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Biomedical subjects

A D Kaye

Publications and source records attributed to A D Kaye.

At least 19 recordsLinked to original sources
PubMed2004

Peroxynitrite does not impair pulmonary and systemic vascular responses.

The effects of peroxynitrite (ONOO-) on vascular responses were investigated in the systemic and hindquarters vascular bed and in the isolated perfused rat lung. Intravenous injections of ONOO- decreased systemic arterial pressure, and injections of ONOO- into the hindquarters decreased perfusion pressure in a dose-related manner. Injections of ONOO- into the lung perfusion circuit increased pulmonary arterial perfusion pressure. Responses to ONOO- were rapid in onset, short in duration, and repeatable without exhibiting tachyphylaxis. Repeated injections of ONOO- did not alter systemic, hindquarters, or pulmonary responses to endothelium-dependent vasodilators or other vasoactive agonists and did not alter the hypoxic pulmonary vasoconstrictor response. Injections of sodium nitrate or nitrite or decomposed ONOO- had little effect on vascular pressures. Pulmonary and hindquarters responses to ONOO- were not altered by a cyclooxygenase inhibitor in a dose that attenuated responses to arachidonic acid. These results demonstrate that ONOO- has significant pulmonary vasoconstrictor, systemic vasodepressor, and vasodilator activity; that short-term repeated exposure does impair vascular responsiveness; and that responses to ONOO- are not dependent on cyclooxygenase product release.

Anesthesia↗
PubMed2003

Ephedrine in the cat lung vasculature.

BACKGROUND: Ephedrine is one of the most commonly used non-catecholamine sympathomimetic agents. It is used in operating rooms and critical care settings worldwide. While it has many side effects, its ability to rapidly raise blood pressure makes it an ideal agent to maintain homeostasis as well as in emergency situations. While its effects are known to be mediated by an alpha-mediated mechanism, the exact alpha subtype is unknown. In addition, no studies using ephedrine have been performed in the pulmonary vascular bed of the cat. METHODS: The effects of phentolamine, a non-selective alpha-receptor blocker, and prazosin, an alpha1-selective antagonist, were investigated on pulmonary arterial responses to ephedrine, phenylepherine, norepinephrine, and U-46619. Lobar arterial perfusion pressure was continuously monitored, electronically averaged, and recorded with constant flow in the isolated left lower lobe vascular bed of the cat. RESULTS: Phentolamine and prazosin significantly reduced vasoconstrictor pulmonary perfusion pressure increases induced by ephedrine. CONCLUSION: Ephedrine has significant vasopressor activity in the pulmonary vascular bed of the cat meditated predominantly by alpha1 adrenergic receptor activation.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed2003

Recovery of elderly patients from two or more hours of desflurane or sevoflurane anaesthesia.

BACKGROUND: The solubility of desflurane compared with sevoflurane suggests more rapid recovery from desflurane anaesthesia. This could be important after prolonged anaesthesia and fast recovery may be advantageous in the elderly where slow recovery of mental function is a concern. We compared emergence from desflurane vs sevoflurane in elderly patients undergoing two or more hours of anaesthesia. METHODS: Fifty ASA physical status I, II, or III patients, 65 yr of age or older, undergoing anaesthesia expected to last two or more hours were randomly assigned to receive desflurane/nitrous oxide or sevoflurane/nitrous oxide anaesthesia. Patients were given 1-2 microg x kg(-1) fentanyl i.v. and anaesthesia was induced with propofol 1.5-2.5 mg x kg(-1) i.v. and maintained with either desflurane 2-6% or sevoflurane 0.6-1.75% with nitrous oxide 65% in oxygen. Inspired anaesthetic concentrations were adjusted to obtain adequate surgical anaesthesia and to maintain mean arterial pressure within 20% of baseline values. Early and intermediate recovery times were recorded. Digit-Symbol Substitution Test (DSST) scores and Visual Analog Scale (VAS) scores for pain and nausea were recorded before pre-medication and every 15 min in the Post Anaesthesia Care Unit (PACU) until patients were discharged. RESULTS: Early recovery times are given as median, quartiles. The times to extubation (5 (4-9); 9 (5-13) min), eye opening (5 (3-5); 11 (8-16) min), squeezing fingers on command (7 (4-9); 12 (8-17) min); and orientation (7 (5-9); 16 (10-21) min) were significantly less (P<0.05) for desflurane than for sevoflurane. Intermediate recovery, as measured by the DSST and time to ready for discharge from the PACU (56 (35-81); 71 (61-81) min) was similar in the two groups. CONCLUSIONS: Early but not intermediate recovery times of elderly patients undergoing a wide range of surgical procedures requiring two or more hours of anaesthesia is significantly (P<or=0.05) faster after desflurane.

