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Biomedical subjects

S Jenkins

Publications and source records attributed to S Jenkins.

At least 19 recordsLinked to original sources

Comparison of image quality, diagnostic confidence and interobserver variability in contrast enhanced MR angiography and 2D time of flight angiography in evaluation of carotid stenosis.

The aim of this study was to compare image quality, level of diagnostic confidence and interobserver agreement in assessment of carotid stenosis with contrast enhanced MR angiography (CE MRA) in comparison with 2D time of flight MR angiography (2D TOF MRA). 60 carotid arteries in 30 patients were examined by three observers. Image quality and diagnostic confidence were assessed on the basis of a visual analogue scale. Interobserver variability was assessed with the help of intraclass correlation coefficient. Median values on the visual analogue scale for image quality and diagnostic confidence were higher for CE MRA compared with 2D TOF MRA for all three observers. Higher intraclass correlation values were recorded for interobserver variability for CE MRA compared with 2D TOF MRA both for visual estimation of carotid stenosis as well as for measurement of carotid stenosis on the basis of North American Symptomatic Carotid Endarterectomy Trial (NASCET) and European Carotid Surgery Trial (ECST) criteria. CE MRA provides better image quality, higher level of diagnostic confidence and more interobserver agreement compared with 2D TOF MRA.

Artifacts↗

Effects of maternal betamethasone administration on fetal and maternal blood pressure and heart rate in the baboon at 0.7 of gestation.

OBJECTIVE: We sought to determine the effects of the intramuscular maternal administration of betamethasone to the pregnant baboon at 0.7 of gestation on fetal blood pressure and heart rate. STUDY DESIGN: We treated pregnant baboons at 0.7 of gestation with intramuscular betamethasone (n = 4), at a weight-adjusted dose equivalent to the daily dose administered to women in preterm labor or with saline solution (n = 5). Four injections were given at 12-hour intervals. Fetal and maternal blood pressure and heart rate were recorded continuously. Within-group differences and between-group differences were analyzed with repeated measures analysis of variance. RESULTS: Fetal blood pressure increased significantly after betamethasone treatment. Fetal heart rate, maternal blood pressure, and heart rate did not change. CONCLUSION: Exposure of the developing primate fetus to exogenous glucocorticoid at 0.7 of gestation elevates fetal blood pressure. These findings confirm and extend the observations in the fetal sheep. Further studies are needed to evaluate the mechanisms that are involved and possible long-term consequences of these cardiovascular effects of antenatal glucocorticoid exposure in the fetal primate.

Animals↗

In vitro activities of newer quinolones against bacteroides group organisms.

The activities of BMS-284576, clinafloxacin, moxifloxacin, sitafloxacin, trovafloxacin, imipenem, cefoxitin, and clindamycin against 589 Bacteroides fragilis group isolates were determined. The activity of BMS-284576 was comparable to that of trovafloxacin. Sitafloxacin and clinafloxacin were the most active quinolones, and moxifloxacin was the least active. B. fragilis was the most susceptible of the species, and Bacteroides vulgatus was the most resistant. Association of specific antibiotic resistance with Bacteroides species was noted for all quinolones.

Anti-Infective Agents↗

Cervical dystonia severity scale reliability study.

Cervical dystonia (CD) is characterized by sustained contractions of the neck musculature, resulting in abnormal head postures. The Cervical Dystonia Severity Scale (CDSS) was developed to provide a reliable measure of treatment response in patients with CD. The CDSS uses a protractor and wall chart to rate the severity of the head's deviation from neutral in each of three planes of motion (rotation, laterocollis, anterocollis/retrocollis), which is then scored in 5 degree intervals (1 degree to 5 degrees deviation = 1; 86 degree to 90 degrees deviation = 18). To test the reliability of the CDSS, four centers, each with two independent examiners, evaluated 42 patients with CD. At each site, each of the two examiners used the CDSS to evaluate the head position of each patient twice, on the same day, for a total of four evaluations. The kappa value for intra-examiner agreement was 0.94 (95% confidence limit of 0.900-0.972), indicating excellent intra-examiner reliability. The kappa value for interexaminer reliability was 0.79 for the first evaluation and 0.86 for the second evaluation (95% confidence limits of 0.668-0.920 and 0.790-0.920) indicating excellent interexaminer reliability. Thus, the CDSS was highly reliable in both intra-examiner and interexaminer scoring comparisons.

