Search PubMed⌕ Search

Biomedical subjects

A Gupta

Publications and source records attributed to A Gupta.

At least 163 records · Page 9Linked to original sources
PubMed2002

Thermosensitive chitosan-based hydrogel containing liposomes for the delivery of hydrophilic molecules.

A novel injectable in situ gelling thermosensitive chitosan-beta-glycerophosphate (C-GP) formulation has been recently proposed for tissue repair and drug delivery. The system can sustain the release of macromolecules over a period of several hours to a few days. However, with low-molecular-weight hydrophilic compounds, the release is generally completed within 24 h. In this study, liposomes were added to the C-GP solution and their effect on the viscoelastic properties of the system and release kinetics of encapsulated carboxyfluorescein was investigated. The gelation rate and gel strength were slightly increased by the presence of the liposomes. The in vitro release profiles demonstrated controlled delivery over at least 2 weeks. The release rate strongly depended on the liposome size and composition (i.e. addition of cholesterol), and on the presence of phospholipase in the release medium. The kinetics was not substantially modified when using liposomes prepared with a negatively-charged lipid or a lipid having a high phase transition temperature. These results indicate that the liposome-C-GP system rapidly gels at body temperature, and can sustain the delivery of low-molecular-weight hydrophilic compounds. A mathematical model was proposed to characterize the release kinetics.

Biocompatible Materials↗
PubMed2002

Noninvasive management of Indian visceral leishmaniasis: clinical application of diagnosis by K39 antigen strip testing at a kala-azar referral unit.

Firm diagnosis of visceral leishmaniasis (kala-azar) requires organ aspiration and microscopic examination of tissue specimens. To determine the usefulness of noninvasive diagnosis by strip test detection of anti-K39 immunoglobulin (Ig) G antibody in blood specimens obtained by fingerstick, 143 Indian patients with suspected kala-azar (fever, splenomegaly, anemia) were studied. Of 120 strip test-positive subjects (subjects with presumed kala-azar [group A]), amphotericin B treatment induced clinical cure in 119. Of 23 strip test-negative subjects (subjects presumed to have other diseases [group B]), 16 had other disorders diagnosed at entry, 4 responded to empiric antimalarial therapy, 2 were proven to have kala-azar, and 1 died elsewhere after undergoing splenic aspiration. Six months after treatment ended, all 120 patients in group A and the 18 assessable patients in group B were healthy. In a region in India where visceral infection is prevalent, strip test detection of anti-K39 IgG is a clinically promising diagnostic guide in persons with suspected kala-azar.

Adolescent↗
PubMed2002

Role of the general stress response during strong overexpression of a heterologous gene in Escherichia coli.

The strong overexpression of heterologous genes in Escherichia coli often leads to inhibition of cell growth, ribosome destruction, loss of culturability, and induction of stress responses, such as a heat shock-like response. Here we demonstrate that the general stress response, which is connected to the stress response regulator sigmas (sigma38, rpoS gene product), is suppressed during strong overproduction of a heterologous alpha-glucosidase. The mRNA levels of the rpoS and osmY stress genes drastically decrease after induction of the strong overexpression system. It is shown that an rpoS mutation causes a significant loss of cell viability after induction of the expression system. Furthermore, it is demonstrated that an E. coli c/pP mutant, which could be suggested to improve heterologous protein production, is not a good production host if a tac-promoter is used to control the expression of the recombinant gene. Data from this study suggest that the overexpression of the alpha-glucosidase was greatly decreased by sigma factor competition in the clpP mutant, due to the increased sigmas level in this mutant background.

Bacterial Proteins↗
PubMed2002

Effects of variation in cerebral haemodynamics during aneurysm surgery on brain tissue oxygen and metabolism.

