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Biomedical subjects

J Shah

Publications and source records attributed to J Shah.

At least 91 records · Page 5Linked to original sources
PubMed2000

Recurrent familial neonatal deaths: hereditary surfactant protein B deficiency.

Hereditary surfactant protein B (SP-B) deficiency is an uncommon autosomal recessive lung disorder that causes hypoxemic respiratory failure in mature, morphologically normal infants. Recognition and diagnosis of this condition is of paramount importance, as it has significant implications for future pregnancies with a recurrence risk of 25%. In a family with three neonatal deaths over 20 years, SP-B deficiency was diagnosed following the death of the fourth affected infant. Previous deaths were mistakenly attributed to hyaline membrane disease (HMD), congenital Mycoplasma hominis infection, and pulmonary hypertension, however, following the diagnosis in the proposita, SP-B deficiency was also confirmed in her deceased siblings by immunohistochemical staining of autopsy specimens. This case highlights the presentation, postnatal course, diagnosis, and therapeutic options of SP-B deficiency in addition to the mode of inheritance and the possibility of antenatal diagnosis. Genetic consultation is imperative in the investigations of recurrent neonatal deaths, especially in cases of remote events. The recent enormous advances in human genetics have shown that many conditions previously ascribed to environmental agents have a genetic basis.

Fatal Outcome↗
PubMed2000

Intramedullary tuberculomas. MR findings in seven patients.

PURPOSE: To describe the MR findings in intramedullary tuberculomas and to discuss the usefulness of MR in the management of this pathology. MATERIAL AND METHODS: A retrospective study of 7 patients from 21 to 60 years of age with clinical and radiological evidence of intramedullary tuberculomas was undertaken. Both T1- and T2-weighted images (WI) were obtained along with postcontrast T1WI. Signal intensities (SIs) of the granulomas were compared with SIs of the normal spinal cord. RESULTS: Six patients showed focus of tuberculosis elsewhere in the body. Six out of 7 showed fusiform swelling of the cord. Ill-defined iso-intensity (in 4 patients) to hyperintensity (in 3 patients) was seen at the site of granuloma on T1WI. On T2WI, 2 patients revealed a hypointense area (with disc enhancement). An iso-hypointense rim was seen surrounding a hyperintense centre in 5 patients (with rim enhancement). Adjacent oedema was seen in all patients. In 2 patients meningeal enhancement was also seen. In 2 patients the histopathology following surgical biopsy confirmed the diagnosis. In the remaining 5 patients, another known focus of tuberculosis elsewhere in the body and a marked response to antitubercular treatment was considered confirmatory for tuberculomas. CONCLUSION: Hypo- or iso-intensity on T2WI within the spinal cord with surrounding hyperintense oedema is suggestive of intramedullary tuberculomas. Central hyperintensities are also detected at times due to a variable amount of caseous necrosis with liquefaction. On T1WI, fusiform swelling of the cord is seen along with iso- to hyperintense foci, surrounded by hypointense oedema of the cord. Such findings should prompt a contrast-enhanced study, which may show single or conglomerate disc- or ring-enhancing lesions. MR thus plays an important role not only in detection and diagnosis, but also in deciding the treatment options and in the follow-up of those patients.

Adult↗
PubMed2000

Motor block during patient-controlled epidural analgesia with ropivacaine or ropivacaine/fentanyl after intrathecal bupivacaine for caesarean section.

