Light-induced electron spin polarization in the ground state of water-soluble copper porphyrins

Light-induced spin-polarized transient EPR spectra are reported for several water-soluble copper porphyrins. The spectra are assigned to the doublet ground state, with emissive spin polarization resulting from photoexcitation and subsequent electronic relaxation. In contrast to other systems for which polarization of a doublet ground state has been observed, the exchange interactions in the copper porphyrins are strong and the geometry is fixed. It is proposed that intersystem crossing from the photoexcited trip-doublet to the trip-quartet state can lead to net polarization of the spin system and that this polarization is maintained during electronic decay, possibly via charge-transfer and exciplex states. The intensity of the observed spin polarization is essentially independent of the molecular orientation in the external field, but is strongly dependent on the nature of the charged peripheral groups. Possible reasons for this behavior are discussed.     

Asbestos-related pericardial thickening detected by magnetic resonance imaging

Magnetic resonance imaging was performed in four male asbestos workers in whom the chest radiograph revealed pleural but not pulmonary or pericardial disease. Patients underwent thoracic multislice spin echo imaging, with measurement of left and right ventricular volumes at end-diastole and end-systole, and a study of the flow in the superior vena cava as an indirect measure to the filling of the right ventricle. Patients also underwent respiratory function tests and high-resolution computed tomography (HRCT). Magnetic resonance, but not HRCT, showed pericardial thickening in two patients. Magnetic resonance demonstrated reduced diastolic flow in the superior vena cava in one patient, reflecting impaired right ventricular filling. All other magnetic resonance measurements of cardiac function were normal. HRCT demonstrated mild asbestosis in three patients in which neither the chest radiograph nor magnetic resonance showed signs of parenchymal disease, and pericardiac calcification without thickening in one patient. It is concluded that magnetic resonance is superior to HRCT in identifying pericardial thickening, but that HRCT is superior to magnetic resonance in identifying asbestos-related pleural and pulmonary disease.     

Study of the beta -delayed neutron decay of 18N

The shortage of suitable liver donors for children has motivated the use of ABO-incompatible (ABO-I) grafts for transplantation in urgent situations. However, survival after ABO-I liver grafts has been reported at about 30% as compared with 80% in cases of ABO-identical or -compatible liver grafts. This difference has been attributed to antibody-mediated, hyperacute or chronic liver rejection, due to preformed ABO antibodies (alloantibodies). In this study, we report our results with ABO-I livers in children without alloantibodies at the time of transplantation. From January 1988 to June 1993, 143 OLT were performed in 122 children. Eight children received 8 ABO-I liver grafts. Of these, 7 patients were included in the study. All 7 were alloantibody free before OLT. Five children were spontaneously alloantibody free, while in 2 children, the plasma alloantibodies were eliminated before and after transplantation using intravenous infusion of specific blood group antigens of the donor blood group (soluble antigens). Immunosuppression consisted of a triple-drug treatment combining CsA, AZA, and steroids. The follow-up period was between 10 and 48 months. One child died from a surgical complication. Six children survived, but 1 died 10 months later from intestinal obstruction. There were no graft losses and no episodes of hyperacute or chronic rejection. The graft and patient survival rate was 71%. There was a 28% incidence of rejection, but all were mild (requiring steroid boluses only). Our results suggest that the absence of ABO alloantibodies at the time of and after transplantation can protect ABO-I liver grafts against antibody-mediated rejection, whether hyperacute or chronic, and that soluble antigens are effective in eliminating alloantibodies in children.     

Evaluation of serum gamma-glutamyltransferase activity as a predictor of passive transfer status in crias

OBJECTIVE: To determine the relationship between serum gamma-glutamyltransferase (GGT) activity and serum IgG concentration in neonatal crias. DESIGN: Prospective observational study. ANIMALS: 21 llama and 4 alpaca crias from 0 to 5 days old. PROCEDURE: Serum GGT activity was measured, using a commercially available kit. Serum IgG concentration was determined by use of radial immunodiffusion. With a serum IgG concentration of 1,000 mg/dl (considered adequate passive transfer), specificity and sensitivity of serum GGT activity in the detection of failure of passive transfer were determined. Regression models were developed to determine the relationship between serum GGT activity and serum IgG concentration. RESULTS: Sensitivity ranged from 0.56 to 0.89, and specificity ranged from 0.88 to 0.31, depending on the value of serum GGT activity chosen as a threshold. Proportion of crias correctly classified ranged from 0.76 to 0.52. Regression models failed to demonstrate a significant relationship between serum GGT activity and serum IgG concentration. CLINICAL IMPLICATIONS: Passive transfer status in crias cannot be accurately predicted on the basis of serum GGT activity.     

Iron requirements and iron balance during pregnancy. Is iron supplementation needed for pregnant women?

Among fertile, nonpregnant, Danish women, 33% have absent or reduced iron stores; 22% have serum ferritin values above 70 micrograms/l, i.e., iron reserves of more than 530 mg, corresponding to the net iron losses during a normal pregnancy. During pregnancy, the demands for absorbed iron increase from 0.8 to 7.5 mg/day. Controlled studies show that iron-treated pregnant women have higher serum ferritin levels, i.e., larger iron stores, and higher haemoglobin levels than placebo-treated women. A supplement of 66 mg ferrous iron daily from the beginning of the 2nd trimester prevents iron deficiency anaemia. In Denmark, general iron prophylaxis with 60-70 mg ferrous iron daily from 20 weeks of gestation is recommended by the health authorities.     

Effective shelf-life of prepared sodium hypochlorite solution

Although the tissue solvent and bactericidal properties of sodium hypochlorite are well known, the effective shelf-life of prepared sodium hypochlorite solutions is not known. The stability of sodium hypochlorite is adversely affected by exposure to high temperature, light, air, and the presence of organic and inorganic contaminants. The purpose of this study was to investigate the variables of storage conditions and time on the tissue-dissolving capacity of three different concentrations of sodium hypochlorite. Fresh frozen human umbilical cord was used as the tissue sample for this experiment. Tissue samples were dissolved at time intervals ranging from 1 day to 10 wk in 5.25%, 2.62%, and 1.0% solutions of sodium hypochlorite. The tissue-dissolving ability of 5.25% sodium hypochlorite remains stable for at least 10 wk. The tissue-dissolving ability of 2.62% and 1.0% sodium hypochlorite remains relatively stable for 1 wk after mixing, then exhibits a significant decrease in tissue-dissolving ability at 2 wk and beyond.