Intra-arterial calcium stimulation with right hepatic vein sampling for insulin gradients is the most sensitive preoperative test for localizing insulinomas.

Calorie and protein supplementation improves nutritional status. This support may improve outcome and decrease morbidity and mortality in acutely brain-injured patients. Investigators have observed a poor tolerance to enteral feedings after brain injury and have noted that this persists for approximately 14 days postinjury. This delay has been attributed to increased gastric residuals, prolonged paralytic ileus, abdominal distention, aspiration pneumonitis, and diarrhea. In the present investigation, 23 brain-injured patients with an admission 24-hour peak Glasgow Coma Scale (GCS) score between 4 and 10 were studied for 18 days from hospital admission. The mean duration from injury to initiation of full-strength, full-rate enteral feeding was 11.5 days. Seven of the 23 patients tolerated enteral feedings within the first 7 days following hospital admission (mean 4.3 days), four patients tolerated feedings between 7 and 10 days postadmission (mean 9 days), and 12 patients did not tolerate feedings until after 10 days postinjury (mean 15.9 days). There was a marginally significant relationship between low GCS scores on admission and length of days to enteral feeding tolerance (p = 0.07). A significant inverse relationship was observed between daily peak intracranial pressure (ICP) and time to tolerance of feedings (p = 0.02). There was no significant relationship between feeding tolerance and days to return of bowel sounds (p = 0.12). Serum albumin levels decreased during the investigation (mean +/- standard error to the mean: 3.2 +/- 0.12 gm/dl on Day 1; 2.7 +/- 0.23 gm/dl on Day 16; normal = 3.5 to 5.0 gm/dl), whereas the percentage of patients tolerating feedings increased over the course of the study. The authors conclude that patients with acute severe brain injury do not adequately tolerate feedings via the enteral route in the early postinjury period. Tolerance of enteral feeding is inversely related to increased ICP and severity of brain injury. It is suggested that parenteral nutritional support is required following brain injury until enteral nutrition can be tolerated.

These results suggest that subtle subclinical changes in motor function are present in presymptomatic individuals who have inherited the HD allele.

The rationale for using an approximate t′ test of the difference between the means of MZ and DZ twins is presented. This test avoids pooling the among-MZ and among-DZ twin-pair mean squares and has approximate degrees of freedom based upon the relative number of MZ and DZ twin pairs as well as the relative sizes of the among-MZ and among-DZ twin-pair mean squares. Sampling experiments simulating twin studies were used to show that the rate of Type I error for this t′ test was appropriate while other tests could give either too many or too few Type I errors depending upon the relative sizes of the mean squares and the relative numbers of MZ and DZ twin pairs.

Plasma cholesterol was measured in the fifth decade of the life of 249 pairs of monozygotic (MZ) and 262 pairs of dizygotic (DZ) World War II veteran twins and 70% of the same cohort 10 years later. There were no significant differences between the mean cholesterol values for MZ and DZ twins, and the within DZ pair mean squares were significantly larger than the within MZ pair mean squares for all of the cholesterol variables measured. However, the DZ twins were found to have greater total variance, positive skewness, and leptokurtosis than the MZ twins for total and high-density lipoprotein cholesterol, and the total/high-density ratio. Comparisons with published data revealed that the variance of DZ twins was similar to that of singletons while the MZ twins have smaller total variance, perhaps owing to a missing component of variation. Hypotheses for the source of the differences in the zygosity distributions are proposed including environmental influences (pre- or post-natal and within- or among-families), genetic differences, and selection at the time of induction into the armed services. Because of the differences in total variance of the two zygosities it is difficult to know which estimates of genetic variance or heritability have the least bias. However, these data provide clues that may lead to further understanding of sources of plasma cholesterol variation that could be important to the future understanding of risk for coronary heart disease.