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Biomedical subjects

T Gallagher

Publications and source records attributed to T Gallagher.

At least 55 records · Page 3Linked to original sources
PubMed1991

Comparison of the calf suckling technique and milk oxytocin test for estimation of milk yields.

The calf suckling technique and milk oxytocin test were compared as methods to quantify lactation yields in Sanga-type cows in the multi-purpose livestock sector of central Zambia. There was no significant difference between the overall means derived from 154 observations. The oxytocin method interferes less with the multi-purpose system of management, is less time consuming and does not require expensive calf weight scales.

Analysis of Variance↗
PubMed1990

Ultrastructure of hybrids derived from electric pulse fusion of human HeLa cells and murine 3T3.4E cells.

Somatic cell hybrids were obtained with electric pulse by fusion of human epithelial HeLa cells derived from uterine carcinoma and mouse fibroblasts 3T3.4E, deficient in thymidine kinase. Hybrids were selected and propagated in HAT medium. After 3 passages the cultures were morphologically homogeneous. They retained an epithelial morphology. Electron microscopic and morphometric studies indicate that these hybrids at the 6th passage differed from parental cells. They exhibited the smallest cellular and cytoplasmic size. The number of mitochondria was similar to that of murine fibroblasts but their size was more homogeneously distributed; the mitochondria matrix was more electron dense than in the parental cells. These data suggest that these hybrids have a different metabolism from that of the parental cells; they contained modified mitochondria.

Animals↗
PubMed1989

Pyruvoyl-dependent histidine decarboxylase. Active site structure and mechanistic analysis.

The structure of the pyruvoyl-dependent histidine decarboxylase has been refined to 2.5 A resolution by the methods of x-ray crystallography from crystals grown at pH 4.8, where the enzyme is optimally active. Models of the active site with and without the bound substrate analog, histidine methyl ester (HisOMe), or the product, histamine, have been produced. Comparison of native and ligand-bound structures reveals no widespread differences in conformation but does reveal motion of a few key residues (Tyr-62', Ile-59', Ser-81) upon binding of HisOMe in the active site. The HisOMe binds with the appropriate alpha-carbon-carbon bond oriented as required to facilitate the formation of the transition state. The binding site contains two pockets, one for the imidazole group, and another for the -COOMe group. In the imidazole pocket, the imidazolium group forms hydrogen bonds with two neighboring carboxylates, Asp-63' and the carboxyl terminus of the beta chain, Ser-81. Hydrophobic contacts are also observed. The carboxylate pocket is predominantly hydrophobic as predicted by Alston and Abeles (Alston, T. A., and Abeles, R. H. (1987) Biochemistry 26,4082-4085), but includes one carboxyl group, that of Glu-197, about 3.5 A from the substrate carboxylate. If Glu-197 is protonated under these conditions, it could serve as the proton donor following decarboxylation; if it is ionized under these conditions, its carboxylate group is appropriately placed to enhance the lability of the substrate carboxylate ion by providing a "push" in promoting the flow of electrons that results in decarboxylation. These and other structural features of the binding complex are discussed as they relate to a proposed mechanism of decarboxylation.

Amino Acid Sequence↗
PubMed1989

Antigenic immunostaining patterns in somatic hybrids of human HeLa cells and mouse fibroblasts 3T3.4E propagated in conventional medium and delipidized serum.

