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C J Thompson

Publications and source records attributed to C J Thompson.

At least 145 records · Page 8Linked to original sources
PubMed1989

Selection of neighborhood controls for a study of coronary artery disease.

This report describes the selection process for a neighborhood control group recruited between February 1985 and July 1986 to augment a hospital-based case-control study investigating the relation of traditional and nontraditional risk factors to coronary artery atherosclerosis. A total of 219 cases with angiographically defined coronary artery disease residing within a 60-mi (96-km) radius of Winston-Salem, NC, were assigned to surveyors to be matched. Thirty-seven per of the study population were rural, 92% were white, 58% were male, and 52% were older than 50 years of age. One hundred and eighty-seven controls were age-(+/- five years), sex-, and race-matched pairwise to cases. After locating the residence of the case, the surveyor systematically visited neighboring households to ascertain eligibility status of residents. To achieve a match, a maximum of three visits was made to the neighborhood; up to 25 households were surveyed per visit. Refusal rate was less than 5% of eligible matches. Young white urban males were the easiest to match, while rural females, especially older persons, were the most difficult. Average time to complete an assignment included 129 minutes for travel, 237 minutes for surveying the neighborhood, and 62 minutes for clerical tasks. Average distance traveled was 85 mi (136 km) per case. As expected, the time and distance to complete a case were greater in rural than urban areas. The average cost per case was $122.97.

Age Factors↗
PubMed1989

Osmoregulation of thirst and vasopressin secretion in Kallmann's syndrome.

It has been suggested that abnormalities of thirst and vasopressin secretion commonly coexist with Kallmann's syndrome. Out-patient plasma osmolality, plasma sodium and 24-hour urine volume were similar in 10 patients with Kallmann's syndrome and 10 matched controls. Six patients underwent dynamic testing of osmoregulation with hypertonic sodium chloride infusion. There were similar rises in plasma AVP concentration in patients (0.4 +/- 0.1-6.2 +/- 1.2 pmol/l, P less than 0.001) and controls (0.4 +/- 0.1-5.7 +/- 1.0 pmol/l P less than 0.001). Thirst ratings rose in similar fashion in patients (0.7 +/- 0.3-6.2 +/- 1.0 cm, P less than 0.001) and controls (1.0 +/- 0.3-7.2 +/- 0.5 cm. P less than 0.001). Drinking rapidly abolished thirst and lowered AVP concentrations in both groups before major changes in plasma osmolality occurred. Linear regression analysis defined similar osmotic thresholds for thirst onset and vasopressin release in the two groups, and there was no difference in the calculated sensitivity of the osmoreceptor/vasopressin secretory unit as defined by the slopes of the regression lines. We conclude that osmoregulation is normal in Kallmann's syndrome.

Adolescent↗
PubMed1989

Vasopressin secretion during insulin-induced hypoglycaemia: exaggerated responses in people with type 1 diabetes.

Insulin hypoglycaemia causes a rise in plasma vasopressin concentrations in man and the rat, and vasopressin stimulates glucagon secretion and increases hepatic glucose output in man. Vasopressin has also been suggested to have an important synergistic role with corticotrophin releasing factor in the release of adrenocorticotrophin hormone, and a counter-regulatory role for the hormone has been proposed. As diminished anterior pituitary hormone responses to hypoglycaemia have been reported in diabetes mellitus, we studied the plasma vasopressin responses to insulin-induced hypoglycaemia in 10 patients with established Type 1 diabetes and 10 matched control subjects. Blood glucose fell from 4.5 +/- 0.3 to 1.6 +/- 0.1 mmol l-1 (p less than 0.001) in the diabetic group and from 4.6 +/- 0.2 to 1.5 +/- 0.2 mmol l-1 (p less than 0.001) in control subjects, with delayed blood glucose recovery in the diabetic patients. Plasma vasopressin rose in the diabetic patients from 0.9 +/- 0.2 to 6.9 +/- 2.8 pmol l-1 (p less than 0.001), a significantly greater rise (p less than 0.05) than in the control subjects, 0.8 +/- 0.1 to 2.4 +/- 1.0 pmol l-1 (p less than 0.001). Plasma osmolalities remained unchanged and haemodynamic changes were similar in both groups. There is an exaggerated rise in plasma vasopressin concentrations in diabetic patients in response to insulin-induced hypoglycaemia. The putative mechanisms and potential significance of the exaggerated rise are discussed.