We compared patient-controlled epidural analgesia (PCEA) with ropivacaine alone or combined with fentanyl in terms of analgesic efficacy, motor weakness and side-effects in patients who had received spinal anaesthesia for elective Caesarean section. ASA I patients received combined spinal-epidural anaesthesia and were randomly assigned, in a double-blind study, into two groups after operation: group R (n = 23) received PCEA ropivacaine 0.1%, bolus 5 mg, lock-out 15 min, 3 mg h-1 background infusion, and group RF (n = 24) received PCEA 0.1% ropivacaine/fentanyl 2 micrograms ml-1 at identical settings. Pain and satisfaction on a 100 mm visual analogue scale (VAS) and side-effects were noted. Incidence of motor weakness (Bromage grade 1 or higher) was 48% (11/23) at 8 h in group R compared with 13% (3/24) in group RF (P = 0.025). Pain scores on movement were lower in group RF at 8 and 12 h and at rest at 6 and 8 h (P < 0.05 for each comparison). Analgesic consumption was less in RF (P = 0.041), but there was no difference in time to first request for supplementary analgesia. Patient satisfaction with postoperative analgesia (mean (SD)) was higher in RF (79 (23) vs 57 (29) mm, P = 0.045). Caution should be exercised using ropivacaine PCEA after spinal bupivacaine for Caesarean section, because its reputed motor-sparing property may be unreliable.

Adult↗
PubMed2000

Warm air sensation for assessment of block after spinal anaesthesia.

We have evaluated a new method of assessing dermatomal sensory levels after regional anaesthesia based on warm sensation. Sensory levels were assessed in 30 patients after spinal anaesthesia using a respiratory gas humidifier, adapted to deliver a constant flow of warm air at 40 +/- 0.2 degrees C. This was compared with the cold sensation from ethyl chloride spray. The frequency distribution of the dermatomal differences showed 96.6% of the comparisons were between +1 and -1 dermatomes. The median difference in dermatomal levels between the two methods of assessment was 0 (interquartile range 0-1) (P = 0.65). We conclude that the warm air method compares favourably with ethyl chloride spray and both can be used interchangeably.

Adolescent↗
PubMed2000

NPR1 differentially interacts with members of the TGA/OBF family of transcription factors that bind an element of the PR-1 gene required for induction by salicylic acid.

NPR1 is a critical component of the salicylic acid (SA)-mediated signal transduction pathway leading to the induction of defense genes, such as the pathogenesis-related (PR)-1 gene, and enhanced disease resistance. Using a yeast two-hybrid screen, we identified several NPR1-interacting proteins (NIPs). Two of these NIPs are members of the TGA/OBF family of basic leucine zipper (bZIP) transcription factors; this family has been implicated in the activation of SA-responsive genes, including PR-1. Six TGA family members were tested and shown to differentially interact with NPR1: TGA2 and TGA3 showed strong affinity for NPR1; TGA5 and TGA6 exhibited weaker affinity; and TGA1 and TGA4 displayed little or no detectable interaction with NPR1, respectively. Interestingly, the amino-termini of these factors were found to decrease their stability in yeast and differentially affect their apparent affinity toward NPR1. The interacting regions on NPR1 and the TGA factors were also defined. Each of four point mutations in NPR1 that disrupt SA signaling in Arabidopsis completely blocked interaction of NPR1 with TGA2 and TGA3. TGA2 and TGA3 were also found to bind the SA-responsive element of the Arabidopsis PR-1 promoter. These results directly link NPR1 to SA-induced PR-1 expression through members of the TGA family of transcription factors.

Amino Acid Sequence↗
PubMed2000

Relationship between EEG and positron emission tomography abnormalities in clinical epilepsy.

Positron emission tomography (PET) is a relatively noninvasive neuroimaging method by means of which a large variety of human brain functions can be assessed. Localized neurochemical abnormalities detected by PET were found in patients with partial epilepsy and suggested the use of this modality for localizing epileptogenic regions of the brain. The clinical usefulness of PET is determined by its sensitivity and specificity for identifying epileptogenic areas as defined by ictal surface and intracranial EEG recordings. The findings obtained from comparative EEG and glucose PET data are reviewed with special emphasis on patients undergoing presurgical evaluation because of medically intractable temporal and extratemporal lobe epilepsy. The utility of glucose PET studies for identifying regions of seizure onset is presented, and the limited specificity of glucose metabolic abnormalities for the detection of various EEG patterns in clinical epilepsy is discussed. The authors review the available intracranial EEG and PET comparisons using [11C]flumazenil (FMZ) PET, a tracer for the assessment of tau-amino-butyric acid/benzodiazepine receptor function. They also summarize their experience with [11C]flumazenil PET in identifying cortical regions that show various ictal and interictal cortical EEG abnormalities in patients with extratemporal seizure origin. Finally, the authors demonstrate that further development of new PET tracers, such as alpha-[11C]methyl-L-tryptophan, is feasible and clinically useful and may increase the number of patients in whom PET studies can replace invasive EEG monitoring.

