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Biomedical subjects

J Kay

Publications and source records attributed to J Kay.

At least 217 records · Page 12Linked to original sources
PubMed1987

Sequestration of environmental cadmium by metallothionein in the roach (Rutilus rutilus) and the stone loach (Noemacheilus barbatulus).

Two species of coarse fish that are relatively resistant to cadmium poisoning were exposed to sub-lethal concentrations of the metal in their aquarium water. Thus, roach were exposed to cadmium concentrations between 30 and 500 micrograms/l for periods of 14-70 days whereas stone loach were exposed to 1250 micrograms Cd/l for 21-77 days. Under all conditions of exposure, it was found upon analysis of the major organs of accumulation of cadmium in the two species that the toxic metal was sequestered by a single isoform of metallothionein. The amino acid compositions of roach and stone loach metallothionein were determined and found to be similar to those reported for other piscine metallothioneins. The two proteins were found to contain Cd:Zn:Cu in approximate ratios of 4:1:2 per mole of protein. The sequestration of Cd by metallothionein in the two resistant species of fish is contrasted with the situation observed previously in a cadmium-sensitive species, the rainbow trout.

Amino Acids↗
PubMed1987

A cognitive neuropsychological case study of anomia. Implications for psychological models of word retrieval.

The case of a neurological patient with severe anomic word-finding difficulties is reported. A detailed cognitive neuropsychological investigation of the patient's ability to name objects to confrontation was carried out in an attempt to determine where his cognitive deficits might lie. In contrast to the findings of recent case studies of word-finding difficulty (e.g., Howard and Orchard-Lisle, 1984), it was observed that the patient seemed to have a clear understanding of the items that he was trying to name, suggesting that his problems in word-finding were not semantically based. Indeed, the patient would often generate partial phonological information about the sought-after word, indicating that he had a specific target in mind, and this was reminiscent of 'tip-of-the-tongue' states in normal word-finding. A difficulty in retrieving complete phonological forms of words is considered as the probable locus of his anomia. A distinction is made between semantically-based and phonologically-based anomias.

Anomia↗
PubMed1987

The effect of diffusion on the immunolocalization of antigen.

Diffusion prior to tissue fixation may result in immunohistochemical localization of antigen at sites in which it does not occur in vivo. The extent and speed with which this may occur have been investigated with several antigens of different molecular weights in tissues which were left unfixed for various lengths of time. There was clear evidence of diffusion when fixation was delayed for as little as 1 h, resulting in focal labelling of cells which did not contain antigen in rapidly fixed tissues. Falsely localized antigen was particularly evident adjacent to sites containing high antigen concentrations and might be expected in areas permeated by antigen-containing tissue fluid. These findings substantiate the view that diffusion of antigen should be considered as a cause of false positivity in any immunolocalization study.

Animals↗
PubMed1987

Alkaline proteinase localization in myoblasts.

Recent interest in elucidating the role of non-lysosomal proteases in intracellular protein catabolism in muscle has led to various investigations with three alkaline proteases: a trypsin-like, a chymotrypsin-like, and a high molecular weight cysteine proteinase. Although in vitro biochemical assays have revealed the catabolic potential of at least two of these proteases, confirmation of their presence in muscle cells has been difficult. In this study immunohistochemical techniques were employed to localize each of these proteases in rat myoblasts. Antisera against the trypsin-like and chymotrypsin-like proteinase (both serine proteinases) showed strong localization in the cytoplasm immediately around the nucleus. Both also stained chromatin material in the nucleus of these cells. Fluorescent localization of the high molecular weight cysteine proteinase (Proteinase I) also appeared to be cell-associated in the myoblasts. The use of myoblasts in cell culture sections of whole muscle was advantageous, since localization of the proteases could be assessed in the absence of other cell types.

Animals↗
PubMed1987

Slow moving proteinase. Isolation, characterization, and immunohistochemical localization in gastric mucosa.

Human gastric mucosa contains three immunochemically distinguishable aspartic proteinases, pepsinogen I (pepsinogen A), pepsinogen II (pepsinogen C, progastricsin), and a nonpepsinogen proteinase also termed slow moving proteinase (SMP). The properties of SMP, and in particular its relationship to another aspartic proteinase, cathepsin D, were examined in this study. Slow moving proteinase and cathepsin D were isolated, respectively, from gastric mucosa and human spleen. Antiserum specific to each proteinase was prepared in rabbits. Rabbit anti-SMP did not recognize cathepsin D, and conversely, anticathepsin D did not react with SMP. Immunohistochemical studies localized SMP to surface epithelial cells in both the fundic and pyloric gland areas of the stomach. In contrast, cathepsin D was found mainly in mononuclear cells in the lamina propria and in parietal cells. Slow moving proteinase exhibited considerably lower Km values for its interaction with two chromogenic substrates than did cathepsin D. An even greater distinction between the two enzymes was found with the protein inhibitor from Ascaris lumbricoides; the activity of SMP was inhibited very strongly, whereas that of cathepsin D was not affected. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis under denaturing conditions, SMP consisted of two subunits with apparent molecular weights of 42,500 and 41,000. The last two properties characterize a less-well-known aspartic proteinase, cathepsin E. We conclude that SMP is not cathepsin D, but that it may be cathepsin E.

