Development of AMPA-selective glutamate receptors in the auditory brainstem of the barn owl

AMPA receptor specific antibodies were used to study the distribution and development of glutamate receptor subtypes (GluR1-4) in nucleus magnocellularis, angularis, laminaris, and the superior olive of the barn owl. Each nucleus in the adult barn owl expresses characteristic levels of AMPA receptor subtypes, and all are enriched in the subunits associated with rapid desensitization (GluR2 and 4). In the auditory hindbrain of the barn owl, the levels of expression of all AMPA receptors were very low at the time of hatching. In all nuclei, the level of GluR1 immunoreactivity was low to undetectable at all ages studied. In the cochlear nuclei, angularis and magnocellularis, levels of GluR2/3 and GluR4 immunoreactivity increased over the first 2 weeks after hatching, coinciding with the morphological maturation of auditory nerve terminals in NM. In the nucleus laminaris and in the superior olive, GluR2/3 and GluR4 immunoreactivity reached adult-like patterns by 3 weeks after hatching. Thus, adult-like patterns of immunoreactivity appeared at least 1 month before the end of the sensitive period in all nuclei studied.     

Vitamin E supplementation attenuates myointimal proliferation of the abdominal aorta after balloon injury in diet-induced hypercholesterolemic rabbits

The effects of vitamin E supplementation in a dose of 450 mg/1000 g chow on the myointimal proliferation of the abdominal aorta after balloon injury were studied in 4 groups of rabbits (24 each). The animals were fed regular diet, regular diet plus vitamin E, 1% cholesterol-enriched diet, and 1% cholesterol-enriched diet plus vitamin E. Each animal underwent a balloon injury of the abdominal aorta and left common iliac artery after 2 weeks of feeding. The animals remained on their respective diets thereafter. In 8 balloon-injured and 8 sham-operated animals of each group, the abdominal aortas were harvested 3 days after the procedure for the analysis of prostacyclin and thromboxane A2 synthesis, thiobarbituric acid reactive substances (TBARS) levels, enzyme activities of glutathione reductase (GR) and glutathione peroxidase (GP) as well as reduced (GSH) and oxidized (GSSG) glutathione levels, 3H-thymidine uptake, cholesterol as well as vitamin E contents. In the other 8 balloon-injured rabbits of each group, the tissue was harvested 3 weeks later for the morphometric study. In dependent of high cholesterol feeding, the vitamin E-treated rabbits had lower aortic production of thromboxane B2, higher 6-keto-PGF1 alpha and higher 6-keto-PGF1 alpha/thromboxane B2 ratios in both procedures. The aortic TBARS levels of the rabbits treated high cholesterol alone were significantly higher than the other three groups in both procedures. Balloon injury had a trend to increase TBARS levels and had significantly higher 3H-thymidine uptake (each p < 0.001) than sham operation in each group. Vitamin E supplement to high cholesterol diet or regular chow reduced aortic TBARS levels (p < 0.005 and 0.01, respectively) and 3H-thymidine uptake (p < 0.05 and 0.01, respectively), as well as attenuated myointimal proliferation of the abdominal aorta and left common iliac artery after balloon injury; but only supplement to high cholesterol diet reached statistical significances (both p < 0.05 compared to rabbits fed high cholesterol alone). These results suggest that vitamin E supplement changes prostanoid metabolism to a favorable pattern and reduces lipid peroxidation of the abdominal aortic wall, thus attenuates myointimal proliferation after balloon injury; these presentations are particularly obvious in diet-induced hypercholesterolemic rabbits.     

Laser-induced chorioretinal venous anastomosis for nonischemic central or branch retinal vein occlusion

Sea urchin embryos have provided excellent material for experimental and molecular analyses of the processes of cell and axis specification during embryogenesis. These studies revealed the tremendous developmental plasticity of cells in early embryos and the roles that cell-cell interactions play in determining cell fates. Details concerning sea urchin development can be found in a number of excellent reviews. This review summarizes experimental and molecular studies relating to axis determination and cell fate specification in echinoid embryos. Correlations are drawn from research carried out on the development of axial systems in other organisms.     

IL-5 is required for eosinophil recruitment, crystal deposition, and mononuclear cell recruitment during a pulmonary Cryptococcus neoformans infection in genetically susceptible mice (C57BL/6)

CBA/J (highly resistant), BALB/c (moderately resistant), and C57BL/6 (susceptible) mice displayed three resistance patterns following intratracheal inoculation of Cryptococcus neoformans 52. The inability to clear the infection correlated with the duration of the eosinophil infiltrate in the lungs. The role of IL-5 in promoting the pulmonary eosinophilia and subsequent inflammatory damage in susceptible C57BL/6 mice was investigated. C57BL/6 mice developed a chronic alveolar, peribronchiolar, and perivascular eosinophilia following C. neoformans infection. This resulted in the accumulation of intracellular Charcot-Leyden-like crystals in alveolar macrophages by wk 4 and the extracellular deposition of these crystals in the bronchioles with associated destruction of airway epithelium by wk 6. IL-5 mRNA was expressed in the lungs, and injections of anti-IL-5 mAb prevented eosinophil recruitment and crystal deposition but did not alter cryptococcal clearance. Depletion of CD4+ T cells (but not CD8+) ablated IL-5 production by lung leukocytes in vitro and eosinophil recruitment in vivo. Neutralization of IL-5 also inhibited the recruitment of macrophages, CD8+ T lymphocytes, and B lymphocytes by 47 to 57%. Anti-IL-5 mAb inhibited CD4+ T lymphocyte recruitment by 30% but did not affect neutrophil recruitment. Thus, the development of a chronic eosinophil infiltrate in the lungs of C. neoformans-infected C57BL/6 mice is a nonprotective immune response that causes significant lung pathology. Furthermore, IL-5 promotes the recruitment and activation of eosinophils, resulting in the recruitment of additional macrophages and lymphocytes into the lungs.     

