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Biomedical subjects

C Harvey

Publications and source records attributed to C Harvey.

At least 19 recordsLinked to original sources
PubMed1992

New estimates of the direct costs of traumatic spinal cord injuries: results of a nationwide survey.

New estimates of the direct costs of traumatic spinal cord injuries (SCI) are obtained from a comprehensive survey of the US SCI population. These direct costs, defined as the value (in 1988 dollars) of resources used specifically to treat or to adapt to the SCI condition, represent the average experience of the US SCI population. Responses to a detailed questionnaire administered to a sample of traumatic SCI persons in the United States provide the primary source of data for this study. Analysis of this survey data indicates that more recently injured SCI persons (ie those injured since 1970) spent an average of 171 days in a hospital over the first 2 years post injury. Initial hospital expenses will average $95,203. Home modification costs in excess of $8,000 can also be expected. After recovery and rehabilitation, a SCI person will pay, on average, $2,958 per year in hospital expenses and $4,908 per year for other medical services, supplies and adaptive equipment. Personal assistance costs and costs of institutional care will average $6,269 per year. These cost estimates represent the incremental costs of SCI, ie they exclude any costs that would have been incurred in the absence of SCI.

Adolescent↗
PubMed1992

Potassium channel activators cromakalim and celikalim (WAY-120,491) fail to decrease myocardial infarct size in the anesthetized canine.

The cardioprotective effects of the K channel activator drugs celikalim (WAY-120,491) and cromakalim were studied in a canine model of myocardial infarction consisting of 90 min of ischemia and 5 h of reperfusion. Intracoronary infusion of cromakalim and celikalim at 0.2 microgram/kg/min beginning 10 min before occlusion of the left circumflex coronary artery and continuing throughout the duration of the reperfusion period appeared to exacerbate ischemic injury. Infarct size (percent of risk area) was 27.7 +/- 5.6% in vehicle control animals (n = 5), 40.3 +/- 6.2% for cromakalim (n = 5) and 55.7 +/- 6.4% (p less than 0.05 vs. vehicle) for celikalim-treated animals (n = 5). When these compounds were administered intravenously, using doses shown to increase total coronary flow in nonoccluded control animals, no exacerbation of ischemic injury was observed. Anatomic infarct size was 32.8 +/- 7.1% for vehicle animals (n = 5) and 32.6 +/- 13.3 and 30.9 +/- 9.8% for cromakalim- (n = 6) and celikalim-treated (n = 5) animals, respectively. Intravenous diltiazem decreased myocardial infarct size to 16.3 +/- 7.3% (n = 5) of area at risk (p = NS vs. vehicle). The anatomic area at risk was similar in all three treatment groups, and no significant differences in rate-pressure product were observed. Results of this study suggest that K-channel-activating drugs such as cromakalim and celikalim may not be effective agents in the acute therapeutic management of myocardial ischemic injury.

Animals↗
PubMed1992

Hearing preservation in acoustic neuroma surgery: a continuing study.

Hearing preservation in acoustic neuroma surgery is possible in a limited number of cases. Although there have been many articles published about hearing preservation, there have been few studies of long-term hearing results, nor is it known if there is an increased rate of tumor recurrence when hearing preservation is attempted. Twenty-two patients who underwent a hearing preservation procedure via the retrosigmoid approach were selected from 80 consecutive patients with cerebellopontine angle tumors operated on from February 1984 to November 1987. Useful hearing was retained in 11 cases as reported in a previously published study. Seven patients continue to have useful hearing after 3 to 5 years; 3 have shown a gradual but slight decline. There has been no tumor recurrence in these patients, but 2 patients, operated on early in the series and who had lost hearing, had recurrent tumor.

Auditory Threshold↗
PubMed1991

Antithrombotic activity of the phosphodiesterase III inhibitor pelrinone in a canine model of coronary artery thrombosis: enhancement of efficacy with concurrent alpha 2-adrenergic antagonism.

