A serotonergic system in the brain of the Antarctic fish, Trematomus bernacchii

The immunohistochemical distribution of serotonin-containing nerve fibres and cells has been described in the brain of the Antarctic fish, Trematomus bernacchii. The largest serotonergic system was associated with the diencephalic and rhombencephalic ventricles. In particular, serotonin-positive cells have been found in the lateral recess and neuropile zone of the diencephalic ventricle, where we have identified the serotonergic portion of the paraventricular organ. Numerous serotonin cells were localized in the dorsal nucleus of the raphe, the dorsal tegmental nucleus and the central gray. Two large cell groups, arranged in a pair of well-defined columns and connecting the central gray with the dorsal reticular formation, were immunostained in the region of the trigeminal nuclei. In addition, few positive cells have been found in the preoptic area and the cerebellar valvula, and few serotonergic nerve fibres, probably belonging to the lateral lemniscus, have been identified. The distribution of serotonin elements in the brain of T. bernacchii has been compared with that described in other fish, where it showed some modifications in the immunoreactive pattern. Finally, the lack of a serotonergic system at the level of the reticular superior formation has been reported; however, it was not possible to rule out a phylogenetic or environmental explanation.     

Semen cryopreservation in golden‐headed lion tamarin,Leontopithecus chrysomelas

Wild animal genetic resource banking (GRB) represents a valuable tool in conservation breeding programs, particularly in cases involving endangered species such as the golden‐headed lion tamarin (Leontopithecus chrysomelas). Thus, we aimed to assess a sperm freezing protocol for golden‐headed lion tamarins using two different exenders: BotuBOV® (BB) and Test Yolk Buffer® (TYB). Ejaculates were collected by penile vibrostimulation from animals housed at São Paulo Zoological Park Foundation, São Paulo, Brazil, and after immediate analysis, two aliquots were diluted in BB and TYB. Postthawing samples were evaluated for total and progressive motility, plasma membrane and acrosome integrities, mitochondrial activity, susceptibility to oxidative stress, and sperm–egg‐binding. No differences between BB and TYB were found for most seminal parameters, except for acrosome integrity and susceptibility to oxidative stress (in both cases BB showed higher values). However, in spite of these differences and regardless of the extender used, postthaw sperm motility and viability with the described protocol were encouraging (on average >50% and >80%, respectively), indicating that sperm cryopreservation may be a short‐term measure for the conservation of golden‐headed lion tamarins.     

C-terminal peptide identification by fast atom bombardment mass spectrometry.

A previously described technique [Rose, Simona, Offord, Prior, Otto & Thatcher (1983) Biochem. J. 215, 273-277] permits the identification of the C-terminal peptide of a protein as the only peptide that does not incorporate any 18O upon partial enzymic hydrolysis in 18O-labelled water. Formation of chemical derivatives followed by combined g.l.c.-m.s. was used in this earlier work. We now describe the isolation from protein digests, by reversed-phase h.p.l.c., of labelled and unlabelled polypeptides and their direct analysis by fast atom bombardment mass spectrometry. Under the conditions used, the 18O label is retained throughout the separation and analysis, thus permitting assignments of C-terminal peptides to be made. Enzyme-catalysed exchange of label into the terminal carboxy group was found to occur in some cases without hydrolysis of a peptide bond. This effect, which may be exploited to prepare labelled peptides, does not prevent application of the method (two separate digests must then be used). We have applied our method to the analysis of enzymic partial hydrolysates of glucagon, insulin and of several proteins produced by expression of recombinant DNA.     

Lung T cells in hypersensitivity pneumonitis: phenotypic and functional analyses

Cells recovered from bronchoalveolar lavage (BAL) and tissue sections from transbronchial lung biopsies were studied in 16 patients with symptomatic hypersensitivity pneumonitis (HP) and in six subjects with a similar history of exposure but without features of disease by using a series of monoclonal antibodies (MoAb) detecting different lymphocyte subpopulations, including T and T subsets, B lymphocytes, and natural killer (NK) cells. Their functional activities in cytotoxic and suppressor assays and the microenvironment in the lung by using immunohistological techniques were also evaluated. It has been demonstrated that the majority of cells recovered from BAL of HP patients are represented by T8 lymphocytes, with a relevant imbalance of the T4/T8 ratio (p less than 0.001). HNK-1+ cells were markedly increased (p less than 0.001), whereas the frequency of cells bearing other NK-related markers (NK-15, VEP 13, Ab8.28, T10, M1, and Fc gamma R) were not significantly increased with respect to controls. Immunohistological study confirmed that the majority of cells infiltrating lung parenchyma are T8+ lymphocytes. The number of HNK-1+ cells detected on lung biopsies was very low in all cases, even in patients with the highest values on BAL suspensions. The evidence of cells bearing the proliferation-associated markers (Tac and T9 antigens) seems to support the hypothesis of a local proliferation in the lung. In terms of phenotypic analysis, the results observed in the group of asymptomatic individuals are qualitatively superimposable on those observed in the HP group, but the magnitude of the phenomenon is less prominent and therefore the data are not as statistically significant as that produced by the comparison between HP patients and the same controls. Functional analysis of BAL T cells from both HP patients and asymptomatic individuals showed suppressor activity in vitro, as determined by the ability to influence a pokeweed mitogen (PWM)-driven B cell differentiation assay. BAL cells from HP patients were also able to display a definite cytotoxic function in vitro, whereas BAL lymphocytes from asymptomatic subjects did not. Taken together, these data demonstrated that cells responsible for the alveolitis in patients with HP are characterized by the expansion of T cells with the phenotype and functions of both suppressor and/or cytotoxic lymphocytes. This expansion is likely to be related to a local immunologic response to the antigenic stimulus and may provide new insights into the pathogenetic mechanisms of this disease, its pathological pattern, and its management.     

The effect of post-heparin lipolytic activity on plasma lipoproteins

Summary Electron microscopy of negatively stained plasma shows that intravenous administration of heparin to healthy humans results in a fast degradation of very low density lipoproteins (VLDL), which are very rich in triglycerides (50% w/w). VLDL are also rapidly digested by post-heparin lipolytic activity when serum from non-heparinized subjects is incubated at 27°C in vitro with post-heparin serum of healthy controls.Abbreviations VLDL very low density lipoproteins - LDL low density lipoproteins - HDL high density lipoproteins - LP-X lipoprotein-X, abnormal lipoprotein characterizing obstructive jaundice