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Biomedical subjects

D L Sewell

Publications and source records attributed to D L Sewell.

At least 37 records · Page 2Linked to original sources
PubMed1987

Immunoglobulin M to cytomegalovirus in primary and reactivation infections in renal transplant recipients.

Two commercially available enzyme immunoassays and one assembled in house were used to measure immunoglobulin M (IgM) antibody to cytomegalovirus (CMV) in a total of 220 serum specimens from 104 renal transplant recipients. All assays included a step in which interfering IgG antibody was removed or complexed. Concordance of results between pairs of assays ranged from 84 to 96%. All sera from patients with recent seroconversion (primary CMV infection) had measurable anti-CMV IgM. Among those already seropositive to CMV when transplanted, 26 to 55% had IgM antibody posttransplant, depending on the assay. This was observed regardless of the CMV serologic status of the kidney donor, indicating that reactivation of endogenous CMV, as well as reinfection, can induce this antibody in transplant recipients. Four cadaver donors known to transmit CMV to eight recipients did not have measurable IgM antibody to CMV.

Antibodies, Viral↗
PubMed1986

Screening for bacteriuria with the LN strip test.

Recently, the LN strip test was introduced for purposes of rapid screening of urine specimens for bacteriuria. The LN strip test permits detection of urinary leukocyte esterase and nitrite. A total of 2,481 unselected urine specimens from three tertiary care hospitals were examined using the LN strip test and the results were compared with those obtained with a conventional quantitative culture technique. When the results of the leukocyte esterase and nitrite tests were combined, the sensitivity and specificity of the LN strip test were 88.8% and 71.3%, respectively, based on culture results of greater than or equal to 10(5) CFU/ml. Test sensitivity decreased at greater than or equal to 10(4) CFU/ml, whereas test specificity increased.

Bacteriuria↗
PubMed1986

Quality control testing of anti-sera with glutaraldehyde-treated antigens.

Glutaraldehyde-treated bacterial cells were used as the quality control organisms in agglutination and fluorescent antibody tests for group A Streptococcus; Salmonella groups A, B, and D; Shigella groups B, C, and D; and Neisseria gonorrhoeae. The antigen preparations were serologically reactive over a period of five months.

Aldehydes↗
PubMed1985

Evaluation of the Chemstrip 9 as a screening test for urinalysis and urine culture in men.

The Chemstrip 9 (Biodynamics, Inc., Indianapolis, IN) was evaluated as a rapid screening method for urinalysis and quantitative urine culture. Of 469 urine specimens, 224 had an abnormal microscopic examination compared to 211 with an abnormal Chemstrip 9 (i.e., leukocyte esterase, nitrite, protein, or blood). The sensitivity and specificity of the dipstick test were 94.2% and 65.7%, respectively, while the predictive values of a positive and negative test were 71.5% and 92.5%, respectively. A total of 459 urine specimens were quantitatively cultured and tested by the Chemstrip 9. Either one or more tests (i.e., leukocyte esterase, nitrite, protein, or blood) were positive in 91.3% of the 115 specimens with greater than or equal to 10(5) CFU/mL. The specificity was 43.6% and the predictive values of a positive and negative test were 35.1% and 93.8%, respectively. When the criterion for a positive test was greater than or equal to 10(4) CFU/mL, the sensitivity and specificity were 86.8% and 45.5%, respectively. In contrast, the gram-stained smear of unspun urine was positive in 107 (93.0%) of specimens containing greater than or equal to 10(5) CFU/mL and in 115 (76.2%) of specimens with greater than or equal to 10(4) CFU/mL. Only 9 (2.9%) of 308 specimens with less than or equal to 10(3) CFU/mL had a positive Gram smear.

Bacteriological Techniques↗
PubMed1985

Evaluation of a commercial enzyme-linked immunosorbent assay for the detection of herpes simplex virus.

