Left ventricular hypertrophy and ambulatory blood pressure monitoring in chronic renal failure

BACKGROUND: Left ventricular hypertrophy (LVH) is both common and an important predictor of risk of death in end-stage renal failure (ESRF). In mild to moderate chronic renal failure (CRF), the timing of onset of LVH and the factors involved in its initial development have not been fully elucidated. The present study was undertaken to examine the prevalence and potential determinants of echocardiographically determined LVH in this connection, and to compare 24-h ambulatory blood pressure (BP) recordings with BP measured at a previous clinic visit. METHODS: From a cohort of 120 non-diabetic patients who had been attending a nephrology clinic, 118 agreed to participate in the study. Of these we selected for analysis 85 stable patients (37 male). Patients with known cardiovascular disease, those with a history of poor compliance with antihypertensive medication, and those in whom such medication had been changed in the previous 3 months were excluded. Clinic BP, 24-h ambulatory BP, echocardiography, body mass index (BMI), serum creatinine (SCr), creatinine clearance (CrCl), haemoglobin (Hb), fasting cholesterol (CHOL), triglyceride TRIGL), plasma glucose, calcium (Ca), phosphate (PO4), alkaline phosphatase (ALK PHOS), parathyroid hormone (PTH) concentrations, and 24-h urinary protein were assessed in all patients. Seventy-seven per cent were on antihypertensive medication. RESULTS: LVH was detected in 16% of patients with CrCL > 30 ml/min, and 38% of patients with CrCl < 30 ml/min. By stepwise regression analysis, ambulatory systolic BP (P < 0.0001), male gender (P < 0.0001), BMI (P < 0.0002), and Hb concentration (P < 0.002) were the only independent determinants of left ventricular (LV) mass. Nocturnal systolic BP (P < 0.02) was the main determinant of LVH in the group of patients with advanced CRF. The correlation between left ventricular mass index (LVMI) and mean 24-h ambulatory systolic BP (r = 0.52, 95% confidence interval 0.50-0.54) was statistically significantly stronger than with outpatient systolic BP (r = 0.25, 95% confidence interval 0.23-0.27). The same was true for the correlation between LVMI and mean 24-h ambulatory diastolic BP (r = 0.42, 95% confidence interval 0.40-0.44), and outpatient diastolic BP (r = 0.22, 95% confidence interval 0.20-0.24). CONCLUSIONS: Twenty-four hour ambulatory BP recording and echocardiography are required for accurate diagnosis of inadequate BP control and early LVH in patients with chronic renal impairment, independent determinants of which are hypertension, male sex, BMI, and anaemia.      

Subsensitivity to the bronchodilator action of albuterol produced by chronic administration.

Evidence of bronchodilator subsensitivity was sought in studies using the specific beta2 adrenergic agonist, albuterol. After a period of 1 or 2 weeks off all oral sympathomimetic agents, the mean response of the patients to the first dose of albuterol was consistently greater than the response after a period during which the drug had been administered regularly. Maximal decrease in response occurred after 2 weeks' of treatment, and there was no further decrease after prolonged treatment with the same dose of albuterol for periods as long as 1 year.     

Adoptive transfer of experimental allergic encephalomyelitis from immature guinea pig donors

In immature Strain 13 guinea pigs sensitized to syngeneic spinal cord, a chronic allergic encephalomyelitis is elicited reminiscent of demyelinating diseases of man and which features relapses or progressive downhill course and extensive areas of demyelination in the central nervous system. However, juvenile recipients of syngeneic lymphocytes from similarly sensitized juveniles show only the acute form of experimental allergic encephalomyelitis. Neuropathologically, the CNS of affected animals displayed mild changes only and minimal demyelination. These observations indicate that the age-dependent differences seen between the acute disease of adults and the chronic disease of juveniles may be due to differences in availability of modulating or reparatory factors, rather than differences in the central nervous system organ or in the immune response itself.     

Heterozygote detection in phenylketonuria. Measurement of discriminatory ability and interpretation of the phenylalanine loading test by determination of the heterozygote likelihood ratio.

Two tests of heterozygosity for phenylketonuria, the phenylalanine/tyrosine ratio in the plasma after a fast and the response to an oral load of phenylalanine, have been compared in obligate heterozygotes for phenylketonuria and apparent normal homozygotes. The discriminatory ability of the tests is measured using both parametric and non-parametric methods, the correlation between them is determined, and the reproducibility of the loading test is examined. Because complete separation between the genotypes cannot be achieved by these tests, a method of interpretation which avoids possibly erroneous categoric statements and which enables the family history of a subject and his test result to be combined in a quantitative and meaningful way is described.     

A review of thermal injuries in young children

A group of 472 children under 3 yr of age were treated for thermal injuries in a 5-yr period; 65% were boys. Injuries were due mainly to scalding (82%) and involved predominantly the upper part of the body. Full thickness skin loss resulted in 30% of cases, and skin grafting was needed in 29%. Forty-two episodes of infection arose, and 50 patients (11%) developed other complications--hyperpyrexia, respiratory problems, fluid imbalance and convulsions were the commonest. The mortality rate was 1% (4 cases) and the mean duration of stay in hospital was 17 days. The plan of management is outlined with emphasis on the essential differences in treatment of young children, and the results are reported.     

Basal lamina formation by astrocytes in organotypic cultures of mouse spinal cord tissue

The relationship between astrocytes, basal lamina and mesenchymal tissue was analyzed ultrastructurally in myelinated organotypic cultures of mouse spinal cord tissue grown in combination with its pia-arachnoid membrane. A discontinuous, well-developed basal lamina covered flat astrocytic processes which formed the basal layer of the explant opposing the pia-arachnoid membrane. Some astrocytic processes on the surface facing the pia-arachnoid membrane lacked basal lamina, had an irregular surface with microvillus-like protrusions but within the explant they formed intercellular chambers which were surrounded by basal lamina. Even in the presence of mesenchymal tissue which appeared to facilitate the formation of basal lamina in this system, the absence of basal lamina on some areas of the astrocytic plasma membrane suggests regional differences of the astrocytic processes and might reflect the epithelial nature of the astrocyte.