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Biomedical subjects

R Dave

Publications and source records attributed to R Dave.

At least 19 recordsLinked to original sources

Major advances in concentrated and dry milk products, cheese, and milk fat-based spreads.

Advances in dairy foods and dairy foods processing since 1981 have influenced consumers and processors of dairy products. Consumer benefits include dairy products with enhanced nutrition and product functionality for specific applications. Processors convert raw milk to finished product with improved efficiencies and have developed processing technologies to improve traditional products and to introduce new products for expanding the dairy foods market. Membrane processing evolved from a laboratory technique to a major industrial process for milk and whey processing. Ultra-filtration and reverse osmosis have been used extensively in fractionation of milk and whey components. Advances in cheese manufacturing methods have included mechanization of the making process. Membrane processing has allowed uniform composition of the cheese milk and starter cultures have become more predictable. Cheese vats have become larger and enclosed as well as computer controlled. Researchers have learned to control many of the functional properties of cheese by understanding the role of fat and calcium distribution, as bound or unbound, in the cheese matrix. Processed cheese (cheese, foods, spreads, and products) maintain their importance in the industry as many product types can be produced to meet market needs and provide stable products for an extended shelf life. Cheese delivers concentrated nutrients of milk and bio-active peptides to consumers. The technologies for the production of concentrated and dried milk and whey products have not changed greatly in the last 25 yr. The size and efficiencies of the equipment have increased. Use of reverse osmosis in place of vacuum condensing has been proposed. Modifying the fatty acid composition of milkfat to alter the nutritional and functional properties of dairy spread has been a focus of research in the last 2 decades. Conjugated linoleic acid, which can be increased in milkfat by alteration of the cow's diet, has been reported to have anticancer, anti-atherogenic, antidiabetic, and antiobesity effects for human health. Separating milk fat into fractions has been accomplished to provide specific fractions to improve butter spreadability, modulate chocolate meltability, and provide texture for low-fat cheeses.

Animals↗

Gamma-fluorinated analogues of glutamic acid and glutamine.

Gamma-fluorinated analogues of glutamic acid and glutamine are compounds of biological interest. Syntheses of such compounds are extensively reviewed in this article. 4-fluoroglutamic acid was prepared as a mixture of racemic diastereomers by Michael reaction, inverse-Michael reaction or by electrophilic / nucleophilic fluorination. Optically enriched 4-fluoroglutamic acids were obtained by several resolution techniques as well as by asymmetric methodologies using the chiral pool. 4-fluoroglutamine was prepared as a mixture of stereoisomers as well as in racemic erythro and threo forms from the corresponding 4-fluoroglutamic acids using aminolysis and conventional protection and deprotection strategies. Racemic 4,4-difluoroglutamic acid was synthesized by a nitroaldol reaction and its L-enantiomer obtained via three different asymmetric routes. Racemic 4,4-difluoroglutamic acid was converted into the corresponding 4,4-difluoroglutamine using a protection / aminolysis / deprotection sequence while N-Boc-L-4,4-difluoroglutamine was prepared directly from (R)-Garner's aldehyde using a Reformatsky reaction as the key step.

Fluorine↗

Isolation of primary HIV-1 that target CD8+ T lymphocytes using CD8 as a receptor.

HIV-1 use CD4 receptors to infect their primary targets, CD4+ cells, whereas CD8+ cells have a protective role against HIV-1. We recently isolated HIV-1-producing CD8+ clones from two AIDS patients. Here we show that although HIV-1 produced by CD8+ cells maintained the ability to infect CD4+ cells, these viruses were able to infect CD8+ cells independent of CD4. Evidence indicates that these viruses used CD8 as a receptor to infect CD8+ cells. First, expression of CD8 was downmodulated after infection. Second, anti-CD8 antibodies blocked viral entry and replication in CD8+ cells. Finally, resistant cells became susceptible after expression of CD8. Although these viruses used CXCR4 to enter CD4+ cells, it seems that infection of CD8+ cells was independent of CXCR4 or CCR5 co-receptors. Novel changes were observed in envelope sequences of CD8-tropic viruses. These results provide initial evidence that HIV-1 can mutate to infect CD8+ cells using CD8 as a receptor.

Amino Acid Sequence↗

Prospective study of outcome in antenatally diagnosed renal pelvis dilatation.

