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K Ferguson

Publications and source records attributed to K Ferguson.

18 recordsLinked to original sources
PubMed1991

Genetic and biochemical analysis of the adenylyl cyclase of Schizosaccharomyces pombe.

The adenylyl cyclase gene, cyr1, of Schizosaccharomyces pombe has been cloned. We have begun an analysis of the function and regulation of adenylyl cyclase by disrupting this gene and by over-expressing all or parts of this gene in various strains. cyr1- strains are viable and contain no measurable cyclic AMP. They conjugate and sporulate under conditions that normally inhibit wild-type strains. Strains containing the cyr1 coding sequences transcribed from the strong adh1 promoter contain greatly elevated adenylyl cyclase activity, as measured in vitro, but only modestly elevated cAMP levels. Such strains conjugate and sporulate less frequently than wild-type cells upon nutrient limitation. Strains which carry the wild-type cyr1 gene but that also express high levels of the amino terminal domain of adenylyl cyclase behave much like cyr1-strains, suggesting that the amino terminal domain can bind a positive regulator. A protein that copurifies with the adenylyl cyclase of S. pombe cross-reacts to antiserum raised against the S. cerevisiae adenylyl cyclase-associated regulatory protein, CAP.

Adenylyl Cyclases↗
PubMed1991

CAP is a bifunctional component of the Saccharomyces cerevisiae adenylyl cyclase complex.

CAP, a protein from Saccharomyces cerevisiae that copurifies with adenylyl cyclase, appears to be required for yeast cells to be fully responsive to RAS proteins. CAP also appears to be required for normal cell morphology and responsiveness to nutrient deprivation and excess. We describe here a molecular and phenotypic analysis of the CAP protein. The N-terminal domain is necessary and sufficient for cellular response to activated RAS protein, while the C-terminal domain is necessary and sufficient for normal cellular morphology and responses to nutrient extremes. Thus, CAP is a novel example of a bifunctional component involved in the regulation of diverse signal transduction pathways.

Adenylyl Cyclases↗
PubMed1991

Effects of chronic alpha-adrenergic receptor blockade on peripheral nerve conduction, hypoxic resistance, polyols, Na(+)-K(+)-ATPase activity, and vascular supply in STZ-D rats.

The effects of alpha-receptor blockade on nerve conduction, hypoxic resistance, ouabain-sensitive Na(+)-K(+)-ATPase, nerve polyols, and capillary density were examined in streptozocin-induced diabetic (STZ-D) rats. Nondiabetic and untreated diabetic control groups were used. Diabetes duration was 2 mo. There were two treated diabetic groups. A "prevention" group received 5 mg/kg prazosin for 2 mo from the induction of diabetes. A "reversal" group was untreated for the 1st mo and was given prazosin for the subsequent month. Conduction was measured in motor nerves supplying tibialis anterior and gastrocnemius muscles and sensory saphenous nerve. Diabetes resulted in 15-29% reductions in conduction velocity (P less than 0.01). In the prevention group, conduction deficits were minimal compared with untreated diabetes (P less than 0.01). In the reversal group, motor conduction was also substantially improved, although sensory conduction was not significantly affected. In vitro measurement of sciatic nerve hypoxic resistance revealed a 49% increase in the time taken for compound action potential amplitude to reach half its initial value with diabetes (P less than 0.01). This was largely prevented by prazosin treatment (P less than 0.01), although treatment had a lesser effect in the reversal group. Treatment had no effect on nerve polyol levels or Na(+)-K(+)-ATPase activity. Functional improvements with prazosin were probably based on increased vasa nervorum perfusion. There was a 20% elevation of endoneurial capillary density (P less than 0.01) in both prevention and reversal groups. We conclude that vascular factors play an important role in the etiology of experimental diabetic neuropathy, and functional changes may be corrected by chronic vasodilator treatment.

Action Potentials↗
PubMed1990

Cloning and characterization of CAP, the S. cerevisiae gene encoding the 70 kd adenylyl cyclase-associated protein.