OBJECTIVES: This study explores the sensitivities of multiparameter tissue gas sensors and microdialysis to variations in blood pressure, CSF drainage and to well-defined periods of ischaemia accompanying aneurysm surgery, and their predictive value for infarction. METHODS: A Neurotrend sensor [brain tissue partial pressure of oxygen (PBO2), carbon dioxide (PBCO2), brain pH (pHB) and temperature] and microdialysis catheter were inserted into the appropriate vascular territory prior to craniotomy. RESULTS: Baseline data showed a clear correlation between PBO2 and mean arterial pressure (MAP) below a threshold of 80 mmHg. PBO2 improved with CSF drainage in 20 out of 28 (Wilcoxon: P < 0.05) cases where data was available. In 26 patients the effects of temporary vascular clipping (TC) (mean duration 16 minutes) were assessed. 2 patients subsequently declared infarction in the region of the probes. PBO2 fell from a mean 3.2 (95% CI 2.4-4.1) kPa to a minimum of 1.5 (95% CI 1.0-2.0) kPa in the non-infarct group. There was a lower baseline PBO2 (mean 0.8 kPa) in the patients who infarcted. PBCO2 mirrored PBO2 changes, whereas pHB did not change significantly in either group. Microdialysis changes associated with decreased PBO2 included a delayed increase in lactate, a raised lactate/pyruvate ratio and more rarely an increased glutamate. These changes were seen in 11 patients but were not predictive of infarction. CONCLUSION: Hypotension during aneurysm surgery is associated with a low PBO2. Multiparameter sensors can be sensitive to acute ischaemia. Microdialysis shows potential in the detection of metabolic changes during tissue hypoxia.

Adult↗
PubMed2002

Risk factors for pneumonia in infants and young children and the role of solid fuel for cooking: a case-control study.

We evaluated the risk factors for childhood pneumonia with particular reference to indoor air-pollution associated with solid fuel use for cooking (e.g. coal, wood, dung), using a case-control study in a children's hospital in Calcutta. Cases were 127 children aged 2-35 months of either sex admitted with pneumonia and controls were 135 children attending their immunization clinic. Solid fuel use (odds ratio = 3.97, CI = 2.00-7.88), history of asthma in the child (OR = 5.49, CI = 2.37-12.74), poor economic status indicator (OR = 4.95, CI = 2.38 to 10.28), keeping large animals (OR = 6.03, CI = 1.13-32.27) were associated with high risk of pneumonia after adjusting for confounding (logistic regression analysis). Nearly 80% of people in India use such smoke producing fuel and the population attributable risk would be very high. This finding has important health policy implications. Furthermore, history of asthma is a useful prognostic indicator for early action for prevention of severe pneumonia.

Air Pollution, Indoor↗
PubMed2002

Stenosis of the hepatic vein anastomosis after liver transplantation: treatment with a heparin-coated metal stent.

Delayed-onset fibrotic stenosis of the hepatic-vein anastomosis following liver transplantation resulted in ascites and abnormal liver-function tests. The stenosis was treated with balloon dilatation resulting in a clinical improvement; however, this had to be repeated four times in the 9 months after transplantation due to recurrent stenosis. The stenosis was eventually successfully treated with percutaneous insertion of a metal stent. Aspirin 50 mg daily was prescribed for 1 month. The patient was not anticoagulated. The patient remains clinically well at follow up after 18 months.

Anastomosis, Surgical↗
PubMed2002

Alzheimer's disease and vascular factors: facts and theories.

Although Alzheimer s disease is classified as a neurodegenerative dementia, in Alzheimer s dementia there is increasing evidence of an association with vascular risk factors and vascular pathology. These observations are supported by epidemiological and pathological studies. Vascular factors may play a significant role in the pathogenesis of Alzheimer s dementia. Further research is needed to explore this relationship. Modification of vascular risk factors could make a significant impact towards prevention and treatment of Alzheimer s disease, which is a distressing and prevalent condition in the community. This article considers the relationship of these vascular risk factors and potential mechanisms associated with the aetiopathogenesis of Alzheimer s dementia.

Aged↗
PubMed2002

An unusual presentation of the Papillon-Lefevre syndrome as recurrent liver abscesses.

The Papillon-Lefevre syndrome is a rare genetic disorder with a predisposition to severe infections. We describe Papillon-Lefevre syndrome in a 17 year old boy from a family where four out of eight siblings were affected with this disease and who presented with recurrent pyogenic liver abscesses over a period of 9 years, an association never previously reported.

Adolescent↗
PubMed2002

Stroke prevention: missed opportunities?

Identification and modification of risk factors can prevent strokes. Certain previously unidentified risk factors for stroke can become apparent following admission with acute stroke. The aim of the study was to investigate the prior capture, identification and management of modifiable risk factors for stroke in patients admitted to a hospital following acute stroke. One hundred consecutive stroke patients admitted to a UK hospital were prospectively assessed for modifiable risk factors. The extent of pre-admission risk factor management was also determined. Pre-admission risk factors identified and effectively managed were hypertension in non-diabetics (28%), hypertension in diabetics (7%), previous cerebrovascular event (100%), diabetes (29%), smoking (50% counselled), atrial fibrillation (81%), hypercholesterolaemia (100%), excess alcohol (22% counselled) and obesity (52% counselled). Twenty-five new modifiable risk factors were identified following incident stroke. In conclusion, a significant number of patients admitted with acute stroke have their risk factors poorly identified and controlled in the community. Despite the trial evidence available, an evidence-practice gap exists and many stroke prevention opportunities are being missed.