Adult↗
PubMed1989

Thiostrepton-induced gene expression in Streptomyces lividans.

Thiostrepton induced the expression of four proteins (17, 19, 30, and 56 kilodaltons) of unknown function in Streptomyces lividans. The chromosomal gene which encoded the 19-kilodalton protein (tipA) was cloned and sequenced. Transcription of the tipA promoter was induced at least 200-fold by thiostrepton. The tipA 200-fold by thiostrepton. The tipA transcriptional start site (located by S1 mapping and primer extension experiments) was preceded by a 45-base-pair imperfect inverted-repeat sequence which included the -10 and -35 regions of the promoter. Under noninducing conditions in vivo, this might form a cruciform structure which is not recognized by RNA polymerase. A 143-base-pair fragment including this region was cloned into a promoter probe vector, pIJ486. In this plasmid, pAK114, the thiostrepton-inducible tipA promoter controlled the expression of a kanamycin resistance gene encoding an aminoglycoside phosphotransferase. As little as 1 ng of thiostrepton spotted on a lawn of S. lividans(pAK114) induced kanamycin-resistant growth. Other thiostreptonlike antibiotics also induced tipA, but structurally unrelated antibiotics which inhibit translation had no effect. In S. lividans, the promoter could be induced by thiostrepton during either growth or stationary phase. The tipA promoter should be a valuable tool for expression studies in streptomycetes.

Amino Acid Sequence↗
PubMed1989

Applications of a new method for devising bacteriological serotyping schemes.

Greatly simplified serotyping schemes were devised for two organisms, Escherichia coli and Campylobacter jejuni. The mathematical approach developed to improve the E. coli serotyping routine at the National Health Institute in New Zealand was used on three previously published data sets. It had been considered possible that the mathematical method used in the first study was specific to that data set and therefore not applicable elsewhere. This paper verifies that the mathematical method works on two other E. coli collections and on another bacterium, C. jejuni, and therefore greatly strengthens the assertion made in the earlier paper (C.J. Thompson, J. Clin. Microbiol. 25:774-780, 1987) that this mathematical approach has general applications and can be used to produce efficient and effective serotyping schemes in any laboratory choosing to apply the method to its set of sera.

Campylobacter fetus↗
PubMed1989

Effect of blood glucose concentration on osmoregulation in diabetes mellitus.

Poorly controlled insulin-dependent diabetes mellitus is associated with considerable elevations of plasma vasopressin concentrations, although well-controlled diabetics have normal osmoregulated thirst and vasopressin release. We studied the effect of blood glucose concentration on osmoregulated thirst and vasopressin secretion in insulin-dependent diabetes mellitus. Blood glucose was maintained overnight, and for the duration of the study, in either the euglycemic (4-5 mmol/l) or hyperglycemic (10-12 mmol/l) range, and patients underwent infusion of hypertonic (855 mmol/l) sodium chloride solution. Plasma sodium was lower during the hyperglycemic study, but elevation in plasma sodium concentration by infusion of saline caused progressive linear increases in both thirst and plasma vasopressin concentrations in both studies. Linear regression analysis defined lowered plasma sodium thresholds for both thirst appreciation and vasopressin release during the hyperglycemic study, although the sensitivity of the osmoreceptors remained unchanged. Analysis of the data in terms of plasma osmolality, corrected for the increase in blood glucose in the hyperglycemic study, revealed no differences in the osmotic thresholds for thirst or vasopressin release; sensitivity of the osmoreceptors also remained the same. Drinking abolished thirst and lowered plasma vasopressin concentrations before major changes in plasma sodium were observed. These results show that insulin-dependent diabetic patients osmoregulate appropriately when moderately hyperglycemic but that the threshold plasma sodium for vasopressin secretion and thirst appreciation is lowered by an unknown mechanism.

Adult↗
PubMed1989

Osmoregulation of vasopressin secretion in the insulin-withdrawn streptozotocin-treated diabetic rat.

