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Biomedical subjects

W Thomas

Publications and source records attributed to W Thomas.

At least 19 recordsLinked to original sources
PubMed1992

Detection and quantitation of malignant cells in the peripheral blood of multiple myeloma patients.

One of the distinguishing features of multiple myeloma (MM) is the proliferation of plasma cells that home to the bone marrow (BM). However, there still remains some uncertainty concerning the presence of related malignant cells in the peripheral blood of myeloma patients. Using consensus oligonucleotide primers, we amplified the third complementary determining region (CDR3) of rearranged immunoglobulin heavy chain alleles from MM marrow samples by polymerase chain reaction (PCR). From the sequences of the products, we derived allele-specific oligonucleotides (ASO), and these were used in subsequent amplification reactions to detect malignant clones in the peripheral blood of myeloma patients. This method is highly specific and sensitive to 1 malignant cell in the background of 10(5) normal cells. Using this method we detected circulating malignant cells in 13 of 14 previously untreated MM patients. Furthermore, by applying ASO-PCR to artificial titrations of initial BM DNA sample into normal peripheral blood lymphocyte (PBL) DNA we were able to generate standard curves and quantitate the amount of tumor in the patient PBL. We observed a wide variation in the amount of circulating tumor between patients. In addition, we found that the incidence of circulating tumor cells was independent of BM tumor burden and stage of disease. The detection and quantitation of circulating tumor cells in the PBL of MM patients may offer an alternative assessment of the disease and may be an important consideration in the use of peripheral stem cells in bone marrow transplantation.

Base Sequence↗
PubMed1992

Metabolic effects of dietary fructose in healthy subjects.

To determine if dietary fructose causes adverse metabolic effects, we used a crossover design to compare a diet containing 20% of energy from fructose with an isoenergic high-starch diet that contained less than 3% fructose. Fourteen healthy subjects consumed each diet for 28 d. There were no significant differences between the diets in the mean values of hemoglobin A1C, serum glycosylated albumin, fasting plasma glucose, peak postprandial plasma glucose, integrated plasma glucose, fasting serum lactate, or fasting serum triglycerides. Peak postprandial serum lactate was significantly higher during the fructose diet at days 1, 7, and 14 but not at days 21 or 28. Peak postprandial serum triglycerides were significantly higher only at day 1 of the fructose diet. Day-28 fasting serum total and LDL cholesterol for the fructose diet were 9.0% and 11.0% higher, respectively, than the corresponding values for the starch diet. A high-fructose diet compared with a high-starch diet resulted in significantly higher fasting serum total and LDL cholesterol and also caused transient changes in postprandial serum lactate and triglycerides.

Adult↗
PubMed1992

Monoclonal antibodies to a 16-kDa antigen of Serpulina (Treponema) hyodysenteriae.

Monoclonal antibodies (MAbs) were produced to an outer-envelope preparation from Serpulina (Treponema) hyodysenteriae, the aetiological agent of swine dysentery. Three MAbs (isotype IgG1) were obtained. All three recognised a 16-kDa antigen that was common to most strains of S. hyodysenteriae of different serotypes but was absent from nonpathogenic, porcine intestinal spirochaetes. Immunofluorescence and immunogold labelling studies showed that the 16-kDa antigen was exposed on the surface of intact spirochaetes. The MAbs agglutinated freshly grown cultures of spirochaetes and inhibited growth of S. hyodysenteriae strains in vitro.

Agglutination Tests↗
PubMed1992

Nutritional behaviour and quality of life during oncological polychemotherapy: results of a prospective study on the efficacy of oral nutrition therapy in patients with acute leukaemia.

