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Biomedical subjects

J Eng

Publications and source records attributed to J Eng.

At least 181 records · Page 10Linked to original sources
PubMed1982

Post-translational processing of cholecystokinin in pig brain and gut.

A sequential extraction method employing methanol extraction of the COOH-terminal fragments of cholecystokinin (CCK) from pig tissues followed by HCl extraction of intact CCK and its NH2-terminal fragments is described. Radioimmunoassay of extracts and their fractionation by Sephadex chromatography and HPLC demonstrate that the distributions of COOH-terminal and NH2-terminal immunoreactivities among various regions of brain are similar and independent of the concentrations in individual regions. The distribution in gut differs from that in brain. Greatest concentrations of CCK immunoreactivity are located in cortical tissue in the brain and in duodenal mucosa in gut. Both brain and gut contain CCK octapeptide (CCK8) and an NH2-terminal fragment that is likely to be desoctapeptide-CCK33. Intact CCK33 is extractable from gut but not from brain. Brain contains another NH2-terminal immunoreactive molecule lacking COOH-terminal immunoreactivity that may be a peptide with a COOH-terminal extension, as has been described for gastrin, or one that may not be derived from a CCK33-like precursor. This peptide is much less prominent in gut, or may be nonexistent there. The failure to find CCK33 in the brain and the presence in the brain of this as-yet-uncharacterized NH2-terminal peptide raises the question as to whether the differences between neuronal and mucosal tissues are a consequence of differences in post-translational processing or in the DNA templates.

Animals↗
PubMed1982

Absence of pork-like insulin in guinea pig tissues.

By using a technique for concentrating insulin 100-fold from tissue extracts with 75-95% recoveries, we earlier failed to detect pork-like insulin in guinea pig tissues and thus were unable to confirm reports from the National Institutes of Health that these tissues contain a pork-like insulin at concentrations averaging 1 ng/g. This difference could have been due to differences in strains of guinea pigs studied or in the species specificities of the antisera used for radioimmunoassay. In the current study, tissue extracts from both NIH and Hartley guinea pigs were assayed with three antisera routinely used in our laboratory and one antiserum that had been used in the National Institutes of Health laboratory. We observed that pork-like insulin in tissues from both strains of guinea pigs as determined with the four antisera is less than 0.02 ng/g. We therefore conclude that is is unlikely that nonpancreatic guinea pig tissues contain or synthesize a peptide resembling pork or other non-guinea pig mammalian insulin.

Animals↗
PubMed1982

A clinical laboratory evaluation of the vacutainer 20 ml tube for aerobic blood cultures.

Clinical blood cultures with made in parallel from the same venipuncture in two Vacutainer 20 ml tubes, each inoculated with 2 ml of blood, a 50 ml blood culture bottle with plain (normotonic) broth and a 50 ml bottle with hypertonic broth, each of the bottle media being inoculated with 4 ml of blood. Of a total of 127 sets of monomicrobic blood cultures, growth was obtained from 115 bottles with plain broth, 108 pairs of Vacutainer tubes and 105 bottles with hypertonic broth. The hypertonic broth medium proved superior to the Vacutainer tubes in the time required for isolation of gram-negative rods. No significant differences were observed between the results obtained from the Vacutainer tubes and those from the plain broth medium. Of the 108 cultures positive in the Vacutainer system, 19 cultures (17.6%) yielded growth from one of the tubes only. Because of the small volume of blood cultured, the Vacutainer 20 ml tube is not recommended for routine clinical blood cultures, with the exception of cultures taken from newborn infants in the diagnosis of neonatal septicaemia.

Bacteria↗
PubMed1982

Coreactivity of Legionella pneumophila immune sera in the Mycoplasma pneumoniae complement fixation test.

Sheep and guinea pigs were immunized with cellular and extracellular antigen from Legionella pneumophila bacteria. After immunization, the animals developed immunoglobulin G titers against the immunizing agent. The same sera were also tested in a Mycoplasma pneumoniae complement fixation test. All the preimmunization sera from sheep showed positive M. pneumoniae complement fixation tests of varying titers, with significant antibody rises in two of five sheep as a result of the Legionella immunizations. In contrast to the sheep, all the guinea pigs were negative in the M. pneumoniae complement fixation test, both in their preimmunization sera and after completion of the Legionella immunizations. The results obtained with the sheep sera may be explained as a nonspecific booster effect of Legionella bacteria upon previously elicited immune responses.

Animals↗
PubMed1982

Correlation of growth of aerobic blood cultures in hypertonic broth with antibiotic therapy.

