少枝胶质细胞瘤的形态观察

目的研究少枝胶质细胞瘤（ＯＤＧ）的超微结构及组织学特性。方法用光镜，部分用电镜及免疫组化观察６５例ＯＤＧ。结果根据ＷＨＯ有关ＯＤＧ病理分级，６５例中Ⅰ级１９例，Ⅱ级３２例，Ⅲ级１４例。结论ＯＤＧ中瘤细胞出现胶质微丝是异质性分化的结果。除按瘤细胞分化程度分级外，细胞密度、核分裂数亦有重要意义。     

The inhibitory effect of altered collagen II peptide on HLA-DRB1-restricted T-cell activation

It has been known that rheumatoid arthritis (RA)-associated antigenic peptides CII263-272 are coupled with human leucocyte antigen (HLA)-DRB1 and recognized by T-cell receptor (TCR), which in turn induced T-cell proliferation and pathogenesis of RA. Non-T-cell-stimulating type II collagen (CII) peptides might be generated by removing the amino acids responsible for TCR contact and keeping the HLA-DR-binding residues intact. In this study, a panel of altered CII peptides (APs) with consecutive or single substitutions of the TCR-contacting residues were synthesized. Through peptide binding and T-cell activation assays, we demonstrated that altered CII263-272 peptides with substitution of the TCR-contacting residues did not or barely induced T-cell activation; one of the best non-T-cell-stimulating peptide AP268-270 inhibited the binding of wild-type CII263-272 to HLA-DR1 and T-cell activation triggered by wild-type CII263-272 and HA306-318 in a dose-response manner. These data suggest that removal of the TCR-contacting residues of CII263-272 leads to HLA-DRB1 binding and low T-cell-stimulating peptides, which could potentially inhibit the T-cell response induced by HLA-DRB1-binding antigenic peptides.     

PII component of the toad electroretinogram.

1. The PII component of the electroretinogram (ERG) is comprised of the b-wave and the DC component and is thought to reflect bipolar cell activity. Although the b-wave is generated in large part by a K+/Müller cell mechanism, the origin of the DC component is unclear. In this paper we detail our investigation of the origin of the DC component. We hypothesize that the DC component is generated by a K+/Müller cell mechanism identical to that involved in b-wave generation. 2. We studied the ERG in the dark-adapted, isolated retina preparation of the toad, Bu fo marinus. We used K+ ion-sensitive microelectrodes (K+ISM), as well as conventional intra- and extracellular microelectrodes, to record [K+]o changes, the vitreal ERG, and Müller cell responses. 3. We used the excitatory amino acid receptor agonist N-methyl-DL-aspartate (NMDLA) to inhibit light responses of third-order neurons and thereby eliminate most of the ERG M-wave. In the absence of the M-wave, the ERG consisted of PII and PIII. We then superfused the retina with a solution containing both kynurenic acid (KYN) and 2-amino-4-phosphonobutyric acid (APB), which together inhibit all retinal responses proximal to the photoreceptors. In the presence of KYN and APB, the ERG consisted only of PIII. Using digital subtraction, we reconstructed PII. To our knowledge, this is the first report of the isolation of a PII component in the ERG of a nonmammalian species. 4. Using K+ISMs, we recorded the distal K+ changes in the outer plexiform layer (OPL).(ABSTRACT TRUNCATED AT 250 WORDS)     

Photodynamic inhibition of infection caused by drug-resistant variants of herpes simplex virus type I

Membranotropic amphiphilic chromophore merocyanine 540 sensitized photodynamic inhibition of drug-resistant and sensitive variants of type I herpes simplex virus in cultured Vero cell. Optimal conditions of photodamage to virus particles and infected cells were determined (merocyanine 540 concentration 1 M, illumination dose 32.5-65.0 kJ/m², exposure at early stages of infection). Infected cells actively bind the photosensitizer, which explains their selective photodamage.     

Nocardia ignorata, a new agent of human nocardiosis isolated from respiratory specimens in Europe and soil samples from Kuwait

Nocardia ignorata is a recently described species identified on the basis of a single isolate of unknown origin. Here we describe the epidemiological, phenotypic, and phylogenetic characteristics of this new species, based on five new clinical and soil isolates.     

Electrophoretic investigation of nuclear membrane ribonucleases of rat liver and hepatoma-27 cells

Preparations of the nuclear membranes were obtained from purified nuclei of rat liver and hepatoma-27 cells, and from them enzyme-containing extracts of acid-soluble proteins were then prepared. The protein extracts were subjected to disk electrophoresis in 15% polyacrylamide gel. Ribonucleases (RNases) which are constituents of the acid-soluble proteins of the nuclear membranes of normal liver were found to be present as several different components which differed in their electrophoretic mobility and in several physicochemical properties from crystalline bovine RNase and the RNase of nuclear chromatin.Institute of Problems in Oncology, Academy of Sciences of the Ukrainian SSR, Kiev. N. K. Kol'tsov Institute of Developmental Biology, Academy of Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR R. E. Kavetskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 84, No. 12, pp. 670–672, December, 1977.     

Non-occlusive bleeding times may improve the value of Ivy bleeding times

The present studies measured bleeding times, without venous occlusion, in a series of patients, whose bleeding times (+ venostasis) consistently exceeded 20 min. During these tests, the amount of blood loss (expressed as mg/min) was also quantitated. To allow comparison, normal controls were studied before and following aspirin ingestion. In normal controls, the mean standard Ivy bleeding time was 5.0 with a range of 2.5 to 7.5 min. Two hours after aspirin (650 mg), this increased to 7.3 min (range 4.0-12.0). For comparison, the non-occlusive bleeding time averaged 3.8 min (1.0-6.5) and after aspirin 5.3 min (2.5-11.5). The measured amount of blood loss was 5.0 mg/min (0-10.5 mg/min) under all of the above conditions. At the other extreme, patients with severe bone marrow failure had occluded and non-occluded bleeding times in excess of 20 min. Moreover, these were often associated with excess blood loss. By contrast, patients with "Ivy" values greater than 20 min in association with platelet counts greater than 10,000/microliters had unpredictable bleeding parameters. In the latter group, the non-occluded values ranged from 1 to greater than 20 min. Of particular note, the non-occlusive times appeared to correlate with spontaneous bleeding manifestations. Only a rare patient (1/37), whose non-occluded value was less than 20 min, had worrisome bleeding. By contrast, serious bleeding manifestations were observed in 39% whose non-occluded value exceeded 20 min. This was even higher (64%) in those with a non-occluded value greater than 20 min and excess blood loss.(ABSTRACT TRUNCATED AT 250 WORDS)