Taurine entry into perilymph of the guinea pig

Taurine is a β-aminosulfonic acid and is a ubiquitous amino acid whose role in the cochlea is not well established. In this study, its entry from blood into perilymph was investigated in the guinea pig as animal model. The penetration rate of [³H]taurine (molecular weight 125) into the perilymph of the scala vestibuli was measured 1 and 2 h after the intravenous infusion of [³H]taurine in nephrectomized animals. Results showed a rate of penetration in perilymph related to plasma at 36 ± 4.7% (n = 5) after 1 h and 43 ± 5.6% (n = 5) after 2 h. Compared to the penetration rate of urea (molecular weight 60) and mannitol (molecular weight 186) reported previously in rats, a passive entry of taurine into perilymph through the blood-perilymph barrier is suggested. Received: 30 July 1997 / Accepted: 15 January 1998     

Cytochemical characteristics of neurons in the trigeminal mesencephalic nucleus of hatchling chicks

The goal of the present study was to identify cytochemical markers characteristic of muscle afferents in hatchling chicks. To this end, we stained neurons in the trigeminal mesencephalic nucleus with a variety of markers that label subsets of neurons in avian dorsal root ganglia. We found that trigeminal mesencephalic neurons are surprisingly heterogeneous in their cytochemical make-up, expressing, to varying degrees, substance P, cholecystokinin, carbonic anhydrase, calbindin D-28k, parvalbumin, and S-100β. Calbindin D28k and S-100β appeared to be expressed equally in medial and lateral divisions of the trigeminal mesencephalic nucleus. In contrast, substance P- and cholecystokinin-immunoreactive neurons were more abundant in the medial division, whereas carbonic anhydrase activity and parvalbumin immunoreactivity were stronger in the lateral division. We were unable to detect met-enkephalin, neuropeptide Y, calcitonin gene-related peptide, vasoactive intestinal peptide, somatostatin, γ-aminobutyric acid, or tyrosine hydroxylase in the trigeminal mesencephalic nucleus. Moreover, these neurons did not appear to bind the lectin Dolichos biflorus agglutinin. The heterogeneity of expression of markers among trigeminal mesencephalic nucleus neurons, especially between neurons in the medial and lateral divisions, suggests that these neurons are functionally diverse.     

成核效应蛋白在泡凝聚融合过程中作用的初步研究

为了探讨成核效应蛋白在泡凝聚、融合过程中的作用，作者研究了胆汁中主要的促成核蛋白系统—ＣｏｎＡ结合蛋白对模拟胆汁泡的形态与脂类组成的影响，发现ＣｏｎＡ结合蛋白在加快泡凝聚与融合的同时，也使泡胆固醇增加，磷脂减少，泡胆固醇／磷脂比增高，认为成核效应蛋白促泡凝聚与融合的本质是改变了泡胆固醇饱和度。作者的初步研究还发现泡相蛋白虽量微却具有强的促成核活性；几种已知的成核效应蛋白在泡相与微胶粒相的分布有差异；胆固醇结石患者与色素结石患者相比，泡蛋白的量与促成核活性均增高。通过泡蛋白亲和染色技术，还发现ＣｏｎＡ结合蛋白能与模拟胆汁泡形成脂质－蛋白复合体。作者认为，泡中成核效应蛋白的存在或量与质的改变，在泡凝聚与融合过程中起重要作用。     

Impaired cellular host defence in peritoneal dialysis by two granulocyte inhibitory proteins

Bacterial and fungal peritonitis is associated with a high riskof morbidity and mortality in patients undergoing continuousambulatory peritoneal dialysis (CAPD). Impaired cellular hostdefence in the peritoneal cavity underlies this risk. Two granulocyteinhibitory proteins with a molecular weight of 28000 dalton(GIP I) and about 9500 dalton (GIP II) with homology to light-chainproteins and beta respectively, were isolated from peritonealdialysis effluents. In vitro, both granulocyte inhibitory proteinsinhibit PMNL glucose uptake, phagocytosis and intracellularkilling of bacteria. The IC₅₀ of GIP I or GIP II required forinhibition of half-maximal FMLP-induced or PMA-stimulated PMNLfunction was found to be in the nanomolar range, suggestingvery specific inhibition. These data may explain, at least inpart, defective local cellular host defence in CAPD patients.     

