Clinical and radiographic diagnosis of occlusal caries: a study in vitro

We report on the autopsy study of a premature boy with multiple joint contractures who died soon after birth of severe lung hypoplasia. Muscle histology showed PAS-positive vacuoles, and electronmicroscopy revealed massive subsarcolemmal and intermyofibrillar accumulation of glycogen. Biochemical analysis of fresh-frozen muscle tissue disclosed increased glycogen content and a complete lack of phosphofructokinase (PFK) activity. The brain showed focal cerebral and diffuse cerebellar white matter gliosis, and patchy loss of internal granular and Purkinje cells in the cerebellar cortex. The spinal cord was normal. This report describes the first case of PFK deficiency, presenting as a lethal fetal akinesia sequence.     

Effects of gravity on tracheal mucus transport rates in normal subjects and in patients with cystic fibrosis

A noninvasive, radionuclide imaging technique for measuring the rate of mucus clearance in the trachea (RT), was used to study gravitational effects on mucus clearance in 13 patients with cystic fibrosis (CF), average age 17 years; 7 normal, nonsmoking adults, average age 26 years; and a normal subject who was recovering from an acute upper respiratory tract infection (URTI). In the upright position, nine of the CF patients and the subject with URTI demonstrated abnormal tracheal mucus clearance which approached normal when they were placed in 25 degrees headdown position. The normal subjects and two of the CF patients showed no significant difference in the RT measured in the two positions. The results of the study indicate that the force of gravity can be a major influence on tracheal mucus clearance in CF and URTI subjects. This conclusion supports the use of postural drainage as an effective form of therapy in patients with cystic fibrosis.     

Role of the kidney in regulating plasma immunoreactive beta-melanocyte-stimulating hormone

An analysis of the factors that influence the increase in plasma immunoreactive beta-melanocyte-stimulating hormone (beta-MSH) concentration in chronic renal failure showed that: (a) the increase correlated with the increase in serum creatinine concentrations; (b) beta-MSH was not cleared from the plasma by haemodialysis; (c) beta-MSH concentrations increased with length of time on dialysis and increased further after bilateral nephrectomy but there was no further increase with time; (d) beta-MSH levels decreased to normal after renal transplantation; and (e) beta-MSH was excreted in urine only when plasma levels rose to well above those of chronic renal failure (in Nelson's syndrome). These findings suggest that the kidney regulated plasma beta-MSH by a non-excretory mechanism and is the major site of beta-MSH metabolism.     

Serum cortisol (hydrocortisone) values in normal dogs as determined by radioimmunoassay

A radioimmunoassay method was utilized to determine serum cortisol (hydrocortisone) concentrations in normal dogs. The mean value was 2.32 mug/dl (minimum, 0.94; maximum, 3.70; with a coefficient of variation of 29.7%). Samples had been collected in the morning of the diurnal cycle. The cortisol antibody used was highly specific for cortisol and showed little cross reaction with other common physiologic corticosteroids, when they were assayed, using the radioimmunoassay procedure described.     

Augmented water binding and low cellular water content in erythrocytes of camel and camelids

We investigated a link between hemoglobin primary structure, hemoglobin hydrophobicity-hydrophilicity, and erythrocyte water content in various mammalian species. Some hemoglobin molecules, particularly those of the camel and camelids, contain more charged amino acid residues and are more hydrophilic than the hemoglobins of human and a number of other mammalian species. To test the in vivo significance of these alterations of hemoglobin primary structure, we determined the osmotically unresponsive erythrocyte water fractions in mannit solutions of various osmolarities at 4 degreesC. Among the species investigated, the size of the osmotically unresponsive erythrocyte water fraction relates in a positive linear way to hemoglobin hydrophilicity. The extreme low total erythrocyte water content of camel erythrocytes (1.1-1.3 g water/g dry mass) may be explained by a comparatively high osmotically unresponsive erythrocyte water fraction. It is proposed that alterations of hemoglobin sequences of camel and camelids may be the part of a natural selection process aimed at protecting these animals against osmotic dehydration in arid environments.