Search PubMed⌕ Search

Biomedical subjects

R Henry

Publications and source records attributed to R Henry.

At least 91 records · Page 5Linked to original sources
PubMed1995

A comparison of the gill physiology of two euryhaline crab species, Callinectes sapidus and Callinectes similis: energy production, transport-related enzymes and osmoregulation as a function of acclimation salinity

Callinectes sapidus and C. similis co-occur in estuarine waters above 15 salinity. Callinectes sapidus also inhabits more dilute waters, but C. similis is rarely found below 15 . Previous work suggests that C. sapidus may be a better hyperosmoregulator than C. similis. In this study, energy metabolism and the levels of transport-related enzymes in excised gills were used as indicators of adaptation to low salinity. Oxygen consumption rates and mitochondrial cytochrome content of excised gills increased in both species as acclimation salinity decreased, but to a significantly greater extent in C. similis gills. In addition, C. similis gills showed the same levels of carbonic anhydrase and Na+/K+-ATPase activities and the same degree of enzyme induction during low-salinity adaptation as has been reported for C. sapidus gills. However, hemolymph osmolality and ion concentrations were consistently lower in C. similis at low salinity than in C. sapidus. Therefore, although gills from low-salinity-acclimated C. similis have a higher oxygen consumption rate and more mitochondrial cytochromes than C. sapidus gills and the same level of transport-related enzymes, C. similis cannot homeostatically regulate their hemolymph to the same extent as C. sapidus.

Journal Article↗
PubMed1995

Macquarimicins, microbial metabolites from Micromonospora. II. Isolation and structural elucidation.

A novel series of carbocyclic compounds has been isolated from two related Micromonospora cultures. The C-19 and C-22 macquarimicins represent different end products on a similar biosynthetic scheme. 1-D and 2-D homonuclear and heteronuclear NMR experiments allowed assignment of the basic structures of the macquarimicins. An X-ray structure of macquarimicin B suggested the stereochemistry for the series which was not discernible from spectroscopic data alone.

Anti-Bacterial Agents↗
PubMed1995

Single-step protocol for preparation of plant tissue for analysis by PCR.

PCR has many applications in the isolation and analysis of plant DNA. The influence of salt and EDTA concentration, pH, incubation time and temperature on the preparation of plant material for PCR was evaluated. A general single-step method was developed in which a small amount of plant tissue was heated in a simple solution. The DNA in the supernatant was found to be suitable for most PCR applications including arbitrarily primed PCR (random-amplified polymorphic DNA) and PCR with specific primers for both single- and multiple-copy genes. The technique is much simpler than those generally used for plant DNA preparation and was successful with tissues from a wide range of species.

Base Sequence↗
PubMed1995

Intracardiac extension of a Wilms' tumour.

A case report is presented of a Wilms' tumour in a three-year-old child. Direct intravascular extension into the heart led to a fatal outcome. Though a rare complication, clinical suspicion, combined with appropriate investigation and management, should lead to salvage of such a patient.

Child, Preschool↗
PubMed1995

Myocardial perfusion scintigraphy using Tc99m labelled compounds: correlations with coronary angiography.

The increasing incidence of ischaemic heart disease with high mortality rate and the recent introduction of Tc99m labelled myocardial perfusion imaging agents, along with the advent of a Coronary Angiography programme in Trinidad and Tobago, prompted the comparison of the sensitivity and specificity of myocardial perfusion scintigraphy (MPS) with coronary angiography (CA). Using a standard one-day code-differential imaging protocol Single Photon Emission Computed Tomography (SPECT), images of the left ventricular myocardium of 30 patients were obtained at rest and following exercise: These images were analyzed for perfusion defects to assess each of the three main coronary arteries; the left anterior descending artery (LAD), the right coronary artery (RCA) and the left circumflex artery (LCx). The data were then correlated with the angiographic findings. MPS yielded an overall sensitivity of 97.5% and a specificity of 83.6% when compared to CA. Discordant data were obtained in the analysis of nine vascular territories with scintigraphy producing eight false positives and one false negative. The false positive cases were seen in two males and four females. Of the males, one was discovered to have intramyocardial tunnelling of the LAD artery and the other demonstrated differential perfusion between the LAD and LCx arteries. Of the females, one was classified as having Syndrome X and another demonstrated differential perfusion between the LAD and LCx arteries; the other two cases were attributed to breast attenuation. The one false negative was obtained in a patient who demonstrated good collateral circulation on angiography. MPS thus compares very well with CA in assessing the three main myocardial vascular territories.

