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Biomedical subjects

P Jackson

Publications and source records attributed to P Jackson.

At least 235 records · Page 13Linked to original sources
PubMed1983

Two temperature-sensitive mutants of Saccharomyces cerevisiae with altered expression of mating-type functions.

Two mutants of Saccharomyces cerevisiae have been isolated from normal haploid MAT alpha strains and characterized as having temperature-sensitive, pleiotropic phenotypes for functions associated with mating. At the permissive temperature, 23 degrees C, they were found to behave as normal MAT alpha haploids with respect to mating efficiency, sporulation in diploids formed with MAT a strains, secretion of alpha-factor, and failure to secrete the MATa-specific products, a-factor and Barrier. At higher temperatures they were found to decline in mating and sporulation efficiency and to express the a-specific functions. Genetic analysis established that one of these mutants, PE34, carries a temperature-sensitive allele of the MAT alpha 2 gene and that the other, PD7, carries a temperature-sensitive allele of the TUP1 gene.

Alleles↗
PubMed1983

Isolation of PGP 9.5, a new human neurone-specific protein detected by high-resolution two-dimensional electrophoresis.

Protein gene product (PGP) 9.5 is a new brain-specific protein originally detected by high-resolution two-dimensional electrophoresis of the soluble proteins of human brain and other organs. We have purified this protein from human brain and raised a rabbit antihuman PGP 9.5 antiserum. The protein has a monomer molecular weight of approximately 27,000 and is present in brain at concentrations at least 50 times greater than in other organs. Immunoperoxidase labelling has localised PGP 9.5 to neurones in the human cerebral cortex with no evidence of staining of glial elements. PGP 9.5 is estimated to be present in brain at concentrations of 200-500 micrograms/g wet weight and represents a major protein component of neuronal cytoplasm. This new neurone-specific cytoplasmic marker may prove useful in studies of neuronal development and in the detection of neuronal damage in disease of the nervous system.

Brain Chemistry↗
PubMed1983

Surface membrane staining of immunoglobulins in paraffin sections of non-Hodgkin's lymphomas using immunogold-silver staining technique.

The immunogold-silver staining (IGSS) method is a new immunostaining technique with much enhanced sensitivity for demonstration of antigens in paraffin sections. A series of 10 non-Hodgkin's lymphomas of B cell type were stained for surface membrane immunoglobulins by the IGSS and peroxidase-antiperoxidase (PAP) methods using paraffin sections and polyclonal primary antisera. The resulting staining patterns were compared with those obtained using frozen sections of the same tissues, monoclonal antibodies and the immunoperoxidase technique. The IGSS method gave a clear demonstration of surface membrane immunoglobulins in neoplastic lymphocytes using paraffin sections and the pattern of staining achieved was comparable to that obtained by the immunoperoxidase technique employing frozen sections and monoclonal antibodies. PAP staining of paraffin sections consistently failed to demonstrate the presence of any surface membrane immunoglobulin. The IGSS method provides a new approach to the diagnosis of B cell lymphomas in which routinely fixed and processed tissues may be employed to demonstrate monoclonality.

Adult↗
PubMed1983

Immunogold-silver staining: new method of immunostaining with enhanced sensitivity.

A new method for demonstrating antigens in paraffin sections of formol sublimate-fixed tissue is described that utilizes an "indirect" immunohistological technique employing immunoglobulin adsorbed to colloidal gold as the secondary antiserum. The gold particles introduced to antigenic sites are revealed by a silver precipitation reaction. This technique, the immunogold-silver staining method, is of much enhanced sensitivity (up to 200-fold) as compared with standard immunoperoxidase and immunogold staining methods. The results have been confirmed in a study of immunoglobulins in reactive human tonsil. The use of this new method for double immunolabeling is also described.

Animals↗
PubMed1982

The relation between the membrane cholesterol content and anion exchange in the erythrocytes of patients with cholestasis.

The anion transport system was assessed in erythrocytes from fifteen patients with cholestasis and fifteen healthy subjects as the exchange of intracellular chloride for extracellular pyruvate. The rate constant of pyruvate-chloride exchange was significantly reduced in the patients compared with the controls. The membranes of the erythrocytes of the patients compared with the controls contained more cholesterol and phospholipid and had a higher molar ratio of cholesterol to phospholipid. The rate constant of pyruvate-chloride exchange was directly related to the cholesterol to phospholipid ratio of the membranes in the patients. In vitro loading with cholesterol of erythrocytes from healthy subjects reduced the rate constant of pyruvate-chloride exchange by an amount which was related to the increase in the cholesterol to phospholipid ratio of the cell membrane. The inhibitory effect of cholesterol loading on anion transport was similar to its previously reported inhibitory effect on the furosemide-sensitive sodium transport system in the erythrocytes.

