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Biomedical subjects

C Lane

Publications and source records attributed to C Lane.

At least 73 records · Page 4Linked to original sources

Inhibition of microvascular endothelial cell proliferation by vitreous following retinal scatter photocoagulation.

Laser photocoagulation of pig retina induced breakdown of the blood-retinal barrier, with the appearance of serum proteins in the vitreous as determined by sodium dodecyl sulphate/polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting techniques. Vitreous from lasered eyes inhibited the proliferation of cultured retinal microvascular endothelial cells in comparison with vitreous from non-lasered control eyes, and the inhibitory effect in the lasered eyes persisted for at least seven days. Inhibition was specific for endothelial cells, since no effect was observed when retinal pericytes or Tenon's fibroblasts were the target cells. These results suggest that indirect scatter photocoagulation may induce regression of neovascularisation by causing breakdown of the blood-retinal barrier and thus releasing into the vitreous serum components which result in inhibition of retinal microvascular endothelial cell growth.

Animals↗

Cerebrospinal fluid quinolinic acid concentrations are increased in acquired immune deficiency syndrome.

Dementia and brain atrophy are established features of a large proportion of patients with acquired immune deficiency syndrome (AIDS). To investigate a potential mechanism for atrophy in AIDS, we measured the concentration of the endogenous neurotoxin quinolinic acid in the cerebrospinal fluid of 10 patients with AIDS and found that they had 3-fold higher quinolinic acid concentrations than 9 age-matched control subjects: 53.8 +/- 10.7 pmol/ml versus 18.4 +/- 3.4 pmol/ml, respectively (p less than 0.005). It remains to be determined whether increased brain quinolinic acid concentrations are involved in the pathogenesis of the neuropathology of AIDS.

Acquired Immunodeficiency Syndrome↗

Transplantation of retinal pigment epithelium using a pars plana approach.

We describe a pars plana approach for transplantation of autologous retinal pigment epithelial cells from a peripheral chorioretinal biopsy to prepared Bruch's membrane at the posterior pole of the same eye. The technique has potential application in research and could be clinically applicable in the treatment of senile macular degeneration.

Animals↗

Effects of vitreous from photocoagulated eyes on retinal microvascular cells in culture: a preliminary report.

Panretinal photocoagulation was carried out in mini pigs in an attempt to elucidate the mechanisms involved in laser therapy. The effect of the vitreous from these eyes on the proliferation of retinal microvascular endothelial cells was then studied. Vitreous removed 4 days after panretinal photocoagulation had no effect on the proliferation of bovine retinal microvascular endothelial cells in basal medium but inhibited proliferation in growth medium. Control vitreous was mitogenic for the microvascular cells in basal medium but this effect was not observed in growth medium.

Animals↗

Stimulation and expansion of a human T-cell subpopulation by a monoclonal antibody to T-cell receptor molecule.

A murine monoclonal antibody (MAb) was obtained that showed unique specificity for the immunizing T-cell line HPB-ALL. This antibody, C37 (an IgG1,K) also reacted with a small (2-5%) population of normal peripheral blood T (PBL-T) cells. These C37-positive (C37+) cells were found in both the T4/Leu3+ and T8/Leu2+ subsets. Like OKT3 antibody, C37 induced T-cell mitogenesis with a peak proliferative response at day 3. In long-term cultures containing irradiated autologous feeder cells and IL-2, C37 antibody caused the selective expansion of C37+ T cells. On HPB-ALL cells C37 induced comodulation of the T3 molecule. C37 precipitated a disulfide-linked dimer characteristic of the T-cell antigen receptor consisting of an alpha-subunit (45-48 kD) and a beta-subunit (38-42 kD) from both C37+ T-cell blasts of a normal individual and HPB-ALL cells that were surface radioiodinated. However, the precipitated molecule isolated from C37 antibody-activated T-cell blasts exhibited a different pI from that isolated from HPB-ALL cells. Our studies indicate that C37 recognizes an epitope on the T-cell receptor molecule that is shared by a subpopulation of human T cells, which raises the possibility that multiple variable-region associated and/or framework-like determinants of the T-cell antigen receptor can be defined serologically and used in functional and molecular studies of T-cell subsets.