A method of limited replication for the efficient in vivo delivery of adenovirus to cancer cells

Replication-deficient viral vectors are currently being used in gene transfer strategies to treat cancer cells. Unfortunately, viruses are limited in their ability to diffuse through tissue. This makes it virtually impossible to infect the majority of tumor cells in vivo and results in inadequate gene transfer. This problem can be addressed by allowing limited viral replication. Limited viral replication facilitates greater penetration of virions into tissue and can improve gene transfer. We have developed a strategy of limited viral replication using AdRSVlaclys, a chemically modified E1-deleted adenovirus, to codeliver an exogenous plasmid encoding the adenovirus E1 region. This system allows one round of viral replication. We examined the effect of this limited adenovirus replication in vitro and in vivo. In culture, codelivery of virus and pE1 resulted in a large increase in infected cells when compared with control cells exposed to virus and pUC19. In experiments on nude mice bearing HeLa ascites tumors, intraperitoneal injection of AdRSVlaclys/pE1 resulted in a significantly higher percentage of infected HeLa cells as compared with the PBS controls (p < 0.05) or the AdRSVlaclys/pUC19 controls (p < 0.01). These data demonstrate that the transcomplementation of replication-deficient adenovirus with exogenous E1 DNA leads to limited replication, and this controlled replication enhances gene transfer efficiency of adenovirus in vivo.     

DNA polymerase fidelity: from genetics toward a biochemical understanding

This review summarizes mutagenesis studies, emphasizing the use of bacteriophage T4 mutator and antimutator strains. Early genetic studies on T4 identified mutator and antimutator variants of DNA polymerase that, in turn, stimulated the development of model systems for the study of DNA polymerase fidelity in vitro. Later enzymatic studies using purified T4 mutator and antimutator polymerases were essential in elucidating mechanisms of base selection and exonuclease proofreading. In both cases, the base analogue 2-aminopurine (2AP) proved tremendously useful-first as a mutagen in vivo and then as a probe of DNA polymerase fidelity in vitro. Investigations into mechanisms of DNA polymerase fidelity inspired theoretical models that, in turn, called for kinetic and thermodynamic analyses. Thus, the field of DNA synthesis fidelity has grown from many directions: genetics, enzymology, kinetics, physical biochemistry, and thermodynamics, and today the interplay continues. The relative contributions of hydrogen bonding and base stacking to the accuracy of DNA synthesis are beginning to be deciphered. For the future, the main challenges lie in understanding the origins of mutational hot and cold spots.     

Susceptibility of heterozygous MnSOD gene-knockout mice to oxygen toxicity

OBJECTIVE: To study type IV collagen of skin and serum in patients with ALS. BACKGROUND: Collagen abnormalities of skin have been reported in ALS patients. However, little is known concerning type IV collagen in ALS. METHODS: We studied type IV collagen immunoreactivity of skin and measured serum levels of the 7S fragment of the N-terminal domain of type IV collagen (7S collagen) in patients with ALS and control subjects. RESULTS: The basement membrane as well as blood vessels of skin in ALS patients was weakly positive for type IV collagen as compared with those of diseased control subjects. This weak immunostaining became more pronounced as ALS progressed. The optical density for type IV collagen immunoreactivity in ALS patients was significantly lower (p < 0.001) than in diseased control subjects and was significantly decreased with duration of illness (r = -0.85, p < 0.01). Serum 7S collagen levels in patients with ALS were significantly decreased (p < 0.01) as compared with those in diseased and healthy control subjects and were negatively and significantly associated with duration of illness (r = -0.81, p < 0.001). There was an appreciable positive correlation between concentrations of serum 7S collagen and the density for type IV collagen immunoreactivity in ALS patients (r = 0.81, p < 0.02). CONCLUSIONS: These data suggest that a metabolic alteration of type IV collagen may take place in the skin of ALS patients and that the decreased levels of serum 7S collagen may reflect a decreased type IV collagen immunoreactivity of skin in patients with ALS.     

Phase I/II study of the toxicity, pharmacokinetics, and activity of the HIV protease inhibitor SC-52151

A significant restriction was demonstrated in the ability of herpes simplex virus type 1 virion host shutoff (vhs) mutant viruses to invade the corneal epithelium. Viral replication and invasion was confined to the areas of the cornea which were scarified prior to infection. Differences between wild-type and vhs mutant replication in corneas in vivo were 100- to 1000-fold at all timepoints postinfection. Smaller but still significant growth restrictions were observed in cultured corneal cells. This difference between in vitro and in vivo is not likely to be due to differences in cell cycle status since vhs-induced RNA degradation can occur in both cycling and noncycling cells in vitro. The vhs function is therefore important for invasion of the cornea and secondarily the nervous system and is thereby required for efficient establishment of latency.