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Biomedical subjects

J T Hayford

Publications and source records attributed to J T Hayford.

9 recordsLinked to original sources
PubMed1979

Triglyceride concentrations: the disaccharide effect.

The mean 24-hour or integrated concentration of triglyceride is significantly higher when dietary sucrose is provided rather than an equivalent amount of its component monosaccharides, glucose and fructose. In contrast, the plasma triglyceride concentration after a 12-hour fast is not significantly different.

Adult↗
PubMed1979

Triglyceride integrated concentrations: effect of variation of source and amount of dietary carbohydrate.

The effect of changes in the amount of dietary carbohydrate (45 or 65% of total energy) and in the source of carbohydrate (sucrose or corn syrup) on plasma triglyceride and cholesterol concentrations was studied in eight healthy males. Subjects ingested each of the four formula diets for 10 days in a latin square sequence. Diet-induced response was assessed by measurement of plasma lipid concentrations in blood obtained after overnight fast and by measurement of the mean plasma lipid concentrations--designated the integrated concentration--of blood obtained by 24 hr continuous blood withdrawal. The fasting plasma triglyceride concentration increased significantly during ingestion of the high carbohydrate diet (P less than 0.005) but was not significantly influenced by the source of carbohydrate calories. The 45% carbohydrate diets induced larger meal associated plasma triglyceride variation than 65% diets. Sucrose-containing diets induced significantly higher plasma triglyceride integrated concentrations than corn syrup diets, whether provided as 45% (P less than 0.05) or 65% (P less than 0.005) of total energy. Diet-induced changes in fasting or integrated plasma cholesterol concentration were minimal.

Adult↗
PubMed1972

Serum thyrotropin responses to synthetic thyrotropin-releasing hormone in normal children and hypopituitary patients. A new test to distinguish primary releasing hormone deficiency from primary pituitary hormone deficiency.

Synthetic thyrotropin-releasing hormone (TRH) was administered intravenously in a dose of 7 mug/kg to 20 normal children ages 4-13 yr. Serum thyroid-stimulating hormone (TSH) was measured by radioimmunoassay and rose from a mean value of 1.7 muU/ml (range = < 1.25-7.2) to a mean peak value of 21.5 muU/ml (5.2-33.2) at 15 or 30 min after administration.13 patients with idiopathic hypopituitarism and apparent normal thyroid function, ages 3-19 yr, responded to TRH in a manner very similar to the control subjects: TSH rose from a mean value of 1.8 muU/ml (range < 1.25-4.3) to a mean peak value of 18.5 muU/ml (range = 9.5-45.0) which occurred between 15 and 60 min after TRH.13 idiopathic hypopituitary patients with documented thyroid deficiency were tested after thyroid therapy had been discontinued for a minimum of 10 days. The serum TSH values in 10 of 13 patients rose from a mean base line level of 2.2 muU/ml (< 1.25-5.3) to a peak mean value of 32.5 muU/ml (9.6-61.3) between 30 and 120 min after TRH. In three patients, however, little or no TSH response was detected, even when serum thyroxine levels were extremely low. Similar to the latter group, three of five patients with hypopituitarism secondary to craniopharyngiomas had undetectable or barely measurable TSH levels before and after TRH. Two of these five patients had significant responses which were compatible with hypopituitarism resulting from damage to the hypothalamus or hypothalamic vessels instead of the pituitary. Side effects were experienced in 41 of 54 patients (76%). The effects were limited to a mild nausea-like sensation in 63% of the patients and occurred within the first 5 min after receiving TRH. No evidence of serious toxicity or long-term side effects was noted. The TRH test is a safe, effective way to measure TSH reserve in children. The positive response in 10 of 13 patients with secondary hypothyroidism supports data previously accumulated that most patients with idiopathic hypopituitarism have an abnormality of their hypothalamic-releasing hormone function, whereas the remaining minority probably have primary pituitary disease.

Adolescent↗
PubMedDate not supplied

Factors related to grade retention in children with short stature.

A recent study by Holmes et al. (1982) revealed a high degree (23%) of grade retention in a group of children with significant short stature secondary to growth hormone deficiency (GHD), constitutional delay (CD); or Turner's Syndrome (TS). Parents indicated in a free response format that 'immaturity' and 'small size' were the reasons for retention. The present follow-up study obtained academic achievement data on 47 of the 56 short children from the Holmes et al. (1982) study to assess what role academic factors, not spontaneously mentioned by parents, may have had in the retention decision. Results indicated that despite repeating a year in the primary grades, the group of retained children were still functioning 6 months below grade expectation, compared to grade appropriate achievement in the never-retained group. Parents and teachers were both accurate in their perceptions of children's academic achievement. Behavioural ratings by teachers indicated more adjustment difficulties for retained children, while parent ratings of behaviour showed a similar high level of problems for short children regardless of retention status. Although both groups of children possessed average intellectual abilities, the retained children obtained lower IQ scores than the never retained children. In summary, a majority of short children were achieving appropriate grade levels, but a substantial minority were experiencing under-achievement, behaviour problems, and grade retention, despite average intelligence.

Achievement↗
PubMedDate not supplied

Validity of urine glucose measurements for estimating plasma glucose concentration.

Both physicians and diabetic patients have traditionally relied on measurement of glycosuria as an indirect method of estimating plasma glucose concentration to guide adjustment of insulin and diet therapy. Our observations on the correlation between mean plasma glucose concentration with simultaneous urine glucose concentration or excretion rate re-emphasize the limitations of this approach. Although our observations show a significant correlation (P less than 0.0001) between plasma glucose concentration and urine glucose concentration or urine glucose excretion rate, the wide confidence limits [95% confidence limits (minimum) +/- 150 mg/dl] on plasma glucose concentration estimated from urine glucose measurements limit the clinical applicability of such estimates. Differences among subjects in the renal resorption of glucose contribute to the wide variance of estimates. However, significant variability in renal glucose resorption within individuals is documented, further reinforcing the limitations of urine glucose determinations for reliable estimates of plasma glucose concentrations. Diabetologists need to reconsider the applicability of urine glucose measurements in evaluation of adequacy of therapy and in adjustment of insulin dosage.

Adolescent↗
PubMedDate not supplied

A survey of cognitive functioning at difference glucose levels in diabetic persons.

Cognitive functioning was assessed in diabetic patients during hypoglycemia (60 mg/dl), euglycemia/control (110 mg/dl), and hyperglycemia (300 mg/dl). Blood glucose levels were set and maintained to within 4% of targeted levels by an artificial insulin/glucose infusion system (Biostator). Attention and fine motor skills, assessed by visual reaction time, was slowed at altered glucose levels. Performance was less impaired during hyperglycemia than hypoglycemia when a longer interstimulus interval was used, although it was still slower than normal. The time required to solve simple addition problems was increased during hypoglycemia, although reading comprehension was not affected. The possibility that some automatic brain skills are disrupted at altered glucose concentrations is discussed, while associative or inferential skills may be less affected.

Attention↗