Inter-relationships of carbonate, phosphate, monohydrogen phosphate, calcium, magnesium and sodium in uraemic bone: comparison of dialysed and non-dialysed patients

1. Chemical and morphological features of uraemic bone disease were studied by comparison of bone composition in 44 patients with uraemia (12 dialysed and 32 non-dialysed) and 36 control subjects. The significant changes included decreased bone mineral carbonate associated with calcium, a concomitant increase in phosphate, and an increase in magnesium. There was also an increase in osteoid and a reduction in the specific gravity of the compact bone. 2. The most marked changes in bone composition were observed in patients with uraemia of more than 1 year's duration, who had been dialysed. Bone mineral sodium concentrations were not significantly altered in any group. 3. The changes in bone mineral composition appeared to be the result of several simultaneous and/or successive mechanisms: (i) loss of fixed base, calcium carbonate; (ii) replacement of carbonate by phosphate; (iii) the addition of immature bone mineral, which contains high concentrations of phosphate and relatively low concentrations of carbonate. 4. These observations are consistent with earlier views of the bone salt as an indefinite calcium/phosphate/carbonate complex. Variations in bone composition may arise from a reciprocal relationship between phosphate and carbonate. The bone mineral analogue that best explains these variations in bone composition is octacalcium phosphate carbonate [Ca4 (PO4)2(HPO4)x(CO3)1-x,zH2O].     

Present prognosis in neonatal meningitis

A retrospective study of neonatal meningitis for a period of 6 years (1970 to 1975) is described. It was found that though the survival rate had increased since the introduction of the aminoglycosides, it was at the expense of major neurological sequelae in the survivors. It is suggested that breast feeding of all infants in the first few days of life will reduce the incidence of neonatatl meningitis. It is recommended that pooled human breast milk should not be heat-sterilized as this destroys anti-Escherichia coli immunoglobulin A.     

Reversal of pretreatment hypotension and control of hemorrhage in trauma patients by a simple device

The injection of a suspension of Walker 256 carcinoma cells into the carotid artery of rats produced a model of hematogenously spread cerebral metastases. Most animals died from massive extracerebral tumors of the head and jaw; brain tumors were present in only one-quarter. External carotid artery ligation prior to tumor inoculation did not increase the incidence of fatal brain tumor. When cyclophosphamide, 15 mg/kg, was injected as a single dose on the fourteenth day after tumor inoculation, most of the extracerebral tumor disappeared. Fifty percent of the animals so treated were cured of tumor, but 90% of the remainder died of large intracerebral tumors. Severe cytopathic changes resulting from cyclophosphamide were present in extracerebral or choroid plexus tumors but were mild or nonexistent in intracerebral tumors. These selective effects of cyclophosphamide suggest that water-soluble agents are less effective against tumor in the brain than against extracerebral tumors despite the fact that metastatic tumor breaks down the blood-brain barrier.     

Amyloid in polypeptide hormone-producing tumors

The hormone content of 72 endocrine tumors was determined by immunofluorescence and their amyloid content was investigated. Seventeen of the 72 tumors contained amyloid. Amyloid was frequently found in tumors producing calcitonin, insulin, or growth hormone, but was rarely found in other tumors. Thus, there is a relationship between the occurrence of amyloid in an endocrine tumor and the type of hormone it produces. The reason for this is not known, but there is evidence that the amyloid fibrils contain proteins related to the hormone produced by the tumors.     

Detecting complications of direct arterial surgery: the role of intraoperative arteriography

Intraoperative arteriography was carried out using a specially constructed operating table and long x-ray film changer that permitted rapid serial exposure of the arterial reconstruction and the distal arteries. During a ten-year period, this method was applied in 1,810 arterial reconstructions, with technical problems being detected in 82 (4.6%) of these patients. The incidence of problems was highest in patients undergoing endarterectomy, where 16.7% of the patients were found to have either residual debris in the cleared segment or areas of stenosis. When bypass grafts were used, technical problems were found in 2.2% of patients and included embolism or thrombosis, graft torsion in vein grafts, stenosis of the distal anastomosis, and the creation of an intimal flap. In the entire series, five patients needed reoperation in the early postoperative period. In three of these, the operative arteriograms had been initially misread.     

Transtympanic facial nerve paralysis

In order to ascertain the immediate histopathological changes of rat brain following experimental surgical injury, fragments of left parietal cortex were obtained through craniotomy and fixed by immersion. Next, the animals were killed by perfusion with the same fixative used for the respective biopsy. Five groups of rats were tested, each for one different fixative. Dark neurons were by far the most prominent feature in surgically traumatized tissue, following both immersion and perfusion with all five fluids. They were morphologically identical at both sites, and fixatives with widely different chemical composition, e.g. Bouin's fluid and buffered glutaraldehyde, had no influence on their aspect. It is suggested that shrunken neurons are not to be interpreted systematically as artefacts, but also represent a form of short-latency cellular reaction to injury.     

Placental diffusing capacities at varied carbon monoxide tensions

To test the hypothesis that carbon monoxide transfer across the placenta is, in part, a facilitated process, we have looked for evidence of saturation kinetics for carbon monoxide. In eight pregnant ewes, fetal to maternal carbon monoxide transfer was examined in a preparation in which the fetal side of the placenta was perfused with blood. The carboxyhemoglobin concentrations on the fetal side of the placenta were varied from 4.8 to 70% in 23 measurements. At increased carbon monoxide tensions, the transfer from fetus to mother always decreased. The slope of log rate of carbon monoxide transfer vs. log partial pressure gradient across the placenta was significantly different from 1. Placental membrane diffusing capacity was calculated separately from total placental diffusing capacity which includes hemoglobin reaction rates and erythrocyte membrane diffusion. Placental membrane diffusing capacity decreased at increased carbon monoxide tensions. Placental permeability for urea did not change with increasing carbon monoxide tensions. These results are consistent with the hypothesis that carbon monoxide diffusion in the placenta is, in part, carrier mediated.