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Biomedical subjects

R Gupta

Publications and source records attributed to R Gupta.

At least 127 records · Page 7Linked to original sources
PubMed2003

Laparoscopic partial nephrectomy for renal tumor: single center experience comparing clamping and no clamping techniques of the renal vasculature.

PURPOSE: We performed a nonrandomized retrospective comparison of 2 techniques for laparoscopic partial nephrectomy, that is without and with clamping the renal vessels. MATERIALS AND METHODS: Between December 1997 and February 2002, 28 consecutive patients underwent transperitoneal laparoscopic partial nephrectomy for renal tumor. In group 1 (12 patients) partial nephrectomy was performed with ultrasonic shears and bipolar cautery without clamping the renal vessels, while in group 2 (16 patients) the renal pedicle was clamped before tumor excision. In group 2 patients intracorporeal kidney cooling was achieved by a ureteral catheter connected to 4C solution. Intracorporeal freehand suturing techniques were used to close the collecting system when opened and approximate the renal parenchyma. RESULTS: All procedures were successfully completed laparoscopically. Mean renal ischemia time +/- SD was 27.3 +/- 7 minutes (range 15 to 47) in group 2 patients. Mean laparoscopic operating time was 179.1 +/- 86 minutes (range 90 to 390) in group 1 compared with 121.5 +/- 37 minutes (range 60 to 210) in group 2 (p = 0.004). Mean intraoperative blood loss was significantly higher in group 1 than in group 2 (708.3 +/- 569 versus 270.3 +/- 281 ml., p = 0.014). Three patients in group 1 and 2 in group 2 required blood transfusions. Immediately postoperatively mean creatinine was 1.26 +/- 0.36 and 1.45 +/- 0.61 mg./dl. in groups 1 and 2, respectively (p = 0.075). Surgical margins were negative in all specimens. Pathological examination revealed renal cell cancer in 18 cases (stages pT1 in 17 and pT3a in 1), oncocytoma in 4, angiomyolipoma in 5 and renal adenoma in 1. CONCLUSIONS: Laparoscopic partial nephrectomy represents a feasible option for patients with small renal masses. Clamping the renal vessels during tumor resection and suturing the kidney mimics the open technique and seems to be associated with less blood loss and shorter laparoscopic operative time.

Aged↗
PubMed2003

Laparoscopic [correction of laproscopic] management of rectal injury during laparoscopic [correction of laproscopic] radical prostatectomy.

PURPOSE: Rectal injury is a potential complication of radical prostatectomy. Because laparoscopic radical prostatectomy is still a challenging procedure, we review the incidence and management of rectal injury in 1,000 cases of consecutive laparoscopic radical prostatectomy performed at our institution. MATERIALS AND METHODS: Of the first 1,000 laparoscopic transperitoneal radical prostatectomies performed between January 1998 and April 2002, 13 (1.3%) were complicated by rectal injury. Mean patient age was 66.5 years (range 58 to 76) and mean prostate specific antigen was 12.9 ng./ml. (range 2.9 to 26). Clinical stage was T1c, T2a and T2b in 5, 7 and 1 patient, respectively. Mean preoperative Gleason score was 5.8 (range 3 to 8). Once recognized the rectal defect was closed laparoscopically in 2 layers and tested for the absence of leakage. Broad-spectrum intravenous antibiotics were given for 7 days. Oral liquids were started the day after surgery with a low residue diet, and a regular diet was started on postoperative day 5. Healing of the vesicourethral anastomosis was confirmed by voiding cystourethrogram on postoperative day 5. RESULTS: All patients underwent a non-nerve sparing procedure except 1 in whom unilateral neurovascular bundle preservation was done. Of 13 injuries 11 were diagnosed and repaired intraoperatively, and 2 were diagnosed postoperatively. Of the 11 cases of intraoperative diagnosis and repair 9 healed primarily without colostomy and peritonitis was diagnosed in the remaining 2 on days 3 and 4, respectively. Of the latter 2 patients 1 required repair of a small rectal defect without colostomy while the other required colostomy. Colostomy was performed in the 2 patients with delayed diagnosis on days 3 and 4 but even then a rectourethral fistula developed in 1, necessitating secondary repair. Average urethral catheterization time was 8.6 days for the 9 patients with an uneventful immediate postoperative course and mean hospital stay was 6.8 days. For the remaining 4 patients urethral catheterization duration was 12, 13, 15 and 120 days, and hospital stay was 7, 16, 21 and 27 days, respectively. There was no perioperative mortality. CONCLUSIONS: Rectal injury during laparoscopic radical prostatectomy requires meticulous intraoperative repair in 2 layers, which allows primary healing without diversion colostomy. For injury prevention scrupulous attention is required during non-nerve sparing radical prostatectomy, particularly at the posterior surface of the prostatic apex.

