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Biomedical subjects

D Hillman

Publications and source records attributed to D Hillman.

At least 19 recordsLinked 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↗
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↗
PubMed1979

Hypothyroidism and anemia related to fluoride in dairy cattle.

Blood and urine were collected from 72 cows in six dairy herds with varying severity of dental and bone fluorotic lesions. Urinary fluoride averaged 5.13 ppm and ranged from 1.04 to 15.7 ppm fluoride. Thyroxine and triiodothyronine in serum decreased with increasing urinary fluoride, eosinophils increased, and cholesterol tended to decrease. Cattle afflicted with fluorosis developed hypothyroidism, anemia, and eosinophilia of leukocytes. Bone ash averaged 2400 ppm fluoride in 22 specimens from eight herds (range 850 to 6935 ppm fluoride). Mineral supplements were the main sources of excess fluoride. Fluoride lesions were on some cows of all herds suggesting that fluoride may affect the health and performance of some cows in "normal" herds. Fluoride lesions were on young cattle and calves in fluorosis herds.

Anemia↗
PubMed1978

Deformability characteristics of sickle cells by microelastimetry.

Deformability of normal and sickle erythrocytes was measured by means of micropipette elastimetry with determination of intrinsic membrane rigidity (P) and total cell deformability (Pt). In the elastimetric technique employed, negative pressure at the pipette tip was generated and measured continuously. Membrane rigidity is defined as the negative pressure, in mm H2O, required to induce a hemispherical projection of the cell surface into the micropipette, and total cell deformability as the negative pressure required to aspirate the entire cell into the pipette lumen. Membrane rgidity for oxygenated sickle discocytes was not statistically different from that of control normal discocytes, but Pt measurements were significantly higher for sickle than normal discocytes. Irreversibly sickled cells (ISCs) had markedly increased membrane rigidity and whole cell deformability when compared to control normal cells. Mildly deformed ISCs and severely deformed ISCs at ambient pO2, both showed significantly higher mean membrane rigidity values than sickle discocytes and reversibly sickled cells. Sickle and normal discocytes both showed membrane elasticity with reversion to original cell shape following release of the cell from its aspirated position at the pipette tip. ISCs, however, exhibited elastic deformation of the membrane. These studies provide further evidence of progressive alteration of the sickle cell membrane induced by the sickling-unsickling process, culminating in formation of the ISC, and suggest a role for the ISC membrane abnormality in the pathologic rheology of sickle cell disease.

Anemia, Sickle Cell↗