Prospective Evaluation of High Titer Autoantibodies and Fetal Home Monitoring in the Detection of Atrioventricular Block Among Anti-SSA/Ro Pregnancies

OBJECTIVE

This prospective study of pregnant patients, Surveillance To Prevent AV Block Likely to Occur Quickly (STOP BLOQ), addresses the impact of anti-SSA/Ro titers and utility of ambulatory monitoring in the detection of fetal second-degree atrioventricular block (AVB).

METHODS

Women with anti-SSA/Ro autoantibodies by commercial testing were stratified into high and low anti-52-kD and/or 60-kD SSA/Ro titers applying at-risk thresholds defined by previous evaluation of AVB pregnancies. The high-titer group performed fetal heart rate and rhythm monitoring (FHRM) thrice daily and weekly/biweekly echocardiography from 17-26 weeks. Abnormal FHRM prompted urgent echocardiography to identify AVB.

RESULTS

Anti-52-kD and/or 60-kD SSA/Ro met thresholds for monitoring in 261 of 413 participants (63%); for those, AVB frequency was 3.8%. No cases occurred with low titers. The incidence of AVB increased with higher levels, reaching 7.7% for those in the top quartile for anti-60-kD SSA/Ro, which increased to 27.3% in those with a previous child who had AVB. Based on levels from 15 participants with paired samples from both an AVB and a non-AVB pregnancy, healthy pregnancies were not explained by decreased titers. FHRM was considered abnormal in 45 of 30,920 recordings, 10 confirmed AVB by urgent echocardiogram, 7 being second-degree AVB, all <12 hours from normal FHRM and within another 0.75 to 4 hours to echocardiogram. The one participant with second/third-degree and two participants with third-degree AVB were diagnosed by urgent echocardiogram >17 to 72 hours from an FHRM. Surveillance echocardiograms detected no AVB when the preceding interval FHRM recordings were normal.

CONCLUSION

High-titer antibodies are associated with an increased incidence of AVB. Anti-SSA/Ro titers remain stable over time and do not explain the discordant recurrence rates, suggesting that other factors are required. Fetal heart rate and rhythm (FHRM) with results confirmed by a pediatric cardiologist reliably detects conduction abnormalities, which may reduce the need for serial echocardiograms.

VRE acquisition in hospital and its association with hospital antimicrobial usage -a non-linear analysis of an extended time series

BACKGROUND

Vancomycin resistant enterococci (VRE) have become endemic pathogens in many Australian hospitals causing significant morbidity. There are few observational studies that have evaluated the effect of antibiotic usage on VRE acquisition. This study examined VRE acquisition and its association with antimicrobial use. The setting was a NSW tertiary hospital with 800 beds over a 63 month period up to March 2020, straddling piperacillin-tazobactam (PT) shortages that occurred from in September 2017.

METHODS

The primary outcome was monthly inpatient hospital onset Vancomycin-resistant Enterococci (VRE) acquisitions. Multivariate adaptive regression splines (MARS) were used to estimate hypothetical thresholds, where antimicrobial use above threshold is associated with increased incidence of hospital onset VRE acquisition. Specific antimicrobials and categorised usage (broad, less broad and narrow spectrum) were modelled.

RESULTS

There were 846 hospital onset VRE detections over the study period. Hospital onset vanB and vanA VRE acquisitions fell significantly by 64% and 36% respectively after the PT shortage. MARS modelling indicated that PT usage was the only antibiotic found to exhibit a meaningful threshold. PT usage greater than 17.4 defined daily doses/1000 occupied bed-days (95%C I: 13.4, 20.5) was associated with higher onset of hospital VRE.

CONCLUSIONS

This paper highlights the large, sustained impact that reduced broad spectrum antimicrobial use had on VRE acquisition and showed that PT use in particular was a major driver with a relatively low threshold. It raises the question as to whether hospitals should be determining local antimicrobial usage targets based on direct evidence from local data analysed with non-linear methods.

Contribution of S100A4-expressing fibroblasts to anti-SSA/Ro-associated atrioventricular nodal calcification and soluble S100A4 as a biomarker of clinical severity

Background

Fibrosis and dystrophic calcification disrupting conduction tissue architecture are histopathological lesions characterizing cardiac manifestations of neonatal lupus (cardiac-NL) associated with maternal anti-SSA/Ro antibodies.

Objectives

Increased appreciation of heterogeneity in fibroblasts encourages re-examination of existing models with the consideration of multiple fibroblast subtypes (and their unique functional differences) in mind. This study addressed fibroblast heterogeneity by examining expression of α-Smooth Muscle Actin (myofibroblasts) and of S100 Calcium-Binding Protein A4 (S100A4).

Methods

Using a previously established model of rheumatic scarring/fibrosis in vitro, supported by the evaluation of cord blood from cardiac-NL neonates and their healthy (anti-SSA/Ro-exposed) counterparts, and autopsy tissue from fetuses dying with cardiac-NL, the current study was initiated to more clearly define and distinguish the S100A4-positive fibroblast in the fetal cardiac environment.

Results

S100A4 immunostaining was observed in 4 cardiac-NL hearts with positional identity in the conduction system at regions of dystrophic calcification but not fibrotic zones, the latter containing only myofibroblasts. In vitro, fibroblasts cultured with supernatants of macrophages transfected with hY3 (noncoding ssRNA) differentiated into myofibroblasts or S100A4⁺ fibroblasts. Myofibroblasts expressed collagen while S100A4⁺ fibroblasts expressed pro-angiogenic cytokines and proteases that degrade collagen. Cord blood levels of S100A4 in anti-SSA/Ro-exposed neonates tracked disease severity and, in discordant twins, distinguished affected from unaffected.