A total of 29 patients with acute leukaemia were prospectively randomized before starting cytostatic treatment to be nourished either with intensified oral nutrition (intervention group) or ad libitum nutritional intake during the whole tumour therapy (median 22 weeks). All received menus of free choice (daily offer of 1.0-2.0 g protein, 30-50 kcal kg-1 body weight (BW)). Beyond this, intervention patients received nutrition education, daily visits by the dietician and record of food intake, as well as a weekly assessment of subjective well-being (linear analogue self assessment 'LASA'). From the LASA items, the factors: 'malaise', 'psychological distress', 'therapy side-effects' were extracted by principal component analysis, and correlated to nutrient intake and nutritional status. At the end of antineoplastic induction therapy, after continuous hospitalization of 10 weeks (median), 31.3% of the controls had regained their initial nutritional status, and 68.8% of the intervention group. Mean daily energy intake was 23.2 kcal kg-1 BW during weeks with weight loss (constant weight: 30.9, weight gain: 39.3 kcal kg-1 BW). Nutritional behaviour correlated with subjective well-being, low intake with complaints of tumour treatment side effects and weight loss with malaise.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1992

The synthesis and function of the Escherichia coli hemolysin and related RTX exotoxins.

The RTX group of exotoxins represents a branch of a family of exoproteins produced by Gram-negative bacteria which share the properties of being secreted by a leader-independent pathway and a tandemly-repeated nine-amino-acid sequence that is responsible for calcium binding. The Escherichia coli hemolysin (HlyA) is the prototype for the RTX exotoxin family which includes the leukotoxins of Pasteurella haemolytica and Actinobacillus actinomycetemcomitans and hemolysins from four Gram-negative genera. A review of the genetics, synthesis, export and target cell reactivity of the E. coli hemolysin is given. An evolutionary tree of the RTX toxin family based on amino acid sequence similarity is presented.

Animals↗
PubMed1992

A 16-kilodalton lipoprotein of the outer membrane of Serpulina (Treponema) hyodysenteriae.

Serpulina (Treponema) hyodysenteriae P18A and VS1 were extracted by using the detergent Triton X-114 and separated into detergent and aqueous phases. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western immunoblot analysis confirmed that a membrane-associated 16-kDa antigen was hydrophobic, since it was found in the detergent phase. A 45-kDa antigen partitioned into the aqueous phase, suggesting that it was hydrophilic and may be of periplasmic origin. When spirochetes were grown in the presence of [3H]palmitic acid, a predominant 16-kDa antigen was labeled; from the results of immunoprecipitation experiments, this antigen appeared to be the same as that recognized by both polyclonal and monoclonal antisera to a previously described 16-kDa antigen. This antigen was proteinase K sensitive and was not a component of the lipopolysaccharide, which, although [3H]palmitate labeled, was resistant to proteinase K digestion. The most probable explanation is that the 16-kDa antigen is a membrane-associated, surface-exposed, immunodominant lipoprotein.

Animals↗
PubMed1992

Metabolic effects of dietary fructose in diabetic subjects.

OBJECTIVE: To assess the metabolic effects of chronic dietary fructose consumption in diabetic subjects. RESEARCH DESIGN AND METHODS: Six type I and 12 type II diabetic subjects consumed, in random order, two isocaloric study diets for 28 days. In one diet, 20% of energy was derived from fructose. In the other diet, < 3% of energy came from fructose, and carbohydrate energy was derived primarily from starch. Both study diets were composed of common foods. All meals were prepared in a metabolic kitchen where all foods were weighed during meal preparation. RESULTS: Mean plasma glucose, urine glucose, and serum glycosylated albumin values were lower during the fructose diet than during the starch diet, but the differences achieved only marginal statistical significance. The day-28 value for mean plasma glucose was 12.5% lower (P = 0.03) during the fructose diet than during the starch diet. At days 14, 21, and 28, fasting serum cholesterol and LDL cholesterol were both significantly higher during the fructose diet than during the starch diet. The day-28 values for serum cholesterol and LDL cholesterol during the fructose diet were 6.9% (P = 0.008) and 10.9% (P = 0.002) higher, respectively, than the corresponding values during the starch diet. No differences were observed between the study diets in fasting serum HDL cholesterol, fasting serum triglycerides, peak postprandial serum triglycerides, or fasting serum lactate. Peak postprandial serum lactate was significantly higher during the fructose diet. Type I and type II diabetic subjects responded to the diets in a consistent way, but type I subjects experienced significantly more hypoglycemia during the fructose diet than during the starch diet. CONCLUSIONS: A high-fructose diet may result in reduced glycemia in diabetic subjects but at the expense of increased fasting serum total and LDL cholesterol.