The purpose of this study was to determine if idazoxan, an alpha 2-adrenergic antagonist, could enhance the antithrombotic activity of pelrinone, a PDE III inhibitor, in a canine model of coronary thrombosis that uses electrical current to injure the coronary endothelium. Thrombus mass in vehicle-treated animals was 37.9 +/- 8 mg. Pelrinone, 0.625 and 2.5 mg/kg decreased thrombus size by 46 and 21%, respectively, while idazoxan, 0.75 mg/kg decreased thrombus mass by 43%. When this dose of idazoxan was combined with pelrinone, 0.625 and 2.5 mg/kg, thrombus mass was decreased by 71 and 91%, respectively. Antithrombotic efficacy correlated with the ability of these treatments to inhibit epinephrine-sensitized, collagen-induced platelet aggregation. Sixty minutes following drug administration, idazoxan, 0.50 mg/kg inhibited aggregation by 50%, while pelrinone, 0.625 and 2.5 mg/kg inhibited aggregation by 55 and 68%, respectively. Combined administration of idazoxan with pelrinone, 0.625 and 2.5 mg/kg resulted in 80 and 95% inhibition of aggregation, respectively. Similar trends in inhibiting platelet aggregation to epinephrine-sensitized ADP and arachidonic acid were also observed. Experimental treatments did not affect hematocrit or circulating platelet count, although pelrinone was observed to prolong prothrombin time slightly. To examine the effect of drug-induced increases in coronary blood flow on thrombus formation, the potassium channel activator drug cromakalim was studied at a dose (0.1 mg/kg) that increased coronary blood flow by 25-35 ml/min above baseline in sham control animals. Animals treated with cromakalim showed a shorter time to coronary occlusion (103 +/- 11 min) vs. vehicle (173 +/- 24 min) and developed larger thrombi (53.7 +/- 19 mg). These results demonstrate that coronary vasodilation does not contribute to antithrombotic activity in this model. Results from the study also show that alpha-adrenergic inhibition of platelet function can potentiate phosphodiesterase inhibitor antiaggregatory and antithrombotic activity.

Adenosine Diphosphate↗
PubMed1991

Effect of cold preservation on lymphocyte adherence in the perfused rat liver.

A study was designed to determine if cold preservation induces an increase in lymphocyte adherence to liver sinusoids on reperfusion. Rat livers were stored at 1 degree C in University of Wisconsin solution for 45 min, 8 hr, or 30 hr, and then reperfused for 90 min at 37 degrees C in an isolated perfused rat liver apparatus. Just prior to reperfusion, isogeneic rat lymphocytes prepared on a Ficoll-Paque gradient were added to the perfusate. In some studies lymphocytes were labeled with a fluorescent lipophilic membrane marker. There was no change in the number of circulating lymphocytes in an anhepatic circuit. When livers were present in the circuit, lymphocytes were lost from the perfusate into the liver in all studies, with the most rapid decrease occurring within 10 min of reperfusion. The length of preservation had a marked and statistically significant effect on the rate of disappearance of lymphocytes from the perfusate. Reduction by 50% of the number of lymphocytes infused did not affect the results when expressed as percent lymphocytes remaining in perfusate. To exclude the possibility that the loss of lymphocytes into the liver was due to a damaged subpopulation of lymphocytes, two livers stored 3 for 45 min were put into the circuit in sequence. The percent reduction in cells due to exposure to a second liver was not significantly different from that observed when cells were exposed only to a single liver. Histological studies showed fluorescence-labeled lymphocytes adherent in sinusoids, and the number of labeled cells was directly related to the length of preservation. Cold preservation induces an increase in lymphocyte adherence in the reperfused liver, which might be important in graft malfunction and rejection.

Animals↗
PubMed1991

Structure-function analysis of the rat prolactin promoter: phasing requirements of proximal cell-specific elements.