Aged↗
PubMed2003

5alpha-reductase type 1 immunostaining is enhanced in some prostate cancers compared with benign prostatic hyperplasia epithelium.

PURPOSE: In the prostate testosterone is converted to the more potent androgen dihydrotestosterone by the enzymes 5alpha-reductase (5alphaR) types 1 (5alphaR1) and 2 (5alphaR2). Since 5alphaR2 is the dominant prostatic enzyme, the 5alphaR2 selective inhibitor finasteride has been widely used to treat benign prostatic hyperplasia (BPH). However, inhibition of both 5alphaR enzymes provides a greater decrease in serum dihydrotestosterone. We developed a specific antibody to 5alphaR1 and assessed expression in BPH and prostate cancer (pCa) tissue. The presence of this isoenzyme in localized prostate cancer would provide a rationale for assessing the efficacy of dual inhibition for prostate cancer prevention. MATERIALS AND METHODS: A polyclonal antibody to 5alphaR1 was developed and validated using 5alphaR1 and 5alphaR2 transfected COS-1 cells. A total of 26 BPH and 53 pCa specimens were assessed for 5alphaR1 protein expression using immunocytochemical methods. Also, 29 BPH and 37 pCa specimens were assayed for 5alphaR1 and 5alphaR2 enzyme activity. RESULTS: Specificity of the 5alphaR1 antibody was confirmed using transfected COS-1 cells. Cells transfected with 5alphaR1 showed specific staining in immunocytochemistry experiments and on Western blotting of cell lysates the expected 24 kDa band was observed. High intensity immunoreactivity for 5alphaR1 was observed in the tumor epithelium of 28% of pCa specimens. No high intensity epithelial staining was observed in BPH specimens. In 19% of pCa and 7% of BPH specimens 5alphaR1 enzyme activity was detected. CONCLUSIONS: The presence of increased 5alphaR1 in some prostatic malignancies suggests that it is worthwhile to investigate the use of a dual 5alphaR inhibitor to prevent or treat early stage prostate cancer.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed2003

Hepatic dysfunction in patients with extrahepatic portal venous obstruction.

BACKGROUND: Extrahepatic portal venous obstruction (EHPVO) developing due to thrombotic occlusion of the portal vein in children is generally considered a benign disease. Whether hepatic dysfunction develops in these patients in the absence of a gastrointestinal bleed has not been well studied. MATERIALS AND METHODS: Forty-three patients with EHPVO who had not bled in the last 3 months were studied. Patients were divided into those with (group I) or without ascites (group II). Matched cirrhotic patients with ascites (group III) served as controls. Clinical, biochemical, ultrasonographic, and histopathological evaluation was carried out. Portal biliopathy was assessed in five patients in group I and in 12 patients in group II by cholangiography. RESULTS: Of 43 EHPVO patients, ascites was seen in nine (21%) patients (group I). Thirty-four patients had no ascites (group II). Serum ALT (54 +/- 24 vs. 34 +/- 10 IU/l, P < 0.01), albumin (3.2 +/- 0.3 vs. 3.7 +/- 0.4 g/dl, P < 0.01), and prothrombin time difference (9.0 +/- 4.5 vs. 2.4 +/- 1.9 s, P < 0.05) were deranged in patients in group I compared with group II. Patients in group I were 4 years older, and the duration of portal hypertension was longer than in group II (11.5 vs. 5.6 year, P < 0.05). Portal biliopathy changes were significantly more severe in group I than in group II patients. Ascites was high gradient in all the patients in group I and the serum-ascitic albumin gradient was comparable between groups I and III. None of the EHPVO patients, but four cirrhotic patients, developed spontaneous bacterial peritonitis during a follow-up of 11 +/- 4 months. CONCLUSIONS: Hepatic dysfunction in the form of ascites and deranged liver functions is not uncommon in patients with EHPVO, more so in patients with prolonged portal hypertension. Based on our data it would be worthwhile to study whether prolonged portal vein thrombosis in EHPVO patients could lead to progressive liver disease.

Adolescent↗
PubMed2003

Isolated gastric varices: prevalence, clinical relevance and natural history.

