Biomedical subjects

A Wadhwa

Publications and source records attributed to A Wadhwa.

At least 19 recordsLinked to original sources

PubMed2005

Magnesium sulphate only slightly reduces the shivering threshold in humans.

BACKGROUND: Hypothermia may be an effective treatment for stroke or acute myocardial infarction; however, it provokes vigorous shivering, which causes potentially dangerous haemodynamic responses and prevents further hypothermia. Magnesium is an attractive anti-shivering agent because it is used for treatment of postoperative shivering and provides protection against ischaemic injury in animal models. We tested the hypothesis that magnesium reduces the threshold (triggering core temperature) and gain of shivering without substantial sedation or muscle weakness. METHODS: We studied nine healthy male volunteers (18-40 yr) on two randomly assigned treatment days: (1) control and (2) magnesium (80 mg kg(-1) followed by infusion at 2 g h(-1)). Lactated Ringer's solution (4 degrees C) was infused via a central venous catheter over a period of approximately 2 h to decrease tympanic membrane temperature by approximately 1.5 degrees C h(-1). A significant and persistent increase in oxygen consumption identified the threshold. The gain of shivering was determined by the slope of oxygen consumption vs core temperature regression. Sedation was evaluated using a verbal rating score (VRS) from 0 to 10 and bispectral index (BIS) of the EEG. Peripheral muscle strength was evaluated using dynamometry and spirometry. Data were analysed using repeated measures anova; P<0.05 was statistically significant. RESULTS: Magnesium reduced the shivering threshold (36.3 [SD 0.4] degrees C vs 36.6 [0.3] degrees C, P = 0.040). It did not affect the gain of shivering (control, 437 [289] ml min(-1) degrees C(-1); magnesium, 573 [370] ml min(-1) degrees C(-1); P=0.344). The magnesium bolus did not produce significant sedation or appreciably reduce muscle strength. CONCLUSIONS: Magnesium significantly reduced the shivering threshold. However, in view of the modest absolute reduction, this finding is considered to be clinically unimportant for induction of therapeutic hypothermia.

Adolescent↗

PubMed2005

Candidemia--an under-recognized nosocomial infection in Indian hospitals.

OBJECTIVE: To study the occurrence of candidemia as a nosocomial infection in a large Indian teaching hospital and to evaluate the predisposing factors for development of such infections. METHODS: One hundred and one hospitalized patients that developed signs and symptoms of nosocomial bloodstream infections were screened for candidemia and were analyzed for the various predisposing factors like the age of the patient, the duration of hospitalization before the development of fever, neutropenia, use of chemotherapeutic agents, central venous catheters, broad spectrum antibiotics, infection with HIV, diabetes mellitus, use of corticosteroids, administration of total parenteral nutrition, haemodialysis, use of mechanical ventilation, hematological or other malignancies, underlying disease, and any surgical procedure performed on the patient. Candidemic patients were followed up for outcome and the effect of nosocomial candidemia on mortality was assessed and analyzed statistically. RESULTS: Out of the 101 patients, seven patients had candidemia, an incidence in study population of 6.9%. Three (42.8%) were infected with albicans and the rest with non-albicans candidemia. All the patients with candidemia were admitted in the Intensive Care Units. Amongst the risk factors, the length of hospitalization (p = 0.018), broad-spectrum antibiotics (p = 0.045), central venous catheters (p = 0.005), mechanical ventilation (p = 0.0139) and total parenteral nutrition (p = 0.001) were found to be significantly related to acquisition of nosocomial candidemia. Mortality in the candidemic patients was influenced only by the age of the patients (p = 0.001). Although the mortality amongst the candidemic patients was twice as much as that of the patients not having this infection, still the difference did not reach significance (p = 0.117). CONCLUSION: Candidemia is an important problem in Indian hospitals. Diagnostic delays could be shortened by more active screening for candidemia especially in the intensive care settings. The rising incidence of non-albicans candidemia in the United States probably is true here as well. There should be a concerted effort to control known risk factors especially in intensive care units.

Adolescent↗

PubMed2005

Successful pregnancy in untreated limited Wegener's granulomatosis.

A thirty four year old female presented with upper and lower respiratory symptoms in the third trimester of pregnancy. After the delivery of a healthy baby, the symptoms progressed to involve multiple organ systems and eventually a diagnosis of limited Wegener's Granulomatosis (Carrington-Liebow syndrome) was made. The extremely rare combination of WG and pregnancy, especially the onset of disease in late pregnancy is discussed. The successful outcome of pregnancy even without treatment of WG is the highlight of the case.

Adult↗

PubMed2004

Block-dependent sedation during epidural anaesthesia is associated with delayed brainstem conduction.

