Do Eye Hospitals Have a Role in Our Future?

Eye hospitals, originally founded to care for the poor, have developed into academic centers and tertiary "hospitals of last resort." Inexorable economic pressures, especially price competition, are likely to close many of them, particularly those which are marginal in quality or management. Survival of the remainder may further depend on their ability to adapt to a rapidly changing environment and to fulfill, better than anyone else, the special mission of basic and clinical research and training. Society must be convinced that some of these complex, highly differentiated, relatively expensive eye hospitals are significant national resources, serve the public welfare, and are worth preserving.     

Long-term metabolic effects of truncal vagotomy and gastrojejunostomy for chronic duodenal ulcer

In a review of 305 consecutive patients who had undergone truncal vagotomy and gastrojejunostomy for duodenal ulceration 5-15 (mean 10.5) years before, symptomatic and metabolic sequelae were related to a dietary survey in 109 patients. The incidence of post vagotomy symptoms was related to the incidence of weight loss and reduced dietary energy intake. The dietary survey did not show any trends in the incidence of weight loss since operation. Biochemical steatorrhoea occurred in 48% of 96 patients, but this was not related to dietary fat intake, or to weight loss unless diarrhoea was also present. Anaemia was noted in 13% of patients, but the incidence was not related to dietary survey, age, symptoms or post-vagotomy gastric acid output.     

Catheter obstruction during prolonged parenteral alimentation. Are lipids responsible?

Catheter obstruction is a serious incident during prolonged parenteral nutrition (PN). This retrospective study was carried out in order to compare the frequencies of catheter obstruction with nutritive mixtures in bags according to whether or not lipids were mixed with the entire 24 h nutritional supply (Group I, n=33) or infused separately (Group II, n=30). Our results show that obstructions are significantly more frequent in Group I (11 13 ) than in group 2 (3 10 ), appearing within a mean interval of 29 days after inserting the catheter. The global percentages of patients undergoing cyclic PN were the same in both patient groups. In group I, however, the percentage of patients on cyclic PN was significantly higher for the obstructed catheters (100%) than for the unobstructed catheters (59%). In conclusion, the mixture of lipids with the remainder of the nutrients in the conditions of this study is the prime cause of catheter obstruction, although the exact mechanism is not elucidated. The role of cyclic PN appears to be accessory.     

The binding of somatostatin to rat synaptosomal membranes: effects of detergent solubilisation and of bacitracin

Specific high and low affinity binding sites for somatostatin have been demonstrated in rat brain synaptosomal membranes using 125I [Tyr"] somatostatin tracer. When incubations were carried out in the presence of low concentrations of bacitracin (0.01% w/v), a 66% increase in association constant of the high affinity binding site to Ka = 1.71 X 10(10) M-1 and a 70% increase in the Ka of the low affinity site to 0.034 X 10(10) M-1 were observed; a similar (50%) increase in the binding capacity of the low affinity site but no increase in the binding capacity of the high affinity site was seen. These results may indicate a direct effect of bacitracin on the membrane that is distinct from its effect as an inhibitor of tracer degradation. The somatostatin-binding capacity of the membranes was solubilised by treatment with Triton X-100 and the apparent molecular weight of the receptor-ligand-detergent micelle complex was estimated by gel filtration to be approximately 250,000.     

Transplantation of Pacinian corpuscles of the rat into the brain

Summary In adult inbred rats of the AVN strain, branches of the crural interosseous nerve were dissected out from donors and transplanted into the brain of recipients, together with a cluster of Pacinian corpuscles, (either into a suction cavity or the cerebral cortex) into a slit 1–2 mm deep. The grafts were fixed and processed for electron microscopy 10 days to 6 months after the operation, and their ultrastructure was examined. Sporadic axons of small diameter grew into the nerve branches of some of the grafts from 11 days onward, and became myelinated during the 2nd month after the operation, but none of the transplanted Pacinian corpuscles became reinnervated. The corpuscles, however, survived denervation and grafting. Most of them retained a well-preserved inner core and an intact capsule, consisting of a normal complement of 29.2±1.0 (mean ±SE) capsular layers (n=8), as did the corpuscles previously examined after denervation in situ. Some of the corpuscles underwent degenerative changes, presumably due to a delayed or restricted revascularization. In this group of corpuscles, the inner core underwent disintegration and was gradually replaced by collagen fibrils, whereas the capsule remained preserved but the number of its layers eventually reduced by 40%. It is assumed that the lack of reinnervation of the grafted Pacinian corpuscles was due to the paucity of regenerating axons, and their failure to form correct projections along those Schwann cell columns connected with the corpuscles.     

