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Biomedical subjects

A Srivastava

Publications and source records attributed to A Srivastava.

At least 127 records · Page 7Linked to original sources
PubMed2001

Inter-pregnancy folate and iron status of women in an inner-city population.

The purpose of the present study was to evaluate whether micronutrient supplementation improved the nutritional status of women with poor diets during the inter-pregnancy interval. Fifty-five women who had given birth to a low birth weight baby (<2.5 kg), and who planned to have a further pregnancy, were recruited to a prospective randomised study in East London, UK. Of the fifty-five mothers recruited, forty-four (78 %) met fewer than four of sixteen dietary reference values according to the information provided in a 7 d diet diary, and were categorised as having an 'inadequate' diet. Half of the mothers in the 'inadequate'-diet group were randomly assigned to receive a micronutrient and a single cell oil supplement containing docosahexaenoic acid. All participants received dietary advice based on analysis of their diet diaries, and general lifestyle advice on preparing for pregnancy. Mothers had a blood sample taken at 3 and 9 months post-partum to measure their folate, Fe stores and fatty acid status. Mean serum and erythrocyte folate levels increased significantly between 3 and 9 months post-partum in both the adequate-diet group and the supplemented group. At 9 months post-partum, over half of the unsupplemented, inadequate-diet group remained severely deficient in folate (serum folate <230 nmol/l) and had low serum ferritin levels (<15 microg/l). The high prevalence of inadequate diets in this inner-city population and the low motivation of women to participate in a nutrition programme suggests that consideration should be given to the provision of free folate and Fe supplements to all women in this and similar populations, or at least to women who have delivered a low birth weight baby, who plan further pregnancies.

Adolescent↗
PubMed2001

Endopyelotomy in poorly functioning kidney: is it worthwhile?

BACKGROUND: Endopyelotomy is a minimally invasive surgical alternative for primary ureteropelvic junction (UPJ) obstruction. However, its success in poorly functioning kidneys is controversial. PATIENTS AND METHODS: In this retrospective study, 34 endopyelotomies performed on poorly functioning kidneys between January 1993 and December 1997 were reviewed. Of these, 13 patients had a glomerular filtration rate (GFR) <15 mL/min (Group I) and 21 had a GFR of 15 to 25 mL/min (Group II). All the patients insisted on endopyelotomy to avoid open surgery. Antegrade endopyelotomy was performed by the twin guidewire rail technique with a cold knife. An indwelling stent was kept for 2 to 6 weeks. Patients were followed up with assessment of symptoms and diuretic renograms at 3, 6, and 12 months postoperatively. RESULTS: Endopyelotomy was considered successful in 8 of 13 patients (62%) in Group I. Success was achieved in 19 of 21 patients (90%) in Group II. CONCLUSION: Endopyelotomy can be performed for improvement of symptoms. Stabilization or improvement in GFR is less pronounced in poorly functioning kidneys with primary UPJ obstruction.

Adolescent↗
PubMed2001

Use of porcine acellular dermal matrix as a dermal substitute in rats.

OBJECTIVE: To examine porcine acellular dermal matrix (ADM) as a xenogenic dermal substitute in a rat model. SUMMARY BACKGROUND DATA: Acellular dermal matrix has been used in the treatment of full-thickness skin injuries as an allogenic dermal substitute providing a stable wound base in human and animal studies. METHODS: Xenogenic and allogenic ADMs were produced by treating porcine or rat skin with Dispase and Triton X-100. Full-thickness skin defects (225 mm2) were created on the dorsum of rats (n = 29), porcine or rat ADMs were implanted in them, and these were overlain with ultrathin split-thickness skin grafts (STSGs). In two adjacent wounds, 0.005- or 0.017-inch-thick autografts were implanted. In other experiments, the antimicrobial agent used during ADM processing (azide or a mixture of antibiotics) and the orientation of the implanted ADM (papillary or reticular side of ADM facing the STSG) were studied. Grafts were evaluated grossly and histologically for 30 days after surgery. RESULTS: Significant wound contraction was seen at 14, 20, and 30 days after surgery in wounds receiving xenogenic ADM, allogenic ADM, and thin STSGs. Contraction of wounds containing xenogenic ADM was significantly greater than that of wounds containing allogenic ADM at 30 days after surgery. Graft take was poor in wounds containing xenogenic ADM and moderately good in those containing allogenic ADM. Wound healing was not significantly affected by the antimicrobial agent used during ADM preparation or by the ADM orientation. CONCLUSION: Dispase-Triton-treated allogenic ADM was useful as a dermal substitute in full-thickness skin defects, but healing with xenogenic ADM was poor.

