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Biomedical subjects

O Prakash

Publications and source records attributed to O Prakash.

At least 109 records · Page 6Linked to original sources
PubMed1985

Oxygen consumption and blood gas exchange during controlled and intermittent mandatory ventilation after cardiac surgery.

The purpose of this study was to determine the consequence of intermittent mandatory ventilation (IMV) on gas exchange, cardiac function, and blood oxygenation immediately after cardiopulmonary bypass grafting. The results showed a marked increase in oxygen uptake, cardiac index, and pulmonary artery pressure, and a decrease in mixed venous oxygen saturation of 20 adult patients recovering from surgery. These effects may have been associated with the presence of an endotracheal tube, because 2 h after removal of this tube there were significant decreases in elevated cardiac function and blood oxygenation variables, while mixed venous oxygen saturation increased from 64% to 75% (p less than .001). These results suggest that IMV can dramatically increase oxygen uptake, cardiac index, and pulmonary artery pressure in awake and intubated patients.

Adult↗
PubMed1985

Reaginic allergy to Parthenium pollen: evaluation by skin test and RAST.

The pollen of Parthenium hysterophorus, an alien weed growing wild in India was found to be a potential source of allergic rhinitis. A clinical survey showed that 34% of the patients suffering from rhinitis and 12% suffering from bronchial asthma gave positive skin-prick test reactions to Parthenium pollen antigen extracts. Parthenium-specific IgE was detected in the sera of sixteen out of twenty-four patients suffering from seasonal rhinitis. There was 66% correlation between skin test and RAST.

Asthma↗
PubMed1985

Molecular cloning, characterization, and genetic mapping of an endogenous murine mammary tumor virus proviral unit I of C3H/He mice.

We have cloned and characterized a novel endogenous murine mammary tumor virus proviral unit of the C3H/He strain of mice. The cloned proviral unit is 16 kilobase pairs (kbp) in size and is composed of a 5.6-kbp 5' EcoRI segment of an endogenous provirus with 10.4-kbp flanking cellular sequences. A comparison of the restriction map of the cloned proviral DNA with that of an endogenous provirus of the GR strain of mice has revealed minor differences in restriction sites on the two proviruses. The restriction enzyme SstI, which does not cleave the 5' EcoRI fragment of GR DNA, cleaves the C3H/He proviral sequences once; MspI has an additional site in the C3H/He proviral sequences. By using a subcloned fragment containing unique cellular sequences as a hybridization probe, we (i) mapped the C3H/He proviral unit to chromosome 14 by using mouse-hamster somatic cell hybrids, and (ii) demonstrated that this proviral unit is also present in the genome of DBA/2 mice. From these results we conclude that the C3H/He strain of mice acquired this proviral unit from DBA stock by genetic transmission. Our data also indicate that the murine mammary tumor virus sequences present in the gag-specific proviral unit of C3H/He mice extend at least 2.45 kbp downstream of the EcoRI site in the genomic DNA. Since the structural organization and chromosomal location of this proviral unit are distinct from those of previously reported proviral units represented by similar-sized (16.7-kbp) EcoRI fragments, we tentatively propose to designate this proviral unit Mtv-7a.

Animals↗
PubMed1985

Cardiopulmonary response to inspiratory pressure support during spontaneous ventilation vs conventional ventilation.

Twenty-six patients undergoing coronary bypass graft surgery were randomized in two groups. In group 1, 14 patients were subjected to inspiratory pressure support during spontaneous ventilation (IPSSV) and 12 patients in group 2 were treated with conventional ventilation (CV). The outcome of IPSSV was a definite advantage over the conventional ventilation. The patients in IPSSV group needed +/- 3 h of pressure support before tracheal extubation. The other patients in CV group 2 needed +/- 6 h of mechanical ventilation before being weaned off the ventilator.

Adult↗
PubMed1985

Prevalence of occupational asthma in silk filatures.