脑脊液髓鞘碱性蛋白自身抗体在脱髓鞘疾病的研究

脑脊液髓鞘碱性蛋白(MBP)自身抗体固相发光免疫分析法,是一项免疫检测新技术,目前国外尚未见到对脱髓病研究的报道。本文作者于1988.5～1989.3首先采用本法并证实其可靠性后,进入临床研究,对36例脱髓鞘病及20例其他CNS疾病者的对照组,用三项免疫指标行对比分析。CSFMBP自身抗体含量及其和同量IgG自身抗体的百分比值分别为69.23±11.95ng/ml及3.24±0.52ug/mg±gG和对照组相比,P值分别为<0.05及<0.001,有显著差异,对本病诊断有意义。     

The effects of maternal inflammation on neuronal development: possible mechanisms

That maternal inflammation adversely affects fetal brain development is well established. Less well understood are the mechanisms that account for neurodevelopmental disorders arising from maternal inflammation. This review seeks to begin an examination of possible sites and mechanisms of action whereby inflammatory cytokines - produced by the mother or by the fetal brain - could impact the developing fetus. We focus first on the placenta where cytokines maintain the immunological environment that prevents maternal rejection of the fetus. Following a brief examination of placental transfer of maternal cytokines, the focus turns on embryonic microglia, early and ubiquitous residents of the developing brain. Finally, a more intense examination of interleukin-6 (IL-6) and bone morphogenetic proteins (BMPs) provides examples of glial- or maternal-derived cytokines that are known to have profound effects on developing systems and that could, if dysregulated, have undesirable consequences for brain development.     

Characterization of Aerosols of Human Recombinant Deoxyribonuclease I (rhDNase) Generated by Jet Nebulizers

Recombinant human deoxyribonuclease I (rhDNase) is a new therapeutic agent developed to improve clearance of purulent sputum from the human airways. It is delivered by inhalation. Four jet nebulizers, T Up-Draft II (Hudson), Customized Respirgard II (Marquest), Acorn II (Marquest), and Airlife Misty (Baxter), were evaluated in vitro for their ability to deliver aerosols of rhDNase. The aerosols were generated from 2.5-mL aqueous solutions of rhDNase, at concentrations of either 1 or 4 mg/mL. In all experiments, the Pulmo-Aide Compressor (De Vilbiss) was used to supply the air to the nebulizers. Between 20 and 28% of the rhDNase dose initially placed in the nebulizers was delivered to the mouthpiece in the respirable range (1-6 µm). Evaluation of the rhDNase following nebulization in all four devices indicated that there was no loss in enzymatic activity and no increase in aggregation. Circular dichroism spectrophotometry indicated there was no change in either the secondary or the tertiary structure in rhDNase following nebulization. These results show that all four nebulizers are essentially equivalent in their ability to deliver respirable doses of rhDNase in an intact, fully active form. Changing the concentration of the solution in the nebulizer from 4 to 1 mg/mL rhDNase leads to a proportional reduction in the respirable dose delivered to the mouthpiece.     

Chronic administration of theophylline to rats induces a post-insulin binding defect in adipocyte glucose transport

Summary To determine whether adenosine is involved in long-term regulation of glucose transport in adipose tissue, we have investigated effects of administration of an adenosine receptor antagonist (theophylline) on adipocyte glucose transport. Rats were injected with theophylline (30 mg/kg, dissolved in 0.9% NaCl) daily for 7 days. Controls were injected with saline. The rats were then killed, and epididymal adipocytes were isolated. Insulin-stimulated glucose transport rates were decreased by about 25%–30% in the cells from theophylline-treated rats at all insulin concentrations tested. The half-maximally effective concentration of insulin was not altered (6.5±0.5 and 6.7±0.5 mU/l in control and treated cells respectively), suggesting a post-insulin binding defect. This was confirmed by the finding that ¹²⁵I-insulin binding to the cells was not altered. Adenosine receptor number and affinity (measured on detergent-solubilized adipocyte extracts using ¹²⁵I-hydroxyphenylisopropyl adenosine) was also not changed by theophylline treatment. We conclude that theophylline administration causes decreased glucose transport rates in rat adipocytes at a post-insulin binding level. Thus, chronic adenosine receptor blockade impairs adipocyte glucose transport, suggesting that adenosine is involved in long-term regulation of glucose metabolism in adipose tissue.     