Aged↗
PubMed2001

Comparison of responses to novel nitric oxide donors in the feline pulmonary vascular bed.

Pulmonary vascular responses to the novel diazeniumdiolate nitric oxide (NO) donors diethylamine/NO, diethylenetriamine/NO, spermine/NO, sulfite/NO, and angeli's salt, were investigated and compared in the intact-chest cat. Under conditions of controlled blood flow, when tone in the pulmonary vascular bed had been raised to a high steady level, intralobar injections of diethylamine/NO (0.3-10 microg), diethylenetriamine/NO (10-30 microg), spermine/NO (10-30 microg), sulfite/NO (10-30 microg), and angeli's salt (10-30 microg) caused dose-related decreases in lobar arterial pressure without changing left atrial pressure. In terms of relative vasodilator activity in the pulmonary vascular bed, the dose of the compounds that decreased lobar arterial pressure 4 mm Hg (ED(4) mm Hg) was significantly lower for diethylamine/NO compared to S-nitroso-N-acetylpenicillamine which was significantly less than diethylenetriamine/NO, spermine/NO, sulfite/NO, and angeli's salt. The half-life of the vasodilator responses, as measured by 50% response recovery time, to diethylamine/NO, diethylenetriamine/NO, spermine/NO, sulfite/NO, and angeli's salt was similar for doses with similar magnitudes of vasodilation, while the half-life to S-nitroso-N-acetylpenicillamine was significantly less than the diazeniumdiolate NO donors. The present data demonstrate that the diazeniumdiolate NO donors diethylamine/NO, diethylenetriamine/NO, spermine/NO, sulfite/NO, and angeli's salt have potent but relatively short-lasting vasodilator activity in the pulmonary vascular bed of the cat.

Animals↗
PubMed2001

"Wiener klinische Wochenschrift": publication patterns 1990-2000.

The impact factor (Institute for Scientific Information, ISI, Philadelphia, PA, USA) is a widespread used and acknowledged source for judging the quality of a researcher. In addition the "Science Citation Index (SCI)" [Institute for Scientific Information (ISI)] provides the scientific community with a citations database indicating the number of cited references in indexed articles. For several reasons, the SCI seems to be more relevant. To evaluate the quality of the journal "Wiener klinische Wochenschrift", we assessed how often contributors to this journal have been cited during the last decade and which contributions have ranked as top papers. Moreover, with the aim of a more objective type of scientific evaluation, we have employed a new score, the "Citation Per Time Score (CPT-Score--the SCI divided by the number of years of observation, starting one year after publication). We have evaluated the total SCI for the years 1990 to 1994 and for the years 1995 to 1999. The number of total citations between the appearance of an article and the year 2000 was analyzed. The highest ranked publication of the whole decade (1990-2000) was a paper by G. Stanek with 40 citations. Furthermore, we have evaluated the "Top Ten Papers" of the journal. Interestingly, a steady increase of the total citation index of the journal "Wiener klinische Wochenschrift" over the last decade could be demonstrated. This study clearly shows that the citation rate of an article is not determined by the impact factor of the journal but rather the quality of the contribution. Moreover, the citation analysis of papers published in the last ten years in the "Wiener klinische Wochenschrift" shows a satisfactory citation rate for articles published in this journal. It is therefore definitely attractive to submit an article to a journal such as the "Wiener klinische Wochenschrift".

Austria↗
PubMed2001

Effects of PKC isozyme inhibitors on constrictor responses in the feline pulmonary vascular bed.