Anions↗
PubMed1982

Role of antenatal radiography in the management of breech deliveries.

a retrospective study was made of 228 mature singleton breech deliveries occurring over a 2 year period to determine the role of antenatal radiography, in particular, of pelvimetry. Many (65%) had abdominal radiography. Where antenatal pelvimetry was performed (38%) the infants were in significantly better condition during the neonatal period; this was most marked with parous women. There was no significant difference in the neonatal condition of 25 infants born vaginally of women with favourable pelvimetry compared with 31 infants born by elective caesarean sections.

Adult↗
PubMed1982

Purification, properties, and immunohistochemical localisation of human brain 14-3-3 protein.

A protein has been purified from human brain that appears to be the human equivalent of bovine 14-3-3 protein. On polyacrylamide gel electrophoresis the protein migrates as a faster major component, termed 14-3-3-2 protein, and a slower minor component, termed 14-3-3-1 protein, which consists of approximately 12% of the total protein. Both 14-3-3-1 and 14-3-3-2 have a native molecular weight of approximately 67,000. 14-3-3-2 appears to have the subunit composition alpha beta; 14-3-3-1 has the composition beta'beta'. Peptide mapping with Staphylococcus aureus V8 proteinase shows that alpha and beta subunits are unrelated but the beta and beta' subunits show some common peptides. Immunoperoxidase labelling shows that 14-3-3 is localised in neurones in the human cerebral cortex. 14-3-3 shows no enolase, creatine kinase, triose phosphate isomerase, ATPase, cyclic nucleotide-dependent protein kinase, or purine nucleoside phosphorylase activity. 14-3-3 does not bind calcium and does not appear to be related to calmodulin, calcineurin, tubulin, neurofilament proteins, clathrin-associated proteins, or tropomyosin. The functional significance of this neuronal protein remains obscure.

14-3-3 Proteins↗
PubMed1982

Human 14-3-3 protein: radioimmunoassay, tissue distribution, and cerebrospinal fluid levels in patients with neurological disorders.

An antiserum to human 14-3-3 protein has been produced in rabbits. The protein was a poor antigen and attempts to improve immunogenicity were unsuccessful. A radioimmunoassay was developed using the antiserum, 125I-14-3-3-2, and unlabelled 14-3-3-2 as standards. The assay had a sensitivity limit of 2.5 ng.ml-1. The minor component of human 14-3-3 protein (14-3-3-1 protein) cross-reacted to approximately 10% in the assay. Human tissues were surveyed for 14-3- protein by two-dimensional electrophoresis and by radioimmunoassay. Two-dimensional electrophoresis showed a 14-3-3 protein complex in brain, intestine, and testis, but not in other tissues. Radioimmunoassay showed that although brain had the highest concentration of 14-3-3 (13.3 microgram.mg-1 soluble protein), immunoreactivity was present in all tissues, with the concentration in intestine and testis approaching 50% of the brain level. Lower levels (less than 1.0 microgram.mg-1 soluble protein) were seen in liver, kidney, skeletal muscle, and erythrocytes. The immunoreactivity present in tissues other than brain showed the same molecular weight and charge characteristics and authentic 14-3-3 protein. The radioimmunoassay also detected 14-3-3 protein in serum (50 ng.ml-1) and in CSF (5-130 ng.ml). The immunoreactivity present in CSF appeared to be intact 14-3-3 protein. CSF 14-3-3 levels were measured in 82 patients with various neurological disorders. Measurements of this protein did not appear sufficiently discriminating to be of diagnostic value.

14-3-3 Proteins↗
PubMed1982

Demonstration of basic human-brain-specific proteins by the BASO-DALT system.

We used the BASODALT system (Cell 12: 1133--1142, 1977) of high-resolution two-dimensional gel electrophoresis to resolve proteins in extracts of human brain and, for comparison, those in nine other human organs. At least 180 protein-staining spots are visible on a BASODALT electrophoretogram of water-soluble human brain proteins. By electrophoresing extracts of different human organs, separately and mixed with brain extract, we could detect 14 basic spots that appear to be present in brain in concentrations at least 20-fold those in any other organ. Measurement of these new basic brain-predominant proteins may provide useful diagnostic information in neurological disorders.

Adrenal Glands↗
PubMed1981

Isolation and characterization of calmodulin from an insulin-secreting tumour.