Antibodies, Monoclonal↗

Therapy for the occupationally injured hand.

Basic considerations for rehabilitation of the occupationally injured hand are discussed. Factors affecting motivation of the patient as well as clinical assessment and treatment planning are reviewed. Brief postoperative routines for common injuries are outlined.

Carpal Tunnel Syndrome↗

Biochemical characterization of a p43,12 complex: comparison with human and murine class I molecules.

A monoclonal antibody designated as C21 reacting with a p43,12 complex was developed against human thymocytes. It stained predominantly the early hematopoietic cells of the lymphoid lineage and also thymocytes, peripheral B-cells and activated T- and B-cells similarly to OKT10. The heavy chain of this antigen was a glycoprotein of Mr 43,000 (p43). Sequential immunoprecipitation with C21 and OKT10 antibodies indicated that they both reacted with an identical heavy-chain molecule. This observation was further documented by two-dimensional analysis. Monoclonal antibody C21 was used to probe a p43,12 complex further. Structural polymorphism of the p43 heavy chain isolated from T- and B-cells of different individuals was not detected by chymotryptic peptide mapping, although molecules from these cell types possessed a different charge on two-dimensional gels. An unusual observation was made regarding this complex on MOLT4 cells. The light chain co-precipitated from these cells was 12,000 daltons and had a pI distinct from that of beta 2-microglobulin but similar to the pI of the beta t molecule. Comparison between chymotryptic peptide maps of the p43 heavy chain and those of the human and murine class I molecules such as HLA, T6, H-2K, Qa-2 and TL revealed no apparent homology. We have shown, however, that the peptide backbone of p43, as studied by both tunicamycin treatment of cells and endoglycosidase F digestion of immunoprecipitates, was identical in size to that of murine Qa-1. These results suggest that the p43 antigen may be homologous to murine Qa-1 or another class I antigen encoded in the murine TL:Qa region.

Amino Acid Sequence↗

Human B-cell-stimulatory-factor production by both T4+ and T8+ lymphocytes.

The T-cell subsets responsible for the production of human B-cell-stimulatory factor (BSF) have been identified. Peripheral blood mononuclear cells (PBMNC), E-rosette-forming cells, and isolated T4+/T8+ subpopulations were cultured for 5 days with and without phytohemagglutinin (PHA) stimulation; the supernatants were then assayed for BSF. BSF activity was detected by a costimulation assay using either Staphylococcus aureus Cowan I (SAC) or goat anti-human IgM as a B-cell comitogen. Supernatants from all four PHA-stimulated cell preparations were found to exhibit BSF activity. However, supernatants from the unseparated PBMNC showed a kinetic pattern for BSF production different from that of the E-rosette-enriched T-cell population in that the BSF activity of the former reached a maximum at Day 2, followed by a rapid decrease, whereas BSF production by the latter reached a plateau at Days 4-5. Although BSF activity was observed in supernatants from both T4+- and T8+-stimulated T-cell subsets, supernatants from T8+ cells contained 50% less activity than supernatants from T4+ cells. Supernatants from the unstimulated fractions and the mitogen-containing medium control did not exhibit BSF activity. These results indicate that both the helper and the suppressor cell fractions, i.e., T4+ and T8+ lymphocytes, are responsible for the production of BSF. However, it is unclear whether the BSF activities detected in both T-cell subsets are mediated by the same or different molecular entities.

B-Lymphocytes↗

Analgesic efficacy and pharmacokinetic evaluation of meperidine and hydroxyzine, alone and in combination.

