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Biomedical subjects

R C Noble

Publications and source records attributed to R C Noble.

At least 91 records · Page 5Linked to original sources
PubMed1985

The metabolism of palmitic acid in the fetal lamb.

[1-14C]Palmitic and [9,10-3H]palmitic acids were injected into the femoral artery of fetal sheep in utero about one month preparturition. The experiment was terminated after 5, 15 or 30 min when the main tissues were removed for analysis of the lipid components. 5 min after injection of the label, most was recovered in the plasma but increasing amounts were recovered later in the liver and heart. Selective loss of 14C-label occurred such that in the plasma, 30 min after injection, the ratio of 3H:14C had changed from 1:1 to 8.4:1. Increasing amounts of the labelled lipid were recovered in esterified form with time after injection, and the 3H:14C ratio differed markedly in specific lipids and tissues. Most of the label was recovered in palmitic acid, but some was also present in myristic and octadecenoic acids. Some evidence was obtained that the latter may have been the delta 11-isomer, which was found in much greater amounts in fetal than maternal tissues. It appears that partial-oxidation and resynthesis of fatty acids occurs in a concerted manner at a rapid rate in fetal sheep. The phenomenon has important implications for the interpretation of the results of much previous work with fetal animals in vivo.

Animals↗
PubMed1985

Colonisation of the urethra with Streptococcus pneumoniae: a case report.

A 25 year old man developed mild urethritis and urethral colonisation with Streptococcus pneumoniae five days after a single orogenital sexual contact. The diagnosis was suspected because of the appearance of Gram positive diplococci in the urethral exudate. The incidence of urethral infection with S pneumoniae is not known. Pneumococci are unlikely to grow on the routine selective media used to identify Neisseria gonorrhoeae.

Adult↗
PubMed1985

Synthesis of C20 and C22 polyunsaturated fatty acids by the placenta of the sheep.

Incubation in vitro of sheep placental homogenates with [1-14C] oleic, linoleic and linolenic acids resulted in extensive amounts of radioactivity becoming associated with C20 and C22 polyunsaturated fatty acid products. The fatty acids of the fetal plasma displayed substantial levels of both C20 and C22 polyunsaturated fatty acids, including the n-9 eicosatrienoic fatty acid associated with essential fatty acid deficiency, but extremely low levels of linoleic and linolenic acids. A role for the placenta in the provision to the fetus of a range of C20 and C22 polyunsaturated fatty acids derived from C18 fatty acid precursors is implicated.

Animals↗
PubMed1985

Incorporation of linoleic and arachidonic acids into ovine placental phospholipids in vitro.

The incorporation of [1-14C]-linoleic acid and [1-14C]-arachidonic acid into the lipids of ovine placental homogenate was studied. Both fatty acids were incorporated mainly into the phospholipid fraction with much lower levels being found in the diacylglycerols and triacylglycerols, particularly when the substrate was [1-14C]-arachidonic acid. Within the phospholipid fraction, both substrates were incorporated largely into phosphatidic acid although significant levels of incorporation were found in the phosphatidylcholine, phosphatidylethanolamine and phosphatidylinositol fractions. The incorporation of [1-14C]-arachidonic acid into phosphatidylcholine was lower and into phosphatidylethanolamine and phosphatidylinositol was higher than those levels found when the substrate used was [1-14C]-linoleic acid. While some of the trienoic and tetraenoic, but not pentaenoic, desaturation products of [1-14C]-linoleic acid were detected in phosphatidylcholine and phosphatidylethanolamine, the highest levels of incorporation of these metabolites were into phosphatidic acid. Similarly, the pentaenoic products of [1-14C]-arachidonic acid were found mainly in phosphatidic acid although significantly higher levels were observed in phosphatidylcholine, phosphatidylethanolamine and phosphatidylinositol. The results suggest that in ovine placental tissue polyunsaturated fatty acids, whether supplied pre-formed or made available by desaturation and elongation processes, could potentially be incorporated into phospholipids by the de novo route via phosphatidic acid.

Animals↗
PubMed1985

Incorporation in vitro of 14C fatty acids into bovine sebaceous gland and dermal lipids.

A study has been made of the incorporation in vitro of 14C palmitic, oleic and linoleic acids into the skin lipids of cattle. Linoleic acid was incorporated into the triglyceride (triacylglycerol) fraction of the sebaceous gland lipid at a greater rate than palmitic and oleic acids. Its incorporation was much greater when presented as a free acid than when presented either as cholesteryl linoleate or linoleoyl lecithin. However, the ability of cholesteryl ester and phospholipid to make a substantial indirect contribution of linoleic acid to sebum triglyceride synthesis by hydrolytic release of fatty acid was indicated. The association between the observed preferential incorporation of linoleic acid into the sebum triglycerides and the uniquely unsaturated triglycerides found on the skin surface of cattle is discussed.

