Vasodilator agents and supracollicular transection fail to inhibit cortical spreading depression in the cat

It remains an open question as to whether cortical spreading depression (CSD) is the pathophysiological correlate of the neurological symptoms in migraine with aura. In the experimental animal, CSD is an electrophysiological phenomenon mainly mediated via NMDA receptors. However, according to case reports in humans, visual aura in migraine can be alleviated by vasodilator substances, such as amyl nitrite and isoprenaline. There is also circumstantial evidence that brainstem nuclei (dorsal raphe nucleus and locus coeruleus) may play a pivotal role in the initiation of aura. In this study, CSD was elicited in alpha-chloralose anesthetized cats by cortical needle stab injury and monitored by means of laser Doppler flowmetry. Topical application of isoprenaline (0.1-1%) and amyl nitrite (0.05%) onto the exposed cortex had no effect on the elicitation or propagation of CSD. Also, after supracollicular transection, subsequent CSDs showed no differences in the speed of propagation and associated flow changes. We conclude from these data that--given CSD probably exists in humans during migraine--spreading neurological deficits during migraine aura are independent of brainstem influence and have a primarily neuronal rather than vascular mechanism of generation.     

Cardiovascular risk factors in normotensive and hypertensive Egyptians.

OBJECTIVES : To define the prevalence of cardiovascular risk factors and their relation to the level of blood pressure, in Egyptians. METHODS : Data were collected during the Egyptian National Hypertension project, a national hypertension survey in Egypt. During phase I of the survey, hypertensive (HT) patients were identified. In phase II, clinical and laboratory evaluations were made on HT and gender-matched normotensives (NT). A total of 2313 individuals were examined, 311 NT males, 443 NT females, 670 HT males and 889 HT females. RESULTS : The prevalence of obesity was 33 and 47% in hypertensive men and women, respectively. After adjusting for age, HT men had significantly higher heart rate, total cholesterol (TC), triglycerides (TG), fasting blood sugar (FBS), post-prandial blood sugar (PBS), body mass index and waist/hip (W/H) ratio than their NT counterparts. In addition, HT women had higher low-density lipoprotein cholesterol (LDL-C). The prevalence of elevated LDL-C and FBS increased with age. The prevalence of hypertriglyceridemia, elevated FBS and obesity rose with increasing level of blood pressure (BP). From the 25-34 to the 55-64 age group, the percentage of hypertensives with > or = 2 risk factors rose from 42.9 to 60.6% in men, and from 9.4 to 46.2% in women. All risk factors were more prevalent in urban populations. CONCLUSION : This is one of the few reports on the prevalence of cardiovascular risk factors in a developing country. Risk factors cluster with rising level of BP and with ageing. Obesity is very prevalent, particularly in hypertensive Egyptian women. Health efforts directed at the prevention and treatment of obesity should be a high priority.     

Dichotic-listening task performance of mildly mentally retarded and nonretarded individuals

An investigation of hemispheric lateralization of mildly mentally retarded individuals was undertaken employing the dichotic-listening paradigm. Exclusively right-handed, right-eyed, and right-footed equal-CA, equal-MA, and mildly retarded subjects were required to recognize and reject dichotic presentation-probe stimulus combinations of words and tones correctly. The dichotic presentation-probe stimulus technique was employed to minimize the influence of memory and to equate methodologically for the handling of the verbal (spoken digits) and nonverbal (complex tones) stimuli. The findings revealed a pattern of dichotic performance that was similar for the three subject groups. A right-ear advantage was obtained for the verbal stimuli; and a left-ear advantage, for the nonverbal stimuli. Performance accuracy, however, was significantly poorer for the mildly retarded subjects relative to the nonretarded subjects. Structural vs. control process differences in the information-processing system were discussed.     

Ankle: surface coil MR imaging at 1.5 T

High-field surface coil magnetic resonance (MR) images were obtained of 12 ankles: two from healthy volunteers, seven from patients, and three from fresh cadavers. The cadaver ankles were sectioned in the coronal, sagittal, and axial planes for direct comparison with the MR images. Plain film confirmation of pathologic conditions was obtained in all patients, and five underwent arthroscopy or surgery, or both. MR imaging provided excellent delineation of ligaments and cartilaginous structures in all cases.     

