Virulence-plasmid is associated with the inhibition of opsonization in Yersinia enterocolitica and Yersinia pseudotuberculosis.

Plasmid-cured variants of virulent strains of Yersinia enterocolitica and Y. pseudotuberculosis were obtained by selection after growth in calcium-deficient medium. To obtain antigen preparations consisting of whole bacteria the original plasmid-containing strains and the plasmid-cured variants were grown in conditions favouring expression of the temperature-inducible outer membrane proteins of Yersinia (YOP) (37 degrees C, calcium-deficient culture medium). The presence or absence of the YOP on the bacteria was verified by immunoblotting. Opsonophagocytosis of YOP-negative Yersinia preparations (YOP-) was compared to that of YOP-containing ones (YOP+) in human polymorphonuclear leukocyte (PMN) chemiluminescence (CL) assay. The attachment of complement C3b on the surface of the bacteria after opsonization with normal human serum was determined by using a fluorescent anti-C3c-antibody and flow cytometry. YOP+ bacteria resisted opsonization in the absence of specific antibodies, as indicated by diminished C3b-fixation on bacteria and weaker CL response. This implies that virulence-plasmid-coded structures provide Y. enterocolitica and Y. pseudotuberculosis with an ability to avoid complement-mediated opsonization and phagocytosis.     

Genetic diversity among Mycobacterium avium complex AccuProbe-positive isolates.

The partial 32-kDa-protein gene sequences of 22 Mycobacterium avium complex (MAC) clinical isolates that were positive by the AccuProbe MAC probe only (not by the M. avium or M. intracellulare probe) were determined. The obtained nucleotide sequences were compared with the published sequences for M. tuberculosis, M. avium, and M. intracellulare by a sequence analysis program. There was a wide range of genetic diversity among the strains studied. Most of them (16 of 22) had sequences similar but not identical to those of M. avium and M. intracellulare. These strains were considered to be true MAC strains. Five strains had sequences in the category of the novel MAIX sequence, which was very different from the sequences of other mycobacteria analyzed thus far. In addition to these strains, one isolate had a sequence that differed greatly from the reference sequences. These results support previous findings showing that the MAC probably contains several additional species. Our results also suggest that the MAC AccuProbe may react with strains that do not belong to the MAC.     

DNA aneuploidy in follicular adenomas of the thyroid gland.

The nuclear DNA content of 67 follicular adenomas and 7 adenomatous goiters was determined by flow cytometry. The DNA analysis was done with the use of paraffin-embedded tissue, but in 14 cases of follicular adenoma fresh material obtained by fine needle aspiration biopsy was also available. An abnormal DNA stemline was found in 27% (18/67) of the adenomas and in 1 (14%) of the adenomatous goiters. Four (29%) of the 14 adenomas analyzed from fresh samples were aneuploid. In none of the 12 aneuploid or 40 diploid adenomas followed for more than 5 years (mean, 7.2 years) did distant metastases develop after surgical removal of the adenoma. The paraffin blocks of cases with DNA aneuploidy were sectioned subserially at 1-mm intervals, but none of these tumors showed invasion into the capsule or blood vessels. It is concluded that DNA aneuploidy is common in histologically benign follicular adenomas of the thyroid, and that DNA aneuploidy does not appear to be associated with adverse prognosis in follicular adenomas if the tumor is surgically removed.     

Diagnostic value of DNA flow cytometry combined with fine needle aspiration biopsy in lymphomas

The nuclear DNA content of cells from 45 malignant lymphomas and from 60 benign lymph nodes obtained by fine needle aspiration was analysed to investigate the diagnostic value of DNA flow cytometry combined with routine diagnostic cytology in lymphomas. DNA aneuploidy was found in 43 per cent of lymphomas of high grade malignancy (NCI Working Formulation) but only rarely in lymphomas of intermediate- or low-grade malignancy or in Hodgkin's disease, and never in benign lymph nodes. The median percentage of proliferative cells (S + G2/M) was 22.6 per cent in diploid high-grade lymphomas, 15.3 per cent in intermediate-, and 8.1 per cent in low-grade lymphomas, as compared with 4.9 per cent in benign lymph nodes (P less than 0.0001). If the presence of DNA aneuploidy or more than 12 per cent of proliferative cells is used as a criterion for malignancy, the diagnostic accuracy of DNA flow cytometry in detecting lymphoma is 81 per cent. DNA flow cytometry suggested correct diagnosis in 10 of the 19 false positive, false negative, or indeterminate cytological findings encountered during the study. It is concluded that DNA flow cytometry combined with fine needle aspiration biopsy has diagnostic value in lymphomas, but false negative results are common especially in low-grade lymphomas; the method should therefore be used in conjunction with light microscopy.     

