Immunohistochemical evidence for the presence of neuropeptides in the hypothalamic suprachiasmatic nucleus of ground squirrels

The cytoarchitecture and immunocytochemical distribution of neuropeptides (corticotropin-releasing factor, CRF; neuropeptide Y, NPY; oxytocin, OXY; vasopressin, VP; and vasoactive intestinal polypeptide, VIP) were studied in the hypothalamic suprachiasmatic nuclei (SCN) in male and female ground squirrels of two species (Spermophilus tridecemlineatus and S. richardsonii). Immunoreactive (IR) perikarya were found in sections incubated with VP or VIP antisera. VP-IR cell bodies were seen in the dorsal and medial parts of the nucleus in colchicine-treated animals. IR fibers were distributed throughout the SCN. In the ventral part of the nucleus, VIP-IR cells were seen in untreated animals and were more pronounced in colchicine-treated animals. VIP-IR fibers and terminals form a dense plexus throughout the nucleus. Furthermore, NPY-IR terminals and fibers with multiple varicosities, but no IR perikarya, were present in the suprachiasmatic nuclei. Within the borders of the SCN, no cell bodies or fibers were stained with CRF or OXY antisera in any animal.     

Localization of neuroglobin protein in the mouse brain

Neuroglobin is a recently discovered vertebrate oxygen-binding respiratory protein. In situ hybridization data demonstrated that neuroglobin-mRNA is widely expressed in neuronal cells of the central and peripheral nervous systems as well as in endocrine cells. The present study was conducted to investigate the presence of neuroglobin protein in neurons of the mouse brain. A polyclonal antibody directed against a synthetic peptide of neuroglobin was raised in rabbits and affinity-purified. The specificity of the antibody was demonstrated by ELISA and preabsorption tests. We report here for the first time that neuroglobin is expressed on the protein level in many brain sites including cerebral cortical regions, subcortical structures such as thalamus and hypothalamus, nuclei of cranial nerves in the brainstem and cerebellum. Thus, the widespread distribution of neuroglobin protein is in good agreement with its mRNA localization. Regionally differing intensities of immunostaining suggest different levels of neuroglobin protein expression, in line with the idea that brain regions show variation in their tolerance towards hypoxic conditions.     

Interpretation of chromosome mosaicism and discrepancies in chorionic villi studies

In 3,000 chorionic villi studies (CVS) 33 cases of mosaicism and 7 false-positive cell lines in all cells were seen. The mosaic cell lines were caused by aneuploidy of autosomes (13x), sex chromosomes (9x), and structural anomalies (11x). Mosaics of fetal origin were only 4 cases of trisomy 21 and one 47,XXY mosaic. In 7 cases abnormal karyotype of non-fetal origin was seen in all cells in direct studies, including trisomy 16 (3x) and trisomy 18 (2x). The combined use of direct CVS and cell cultures always uncovered the non-fetal origin of chromosome abnormalities and the study of cultured cells in all cases could have prevented 5 terminations. Complete follow-up studies demonstrated no false-negative results. Therefore, CVS can be nearly 100% accurate when both direct studies and cultures are examined in cases of mosaicism and other cell lines of possible non-fetal origin, such as trisomy 16, trisomy 18, translocation (21;21), and 45,X cells.     

Fibroblast growth factor 2 (FGF-2) differentially regulates connexin (cx) 43 expression and function in astroglial cells from distinct brain regions

Fibroblast growth factor (FGF)-2 is a peptide growth factor that promotes the generation, differentiation, and survival of neurons and glial cells. In the CNS, astroglial cells are coupled in a region-specific manner by gap junctions consisting of connexin 43 (cx43). In the present study we have investigated effects of FGF-2 and of other growth factors on the expression and function of cx43 in astroglial cells cultured from telencephalic cortex, striatum, and mesencephalon of newborn rats. Confluent cultures were maintained for two days in low serum, and then exposed to FGF-2 (10 ng/ml) for 48 h. FGF-2 caused a reduction of cx43-protein, -mRNA, and intercellular communication revealed by dye spreading. These changes occurred in cortical and striatal cells, but not in mesencephalic astroglial cells. Effects of FGF-2 were time- and concentration-dependent, with a minimal effective dose of 1 ng/ml FGF-2, and an onset of effects after 6 h of incubation. The reduction of coupling by FGF-2 was transient, since in cortical and striatal cultures coupling recovered to control levels 48 h after removal of the growth factor. Like FGF-2, transforming growth factor-β3 (TGF-β3) decreased coupling of cortical and striatal, but not mesencephalic astroglial cells. Astroglial cells from all brain regions showed a slight FGF-mediated increase in 5-bromo-2′-desoxy-uridine (BrdU) incorporation, which was abolished upon co-treatment with TGF-β3. However, TGF-β3 did not interfere with the repression of cx43-function by FGF-2. Epidermal growth factor (EGF) that has been demonstrated to influence coupling in other cell types had no effect on dye spreading but significantly increased BrdU incorporation. Our results reveal a novel function of FGF-2 on cultured astroglial cells which may be relevant to the regulation of astroglial cell connectivity in vivo. GLIA 22:19–30, 1998. © 1998 Wiley-Liss, Inc.     