Conclusions

These findings position the S100A4⁺ fibroblast alongside the canonical myofibroblast in the pathogenesis of cardiac-NL. Neonatal S100A4 levels support a novel biomarker of poor prognosis.

Reducing the burden of surveillance in pregnant women with no history of fetal atrioventricular block using the negative predictive value of anti-Ro/SSA antibody titers

BACKGROUND

The risk of fetal atrioventricular block in anti-Ro/SSA antibody-exposed pregnancies with no previous affected offspring is approximately 2%. A high antibody titer is necessary but not sufficient for atrioventricular block, and specific antibody titers do not predict risk. However, there are no data on the negative predictive value of antibody titer to identify pregnancies at low risk of fetal atrioventricular block, and may not require surveillance.

OBJECTIVE

This study aimed to define anti-Ro52 and anti-Ro60 antibody thresholds for the identification of fetuses unlikely to develop atrioventricular block using clinically validated and research laboratory tests.

STUDY DESIGN

This study performed a multicenter review of pregnant subjects who tested positive in their local commercial laboratories for anti-Ro/SSA antibodies at the University of Colorado Children's Hospital (2014-2021) and Phoenix Children's Hospital (2014-2021) and enrolled in the Research Registry for Neonatal Lupus (RRNL) at New York University Langone Medical Center (2002-2021). The subjects were referred on the basis of rheumatologic symptoms or history of atrioventricular block in a previous pregnancy and were retrospectively grouped on the basis of pregnancy outcome. Group 1 indicated no fetal atrioventricular block in current or past pregnancies; group 2 indicated fetal atrioventricular block in the current pregnancy; and group 3 indicated normal current pregnancy but with fetal atrioventricular block in a previous pregnancy. Maternal sera were analyzed for anti-Ro52 and anti-Ro60 antibodies using a clinically validated multiplex bead assay (Associated Regional and University Pathologists Laboratories, Salt Lake City, UT) and a research enzyme-linked immunosorbent immunoassay (New York University). This study calculated the negative predictive value separately for anti-Ro52 and anti-Ro60 antibodies and for the 2 combined using a logistic regression model and a parallel testing strategy.

RESULTS

This study recruited 270 subjects (141 in group 1, 66 in group 2, and 63 in group 3). Of note, 89 subjects in group 1 had data on hydroxychloroquine treatment: anti-Ro/SSA antibody titers were no different between those treated (n=46) and untreated (n=43). Mean anti-Ro52 and anti-Ro60 titers were the lowest in group 1 and not different between groups 2 and 3. No case of fetal atrioventricular block developed among subjects with anti-Ro52 and anti-Ro60 titers of <110 arbitrary units per milliliter using the multiplex bead assay of the Associated Regional and University Pathologists Laboratories (n=141). No case of fetal atrioventricular block developed among subjects with research laboratory anti-Ro52 titers of <650 and anti-Ro60 of <4060 enzyme-linked immunosorbent immunoassay units (n=94). Using these 100% negative predictive value thresholds, more than 50% of the anti-Ro/SSA antibody pregnancies that ultimately had no fetal atrioventricular block could be excluded from surveillance based on clinical and research titers, respectively.

CONCLUSION

Study data suggested that there is a clinical immunoassay level of maternal anti-Ro/SSA antibodies below which the pregnancy is at low risk of fetal atrioventricular block. This study speculated that prospectively applying these data may avert the costly serial echocardiograms currently recommended for all anti-Ro/SSA-antibody positive pregnancies and guide future management.

1040 Evaluation of The Use of Biopatch In Haemodialysis Lines: Are We Reducing the Risk of Infection?

Aim

Children who had the central venous lines inserted for prolonged vascular access usually experience the catheter-related blood stream infection (CRBSI). CRBSI is known to be associated with high morbidity which increases the cost of the healthcare and the chances of mortality. Clinical evidence suggests that the use of biopatch (chlorhexidine-impregnated dressing) is effective in reducing the rate of infection in central venous lines. The aim of our study was to evaluate whether the use of biopatch actually reduced the CRBSI in children who had had haemodialysis lines at our institution.

Method

Theatre logs and electronic records of 46 patients who had haemodialysis lines inserted between 2015-2019 were retrospectively reviewed. These patients were randomly selected.

Results

The total number of lines inserted in 46 patients were 104. The mean of line per patient was 2.2. Out of 104 lines, 22 lines (21%) had confirmed infection.

Conclusions

Infection of the central line is still a significant problem. Infections were more prevalent in cases which did not use biopatch according to the documentation. We believe the rate of infection can be reduced by encouraging the use of biopatch on regular basis for the haemodialysis lines and the proper documentation of its use in the operation notes.

Subpolar North Atlantic western boundary density anomalies and the Meridional Overturning Circulation

Changes in the Atlantic Meridional Overturning Circulation, which have the potential to drive societally-important climate impacts, have traditionally been linked to the strength of deep water formation in the subpolar North Atlantic. Yet there is neither clear observational evidence nor agreement among models about how changes in deep water formation influence overturning. Here, we use data from a trans-basin mooring array (OSNAP-Overturning in the Subpolar North Atlantic Program) to show that winter convection during 2014-2018 in the interior basin had minimal impact on density changes in the deep western boundary currents in the subpolar basins. Contrary to previous modeling studies, we find no discernable relationship between western boundary changes and subpolar overturning variability over the observational time scales. Our results require a reconsideration of the notion of deep western boundary changes representing overturning characteristics, with implications for constraining the source of overturning variability within and downstream of the subpolar region.

