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Biomedical subjects

A Malhotra

Publications and source records attributed to A Malhotra.

At least 37 records · Page 2Linked to original sources
PubMed2004

Comparative evaluation of Tc-99m-heat-denatured RBC and Tc-99m-anti-D IgG opsonized RBC spleen planar and SPECT scintigraphy in the detection of accessory spleen in postsplenectomy patients with chronic idiopathic thrombocytopenic purpura.

OBJECTIVE: Radionuclide imaging specific for functioning splenic tissue is considered the method of choice to detect an accessory spleen in patients of chronic idiopathic thrombocytopenia purpura (ITP), who present with relapse after splenectomy. Radioimmunospleen scintigraphy with Tc-99m-labeled autologous RBC opsonized with anti-D IgG (RIS) is claimed to be more sensitive and specific than Tc-99m heat-denatured RBC spleen scintigraphy (HDRS) in the detection of an accessory spleen. We compared the efficacy of RIS with HDRBC for the detection of accessory spleens METHODS: A total of 45 patients (male:female = 17:28, age range: 6-58 years) who presented with relapse of ITP after splenectomy underwent scintigraphy with both methods. An average of 3 years had passed since surgery. All patients were imaged by a dual-head gamma camera with high-resolution collimators; planar static images and SPECT of abdomen were acquired. RESULTS: Accessory spleens were detected in 31% (14 of 45) of patients, 6 had 1 each and 8 had more than 1 (including 1 patient who had 13 accessory spleens). Both methods were concordant in all the patients. There was no difference in the scintigraphic picture (planar and SPECT) or in the size and number of accessory spleens detected. CONCLUSION: Tc-99m-labeled anti-D IgG opsonized autologous RBC spleen scintigraphy provides no additional diagnostic information over heat-denatured RBC spleen scintigraphy. Heat-denatured RBC scintigraphy thus remains the procedure of choice in the detection of accessory spleens.

Adolescent↗
PubMed2004

Role of Tc-glucoheptonic acid brain single photon emission computed tomography in differentiation of recurrent brain tumour and post-radiation gliosis.

Blood-brain barrier imaging of brain tumours is fast attracting interest now that it has been demonstrated that disruption of the blood-brain barrier is essential for uptake of all tumour-seeking agents. The aim of the present study was to differentiate recurrent tumour from post-radiation gliosis using (99m)technetium-glucoheptonate ((99m)Tc-GHA) as a tumour-seeking agent. Brain single photon emission computed tomography (SPECT) with (99m)Tc-GHA was performed in 73 patients with primary malignant brain tumours after radiotherapy, and the results were correlated with the clinical behaviour of the disease on follow up. The SPECT was suggestive of recurrent tumour in 55 patients. The clinical course was consistent with recurrence in 51 of the 55 patients. The clinical course was consistent with radiation necrosis in the remaining 21 patients, which included 17 patients with a negative SPECT and four patients with a positive SPECT study. Mean GHA index in recurrent tumour and post-radiation gliosis was 7.04 +/- 4.35 and 1.88 +/- 1.70, respectively (P = 0.0001). Mean GHA index in high-grade and low-grade glioma was 7.78 +/- 4.73 and 3.15 +/- 2.44, respectively (P = 0.001). (99m)Technetium-glucoheptonate brain SPECT is a sensitive and reliable diagnostic modality to differentiate recurrent tumour from post-radiation gliosis.

Adolescent↗
PubMed2004

Ecological diversification in a group of Indomalayan pitvipers (Trimeresurus): convergence in taxonomically important traits has implications for species identification.

We analyse molecular and phenotypic evolution in a group of taxonomically problematic Indomalayan pitvipers, the Trimeresurus sumatranus group. Mitochondrial DNA sequencing provides a well-resolved phylogeny, with each species representing a distinct lineage. Multivariate morphological analysis reveals a high level of phenotypic differentiation, which is congruent between the sexes but does not reflect phylogenetic history. An adaptive explanation for the observed pattern of differentiation is supported by independent contrasts analysis, which shows significant correlations between current ecology and the characters that most account for the variation between taxa, including those that are presently used to identify the species. Reduced precipitation and altitude, and increased temperature, are correlated with higher numbers of scales on the head, body and tail. It is hypothesized that scale number plays an important role in heat and water exchange by influencing the area of exposed of interstitial skin, and that colour pattern variation reflects selection pressures involving camouflage and thermoregulation. Ecological convergence in traits used for classification is found to have important implications for species identification where taxa are distributed over varying environments.

