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Biomedical subjects

A Tripathi

Publications and source records attributed to A Tripathi.

At least 55 records · Page 3Linked to original sources
PubMed1995

Effect of preoperative oral fluids on gastric volume and pH in postpartum patients.

The effect of preoperative oral fluids to postpartum patients on the gastric volume and pH was compared with normally fasting postpartum and non-pregnant patients undergoing sterilisation. Forty consecutive postpartum patients and twenty non-pregnant patients scheduled for sterilisation procedure were selected for the study. All patients were fasted overnight. Twenty postpartum patients were randomly allocated to receive 150 ml of plain water two and half hours before surgery (Group 1), while the remaining postpartum patients (Group 2) and non-pregnant patients (Group 3) continued their overnight fast as usual. After induction of anesthesia, gastric volume and pH was measured in all the patients. The mean gastric volume was found to be 21.9 +/- 8.49 ml in Group 1, 22.55 +/- 8.30 ml in Group 2 and 22.65 +/- 8.17 ml in Group 3. The mean pH was found to be 2.21 +/- 0.98 in Group 1, 2.18 +/- 0.88 in Group 2 and 2.12 +/- 1.02 in Group 3. The difference in the volume and pH in all the three groups was statistically insignificant. The difference in the incidence of patients with combined high risk factors of acid aspiration syndrome (gastric fluid volume > 25 ml and pH < 2.5) among the three groups was also insignificant. The authors conclude that ingestion of 150 ml of plain water approximately two and half hours before scheduled time of surgery in overnight fasted postpartum patients does not increase the risk of aspiration syndrome.

Adult↗
PubMed1992

Foliar injury and leaf diffusive resistance of rice and white bean in response to SO2 and O3, singly and in combination.

Plants of rice (Oryza sativa) and white bean (Phaseolus vulgaris) were exposed to 524 microg m(-3) SO2, 392 microg m(-3) O3 and a mixture of both gases, i.e. 524 microg m(-3) SO2 and 392 microg m(-3) O3 to determine the visible foliar injury and leaf diffusive resistance. Response of leaf diffusive resistance was measured on upper and lower surfaces of leaves, i.e. the two unifoliate leaves of bean and the first, second and third primary leaves of rice. The difference in the response may be due to sensitive guard cells causing stomatal closure in the presence of O3, whilst a low concentration of SO2 caused the stomata to open. Thus, SO2 alone is known to decrease, and O3 tends to increase leaf diffusive resistance. However, exposure to both gases increases or decreases the resistance, depending on the species response.

Journal Article↗
PubMed1991

Impact of mass bathing on the water quality of the Ganga River at Haudeshwarnath (Pratapgarh), India--a case study.

This paper reports on the impact of mass bathing on Ganga River water quality on the occasion of the Maha-Shivaratri festival at Haudeshwarnath Ghat situated on the left bank of the River Ganga in the district of Pratapgarh, India. Water samples collected from three sampling points before and after mass bathing were analysed for a total of 17 physico-chemical and seven biological parameters. It was concluded from the results that mass bathing causes a significant change in water quality of the river, which may represent a health hazard to users of the river water.

Baths↗
PubMed1990

Cutaneous vascular reflexes during exercise in the heat.

Eight relatively fit men performed cycle ergometer exercise (50% VO2max) for 30 min at 35 degrees C, less than 40% rh. To determine the importance of changes in cardiac filling pressure on the cutaneous vascular responses during exercise, we compared data from eight control (normovolemic) and four hypovolemic (19.5% decrease in plasma volume (PV) induced by diuretics) experiments. Cardiac output was maintained at 13.9 +/- 0.8 l.min-1 during steady state exercise in the two conditions. However, heart rate was higher (P less than 0.05) and stroke volume (SV) was slightly, although not statistically lower during hypovolemic exercise. Forearm venous compliance (FVC) was significantly lower during hypovolemic exercise than during control exercise (P less than 0.05). The increases in forearm blood flow and arterial blood pressure during exercise were not affected significantly by hypovolemia. FVC and SV in both conditions were linearly related to changes in central venous pressure during exercise (r2 = 0.88 and 0.78, respectively). Since changes in arterial pressure during exercise were not correlated with the observed arteriomotor and venomotor responses, we concluded that low pressure baroreceptors may have induced peripheral vascular reflexes, which act to maintain cardiac output during exercise in the heat.

Adult↗
PubMed1990

Relation of salivary phosphorus and alkaline phosphatase to the incidence of dental caries in children.