Refugia under threat: Mass bleaching of coral assemblages in high-latitude eastern Australia

Environmental anomalies that trigger adverse physiological responses and mortality are occurring with increasing frequency due to climate change. At species' range peripheries, environmental anomalies are particularly concerning because species often exist at their environmental tolerance limits and may not be able to migrate to escape unfavourable conditions. Here, we investigated the bleaching response and mortality of 14 coral genera across high-latitude eastern Australia during a global heat stress event in 2016. We evaluated whether the severity of assemblage-scale and genus-level bleaching responses was associated with cumulative heat stress and/or local environmental history, including long-term mean temperatures during the hottest month of each year (SST_LTMAX ), and annual fluctuations in water temperature (SST_VAR ) and solar irradiance (PARZ_VAR ). The most severely-bleached genera included species that were either endemic to the region (Pocillopora aliciae) or rare in the tropics (e.g. Porites heronensis). Pocillopora spp., in particular, showed high rates of immediate mortality. Bleaching severity of Pocillopora was high where SST_LTMAX was low or PARZ_VAR was high, whereas bleaching severity of Porites was directly associated with cumulative heat stress. While many tropical Acropora species are extremely vulnerable to bleaching, the Acropora species common at high latitudes, such as A. glauca and A. solitaryensis, showed little incidence of bleaching and immediate mortality. Two other regionally-abundant genera, Goniastrea and Turbinaria, were also largely unaffected by the thermal anomaly. The severity of assemblage-scale bleaching responses was poorly explained by the environmental parameters we examined. Instead, the severity of assemblage-scale bleaching was associated with local differences in species abundance and taxon-specific bleaching responses. The marked taxonomic disparity in bleaching severity, coupled with high mortality of high-latitude endemics, point to climate-driven simplification of assemblage structures and progressive homogenisation of reef functions at these high-latitude locations.

Does the source of referral affect outcomes for paediatric testicular torsion?

INTRODUCTION

This single centre study retrospectively analysed the intraoperative findings relative to source of referral for emergency scrotal explorations performed in a tertiary level paediatric surgery department.

METHODS

All patients who underwent emergency scrotal exploration under the care of paediatric surgeons in our unit between April 2008 and April 2016 were identified. Clinical data were obtained from contemporaneous records.

RESULTS

Over the 8-year study period, 662 boys underwent emergency scrotal exploration: 6 (1%) were internal referrals, 294 (44%) attended our emergency department (ED) directly, 271 (41%) were referred from primary care and 91 (14%) were transferred from other hospitals. Excluding procedures in neonates, testicular torsion was present in 100 cases (15%). Testicular detorsion with bilateral 3-point testicular fixation was performed in 66 (66%) and orchidectomy with contralateral fixation in 34 (34%) where the torted testis was non-viable intraoperatively. The orchidectomy rate in the presence of torsion was 23% in ED referrals (12/52), 43% in primary care referrals (12/28) and 50% for transfers (10/20). The difference in rates between ED referrals and patients transferred from other hospitals was significant (p=0.026). There was no significant difference in median age between any of the groups (p=0.10).

CONCLUSIONS

Boys undergoing emergency scrotal exploration had a higher orchidectomy rate when transferred from other hospitals to our unit. This difference was statistically significant when compared with boys presenting directly to our ED. This supports advice from The Royal College of Surgeons of England for undertaking paediatric scrotal explorations in the presenting hospital when safe to do so rather than delaying the care of these patients by transferring them to a tertiary paediatric surgical unit.

Tracing the source of marine debris on the beaches of northern New South Wales, Australia: The Bottles on Beaches program

Identifying the source of marine plastic pollution accumulating on ocean beaches is often difficult as unidentifiable fragments of plastic usually predominate. In this study, we surveyed plastic bottles as a relatively identifiable subset of plastics on 30km of beach along a 200-km section of the north coast of New South Wales, Australia. Source and product type (contents) were determined using barcodes, inscriptions/embossing, or bottle shape and characteristics. Country of origin and product type could be determined for two-thirds of the 694 bottles found. Just over half (51%) of these were of domestic origin with the remainder dominated by bottles from China (24%) and south-east Asian countries (21%). As most of the foreign bottles lacked marine growth, and are unavailable for purchase in the region, passing ships are hypothesised as the primary source.

Synchronous laparoscopic-assisted percutaneous endoscopic gastrostomy and peritoneal dialysis catheter placement is a valid alternative to open surgery

OBJECTIVE

Gastrostomy feeding is frequently necessary in children receiving chronic peritoneal dialysis (PD). Synchronous laparoscopic-assisted placement of percutaneous endoscopic gastrostomy (PEG) and PD catheter has many potential advantages. This study investigates whether this technique is comparable to open placement.

METHODS

The notes of all patients over a 16-year time period were reviewed retrospectively. Peritonitis was defined as the presence of a white blood cell count > 100/mm(3) with at least 50% being polymorphonuclear leukocytes, and infection was defined as the presence of positive peritoneal cultures with peritonitis.

RESULTS

Ten patients received primary laparoscopic-assisted PEG and PD catheter insertion (LAP) and 23 patients open gastrostomy and PD catheter (OPEN). PD catheter survival was median 12 months in the LAP group and 17 months in the OPEN group. Peritonitis and infection rates per catheter-year were 0.89 and 0.7 LAP and 0.59 and 0.5 OPEN. The risk of peritonitis and infection was not related to method of placement.