Animals↗
PubMed2004

Treatment considerations for vertebroplasty in men.

BACKGROUND AND PURPOSE: Vertebroplasty is now a widely accepted image-guided intervention in patients with compression fracture. The purpose of this report is to look specifically at the male population undergoing vertebroplasty and identfy the management considerations distinct to men. METHODS: The hospital medical records and radiographic studies of 24 men treated with vertebroplasty between February 1999 and November 2000 were retrospectively reviewed. RESULTS: Five patients presented with idiopathic or secondary osteoporosis. In two of these five men, malignancies were discovered by core biopsies taken at the time of vertebroplasty. Thirteen patients (54%) had secondary osteoporosis. Of this group, 10 patients (42%) were steroid dependent and three (13%) were hypogonadal. Five patients (21%) had traumatic events leading to fracture. One presented with known metastases. CONCLUSION: Primary osteoporosis in men is unusual. In male patients without a definable cause of osteoporosis, known metastatic disease, or a significant history of trauma, the routine performance of a vertebral biopsy through the vertebroplasty needle before the injection of bone cement is indicated to identify unexpected neoplasm.

Aged↗
PubMed2003

Metastases to the breast revisited: radiological-histopathological correlation.

Metastases to the breast from extramammary tumours are infrequent. The main challenge in diagnosis is differentiating them from primary breast cancer. Radiologically this can be difficult as there are no specific imaging characteristics for metastases to the breast. Cytopathological evaluation, as well as full radiological assessment, is vital to avoid unnecessary surgery. Sources of primary tumours include a wide variety of cancers. In this pictorial review we illustrate a number of the commonest sources of primary tumours including lymphoma, lung, ovarian and cervical carcinoma, intestinal carcinoid and rare cases of Ewing's sarcoma and malignant pigmented melanocytic schwannoma (low-grade malignant melanoma).

Adult↗
PubMed2003

Scintigraphic patterns of lymphocele in post-renal transplant.

Lymphocele is a common cause of fluid collection in post-renal transplant patients. Most of these patients are routinely followed up with 99mTc diethylenetriaminepentaacetate renal dynamic scintigraphy. The present study retrospectively reviews the range of findings with renal dynamic scintigraphy in documented lymphoceles. A lymphocele was diagnosed when there was a pelvic collection on ultrasonography with a similar biochemical composition to plasma. Four types of scintigraphy patterns were noted in lymphocele in a total of 13 patients. In nine patients there was an initial photopenic area, which progressively filled up with tracer activity equal to that of the background level in delayed images. In two other patients, the activity in the initial photopenic area exceeded the background activity in delayed images. A persistently photopenic area was seen in early and delayed images in the two remaining patients. In addition, a rim of increased tracer activity was noted surrounding the photopenic area in four patients in the early images. In conclusion, an initial photopenic area (with or without a surrounding rim of increased tracer activity), which fills up with tracer in delayed images seems to be the most common pattern seen in lymphoceles in scintigraphic studies of renal transplants. The presence of a rim sign may add confidence to the reporting of a collection as a lymphocele.

Humans↗
PubMed2002

Long-term follow-up of untreated patients with sleep apnoea syndrome.