Animals↗
PubMed1984

Posttransfusion hepatitis A in a neonatal intensive care unit.

A single unit of infected blood transfused into 11 neonates resulted in a large multistate outbreak of 55 cases of hepatitis A, 35 of which were symptomatic. The person who donated the blood to the 11 neonates became ill with hepatitis A one week after the donation. Hepatitis A infection was then acquired by nurses and physicians having direct contact with the neonates and by parents and relatives. Three additional newborns who had not received transfusions with the infected unit also acquired hepatitis A. The neonates with hepatitis A were all asymptomatic. The attack rate in susceptible nurses was 16%; in susceptible physicians, 4%. A survey of the relatives of the 11 newborns who received transfusions revealed eight symptomatic cases of hepatitis A in 32 immediate family contacts, ie, mother, father, and siblings, with a resulting attack rate of 25% uncorrected for prior immunity. The setting of the neonatal intensive care unit appears to be ideal for the transmission of hepatitis A.

Adult↗
PubMed1984

A unique lipid pattern associated with the gall bladder bile of the chick embryo.

A study has been made of the lipid and fatty acid composition of the gall bladder bile of the chick embryo during the last week of incubation. The lipids and their fatty acid composition showed a unique pattern when compared to other animal species. Of the total lipid present, phospholipid accounted for less than half, and there were substantial proportions of both cholesteryl ester and triglyceride. In the cholesteryl ester, the proportion of which increased significantly over the last week of incubation, there was a very high level of oleic acid. The phospholipid contained a high level of arachidonic acid. The results are discussed in relation to observations on the biliary lipids of other animal species and the major features of the lipid metabolism of the chick embryo during the last week of incubation.

Animals↗
PubMed1984

The positional distributions of fatty acids in the triacylglycerols and phosphatidylcholines of the intestinal and popliteal lymph and plasma of sheep.

As part of a study of the contribution of the intestinal lymph lipoproteins and their lipid constituents to the plasma lipids in sheep, the positional distributions of the fatty acids in the triacyl-sn-glycerols and phosphatidylcholines in very low density/low density lipoprotein and high-density lipoprotein fractions were determined by stereospecific analysis procedures. The triacyl-sn-glycerols of these lipoprotein fractions in intestinal lymph did not differ appreciably in structure and resembled the plasma triacyl-sn-glycerols in the composition of position sn-2 especially. However, there were appreciable amounts of the essential fatty acid, linoleic acid, in positions sn-1 and sn-3 of the triacylglycerols in lymph but not in plasma. This result is discussed in terms of the metabolism of the triacylglycerols of lymph after they enter the plasma as part of a mechanism for the conservation of essential fatty acids in ruminants. No differences of metabolic note were observed in the structures of the phosphatidylcholines between lipoprotein fractions and among tissues.

Animals↗
PubMed1984

The lipid composition of ovine placental tissue homogenate and its subcellular fractions.

Homogenates of the placental tissue of near term sheep were separated by differential centrifugation into mitochondrial, microsomal and cytosolic fractions. The relative proportions of the major neutral lipids and phospholipids, together with their fatty acid compositions, were determined in the homogenates and in each subcellular fraction. The cytosolic fraction contained the highest proportion of cholesteryl esters (CEs) and these possessed a fatty acid composition markedly different from the total CEs extracted from the homogenate. Both the mitochondrial and microsomal fractions contained significant proportions of solvent front phospholipid (SFP) and whereas the mitochondrial SFP displayed the relatively unsaturated fatty acid composition characteristic of diphosphatidylglycerol (cardiolipin), the fatty acids of the microsomal SFP were distinctly more saturated. These results are compared with those obtained from other mammalian tissues, both ruminant and non-ruminant, and discussed in terms of the function of the components of the subcellular fractions.

Animals↗
PubMed1984

A nursery outbreak of multiple-aminoglycoside-resistant Escherichia coli.

In the neonatal intensive care unit (NICU) of one hospital, 16 infants became colonized or infected with multiply-resistant Escherichia coli (MR-E.coli) over an 8-month period. Isolates were obtained from blood, urine, and sputum of three patients and from rectal surveillance cultures of 13 patients. The one patient with the blood isolate died. A matched case-control study identified continuous feeding (nine of 16 cases vs. one of 16 controls, p less than or equal to 0.001) and receipt of aminoglycosides (p less than or equal to 0.03) as risk factors. For case-babies not exposed to continuous feeding, duration of bolus feeding was significantly greater than for their controls (cases, 22 days; controls, 7 days; p less than or equal to 0.02). All 16 isolates were the same serotype and were resistant to amikacin, tobramycin, kanamycin, and gentamicin. The epidemiologic investigation suggested that MR-E. coli may have spread from person-to-person on the hands of personnel and that MR-E. coli persisted in the NICU for 8 months until effective control measures were instituted.

Aminoglycosides↗
PubMed1984

Miliary pulmonary blastomycosis.