CONCLUSIONS

There were no statistically significant differences in outcomes between the two groups. We conclude that laparoscopic-assisted synchronous PD and PEG catheter insertion is safe and effective.

46XY girls: the importance of careful newborn examination

STUDY OBJECTIVE

To understand the timing and factors affecting diagnosis of phenotypically female 46XY children.

DESIGN, SETTING, AND PARTICIPANTS

We studied all phenotypically female 46XY children who attended our multidisciplinary disorders of sexual differentiation (DSD) clinic in Nottingham England in a 3-year period since its inception. Case notes from a prospectively maintained database were reviewed and data were analyzed on the age at presentation, family history, findings on genital examination, and underlying endocrine abnormality.

RESULTS

Eleven children were studied, all of whom were being raised as girls. The median age of presentation was 18 months (range birth-15 years). Although the newborn examination detected the possibility of DSD in only 3 cases; 10 of 11 children had at least one significant abnormality in their external genitalia at presentation.

CONCLUSION

Careful neonatal genital examination can identify children with DSD. However, not all children with these conditions are identified early. Early diagnosis, when possible, is important, as it has the potential to make the management of this difficult condition more straightforward.

Is regional anaesthesia better than general anaesthesia for caesarean section?

The Royal College of Anaesthetists have set the standard that 85% of emergency caesarean sections should be carried out under regional anaesthesia. Reducing the frequency of caesarean sections carried out under general anaesthesia may serve to reduce maternal morbidity and mortality, which has been shown over recent years. A retrospective audit was carried out at a tertiary referral centre investigating the mode of anaesthesia and fetal outcome after emergency caesarean section. The proportion carried out under regional anaesthesia was less than recommended. Despite a longer time taken to induce anaesthesia there was no increase in adverse fetal outcome, supporting the use of regional anaesthesia wherever possible to keep maternal complications to a minimum.

Appendicular colic and the non-inflamed appendix: fact or fiction?

AIMS

Appendicoliths cause acute appendicitis and appendicular perforation. Do appendicoliths cause acute abdominal pain in the absence of acute appendicitis?

METHODS

A retrospective observational study was undertaken of histology reports of all appendicectomy specimens from children < 16 years of age between January 1995 and December 2001. Specimens were categorised as perforated or uncomplicated acute appendicitis, non-inflamed, and "incidental" (removed during abdominal surgery for other indications). The presence of an appendicolith was noted. Clinical details were supplemented by selected case note review. Specimens in which the diagnosis of appendicitis or the presence of an appendicolith were not clearly defined (n = 20) were reviewed by an experienced, independent pathologist.

RESULTS

601 consecutive appendicectomy reports were analysed. The mean age of the study population was 9 years (range 1 day - 15.9 years) and there were 357 boys. An appendicolith was identified in 31/118 (26%) cases of perforated appendicitis, 60/352 (17%) cases of uncomplicated appendicitis, 12/59 (20%) cases of non-inflamed appendices, and only 1/72 (1%) cases of incidental appendicectomies. All patients with an appendicolith in the non-inflamed appendix group had presented with acute abdominal pain mimicking acute appendicitis. The frequency of an appendicolith in perforated appendicitis was significantly greater than in uncomplicated acute appendicitis (chi (2) = 4.8, 1 df, p < 0.05). There was no significant difference in the frequency of an appendicolith between non-inflamed appendices and acute appendicitis (either perforated or intact). Appendicoliths were rarely found in incidental appendicectomies, but these patients were younger. The frequency of appendicoliths in non-inflamed appendices was much greater than that expected from published autopsy data.

CONCLUSION

Appendicoliths may cause acute abdominal pain that mimics acute appendicitis.

Handlebar hernia masquerading as an inguinal haematoma

We report a child who sustained a traumatic hernia of the lower abdominal wall after being thrown forward against the handlebar of his bicycle. This is a rare injury in children, and the clinical features mimic an inguinal haematoma. Suspicion should be raised by the immediate appearance of a mass above the inguinal canal following groin injury, particularly if the swelling then disappears with the patient supine.

Heteronuclear 2D-correlations in a uniformly [13C, 15N] labeled membrane-protein complex at ultra-high magnetic fields

One- and two-dimensional solid-state NMR experiments on a uniformly labeled intrinsic membrane-protein complex at ultra-high magnetic fields are presented. Two-dimensional backbone and side-chain correlations for a [U-13C, 15N] labeled version of the LH2 light-harvesting complex indicate significant resolution at low temperatures and under Magic Angle Spinning. Tentative assignments of some of the observed correlations are presented and attributed to the alpha-helical segments of the protein, mostly found in the membrane interior.

Oral probiotics can resolve urogenital infections

We report the first clinical evidence that probiotic lactobacilli can be delivered to the vagina following oral intake. In 10 women with a history of recurrent yeast vaginitis, bacterial vaginosis (BV) and urinary tract infections, strains Lactobacillus rhamnosus GR-1 and Lactobacillus fermentum RC-14 suspended in skim milk and given twice daily for 14 days, were recovered from the vagina and identified by morphology and molecular typing within 1 week of commencement of therapy. In six cases of asymptomatic BV or intermediate BV (based upon Nugent scoring) was resolved within 1 week of therapy.

