Search PubMed⌕ Search

Biomedical subjects

O Prakash

Publications and source records attributed to O Prakash.

At least 19 recordsLinked to original sources
PubMed1992

Continuous intra-arterial PO2 monitoring during thoracic surgery.

Intermittent blood gas sampling has several disadvantages, the most important being that samples are usually taken at set intervals, or when changes in oxygenation are suspected--when it is too late. Another problem is inaccuracy caused by careless blood sample handling. Continuous intravascular PaO2 monitoring eliminates these problems. This study shows that the Continucath sensor is an easy-to-use and reliable monitor, with specific early warning capabilities for hypoxia, thereby improving anesthetic and intensive care management. Its characteristics are: a stabilization period of 10 minutes, a 90% response time of 90 seconds, temperature dependence of 4% per degree celsius, a flow dependence of less than 1% if the flow is more than 5 cm/sec, a drift of less than 0.7% per hour, a correlation coefficient of 0.92 when compared to blood gas analysis during surgery.

Adult↗
PubMed1992

Real-time respiratory monitoring workstation--software and hardware engineering aspects.

We have applied advanced real-time techniques in software, that are intensively used in critical areas like space research and defence applications, to realise an Integrated Real-Time Respiratory Monitoring System at the Thorax Anesthesiology, Academic Hospital Rotterdam. The system is called the 'SERVO WINDOW'--a window to the servo ventilator. The heart of the system is a real-time kernel that uses preemptive scheduling to achieve multitasking on a IBM PC compatible hardware platform. To the clinician this means that he gets all relevant information from one source i.e. the Respiratory Workstation. The waveforms of the airway pressure, airway flow and the expired CO2 curve are displayed continuously on the screen. The Vector Loops like Pressure Volume, Flow Pressure and Flow Volume loops are also available in addition to the lung mechanics parameters like Expiratory and Inspiratory Resistances, Compliances, Peak Pressure, PEEP, etc. The Single Breath Diagram i.e. expired CO2 concentration versus volume and dead space ventilation is also calculated. The blood gas analysis data is plotted in convenient diagrams like the O2-CO2 diagram, Oxygen Chart, etc. The trend of all these parameters are available with a granularity of one minute. An industry standard laser printer is used for report generation to produce reports of the real-time waveforms, parameter values and the trends. User interface is through easy menus with the traditional keyboard, touchscreen including keyboard on screen for data entry and the mouse.

Computer Systems↗
PubMed1992

Comparison of ketorolac and morphine for postoperative pain after major surgery.

This study was designed to determine the relative analgesic efficacy and safety of single intramuscular injections of ketorolac (10 mg or 30 mg) and morphine (10 mg) in patients of either sex with moderate to severe pain after major surgery. In a single-dose, randomised, double-blind study of parallel design, pain was assessed immediately before injection of test medication and at regular intervals for 8 h thereafter. One hundred and seventeen patients (109 undergoing cardiac surgery; 8 lung surgery) were randomized to one of the three treatment groups. Pain intensity was assessed using a 5-point verbal scale before administration of study drugs. Postadministration, at 30 min and hourly for 8 h, pain intensity and pain relief were assessed, again using the 5-point verbal scale. Additionally, as a measure of analgesia, forced expiratory volume (FEV1) was obtained in all patients. Vital signs including blood pressure, pulse, temperature, respiratory rate and blood gases (PaCO2) were recorded prior to and after study medication. Based on hourly pain intensity differences and hourly pain relief observations, ketorolac 10 mg was generally more effective than morphine 10 mg, and ketorolac 30 mg was generally more effective than ketorolac 10 mg. The results of this study show that ketorolac is an effective and safe (with regard to arterial pressure, blood gases and lung function) analgesic for relief of postoperative pain after major surgery in stable patients. No clinically significant adverse effects occurred during the study. One cannot exclude an influence on patients with organ system dysfunction or on parameters not measured in this study.

Adult↗
PubMed1991

Topographical requirements for delta-selective opioid peptides.

The conformational possibilities of three different delta-selective opioid peptides, which are DPDPE (Tyr-D-Pen-Gly-Phe-D-Pen), DCFPE (Tyr-D-Cys-Phe-D-Pen), and DRE (Tyr-D-Met-Phe-His-Leu-Met-Asp-NH2, dermenkephalin), were explored using energy calculations. Sets of low-energy conformers were obtained for each of these peptides. The sets consisted of 61 structures for DPDPE, 32 for DCFPE, and 38 for DRE, including various types of rotamers of the Tyr and Phe side-chain groups. Comparison of the geometrical shapes of the conformers was performed for these sets using topographical considerations, i.e., examination of the mutual spatial arrangement of the N-terminal alpha-amino group, and of the Tyr and Phe side-chain groups. The results obtained suggest a model for the delta-receptor-bound conformer(s) for opioid peptides. The model suggests the placement of the Phe side chain in a definite position in space corresponding to the g- rotamer of Phe for peptides containing Phe4 and to the t rotamer for peptides containing Phe. The position of the Tyr1 side chain cannot be specified so precisely. The proposed model is in a good agreement with the results of biological testing of beta-Me-Phe4-substituted DPDPE analogues that were not considered in the process of model construction.