Biomarkers↗
PubMed2000

Resistance to turnip crinkle virus in Arabidopsis is regulated by two host genes and is salicylic acid dependent but NPR1, ethylene, and jasmonate independent.

Inoculation of turnip crinkle virus (TCV) on the resistant Arabidopsis ecotype Dijon (Di-17) results in the development of a hypersensitive response (HR) on the inoculated leaves. To assess the role of the recently cloned HRT gene in conferring resistance, we monitored both HR and resistance (lack of viral spread to systemic tissues) in the progeny of a cross between resistant Di-17 and susceptible Columbia plants. As expected, HR development segregated as a dominant trait that corresponded with the presence of HRT. However, all of the F(1) plants and three-fourths of HR(+) F(2) plants were susceptible to the virus. These results suggest the presence of a second gene, termed RRT, that regulates resistance to TCV. The allele present in Di-17 appears to be recessive to the allele or alleles present in TCV-susceptible ecotypes. We also demonstrate that HR formation and TCV resistance are dependent on salicylic acid but not on ethylene or jasmonic acid. Furthermore, these phenomena are unaffected by mutations in NPR1. Thus, TCV resistance requires a yet undefined salicylic acid-dependent, NPR1-independent signaling pathway.

Arabidopsis↗
PubMed2000

Carcinoma following augmentation ileocystoplasty.

Carcinoma of the bladder following augmentation cystoplasty is rare. Only 15 cases have been reported worldwide. We report a further 2 cases, 1 of which, a squamous cell carcinoma, has not previously been described in this context.

Aged↗
PubMed2000

Use of 'locked-in' antibiotic to treat an unusual gram-negative hemodialysis catheter infection.

A 37-year-old woman on maintenance hemodialysis for 3 years had multiple vascular access failures due to antiphospholipid syndrome. She was dialyzed via a tunneled left subclavian catheter, but after 1 year developed chills and fever during each dialysis session. Blood cultures grew out Xanthomonas maltophilia sensitive to ceftazidime and ciprofloxacin. Intravenous administration of both antibiotics failed to eradicate infection. We added 'locked-in' ceftazidime, instilling it daily into the catheter along with heparinized saline for 3 weeks. Within 24 h the patient was dialyzed uneventfully, and all subsequent blood cultures have been negative. This case shows the successful use of a 'locked-in' antibiotic to treat an unusual gram-negative catheter infection. Two prior series have reported similar good results in infections with more common organisms. Such treatment may permit continued use of tunneled hemodialysis catheters for longer periods.

Adult↗
PubMed2000

Is epileptogenic cortex truly hypometabolic on interictal positron emission tomography?

Positron emission tomography (PET) of glucose metabolism is often applied for the localization of epileptogenic brain regions, but hypometabolic areas are often larger than or can miss epileptogenic cortex in nonlesional neocortical epilepsy. The present study is a three-dimensional brain surface analysis designed to demonstrate the functional relation between glucose PET abnormalities and epileptogenic cortical regions. Twelve young patients (mean age, 10.8 years) with intractable epilepsy of neocortical origin underwent chronic intracranial electroencephalographic monitoring. The exact location of the subdural electrodes was determined on high-resolution three-dimensional reconstructed magnetic resonance imaging scan volumes. The electrodes were classified according to their locations over cortical areas, which were defined as hypometabolic, normometabolic, or at the border between hypometabolic and normal cortex (metabolic "border zones") based on interictal glucose PET. Electrodes with seizure onset were located over metabolic border zones significantly more frequently than over hypometabolic or normometabolic regions. Seizure spread electrodes also more frequently overlay metabolic border zones than hypometabolic regions. These findings suggest that cortical areas with hypometabolism should be interpreted as regions mostly not involved in seizure activity, although epileptic activity commonly occurs in the surrounding cortex. This feature of hypometabolic cortex is remarkably similar to that of structural brain lesions surrounded by epileptogenic cortex. Cortical areas bordering hypometabolic regions can be highly epileptogenic and should be carefully assessed in presurgical evaluations.

