Simplified concanavalin-A sepharose adsorption method for separation of cone visual pigments from rhodopsin

Batch adsorption of chicken photoreceptor extract using Concanavalin-A Sepharose enables separation of rod and cone pigments and separation of cone pigments of different color sensitivity. In earlier work, column separations using the same adsorption medium, although effective, with high resolution, were slow, demanding and required many differential bleachings of column fractions for analysis. It is shown here that affinity separations can be performed in the batch adsorption mode to purify cattle, frog and chicken rhodopsin. These procedures are more rapid and much more convenient. An extract from the chicken retina can rapidly be separated into four fractions, including three highly enriched (80% or more) visual pigment fractions: (1) extraneous proteins, carotenoids and phospholipids; (2) short wavelength-sensitive pigments; (3) iodopsin; and (4) rhodopsin. While the resolution is not as great as that of the columns, the selectivity is sufficient to produce cone pigments, which are only slightly contaminated with rhodopsin and free of other proteins, either to experiment with directly or to enable heavier loading on high resolution columns. The method is adaptable both to highly labile pigments and to very small quantities, neither of which perform well in column separations.     

Anti-edema activity of injectable Venoruton in abdominal surgery

The anti-oedema activity of an injectable drug (HR; active principle: 0-(beta-hydroxyethyl)-rutoside) was assessed in 60 gastric extrahepatic bile duct, and large intestine surgery patients (30 being used as controls). Gastroscopy (with biopsy), gastroduodenoscopy, colonoscopy (with biopsy) and radiological examination were usually performed on the 5th and 10th post-operative days. The drug showed significant therapeutic effects: rapid resolution of oedema, especially at the sutures, leading to early cicatrisation, canalisation and the prevention of dehiscence. Finally, duration of hospitalisation was less than in the untreated cases. The gastroscopic, radiographic and biopsy findings are considered to have shown clear evidence of the drug's action against oedema formation.     

The importance of disease prevalence in transporting clinical prediction rules. The case of streptococcal pharyngitis

Because clinical prediction rules often are applied in new settings to calculate the probability of a disease, we evaluated the accuracy of three rules for predicting streptococcal pharyngitis in 310 patients. Use of the rules led to overestimations of disease probability in 47%, 82%, and 93% of the patients. When we used receiver-operating characteristic curve analysis, no rule lost power to discriminate streptococcal from nonstreptococcal causes of pharyngitis. The overestimations in disease probability likely were caused by differences in disease prevalence between our setting (5%) and the settings in which they were developed (15% to 17%). All rules led to accurate predictions when they were adjusted for the disease prevalence found in our setting using a likelihood ratio formulation of Bayes' theorem. The value of prediction rules, like that of other diagnostic tests, is affected by differences in disease prevalence in different settings. Failure to recognize and adjust for these differences may cause poor decision making or the premature dismissal of valid rules.     

A computerized national Blood Donor Deferral Register.

With blood given exclusively by volunteer donors, the American National Red Cross (ANRC) Blood Program aims to supply patients needing transfusion with blood products of the highest quality. The use of blood from volunteers, with its established greater safety, combined with laboratory testing to detect carriers of hepatitis B surface antigen (HB-SAg) and modern computer technology, creates an effective system to reduce the risk of post-transfusion hepatitis. The ANRC has devised a national Donor Deferral System, which is designed to minimize the transmission of hepatitis by blood and blood products.     

Common trafficking pathway for variant antigens destined for the surface of the Plasmodium falciparum-infected erythrocyte

Intraerythrocytic Plasmodium falciparum exports proteins to the cytosol and to the plasma membrane of the host cell. We here present data revealing the existence of a unique common pathway for the surface bound traffic of the clonally variant antigens, repeated-interspersed-antigen (RIFINS) and P. falciparum erythrocyte-membrane-protein-1 (PfEMP1). RIFIN- and PfEMP1-specific antibodies were found to stain single small vesicles (SSV) that bud off from the parasitophorus vacuolar membrane (PMV) at 6-10 h post-invasion. Large multimeric vesicle (LMV) assemblies, composed of subunits each of a similar size to that of a SSV, appeared as the dominant vesicle type carrying the variant antigens in the cytosol as the parasites developed into early trophozoite stages (> or = 16 h post-invasion). Later, more than 24 h post-invasion, large spinle-like vesicles (LSLV) built up as the LMV approached and accumulated underneath the erythrocyte membrane. LMV were found to associate both with the Maurer's cleft antigen Pf332 and with lipids as seen by fluorescent BODIPY-Ceramide staining. Co-traffic of Pf332 with RIFINS and PfEMP1 occurred in sub-compartmentalized LMV, as the variant antigens co-localized at the outer rim while Pf332 occupied the core of the vesicle complex. Formation of LMV for the trafficking of RIFINS and PfEMP1 is a prominent feature of freshly isolated P. falciparum and of in vitro propagated K+ as well as K- parasites, seemingly independent of the knob-associated histidine-rich protein (KAHRP). In vitro cultured 3D7 clones lack LMV formation and traffic the variant antigens in vesicles of a similar size to that of the SSV.     

Allergen-responsive CD4+CD25+ regulatory T cells in children who have outgrown cow's milk allergy

Cow's milk allergy in children is often of short duration, which makes this disorder an interesting clinical model for studies of tolerance to dietary antigens. Here, we studied T cell responses in 21 initially allergic children who, after a milk-free period of >2 mo, had cow's milk reintroduced to their diet. Children who outgrew their allergy (tolerant children) had higher frequencies of circulating CD4(+)CD25(+) T cells and decreased in vitro proliferative responses to bovine beta-lactoglobulin in peripheral blood mononuclear cells (PBMCs) compared with children who maintained clinically active allergy. No significant difference in proliferative activity stimulated by the polyclonal mitogen phytohemagglutinin was observed between the two groups. Depletion of CD25(+) cells from PBMCs of tolerant children led to a fivefold increase in in vitro proliferation against beta-lactoglobulin. This suggests that tolerance is associated with the appearance of circulating CD4(+)CD25(+) regulatory T (Treg) cells that are capable of suppressing the effector T cells generated 1 wk after reintroduction of cow's milk. The suppressive function of the CD4(+)CD25(+) Treg cells was shown to be partly cell contact dependent. Collectively, our study provides human data to suggest that mucosal induction of tolerance against dietary antigens is associated with the development of CD4(+)CD25(+) Treg cells.     

A comparison of anxiety and depressive symptomatology in postpartum and non-postpartum mothers

Abstract. Background: The aim of the study was to compare the distribution of symptoms of anxiety and depression among postpartum as compared with non-postpartum mothers, and to estimate the impact of the postpartum period on the risk of anxiety and depression when adjusted for other risk factors. Methods: A questionnaire survey approaching all women 18–40 years of age in two municipalities in Norway during the period 1998–1999 was conducted. A total of 2,730 women were included, of whom 416 were in the postpartum period. Only women with one or more deliveries (n = 1,794) were included in the multivariate analyses. Results: The crude prevalence of anxiety and depression was lower in postpartum as compared to non-postpartum mothers. However, when controlling for other risk factors, the odds ratio for anxiety was 1.2 (95% CI: 0.6–2.3) and for depression 1.8 (95% CI: 1.1–2.9) during the postpartum period. Conclusion: The overall risk of anxiety appeared to be the same in both groups, whereas the risk of depression was increased in the postpartum group.