Search PubMed⌕ Search

Biomedical subjects

R Henry

Publications and source records attributed to R Henry.

At least 19 recordsLinked to original sources
PubMed1995

A chloroplast homologue of the signal recognition particle subunit SRP54 is involved in the posttranslational integration of a protein into thylakoid membranes.

The mechanisms involved in the integration of proteins into the thylakoid membrane are largely unknown. However, many of the steps of this process for the light-harvesting chlorophyll a/b protein (LHCP) have been described and reconstituted in vitro. LHCP is synthesized as a precursor in the cytosol and posttranslationally imported into chloroplasts. Upon translocation across the envelope membranes, the N-terminal transit peptide is cleaved, and the apoprotein is assembled into a soluble "transit complex" and then integrated into the thylakoid membrane via three transmembrane helices. Here we show that 54CP, a chloroplast homologue of the 54-kDa subunit of the mammalian signal recognition particle (SRP54), is essential for transit complex formation, is present in the complex, and is required for LHCP integration into the thylakoid membrane. Our data indicate that 54CP functions posttranslationally as a molecular chaperone and potentially pilots LHCP to the thylakoids. These results demonstrate that one of several pathways for protein routing to the thylakoids is homologous to the SRP pathway and point to a common evolutionary origin for the protein transport systems of the endoplasmic reticulum and the thylakoid membrane.

Animals↗
PubMed1995

Influence of bile salt molecular species on cholesterol crystallization from supersaturated model biles.

Time-sequential enzymatic determination of cholesterol (CH) crystals harvested by ultrafiltration, and concomitant polarizing light microscopy observations corroborated the striking importance of the bile salts (BS) species in determining CH crystals formation rate from supersaturated model biles incubated in vitro. The more hydrophilic tauroursodeoxycholate, taurohyocholate, glycohyocholate, taurohyodeoxycholate, glycohyodeoxycholate and glyco-3 alpha, hydroxy-6 oxo-5 beta-cholanate inhibited CH precipitation through the formation of a stabilized liquid-crystalline phase. In contrast, in all hydrophobic systems (taurine (T) and glycine (G) conjugates of cholate (C), deoxycholate (DC) and chenodeoxycholate (CDC)), CH crystals precipitated with time. When crystallized CH concentrations were plotted vs. time, the figures showed a sigmoidal pattern, consistent with the transition from metastable systems to stable equilibrium states. Over the equilibration period, the nucleation kinetics (as inferred from enzymatic measurements) and all crystallization events (as microscopically observed) were both shifted in time, depending on the BS species: they were earliest in CDC systems, then in DC systems, and finally in C systems. In the latter, the delay was clearly due to the formation of a transient labile liquid-crystalline phase. G-conjugation also induced a significant delay in CH precipitation, compared to T-conjugation. At last, maximum crystallized CH concentrations at equilibrium were in the decreasing order: C > CDC > DC and T-conjugates > G-homologues. All data are discussed in connection with BS hydrophobicities, with predictions from the phase equilibria of aqueous biliary lipid systems and with new insights into CH crystal habits.

Bile↗
PubMed1995

Delayed diagnosis of cystic fibrosis in children with a rare genotype (delta F508/R117H).

OBJECTIVE: In neonatal screening for cystic fibrosis (CF), infants recognised as delta F508 heterozygotes require a sweat test to confirm the diagnosis. However, compound heterozygotes with delta F508 and the R117H mutation are known to have non-diagnostic sweat chlorides (< 60 mmol/L) at an early age. As genotyping for rare mutations is not readily available in Australia, there is a need to determine whether quantitative pancreatic stimulation tests could facilitate the diagnosis of CF in three infants with the delta F508/R117H mutation. METHODOLOGY: Formal sweat testing, genotyping and pancreatic stimulation tests were performed in three subjects heterozygous for delta F508 who initially had non-diagnostic sweat chloride results (40-60 mmol/L) but presented later with persisting chest symptoms and/or signs consistent with CF. RESULTS: All three patients were shown to have the delta F508/R117H genotype with initial sweat chloride results ranging from 40 to 58 mmol/L. Pancreatic stimulation tests demonstrated reduced enzyme secretion in two and decreased fluid, bicarbonate and chloride secretion in all three patients. CONCLUSIONS: In infants recognized as delta F508 heterozygotes by the newborn screening programme, the presence of an equivocal sweat chloride does not exclude the diagnosis of CF. If such patients with an initially equivocal sweat chloride subsequently develop symptoms suggestive of CF and have a persisting non-diagnostic sweat chloride then the diagnosis of CF can be confirmed by more extensive genotyping if available or by pancreatic stimulation testing.