BACKGROUND: Isolated ectopic gastric varices (IGV2) are present either in the body or antrum of the stomach or upper duodenum. The prevalence, natural history and clinical significance of these varices has not been adequately described. MATERIALS AND METHODS: Consecutive patients with portal hypertension, prospectively studied and diagnosed to have IGV2, were assessed for their time of appearance - primary (at first presentation) or secondary (after obliteration of oesophageal varices), association with other varices, portal hypertensive gastropathy and any overt bleeding. RESULTS: Fifty-three of the 1128 (4.7%) patients had IGV2. The IGV2 were commonly seen in the antrum (53%), duodenum (32%), or at both sites (11%) and rarely in body and fundus (4%). IGV2 were predominantly (84.9%) secondary in origin, developing after oesophageal variceal obliteration. The median time for emergence of secondary IGV2 was 8.2 months for patients with cirrhosis, 12.8 months for non-cirrhotic portal fibrosis and 10.8 months for extra-hepatic portal vein obstruction. Eight (15%) patients had primary IGV2, 6 of them had underlying portal vein obstruction. Portal gastropathy (p < 0.05) and UGI bleeding were more common in the secondary than in primary IGV2. Bleeding due to IGV2 was seen only in 3 (5.7%) patients during a mean follow-up of 36.3 +/- 12.1 months, and could be successfully managed with endoscopic ligation or obliteration. CONCLUSIONS: Isolated ectopic gastric varices are not uncommon and generally develop following obliteration of main variceal columns. They rarely bleed and often can be managed with endoscopic interventions.

Adult↗
PubMed2003

Avascular necrosis of the femoral head in adult Kuwaiti sickle cell disease patients.

While sickle cell disease (SCD) is generally mild in most Kuwaitis, because of their elevated fetal Hb levels, avascular necrosis of the femoral head (AVNFH) appears to be a common complication. It was recently documented in 26.7% of Kuwaiti children with SCD. There have, however, been no previous studies of adult patients. This is a 1-year study of consecutive, steady-state SCD patients seen in the hematology clinic of Mubarak Al-Kabeer Hospital. The patients' charts were reviewed for frequency of hospitalizations, any documented complications and steady-state complete blood count (CBC). MRI was performed using T1- and T2-weighted FATSAT sequences in coronal and axial planes with 4-mm-thick slices on a 1.5-tesla GE super-conducting magnet. Thirty-five patients were studied, consisting of 25 SS and 10 Sbeta(0)Thal patients aged between 17 and 44, with a mean age of 26.7 +/- 9.3 years. Seventeen (48.6%) had varying degrees of AVNFH; among the 70 hips examined, 29 (41.1%) were affected. Of the 17 patients affected, 11 (64.7%) were SS, while 6 (35.3%) were Sbeta(0)Thal. There were 14 (82.4%) males and 3 (17.6%) females (chi(2) = 8.6, p < 0.01). The mean age of those affected, 27.5 +/- 10.7 years, was not significantly higher than that of the unaffected (26.3 +/- 8.0 years). Eleven (64.7%) of those affected had a history of frequent vaso-occlusive crisis. No significant differences could be demonstrated in the mean CBC and Hb F values of the two groups; coexistent alpha-thal trait was not a factor in the SS group. Male gender was the only significant predisposing factor identified. While more patients with frequent vaso-occlusive crises were affected, the difference was not significant. AVNFH is, indeed, quite common among Kuwaiti SCD patients and there is a need for early institution of preventive and therapeutic protocols.

Adolescent↗
PubMed2003

Raman spectroscopy and structure of crystalline gallium phosphide nanowires.

Gallium phosphide nanowires with a most probable diameter of approximately 20.0 nm and more than 10 microns in length have been synthesized by pulsed laser vaporization of a heated GaP/5% Au target. The morphology and microstructure of GaP nanowires have been investigated by scanning electron microscopy and transmission electron microscopy. Twins have been observed along the crystalline nanowires, which have a growth direction of [111]. Raman scattering shows a 4 cm-1 downshift of the longitudinal optical phonon peak in the nanowire with respect to the bulk; the transverse optical phonon frequency and line width are, however, the same as in the bulk. The quantum confinement model first proposed by Richter et al. cannot explain the observed behavior of the Raman modes.

Crystallography↗
PubMed2003

Serial epidemiological surveys in an urban Indian population demonstrate increasing coronary risk factors among the lower socioeconomic strata.

