Selective reactivity of CD8-independent T lymphocytes to a cytotoxic T lymphocyte-selected H-2Kb mutant altered at position 222 in the alpha 3 domain

To study the structural basis for specificity and affinity of cytotoxic T lymphocytes for major histocompatibility complex/peptide complexes, we have employed a cytotoxic T lymphocyte (CTL)-mediated immunoselection approach to obtain H-2Kb structural mutants which are resistant to lysis by a Kb-specific alloreactive CTL clone. In this study we describe the Kb structural mutant, designated R8.60.14, recovered following immunoselection using the CD8-dependent CTL clone 60 as a selective agent. Although serologically unaltered with respect to Kb expression, R8.60.14 is not recognized by CD8-dependent, Kb-specific CTL. DNA sequence analysis revealed a single Glu----Lys amino acid substitution at position 222 in the Kb alpha 3-domain of this variant. To determine if a direct correlation exists between CD8 dependence of a Kb specific CTL and its failure to respond to R8.60.14, we examined the lytic response against R8.60.14 by CD8-independent, Kb-specific CTL obtained from long-term culture in the presence of anti-CD8 monoclonal antibody, 3.155. CD8-independent CTL exhibit no difference in their response against the R8 parent and R8.60.14 variant. This study demonstrates unequivocally that Kb-specific recognition of R8.60.14 by CD8-independent CTL is unaltered, while the response by CD8-dependent CTL is completely abrogated. Thus, the sole basis for emergence of this variant in the CTL-mediated immunoselection approach used in this study resides in the alteration of a single CD8-binding site residue at position 222 in the Kb alpha 3 domain. The functional importance of this Glu222 residue for the interaction between the CD8 molecule on CD8-dependent CTL and the Kb alpha 3 domain is further reinforced by virtue of the recovery of the R8.60.14 variant on the basis of its resistance to lysis by a CD8-dependent CTL clone in this CTL-mediated immunoselection approach.

[A clinical analysis of atrial-ventricular sequential pacing]

Forty one patients were implanted DDD pacemakers (3 cases DDDR) from August, 1983 to July, 1990. 32 males and 9 females. The mean age was 62.3 years (range 32 to 91). 19 patients had coronary artery disease. The indication for pacing was II degrees-III degrees AV block in 16 patients and sick sinus syndrome in 25 patients. During follow-up period there were 2 patients had displacement, 4 patients had undersensing, 3 patients had pacemaker-mediated tachycardia and 3 patients had crosstalk. That was corrected through external programmer. The experience of this operation was discussed.

Viral proteins associated with the Epstein-Barr virus transactivator, ZEBRA

The BamHI Z Epstein-Barr replication activator (ZEBRA) mediates disruption of latency and induction of Epstein-Barr virus (EBV) early gene expression in latently infected lymphocytes. Polyclonal rabbit sera raised against ZEBRA were used to immunoprecipitate ZEBRA-associated proteins (ZAPs). ZAPs of 19, 21, 23, and 42 kDa were coimmunoprecipitated with ZEBRA from extracts of EBV-producing lymphoid cell lines. ZAPs were not recognized directly by the rabbit sera, but they were antigenic for EBV+ human sera. Immunoprecipitation of ZAPs by ZEBRA-specific antisera required the presence of ZEBRA. ZAPs were not coprecipitated with ZEBRA from mouse cells expressing only ZEBRA, from Raji (a cell line in which EBV is unable to complete lytic replication), or from cells treated with inhibitors of viral DNA synthesis. Thus, ZAPs are late EBV-encoded proteins. ZEBRA and ZAPs colocalized to a salt-insoluble nuclear fraction, and both were found extracellularly in crude preparations of virions. ZAPs might function to affect the cellular localization of ZEBRA, to alter its capacity to transactivate, or to influence its target gene specificity.