The phosphorus concentration and alkaline phosphatase activity in saliva may be related to the susceptibility to dental caries and supragingival calculus. Hence, the unstimulated mixed saliva of child patients were assayed by biochemical methods to determine the phosphorus concentration and alkaline phosphatase activity in such salivary samples. It is very interesting to note that higher phosphorus concentration and alkaline phosphatase activity were found in patients with rampant caries as compared to that with non rampant/control group.

Adolescent↗
PubMed1989

Peripheral vascular reflexes elicited during lower body negative pressure.

To study the interaction between thermal reflexes and baroreflexes on human forearm vasomotor and venomotor control, and to test the hypothesis that peripheral veins are responsive to baroreceptor unloading during gravitational stress, we imposed lower body negative pressure (LBNP) between 10 and 50 mm Hg (Torr) at ambient temperatures (Ta) of 28 and 37 degrees C. We measured arterial and central venous pressures (CVP), heart rate, forearm venous volume, forearm venous pressure, and forearm blood flow in 12 volunteers. Decreases in CVP were relatively large at 10 mm Hg LBNP (p less than 0.01) at both Ta, and less thereafter. Arterial systolic and pulse pressures were not significantly reduced until LBNP exceeded 30 mm Hg (p less than 0.05). With LBNP up to 20 mm Hg, moderate decreases in forearm venous compliance and increases in forearm vascular resistance occurred. Between 30 and 50 mm Hg LBNP, the changes in both compliance and resistance per unit change in CVP were more than tripled. We concluded that unloading of cardiopulmonary mechanoreceptors stimulates increases in both forearm vasomotor and venomotor tone and that addition of arterial baroreceptor unloading adds to these reflex responses.

Adult↗
PubMed1987

Diminished baroreflex control of forearm vascular resistance in physically fit humans.

The stimulus-response characteristics of cardiopulmonary baroreflex control of forearm vascular resistance (FVR) were studied in five unfit [UF, maximal O2 consumption (VO2 max) = 38.5 ml X min-1 X kg-1] and six fit (F, VO2 max = 57.0 ml X min-1 X kg-1) subjects. We assessed the relationship between reflex stimulus, i.e., changes in central venous pressure (CVP) and response, i.e., FVR, during selective unloading of the cardiopulmonary mechanoreceptors with lower body negative pressure (0 to -20 mmHg). The linear relationship between FVR and CVP, the gain of this baroreflex, was significantly diminished in the F subjects, -2.42 +/- 0.57 U/mmHg, compared with the UF, -5.15 +/- 0.58 U/mmHg. Both groups, F and UF, had similar resting values for CVP and FVR; thus the diminished gain in F subjects was not simply an artifact resulting from a shift of the set point along the baroreflex stimulus-response curve. We also found a linear relationship between baroreflex gain and total blood volume (r = 0.59, P less than 0.05). We conclude that the gain of this vascular reflex is attenuated in trained individuals and is related to cardiovascular adaptations, such as an increased blood volume, associated with exercise training.

Blood Pressure↗
PubMed1986

Influence of alveolar hypoxia on pulmonary vasomotor responses to almitrine in the dog.

Almitrine bismesylate (5-10 micrograms/kg) was given as an intravenous bolus to anaesthetized, paralysed dogs with closed-chest (n = 5) and with open-chest (n = 7) in whom the retrocardiac lobe was separately ventilated. Pulmonary, lobar and systemic haemodynamics were measured under hypoxic, normoxic and hyperoxic conditions. Total pulmonary blood flow was measured by thermodilution and lobar flow by electromagnetic flow meter. In the closed-chest preparations, almitrine caused an increase in pulmonary vascular resistance (PVR) at all levels of inspired oxygen, the increments being 82% (30% O2), 91% (air) and 9% (13% O2). The control PVR varied inversely with arterial PO2 but there was no significant interaction between the almitrine and hypoxia induced vasoconstriction with multiple linear regression analysis. In the open-chest preparations, PVR and lobar vascular resistance (LVR) increased after almitrine by 48% and 41% respectively when both lung and lobe inspired 30% O2. When the lobe was switched to 12.5% O2 or nitrogen (lung inspiring 30%) PVR again increased (+52%) after almitrine but LVR decreased in five of seven lobes (lobar flow increasing despite constant cardiac output), the overall change being -4%. Analysis of covariance showed that the lobar response to almitrine was significantly different under hypoxic conditions compared with hyperoxic (P less than 0.05). With ventilation maintained constant, there was no significant change in arterial PO2 after almitrine in any experimental condition. In conclusion, almitrine is generally a pulmonary vasoconstrictor but can dilate vessels when they are constricted by local hypoxia. Almitrine does not enhance local hypoxic vasoconstriction in the dog.