Cathepsin D↗
PubMed1986

A systematic series of synthetic chromophoric substrates for aspartic proteinases.

The hydrolysis of the chromogenic peptide Pro-Thr-Glu-Phe-Phe(4-NO2)-Arg-Leu at the Phe-Phe(4-NO2) bond by nine aspartic proteinases of animal origin and seven enzymes from micro-organisms is described [Phe(4-NO2) is p-nitro-L-phenylalanine]. A further series of six peptides was synthesized in which the residue in the P3 position was systematically varied from hydrophobic to hydrophilic. The Phe-Phe(4-NO2) bond was established as the only peptide bond cleaved, and kinetic constants were obtained for the hydrolysis of these peptide substrates by a representative selection of aspartic proteinases of animal and microbial origin. The value of these water-soluble substrates for structure-function investigations is discussed.

Animals↗
PubMed1986

Immunogold electron-microscopic localisation of calpain I in skeletal muscle of rats.

By using a double-affinity-purified first antibody and colloidal gold-conjugated second antibody, it is shown that calpain I (a cysteine proteinase activated by micromolar concentrations of Ca2+) has a predominant intracellular location in the I-band region of the extensor digitorum longus (EDL) muscle of the rat, but is not exclusively associated with the Z-line.

Animals↗
PubMed1986

Effect of automatic blood pressure devices on vigilance of anesthesia residents.

The response time of anesthesia residents to interruption in auditory blood pressure monitoring was compared between two anesthesia training programs that have different blood pressure monitoring traditions. Program A relies exclusively on manual blood pressure cuffs, whereas program B uses automated blood pressure devices for approximately 90% of patients. In this limited, short-term study, the time that lapsed between interruption of auditory monitoring and recognition of the interruption was less in the program that used manual blood pressure cuffs. The impact of the automated blood pressure device on resident vigilance in anesthesia training programs may be negative.

Anesthesia↗
PubMed1986

A comparison of the differential accumulation of cadmium in the tissues of three species of freshwater fish, Salmo gairdneri, Rutilus rutilus and Noemacheilus barbatulus.

Roach and stone loach were exposed to cadmium dissolved in their aquarium water at 500 and 1250 micrograms/l, respectively, and the distribution of the metal accumulated in the major body organs was determined. The pattern of distribution for each species was somewhat different and was distinct in each case from that observed previously with rainbow trout. The total body loads of cadmium accumulated by the three species were assessed during the period of exposure and found not to correlate directly with the concentration of cadmium to which the individual species had been exposed. An alternative comparator was devised which as the quotient of the total body cadmium accumulation (microgram/100 g body wt) and the notional cadmium dose (microgram/l) X weeks was described as a fractional retention coefficient for cadmium. The coefficient was constant for each species at different periods of exposure to cadmium alone. The values of the coefficient for roach and stone loach were however much lower than that for rainbow trout. When rainbow trout were preexposed to zinc (100 micrograms/l, 5 days) before being exposed to cadmium, the fractional retention coefficient for cadmium fell to a value similar to those seen with roach and stone loach exposed to cadmium alone. The significance of these observations in relation to the nature of the intracellular proteins to which cadmium is bound in the three species is discussed in the light of their differential susceptibility to the toxic effects of cadmium.

Animals↗
PubMed1986

Immunolocalization of cathepsin D in normal and neoplastic human tissues.

The aspartic proteinase cathepsin D was purified from human spleen and localised in various formalin fixed paraffin embedded human tissues using the peroxidase-antiperoxidase (PAP) technique. Cathepsin D was shown not only in macrophages but also in other connective tissue cells, and in epithelium. It was present in spleen (littoral cells and cells within Malpighian bodies), liver (hepatocytes and Kupffer cells), lung (alveolar macrophages and bronchial epithelium), brain (neurones), lymph nodes (histiocytes in germinal centres, sinusoid lining cells) and stomach (parietal and mucous neck cells). Cathepsin D was also found in carcinomas of bronchus, stomach, colon, kidney, breast, ovary, bladder and pancreas, both in neoplastic epithelium and in stromal cells, but was seldom present in connective tissue neoplasms. A group of malignant lymphomas also contained the enzyme within scattered cells. The distribution of cathepsin D seems to be much wider than that of the structurally related aspartic proteinases pepsin, gastricsin, and renin.

Brain↗
PubMed1986

Hemodynamic response to rapidly infused 25% albumin in sheep: blunting the effects with ibuprofen.