The aim of this study was to elucidate the mechanisms by which sucrose improves growth in a hypertonic medium for isolating aerobes from blood. Clinical blood cultures were made routinely in duplicate in plain broth consisting of brain heart infusion broth with sodium polyanetholesulfonate, gelatin, and penicillinase and the same broth with 20% sucrose added. The growth patterns of Staphylococcus aureus and Enterobacteriaceae from plain and from hypertonic broth were correlated with the presence or absence of antimicrobial therapy in patients when the blood cultures were collected. In S. aureus bacteremias, 58.7% of the positive cultures collected during treatment of patients with beta-lactam antibiotics showed earlier growth or growth only in hypertonic broth, compared with 16.7% of the cultures taken during treatment with other antimicrobial agents (P less than 0.05) and 17.6% of the cultures made in antibiotic-free intervals (P less than 0.01). In the group of cultures yielding growth of Enterobacteriaceae, growth occurred earlier or solely in hypertonic broth in 28.9% of the cultures taken during treatment with beta-lactam antibiotics, compared with 15.7% of the cultures taken during treatment with other antimicrobial agents and 21.6% of the cultures collected in antibiotic-free intervals (differences not statistically significant). It is concluded that treatment with beta-lactam antibiotics is an important reason for the improved growth of S. aureus from hypertonic broth, but other factors are also involved.

Adolescent↗
PubMed1981

Peptide hormones in strange places--are they there?

Are ACTH and insulin synthesized in tissues other than the pituitary and pancreas, respectively? ACTH and TSH are widely distributed in the rat brain but are restricted to the hypothalamic regions of the primate brain. It is concluded that these pituitary peptides are not synthesized in the brain in extrahypothalamic sites. The apparent immunoreactive ACTH in pancreas and gastrointestinal tract does not have the physicochemical characteristics of any known form of ACTH and thus is probably an artifact of some radioimmunoassay systems. Concentrations of insulin in acid-ethanol extracts of brains of rats and some other animals are generally less than plasma concentrations while concentrations in kidney extracts are about ten-fold plasma levels. The use of octadecylsilyl silica cartridges permits up to a hundred-fold concentration of insulin in acid-ethanol tissue extracts with recoveries greater than 75--85 percent. With this methodology it is observed that pork-like insulin in guinea pig tissues is less than 20 pg/g in contrast to the ng/g levels reported by others. It is concluded that ACTH and insulin are not brain/gut peptides and that guinea pig tissues do not contain measurable pork-like insulin in several radioimmunoassay systems.

Adrenocorticotropic Hormone↗
PubMed1981

Nature of immunoreactive CCK in rat and pig brain.

Two major classes of immunoreactive cholecystokinin peptides (iCCK) have been identified in rat and pig brains: (1) large basic peptides (Big iCCK) resembling pCCK33 in size and charge; (2) small acidic peptides (Small iCCK) resembling the COOH-terminal fragments of CCK. Boiling 0.1 N HCl maximally extracts Big iCCK; boiling 0.1 N NaOH maximally extracts Small iCCK. The differences in hormonal forms removed by these extractions are not likely to be due to enzymatic conversion during the extraction procedures. Fractionation on Sephadex G50 and starch gel electrophoresis combined with radioimmunoassay using 3 antisera of different specificities: (1) directed towards the NH2-terminus of pCCK33; (2) produced by immunization with CCK8; (3) produced by immunization with CCK4; are consistent with the hypothesis that a major fraction of Big iCCK may represent intact CCK with a COOH-terminus extension as has recently been suggested for gastrin, a molecule having a COOH-terminal pentapeptide identical with that of CCK.

Animals↗
PubMed1981

Extraction and immunochemical characterization of cholecystokinin-like peptides from pig and rat brain.

Two major classes of immunoreactive cholecystokinin peptides (iCCK) have been identified in rat and pig brains: (i) large basic peptides (big iCCK) resembling the 33-amino acid porcine cholecystokinin (pCCK33) in size and charge; (ii) small acidic peptides (small iCCK) resembling the COOH-terminal fragments of CCK. Boiling 0.1 M HCl maximally extracts big iCCK; boiling 0.1 M NaOH maximally extracts small iCCK. The differences in hormonal forms removed by these extractants are not likely to be due to enzymatic conversion during the extraction procedures. Fractionation on Sephadex G-50 and starch gel electrophoresis combined with radioimmunoassay using three antisera of different specificities--(i) directed towards the NH2 terminus of pCCK33, (ii) produced by immunization with COOH-terminal fragment CCK8, (iii) produced by immunization with COOH-terminal fragment CCK4--are consistent with the hypothesis that a major fraction of big iCCK may represent intact cholecystokinin with a COOH-terminal extension, as has recently been suggested for gastrin, a molecule having a COOH-terminal pentapeptide identical with that of cholecystokinin.