Obstructive sleep apnoea (OSA) is a common disorder with numerous potential sequelae. Although the majority of these consequences can be reduced with appropriate treatment, only limited data exist regarding the natural progression ofthis disorder in untreated individuals. We hereby report a long-term follow-up of all untreated patients (n = 40) followed-up in the Technion Sleep Clinic, using both subjective and objective measurements. In addition, we report a long-term follow-up of 11 patients who attempted dietary weight loss. The average time interval between the first and second polysomnographies for the untreated group was 5.0 +/- 2.8 yrs, and 2.5 +/- 2.3 yrs for the weight reduction group. There was no significant change in Body Mass Index (BMI) or Respiratory Disturbance Index (RDI) between the two Polysomnographic (PSG) evaluations in the untreated patients. However, eight patients developed hypertension (n=5) or ischaemic heart disease (IHD) (n=3) between the two evaluations. RDI, age and BMI at the time ofthe initial evaluation were not predictive of changes in RDI, snoring intensity or minimal oxygen saturation. However, the patients who developed hypertension/IHD had significantly higher RDI than the patients who did not (46 +/- 27 vs. 23 +/- 17 h(-1), P < 0.005). In the weight-loss group, BMI decreased by a mean of 3.1 kg m(-2), and RDI decreased by 20events h(-1), P<0.05 for both. There was a significant correlation between the weight loss and improvement in RDI (R = 0.75, P = 0.005). We conclude that in untreated obstructive sleep apnoea patients RDI does not necessarily increase over time, but associated hypertension or ischaemic heart disease may develop. When weight loss is successfully achieved, sleep apnoea significantly improves with a high correlation between the extent of weight loss and the improvement in apnoea status.

Adult↗
PubMed2001

Genioglossal activation in patients with obstructive sleep apnea versus control subjects. Mechanisms of muscle control.

Pharyngeal dilator muscle activation (GGEMG) during wakefulness is greater in patients with obstructive sleep apnea (OSA) than in healthy control subjects, representing a neuromuscular compensatory mechanism for a more collapsible airway. As previous work from our laboratory has demonstrated a close relationship between GGEMG and epiglottic pressure, we examined the relationship between genioglossal activity and epiglottic pressure in patients with apnea and in control subjects across a wide range of epiglottic pressures during basal breathing, negative-pressure (iron-lung) ventilation, heliox breathing, and inspiratory resistive loading. GGEMG was greater in the patients with apnea under all conditions (p < 0.05 for all comparisons), including tonic, phasic, and peak phasic GGEMG. In addition, patients with apnea generated a greater peak epiglottic pressure on a breath-by-breath basis. Although the relationship between GGEMG and epiglottic negative pressure was tight across all conditions in both groups (all R values > = 0.69), there were no significant differences in the slope of this relationship between the two groups (all p values > 0.30) under any condition. Thus, the increased GGEMG seen in the patient with apnea during wakefulness appears to be a product of an increased tonic activation of the muscle, combined with increased negative-pressure generation during inspiration.

Airway Resistance↗
PubMed2001

Nuclear and mtDNA phylogenies of the Trimeresurus complex: implications for the gene versus species tree debate.

Phylogenies based on mitochondrial DNA (mtDNA) may represent gene trees that may not be congruent with the equivalent species tree. One solution to this problem is to include additional, independent loci from the nuclear genome. Sequence data from the seventh intron of the beta-fibrinogen gene were generated for 25 specimens of vipers, including 8 nominal species of the Trimeresurus complex of Asian pit vipers. Phylogenetic trees were generated using maximum-parsimony and maximum-likelihood methods. The taxonomic level at which the intron provided significant phylogenetic information was examined and the trees were compared to those produced from previously obtained mtDNA cytochrome b sequences. A variety of different approaches (separate analyses, conditional data combination, and consensus) were used in an attempt to provide a sound organismal phylogeny based on both nuclear and mtDNA data sets. We discuss the implications for the gene tree-species tree debate and its particular relevance to medically important organisms.

Animals↗
PubMed2001

Genioglossal inspiratory activation: central respiratory vs mechanoreceptive influences.

Upper airway dilator muscles are phasically activated during respiration. We assessed the interaction between central respiratory drive and local (mechanoreceptive) influences upon genioglossal (GG) activity throughout inspiration. GG(EMG) and airway mechanics were measured in 16 awake subjects during baseline spontaneous breathing, increased central respiratory drive (inspiratory resistive loading; IRL), and decreased respiratory drive (hypocapnic negative pressure ventilation), both prior to and following dense upper airway topical anesthesia. Negative epiglottic pressure (P(epi)) was significantly correlated with GG(EMG) across inspiration (i.e. within breaths). Both passive ventilation and IRL led to significant decreases in the sensitivity of the relationship between GG(EMG) and P(epi) (slope GG(EMG) vs P(epi)), but yielded no change in the relationship (correlation) between GG(EMG) and P(epi). During negative pressure ventilation, pharyngeal resistance increased modestly, but significantly. Anesthesia in all conditions led to decrements in phasic GG(EMG), increases in pharyngeal resistance, and decrease in the relationship between P(epi) and GG(EMG). We conclude that both central output to the GG and local reflex mediated activation are important in maintaining upper airway patency.