A clinical survey in two silk filatures revealed that 36.2% of the persons engaged in the processing of natural silk were suffering from bronchial asthma, while 16.9% of the total subjects had asthma of occupational origin. Skin prick tests using crude silkworm cocoon and pupal allergen extracts revealed that 28.8% of the subjects were sensitive to the silkworm-derived allergens. IgE antibodies specific to both cocoon and pupal allergens were demonstrable by RAST in the sera of patients with positive skin reactions and occupational asthma.

Antibody Specificity↗
PubMed1984

A microcomputer based charting system for documentation of circulatory, respiratory and pharmacological data during anesthesia.

A system for the on-line production of anaesthetic records with a microcomputer is described. The requirements of the system are a keyboard, a video display unit and a colour plotter. The system requires no programming expertise from anaesthetists and nurses. The records have improved information display, patient care and reduced time spent in administration effort. Disadvantages are the relatively high cost and requirement of preprocessing of haemodynamic and respiratory parameters.

Anesthesiology↗
PubMed1984

High resolution chromosomes of the t(9;22) positive leukemias.

A combined bromodeoxyuridine (BrdU) and actinomycin D (AMD) treatment of methotrexate (MTX) synchronized bone marrow cells from four patients with chronic myelogenous leukemia (CML), and two each with acute lymphocytic (ALL) and acute nonlymphocytic (ANLL) leukemia were used to define the breakpoints involved in the t(9;22) found in subgroups of these three disorders. An additional 20 patients with CML were studied with the MTX technique alone. All cases showed the same breakpoints at subbands 9q34.1 and 22q11.2. In CML, it was possible to further define the breakpoint of chromosome 22 to subband q11.21.

Acute Disease↗
PubMed1984

Proteins encoded by the long terminal repeat region of mouse mammary tumor virus: identification by hybrid-selected translation.

The long terminal repeat (LTR) region of mouse mammary tumor virus (MMTV) is known to contain an open reading frame of sufficient length to code for a protein of 36,000 Mr. The coding capacity of the 3' sequences of MMTV genomic RNA has been demonstrated by in vitro translation studies, which have reported the synthesis of four related proteins: p36, p24, p21, and p18. These proteins are overlapping translation products of the same open reading frame, with the smaller ones initiating at internal methionine codons. From the predicted amino acid sequence of the LTR protein, we have selected a region likely to be antigenic, obtained a synthetic peptide of that region, and raised antiserum to the peptide. The antipeptide serum specifically immunoprecipitated all four proteins from in vitro translated genomic 3' MMTV RNA, plus an additional one of 32,000 Mr. Published sequence data of MMRV LTRs show an internal AUG codon at a position which could initiate a protein of 32,000 Mr. The three smaller in vitro translation products (p24, p21, and p18) were consistently synthesized in much greater amounts than the p36 or p32 protein. The relative amount of each in vitro synthesized protein from genomic MMTV RNA could be predicted and was in good agreement with the postulated effect of flanking nucleotides on the efficiency of the respective AUG initiation codon. Polyadenylated RNAs, isolated from various mouse tissues, were selected by hybridization to plasmid DNA containing MMTV LTR sequences immobilized on nitrocellulose. In vitro translation of hybrid-selected mRNAs isolated from BALB/c mouse lactating mammary glands and carcinogen-induced mammary tumors, followed by immunoprecipitation with antipeptide serum, revealed that only one polypeptide was synthesized by the MMTV LTR-specific mRNA, the 36,000 Mr species.

Animals↗
PubMed1984

A study on the influence of ketamine on systemic and regional haemodynamics in conscious rabbits.

Effects of ketamine hydrochloride (2, 6 and 18 mg X kg-1, i.v.) were investigated on systemic and regional haemodynamics using a radioactive microsphere method in conscious rabbits. Ketamine decreased respiratory frequency in a dose-dependent manner for up to 5 min. A significant fall in the mean arterial blood pressure (with the two highest doses), together with a short lasting tachycardia, was observed with ketamine. The cardiac output and blood flow to many tissues were not changed by this anaesthetic agent. However, increased blood flow was noticed in discrete regions of the brain (cerebral hemispheres) and heart (left ventricular endocardium). Vasodilation in the cerebral hemispheres with this agent producing dissociative anaesthesia is in contrast to the generally observed decrease in cerebral blood flow with other anaesthetic agents.

