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Biomedical subjects

R J Henderson

Publications and source records attributed to R J Henderson.

At least 19 recordsLinked to original sources
PubMed1992

A study of catecholamine concentrations in selected renal segments of cats of different ages.

Renal concentrations of the catecholamine neurotransmitters norepinephrine (NE) and dopamine (DA) in 19 cats were measured by reverse-phase high pressure liquid chromatography (HPLC) with electrochemical detection. Animals of five different age groups (2-4, 6-8, 10-12 and 16-20 weeks and adult animals one year and older) were anesthetized and the kidneys were excised, sectioned into cortical, outer medullary and inner medullary segments, and processed for HPLC. There were no statistical differences in cortical NE concentrations between the 2-4 week and adult age groups, suggesting that peak noradrenergic nerve terminal density in the cortex is achieved at or before 2-4 weeks of age. NE concentration in the outer medulla and DA concentration in the cortex and outer medulla increased from the 2-4 to the 10-12 week age group but did not change significantly in the older animals. There were significant decreases in inner medullary NE and DA concentrations from the 10-12-week to the 16-20 week age group. The decrease in concentration of inner medullary catecholamines in the early postnatal period is consistent with the reported total loss of tyrosine hydroxylase- and dopamine beta hydroxylase-immunoreactive inner medullary nerve terminals at approximately 12 weeks of age.

Aging↗
PubMed1992

Preliminary characterization of the lipid and protein components of the protective surface membranes of a pentastomid Porocephalus crotali.

All instars of the pentastomid Porocephalus crotali, in the tissues of rat intermediate hosts and the lung of rattlesnake definitive hosts, are covered by a vesicular or stacked membranous secretory product which is synthesized in sub-parietal cells (SPC) and channelled to the cuticle via multitudinous chitin-lined ducts. In rats this enveloping foam of vesicles survives for the duration of a cuticle. We have purified and partially characterized the lipid and protein composition of lamellate droplets from SPC of infective nymphs. Lipids in the droplets comprised a mixture of neutral and polar lipid classes with cholesterol being the major neutral lipid and phosphatidylcholine the dominant polar lipid. In addition, Triton X-114 phase separation of the protein component of droplets partitioned these into an aqueous phase (with a major band at 60 kDa), a detergent phase with two hydrophobic polypeptides (24 and 16 kDa) and an insoluble pellet containing several minor proteins and major bands at 31 and 107 kDa. Western blotting, with rabbit anti-lamellate droplet antiserum, strongly label only the 60 kDa and the two hydrophobic proteins. Significantly no proteins at all label with serum from infected rats from 50-150 days post-infection, a finding endorsed by indirect fluorescent antibody tests on sectioned V-VII stage nymphs. Possible immunomodulatory functions of SPC-derived surface membranes are discussed and, in this regard, they are compared with pulmonary surfactant, a product of alveolar Type II cells which lines all vertebrate lungs.

Animals↗
PubMed1989

Catecholamine-containing, dopamine-beta-hydroxylase-immunoreactive perivascular nerve specializations in the rat kidney.

Fluorescence histochemical visualization of catecholamines and immunolabeling of dopamine beta hydroxylase (DBH) were employed to study noradrenergic nerve terminals and perivascular nerve specializations in the rat kidney. Plexuses of catecholamine-containing and dopamine-beta-hydroxylase-immunoreactive nerves innervate the intrarenal arterial tree and larger intrarenal veins. Some perivascular nerve bundles have specialized segments composed of clusters of axonal enlargements that are immunoreactive for DBH and fluoresce intensely in ultraviolet light after fixation in a solution of formaldehyde and glutaraldehyde or treatment with glyoxylic acid. No fluorescent neural structures were found in denervated rat kidney sections treated with glyoxylic acid. Many such structures are associated with arteriolar branches of interlobar, arcuate, and interlobular arteries and are composed, in part, of axonal enlargements that contain mitochondria, microtubules, and one or more clusters of synaptic vesicles. These perivascular nerve specializations may be sites of axoaxonal interactions between noradrenergic axons or between these axons and other types of autonomic or sensory axons. The synaptic vesicles evidently store large amounts of catecholamine, but there is no evidence whether it is released into the surrounding tissue. These structures may be involved in changes in intrarenal innervation patterns which may occur as the rat ages. Regardless of the autonomic or sensory nature of intrarenal neural structures, close association of most such structures with arterioles suggests some neurovascular interaction.

