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Biomedical subjects

N Saxena

Publications and source records attributed to N Saxena.

At least 37 records · Page 2Linked to original sources
PubMed1999

5-HT(2A/2C) receptor antagonists in the paraventricular nucleus attenuate the action of DOI on NPY-stimulated eating.

Hypothalamic neuropeptide Y (NPY) and serotonin (5-HT)-containing neurons are believed to exert an interactive effect on ingestive behavior. The present study examined the ability of two serotonergic antagonists, spiperone (SPIP), a 5-HT2A antagonist, and mianserin (MIAN), a 5-HT(2A/2C) antagonist, to block the inhibitory action of the 5-HT(2A/2C) receptor agonist 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) on NPY-stimulated eating. Drugs were injected directly into the paraventricular nucleus (PVN), the perifornical (PFH) or the ventromedial hypothalamus (VMH) at the onset of the dark cycle. PVN, PFH and VMH injections of NPY potentiated food intake although only PVN pretreatment with DOI (5-20 nmol) suppressed NPY-induced eating. SPIP or MIAN, injected immediately prior to PVN DOI, reversed the suppressive effect of DOI on NPY feeding. These findings are consistent with other recent data showing that 5-HT2A receptors within the PVN modulate NPY's effect on food intake at the start of the nocturnal period.

Amphetamines↗
PubMed1999

Current status of cardiac anaesthesia.

Cardiac anaesthesia continues to advance at a rapid pace. Many innovations in monitoring and pharmacology have wide application in patients with cardiac disease. In recent years many new cardiac procedures have been introduced to improve results and reduce cost. Anaesthesia for these procedures (e.g., mid-cab, port-access) requires special training and experience so as to reduce morbidity and mortality. Recently short acting anaesthetic agents are used to permit early extubation as a part of fast tracking. Constant vigilance and monitoring are necessary to handle potentially dangerous situations and avoid complications.

Anesthesia↗
PubMed1999

A comparison of esmolol & diltiazem for heart rate control during coronary revascularisation on beating heart.

This prospective study was done to compare the control of heart rate and haemodynamics during coronary artery revascularisation without cardiopulmonary bypass using either esmolol or diltiazem. Sixty adult patients with one or two vessel coronary artery disease, were randomly divided into 2 equal groups. Group A received a 500 micrograms/kg loading dose of esmolol followed by a 100 micrograms/kg/h infusion, for control of heart rate during surgical anastomosis of the coronary vessel. While Group B received 0.15 mg/kg diltiazem as a loading dose followed by a 5 mg/h infusion for heart rate control, during the anastomosis. It was seen that heart rate control was better in Group A, 51.4 (+/- 1.3) beats/min, than in Group B, 69.6 (+/- 3.9) beats/min but the decrease in heart rate was significant in both the groups at peak effect compared to respective predrug values. Group A patients had unchanged systemic resistance and pulmonary artery wedge pressure but mean pulmonary artery pressure and pulmonary vascular resistance were significantly raised. Group B patients had decreased systemic resistance, mean pulmonary artery pressure and pulmonary artery wedge pressure, and reduced right ventricular stroke work index. We concluded that although esmolol provided dramatically slower heart rates, during surgery, the resulting elevations in mean pulmonary artery pressure and pulmonary vascular resistance would require caution if used in patients with underlying right ventricular dysfunction from ischaemia or infarction. Diltiazem by virtue of its effects on systemic vascular resistance, cardiac output, and lowering of mean arterial pressure may be a better choice in hypertensive patients.

Adrenergic beta-Antagonists↗
PubMed1998

Effect of trifluoperazine on in vitro ATP synthesis by Mycobacterium leprae.