Amino Acid Sequence↗
PubMed1991

c-myc and K-ras-2 oncogenes in B-cell chronic lymphocytic leukemia with del(12)(p13).

Molecular and cytogenetic analyses were performed on chronic B-lymphocytic cell leukemia (CLL) from a 57-year-old male patient with del(12)(p13) anomaly. The deletion did not remove the K-ras-2 gene. However, c-myc gene amplification correlated with high-level expression, suggesting the involvement of this gene in the induction of neoplasia in this patient.

Chromosome Deletion↗
PubMed1991

Immediate hypersensitivity to Parthenium hysterophorus. II. Clinical studies on the prevalence of Parthenium rhinitis.

The airborne pollen of the South American weed, Parthenium hysterophorus (American feverfew), accidentally introduced into India was found to be responsible for severe allergic rhinitis. A random clinical survey conducted on 2035 residents of Bangalore city with the aid of questionnaires and skin tests revealed that 7.1% of the study population was suffering from allergic rhinitis due to exposure to Parthenium pollen. Skin-prick tests performed on 1294 clinic patients suffering from nasobronchial allergy during the past 4 years have also shown that 42.5% were sensitive to Parthenium pollen. IgE and IgG antibodies specific for Parthenium pollen allergens were demonstrable in the sera of Parthenium-sensitive rhinitis patients. The specificity of these antibodies to Parthenium allergens was established by ELISA. A 7- to 11-fold higher stimulation was observed when lymphocytes from two Parthenium-sensitive rhinitis patients were treated in vitro with Parthenium pollen extract. To our knowledge, nowhere in the world has such a high incidence of allergic rhinitis due to a single pollen ever been reported.

Adolescent↗
PubMed1991

Transactivation of human immunodeficiency virus type 1 long terminal repeats by cell surface tumor necrosis factor alpha.

Tumor necrosis factor alpha (TNF-alpha) is expressed in secreted and cell surface (csTNF-alpha) forms by activated monocytic and T cells. In this report, we demonstrate that csTNF-alpha may predominantly regulate the human immunodeficiency virus type 1 (HIV-1) long terminal repeat (LTR) activation in the promonocytic cell line U937 and in the Epstein-Barr virus-transformed B-cell line BH1. Anti-TNF-alpha antibody suppressed both the constitutive expression of the HIV-1 LTR in BH1 cells and the expression induced by phorbol 12-myristate 13-acetate in U937 cells. This suppression was found to be mediated via csTNF-alpha. No correlation between the HIV-1 LTR activation and the secretion of TNF-alpha was evident in these cell lines. Suppression of TNF-alpha secretion by cyclosporin A or by a serine protease inhibitor did not suppress the HIV-1 LTR activation. These observations suggest a novel biological role for csTNF-alpha in the immunopathogenesis of AIDS.

Cell Line↗
PubMed1991

Angiotensin-converting enzyme inhibition reduces neuroblastoma cell growth rate.

Because of the known capacity of angiotensin II to serve as a growth factor in multiple tissues, we elected to study the effects of renin-angiotensin system inhibition on the growth of human SH-SY5Y neuroblastoma cells. Cells were treated with captopril (0.05-5 mg/ml), enalapril, or enalaprilat (0.02-5 mg/ml) or saralasin (0.1-0.25 mg/ml). In all cases, statistically significant reductions in cell growth were seen over 5 days of culture. In additional experiments, captopril and enalaprilat significantly decreased thymidine incorporation into DNA in these cells. The administration of angiotensin II in the presence of captopril partially offset these suppressive effects.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1991

Immunocytochemical localization of chloramphenicol acetyltransferase as a single-cell marker of transfected and transgenic cells.

A technique is described for immunocytochemical localization of the bacterial gene product chloramphenicol acetyltransferase, which is a commonly used reporter gene in transfected and transgenic cells. The described procedure is capable of localizing the enzyme in individual cells, providing a means of determining the cell type(s) expressing a foreign construct in complex cultures or in tissue sections of transgenic mice.

Animals↗
PubMed1990

Development of software for pulse oximeter and investigation of its realtime response in clinical environment.