Adult↗

Manual hyperinflation: consistency and modification of the technique by physiotherapists.

BACKGROUND AND PURPOSE: The present study aimed to evaluate the consistency with which physiotherapists apply manual hyperinflation to a test lung using the Air-Viva-2 or Mapleson-B resuscitation circuit, and their ability to modify the technique as pulmonary characteristics change. METHOD: A quasi-experimental, randomized, repeated-measures design was used to study 16 volunteer physiotherapists performing manual hyperinflation to a test lung simulating three clinical situations. Each subject applied manual hyperinflation to the test lung for each simulation three times in one day using the resuscitation circuit that they would normally use in their clinical practice. Eight subjects used the Air-Viva-2 circuit and eight used the Mapleson-B circuit. Measurements of tidal volume (Vp), peak airway pressure (Paw) and fraction of delivered oxygen (FDO2) were recorded during each testing period. Inflation rate and minute volume were calculated. RESULTS: As compliance decreased and airway resistance increased, VT decreased and Paw increased. Of the eight subjects using the Air-Viva-2 circuit, only three subjects delivered greater than 0.80 FDO2. All subjects using the Mapleson-B circuit delivered greater than 0.85 FDO2. CONCLUSIONS: Subjects demonstrated good consistency in the application of manual hyperinflation for all three simulations and modified their technique appropriately as simulated pulmonary characteristics changed.

Female↗

A randomized controlled trial comparing periodic mask CPAP with physiotherapy after abdominal surgery.

BACKGROUND AND PURPOSE: Physiotherapists use a variety of techniques aimed at improving lung volumes and secretion clearance in patients after surgery. Periodic continuous positive airway pressure (PCPAP) is used to treat patients following elective upper abdominal surgery. However, the optimal method of application has not been identified, more specifically, the dosage of application of PCPAP. The present randomized controlled trial compared the effects of two dosages of PCPAP application and 'traditional' physiotherapy upon functional residual capacity (FRC), vital capacity (VC), oxyhaemoglobin saturation (SpO2), incidence of post-operative pulmonary complications and length of stay with a control group receiving 'traditional' physiotherapy only. METHOD: Fifty-seven subjects were randomly allocated to one of three groups. All groups received 'traditional' physiotherapy twice daily for a minimum of three post-operative days. In addition, two groups received PCPAP for 15 or 30 minutes, four times per day, for three days. RESULTS: Fifty subjects (39 male; 11 female) completed the study. There were no significant differences in any variables between the three groups. The overall incidence of post-operative pulmonary complications was 22% in the control group, 11% and 6% in the PCPAP 15-minute and PCPAP 30-minute groups, respectively. Length of hospital stay was not significantly different between the groups but for subjects who developed post-operative pulmonary complications, the length of stay was significantly greater (Z = -2.32; p = 0.021). CONCLUSIONS: The addition of PCPAP to a traditional physiotherapy post-operative treatment regimen after upper abdominal surgery did not significantly affect physiological or clinical outcomes.

Abdomen↗

Cannabinoidergic and opioidergic inhibition of spinal reflexes in the decerebrated, spinalized rabbit.

