PubMed Health⌕ Search

Biomedical subjects

D Sullivan

Publications and source records attributed to D Sullivan.

At least 19 recordsLinked to original sources
PubMed1995

Insulin resistance is associated with abnormal dephosphorylation of a synthetic phosphopeptide corresponding to the major autophosphorylation sites of the insulin receptor.

Insulin resistance in the ob/ob mouse model is associated with a reduction in insulin-induced protein-tyrosine phosphorylation in tissues such as liver. To ascertain whether this decrease in phosphorylation may be due to increased phosphatase activity, protein-tyrosine phosphatase (PTPase) activity was determined in particulate and soluble fractions from livers of 5- to 23-week-old ob/ob mice and age-matched lean littermates. PTPase activity was measured using a synthetic phosphopeptide, TRDIY(P)ETDY(P)Y(P)RK, as the substrate, corresponding to residues 1142 to 1153 of the insulin receptor and containing the major autophosphorylation sites of the regulatory domain. The ob/ob mice were hyperinsulinemic across all age groups, but only the youngest mice (aged 5 to 7 weeks) were hyperglycemic. Most PTPase activity was present in the liver particulate fraction and was 19% to 114% greater in ob/ob mice as compared with controls. PTPase activity in the liver soluble fraction was 26% less than control values in the youngest ob/ob mice (5 to 7 weeks), but increased with age and was 41% and 131% above control values at 21 to 23 and 25 to 27 weeks of age, respectively. Oral administration of the PTPase inhibitor sodium orthovanadate (0.6 mg/mL in drinking water for 2 weeks) to young ob/ob mice caused a significant reduction in the elevated particulate PTPase activity, with concomitant decreases in plasma insulin and plasma glucose. Assessment of PTPase activity with a monophosphate form of the same synthetic peptide, TRDIY(P)ETDYYRK, showed lower PTPase activities as compared with the triphosphate form and no significant differences between ob/ob and control preparations.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1994

Benchmarking: finding ways to improve.

BACKGROUND: This article provides health care organizations with a benchmarking methodology to use in comparing practices and processes to identify and actualize opportunities for improvement. The 15-step model can be used to guide internal and external benchmarking activities in a variety of health care settings. EXAMPLES: Two internal benchmarking case studies are illustrated: (1) one hospital used the Baxter model to evaluate its laparoscopic cholecystectomy services, and (2) another prepared for expansion of cardiac catheterization services. CONCLUSIONS: Two key factors of a successful benchmarking initiative are highlighted: management commitment and involvement, and the need to understand internal practices and processes before benchmarking.

Cholecystectomy, Laparoscopic↗
PubMed1994

Use of DNA fingerprinting and biotyping methods to study a Candida albicans outbreak in a neonatal intensive care unit.

During a 15-day period, 7 premature infants hospitalized in a neonatal intensive care unit presented with sepsis caused by Candida albicans. The local environment and hands of all 54 persons involved in the intensive care unit were examined for the presence of this organism. Five techniques were used in the analysis of the isolates recovered from blood cultures of the children, the hands of personnel and 10 control isolates. The methods used were serotype determination, genetic fingerprinting, morphotyping, resistotyping and killer yeast typing. Morphotyping and genetic fingerprinting proved to be the most discriminatory techniques, and only combined analysis of the results obtained with these various methods allowed the source of the outbreak to be identified. An isolate from the hands of a healthy staff member and isolates from infected children all belonged to the same strain.

Adult↗
PubMed1994

Cholesterol and non-cardiovascular disease: basic science.

Cholesterol metabolism is of fundamental biological importance. This review examines the role of cholesterol metabolism in relation to non-cardiovascular disease (non-CVD). Particular attention is paid to the question of whether or not low levels of cholesterol may have harmful effects on cell function or lead to pathological processes. Many in vitro phenomena have been demonstrated at levels of cholesterol which are very low in comparison to physiological conditions. Nevertheless, low cholesterol is more favourable than high cholesterol for most aspects of cell function. There is no evidence that any catastrophic cellular response or pathological process occurs due to exposure of organisms to low cholesterol. On the other hand, the inflammatory process is a powerful and consistent cause of decreased cholesterol levels. This, together with other confounding factors, appears to explain a major component of the association between low cholesterol levels and non-CVD.

Cell Division↗
PubMed1994

In situ hybridization and the polymerase chain reaction (PCR) in the analysis of biopsies and exfoliative cytology specimens for definitive diagnosis of oral hairy leukoplakia (OHL).

