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J Ingram

Publications and source records attributed to J Ingram.

51 records · Page 3Linked to original sources
PubMed1982

Physician reimbursement.

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Blue Cross Blue Shield Insurance Plans↗
PubMed1981

Microvillar membrane neutral endopeptidases.

Recent developments on neutral endopeptidase (NEP, EC 3.4.24.11) are described. These include (1) the development of a novel colorimetric assay with a chromogenic substrate (Glutaryl-Gly-Gly-Phe-2-naphthylamide) coupled with aminopeptidase M (EC 3.4.11.2). (2) A detergent form of the pig kidney enzyme has been purified by immuno-adsorbent chromatography and its molecular properties compared with other forms of the enzyme from rabbit kidney and pig intestine. (3) Rat kidney microvilli contain two endopeptidases of about equal activity when assayed with [125I]iodo-insulin B chain as substrate. One is similar to the rabbit and pig endopeptidases in being sensitive to inhibition by phosphoamidon. The other is insensitive to the inhibitor, though susceptible to chelating agents. The two enzymes are resolvable and have been partially characterized. (4) Endopeptidases of the phosphoramidon-sensitive type are present in various tissues in addition to the principal locations in brush borders of kidney and intestine.

Aminopeptidases↗
PubMed1980

Proteins of the kidney microvillar membrane. Aspartate aminopeptidase: purification by immunoadsorbent chromatography and properties of the detergent- and proteinase-solubilized forms.

Aminopeptidase A (aspartate aminopeptidase, EC 3.4.11.7) was purified 2000-fold from pig kidney cortex. The essential step in the purification was chromatography on an immunoadsorbent column prepared from a rabbit antiserum raised against pig intestinal aminopeptidase A. Glutamyl and aspartyl substrate were attacked most rapidly and their hydrolyses were stimulated by Ca2+. The 2-naphthylamide derivatives of neutral and basic amino acids were also hydrolysed by aminopeptidase A, but at rates about two orders of magnitude lower, and Ca2+ was inhibitory. The possibility that these atypical substrates were hydrolysed by traces of aminopeptidase M (EC 3.4.11.2) contaminating the preparation could be excluded on several grounds. Aminopeptidase A was sensitive to inhibition by chelating agents and the inactive enzyme could be reactivated by Ca2+ or Mn2+. Atomic absorption spectrophotometry revealed 1 g-atom of Ca/143000 g of protein. Two forms of the enzyme were purified: an amphipathic form solubilized from the membrane by Triton X-100 (detergent form) and a hydrophilic form released by incubation with trypsin (proteinase form). The detergent form exhibited charge-shift in crossed immunoelectrophoresis when anionic or cationic detergents were present. On gel filtration, mol.wts. of 350000--400000 and 270000 were calculated for the detergent and proteinase forms. Electron microscopy after negative staining of the proteinase form revealed a dimeric structure. Electrophoresis of either form in the presence of sodium dodecyl sulphate revealed four polypeptides with mobilities corresponding to apparent mol.wts. of 155000, 110000, 90000 and 45000. All four bands stained positively for carbohydrate. Pig serum possesses weak aminopeptidase A activity; immunological experiments showed it to be a similar protein.

Aminopeptidases↗
PubMed1980

Reduction of amphotericin resistance in stationary phase cultures of Candida albicans by treatment with enzymes.

The resistance of Candida albicans to amphotericin B methyl ester increases rapidly as cultures enter the stationary phase of growth; organisms harvested after several days in the stationary phase may have a resistance two or three orders of magnitude greater than that of exponentially growing organisms. This resistance is decreased by incubation of the organisms with enzymes which attack components of the cell wall. Of the enzymes tested, (1 leads to 3)-beta-D-glucanases are the most effective; incubation of 7 d batch cultures with exo-(1 leads to 3)-beta-D-glucanase at a concentration of 10 microgram enzyme protein (mg dry wt organisms)-1 for 24 h at 37 degrees C and pH 6.5 reduces the resistance of the organisms to a value approximating to that of exponentially growing organisms. Resistance is also decreased by treatment with chitinase, lipase, trypsin, alpha-mannosidase and (1 leads to 6)-beta-D-glucanases but, on a specific activity basis, none of these enzymes is as effective as (1 leads to 3)-beta-D-glucanase. The action of (1 leads to 3)-beta-D-glucanase is markedly enhanced by the addition during incubation of chitinase, trypsin or lipase.