We developed a pulse oximeter software at Thorax Centre, Erasmus University as a joint project with an industry and evaluated it in the clinical environment of thorax anaesthesia using a computerized protocol for realtime data collection during routine clinical procedures. This paper gives an account of the results we obtained from the development project and the clinical study. The paper consists of two parts. First part describes different components of the software module and their influence on different aspects of the clinical behaviour of the oximeter. The second part describes the results of realtime response investigation. The investigation was carried out using a personal computer to collect the data continuously during anaesthesia, surgery and post-operative periods. Two other industry standard oximeters, Nellcor and Ohmeda were also included in our study. We collected data on more than fifty patients on an average of eight hours per patient over a period of four months with major emphasis on low-saturation occurrences. The interpretation of the data was focused more on the realtime response anomalies on random cases than on ensemble statistical data evaluation. We found, that there are few factors in clinical environment which often influences the measurement of a pulse oximeter very strongly. Most often the anomalies were found during low saturation measurement. The main objective of this paper is to make the results available to practising clinicians so that it may be useful to identify these occurrences during routine clinical usage.

Evaluation Studies as Topic↗
PubMed1990

Breath detection algorithm in digital computers.

An algorithm for the detection and delineation of breaths is described. The proposed algorithm takes into account the different, common modes of ventilation like the pressure controlled, volume controlled and patient triggered modes of ventilation. Airway flow curve is used as the basic delineator and the airway pressure and the Co2 concentration curves are used to confirm the delineation. A flow chart is also included to explain the algorithm. The detailed explanation and modifications, for additional confirmation and for the selections of constants, to check for the rise or fall of the pressure and Co2 curves, are also included.

Algorithms↗
PubMed1990

Measurement of arterial pressure after cardiopulmonary bypass with long radial artery catheters.

Radial arterial pressure can significantly underestimate central aortic pressure in the postcardiopulmonary bypass (post-CPB) period. At the study institution, routine monitoring of perioperative arterial pressure in adult patients undergoing cardiac surgery is performed with a long radial artery catheter with the distal end positioned in the subclavian artery. In 68 patients presenting for elective cardiac surgery, both a conventional short radial artery catheter and a contralateral long radial artery catheter were placed. Analysis of radial and subclavian arterial pressures post-CPB in the first 47 patients showed average maximum differences of 7 mm Hg systolic and 4 mm Hg mean. In 15% of patients, the differences were clinically significant (greater than 20 mm Hg systolic and/or greater than 14 mm Hg mean). In 28 patients, central aortic pressure was measured post-CPB, and subclavian artery pressure was found to be an excellent estimator of central aortic pressure. There were no significant complications related to using long radial artery catheters in the 68 patients who were followed prospectively. Monitoring subclavian arterial pressure by percutaneous insertion of a long radial artery catheter provides a reliable estimation of central aortic pressure, even in patients with significant radial artery-to-central aortic pressure gradients post-CPB.

Adult↗
PubMed1990

Morphine-induced transactivation of HIV-1 LTR in human neuroblastoma cells.

Infection by human immunodeficiency virus (HIV) is followed in many cases by a clinically quiescent or latent phase that appears to continue as long as host antiviral defense is intact. This has raised the possibility that certain host susceptibility factors (i.e., environmental cofactors) might influence the progression of the disease. In this study we demonstrate that morphine can function to activate HIV/LTR-CAT fusion gene (HIV-long terminal repeat-chloramphenicol acetyltransferase) when transfected into undifferentiated human SH-SY5Y neuroblastoma cells. The stimulatory effect of morphine is amplified in SH-SY5Y cells that have been induced to differentiate first with phorbol 12-myristate 13-acetate (PMA) and is much less in cells differentiated with retinoic acid (RA). Morphine does not appreciably activate HIV/LTR-CAT expression in human MOLT-3 and other T cells. Morphine activation of HIV/LTR-CAT in the SH-SY5Y cells is not reversible by naltrexone and appears to involve a Fos/Jun signaling system. Our results suggest that narcotics such as morphine may lead to activation of latent HIV infection. This may be particularly important in tissues, such as brain, which can host latent HIV infection and which is uniquely damaged in patients with acquired immunodeficiency syndrome (AIDS) as evidenced by neuronal degeneration and dementia. We also predict that these findings may have important implications for the pathogenesis of AIDS, particularly in opiate drug abusers.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Immediate hypersensitivity to Parthenium hysterophorus. I. Association of HLA antigens and Parthenium rhinitis.

Lymphocytes collected from rhinitis subjects with strong positive skin reactions to the pollen allergens of Parthenium hysterophorus (American feverfew) having moderate to high titres of Parthenium-specific serum IgE were analysed for association of HLA-antigens covering 13 specificities of HLA-A, 17 specificities of HLA-B and eight specificities of HLA-DR loci by the NIH two-stage microlymphocytotoxicity assay. Comparison of the phenotypic frequencies of HLA-A and B antigens between Parthenium rhinitis subjects (n = 22) and control subjects (n = 137) did not suggest any significant association when tested for these antigen specificities. A significant correlation in the association of HLA-DR3 antigen with a relative risk of 11.33, however, was observed in Parthenium rhinitis subjects (n = 30) when compared to controls (n = 50).

Cross Reactions↗