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Biomedical subjects

P Venkatesh

Publications and source records attributed to P Venkatesh.

At least 19 recordsLinked to original sources
PubMed2002

Posterior subtenon injection of corticosteroids using polytetrafluoroethylene (PTFE) intravenous cannula.

Injection of corticosteroids into the posterior subtenon space is a well established and highly effective modality in the treatment of intermediate uveitis. The conventional technique of posterior subtenon injection involves the use of a sharp tipped 26-gauge, 5/8 inch needle that must be inserted up to its hub to obtain adequate placement of the drug into the posterior subtenon space. With this technique the risk of perforation of the globe, although minimal, remains a potential complication. Herein is described a new technique for injection of corticosteroids into the posterior subtenon space using an intravenous cannula made of polytetrafluoroethylene (PFTE) that allows safer delivery of the drug into the posterior subtenon space.

Catheterization, Peripheral↗
PubMed2002

Posterior vitreous wick syndrome: a potential cause of endophthalmitis following vitreo-retinal surgery.

Endophthalmitis following pars-plana procedures such as a vitrectomy vitreo-retinal procedures has been infrequently reported in literature. The cited incidence is about 0.1% to 0.2%. In the 8 cases of endophthalmitis that have been reported in literature, the prognosis has been indicated as very poor due to a delay in diagnosis (1-3). Also, no possible source of an inoculum of the pathogenic organism reaching the vitreous cavity has been considered in these reports. We have encountered a few cases of endophthalmitis following vitreo-retinal surgeries at our tertiary eye care centre. Here again not being able to identify the possible source of infectious spread, we now report for the first time in literature, a new entity, the 'posterior vitreous wick syndrome'. This potential source of infectious spread, to the best of our knowledge, has not been considered earlier. We describe the patho-mechanism of the 'posterior vitreous wick syndrome' and also suggest methods of reducing its occurrence during vitreo-retinal procedures. This could also be the patho-mechanism of endophthalmitis following inadvertent loss of scleral integrity during extraocular surgeries like retinal detachment surgery and strabismus surgery (4,5).

Adult↗
PubMed2001

Phototoxic retinopathy.

Although the occurrence of iatrogenic light-induced retinal toxicity is beyond doubt, several issues remain to be studied further. These include conflicting reports regarding the wavelength of light that is most hazardous; what mechanism contributes more significantly in the pathogenesis of light-induced retinal toxicity-photochemical or photothermal; why does it occur in only some patients; and what is the protective role of UV absorbing chromophores in intraocular implants. Nevertheless, it is important for all ophthalmic surgeons to be aware of this complication and take measures that could decrease the risk of its occurrence.

Animals↗
PubMed2000

Congenital porphyria with necrotizing scleritis in a 9-year-old child.

Porphyria is a rare metabolic disorder that is characterized by the accumulation of photosensitive, toxic intermediates of the heme metabolic pathway in various organs of the body including the skin, eye and neural tissue. Porphyria as a potential cause for bilateral necrotizing scleritis in children is very infrequently emphasized in literature, probably due to the relatively rare occurrence and lack of well-documented cases. A case of a 9-year-old child with congenital porphyria who had developed necrotizing scleral ulceration in both eyes in addition to severe cutaneous hypersensitivity and facial disfigurement is herein presented.

Atropine↗
PubMed2000

Study of the first contact management profile of cases of infectious keratitis: a hospital-based study.

PURPOSE: To study the management pattern and examine the role of cultures and antibiotic sensitivity testing in infectious keratitis. METHODS: A retrospective analysis of the demographic, clinical, and microbiological data was performed in 100 consecutive patients with infectious keratitis. The main parameters evaluated were nature of first contact with the health care services, investigations undertaken, treatment initiated, and the time interval between presentation to the first medical contact and to our center. Finally, the reports of culture and antibiotic sensitivity testing undertaken at our center were evaluated. RESULTS: In 70% of cases, ophthalmologists in independent practice were the first medical contact. Direct microscopy of the corneal scraping was undertaken in only 6% of cases, whereas culture and sensitivity studies had not been performed in any of the patients. Forty-six percent of the patients were prescribed 0.3% ciprofloxacin eyedrops in an inadequate dosage. Broad-spectrum fortified antibiotics eye drops had not been prescribed in any of the cases. At our center, positive cultures were obtained in 73.86% of cases and the most common organism isolated was coagulase-negative Staphylococcus (33.84%), followed by Pseudomonas aeruginosa (15.38%). A large number of the isolates demonstrated resistance to the recommended antibiotic therapy. CONCLUSIONS: Failure to implement standard management protocol for infectious keratitis at first contact is a major factor contributing to ocular morbidity in India.