Animals↗
PubMed2001

Adeno-associated virus type 2-mediated gene transfer: role of cellular FKBP52 protein in transgene expression.

Although adeno-associated virus type 2 (AAV) has gained attention as a potentially useful vector for human gene therapy, the transduction efficiencies of AAV vectors vary greatly in different cells and tissues in vitro and in vivo. We have documented that a cellular tyrosine phosphoprotein, designated the single-stranded D-sequence-binding protein (ssD-BP), plays a crucial role in AAV-mediated transgene expression (K. Y. Qing, X.-S. Wang, D. M. Kube, S. Ponnazhagan, A. Bajpai, and A. Srivastava, Proc. Natl. Acad. Sci. USA 94:10879-10884, 1997). We have documented a strong correlation between the phosphorylation state of ssD-BP and AAV transduction efficiency in vitro as well as in vivo (K. Y. Qing, B. Khuntrirat, C. Mah, D. M. Kube, X.-S. Wang, S. Ponnazhagan, S. Z. Zhou, V. J. Dwarki, M. C. Yoder, and A. Srivastava, J. Virol. 72:1593-1599, 1998). We have also established that the ssD-BP is phosphorylated by epidermal growth factor receptor protein tyrosine kinase and that the tyrosine-phosphorylated form, but not the dephosphorylated form, of ssD-BP prevents AAV second-strand DNA synthesis and, consequently, results in a significant inhibition of AAV-mediated transgene expression (C. Mah, K. Y. Qing, B. Khuntrirat, S. Ponnazhagan, X.-S. Wang, D. M. Kube, M. C. Yoder, and A. Srivastava, J. Virol. 72:9835-9841, 1998). Here, we report that a partial amino acid sequence of ssD-BP purified from HeLa cells is identical to a portion of a cellular protein that binds the immunosuppressant drug FK506, termed the FK506-binding protein 52 (FKBP52). FKBP52 was purified by using a prokaryotic expression plasmid containing the human cDNA. The purified protein could be phosphorylated at both tyrosine and serine or threonine residues, and only the phosphorylated forms of FKBP52 were shown to interact with the AAV single-stranded D-sequence probe. Furthermore, in in vitro DNA replication assays, tyrosine-phosphorylated FKBP52 inhibited AAV second-strand DNA synthesis by greater than 90%. Serine- or threonine-phosphorylated FKBP52 caused approximately 40% inhibition, whereas dephosphorylated FKBP52 had no effect on AAV second-strand DNA synthesis. Deliberate overexpression of FKBP52 effectively reduced the extent of tyrosine phosphorylation of the protein, resulting in a significant increase in AAV-mediated transgene expression in human and murine cell lines. These studies corroborate the idea that the phosphorylation status of the cellular FKBP52 protein correlates strongly with AAV transduction efficiency, which may have important implications for the optimal use of AAV vectors in human gene therapy.

3T3 Cells↗
PubMed2001

Adeno-associated virus type 2-mediated gene transfer: altered endocytic processing enhances transduction efficiency in murine fibroblasts.

