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Biomedical subjects

N Arora

Publications and source records attributed to N Arora.

At least 73 records · Page 4Linked to original sources
PubMed1992

Evaluation of protein assay methods for pollen and fungal spore extracts.

The usual procedures available for protein estimation of biological extracts often give variable results due to presence of many peptides and coloured materials. To identify a suitable method for allergenic extracts, protein was estimated from common pollen and fungal antigens by modified Lowry's (ML), Bradford (B), micro-Kjeldahl (MK), Bicinchoninic acid (BCA) and modified BCA (MBCA) assays. Bradford assay resulted in low protein values, whereas BCA method gave very high values in general. Statistical analysis of the results revealed similarity between protein values quantitated by MK, ML and MBCA methods for most of the extracts. Graded volumes of the extracts on subjecting to protein estimation by these three methods showed linear response, while recovery of a protein (bovine serum albumin) added to the extracts was greater than 90%.

Allergens↗
PubMed1992

A study on antigenic and allergenic changes during storage in three different biological extracts.

The stability of three allergens common in tropical countries was evaluated under different storage conditions. Prosopis juliflora (PJ), Rhizopus nigricans (RN), and wheat dust (WD), were taken as representatives of various groups of allergens viz, pollen, fungi and dust. The extracts were stored in buffer containing phenol (0.4%) or glycerol (50%) at temperatures ranging from 4-55 degrees C for 15 to 60 days. Protein content of PJ extract was reduced remarkably when it was stored at 40 degrees C for 45 days. Thin layer isoelectric focusing and rocket immunoelectrophoresis of PJ showed that certain antigenic proteins degrade rapidly even at 25 degrees C as early as day 15. However, two to three proteins of PJ remain stable at a higher temperature (40 degrees C) for two months. Relative radioallergosorbent test (RAST) inhibition showed substantial loss of allergenic activity in all the three extracts, when stored at higher temperatures (25-55 degrees C) even for short durations, i.e., 15 days. Extracts (PJ and RN) containing 50% glycerol were found to be stable, retaining more than 50% activity, even when stored at 55 degrees C for 40 days, while extracts without glycerol lost more than 75% of their allergenic activity. However, addition of glycerol did not change the stability of wheat dust allergenic extract. The present findings indicate that allergenic extracts behave differently when stored. Hence, the stability of each extract should be determined individually.

Allergens↗
PubMed1991

Liposomes as vehicle for allergen presentation in the immunotherapy of allergic diseases.

Liposomes are non-toxic, biodegradable and weakly immunogenic lipid vesicles which can be used as immunomodulating agents. In the present study, multilamellar vesicles (MLV) and small unilamellar vesicles (SUV) were used to incorporate an allergenic protein from Artemisia scoparia pollen. MLV incorporated more allergenic protein than SUV. To assess the immunomodulating effect of allergen entrapped in liposomes, Swiss strain mice (made IgE responders) were injected with either free allergen or liposome-entrapped allergen (LEA) and their immune response was measured in terms of specific IgG and specific IgE levels. Results indicated that specific IgE response was significantly lower in mice injected LEA (P less than 0.02) than in mice injected free allergenic protein. Although specific IgG response was higher in mice injected LEA, there was no statistically significant difference between the two groups. Potential use of liposomes as non-immunogenic biocompatible vehicle for antigen presentation in immunotherapy will be discussed.

Allergens↗
PubMed1991

Sudden blindness associated with central nervous symptoms in a hemodialysis patient.

Purtscher's-like retinopathy as a cause of sudden blindness in hemodialysis patients is not widely known. This is believed to occur secondary to leukoembolization to retinal arterioles following complement activation. We describe a patient who developed sudden but reversible loss of vision on hemodialysis associated with varying reversible neurological signs and symptoms which we felt may have been a manifestation of leukoembolic aggregates lodging in the arterioles of the retina and central nervous system circulations.

Adult↗
PubMed1990

Immunomodulation by liposome entrapped allergen.

Liposomes are non-toxic, biodegradable and feebly immunogenic lipid vesicles made from natural and synthetic lipids. They are known to act as immunopotentiating agents and can be used to formulate sustained release preparation by encapsulation. In the present study, liposome entrapped allergen and free allergen were used to inject in Balb/C mice at different time intervals and their immune response in terms of specific IgG and specific IgE levels was quantitated by ELISA (Enzyme Linked Immuno sorbent Assay). The results indicated that specific IgE response was significantly higher in mice injected free allergen as compared to that of mice given liposome entrapped allergen. However, the specific IgG response was not statistically significant. Experiments carried out with liposome entrapped allergen and liposome coupled allergen showed no statistically significant difference in specific IgE and specific IgG titre between the two groups of mice. This type of immunomodulatory effect of liposomes in reducing IgE levels and without affecting IgG levels may be useful in Type I allergic disorders.

Allergens↗
PubMed1990

Radio-active iodine uptake in vitiligo.