The present experiments were designed to investigate the role(s) of cannabinoid receptors in modulating transmission in the sural-medial gastrocnemius withdrawal reflex of the decerebrated, spinalized rabbit and how, if present, cannabinoid-mediated control might interact with opioid-mediated inhibitions known to impinge on this reflex pathway. The selective CB(1) receptor antagonist SR 141716A enhanced reflexes by a factor of two after a cumulative dose of 100 nmol kg(-1) i.v., but had no effect on the endogenous opioid-mediated inhibition generated by repetitive electrical stimulation of the common peroneal nerve, or on the suppression of reflexes caused by i.v. administration of the synthetic opioid fentanyl. Given at a dose of 10 nmol kg(-1) i.v., the potent, CB(1)--CB(2) cannabinoid receptor agonist HU 210 inhibited medial gastrocnemius reflexes to approximately 30% of controls and significantly decreased both heart rate and blood pressure, but did not alter the inhibition of reflexes resulting from common peroneal nerve stimulation or i.v. fentanyl. The effects of HU 210 were reversed by SR 141716A. HU 210 was just as effective in inhibiting reflexes in the presence of the opioid antagonist naloxone (5 micromol kg(-1)) as it was in untreated animals. The data show that cannabinoids, acting through CB(1) receptors, are inhibitory in rabbit spinal cord and that there appears to be some endogenous cannabinoid tone under the conditions of the present experiments. The evidence of this study is that the inhibitory effects of opioids and cannabinoids in rabbit spinal cord are completely independent of each other, and are additive rather than synergistic.

Animals↗

Fungal infection of the diabetic foot: two distinct syndromes.

AIMS: Fungal infection of diabetic foot ulcers has not been described. We analysed the features of 17 patients with diabetic foot ulcers probably infected with fungi. METHODS: Seventeen patients were identified with clinically infected foot ulcers, (i) which had failed to heal despite prolonged antibiotic therapy and intensive podiatric care, (ii) from which Candida spp. was isolated or hyphae +/- yeasts were visualized in material from ulcers or surrounding skin. RESULTS: Multiple ulcers arising simultaneously were present in 10 patients (59%), preceded by blistering in seven cases. Single ulcers with markedly ulcerated margins were present in seven (41%) patients and were preceded by blisters in two. All 17 cases had neuropathy and 15 (88%) had severe peripheral vascular disease. All ulcers responded to antifungal therapy. CONCLUSIONS: Candida spp. is associated with two distinctive patterns of protracted ulceration in diabetic feet which improve following systemic antifungal therapy. Diabet. Med. 18, 567-572 (2001)

Adult↗

Long-term neurobehavioral outcomes in children with neuroblastoma and opsoclonus-myoclonus-ataxia syndrome: relationship to MRI findings and anti-neuronal antibodies.

OBJECTIVES: Opsoclonus-myoclonus-ataxia (OMA) syndrome affects 2% to 3% of patients with neuroblastoma. This study examined relationships between long-term neurobehavioral outcomes and potential biologic markers of OMA, including chronic changes on magnetic resonance imaging (MRI) brain scanning and prevalence of late antineuronal antibodies. STUDY DESIGN: Children with neuroblastoma and OMA were identified through medical record review of patients treated at the University of California at San Francisco Medical Center from 1979 to 1999. Eleven patients with a mean follow-up time of 7.6 years underwent standard neurologic, neurocognitive, developmental/behavioral, and academic assessments. Consenting patients underwent MRI brain scanning and a blood draw. Sera were analyzed for the presence of antineuronal immunoreactivity. RESULTS: Two (18%) patients had no observed neurologic abnormalities, 7 (64%) demonstrated mild deficits, and 2 (18%) had severe neurologic deficits. However, on neurocognitive, behavioral, and academic assessments, 6 (55%) children performed within the average range, 1 (9%) was moderately below average and 4 (36%) had severe cognitive and behavioral deficiencies. Brain MRI in 5 of 5 patients was notable for cerebellar atrophy without supratentorial involvement. Antineuronal activity was detected in sera of 0 of 10 children at follow-up. CONCLUSIONS: Certain patients with neuroblastoma associated OMA may achieve average-range neurobehavioral function in spite of residual neurologic abnormalities, with suggestion of continued improvement over time. Late cerebellar atrophy appears to be a common finding regardless of neurologic outcome, whereas antineuronal immune reactivity does not appear to be a long-term feature of OMA.

