Biomedical subjects

M Tata

Publications and source records attributed to M Tata.

8 recordsLinked to original sources

PubMed1999

A prospective comparison of stereotaxic fine-needle aspiration versus stereotaxic core needle biopsy for the diagnosis of mammographic abnormalities.

BACKGROUND: Confidence in a negative stereotaxic breast biopsy result allows for safe clinical and mammographic follow-up, whereas a positive or equivocal diagnosis leads to excision. Direct comparison of stereotaxic core needle biopsy (SCBX) and fine-needle aspiration (SFNA) is needed, and should be based on the use of appropriate current methods of practice, and address the indication of each for different types of mammographic lesions. METHODS: The diagnostic accuracy of SFNA, SCBX, and combined SFNA with SCBX performed at a community radiology practice were assessed for different mammographic lesions and levels of radiologic suspicion. Negative predictive values (NPVs) measured the confidence that a negative diagnosis (failure to identify atypia or malignancy) was benign and therefore suitable for follow-up. A benign outcome was accepted only after surgical excision or > or =24 months' follow-up of the lesion. Positive predictive values (PPVs) [final diagnoses at least atypical (A) or carcinoma (CA)] also were calculated. RESULTS: SFNA was performed for 495 lesions and was combined with SCBX for 252 of these. Nondiagnostic (SFNA, 2%; SCBX, 8%) and atypical (SFNA, 7%; SCBX, 3%) rates were low. The authors obtained 94% follow-up (81% > or = 24 months). NPVs were all SFNAs, 99%; SCBXs, 95% (corresponding SFNAs, 98%); and SFNA with SCBX, 99%. NPVs were 100% for masses, ill-defined densities, and architectural distortions. NPVs for microcalcifications (for low, moderate, and high suspicion) were all SFNAs, 97% (100, 95, and 75); SCBXs, 93% (94, 93, and 67), corresponding SFNAs, 96% (100, 94, 75); and SFNA with SCBX, 98% (100, 97, 75). All false-negative lesions were microcalcifications. Calcium was recognized in 98% of SFNA specimens and in 89% of SCBX specimens from microcalcifications. No calcium was identified in the histologic sections in 63% (5 of 8) SCBX false-negative specimens. PPVs(A) were atypical (SFNA, 46%; SCBX, 88%) and suspicious (SFNA, 93%). PPVs(CA) were SFNA carcinoma, 100%; SCBX in situ, 89%; and SCBX invasive, 100%. CONCLUSIONS: SFNA identified benign lesions more reliably for follow-up, particularly microcalcifications. Based on these results, the authors suggest 1) added SCBX if on-site SFNA assessment is nondiagnostic, atypical, or positive (and needs preoperative confirmation of invasion); 2) either SCBX or SFNA for masses, architectural distortions, and ill-defined densities; 3) SFNA for microcalcifications, with SCBX added for moderately and highly suspicious lesions; and 4) surgical excision for all highly suspicious microcalcifications.

Biopsy, Needle↗

PubMed1999

Spontaneous activity of rat dorsal horn cells in spinal segments of sciatic projection following transection of sciatic nerve or of corresponding dorsal roots.

Natural forms of stimulation were used to compare the spontaneous and evoked activity of dorsal horn neurons in three groups of rats: controls with no surgical lesion, rats with transection of the sciatic nerve and rats with transection of the dorsal roots at the same segmental level. In control rats, cells encountered in the dorsal horn were classified according to their peripheral field as tactile specific, convergent tactile and nociceptive, nociceptive, or movement driven. In 20 control animals, only 20% of the 140 cells with a peripheral field were spontaneously active. After sciatic nerve transection made on the side of recording a few days previously (18 rats), all of the 141 cells studied showed spontaneous activity, only 69 of them having a peripheral field. After dorsal root transections a few days previously (nine rats), 25 spontaneously active cells were found in the dorsal horn ipsilateral to the section, none with a peripheral field. Spontaneous activities of cells without a peripheral field were separated into three types as a function of bursting pattern, which were similar following both types of transection. The spontaneous activity shown by dorsal horn cells without peripheral fields following dorsal root transection precludes attribution of spontaneous spiking in such cells to abnormal input from the periphery, and shows that abnormal activity can develop in deafferented dorsal horn cells themselves. A possible role played by this spontaneous activity in deafferentation pain is considered.

