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Biomedical subjects

J K Nicholson

Publications and source records attributed to J K Nicholson.

At least 271 records · Page 15Linked to original sources
PubMed1984

Comparison of T and B cell analyses on fresh and aged blood.

We have compared T and B cell analyses using whole blood, separated lymphocytes, and separated, frozen, then thawed lymphocytes to see how long blood can be kept before separation and analysis. We also examined the effect of various anticoagulants and the effect of diluting blood in culture media on T and B cell analysis over time. We found that the whole blood method is a very reliable method for T and B cell analysis, even 4 days after the blood is drawn, provided that heparin or ACD is the anticoagulant used. Separated lymphocytes and cryopreserved lymphocytes from blood that was separated within 24 h of collection was satisfactory; however, results were less consistent if separation was delayed more than 24 h. For lymphocyte separation, blood collected in heparin or ACD held up better over time than did blood collected in EDTA, and dilution with either RPMI 1640 or McCoy's medium gave better lymphocyte separation in older blood.

Antibodies, Monoclonal↗
PubMed1984

Proton-nuclear-magnetic-resonance studies of serum, plasma and urine from fasting normal and diabetic subjects.

Resonances for the ketone bodies 3-D-hydroxybutyrate, acetone and acetoacetate are readily detected in serum, plasma and urine samples from fasting and diabetic subjects by 1H n.m.r. spectroscopy at 400 MHz. Besides the simultaneous observation of metabolites, the major advantage of n.m.r. is that little or no pretreatment of samples is required. N.m.r. determinations of 3-D-hydroxybutyrate, acetoacetate, lactate, valine and alanine were compared with determinations made with conventional assays at six 2-hourly intervals after insulin withdrawal from a diabetic subject. The n.m.r. results closely paralleled those of other assays although, by n.m.r., acetoacetate levels continued to rise rather than reaching a plateau 4h after insulin withdrawal. The 3-D-hydroxybutyrate/acetoacetate ratio in urine during withdrawal gradually increased to the value observed in plasma (3.0 +/- 0.2) as determined by n.m.r. The acetoacetate/acetone ratio in urine (17 +/- 6) was much higher than in plasma (2.5 +/- 0.7). Depletion of a mobile pool of fatty acids in plasma during fasting, as seen by n.m.r., paralleled that seen during insulin withdrawal. These fatty acids were thought to be largely in chylomicrons, acylglycerols and lipoproteins, and were grossly elevated in plasma samples from a non-insulin-dependent diabetic and in cases of known hyperlipidaemia.

3-Hydroxybutyric Acid↗
PubMed1984

Immunologic analysis of intraocular mononuclear cell infiltrates in uveitis.

The pathogenesis of chronic idiopathic uveitis is not known. Analysis of inflammatory site (ie, intraocular) lymphocytes in the aqueous humor and/or vitreous cavity was performed with monoclonal antibodies and a cell sorter. The mononuclear cell population within the aqueous humor of eyes with acute idiopathic uveitis resembled that observed in the peripheral blood. In contrast, eyes with chronic idiopathic uveitis displayed a scarcity of T cells within the vitreous. Eyes with chronic uveitis of presumed infectious cause did not show similar changes. These observations are consistent with the hypothesis that intraocular T-cell immunoregulation of B-cell function may be defective in some stages of chronic idiopathic uveitis.

Aqueous Humor↗
PubMed1984

Comparative distributions of zinc, cadmium and mercury in the tissues of experimental mice.

Different groups of mice were injected with cadmium, zinc and mercury. Zinc injections had no effect on zinc tissue levels while both mercury and cadmium accumulated in various tissues. Cadmium persisted in the tissues much longer than mercury, and while the mercury concentrations began to decline as soon as dosing ceased, cadmium concentrations in kidney and intestine increased even after dosing ceased. There appeared to be an interrelationship between cadmium concentrations in spleen and intestine which warrants some further investigations. There was a linear, but discontinuous, effect of cadmium on zinc concentrations in liver, kidney and pancreas which may depend on metallothionein biochemistry. Mercury injections had no effect on zinc metabolism. It is proposed that differences in the rate of excretion of cadmium and mercury from the kidney could explain the differential accumulation of cadmium and mercury in animals.