Topical fibronectin and aprotinin for keratectomy wound healing in rabbits

We evaluated the effect of fibronectin (an adhesive protein) and aprotinin (a protease inhibitor) as single or combined topical therapies for primary healing and prevention of recurrent corneal epithelial defects in the rabbit keratectomy wound model. The biological activity of the prepared solutions of rabbit plasma fibronectin (0.6 g/L) was suggested by in vitro assays of rabbit corneal epithelial cell adhesion and gelatin-binding affinity. In the first experiment, we compared fibronectin, albumin (a control nonadhesive protein), and saline. In the second and third experiments, fibronectin supplemented with aprotinin, aprotinin alone, and saline were compared; aprotinin was used at concentrations of 40 and 1000 kallikrein inactivating units (KIU) per mililiter. Our results suggest that topical fibronectin, 0.6 g/L, as well as aprotinin at 40- and 1000-KIU/mL concentrations, given alone or in combination, neither promote corneal epithelial wound healing nor prevent recurrent corneal epithelial defects in rabbit keratectomy wounds.

[Comparative study on the inhibitory elastase capacity of fructus Forsythiae, radix Salviae Miltiorrhizae, radix Angelicae Sinensis and Ligustrazini]

In this paper elastase capacity was measured with agar radial diffusion using elastin-agar plate. There was a linear correlation between elatase capacity and diameter of agar radial diffusion. Significant inhibitory effects of Fructus Forsythiae, Radix Salviae Miltiorrhizae, Radix Angelicae Sinensis and Ligustrazini Hydrochloridum on elastase were observed and Fructus Forsythiae proved the most effective.

Optical performance of multifocal intraocular lenses

The optical performance of one monofocal and five multifocal lenses was evaluated in the laboratory and photographically. The laboratory testing included determination of the modulation transfer function (MTF), through focus response (TFR), resolution efficiency, and Strehl ratio of each lens. The photographic testing included photographs of the Regan high contrast acuity chart at ten feet with clearest focus and 18 additional photographs in which the image was defocused using minus trial lenses in 0.25 diopter increments. A color photograph of the Kodak color chart was also taken using each lens. All testing was conducted using a 3 mm artificial pupil under ideal implant conditions with no decentration or tilt. The laboratory and photographic results demonstrate that all the multifocal lenses had a two- to three-fold increase in the depth of field with at least a 50% lower contrast in the retinal image. The photographic testing revealed a one to two line better resolution limit with the monofocal lens, which corresponded to the 12% to 41% better MTF cut-off value with the monofocal lens by laboratory testing. The measured resolution efficiencies of all six lenses were comparable. The color photographs revealed color mixing of adjacent colors with the multifocal lenses, whereas the colors appeared unchanged from the original with the monofocal lens.

Evaluation of a latex particle agglutination assay for the detection of cytomegalovirus antibody in patient serum

The Virogen CMV Antibody Test is a simple and rapid latex agglutination assay for the detection of cytomegalovirus antibody in human serum and plasma. Evaluation of this assay with respect to enzyme immunoassay yielded a sensitivity of 98% with a specificity of 100%. In comparison to CMVScan, the Virogen CMV Antibody Test had a sensitivity of 98.4% and a specificity of 100%.

Intraventricular administration of isoproterenol inhibits both heat production and heat loss mechanisms in rats

At an ambient temperature (Ta) of 8 degrees C, intraventricular administration of isoproterenol inhibited metabolic heat production and led to hypothermia in rats. In contrast, at a Ta of 22 degrees C and of 30 degrees C, isoproterenol decreased cutaneous circulation and led to hyperthermia. The data indicate that isoproterenol inhibits both heat production and heat loss mechanisms in rats.

The catecholamine mechanisms of prostaglandin E1-induced hypothermia in rats

Intraperitoneal administration of prostaglandin E1 (PGE1) produced a hypothermia in rats at room temperatue (22 degrees C). The hypothermia in response to PGE1 was due to cutaneous vasodilatation and decreased metabolic heat production. Depletion of brain 5-hydroxytryptamine (with 5,6-dihydroxytryptamine and p-chlorophenylalanine) did not alter the PGE1-induced hypothermia. However, depletion of bran catecholamines (with 6-hydroxydopamine) and blockade of central catecholaminergic receptors (with phentolamine and propranolol) both greatly reduced the PGE1-induced hypothermia. The data indicate that PGE1 lowers body temperature in rats by acting on the central catecholaminergic systems.