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Biomedical subjects

T H Mitchell

Publications and source records attributed to T H Mitchell.

At least 19 recordsLinked to original sources
PubMed1997

Microalbuminuria in patients with non-insulin-dependent diabetes mellitus relates to nocturnal systolic blood pressure.

PURPOSE: Microalbuminuria predicts early mortality in non-insulin-dependent-diabetes mellitus patients (NIDDM). Our objective in the present study was to compare and assess the relationship between 24-hour, day and nocturnal ambulatory blood pressure (BP) and urinary albumin excretion rate (UAE) in microalbuminuric and normoalbuminuric NIDDM and in normal control subjects. PATIENTS AND METHODS: In the present cross-sectional study, 24 hour ambulatory BP (daytime BP and nocturnal BP) and HbA1c were compared in microalbuminuric (n = 10) and nonmicroalbuminuric NIDDM patients (n = 10) and in nondiabetic controls (n = 9). None of the patients were taking antihypertensive agents. RESULTS: In the microlbuminuric group, whereas 24 hour and daytime systolic BP differed significantly from control values (P < 0.025 and P < 0.05 respectively), there was no difference between diabetic groups. However, nocturnal systolic BP in the microalbuminuric group was significantly higher than in the normoalbuminuric diabetic patients (139 vs. 125) (P < 0.05) and a significant difference was also found between the NIDDM patients and the control group (139, 125 vs. 114) (P < 0.025). In multiple regression analysis, only nocturnal systolic BP showed a significant relationship with UAE (P < 0.05). CONCLUSIONS: We suggest that the higher nocturnal systolic blood pressure seen in our microalbuminuric NIDDM patients may contribute to the increased morbidity in this group.

Adult↗
PubMed1996

Medial arterial calcification, calcific aortic stenosis and mitral annular calcification in a diabetic patient with severe autonomic neuropathy.

Medial arterial calcification (Mönckeberg's arteriosclerosis) is well described in diabetic patients with autonomic neuropathy. There is also a high prevalence of diabetes mellitus among subjects with calcific aortic stenosis and mitral annular calcification. We describe a diabetic patient with autonomic neuropathy and extensive medial arterial calcification who also had calcification of the aortic valve and of the mitral valve annulus. We propose that autonomic neuropathy may play a role in calcification of these structures at the base of the heart.

Adult↗
PubMed1993

Constrictive pericarditis simulating intestinal lymphangiectasia in a patient with the Noonan syndrome.

A case of constrictive pericarditis with marantic endocarditis in a patient with the Noonan syndrome is reported. Congenital heart defects are often diagnosed in the Noonan syndrome and are undoubtedly the most problematic of its pathologies. Our patient had surgery for pulmonic stenosis at age 10 and 16 years. Over a period of 1-2 years prior to death at age 23 years, he developed elevated jugular venous pressure, hypoproteinaemia, pedal oedema and pleural effusions. The hypoproteinaemia and resulting signs were initially attributed to intestinal lymphangiectasia. The latter, unlike constrictive pericarditis, has been reported in the Noonan syndrome. Post-mortem examination revealed constrictive pericarditis with a marantic endocarditis. There was no evidence of intestinal lymphangiectasia.

Adult↗
PubMed1993

Microalbuminuria in NIDDM.

OBJECTIVE: To determine an effective screening procedure for microalbuminuria. RESEARCH DESIGN AND METHODS: The prevalence of microalbuminuria in NIDDM patients whose urine was negative on routine Albustix testing was studied. Microalbuminuria was measured in overnight urine samples from 128 NIDDM patients on at least two of three occasions over a 6-mo period. Patients were tested with Micro-Bumintest or Micral-Test. RESULTS: Ten of 128 patients had albumin concentrations > or = 20 mg/L on two or more occasions, 14 patients had A-C ratios > or = 3 mg/M on two or more occasions, and 9 patients had both. CONCLUSIONS: Neither Micro-Bumintest nor Micral-Test is a useful or feasible screening procedure for microalbuminuria.

Aged↗
PubMed1991

Effects of sodium supplementation during energy restriction on plasma norepinephrine levels in obese women.