Child, Preschool↗
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↗
PubMed1992

Statistical analysis of trends in urban ozone air quality.

The purpose of this paper is to demonstrate the use of some statistical methods for examining trends in ambient ozone air quality downwind of major urban areas. To this end, daily maximum 1-hr ozone concentrations measured over New Jersey, metropolitan New York City and Connecticut for the period 1980 to 1989 were assembled and analyzed. This paper discusses the application of the bootstrap method, extreme value statistics and a nonparametric test for evaluating trends in urban ozone air quality. The results indicate that although there is an improvement in ozone air quality downwind of New York City, there has been little change in ozone levels upwind of New York City during this ten-year period.

Air Pollutants↗
PubMed1992

A national model of faculty development in addiction medicine.

Increasing the number of faculty with expertise in addiction medicine is one of the challenges facing the medical community in the 1990s. To meet this challenge, the Society of Teachers of Family Medicine created a faculty development course to increase the expertise of family practice faculty involved in teaching residents. The authors describe the development, implementation, and consequences of the five-day intensive course that was taught to 165 participants at ten sites in 1990. The participants' self-reporting before and three months after the course showed significant increases in the numbers of participants who taught addiction medicine in eight of 11 clinical situations. The authors conclude that the course represents a model of faculty development in addiction medicine that is applicable to other specialties and health professions.

Evaluation Studies as Topic↗
PubMed1992

The management of acute laryngo-tracheo-bronchitis (croup): a consensus view.

The management of croup relies upon the traditional clinical skills of observation and examination. Parental involvement is essential and the appropriate reassurance of the patient is important. Endotracheal intubation is required only in a small percentage of children whose airway is compromised to such a degree as to produce fatigue and/or near occlusion.

Adrenal Cortex Hormones↗
PubMed1992

Comparison by race of total serum IgG, IgA, and IgM with CD4+ T-cell counts in North American persons infected with the human immunodeficiency virus type 1.

European patients with human immunodeficiency virus type 1 (HIV-1) infection have been reported to have lower titers of anti-p24 antibody than Central African HIV seropositive patients. Recently, black HIV positive patients in the United States were reported to be more likely to have detectable anti-p24 antibodies, less p24 antigenemia, and higher combined serum immunoglobulins than white HIV positive patients. We measured individual total serum immunoglobulins in 853 HIV positive patients (94% male; 58% white and 42% black) on their initial medical evaluation and compared them with CD4+ T-cell counts. Blacks had notably higher IgG levels (p = 0.001) across the entire spectrum of CD4+ T-cell counts. Serum IgM levels were slightly higher in blacks. IgA levels were not significantly different between the races, although the trend (p = 0.006) was toward higher levels in whites. We also measured these three serum immunoglobulins in 60 HIV seronegative, healthy blood donors (30 black and 30 white). In this control group, blacks had statistically higher IgG and IgA levels than whites. A review of the literature prior to the HIV/acquired immune deficiency syndrome epidemic also supports the view that racial differences in IgG levels are not specific for HIV infection. We speculate that racial differences in humoral immunity, independent of geography or strain of HIV, may account for differences in anti-HIV antibody levels and HIV antigenemia.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Gas chromatography-mass spectrometry and gas chromatography-tandem mass spectrometry of cyclic fatty acid monomers isolated from heated fats.