Development of a homogeneous MAP kinase reporter gene screen for the identification of agonists and antagonists at the CXCR1 chemokine receptor

Agonist activity at G protein-coupled receptors (GPCRs) that regulate heterotrimeric G proteins of the Galpha(i/o) or Galpha(q) families has been shown to result in activation of the mitogen-activated protein (MAP) kinase cascade. To facilitate compound screening for these classes of GPCR, we have developed a reporter gene that detects the activation of the ternary complex transcription factor Sap1a following MAP kinase activation. In contrast to other reporter gene assays for Galpha(i/o)-coupled GPCRs, the MAP kinase reporter generates an increase in signal in the presence of agonist. The reporter gene has been transfected into Chinese hamster ovary cells to generate a "host" reporter gene-containing cell line. The Galpha(i)-coupled human CXCR1 chemokine receptor was subsequently transfected into this cell line in order to develop a 384-well format screen for both agonists and antagonists of this receptor. Agonists activated the reporter gene with the expected rank order of potency and with similar concentration dependence as seen with the regulation of other signal transduction cascades in mammalian cells: interleukin-8 (IL-8) (pEC(50) = 7.0 +/- 0.1) > GCP-2 (pEC(50) = 6.3 +/- 0.1) > NAP-2 (pEC(50) < 6). CXCR1-mediated activation of MAP kinase was inhibited by pertussis toxin and the MEK inhibitor PD98059, demonstrating that receptor activation of MAP kinase is due to pertussis toxin-sensitive Galpha(i/o)-family G proteins to cause the activation of MEK kinase. Using the 384-well format, assay performance was unaffected by solvent concentrations of 0.5% ethanol, 0.15% glycerol, or 1% DMSO. Signal crosstalk between adjacent wells was less than 1%. The assay exhibited a Z factor of 0.53 and a coefficient of variation of response to repeated application of IL-8 (100 nM) of 15.9%.

Age-based rationing in the allocation of health care

OBJECTIVES

This article seeks to review debates about age-based rationing in health care.

METHODS

The article identifies four different levels (or types) of decision-making in health resources allocation--societal, strategic, programmatic, and clinical--and assesses how the issues of rationing vary in relation to each level.

RESULTS

The article concludes that rationing is least defensible at the clinical level, where it is also most covert. The role of rationing at other levels is more defensible when based on grounds of cost-effectiveness rather than equity. The article emphasizes the importance of fairness in health allocation and suggests that efficiency criteria need to be considered in that context.

DISCUSSION

The article suggests that rationing is most problematic where it is least overt. This raises further questions about how rationing can be made more explicit at different levels of decision making.

An RMO in Sierra Leone

We enjoyed a very low level of DNBI during our deployment and no soldier had to be returned to the UK on medical grounds. None of the measures employed to reduce disease were complicated or new and most were merely common sense. The implementation does however require firm conviction by the chain of command. As in virtually all conflicts the greatest threat to a deployed force continues to be disease.

Pharmacological characterization of human recombinant melatonin mt(1) and MT(2) receptors

We have pharmacologically characterized recombinant human mt(1) and MT(2) receptors, stably expressed in Chinese hamster ovary cells (CHO-mt(1) and CHO-MT(2)), by measurement of [(3)H]-melatonin binding and forskolin-stimulated cyclic AMP (cAMP) production. [3H]-melatonin bound to mt(1) and MT(2) receptors with pK(D) values of 9.89 and 9.56 and B(max) values of 1.20 and 0.82 pmol mg(-1) protein, respectively. Whilst most melatonin receptor agonists had similar affinities for mt(1) and MT(2) receptors, a number of putative antagonists had substantially higher affinities for MT(2) receptors, including luzindole (11 fold), GR128107 (23 fold) and 4-P-PDOT (61 fold). In both CHO-mt(1) and CHO-MT(2) cells, melatonin inhibited forskolin-stimulated accumulation of cyclic AMP in a concentration-dependent manner (pIC(50) 9.53 and 9.74, respectively) causing 83 and 64% inhibition of cyclic AMP production at 100 nM, respectively. The potencies of a range of melatonin receptor agonists were determined. At MT(2) receptors, melatonin, 2-iodomelatonin and 6-chloromelatonin were essentially equipotent, whilst at the mt(1) receptor these agonists gave the rank order of potency of 2-iodomelatonin>melatonin>6-chloromelatonin. In both CHO-mt(1) and CHO-MT(2) cells, melatonin-induced inhibition of forskolin-stimulated cyclic AMP production was antagonized in a concentration-dependent manner by the melatonin receptor antagonist luzindole, with pA(2) values of 5.75 and 7.64, respectively. Melatonin-mediated responses were abolished by pre-treatment of cells with pertussis toxin, consistent with activation of G(i)/G(o) G-proteins. This is the first report of the use of [(3)H]-melatonin for the characterization of recombinant mt(1) and MT(2) receptors. Our results demonstrate that these receptor subtypes have distinct pharmacological profiles.

Growth response to rhIGF-I 80 microg/kg twice daily in children with growth hormone insensitivity syndrome: relationship to severity of clinical phenotype

BACKGROUND

rhIGF-I has been used effectively to promote growth in growth hormone insensitivity syndrome (GHIS) in doses ranging from 40 microg/kg twice daily to 150-200 microg/kg once daily. It appears that the dose of 80 microg/kg twice daily s.c. may induce an equivalent response to higher doses with less side-effects.

OBJECTIVE

To study the efficacy and safety of rhIGF-I, 80 microg/kg twice daily s.c., in children with GHIS and to analyse the relationship of growth response to severity of phenotype.

