Search PubMed⌕ Search

Biomedical subjects

A Aggarwal

Publications and source records attributed to A Aggarwal.

At least 199 records · Page 11Linked to original sources
PubMed1985

The use of monoclonal antibodies in studies of filarial parasite antigens.

The strength of the hybridoma technology in providing probes for the study of parasite immunology is obvious. The use of monoclonal antibodies should greatly expedite the task of the identification and the isolation of antigens which are relevant to host protection, of immunodiagnosis and of immunopathology. We have produced a series of monoclonal antibodies against Brugia malayi which causes lymphatic filariasis in man. One of these monoclonal antibodies (IgM isotype) can detect circulating antigens in the sera of individuals and of laboratory animals infected with B. malayi by radioimmunoprecipitation-PEG assay. This monoclonal antibody can bind to the relevant epitope of the circulating antigen or to the antigenic determinants of the immune complexes that remained exposed in the complex. A few monoclonal antibodies raised against B. malayi were selected, one of which gave positive fluorescence reaction on the surface of microfilariae. This particular monoclonal antibody showed such biological activities as conferring resistance to circulating microfilariae and inducing cell-mediated killing of microfilariae in vitro. The same monoclonal antibody was able to identify antigenic determinants (of mol. wt, 110 Kd) on the surface of B. malayi microfilariae which may be involved in effector mechanisms related to the development of transmission inhibiting immunity in lymphatic filariasis.

Animals↗
PubMed1983

Interactions of protein calorie malnutrition, malaria infection and immune responses.

The course of parasitaemia and certain immune responses in protein or calorie-deficient albino rats infected with Plasmodium berghei (NICD) were studied. Wide variations observed in the course of parasitaemia in protein-deficient animals were (a) prolonged prepatent period, short patent period with low parasitaemia (50% of animals), (b) short prepatent period and an inability to resolve the infection (14% of animals) and (c) no patent parasitaemia at any stage of observation (23.5% of animals). The calorie-deficient animals had significantly lower parasitaemia (P less than 0.05) compared with well fed animals. Protein deficiency resulted in depression of T-dependent immune responses in uninfected as well as P. berghei-infected animals. The outcome of the parasitaemia in protein- as well as calorie-deficient animals seems to be the combined result of deficiencies of certain essential nutrients, proteins and calories in the diet as well as the immune responses of the host.

Animals↗
PubMed1983

Variable virulence of isolates of Giardia lamblia in mice.

Groups of inbred mice were inoculated intraoesophageally with Giardia lamblia cysts isolated from the stools of 15 patients with various clinical conditions: symptomatic diarrhoeic, symptomatic non-diarrhoeic and asymptomatic cyst carriers. The virulence of these isolates was studied in terms of two-hour cyst excretion rate and trophozoite counts in the duodenum. The basic pattern of the cyst excretion was similar in all the groups: cysts appeared in the stools by Day 3 +/- 1, reaching a maximum by Day 11 +/- 2. There was then a gradual decline until Day 23 +/- 2, with a low output until Day 31 post-inoculation. However, statistically significantly higher numbers of cysts were excreted by animals which had received cysts isolated from symptomatic diarrhoeic patients than by mice which received cysts from symptomatic non-diarrhoeic or asymptomatic cases. Identical results were obtained with the trophozoite counts. Haemagglutinating (HA) antibodies appeared after Day 11 post-inoculation in each group regardless of different cyst isolates, and the HA titre increased until Day 31 post-inoculation. The results indicate that variable symptomatology in patients could be due to variation in the virulence of the parasite.

Adult↗
PubMed1980

The consequences of exposure to asbestos dust in a wartime gas-mask factory.

This further study of wartime gas-mask workers who were exposed to asbestos dust has shown that among those who worked with crocidolite there is a considerable excess of cases of mesothelioma, a more modest excess of bronchial carcinoma, but no excess of any other type of malignant disease. A dose-response relationship is established in the mesothelioma and bronchial carcinoma patients. It is not possible to base any conclusions on the limited data available for the small number of people exposed to chrysotile for a maximum period of five months. We believe that the identification and measurement of fibres in autoptic lung tissue from patients with accurately known occupational histories of asbestos dust exposure is useful, and a similar study on a population exclusively exposed to chrysotile would be of considerable interest.

Asbestos↗
PubMedDate not supplied

Mechanisms and dynamics of mechanical strengthening in ligament-equivalent fibroblast-populated collagen matrices.