Brain Diseases, Metabolic↗
PubMed2000

Cytochalasin E, an epoxide containing Aspergillus-derived fungal metabolite, inhibits angiogenesis and tumor growth.

Several previously identified inhibitors of angiogenesis have been epoxide-containing fungus-derived metabolites. We therefore hypothesized that novel epoxide-containing low molecular weight compounds structurally resembling known antiangiogenic agents may also exhibit antiangiogenic activity. Cytochalasin E was found to be a potent and selective inhibitor of bovine capillary endothelial (BCE) cell proliferation. Cytochalasin E differed from other cytochalasins by the presence of an epoxide. The epoxide was required for activity, because acid-catalyzed hydrolysis of the epoxide abrogated the specificity and potency of cytochalasin E. Phalloidin staining indicated that disruption of actin stress fibers by cytochalasin E occurred only at relatively high concentrations. Lower concentrations of cytochalasin E preferentially inhibited BCE cell proliferation without disrupting actin stress fibers. In vivo, cytochalasin E inhibited angiogenesis induced by basic fibroblast growth factor by 40% to 50% in the mouse cornea assay and inhibited the growth of Lewis lung tumors by approximately 72%. Cytochalasin E is a potent antiangiogenic agent that may hold promise for the treatment of cancer and other types of pathologic angiogenesis.

3T3 Cells↗
PubMed1999

Glucose and [11C]flumazenil positron emission tomography abnormalities of thalamic nuclei in temporal lobe epilepsy.

OBJECTIVES: To analyze interictal patterns of thalamic nuclei glucose metabolism and benzodiazepine receptor binding in patients with medically intractable temporal lobe epilepsy (TLE) using high-resolution 2-deoxy-2-[18F]fluoro-D-glucose (FDG) and [11C]flumazenil (FMZ) PET. BACKGROUND: Structural and glucose metabolic abnormalities of the thalamus are considered important in the pathophysiology of TLE. The differential involvement of various thalamic nuclei in humans is not known. METHODS: Twelve patients with TLE underwent volumetric MRI, FDG and FMZ PET, and prolonged video-EEG monitoring. Normalized values and asymmetries of glucose metabolism and FMZ binding were obtained in three thalamic regions (dorsomedial nucleus [DMN], pulvinar, and lateral thalamus [LAT]) defined on MRI and copied to coregistered, partial-volume-corrected FDG and FMZ PET images. Hippocampal and amygdaloid FMZ binding asymmetries and thalamic volumes also were measured. RESULTS: The DMN showed significantly lower glucose metabolism and FMZ binding on the side of the epileptic focus. The LAT showed bilateral hypermetabolism and increased FMZ binding. There was a significant correlation between the FMZ binding asymmetries of the DMN and amygdala. The PET abnormalities were associated with a significant volume loss of the thalamus ipsilateral to the seizure focus. CONCLUSIONS: Decreased [11C]flumazenil (FMZ) binding and glucose metabolism of the dorsomedial nucleus (DMN) are common and have strong lateralization value for the seizure focus in human temporal lobe epilepsy. Decreased benzodiazepine receptor binding can be due to neuronal loss, as suggested by volume loss, but also may indicate impaired gamma-aminobutyric acid (GABA)ergic transmission in the DMN, which has strong reciprocal connections with other parts of the limbic system. Increased glucose metabolism and FMZ binding in the lateral thalamus could represent an upregulation of GABA-mediated inhibitory circuits.

