Effect of Zr:Mo ratio on 99mTc generator performance based on zirconium molybdate gels.

Zirconium molybdate gels have shown to be viable alternatives for preparation of 99mTc generators using 99Mo produced by neutron activation. The aim of this work was to investigate the effect of the Zr:Mo molar ratio on the gel chemical structure and correlate it with the elution efficiency. A series of gels were prepared at Zr:Mo molar ratios from 0.5:1 to 2.3:1 and characterized by TGA, IR, XRD and UV. It was found that the variation of Zr:Mo ratio produces different polymolybdate arrangements on the octahedral units around to the zirconia which is mainly influenced by the water content. When the matrix molybdenum concentration was increased a lesser amount of water was found and the elution efficiencies were increased. However high elution efficiencies produce higher 99Mo breakthrough values. The gel formulation appears thus to be a compromise between the elution efficiency and the molybdenum breakthrough. The chemical-physical properties of these gels are presented and discussed.     

Application of factor VII-Sepharose affinity chromatography in the purification of human tissue factor apoprotein

Coagulation factor VII covalently coupled to Sepharose proved to be an effective binding ligand for human tissue factor apoprotein, the specific cofactor of factor VII for the activation of factor X and IX. This interaction is completely calcium-dependent and the calcium ions cannot be replaced by magnesium or barium ions. The binding of the apoprotein to immobilized factor VII seems to be independent of the presence of phospholipid. When factor VII-Sepharose column chromatography is combined with a mild extraction procedure, tissue factor apoprotein could be purified approximately 40,000-fold from an acetone powder of human brain. SDS-PAA gel electrophoresis revealed that with this simple purification scheme human tissue factor apoprotein can be purified to apparent homogeneity and that the apoprotein migrates at a molecular weight of 47,000. The isolated human protein is heterogeneously glycosylated; the two different forms of the apoprotein function as cofactor of factor VII in the activation of both factor X and factor IX.     

Effect of compression of spinal cord on brain rhythms

Electroencephalographic changes were studied in anaesthetised rats, subjecting them to the mechanical compression of spinal cord. The EEG waves that were studied-Alpha, Theta, and Delta. The changes in these waves and shift from one pattern to another after the compression of the spinal cord at the Lumbar level. These waves were subjected Fourier analysis. The results show remarkable changes in wave patterns and a shift in the dominating wave pattern. With 50% compression the EEG showed a slight increase in the amplitude in all three wave forms-- with Delta wave pattern being more dominant. At 100% compression there is a marked decrease in the Delta amplitude compared to normal. We tried to observe the changes in activity of the brain--the effects of spinal lesion and its relationship with tonic activity changes in EEG.     

High-efficiency stable gene transfection using chloroquine-treated Chinese hamster ovary cells

We describe a highly efficient stable gene transfection procedure for Chinese hamster ovary (CHO) cells using a modification of the calcium phosphate-DNA coprecipitation method. We have found that treatment of CHO cells with chloroquine increases the efficiency of gene transfer by up to 20-fold (from approx. 0.01% to approx. 0.2%) when transfection is done using the pSV2-neo plasmid. The optimized transfection procedure requires that CHO cells to be incubated with calcium phosphate-DNA coprecipitate and chloroquine (100 µM) for a total of 16 h. By using high-molecular-weight human genomic DNA as a DNA source for transfection, we show that this procedure is equally efficient for stably transferring a much larger gene, such as the 49-kb human hypoxanthine phosphoribosyltransferase gene.     

Botulinum versus tetanus neurotoxins: Why is botulinum neurotoxin but not tetanus neurotoxin a food poison?

