Biomedical subjects

R T Patil

Publications and source records attributed to R T Patil.

7 recordsLinked to original sources

PubMed2004

Transport across liquid membranes containing vitamin A (retinol acetate).

The role of the surface activity of vitamin A has been studied in the light of the liquid membrane hypothesis of drug action. Transport of relevant amino acids such as serine, threonine, arginine, and histidine and various ions such as calcium, sodium, and potassium in the presence of liquid membranes generated by vitamin A has been studied. The data on the modifications in the permeability of relevant amino acids and ions indicate that the liquid membranes generated by vitamin A may also play a significant role in its physiological action.

Algorithms↗

PubMed2001

Role of liquid membrane phenomenon in biological actions of ACE inhibitors, captopril and lisinopril.

The liquid membrane phenomenon in angiotensin converting enzyme (ACE) inhibitors namely, captopril and lisinopril has been studied. Hydraulic permeability data have been obtained to demonstrate the existence of the liquid membrane in series with a supporting membrane generated by the ACE inhibitors. Data on the transport of the relevant permeants in presence of the liquid membrane formed by ACE inhibitors indicate that liquid membrane phenomenon is likely to play a significant role in the action of ACE inhibitors.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed2000

A quantitative luminescence assay for measuring cell uptake of aqueous-based microcapsules in vitro.

We recently developed a system of microencapsulation consisting of aqueous-based polymers (e.g. alginate) and aqueous amines (e.g. spermine). We found that microencapsulation enhanced virus-specific protective immune responses. In addition, we found that microencapsulation may enhance virus-specific immune responses by selecting for antigen-presenting cells (APC) that are more efficient at processing and presenting viral antigens than those involved after natural infection. To determine the intracellular trafficking patterns and fate of microcapsules within APC, we developed a luminescence assay that permits the determination of specific quantities of proteins introduced into cells by microcapsules. We found that the time-dependent uptake of horseradish peroxidase (HRP)-labeled microcapsules was accurately detected in lysates of peritoneal exudate cells using luminol. The amplitude of HRP-catalyzed chemiluminescence in cell lysates correlated with the capture efficiency and retention kinetics of HRP in three different microcapsule preparations. HRP was most efficiently captured and retained by linking biotinylated HRP to microcapsulses chemically modified at the amine moiety with egg avidin. This preparation yielded more accurate and sensitive quantitation of HRP contained within cells than preparations capturing HRP or HRP-conjugated goat antibody into the microcapsular matrix by ionic interactions.

Animals↗

PubMed2000

Water-based microsphere delivery system for proteins.

This paper describes formulation of a model protein, horseradish peroxidase (HRP), in a water based microcapsule delivery system and demonstrates the utility of this delivery system for proteins. Aqueous solutions (1 mg/mL) of the enzyme were separately blended with aqueous solutions of the neutral sodium salt of the anionic polymer iota carrageenan (0.6 mM in repeat unit). These blends were instilled as uniform microdroplets into aqueous solutions of a series of eleven mono-, di-, or oligo-amines (as neutral hydrochloride or acetate salts). Essentially instantaneous salt exchange interaction of the sodium salt of anionic polymer with amine hydrochloride resulted in formation of microparticles of amine/polymer complex. The enzyme was captured in the resulting capsules. The particles were washed by repeated centrifugation and resuspension in water and their particle size distribution was determined. HRP in washed pelleted microspheres was analyzed for fragmentation/aggregation by SDS-PAGE and size exclusion chromatography, for unfolding by fluorescence spectroscopy, and for specific enzymatic activity, capture efficiency and release studies by absorbance spectroscopy. Dependent on amine employed, capture efficiencies ranged from 1 to 72%. Encapsulation produced no adverse effect on protein size as no molecular fragments or aggregates were visible below or above 44 kDa. The tryptophan fluorescence spectrum of the protein did not change after encapsulation indicating no conformational change in tertiary structure. There was an apparent substrate diffusion related reduction in activity of encapsulated HRP, but almost 100% of activity was recovered on lysis of the capsules. It is concluded that water based charged film encapsulation used as a drug delivery system for proteins does not alter structural conformation or specific activity of the model protein tested and provides protein release at a constant rate.

Carrageenan↗

PubMedDate not supplied

Retention of trypsin activity in spermine alginate microcapsules.

We have previously shown virus particles encapsulated in aqueous spermine alginate constructs retain immunogenicity and infectivity both in vitro and in vivo. However, because virions are complex structures with multiple reinforcing components, it was uncertain if isolated single proteins would retain functional integrity when similarly encapsulated. To examine this question trypsin, used as a model protein, was blended with aqueous sodium alginate and the blend was dispersed as fine droplets in aqueous spermine hydrochloride to generate self-assembling, trypsin-containing microcapsules. Trypsin was assayed spectrophotometrically for retention of enzymatic activity using N-alpha-p-tosyl-L-arginine methyl ester as substrate. Neither of the encapsulating reagents alone inhibited enzyme activity. Enzyme that escaped capture was assayed directly in the manufacturing supernatant. In mass balance studies we found that about 20-30% of activity was retained in intact capsules with the remainder resident in the aqueous manufacturing supernatant and washes. However, we found that the capsule wall appeared to inhibit enzyme activity by retarding substrate diffusion into and product diffusion out from the capsules, as evidenced by an increase in activity on lysis. Thus, it is clear that a single protein, as represented by trypsin, can retain functional integrity when encapsulated in this all aqueous system.

Alginates↗

PubMedDate not supplied

Amine composition influences apparent activity of enzyme in charged film microcapsules.

It has been shown that, when captured in charged film microcapsules prepared from spermine alginate, intact viruses retain infectivity, isolated viral proteins retain immunogenicity, and trypsin retains enzymatic activity. However, it was unclear whether the greater anionic strength of hemisulfate residues such as those in carrageenan might alter protein conformation and activity unfavourably in comparison with the lesser influence of alginate carboxylates. Further, the influence of the structure of the amine used to prepare the capsules was largely unknown. To examine these questions, trypsin, used as a model protein, was encased in microcapsules prepared from iota-carrageenan and oligoamines drawn from either the homologous series spermine, spermidine, putrescine or ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine. The gross structures of encapsulated and native trypsin were compared by denaturing electrophoresis and their enzymatic activity by the method of Hummel. In all encapsulations SDS PAGE gave no evidence of alteration of protein structure. When encapsulated, the apparent activity of trypsin was reduced by about 60 to 75%, but when the capsules were lysed in hypertonic saline activity was restored. This apparent reduction in activity is attributed to the diffusional barrier imposed by the encapsulating membrane but it should be recognized that it may be the result of reversible denaturation.

Alginates↗

PubMedDate not supplied

Actinomycotic mycetoma due to Nocardia brasiliensis in a case of leprosy.

Various bacterial and fungal infections associated with non-healing ulcers in cases of leprosy have been reported (G Ebenzer et al, 2000, Rama Ramani et al, 1990). There are no reports of mycetoma associated with leprosy patients in the literature. We report here a case of actinomycotic mycetoma due to Nocardia brasiliensis associated with the non-healing plantar ulcer of a leprosy patient.

Actinomycosis↗