Animals↗
PubMed1984

Immunoregulatory subsets of the T helper and T suppressor cell populations in homosexual men with chronic unexplained lymphadenopathy.

Unexplained, generalized lymphadenopathy in homosexual men, which can be a prodrome to the acquired immunodeficiency syndrome, is associated with impaired cell-mediated immunity, a low ratio of T helper-inducer to T suppressor-cytotoxic cells (defined by the T4 and T8 monoclonal antibodies), and hypergammaglobulinemia. We performed double-marker studies on T cells by using a panel of monoclonal antibodies (Ia, T17, TQ1, and Leu-8), which reportedly detect activation or functional subsets of the T4 and T8 T cell populations. The T4:TQ1- or T4:Leu-8- subset, which is the major helper subset for B cell responses, is normally represented in lymphadenopathy patients. A depression in the reciprocal subset, T4:TQ1+ or T4:Leu-8+, accounts for the T4 T cell defect. Similarly, the TQ1 and Leu-8 markers delineate the abnormality of T8 T cells: the T8:TQ1- or T8:Leu-8- subset is elevated, whereas the T8:TQ1+ or T8:Leu-8+ subset is normally represented. We found no evidence of excessive activation of T4 T cells by using the T17 or Ia monoclonal antibodies. We did find an overall increase in Ia-positive T cells; however, this was due to increased T8:Ia+ cells. In functional studies, immunoglobulin production induced by pokeweed was subnormal. Most lymphadenopathy patients had normal T helper cell function when combined with normal B cells. The dampened pokeweed responses could be partially explained by depression of the T4:TQ1+ (or T4:Leu-8+) subset (which has minor help-associated function) and/or greater than expected suppression. However, subnormal pokeweed responses could not be totally explained by immunoregulatory T cell abnormalities because we also found an intrinsic defect in the B cell responses of lymphadenopathy patients.

Acquired Immunodeficiency Syndrome↗
PubMed1984

Urinary excretion of acetaminophen and its metabolites as studied by proton NMR spectroscopy.

Acetaminophen and its glucuronide, sulfate, N-acetyl-L-cysteinyl, and L-cysteinyl metabolites can be rapidly detected by 1H NMR spectroscopy of intact, untreated human urine. Study of the time course of excretion of these metabolites in five clinically normal men after ingestion of the usual 1-g therapeutic dose of the drug showed that the mean 24-h excretion of the drug and these metabolites as determined by NMR was 77.3% of the dose. Respective relative proportions of the above metabolites were 49.9%, 37.6%, 3.0%, and 9.5% (L-cysteinyl plus free drug). Excretion of some other metabolites in urine, including creatinine, citrate, hippurate, and sarcosine was measured concurrently. Excretion of creatinine and sarcosine was closely correlated.

Acetaminophen↗
PubMed1984

Use of high-resolution proton nuclear magnetic resonance spectroscopy for rapid multi-component analysis of urine.

Numerous low-Mr metabolites--including creatinine, citrate, hippurate, glucose, ketone bodies, and various amino acids--have been identified in 400- and 500-MHz proton nuclear magnetic resonance (1H NMR) spectra of intact human urine. The presence of many of these was related to the specific condition of the donors: humans in different physiological states (resting, fasting, or post-exercise) and pathological conditions (e.g., diabetes mellitus, cadmium-induced renal dysfunction). We have also monitored the metabolism of simple nonendogenous compounds (methanol and ethanol) and of acetaminophen. The pH-dependencies of the NMR chemical shifts of some urine components are reported. Our studies show that high-resolution 1H NMR spectroscopy provides a fast, simple method for "fingerprint" identification of urinary compounds. In some cases, analytes can be quantified by standard additions or by comparing integrated peak areas for the metabolites with those for creatinine. Determinations of creatinine by 1H NMR spectroscopy compared well with those by an independent chemical assay based on the Jaffé reaction.

Acetaminophen↗
PubMed1983

Inhibition of adenosine deaminase leads to enhanced antibody responses in the mouse.