The effects of Gö-6976, a Ca(2+)-dependent protein kinase C (PKC) isozyme inhibitor, and rottlerin, a PKC-delta isozyme/calmodulin (CaM)-dependent kinase III inhibitor, on responses to vasopressor agents were investigated in the feline pulmonary vascular bed. Injections of angiotensin II, norepinephrine (NE), serotonin, BAY K 8644, and U-46619 into the lobar arterial constant blood flow perfusion circuit caused increases in pressure. Gö-6976 reduced responses to angiotensin II; however, it did not alter responses to serotonin, NE, or U-46619, whereas Gö-6976 enhanced BAY K 8644 responses. Rottlerin reduced responses to angiotensin II and NE, did not alter responses to serotonin or U-46619, and enhanced responses to BAY K 8644. Immunohistochemistry of feline pulmonary arterial smooth muscle cells demonstrated localization of PKC-alpha and -delta isozymes in response to phorbol 12-myristate 13-acetate and angiotensin II. Localization of PKC-alpha and -delta isozymes decreased with administration of Gö-6976 and rottlerin, respectively. These data suggest that activation of Ca(2+)-dependent PKC isozymes and Ca(2+)-independent PKC-delta isozyme/CaM-dependent kinase III mediate angiotensin II responses. These data further suggest that Ca(2+)-independent PKC-delta isozyme/CaM-dependent kinase III mediate responses to NE. A rottlerin- or Gö-6976-sensitive mechanism is not involved in mediating responses to serotonin and U-46619, but these PKC isozyme inhibitors enhanced BAY K 8644 responses in the feline pulmonary vascular bed.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed2001

Postoperative nausea and vomiting--a review.

Post operative nausea and vomiting (PONV) remains an unpleasant and persistent problem for patients undergoing surgery. In fact PONV are among the most important factors contributing to delay in discharge of patients and an increase in unanticipated admissions after ambulatory surgery. Anesthesia providers are most often blamed for PONV, sometimes rightfully so, many times wrongly so. PONV is a multifactorial issue involving many physiological and biological mechanisms. As the trend towards ambulatory surgery increases, PONV continues to pose serious challenges for anesthesia providers because the potential cost savings of performing surgeries on an ambulatory basis may be negated by unanticipated hospital admission. Although PONV may be unavoidable in some patients for reasons we do not fully understand, there are risk factors that can be identified. As anesthesiologists it is essential for us to understand the mechanisms involved in nausea and vomiting and the available perioperative treatment options. We must do whatever we can to prevent and treat PONV and improve patient outcome for both medical and economic reasons.

Anesthetics↗
PubMed2001

Perioperative considerations for the patient on herbal medicines.

Herbal medicines have enormous presence in the United States health care system. There is an increasing trend towards reimbursement of herbal medicines by insurance companies, which further encourage their utilization. Herbs are listed under the "supplement" category by the Food and Drug Administration. The Dietary Supplement and Health Education Act signed into law in October 1994, requires no proof of efficacy, no demonstration of safety, and sets no standards for quality control for the products labeled as "supplements" thereby increasing the risk of adverse effects of these herbs. The United States has experienced an epidemic of over-the-counter "natural" products over the last two decades; but there is little motivation for the manufactures to conduct randomized, placebo-controlled, double-blinded clinical trials to unequivocally prove the safety and efficacy of these drugs. Physicians, irrespective of their specialty, should not underestimate the potential risks associated with the use of herbs as reports indicate that within the last two decades, more than 100 herbogenic deaths have occurred, many serious complications have been reported, patients have required renal dialysis, renal transplantation and hepatic transplantation after taking botanicals. Internists must inquire about the patient's use of herbal products. In addition, the education of each patient regarding the serious, potential drug-herb interactions should be a routine component of preoperative assessment. The American Society of Anesthesiologists (ASA) recommends that all herbal medications should be discontinued 2-3 weeks prior to an elective surgical procedure. If the patient is not sure of the content of the herbal medicine, he/she should be urged to bring the container so that an attempt can be made to review the contents of the preparation. While such an action holds some promise in the elective setting, emergency care should be based on a thorough drug-intake history from the patient or a relative, if possible. Medical research and medical literature in general has not addressed this new group of health supplements, despite the fact that many of these herbs have the potential to cause serious health problems and drug interations. There is a need to conduct scientific clinical trials to study the anesthetic drug responses to commonly used neutraceutical agents.

Aged↗
PubMed2000

Prostaglandin E(1) is able to increase migration of leukocytes through endothelial cell monolayers.

