Effect of hemodilution on brain tissue during global ischemia

This study evaluates the effect of blood volume and hematocrit changes on brain tissue during temporary global ischemia. Normal saline was administered intravenously to 55 gerbils to achieve hypo-, normo-, and hypervolemic hemodilution and uniform 30% hematocrit reduction. Each group had unilateral carotid artery ligation and temporary (20 minute) contralateral carotid occlusion. After ten days or death, brains were harvested, preserved in formalin, sectioned in a manner which provided adequate samples of both cortex and hippocampus, and stained with H&E and luxol fast blue. They were then examined and staged microscopically for white and gray matter infarction, edema, and neuronal injury and loss. Histologic studies were performed in a randomized and blinded manner and were classified by one of four categories: normal, minimal, moderate, and severe changes. Three of ten (30%) controls survived ten days but had severe neuronal loss, minimal cerebral edema and a minimal to moderate number of white matter strokes. Survival was best in animals treated with hypovolemic hemodilution (43%). Other rates were: normovolemic (33%), controls (30%), and hypervolemic (8.3%). The degree of brain tissue damage was markedly less in the normovolemic group. In this model, normovolemic hemodilution followed by hypovolemic hemodilution offered the best overall cerebral protection during global ischemia.     

The influence of diabetes on free flap transfer: I. Flap survival and microvascular healing.

Although recent clinical case presentations suggest that diabetes does not predispose free tissue transfers to increased risk of failure, this remains an open question. The present study used a syngeneic rat strain (Lewis) for free groin flap transplantations between normal rats and streptozotocin-induced diabetic rats (2 months' duration of symptoms), to investigate the influence of diabetes on flap transfer. Flap survival at 1 week, vascular patency, flap histology and ultrastructure, and scanning electron microscopy of anastomotic sites and of corrosion casts of flap vasculature were used as bases for comparison. No differences were found in comparisons of flap survival between any groups of transfer combinations (normal flap onto normal recipient, diabetic flap onto normal recipient, normal flap onto diabetic recipient, and diabetic flap onto diabetic recipient); 100% success was achieved in each group. No differences were found in histology or corrosion casts. Transmission electron microscopy revealed a thickening of the capillary basement membrane in rat diabetic skin after only 8 weeks of symptoms. This ultrastructural finding is consistent with similar capillary basement membrane thickening seen in many other tissues of short- and long-term diabetic animals and humans. Re-endothelialization across the arterial anastomosis at 2 weeks postoperatively was significantly faster in normal versus diabetic animals (p less than 0.05). The predominantly negative findings of this study support the application of free flap transfers in diabetic patients. It is concluded that reconstructive efforts involving free tissue transfer may not be contraindicated in diabetic patients.     

Membrane lipids of B16 melanoma cells and heat-resistant variants

Membrane lipid composition and fluidity of a series of B16 melanoma cell variants with increased resistance to heat were analysed for changes within the lipid component that may contribute to the acquisition of heat resistance. Within one series of heat-resistant lines the cholesterol content of the cells decreased as their heat resistance increased. The most heat-resistant line, WH75, had 40 per cent less cholesterol than the parent line. No change in the composition of phospholipid fatty acids was found. An increased level of membrane fluidity in WH75 was demonstrated by electron paramagnetic resonance using 5- or 12-doxyl stearic acid. When challenged by heat the increase in membrane fluidity was similar for WH75 and for the parent line. Thus the increased heat resistance of the variants is probably not due to their ability to adapt to heat challenge by increasing membrane thermostability. The inverse relationship between heat resistance and cholesterol content was not demonstrated in two other series of heat-resistant variants. The cholesterol decrease, therefore, is not a universal response of cells as they acquire heat resistance.     

Opponensplasty by extensor indicis and flexor digitorum superficialis tendon transfer.

From 1977 to 1988, 166 patients with median nerve paralysis of varied aetiology underwent opponensplasty. In 50 of these the extensor indicis was used, and in 116 the flexor digitorum superficialis of the ring finger. An analysis of these hands showed that the EI opponensplasty was best in supple hands and FDS opponensplasty was more suitable for less pliable hands. There were fewer complications seen after FDS opponensplasty if the detachment of the donor tendon was done through a volar oblique incision rather than the conventional lateral incision.     

Water imbibition in the rat prostate during castration-induced regression

The present study was conducted to examine changes in water concentration in the ventral prostate of adult rats at different intervals following castration. The prostatic dry weight was obtained by drying the fresh prostate at 70 degrees C for at least 110 hr and the prostatic water content was calculated from its wet and dry weight. Under normal conditions, the prostatic water concentration ranges from 81.9 to 82.7% in uncastrated rats. The prostatic water concentration started to increase at 8 hr postcastration (83.1%) but this increase was not statistically significant. By 16 hr postcastration, the prostatic water concentration (83.8%) became significantly higher than that of the uncastrated animals. In rats of day 1 to day 10 postcastration, the prostate contained significantly more water (84.4%-84.7%) than those in uncastrated animals. By day 21 postcastration, the prostatic water concentration (81.5%) was not significantly different from that of uncastrated rats. Unlike the prostate, the skeletal muscle did not significantly change the water concentration following castration. The 51Cr-EDTA space in the prostate was not significantly different in rats before and after castration. These results indicate that water imbibition in the rat prostate is associated with an active period of prostatic regression and that the change in the 51Cr-EDTA space during prostatic regression is not the major cause of water imbibition in the tissue. Therefore, the present findings suggest that castration-induced water imbibition in the rat prostate is caused by an increase in the intracellular water space.     

Platelet and whole blood serotonin content in depressed inpatients: correlations with acute and life-time psychopathology.

Platelet or whole blood serotonin content did not differ significantly in patients with major depression compared to healthy controls, but within the patient group, platelet serotonin levels correlated negatively with severity of depression (r = -0.49, p = 0.007). Levels were 39% lower in patients who had made a suicide attempt compared to nonattempter patients (47.2 +/- 27.3 versus 77.6 +/- 41.7 ng/10(8) platelets, p = 0.04). Conversely, comorbid borderline personality disorder (85.3 +/- 41.5 ng/10(8) platelets) was associated with 31% greater platelet serotonin content than nonborderline patients (58.9 +/- 31.1 ng/10(8) platelets) and 27% greater than healthy controls (62.4 +/- 19.8 ng/10(8) platelets). A pronounced seasonal variation in whole blood and platelet serotonin content was found in both patients and controls, largely due to lower levels in summer. Excluding cases tested in the summer abolished the statistically significant differences in patients with and without comorbid borderline personality disorder (BPD). Nevertheless, BPD attempters had lower serotonin levels than BPD nonattempters but higher serotonin levels than non-BPD attempters. Current hostility and a life-time history of aggression were positively correlated with platelet serotonin content (r = 0.44, p = 0.04 and r = 0.41, p = 0.06). This study provides evidence for an association between lower platelet serotonin content and depression and suicidal behavior, and association of higher platelet serotonin content and comorbid borderline personality disorder and behavior traits such as aggressivity.