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Biomedical subjects

K M Patel

Publications and source records attributed to K M Patel.

72 records · Page 4Linked to original sources
PubMed1979

Biophysical properties of a major membrane phospholipid, dielaidoylphosphatidylethanolamine, found in an Escherichia coli fatty acid auxotroph.

Dielaidoylphosphatidylethanolamine, a principal lipid component of membranes of Escherichia coli fatty acid auxotrophs enriched in elaidic acid, has been studied by paramagnetic resonance, fluorescence, and calorimetric methods. EPR measurements with perdeutero-di-tert-butylnitroxide and 2,2,6,6-tetramethyl piperidine-1-oxyl indicate that, when dispersed in aqueous media, this phospholipid undergoes an abrupt order leads to disorder transition at 37.5 degrees C and 36.5 C, respectively. A similar transition temperature is suggested by experiments with 9-doxyl-dimyristoylphosphatidylethanolamine (DEPE). cis- and trans-Parinaric-acid fluorescence polarization measurements indicate that the midpoint of this transition occurs at 34.0 degrees C and 35.5 degrees C, respectively. Differential scanning calorimetry of DEPE revealed a single, sharp endotherm at 38.5 degrees C with increasing temperature; two exotherms of similar magnitude were observed at 36.5 degrees C and 34.5 degrees C upon cooling. This double transition was not observed by any of the other methods. From these results we conclude that the major structural transition at 30-31 degrees C observed previously with 5-, 12-, and 16-doxyl stearate in intact E. coli membranes is due to the DEPE present (Morrisett, J.D., Pownall, H.J., Plumlee, R.T., Smith, L.C., Zehner, Z.E., Esfahani, M., and Wakil, S.J. (1975) J. Biol. Chem. 250, 6969-6976).

Calorimetry, Differential Scanning↗
PubMed1979

Antimicrobial activity of chlormerodrin.

A radiochemical study for antimicrobial activity of chlormerodrin was performed using some commonly occurring nonpathogenic and pathogenic microorganisms. Chlormerodrin concentrations of 15-35 and 20-45 microgram/ml of the culture medium were microbiostatic and microbicidal, respectively. The microbiostatic effect was reversible in the presence of cysteine, an amino acid containing a sulfhydryl group.

Anti-Infective Agents↗
PubMed1979

A convenient synthesis of phosphatidylcholines: acylation of sn-glycero-3-phosphocholine with fatty acid anhydride and 4-pyrrolidinopyridine.

A high-yield synthesis of saturated, unsaturated, and short chain phosphatidylcholines from sn-glycero-3-phosphocholine is described. The procedure offers advantages over other reported procedures for the synthesis of phosphatidylcholine in that the large-scale synthesis and purification can be achieved in a minimum time. The procedure utilizes 4-pyrrolidinopyridine as a catalyst and moderate amounts of fatty acid anhydride (2 mol eq. of fatty acid anhydride per mol of OH) in a 1:1 mixture of benzene-dimethylsulfoxide (DMSO) at 40 degrees--42 degrees C (oilbath) for 2--5 hr. At the end of the reaction, the phosphatidylcholine can be purified in the usual manner or by using a Waters Prep LC/500 with a radially compressed silica gel column eluted with chloroform-methanol-water 60:30:4. At a flow rate of 200 ml/min, the phospholipid elutes in 10--15 min, depending on the chain length and unsaturation.

Acylation↗
PubMed1974

Structure of some cyclohexyl compounds as related to their ability to stimulate plant growth.

Aqueous solution, 10 mm, of cyclohexanecarboxylic, cyclohexylacetic, cyclohexylpropionic, cyclohexylbutyric acids (all components of naphthenic acid); cis-1,2-, and trans-1, 4-cyclohexyldicarboxylic acids; 3-cyclohexene-1-carboxylic and cyclohexylsulfamic acids; and cyclohexyl mercaptan were applied to 14-day-old bush bean plants, Phaseolus vulgaris L. cv. Top Crop. Only cyclohexanecarboxylic and cyclohexylacetic acid resulted in a statistically significant (P = 0.05) increase in pod production per plant in all experiments. The stimulation by the first four monocarboxylic acids decreased as the number of methylene groups in the side chain increased from 0 to 3. The effective compounds possessed an H-saturated 6-carbon ring with a single carboxyl group attached directly to the ring or separated from it by no more than one methylene group.

Journal Article↗
PubMed1968

Intraperitoneal blood transfusion in African adults with hookworm anaemia.

Twenty-nine patients were given an intraperitoneal transfusion of blood. The procedure was found to be free of serious complications. Study of the absorption of an (51)Cr-labelled cells from the peritoneum in 14 patients showed that between 35 and 100% of the blood was absorbed intact in 6 to 10 days. Intraperitoneal transfusion may be indicated as an alternative or as an addition to exchange transfusion in severe hookworm anaemia.

Absorption↗
PubMedDate not supplied

The epidemiology of Kawasaki disease in an urban hospital: does African American race protect against coronary artery aneurysms?

