Migration of lymphocytes sensitized against syngeneic and allogeneic spinal cord after infusion into susceptible and resistant syngeneic and semi-allogeneic hosts

Lymphocytes from rats that had been sensitized against spinal cord were infused into unsensitized hosts, and the ability of cells subsequently recovered from the thoracic duct lymph of these recipients to mount anti-neural responses was tested. Lymph from normal recipients frequently contained reactive lymphocytes during the 4 days following infusion of sensitized cells, whereas cells that had been recovered from transfused rats, resistant to encephalomyelitis as a result of neonatal treatment, were almost invariably benefit of activity. If lymphocytes reactive against allogeneic neural cells were passaged through F1 hybrids of the lymphocyte and sensitizing allogeneic tissue strains, loss or retention of their ability to attack allogeneic neural cells was determined by the method of sensitization of the original lymphocyte donor.

Specific inhibition of anti-self reactivity following exposure of neonatal rats to lymphocytes with anti-neural activity

Not only did newborn rats prove to be resistant to the adoptive transfer of responses against central nervous system tissues following the injection of lymphocytes from rats sensitized against syngeneic spinal cord, but such recipients were also subsequently resistant as adults to the active induction of an immune response following challenge with syngeneic cord. This resistance to active immunization against syngeneic spinal cord as adults was associated with the absence of lymphocytes with anti-neural activity and with the appearance of cells able to suppress such activity, after challenge. Interference by the lymphocytes of resistant rats with anti-neural responses was restricted to those responses directed against syngeneic neural cells.

Reactivity of neuro-antigen-sensitized lymphocytes against syngeneic, allogeneic and tolerated allogeneic neural tissue

Lymphocytes reactive against cultured cerebellar cells were collected from rats that had been sensitized against a variety of preparations. While cells with in vitro reactivity were invariably present in lymph from rats which were to develop encephalomyelitis, the reverse did not apply. Challenge with either neural or non-neural allogeneic tissue sensitized effectively against allogeneic neural tissue. Challenge of homograft-tolerant rats with either syngeneic or tolerated allogeneic spinal cord sensitized against neural tissues of tolerated strain.

New system for single-needle dialysis

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Prophylactic disopysramide: its clinical effects related to plasma concentration in myocardial infarction

Sixty-three patients, fifty-two with acute myocardial infarction and eleven with ischaemic heart disease or non-cardiac chest pain, were given either disopyramide phosphate or placebo, orally, in a randomized double-blind study. Thirty-two patients on disopyramide (twenty-six with acute myocardial infarction) received an initial dose of 300 mg followed by 150 mg six-hourly for 3 days.

There was a reduction in the number of patients with cardiac dysrhythmias on the first 3 days following infarction in subjects taking disopyramide as compared with controls. This reduction was not statistically significant. There was a significant reduction in the mean ectopic count per hour in patients taking disopyramide compared with those taking placebo on the second day only (p < 0.005). Urinary retention, dry mouth and jaundice were recorded more frequently in the test group.

There were wide ranges of pre-dose plasma concentrations on all 3 days. (Day 1: 1.3 to 7.7 μg per ml. Day 2: 2.5 to 8.9 μg/ml and Day 3: 2.5 to 11.5 μg per ml). The mean plasma concentration of disopyramide was higher but not significantly so, in the treatment group without evidence of dysrhythmias than those with dysrhythmias (3.8 ± S.D. 1.5 μg/ml and 3.0 ± 0.8 μg/ml respectively). The mean plasma level in patients who required anti-emetic therapy was significantly lower than those who did not (2.8 ± 0.8 μg/ml and 3.8 ± 1.9 μg/ml respectively, p < 0.025).

The wide range of plasma levels observed is probably due in part to irregular absorption with vomiting after myocardial infarction. If disopyramide is to be used prophylactically following myocardial infarction, a therapeutic plasma level will be achieved quickly in all cases only by giving an intravenous starting dose.

The "bull's-eye" falciform ligament: a sonographic finding of portal hypertension

The umbilical vein may dilate as a collateral in portal venous hypertension and become visible within the echodense fat of the falciform ligament. The resulting "bull's-eye" appearance was visible in 5/47 (11%) of patients with cirrhosis secondary to alcohol abuse. It was not visualized in any patients with cholelithiasis who had no evidence of cirrhosis. When demonstrated by ultrasound, this finding should suggest portal venous hypertension.