Adult↗
PubMed1992

Prevalence of, and risk factors for, angiographically determined coronary artery disease in type I-diabetic patients with nephropathy.

BACKGROUND--Thirty-five percent of type I-diabetic patients are dead of coronary artery disease by age 55 years, and the risk of death is increased eightfold to 15-fold in patients with nephropathy. However, the prevalence of coronary artery disease with respect to age is unknown and few risk factors have been identified. METHODS--One hundred ten insulin-dependent diabetic patients underwent routine pretransplant coronary angiography and cardiac risk factor assessment. Angiograms were evaluated by two angiographers for presence or absence of coronary artery disease (CAD, defined as one or more coronary artery stenoses of 50% or greater in diameter, and no CAD, defined as no stenosis of 25% or greater in diameter, respectively). Prevalence of CAD by age was determined, and associated risk factors were defined. RESULTS--Fifty-two of 110 patients had CAD. Coronary artery disease prevalence increased significantly with age; 13 of 16 patients older than 45 years of age had CAD. For patients 35 years of age or younger, associated risk factors included a family history of premature myocardial infarction, higher hemoglobin A1c level, hypertension for more than 5 years, lower high-density lipoprotein level, and smoking for more than 5 pack-years. For patients between 35 and 45 years of age, associated risk factors included number of years of diabetes, higher hemoglobin A1c levels, and smoking more than 5 pack-years. CONCLUSIONS--In type I-diabetic patients with nephropathy, CAD prevalence increased significantly with age and was found in the majority of patients older than 45 years of age. Coronary artery disease risk factors operative in the general population were significantly associated with CAD in this high-risk group. In addition, a role for hyperglycemia in accelerated atherogenesis was supported by the association of both higher hemoglobin A1c levels and number of years of diabetes with CAD.

Adult↗
PubMed1992

Fever in pheochromocytoma.

BACKGROUND: Fever is an infrequently reported finding in patients with pheochromocytoma. Fever in patients with pheochromocytoma may be caused by the tumor, an infection or other factors, each of which will dictate different treatment strategies. METHODS: To determine the incidence, cause, and significance of fever in patients with pheochromocytoma, we reviewed the medical records of 50 hospitalizations of 48 patients. Patients were categorized by the presence or absence of fever. Body temperature elevation, duration of hospitalization in the period prior to surgery or death, age, sex, race, other conditions that could have been responsible for the febrile episode (comorbid events), location, gross and microscopic features of the tumors, and plasma and urine hormone levels were tabulated. The results were compared between the two groups of patients. RESULTS: Fever was present in 14 (28%) of 50 hospitalizations, seven patients (50%) of whom had pheochromocytoma multisystem crisis. Patients with fever and pheochromocytoma were significantly more likely to have a comorbid event, larger tumor, necrosis within the tumor, higher urinary metanephrine levels, longer duration of hospitalization prior to surgery, and to be non-white. Comorbid events included both infectious and noninfectious potential causes of fever. CONCLUSIONS: Fever is common in patients with pheochromocytoma. The causes may be multifactorial and often include an associated illness. A thorough search for coexisting disease is indicated. While fever may prolong hospitalization, it does not portend a disastrous outcome.

Adrenal Gland Neoplasms↗
PubMed1991

Medical evaluation of internationally adopted children.