Platelet transfusion from donors mismatched for crossreactive HLA antigens

Increments in platelet counts following the transfusion of platelets mismatched for crossreactive antigens were evaluated in 67 patients with broad alloimmunization to HLA antigens. The corrected increments following 100 HLA, A-matched and B1U- or B2U-matched transfusions were compared with the increments following 307 B1X- or B2X-matched transfusions. HLA-A3 platelets were tolerated poorly by A1 and A11 recipients, as were A1 and A11 by A3 recipients, B17 and BW21 by recipients in the B7 crossreactive group, B5 by B15 and B17 recipients, and B27 by recipients in the B5 crossreactive group. B12 and BW21, and B8 and B14 platelets were not tolerated bidirectionally. Antigens associated with good increments included A28 in A2 recipients, B18 and BW16 (C match) in recipients in the B5 crossreactive group, B5 in B18 recipients, BW22 and B7 in recipients in the B7 crossreactive group. A1 and A11 were transfused successfully bidirectionally. These observations suggest that some private antigens within crossreactive groups are more immunogenic than others and support the observation of others than B17 and BW21 are not in the B5 crossreactive group.     

Fragmented IgG for post-exposure prophylaxis of type A hepatitis

To determine whether fragmentation of IgG in immune serum globulin (ISG) preparations has an adverse effect upon protection against type A hepatitis, three materials were given to household contacts of icteric cases: (1) human albumin as a placebo; (2) normal ISG containing intact IgG; and (3) ISG from the same lot but containing IgG deliberately fragmented with fibrinolysin. Attack rates per 100 children were 4.9, 2.8, and 2.3, respectively. IgG fragmentation, therefore, had no adverse effect on overall level of protection. In addition, IgG fragmentation produced a statistically significant reduction in secondary attack rate when given as late as six days prior to expected onset (as judged from the placebo group); ISG with intact IgG had to be given 16 days or more prior to expected onset to achieve a comparably significant reduction. This result suggests that fragmentation may be advantageous for ISG preparations intended for post-exposure prophylaxis of viral diseases.     

Hypergammaglobulinemia can be associated with a positive direct antiglobulin test, a nonreactive eluate, and no evidence of hemolysis

To determine the cause of a positive direct antiglobulin test (DAT), blood banks routinely perform serologic tests on eluates prepared from DAT-positive red cells. Negative eluates traditionally have been suspected to be associated with drug reactions. This report confirms that the most frequent cause of a positive DAT and a nonreactive eluate is hypergammaglobulinemia. The results of 74 patient samples with positive DATs were analyzed retrospectively. Eluates prepared from the red cells of 54 patients (72.9%) reacted; eluates from 20 patients (27.1%) did not react. This latter group had identical serologic and clinical findings, suggesting that they made up a homogeneous group. In particular, the patients had a positive DAT, a negative indirect antiglobulin test, and a negative eluate; an increased serum concentration of IgG; and no evidence of hemolysis. In a subsequent study, DATs were performed prospectively on red cells from 44 consecutive patients with elevated serum IgG levels. The serum IgG concentration was highest in the three patients whose red cells had a positive DAT. The DAT also became positive in two patients treated with high-dose intravenous gammaglobulin (IV IgG). These studies indicate that a negative eluate from red cells with a positive DAT, a common serologic finding, is often caused by hypergammaglobulinemia. The authors postulate that IgG binds nonspecifically to the red cells because of the hypergammaglobulinemia.     

Donor screening for antibody to hepatitis B core antigen and hepatitis B virus infection in transfusion recipients

BACKGROUND: Testing for antibody to hepatitis B core antigen (anti-HBc) as a surrogate for hepatitis C viremia is no longer needed for blood donor screening. Currently, the important question is how much its use supplements hepatitis B surface antigen (HBsAg) donor screening in preventing transfusion-transmitted hepatitis B virus (HBV) infection. STUDY DESIGN AND METHODS: In a study conducted in the 1970s, 64 blood donors were associated with 15 cases of HBV (1.0%) in 1533 transfusion recipients. Sera from 61 donors at donation and 29 follow-up visits were available for present-day assays for HBsAg, HBV DNA, anti-HBc, and antibody to HBsAg (anti-HBs). RESULTS: HBsAg was found in four previously negative blood donors; HBV DNA was limited to three of these four. Anti-HBc was detected in six HBsAg-negative donors. Two other donors were negative in all assays at donation, but positive for anti- HBc and anti-HBs 2 to 4 months later. The remaining donors were negative for all HBV markers, which left five recipient cases unexplained. No HBV transmission was observed when anti-HBs sample-to- negative control values were > or = 10. CONCLUSION: Some 33 to 50 percent of cases of hepatitis B that could be transmitted by transfusion of blood from HBsAg-negative donors are prevented by anti- HBc screening. Anti-HBc-positive donors unequivocally positive for anti- HBs should be considered noninfectious for HBV and should be allowed to donate. Anti-HBc screening of paid plasmapheresis donors, supplemented by anti-HBs testing, would reduce the amount of HBV to be processed by virus inactivation and increase the content of anti-HBs in plasma pools.