A major protein constituent of a rat islet cell tumour that exhibited Ca2+-dependent changes in electrophoretic mobility has been purified to homogeneity and compared in its physicochemical and biological properties with bovine brain and rat brain calmodulin (synonymous with phosphodiesterase activator protein, calcium-dependent regulator, troponin C-like protein and modulator protein). The protein, like these calmodulins, contained trimethyl-lysine, exhibited a blocked N-terminus and had an identical amino-acid composition and molecular weight on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. Peptide "maps' prepared after digestion of the three proteins with trypsin, papain or Staphylococcus V-8 proteinase were virtually superimposable. Ca2+ altered the electrophoretic mobilities the enhanced the native protein fluorescence in an equivalent manner with all three proteins. Equilibrium dialysis experiments demonstrated in each case the binding of 4g-atoms of calcium/mol of protein; the binding sites were equivalent and showed Kd 0.8 microM. Tumour and brain proteins were equipotent as Ca2+-dependent activators of partially purified rat brain cyclic nucleotide phosphodiesterase, and in this action were inhibited in an identical manner by trifluoperazine. The proteins also exhibited the common property of Ca2+-dependent binding to troponin I, histone H2B and myelin basic protein. The estimated tumour content of calmodulin was 450 mg/kg fresh wt., a value similar to that reported in islets of Langerhans. These results further document the validity of the islet cell tumour as an experimental model of Ca2+-mediated molecular events associated with insulin secretion. They also suggest that brain calmodulin may be substituted for endogenous calmodulin in experimental investigations into the mechanism of insulin secretion.

Adenoma, Islet Cell↗
PubMed1981

The demonstration of new human brain-specific proteins by high-resolution two-dimensional polyacrylamide gel electrophoresis.

High-resolution multiple two-dimensional polyacrylamide gel electrophoresis (ISODALT) has been used to analyse soluble protein extracts from human brain and 12 other human organs. Approximately 200 protein gene products can be visualised on an electrophoretogram of soluble human brain proteins. By electrophoresing extracts of different human organs separately and mixed with brain extract, 8 proteins have been found which appear to be present in brain in concentrations at least 20 times greater than in any other organ. Four of these brain-specific proteins have been identified by co-electrophoresis with purified proteins as 14-3-2 protein, creatine kinase-BB isoenzyme, aldolase C4 isoenzyme, and 14-3-3 protein. The identities of the remaining 4 proteins are unknown.

Brain↗
PubMed1980

The isolation and characterisation of guinea-pig polymorphonuclear leucocyte actin and myosin.

The contractile proteins actin and myosin have been isolated from the soluble phase of guinea-pig polymorphonuclear leucocytes and partially characterised. Two forms of actin have been identified, designated 'Mg-actin' and 'KCl-actin'. They have different polymerising properties but their propensity to form synthetic homologous and heterologous actomyosins and to inhibit DNAase-1 does not significantly differ. Both show beta and gamma isoelectric forms in focusing gels and the Mg-actin accounts for about 5% of the soluble-phase protein and te KCl-actin around 2%. Leucocyte myosin has been isolated by affinity chromatography on N6-ADP-Sepharose with a good enrichment of both Ca2+-ATPase and the ATPase activity measured in the absence of Ca2+ or Mg2+ and in the presence of EDTA. This protein, too, has the capacity to form synthetic homologous and hybrid actomyosins with enhancement of the basal Mg2+-ATPase activity. The ratio of actin to myosin in the leucocyte calculated on a molar basis is well in excess of 100, a figure consistent with the findings from other non-muscle cells.

Actins↗
PubMed1980

The prophylactic use of metronidazole in caesarean section.

A double-blind study of 73 patients was undertaken to evaluate the prophylactic effect of short-term metronidazole in caesarean section. Metronidazole, 500 mg, given intravenously prior to making the incision, followed by 2 g, rectally, on completion of surgery failed to reduce the incidence of infection post-operatively. There was no reduction in the number of patients requiring antibiotics or in the quantity of post-operative pyrexia, as assessed by the fever index. The incidence of post-operative pyrexia was not affected by the duration of ruptured membranes or the use of a fetal scalp electrode.

Bacterial Infections↗
PubMed1980

Female sterilisation: a five-year follow-up in Auckland.

During the year 1972/73 sterilisation by tubal occlusion was performed at National Women's Hospital on 831 women with a mean age of 32.5 years and a mean parity of 4.6. Two were unknowingly pregnant at the time of operation and eight became pregnant within five years mainly because or recanalization of the tube. Eighty-one percent had no regrets about being sterilised but eleven women experienced a major degree of regret. Eight patients had sought reversal of their sterilisation. Following the operation libido was decreased in 10% of Europeans and 45% of Maoris. Menorrhagia was a common complaint after sterilisation and 7.5% had a hysterectomy within five years.

Adult↗