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R B Howard

Publications and source records attributed to R B Howard.

88 records · Page 5Linked to original sources
PubMed1973

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PubMed1973

The fine structure, potassium content, and respiratory activity of isolated rat liver parenchymal cells prepared by improved enzymatic techniques.

Further modifications of the enzymatic technique for the preparation of isolated, intact, parenchymal cells from rat liver as previously described by this laboratory are presented together with a detailed account of several critical factors involved during the procedure. In addition, the fine structure of the cells as revealed by electron microscopy and the characteristics of their respiratory activity in different media and with several added substrates are described. It is shown that cells obtained by adding calcium during the preparative procedure retain approximately 34% more potassium than cells prepared solely in a calcium-free medium. The former cells also demonstrate a higher respiratory activity, which is not due to uncoupling of respiration. Electron microscopy reveals that the cells have an intact plasma membrane and well-preserved intracellular organelles. Glycogen particles are observed in all cells and are particularly abundant when either 20 mM pyruvate is added during the preparation or Eagle's Minimum Essential Medium is employed.

Animals↗
PubMed1967

The enzymatic preparation of isolated intact parenchymal cells from rat liver.

Suspensions of isolated parenchymal cells were prepared from rat liver by incubation with collagenase and hyaluronidase followed by mechanical treatment. Utilization of 0.15% collagenase together with 0.15% hyaluronidase yielded adequate numbers of cells for experimental purposes. As shown by light and electron microscopy, approximately 75% of the isolated cells retain their structural integrity. The cell suspensions are capable of maintaining endogenous respiration in the presence of 1% albumin for periods of time up to 8 hr. These cell preparations consist almost entirely of parenchymal cells and offer a unique tissue preparation for the study of hepatic metabolism.

Animals↗
PubMedDate not supplied

Pathogenetic considerations of pica in lead poisoning.

An important factor associated with lead poisoning in children is the habit of eating non-food substances, a condition termed pica. In search for underlying mechanisms involved in the pathogenesis of pica, this investigation presents evidence in support of the hypothesis that in many families failure of normal mother-child interaction, paternal deprivation, culturally dependent maternal oral interests and significant stress factors in the home where abundant lead-containing material is available are etiologically related to the development of pica in lead poisoning. Other factors, which have been thought to be associated with pica, are nutritional deficiencies and maladaptive behavior patterns. A multifocal treatment approach is considered to be most effective.

Child↗
PubMedDate not supplied

Extracellular flush solution that contains blood, mannitol, albumin, and prostacyclin protects rat lungs from six hours of ischemia.

We have used an isolated rat lung model to compare the quality of preservation of different flush techniques with each other and with topical cooling alone. Lung injury was assessed by recording lung weights after reperfusion after 4 and 6 hours of ischemia. The flush solutions studied were intracellular (Collins-Sacks), traditional extracellular, extracellular with low potassium plus dextran, and extracellular containing blood, mannitol, albumin, and prostacyclin (Wallwork's solution). Flushing with Wallwork's solution before both 4 and 6 hours of ischemia gave superior protection from lung edema after reperfusion over all the other methods.

Albumins↗