Action Potentials↗

PubMed1999

Immobilized yeast bioreactor systems for continuous beer fermentation

Two different types of immobilized yeast bioreactors were examined for continuous fermentation of high-gravity worts. One of these is a fluidized bed reactor (FBR) that employs porous glass beads for yeast immobilization. The second system is a loop reactor containing a porous silicon carbide cartridge (SCCR) for immobilizing the yeast cells. Although there was some residual fermentable sugar in the SCCR system product, nearly complete attenuation of the wort sugars was achieved in either of the systems when operated as a two-stage process. Fermentation could be completed in these systems in only half the time required for a conventional batch process. Both the systems showed similar kinetics of extract consumption, and therefore similar volumetric productivity. As compared to the batch fermentation, total fusel alcohols were lower; total esters, while variable, were generally higher. The yeast biomass production was similar to that in a conventional fermentation process. As would be expected in an accelerated fermentation system, the levels of vicinal diketones (VDKs) were higher. To remove the VDKs, the young beer was heat-treated to convert the VDK precursors and processed through a packed bed immobilized yeast bioreactor for VDK assimilation. The finished product from the FBR system was found to be quite acceptable from a flavor perspective, albeit different from the product from a conventional batch process. Significantly shortened fermentation times demonstrate the feasibility of this technology for beer production.

Journal Article↗

PubMed1998

A comparison of proliferative activity and atypical mitoses in cervical condylomas with various HPV types.

Cervical condylomas associated with HPV types 6/11 rarely progress to dysplasia; this progression is more commonly seen in cervical condylomas with HPV types 16/18/31/33/35. This investigation was undertaken to determine if more frequent atypical mitotic figures (MFs) and higher proliferative activity are seen in high-risk condylomas. HPV types present in cervical condylomas were determined by in situ hybridization with biotinylated probes. The cases were also stained immunohistochemically for MIB1. The percentage staining of basal, parabasal, and suprabasal cells was determined by counting 100 cells in the most intensely stained areas. MFs and atypical MFs were counted per 10 high-power-fields (HPFs). Condylomas with HPV 6/11 showed higher MIB1 expression in the basal layer than condylomas with HPV 16/18 and 31/33/35 (p = 0.013). Atypical MFs were seen more frequently in condylomas with HPV types 16/18/31/33/35 (p = 0.02). Differences in mitotic activity and in MIB1 expression in parabasal and suprabasal layers did not reach statistical significance. The presence of atypical MFs may make a greater contribution than increased proliferative activity to progression to dysplasia in cervical condylomas.

Antigens, Nuclear↗

PubMed1995

Sinus histiocytosis mimicking metastatic melanoma in lymph nodes of a patient with a large joint prosthesis: case report and review of the literature.

Malignant melanoma metastases to regional lymph nodes may be mimicked by several non-neoplastic processes, including sinus histiocytosis induced by fragments shed from joint prostheses. A patient who had an elective lymph node dissection for malignant melanoma and was found to have "post-prosthesis lymph node histiocytosis" resembling metastatic disease is described. Knowledge of the patient's past history of a total shoulder joint replacement along with the use of polarized light microscopy to identify birefringent particles of prosthetic debris allows for an accurate histologic diagnosis.

Aged↗

PubMed1993

Visceral leishmaniasis in the acquired immunodeficiency syndrome: report of two cases.

Core biopsies of the bone marrow are indispensable in the evaluation of fever of unknown etiology in human immunodeficiency virus-positive patients. We report two patients in whom visceral leishmaniasis was diagnosed based on the typical morphology, staining characteristics, and ultrastructure of the organisms.

AIDS-Related Opportunistic Infections↗

PubMedDate not supplied

Melanocyte halo explained.

Electron microscopic examination was performed of skin biopsy specimens processed for electron microscopy directly after formaldehyde fixation, after retrieval from paraffin blocks, and as for paraffin embedding but with retrieval after clearing with xylene, the last step before paraffin infiltration. The halos surrounding melanocytes in the epidermis are a retraction artifact that develops during paraffin infiltration of the tissue. It is proposed that this artifact is related to the high temperature of the paraffin bath.

Artifacts↗

PubMedDate not supplied

Liver pathology in children with AIDS: a comparison between the South American and North American population.

Liver tissue from autopsies of twenty-nine cases of children with AIDS were collected from three major South America (S.4) pediatric hospitals. The hepatopathologic findings were classified in the same fashion as in a series of sixty-one children with AIDS from North America (NA): inflammation, non-specific, lymphoproliferative disorders, and giant cell transformation. By comparing both groups. we noted that the SA children were Younger at time of death consistent with a more rapid progression of the disease. Opportunistic infections varied with a higher prevalence of Cytomegalovirus (CMV) infection in SA children. The histopathologic features of CMV in the liter of SA children were associated with a conspicuous inflammation absent in the NA group. Finally, different non-specific hepatic changes were found in SA children, including one case of peliosis hepatis.

AIDS-Related Opportunistic Infections↗