The effect of trifluoperazine (TFP), a calmodulin antagonist, was investigated on in vitro ATP levels of human derived Mycobacterium leprae. M. leprae were obtained from biopsies from multi-bacillary forms of leprosy and were incubated in a modified Dubos medium system which supports limited in vitro synthesis of M. leprae. This incubation was carried out in the absence and presence of different concentrations of trifluoperazine. Samples for estimation of bacillary ATP levels were taken at day 0 and at 14 days of incubation. TFP inhibited ATP levels in M. leprae and this inhibitory effect was marginal at 2.5 microg ml(-1) (35% inhibition), highly significant at 5 microg ml(-1) (87% inhibition) and almost total at 10 microg ml(-1) (98.5% inhibition). This compound appears to have potential as an anti-leprotic drug and also as a broad spectrum anti-mycobacterial agent in view of its anti-tubercular activity reported earlier.

Adenosine Triphosphate↗
PubMed1997

Microdensitometric scanning procedure for quantitative assessment of hybridization of rRNA targeting probes in leprosy.

In order to develop an objective criteria of grading of positivity of hybridization signals of gene probes targeting rRNA, a microdensitometric scanning procedure was standardised. Ribosomal RNA was extracted from the bacilli harvested from biopsies of leprosy cases across the spectrum and blotted on nitro-cellulose membranes. M. leprae specific rRNA targeting oligonucleotide probes were end-labelled and hybridization was done by the technique standardised and published earlier. The autoradiographs were developed and microdensitometric scanning was done by altering different parameters. Positivity was graded in 5 grades and compared with visual positivity. Microdensitometric scanning procedure and 5 grade system appear to be useful and reproducible. Signals in paucibacillary specimens were in 2+ to 3+ grading range whereas those in multibacillary specimens varied in grades from 2+ to 5+. This approach appears to have potential usefulness for assessing the bacillary load (possibly viable) in the clinical specimens from leprosy cases.

Autoradiography↗
PubMed1997

Pineal and 5-methoxyindoles in the regulation of seasonal testicular cycle in Indian palm squirrel, Funambulus pennanti.

Effects of late afternoon injections of different doses of melatonin (aMT) and 5-methoxytryptamine (MT) were studied on the testes in sham operated (SO) and pinealectomized (Px) F. pennanti during various reproductive phases. 5-methoxyindoles (MI) in doses 10 and 50 micrograms given for 60 continuous days reduced the weight and activity of the testes in SO and Px animals during the active and regressive phases. During the inactive phase MI administration caused an inhibitory influence on the testes of Px animals. However, during the recrudescence phase no significant effect of MI injections was visible. Both aMT and MT injected for 20 and 40 days respectively failed to influence the testes significantly. Also 1 microgram of the MI had no effect. The results suggest a reproductive phase dependent effect of aMT and MT on the testes of this tropical rodent. The dose and duration of administration are critical and their effects are independent of the pineal gland.

5-Methoxytryptamine↗
PubMed1996

Detection of M. leprae by gene amplification; combined ethidium-bromide staining and probe hybridization.

Biopsy and skin-scraping specimens from 130 leprosy cases across the disease spectrum (56 TT/BT/I, 73 BB/BL/LL, and 1 neuritic case) and 50 healthy contacts were studied to assess the application of gene amplification. The nucleic acids from these clinical specimens were extracted by an integrated freeze-thawing--optimized lysozyme-/proteinase-k treatment-purification and fractionation procedure. The nucleic acids from cultured organisms were isolated by the stepwise procedure earlier standardized at this laboratory. Gene amplification for a 360-bp fragment of the 18-kDa protein gene was carried out using primer and the procedure described by its developers, and a 360-bp fragment on Southern blot was taken as the yardstick of positivity. The polymerase chain reaction product was analyzed by electrophoresis, ethidium-bromide (EB) staining, and blot (B) hybridization. Overall sensitivity ranged from 71% in specimens with undetectable acid-fast organisms to 100% in specimens with demonstrable acid-fast bacilli. A positivity of 73% in TT/BT/I specimens and 93% in BB/BL/LL specimens was observed. Four combinations were discerned: EB+, B+ (71%); EB-suspicious, B+ (14%); EB-, B+ (3%) and EB-, B- (12%). By combining the blot hybridization with EB staining, the sensitivity could be significantly improved as compared to EB staining alone. The test was found to be absolutely specific by the absence of any false positivity in control specimens as well as with purified DNAs from mycobacterial as well as non-mycobacterial organisms, grown from these specimens. It is recommended that for optimum sensitivity and specificity both EB staining and blot hybridization should be done.

