Cognitive and psychosocial functioning of patients with congenital nephrogenic diabetes insipidus.

Mental retardation (MR) is generally considered one of the main complications of congenital nephrogenic diabetes insipidus (NDI). However, psychometric studies of NDI patients are scarce and outdated. In the present study, 17 male NDI patients underwent psychological evaluation. Total intelligence quotient of 14 patients was within (n = 13) or above (n = 1) the normal range, 1 patient had an intelligence score between -1 and -2 standard deviations (S.D.) and 2 young patients had a general cognitive index more than 2 S.D. below the norm. Attention deficit hyperactivity disorder criteria were met by 8 out of 17 patients and scores on short-term memory were low in 7 out of 10. No relation between test performances and age at diagnosis or hypernatremia could be found, with the exception of a negative correlation between age at start of therapy and verbal IQ in one age group. Although several explanations for an association between MR and NDI can be postulated, it seems that the current prevalence of MR among patients with this disease is considerably lower than suggested in literature.

Community-based study of the incidence of gastrointestinal diseases in The Netherlands.

The incidence of gastrointestinal diseases was studied in a community-based study in four regions of The Netherlands. Two grades of severity were distinguished--1: diarrhoea or vomiting and at least 2 additional symptoms within the period of 1 week, and 2: diarrhoea or vomiting and at least 2 additional symptoms occurring on the same day lasting at least 2 days within the period of 1 week. The incidence of gastrointestinal episodes was calculated to be 630 for grade 1 and 180 for grade 2 disease per 1000 person-years, after correction for age and sex. The incidence was higher for women than for men (relative risk 1.25) and lower for those in the 19-64-year-old age group when compared to those younger or older (relative risk 0.75 and 0.40, respectively). Independent of the degree of severity of the symptoms, about 20% of the patients had consulted a general practitioner, about half in person and half by telephone. It is concluded that community studies are essential to assess the real incidence of gastrointestinal diseases in the population.

Effect of positive genetic trend for mature size on age-of-dam adjustment factors for weaning weight in Angus field records.

Weaning weight and postweaning gain field data from the American Angus Association were used to estimate age-of-dam adjustment factors for 205-d weaning weight. A two-trait model was used to take into account all genetic information available in the breed. Correction factors were developed for age-of-dam categories by sex of calf and management (creep or no creep) within maternal-grandsire birth-year groups. The maternal-grandsire birth-year groups were included to determine the need for updating age-of-dam adjustment factors for weaning weight. The mathematical model for 205-d weight included an overall mean, weaning contemporary group, age of dam by sex of calf and management code within maternal-grandsire birth-year group, animal direct effect, maternal genetic effect, permanent environmental effect, and residual error. The model for postweaning gain included an overall mean, postweaning contemporary group, animal direct effect, and residual error. Age-of-dam additive adjustment factors differed from the current factors used for the Angus breed. Young dams did not receive as large an adjustment as the current Angus adjustments recommended. Grouping the age-of-dam categories by birth year of maternal grandsire yielded different additive adjustment factors for 205-d weight. Noncreep calves tended to have larger age-of-dam adjustments than creep-fed calves did. Results indicate the need to consider including age of dam as a fixed effect in the animal model evaluation, so that adjustment factors may be specific to the genetic changes for growth in the breed.

Effects of cadmium on reproduction, an epizootologic study.

The Dutch part of Kempenland has been exposed to cadmium pollution since the last century. Experimental data suggest effects by cadmium on reproduction such as diminished fertility, decreased foetal growth, and specific malformations. Use was made of a historical cohort of dairy cows, ascertained from a surveillance program conducted by the regional Veterinary Health Service between 1976 and 1986. Ten dairy farms in the cadmium region were matched by size with 40 dairy farms from a reference area. Logistic models were used to calculate Odds (OR) and Rate Ratios (RR) and their 95% confidence interval. In total 4,039 exposed and 15,552 reference gestations were compared. The reasons for the slaughter of 574 exposed and of 2,824 reference cows were ascertained. A lower twinning rate [OR = 0.63 (0.47-0.84)] was found and more birth complications, for both calves [OR = 1.50 (1.25-1.80)] and cows [OR = 1.49 (1.24-1.79)]. More inseminations [OR = 1.20 (1.01-1.43)] were needed for conception in the exposed area. Deaths among twins [OR = 1.66 (0.90-3.07)] were not significantly higher. Perinatal death, premature death, age at, or reasons for, slaughter were not consistently different. These results are consistent with those of other observational and experimental studies. Extrapolation from these large domestic animals to humans is problematic, as is the more frequent extrapolation from rodents to humans. It can be concluded that longterm exposure to low levels of cadmium is associated with impaired reproduction in dairy cows.

Calculation of the EC50 and its confidence interval when subtoxic stimulus is present.

In many experiments in toxicology and ecotoxicology with continuous response, like growth, a stimulus is found for low doses, while higher doses are toxic. This subtoxic stimulus is called hormesis. The standard logistic model cannot be used when hormesis occurs. A model is given which can describe this phenomenon. The model has the EC50 as one of its parameters. This has the advantage that the EC50 and its confidence interval can be determined directly by nonlinear regression. Also, the tests for the presence of hormesis and lack of fit are described.