Expression of PRL, a member of the GH family of genes, is restricted to the lactotroph cells of the anterior pituitary. The proximal promoter of the rat PRL (rPRL) gene contains four factor-binding sites. Three nonadjacent elements, footprints (FP) I, III, and IV, are separated by an integral number of helical turns and bind a pituitary-specific factor, LSF-1. FP II binds another factor present in pituitary and nonpituitary cells. The mechanisms by which DNA-bound proteins influence RNA polymerase-II activity over large distances are not fully understood, but protein-protein interactions, with looping of intervening DNA, may bring distant sites into close proximity. Here, we demonstrate, using protein titration studies, that LSF-1 binds to the most proximal FP I element with the highest affinity, whereas it binds the more distal elements, FP III and FP IV, with progressively lower affinities. Time-course and salt-sensitivity studies reveal that binding of LSF-1 to all three pituitary-specific rPRL promoter sites occurs rapidly (less than or equal to 1 min) and requires fairly high salt concentrations (greater than or equal to 300 mM KCl) to destabilize protein-DNA interactions. Moreover, once bound, the pituitary nuclear factor(s) induces a conformational change in rPRL DNA structure with greatly delayed kinetics (greater than 15 min) and at a different salt concentration than are required for simply factor binding. Taken together, these data suggest a model in which LSF-1 initially binds fairly rapidly to multiple nonadjacent elements and then interacts with itself or other DNA-bound proteins much more slowly, possibly looping or bending the rPRL promoter.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

New estimates of traumatic SCI prevalence: a survey-based approach.

New estimates of traumatic spinal cord injury (SCI) prevalence are developed from a survey specifically designed to identify the SCI population in both institutional and non-institutional settings. The survey utilised a mixed-mode sampling design based on probability sampling methods. Detailed interviews were conducted with SCI persons identified in this survey. We estimate that the traumatic SCI prevalence rate in the United States is 721 cases per million, and that there are about 177,000 SCI persons residing in the United States.

Epidemiologic Methods↗
PubMed1990

Ceranapril (SQ 29,852), an orally active inhibitor of angiotensin converting enzyme (ACE).

Ceranapril (SQ 29,852) is a new inhibitor of angiotensin I (AI) converting enzyme (ACE) belonging to the hydroxylphosphonate class. The purpose of the present report is to present the in vivo pharmacology of ceranapril in conscious animal models. In conscious, normotensive rats, ceranapril administered i.v. (ED50 = 63 nmol/kg) or p.o. (ED50 = 530 nmol/kg) inhibited an AI pressor response with potency equal to that of captopril. However, in conscious dogs, ceranapril was a relatively poor inhibitor of the AI pressor response after both i.v. (ED50 = 300 nmol/kg) and p.o. (ED50 = 18 mumol/kg) administration; in monkeys ceranapril was a good inhibitor of the AI pressor response after i.v. (ED50 = 60 nmol/kg) but not p.o. (ED50 = 18 mumol/kg) administration. In rats, the duration of ceranapril's inhibition of an AI pressor response was longer than an equimolar dose of captopril. Similarly, in SHR, ceranapril's blood pressure lowering effect had a longer duration than that of captopril. Ceranapril's ACE inhibitory effects were longer lasting in anephric rats than in sham rats, suggesting a renal route of excretion for ceranapril. Ceranapril administration to conscious female dogs resulted in significant increases in renal plasma flow and GFR. In SHR, doses of 23 and 68 mumol/kg resulted in significant blood pressure lowering that lasted 24 h. Oral doses of 2.3, 6.8, 23, and 68 mumol/kg in two-kidney, one-clip hypertensive rats resulted in significant and dose-related falls in arterial pressure, which again persisted for 24 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1990

Blood pressure lowering and renal hemodynamic effects of fosinopril in conscious animal models.

