Indium-111 labeled platelet deposition following transfemoral angiography

The incidence of thromboembolitic events in patients undergoing transfemoral angiography was examined using indium-111 labeled platelets. Twenty-seven patients received approximately 300 muCi of autologous labeled platelets at least 3 hours before angiography and were scanned with a gamma camera immediately before and after angiography. All patients were free of clinically obvious complications in the 1-2 day period after angiography. Our results showed evidence of platelet deposition at 21 sites other than the puncture site in 12 (44%) patients. Most platelet deposition (54%) occurred along the region between the puncture site and the aortic bifurcation; 24% occurred at sites not traversed by the catheter. At the puncture site itself, there was substantial platelet uptake in 44% of patients. This study indicates the need for further work in determining the most suitable catheter material and in assessing the efficacy of other measures such as anticoagulant or antiplatelet therapy.     

Long-term use of antecubital veins for plasma exchange. The Canadian Cooperative Multiple Sclerosis Study Group

True or sham plasma exchange was done weekly for 20 weeks in patients in two of the randomization groups in a prospective, blind clinical trial of experimental treatments for multiple sclerosis. Because patients could be randomized to receive sham plasma exchange and placebo medications, it was decided when the trial was designed that the use of fistulae, arteriovenous shunts, venous cutdowns, or other aggressive forms of venous access would not be permitted for any patient. Accordingly, patients judged to have inadequate superficial antecubital veins were ineligible for the trial. To date, only 13 (4.4%) of 294 patients considered for entry into the trial have been rejected on these grounds. In only 4 of the 93 patients undergoing exchange was it necessary to discontinue plasma exchange because of inadequate venous access. In 79.3 percent of the 1207 exchanges done in these patients, there were no problems of any kind with venous access. In 5.4 percent of these 1207 exchanges, it was necessary to terminate the procedure prematurely because of difficulties with patients' veins. Thus, the great majority of patients free of serious systemic illness (other than chronic progressive multiple sclerosis) can undergo weekly plasma exchange for up to 20 weeks using superficial antecubital veins without the need to resort to more invasive methods of venous access.     

The Methylazoxymethanol Acetate (MAM-E17) Rat Model: Molecular and Functional Effects in the Hippocampus

Administration of the DNA-alkylating agent methylazoxymethanol acetate (MAM) on embryonic day 17 (E17) produces behavioral and anatomical brain abnormalities, which model some aspects of schizophrenia. This has lead to the premise that MAM rats are a neurodevelopmental model for schizophrenia. However, the underlying molecular pathways affected in this model have not been elucidated. In this study, we investigated the molecular phenotype of adult MAM rats by focusing on the frontal cortex and hippocampal areas, as these are known to be affected in schizophrenia. Proteomic and metabonomic analyses showed that the MAM treatment on E17 resulted primarily in deficits in hippocampal glutamatergic neurotransmission, as seen in some schizophrenia patients. Most importantly, these results were consistent with our finding of functional deficits in glutamatergic neurotransmission, as identified using electrophysiological recordings. Thus, this study provides the first molecular evidence, combined with functional validation, that the MAM-E17 rat model reproduces hippocampal deficits relevant to the pathology of schizophrenia.     

Statistical significance of sequential firing patterns in multi-neuronal spike trains

Sequential firings with fixed time delays are frequently observed in simultaneous recordings from multiple neurons. Such temporal patterns are potentially indicative of underlying microcircuits and it is important to know when a repeatedly occurring pattern is statistically significant. These sequences are typically identified through correlation counts. In this paper we present a method for assessing the significance of such correlations. We specify the null hypothesis in terms of a bound on the conditional probabilities that characterize the influence of one neuron on another. This method of testing significance is more general than the currently available methods since under our null hypothesis we do not assume that the spiking processes of different neurons are independent. The structure of our null hypothesis also allows us to rank order the detected patterns. We demonstrate our method on simulated spike trains.     

Radioprotection by copper and zinc complexes of 5-aminosalicylic acid: a preliminary study.

The effect of copper and zinc complexes of 5-aminosalicylic acid (hereafter referred to as Cu-5ASA and Zn-5ASA, respectively) against whole-body gamma radiation-induced cytotoxicity was studied in Swiss albino mice. Protection against lethal irradiation was evaluated from 30 day mouse survival (10 Gy) and endogenous spleen colony assay (11 Gy); and against sublethal dose (4 Gy) was assessed from gamma irradiation (RT)-induced formation of micronuclei in the mouse bone marrow 24 h postirradiation. Pretreatment with either Cu-5ASA (2.5-9 mg/kg) or Zn-5ASA (3.5-14 mg/kg) intraperitoneally (i.p.) delayed and reduced percentage mortality in mice exposed to 10 Gy RT. The doses 9 mg/kg for Cu-5ASA and 7 mg/kg for Zn-5ASA were found to be the most effective dose in preventing RT-induced weight loss and reducing percentage mortality. Both the drugs also caused an increase in the endogenous spleen colonies in mouse exposed to 11 Gy RT. At sublethal doses of RT, pretreatment with either Cu-5ASA or Zn-5ASA resulted in a significant decrease in the RT-induced micronucleated polychromatic erythrocytes and normochromatic erythrocytes (MPCEs and MNCEs) and an increase in the ratio of PCE to NCE (P/N), at 24 h postirradiation. These results show that both Cu-5ASA and Zn-5ASA are effective in protecting normal tissues against lethal and sublethal doses of RT. Further pretreatment with either Cu-5ASA or Zn-5ASA enhanced the survival of tumor-bearing mice (Ehrlich's ascites carcinoma) exposed to 7.5 Gy RT. In fact, both the complexes caused an increase in the mean and average survival times (MST and AST) when compared to the irradiated control, suggesting a synergetic effect of these drugs with radiation in causing cytotoxicity to the tumor cells. The data clearly indicate that both Cu-5ASA and Zn-5ASA significantly reduced the deleterious effect of radiation and hence could be useful agents in reducing the side effects of therapeutic radiation.