The definitive diagnosis of oral hairy leukoplakia (OHL) demands that Epstein-Barr virus (EBV) is demonstrated in the lesional tissue, since the histopathological features on conventional light microscopy are not pathognomonic. We have investigated the possible use of polymerase chain reaction (PCR) technology in reaching a definitive diagnosis of this lesion by its application to ten biopsy specimens with definitive diagnoses of OHL determined by in situ hybridization. EBV DNA was demonstrated by PCR in all ten OHL biopsy specimens analysed, and none of ten control specimens. Furthermore, we have investigated the role of PCR in analysis of exfoliative cytology samples collected from the lateral border of the tongue by a minimally-invasive scraping technique. EBV DNA was not only detected in all OHL lesional scrapings but also in more than one-third of healthy controls, due to viral presence in saliva at the time of sampling. In this application, the highly sensitive PCR technique has low specificity and cannot be recommended.

Adolescent↗
PubMed1994

Work-site cholesterol screening and dietary intervention: the Staff Healthy Heart Project. Steering Committee.

OBJECTIVES: The Staff Healthy Heart Project was established to run a work-site cholesterol screening project and a randomized controlled trial of dietary interventions. METHODS: Screening was offered to all staff at six Australian hospitals. Participants with blood cholesterol of 5.2 mmol/L (200 mg/dL) or above were randomly allocated to receive screening only (control group), a self-help package, or a nutrition course. Participants were seen 3 and 6 months after intervention to measure blood cholesterol and dietary changes. RESULTS: Eighty percent of available staff (n = 2638) were screened. Of those eligible, 67% (n = 683) entered the trial. Follow-up measures of blood cholesterol and dietary intake were obtained for 63% and 38% of trial participants, respectively. A reduction in reported dietary fat was found for all groups, but there were no significant differences between groups. Reported dietary fiber rose by 0.6 g/MJ/day for those in the nutrition course. There were no changes in total blood or high-density lipoprotein cholesterol. CONCLUSIONS: Cholesterol reduction was not demonstrated, but this result is difficult to interpret given the poor ongoing participation rates. Strategies to improve ongoing participation in work-site projects are needed to achieve adequate assessment of dietary interventions used in cholesterol screening.

Adolescent↗
PubMed1993

Oligonucleotide fingerprinting of isolates of Candida species other than C. albicans and of atypical Candida species from human immunodeficiency virus-positive and AIDS patients.

Oligonucleotide fingerprinting of genomic DNA from oral isolates of four different Candida species other than C. albicans and atypical chlamydospore-positive isolates from human immunodeficiency virus (HIV)-positive individuals and AIDS patients was investigated as a means for differentiating between isolates within individual species. Oligonucleotides composed of simple repetitive sequence motifs, including (GACA)4, (GATA)4, (GGAT)4, (GTG)5, and (GT)8, all yielded fingerprints suitable for strain segregation of 8 C. tropicalis isolates, 12 Torulopsis (Candida) glabrata isolates, 8 atypical Candida isolates, and, except for (GATA)4, 2 C. krusei probe in turn and so generate several distinct DNA fingerprints of the same DNA sample. However, none of the probes yielded fingerprints suitable for strain segregation with three C. parapsilosis isolates. The (GATA)4 probe was also used to detect restriction fragment length polymorphisms among a genetically closely related group of atypical Candida isolates on primary isolation from an additional HIV-infected patient. These chlamydospore-positive atypical Candida isolates were sucrose positive, were of C. albicans serotype A, hybridized weakly with the C. albicans-specific mid-repeat sequence probe 27A, and yielded fingerprint profiles by random polymorphic DNA analysis that were distinct from those derived from C. albicans isolates. The C. stellatoidea ex-type strain NCPF 3108 was indistinguishable from the atypical Candida isolates in all these tests and also yielded an identical carbohydrate and nitrogen source assimilation profile by using the ID 32C yeast identification system.

AIDS-Related Opportunistic Infections↗
PubMed1992

Novel spirosuccinimides with incorporated isoindolone and benzisothiazole 1,1-dioxide moieties as aldose reductase inhibitors and antihyperglycemic agents.