The blood pressure lowering and renal hemodynamic effects of fosinopril, the chemically novel inhibitor of angiotensin I converting enzyme (ACE), was assessed in conscious animal models. In conscious dogs, intravenous infusion of SQ 27,519 [0.5 mg/kg (1.1 mumol/kg) bolus plus 0.1 mg/kg/min (0.22 mumol/kg/min)], the active moiety of the prodrug fosinopril, increased PAH clearance and GFR by 25 and 16%, respectively (p less than 0.05, each) without changing arterial pressure (AP). Urine volume, sodium excretion, and potassium excretion were elevated, although not significantly increased. In sodium-depleted cynomolgus monkeys, 1.5 and 5.0 mumol/kg (0.88 and 2.9 mg/kg) p.o. of fosinopril lowered arterial pressure from 115 +/- 5 to 99 +/- 5 mm Hg and from 116 +/- 3 to 87 +/- 4 mmHg, respectively (p less than 0.05, each). When given orally to SHR at 10 and 30 mg/kg (5.9 and 17.6 mumol/kg), fosinopril lowered AP by 23 (183 +/- 4 to 160 +/- 5 mm Hg) and 20 mm Hg (176 +/- 4 to 156 +/- 4 mm Hg), respectively. The combination of fosinopril [10 mg/kg (5.9 mumol/kg)] plus hydrochlorothiazide (10 mg/kg) reduced AP from 206 +/- 4 to 167 +/- 2 mm Hg when given orally to SHR. Fosinopril was more effective in two-kidney, one-clip hypertensive rats relative to SHR; AP fell from 201 +/- 9 to 160 +/- 7 mm Hg after 10 mg/kg (5.9 mumol/kg), and from 205 +/- 7 to 145 +/- 7 mm Hg after 30 mg/kg (17.6 mumol/kg).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Sagittal plane analysis in idiopathic scoliosis patients treated with Cotrel-Dubousset instrumentation.

One hundred sixty patients with idiopathic scoliosis treated with Cotrel-Dubousset instrumentation (CDI) underwent preoperative and postoperative sagittal plane analysis of the thoracic spine, thoracolumbar junction, and lumbar spine. The data suggest that mild to moderate improvements in thoracic hypokyphosis are possible. When crossing the thoracolumbar junction, reversal of rod bend and reversal of hooks on the derotation rod appear to provide the most physiologic sagittal contour. Cotrel-Dubousset instrumentation to the mid and distal lumbar spine can preserve and, at times, enhance lumbar lordosis.

Humans↗
PubMed1990

Sagittal plane analysis in idiopathic scoliosis patients treated with Cotrel-Dubousset instrumentation.

One hundred sixty patients with idiopathic scoliosis underwent preoperative and postoperative sagittal plane analysis of the thoracic spine, thoracolumbar junction, and lumbar spine. The data suggest that mild to moderate improvements in thoracic hypokyphosis are possible. When crossing the thoracolumbar junction, reversal of rod bend and reversal of hooks on the derotation rod appears to provide the most physiologic sagittal contour. Cotrel-Dubousset instrumentation to the mid and distal lumbar spine can preserve and, at times, enhance lumbar lordosis.

Adolescent↗
PubMed1990

Controlled trial of natamycin in the treatment of allergic bronchopulmonary aspergillosis.

Allergic bronchopulmonary aspergillosis often requires treatment with oral corticosteroids to control the host response to Aspergillus fumigatus. In a double blind study 25 patients with allergic bronchopulmonary aspergillosis taking maintenance oral corticosteroids were randomly allocated to receive 5 mg natamycin or placebo by nebuliser twice daily for one year. The primary aim of the study was to assess the steroid sparing potential of natamycin. Standardised reductions in corticosteroid dosage were therefore undertaken every five weeks, unless clinically contraindicated. Five patients were withdrawn in the first four months: two (1 natamycin, 1 placebo) died, two (1 natamycin, 1 placebo) had suspected drug reactions, and one (natamycin) was non-compliant. The pretreatment characteristics of the 20 patients (10 in each group) who completed the study were similar, 17 (9 natamycin, 8 placebo) having evidence of recent disease activity. At the end of the study prednisolone dose had been reduced by a similar amount in each group (median natamycin 2.25 mg, placebo 2.5 mg). Evidence of disease activity during the study year (transient shadowing on the chest radiograph, blood eosinophilia, or increases in antibodies to A fumigatus, or any combination of these) was observed in similar numbers of patients in each group (5 natamycin, 7 placebo). There was no evidence that natamycin conferred benefit on these patients with allergic bronchopulmonary aspergillosis.