Somatic cell hybrids were obtained with electric pulse by fusion of human epithelial HeLa cells derived from a carcinoma of the uterine cervix and mouse fibroblasts 3T3.4E, deficient in thymidine kinase. Hybrids were selected and propagated in HAT media; some experiments were carried out in medium with delipidized serum. The hybrid cells were characterized by indirect immunofluorescence with a biotin-streptavidin system using a panel of nine monoclonal antibodies specific for membrane and cytoplasmic antigens of parental cells: intermediate filaments (keratins and vimentin), HLA class 1 (beta 2-microglobulin), cell activation (EGF and transferrin receptors) and cellular adhesion (fibronectin and laminin). All of these antigens were expressed in HeLa cells cultured in conventional medium or with delipidized serum. Conversely mouse fibroblasts contained only vimentin, fibronectin and laminin. All the parental antigens were present in first passage hybrid cells cultured in conventional medium. Vimentin, fibronectin and laminin were maintained in fourth passage hybrids whereas keratins, beta 2-microglobulin, EGF and transferrin receptors were no longer detected. When propagated in medium with delipidized serum, hybrid cells re-expressed these antigens after 5 days of culture. These findings suggest that the reexpression of HeLa cell antigens in hybrid cells was related to deficiency in vitamin A.

Animals↗
PubMed1988

Persistence and expression of human papillomavirus during interferon therapy.

Alpha interferon did not prevent the persistence or expression of human papillomavirus (HPV) types 6 or 11 in respiratory tract papillomas. Seventeen patients receiving interferon therapy for a minimum of six months and a maximum of 39 months still had one to ten copies per cell genome of HPV DNA in their laryngeal tissues, seen by Southern blot hybridization. In papillomas that recurred during treatment, HPV RNA could be detected by in situ hybridization, and capsid protein could be detected by immunoperoxidase staining. Persistence of the HPV DNA, and recurrences that occurred during therapy, are attributed to the failure of interferon therapy to eliminate latent virus.

Antigens, Viral↗
PubMed1986

Infectious RNA derived by transcription from cloned cDNA copies of the genomic RNA of an insect virus.

RNA transcripts of cloned cDNA of the genomic RNAs of BBV (black beetle virus) are infectious to cultured cells of Drosophila melanogaster. Individual transcripts had approximately 10% of the infectivity of the corresponding authentic virion RNA. Progeny virus resulting from transcript infection was phenotypically indistinguishable from the progenitor virus used to generate the original cDNA forms as judged by sucrose density gradient sedimentation, specific infectivity, plaque morphology, and serology. Although the transcript RNAs used to produce this virus had 20 nonviral bases headed by a capping group at their 5' termini, these 20 bases were absent in the progeny viral RNAs. The cDNA forms, and therefore the resulting transcript RNAs, should be readily modifiable by the techniques of recombinant DNA technology both for viral studies and for the insertion of foreign genes into the viral genome and thus into the host cytoplasm.

Animals↗
PubMed1984

Presentation of malignancy by metastasis to the carpal navicular bone.

Although peripheral metastases of many malignancies to bone are common, metastases to the hand and carpus are rare. This is the first report of a silent primary malignancy of the lung presenting as a metastasis to the carpal navicular bone. Only eight instances of carpal bone metastases secondary to all tumor sources were revealed in a search of the literature. The presentation of metastatic disease in the hand in an occult malignancy may be deceptive, often mimicking pulp space infection, osteomyelitis, septic arthritis, gout, acute rheumatoid monoarticular arthritis, tenosynovitis, or sympathetic dystrophy. These lesions often present as radiolucent lesions; histologic findings are consistent with the tumor of origin. Treatment is palliative and consists of resection or amputation. Radiotherapy should be avoided in the hand due to secondary fibrosis and scarring.

Aged↗
PubMed1982

A comparison of dorsal and volar resting hand splints in the reduction of hypertonus.

Ten adults with hypertonic wrist flexors volunteered as subjects in an experiment comparing the effectiveness of dorsal and volar resting hand splints in the reduction of abnormal muscle tone. Subjects were randomly assigned to two groups of five each. Individuals in one group were fitted with dorsal splints, and individuals in a second group with volar splints. Measurements by spring-weighted scales were taken to assess the efficiency of each splint design in the reduction of hypertonus. Results demonstrated no significant differences between the volar and dorsal splints in reducing hypertonus. However, the age of the subjects was found to be an intervening variable: The older subjects of both groups demonstrated a gradual but not significant decline in hypertonus, whereas the younger adults demonstrated a significant decline in hypertonus over a 6-week period.

Adult↗