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Biomedical subjects

W Thomas

Publications and source records attributed to W Thomas.

At least 91 records · Page 5Linked to original sources
PubMed1995

Are specific serum insulin levels low in impaired glucose tolerance and type II diabetes?: measurement with a radioimmunoassay blind to proinsulin, in the population of Wadena, Minnesota.

It has been suggested that serum insulin levels in subjects with recently diagnosed type II diabetes have been overestimated, and that after correction for proinsulin, true insulin levels are depressed rather than elevated. We tested this possibility in a cross-sectional study of a population-based sample of 328 adults living in Wadena, a Minnesota community in which residents are of northern European background. Specificity of insulin measurements was provided by an antibody blind to proinsulin and its major metabolite. Oral glucose tolerance and liquid mixed-meal (Ensure-Plus) tests were performed on separate days. Mean insulin levels before and 90 minutes after the mixed meal were as follows. Among 302 randomly ascertained adults not previously known to have diabetes, both fasting and postmeal levels in subjects with impaired glucose tolerance (IGT) and newly identified type II diabetes were equal to or greater than levels in subjects with normal glucose tolerance (fasting: normal 52 pmol/L, IGT 78, new type II 87; postmeal: 317, 565, and 406, respectively). The fasting insulin to glucose ratio was significantly increased in IGT and new type II diabetes subjects. Among 26 established (previously known) type II diabetic subjects not taking insulin, fasting levels were elevated and postmeal levels were normal in absolute terms (75 and 328), but were normal or low with respect to plasma glucose. Relationships among the groups were not materially changed by adjustment for body mass index (BMI), sex, age, or blood pressure. There was marked overlap of individual insulin levels from group to group. In summary, randomly selected adults in Wadena with IGT or asymptomatic diabetes showed, on average, elevated insulin levels, but physician-diagnosed diabetes was associated with relative diminution of serum insulin. In this population, the current view of insulin resistance in "early" diabetes was supported by insulin-specific measurements.

Adult↗
PubMed1995

Expression of the SmpA outer membrane lipoprotein of Serpulina hyodysenteriae strain P18A in vivo.

An ELISA has been developed using a monoclonal antibody (F325 AC4) to the SmpA surface lipoprotein of Serpulina hyodysenteriae strain P18A when grown in vitro. The lower level of detection of the ELISA was approximately 5 x 10(6) spirochaetes/ml when spirochaetes were either resuspended in phosphate buffered saline or in pig faeces. When pigs were challenged with S. hyodysenteriae strain P18A the lipoprotein was detected in the faeces of pigs by ELISA when the numbers of spirochaetes excreted was greater than 10(6) per g of faeces. After onset of clinical signs in the pig, expression of SmpA was not detected by ELISA or by Western blotting using either monoclonal antibody F325 AC4 or polyclonal antiserum B50 against the SmpA antigen. However, when the in vivo grown spirochaetes were subsequently cultured in vitro expression of SmpA was detected by Western blotting. In the mouse model of swine dysentery S. hyodysenteriae spirochaetes obtained from mice with gross lesions also did not express SmpA. It was concluded that the apparent lack of expression may have been the result of environmental regulation of gene expression or antigenic variation and was not due to denaturation of the antigen in vivo.

Animals↗
PubMed1995

Central neurocytoma. A clinicopathological, immunohistochemical and ultrastructural study of 7 cases.

Characterised by distinctive clinicopathological features, the central neurocytoma (CN) is an uncommon and possibly under-recognised primary cerebral neuronal neoplasm. We present clinical and pathological details of seven patients with CN. Histological examination revealed a greater diversity of morphological appearances than is typically described in CN. No anaplastic features were identified. Cellular areas resembling both oligodendroglioma and ependymoma were present in all cases, but each tumour also contained stroma rich areas with hyalinised or aneurysmal vessels. Synaptophysin was expressed by all tumours and probably represents the immunohistochemical marker of choice for identifying CN. Distinguishing ultrastructural features included rounded cell bodies separated by numerous cell processes containing microtubules, pleomorphic neurosecretory granules and occasional synapses. Ki-67 immunostaining revealed a low cell proliferation index in each case. The distinction of CN from other pathological mimics can be reliably made using this multiparametric approach to diagnosis. The generally benign behaviour of CN is confirmed, though there was one patient death in the follow-up period of 10-122 months. Aggressive behaviour in this case was not associated with anaplastic histological features.