Antibodies, Neoplasm↗

Gene transfer of the Bcl-2 gene confers cytoprotection to isolated adult porcine pancreatic islets exposed to xenoreactive antibodies and complement.

BACKGROUND: Exposing adult porcine pancreatic islets (PI) to xenoreactive natural antibodies (XNA) induces brisk inflammatory injury that involves activation of the complement system. Gene transfer of Bcl-2 has been shown to protect PI from apoptosis and necrosis in several models. In this study, we investigated the effect of Bcl-2 gene transfer on protection of PI from primate XNA and complement-mediated injury. METHODS: The PI were isolated from adult female sows. Only islet preparations that exhibited >90% viability and purity were used. Fresh rhesus monkey serum served as the XNA source. Gene transfer of Bcl-2 was achieved with an adenoviral vector (AdBcl-2) at 500 particle forming units (pfu)/cell. The Bcl-2 expression was confirmed by Western blot technique. Untransfected and transfected PI were incubated in 50% fresh complete serum (CS) or heat-inactivated (HI) rhesus serum for 24 hours. The PI viability was analyzed with acridine orange and ethidium bromide staining. Antibody and complement-mediated cytotoxicity were tested by intracellular lactate dehydrogenase (LDH) release. The PI function was assessed in vitro by static incubation studies and in vivo after intraportal transplantation in diabetic severe combined immunodeficiency (SCID) mice. RESULTS: The AdBcl-2 gene transfer resulted in Bcl-2 gene expression in >90% of PI cells. Following exposure to XNA, <15% of the untransfected cells were viable. Similar results were obtained in PI transfected with a similar recombinant adenovirus encoding the reporter gene E coli beta-galactosidase (AdLacZ), an irrelevant gene. A significant increase in LDH release was observed in control PI after exposure to CS compared with PI that overexpressed Bcl-2 (82.89% +/- 7.78% vs 34.31% +/- 5.4%, P <.005). Higher insulin release was observed in vitro in PI transfected with Bcl-2 compared with untransfected PI or islets transfected with AdLacZ (stimulation index of 0.9 +/- 0.31, 0.9 +/- 0.3 vs 2.67 +/- 0.4, respectively). Only PI treated with AdBcl-2 were able to achieve euglycemia after exposure to XNA and complement after transplantation. CONCLUSIONS: Transfer of the antiapoptotic and antinecrotic Bcl-2 gene into PI can reduce primate XNA and complement-mediated lysis. Cytoprotection of PI with Bcl-2 has potential to improve survival of PI xenotransplants.

Adenoviridae↗

Preventable risk factors for coronary heart disease and stroke amongst ethnic groups in London.

OBJECTIVES: People of African Caribbean descent have higher mortality rates from stroke than other ethnic groups. However, little is known about the prevalence of stroke risk factors in UK ethnic minority groups. We investigated the prevalence of these risk factors amongst African Caribbeans, black Africans and whites. DESIGN: A random sample of patients aged 45-74 registered with 16 general practices in south London was surveyed in 1995. Main outcome measures were: prevalence of hypertension, mean serum cholesterol, serum fibrinogen and glycosylated haemoglobin AIC. Logistic and linear regressions were used to determine ethnic differences in these measures. RESULTS: Hypertension was more prevalent in black Caribbeans (79.4%) and black Africans (71.6%) than in whites (54.3%) (p < 0.0001). There were ethnic group differences in mean random total cholesterol (p < 0.0001), triglycerides (p < 0.0001), fibrinogen (p = 0.03), HDL (p = 0.02) and HbAIC (p < 0.0001). Whites had higher mean random total cholesterol, triglycerides and fibrinogen than black Caribbeans but lower HDL and HbA1C. Black Africans had similar rates to black Caribbeans for these risk factors apart from lower triglvceride levels. CONCLUSION: These differences in risk factors may partially explain the high stroke mortality rates in black Caribbeans and black Africans compared to whites. There was little difference in prevalence of these risk factors between black Caribbean and black African groups. Specific strategies targeted to each ethnic group need to be developed to reduce risk factors.

