Morphology and distribution of serotoninergic and oculomotor internuclear neurons in the cat midbrain

Serotoninergic fibers have been reported in both the abducens and facial nuclei of the cat. Furthermore, serotoninergic dorsal raphe and oculomotor internuclear neurons occupy similar locations in the periaqueductal gray overlying the oculomotor and trochlear motor nuclei. To resolve the issue of whether these two populations of neurons overlap, serotoninergic fibers were assayed in the abducens and facial nucleus; then the morphologies and distributions of identified serotoninergic neurons and oculomotor internuclear neurons were determined. Both the abducens and facial nuclei contained varicosities labelled with antibody to serotonin, but a much higher density of immunoreactive fibers was present in the latter, especially in its medial aspect. Distinct synaptic profiles labelled with antibodies to serotonin were observed in both nuclei. In both cases, terminal profiles contained numerous small, predominantly spheroidal, synaptic vesicles as well as a few, large, dense-core vesicles. These profiles made synaptic contacts onto dendritic and, in the facial nucleus, somatic profiles that occasionally displayed asymmetric, postsynaptic, membrane densifications. Following injection of horseradish peroxidase into either the abducens or facial nuclei, double-label immunohistochemical techniques demonstrated that the serotoninergic and oculomotor internuclear neurons form two distinct cell populations. The immunoreactive serotoninergic cells were distributed within the dorsal raphe nucleus, predominantly caudal to the retrogradely labelled oculomotor internuclear neurons. The latter were located in the oculomotor nucleus along its dorsal border and in the adjacent supraoculomotor area. Intracellular injection of horseradish peroxidase revealed that oculomotor internuclear neurons have multipolar somata with up to ten long, tapering dendrites that bifurcate approximately five times. Their dendritic fields were generally contained within the nucleus and adjacent supraoculomotor area. In contrast, putative serotoninergic neurons were often spindle-shaped and exhibited far fewer primary dendrites. Many of these long, narrow, sparsely branched dendrites crossed the midline and extended to the surface of the cerebral aqueduct. In the vicinity of the aqueduct they branched repeatedly to form a dendritic thicket. The axons of the intracellularly stained serotoninergic neurons emerged either from the somata or the end of a process with dendritic morphology, and in some cases they produced axon collaterals within the periaqueductal gray. Thus the oculomotor internuclear and serotoninergic populations differ in both distribution and morphology.(ABSTRACT TRUNCATED AT 400 WORDS)     

Analysis of the mechanism of lipoprotein(a) assembly

We have assessed the ability of a battery of purified recombinant apolipoprotein(a) (r-apo(a)) derivatives to bind to immobilized low-density lipoprotein (LDL) by ELISA. Removal of the apo(a) kringle IV type 8 and type 9 sequences dramatically reduced apo(a) binding to LDL. The binding of apo(a) to LDL was effectively inhibited by arginine, lysine, the lysine analogue ε-aminocaproic acid and proline; comparable inhibition was observed using the 17K and KIV_5–8 r-apo(a) derivatives, suggesting a direct role for sequences contained in the latter species in mediating the initial non-covalent interactions which precede specific disulfide bond formation. We also determined that r-apo(a) binds directly to a synthetic apoB peptide spanning amino acid residues 3732–3745; this interaction appeared to be mediated by sequences present in apo(a) kringle IV types 8 and 9, and could be inhibited by arginine, lysine and proline. The results of this study indicate that the efficiency of Lp(a) assembly is a direct function of the initial non-covalent interactions between apo(a) and LDL; in addition, these studies suggest that Cys3734 in apoB mediates covalent linkage with apo(a) by virtue of the ability of the apoB sequences surrounding this residue to directly interact with apo(a) KIV type 9.     

Elevated rubella antibodies in patients with chronic liver disease

Patients with autoimmune chronic active hepatitis (AICAH) and certain other chronic liver disorders often have very high titres of haemagglutination -inhibition (HI) antibodies to rubella virus. In this study it is shown, using floatation centrifugation, that the high rubella HI reactivity is not caused by nonspecific lipoprotein inhibitors but rather by antibodies specific for the rubella haemagglutinin (E1 glycoprotein). After sucrose density gradient ultracentrifugation of sera the major HI reactivity was recovered in the IgG containing fractions. The IgG antibody fraction was strongly reactive by an indirect enzyme-linked immunosorbent assay (ELISA). Higher prevalence and titres of rubella antibodies were also demonstrated by the complement fixation (CF) test using a haemagglutinin-free antigen, and by an indirect haemagglutination (IHA) test (Rubacell) using a cell-associated antigen which is distinct from the antigens used in the HI and CF tests. This high rubella antibody response is therefore demonstrated using three distinct antigen-antibody systems. By means of absorption experiments and radioimmunoprecipitation assays the coating antigen used in the IHA test was shown to reside in the E2 glycoprotein. The cause of this enhanced antibody response to rubella virus structural proteins remains elusive. © 1994 Wiley-Liss, Inc.     