Adult↗
PubMed1995

The effect of nimodipine on essential tremor.

We investigated the effect of nimodipine (30 mg qid) in 16 de novo patients with essential tremor in a double-blind placebo-controlled study in which we assessed tremor by clinical scorings, tremorgraphic recordings, and patient self-evaluation. Of the 15 patients who completed the study, eight improved. We conclude that nimodipine is effective in some patients with essential tremor.

Adult↗
PubMed1994

Allogeneic bone marrow transplantation for acute lymphoblastic leukaemia: risk factors and clinical outcome.

We report 12 years' experience with histocompatible, related donor marrow transplantation for 123 patients with acute lymphoblastic leukaemia; 104 > or = second remission. Four regimens were studied: cyclophosphamide (Cy)-+total body irradiation (TBI) (n = 35); Cy+fractionated TBI (n = 45); TBI+high-dose cytarabine (n = 15); and hyperfractionated TBI+Cy (n = 28). 45 patients survive (34 +/- 9%; 95% confidence interval) between 1 and 12.7 years (median 7.8 years) following BMT and 29 +/- 8% survive leukaemia-free. Significantly improved disease-free survival was observed in patients with an initial WBC < 50 x 10(9)/l (P = 0.02). Conditioning regimens tested yielded similar outcomes, though TBI/cytarabine led to greater treatment-associated mortality. Leukaemia relapse was the most frequent cause of failure in 56 +/- 11%; median time of relapse 8 months following BMT, none beyond 2.2 years. Relapse was more frequent with higher WBC, shorter initial remission and previous CNS leukaemia. Acute and/or chronic GVHD was associated with a strong trend (P = 0.06) towards less relapse. Allogeneic BMT may be curative for a substantial fraction of patients with ALL, but additional anti-leukaemic measures beyond these conditioning modifications tested will be required to prevent post-transplant leukaemia recurrence.

Adolescent↗
PubMed1994

[Significance of the position of the endoprosthesis acetabular cup from the biomechanical and clinical viewpoint--recommendations for a classification].

The success of an artificial joint replacement over the long term depends, for the most part, on the optimal positioning of the acetabular cup. We investigated this thought in terms of biomechanical and clinical considerations, and, on the basis of a proposed classification, attempted to ascertain the best possible position. On the basis of our analysis we determined that the ideal position is an angle of 35 degrees, with a tolerance range of 25 degrees to 45 degrees. Here, the load on the polyethylene is low, so that wear and the formation of particles are minimized. This position can readily be achieved surgically with the aid of an auxiliary device and clinically provides the best results in terms of muscular stability, endurance and optimal scoring.

Acetabulum↗
PubMed1993

A genetic analysis of the Werner syndrome region on human chromosome 8p.

Werner syndrome (WRN) is an inherited disorder that produces symptoms of premature aging. This disease is caused by a recessive mutation that has previously been mapped to chromosome 8p. We have now used genetic linkage analysis to map the WRN gene relative to chromosome 8 reference loci, to screen candidate genes, and to identify a novel dinucleotide repeat polymorphic marker closely linked to WRN. The WRN locus was mapped relative to the marker loci, PLAT, ANK1, D8S135, and D8S87 of the comprehensive chromosome 8 linkage map. The heregulin (HRG) and the fibroblast growth factor receptor 1 genes (FGFR1) have been mapped to chromosome 8p and are involved in cellular growth. Recombination events were detected between WRN and the HRG and FGFR1 genes, excluding them as candidates for the WRN gene. A polymorphic marker generated in this study, WT251, is linked to WRN at a recombination fraction of 0.006, with a lod score of 16.5.

Base Sequence↗
PubMed1993

Comparison of a needleless system with conventional heparin locks.

BACKGROUND: Despite the improvements in needle disposal systems, needlesticks to health care workers continue to occur at unacceptably high rates. Needleless systems have been shown to reduce the risk of needlesticks. METHODS: This pilot study examined the safety of such a system for patients by comparing the rates of intravenous infection-related indicators between a conventional heparin lock and a needleless system. Patients (n = 97) were categorized on the basis of the duration of intravenous placement into 24-, 48-, and 72-hour groups. Within each group, half of the patients received conventional heparin locks and half received the needleless system. Intravenous infection-related indicators included catheter tip culture, adaptor fluid culture, intravenous site erythema, induration and tenderness, and elevated oral temperature. RESULTS: Prevalence of one or more indicators was 48% for the conventional and 40% for the needleless system, a difference that was not statistically significant. CONCLUSIONS: The needleless system appeared to pose no greater risk of infection to patients and nurses preferred it for its reduced risk of potential needlesticks.