Africa↗

Cloning and biochemical characterization of FOX-5, an AmpC-type plasmid-encoded beta-lactamase from a New York City Klebsiella pneumoniae clinical isolate.

Klebsiella pneumoniae 5064, isolated in New York, carried plasmid-mediated resistance to multiple beta-lactams and was unresponsive to clavulanic acid. The beta-lactamase gene responsible for cephalosporin resistance encoded FOX-5, with 96 to 97% amino acid identities to other members of the FOX family of beta-lactamases. The bla(FOX-5) coding region was located next to a transposase gene from the Aeromonas salmonicida insertion element ISAS2.

Aged↗

Androgen suppression of GnRH-stimulated rat LHbeta gene transcription occurs through Sp1 sites in the distal GnRH-responsive promoter region.

Steroids may regulate LH subunit gene transcription by modulating hypothalamic GnRH pulse patterns or by acting at the pituitary gonadotrope to alter promoter activity. We tested direct pituitary effects of the androgen dihydrotestosterone (DHT) to modulate the rat LHbeta promoter in transfected LbetaT2 clonal gonadotrope cells and in pituitaries of transgenic mice expressing LHbeta-luciferase. The LHbeta promoter (-617 to +44 bp)-luciferase construct was stimulated in LbetaT2 cells 7- to 10-fold by GnRH. Androgen treatment had little effect on basal promoter activity but suppressed GnRH stimulation by approximately 75%. GnRH stimulation of LHbeta was also suppressed by DHT in isolated pituitary cells from male or female mice with functional nuclear ARs, but not in male littermates with mutant AR. GnRH stimulation of the LHbeta promoter requires interactions between a complex distal response element containing two specificity protein-1 (Sp1) binding sites and a CArG box, and a proximal element with two bipartite binding sites for steroidogenic factor-1 and early growth response protein-1 (Egr-1). DHT effectively suppressed promoter constructs with an intact distal response element. The distal response element does not bind AR, but AR reduces Sp1 binding to this region. Glutathione-S-transferase pull-down studies demonstrated direct interactions of AR with Sp1, which requires the DNA-binding domain of AR, and weaker interactions with Egr-1. We conclude that androgen suppression of the rat LHbeta promoter occurs primarily through direct interaction of AR with Sp1, with some possible role through binding to Egr-1. These interactions result in interference with GnRH-stimulated gene transcription by reducing cooperation between the distal and proximal GnRH response elements.

Animals↗

Effects of intravenous secretin on language and behavior of children with autism and gastrointestinal symptoms: a single-blinded, open-label pilot study.