AIMS: To ascertain the outcome associated with antenatal renal pelvis dilatation; to recommend guidelines for postnatal investigation and determine an upper limit of normal for the anterioposterior dimensions of the fetal renal pelvis. METHODS: Infants whose antenatal ultrasound scan showed a fetal renal pelvis of 5 mm or greater were investigated using postnatal renal tract ultrasound and a micturating cystogram. Isotope studies were also performed, where appropriate. RESULTS: Vesicoureteric reflux (VUR), the most common diagnosis, was evident in 23/104 (22%). In 14 infants with VUR the postnatal ultrasound scan was normal. There was no evidence of renal scarring or dysplasia in any of the refluxing kidneys. Other diagnoses were pelviureteric junction obstruction, renal dysplasia, and idiopathic dilatation. Antenatal counselling and parental information facilitated postnatal assessment. CONCLUSIONS: Infants with antenatal renal pelvis measurements of 5 mm or greater should be investigated postnatally, as a significant percentage will have VUR. A normal postnatal ultrasound scan does not preclude the presence of VUR.

Female↗

Dermatomycosis in and around Aurangabad.

A total of 175 cases of dermatophytoses were studied. Out of all the clinical types, Tinea corporis (T. corporis) was found to be the predominant clinical type (24.57%) followed by tinea cruris (T. cruris) (22.28%). Incidence of Tinea barbae (T. barbae) and Tinea imbricata (T. imbricata) was the least (2.85%) and 0.57% respectively. Out of 175 cases of dermatophytoses, 66 (37.71%) cases were positive on microscopic examination, out of which 27 (40.90%) cases were positive by culture also. Out of the 175 cases of dermatophytoses, 109 (62.28%) were engative on microscopic examination, out of which 13 (11.92%) were culture positive. In this study, Trichophyton was the commonest genus of dermatophyte isolated, with Trichophyton rubrum (T. rubrum) being the commonest species (28.12%), followed by Trichophyton mentagrophyte. (T. mentagrophyte) (25.0%) Trichophyton soudanense (T. soundanense), which is a rare species (not reported from any studies) was isolated from cases of T. corporis and T. cruris.

Adolescent↗

Arterial injury by cholesterol oxidation products causes endothelial dysfunction and arterial wall cholesterol accumulation.

Cholesterol oxidation products (ChOx) have been reported to cause acute vascular injury in vivo; however, the pharmacokinetics of ChOx after administration and the mechanisms by which they cause chronic vascular injury are not well understood. To further study the pharmacokinetics and atherogenic properties of ChOx, New Zealand White rabbits were injected intravenously (70 mg per injection, 20 injections per animal) with a ChOx mixture having a composition similar to that found in vivo during a 70-day period. Total ChOx concentrations in plasma peaked almost immediately after a single injection, declined rapidly, and returned to preinjection levels in 2 hours. After multiple injections, the ChOx concentrations rose gradually to levels 2- to 3-fold above baseline levels, increasing mostly in the cholesteryl ester fraction of LDL and VLDL. Rabbit serum and the isolated LDL/VLDL fraction containing elevated ChOx concentrations were cytotoxic to V79 fibroblasts and rabbit aortic endothelial cells. At the time of killing, cholesterol levels in the aortas from ChOx-injected rabbits were significantly elevated despite the fact that plasma cholesterol levels remained in the normal range. In addition, aortas from the ChOx-injected rabbits retained more 125I-labeled horseradish peroxidase, measured 20 minutes after intravenous injection. Transmural concentration profiles across the arterial wall also showed increased horseradish peroxidase accumulation in the inner half of the media from the thoracic aorta in ChOx-injected rabbits. In conclusion, ChOx injection resulted in accumulation of circulating ChOx and induced increased vascular permeability and accumulation of lipids and macromolecules. This study reveals that even under normocholesterolemic conditions, ChOx can cause endothelial dysfunction, increased macromolecular permeability, and increased cholesterol accumulation, parameters believed to be involved in the development of early atherosclerotic lesions.

Animals↗

Prolonged survival after massive pulmonary embolism in a patient with atrial septal defect and mass in the right ventricle.

Unless thrombolytic or surgical therapy is rapidly available, massive pulmonary embolism in both pulmonary arteries invariably results in instantaneous death. A patient is presented with congenital atrial septal defect and right ventricular thrombus who developed extensive bilateral pulmonary embolism with an apparently prolonged survival. The ante- and postmortem findings represent the unusual and interesting aspects of this particular case.

Acute Disease↗

Ability of the no-reflow phenomenon during an acute myocardial infarction to predict left ventricular dysfunction at one-month follow-up.