Adenylyl cyclase from S. cerevisiae contains at least two subunits, a 200 kd catalytic subunit and a subunit with an apparent molecular size of 70 kd, which we now call CAP (cyclase-associated protein). We cloned a cDNA encoding CAP by screening a yeast cDNA expression library in E. coli with antisera raised against the purified protein. The cDNA contained an open reading frame capable of encoding a 526 amino acid protein that is not homologous to any sequences in the current data bases. Adenylyl cyclase activity in membranes from cells that lacked CAP was not stimulated by RAS2 proteins in vitro. These results suggest that CAP is required for at least some aspects of the RAS-responsive signaling system. Mutants lacking CAP had four additional phenotypes that appear to be unrelated to effects of the RAS/adenylyl cyclase pathway: the inability to grow on rich medium (YPD), temperature sensitivity on minimal medium, sensitivity to nitrogen starvation, and a swollen cell morphology.

Adenylyl Cyclases↗
PubMed1990

Complexing of tissue plasminogen activator with PAI-1, alpha 2-macroglobulin, and C1-inhibitor: studies in patients with defibrination and a fibrinolytic state after electroshock or complicated labor.

Release of tissue plasminogen activator (t-PA) and its interaction with plasma protease inhibitors were studied in two patients with massive defibrination, one after electroshock and soft tissue injury and the other after complicated labor; both had very severe hemorrhage. Large quantities of free t-PA were present in the circulation for several hours. Complexes of t-PA with plasminogen activator inhibitor 1 (PAI-1), alpha 2-macroglobulin and C1-inhibitor were also observed. PAI-1 antigen rose dramatically in both patients, and complexes of t-PA with PAI-1 rose rapidly during the period of observation. In contrast, the complexes of t-PA with alpha 2-macroglobulin and C1-inhibitor, present initially, persisted for short periods only and disappeared when free t-PA disappeared from the circulation. Plasmin was generated initially, as indicated by the presence of plasmin-alpha 2-antiplasmin complexes. Plasma concentrations of alpha 2-macroglobulin, C1-inhibitor, antithrombin III, and alpha 2-antiplasmin were severely depleted initially, but rapidly returned to normal. The observations demonstrate that there is a major release of t-PA in such defibrinating patients, that there is a role for protease inhibitors other than PAI-1 in the regulation of endogenous t-PA, and indicate the great rapidity with which such free t-PA is complexed and cleared.

Adult↗
PubMed1989

Genetic analysis of mammalian GAP expressed in yeast.

We have designed a vector to express the mammalian GAP protein in the yeast S. cerevisiae. When expressed in yeast, GAP inhibits the function of the human H-rasgly12 protein, but not that of the H-rasval12 protein, and complements the loss of IRA1. IRA1 is a yeast gene that encodes a protein with homology to GAP and acts upstream of RAS. Mammalian GAP can therefore function in yeast and interact with yeast RAS. Because expression of GAP complements ira1-mutants, we propose that GAP shares some biochemical functions with IRA1. Other studies indicate that IRA1 controls the level of RAS activity, presumably by regulating GTP hydrolysis. By analogy, we propose that GAP may play a similar role.

Cloning, Molecular↗
PubMed1989

Synergy between 5,10-dideaza-5,6,7,8-tetrahydrofolic acid and methotrexate in mice bearing L1210 tumors.

In vivo studies with 5,10-dideaza-5,6,7,8-tetrahydrofolic acid (DDATHF), an inhibitor of glycinamide ribonucleotide transformylase, indicate that at doses ranging from 2.5 to 10 mg/kg, it prolongs the survival of mice implanted with L1210 tumors. Lower doses of this agent have no effect. Parallel studies with methotrexate indicate that DDATHF is not as potent or as efficacious as methotrexate in this animal model. Low doses of DDATHF combined with low doses of methotrexate can cause a significant increase in the survival of L1210 tumor-bearing mice, suggesting synergism between these two antifolates.

Animals↗
PubMed1989

Anaesthetic agents and their effect on tissue protein synthesis in the rat.

1. Rates of protein synthesis were measured, in vivo, in lung, liver, heart and skeletal muscle of young male rats. Groups of rats were exposed for 1 h duration to one of the following anaesthetic regimens: 1.4% halothane, 2.2% halothane, 1.4% halothane in 66% nitrous oxide, intravenous pentobarbitone (20 mg/kg) and intravenous midazolam (18 mg/kg) combined with fentanyl (2 micrograms/kg). Fractional rates of protein synthesis were determined by injecting [3H]phenylalanine (150 mumol/100 g body weight). 2. Liver protein synthesis was depressed significantly by all regimens, except midazolam/fentanyl, by up to 37.7% of control values. Lung protein synthesis was significantly reduced by all the anaesthetic agents by up to 30% of control rates. 3. The effects of the anaesthetic agents on skeletal muscle and heart were small and not statistically significant. 4. There was no evidence of ventilatory depression as manifested by changes in arterial blood gas partial pressures of CO2 and O2, except in the group treated with 2.2% halothane.