We have measured the dynamics of extracellular matrix consolidation and strengthening by human dermal fibroblasts in hydrated collagen gels. Constraining matrix consolidation between two porous polyethylene posts held rigidly apart set up the mechanical stress which led to the formation of uniaxially oriented fibroblast-populated collagen matrices with a histology resembling a ligament. We measured the mechanical stiffness and tensile strength of these ligament equivalents (LEs) as a function of age at biweekly intervals up to 12 weeks in culture using a mechanical spectrometer customized for performing experiments under physiologic conditions. The LE load-strain curve changed as a function of LE age, increasing in stiffness and exhibiting less plastic-like behavior. At 12 weeks, LEs had acquired up to 30 times the breaking strength of 1-week-old LEs. Matrix strengthening occurred primarily through the formation of BAPN-sensitive, lysyl oxidase catalyzed crosslinks. Sulfated glycosaminoglycan (GAG) content increased monotonically with LE age, reaching levels that are characteristic of ligaments. Cells in the LEs actively incorporated [3H]proline and [35S]sulfate into the extracellular matrix. Over the first three weeks, DNA content increased rapidly but thereafter remained constant. This data represent the first documentation of strengthening kinetics for cell-assembled biopolymer gels and the results suggest that this LE tissue may be a valuable model for studying the cellular processes responsible for tissue growth, repair, and remodeling.

Age Factors↗
PubMedDate not supplied

Juvenile rheumatoid arthritis in India--rarity of antinuclear antibody and uveitis.

Juvenile chronic arthritis is a heterogeneous disease, having different subtypes. Among our 89 patients with juvenile chronic arthritis, we did not find even one patient with early onset pauciarticular disease with uveitis and antinuclear antibody positivity. Further, the prevalence of anti-nuclear antibodies and anti-histone antibodies was very low whereas the prevalence of rheumatoid factor was similar to that reported from Western countries. Thus, the spectrum of juvenile chronic arthritis in India differs from that seen in the west. Larger population based studies of the disease are thus needed.

Adolescent↗
PubMedDate not supplied

CT diagnosis of Meckel diverticulum in a paracolic internal hernia.

The autopsy incidence of internal hernia has been reported to be between 0.2% and 0.9%, and these hernias are usually diagnosed on imaging due to their complications or at surgery. Meckel diverticulum is the most common congenital anomaly of the gastrointestinal tract, occurring in 1% to 3% of the population according to autopsy studies. The condition also is usually diagnosed at surgery, by barium studies or scintigraphy, or on cross-sectional imaging due to complications. We present an unusual case of a large Meckel diverticulum in a right paracolic hernia diagnosed on multidetector computed tomography. This diagnosis was made after attacks of subacute intestinal obstruction with the aid of multiplanar reconstructions. This case emphasizes the role of multidetector computed tomography and postprocessing techniques such as multiplanar reconstruction in the diagnosis of bowel pathology.

Adult↗
PubMedDate not supplied

Steam vaporizer burn injuries.

Steam vaporizers increase indoor relative humidity by releasing steam into the air. The temperature of the steam is sufficiently high to cause severe burns. We report two cases of children who received partial thickness burns from steam vaporizers. Because of the high risk of burn injury, the manufacturers should be required to label the surface of the boiling chamber of the vaporizer with a warning statement.

Burns↗
PubMedDate not supplied

Diastolic dysfunction: pathophysiology, clinical features, and assessment with radionuclide methods.

Basic to our understanding of heart failure is the distinction between systolic and diastolic ventricular dysfunction. Diastolic dysfunction implies that the ventricle cannot accept blood at normally low pressures. The ventricular filling pattern and the relation between ventricular diastolic pressure and volume reflect a dynamic interaction between time course of relaxation, conversion of elastic forces into elastic recoil, and the passive properties of the ventricle. In the early part of diastolic filling, the pressure-volume relationship is influenced primarily by relaxation; in the latter part of diastole, passive filling properties are important. Mitral inflow patterns reflect these time-varying filling dynamics and are commonly assessed with echocardiography. Disorders of diastolic filling are observed in patients with heart failure with normal ejection fraction, myocardial ischemia, and even dilated cardiomyopathy. Patients with concentric ventricular hypertrophy, normal ejection fraction, and heart failure are the prototype of patients with diastolic dysfunction. In this article we review the physiology and pathophysiology of diastole and the main clinical disorders associated with diastolic dysfunction, and we outline in brief the application of radionuclide techniques in the assessment of diastolic dysfunction.

Cardiomyopathies↗
PubMedDate not supplied

Chitosan microspheres prepared by an aqueous process: release of indomethacin.

Chitosan microspheres loaded with indomethacin were prepared using only aqueous solvents. The influence of formulation variables on indomethacin content in the microspheres and time for release of 66.6% of indomethacin from the microspheres was investigated. Amongst various variables, the indoemthacin:chitosan ratio and amount of crosslinking agent were important. Response surfaces were generated to optimise the aqueous process with respect to these critical variables, in order to obtain maximum indomethacin loading and optimum t66.6.

Capsules↗