Adult↗
PubMed2001

Stress-induced hyperglycemia.

Stress hyperglycemia is common and likely to be associated with at least some of the same complications as hyperglycemia in true diabetes mellitus, such as poor wound healing and a higher infection rate. The predominant cause is the intense counterregulatory hormone and cytokine responses of critical illness, often compounded by excessive dextrose administration, usually as TPN. Although randomized data suggesting benefit of controlling hyperglycemia in hospitalized patients are paltry, prospective controlled trials are feasible and should be initiated. In the interim, the practice at the authors' institution is to use insulin to lower plasma glucose concentrations to a safe range of 150 mg/dL to 200 mg/dL in all patients.

Glucose↗
PubMed2001

Adolescent girls' life aspirations and reproductive health in Nepal.

The study described in this paper takes a participatory and positive approach to improving adolescent reproductive health in a rural and urban community in Nepal. It shows that adolescent girls in these communities have dreams and aspirations for a better future and that adults acknowledge and support these ideals. However, social norms and institutions are restrictive, especially for girls, who are often unable to realise their hopes for continuing education, finding better-paid work or delaying marriage and childbearing, and this directly impacts reproductive outcomes. Insight into the broader context of adolescent girls' lives provides a valuable framework for designing positive programmatic actions which take as their entry point the disjuncture between girls' aspirations and realities. Interventions begun in these communities include youth clubs for safe social interaction and literacy classes; training of peer educators to teach life-skills, including for married adolescents; forums for parents, teachers and health service providers to discuss their own concerns and those of adolescents; and work with the community to design programmes that will contribute to greater financial independence and employment opportunities for adolescents.

Adolescent↗
PubMed2001

Molecular biology of protein kinase C signaling in cardiac myocytes.

The PKC family of serine/threonine kinases have been implicated in a diverse array of cellular responses. Adult cardiac myocytes express multiple PKC isozymes, which participate in the response of muscle cells to extracellular stimuli, modulate contractile properties, and promote cell growth and survival. Recently, the classification of this ubiquitous family of signaling molecules has been expanded from three to four subfamilies. This review will focus on the application of pharmacologic and molecular approaches to explore the biology of cardiac PKC isozymes. The availability of transgenic mice and peptide PKC modulators have been instrumental in identifying target substrates for activated cardiac PKC isozymes, as well as the identification of specific isozymes linked to distinct growth characteristics and cell phenotype. The rapid growth of knowledge in the area of PKC signaling and PKC substrate interactions, may result in the development of therapeutic modalities with the potential to arrest or reverse the progression of cardiovascular diseases.

Animals↗
PubMed2001

Multiple causation of phylogeographical pattern as revealed by nested clade analysis of the bamboo viper (Trimeresurus stejnegeri) within Taiwan.

In order to assess the utility of nested clade analysis, both standard phylogenetic algorithms and nested clade analysis were performed on a geographically widespread survey of mitochondrial DNA haplotypes of the bamboo viper, Trimeresurus stejnegeri, within Taiwan. Gross tree topologies were congruent for all analyses and indicated the presence of two geographically overlapping clades within Taiwan. The smaller lineage was restricted to the north and east coasts, whereas the larger lineage occupied all but the northern range of the species within Taiwan including the Pacific offshore populations of Green and Orchid Islands. The phylogeographical pattern supports the existence of at least one colonization event from the continent since the initial isolation of Taiwan from the mainland in the Pliocene. However, determining the exact number of colonization events was not possible due to the simultaneous vicariant forces of hypothesized continental landbridge connections and the occurrence of dramatic in situ orogenesis throughout the Pleistocene. Nested clade analysis provided multiple temporal and spatial population historical inferences that are not possible with standard analyses and therefore should become widely applied to future phylogeographical studies.

Animals↗