Animals↗
PubMed1983

Cyclic AMP induces synthesis of prostaglandin E1 in platelets.

Although platelets are known to synthesize small amounts of prostaglandin E1 the control of the formation of this prostanoid has not been investigated. Incubation of human platelet-rich plasma with various compounds which are known to increase cyclic AMP concentration in platelets and inhibit platelet aggregation also increased intracellular prostaglandin E1 synthesis. The prostaglandin E1 was isolated by high pressure liquid chromatography and definitively identified by negative and positive ionization mass spectroscopy. The amounts of prostaglandin E1 formed were proportional to the concentration of cyclic AMP in platelets. Prostacyclin (10 nM) which is the most potent stimulator of cyclic AMP formation increased intracellular cyclic AMP by 4.6 fold and prostaglandin E1 level by 3 fold over the basal levels. Addition of theophylline, a cyclic AMP phosphodiesterase inhibitor, together with prostacyclin increased cyclic AMP concentration 8.7-fold and prostaglandin E1 level 12-fold compared to basal concentrations. Dibutyryl cyclic AMP (2 mM) and 8-bromo cyclic AMP (0.1 mM) increased prostaglandin E1 levels by 3 fold and 2 fold over the basal level, respectively. Prostaglandin D2 (3 microM) when added to platelet-rich plasma increased the cyclic nucleotide levels by 2 fold concomitant with 2 fold increase in prostaglandin E1 concentration. In contrast prostaglandin E2 or prostaglandin F2 alpha which had no effect on cyclic AMP level did not affect the prostaglandin E1 synthesis. Addition of 2',5'-dideoxyadenosine, an inhibitor of adenylate cyclase, to platelet-rich plasma inhibited both the increase of intracellular prostaglandin E1 and cyclic AMP levels induced by prostacyclin.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1983

Evidence for a prokaryotic promoter in the murine mammary tumor virus long terminal repeat.

The long terminal repeat (LTR) of C3H murine mammary tumor virus (MuMTV) is approx. 1.3 kb long. HaeIII digestion of a cloned PstI fragment containing the left-end LTR generated four fragments of sizes 0.56, 0.41, 0.34 and 0.14 kb, one of which (0.41 kb) had a promoter activity in Escherichia coli. This was demonstrated by replacing the bacterial promoter for the neomycin-resistance (NmR) gene in the plasmid pKC56 with the HaeIII fragments. Only the 0.41-kb fragment that contains sequences from the U3 region of the LTR was found to contain a promoter, as shown by the expression of the drug-resistance phenotype in the recombinant plasmid. The strength of this promoter was comparable to or greater than that found with the parental NmR gene promoter. S1 nuclease mapping of the NmR gene transcript indicated that the initiation of this transcript occurred within the 0.41-kb LTR fragment from a site approx. 10 bp upstream from the 3' end. A comparison of the known DNA sequences in the MuMTV LTR with those found in bacterial promoters revealed that a 'Pribnow box', the initiation signal for the prokaryotic promoters, is present in the 0.41-kb LTR fragment upstream from the initiation site. Furthermore, in a recombinant plasmid that contained the complete LTR the same promoter sequences appeared to be involved in the initiation of RNA transcription. The 0.34-kb LTR fragment, which contains sequences derived from the U3 and U5 regions of the LTR, did not possess promoter activity in E. coli. However, it was found to induce deletions of adjacent plasmid DNA sequences. The deletions were specifically initiated from the downstream end of the LTR-fragment insert. The presence of a prokaryotic promoter in the MuMTV LTR, together with the observation that certain LTR sequences can induce deletions, analogous to those caused by transposable elements, in recombinant plasmids suggest that the MuMTV LTR may have evolved from such elements.

Base Sequence↗
PubMed1983

A comparison of systemic and regional hemodynamic effects of d-tubocurarine, pancuronium, and vecuronium.