Acute Disease↗
PubMed2002

Post-stroke depression.

Stroke is considered mainly as a physical disability, and stroke-related depression is under-recognised. Cognitive, language and functional impairment complicates the recognition of post-stroke depression. The pathophysiology of post-stroke depression is poorly understood, but several risk factors have been identified. Depression following stroke can impede recovery and rehabilitation and is associated with higher mortality Randomised trials show that antidepressants, especially selective serotonin uptake inhibitors, are effective in the treatment of this condition. Despite the evidence available, a large number of patients remain undertreated. Early identification and treatment can reduce the functional impairment and mortality related to post-stroke depression.

Antidepressive Agents↗
PubMed2002

Demonstration of scolex in calcified cysticercus lesion using gradient echo with or without corrected phase imaging and its clinical implications.

AIM: This study was performed to determine the magnetic resonance imaging (MRI) sequence that was best suited to demonstrate the scolex in a calcified lesion and to seek the explanation for the appearance of a negative phase in a calcified scolex on corrected gradient refocused echo (GRE) phase imaging. MATERIALS AND METHODS: Forty-nine patients with single/multiple computed tomography (CT) documented homogeneous calcified lesions and/or calcified scolices in cysts were studied with conventional spin echo and corrected GRE phase imaging. Calcium and different paramagnetic substances from cysticerci scolices of a sample of infected swine muscle were quantified. RESULTS: The scolex could be demonstrated in 29/39 patients with single calcified lesion. GRE imaging with an echo time of 35ms was the only sequence that demonstrated scolex in all these 29 cases. 15/29 patients with a single calcified lesion, in all 10 patients with multiple calcified lesions and infected swine muscle with multiple cysts and calcified scolex, corrected GRE phase imaging showed negative phase in all these scolices. Estimation of minerals from the calcified scolices from the swine muscle showed by spectroscopic techniques 41.2% of the total mineral contents as paramagnetic substances. CONCLUSION: We conclude that GRE imaging is the imaging method of choice for demonstration of the scolex in a CT calcified lesion. The negative phase on corrected GRE phase imaging is due to the presence of large amount of paramagnetic substances.

Adolescent↗
PubMed2002

Knowledge of stroke symptoms and risk factors among at-risk elderly patients in the UK.

Assessing patient knowledge can help healthcare providers in planning measures directed at prevention, early identification and referral of patients. An incorrect understanding of stroke symptoms may delay patients seeking emergency help, thus missing the benefits of acute stroke treatments. Insufficient knowledge about stroke risk factors may affect risk factor control. We conducted a questionnaire-based interview among elderly patients at risk of stroke and assessed their baseline knowledge of stroke symptoms and risk factors. A large proportion were found to have an improper understanding of stroke symptoms and risk factors. Stress was considered the commonest risk factor for stroke. Most patients did not consider themselves to be at further risk of stroke. Further education is needed as part of stroke prevention strategies to remove misconceptions. Improved recognition of stroke symptoms when they occur will help when seeking emergency medical help.

Aged↗
PubMed2002

A study of cardiovascular effects of Azadirachta indica (neem) on isolated perfused heart preparations.

The effects of aqueous leaf extract of Azadirachta indica were evaluated on isolated prefused frog and rabbit heart. Dose dependent negative inotropic and chronotropic effects were observed in both the heart preparation. An increase in coronary blood flow in isolated rabbit heart was observed. The effects were not blocked by atropine and mepyramine in both the preparations. The data suggests that A. indica could be of benefit in coronary artery disease and arrhythmias.

Animals↗
PubMed2002

Role of viral serology in the diagnosis of acute retinal necrosis syndrome.

Due to the devastating nature of acute retinal necrosis syndrome (ARNS), early diagnosis is essential. 5 cases of clinically diagnosed ARNA were investigated for CMC, herpes simplex and varicella zoster virus (VZV) infections. Of the three VZV IgM positive cases, two were positive in acute blood samples and one in vitreous fluid. Thus VZU can be incriminated as the causative agent of ARNS cases in North India.

Adult↗