BACKGROUND: Autism is a severe developmental disorder with poorly understood etiology. A recently published case series describes 3 autistic children with gastrointestinal symptoms who underwent endoscopy and intravenous administration of secretin and were subsequently noted by their parents to demonstrate improved language skills over a 5-week period. This report sparked tremendous public interest, and investigators at several sites moved quickly to design controlled trials to test the efficacy of secretin as a therapy for autistic children. However, this is the first effort specifically designed to replicate the initial reported findings in terms of patient age, presenting symptoms, and drug administration. OBJECTIVE: To rigorously apply the scientific method by assessing the reproducibility of the reported effects of intravenous secretin on the language of young children with autism and gastrointestinal symptoms. METHODS: We performed a single-blinded, prospective, open-label trial by conducting formal language testing and blinded behavioral rating both before and repeatedly after a standardized infusion of secretin. We selected autistic children who were similar in age and profile to those described in the published retrospective case review. Inclusion criteria for study participation included age (3-6 years), confirmed diagnosis of autism, and reported gastrointestinal symptoms (16 had chronic diarrhea, 2 had gastroesophageal reflux, and 2 had chronic constipation). Twenty children (18 male) were admitted to the Pediatric Clinical Research Center at the University of California, San Francisco after administration of the Preschool Language Scale-3 (PLS-3). A 3 CU/kg dose of secretin (Secretin-Ferring) was administered intravenously (upper endoscopy was not performed). Behavioral ratings were derived using the Autism Observation Scale applied to a 30-minute time sample of the child's behavior consisting of a videotape of the PLS-3 (structured setting) and a second free play session with a standard set of developmentally appropriate toys. Participants then returned for follow-up evaluations, with readministrations of the PLS-3 at 1, 2, 3, and 5 weeks' postinfusion, and videotaping of each session for later blinded review by 2 independent observers using the Autism Observation Scale, uninformed about week of posttreatment. We also surveyed parents of our study children about their impressions of the effects of secretin using a 5-point Likert scale for parents to rate changes seen in their child. RESULTS: With a total study completion rate across all participants of 96%, repeated measures analyses of variance revealed no significant increases in children's language skills from baseline across all 5 study time periods after a single infusion of secretin. Similarly, neither significant decreases in atypical behaviors nor increases in prosocial behaviors and developmentally appropriate play skills emerged. Furthermore, no relationship was found between parental reports of change and observable improvement in the sample. Despite the objective lack of drug effect, 70% of parents in our study reported moderate to high change in their child's language and behavior. Furthermore, 85% of parents reported that they felt that their child would obtain at least some additional benefits from another infusion of secretin. CONCLUSIONS: The results of our pilot study indicate that intravenous secretin had no effects in a 5-week period on the language and behavior of 20 children with autism and gastrointestinal symptoms. The open-label, prospective design of our study with blinded reviews of patients both before and after secretin administration follows the scientific method by seeking to reproduce an observed phenomenon using validating and reliable outcome measures. Pilot studies remain a mandatory step for the design of future randomized, clinical trials investigating potential treatments for children with autism.

Analysis of Variance↗

Successful reversal of streptozotocin-induced diabetes with stable allogeneic islet function in a preclinical model of type 1 diabetes.

The recent focus on islet transplantation as primary therapy for type 1 diabetes has heightened interest in the reversal of type 1 diabetes in preclinical models using minimal immunosuppression. Here, we demonstrated in a preclinical rhesus model a consistent reversal of all measured glycemic patterns of streptozotocin-induced type 1 diabetes. The model used single-donor islet transplantation with induction of operational tolerance. The term "operational tolerance" is used to indicate durable survival of single-donor major histocompatibility complex (MHC)-mismatched islet allografts without maintenance immunosuppressive therapy and without rejection or loss of functional islet mass or insulin secretory reserve. In this operational tolerance model, all immunosuppression was discontinued after day 14 posttransplant, and recipients recovered with excellent health. The operational tolerance induction protocol combined peritransplant anti-CD3 immunotoxin to deplete T-cells and 15-deoxyspergualin to arrest proinflammatory cytokine production and maturation of dendritic cells. T-cell deficiency was specific but temporary, in that T-cell-dependent responses in long-term survivors recovered to normal, and there was no evidence of increased susceptibility to infection. Anti-donor mixed lymphocyte reaction responses were positive in the long-term survivors, but all showed clear evidence of systemic T-helper 2 deviation, suggesting that an immunoregulatory rather than a deletional process underlies this operational tolerance model. This study provides the first evidence that operational tolerance can protect MHC nonhuman primate islets from rejection as well as loss of functional islet mass. Such an approach has potential to optimize individual recipient recovery from diabetes as well as permitting more widespread islet transplantation with the limited supply of donor islets.

Animals↗

Combined X-Ray and fully leaky guided mode studies of the smectic layer and optic tensor configuration in a ferroelectric liquid-crystal cell.

X-ray scattering together with optical characterization using fully leaky guided modes have been used for the first time to study the same ferroelectric liquid-crystal cell. This enables direct calculation of an accurate cone and chevron description of the liquid-crystal director profile since the layer structure and optic tensor configuration are both well known.

Journal Article↗