Animals↗
PubMed1981

Evidence against extrapancreatic insulin synthesis.

Labeled and unlabeled insulin in acid/ethanol tissue extracts can be concentrated up to 100-fold by using a hydrophobic adsorption technique. After adsorption to and elution from an octadecylsilyl silica column, insulin is recovered in yields greater than 75%. By using this method of concentration, insulin in brain tissues of three of four fed rats and one rabbit was found to be less than 20% of plasma concentration. The kidney is the only extrapancreatic organ in which insulin is observed to be markedly above plasma levels. Porcine-insulin-like material was not detectable in guinea pig tissues (less than 0.02 ng/g). It is concluded that insulin is not synthesized in brain or other extrapancreatic tissues and that other mammalian insulins are not found in guinea pig tissues.

Animals↗
PubMed1981

Tobramycin therapy of serious infections. Pharmacological aspects and side effects.

Plasma concentrations and side effects were followed in 52 adults treated with tobramycin for 4-39 days (mean 12.2 days). In order to obtain 1-h peak levels above the recommended 4 microgram/ml in patients with normal renal function, loading doses of 160 mg followed by 100-120 mg every 8 h were usually necessary. Both the leading dose and the mean daily dose of 304 mg were higher than usually recommended. Great individual variations in doses required were found and nomograms were of little value. Reduced maintenance doses were given to patients with impaired renal function. Adequate treatment required plasma level determinations 2-3 times a week. The high dose of tobramycin regimen used in this study implied that 30% of the trough levels exceeded 2 microgram/ml. The frequency of clinically significant side effects were, however, low and the treatment was only interrupted once because of a decrease in renal function. Temporary reduction in renal function probably related to tobramycin was found in 6 patients, and 5 patients got temporary disturbances of vestibular function. One patient experienced a temporary hearing loss and 2 patients a permanent hearing loss, which might have been caused by simultaneous treatment with furosemide and tobramycin.

Adult↗
PubMed1981

Evaluation of sucrose and magnesium sulfate as additives in aerobic blood culture medium.

Clinical blood cultures were made in duplicate in brain heart infusion broth with sodium polyanetholsulfonate and gelatin (P broth) and in the same medium with 20% sucrose (S broth). In part of the study, 0.1% magnesium sulfate was also included in the medium with sucrose (SMg broth). The results from 1,287 positive blood cultures are reported. Significant differences among the rates and speeds of isolations from these media were found in Enterobacteriaceae and Staphylococcus aureus, which were isolated more frequently from S broth and SMg broth than from P broth; in addition, recoveries were accomplished earlier (1 or more days) from S broth and SMg broth than from P broth more often than the reverse growth patterns. An additional effect of magnesium sulfate upon recoveries could not be concluded. The possible mechanisms by which sucrose promotes recoveries from clinical blood cultures are discussed.

Aerobiosis↗
PubMed1981

Radioimmunoassay of leucine-enkephalin-like substance in human and canine plasma.

Fasting human plasma immunoreactive leu-enkephalin (ir-leu-enkephalin) measured by radioimmunoassay averages 54+/-10 pg/ml. The method depends on acidification of plasma to protect against destruction of the peptide, adsorption to XAD-2 resin, extraction from the resin by aqueous methanol and concentration by evaporation. Plasma enkephalin in the dog increased from 13 to 56 pg/ml following insulin-induced hypoglycemia.

Adult↗
PubMed1981

Alkaline extraction and characterization of cholecystokinin-immunoreactivity from rat gut.

Generally some variation of neutral or acid extractants has been used to recover immunoreactive cholecystokinin (CCK) from gut as well as from brain. Recovery of CCK in 0.1 N NaOH extracts from gut mucosa, gut muscle, or whole gut ranged up to threefold higher than in similar water or 0.1 N HCl extracts, although the reverse was the case for the extraction of secretin from the same tissue. CCK-immunoreactive peptides from rat gut were found to resemble a CCK-33-like peptide, sulfated CCK-12 and CCK-8, as well as smaller COOH-terminal fragments, which are larger than the C-terminal tetrapeptide amide. The fraction of immunoreactivity in the form of a CCK-33-like peptide was greater, although the total recovery was less, in acid extractants of whole gut. Proper interpretation of dynamic changes in gut CCK in response to fasting, feeding, and other laboratory manipulations requires efficient extraction of total immunoreactivity.

Animals↗