Adolescent↗
PubMed1999

Identifying objects in conventional and contorted poses: contributions of hemisphere-specific mechanisms.

Three experiments were designed to test the hypothesis that different mechanisms are used to encode objects seen in unfamiliar contortions than are used to encode objects seen in conventional poses. When a familiar non-rigid form (e.g. an animal) is seen in a contorted pose, we hypothesize that object identification may be achieved by (1) encoding the object's parts separately, (2) encoding the spatial relations among the parts, and (3) matching these encoding to a stored structural description. However, once this form has become familiar, its global shape can be directly matched to information stored in memory. Based on the ideal that 'categorical' spatial relations are encoded better by the left cerebral hemisphere and are used in structural descriptions, we predicted a left-hemisphere advantage when one first encodes contorted poses; in contrast, based on the idea that overall shapes are encoded better by the right hemisphere, we predicted a right-hemisphere advantage for encoding the same shapes after they are familiar. Three experiments confirmed these predictions, which supports the hypotheses that different visual mechanisms operate in the recognition of familiar and unfamiliar views of known non-rigid objects. Moreover, correlational analyses between visual-field differences in several perceptual tasks (matching whole pictures to names, body parts to the whole body, and judging categorical spatial relations) revealed that the degree and lateralization of categorical spatial encoding predicts the left hemisphere's initial advantage in the identification of contorted shapes.

Brain↗
PubMed1999

Pulmonary metastasectomy for head and neck cancers.

BACKGROUND: Distant metastases from carcinomas that arise from the head and neck region are infrequent. The most common site is the lung. To evaluate the results of resection of pulmonary metastases for head and neck cancers, we reviewed our own cases of these metastases. METHODS: Between November 1966 and March 1995, 83 patients with pulmonary metastases from head and neck cancers underwent 94 thoracic operations. All patients had obtained or had obtainable locoregional control of their primary head and neck cancers. Kaplan-Meier and Cox regression models were used to analyze the prognostic factors for survival after metastasectomy. RESULTS: Median age was 53 years (range, 17-77). Fifty-nine were male and 24 were female. Forty-one patients had squamous cell cancers, and 36 had glandular tumors that consisted mostly of thyroid and adenoid cystic carcinomas. The median disease-free interval from the time of treatment of the head and neck primary cancers to the development of pulmonary metastases was 27 months. Sixty-eight (82%) patients had complete resection. Overall operative mortality rate was 2%. Overall actuarial survival rate after metastasectomy was 50% at 5 years. Patients with glandular tumors had a 5-year survival rate of 64% compared with 34% for patients with squamous cell cancers. When the patients with glandular tumors were analyzed according to their histology, patients with adenoid cystic carcinomas had an 84% 5-year survival, but none remained disease-free. Patients with thyroid cancers fared similarly whether they were treated medically or surgically. On multivariate analysis, the adverse prognostic factors for patients with squamous cell cancers were incomplete resection, age greater than 50 years, and disease-free interval less than or equal to 2 years. CONCLUSIONS: Approximately 30% of patients with pulmonary metastases from squamous cell cancers of the head and neck who underwent complete resection of all their metastases can expect to achieve long-term survival. The role of pulmonary resection for patients with glandular tumors is unclear.

Adenocarcinoma↗
PubMed1999

Effectiveness of antenatal steroids in obstetric subgroups.