Despite angiographically successful opening of an infarct-related vessel within a 6-hour time frame, some patients do not recover left ventricular regional wall function in the infarct zone after an acute myocardial infarction (AMI). Recent evidence suggests that this finding is due to the no-reflow phenomenon, or failure to recover tissue perfusion despite patient epicardial arteries. We performed myocardial contrast echocardiography to assess tissue perfusion before and after opening of an infarct-related artery. Coronary angiograms, regional wall motion scoring, and myocardial contrast enhancement were graded by 3 observers. Of 24 patients with AMI, 7 (29%) failed to recover tissue perfusion in > or = 1 region of myocardium. Of 106 regions subtended by the infarct-related artery, 16 (15%), 43 (41%), and 47 (44%) regions had no-reflow, partial, or normal flow, respectively, after arterial patency was established. There was a spectrum of reperfusion patterns ranging from no-reflow to normal perfusion. One-month follow-up angiographic and myocardial contrast echocardiographic studies were performed in 12 of the 24 patients. At 1 month, all segments of myocardium that had immediate normal perfusion had regained normal wall motion. In contrast, 17 segments that had partial or no-reflow were identified. Of these 17, 3 regained normal function, 10 segments were hypokinetic, and 4 segments were akinetic. We conclude that myocardial contrast echocardiography can be used to identify the no-reflow phenomenon in up to 29% of patients with AMI. Additionally, we found that the immediate-reflow pattern can predict degree of left ventricular dysfunction at 1-month follow-up.

Adult↗

Interrelationship of prolactin and its receptor in carcinoma of colon and rectum: a preliminary report.

The prolactin receptors (PRLR) were correlated with circulating prolactin and various clinicopathologic parameters to investigate its prognostic value in patients with colorectal cancer. The prolactin (by radioimmunoassay) and its receptors (by radioligand method) were estimated in a total of 71 male patients with colorectal cancer enrolled at the Gujarat Cancer and Research Institute, Ahmedabad. The patients were followed for a period of 3 years. We have observed that 51% colorectal tumors were PRLR+. Significant correlation was not observed between presence/absence of PRLR and clinicopathologic variables. Dukes' D patients were lost to follow-up after 2-3 months; therefore, the results of prognostic significance were analysed only in patients with Dukes' A, B, and C (N = 64). Statistically significant difference in overall survival was not observed when the patients were subgrouped according to the presence/absence of PRLR and according to the cutoff level (i.e., 2%). PRLR+ hyperprolactinemic (Prolactin > 20.0 ng/ml plasma) patients had better overall survival than that of patients with PRLR- hyperprolactinemia, although the difference was statistically nonsignificant. However, PRLR- hyperprolactinemia patients had a more unfavourable prognosis than that of their counterparts. A similar trend was observed in patients with Dukes' B and C disease. Our preliminary study suggests an unequivocal finding, that PRLR- with concomitant hyperprolactinemia probably characterises a subgroup of patients with aggressive colorectal cancer.

Adult↗

Contrast echocardiography.

Myocardial contrast echocardiography (MCE) is an ultrasound imaging technique which promises to provide a safe, noninvasive means of assessing myocardial perfusion. A contrast agent, consisting of a suspension of air-filled microspheres, serves as an ultrasound tracer. When these microspheres are injected intravascularly, the acoustic interface created between the blood and the microspheres enhances the reflected ultrasound signals. Thus, the flow pattern of the microspheres represent the actual blood flow patterns. This paper will review the field of contrast echocardiography, its background and history, the development of ultrasound contrast agents, and a variety of experimental as well as clinical uses. Contrast echocardiography has been utilized in the cardiac catheterization laboratory for the assessment of "risk area," assessment of collateral blood flow and assessment of coronary blood reserve. In the operating room, contrast echo is utilized for the determination of cardioplegic perfusion, assessment of graft patency and evaluation of valvular regurgitation. In the future, with the technical advancement in ultrasound imaging and the active interest and growth in the field of myocardial perfusion imaging using contrast echocardiography, the ability to provide routine real-time perfusion imaging may become a reality.

Albumins↗

Transfer of embryos into the uterus: how much do technical factors affect pregnancy rates?

OBJECTIVE: Our objective was to identify the effect on outcome of (a) ultrasound-assisted embryo transfer, (b) the use of different embryo transfer catheters, and (c) the length of time the patients remain in the supine position after embryo transfer. SETTING: The setting was a private fertility center. SUBJECTS: This was a prospective study of 178 in vitro fertilization and embryo transfers (IVF-ET) and 63 frozen embryo replacements (FER). RESULTS: The pregnancy rate was 28.7% following IVF-ET and 31.8% for FER. Ultrasound-assisted transfer did not affect the outcome (29 vs 30.3%). There was no difference in the performance of the Wallace and Frydman catheters with regard to outcome (30.3 vs 30.7%). Although there was an increase in pregnancy rate as the time interval in the supine position after ET increased, this needs a larger study. CONCLUSION: The parameter studies did not affect the outcome of IVF/ET or FER. Some factors encouraged us to recommend ultrasound-assisted transfer in some cases, and the use of a Frydman catheter for transfer and to encourage the supine position after transfer for longer periods.

Abdomen↗