Five patients with proved blastomycosis had a diffuse miliary nodular pattern seen on chest radiographs. These cases are presented to emphasize that blastomycosis may be the cause of a miliary pattern in an endemic area. Documentation requires recovery of the organism from body fluids or tissue since skin and serologic testing are unreliable indicators of active disease. With prompt diagnosis and appropriate treatment, the patient may recover from this form of endogenous disseminated reinfection that otherwise may be fatal, particularly in the immunocompromised host.

Adult↗
PubMed1984

The synthesis and accumulation of cholesteryl esters by the developing embryo of the domestic fowl.

A comparative study has been made of the accumulation and synthesis of cholesteryl esters in the liver, yolk sac membrane, and yolk contents of the chick embryo during the last week of development. This involved a comparison of the cholesteryl esters synthesized during incubation in vitro with 14C-cholesterol with those accumulated during incubation in vivo. Results indicated that the considerable accumulation of cholesteryl esters, mainly cholesteryl oleate, that occurred within the liver during embryo development arose from synthesis in the yolk sac membrane. This suggested a specific role in the transport of yolk lipid into the embryo. With the approach of hatching the ability of the liver to synthesize its own cholesteryl esters increased while that of the yolk sac membrane decreased.

Animals↗
PubMed1984

Lipid composition of the bovine epidermis.

In contrast to skin surface or sebum lipid, cattle epidermis was found to contain a lower proportion of wax ester and unesterified fatty acid and a high proportion of triglyceride. The epidermal triglycerides differed significantly in their fatty acid composition from those of the skin surface and sebum. In particular they contained extremely low levels of linoleic acid. It is concluded that the skin surface triglycerides and most likely the other major lipid fractions of the bovine skin surface are derived mainly from sebum.

Animals↗
PubMed1983

The characterization of the linoleic acid desaturation and elongation system in ovine placental tissue.

The desaturation and elongation of linoleic acid has been studied in homogenates and in subfractions of ovine placental tissue. The reaction was characterized in terms of pH and temperature optima, time course and protein concentration. Activity was found to be confined to the 11,000 g supernatant fraction of the tissue and the results suggest that the enzymes are membrane bound. The cytosolic fraction and ATP were required for full activity and the reaction was inhibited by cyanide. The properties of the reaction are compared with those of other desaturation systems and their implications with regard to possible reaction mechanisms are discussed.

Animals↗
PubMed1983

The colorimetric estimation of protein by the Lowry technique using a liquid scintillation counter.

A comparison has been made of the use of the spectrophotometer and liquid scintillation counter for the colorimetric quantification of protein. The attenuation of photon detection from sealed miniature 14C radioactive standards enabled protein quantification over a concentration range far in excess of that achievable by the use of a spectrophotometer. Accuracy of quantification was high over the entire range of protein concentration. The ability of the technique to provide quick and accurate protein estimations is discussed.

Colorimetry↗
PubMed1983

Ineffectiveness of annual chest roentgenograms in tuberculin skin test-positive hospital employees.

Annual routine chest x-ray examinations have been recommended for many years for tuberculin skin test-positive hospital employees who have not received chemoprophylaxis. To examine the case-finding effectiveness of this policy in a university teaching hospital, employee health records covering an 18-year period were reviewed. Pulmonary tuberculosis was diagnosed in four employees during that time period. None of the patients were identified through the routine annual chest x-ray examination. In the study institution the policy requiring routine annual chest x-ray examinations for tuberculin-positive hospital employees who had not received preventive therapy was rescinded. Currently, the first chest x-ray examination is required at the time of skin test conversion, the second 1 year after conversion, and the third 2 years after conversion. Health teaching and counseling regarding the symptoms of tuberculosis have been initiated for tuberculin-positive hospital employees.

Adult↗
PubMed1983

A comparative study of the distribution and fatty acid composition of the lipoproteins in the fetal and maternal plasma of sheep.

Fetal plasma contained significantly lower amounts of lipoproteins than the mother. In both mother and fetus, high density lipoprotein (HDL) was the major fraction. Very low density lipoprotein (VLDL) accounted for 12% of total plasma lipid in the mother but only 4% in the fetus. Maternal and fetal plasmas showed similar distributions of lipids in their HDL and low density lipoprotein (LDL) with cholesteryl esters comprising the major lipid of both and LDL having a higher level of triglycerides and lower level of phospholipids than HDL. Low levels of triglycerides were present in fetal VLDL. There were pronounced increases in levels of unsaturated fatty acids with increasing lipoprotein density. In the mother, levels of linoleic acid increased and in the fetus palmitoleic and oleic acids increased. The major saturated fatty acids in the fetal lipoproteins was palmitic acid and in the maternal lipoproteins stearic acid. In contrast to the mother, LDL and HDL of the fetus showed similar fatty acid compositions.

Animals↗