Almitrine↗
PubMed1986

Forearm skin and muscle vasoconstriction during lower body negative pressure.

In view of conflicting reports of skeletal muscle and skin blood flow participation in baroreceptor-mediated reflexes, we studied the effects of graded lower body negative pressure (LBNP) on cutaneous and muscular components of forearm blood flow (FBF) in seven male subjects at 28 degrees C. FBF was measured by venous occlusion plethysmography and cutaneous flow by laser-Doppler velocimetry, the difference being the muscular flow. Mean FBF decreased by 39 and 56% from control at LBNP of 20 and 50 Torr, respectively. Skin flow decreased linearly with graded LBNP contributing 32% of the decrease of total blood flow at 20 Torr and then 50% of total decrease of blood flow at 50 Torr. Conversely, the decrease in muscle flow represented 68% of the total decrease at LBNP of 20 Torr and then 50% of the total decrease at LBNP of 50 Torr. We concluded that both skin and muscle circulations participate in sustained peripheral vasoconstriction during LBNP, with muscle flow achieving near maximum vasoconstriction by 20 Torr and skin showing a graded vasoconstriction to decreases in LBNP.

Adult↗
PubMed1985

Type B atrial receptor discharge increases on opening a nonhypotensive arteriovenous shunt in the dog.

A vagovagal cardioacceleratory reflex is activated when an arteriovenous (a-v) shunt is opened in the dog. However, the receptors which initiate this reflex have not been localized. Type B atrial receptor excitation was considered to be a major component of this reflex. The effect of opening a femoral nonhypotensive a-v shunt (i.e., shunt open plus infusion of blood to compensate for the resultant fall in mean arterial and pulse pressure) on type B atrial receptor discharge and heart rate was therefore studied in seven anesthetized, artifically ventilated dogs with beta-adrenergic blockade. Right atrial and aortic blood pressures, heart rate, and type B atrial receptor discharge was studied before and after opening a femoral a-v shunt. On opening the a-v shunt there was a significant increase (44%) in the average activity of type B atrial receptors and a small, but significant (6.8%) increase in heart rate. A significant linear positive correlation was observed between the change in activity of type B atrial receptors and the shunt flow. The results suggest that type B atrial receptors may be one of the receptor groups that initiate this vagovagal reflex.

Afferent Pathways↗
PubMed1984

Effect of temperature and baroreceptor stimulation on reflex venomotor responses.

To investigate the interaction of thermal reflexes and baroreflexes in the control of the peripheral veins, we studied in supine humans the effects of lower body negative pressure (LBNP) and neck suction (NS) on forearm veins at ambient temperatures (Ta) of 18, 28, and 37 degrees C. Forearm venous volume (FVV)-venous pressure (FVP) relations (forearm venous capacitance) on six subjects showed an increase from 18 through 28 to 37 degrees C (P less than 0.001). Heart rate increased (P less than 0.001) and forearm venous capacitance decreased (P less than 0.001) in proportion to the level of LBNP applied from 20 to 50 Torr at all Ta. At 50 Torr LBNP, FVV at 30 cmH2O, FVP decreased from control values of 2.5, 3.8, and 4.4 to 1.6, 2.7, and 3.4 ml/100 ml at 18, 28, and 37 degrees C, respectively. We also studied venomotor responses using the occluded limb technique. Although LBNP caused venoconstriction, NS applied either alone or during LBNP produced no change in venomotor tone. Therefore we concluded that carotid baroreceptors play little role in reflex venomotor adjustments. Since changes in mean arterial and pulse pressures during LBNP did not account for the observed venomotor responses, we concluded that low-pressure baroreceptors initiate significant venoconstrictor reflexes over a wide range of Ta.

Adult↗
PubMed1983

Action of almitrine bismesylate on pulmonary vasculature in the dog: preliminary report.

The effects of almitrine bismesylate on the pulmonary circulation have been investigated in anaesthetized dogs, paralysed and artificially ventilated. An i.v. bolus of almitrine bismesylate (10 micrograms X Kg-1) caused a 35% increase in specific pulmonary vascular resistance under normoxic or hyperoxic conditions but only a 2% increase when pulmonary vessels were constricted by hypoxia (13% inspired O2). With local hypoxia, confined to the retrocardiac lobe, almitrine bismesylate caused lobar vasodilation (specific vascular conductance increased by 10%) while at the same time conductance fell by 38% in the rest of the lung which was hyperoxic. The almitrine-induced vasoconstriction was not abolished by alpha- or beta blockade, indomethacin, vagotomy or bilateral clamping of both common carotids in the neck. With constant ventilation, no rise of arterial PO2 occurred following almitrine bismesylate . In the presence of local hypoxia, the drug by virtue of its inhibition of local hypoxic vasoconstriction caused PaO2 to fall slightly. In conclusion, almitrine bismesylate constricts pulmonary vessels in normoxia and dilates them when they are constricted by hypoxia. The mechanism is unknown but it is likely to be an intra-rather than an extrapulmonary site of action.