PATIENTS AND DESIGN

Eleven prepubertal children (3 females, 8 males) with GHIS; basal GH > 2.5 microg/l, IGF-I < 50 microg/l, IGFBP-3 < - 2SD; were treated with IGF-I 80 microg/kg twice daily in a multi-centre study. The baseline characteristics of these patients were as follows (mean +/- SD): age, 7.5 +/- 2.5 years (range, 2.5-11.7 years), bone age (Tanner-Whitehouse - 2 RUS), 5.2 +/- 2.4 years (range, 2.3-9.1 years), mean height SDS, - 5.6 +/- 1.6 (range, - 3.1 to - 8.1), height velocity (HV), 3.1 +/- 1.1 cm/year (range, 1.9-4.9 cm/year). Height, HV, weight, skinfold thickness, puberty stage and bone age were measured at baseline and 6 monthly for 2 years.

RESULTS

During the first 12 months of IGF-I therapy, the mean +/- SD HV was 7.7 +/- 1.6 cm/year (range, 6.1-11.2 cm/year), the mean +/- SD increase in HV was 4.7 +/- 2.1 cm/year (range, 1.7-8.8 cm/year) and the mean +/- SD progression of bone age was 1.9 +/- 1.0 years (range, 0.8-3.8 years). Pre-treatment height SDS at the start of IGF-I therapy correlated positively with pretreatment serum IGFBP-3 SDS levels (r = 0.85; P < 0.01). There was a significant inverse correlation between gain in height SDS and pre-treatment height SDS (r = - 0.76; P < 0.01). During the 2nd 12 months of therapy, mean HV was 7.0 +/- 3.4 cm/year (range 3.8-12.4) change in height SDS from 12 to 24 months was not significantly correlated with pre-treatment height SDS. Subscapular skinfold SDS decreased significantly (P < 0.05) during the study period, whereas there was no significant change in body mass index and triceps skinfold thickness SDS. Adverse events reported in the patient group included headache (2 patients), hypoglycaemia (2 patients), papilloedema (transient, 1 patient), lipohypertrophy (5 patients) and tonsillectomy/adenoidectomy (2 patients).

CONCLUSION

This study reveals that IGF-I treatment at a dose of 80 microg/kg twice daily is effective in patients with growth hormone insensitivity syndrome. During the first 12 months of therapy, there was a significant inverse relationship between growth response to IGF-I therapy and the severity of the phenotype of growth hormone insensitivity syndrome, as measured by height SDS, at the start of therapy. Patients with a more severe clinical phenotype of growth hormone insensitivity syndrome, who also had most severe IGFBP-3 deficiency, responded better than those who were more mildly affected. An analogous situation has been shown to be the case in GH-deficient patients treated with hGH.

Calcium sensing properties of the GABA(B) receptor

The GABA(B) receptor has been shown to consist of a heterodimer of two related 7-transmembrane receptors GABAB-R1 and GABA(B)-R2. These receptors share close homology to the Ca2+-sensing receptor and also to the metabotropic glutamate receptors, which have also been shown to respond to extracellular calcium. We show here that the GABA(B) receptor also has Ca2+ sensing properties. Ca2+ (0.001-1 mM) potentiated the GABA stimulation of [35S]GTPgammaS binding in membranes prepared from CHO cells stably expressing the GABA(B)-R1/R2 heterodimer. The GABA EC50 was reduced from 72 to 7.7 microM by addition of 1 mM Ca2+, with no change in the maximum response. A similar effect was observed in membranes from rat brain cortex. Ca2+ also potentiated GABA inhibition of forskolin-stimulated cAMP levels in the CHO cells and enhanced coupling to GIRK K+ channels in Xenopus oocytes. Other divalent cations were ineffective. The effects of Ca2+ were found to be agonist dependent with baclofen having a reduced sensitivity compared to GABA. Calcium appears to act allosterically to enhance GABA responses at the GABA(B) receptor, however, unlike the Ca2+-sensing receptor and some of the mGluR family, Ca2+ does not act as a ligand in its own right.

A bioluminescent assay for agonist activity at potentially any G-protein-coupled receptor

Transient expression of apoaequorin in Chinese hamster ovary (CHO) cells and reconstitution with the co-factor coelenterazine resulted in a large, concentration-dependent agonist-mediated luminescent response following cotransfection with the endothelin ETA, angiotensin ATII, thyrotropin-releasing hormone (TRH), and neurokinin NK1 receptors, all of which interact pre-dominantly with the G alpha q-like phosphoinositidase-linked G-proteins. A substantially greater luminescence was obtained with mitochondrially targeted apoaequorin compared to cytoplasmically expressed apoaequorin. To generate a system amenable for the study of agonist activity at virtually any G-protein-coupled receptor the alpha subunit of the receptor promiscuous G-protein G alpha 16 was either transiently or stably expressed in CHO cells together with apoaequorin. In cells expressing G alpha 16, but not in its absence, agonists at a series of receptors which normally interact with either G alpha s or G alpha i were now able to cause a luminescent response from mitochondrially targeted apoaequorin. In the case of the A1 adenosine receptor, this response was clearly a result of activation of G alpha 16 and not a consequence of the release of the G alpha i-associated beta/gamma complex, as the luminescent response was unaffected by pertussis toxin treatment of the cells, whereas agonist-mediated inhibition of adenylyl cyclase activity was attenuated. These studies describe the use of coexpressed apoaequorin as a reporter for G-protein-coupled receptor-mediated calcium signaling. Furthermore, coexpression of G alpha 16 and apoaequorin provides a basis for a generic mammalian cell microplate assay for the assessment of agonist action at virtually any G-protein-coupled receptor, including orphan receptors for which the physiological signal transduction mechanism may be unknown.