To investigate whether hyperglycaemic ketoacidotic diabetic rats continue to osmoregulate the secretion of arginine vasopressin (AVP), male Wistar rats were injected with streptozotocin (150 mg/kg body weight). Rats rendered diabetic were maintained on protamine-zinc insulin (PZI) for 11 days (insulin-treated rats; n = 35), after which PZI was withdrawn for 72 h in half the rats (insulin-withdrawn rats). Insulin-withdrawn and -treated rats were divided into two groups; one was injected i.p. with distilled water (20 ml/kg) and the other with hypertonic saline (500 mmol NaCl/l; 20 ml/kg), and killed 30 min after injection. Insulin-withdrawn rats (water loaded and osmotically stimulated) were hyperglycaemic (16.5 +/- 0.8 and 16.5 +/- 0.9 mmol glucose/l respectively) and ketotic (2077 +/- 664 and 1474 +/- 170 mumol acetoacetate/l respectively). Insulin-treated rats were euglycaemic and non-ketotic. Osmotic manipulation caused similar changes in plasma sodium in both insulin-withdrawn and -treated rats. Plasma AVP was low in the water-loaded rats (0.6 +/- 0.1 and 4.5 +/- 0.9 pmol/l in the insulin-treated and -withdrawn rats respectively) and increased in rats injected with hypertonic saline (1.2 +/- 1.8 and 35.2 +/- 17.9 pmol/l respectively). There was no evidence of hypotension and hypovolaemia in any group of rats. Linear regression analysis defined the functions: plasma AVP = 2.56 (plasma Na-141), r = +0.63, P less than 0.01 for hyperglycaemic ketotic rats; plasma AVP = 0.83 (plasma Na-146), r = +0.78, P less than 0.001 for insulin-treated animals. The slopes and abscissal intercepts were significantly (P less than 0.05) different.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Vasopressin secretion in the DIDMOAD (Wolfram) syndrome.

The diabetes insipidus which accompanies the DIDMOAD (Wolfram) syndrome is thought to be hypothalamic in origin, though no formal study of vasopressin secretion in the syndrome has been published, and some data in the literature suggest a renal tubular defect. We have studied vasopressin secretion in seven patients with the Wolfram/DIDMOAD syndrome during three dynamic stimuli: an osmotic stimulus (hypertonic saline infusion), hypoglycaemia (insulin tolerance test) and a baroregulatory stimulus (trimetaphan infusion). Hypertonic saline infusion demonstrated three patients to have complete and four to have partial hypothalamic diabetes insipidus; administration of (per nasal) desmopressin excluded nephrogenic diabetes insipidus in all seven patients. Insulin hypoglycaemia failed to stimulate vasopressin release, but trimetaphan-induced hypotension produced significant though subnormal rises in plasma vasopressin in three patients with partial diabetes insipidus, though it produced a negligible rise and no rise in plasma vasopressin in two patients with complete diabetes insipidus. The data suggest a much greater frequency of hypothalamic diabetes insipidus in the Wolfram/DIDMOAD syndrome than is reported, but did not identify nephrogenic diabetes insipidus. The absence of vasopressin responses to non-osmotic stimuli in patients with complete diabetes insipidus suggests global lack of vasopressin secreting neurones, rather than an isolated osmoreceptor defect or selective vasopressin secreting neuronal loss, as the lesion producing diabetes insipidus in the DIDMOAD syndrome.

Adult↗
PubMed1989

The application of a masked orbiting transmission source for attenuation correction in PET.

A new technique for attenuation correction in positron emission tomography is introduced and evaluated. Transmission scans are performed with a point source of 68Ge encapsulated in a lead collimator that masks the source into a fan beam in the scanning plane. The source orbits the patient section at the edge of the slice defining collimator. Only events acquired by detector pairs that are collinear with the source are used to calculate the attenuation coefficients. Events from detector pairs that are nearly collinear are rejected, while those from detector pairs that are far from collinear may be used to acquire a simultaneous emission scan. The coincident event rate per unit source activity is over twice that of rod and ring sources. This technique is compared with calculated outline and ring source attenuation correction techniques in a pie phantom. The linear attenuation coefficient for water was measured as 0.096 cm-1, and 0.094 cm-1 when the water contained 12 kBq/cc 68Ga, compared with 0.085 cm-1 for a ring source. Cerebral glucose utilization rates in a normal volunteer reconstructed with transmission scans performed pre- and postinjection of fluorodeoxyglucose show no significant differences. However, values of cortical glucose utilization average 12% above those measured with the fitted outline method in the highest cuts because of the obliqueness of the skull to the planes examined.

