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Biomedical subjects

R Arora

Publications and source records attributed to R Arora.

At least 199 records · Page 11Linked to original sources
PubMed1988

In Vivo Perturbation of Membrane-Associated Calcium by Freeze-Thaw Stress in Onion Bulb Cells : Simulation of This Perturbation in Extracellular KCl and Alleviation by Calcium.

Incipient freeze-thaw stress in onion bulb scale tissue is known to cause enhanced efflux of K(+), along with small but significant loss of cellular Ca(2+). During the post-thaw period, irreversibly injured cells undergo a cytological aberration, namely, ;protoplasmic swelling.' This cellular symptom is thought to be caused by replacement of Ca(2+) from membrane by extracellular K(+) and subsequent perturbation of K(+) transport properties of plasma membrane. In the present study, onion (Allium cepa L. cv Sweet Sandwich) bulbs were slowly frozen to either -8.5 degrees C or -11.5 degrees C and thawed over ice. Inner epidermal peels from bulb scales were treated with fluorescein diacetate for assessing viability. In these cells, membrane-associated calcium was determined using chlorotetracycline fluorescence microscopy combined with image analysis. Increased freezing stress and tissue infiltration (visual water-soaking) were paralleled by increased ion leakage. Freezing injury (-11.5 degrees C; irreversible) caused a specific and substantial loss of membrane-associated Ca(2+) compared to control. Loss of membrane-associated Ca(2+) caused by moderate stress (-8.5 degrees C; reversible) was much less relative to -11.5 degrees C treatment. Ion efflux and Ca(2+)-chlorotetracycline fluorescence showed a negative relationship. Extracellular KCl treatment simulated freeze-thaw stress by causing a similar loss of membrane-associated calcium. This loss was dramatically reduced by presence of extracellular CaCl(2). Our results suggest that the loss of membrane-associated Ca(2+), in part, plays a role in initiation and progression of freezing injury.

Journal Article↗
PubMed1988

Keratomycosis--a retrospective histopathologic and microbiologic analysis.

In this retrospective study, the results of concurrent histopathologic and microbiologic examinations of 61 corneal buttons were evaluated. These revealed histologic fungus identification in 77.04% of cases compared with culture examination which yielded fungal growth in 75.4% of cases. Mixed fungal and bacterial infection caused difficulty not only in isolation but also in demonstrating fungus in the tissue sections. Staphylococcus epidermidis was the most common isolate in cases of mixed infection. Aspergillus was the most prevalent nondematiaceous fungus. Dematiaceous fungi were isolated in culture in only 10.8% of our cases, and in none of them was the histopathology positive, indicating that they might have been contaminants.

Abscess↗
PubMed1988

Drug use in dermatology.

Prescription of drugs was studied for 197 outpatients and 93 inpatients seeking treatment under the specialized services of the Dermatology Department of the Nehru Hospital attached to the Postgraduate Institute of Medical Education and Research, (PGIMER) Chandigarh. Disease patterns in both settings and drugs prescribed for them were analyzed from prescriptions, retrospectively. Brand drugs were prescribed to the tune of 60-65%, in both settings, some lacunae in prescription are discussed.

Drug Utilization↗
PubMed1987

Bilateral simultaneous corneal graft rejection--role of tear immunoglobulins.

A report is made on an unusual case of corneal graft which was clear for well over a decade, and then manifested allograft rejection phenomenon concurrently in both eyes initiated by keratoplasty in the second eye. A bilateral and simultaneous corneal graft rejection in an individual does not seem to have been reported previously. Serial tear immunoglobulin (IgG) levels, which were normal in the initial postoperative period, demonstrated an elevation throughout the rejection phenomenon. The possible significance of this rise in the tear IgG levels is discussed.

Adult↗
PubMed1987

Cystic lesions of conjunctiva.

Cystic lesions constituted 37% of all the conjunctival specimens received over a period of 6 1/2 years. Epithelial inclusion cysts were the most common, followed by dermoid and parasitic cysts. A clinicopathologic correlation, along with an attempt at classification of cystic lesions of conjunctiva, is made in this article.

Adolescent↗
PubMed1986

Immunofluorescence studies of florid rheumatic Aschoff lesions.