Fetal loss rate after chorionic villus sampling and subsequent amniocentesis

Here we review a group of 82 patients who underwent both chorionic villus sampling (CVS) and amniocentesis in the same pregnancy during the period May 1984-May 1988. A fetal loss rate of 2.5% is documented. This is not essentially different from the sum of fetal loss rates following each of the procedures separately (CVS, 1.9%; amniocentesis, 1.0%) established during the same period.     

Endocarditis caused by Coccidioides species

Endocarditis caused by Coccidioides species has been reported rarely. Herein, we report 2 such cases and summarize 4 published reports. Coccidioidal endocarditis was found in patients who had prolonged or disseminated infection. Vegetations were identified on mitral or aortic valves or valvular rings, and embolic phenomena were observed. Diagnosis was hindered by uniformly negative results from blood cultures. The patients had a wide range of serologic titers for Coccidioides species (1:1-1:2048). The infection was fatal in 4 of the 6 patients whose cases we reviewed. We conclude that coccidioidal endocarditis is an uncommon manifestation of Coccidioides infection that connotes a poor prognosis.     

Contribution of Ca2+-activated K+ channels to hyperpolarizing after-potentials and discharge pattern in rat supraoptic neurones

The contribution of Ca(2+)-activated K(+) channels to hyperpolarizing after-potentials (HAP) of action potentials, to spike-frequency adaptation and thus to the shaping of discharge pattern, was examined in rat supraoptic magnocellular neurosecretory cells. In addition, the expression of BK channels and SK3 subunits of SK channels was studied using double immunofluorescence detection. The presence of BK channels and SK3 subunits was detected in many supraoptic neurones containing either vasopressin or oxytocin. Current-clamp recordings of current-induced spike trains revealed that HAPs comprise a fast and a slow HAP (fHAP and sHAP). Correlation analyses revealed that the increase of the fHAP in amplitude and spike broadening were correlated to a moderate gradual increase of the interspike interval and thus to weak spike-frequency adaptation. By contrast, marked prolongation of the interspike interval and strong spike-frequency adaptation depended on the appearance and on the amplitude of the sHAP. The sHAP and spike-frequency adaptation were blocked by cadmium, as well as by the SK channel antagonist apamin. The fHAP was attenuated by the BK channel antagonist iberiotoxin (IbTX), by the BK/IK channel antagonist charybdotoxin (ChTX) and by apamin. ChTX attenuated fHAPs throughout the entire spike train. By contrast, the IbTX-induced attenuation of the fHAP was restricted to the initial part of the spike train, while the apamin-induced attenuation slowly increased with the progression of the spike train. These results suggest that strong spike-frequency adaptation in supraoptic neurones essentially depends on the generation of the sHAP by activation of SK channels. Comparison of effects of IbTX, ChTX and apamin suggests a complementary contribution of SK-, BK- and IK-channels to fHAPs.     

Diagnosis of cavernomatous transformation of the portal vein

In 10 patients at the age of 17 to 59 years the diagnosis of a cavernomatous transformation of the portal vein primarily was made by sonography and was confirmed by computer tomography and angiography, respectively. These findings were seen by chance when an abdominal ultrasound was performed in order to clarify splenomegaly or esophageal varices. The characteristics of the disease are the positive proof of a convoluted agglomeration of racemose venous structures that have replaced the normal single portal vein and signs of portal hypertension. The sonographic figures are so typical that ultrasound is the decisive procedure in its diagnosis and that direct or indirect splenoportography is not necessary. The present results show that clinical manifestations of cavernomatous transformation of the portal vein are delayed sometimes in to adolescence and that invasive diagnostic methods are only necessary when shunt operation is planned.