Adult↗
PubMed1989

Predicting relapse in schizophrenia: the development and implementation of an early signs monitoring system using patients and families as observers, a preliminary investigation.

Recognition of prodromal symptoms of schizophrenia offers the potential of early intervention to avert relapse and re-hospitalization (Carpenter & Heinrichs, 1983). The present study investigated how a strategy to detect prodromal signs might be effectively applied in the clinical setting. A standard monitoring system was developed involving completion of a new early signs scale (ESS) measuring changes in key symptoms phenomenologically (self-report) and behaviourally (observer report). The ESS was subject to rigorous psychometric evaluation and tested in a prospective pilot investigation. The ESS reliably identified early signs and predicted relapse with an overall accuracy of 79%. Several different patterns of relapse were identified. Observer reports compensated for loss of insight in some patients. In two cases where early signs indices were detected, prompt increases in medication appeared to arrest relapse and avert readmission. The ESS offers itself as a reliable, valid and administratively feasible measure and demonstrates considerable potential as a cost-effective procedure for secondary prevention.

Adult↗
PubMed1989

Fosinopril, a phosphinic acid inhibitor of angiotensin I converting enzyme: in vitro and preclinical in vivo pharmacology.

Fosinopril is the first member of a new chemical class of angiotensin I (AI) converting enzyme (ACE) inhibitors, the phosphinic acids. In vitro, SQ 27,519, the active moiety of the prodrug fosinopril, was a more potent inhibitor of purified rabbit lung ACE- (IC50 = 11 vs. 23 nM) and bradykinin-induced contractions of guinea pig ileum than captopril. In vivo, SQ 27,519 was equipotent to captopril as an inhibitor of an AI pressor response after intravenous (i.v.) administration to conscious rats and monkeys but appeared to be less potent in conscious dogs. After oral administration, fosinopril again was equipotent to captopril as an inhibitor of an AI pressor response in rats and monkeys and slightly less potent in dogs. However, both SQ 27,519 (i.v. studies) and fosinopril (oral studies) had a longer effect than captopril in all three species. When fosinopril was administered orally for 5 days, its effects on an AI pressor response were the same on days 1 and 5, suggesting lack of tolerance to the compound. The ACE inhibitory effect of captopril, but not fosinopril, was prolonged in conscious rats with glycerol-induced acute renal failure, suggesting that fosinopril is excreted by an extrarenal route. Finally, fosinopril had no effect on the pressor or chronotropic effects of norepinephrine (NE) or 1,1-dimethyl-4-phenylpiperinium (DMPP) or electrical stimulation of the sympathetic ganglia of pithed rats. Fosinopril attenuated the pressor, but not the chronotropic effects of tyramine. We conclude that fosinopril is a potent and long-lasting inhibitor of ACE in conscious animal models that does not impair adrenergic function or reflexes.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗
PubMed1989

Characterization of immunologically important antigens and allergens of Aspergillus fumigatus.

Using a variety of immunochemical methods, including quantitative immuno-electrophoretic techniques, combined with gel filtration and iso-electric focusing, and production of monospecific antisera for identification and affinity purification, 4 major components of Aspergillus fumigatus have now been partially characterized. Numbering of these was derived from a reference allergic bronchopulmonary aspergillosis (ABPA) self-crossed radio-immuno-electrophoresis pattern of reactivity. Two major intracellular/cytoplasmic, concanavalin A (Con A)-binding antigens, Ag 7 and Ag 13, of molecular weights 150-200 and 70 kilodaltons (kD), respectively, were confirmed to be of importance for both ABPA and aspergilloma in specific sandwich enzyme-linked immunosorbent assays. A rapidly released component, Ag 5, of molecular weight 35 kD, proved both antigenic and allergenic, with aspergilloma patients having especially high-titre IgG antibodies. The major allergenic component Ag 3, of molecular weight 24 kD by gel filtration and 18 kD by SDS-PAGE was, like Ag 5, relatively heat-labile and non-Con-A-binding. Interestingly, T cell clones have been identified which respond primarily to an 18-kD fraction.

Allergens↗