A total of 136 specimens were tested for the presence of herpes simplex virus by routine tissue culture and a commercial enzyme-linked immunosorbent assay (Ortho Diagnostic Systems, Inc.). Forty-six (33.8%) of the specimens were positive by tissue culture. The sensitivity and specificity of the commercial system were 69.6 and 93.3%, respectively. The commercial system was rapid and moderately specific but lacked the sensitivity necessary for direct specimen testing.

Antigens, Viral↗
PubMed1984

Incomplete activation of intraperitoneal clindamycin phosphate during peritoneal dialysis.

Clindamycin phosphate (C-PO4) must be hydrolyzed to the active antibiotic, but whether this occurs within the peritoneal cavity during peritoneal dialysis is unknown. Therapeutic peritoneal levels are difficult to achieve after intravenous administration, so direct intraperitoneal instillation is preferred in treating dialysis-associated peritonitis. Therefore, the activation of C-PO4 in peritoneal dialysate was investigated. Fresh and 'uremic' peritoneal dialysates of 1.5 and 4.25% dextrose concentrations at pHs of 5.1 and 7.4 did not activate C-PO4. Clindamycin hydrochloride in this same fluid was active, ruling out uremic deactivators. A patient with peritonitis was treated with intraperitoneal C-PO4, and therapeutic (greater than 5 micrograms/ml) serum and peritoneal levels were achieved. Infected (exudative) peritoneal dialysate drained from another patient with peritonitis activated C-PO4 in vitro. Commercial alkaline phosphatase added to uremic dialysate also activated C-PO4 in vitro. C-PO4 was instilled into the peritoneal cavities of 10 noninfected patients. Exposure to the peritoneal membrane at two concentrations resulted in a 3% activation of C-PO4. From these observations it is clear that C-PO4 is only partially activated intraperitoneally. Uremia or uremic products in the dialysate do not deactivate the antibiotic. Exudative material (bacteria, white blood cells and proteins) in infected dialysate contribute to activation of C-PO4. The peritoneal membrane further assists in activation. We recommend that C-PO4 be administered at a concentration of 167 mg/l of dialysate to ensure therapeutic peritoneal levels of the active antibiotic, especially after the exudative phase clears.

Alkaline Phosphatase↗
PubMed1983

Stability of single and combination antimicrobial agents in various peritoneal dialysates in the presence of insulin and heparin.

The antimicrobial activity of ampicillin, azlocillin, cefotaxime, cephapirin, clindamycin, mezlocillin, nafcillin, piperacillin, tobramycin, and vancomycin was tested in peritoneal dialysate at room temperature for 24 hours and 48 hours. All of the antimicrobial agents were active at 24 hours. The bioactivity of cefotaxime, nafcillin, and vancomycin declined 15% to 20% after 48 hours (P less than 0.001). The addition of heparin or insulin did not affect the activity of any of the study drugs. The combination of cephapirin and tobramycin remained bioactive for 24 hours at room temperature and 35 degrees C. The preparation of drug-dialysate solution every one to two days is feasible for the treatment of peritonitis in patients on continuous ambulatory or continuous cycled peritoneal dialysis.

Anti-Bacterial Agents↗
PubMed1983

Case report: potential error in the estimation of antimicrobic concentrations by the microbiological assay method.

An 83-year-old man was admitted for gastrointestinal bleeding that required a segmental colectomy for correction. The patient was initially treated with gentamicin, clindamycin, and cephapirin for sepsis. Antibiotic coverage was changed to amikacin, clindamycin, and penicillin G for sepsis and anaerobic cellulitis. When renal function began to deteriorate, serum amikacin levels were determined by a radioenzymatic and bioassay method. The serum concentration of amikacin in the presence of penicillin G and clindamycin was overestimated when a multiantimicrobic-resistant Escherichia coli was used as the indicator organism in the microbiological assay.

Aged↗
PubMed1982

Stability of antimicrobial agents in peritoneal dialysate.

The stability of cephapirin, gentamicin, penicillin G, nafcillin, ticarcillin, and vancomycin was tested in peritoneal dialysate at 25 degrees C for 24 h. All of the antimicrobial agents were stable except penicillin G, which lost 25% of activity over 24 h (P less than 0.01). The once-daily preparation of drug-dialysate solution is feasible for the treatment of peritonitis in patients on continuous ambulatory peritoneal dialysis.