Vitiligo and thyroid disease are commonly associated disorders. Twenty-two clinically euthyroid vitiligo patients were studied for functional assessment of thyroid by radioactive iodine uptake assay. Half of them showed abnormal uptake values at 24 hours. Of these patients, 90% had lower values indicating a tendency towards developing hypothyroid state. Subclinical thyroid dysfunction in vitiligo appears to be an adaptive change.

Adult↗
PubMed1990

Allergens entrapped in liposomes reduce allergenicity and induce immunogenicity on repeated injections in mice.

Liposomes which are nontoxic, biodegradable and biocompatible lipid vesicles are known to act as adjuvants and can be used to formulate sustained release preparation by encapsulation. In the present study, allergen entrapped in liposomes were injected at different time intervals in Swiss mice (made responders to IgE by injecting cyclophosphamide) and Balb/C mice (high IgE responders). Tissue distribution studies after intraperitoneal injection of allergen (entrapped and untrapped) revealed that liposome-entrapped allergen was retained for a longer time in all the tissues except kidney as compared to the free allergen given similarly. It was observed that serum specific IgG antibody levels were higher and specific IgE levels were lower in animals given repeated injections of liposomes-entrapped allergen as compared to those animals injected free allergen in the same manner. The entrapment of allergen in liposomes somehow suppressed the specific IgE response on repeated injections. The immunomodulatory effect of liposomes may be useful in the immunotherapy of respiratory allergic disorders.

Adjuvants, Immunologic↗
PubMed1990

Feasibility of in-center staff-assisted cycler dialysis.

Many debilitated elderly patients are not currently considered for peritoneal dialysis because they cannot perform the procedure themselves and they lack adequate back-up support in the family or extended care facility. They often tolerate hemodialysis poorly, and may exhaust their vascular access sites. We have provided intermittent in-center staff-assisted cycler dialysis to two debilitated elderly patients for a total of 12 patient months. Initial peritoneal equilibration tests indicated high solute transport rates in both patients, and led us to evolve a regimen based on frequent cycles. We use a 4 days a week regimen, cycling 12-14 liters during a 7.5 hour period each day. The patients tolerated the treatment well, with improved control of fluid balance and maintenance or improvement in appetite compared to baseline periods of CAPD. Mean pre-treatment BUN is 87 mg/dl. This is 29% higher than during CAPD, and has been stable. The requirement for additional nursing care has been variable but not disruptive of other activities once we established a dedicated space and routine. Current cycler technology permits consideration of in-center cycling as a practical alternative for many patients previously excluded from peritoneal dialysis.

Aged↗
PubMed1990

Biochemical studies into variation and repeatability of glutathione concentrations in bovine and bubaline semens.

Repeatability (r) value of glutathione (GSH) content was estimated in semen of Tharparkar, Red Dane, their crosses, and Murrah buffalo bulls. Mean GSH values were higher in bovine bull semen as compared to mean GSH values in bubaline bull semen. The r of GSH concentration for the pooled data was 0.1278. This trait is 12.78% repeatable. GSH value in semen of bovine and bubaline bull differed insignificantly. R estimates are expressed for selection of bulls of higher fertility and semen quality.

Animals↗
PubMed1989

Immunochemical characterization of cocos nucifera pollen.

The Cocos nucifera pollen, as one of the sources of allergen responsible for immediate hypersensitivity reaction, was confirmed by skin prick test, bronchial provocation test, and RAST. The whole pollen extract (WPE) of C. nucifera was fractionated by combination of gel filtration and ion-exchange columns with fast protein liquid chromatography (Pharmacia, Uppsala, Sweden). Three protein peaks designated Cocos II, Cocos VI, and Cocos VII exhibited allergenic properties, as tested by skin prick test, direct IgE ELISA, bronchial provocation test, and immunoblot analysis. In RAST inhibition, Cocos IIa (a high-molecular-weight protein) obtained by fractionation of Cocos II on Mono Q column (fast protein liquid chromatography) (Pharmacia) was found to be the most potent allergen in Cocos WPE, followed by Cocos VI and Cocos VII, which are low-molecular-weight proteins. The reference patterns of Cocos WPE on crossed immunoelectrophoresis and thin-layer isoelectric focusing were established for future standardization of Cocos WPE to be used in the diagnosis and immunotherapy of allergic patients.

Allergens↗
PubMed1989

Effect of phenylbutazone on acute hemorrhagic pancreatitis in dogs.

Experiments were conducted on 24 mongrel dogs to study the effect of phenylbutazone on acute experimental pancreatitis. Necrotico-hemorrhagic pancreatitis was produced by local infiltration of autologous bile. The severity of pancreatitis was assessed by biochemical estimation and histopathological examination. Pretreatment with phenylbutazone reduced the severity of pancreatitis, both biochemically and histologically (total score 6.0 +/- 1.52 in the test group vs 8.33 +/- 1.80 in the control group; p less than 0.01).

Animals↗