Leukocyte interactions with endothelial cells play an important role during inflammatory processes. Leukocytes pass a monolayer of endothelial cells (ECM) to migrate into the extravascular space. The aim of the current study was to investigate whether prostaglandin E(1) (PGE(1)) influences the process of leukocyte migration. In a prospective controlled study, the influence of prostaglandin E(1) (50-5000 ng/mL) on leukocyte migration through endothelial cell monolayers (n = 7) was investigated. Human umbilical endothelial cells (HUVEC) and/or leukocytes were preincubated with clinically relevant, higher, and lower concentrations of prostaglandin E(1) and the amount of leukocyte migration after 3 h was measured. HUVEC were cultured on microporous membrane filters until achievement of a monolayer for investigation of leukocyte migration. Polymorphonuclear leukocytes (PMNL) were isolated from healthy volunteers and PMNL migration was studied under the influence of PGE(1). In clinically relevant concentrations, PGE(1) was able to increase significantly leukocyte migration through endothelial cell monolayers (205 +/- 7.8%, P < 0.05 compared to control; when treating PMNL alone, migration rate was 120 +/- 9.2% compared to control, ns; only endothelial cell monolayers treated up to 145 +/- 10.2%, P < 0.05 compared to control) showing a dose-dependent effect. In this assay, both cell types (PMNL and ECM) could be treated simultaneously, simulating the clinical situation after an iv administration. In conclusion, PGE(1) is able to increase leukocyte migration through endothelial cell monolayers when both cell types are pretreated. The treatment of either leukocytes or endothelial cell monolayers in the cell coculture showed no significant increase. These findings support the theory that prostaglandins may play a major role during inflammation. Future clinical studies are warranted to confirm this hypothesis.

Adult↗
PubMed2000

Phenotypic expression of the systemic toxicity of cocaine in genetically epilepsy-prone rats.

The purpose of the present investigation was to determine whether the sensitivity to systemic toxic effects of cocaine is altered in genetically epilepsy-prone rats (GEPRs). Moderate seizure (GEPR-3) and severe seizure (GEPR-9) rats, and the control strain, Sprague-Dawley rats, 10 weeks of age, were lightly anesthetized with halothane and nitrous oxide. Following surgical preparation and stabilization, the animals were given a constant intravenous infusion of cocaine (4 mg/kg per min) until death. Blood pressure, ECG, and EEG were monitored continuously throughout the experiment. Cocaine doses required to produce seizures (i.e., epileptiform activity on the EEG) were not significantly different between GEPRs and control rats (16.8+/-0.6 mg/kg in GEPR-3, 18.7+/-0.7 mg/kg in GEPR-9, and 14.7+/-1.3 mg/kg in Sprague-Dawley). Seizure duration, amplitude and the number of epileptiform bursts were also similar among the three strains. Additionally, there was no significant difference in cocaine doses that produced arrhythmias and cardiac asystole between GEPRs and control. The results indicate that genetically epilepsy-prone rats do not exhibit altered sensitivity to cocaine-induced seizures despite the marked susceptibility to sound-evoked seizures. Local anesthetic-induced seizures and acoustically-evoked seizures apparently have different underlying mechanisms.

Animals↗
PubMed2000

Herbal medicines: current trends in anesthesiology practice--a hospital survey.

STUDY OBJECTIVES: To develop a simple survey to determine the patient population actively utilizing dietary supplements and/or herbs, during the preoperative period. DESIGN: Prospective study, with survey instrument. SETTING: University medical center. PATIENTS: 1,017 patients presenting for preanesthetic evaluation prior to outpatient surgery. INTERVENTIONS: After undergoing preanesthetic evaluation, patients were asked to complete a survey listing which of the nine most popular nutraceuticals currently available on the market they were using. MEASUREMENTS AND MAIN RESULTS: A total of 1017 surveys were submitted over a period of five months, with 32% being poorly completed and thus discarded. Of the remaining 755 valid surveys, 482 patients used at least one nutraceutical agent. 90% of these patients were using vitamins, 43% garlic extracts, 32% Gingko Biloba, 30% St. John's Wort, 18% Ma Huang, 12% Ecchinaceae, 10% Aloe, 8% Cascare, 3% licorice. CONCLUSION: A significant population of patients scheduled for an elective surgical procedure are self-administering nutraceutical agents. Some of these agents have the potential to cause serious drug interactions and hemodynamic instability during surgery. Hence, it may be important to identify patients self-administering these medications, during the preoperative period.

Adolescent↗
PubMed2000

Effects of remifentanil on neutrophil adhesion, transmigration, and intercellular adhesion molecule expression.

BACKGROUND: Anaesthetic drugs are used for pain therapy and anaesthesia. Neutrophils play a significant role during the process of inflammation. The aim of the current study was to investigate the effects of remifentanil and fentanyl on neutrophil migration through endothelial cell monolayers, and on adhesion molecule expression. METHODS: After isolation of polymorphonuclear neutrophils (PMNL) we used a currently described migration assay. PMNL and/or endothelial cell monolayers (ECM) were pre-treated with remifentanil using clinically relevant, as well as higher and lower concentrations or relevant concentrations of fentanyl. RESULTS: Concentrations of remifentanil (50 ng/mL) similar to the relevant plasma concentration were able to inhibit PMNL migration through ECM significantly (migration compared to the control 82+/-7% SD; P<0.05), when both cell types were treated with the synthetic narcotic remifentanil. Fentanyl (30 ng/mL) showed a stronger inhibitory effect (migration compared to the control 67+/-9.2%; P<0.05). Endothelial cell adhesion molecule expression was reduced after either remifentanil or fentanyl. CONCLUSION: The results of the present investigation indicate that remifentanil influences interaction of ECM against human neutrophils. Compared to fentanyl, remifentanil seems to exhibit minor inhibitory effects on neutrophil migration.