We tested whether sodium restriction would counteract the decrease in sympathetic nervous system activity usually associated with marked energy restriction. The effects of two levels of energy restriction, with different sodium intakes, on plasma norepinephrine (NE) levels while supine and in response to standing were studied. Twenty-two healthy normotensive obese female subjects (body mass index, 34 +/- 1 kg/m2; weight, 90 +/- 2 kg) followed one of three 3-week protocols: 1) total fasting with 80 mmol/day NaCl, 2) a very low energy diet (VLED) containing 1.7 MJ, 93 g protein, and 90 mmol Na/day, with an additional 60 mmol/day NaCl supplement, or 3) total fasting without NaCl (0 Na fast). At the end of the baseline isocaloric diet and of total fasts or VLED, pulse, blood pressure, and plasma NE were measured after 4 h of recumbency and 5 and 10 min after assuming the upright posture. These measurements were repeated after 1 L physiological saline was infused into the 0 Na fast subjects. Cumulative negative sodium balance was observed only in the 0 Na fasting subjects. Supine blood pressure decreased from baseline with fasting, but not with the VLED. The decreases in systolic pressure and increases in heart rate on standing observed with all diets were greatest with the 0 Na fast. Supine plasma NE (vs. baseline value) declined (P less than 0.05) with the VLED, remained unchanged with the Na supplemented fast, but increased with the 0 Na fast (P less than 0.05). The upright plasma NE values were highest in the 0 Na fast subjects, but lower after the saline infusion as well as in the subjects on the VLED. Thus, the decrease in NE due to energy restriction with normal sodium intake was counteracted by moderate sodium restriction, and levels increased with zero sodium intake. Therefore, sodium depletion can override the suppressive effect of energy restriction and, instead, increase the activity of the sympathetic nervous system, as reflected by plasma NE.

Adult↗
PubMed1990

Intravenous bicarbonate and sodium chloride both prolong endurance during intense cycle ergometer exercise.

To determine the effects of neutralizing exercise systemic acidosis via the intravenous route upon endurance and metabolic responses, eight lean, normal, postabsorptive men exercised to exhaustion at about 80% of their VO2 max (69 +/- 3%, mean +/- SEM, of maximum power output) on a cycle ergometer. Exercise studies were performed either with no infusion (control) or with a total infusion volume of about 1.5 L, mainly as 1.3% sodium bicarbonate or as 0.9% sodium chloride (NaCl), infused (double-blind) throughout exercise. The sodium bicarbonate was to prevent acid-base change, the sodium chloride was as a control for the volume infused. Arterialized venous blood and breath-by-breath analysis of expired gases were obtained. [H+] (nmol.L-1) and [HCO3-] (mmol.L-1) at exhaustion were similar in control and NaCl (46.5 +/- 1.8, 19.9 +/- 0.9), but remained unchanged from rest values with bicarbonate (38.4 +/- 0.9, 24.8 +/- 1.5, p less than 0.005 vs control and NaCl). At exhaustion, VO2, VCO2, RER, heart rate, and systolic BP as well as FFA, glycerol, alanine, insulin, norepinephrine, and epinephrine did not differ among protocols. Endurance was markedly prolonged (p less than 0.01) with bicarbonate (31.9 +/- 5.8 min) and NaCl (31.8 +/- 4.1 min) compared with the control (19.0 +/- 2.9 min) condition. Plasma glucose at exhaustion was higher (p less than 0.025) in the control compared to bicarbonate and NaCl experiments, while lactate was higher (p less than 0.025) in the bicarbonate than in the control and NaCl experiments. Thus, the prolonged endurance with sodium bicarbonate infusion could not be explained either by its effect of maintaining blood acid-base equilibrium or concomitant metabolic changes.

Acid-Base Equilibrium↗
PubMed1989

Effects of BRL 35135, a beta-adrenoceptor agonist with novel selectivity, on glucose tolerance and insulin sensitivity in obese subjects.