Adult↗
PubMed1994

SecA homolog in protein transport within chloroplasts: evidence for endosymbiont-derived sorting.

The SecA protein is an essential, azide-sensitive component of the bacterial protein translocation machinery. A SecA protein homolog (CPSecA) now identified in pea chloroplasts was purified to homogeneity. CPSecA supported protein transport into thylakoids, the chloroplast internal membrane network, in an azide-sensitive fashion. Only one of three pathways for protein transport into thylakoids uses the CPSecA mechanism. The use of a bacteria-homologous mechanism in intrachloroplast protein transport provides evidence for conservative sorting of proteins within chloroplasts.

Adenosine Triphosphatases↗
PubMed1994

Differences between lumen targeting domains of chloroplast transit peptides determine pathway specificity for thylakoid transport.

Nuclear encoded thylakoid lumen proteins are imported into the chloroplast storma and further directed across thylakoid membranes by lumen targeting domains. Recently, we showed that there are two protein-specific pathways for transport into the lumen. This was unexpected in that lumen targeting domains have similar properties, all containing bacterial signal peptide motifs. Nevertheless, sequence homology analysis suggests that pathway specificity is determined by elements in the lumen targeting domain. To test this, we constructed and analyzed chimeric proteins in which transit peptides from proteins transported by one pathway were fused to the mature domains of proteins directed by the other. We also investigated the transport characteristics of a previously unexamined protein whose pathway was predicted by sequence similarity analysis. Our results confirm that lumen targeting domains contain pathway sorting elements and further indicate that distinct energy and stroma requirements for transport are pathway characteristics, unrelated to the passenger protein. These findings suggest the operation of two mechanistically different translocators.

Arabidopsis↗
PubMed1994

Role of human skeletal muscle insulin receptor kinase in the in vivo insulin resistance of noninsulin-dependent diabetes mellitus and obesity.

To assess the role of insulin receptor (IR) tyrosine kinase in human insulin resistance, we examined the kinase activity of IR of skeletal muscle biopsies from eight lean and five obese nondiabetics and six obese subjects with noninsulin-dependent diabetes mellitus (NIDDM). Biopsies were taken during euglycemic clamps at insulin infusion rates of 0, 40, 120, and 1200 mU/m2.min. IRs were immobilized on insulin agarose beads, and autophosphorylation and histone 2B phosphorylation were measured. Phosphatase and protease inhibitors preserved the in vivo phosphorylation state of the IRs. Glucose disposal rates (GDR) were reduced according to insulin dose by 23-30% in the obese (P < 0.05) and 43-64% in the NIDDM subjects (P < 0.0005). IR autophosphorylation was increased up to 9-fold in controls and was reduced (P = 0.04) in NIDDM compared to obese subjects. Histone-2B kinase was increased up to 6-fold in controls and was reduced by 50% in NIDDM. Kinase values by both methods were similar in lean and obese controls. In vivo stimulation of kinase was well correlated to the increase in GDR, as was the decrement in kinase in NIDDM to the decrement in GDR. These results suggest that defects in muscle IR kinase are significant in the in vivo insulin resistance of NIDDM, but not that of obesity.

Adult↗
PubMed1994

HIV-related training programs for health care professionals: findings from a collaborative assessment.

Seeking to avoid duplication of effort, evaluators from twelve separate HIV-related training programs worked together to share information, assessment tools, measurement instruments, and preliminary findings across programs. Each training program focused on preparing health care professionals to meet the growing demands of the AIDS epidemic and specifically address psychosocial issues of care. The collaborative effort of program evaluators included an examination of experiences across programs and yielded recommendations for needs assessments, process evaluation procedures, and outcome measures. This paper focuses on the findings from an analysis of needs assessments and process evaluations across twelve HIV-related training programs in eleven areas of the country.

Forecasting↗