Almitrine↗
PubMed1982

Closely coupled excitation of gamma-motoneurones by group III Muscle afferents with low mechanical threshold in the cat.

1. The reflex responses of gamma-motoneurones to discharges of muscle receptors innervated by Group III axons have been examined in hind-limb muscles of decerebrated and spinal cats.2. Electrical stimulation of the gastrocnemius medialis nerve at a strength sufficient to excite Group III axons caused excitation of gastrocnemius lateralis or soleus gamma-motoneurones. The excitation was more prominent in the spinal animal.3. Excitation of either silent or tonically firing gamma-motoneurones was a secure, driven type of response consisting of one or two spikes occurring at fairly fixed latency in response to a single stimulus. Eighteen out of thirty-nine gamma-motoneurones studied showed such excitation.4. Subtracting peripheral conduction times of the gamma-motoneurone impulse and the earliest component of the Group III volley from the latency of reflex excitation gave a range of central delays of 1.8-4.8 msec (mean 3.0 msec).5. Inhibitory Group III effects were also seen but were less pronounced than the excitation.6. The origin of the receptors connected to the Group III axons whose discharge causes driven excitation of gamma-motoneurones was investigated.7. Isometric twitch contractions of a muscle caused pronounced facilitation or excitation of homonymous and heteronymous gamma-motoneurones. Excitation occurred close to the peak or during relaxation of the twitch with a range in latency of 30-110 msec. The muscles studied were triceps surae, flexor digitorum and hallucis longus.8. Pressure or light taps applied to the gastrocnemius medialis muscle caused an increase in discharge frequency in twenty out of twenty-eight gamma-motoneurones of the same muscle (four were inhibited). The response to a steady stimulus adapted but could outlast it by many seconds. Pressure was more effective when applied to the proximal or distal parts of the muscle.9. Fifteen out of thirty-eight gastrocnemius medialis receptors having Group III axons (conduction velocities 5-27 m/sec) were found to discharge one, or occasionally two, spikes to twitch contractions of the parent muscle at latencies of 30-80 msec.10. Eight out of ten receptors with Group III axons that responded to contraction had low thresholds to pressure and taps, whereas the majority of the twenty-three Group III units which were insensitive to contraction had high thresholds to such stimuli. Receptive fields of all Group III units were confined to either the proximal third or distal third of gastrocnemius medialis or, in a few instances, the Achilles tendon.11. We conclude that discharges in Group III axons from receptors which respond to non-noxious, low threshold mechanical stimuli cause a tightly coupled excitation of gamma-motoneurones. The likely contribution of this reflex to the control of movement is discussed.

Action Potentials↗
PubMedDate not supplied

Alterations of the P16 gene in uterine cervical carcinoma from Indian patients.

In our analysis, alterations in the P16 tumor suppressor gene were seen in 33% (15/46) of sampled uterine cervical lesions. Among the alterations, mutations in P16 were detected in 15% (7/46) of the samples. One mutation occurred at intron 1/exon 2 splice junction. All the other mutations were in exon 2 with three of them as silent mutations. The promoter hypermethylation and homozygous deletion of P16 gene were detected in 6.5% (3/46) and 8.7% (4/46) of the samples respectively. Loss of heterozygosity and microsatellite size alterations at the P16 locus were seen in 17% (8/46) of the samples. HPV16/18 infection was detected in 76% (35/46) of the samples. But no association was found between P16 alterations and HPV infection. Thus, it seems that P16 inactivation may be associated with the development of some uterine cervical carcinoma.

Adult↗
PubMedDate not supplied

Intraocular pressure -- all that is raised is not glaucoma.

Increased intraocular pressure invariably sets our mind in the direction of either establishing or ruling out the diagnosis of glaucoma and in the process, sometimes, certain hidden factors may escape our attention, leading to some delay in delivering the specific treatment to the patient. We present a case whose underlying pathology remained obscured for more than 10 years before we examined this patient and discovered the hidden secret.

Adult↗