A quality assurance scheme for the Kleihauer test: the Scottish experience 1988-1996

This report describes the experience gained in the last 8 years of implementing and administering a Quality Assurance Scheme dedicated to improving the reliability of Kleihauer test results in Scotland. Initially the five transfusion centres in Scotland were the only participants, but since 1992 all 15 hospital laboratories in Scotland performing the Kleihauer test to ensure an adequate dose of anti-D is administered to Rh-negative women, at risk of developing allo anti-D, have joined this voluntary scheme. As a result of the standardization of technical methods, improvement in reporting of QA results has been observed since 1994.

In vivo expression of inducible nitric oxide synthase in experimentally induced neurologic diseases

The purpose of this study was to investigate the induction of inducible nitric oxide synthase (iNOS) mRNA in the brain tissue of rats and mice under the following experimental conditions: in rats infected with borna disease virus and rabies virus, in mice infected with herpes simplex virus, and in rats after the induction of experimental allergic encephalitis. The results showed that iNOS mRNA, normally nondetectable in the brain, was present in animals after viral infection or after induction of experimental allergic encephalitis. The induction of iNOS mRNA coincided with the severity of clinical signs and in some cases with the presence of inflammatory cells in the brain. The results indicate that nitric oxide produced by cells induced by iNOS may be the toxic factor accounting for cell damage and this may open the door to approaches to the study of the pathogenesis of neurological diseases.

MK: a pluripotential embryonic stem-cell-derived neuroregulatory factor

MK is a gene encoding a secreted heparin-binding polypeptide originally isolated by differential screening for genes induced by retinoic acid (RA) in HM-1 embryonal carcinoma cells. Here we report that MK is expressed at high levels in both embryonal carcinoma and pluripotential embryonic stem cells and their differentiated derivatives. MK expression in these cell types is unaffected by the presence or absence of RA. Recombinant MK protein (rMK) was produced by transient expression in COS cells and purified by heparin affinity chromatography. rMK is a weak mitogen for 10T1/2 fibroblast cells but inactive as a mitogen for Swiss 3T3 fibroblasts. rMK is a potent mitogen for neurectodermal precursor cell types generated by treatment of 1009 EC cells with RA but has no mitogenic or neurotrophic effects on more mature 1009-derived neuronal cell types. rMK is active as an in vitro neurotrophic factor for E12 chick sympathetic neurons and its activity is markedly potentiated by binding the factor to tissue-culture plastic in the presence of heparin. Stable 10T1/2 cells lines have been established which express MK. These cells do not exhibit any overt evidence of cell transformation but extracellular matrix preparations derived from these cells are a potent source of MK biological activity. It is concluded that MK is a multifunctional neuroregulatory molecule whose biological activity depends upon association with components of the extracellular matrix.

X chromosome inactivation in fibroblasts of mentally retarded female carriers of the fragile site Xq27.3: application of the probe M27 beta to evaluate X inactivation status

Over 30% of female carriers of the fragile X [fra(X)] syndrome are clinically affected. A nonrandom X chromosome inactivation in these cases could be a plausible explanation. A review of previous studies addressing this question showed inconclusive results; thus, we analysed the X inactivation pattern in fibroblasts of 4 unrelated, mentally retarded fra(X) carriers with a high expression of the fragile site Xq27.3. Using Southern analysis with a highly polymorphic probe M27 beta that recognizes methylation differences between the active and inactive X chromosome we found a 50/50 inactivation pattern in 2 cases and skewed patterns in the other 2. As biased patterns were also observed in control females we conclude that at present no evidence exists for a nonrandom X chromosome inactivation in the fra(X) syndrome in females.

The effectiveness of bacillus Calmette-Guérin (BCG) vaccination against tuberculosis. A case-control study in Treaty Indians, Alberta, Canada

Bacillus Calmette-Guérin (BCG) vaccination against tuberculosis has been used around the world for 60 years, yet its efficacy in large, controlled prospective studies is inconsistent. The factors influencing BCG protection include variation in immunogenic potential, background exposure to environmental mycobacteria, and differences in host response to vaccine. As a means of addressing regional differences in protection, case-control studies provide a relatively inexpensive, rapid means of assessing regional vaccine effects. Treaty Indian cases (n = 160) resident in Alberta, Canada, presenting during a 5-year period (1975-1979) were individually matched for age, sex, and Band with two nontuberculous controls. A 57 percent protection by BCG vaccination was demonstrated. These results support the usefulness of case-control studies and their importance in planning tuberculosis control programs.

Molecular characterization of human X/Y translocations suggests their aetiology through aberrant exchange between homologous sequences on Xp and Yq

Several DNA sequences from two homologous regions, localized on the distal part of the human X chromosome short arm and on the long arm of the Y chromosome, have been hybridized to DNAs from seven human-rodent hybrids containing human X; Y translocation chromosomes. Molecular characterization of the translocated chromosomes has revealed, in all but one case, transfer of the Y cluster of sequences and complete deletion of the corresponding X-chromosomal sequences. The possible role of X/Y homology in the aetiology of X; Y translocations is proposed.

Linkage studies do not confirm the cytogenetic location of incontinentia pigmenti on Xp11

Linkage studies have been performed in 5 incontinentia pigmenti (IP) families totaling 29 potentially informative meioses. Ten probes of the Xp arm were used, six of them were precisely localized on the X chromosome, using hamster X human somatic cell hybrids containing a broken X chromosome derived from an incontinentia pigmenti patient carrying an X;9 translocation [46,XX,t(X;9)(p11.21;q34)]. The following order for probes is proposed: pter - (DXS7, DXS146, DXS255) - IP1 - (DXS14, DXS90) - DXS106 - qter. The negative lod scores obtained exclude the possibility that in the families studied, the gene for IP is located in Xp11 or in the major part of the Xp arm.