Animals↗
PubMed1988

The incidence of cancer following total hip replacement.

We have studied the incidence of tumours at remote sites following total hip replacement: 1,358 individuals have been followed up for 14,286 person-years after operation. In the decade following implantation the incidence of tumours of the lymphatic and haemopoietic systems was significantly greater, and that of cancer of the breast, colon, and rectum, significantly less than expected. Whilst the association might be due in part to an effect of the prosthetic implants, other mechanisms, particularly drug therapy, require consideration.

Breast Neoplasms↗
PubMed1986

The role of polyunsaturated fatty acids in fish.

The physical properties of polyunsaturated and saturated fatty acids are compared in relation to melting points and fluidity. The role of polyunsaturated fatty acids on membrane fluidity and membrane bound enzyme activity is discussed. The influence of the environment, particularly temperature, on poikilothermic animals is considered in relation to membrane fatty acid composition and metabolism. The metabolic role of polyunsaturated fatty acids of the (n-3) series and their interaction with arachidonate metabolism is discussed.

Animals↗
PubMed1985

Chain-length specificities of mitochondrial and peroxisomal beta-oxidation of fatty acids in livers of rainbow trout (Salmo gairdneri).

Peroxisomes and mitochondria were prepared from livers of rainbow trout fed diets containing either 15% crude fish oil (CFO) or 11.5% partially hydrogenated fish oil (PHFO) plus 3.5% CFO. Peroxisomal preparations from the two dietary groups showed similar rates and substrate specificity patterns for acyl-CoA oxidation. The peroxisomal oxidation rate was highest with 12:0-CoA and decreased with increasing chain length, being negligible with 22-carbon acyl-CoA's. The trans isomer of 18:1(n-9) was oxidized at a higher rate than the cis isomer only by peroxisomes from the PHFO + CFO group. Mitochondria prepared from both groups of fish exhibited a broad chain-length specificity for the oxidation of acylcarnitines. Both polyunsaturated and trans monoenoic fatty acids were readily oxidized.

Acyl Coenzyme A↗
PubMed1985

Changes in the fatty acid composition of phospholipids from turbot (Scophthalmus maximus) in relation to dietary polyunsaturated fatty acid deficiencies.

Young turbot (1-20 g) were maintained for not less than 14 weeks on three diets: (1) a control diet containing normal amounts of polyunsaturated fatty acids (PUFA); (2) a diet totally deficient in PUFA; (3) a diet deficient in the (n-6) series of PUFA but containing (n-3) PUFA. At 14 weeks the fatty acid compositions of the phospholipids from liver, gut, gills and muscle were analysed. Large changes in the amounts of PUFA in the phospholipids were found. Fish maintained on the totally PUFA deficient diet 2 had retained arachidonic acid, 20:4(n-6), and docosahexaenoic acid, 22:6(n-3), at the expense of eicosapentaenoic acid, 20:5(n-3). Fish maintained on the (n-6) PUFA-deficient diet (3) contained decreased amounts of 20:4(n-6) and 22:6(n-3) while retaining 20:5(n-3). In all cases phosphatidylinositol had the lowest n-3/n-6 ratios. These results are discussed in terms of PUFA function.

Animals↗
PubMed1979

Positional distribution of exogenous and endogenous fatty acids in triacylglycerols formed by rat adipocytes in vitro.