Anti-Bacterial Agents↗
PubMed1981

Clinical evaluation of the Abbott MS-2 antimicrobial susceptibility testing system.

Antimicrobial susceptibilities were determined for 845 clinical isolates by the standardized Bauer-Kirby disk diffusion method and the automated Abbott Ms-2 system. There was an overall correlation of 90% between the two methods. The Abbott MS-2 susceptibility instrument offers a rapid and accurate method for the antimicrobial susceptibility testing of bacteria.

Anti-Bacterial Agents↗
PubMed1976

Glucose tolerance, insulin and catecholamine levels in germfree rats.

Glucose was administered intravenously to 50- and 100-day-old GF and CV rats. Fasting blood glucose levels in GF and CV rats were found to be comparable. Glucose tolerance tests showed that GF and CV rats clear glucose from the blood at a similar rate. Although insulin concentrations in 100-day-old GF rats tended to be somewhat lower than in CV rats, the percentage increase during the 30-min period after glucose administration was similar, and matched the increase in blood glucose. Levels of plasma catecholamines were analyzed fluorometrically and were found to be comparable in 100-day-old GF and CV rats. It was concluded that insulin insufficiency plays no role in the syndrome of metabolic anomalies demonstrated by the germfree rat.

Age Factors↗
PubMed1975

Thyroid function and related hepatic enzymes in the germfree rat.

The adult germfree rat has a low metabolic rate, and the activity of various hepatic enzymes differs substantially from values found in the conventional animal. To promote understanding of the shifts in intermediary metabolism apparent in the germfree rodent, parameters of thyroid function and the activity of three enzyme systems presumably influenced by thyroid function were determined in 40-, 60-, and 100-day-old male germfree and conventional Lobund rats of Wistar origin. Serum thyroxine concentrations generally increased with age. They were below normal levels in 40- and 60-day-old germfree rats but appeared normal in the 100-day-old germfree animal. Serum thyroxine-binding protein saturation levels were significantly reduced in germfree rats of all age groups, but the reduction was least in the 100-day-old group. Mitochondrial succinate oxidase and alpha-glycerophosphate dehydrogenase activities were lower in livers of germfree rats of all age groups, although the significance of the difference in succinic oxidase activity became less in older animals. Monoamine oxidase activity was similar in germfree and conventional animals. Although the data suggest a hypofunction of the thyroid in the immature germfree rat, no definite relation between thyroid function and the characteristic metabolic anomalies of the germfree rat could be established.

Animals↗
PubMed1975

Oxidative energy metabolism in germ-free and conventional rat liver mitochondria.

The ADP:O ratios and State 3 (ADP-stimulated) and State 4 (controlled) rates of succinate, beta-hydroxybutyrate, isocitrate, glutamate, pyruvate + malate, alpha-ketoglutarate, and ascorbate + N,N,N',N'-tetramethylphenylenediamine (TMPD) oxidation were examined in liver mitochondria from germ-free and conventional rats of both Lobund Wistar (100-day-old) and Fisher (120-day-old) strains. The State 3 respiration rates of isolated mitochondria from germ-free and conventional rats were comparable except for the rate of succinate oxidation in the Wistar rats, which was significantly lower (approx. 10%). The State 4 respiration rates were generally lower in mitochondria isolated from germ-free Fisher rats (approx. 8%) and significantly lower (approx. 18%) in germ-free Wistar rats. The ADP:O ratios were similar in germ-free and conventional rats. Serum thyroxine concentrations indicated delayed maturation of thyroid function in young germ-free rats, but adult animals had concentrations similar to those found in conventional rats. The results indicate that, although absence of a microflora results in a 20-30% reduction in metabolic rate, the germ-free state has little influence on the functional respiration or oxidative phosphorylation of mitochondria isolated from the liver of the adult rat.

Adenosine Diphosphate↗