Cryptosporidium parvum infection requires host cell actin polymerization

The intracellular protozoan parasite Cryptosporidium parvum accumulates host cell actin at the interface between the parasite and the host cell cytoplasm. Here we show that the actin polymerizing proteins Arp2/3, vasodilator-stimulated phosphoprotein (VASP), and neural Wiskott Aldrich syndrome protein (N-WASP) are present at this interface and that host cell actin polymerization is necessary for parasite infection.     

Comparison of six Australian isolates of Bovine herpes virus 2 based on UL24 gene after a passage in MDBK cells

A region of the UL24 gene of six Australian field isolates of Bovine herpesvirus 2 (BHV-2) was sequenced after a passage in Madin-Darby bovine kidney (MDBK) cells by polymerase chain reaction (PCR). While the PCR product covered the first half of the UL24 gene, a particular interest was focused on the 274-297 nucleotide (nt) region in which a two nt deletion had previously been detected in the BHM-1 strain of BHV-2. Most isolates tested did not generate any defective UL24 genes during the passage. However, a third of the UL24 genes of BHM-1 strain contained the two nts deletion, but only when a high multiplicity of infection (MOI) was used. Also in the isolate 554 at least a half of the UL24 genes were found to be altered independently of the MOT used. These UL24 genes had an insertion of four nts within the 274-297 nt region. The predicted truncation of the UL24 protein of both viruses occurred at the same stop codon. The region of the gene in which these mutations of the UL24 gene occurred is common to all herpesviruses.     

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CD3ζ链基因在脐带血T细胞及其CD4+和CD8+T细胞亚群中的表达特点

目的 了解脐带血T细胞及其CD4 和CD8 T细胞亚群的信号传导分子CD3ζ基因的表达特点.方法 采用SYBR Green Ⅰ荧光定量PCR和相对定量分析法检测60例脐带血单个核细胞和12例纯化脐带血CD4 及CD8 T细胞的CD3ζ基因的表达情况,以β2微球蛋白基因(β2M)作为内参,采用相对定量公式:2-△Ct×100%,计算CD3ζ基因相对mRNA表达量,60例健康成人作为对照.并根据荧光定量PCR熔解曲线特点和序列分析了解CD3ζ基因突变情况.结果 全部脐带血和健康成人外周血单个核细胞均表达CD3ζ基因,不同个体CD3ζ基因表达量有所差异,脐带血T细胞CD3ζ基因相对mRNA表达量为6.7%±5.56%,CD4 和CD8 T细胞的CD3ζ基因相对mRNA表达量分别为6.74%±2.0%和6.88%±1.76%,三者CD3ζ基因表达量均明显高于健康成人(P=0.000,P=0.034,P=0.000).序列分析结果显示尚未发现国外文献所报道的ζ链剪接异构体.结论 本研究率先报道了脐带血T细胞及其CD4 和CD8 T细胞亚群的CD3ζ基因mRNA的表达水平,为进一步了解脐带血T细胞免疫学特点提供新的基础资料.     

Coping with dental treatment: The potential impact of situational demands

Coping strategies and anxiety responding of dental patients were studied in order to test the generalizability of previous findings based on volunteer blood donors. State and trait coping measures were administered once, and a process coping scale was administered at three points throughout treatment. Self-report, behavioral observation, and psychophysiological measures of anxiety were sampled for the same periods as process coping. Findings included the replication of a negative relationship between avoidant coping and patient anxiety ratings. Fluctuations in coping were evident across periods, and impact of situational demands and constraints was introduced as an explanation for these variations. A method for direct assessment of coping consistency was introduced. On the basis of the replicable associations with anxiety measures, the ability to detect changes in coping within a situation, and the ability to provide direct evidence of coping consistency, the use of process methodology for coping assessment is encouraged.This research was conducted while the first author was supported by funding from the Medical Research Council of Canada.Portions of this research were presented at the annual convention of the Society of Behavioral Medicine, Philadelphia, 1984.     

SV40-related T-antigen expression in human meningiomas with normal and G-22-monosomic karyotype.

Six of 16 meningiomas tested in early subcultures by indirect immunofluorescence showed SV40 T-antigen. Two different antisera specific for T-antigen were used. One serum gave a positive reaction with six tumours and the other with only two. In one T-antigen positive meningioma, the typical nuclear fluorescence changed, beginning with the second subculture, into an unusual brilliant granular pattern irregularly distributed over the nuclei. In six meningiomas, a specific chromosome aberration (monosomy G 22) was established. However, up to now, no clear correlation between karyotype and T-antigen expression could be found: cells from three meningiomas with positive reactions had normal karyotypes, whereas those from three tumours with typical chromosome loss showed no T-antigen.