Amphotericin B↗
PubMed1979

Isolation of cholera toxin receptors from a mouse fibroblast and lymphoid cell line by immune precipitation.

Cholera toxin receptors have been isolated from both a mouse fibroblast (Balbc/3T3) and mouse lymphoid cell line labeled by the galactose oxidase borotritiide technique. Tritiated receptor-toxin complexes solubilized in NP40 were isolated by addition of toxin antibody followed by a protein A-containing strain of Staphylococcus aureus. In both cell types by far the major species of toxin receptor isolated was ganglioside in nature, although galactoproteins were also present in the immune complexes. Whether the galactoproteins form part of a toxin-receptor complex or are artifacts of the isolation procedure is presently unclear. The relative specificity of cholera toxin for a carbohydrate sequence in a glycolipid suggests that the toxin might prove a useful tool in establishing the function and organization of glycolipids in membranes. For example, interaction of cholera toxin with the mouse lymphoid cell line was shown to result in patching and capping of bound toxin, raising the possibility that the glycolipid receptor interacts indirectly with cytoskeletal elements. Cholera toxin might also be used to select for mutant fibroblasts lacking the toxin receptor and therefore having an altered glycolipid profile. Such mutants might prove useful in establishing the relationship (if any) between modified glycolipid pattern and other aspects of the transformed phenotype. Attempts to isolate mutants, based on the expectation that growth of cells containing the toxin receptor would be inhibited by the increase in cAMP levels normally induced by cholera toxin, proved unsuccessful. Cholera toxin failed to inhibit significantly the growth of either Balbc or Swiss 3T3 mouse fibroblasts although it markedly elevated cAMP levels.

Animals↗
PubMed1978

Exogenous progestogen and estrogen implicated in birth defects.

A five-year study of possible teratogenicity of exogenous female sex hormones included three case-control studies and one cohort study. The first case-control study disclosed an estimated relative risk of 8.41 and a highly significant difference in maternal hormonal exposure (P less than .001) between controls and infants with three major anomalies of the VACTERL group (V, vertebral; A, anal; C, cardiac; T, tracheal; E, esophageal; R, renal; and L,limb). Relative risk (RR) estimates of 5.58 (P = .017) and 3.35 (P less than .001) were found in two case-control studies involving maternal hormonal exposure and patients with congenital heart lesions without other malformations. A controlled, single-blind prospective study disclosed an excess of patients with major malformations (RR = 2.75), congenital heart anomalies (RR = 6), and neurological and neural tube disorders preponderant in the presence of a precipitously declining exposure rate during a three-year period in our referral area.

Abnormalities, Drug-Induced↗
PubMed1976

Dipeptidyl peptidase IV, a kidney brush-border serine peptidase.

