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Biomedical subjects

D Hillman

Publications and source records attributed to D Hillman.

At least 37 records · Page 2Linked to original sources
PubMed1992

Noradrenergic-induced expression of c-fos in rat cortex: neuronal localization.

beta Adrenoceptors in the rat forebrain have been shown to exist predominantly on astrocytes. Studies were undertaken to determine whether the cellular localization of c-fos expression caused by the activation of brain beta receptors would have a similar cellular localization. Double label light and electron microscopic immunohistochemical experiments with a glial (glial fibrillary acidic protein, GFAP) and neuronal marker (neurofilament protein, NFP) were undertaken in rats treated with the adrenergic drug, yohimbine. These studies revealed a predominantly neuronal localization of Fos protein in the cerebral cortex. The latter results indicate that neurons are the postsynaptic noradrenergic target cells in which this immediate early gene is expressed in response to the stimulation of beta adrenoceptors. The possible relation of these findings to the glial localization of these receptors is discussed.

Animals↗
PubMed1991

Localization of P-type calcium channels in the central nervous system.

The distribution of the P-type calcium channel in the mammalian central nervous system has been demonstrated immunohistochemically by using a polyclonal specific antibody. This antibody was generated after P-channel isolation via a fraction from funnel-web spider toxin (FTX) that blocks the voltage-gated P channels in cerebellar Purkinje cells. In the cerebellar cortex, immunolabeling to the antibody appeared throughout the molecular layer, while all the other regions were negative. Intensely labeled patches of reactivity were seen on Purkinje cell dendrites, especially at bifurcations; much weaker reactivity was present in the soma and stem segment. Electron microscopic localization revealed labeled patches of plasma membrane on the soma, main dendrites, spiny branchlets, and spines; portions of the smooth endoplasmic reticulum were also labeled. Strong labeling was present in the periglomerular cells of the olfactory bulb and scattered neurons in the deep layer of the entorhinal and pyriform cortices. Neurons in the brainstem, habenula, nucleus of the trapezoid body and inferior olive and along the floor of the fourth ventricle were also labeled intensely. Medium-intensity reactions were observed in layer II pyramidal cells of the frontal cortex, the CA1 cells of the hippocampus, the lateral nucleus of the substantia nigra, lateral reticular nucleus, and spinal fifth nucleus. Light labeling was seen in the neocortex, striatum, and in some brainstem neurons.

Animals↗
PubMed1984

Beta globin messenger RNA content of bone marrow erythroblasts in heterozygous beta-thalassemia.

RNA from bone marrow erythroblasts and peripheral blood reticulocytes of patients with heterozygous beta-thalassemia was analyzed for relative content of alpha and beta globin messenger RNA by molecular hybrization. Erythroblasts from nonthalassemic patients exhibited approximately the same alpha and beta globin mRNA content (beta/alpha mRNA ratio = 0.8-1.0) as circulating reticulocytes (beta/alpha mRNA ratio = 0.74-1.2). The mRNA ratios corresponded well to levels of globin synthesis observed in bone marrow and peripheral blood. Erythroblasts from four patients with heterozygous beta-thalassemia also exhibited approximately the same beta/alpha mRNA ratios in bone marrow erythroblasts (0.34-0.59) as in reticulocytes (0.34-0.4): beta globin mRNA was clearly deficient in bone marrow erythroblasts. Globin biosynthesis by erythroblasts of beta-thalassemia heterozygotes was balanced despite the mRNA deficiency (beta/alpha = 0.9-1.0), suggesting that post-translational phenoma (eg, proteolysis of free globin chains), rather than instability of beta mRNA, accounts for the balanced globin chain synthesis frequently observed in bone marrow erythroblasts of patients with beta-thalassemia trait.

Adult↗
PubMed1984

Adenovirus early region 1A protein activates transcription of a nonviral gene introduced into mammalian cells by infection or transfection.

Transcription from all early adenovirus promoters is stimulated by a 289 amino acid phosphoprotein encoded in the pre-early transcription unit E1A. To determine if this protein could act on a nonviral gene placed on the viral chromosome, adenovirus recombinants were constructed in which the rat preproinsulin I gene, including its promoter region, was substituted in both orientations for E1A. Preproinsulin mRNA synthesis from these recombinants was greatly stimulated after infection of line 293 cells, which constitutively express E1A protein, compared to HeLa cells, which do not. Expression of the preproinsulin gene was also greatly stimulated when HeLa cells were coinfected with the recombinants and wild-type adenovirus or a mutant defective in a second E1A protein, but much less so by coinfection with a mutant defective in the 289 amino acid phosphoprotein. Much of the E1A-induced preproinsulin mRNA had a 5' end at the same position as the preproinsulin mRNA isolated from insulinoma cells, but a considerable fraction had 5' ends mapping heterogeneously within several hundred nucleotides of this site. Preproinsulin mRNA was also detected in 293 cells but not HeLa or HEK cells after transfection of a plasmid containing the preproinsulin gene with no adenovirus sequence. This indicates that there is no cis-acting adenovirus sequence required for E1A protein stimulation of preproinsulin transcription. Infection of rat cells with adenovirus did not induce detectable mRNA synthesis from the endogenous preproinsulin I gene. These results demonstrate that the E1A protein can induce expression of a nonviral gene when it is newly introduced into mammalian cells by viral infection or transfection, but it does not induce the endogenous cellular gene.