Adeno-associated virus type 2 (AAV) is a single-stranded-DNA-containing, nonpathogenic human parvovirus that is currently in use as a vector for human gene therapy. However, the transduction efficiency of AAV vectors in different cell and tissue types varies widely. In addition to the lack of expression of the viral receptor and coreceptors and the rate-limiting viral second-strand DNA synthesis, which have been identified as obstacles to AAV-mediated transduction, we have recently demonstrated that impaired intracellular trafficking of AAV inhibits high-efficiency transduction of the murine fibroblast cell line, NIH 3T3 (J. Hansen, K. Qing, H. J. Kwon, C. Mah, and A. Srivastava, J. Virol. 74:992-996, 2000). In this report, we document that escape of AAV from the endocytic pathway in NIH 3T3 cells is not limited but processing within endosomes is impaired compared with that observed in the highly permissive human cell line 293. While virions were found in both early and late endosomes or lysosomes of infected 293 cells, they were localized predominantly to the early endosomes in NIH 3T3 cells. Moreover, treatment of cells with bafilomycin A1 (Baf), an inhibitor of the vacuolar H(+)-ATPase and therefore of endosomal-lysosomal acidification, decreased the transduction of 293 cells with a concomitant decrease in nuclear trafficking of AAV but had no effect on NIH 3T3 cells. However, after exposure of NIH 3T3 cells to hydroxyurea (HU), a compound known to increase AAV-mediated transduction in general, virions were detected in late endosomes and lysosomes, and these cells became sensitive to Baf-mediated inhibition of transduction. Thus, HU treatment overcomes defective endocytic processing of AAV in murine fibroblasts. These studies provide insights into the underlying mechanisms of intracellular trafficking of AAV in different cell types, which has implications in the optimal use of AAV as vectors in human gene therapy.

3T3 Cells↗
PubMed2001

Recombinant human parvovirus B19 vectors: erythrocyte P antigen is necessary but not sufficient for successful transduction of human hematopoietic cells.

The blood group P antigen, known to be abundantly expressed on erythroid cells, has been reported to be the cellular receptor for parvovirus B19. We have described the development of recombinant parvovirus B19 vectors with which high-efficiency, erythroid lineage-restricted transduction can be achieved (S. Ponnazhagan, K. A. Weigel, S. P. Raikwar, P. Mukherjee, M. C. Yoder, and A. Srivastava, J. Virol. 72:5224-5230, 1998). However, since a low-level transduction of nonerythroid cells could also be detected and since P antigen is expressed in nonerythroid cells, we reevaluated the role of P antigen in the viral binding and entry into cells. Cell surface expression analyses revealed that approximately 75% of primary human bone marrow mononuclear erythroid cells and approximately 31% of cells in the nonerythroid population were positive for P antigen. Two human erythroleukemia cell lines, HEL and K562, and a human promyelocytic leukemia cell line, HL-60, were also examined for P antigen expression and binding and entry of the vector. HEL and K562 cells showed intermediate levels, whereas HL-60 cells demonstrated high levels of expression of P antigen. However, the efficiency of vector binding to these cells did not correlate with P antigen expression. Moreover, despite P antigen positivity and efficient viral binding, HEL, K562, and HL-60 cells could not be transduced with the vector. Low levels of P antigen expression could also be detected in two primary cell types, human umbilical vein endothelial cells (HUVEC) and normal human lung fibroblasts (NHLF). In addition, vector binding occurred in both cell types and was inhibited by globoside, indicating the involvement of P antigen in virus binding to these cells. These primary cells could be efficiently transduced with the recombinant vector. These data suggest that (i) P antigen is expressed on a variety of cell types and is involved in binding of parvovirus B19 to human cells, (ii) the level of P antigen expression does not correlate with the efficiency of viral binding, (iii) P antigen is necessary but not sufficient for parvovirus B19 entry into cells, and (iv) parvovirus B19 vectors can be used to transduce HUVEC and NHLF. These studies further suggest the existence of a putative cellular coreceptor for efficient entry of parvovirus B19 into human cells.

Antigens, Surface↗
PubMed2001

Localized prostate cancer: effect of hormone deprivation therapy measured by using combined three-dimensional 1H MR spectroscopy and MR imaging: clinicopathologic case-controlled study.

