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Biomedical subjects

D E Clark

Publications and source records attributed to D E Clark.

At least 145 records · Page 8Linked to original sources
PubMed1977

Technique for sampling subcutaneous fat from the tailhead of sheep.

Previously reported fat biopsy techniques (either omental or subcutaneous) require extensive restraint of the animal, require anesthesia methods, are time-consuming to do, or demand much postoperative care. The biopsy technique reported in the present paper involves the subcutaneous fat located around the tailhead of sheep. With minimal restraint of the sheep and local anesthesia, up to 1 g of subcutaneous fat can be obtained using this surgical procedure. Michel clips facilitate closure of the surgical wound, making this method brief in operative time.

Adipose Tissue↗
PubMed1976

Synthesis of a nonreducible cyclic analog of somatostatin having only growth hormone release inhibiting activity.

A nonreducible cyclic analog of somatostatin (SRIF) was prepared by a combination of solid phase and solution peptide synthesis. The compound, gamma-Abu-Lys-Asn-Phe-Phe-Trp-Lys-Thr-Phe-Thr-Ser-Asp-OH, was tested for its effect on the release of growth hormone, glucagon and insulin in rats. It significantly suppressed pentobarbital-stimulated growth hormone release but showed no effect on arginine-stimulated glucagon or insulin release. The linear form, NH2-gamma-Abu-Lys-Asn-Phe-Phe-Trp-Lys-Thr-Phe-Thr-Ser-Asp-OH, was also prepared and tested in vivo. It was shown to have only slight activity.

Amino Acid Sequence↗
PubMed1976

Power spectral distribution of the masseter electromyogram from surface electrodes.

The power spectral distribution of an electromyogram offers a useful presentation of the myoelectric signal at any level of muscle activity. Various factors which may affect this distribution are considered. A computerized method for obtaining the power spectral distribution for masseter and a study of the effect of bite force and electrode position on this is described.

Adult↗
PubMed1976

A unique intracellular aberration related to hexachlorobenzene ingestion.

Liver of rats fed hexachlorobenzene (HCB) at concentrations of 1, 5, 10 and 25 ppm for 3 to 12 months was studied by electron microscopy. A unique hepatic cellular change that seemed related to HCB ingestion occurred in more than half of the rats given 5 ppm or more HCB. The changes appeared as degeneration of lipid vesicles into a form of autophagic vacuole or storage vesicle. Degeneration of the lipid vesicles appeared to be by autodigestion, i.e., by endoplasmic reticulum encapsulation and partial digestion in the manner typical of other autophagic vacuoles. It is postulated that autodigestion may represent a way for the cell to eliminate fat-stored HCB.

Animals↗
PubMed1975

Psychologic and neurologic consequences of partial and complete cerebral commissurotomy.

Preliminary psychologic testing was carried out on four patients who had undergone surgical sectioning of a portion or all of the corpus callosum and anterior commissure as a treatment for uncontrollable seizures. Results confirm earlier findings indicating the importance of the forebrain commissures in the interhemispheric exchange of a variety of sensory and motor information, and demonstrate that particular portions of the commissural system are responsible for transferring the information of specific sensory modalities. The patients also showed surprising abilities in performing complex tasks assumed to require integration of information from both hemispheres.

Adolescent↗
PubMed1975

Ultrastructural changes in liver of the rat fed hexachlorobenzene.

Changes in hepatic ultrastructure were observed in rats given hexachlorobenzene (HCB) as a component of the diet in concentrations of 5, 10, and 25 ppm for 3, 6, and 12 months. A significant change was in the cellular regions normally containing smooth endoplasmic reticulum (SER). Sometimes the SER proliferated and at other times it appeared to be replaced by quantities of storage product presumed to be glycogen. Proliferation of SER was often associated with the smaller doses of HCB and the increase in storage products with the larger doses of HCB. However, dose relationships were variable. The most significant changes were in mitochondria which became elongated or swollen. Swollen mitochondria were occasionally as large as nuclei. Usually only a fraction of the mitochondria in a cell appeared abnormal. Storage bodies 1 to 4 mum in diameter developed in some cells. These bodies were surrounded by a double membrane derived from the endoplasmic reticulum and may have been the partly digested remains of degenerated mitochondria.

Animals↗