Immune capacity of the chicken bursectomized at 60 hr of incubation: effect of adherent cells on the production of immunoglobulins and specific antibodies in vitro

Cells from chickens bursectomized at 60 hr of incubation (Bx) and normal controls (Co) were assessed for the ability to secrete immunoglobulins and specific antibodies in vitro. Anti-tetanus antibodies were observed in the culture supernatants of cells from tetanus-immunized Co chickens. Cells from immunized Bx and nonimmunized Co chickens did not secrete specific antibodies. Cells of both Bx and Co chickens secreted similar amounts of immunoglobulins (IgM, IgG, IgA). Antigenic stimulation in vitro had no effect on the secretion of specific antibodies or on cell proliferation; this applies for Bx and Co chickens. To test whether antigenic stimulation in vitro together with adherent cells would induce antibody production in Bx cells, cocultures of peripheral blood adherent cells and lymphocytes from spleen or peripheral blood were used. Culture of lymphocytes with histocompatible and allogeneic adherent cells, with or without antigenic stimulation, did not enhance secretion of anti-tetanus antibodies from cells of Bx chickens. The adherent cells increased the secretion of total immunoglobulins, of all classes, by both Co and Bx cells alike. They also enhanced the secretion of specific antibodies by Co cells. These findings indicate that the functional failure of Bx lymphoid cells cannot be corrected by better antigenic presentation.     

The Association of Time to Organ Procurement on Short- and Long-Term Outcomes in Kidney Transplantation

Open in a separate window     

Left ventricular hypertrophy persists after successful treatment for coarctation of the aorta

Objectives. To evaluate cardiac size and function in patients with coarctation of the aorta (CoA) before and after treatment. Design. Ventricular size and function were examined by 2- and 3-dimensional echocardiography, and concentrations of natriuretic peptides measured in 15 paediatric patients before repair, and one, 6, and 12 months thereafter. Controls comprised 15 children. Results. Before repair, mitral inflow velocities and left ventricular (LV) size and wall thickness were higher in patients. Thicknesses of interventricular septum and LV posterior wall decreased after repair but increased to initial level one year thereafter. The LV end-diastolic diameter remained larger than in controls despite successful repair. The size of right ventricle increased and levels of natriuretic peptides decreased during follow-up. Levels of natriuretic peptides correlated with the smallest diameter of CoA segment and diastolic indices of LV function. Conclusion. LV hypertrophy persists and LV size remains larger than in controls after successful repair even in normotensive patients with normal growth of CoA segment. This may be due to remodelling of ventricles and the aorta caused by CoA.     

BDNF tagging polymorphisms and haplotype analysis in sporadic Parkinson's disease in diverse ethnic groups

Experimental and clinical data suggest that genetic variations in brain-derived neurotrophic factor (BDNF) gene may affect risk for Parkinson's disease (PD). We performed a case-control association analysis of BDNF in three independent Caucasian cohorts (Greek, North American, and Finnish) of PD using eight tagging SNPs and five constructed haplotypes. No statistically significant differences in genotype and allele frequencies were found between cases and controls in all series. A relatively rare BDNF haplotype showed a trend towards association in the Greek (p=0.02) and the Finnish (p=0.03) series (this haplotype was not detected in the North American series). However, given the large number of comparisons these associations are considered non-significant. In conclusion, our results do not provide statistically significant evidence that common genetic variability in BDNF would associate with the risk for PD in the Caucasian populations studied here.     

A vegan diet changes the intestinal flora

SIR, When discussing the potential mechanisms by which a vegandiet free of gluten alleviates the signs and symptoms of rheumatoidarthritis (RA), Hafström et al. [1     

Positive end expiratory pressure ventilation, renal function and renin.

Positive end expiratory pressure (PEEP) during respirator therapy can impair renal function by altering renal haemodynamics or by increasing the secretion of the antidiuretic hormone. In the present study, the effect of the commonly used 10 cm H2O PEEP for two hours on renal function and on plasma renin activity was studied in eleven intensive care patients. During the examination period, the patients received analgesic, sedative, and muscle relaxant drugs, but no diuretics. PEEP decreased the mean urinary output by 21%. Urinary specific gravity and osmolality increased. Urinary sodium excretion decreased along with urinary volume. The creatinine clearance decreased slightly, but free water clearance became less negative suggesting reduced ability of tubules to concentrate urine during PEEP. The plasma renin activity was not altered significnalty by PEEP, nor did the urinary sodium/potassium ratio change. This may indicate that the water retention induced by PEEP is not caused by the increased secretion of aldosterone. The results suggest that 10 cm H2O PEEP impairs renal function in critically ill patients and causes mainly water retention.