PURPOSE: To determine the accuracy of combined magnetic resonance (MR) imaging and three-dimensional (3D) proton MR spectroscopic imaging in localizing prostate cancer to a sextant of the gland in patients receiving hormone deprivation therapy. MATERIALS AND METHODS: Combined MR imaging/3D MR spectroscopic imaging examinations were performed in 16 hormone-treated patients and 48 nontreated matched control patients before radical prostatectomy and step-section histopathologic analysis. At MR imaging, cancer presence within the peripheral zone was assessed on a per sextant basis by two readers. At 3D MR spectroscopic imaging, cancer was identified by using (choline plus creatine)-to-citrate ratios at cutoff values of 2 and 3 SDs above mean normal peripheral zone values. Data were compared by using receiver operating characteristic analysis. RESULTS: There was no significant difference in the ability of combined MR imaging/3D MR spectroscopic imaging to localize prostate cancer in treated versus control patients. For MR imaging alone, the sensitivity and specificity were 91% and 48% (reader 1) and 75% and 60% (reader 2) in treated patients versus 79% and 60% (reader 1) and 84% and 43% (reader 2) in control patients. For 3D MR spectroscopic imaging alone (>3 SDs cutoff), higher specificity (treated, 80%; controls, 73%) but lower sensitivity (treated, 56%; controls, 53%) was attained. In treated patients, high sensitivity or specificity (up to 92%) was achieved when either or both modalities indicated cancer. CONCLUSION: When performed within 4 months after initiating hormone deprivation therapy, combined MR imaging/3D MR spectroscopic imaging had the same accuracy in localizing prostate cancer as in nontreated patients.

Antineoplastic Agents, Hormonal↗
PubMed2001

Juvenile rheumatoid arthritis with amyloid goiter: report of a case with review of the literature.

Clinically significant enlargement of the thyroid owing to amyloid deposition is a rare occurrence. A 23-yr-old female, a case of juvenile rheumatoid arthritis, developed rapidly increasing thyromegaly during the course of her illness with complaints of dyspnea and dysphagia. Thyroid function tests were within normal limits. Fine-needle aspiration cytology proved inconclusive. Total thyroidectomy was done for symptomatic relief with a preoperative clinical impression of malignancy. Histopathologic findings were consistent with amyloid goiter. The findings of this case are presented, to emphasize the difficulties in making a definite preoperative diagnosis, along with a brief review of the literature.

Adult↗
PubMed2001

Glutathione S-transferase activity influences busulfan pharmacokinetics in patients with beta thalassemia major undergoing bone marrow transplantation.

Busulfan, at a dose of 16 mg/kg, is widely used in combination with cyclophosphamide as a conditioning regimen for patients undergoing bone marrow transplantation. Wide interindividual variation in busulfan kinetics and rapid clearance of the drug have been reported, especially in children. Some of the factors contributing to interpatient variability have been identified. They include circadian rhythms, age, disease, drug interaction, changes in hepatic function, and busulfan bioavailability. In this study, we demonstrate that hepatic glutathione S-transferase (GST) activity correlates negatively with busulfan maximum and minimum concentrations (Pearson's correlation r = -0.74 and -0.77, respectively) and positively with busulfan clearance (Pearson's correlation r = 0.728) in children with thalassemia major in the age range of 2 to 15 years. We also found that plasma alpha GST levels were 5 to 10 times higher in patients with thalassemia than in normal controls and age-matched leukemic patients, either reflecting extensive liver damage, elevated expression of the enzyme, or both in thalassemic patients. Plasma alpha GST concentrations showed a similar correlation with busulfan kinetic parameters to that observed for hepatic GST. The status of hepatic GST activity accounts, at least in part, for the observed interindividual variation in busulfan kinetics, while the observed association with plasma alpha GST is difficult to explain at present.

Adolescent↗
PubMed2001

Money and subjective well-being: it's not the money, it's the motives.

