effects of the imidazole antimicrobial ketoconazole on the activities of the steroidogenic enzymes distal to cholesterol side-chain cleavage were studied in human adrenal microsomal and mitochondrial suspensions. Although ketoconazole was a competitive inhibitor of all five enzyme reactions, the effects on 17-hydroxylase, 17,20-desmolase, and 11-hydroxylase activities (Ki = 10(-8) M) were considerably greater than those on 21-hydroxylase and 3 beta-hydroxysteroid dehydrogenase/isomerase activities (Ki = 10(-4) M). These findings explain the clinical endocrine effects of ketoconazole in the usual therapeutic doses, which include inhibition of cortisol and androgen secretion, compensatory ACTH-mediated secretion of 17-desoxysteroids such as progesterone and aldosterone, and suppression of PRA.