The etiology and pathogenesis of Kawasaki disease (KD) is largely unknown. Certain demographic factors and laboratory findings are predictive of the development of coronary artery (CA) aneurysms. The objectives of this study were to determine the epidemiology of KD patients in an urban hospital and determine risk factors associated with their development of CA abnormalities. A longitudinal case series of KD patients admitted to Children's National Medical Center from 1990 to 2002 was examined. Age, sex, ethnic background, duration of fever prior to diagnosis, address, month diagnosed, and CA abnormalities (ectasia or aneurysms) on echocardiography were recorded. Median household income was obtained from the U.S. Census Bureau Web site. The Student t-test, logistic regression analyses, and the Kruskal-Wallis test were used, with significance assumed at p < 0.05. A total of 302 patients were evaluated. CA abnormalties were found in 27 patients (9%), with aneurysms identified in 13 patients (4%). Age was 2.9 +/- 2.4 years (range, 2 months to 14 years). A total of 51 patients (16%) were < or =1 year and 35 patients (12%) were > or =5 years. Ethnic distribution was 54% (164) African American, 24% (72) Caucasian, 9% (29) Asian/Pacific Islander, 8% (23) Hispanic, and 5% (14) Middle Eastern. Only 2/164 (1.2%) African Americans developed CA aneurysms. Neighborhood median income of the cohort was $45,400 +/- $21,200 ($52,200 +/-$25,800 for patients with aneurysms). A total of 28% of cases clustered between December and January. Cases doubled annually in 1999-2001 compared to 1990-1998 (39 vs 19). Multivariate logistic regression found age between 1 and 5 years [p = 0.045; odds ratio, 0.31; 95% confidence interval (CI), 0.10-0.97] and African American race (p = 0.014; odds ratio, 0.15; 95% CI, 0.03-0.68) to be independently protective against CA aneurysms. Duration of fever prior to diagnosis, considered in 210 patients, was different between patients with and without aneurysms (11 +/- 5.3 vs 6.5 +/- 3.8 days, respectively, p = 0.0007). Multivariate logistic regression found fever longer than 5 days to be the only predictive factor associated with the development of aneurysms and any abnormality. African Americans had a shorter duration of fever than the rest of the cohort (6.03 vs 7.31 days), (p = 0.0087). The epidemiology of KD at our hospital is similar to that at other centers except for the predominance of African Americans with a shorter duration of fever prior to diagnosis and a decreased incidence of CA aneurysms compared to other ethnicities. The protective nature of African American ethnicity against the development of CA aneurysms raises speculation about the role of genetics and its interaction with immunity in the pathogenesis of KD.

Adolescent↗
PubMedDate not supplied

Peripheral venous access ports: outcomes analysis in 109 patients.

PURPOSE: To perform a retrospective outcomes analysis of central venous catheters with peripheral venous access ports, with comparison to published data. METHODS: One hundred and twelve central venous catheters with peripherally placed access ports were placed under sonographic guidance in 109 patients over a 4-year period. Ports were placed for the administration of chemotherapy, hyperalimentation, long-term antibiotic therapy, gamma-globulin therapy, and frequent blood sampling. A vein in the upper arm was accessed in each case and the catheter was passed to the superior vena cava or right atrium. Povidone iodine skin preparation was used in the first 65 port insertions. A combination of Iodophor solution and povidone iodine solution was used in the last 47 port insertions. Forty patients received low-dose (1 mg) warfarin sodium beginning the day after port insertion. Three patients received higher doses of warfarin sodium for preexistent venous thrombosis. Catheter performance and complications were assessed and compared with published data. RESULTS: Access into the basilic or brachial veins was obtained in all cases. Ports remained functional for a total of 28,936 patient days. The port functioned in 50% of patients until completion of therapy, or the patient's expiration. Ports were removed prior to completion of therapy in 18% of patients. Eleven patients (9.9% of ports placed) suffered an infectious complication (0.38 per thousand catheter-days)-in nine, at the port implantation site, in two along the catheter. In all 11 instances the port was removed. Port pocket infection in the early postoperative period occurred in three patients (4.7%) receiving a Betadine prep vs two patients (4.2%) receiving a standard O.R. prep. This difference was not statistically significant (p = 0.9). Venous thrombosis occurred in three patients (6.8%) receiving warfarin sodium and in two patients (3%) not receiving warfarin sodium. This difference was not statistically significant (p = 0.6). Aspiration occlusion occurred in 13 patients (11.7%). Intracatheter urokinase was infused in eight of these patients and successfully restored catheter function in all but two instances. These complication rates are comparable to or better than those reported with chest ports. CONCLUSION: Peripheral ports for long-term central venous access placed by interventional radiologists in the interventional radiology suite are as safe and as effective as chest ports.

Adult↗
PubMedDate not supplied

Donor-specific transfusions. Donor-recipient HLA compatibility, recipient HLA haplotype, and antibody production.

HLA profiles of 25 donor-specific transfusion (DST) kidney donor-recipient pairs were analyzed for HLA antigen compatibility. Serum samples collected during and after DST were tested for cytotoxic antibodies against T and B lymphocytes of the donors and 30 normal individuals. Eleven recipients did not produce cytotoxic antibodies to the antigens of their DST donors, and eight produced cold and/or warm, broadly reactive B-cell antibodies. Six patients (24%) produced HLA-A, B, C, and/or DR antibodies. Three of these individuals produced antibodies after two immunizations, while others required three immunizations. Three of the 11 antibody nonproducers (17%) had not received previous transfusions, as compared to three of the eight antibody producers (43%). Comparison of HLA profiles revealed 22 percent of the HLA-A, B, DR identities between the transfusion donor and recipient in antibody nonproducers as compared to 9 percent of the HLA-A, B, DR identities in antibody producers. The HLA-A2, B40, DR4 haplotype and HLA-DRW6 antigen were more common among antibody producers than among nonproducers, who had an excess of the HLA-B8, DR3 haplotype. These results are consistent with the hypothesis that there may be high- and low-responder HLA haplotypes that control immunologic responsiveness to histocompatibility antigens.

Adult↗