Adult↗
PubMed1989

Patterns of uterine contractions and prolonged uterine activity using three methods of breast stimulation for contraction stress tests.

The contraction patterns in 378 breast-stimulated contraction stress tests administered to 213 women are described. The subjects were assigned sequentially to one of four intervention groups: bilateral manual breast massage, unilateral pump stimulation, heating pad stimulation, and placebo. There was a marked increase in the proportion of tests with three to four contractions in 5-minute intervals after the interventions occurred. Twenty-five percent of all tests showed prolonged uterine activity, occurring most frequently in women with postdate gestations using manual massage or breast pump stimulation. The duration of prolonged contractions ranged from 1.5-8 minutes, with 19% lasting from 4.5-8 minutes. There was no difference in the incidence of fetal heart rate abnormalities between tests with and without prolonged uterine activity, and no late decelerations occurred in tests with tachysystole.

Adolescent↗
PubMed1988

Influx of a choline analog to dog brain measured by positron emission tomography.

The influx of the 11C-labeled choline analog pyrrolidinocholine into tissue was measured in the brain of three dogs by positron emission tomography (PET). During the first 90 s after the intravenous bolus injection of the tracer, transfer of tracer from plasma to tissue was unidirectional. The influx constant for pyrrolidinocholine into intracranial tissue, Kin, was 0.017 ml/g/min (0.008 SD), and the initial volume of distribution, V0, was 0.08 ml/g (0.03 SD). The influx constant was at least five times larger than the value expected if simple diffusion were to account for tissue uptake. The method presented in this paper can be used to investigate the availability of plasma choline and its analogs to the living human brain and other tissue in degenerative diseases affecting the cholinergic system, and to provide in vivo information on a choline transport system.

Animals↗
PubMed1988

Anatomical-functional correlation using an adjustable MRI-based region of interest atlas with positron emission tomography.

A procedure is described for combining anatomical information from magnetic resonance imaging (MRI) or computerized tomography (CT) and functional information from positron emission tomography (PET) in a rapid fashion. MRI data are combined with a procedure for the definition, storage, and recall of anatomically based regions of interest. An atlas of standard regions of interest, defined for a set of 18 parallel planes spaced at 6-mm intervals, provides an initial region of interest template for each patient slice. Global adjustments to scale, orientation, and position are applied to obtain an initial match. Individual regions of interest may then be moved, deleted, or redrawn as needed. The ability to store region of interest templates ensures reproducibility of analysis over long periods and introduces a standardization of analysis technique. In 25 brain structures, the mean coefficient of variation in cerebral glucose utilization rate (CMRGlc) measurements among five neuroanatomically trained observers was reduced from 8.1% for manual region of interest definition to 4.0% using the template approach with MRI. Template analysis for space-occupying lesions such as tumors or infarcts is illustrated with PET data from a stroke study, emphasizing the facility for rapid, reproducible analysis of multifunctional studies. MRI-PET matching for a structurally intact caudate nucleus having reduced CMRGlc in Huntington's disease emphasizes the accuracy of anatomical localization required to quantify small structures.

Adult↗
PubMed1988

Osmoregulation of thirst and vasopressin secretion in insulin-dependent diabetes mellitus.

