Experimental myocarditis induced by two different coxsackievirus B3 variants: Aspects of pathogenesis and comparison of diagnostic methods

The ability of two coxsackievirus B3 (CBV3) variants to induce myocarditis in BALB/c mice was studied and plaque-forming assay, polymerase chain reaction (PCR), in situ hybridization, and immunohistochemistry were compared for detecting viruses and viral components in the myocardium. The virological findings were related to histopathologic and ultrastructural changes in the myocardium. CBV3-W induced severe myocarditis characterized by massive myocyte necrosis. Widely distributed myocyte damage clearly preceded modest inflammatory infiltrates in the myocardium. In contrast, CBV3-MI induced mild myocardial injury. Both variants caused fulminant pancreatitis with nearly complete necrosis of the exocrine pancreas. CBV3 RNA was identified by PCR in the myocardium of CBV3-W-infected mice until the end of the follow-up period of 14 days. Moreover, semiquantitative results were obtained when the PCR/ hybridization results were analyzed by a phosphor imaging system. lmmunohistochemistry and in situ hybridization from formaldehyde-fixed, paraffin-embedded specimens were highly similar in detecting viral components during the early stages of the myocardial injury. The results indicate that: (i) direct viral damage plays an essential role in acute murine CBV3-induced myocarditis, (ii) PCR appears a useful and sensitive diagnostic method in acute myocarditis, and (iii) immunohistochemistry as a specific and relatively rapid method might be practicable also in studying the early stages of acute myocarditis from archival clinical material. © Wiley-Liss, Inc.     

Hormonal responses and cardiac filling pressures in head-up or head- down position and pneumoperitoneum in patients undergoing operative laparoscopy

In order to determine if there are differences in stress responses, as reflected in neuroendocrine activation, we have compared data from two groups of patients undergoing laparoscopic surgery either in the head- up position for cholecystectomy or in the head-down position for hysterectomy. Arterial blood samples were obtained for measurement of serum concentrations of cortisol, catecholamines, renin activity and atrial natriuretic peptide (measured as N-terminal peptide of proANP), and haemodynamic data (pulmonary capillary wedge pressure, PCWP) were collected at the following times: in awake patients, supine at rest (baseline); in awake patients in the position used during surgery; during laparoscopy; and 2 h after surgery. The same anaesthetic technique and normocapnic mechanical ventilation were used in both groups. There were no significant differences between groups in cortisol or adrenaline concentrations, or in renin activity. There was, however, a three-fold increase in cortisol towards the recovery period in both groups. Noradrenaline concentrations increased more in the head- up group suggesting increased sympathetic nervous activity. In awake patients, plasma NT-proANP concentrations were significantly higher in the head-down tilt compared with the head-up position, and NT-proANP correlated well with PCWP. During pneumoperitoneum, however, NT-proANP concentrations remained low in spite of increased PCWP suggesting that inflation of the abdomen interferes with venous return. In conclusion, abdominal surgical laparoscopy in both the head-up and head-down positions caused marked activation of neuroendocrine responses. The two surgical positions, however, differed in their effect on the circulation. In awake patients, head-down tilt was associated with increased concentrations of plasma NT-proANP, indicating increased venous return and atrial stretch.      

Quantitative representation of two germ-line V genes in the early antibody response to 2-phenyloxazolone

Early anti-phenyloxazolone antibodies of BALB/c mice include a subset that bears the nearly or totally unmutated VH-Ox1 sequence. A fraction of this subset also bears the nearly or totally unmutated V kappa-Ox1 sequence. The whole subset is recognized by an anti-idiotype serum 495 and the VH-Ox1/V kappa-Ox1 fraction also by another anti-idiotype serum 260. Frequencies of the VH-Ox1 subset and its V kappa-Ox1 fraction in early IgM and IgG antibodies were determined by typing hybridomas with anti-idiotype antisera. The whole subset appears to make up approximately one half of IgG antibodies, two thirds of this being 495+/260+ in both isotypes. IgM data are less certain but the same frequencies may be valid. Affinities of 495+/260+ antibodies ranged from 1.3 X 10(6) to 11 X 10(6), affinities of 495+/260- antibodies from 0.47 X 10(6) to 1.1 X 10(6), and affinities of doubly negative antibodies were less than 0.41 X 10(6). High affinity is probably an explanation for the high proportion (one third) of the 495+/260+ antibodies in the early response. Doubly negative (and low-affinity) hybridomas may not have been classified as producers of phenyloxazolone antibodies in earlier studies, and this could explain the still higher reported frequency (73%) of VH-Ox1/V kappa-Ox1 antibodies.     

COMPLETE RESTORATION OF BURSA-DEPENDENT IMMUNE SYSTEM AFTER TRANSPLANTATION OF SEMIALLOGENEIC STEM CELLS INTO IMMUNODEFICIENT CHICKS

For transplantation of semiallogeneic bursal stem cells into cyclophosphamide-treated 3-day old chicks, two lines of chickens homozygous at the major histocompatibility locus and their F₁ hybrids were used in reciprocal combinations. The semiallogeneic transplantations resulted in a complete restoration of antibody formation to sheep red blood cells (SRBC) and Brucella, of microscopic morphology of bursa fabricii, and of germinal center formation in the spleen. In contrast, allogeneic bursal stem cells were not effective in restoring secondary response to SRBC and germinal center formation, while they were able to reconstitute anti-Brucella responses and bursal morphology. These findings indicate an effective cooperation of donor and host cells leading to a complete restoration of the bursa-dependent lymphoid system, when the donor and recipient share at least one haplotype determining the major histocompatibility antigen complex.