Dipeptidyl peptidase IV, an enzyme that releases dipeptides from substrates with N-terminal sequences of the forms X-Pro-Y or X-Ala-Y, was purified 300-fold from pig kidney cortex. The kidney is the main source of the enzyme, where it is one of the major microvillus-membrane proteins. Several other tissues contained demonstrable activity against the usual assay substrate glycylproline 2-naphthylamide. In the small intestine this activity was greatly enriched in the microvillus fraction. In all tissues examined, the activity was extremely sensitive to inhibition by di-isopropyl phosphorofluoridate (Dip-F), but relatively resistant to inhibition by phenylmethylsulphonyl fluoride. It is a serine proteinase which may be covalently labelled with [32P]Dip-F, and is the only enzyme of this class in the microvillus membrane. The apparent subunit mol.wt. estimated by sodium dodecyl-sulphate/polyacrylamide-gel electrophoresis and by titration with [32P]Dip-F was 130 000. Gel-filtration and sedimentation-equilibrium methods gave values in the region of 280 000, which is consistent with a dimeric structure, a conclusion supported by electron micrographs of the purified enzyme. Among other well-characterized serine proteinases, this enzyme is unique in its membrane location and its large subunit size. Investigation of the mode of attack of the peptidase on oligopeptides revealed that it could hydrolyse certain N-blocked peptides, e.g. Z-Gly-Pro-Leu-Gly-Pro. In this respect it is acting as an endopeptidase and as such may merit reclassification and renaming as microvillus-membrane serine peptidase.

Animals↗
PubMed1975

The effect of intramuscular salbutamol in asthmatics.

1 In a double-blind placebo controlled dose-response experiment in six asthmatic patients with reversible airways obstruction the effect of i.m. salbutamol (4 mug/kg, 8 mug/kg or 12 mug/kg) was assessed by improvement in spirometry and change in pulse rate. 2 Salbutamol (8 mug/kg) resulted in a mean increase in FEV1 of 1 litre and a mean increase in pulse rate of 7 beats/minute. 3 It was concluded that salbutamol (8 mug/kg) was the optimal dose.

Adult↗
PubMed1975

Functional role of antibody against "core" glycolipid of Enterobacteriaceae.

Antibodies against the "core" glycolipid of Enterobacteriaceae (2-keto, 3-deoxyoctonate-Lipid A) have been associated with protection against the sequelae of gram-negative rod bacteremia. To investigate the nature of this protection, dogs and rabbits were immunized with purified glycolipid prepared by phenol-chloroform-petroleum ether extraction of the "Re" mutant of Salmonella minnesota 595 and opsonophagocytic and bactericidal tests were carried out using lapine peritoneal granulocytes and serum factors. Whereas 1-4 mug/kg of glycolipid i.v. produced hypotension in dogs and 8 mug/kg i.v. was lethal, a rising dosage schedule of immunization with an average total dose of 1 mg/kg produced striking protection against shock and death against challenge with heterologous organisms. 20 control dogs, given approximately 10(10) live, serum-resistant Escherichia coli 0.85:H9 or Serratia marcescens 03 during a continuous intra-arterial pressure transducer recording, showed a drop in mean systolic pressure from 186 (+/- 6 SE) to 101 (+/- 12 SE) MM Hg and a fall in mean diastolic pressure from 118 (+/- 3 SE) to 64 (+/- 8 SE) mm Hg within 60-120 min. Minor pressure changes (average less than 12% of prechallenge levels) were seen in the same number of immunized dogs. In contrast, no significant difference was noted in the bloodstream clearance of these serum-resistant organisms over a period of 4-6 h between immunized and control dogs. Intravascular clearance was greater in animals immunized with the challenged strain or in glycolipid-immunized animals challenged with highly serum-sensitive E. coli 0.14:K7. Antibody against core glycolipid protected against the hemodynamic sequelae of bacillemia, augmented intravascular clearance of serum-sensitive organisms, and abrogated the pyrogenic response to enteric bacilli, but did not enhance clearance of serum-resistant organisms. Although canine and lapine antiserum against core glycolipid passively protected mice against a heterologous challenge, opsonophagocytic and bactericidal activity was at least 100-fold less than type-specific antiserum.

Animals↗
PubMedDate not supplied

Avoiding the risk of needlestick injuries.

It is dangerous not to recap used needles, yet it can be equally dangerous to recap them. For each of us in the health sector, the prevention of needlestick injury (NSI) should be an everyday objective. This article discusses the risks associated with NSIs and examines whether current recommendations are being ignored.

Accidents, Occupational↗