Inhibition of adenosine deaminase activity leads to decreased cellular immunity. The effect of deoxycoformycin (DCF), a potent inhibitor of adenosine deaminase, on the ability of mouse spleen cells to generate antibody responses in vitro has been examined. With either continuous exposure to or pretreatment of the cells with deoxycoformycin, there was a decrease in cell survival and an increase in antibody-producing cells in the surviving cell population. To identify the cell population most susceptible to the inhibitor, the spleen was separated into B-cell, and T-cell, and macrophage components and each population was pretreated with deoxycoformycin before combination with its complementary treated or untreated population. Deoxycoformycin pretreatment had no effect on macrophages or B cells; however, pretreatment of the T cells resulted in increased antibody responses. When T cells and B cells were both pretreated and combined, there was a synergistic increase in the antibody response. In addition, supernatants from cultures in which both B cells and T cells had been pretreated with DCF were capable of enhancing antibody responses in cultures containing DCF-treated T cells. Though adenosine was increased in the stimulatory culture supernatants, adenosine alone did not enhance antibody responses in either untreated or DCF-treated cultures.

Adenosine Deaminase Inhibitors↗
PubMed1983

High resolution 1H n.m.r. studies of vertebrate blood and plasma.

Spin echo Fourier transform proton n.m.r. spectra of whole blood contain resonances from both erythrocytes and plasma. A large number of well-resolved signals from mobile protons of low-molecular-weight metabolites in plasma and serum have been identified. Spectra from the plasmas of eight animal species and commercial, quality control sera are compared. CaEDTA2- and MgEDTA2- resonances can be used for the simultaneous determination of EDTA-chelatable calcium and magnesium concentrations in intact plasma and other biological fluids. Cholesterol is too immobile to contribute to the spectra of intact plasma, but is readily estimated by n.m.r. in both its free and esterified forms after extraction into methanol.

Animals↗
PubMed1983

88MHz 113Cd-n.m.r. studies of native rat liver metallothioneins.

Well-resolved 113Cd-n.m.r. spectra of 113Cd-induced rat liver metallothioneins 1 and 2 are obtainable even at 88 MHz (9.4T). The line-widths of resonances are not dominated by chemical-shift-anisotropy relaxation. The increased spectral dispersion will significantly aid the study of the native (Cd- and Zn-containing) metallothioneins.

Animals↗
PubMed1983

X-ray microanalysis of proximal and distal tubule cells in the mouse kidney, and the influence of cadmium on the concentration of natural intracellular elements.

Quantitative X-ray microanalysis of frozen freeze-dried sections of mouse cortex have been used to determine the concentrations of Na, Mg, P, S, Cl, K, Ca and Cd in normal mice and those subjected t 0.7 mumol of cadmium chloride in two subcutaneous injections. These injections result in tissue levels of approximately 100 mg Cd/kg dry weight (less than 1 mM) in whole kidney when analysed by atomic absorption spectrometry. There were distinct and characteristic differences -- 'fingerprints' -- in the elemental composition of both cytoplasm and mitochondria in proximal and distal tubules of normal mice that were distributed by the cadmium treatment. The most significant effect of the cadmium injections was a highly significant increase in the sulphur content of the cytoplasm and mitochondria of distal tubules and a loss in concentration of Mg, P, Cl, K, and particularly Na, from the mitochondria. These results are discussed in the light of current concepts of metallothionein induction (metallothionein is a sulphur-rich protein that acts to bind, amongst other metals, cadmium) and the lack of damage observed in the distal tubules.

Animals↗
PubMed1983

The fine structure of dark or intercalated cells from the distal and collecting tubules of avian kidneys.

Dark or intercalated cells were identified in the terminal portion of the distal tubules and in the intralobular collecting tubules of four species of birds. The morphological features of these cells varied only slightly from species to species and were very similar to cells found in topographically analogous regions of mammalian nephrons. Characteristic vesicles usually filled the apical region of the dark cells and were often in direct continuity with the apical plasma membrane which was frequently thrown into elaborate folds, microvilli and microplicae. Observations suggested that the cells might be involved in some form of cyclical secretory activity. The similarity in structure between avian and mammalian dark cells suggested that they might perform similar functions and that the study of avian cells might aid the elucidation of the mammalian cell function. The possible functions of the avian cells were discussed in relation to physiological studies in mammalian kidneys and it was suggested that they might be involved with proton and potassium pumping and control of urinary buffer concentrations.