BACKGROUND: Neuraxial anaesthesia produces a sedative and anaesthetic-sparing effect. Recent evidence suggests that spinal cord anaesthesia modifies reticulo-thalamo-cortical arousal by decreasing afferent sensory transmission. We hypothesized that epidural anaesthesia produces sensory deafferentation-dependent sedation that is associated with impairment of brainstem transmission. We used brainstem auditory evoked potentials (BAEP) to evaluate reticular function in 11 volunteers. METHODS: Epidural anaesthesia was induced with 2-chloroprocaine 2%. Haemodynamic and respiratory responses, sensory block level, sedation depth and BAEP were assessed throughout induction and resolution of epidural anaesthesia. Sedation was evaluated using verbal rating score (VRS), observer's assessment alertness/sedation (OAA/S) score, and bispectral index score (BIS). Prediction probability (PK) was used to associate sensory block with sedation, as well as BIS with other sedation measures. Spearman's rank order correlation was used to associate block level and sedation with the absolute and interpeak BAEP latencies. RESULTS: Sensory block level significantly predicted VRS (PK=0.747), OAA/S score (PK=0.748) and BIS. BIS predicted VRS and OAA/S score (PK=0.728). The latency of wave III of BAEP significantly correlated with sedation level (rho=0.335, P<0.01) and sensory block (rho=0.394, P<0.01). The other BAEP parameters did not change during epidural anaesthesia. Haemodynamic and respiratory responses remained stable throughout the study. CONCLUSIONS: Sedation during epidural anaesthesia depends on sensory block level and is associated with detectable block-dependent alterations in the brainstem auditory evoked responses. Sensory deafferentation may reduce CNS alertness through mechanisms related to brainstem neural activity.

Adult↗

PubMed2001

Interaction between pyrin and the apoptotic speck protein (ASC) modulates ASC-induced apoptosis.

Patients with familial Mediterranean fever suffer sporadic inflammatory attacks characterized by fever and intense pain (in joints, abdomen, or chest). Pyrin, the product of the MEFV locus, is a cytosolic protein whose function is unknown. Using pyrin as a "bait" to probe a yeast two-hybrid library made from neutrophil cDNA, we isolated apoptotic speck protein containing a caspase recruitment domain (CARD) (ASC), a proapoptotic protein that induces the formation of large cytosolic "specks" in transfected cells. We found that when HeLa cells are transfected with ASC, specks are formed. After co-transfection of cells with ASC plus wild type pyrin, an increase in speck-positive cells is found, and speck-positive cells show increased survival. Immunofluorescence studies show that pyrin co-localizes with ASC in specks. Speck localization requires exon 1 of pyrin, but exon 1 alone of pyrin does not result in an increase in the number of specks. Exon 1 of pyrin and exon 1 of ASC show 42% sequence similarity and resemble death domain-related structures in modeling studies. These findings link pyrin to apoptosis pathways and suggest that the modulation of cell survival may be a component of the pathophysiology of familial Mediterranean fever.

Actins↗

PubMed2001

Episodic evolution of pyrin in primates: human mutations recapitulate ancestral amino acid states.

Familial Mediterranean fever (FMF; MIM 249100) is an autosomal recessive disease characterized by recurrent attacks of fever with synovial, pleural or peritoneal inflammation. The disease is caused by mutations in the gene encoding the pyrin protein. Human population studies have revealed extremely high allele frequencies for several different pyrin mutations, leading to the conclusion that the mutant alleles confer a selective advantage. Here we examine the ret finger protein (rfp) domain (which contains most of the disease-causing mutations) of pyrin during primate evolution. Amino acids that cause human disease are often present as wild type in other species. This is true at positions 653 (a novel mutation), 680, 681, 726, 744 and 761. For several of these human mutations, the mutant represents the reappearance of an ancestral amino acid state. Examination of lineage-specific dN/dS ratios revealed a pattern consistent with the signature of episodic positive selection. Our data, together with previous human population studies, indicate that selective pressures may have caused functional evolution of pyrin in humans and other primates.

Amino Acid Sequence↗

PubMed2001

Large-dose oral dextromethorphan as an adjunct to patient-controlled analgesia with morphine after knee surgery.

Dextromethorphan is a weak N-methyl-d-aspartate (NMDA) receptor antagonist that inhibits spinal cord sensitization in animal models of pain and also inhibits the development of cutaneous secondary hyperalgesia after tissue trauma. Perhaps coadministration of an NMDA antagonist with an opioid would lead to better pain relief, particularly with movement and an opioid-sparing effect. This has been shown for ketamine, but previous studies with dextromethorphan that have used small doses have shown only a modest reduction in morphine requirements with no or minimal changes in the postoperative pain experience. We sought to determine whether a large dose of this drug, just below the maximum tolerated dose, could potentiate morphine analgesia while simultaneously causing a significant improvement in the management of the postoperative pain experience. Sixty-six patients undergoing knee surgery were enrolled in the study. The study design was a prospective, randomized double-blinded comparison with placebo of 200 mg of dextromethorphan given eight hourly. Postoperative pain experiences were assessed by postoperative morphine usage. Visual analog and verbal rating scales were used to assess pain with movement as well as side effects. Dextromethorphan treatment led to a significant but modest reduction in morphine requirements (29.3% P < 0.05) but no reduction in postoperative pain levels. We conclude that increasing orally administered dextromethorphan to near maximum tolerated doses does not provide greater morphine sparing than 20-40 mg given 6-8 hourly as in previous studies. Furthermore we conclude that dextromethorphan does not improve pain scores in a manner expected of a drug with NMDA antagonist properties.

