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Biomedical subjects

R A Henry

Publications and source records attributed to R A Henry.

At least 19 recordsLinked to original sources
PubMed2002

Germ-line transformation of the Australian sheep blowfly Lucilia cuprina.

The Australian sheep blowfly, Lucilia cuprina, is the most important economic insect pest for the sheep industries in Australia and New Zealand. piggyBac-mediated germ-line transformation of L. cuprina was achieved with a helper plasmid that had the Drosophila melanogaster hsp70 promoter controlling expression of the transposase and a piggyBac vector with an EGFP marker gene. Two transformant lines were obtained, at a frequency of approximately 1-2% per fertile G0. One of these lines has a single copy of the transgene, the other most likely has four copies. This is the first report of germ-line transformation of L. cuprina and is an important step towards the generation of engineered strains that would be suitable for male-only release eradication/suppression programmes.

Animals↗
PubMed2001

Recruitment of the male-specific lethal (MSL) dosage compensation complex to an autosomally integrated roX chromatin entry site correlates with an increased expression of an adjacent reporter gene in male Drosophila.

Drosophila dosage compensate (equalize X-linked gene products) by doubling the transcription of most X-linked genes in males. The MSL (male-specific lethal) ribonucleoprotein complex consisting of at least five proteins and two non-coding RNAs (roX1 and roX2) is essential for this transcription response. Recently it has been shown that the X-linked roX1 and roX2 genes each contain at least one chromatin entry site for the MSL complex. In this study we show that insertion of either roX1 or roX2 DNA sequences, upstream of an insulated lacZ reporter gene controlled with the constitutive armadillo promoter (arm-lacZ), results in a significant elevation of expression of lacZ in males. However, full compensation, that is a precise doubling of lacZ expression in males relative to females, was only observed in some lines carrying autosomal insertions of either roX1-arm-lacZ or roX2-arm-lacZ transgenes. Furthermore, we found that a 419-base pair fragment of roX1 that contains an MSL binding site was sufficient to cause a modest elevation of expression of lacZ in males, but this response was significantly less than obtained with a full-length roX1 cDNA. This is the first direct demonstration that insertion of an MSL chromatin entry site on an autosome results in elevated expression in males of genes near the entry site.

Animals↗
PubMed1999

Development of an insulated reporter system to search for cis-acting DNA sequences required for dosage compensation in Drosophila.

Dosage compensation (equalization of X-linked gene products) occurs in Drosophila melanogaster by a two-fold transcriptional increase of X-linked gene expression in the male. The cis-acting X-linked DNA sequences required for dosage compensation (called DCREs) remain elusive, despite numerous attempts to identify them. We have developed an insulated reporter system to minimise problems previously encountered with identifying these elements. The system consists of the constitutive autosomal armadillo promoter fused to the lacZ reporter gene (called arm-lacZ) which was flanked by SCS insulator elements to block potential repressive effects of an autosomal chromatin environment. Seven X-linked DNA fragments, totaling 62.7 kb, were each inserted between the SCS element and the armadillo promoter. If an X-linked fragment contains a DCRE, then transgenic males carrying an autosomal insert of the construct should produce twice the beta-galactosidase activity of females. However, in all cases, males and females expressed the same level of lacZ. Thus, it's likely that none of the X-linked fragments contained a DCRE, suggesting these elements may be rarer than previously thought. The insulated reporter system was also used to test the hypothesis that some genes may be dosage compensated due to repression by Sex lethal (Sxl) in females. A fragment from the runt gene containing three Sxl binding sites was inserted into the 3' untranslated region of arm-lacZ. Transgenic males carrying an autosomal insert of the construct had on average 1.31-1.46 times the level of beta-galactosidase than females, suggesting that some genes could be compensated, at least partially, by Sxl repression in females.

Animals↗
PubMed1998

Interactions between CO2 chemoreflexes and arterial baroreflexes.

We studied interactions between CO2 chemoreflexes and arterial baroreflexes in 10 supine healthy young men and women. We measured vagal carotid baroreceptor-cardiac reflexes and steady-state fast Fourier transform R-R interval and photoplethysmographic arterial pressure power spectra at three arterial pressure levels (nitroprusside, saline, and phenylephrine infusions) and three end-tidal CO2 levels (3, 4, and 5%, fixed-frequency, large-tidal-volume breathing, CO2 plus O2). Our study supports three principal conclusions. First, although low levels of CO2 chemoreceptor stimulation reduce R-R intervals and R-R interval variability, statistical modeling suggests that this effect is indirect rather than direct and is mediated by reductions of arterial pressure. Second, reductions of R-R intervals during hypocapnia reflect simple shifting of vagally mediated carotid baroreflex responses on the R-R interval axis rather than changes of baroreflex gain, range, or operational point. Third, the influence of CO2 chemoreceptor stimulation on arterial pressure (and, derivatively, on R-R intervals and R-R interval variability) depends critically on baseline arterial pressure levels: chemoreceptor effects are smaller when pressure is low and larger when arterial pressure is high.