We studied cardiac tissues of a patient who died of severe rheumatic myocarditis. Multiple Aschoff lesions were present throughout both ventricles and auricles. Immunofluorescence studies showed large monocytoid cells staining with OKM1 and anti-Leu M-3 as well as anti-Ia. Scattered T cells in areas of focal myocarditis stained with OKT3. Parallel staining for cardiac myosin-heavy chain antigens showed patchy dissolution of cardiac muscle fibers and traces of cardiac myosin within large monocytoid Aschoff cells.

Adult↗
PubMed1986

Protoplasmic Swelling as a Symptom of Freezing Injury in Onion Bulb Cells : Its Simulation in Extracellular KCl and Prevention by Calcium.

Freezing injury, in onion bulb tissue, is known to cause enhanced K(+) efflux accompanied by a small but significant loss of Ca(2+) following incipient freezing injury and swelling of protoplasm during the postthaw secondary injury. The protoplasmic swelling of the cell is thought to be caused by the passive influx of extracellular K(+) into the cell followed by water uptake. Using outer epidermal layer of unfrozen onion bulb scales (Allium cepa L. cv Big Red), we were able to stimulate the irreversible freezing injury symptoms, by bathing epidermal cells in 50 millimolar KCl. These symptoms were prevented by adding 20 millimolar CaCl(2) to the extracellular KCl solution. Our results provide evidence that loss of cellular Ca(2+) plays an important role in the initiation and the progression of freezing injury.

Journal Article↗
PubMed1986

Therapeutic goals: quality and quantity of life.

The elderly population is projected to increase from the present 11 per cent of the overall population to 20 per cent by the year 2020. The efforts of the medical community are directed toward extending the quantity of life. However, economic necessity and technologic advance in medicine will dictate the health care delivery to the elderly, as quality of life becomes a major factor in therapeutic decision making.

Adrenergic beta-Antagonists↗
PubMed1983

Tissue distribution of lymphocytes in rheumatic heart valves as defined by monoclonal anti-T cell antibodies.

Fresh cardiac valvular tissues and atrial appendages removed from 106 Indian patients with rheumatic heart disease at the time of corrective cardiac surgery were examined to determine the characteristics of valvular interstitial lymphocytic infiltrates using conventional histologic staining along with indirect immunofluorescent techniques. Precise identification of the phenotypic profiles of inflammatory mononuclear cells was attempted using anti-IgG, anti-Ia, and monoclonal mouse hybridoma reagents identifying T cells (OKT3) as well as T cell subsets (OKT4 helper/inducer and OKT8 suppressor/cytotoxic cells). A similar group of 21 patients undergoing cardiac valvular resection in Albuquerque was studied. The mean age of Indian patients providing valve tissues was 27.7, whereas in those in Albuquerque, it was 52 years. Twenty-five percent of rheumatic heart valves in Indian patients showed significant interstitial lymphoid infiltrates, and one third of the rheumatic valves from patients in Albuquerque showed similar mononuclear cell collections. Lymphoid infiltrates contained a predominance of T cells (70 to 80 percent) and only occasional B cells. Most of the T cells were OKT4-positive, with only a minor representation of suppressor/cytotoxic OKT8-positive T cells. In many instances, OKT4-positive helper T cell collections were closely juxtaposed to fibroblasts and collagen fibrils. These findings suggest that the chronic rheumatic scarring process may involve helper/inducer T cells as an ancillary factor in the indolent contracture and fibrosis of deformed cardiac valvular structures. Attempts to demonstrate residual streptococcal antigens by indirect immunofluorescence using a wide panel of heterologous rabbit F(ab')2 reagents with specificity for group A streptococcal membranes, cell wall mucopeptide, or group A carbohydrate gave negative results.

Adult↗
PubMed1982

Mid-diastolic aortic valve opening in bacterial endocarditis of aortic valve.

Echocardiographic features of acute aortic regurgitation resulting from bacterial endocarditis have been well documented (Nathan et al., 1980; Weaver et al., 1977; Wray, 1975a), and include thick shaggy echoes from aortic valve in diastole, fine diastolic flutter of aortic valves suggestive of rupture of cusps, and premature closure of mitral valves. Echocardiography being a sensitive noninvasive technique for detecting aortic valve vegetations is heavily relied on for earlier diagnosis and prompt therapy of these patients. Prognosis of echocardiographically positive endocarditis is known to be worse than for echo-negative patients. The following case is being presented because of an unusual echocardiographic manifestation with mid-diastolic aortic valve opening secondary to flail aortic valve from staphylococcal endocarditis of the aortic valve.

Adult↗