Rat adipocytes were used in vitro to compare the positional distributions of fatty acids of intra- and extra-cellular origin in triacyl-sn-glycerols. Fatty acids of extracellular origin were esterified to each position in similar, but not identical, proportions to the natural distributions. A high proportion of the oleic acid synthesised in the tissue by desaturation of exogenous stearic acid was found in position sn-3. When palmitic acid was the only fatty acid added, tripalmitoylglycerol was synthesised by the adipocytes. The rate and pattern of fatty acids synthesised de novo from acetate was dependent on the age of the donor rat and the concentration of acetate and presence or absence of long-chain fatty acids in the medium. The newly synthesised fatty acids were esterified in very different proportions from the natural distributions and thus from those of extracellular fatty acids. The results are discussed in terms of esterification of the fatty acids from the two sources in different compartments of the cell.

Adipose Tissue↗
PubMed1979

Esterification of exogenous and endogenous fatty acids by rat adipocytes in vitro.

Rat adipocytes were used in vivo to compare the esterification of exogenous fatty acids and fatty acids formed de novo from glucose or acetate. Pure single fatty acids added to the medium were esterified at comparable rates but marked differences were observed when the same acids were supplied as components of a fatty acid mixture of a composition similar to that in the tissue. Fatty acids synthesised de novo from acetate by adipocytes in a medium containing high concentrations of acetate were located predominantly in diacylglycerols. The effect was most marked with adipocytes from older rats and was enhanced by the presence of exogenous long-chain fatty acids. Exogenous oleic acid was esterified predominantly into triacylglycerols at all concentrations of acetate. No such accumulation of endogenously-synthesised fatty acids in diacylglycerols occurred when glucose was the precursor for fatty acid synthesis. The diacylglycerols formed were almost entirely of the sn-1,2-configuration.

Acetates↗
PubMed1979

Ribonucleic acid in plasma from normal adults and multiple myeloma patients.

Reports of the presence of RNA in human plasma have been numerous, often suggesting that RNA in plasma is correlated with human disease. We critically examined the methods for determination of RNA in plasma. Lack of method specificity has caused previous workers to overestimate plasma RNA concentrations by more than 50-fold. To isolate RNA from plasma, we used both a phenol-chloroform extraction and a modified Schmidt-Thannhauser procedure. We show that RNA in plasma can be identified and quantified by alkaline hydrolysis of the plasma extract and subsequent separation of the resulting 2'- and 3'-mononucleotides by "high-performance" liquid chromatography. We could not detect RNA in plasma from either apparently healthy, normal adults or multiple myeloma patients, but found 1.1 mg/L in the plasma of a patient with Waldenström's macroglobulinemia. Our method is useful for the specific determination of RNA in plasma and will detect as little as 600 micrograms/L.

Chromatography, High Pressure Liquid↗
PubMed1976

Correlation between serological and immunofluorescence results in the investigation of brucellosis in veterinary surgeons.

Four serological tests and three immunofluorescence tests for IgG, IgM, and IgA were compared for value in the investigation of brucellosis in veterinary surgeons. No one serological test stood out over the others, and the immunofluorescence tests did not appear to have advantages over the serological tests. If a laboratory is limited in time and resources then the saline agglutination or the complement fixation test would be reasonably satisfactory. The 2-mercaptoethanol test and the antihuman globulin (Coombs' test) have no advantages over the other two and could be dropped. Immunofluorescence tests are not recommended for routine testing of brucellosis sera. The results and these recommendations apply to the 'vet' sera tested; it is reasonable to suppose that what applies to 'vet' sera will also apply to sera of those who work with or are in repeated contact with cattle and who will have had previous experience of brucella antigen, that is, dairy farmers, herdsmen, or slaughter house employees.

Agglutination Tests↗
PubMed1975

Brucellosis and veterinary surgeons.

Forty-six veterinary surgeons were given a full clinical examination, serological examinations with estimates of immunoglobulins, and supplementary haematological and radiological investigations. Thirty-five complained of one or more symptoms, and eight had abnormal physical signs which might have been caused by infection with Brucella abortus, but neither sereological tests results nor immunoglobulin estimates bore any special relation to the clinical features. The soundest way of assessing ill health which had possibly been caused by brucellosis seemed to be thorough clinical examination and disregard of serologican findings. Interpreting results by the usual serological tests in the absence of a clinical examination is probably of doubtful value and may even be misleading.

Adult↗