The analysis of hydrogenated cyclic fatty acid monomers isolated from heated linseed and sunflower oils is achieved by gas chromatography-tandem mass spectrometry of their pentafluorobenzyl esters. Collisionally activated dissociation of the carboxylate anions produced by electron-capture ionization shows remote charge-site fragmentation that allows location of cyclopentane and cyclohexane rings by examining the resulting mass-analysed ion kinetic energy spectra. Oxidative ozonolysis of the methyl esters of the unsaturated cyclic fatty acid monomers allows location of some double bonds. However, preliminary results obtained with remote charge fragmentation of synthetic unsaturated models make this approach an alternative for double bond location in the cyclic fatty acid monomers isolated from heated fats.

Cyclopentanes↗
PubMed1991

Psychological frailness and strength in an AIDS-affected community: a study of seropositive gay men and voluntary caregivers.

Addressed both the psychological frailness and strength in an AIDS-affected community. The gay community in Sydney, Australia, was represented by men who were seropositive (n = 60) and voluntary caregivers (n = 60). They were compared with two samples of men outside the gay community, who were ill with non-AIDS-related medical conditions (n = 30), and well (n = 30). Their psychological frailness and strength were measured by content analysis scales. Both the seropositive men and the caregivers showed the frailness of anxiety, indirectly expressed anger and helplessness, but also the compensating strength of greater personal competence and good feeling relative to the other men. The men who were seropositive or had other illnesses showed the predicted frailness of anxiety and depression but neither indirectly expressed anger nor helplessness. The seropositive men and caregivers of the gay community differed from each other only in the high levels of depression of the former.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Ion-pair high-performance liquid chromatography of bile salt conjugates: application to pig bile.

The high-performance liquid chromatographic separation and quantitation of conjugated bile salts from pig bile is reported. Synthetic standards and bile samples were chromatographed on a C18 reversed phase column using acetonitrile/water/tetrabutyl ammonium phosphate as an isocratic mobile phase at a flow rate of 1 mL/min. Detection of the ion-pairs was at 214 nm. The method permits efficient separation of all conjugated pig biliary bile salts without prior modification or treatment of the samples. Analysis of 12 pig biles showed that 85% of the bile salts are conjugated to glycine. The three main conjugated bile salts were glyco-3 alpha,6 alpha,7 alpha-trihydroxy-5 beta-cholanoic acid (GHC), glyco-3 alpha,7 alpha-dihydroxy-5 beta-cholanoic acid (GCDC), and glyco-3 alpha,6 alpha-dihydroxy-5 beta-cholanoic acid (GHDC). Glyco-3 alpha-hydroxy-6-oxo-5 beta-cholanoic acid (G3 alpha 6oxo), tauro-3 alpha,7 alpha-dihydroxy-5 beta-cholanoic acid (TCDC), tauro-3 alpha,6 alpha,7 alpha-trihydroxy-5 beta-cholanoic acid (THC), and tauro-3 alpha,6 alpha-dihydroxy-5 beta-cholanoic acid (THDC) were found to contribute each for 4 to 5% to the total. An excellent correlation was found between the sum of conjugated bile salts quantitated by high-performance liquid chromatography (HPLC) and values obtained by conventional enzymatic assay. Simplicity, efficiency and relative rapidity of the method render it suitable for routine analyses.

Animals↗
PubMed1991

The effect of ricin B chain on the intracellular trafficking of an A chain immunotoxin.