Animals↗
PubMed1983

The histology and fine structure of the ureter of the European starling (Sturnus vulgaris).

Light and electron microscopic techniques were employed to study the structure of the ureter of the starling (Sturnus vulgaris). Particular attention was paid to the characterisation of the epithelial cell types. Differences were found in the chemical composition of the mucins found in the ureteric epithelial cells and the medullary collecting ducts, which suggested that they might perform different functions. The epithelial cells were of two main types. The basally situated cells were electron-lucent, apparently relatively undifferentiated, and contained little rough endoplasmic reticulum or mucigen. The cells which were directly adjacent to the lumen were highly specialised for mucus secretion and contained extensive rough endoplasmic reticulum and large numbers of mucigen-containing vacuoles. Cells of intermediate character were also observed and the relationships between the epithelial cell types were discussed. The possibility of a holocrine mode of mucus secretion in the avian ureteric epithelium was discussed.

Animals↗
PubMed1982

The microanatomy of the distal tubules, collecting tubules and collecting ducts of the starling kidney.

Light and electron microscopic techniques were employed to characterise the various cell types found in the distal tubules, collecting tubules and collecting ducts in the kidneys of wild starlings (Sturnus vulgaris). There was a gradual change in cell characteristics along the length of the distal tubule. A short transition zone was identified, between the distal tubule and the intralobular collecting tubule, which contained cell types that were characteristic of both segments. The end of the distal tubule was marked by the appearance of scattered dark cells and occasional mucin-secreting cells. The dark cells were electron-dense and usually possessed many microvesicles in the subapical region; there were also numerous, stubby apical microprocesses in many cases. In the basal regions of these cells were many, short, regular infoldings of the plasma membrane. The initial part of the intralobular collecting tubule was lined by approximately equal numbers of dark and mucin-secreting cells. However, as the tubule progressed towards the lobular periphery, the number of dark cells declined. Few dark cells were observed in the perilobular collecting ducts and none in the medullary ducts which were lined by columnar mucin-secreting cells. The mucin-secreting cells possessed a prominent supranuclear Golgi apparatus and apical vacuoles containing a strongly PAS- and alcian blue-positive mucigen. Critical electrolyte concentration methods, using alcian blue in the presence of magnesium chloride, indicated that the mucigen contained large amounts of a strongly sulphated component, but was probably of a mixed nature. The dark cells were slightly PAS-positive but only very weakly alcian blue-positive at the cell apices. The roles of the various cell types were discussed in relation to the uric acid excretion habit of birds.

Animals↗
PubMedDate not supplied

Development of a model for classification of toxin-induced lesions using 1H NMR spectroscopy of urine combined with pattern recognition.

Pattern recognition approaches were developed and applied to the classification of 600 MHz 1H NMR spectra of urine from rats dosed with compounds that induced organ-specific damage in either the liver or kidney. Male rats were separated into groups (n = 5) and each treated with one of the following compounds; adriamycin, allyl alcohol, 2-bromoethanamine hydrobromide, hexachlorobutadiene, hydrazine, lead acetate, mercury II chloride, puromycin aminonucleoside, sodium chromate, thioacetamide, 1,1,2-trichloro-3,3,3-trifluoro-1-propene or dose vehicle. Urine samples were collected over a 7 day time-course and analysed using 600 MHz 1H NMR spectroscopy. Each NMR spectrum was data-reduced to provide 256 intensity-related descriptors of the spectra. Data corresponding to the periods 8-24 h, 24-32 h and 32-56 h post-dose were first analysed using principal components analysis (PCA). In addition, samples obtained 120-144 h following the administration of adriamycin and puromycin were included in the analysis in order to compensate for the late onset of glomerular toxicity. Having established that toxin-related clustering behaviour could be detected in the first three principal components (PCs), three-quarters of the data were used to construct a soft independent modelling of class analogy (SIMCA) model. The remainder of the data were used as a test set of the model. Only three out of 61 samples in the test set were misclassified. Finally as a further test of the model, data from the 1H NMR spectra of urine from rats that had been treated with uranyl nitrate were used. Successful prediction of the toxicity type of the compound was achieved based on NMR urinalysis data confirming the robust nature of the derived model.

Animals↗