Past researchers have argued that the relative importance a person attaches to money is negatively related to subjective well-being (SWB). However, the past research suffers from the theoretical problem of not including the diferent motives for making money. With a sample of 240 business students, the authors developed a set of scales to measure motives for making money. They used a sample of 492 business students to confirm the factor structure of these motives. With another sample of 266 business students, the authors found that the negative relationship between money importance and SWB was due to the two variables being the result of a common cause; namely, the motives of social comparison. seeking power, showing off, and overcoming self-doubt. This finding was replicated with a sample of 145 entrepreneurs.

Adult↗
PubMed2001

Risk of breast and ovarian cancer in women with strong family histories.

Assessing the risk of breast and ovarian cancer starts with obtaining a complete and accurate family history. This can reveal evidence of inherited cancer risk. The highest risk of cancer is associated with germ-line abnormalities in several genes, including BRCA1, BRCA2, and TP53. Moderate-risk genes associated with syndromes that are inherited in an autosomal dominant pattern (such as Cowden's disease, hereditary non-polyposis colorectal cancer, Muir-Torre syndrome, and Peutz-Jeghers syndrome) exhibit lower penetrance and thus less risk of breast and/or ovarian cancer. Low-risk genes likely require significant environmental exposure, and although they are associated with the lowest risk of cancer, they account for more cancer than high- and moderate-risk genes. Lifetime risks for breast or ovarian cancer can be estimated. The Gail and Claus models, the more widely utilized models for calculation of lifetime breast cancer risk, are discussed. Models are also available for determining the likelihood of finding a BRCA1/2 mutation (the BRCAPRO and Myriad models). Appropriate candidates for testing include affected individuals who are most likely to have a hereditary form of cancer. Testing should proceed only after a thorough discussion of the risks, benefits, and limitations of testing. Risk-reducing options are available to women with a strong family history of breast and ovarian cancer. These options include high-risk screening, chemoprevention, and prophylactic surgery.

Age Distribution↗
PubMed2001

Parvovirus vectors for human gene therapy.

It has become increasingly clear that parvovirus-based vectors are a potentially safe and useful alternative to the more commonly used retroviral and adenoviral vectors. Parvovirus vectors have been successfully used in phase I clinical trials for gene therapy of cystic fibrosis and hemophilia B, and several salient features of these vectors provide further support to the suggestion that their use in potential gene therapy of a wide variety of human diseases is imminent and perhaps well justified.

Dependovirus↗
PubMed2001

Cost-effectiveness analysis of laparoscopic versus minilaparotomy cholecystectomy for gallstone disease. A randomized trial.

OBJECTIVE: To evaluate the total cost of minilaparotomy cholecystectomy (MC) and laparoscopic cholecystectomy (LC) and perform a cost-effectiveness (CE) analysis. METHODS: One hundred adult subjects with painful gallstone disease were randomized: 59 cases for LC and 41 cases for MC. Patients with gallstones shown on ultrasound with normal common bile duct and no history of icterus were included after an informed consent. Cases with acute cholecystitis and raised alkaline phosphatase were excluded. LC was performed using CO2 insufflation and a Storz 2D video camera. MC was done by transverse rectus cutting incision. Outcome was coded as success or failure. Success was defined as operation without injury to bile duct, viscera or vessels, minimal pain and discomfort at 4 weeks, no wound infection up to 4 weeks, and resumption of work within 2 weeks of operation. The total cost of each case included cost of investigations, cost of disposable articles for operation, cost of drugs, cost of hospital stay, and cost of operation including anesthesia. LC and MC were done with reusable instruments. A "societal viewpoint" has been taken in the cost calculations. RESULTS: There were 50/59 successful outcomes in LC and 15/40 outcomes in MC group. Total cost for LC was 386,769 rupees (Rs) and for MC was Rs 205,041. CE in LC was Rs 7,735 and in MC was Rs 13,669. Incremental CE ratio comparing LC with MC was 3,028.33. CONCLUSION: LC is a more cost-effective method for treatment of gallstone disease.