OBJECTIVE: To determine the effectiveness of antenatal steroids in the reduction of neonatal morbidity and mortality in obstetric subgroups of preterm labor with intact membranes, preterm premature rupture of membranes (PROM), and pregnancy-associated hypertension. The secondary objective was to determine the effect of antenatal steroids in appropriate for gestational age (AGA) and growth-restricted neonates. METHODS: We studied the neonatal outcomes for all women who delivered infants weighing 1750 g or less at birth between January 1990 and July 1997 at our institution. The study population was divided primarily into three clinical groups: preterm labor with intact membranes, PROM, and pregnancy-associated hypertension. Secondarily, the total population was divided based on birth weight and gestational age into AGA and growth-restricted neonates. Within each obstetric subgroup, neonates exposed to antenatal steroids were compared with unexposed neonates for respiratory distress syndrome (RDS), intraventricular hemorrhage and periventricular leukomalacia, the incidence of major brain lesions, necrotizing enterocolitis, proved neonatal sepsis, patent ductus arteriosus, and neonatal death. The subgroups were also compared for gestational age at delivery, birth weight, birth weight percentile, Apgar scores, postnatal surfactant exposure, and clinical and histologic chorioamnionitis. Descriptive statistics, Student t test, chi2, Fisher exact test, and logistic regression were used for analysis. RESULTS: A total of 1148 neonates weighing 1750 g or less were delivered during the study period. There were 447 and 410 neonates delivered after preterm labor with intact membranes and PROM, respectively, and 245 neonates born to mothers with pregnancy-associated hypertension. Nine hundred twenty-eight neonates were AGA and the remaining 220 neonates were growth restricted. Antenatal steroids significantly decreased the incidence of RDS, the incidence and severity of intraventricular hemorrhage and periventricular leukomalacia, necrotizing enterocolitis, and neonatal mortality in preterm labor with intact membranes. In the presence of PROM, it significantly decreased the incidence and severity of intraventricular hemorrhage and periventricular leukomalacia and decreased neonatal mortality, with no apparent effect on the incidence of RDS. Antenatal steroids did not show any beneficial effect in pregnancy-associated hypertension and fetal growth restriction (FGR). Additionally, a significant increase was observed in the incidence of proved neonatal sepsis when antenatal steroids were used in pregnancy-associated hypertension. CONCLUSION: The effectiveness of antenatal steroids varies with the obstetric population studied. Antenatal steroids significantly decreased the incidence of major neonatal morbidity and mortality in the AGA preterm neonate delivered after preterm labor with intact membranes. Antenatal steroids did not show any benefit in cases of pregnancy associated with maternal hypertension or FGR. Its effect in the presence of PROM is limited to a significant reduction in the incidence and severity of intraventricular hemorrhage and periventricular leukomalacia and in neonatal death.

Apgar Score↗
PubMed1999

Worldwide variations in the prevalence of symptoms of atopic eczema in the International Study of Asthma and Allergies in Childhood.

BACKGROUND: Little is known about the prevalence of atopic eczema outside Northern Europe. OBJECTIVES: We sought to describe the magnitude and variation in the prevalence of atopic eczema symptoms throughout the world. METHODS: A cross-sectional questionnaire survey was conducted on random samples of schoolchildren aged 6 to 7 years and 13 to 14 years from centers in 56 countries throughout the world. Those children with a positive response to being questioned about the presence of an itchy relapsing skin rash in the last 12 months that had affected their skin creases were considered to have atopic eczema. Children whose atopic eczema symptoms resulted in sleep disturbance for 1 or more nights per week were considered to have severe atopic eczema. RESULTS: Complete data was available for 256,410 children aged 6 to 7 years in 90 centers and 458,623 children aged 13 to 14 years in 153 centers. The prevalence range for symptoms of atopic eczema was from less than 2% in Iran to over 16% in Japan and Sweden in the 6 to 7 year age range and less than 1% in Albania to over 17% in Nigeria for the 13 to 14 year age range. Higher prevalences of atopic eczema symptoms were reported in Australasia and Northern Europe, and lower prevalences were reported in Eastern and Central Europe and Asia. Similar patterns were seen for symptoms of severe atopic eczema. CONCLUSIONS: Atopic eczema is a common health problem for children and adolescents throughout the world. Symptoms of atopic eczema exhibit wide variations in prevalence both within and between countries inhabited by similar ethnic groups, suggesting that environmental factors may be critical in determining disease expression. Studies that include objective skin examinations are required to confirm these findings.

Adolescent↗