Compounds from two novel series of spirosuccinimides were prepared. Analogs of series 2 possessed a spiro-fused isoindolone moiety while those of series 3 contained a spiro-fused benzisothiazole S,S-dioxide group. These compounds were evaluated as aldose reductase inhibitors (ARI) in vitro by their ability to inhibit glyceraldehyde reduction using a partially purified bovine lens aldose reductase preparation and in vivo as inhibitors of galactitol accumulation in the lens, sciatic nerve, and diaphragm of galactose-fed rats. Many members from the isoindolone series 2, particularly those containing an isoindolone N-methyl moiety, showed good in vitro and in vivo potency. The most potent member, the 6-chloro analog 32, was resolved, and aldose reductase activity was found to reside almost exclusively in the (+)-enantiomer. Compound 32 was approximately equipotent in the sciatic nerve of the galactose-fed rat to other cyclic imide ARI's of similar in vitro activity, namely sorbinil and ADN-138 and also to tolrestat, an acetic acid-based ARI (ED50's 4-8 mg/kg). Compounds from both series, 2 and 3, were also found to lower plasma glucose levels of genetically obese db/db and ob/ob mice with potency similar to that of ciglitazone. However, members from these series failed to lower insulin levels of the ob/ob mouse at the doses tested.

Aldehyde Reductase↗
PubMed1992

Effect of thermal injury on transfer of IR22 IgA myeloma protein into bile in the rat.

We previously observed a 75-90% decrease in concentration of biliary IgA after thermal injury to rat skin. Decrease in biliary IgA might result from an alteration in supply of polymeric IgA delivered to the hepatocyte or from an alteration in hepatocyte transfer of polymeric IgA into bile. In the present study, we examined the transfer of intravenously administered 125I-IgA into bile. Purified IR22 rat IgA myeloma protein consisting of both monomeric and polymeric IgA was labelled with 125I. Sprague-Dawley rats (140-180 g) received a 20-30% body surface area scald-burn or sham treatment. The bile duct was cannulated 18-24 h later and 125I-IgA preparations were injected into the tail vein. Bile was collected under light ether anesthesia for 3 h. In rats injected with 125I-IR22 IgA myeloma protein there were no significant differences in total, TCA-precipitable, or immunoprecipitable radioactivity in bile from burn-injured or sham-treated animals. On Bio-Gel A-1.5 m gel permeation, the radioactivity in bile from sham-treated animals eluted in the region of polymeric IgA as expected; the radioactivity in the bile from burn-injured animals eluted equally in the same regions as polymeric IgA and monomeric IgA. In sham-treated rats injected with isolated polymeric IgA only, bile contained primarily polymeric IgA. In burn-injured rats injected with polymeric IgA only, bile contained a mixture of polymeric IgA and monomeric IgA. These findings suggest that hepatocyte processing of polymeric IgA is altered after thermal injury, resulting in the transformation of some polymeric IgA into its monomeric form.

Animals↗
PubMed1992

Hypercholesterolemia after chemotherapy for testis cancer.

PURPOSE: The study was designed to determine prospectively the prevalence of fasting serum lipid abnormalities in patients who were treated with cisplatin-based chemotherapy for germ cell tumors. We unexpectedly had demonstrated hypercholesterolemia in 20 of 30 nonfasting patients in a prior study of long-term toxicity of chemotherapy for germ cell tumors. The present study was designed to explore this phenomenon further. PATIENTS AND METHODS: Seventeen unselected patients with biopsy-proven germ cell tumors, who underwent cisplatin-based chemotherapy and who had no prior history of cardiac disease nor known hypercholesterolemia, were studied. In addition to the standard staging tests, blood was drawn for a pretreatment fasting lipid screen, which included cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, and apolipoproteins A1, B, and (a). Repeat samples were drawn 24 hours after the administration of cisplatin and at intervals of 6 to 24 months after the completion of treatment. RESULTS: Seven of 17 patients (41%) had higher than desirable levels of total serum cholesterol and low-density lipoprotein cholesterol. Two of them had normal levels before treatment, four had preexisting hypercholesterolemia that increased further, and one patient had an elevated pretreatment level that did not alter. Absolute increases in serum cholesterol were noted in 14 of 17 patients. No consistent patterns of change beyond the reference ranges were found for other serum lipids. CONCLUSIONS: We have confirmed our initial observation that serum cholesterol increases in patients who received cisplatin-containing chemotherapy regimens for germ cell tumors. Further studies will be necessary to define whether other lipid abnormalities occur and the biologic significance of these findings.

Adolescent↗
PubMed1991

The effect of danazol on pulsatile gonadotropin secretion in women with endometriosis.