Analgesics, Opioid↗
PubMed2000

Thrombus formation on the balloon of heparin-bonded pulmonary artery catheters: an ultrastructural scanning electron microscope study.

OBJECTIVE: To investigate heparin-bonded pulmonary artery catheters with respect to thrombus formation and platelet aggregation at the balloon and the shaft using a scanning electron microscope in critically ill patients. DESIGN: Prospective study. SETTINGS: Critical care unit and research laboratories. PATIENTS: Pulmonary artery catheters were inserted in critically ill patients (n = 10). INTERVENTIONS: Pulmonary artery catheters were removed after 24, 48, 72, or 120 hrs, and the ultrastructure was investigated in specialized research laboratories. MEASUREMENTS AND MAIN RESULTS: Balloon and shaft were investigated using a scanning electron microscopic technique. Area of thrombus formation was quantified using image analysis. Heparin release of the catheters was measured. The frequency of balloon inflations was investigated in in vitro experiments by inflating catheters different times (0, 10, 20, and 30 times). Twenty-four hours after catheter insertion, scanning electron microscopic images showed thrombus formation and platelet aggregation at the site of the balloon. Seventy-two hours after catheter insertion, a thrombus started to detach. The areas of thrombus formation did not differ, but thrombus organization changed dramatically 72 and 120 hrs after catheter insertion. The shaft was colonized by single cells only. Cracks of the balloon could be observed after 72 hrs, whereas no cracks could be found in in vitro controls. In vitro, heparin release of the pulmonary artery catheters decreased significantly after 24 hrs. CONCLUSIONS: Scanning electron microscopic images of heparin-bonded pulmonary artery catheters demonstrate thrombus formation on the balloon 24 hrs after pulmonary artery catheter insertion, increasing dramatically at 72 and 120 hrs. The shaft was colonized by single cells only. The thrombus size is not significantly different during the observation time, but the grade and quality of thrombus formation differ.

Anticoagulants↗
PubMed2000

Analysis of ketamine responses in the pulmonary vascular bed of the cat.

OBJECTIVE: To test the hypothesis that pulmonary vasodilator responses of ketamine are dependent on activation of L-type calcium channels, independent of synthesis of nitric oxide from L-arginine, activation of adenosine triphosphate-sensitive potassium channels, and the release of cyclooxygenase products. DESIGN: Prospective study. SETTING: Research laboratory. SUBJECTS: Isolated lobar lung preparation, mongrel cats. INTERVENTIONS: In separate experiments, the effects of nicardipine; N omega-I-nitro-L-arginine methyl ester, an inhibitor of nitric oxide synthase; glibenclamide, an adenosine triphosphate-sensitive potassium channel antagonist; and meclofenamate, a cyclooxygenase blocker, were investigated in the pulmonary vascular bed of the cat. The effects of these agents were evaluated on the pulmonary arterial responses of ketamine, acetylcholine, and isoproterenol during elevated tone conditions induced by the thromboxane A2 mimic, U46619 (Upjohn, Kalamazoo, MI). MEASUREMENTS: Lobar arterial perfusion pressure, systemic pressure, and left atrial pressure were continuously monitored, electronically averaged, and permanently recorded. MAIN RESULTS: Under elevated tone conditions in the isolated left lower lobe vascular bed of the cat, N omega-I-nitro-L-arginine methyl ester, glibenclamide, and meclofenamate had no significant effect on the vasodilator responses to ketamine. Nicardipine, in a dose that reduced significantly vasopressor effects to BAY K 8644, a calcium-channel opener, attenuated significantly vasodilator responses to ketamine, whereas the L-type calcium-channel blocker had no significant effects on responses to acetylcholine and to isoproterenol. CONCLUSIONS: These data show that ketamine has significant vasodilator activity in the pulmonary vascular bed of the cat. The present data also suggest that responses to ketamine during elevated tone conditions may in part be mediated by the activation of L-type calcium channels.

Analgesics↗