Biopsy↗
PubMed1996

Assessment of iodine deficiency disorders using the 30 cluster approach in the National Capital Territory of Delhi.

OBJECTIVE: Iodine Deficiency Disorders (IDD) are a major public health problem in India. The National Capital Territory (NCT) of Delhi is a known iodine deficiency endemic area. The Delhi Government banned the sale of non-iodised salt since 1989. The present study was conducted to assess the status of IDD after 7 years of salt iodisation programme in the state. DESIGN: Cross sectional. METHODOLOGY: The recent indicators recommended by the World Health Organization-United Nations Childrens Fund-International Council for the Control of Iodine Deficiency Disorders (WHO-UNICEF-ICCIDD) were utilized for the assessment of IDD. A total of 30 clusters were selected using population proportionate to size cluster sampling procedure. In each identified cluster, one primary school was selected using random sampling. A total of 6911 school children in the age group of 8-10 years were included for the study. RESULTS: The total goiter prevalence rate was 8.6% while 2.1, 8.4, 17.6 and 71.9% of the children had urinary iodine excretion levels of < 2, 2-4.9, 5-9.9 and 10 and above mcg/dl, respectively. The median urinary iodine excretion was 17 mcg/dl. Of the 1854 salt samples analyzed, salt with a nil iodine content was consumed only by 1.4% of the beneficiaries. Forty one per cent of families consumed salt with an iodine content of less than 15 ppm. CONCLUSION: IDD continues to be a public-health problem in the NCT of Delhi. There is a need of strengthening the existing monitoring system for the quality of iodised salt.

Child↗
PubMed1993

Topical nitroglycerin prevents the pressor response to tracheal intubation and sternotomy in patients undergoing coronary artery bypass graft surgery.

Thirty adult patients who underwent coronary artery bypass graft surgery were allocated randomly to one of two equal groups to receive either 2% nitroglycerin, or a placebo ointment, applied topically over an area of 5 cm by 10 cm, in a double-blind manner, 1 h before induction of anaesthesia. Premedication consisted of oral diazepam 5-10 mg, intramuscular morphine 0.2 mg.kg-1 and promethazine 0.4 mg.kg-1. Anaesthesia was induced with morphine 0.15-0.2 mg.kg-1 and thiopentone 3-5 mg.kg-1. Laryngoscopy and tracheal intubation were facilitated by suxamethonium 1.5 mg.kg-1, and pancuronium 0.1 mg.kg-1 was used for subsequent muscle relaxation. Anaesthesia was maintained with 0.5% halothane and 40% oxygen in nitrous oxide. A significant increase in blood pressure occurred during and after laryngoscopy and tracheal intubation, and following midline sternotomy in the control group. These changes were absent in patients pretreated with topical nitroglycerin. The nitroglycerin group also maintained a lower rate-pressure product than the control group. We conclude that topical nitroglycerin is a simple and useful pretreatment to prevent the pressor response to tracheal intubation and midline sternotomy in patients undergoing coronary artery bypass graft surgery.

Adult↗
PubMed1993

Hydrolytic enzymes of rhesus placenta during Plasmodium cynomolgi infection: ultrastructural and biochemical studies.

Placenta in monkey demonstrated altered pathophysiology after P cynomolgi infection. The electronmicroscopic observations showed slight complete focal necrosis of the placental tissue, besides alterations in total protein, phosphatases and proteinases. These changes in cellular constituents of placenta during malaria infection may be responsible for malfunctioning of the organ and in turn, abnormal development of foetus.

Animals↗