Adult↗
PubMed2001

Coeliac disease in Indian children: assessment of clinical, nutritional and pathologic characteristics.

Coeliac disease is an important cause of chronic diarrhoea, failure to thrive, and anaemia in children. Little information on the disease is available in India. This study was undertaken to determine the prevalence, clinical, anthropometric and histological profiles of coeliac disease in patients attending a tertiary referral centre in India. Coeliac disease was diagnosed in 42 (16.6%) of 246 children with chronic diarrhoea, failure to thrive, and anaemia. The mean ages at onset of symptoms and at diagnosis were 2.4 (range 0.5-10) years and 8.3 (range 3-14) years respectively, and a mean period of delay in diagnosis was 5.9 (range 1-13.5) years. Of the 42 cases, history of failure to thrive was observed in 38 (90%), chronic diarrhoea in 37 (88%), and anaemia in 6 cases. Short stature, under-nutrition, anaemia, oedema of feet, rickets, clubbing of fingers, features of vitamin A deficiency, and B-vitamin deficiency were found in 42, 26, 38, 9, 8, 6, 3, and 2 cases respectively. Onset of symptoms, such as, chronic diarrhoea and failure to thrive, was earlier in children with subtotal villous atrophy than in those with partial villous atrophy (mean +/- SD; 2.00 +/- 1.46 years vs 3.30 +/- 2.72 years; p < 0.05). Results of the study suggest that coeliac disease is not uncommon in Indian children. Coeliac disease should be considered in the differential diagnosis, particularly in children without any symptoms of diarrhoea.

Adolescent↗
PubMed2001

A pilot study on the role of cytomegalovirus & human herpesvirus-6 infections in Indian bone marrow transplant recipients.

BACKGROUND & OBJECTIVES: Studies from Western transplant centers have shown the importance of cytomegalovirus (CMV) in infections among immunosuppressed post-transplant patients (both solid and bone marrow transplant recipients). Human herpesvirus-6 (HHV-6) infection is also important. Since such data are lacking from India, we carried out a pilot study to investigate the role of these two viruses in infections among Indian allogeneic bone marrow transplant (BMT) recipients. METHODS: A total of 21 BMT patients who developed acute graft versus host disease (GVHD), two patients who developed chronic GVHD, and eight recipients who did not develop GVHD but had skin rash/elevated liver enzymes, persistent cytopaenia or interstitial pneumonitis with a high clinical suspicion of possible CMV association were studied for markers of CMV and HHV-6 infections. RESULTS: CMV DNAemia was documented in 9 (42.8%) and CMV IgM in 4(19%) of the 21 patients with acute GVHD. HHV-6 DNAemia was not seen in any patient with acute GVHD but 2 (9.5%) had HHV-6 IgM. Of the 2 patients with chronic GVHD, 1 was positive for CMV DNA and IgM, and both were negative for HHV-6 markers. The lower incidence of CMV DNAemia in our recipients may be attributable to the presence of neutralizing antibody (anti gB/AD-1) among the 17 CMV and HHV-6 DNAemia negative recipients, 4(23.5%) had neutralizing antibodies (S/N ratio > or = 5). Of the 13 CMV DNAemia positive recipients, only one (7.7%) was positive for neutralizing antibodies. Among the 5 neutralizing antibody (S/N ratio > or = 5) positive recipients, 4 (80%) were negative for CMV DNAemia. The one nPCR positive was revealed only at high DNA (> 0.1 microgram) input indicating low CMV signal strength. INTERPRETATION & CONCLUSION: The present study shows the use of DNAemia in detecting CMV infections among BMT recipients. All recipients had high avidity CMV IgG (AI > 50%) confirming CMV reactivation or reinfection in these patients. There was evidence from this study suggesting that neutralizing antibodies may play a role in controlling CMV reactivation. We found no significant HHV-6 association with GVHD in Indian allogeneic BMT recipients.

Adolescent↗