Adult↗
PubMed1995

Stimulation and binding of myocardial phospholipase C by phosphatidic acid.

Exposure of adult ventricular myocytes to exogenous natural phosphatidic acid results in the production of inositol phosphates by unknown mechanism(s). We characterized stimulation of myocytic phosphoinositide-specific phospholipase C (PLC) by synthetic dioleoyl phosphatidic acid (PA) as a potential mechanism for modulation of inositol phosphate production. Our data demonstrate that exogenous PA, at 10(-8)-10(-5) M, caused a concentration-dependent increase in inositol 1,4,5-trisphosphate in adult rabbit ventricular myocytes. PA also caused a concentration-dependent increase in in vitro activity of myocytic PLC in the presence or absence of ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA). PLC-delta 1, the predominant isozyme of PLC expressed in adult rabbit ventricular myocytes, bound to liposomes of PA with high affinity in the presence of EGTA. The phosphomonoester group of PA was critical to in vitro stimulation of myocytic PLC activity and high-affinity binding of PLC-delta 1. We propose that binding of PLC-delta 1 to phosphatidic acid may be a novel mechanism for dynamic membrane association and modulation of PLC in adult ventricular myocytes.

Animals↗
PubMed1988

Fathers in the cesarean section room and maternal/neonatal outcomes.

Two hundred twenty-seven consecutive full-term deliveries by cesarean section over a 10-month period were divided into "father present" and "father absent" groups. The father present group tended to have received prenatal care in the private office and to have experienced regional anesthesia more frequently. Apgar scores at one and five minutes were significantly higher when deliveries occurred with the fathers present. The time from skin incision to delivery of neonate was longer but the numbers of transfusions were significantly lower in the father present group. However, when the two groups were further analyzed controlling for anesthesia mode, the differences disappeared with the exception of higher Apgar scores at five minutes with father present and regional anesthesia. No adverse consequences were noted from fathers' presence.

Anesthesia, Obstetrical↗
PubMed1984

HCMR interviews physician administrator leaders. Interview by Michael J. Enright.

This interview departs from HCMR's usual format, interviewing several leaders in health care administration for their ideas on current economic pressures, the impact of competition and joint ventures, attitudes toward equity and capital formation, and competition between the interest of clinical medicine and the cost of care. The physician administrators interviewed hold senior administrative positions: Charles Edwards, President and Chief Executive Officer of Scripps Clinic and Research Foundation; Robert A. Henry, President and Chief Executive Officer of Swedish-American Corporation; William S. Kiser, Chairman of the Board of Governors at Cleveland Clinic Foundation; W. Eugene Mayberry, Chairman of the Board of Governors at Mayo Clinic; and Ronald P. Kaufman, Vice-President for Medical Affairs of George Washington University Hospital. All are members of the Board of Regents or Fellows of the American College of Physician Executives.

Economic Competition↗
PubMed1980

Lymphoid hypophysitis with selective adrenocorticotropic hormone deficiency.

This report describes a 31-year-old woman with evidences of selective adrenocorticotropic hormone deficiency associated with a remarkable pituitary lesion, lymphoid hypophysitis. Clinical manifestations of secondary hypocortisolism, which first appeared during the immediate postpartum period following normal pregnancy, included progressive weakness and mental aberrations, fasting hypoglycemia, transient hypercalcemia, and striking ECG changes. Sudden death resulted from cardiorespiratory collapse. Microscopic examination of the anterior pituitary disclosed focal fibrosis and extensive lymphocytic infiltrations with a marked reduction of basophils; immunostaining techniques demonstrated a selective loss of corticotropin-secreting cells. The histopathology of the pituitary and its association in this case with lymphoid thyroiditis suggest that selective damage to corticotrophs was due to an autoimmune process.

Adrenal Glands↗
PubMed1978

Distribution of the genus Leptospira in soil and water.

The distribution of the aerobic spirochetes Leptospira in surface waters, soil, and aquatic animals was investigated. Isolates from water and soil exhibited physiological characteristics common to members of the "biflexa complex," none were capable of infecting experimental animals, and leptospires could not be isolated from the eight genera of aquatic animals examined. The isolation frequencies from surface waters were: stream, 100%; lake, 65%; spring, 28%; bog lake, 5%; and marsh, 0%. With the exception of the stream, more isolations were obtained from the soil adjacent to the water than from the water. Leptospires were most frequently associated with soils of high moisture and organic matter content.

Amphibians↗
PubMed1973

Cultivation of parasitic leptospires: effect of pyruvate.

Sodium pyruvate (100 mug/ml) is a useful addition to the Tween 80-albumin medium for the cultivation of parasitic serotypes. It is most effective in promoting growth from small inocula and growth of the nutritionally fastidious serotypes.

Animals↗