Isolation and characterization of a steroid sulfatase cDNA clone: genomic deletions in patients with X-chromosome-linked ichthyosis

We have isolated several cDNA clones from a lambda gt11 expression library by screening with antibodies prepared against the microsomal enzyme steroid sulfatase, which is deficient in classical X-chromosome-linked ichthyosis patients. One of these clones (p422) has been assigned by mapping with a somatic cell hybrid panel and by in situ hybridization to Xp22.3. Clone p422 therefore has a coincident localization with the previously identified locus for steroid sulfatase expression in the region of the X chromosome escaping from inactivation. Twelve steroid sulfatase-deficient patients, including eight cases of classical ichthyosis, were found to be deleted for genomic sequences detected by the clone.

Localisation of Y chromosome sequences in normal and 'XX' males

Three unique sequences derived from the Y chromosome have been mapped within the human genome. A Y specific sequence DYS20 is localised to Yq11.2. DXYS25 and DXYS27 are both X-Y homologous sequences which map to the Y short arm and to Xq21. DXYS25 maps more distally than DXYS27, on the Y short arm and on the X long arm. Y specific restriction fragments for these two sequences are shown to be present in the genome of two XX males, and an aberrant signal for DXYS25 is demonstrated at the tip of an X chromosome short arm in one XX male by in situ hybridisation. The implications of these findings for the location of the testis determining factor are discussed.

Identification of incomplete coding sequences for steroid sulphatase on the human Y chromosome: evidence for an ancestral pseudoautosomal gene?

A cDNA clone (p422) containing about 200 bp of coding sequences for steroid sulphatase (STS) has been isolated from a λgt 11 expression library by antibody screening and has been assigned by mapping with a somatic cell hybrid panel and by in situ hybridization to Xp22.3; a localization coincident with the previously identified locus for STS expression. Although no significant hybridization of this clone to the Y chromosome was observed, p422 has been used to isolate a longer cDNA clone and genomic sequences which do recognize Y-specific restriction fragments. An abbreviated STS gene has been localized to Yq11.2. The coding sequences for the human enzyme shows little homology to sequences in mice.

Bacterial meningitis in Johannesburg--1980-1982

A 2-year retrospective study of aetiology, age distribution, seasonal variation and antimicrobial sensitivity patterns of bacteria isolated from patients with meningitis in five Johannesburg hospitals for White, Black, Coloured and Asian patients was performed. Neisseria meningitidis was isolated most frequently, followed by Streptococcus pneumoniae, Haemophilus influenzae, Escherichia coli and Streptococcus group B. In the Black population 73% of the meningococcal infections occurred in patients over 3 years of age, and the majority of these infections were caused by serogroup A organisms. Virtually all (93%) of the H. influenzae infections occurred in children of less than 3 years of age. Of the isolates tested, 16% of the meningococci, 4,5% of the H. influenzae and 47% of the pneumococci were resistant to sulphadiazine, ampicillin and penicillin respectively.

The internal organization of the varicella-zoster virus genome

DNA was extracted from varicella-zoster (VZ) virions prepared in sucrose gradients. Thirty-eight molecules examined by electron microscopy were found to have a mean length of 46.7 micrometers. Examination of self-annealed VZV DNA molecules revealed that the virus genome was composed of a unique linear large sequence with a mol. wt. of 74.4 X 10(6) to 78.4 X 10(6), and a unique short sequence of mol. wt. approx. 9.8 X 10(6) flanked by inverted repeat sequences of 4.7 X 10(6) mol. wt.

Extraction of cell-associated varicella-zoster virus DNA with triton X-100-NaCl

Varicella-zoster virus (VZV) DNA was extracted from infected cells with 0.25% Triton X-100-0.2 M NaCl and purified by isopycnic centrifugation in CsCl. In each of eight experiments, 1.8-9.8 micrograms VZV DNA was obtained from 107 infected cells. The VZV DNA obtained by this procedure had a molecular weight of 88-100 x 106 as determined by sucrose gradient sedimentation and electron microscopy, and cleavage patterns after digestion with four restriction enzymes that corresponded to patterns previously described with six strains of VZV; the pattern of BamHI-cleaved Triton-NaCl-extracted VZV DNA was identical to the pattern seen after DNA extraction from virions. These studies expand the usefulness of Triton X-100-NaCl for extraction of large molecular weight viral DNA from a system where considerable cell-free virus is produced (Pignatti et al., 1979, Virology 93, 260) to a system known for its marked cell association.

Adenovirus type 2 late mRNA's: structural evidence for 3'-coterminal species

Adenovirus type 2-infected HeLa cells were labeled with 32PO4 during the period 14 to 17 h postinfection. Viral mRNA's with polyadenylic acid were isolated by polyuridylic acid Sepharose chromatography and fractionated according to size by electrophoresis through an acrylamide-agarose slab gel. Messenger bands were eluted and partially degraded with alkali. RNA fragments from each band that contain polyadenylic acid were isolated by polyuridylic acid Sepharose chromatography and fingerprinted two-dimensionally after T1 RNase digestion. Three bands, with mobilities of approximately 26S, 21S, and 18S, shared two large characteristic T1 oligonucleotides in common in the fingerprints of their 3'-terminal sequences. These oligonucleotides were mapped with a Hpa II restriction fragment of adenovirus type 2 DNA with coordinates 49-50.2. We conclude that the three mRNA's are coterminal in sequence at their 3' ends and overlap at internal positions. Implications for the protein-coding potential of these mRNA's and the mechanisms of adenovirus tyep 2 late RNA processing are discussed.