BACKGROUND: Despite many reports of medical illness in children adopted from abroad, there are currently no accepted guidelines for medical evaluation of this population. METHODS: Two hundred ninety-three children adopted from 15 countries (mean age, 14.0 months; 55 percent girls) were evaluated by history taking, physical examination, and screening tests for hepatitis B virus (HBV), human immunodeficiency virus type 1, tuberculin reactivity, intestinal parasites, syphilis, excretion of cytomegalovirus, renal disease, and anemia. All but four were seen within one month of their arrival in the United States. RESULTS: Fifty-seven percent of the children (168 of 293) were found to have at least one important medical condition. Eighty-one percent of the diagnoses were established by screening test, rather than by history taking or physical examination. Infectious diseases made up the majority of the medical conditions (73 percent). Serologic testing for hepatitis B surface antigen was positive in 5 percent of the children. Characteristics associated with the acquisition of HBV infection included arrival within the first three years of the study (P = 0.017), Asian origin (P = 0.011), and receipt of a blood transfusion abroad (P = 0.008). Ten children (3 percent) had positive Mantoux skin tests, and four of these had active pulmonary tuberculosis. Tuberculin reactivity was significantly associated with older age (P less than 0.001) and lower weight (P = 0.037). Intestinal parasites were isolated from 14 percent of the international adoptees. Non-Korean adoptees were 16 times more likely to be harboring at least one intestinal parasite than were Korean adoptees (P = 0.005). CONCLUSIONS: Directed screening tests should be a routine component of the medical evaluation of all children adopted from abroad, regardless of age, sex, or country of origin.

Adoption↗
PubMed1991

Aflatoxicosis alters avian renal function, calcium, and vitamin D metabolism.

Experiments were designed to determine the effects of aflatoxicosis on avian renal function, calcium (CA), inorganic phosphorous (Pi), and vitamin D metabolism, and to determine if the effects of aflatoxin are reversible upon discontinuation of toxin administration. Three-week-old male broiler chickens (n = 12 per treatment) received aflatoxin (AF; 2 mg/kg po) or an equal volume of corn oil, the AF carrier vehicle, for 10 consecutive days. After 10 d of treatment, half of the birds from each treatment group were anesthetized and prepared for renal function analysis, which included a 2-h phosphate loading period. Ten days after discontinuation of AF treatment, the remaining birds in each treatment group were anesthetized and prepared for renal function analysis. AF decreased plasma 25-hydroxy vitamin D [25(OH)D] and 1,25-dihydroxy vitamin D [1,25(OH)2D] levels after 5 d of treatment. After 10 d of treatment, urine flow rate (V), fractional sodium excretion (FENa), and fractional potassium excretion (FEK) were lower in AF-treated birds. In addition, total plasma Ca tended to be lower (p = .10) and fractional Ca excretion (FECa) tended to be higher (p = .10) in the AF-treated birds. Intravenous phosphate loading produced a sharp increase in urine hydrogen ion concentration ([H+]) in the AF-treated birds. Glomerular filtration rate (GFR) was reduced and plasma osmolality was increased in AF-treated birds 10 d after discontinuation of toxin administration. The results indicate that AF directly or indirectly affects Ca and Pi metabolism in avians. At the present time, the effects may be related to altered vitamin D and parathyroid hormone (PTH) metabolism. Aflatoxicosis may decrease endogenous PTH synthesis and the renal sensitivity to PTH. The AF-related increase in urine [H+] during phosphate loading is probably due to increased Na+/H+ counterport, suggesting that AF stimulates sodium reabsorption. Also, the decrease in GFR exhibited 10 d after toxin removal indicates that AF may cause prolonged alteration in renal function.

Aflatoxins↗
PubMed1991

Genetic analysis of the gyrase A-like domain of DNA topoisomerase II of Saccharomyces cerevisiae.

We have undertaken a genetic analysis of heat-sensitive and cold-sensitive mutations in TOP2, the gene encoding yeast DNA topoisomerase II. Deletion mapping was used to localize 14 heat-sensitive and four cold-sensitive top2 mutations created by a method biased toward mutations in the 3' two-thirds of the gene. The mutations all appear to be located in the region of DNA topoisomerase II that shows homology to the "A" subunit of bacterial DNA gyrase. The heat-sensitive mutations and one cold-sensitive mutation lie in the center of the gene near the sequence that encodes the active site tyrosine. The three other cold-sensitive mutations map farther toward the 3' end of the gene. The cold-sensitive mutations exhibit intragenic complementation, and the complementation groups correspond to the physical map. We sequenced nine top2 mutations and found that the mutations are usually single missense mutations, frequently involve proline, and affect conserved regions of the protein. Suppressor analysis yielded two intragenic suppressors and seven independent isolates of an allele-specific extragenic suppressor we named tos1; tos1 is not allelic to any genes predicted to encode type I topoisomerase-related proteins. The two intragenic suppressors were tested for allele-specificity; the results revealed a complex pattern of suppression between heat-sensitive and cold-sensitive top2 alleles. These top2 mutations may have compensatory effects on the general stability of the protein.

