Biomedical subjects

Tapan K Bhattacharyya

Publications and source records attributed to Tapan K Bhattacharyya.

5 recordsLinked to original sources

PubMed2004

Fibrin tissue adhesive and autologous concha cartilage for reconstruction of the posterior-superior canal wall of the chinchilla middle ear.

HYPOTHESIS: We conducted this study to prove that fibrin tissue adhesive (FTA) is safe, efficacious, biocompatible, and readily biodegradable with no deleterious side effects for fixation of a cartilage graft to bone along the chinchilla canal wall. METHODS: A posterior-superior canal defect was created in 12 chinchillas. The canal walls of six chinchillas were closed with autologous concha cartilage alone, whereas the canal wall of the remaining six animals were closed with cartilage in conjunction with fibrin tissue adhesive. RESULTS: Animals were killed 8 weeks postoperatively. Three of six cartilage grafts were displaced in the graft alone group, whereas all six grafts in the cartilage with FTA group healed without displacement. CONCLUSION: Fibrin tissue adhesive was found to be effective, biocompatible, biodegradable, and without any deleterious side effects for reconstruction of the superior-posterior canal wall of chinchillas.

Animals↗

PubMed2003

Histological evaluations following 1,064-nm Nd:YAG laser resurfacing.

BACKGROUND AND OBJECTIVES: The long pulse 1,064-nm Nd:YAG laser is used clinically to decrease rhytid formation. The dermal level at which this change occurs has not been established. This study attempts to answer these questions using a porcine skin model. STUDY DESIGN/MATERIALS AND METHODS: Non-randomized prospective experimental trial involving the domestic piglet treated serially with the long pulse 1,064-nm Nd:YAG laser. RESULTS: Collagen formation occurred at the level of the reticular dermis. After one laser treatment, a significant level of collagen formation was induced in the reticular dermis compared to controls. The greatest gain was observed after four laser treatments. Energy levels of 20, 30, 40, and 50 J/cm2 were evaluated. Although not statistically significant, 30 J/cm2 had the greatest effect on collagen formation. However, at 50 J/cm2, marked ablative changes to the epidermis were observed. CONCLUSIONS: The long pulse 1,064-nm Nd:YAG laser induces collagen formation in the reticular dermis in porcine skin.

Animals↗

PubMedDate not supplied

Histomorphologic changes in aging skin: observations in the CBA mouse model.

BACKGROUND: Aging of human skin is a phenomenon resulting from a combination of chronological aging and environmental stressors such as sunlight. OBJECTIVES: To study the effects of intrinsic aging on the skin in laboratory-raised CBA mice in 3 age groups, and to assess histological alterations as a function of age in this model. METHODS: Skin samples from CBA mice in 3 age groups (young, young adult, and old) were obtained from the dorsal and ventral areas, pinna, and hind foot to study the following variables using light microscopic manual morphometric methods: the depth of the epidermis and number of epidermal cells, depth of the dermis, and percentage area of dermal collagen, elastic fibers, pilosebaceous units, blood vessels, and tissue space. The obtained values were analyzed using 1-way analysis of variance to detect any significant effects of age. RESULTS: There was a notable attrition of the epidermal thickness and number of cells that could be correlated with age. A reduced number of pilosebaceous units was noted in skin samples from the dorsal region and the footpad. No conspicuous change was noted in the depth of the dermis or percentage area of collagen in aging animals. A proliferation of stainable elastic fibers was demonstrated in the dorsal skin and footpad of older mice. CONCLUSIONS: CBA mice show unique age-related histological modifications of the skin that are different from other rodent species. These baseline data will be helpful in further studies of regenerative effects of pharmaceutical agents on the histological structure of skin and in photoaging studies.

Aging↗

PubMedDate not supplied

Modulation of cutaneous aging with calorie restriction in Fischer 344 rats: a histological study.

OBJECTIVE: To examine whether histological changes in skin owing to intrinsic aging in a laboratory rodent model are modulated by caloric restriction (CR). METHODS: The abdominal skin from colony-raised ad libitum-fed Fischer 344 rats and age-matched rats subjected to CR was studied in the light microscope using histological morphometric methods. Animals 4, 12, and 24 months or older were used in this study. We studied the skin to obtain (1) quantitative data on the depth of the epidermis, dermis, and fat layer, the epidermal cellular density, the percentage fraction of dermal collagen, elastic fibers, pilosebaceous units, and capillaries, and the fibroblast density; and (2) qualitative assessment of histological staining for dermal glycosaminoglycans. We analyzed data by means of general linear model 2-way analysis of variance to obtain significance for the effects of age, diet, and age-diet interaction. RESULTS: The ad libitum-fed rats showed age-related increase in the depth of the epidermis, dermis, and fat layer. Calorie restriction prevented these changes, but epidermal nuclear density appeared to be stimulated. A trend toward increased values for collagen and elastic fibers, fibroblasts, and capillaries in skin samples from CR rats was observed. Pilosebaceous units were not modified. Moderately reduced staining for the dermal glycosaminoglycans in the skin of CR rats was noticed. CONCLUSIONS: Histomorphological changes resulting from intrinsic aging affected some of the studied variables in the rat skin, and these changes were delayed or prevented by CR. Some stimulatory effects, such as increased densities of fibroblasts and capillary profiles and higher values of connective tissue fibers resulting from CR, were also observed. Cutaneous morphological changes due to natural aging in this rat model seem to be modified by physiological or metabolic alterations imposed by CR.

Analysis of Variance↗

PubMedDate not supplied

Vestibular cytotoxicity in gentamicin-treated frogs: a preliminary report.

OBJECTIVE: The aim of this study is to determine the immediate effects of intraperitoneal doses of gentamicin (GM) which would result in variable degrees of destruction of crista ampullary hair cells of frogs. This information will serve as a baseline guide to cell regeneration experiments on the damaged vestibular sense organ. STUDY DESIGN: The American bullfrog was administered daily intraperitoneal doses of 50, 100, 150, and 200 mg/kg of GM for 7 days. Animals were sacrificed 1 day after the final injection for cytomorphic evaluation. Histologically processed posterior semicircular duct cristae were resin-embedded, and tissue samples were subjected to serial cross sectioning of the crista from the periphery to the central zone using glass knives in an ultramicrotome. Stained sections were analyzed in light microscope using ocular grid micrometry. The areal density of nuclear profiles of the vestibular sensory and supporting cells (sensory cells [SNCs] and supporting cells [SPCs], respectively; number per square millimeter) and the nuclear diameter of SNCs were manually determined. RESULTS: A 7-day administration of GM produced noticeable quantitative alteration of the posterior crista hair cells and SPCs. Histological analysis revealed a significant decrease in the density of SNCs and a concomitant increase in the density of SPCs (1-way analysis of variance). CONCLUSION AND SIGNIFICANCE: The cytomorphic data derived from this study show that 4 doses of intraperitoneal gentamicin administered to the bullfrog caused a decline in the areal density of sensory hair cells of the posterior canal crista ampullaris. Also noted was an increase in the density of adjacent SPCs. Although speculative, the increase in SPC population could be a harbinger of regeneration of the vestibular hair cells as suggested by other investigators in different species. The significance of present observations will be helpful to initiate future studies related to recovery of SNCs in a similarly damaged frog ampullary organ. Through a standardized quantitative approach to the study of SNCs and SPCs of the crista organ, the vestibulo-toxicity of newly developed drugs can be assessed.

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