Anesthetics↗
PubMed1989

The production and characterisation of monoclonal antibodies against human prolactin and the development of a two-site immunoradiometric assay.

Monoclonal antibodies against human prolactin (PRL) have been produced and characterised and used to develop a sensitive two-site immunoradiometric assay (IRMA). Nine anti-PRL monoclonal antibodies were assessed for reactivity in immunoblotting experiments with PRL, hPL, hGH and pituitary gland extract. There was no detectable crossreactivity with hPL or hGH. In liquid phase radioimmunoassay (RIA) studies using three of the antibodies there was no detectable crossreaction from hPL or hGH. Five antibodies were positive in immunocytochemical studies using sections of human pituitary gland. Using FPLC purified monoclonal antibodies, a two-site IRMA was developed that could assay PRL over the range 17.5-3500 mIU per litre and was readily adapted to assaying serum samples from patients. The two-site IRMA could be performed within one day without loss of sensitivity and has potential as a rapid and simple method for screening clinical samples.

Antibodies, Monoclonal↗
PubMedDate not supplied

Donor room personnel attitudes toward autologous donors.

Patients with serious illnesses who donate their blood for autologous use create anxiety for many phlebotomists. Donor room staff were surveyed at three donor centers, using confidential questionnaires, to identify their concerns and to evaluate factors associated with reduced anxiety toward autologous donors. Among respondents (n = 93), 58 percent had patient care experience within the last 5 years, which correlated with diminished concern about phlebotomizing cardiac patients (r = .21; p = 0.04). Fifty-seven percent of respondents had drawn blood from greater than 50 autologous donors. Surprisingly, the experience of drawing blood from relatively large numbers of autologous donors did not correlate with increased confidence in phlebotomizing pediatric, cardiac, and elderly patients (r = -.04; p = 0.75). Those respondents who felt that they had adequate medical support agreed with more liberal donor criteria and were more confident about phlebotomizing pediatric, cardiac, and elderly patients (r = -.32; p = 0.001). Those respondents who believed most strongly in the benefits of autologous transfusion had the least anxiety toward donors who were medically more complex (r = .39; p = 0.0001). It is concluded that, contrary to what might be expected, phlebotomizing large numbers of autologous donors does not reduce the anxiety of staff members when they encounter donors with complex medical problems. Factors that do reduce anxiety include dependable physician and other medical support services, previous experience in direct patient care, and knowledge of the benefits of autologous transfusion.

Attitude of Health Personnel↗
PubMedDate not supplied

Initiation of a quality assurance program for social work practice in a teaching hospital.

This first-stage paper describes the steps taken in implementing a quality assurance program. The rationale for writing social work protocols based on medical diagnosis or tasks rather than on psychosocial diagnosis is explained in detail. Protocols for adult rheumatoid arthritis, pediatric cancer, adult discharge planning, and adult nursing home placement are included to demonstrate the result of the medical diagnosis/task approach.

Adult↗
PubMedDate not supplied

Tobacco-related attitudes and counseling practices of Iowa dentists.

Evidence suggests that dentists' efforts to encourage their patients to stop tobacco use can significantly decrease tobacco-related morbidity and mortality. This study identified attitudes and counseling practices of 1116 Iowa dentists and compared results of a subgroup (N = 55) surveyed in both 1983 and 1989 to note changes in their tobacco-related attitudes and practices. Although only 9% of the dentists from the statewide survey felt counseling their patients on tobacco use was inappropriate, 56% reported they did not routinely ask their new patients about tobacco use. With some frequency 90% of the dentists discussed negative health effects of tobacco, whereas only 64% advised their smokers to quit. In addition, fewer than half made special efforts with pregnant patients or those at high risk for heart disease. The vast majority reported seldom if ever using intervention tools such as pamphlets or referral to cessation programs. Data from the subgroup surveyed in 1983 and 1989 indicated few substantial changes in attitudes and counseling practices. Substantial discrepancies exist between dentists' attitudes and counseling practices. Well-designed programs are needed to help dentists select and implement appropriate interventions.

Attitude to Health↗