Adult↗
PubMed2000

Osseous choristoma of the choroid.

Osseous choristoma of the choroid, also called choroidal osteoma, is a very rare and unusual form of intraocular ossification. We report a case of choroidal osteoma in a young healthy male that to the best of our knowledge is the first report from India.

Adult↗
PubMed2000

New approaches in the management of choroidal neovascular membrane in age-related macular degeneration.

Age-related macular degeneration (AMD) is a leading cause of blindness in the elderly population. The prevalence is reported to be 1.2-1.4% in several population-based epidemiological studies. Currently 25-30 million people worldwide are blind due to AMD. With the aging world population it is bound to increase significantly, and could become a significant public health problem in next two decades, with serious socio-economic implications. Several strategies are today available to treat the wet form of AMD, which is responsible for significant visual loss. These were until recently confined to laser photocoagulation, and subretinal surgery, but today two other modalities, namely, radiation and photodynamic therapy, are available. These treatment modalities however, are aimed at preservation of vision only, and not at reversing the process of the disease. Further research on antiangiogenic drugs and gene therapy could significantly help AMD patients.

Blindness↗
PubMed1999

Role of polyphenol oxidase and peroxidase in the generation of black tea theaflavins.

It has been reported earlier that when macerated tea leaf is fermented at lower pH, the resultant black tea contains increased levels of theaflavin, an important quality marker in black tea. In an attempt to investigate the biochemistry and chemistry underlying this observation, in vitro oxidation experiments using polyphenol oxidase (PPO) from fresh tea leaves, horseradish peroxidase (POD), and tea catechins, precursors for theaflavins, were carried out. In vitro oxidation experiments using crude tea PPO resulted in higher content of theaflavins at pH 4.5 in comparison with pH 5.5, the normal pH of the macerated tea leaf. When purified PPO was used in the in vitro system, surprisingly a reversal of this trend was observed, with more theaflavins being formed at the higher pH. A combination of pure tea PPO and POD led to an observation similar to that with the crude enzyme preparation, suggesting a possible role for POD in the formation or degradation of theaflavin. POD was observed to oxidize theaflavins in the presence of H(2)O(2), leading to the formation of thearubigin, another black tea pigment. This paper demonstrates that tea PPO, while oxidizing catechins, generates H(2)O(2). The amount of H(2)O(2) produced is greater at pH 5.5, the optimum pH for PPO activity, than at pH 4.5. Hence, an observed increase of theaflavins in black teas fermented at pH 4.5 appears to be due to lower turnover of formed theaflavins into thearubigins.

Biflavonoids↗
PubMed1999

Surgical removal of a free floating cyst of the iris pigment epithelium causing disturbing visual symptoms.

Pigmented cysts in the anterior chamber, fixed or free floating, are considered to be unusual but not very infrequent. However, most of these cases usually do not need any treatment other than a periodic observation. We report the surgical removal of an iris pigment epithelial cyst floating freely in the anterior chamber. The reason for surgical removal was, disturbance in near vision being caused by movement of the cyst across the visual axis. This specific symptom of disturbed near vision, to the best of our knowledge, is a rare indication for surgery that has not been pointed out earlier. Histopathological confirmation of the clinical diagnosis was also obtained.

Adult↗
PubMed1999

Combined central retinal artery and central retinal vein occlusion following pars plana vitrectomy.

Combined occlusion of the central retinal artery and central retinal vein is an infrequently encountered clinical entity. Although there are reports in the literature of a combined occlusion of the central retinal artery and vein, its occurrence following pars plana vitrectomy has not been described. We report the case of an elderly patient who developed this unusual occurrence following an uneventful pars plana vitrectomy for a posteriorly dislocated IOL.

Aged↗
PubMed1997

The Control Preferences Scale.