Transient hypercalciuria after commencing total intravenous nutrition

A study of 28 patients receiving a standard regimen of total intravenous nutrition (I.V.N.) for periods of > 14 days has shown the transient development of hypercalciuria in 14 patients (50%). The peak incidence of hypercalciuria occurred in 11 patients (39%) after 1 week of I.V.N. and hypercalciuria persisted for 1–4 weeks. In only one patient was hypercalciuria present at the end of the treatment period. Urine calcium (Ca) and nitrogen (N) excretion rates correlated significantly (r = 0.48 p<0.001) and urine N excretion varied from week to week in parallel with urine Ca excretion in the hypercalciuric group of patients. There was no significant difference in urine Ca excretion between 12 patients who received 3.75 mmol Ca/day and 16 patients who received 8.75 mmol Ca/day. It is concluded that transient hypercalciuria may be related to increased protein catabolism and N excretion and that it probably does not indicate a major problem in mineral metabolism.     

Clinical implications of continuous measurement of energy expenditure in mechanically ventilated patients

Energy expenditure was monitored in 20 critically-ill mechanically ventilated patients using the Siemens-Elema Oxygen Consumption Calculator (OCC 980). Energy expenditure was measured continuously over the 24-h period in all patients (altogether, over 2500 patient hours; range 48-288 h). A predicted energy expenditure was calculated for each patient from standard tables for basal metabolic rates modified according to previously published reports on the influence of trauma, infection and elevated body temperature. For all patients combined, the agreement between the predicted and the measured energy expenditure was good. However, in individual patients the measured energy expenditure varied between 48 and 148% of the predicted value. The measured energy expenditure in surviving traumatized and/or septic patients correlated well (95-100%) with the predicted value at the time when weaning off the ventilator could be initiated. On the first day of measurements, the energy expenditure (in % of the predicted value) in the six patients who later died was significantly lower than in surviving patients (84 +/- 6 vs 107 +/- 2%; p < 0.01). Over a 24-h period, energy expenditure, defined as the value noted during a stable 30-40-min period of measurement, varied between 12 and 50% in the individual patients. This study shows that energy expenditure cannot be accurately predicted in the individual patient, that an energy expenditure below predicted values appears to be indicative of a poor prognosis and that short periods of energy expenditure monitoring may fail to reflect 24-h conditions.     

Creaming and plasma clearance rate of intravenous fat emulsion in critically ill patients

Intravenous fat emulsion incubated with serum or plasma in vitro may result in the aggregation of fat (creaming). Twenty critically ill patients were tested for in vitro creaming of the fat emulsion Intralipid. An intravenous fat tolerance test was used to determine the plasma clearance rate of Intralipid in each patient. Eleven patients (55%) were found to be creamers. These patients had a higher mean plasma clearance rate of Intralipid than non-creamers (5.73 +/- 0.56 vs. 2.77 +/- 0.37% per min; p < 0.001); however, the rates of both groups were within the range reported in normal healthy subjects. Mean C-reactive protein concentration was significantly higher (p < 0.01), and albumin levels were lower (p < 0.01) in creamers compared to non-creamers. Ionized calcium levels did not differ between the two groups. The results of this study indicate that in vitro creaming is common in acutely ill patients. The clinical significance of creaming is probably minimal since creamers tolerated 50 to 100 g/day of intravenous fat emulsion while receiving total parenteral nutrition. Creaming was uncommon when the fat was mixed with blood in vitro.