We document the hemodynamic deterioration in two patients given very rapid intravenous infusions of 25% albumin. We developed an animal model to further elucidate the mechanism involved. Seven sheep were instrumented for the measurement of cardiac index (CI), pulmonary artery pressure (PAP), mean arterial pressure (MAP), left atrial pressure (LAP) and given 0.5 g/kg of Hyland brand 25% albumin over 5 min. Systemic vascular resistance index (SVRI), pulmonary vascular resistance index and left and right ventricular stroke work index were calculated. Equal volumes of normal saline were given to the same sheep as controls. Albumin significantly (p less than 0.05) increased MAP, PAP, LAP and SVRI, while CI decreased over the 3-10-min interval. Ibuprofen (14 mg/kg) intravenously administered 15 min prior to albumin, blunted all the above responses. This implicates a prostanoid as the possible mediator of these changes.

Animals↗
PubMed1986

Pulmonary deposition sites of an inhaled radiolabeled submicronic aerosol.

The clearance rate of aerosolized and deposited 99mtechnetium diethylenetriamine pentacetate provides an index of lung epithelial permeability. However, the location of the epithelium being assessed is uncertain. We determined the percentage of submicronic aerosol deposited on ciliated and nonciliated airways in healthy and damaged lungs using 99mTc-sulphur (99mTc-S) colloid. Colloidal particles can be cleared by mucociliary transport but not through the epithelium. Piglets aged 12-72 h, weighing 0.7-3.3 kg (average 1.6 kg) were anesthetized and underwent endotracheal intubation. 99mTc-S labeled submicronic aerosol (Syntevent II) was collected in anesthetic bags and either inhaled spontaneously (n = 4), or insufflated by hand (n = 5) at 30 breaths per min and a peak airway pressure of 15 cm H2O. Piglets were immediately extubated and scanned on a gamma camera. Twenty-four h later a repeat scan was performed. The residual radioactivity represents the amount of aerosol deposited on nonciliated airways. In six other piglets pulmonary damage was produced by an intravenous infusion of air microemboli for 2 to 3 h (0.14 to 0.38 ml/min). The maximal decrease in PaO2 while breathing room air ranged from 24-59 mm Hg. During the last 15 min of infusion they were intubated, insufflated by hand with the 99mTc-S aerosol, and scanned as above. The results demonstrate that approximately three-fourths of the submicronic aerosol is deposited distally to ciliated airways in both healthy and damaged newborn piglet lungs. This suggests that the clearance rate of 99mtechnetium diethylenetriamine pentacetate predominantly reflects epithelial permeability of terminal lung units when a submicronic aerosol is used for delivery to the lung.

Aerosols↗
PubMed1986

Cadmium accumulation and protein binding patterns in tissues of the rainbow trout, Salmo gairdneri.

Rainbow trout were exposed to defined levels of cadmium in their aquarium water for differing periods at a variety of near-lethal concentrations that ensured the survival of the majority of the fish. The gills, liver and kidney together accounted for 99% of the accumulated load of body cadmium in the fish under these conditions. Although the proportion of total cadmium present in the liver remained relatively constant throughout, the distribution of the remainder between gill and kidney altered with the time of exposure. The cadmium in all three organs was bound by two low molecular weight proteins distinct in character from metallothionein. The isoforms of metallothionein were also present but were found to bind only zinc and copper. By contrast, when trout were injected with cadmium intraperitoneally, most of the metal accumulated in the liver where it was sequestered by the two isoforms of metallothionein. Pre-exposure of the trout to either a low concentration of cadmium (for several months) or to an elevated concentration of zinc (for 5 days) allowed the animals to survive a subsequent exposure to a high, otherwise lethal concentration of cadmium. The proteins responsible for sequestration of the two metals were identified, but two different mechanisms seemed to be involved in the protection of the animals. The significance of these observations in terms of the induction of proteins and the prevention of the toxic effects of cadmium is considered.

Animals↗
PubMed1986

Elevated plasma vasopressin (AVP) levels during resection of pheochromocytomas.

During the evaluation of epidural blockade with light general anesthesia for pheochromocytoma resection, increases in plasma arginine vasopressin (AVP) concentrations were noted. We measured AVP levels in conjunction with plasma catecholamines during perioperative maneuvers in eight consecutive patients undergoing resection of pheochromocytomas. Hormonal responses (mean +/- SE) for preoperative baseline and peak values during tumor manipulation were as follows: AVP, 5 microgram/ml or picogram/ml (+/- 1.7) to a peak of 129 pg/ml (+/- 44) pg/ml; norepinephrine, 5,834 pg/ml (+/- 2,564) to 72,422 (+/- 31,433) pg/ml; epinephrine, 1,033 pg/ml (+/- 405) to 56,444 (+/- 23,542) pg/ml; and dopamine, 165 pg/ml (+/- 35) to 4,231 (+/- 1,318) pg/ml. Maximal AVP values occurred with tumor manipulation and remained elevated for 24 hours postoperatively. Neither epidural placement, induction of anesthesia, nor epidural narcotics used for postoperative pain control had any effect on AVP or catecholamine levels. These extraordinarily high concentrations of plasma AVP found during tumor manipulation may contribute to hemodynamic lability and fluid problems in patients undergoing surgery for the treatment of pheochromocytoma.

Adolescent↗