Base Sequence↗
PubMed1990

Segregation of recombined chromosomes in meiosis I requires DNA topoisomerase II.

To understand better the similarities and differences between meiosis and mitosis, we examined the meiotic role of DNA topoisomerase II, an enzyme that is required mitotically to disentangle sister chromatids at the time of chromosome segregation. In meiosis, we found that topoisomerase II is required only at the time of nuclear division. When cold-sensitive top2 mutants are induced to sporulate at the restrictive temperature, they undergo premeiotic DNA synthesis and commitment to meiotic levels of recombination but fail to complete the first meiotic nuclear division. The introduction of a mutation blocking recombination relieves the requirement for topoisomerase II in meiosis I. These results suggest that topoisomerase II is required at the time of chromosome segregation in meiosis I for the resolution of recombined chromosomes.

Cell Nucleus↗
PubMed1990

[Effect of diabetes-psychosomatic group education on metabolic control and coping with disease by insulin-dependent diabetic patients].

Even though cognitive education programs are essential for the treatment of diabetics, long term efficacy often seems to be poor. Problems of coping with illness could be the reason for a lack of transfer of knowledge into daily practice. Small discussion groups with the aim of modifying attitudes towards illness might be a good possibility to face this problem. 54 IDDM, HbA1 10.7 +/- 2.3% (median +/- SD) absolved our 5-day education program for outpatients, in which daily group sessions (90 min), supervised by a group-therapist, were integrated. Follow-up sessions took place after 1, 4 and 8 months. The efficacy was measured by HbA1 and different questionnaires on diabetologic knowledge, life satisfaction (FLZ) and complaints (BL). 4 months after the education program HbA1 had decreased to 9.0 (median +/- SD) and remained stable within small range during the rest of the study-period. Diabetologic knowledge increased from 70% (median +/- SD) to 87% (median +/- SD) 1 month after the education and remained stable during the rest of the study-period. Complaints decreased within one month from a level above average somatic illness to the normal level for healthy subjects. However, in regard to their life satisfaction our patients were significantly less satisfied concerning their health, whereas family life and friendship were declared to be more satisfying (after 8 months). We believe that more intensive communication in the family (encouraged by the group-therapy) and parallel more critical attitudes towards illness lead to this results. As basic elements for long term modification of illness behaviour these emotional aspects seem to be essential.

Adult↗
PubMed1990

Ventral interbody spondylodesis using a new plug-shaped implant.

A new technique for interbody lumbar spondylodesis using a new cancellous metal, plug-shaped construct was performed in 35 cases with spondylolisthesis or lumbar instability. All of these patients have had severe low-back pain for years, some with radicular symptoms and had been treated unsuccessfully for years. In a follow-up study, 28 of these patients were examined after a time-period of 4 to 24 months. According to objective criteria, the clinical results were good in 19 cases, moderate in five cases and poor in one case. The patients' own judgement about the success of the operation was somewhat different: 17 patients judged their condition as good, six as moderate and two as poor. For three patients the follow-up examination was so close to surgery that no judgement can be made. We saw postoperative complications in two cases: one was a fracture of the implant, the other was a deep vein thrombosis. Since the first reports about ventral spondylodesis by CAPENER [4] and BURNS [2] in the years 1932 and 1933 this surgical technique has been under discussion worldwide. This discussion even increased after HORMON [10] published some reports about his experience with this operative treatment in 1948. Since that time, many techniques for the intercorporal fusion of the spine have been reported. These include tibial or iliac bone grafts, sometimes fixed with screws or plates [6, 9, 12, 17, 20]. This article now describes the new surgical technique for ventral spondylodesis, using a new implant for the interbody fusion of the lumbar and sacral spine. In addition, we describe the indications for ventral spondylodesis and report the results of a rather small follow-up study.

Adult↗