Recognition of histocompatibility determinants controls reactivity of auto-sensitized lymphocytes against neural tissues

Thoracic duct lymphocytes from rats sensitized against syngeneic spinal cord rapidly produce damage in cultures of syngeneic cerebellar cells but coexist indefintely with allogeneic cultures. Lymphocytes from donors that have been sensitized against allogeneic spinal cord attack cultures of syngeneic and specific allogeneic cerebellum but not cells from rats of a third, unrelated strain.

Oxidative metabolism of 4-aminobutyrate by rat brain mitochondria: inhibition by branched-chain fatty acid

The oxidation of 4-aminobutyric acid (GABA) by nonsynaptosomal mitochondria isolated from rat forebrain and the inhibition of this metabolism by the branched-chain fatty acids 2-methyl-2-ethyl caproate (MEC) and 2.2-dimethyl valerate (DMV) were studied. The rate of GABA oxidation, as measured by O2 uptake, was determined in medium containing either 5 or 100 mM-[K+]. The apparent Km for GABA was 1.16 +/- 0.19 mM and the Vmax in state 3 was 23.8 +/- 5.5 ng-atoms O2 x min-1 x mg protein-1 in 5 m M-[K+]. In a medium with 100 mM-[K+] the apparent Km was 1.11 +/- 0.17 mM and Vmax was 47.4 +/- 5.7 ng-atoms O2 x min-1 x mg protein-1. The Ki for MEC was determined to be 0.58 +/- 0.24 or 0.32 +/- 0.08 mM, in 5 or 100 mM-[K+], respectively. For DMV, the Ki was 0.28 +/- 0.05 or 0.34 +/- 0.06 mM, in 5 or 100 mM-[K+] medium, respectively. The O2 uptake of the mitochondria in the presence of GABA was coupled to the formation of glutamate and aspartate; the ratio of oxygen uptake to the rate of amino acid formation was close to the theoretical value of 3. Neither the [K+] nor any of the above inhibitors had any effect on this ratio. The metabolism of exogenous succinic semialdehyde (SSA) by these same mitochondria was also examined. The Vmax for utilization of oxygen in the presence of SSA was much greater than that found with exogenously added GABA, indicating that the capacity for GABA oxidation by these mitochondria is not limited by SSA dehydrogenase. In addition, the branched-chain fatty acids did not inhibit the metabolism of exogenously added SSA. Thus, the inhibitors examined apparently act by competitively inhibiting the GABA transaminase system of the mitochondria.

Warfarin skin necrosis. The role of factor VII

Necrosis of cutaneous and subcutaneous tissue is a rare complication of therapy of with oral anticoagulants, and is related to the use of loading-dose regimes. Three cases are reported, and demonstrate that the principal histopathological feature is thrombosis within the subcutaneous vasculature. The effect of large doses of anticoagulant on the levels of the vitamin K dependent clotting factors provides a satisfactory model for the temporal sequence of events in this syndrome. The occurrence of intravascular thrombosis with low or absent levels of Factor VII indicates that the intrinsic clotting system is of primary importance in venous thrombosis. This complication of anticoagulant therapy is not seen if loading-dose regimes are avoided.

A deterministic model for measles

A deterministic model of recurrent epidemics is constructed using a non linear relationship between infection rate and number of contacts. Epidemic waves which are not damped are predicted and a relationship between community size and the period of recurrence is established. A possible explanation of measles outbreaks is suggested.

Gutta-percha points of apicoectomy. To push or to pull?

A gutta-percha root-filling point placed during apicoectomy may be condensed by the application of pressure to its coronal end or tension to its apical end. Scanning electron microscopy clearly demonstrates the effect that these techniques have on the adaptation of the root filling to the canal. The pressure method would appear to produce the more satisfactory result.

Self-concept and psychological adjustment differences between self-identified male transsexuals and male homosexuals

Self-concept and adjustment data from anatomical males seeking sexual reassignment surgery were compared with that from a male homosexual group. Findings indicated that the homosexual group had a better self-image and was better adjusted than the sex change group. Other findings are presented that reinforce the view that the norm violations in homosexuality and transsexualism do not necessarily imply serious character damage.