The Control Preferences Scale (CPS) was developed to measure a construct that emerged from a grounded theory of how treatment decisions are made among people with life-threatening illnesses. The control preferences construct is defined as "the degree of control an individual wants to assume when decisions are being made about medical treatment." The CPS consists of five cards that each portrays a different role in treatment decision-making using a statement and a cartoon. These roles range from the individual making the treatment decisions, through the individual making the decisions jointly with the physician, to the physician making the decisions. The CPS involves subjects in making a series of paired comparisons to provide their total preference order over the five cards. These preference orders are analyzed using unfolding theory to determine the distribution of preferences in different populations and the effect of covariates on consumer preferences. The scale has been tested in a variety of populations, ranging from the general public to highly stressed groups. The CPS has proven to be a clinically relevant, easily administered, valid, and reliable measure of preferred roles in health-care decision-making.

Critical Illness↗
PubMed1996

Interphase cytogenetics of workers exposed to benzene.

Fluorescence in situ hybridization (FISH) is a powerful new technique that allows numerical chromosome aberrations (aneuploidy) to be detected in interphase cells. In previous studies, FISH has been used to demonstrate that the benzene metabolites hydroquinone and 1,2,4-benzenetriol induce aneuploidy of chromosomes 7 and 9 in cultures of human cells. In the present study, we used an interphase FISH procedure to perform cytogenetic analyses on the blood cells of 43 workers exposed to benzene (median = 31 ppm, 8-hr time-weighted average) and 44 matched controls from Shanghai, China. High benzene exposure (> 31 ppm, n = 22) increased the hyperdiploid frequency of chromosome 9 (p < 0.01), but lower exposure (< or = 31 ppm, n = 21) did not. Trisomy 9 was the major form of benzene-induced hyperdiploidy. The level of hyperploidy in exposed workers correlated with their urinary phenol level (r = 0.58, p < 0.0001), a measure of internal benzene dose. A significant correlation was also found between hyperdiploidy and decreased absolute lymphocyte count, an indicator of benzene hematotoxicity, in the exposed group (r = -0.44, p = 0.003) but not in controls (r = -0.09, p = 0.58). These results show that high benzene exposure induces aneuploidy of chromosome 9 in nondiseased individuals, with trisomy being the most prevalent form. They further highlight the usefulness of interphase cytogenetics and FISH for the rapid and sensitive detection of aneuploidy in exposed human populations.

Adult↗
PubMed1996

Learning to care: gender issues for male nursing students.

The following article is a description of one aspect of a phenomenological research study designed to investigate the lived experience of male nursing students as they learned to care as nurses. Data-collection strategies included paradigm case narratives and interviews. Data analysis was characterized by four major strategies: analysis, synthesis, criticism, and understanding. These strategies were used to identify meanings of the text of transcribed interviews and to generate interpretive commentary. Learning to care was described by the participants as a complex entity that incorporates the gender of the student, the patient, the teacher, and the nurse. As students progressed through the program, their experience of gender issues in learning to care was shaped by personal experiences, the expectations of a predominantly female faculty and nursing staff, and their evolving understanding of the ways of caring that are gender based.

Adolescent↗
PubMed1996

A struggle for equality: resistance to commissioning of male nurses in the Canadian military, 1952-1967.

Historical research was conducted to explore and describe the forces of resistance that prevented male registered nurses from being employed and conferred officer status in the Nursing Division of the Canadian military. Prior to 1967, only female nurses were permitted to join the Nursing Division. A 25-year struggle by the Registered Nurses Association of Ontario (RNAO), its Male Nurses Committee (MNC), and the Canadian Nurses Association (CNA) was required to change this discriminatory policy. The struggle for equality on behalf of Canadian male nurses was successfully resolved because of the united stand taken by the MNC, the RNAO, and the CNA. The study also demonstrates the need to move beyond matriarchal history perspectives in nursing to more completely understand the evolution of the profession in Canada.

Canada↗
PubMed1995

How male nursing students learn to care.

the current definitions of caring in nursing education denote a mutual relationship between teachers and students in which they interact to provide an environment which supports the students' personal and professional development. The learning of caring in an interactional context is typical of the female experience. It is unknown if this is representative of the male experience. The lived experience of 20 male students as they learned to care as nurses was the focus of this phenomenological research study. The participants concurred that, although caring as a nurse could be learned if one was 'open to learning', teachers could only facilitate this learning; they could not directly teach it. The interactional strategies of storytelling, modelling, being cared for, the 'aha' encounter, and observing and giving care, were used by the participants in learning to care as nurses. The implications of these findings for nursing education and research are presented.

Adult↗