Accidents, Occupational↗
PubMed1993

Screening diabetic transplant candidates for coronary artery disease: identification of a low risk subgroup.

Coronary artery disease is the major cause of death in diabetic renal transplant recipients. Because one-third of diabetic transplant candidates have clinically silent coronary artery disease, many transplant centers recommend coronary angiography prior to transplantation. However, angiography is expensive and may precipitate acute renal failure. Therefore, we developed a noninvasive screening algorithm to identify patients at low risk for coronary artery disease (CAD), defined as one or more coronary stenoses > or = 50% diameter. We performed coronary angiography in 141 consecutive asymptomatic Caucasian type I diabetic renal transplant candidates. Fourteen of 16 patients age 45 or older had CAD. One hundred and twenty-five patients under age 45 were randomly divided into two groups. Ninety patients were used to identify clinical factors significantly associated with CAD which included smoking for five or more pack years, nonspecific ST-T wave changes on electrocardiogram, and diabetes duration 25 years or longer. The screening algorithm, "CAD is predicted in diabetic transplant candidates under age 45 with any of the above risk factors," was then tested in the remaining 35 patients and in 35 additional patients. In these 70 patients, the algorithm had a sensitivity of 97% and a negative predictive accuracy of 96%. We conclude that coronary angiography should be recommended to Caucasian type I diabetic renal transplant candidates age 45 or older because of the high probability of disease. In patients younger than 45 without a smoking history, ST-T wave changes on EKG, or diabetes longer than 25 years, the likelihood of CAD is low and angiography can be avoided.

Adult↗
PubMed1993

Cytomegalovirus pneumonia after bone marrow transplantation. Risk factors and response to therapy.

Cytomegalovirus pneumonia complicated bone marrow transplantation in 75 (63 allogeneic and 12 autologous) of 1136 recipients (Kaplan-Meier incidence 8.8%). CMV pneumonia occurred more frequently in allogeneic (12.4%) than autologous recipients (3.3%). Increased risk for CMV pneumonia was observed in allogeneic recipients who were seropositive (relative risk = 2.9), older age (RR = 1.4 per decade), those conditioned with total-body irradiation (RR = 2.7), who received antithymocyte globulin (RR = 2.9) or T cell-depleted marrow (RR = 2.7) or who had CMV viruria (RR = 4.0) or viremia (RR = 5.9). Autologous recipients were also at increased risk if they were seropositive (RR = 6.1), or developed viruria (RR = 7.0) or viremia (RR = 15.4). Thirteen of 14 untreated patients died without improvement. Prognosis was poor in patients who were ventilator-dependent at initiation of therapy (median survival 17 days), with only 1 long-term survivor. In contrast, patients ventilator-independent at initiation of therapy with ganciclovir and immunoglobulin (n = 22) had a median survival of > 274 days, with 9 long-term survivors. Ganciclovir alone or acyclovir with immunoglobulin in ventilator-independent patients was less effective (median survivals 80 and 10 days, respectively). Overall, 10 of 75 patients were surviving 10-73 months (median 47) from diagnosis; 9 of these were ventilator-independent at initiation of therapy and received ganciclovir with immunoglobulin. CMV pneumonia was less common, but was severe in autologous recipients, with only 2 of 12 surviving. CMV pneumonia remains a prominent cause of death following BMT. Early therapy with ganciclovir and immunoglobulin before respiratory failure supervenes may improve survival.

Acyclovir↗
PubMed1993

Molecular cloning, expression, and DNA sequence analysis of the gene that encodes the 16-kilodalton outer membrane lipoprotein of Serpulina hyodysenteriae.