Adenoviruses, Human↗
PubMed1983

Intrauterine exposure to halothane increases murine postnatal autotolerance to halothane and reduces brain weight.

The effect of halothane on prenatal development was assessed using the appearance of postnatal tolerance to the anesthetic and its effect on brain weight. Eighteen 3-month-old mice were repeatedly tested in a rotating cage for loss of righting reflex during exposure to increasing concentrations of halothane on 15 occasions to determine whether or not tolerance to halothane developed. Of these, nine mice were born to dams exposed for 30 min to 2% halothane on days 14 and 17 of gestation. The other nine mice (controls) were born to dams exposed to 100% oxygen for 30 min at the same stage of pregnancy. There was no significant difference in tolerance to halothane between the groups during the first nine days of repeated exposure to halothane. By the 13th and 15th days, however, mice exposed to halothane in utero became more tolerant to 1% halothane than did controls (P less than 0.025). In addition, the mean total brain weight of six 7-week-old mice exposed to 2% halothane in utero for 30 min on days 14 and 17 of gestation was found to be significantly less than the mean total brain weight of six control mice not exposed to halothane in utero (20.83 +/- 0.27 g and 23.07 +/- 0.51 g, respectively, P less than 0.0025). This difference occurred mainly in the brain stem rather than in the forebrain and cerebellum.

Animals↗
PubMed1982

Discussion: Implications of the stress syndrome to animal performance and health.

Similarities of blood metabolic and immunologic reactions that occur in cattle exposed to heat stress, other chronic stress-inducing environmental factors, and administration of pituitary, adrenal, and thyroid hormones have been described. Chronic stress can predispose cattle to both metabolic and infectious diseases. Improved characterization of endocrine, metabolic, and immunologic relationships offers promising means for studying effects of various treatment regimens on animal health, production, and reproduction.

Adrenal Glands↗
PubMed1980

Chronic iodine toxicity in dairy cattle: blood chemistry, leukocytes, and milk iodide.

Preliminary data from farm herds fed excessive dietary iodide and displaying signs of iodism indicated hyperglycemia, hypocholesterolemia, and a neutrophilic-lymphopenic shift in blood leukocytes. Subsequently blood, milk, and urine were analyzed from 90 cows in 10 herds fed normal (average 16 mg/cow daily) or high (average 164 mg) iodide as ethylenediamine dihydriodide for prophylactic purposes and from one herd fed iodinated casein for 3 wk. Glucose, area nitrogen, and neutrophils were higher while cholesterol and lymphocytes were lower in blood from cows fed high iodide. Milk iodide averaged .37 +/- .03 ppm from normal and 2.16 +/- .25 from herds fed high iodide. Neutrophils, glucose, protein, and globulin of serum increased while lymphocytes, cholesterol, and thyroxine decreased as iodide in milk and urine increased. Signs of iodism included lacrimation, coryza, conjunctivitis, coughing, hair loss, and exophthalmus. These findings corroborate other reports that excessive iodide alters metabolism and is toxic to immune mechanisms, suggesting that dietary iodide should be limited to nutritional requirements and prolonged prophylactic or therapeutic use should be avoided.

Animals↗
PubMed1979

Ultrafast laser scanner microscope.

Advances in monolayer deposition of cervical cells have removed one of the last serious obstacles to the design of high-resolution automated diagnostic assessment systems. In this article, we describe the design considerations for a system that is capable of acquiring, within 60 sec, a 0.5 micron digitized image of a 4 cm2 area on a standard glass slide. The most feasible approach is found to be a system using a rotating polygon to sweep the focused spot from a laser across a 2-mm scan line while the slide is uniformly translated perpendicular to the scan direction the use of laser sources (a helium-neon laser at 632 nm and a krypton ion laser at 568 and/or 476 nm) as compared to the incoherent light sources used in conventional microscope systems alleviates many of the optical design problems and provides the proper wavelengths needed for recognition of Papanicolaou stained cells. We also find that focus control of the scanning spot should be achievable using a technique involving a holographic grating. Other relevant considerations such as sample heating problems, multiphoton absorption by the sample, detector signal-to-noise ratios, laser amplitude noise control, and the digitization and buffering of the data stream are also discussed.

Computers↗