Botulinum and tetanus neurotoxins, produced by Clostridium botulinum and Clostridium tetani, respectively, are the most poisonous poisons known to mankind. Although botulinum and tetanus neurotoxins share several characteristics, such as similar mol. wts, similar macrostructure, virtually identical mode of action, and a strong amino acid sequence homology, the two neurotoxins differ in one very significant way; only botulinum neurotoxin is a food poison. Factors responsible for the food poisoning potential of botulinum neurotoxins seem to be a group of complexing proteins that are also produced by C. botulinum, and are known to associate with the neurotoxin. Translation products of nucleotide sequences upstream to the neurotoxin genes of serotypes A, B, C, D, E and F botulinum neurotoxin reveal the location of genes for one of the complexing proteins that could be transcribed as polycistronic mRNA to include neurotoxin sequences. No such protein seems to be present in C. tetani, suggesting that the lack of complexing proteins might be responsible for tetanus not being a food poison.     

The epidemiology of psychosis: the Suffolk County Mental Health Project.

This article describes the rationale, aims, and methodology of an epidemiological study of psychosis being conducted in Suffolk County, New York. A sample of first-admission patients is drawn from 10 inpatient and 25 outpatient facilities. Diagnostic psychosocial interviews are conducted shortly after admission to treatment, and at 6- and 24-month followup. Consensus diagnoses are made after each interview. Demographic and clinical background characteristics of the first 250 subjects enrolled over a 2-year period are presented here. The response rate was 76 percent. Based on the initial interview, 75 percent of subjects received a diagnosis involving psychosis. The three most common diagnoses were schizophrenia, bipolar disorder with psychotic features, and major depression with psychotic features. Among subjects with psychosis, 58 percent of males and 29 percent of females had a history of substance abuse/dependence. Gender differences were found on several background and clinical characteristics. Males were somewhat younger, less likely to have ever married, and had less education. Although the median length of hospitalization was the same for females and males (27 days), females were more likely to be hospitalized within 1 month of the occurrence of their first psychotic symptom (60% of females compared to 37% of males). Subjects with schizophrenia-related disorders were significantly more impaired on an assessment of negative symptoms than were affectively ill subjects, but clinical ratings of depression were not significantly different across diagnostic groups.     

Alterations in the pattern of collagen deposition may contribute to the deterioration of systolic function in hypertensive patients with heart failure.

OBJECTIVES: We sought to assess the distribution of collagen deposits and collagen degradation in hypertensive patients with either systolic heart failure (SHF) or diastolic heart failure (DHF). BACKGROUND: Increased collagen synthesis and deposition have been described in the myocardium of heart failure (HF) hypertensive patients. METHODS: We studied 39 HF hypertensive patients subdivided into two groups: 16 with SHF and 23 with DHF. Endomyocardial biopsies were performed to quantify mysial (i.e., perimysial plus endomysial) and perivascular and scar-related collagen volume fraction (CVF). Matrix metalloproteinase (MMP)-1 and its tissue inhibitor matrix metalloproteinase (TIMP)-1 were analyzed in cardiac samples by Western blot and immunohistochemistry, and in blood samples by enzyme-linked immunosorbent assay. RESULTS: Mysial CVF was lower in SHF hypertensive patients than in normotensive (p < 0.05) and DHF hypertensive patients (p < 0.01). Perivascular and scar-related CVF was higher (p < 0.05) in the two groups of hypertensive patients than in normotensive subjects, and in SHF hypertensive compared with DHF hypertensive patients. The MMP-1:TIMP-1 ratio was increased (p < 0.05) in tissue and serum samples from the SHF hypertensive group compared with the other two groups of subjects. The MMP-1 expression was increased (p < 0.01) in the interstitium and cardiomyocytes of SHF hypertensive patients compared with DHF hypertensive and normotensive subjects. The serum MMP-1:TIMP-1 ratio was inversely correlated with ejection fraction (r = -0.510, p < 0.001) and directly correlated with left ventricular end-diastolic diameter (r = 0.549, p < 0.001) in all subjects. CONCLUSIONS: These findings show that the pattern of collagen deposits and the balance of the MMP-1/TIMP-1 system are different in the myocardium of SHF and DHF hypertensive patients. It is proposed that excessive degradation of mysial collagen may be related to the compromise of systolic function in HF hypertensive patients.