Covalent linkage of the A chain of ricin to the LICR-LOND-Fib75 monoclonal antibody produced an immunotoxin, Fib75-SS-ricin A, which demonstrated immunospecific toxicity to human bladder carcinoma cells in tissue culture (Forrester et al., 1984). The present studies have shown that ricin B chain potentiates the toxicity of the immunotoxin by two orders of magnitude and also significantly increases the rate of protein synthesis inhibition. Using immunoelectron microscopy, the receptor-mediated endocytosis and intracellular routing of the immunotoxin was studied with and without ricin B chain treatment after immunolocalisation of the conjugate. Fib75-SS-ricin A was internalised by the EJ cells predominantly in uncoated pits and vesicles and directed to the endosomes. Some degradation of the complex appeared to take place in multivesicular endosomes at early timepoints and 24 h after internalisation, most of the immunotoxin was found in lysosomes. Some ricin A chain epitopes were detected in Golgi vesicles. Cells treated with immunotoxin and ricin B chain endocytosed the complex predominantly in coated pits and coated vesicles. Using pre-embedding immunoperoxidase techniques, ricin chains were found in the whole Golgi complex and most of the conjugate escaped lysosomal degradation. Internalised immunotoxin was recycled back to the plasma membrane in an active form associated with vesicles which appeared to be derived predominantly from multivesicular endosomes. A similar mode of recycling has recently been reported (McIntosh et al., 1990) for ricin holotoxin in the same cell line. These observations may explain the potentiating effect of toxin B chains in the antibody-directed targeting of toxin A chains.

Antibodies, Monoclonal↗
PubMed1991

Assessment and treatment of childhood asthma.

In June 1990 a meeting of Paediatric Respiratory Physicians was held near Adelaide. The guidelines for assessing and treating asthma as prepared by the Thoracic Society of Australia and New Zealand for the management of patients with asthma was considered. Although not explicitly stated, these guidelines were designed for adult asthmatics. There was complete agreement that a companion statement was needed to take into account differences between the management of children and adults. This document fulfils that role. Further recommendations are found in a statement prepared by Australian and New Zealand respiratory paediatricians following a workshop in June 1989. This present statement should be read in association with the previous documents.

Asthma↗
PubMed1991

Survival after neonatal myocardial infarction.

These are case reports of two children with structurally normal hearts and with normal coronary arteries, who survived myocardial infarction in the early neonatal period. They are only the third and fourth reported survivors of neonatal myocardial infarction and the first in which hypercholesterolemia is postulated to have played an important role. The most likely cause of the myocardial infarction was thrombosis or thromboembolism. Changes in hemostatic function associated with hypercholesterolemia may be relevant.

Coronary Angiography↗
PubMed1990

Diurnal cardiovascular patterns in spontaneously hypertensive and Wistar-Kyoto rats.

This study was designed to determine whether diurnal patterns of blood pressure, heart rate, or locomotor activity differed among two substrains of Wistar-Kyoto rats, derived originally from Charles River or Taconic Farms stock, or the spontaneously hypertensive rat. Cardiovascular parameters were continuously monitored over 24 hours. Resting systolic and diastolic blood pressure values were statistically different among the three groups both during the lights-on (rest) and lights-off (active) phases of the cycle with blood pressure of spontaneously hypertensive rats greater than that of Wistar-Kyoto rats from Taconic Farms, which was greater than that of Wistar-Kyoto rats from Charles River. The largest difference in arterial pressure between Wistar-Kyoto/Taconic Farms and Wistar-Kyoto/Charles River was during the lights-on period. Heart rates of all rats decreased during the lights-on period; Wistar-Kyoto/Charles River had the largest decrease (-70 +/- 5 beats/min), Wistar-Kyoto/Taconic Farms had the least (-17 +/- 2 beats/min), and in spontaneously hypertensive rats the decrease was intermediate (-29 +/- 3 beats/min). The pronounced diurnal variation in pressure and heart rate exhibited by Wistar-Kyoto/Charles River was not present in either Wistar-Kyoto/Taconic Farms or spontaneously hypertensive rats. Blood pressure magnitude correlated with locomotor activity during both periods, although all groups showed minimal activity during the rest period. Observed differences between Wistar-Kyoto/Charles River and Wistar-Kyoto/Taconic Farms were not due to a lack of or an abnormality in baroreceptor reflex function.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