This study was designed to compare the effects of three neuromuscular blocking agents, in a clinically relevant dose range, on the regional distribution of blood flow measured with 15-microns radioactive microspheres in anesthetized, optimally ventilated cats. d-Tubocurarine (400, 800, and 1,600 micrograms X kg-1) caused hypotension and a decrease in ascending aortic blood flow. Pancuronium (20, 40, and 80 micrograms X kg-1) only caused a moderate tachycardia, while vecuronium (40, 80, and 160 micrograms X kg-1) was devoid of any systemic hemodynamic effect. Neither pancuronium nor vecuronium caused major changes in regional blood flows. On the other hand, d-tubocurarine increased blood flow to the stomach but decreased that to the kidneys, liver, skin, spleen, intestine, and adrenal glands. These effects of d-tubocurarine show a striking resemblance to those elicited by the infusion of histamine. Blood flow to the nerve-stimulated tibialis anterior muscle, which was about six times that of the unstimulated muscle, was decreased significantly by all three neuromuscular blockers. In conclusion, the results clearly show that, while d-tubocurarine produces major cardiovascular disturbances, pancuronium and, in particular, vecuronium do not cause serious changes in systemic and regional hemodynamics in doses that are two to four times the ED90 for neuromuscular blocking action.

Animals↗
PubMed1982

Purification and properties of the biotin repressor. A bifunctional protein.

Definitive evidence is presented for the bifunctional nature of the biotin repressor protein which possesses both regulatory and enzymatic activities. The repressor protein can activate biotin in the presence of ATP to form biotinyl-5'-adenylate, the co-repressor which remains tightly bound to the repressor protein. This complex can either bind to the operator site and inhibit transcription or transfer the biotinyl moiety to a lysine residue of the apoenzyme of acetyl-CoA carboxylase. The two activities were coincident throughout a purification procedure which resulted in a 3500-fold increase in activity. Gel electrophoresis of the purified preparation, under native or denaturing conditions, showed three proteins with the activity corresponding to the major protein band of apparent Mr = 34,000. On gel exclusion chromatography, the activity was also associated with a protein of Mr varying fro 37,000-44,000, indicating the protein is monomeric. The occasional appearance of multiple bands with biological activity in the native gels suggests that the repressor protein can also exist in multimeric forms. On chromatofocusing, the repressor activity and the holoenzyme synthetase activity were coincidental, with the peak of activity at pH 7.2, the isoelectric point. Only a single protein band with Mr = 34,000 was observed on SDS gel electrophoresis of all fractions showing activity.

Acetyl-CoA Carboxylase↗
PubMed1982

The origin of man: a chromosomal pictorial legacy.

Man, gorilla, and chimpanzee likely shared an ancestor in whom the fine genetic organization of chromosomes was similar to that of present man. A comparative analysis of high-resolution chromosomes from orangutan, gorilla, chimpanzee, and man suggests that 18 or 23 pairs of chromosomes of modern man are virtually identical to those of our "common hominoid ancestor", with the remaining pairs slightly different. From this lineage, gorilla separated fist, and three major chromosomal rearrangements presumably occurred in a progenitor of chimpanzee and man before the final divergence of these tow species. A precursor of the hominoid ancestor and orangutan is also assumed.

Animals↗
PubMed1982

Computer-based patient monitoring.

A computerized ICU patient monitoring system is described. The bedside module is a general-purpose unit designed to replace the entire range of traditional monitoring devices. All user-interaction, signal processing, and data presentation in this unit are under the direct control of a microcomputer. The nurse-station module, also containing a microcomputer, is responsible for information routing, controlling nurse-desk equipment as well as data and signal presentation. The system hs been in use since 1978 in our 8-bed surgical ICU and since 1980 in an 8-bed coronary care unit. The application programs for ECG, blood pressures, temperature, thermodilution cardiac output, and fluid balance are discussed. The programs for monitoring controlled ventilation are presented in detail. The possibility for feedback control of mechanical ventilation is reviewed. Examples of clinical advantages from automation are given.

Blood Pressure↗