OBJECTIVE: To determine trends of coronary risk factors in an Indian urban population and their association with educational level as marker of socioeconomic status. METHODS: Two successive coronary risk factor surveys were performed in randomly selected individuals. In the first study (in 1995) 2212 subjects (1415 men, 797 women) and in the second (in 2002) 1123 subjects (550 men, 573 women) were studied. Details of smoking, physical activity, hypertension, diabetes, coronary heart disease, body-mass index, waist-hip ratio, blood pressure and electrocardiography were evaluated. Fasting blood was examined for lipid levels in 297 (199 men, 98 women) in the first and in 1082 (532 men, 550 women) in the second study. Educational status was classified into Group 0: no formal education, Group I: 1-10 years, Group II: 11-15 years, and Group III: > 16 years. Current definitions were used for risk factors in both the studies. RESULTS: Prevalence of coronary risk factors, adjusted for age and educational status, in the first and second study in men was smoking/tobacco in 38.7 vs. 40.5%, leisure time physical inactivity in 70.8 vs. 66.1%, hypertension (> or = 140 and/or 90 mm Hg) in 29.5 vs. 33.7%, diabetes history in 1.1 vs. 7.8%, obesity (body-mass index > or = 25 Kg/m2) in 20.7 vs. 33.0%, and truncal obesity (waist:hip > 0.9) in 54.7 vs. 54.4%. In women, tobacco use was in 18.7 vs. 20.5%, leisure time physical inactivity in 72.4 vs. 75.3%, hypertension in 36.9 vs. 33.7%, diabetes history in 1.0 vs. 7.3%, obesity in 19.9 vs. 39.4%, and truncal obesity (waist:hip > 0.8) in 70.1 vs. 69.2%. In men, high total cholesterol > or = 200 mg/dl was in 24.6 vs. 37.4%, high LDL cholesterol > or = 130 mg/dl in 22.1 vs. 37.0%, high triglycerides > or = 150 mg/dl in 26.6 vs. 30.6% and low HDL cholesterol < 40 mg/dl in 43.2 vs. 54.9%; while in women these were in 22.5 vs. 43.1%, 28.6 vs. 45.1%, 28.6 vs. 28.7% and 45.9 vs. 54.2% respectively. In the second study there was a significant increase in diabetes, obesity, hypertension (men), total- and LDL cholesterol and triglycerides and decrease in HDL cholesterol (p < 0.05). In the first study with increasing educational status a significant increase of obesity, total cholesterol, LDL cholesterol and triglycerides and decrease in smoking was observed. In the second study increasing education was associated with decrease in smoking, leisure-time physical inactivity, total and LDL cholesterol, and triglycerides and increase in obesity, truncal obesity and hypertension (Least-squares regression p < 0.05). Increase in smoking, diabetes and dyslipidaemias was greater in the less educated groups. CONCLUSIONS: Significant increase in coronary risk factors--obesity, diabetes, total-, LDL-, and low HDL cholesterol, and triglycerides is seen in this urban Indian population over a seven year period. Smoking, diabetes and dyslipidaemias increased more in low educational status groups.

Adult↗
PubMed2002

An overview on fermentation, downstream processing and properties of microbial alkaline proteases.

Microbial alkaline proteases dominate the worldwide enzyme market, accounting for a two-thirds share of the detergent industry. Although protease production is an inherent property of all organisms, only those microbes that produce a substantial amount of extracellular protease have been exploited commercially. Of these, strains of Bacillus sp. dominate the industrial sector. To develop an efficient enzyme-based process for the industry, prior knowledge of various fermentation parameters, purification strategies and properties of the biocatalyst is of utmost importance. Besides these, the method of measurement of proteolytic potential, the selection of the substrate and the assay protocol depends upon the ultimate industrial application. A large array of assay protocols are available in the literature; however, with the predominance of molecular approaches for the generation of better biocatalysts, the search for newer substrates and assay protocols that can be conducted at micro/nano-scale are becoming important. Fermentation of proteases is regulated by varying the C/N ratio and can be scaled-up using fed-batch, continuous or chemostat approaches by prolonging the stationary phase of the culture. The conventional purification strategy employed, involving e.g., concentration, chromatographic steps, or aqueous two-phase systems, depends on the properties of the protease in question. Alkaline proteases useful for detergent applications are mostly active in the pH range 8-12 and at temperatures between 50 and 70 degrees C, with a few exceptions of extreme pH optima up to pH 13 and activity at temperatures up to 80-90 degrees C. Alkaline proteases mostly have their isoelectric points near to their pH optimum in the range of 8-11. Several industrially important proteases have been subjected to crystallization to extensively study their molecular homology and three-dimensional structures.