OBJECTIVE: To determine whether the effect of danazol on gonadotropin pulsatility was due to a direct effect of the drug or the suppression in the estradiol (E2) levels. DESIGN: Prospective analysis of serial blood samples at 10-minute intervals for 5 hours on days 3, 4, or 5 of the control cycle and 2 months after the start of danazol treatment. SETTING: Tertiary institutional outpatient care. PATIENTS, PARTICIPANTS: Six eugonadal women with minimal endometriosis. INTERVENTIONS: Oral administration of danazol, 200 mg three times daily. MAIN OUTCOME MEASURES: Gonadotropin mean levels, pulse frequency, and amplitude. RESULTS: The mean level of E2 was the same in the control cycle as that during danazol treatment (170 pmol/L). Danazol administration resulted in a 16% increase in the mean luteinizing hormone (LH) pulse amplitude (95% confidence interval [CI] 6% to 26%, P less than 0.01), associated with a 20% decrease in LH pulse frequency (95% CI -71% to +31%, P = 0.37). There was a nonsignificant increase in follicle-stimulating hormone (FSH) pulse amplitude (2%, 95% CI -9% to +14%, P = 0.68) and in FSH pulse frequency (27%, 95% CI -4% to +58%, P = 0.08). The 22% decrease in the mean LH level (95% CI -85% to +12%, P = 0.13) and the 20% decrease in the mean FSH level (95% CI -53% to +37%, P = 0.33) were also not significant. CONCLUSIONS: The increase in LH pulse amplitude represents a direct effect of danazol on the hypothalamic-pituitary axis.

Adult↗
PubMed1991

Tumour evolution in rats monitored by changes to serum and lipoproteins.

The biochemical, physicochemical and magnetic resonance (MR) properties of rat serum allow tumour evolution to be monitored. Serum from female Fischer rats injected with rat mammary adenocarcinoma cells contained a low-density lipoprotein (LDL)-like lipoprotein and decreased high-density lipoprotein levels compared with normal rat serum. Increases in secondary tumour burden coincided with enlarged LDL-like particles, altered MR properties and elevation of serum triglyceride. By fucosidase treating metastatic R13762 cells prior to injection, not only was metastatic capacity retarded, but serum lipoproteins were also altered. These physicochemical alterations suggest an intricate relationship between both primary and secondary tumour burdens and the serum lipoprotein profile.

Adenocarcinoma↗
PubMed1990

Comparison of simvastatin and cholestyramine in the treatment of primary hypercholesterolaemia.

The effects of simvastatin, a competitive inhibitor of the enzyme 3-hydroxy-3-methylglutaryl-coenzyme A reductase, on plasma lipid levels were compared with those of the bile acid sequestrant cholestyramine in a randomized parallel study of 60 subjects with primary hypercholesterolaemia. After a 12-week direct comparison period 37 subjects with inadequate cholesterol reduction received a combination of both drugs and all subjects were followed for a further 40 weeks. Simvastatin was more effective than cholestyramine in lowering total and LDL cholesterol levels and the LDL/HDL ratio (-31.7% v. -19.7% [P less than 0.01], -41.0% v. -31.8% [P less than 0.05] and -46.7% v. -33.6% [P less than 0.01], respectively at Week 12). Only simvastatin significantly increased the HDL cholesterol concentration (+13.3% [P less than 0.01] v. +6.4%). Cholestyramine increased plasma triglyceride levels by 37.5% (P less than 0.01) whereas simvastatin caused a slight non-significant reduction. Combined therapy produced a further decrease in total and LDL cholesterol levels, and in the LDL/HDL ratio, which was sustained for the duration of the study. Simvastatin was better tolerated than cholestyramine (P less than 0.01), and combining the two drugs enhanced efficacy without increasing the frequency of side effects.

Adult↗
PubMed1990

Assay of apolipoproteins A-1 and B by immunoturbidimetry: detection of individuals at risk for atherosclerotic artery disease.

Recent evidence has suggested that the levels of Apolipoprotein A-1 and B in plasma are better indicators of the risk of atherosclerotic artery disease than plasma lipids. This study describes the measurement of plasma Apolipoprotein A-1 and B by immunoturbidimetry in patients with atherosclerotic artery disease and in normal controls. Apoprotein B and the ratio of Apoprotein A-1/Apoprotein B were found to be the best discriminators between the two groups.

Adult↗