Administration, Oral↗

PubMed1997

Nutritional status of the elderly.

Elderly become vulnerable to malnutrition owing to inappropriate dietary intake, poor economic status and social deprivation. Elderly are known to be easily subjected to inanition and avitaminosis resulting in multiple nutritional deficiencies. Urban slum dwellers, rural poor and those living alone appear to be at a higher risk of poor dietary intake. Though food consumption patterns of rural and urban elderly show a distinct difference, these are greatly influenced by regional dietary patterns. The diets of institutionalised and free living elderly reveal adequate nutrient intakes except iron and vitamin A. The nutrients least adequately supplied in the diets of Indian elderly are calcium, Iron, vitamin A, riboflavin and niacin along with energy deficits. Changes in body composition which mark the onset of the ageing process, include decline in lean body mass and increase in adipose tissue. A high prevalence of iron deficiency anaemia has also been reported among Indian elderly.

Aged↗

PubMed1994

Apraclonidine and brimonidine effects on anterior ocular and cardiovascular physiology in normal and sympathectomized monkeys.

Apraclonidine and brimonidine administered topically to one eye of ketamine-anesthetized normal cynomolgus monkeys each produced a dose-related bilateral reduction in intraocular pressure which was not dependent on intact sympathetic innervation. Brimonidine was more potent and efficacious (10-12 mmHg maximum intraocular pressure reduction 2 hr after 200 micrograms) but produced a shorter-lasting effect than apraclonidine (4 mmHg maximum intraocular pressure reduction 1-6 hr after 600-1000 micrograms). Apraclonidine had little effect on pupil diameter, but brimonidine produced a dose-related bilateral miosis which was dependent on intact sympathetic innervation. Neither drug significantly affected refractive error. Topical brimonidine, but not apraclonidine, produced a dose-dependent reduction in mean arterial blood pressure, while both drugs lowered heart rate. A dose-dependent bilateral reduction in aqueous humor flow rate calculated over a 6-hr period following drug administration was produced by both topical apraclonidine (maximum 30-35% reduction with 600 micrograms) and brimonidine (maximum 30-45% reduction with 50-250 micrograms), which was not dependent on intact sympathetic innervation. Maintenance of blood pressure by intravenous infusion of angiotensin II had no effect on the aqueous humor flow suppression produced by 100 micrograms of topical brimonidine, but pentobarbital anesthesia abolished it. Intracameral injection of 10 micrograms brimonidine in rhesus monkeys produced an ipsilateral approximately 15% reduction in aqueous humor flow calculated for the 1-3 hr post-injection period. The cardiovascular and contralateral ocular effects observed with both drugs are presumably related to the monkeys' small body weight, and the magnitude of IOP reduction for a given degree of flow suppression would be greater in hypertensive than in normotensive eyes. Caution must therefore be exercised in extrapolating from our data in ocular normotensive monkeys to the glaucomatous human.

Adrenergic alpha-Agonists↗

PubMed1992

Unusual presentation of poliomyelitis.

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Child↗

PubMed1992

Acute carbamazepine poisoning.

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Acute Disease↗

PubMed1991

Congenital syphilitic hepatitis.

Hepatitis is a known manifestation of congenital syphilis, however hepatitis developing during penicillin therapy is unknown. Ten patients of congenital syphilis were studied and serial liver enzymes were done before and after starting penicillin therapy. Eight of the ten patients developed hepatitis after initiating penicillin therapy. Whether hepatitis in these cases was secondary to toxic reaction to the products of treponemal lysis or an autoimmune reaction needs to be investigated.

Alanine Transaminase↗

PubMed1990

Clinical, histopathologic & immunologic features of cutaneous lesions in acute meningococcaemia.

Fifty children with culture proven acute meningococcaemia were studied during the winter outbreak of the disease in 1986-87. Purpuric lesions were seen in 60 per cent, erythematous papules in 32 per cent, faint pink macules in 28 per cent, conjunctival petechiae in 10 per cent and herpes labialis in 20 per cent. Histopathology of skin lesions showed that the primary damage was to the dermal vessels, the extent of damage depending on the type of skin involvement. Diplococci in Gram's stained sections were seen frequently in purpuric as compared to the other skin lesions. They were located in degenerating neutrophils, endothelial cells, fibrin clots or freely in the vascular lumen. Electron microscopic study showed vascular changes accompanied by a perivascular phagocytic response. Both light and electronmicroscopy indicated the involvement of the coagulative mechanism in the pathogenesis of meningococcaemia. However, clinical parameters of clotting were often within normal limits. In the case of a child (who died eventually), a low platelet count and prolonged coagulation indices were observed. Sera from some of the children were tested for the presence of antibodies against meningococci by indirect immunofluorescence. Antibodies were detected in the sera and they may have a role in regulating the severity and course of the illness. The significance of immunoglobulin deposits in the skin lesions is not clear.

Antibodies, Bacterial↗

PubMed1990