BRL 35135 is a novel oral agent which, when dosed chronically to obese rodents with abnormal glucose tolerance, improves both insulin sensitivity and glucose tolerance. To study its effect in man, 10 obese patients on a weight-maintaining diet received BRL 35135 2 mg four times per day for 5 days and then 6 mg four times per day for 5 days. Oral 100 g glucose tolerance tests were performed 1 day prior to and 12 h after the 10-day treatment with BRL 35135. Simultaneously, energy expenditure, glucose oxidation and glucose storage were measured by open-circuit indirect calorimetry. No significant changes in body weight occurred during the 10-day treatment with BRL 35135. Areas under the curves for glucose and insulin were reduced following treatment with BRL 35135 (1518 +/- 152 to 1277 +/- 132 mmol/1/3 h, P less than 0.001 and 13.8 +/- 1.7 to 9.5 +/- 1.3 U/l/3 h, P less than 0.01) (mean +/- s.e.m.). In addition, plasma glucose concentrations, 2h post-oral glucose, were reduced significantly (8.7 +/- 1.0 mmol/l to 6.7 +/- 0.78, P less than 0.01). There was no effect of the treatment on glucose-induced thermogenesis and glucose oxidation did not change but glucose storage increased significantly. The results suggest that BRL 35135 improves glucose tolerance by an increase in insulin sensitivity that is independent of body weight. Glucose storage accounted for the increased glucose disposal.

Adult↗
PubMed1988

Relationship between neonatal birth weight and maternal plasma amino acid profiles in lean and obese nondiabetic women and in type I diabetic pregnant women.

Profiles of hemoglobin A1c (HbA1c) and concentrations of plasma glucose and 18 plasma amino acids were obtained in ten nonobese, insulin-dependent type I diabetic women, in 9 age- and weight-matched normal women and in ten obese nondiabetic women throughout pregnancy and postpartum. In late gestation, the period of maximum fetal growth, average HbA1c, plasma glucose, and total amino acid concentrations in diabetic mothers were significantly elevated above lean control values. No differences existed between the obese and lean control groups. Lean diabetic mothers also had significantly heavier babies (mean +/- SEM) relative to the 50th percentile for gestational age and sex (119 +/- 9%) than did the lean control group (94 +/- 3%, P less than .05). Relative birth weights among control lean and obese mothers did not differ significantly (94 +/- 3% v 104 +/- 5%). Late pregnancy profiles of HbA1c and average plasma glucose did not correlate with relative weight of neonates whereas average total plasma amino acids and six individual amino acids did correlate with this parameter. These data suggest that maternal plasma amino acid concentrations may influence fetal weight generally and may have an important role in the development of fetal macrosomia in diabetic pregnancies.

Adult↗
PubMed1988

Hyperglycemia after intense exercise in IDDM subjects during continuous subcutaneous insulin infusion.

Exercise is conventionally considered a modality for improvement of glycemia in diabetes. We have found that a short period of intense exercise (80% VO2max) in normal lean subjects produces sustained postexercise hyperglycemia 20% above basal with a corresponding 100% increase in plasma insulin. In people with insulin-dependent diabetes mellitus (IDDM) incapable of this insulin response, it was predicted that postexercise hyperglycemia would be of greater magnitude and/or duration. To investigate this possibility, the effects of the same intense exercise (80% VO2max) were studied in 8 IDDM subjects (2 on 2 occasions) in the postabsorptive state with continuous subcutaneous (abdominal) insulin infusion (CSII). When the preexercise plasma glucose was normal (n = 6, 86 +/- 4 mg/dl), there ensued a postexercise hyperglycemia to 127 +/- 7 mg/dl (P less than .001) sustained for 2 h postexhaustion. Plasma free immunoreactive insulin (IRI) was 1.43 +/- 0.12 ng/ml before exercise and did not change postexercise. When mean preexercise plasma glucose was 149 +/- 9 mg/dl (n = 4), it rose progressively throughout the 2 h of recovery to 229 +/- 28 mg/dl (P less than .025). A small but statistically significant decrease in free IRI occurred during the last 80 min of recovery. Hyperglycemia in the diabetic subjects was not explained by abnormal or differing responses of glucagon or catecholamines. Thus, with intense exercise, diabetic control deteriorates rather than improves. Therefore, different therapeutic strategies may be required for intense compared with moderate exercise in IDDM patients.

3-Hydroxybutyric Acid↗
PubMed1984

Isolated hypogonadotropic hypogonadism with syndactyly.

Although some skeletal malformations have been associated with hypogonadotropic hypogonadism, syndactyly, to our knowledge, has not. A 43-year-old man, with no family history of either condition, was identified as having isolated hypogonadotropic hypogonadism with syndactyly of the feet.

Adult↗
PubMed1973

Nursing education.

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Education, Nursing↗