Bacteria↗
PubMed2002

Prediction of human protein function from post-translational modifications and localization features.

We have developed an entirely sequence-based method that identifies and integrates relevant features that can be used to assign proteins of unknown function to functional classes, and enzyme categories for enzymes. We show that strategies for the elucidation of protein function may benefit from a number of functional attributes that are more directly related to the linear sequence of amino acids, and hence easier to predict, than protein structure. These attributes include features associated with post-translational modifications and protein sorting, but also much simpler aspects such as the length, isoelectric point and composition of the polypeptide chain.

Computational Biology↗
PubMed2002

Bacterial alkaline proteases: molecular approaches and industrial applications.

Proteolytic enzymes are ubiquitous in occurrence, being found in all living organisms, and are essential for cell growth and differentiation. The extracellular proteases are of commercial value and find multiple applications in various industrial sectors. Although there are many microbial sources available for producing proteases, only a few are recognized as commercial producers. A good number of bacterial alkaline proteases are commercially available, such as subtilisin Carlsberg, subtilisin BPN' and Savinase, with their major application as detergent enzymes. However, mutations have led to newer protease preparations with improved catalytic efficiency and better stability towards temperature, oxidizing agents and changing wash conditions. Many newer preparations, such as Durazym, Maxapem and Purafect, have been produced, using techniques of site-directed mutagenesis and/or random mutagenesis. Directed evolution has also paved the way to a great variety of subtilisin variants with better specificities and stability. Molecular imprinting through conditional lyophilization is coming up to match molecular approaches in protein engineering. There are many possibilities for modifying biocatalysts through molecular approaches. However, the search for microbial sources of novel alkaline proteases in natural diversity through the "metagenome" approach is targeting a hitherto undiscovered wealth of molecular diversity. This fascinating development will allow the biotechnological exploitation of uncultured microorganisms, which by far outnumber the species accessible by cultivation, regardless of the habitat. In this review, we discuss the types and sources of proteases, protease yield-improvement methods, the use of new methods for developing novel proteases and applications of alkaline proteases in industrial sectors, with an overview on the use of alkaline proteases in the detergent industry.

Amino Acid Sequence↗
PubMed2002

Silent brain infarcts are rare in Kuwaiti children with sickle cell disease and high Hb F.

Overt stroke is rare among sickle cell disease (SCD) patients in Kuwait. However, there are no previous studies of silent cerebral infarcts, which have been described in up to 20% of American children with Hb SS. We have carried out a prospective brain MRI study among otherwise normal SCD patients, who were consecutive patients seen in a 1-year period to document the prevalence of silent cerebral infarcts in children with sickle cell disease in Kuwait. Any patient with a previous seizure or other neurological abnormality was excluded. MRI was done with a 1.5 Tesla unit with super-conducting magnet. T1- and T2-weighted sagittal and axial sections and proton density axial images were obtained in 5-mm thick sections. The study group consisted of 30 (23 SS and 7 Sbeta(0)Thal) patients-19 males and 11 females-whose ages ranged from 6 to 17 (mean of 9.8 +/- 3.5) years. Hb F ranged from 11% to 35% with a mean of 22.8% +/- 5.7%. Only one patient, a 10-and-a-half-year-old boy with Hb SS, showed hyperintense signals in the parietal white matter, consistent with small infarcts, thus giving a prevalence of 3.3%. Silent brain infarcts are uncommon in our patients, and the protective factors remain to be fully elucidated.

Adolescent↗
PubMed2002

Pediatric urolithiasis in Kuwait.

In this retrospective study, 31 Kuwaiti children with renal stones were reviewed between January 1996 and September 2000. Male to Female ratio was 2.1:1 with a mean age at presentation of 38 months. Family history of renal stones was reported in 58%. Stones were localized to the kidneys in 74.1%, to ureters in 6% and to the bladder in 9.6%. Bilateral stones were found in 64.5%. Clinical manifestations included: hematuria in 70.9%, passage of stones in 64.5%, abdominal pain in 41.9%, urinary tract infections in 29%, sterile pyuria in 22.9% and urine retention in 16%. Causes of stone formation included hypercalciuria in 38.7%, hyperoxaluria in 19.3%, cystinuria in 12.9%, xanthinuria in 12.9%, urinary tract infection in 3.2%, obstruction in 9.6% and idiopathic in 3.2%. In conclusion, lithogenic metabolic causes were found to be the major predisposing factors to stone formation among Kuwaiti children whereas diet and environmental factors played a trivial role.

Age Distribution↗