Cerebellar nuclear afferents--where do they originate? A re-evaluation of the projections from some lower brain stem nuclei

Summary Cerebellar nuclear afferents from some caudal brain stem nuclei in the cat were studied by means of retrograde transport after implantation of the wheat germ agglutinin-horseradish peroxidase complex in crystalline form in the cerebellar nuclei. The findings give evidence that projections to the cerebellar nuclei from certain nuclei of the reticular formation proper (e.g., from the gigantocellular reticular nucleus) are very modest, while there appears to be no or extremely few cerebellar nuclear afferents from the paramedian reticular, spinal trigeminal, gracile, cuneate and external cuneate nuclei. Previous tracer studies have given evidence that also the pontine and red nuclei send very few, if any, fibres to the cerebellar nuclei. All these brain stem regions are known to project to the cerebellar cortex. This relative lack of mossy fibre collaterals to the cerebellar nuclei is discussed with references to previous literature on the distribution of cerebellar nuclear afferents, and the problem of how the cerebellar nuclei are facilitated is considered.Abbreviations Br.c. superior cerebellar peduncle (brachium conjunctivum) - Br.p. middle cerebellar peduncle (brachium pontis) - C.r. interior cerebellar peduncle (restiform body) - HRP horseradish peroxidase - L left - N.c. cuneate nucleus - N.c.e. external cuneate nucleus - N.c.t. nucleus of corpus trapezoideum - NIA anterior interposed nucleus - NIP posterior interposed nucleus - NL lateral (dentate) nucleus - N.l.l. nuclei of lateral lemniscus - NM medial (fastigial) nucleus - N.m.X. dorsal motor vagal nucleus - N.mes. mesencephalic trigeminal nucleus - N.r.l. lateral reticular nucleus (nucleus of the lateral funiculus) - N.r.p. paramedian reticular nucleus - N.r.t. reticular tegmental pontine nucleus - N V, VI, VII, XII root fibres of cranial nerves - Ol.s. superior olive - P.h. nucleus praepositus hypoglossi - Py pyramid - R right - R.gc. gigantocellular reticular nucleus - R.l. lateral reticular nucleus of Meessen and Olszewski - R.p.c. caudal pontine reticular nucleus - R.pc. parvicellular reticular nucleus - R.v. ventral reticular nucleus - Tr.sp.V. spinal tract of the trigeminal nerve - T.s. solitary tract surrounded by nucleus of solitary tract - V.m. medial vestibular nucleus - WGA wheat germ agglutinin - WGA-HRP wheat germ agglutinin-horseradish peroxidase conjugate - V, VI, VII, X, XII motor nuclei of cranial nerves     

Noradrenergic projections to brainstem nuclei: evidence for differential projections from noradrenergic subgroups

Retrograde transport of the fluorescent tracer True Blue was used in combination with immunohistochemical staining of dopamine-beta-hydroxylase (a marker protein for noradrenergic neurons) to determine the origin of noradrenergic projections to three cranial nerve nuclei: 1) the motor nucleus of the trigeminal nerve, 2) the motor nucleus of the facial nerve, and 3) the spinal trigeminal nucleus pars interpolaris. Noradrenergic cells in the rat brainstem were divided into subgroups and their numbers were determined in serial sections stained with an antiserum to rat dopamine-beta-hydroxylase. Following tracer injections into the three brainstem nuclei, retrogradely labeled noradrenergic neurons were counted and the percentage of True Blue-labeled noradrenergic cells in each subgroup was calculated. Injections of tracer into the three cranial nerve nuclei resulted in distinctly different labeling patterns of noradrenergic cells. Of the total number of norepinephrine neurons projecting to the motor nucleus of the trigeminal nerve, 68% were observed within the A7 cell group; 75% of those innervating the motor nucleus of the facial nerve were found in the A5 cell group, and 65% of those projecting to the spinal trigeminal nucleus pars interpolaris were present in the locus ceruleus and subceruleus. These findings indicate that norepinephrine cells in the rat brainstem do not constitute a homogeneous population of cells but that several discrete systems can be identified that differ not only in topography but also in the terminal distribution of their axons. This combined retrograde transport-immunohistochemical study reveals a much higher degree of topographic order in the projections of norepinephrine neurons than has previously been recognized. The observation of differential projections of noradrenergic subgroups argues against the notion of a global influence of these cells over functionally diverse areas of the brainstem.