The gene (smpA) that encodes the 16-kDa outer membrane lipoprotein of Serpulina hyodysenteriae was cloned in Escherichia coli, and its primary structure was determined by nucleotide sequencing. The putative open reading frame encodes a prolipoprotein of 16.8 kDa which in its fully acylated and cleaved form is 15.1 kDa. Analysis of the N-terminal amino acid sequence derived from the DNA sequence revealed the presence of a signal sequence and a putative acylation and signal peptidase II cleavage site (Phe-Ala-Val-Ser-Cys). In E. coli, processing of the prolipoprotein was less efficient than that observed in S. hyodysenteriae, and globomycin, an inhibitor of signal peptidase II, inhibited cleavage of the lipoprotein expressed in E. coli but did not inhibit cleavage in S. hyodysenteriae.

Amino Acid Sequence↗
PubMed1993

Metabolic effects of dietary sucrose in type II diabetic subjects.

OBJECTIVE: To assess in diabetic subjects the effects of dietary sucrose on glycemia and lipemia. RESEARCH DESIGN AND METHODS: Twelve type II diabetic subjects consumed, in random order, two isocaloric, 55% carbohydrate study diets for 28 days. In one diet, 19% of energy was derived from sucrose. In the other diet, < 3% of energy was derived from sucrose, and carbohydrate energy came primarily from starch. Both study diets were composed of common foods. All meals were prepared in a metabolic kitchen where foods were weighed during meal preparation. RESULTS: No significant differences were noted between the study diets at any time point in mean plasma glucose. At day 28, mean plasma glucose values for the sucrose diet were 9.6 +/- 0.5 mM and for the starch diet were 9.4 +/- 0.6 mM (P = 0.63). Also, no significant differences were observed between the study diets in urine glucose, fasting serum total, HDL, or LDL cholesterol; fasting serum TG; or peak postprandial serum TG. CONCLUSIONS: A high sucrose diet did not adversely affect glycemia or lipemia in type II diabetic subjects.

Adult↗
PubMed1993

Acute lymphoid leukemia associated with Maffucci's syndrome.

PURPOSE: Maffucci's syndrome is a nonhereditary congenital disorder associated with multiple enchondromas, soft tissue hemangiomas, or lymphangiomas. It carries an associated high risk of the development of malignant neoplasms, particularly sarcomatous transformation of an enchondroma, as well as other malignant mesodermal and nonmesodermal neoplasms. Hematopoietic malignancies arising in Maffucci's syndrome are exceedingly rare. We report the case of a 14-year-old girl with Maffucci's syndrome who developed acute lymphoid leukemia. PATIENTS AND METHODS: The patient presented at 18 months of age with enchondromatosis. Maffucci's syndrome was established at 10 years of age after the appearance of multiple hemangiomas. RESULTS: At 14 years of age the patient developed fatigue, frequent nosebleeds, easy bruising, and weight loss, with circulating blasts in the peripheral blood. Bone marrow examination showed replacement of marrow spaces with leukemic blasts. Immunohistochemical and flow cytometric findings were consistent with a diagnosis of acute lymphoblastic leukemia with myeloid antigen expression. CONCLUSIONS: The occurrence of acute leukemia in a patient with Maffucci's syndrome may represent predisposition to yet another malignancy and reflect further expression of a generalized mesodermal dysplasia in these patients. It also emphasizes the need for aggressive surveillance in patients with Maffucci's syndrome.

Adolescent↗
PubMed1993

Cigarette smoking among women in Oklahoma: before, during, and after pregnancy.

Data from the Oklahoma Pregnancy Risk Assessment Monitoring System (PRAMS) were assessed to determine the prevalence of maternal cigarette smoking and its relationship to pregnancy outcomes. A mail and telephone questionnaire was used to survey mothers between four and six months postpartum to obtain information about smoking and other maternal behaviors. Monthly samples were drawn from the state's live birth registry utilizing a systematic stratified sampling approach based on infant birth weight. A total of 3,051 responses were received between 1988 and 1990 for an overall return rate of 70%. Results of the study show approximately one-third (32%) of women in Oklahoma smoked 3 months prior to pregnancy, 22% smoked in their last 3 months of pregnancy, and 29% smoked shortly after delivery. Women who smoked during pregnancy were 2.2 times more likely to deliver a low birth weight (LBW) infant than nonsmokers, and 1.4 times more likely to have gained less than the recommended amount of weight. Additionally, women who smoked during pregnancy were 1.4 times more likely to begin prenatal care in the second or third trimester, or to receive no care at all. In conclusion, maternal smoking cessation has the potential for dramatically reducing preventable adverse outcomes of pregnancy.

Birth Weight↗