As part of a study to evaluate the analgesic efficacy of meperidine and hydroxyzine, alone and in combination, a double-blind complete crossover study of meperidine (50 mg IM), hydroxyzine (100 mg IM), meperidine (50 mg IM) plus hydroxyzine (100 mg IM), and saline placebo was conducted. Thirty patients with chronic moderate to severe pain due to metastatic cancer were evaluated as to pain relief following administration of all four study medications. All of the treatment groups showed statistically significant analgesic activity as compared to placebo. Hydroxyzine provided sustained pain relief to six hours, whereas meperidine produced analgesia up to two hours. The combination produced additive analgesia only during the first 2 hr. The pharmacokinetics of meperidine and hydroxyzine were compared to observed analgesia. Significant correlation between serum drug levels of meperidine and hydroxyzine and pain relief resulted and the serum levels of meperidine and hydroxyzine necessary for analgesia were calculated to be 0.10-0.15 mg/ml and 60-70 ng/ml; respectively. The observed analgesia of the meperidine/hydroxyzine combination was correlated with the analgesia of the individual agents and the limited additive analgesia observed with the addition of meperidine to hydroxyzine does not justify the added toxicity of the narcotic.

Aged↗

Fate of secretory proteins trapped in oocytes of Xenopus laevis by disruption of the cytoskeleton or by imbalanced subunit synthesis.

The effects of imbalanced subunit synthesis, temperature, colchicine, and cytochalasin on the secretion from Xenopus laevis oocytes of a variety of avian and mammalian proteins were investigated; these proteins were encoded by microinjected messenger RNA. Cytochalasin and colchicine together severely reduced secretion in a temperature-independent manner, the exact reduction varying among the different proteins. In contrast cytochalasin alone had no effect, whereas colchicine alone caused a smaller, temperature-dependent reduction. The synthesis and subcellular compartmentation of these proteins were unaffected by the drug treatments; however, the proteins did not accumulate in the drug-treated oocytes but were degraded. The rate of degradation of each protein was similar to its rate of exocytosis from untreated oocytes. A similar result was obtained without recourse to drugs by studying the fate of immunoglobulin light chains trapped in oocytes by a deficiency in heavy chain synthesis. These results are discussed in terms of the disruptive effects, as revealed by electron microscopy, of the drug treatments on the cytoskeleton of the oocyte.

Animals↗

Contraception.

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Abortion, Induced↗

Sequestration and turnover of guinea-pig milk proteins and chicken ovalbumin in Xenopus oocytes.

The stability and distribution of proteins within the living cell can be studied using Xenopus laevis oocytes. Microinjection of messenger RNAs and secretory proteins, followed by cell fractionation, shows that transfer of ovalbumin and milk proteins across intracellular membranes of the oocyte only occurs during their synthesis. Thus milk protein primary translation products, made in the wheat germ cell-free system, when injected into oocytes remain in the cytosol and are not recovered within membrane vesicles. Such miscompartmentalized primary milk proteins are rapidly degraded (t 1/2 0.6 +/- 0.1 h). In contrast, processed milk proteins, extracted from oocytes injected with mammary gland RNA, are relatively stable when introduced into the cytosolic compartment (t 1/2 alpha-lactalbumin 20 +/- 8 h, casein A 6 h, casein B 4 h, casein C 8.3 h). The primary ovalbumin product is also stable (t 1/2 22 +/- 9 h). Indirect evidence that rapid degradation of miscompartmentalized milk protein primary translation products may occur in vivo was obtained by the injection of massive amounts of ovalbumin and milk protein mRNA. Under these conditions there is no accumulation of primary milk protein translation products, but a polypeptide resembling the unglycosylated ovalbium wheat germ primary product can be detected in the cytosol. Only the glyclosylated forms of ovalbumin are found in the oocyte membrane vesicle fraction. We discuss the roles played by the presence of detachable signal sequences and the absence of secondary modifications in determining the rate of degradation of primary translation products within the cytosol.

Animals↗