1. Osmotically stimulated thirst and vasopressin release were studied during infusions of hypertonic sodium chloride and hypertonic D-glucose in euglycaemic clamped diabetic patients and healthy controls. 2. Infusion of hypertonic sodium chloride caused similar elevations of plasma osmolality in diabetic patients (288.0 +/- 1.0 to 304.1 +/- 1.6 mosmol/kg, mean +/- SEM, P less than 0.001) and controls (288.6 +/- 0.9 to 305.7 +/- 0.6 mosmol/kg, P less than 0.001), accompanied by progressive increases in plasma vasopressin (diabetic patients, 0.9 +/- 0.3 to 7.7 +/- 1.5 pmol/l, P less than 0.001; controls 0.5 +/- 0.1 to 6.5 +/- 1.0 pmol/l, P less than 0.001) and thirst ratings (diabetic patients 1.0 +/- 0.2 to 7.1 +/- 0.5 cm, P less than 0.001; controls 1.8 +/- 0.4 to 8.0 +/- 0.5 cm, P less than 0.001) in both groups. 3. Drinking rapidly abolished thirst and vasopressin secretion before major changes in plasma osmolality occurred in both diabetic patients and healthy controls. 4. There were close and significant correlations between plasma vasopressin and plasma osmolality (diabetic patients, r = +0.89, controls r = +0.93) and between thirst and plasma osmolality (diabetic patients r = +0.95, controls r = +0.97) in both diabetic patients and healthy controls during hypertonic saline infusion. 5. Hypertonic D-glucose infusion caused similar elevations in blood glucose in diabetic patients (4.0 +/- 0.2 to 20.1 +/- 1.2 mmol/l, P less than 0.001) and healthy controls (4.3 +/- 0.1 to 19.3 +/- 1.2 mmol/l, P less than 0.001) but did not change plasma vasopressin or thirst ratings.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Osmoregulation of vasopressin secretion and thirst in cyclical oedema.

Osmoregulation of vasopressin release and thirst was studied in the mid-follicular and mid-luteal phases of the menstrual cycle of five patients with cyclical oedema defined by peripheral oedema and weight gain (greater than 3.0 kg) manifest in two consecutive luteal phases. Results are compared to those already obtained in eight healthy women. In the patients, basal plasma osmolality in the mid-luteal phase was significantly lower than in the mid-follicular periods (patients, 283 +/- 1, 287 +/- 1 mOsmol/kg, respectively, mean +/- SEM, P less than 0.05; controls, 282 +/- 1, 286 +/- 1 mOsmol/kg, respectively, P less than 0.05). Plasma osmolality (pOsm) and plasma arginine vasopressin (pAVP) were measured during hypertonic (850 mmol/l) saline infusion in both phases of the cycle; linear regression analyses of these data gave the following mean regression equations, (i) mid-follicular, pAVP = 0.55 (pOsm - 285), r = 0.94 and (ii) mid-luteal, pAVP = 0.42 (pOsm - 281), r = 0.93. The abscissal intercept was significantly different (P less than 0.025). Osmotic threshold for severe thirst onset was lower in the mid-luteal phase compared to the mid-follicular value (296 +/- 1, 299 +/- 1 mOsmol/kg, respectively, P less than 0.01). Basal data and results of thirst onset and theoretical threshold for vasopressin release in response to osmotic stimulation obtained in the patients were similar to healthy control women. We conclude that osmoregulation in cyclical oedema is normal.

Adult↗
PubMed1988

Possible mechanisms responsible for the rise in plasma vasopressin associated with diabetic ketoacidosis in the rat.

The plasma concentration of arginine vasopressin (AVP) is increased in diabetic ketoacidosis (DKA) in man and the rat. Although haemodynamic changes and nausea/emesis may account for the increased secretion of AVP in severe human DKA, they appear not to be responsible in moderate DKA. Streptozotocin-treated rats were studied to investigate other factors possibly involved in the secretion of AVP in DKA. Wistar rats were injected i.p. with streptozotocin (150 mg/kg body weight). Diabetic rats were maintained on 3-4 units protamine-zinc insulin (PZI)/day for 11 days, after which PZI was withdrawn for 3 days in half the rats. The plasma concentration of AVP was greater in rats with DKA than in normal controls (mean 11.4 pmol/l compared with 1.6 pmol/l; P less than 0.05). Rats with DKA had higher plasma osmolality and concentrations of blood glucose, beta-hydroxybutyrate and acetoacetate, but lower plasma carbon dioxide content than diabetic and normal controls (P less than 0.05). There were no differences in plasma levels of sodium, urea or haematocrit between rats with DKA and controls. In a separate study involving the same procedures, daily systolic blood pressure was measured using a tail cuff to occlude arterial inflow to the tail, and subsequent detection of the cuff pressure at which the first arterial pulsation appeared. No significant differences were detected between normal and diabetic rats and rats with DKA. Exponential relationships between plasma osmolality and plasma AVP (correlation coefficient, r = + 0.75; P less than 0.01), and plasma ketone bodies and plasma AVP (r = +0.60; P less than 0.05) were obtained.(ABSTRACT TRUNCATED AT 250 WORDS)

3-Hydroxybutyric Acid↗