PubMed Health⌕ Search

Biomedical subjects

V Shetty

Publications and source records attributed to V Shetty.

18 recordsLinked to original sources
PubMed1992

Biomechanical validation of the solitary lag screw technique for reducing mandibular angle fractures.

The purpose of this study was to determine whether the solitary lag screw technique meets the biomechanical demands of angle fractures. Simulated angle fractures in four cadaveric mandibles were reduced using solitary lag screws and the load-displacement relationships determined under functional loading of the individual mandibles. Subsequently, an angle fracture in a photoelastic mandible analog was fixed with a lag screw and subjected to similar loading. The mechanisms by which the solitary lag screw transferred functional loading were observed and recorded in a circular polariscope. Concomitant distraction tendencies were monitored and measured using displacement transducers. Correlation of the force-displacement measurements to photoelastic observation substantiated that the solitary lag screw functions as a tension band to provide a sufficient degree of interfragmentary compression and stability to withstand functional loading of the mandible.

Biomechanical Phenomena↗
PubMed1992

The role of an anti-myeloperoxidase antibody in the diagnosis and classification of acute leukaemia: a comparison with light and electron microscopy cytochemistry.

The enzyme myeloperoxidase (MPO) is the hallmark of the myeloid lineage. We have analysed the presence of MPO in blasts from 180 cases of acute leukaemia (103 acute myeloid leukaemia (AML) and 77 acute lymphoid leukaemia (ALL) by means of monoclonal antibodies anti-MPO and immunocytochemistry (alkaline phosphatase anti-alkaline phosphatase method). The aim of the study was to investigate the specificity and sensitivity of this marker compared with MPO cytochemistry by light (LM) and electron microscopy (EM), and with the expression of myeloid antigens. Anti-MPO was positive (greater than 3% blasts) in all but one of the 90 AML positive by LM cytochemistry. Of 13 AML cases negative by MPO cytochemistry, six showed 3-10% blasts reactive with anti-MPO and were also positive with antibodies to CD13 and/or CD33. The presence of MPO was confirmed in four of these by EM. The overall positivity of anti-MPO in AML was 92%. Anti-MPO was negative in all but two ALL (6% and 8% positive blasts). The blasts in these two cases were also CD13, CD33 and MPO positive by EM; both were thus reclassified as biphenotypic. Another two ALL reinterpreted as biphenotypic were negative by MPO cytochemistry and anti-MPO but were MPO positive by EM and with CD13 and/or CD33. We conclude that anti-MPO is a sensitive and specific early marker of myeloid blasts and should be incorporated in the routine immunophenotyping of acute leukaemia.

Acute Disease↗
PubMed1991

A classification of acute leukaemia for the 1990s.

The need for reproducibility in the classification of acute leukaemia has made it necessary to incorporate information derived from new techniques which have become essential for the study of these disorders. In addition to classic morphology and cytochemistry (FAB proposals), it is necessary to add immunology and cytogenetics (MIC proposals), as well as to investigate further the biological and diagnostic significance of molecular events. As a result of these investigations a new group of leukaemias merit recognition as distinct entities. These include three types of ALL with specific chromosome abnormalities, namely, i) t (9;22), ii) t (4;11) and iii) t (1;19) and four subtypes of AML, i) with minimal differentiation or AML-M0, ii) with basophilic precursors or M2Baso, iii) AML (M4/M5) with t (8;16) and iv) AML with trilineage myelodysplasia. Biphenotypic acute leukaemia constitutes also a distinct entity with features of ALL and AML and represents a malignancy probably affecting multipotent stem cells. We propose an objective evaluation system for biphenotypic leukaemias based on a score in which the various lineage markers are graded according to their known specificity.

Humans↗
PubMed1991

Preparation and evaluation of a nonproprietary bilayer skin substitute.

Cross-linked, allogeneic, telopeptide-depleted dermal grafts were lyophilized and laminated with silicone rubber elastomer. Resultant bilayers were studied for incorporation into the wound site and capacity to inhibit cutaneous wound contraction in experimental animals. Bilateral full-thickness skin wounds were made in 20 male New Zealand white rabbits. One side was grafted with the processed graft, while the contralateral side remained ungrafted as a control wound. Over 63 days, wound sites were analyzed at intervals on the basis of the extent and rate of wound contraction and by histologic examination. Cutaneous wounds successfully incorporated graft matrix and were significantly inhibited in their rate and extent of wound contraction. Notably, by day 63, grafted wounds retained 71 percent of their original area, whereas ungrafted control wounds retained only 16 percent of their original area. There were no graft rejections, and the bilayer graft's dermal analogue appeared to function as a biodegradable template that physically conformed neodermis to a preestablished pattern while counteracting contractile forces. This investigation suggests that, in experimental animals, the success of bilayer dermal grafts is less dependent on highly specialized and complex preparative techniques than typically has been presumed and that relatively simple, previously published, nonproprietary techniques, when adapted to a bilayer format, yield acceptable results as defined in terms of biocompatibility, capacity for graft incorporation, and inhibition of wound contraction.

Animals↗
PubMed1991

Alloplastic materials in reconstructive periodontal surgery.

Alloplastic implants, especially those made with calcium phosphate ceramics, are being increasingly used in reconstructive periodontal surgery. Despite attractive generic features such as good biocompatibility, these ceramic implants differ significantly from each other in terms of biologic profile. Variations in source material used, manufacturing process, and physical and chemical properties determine the clinical utility of these implants. Porous hydroxyapatites currently are favored, especially those with natural morphologic characteristics. These ceramic implants appear to serve as biocompatible fillers that accelerate bone healing when used for the right clinical indications. It is anticipated that alloplastic implants eventually will form a part of the periodontist's armamentarium.

Alveoloplasty↗
PubMed1990

Phenotypic, genotypic, cytochemical, and ultrastructural characterization of acute undifferentiated leukemia.

During the diagnostic investigation of 750 acute leukemias, nine cases were morphologically, cytochemically, and phenotypically undifferentiated. In seven of these cases the blasts were class II+, CD34+ and TdT+, in one were class II+, TdT+, CD7+ while in the remaining leukemia blasts expressed class II only. Cytoplasmic and membrane CD22, CD3, CD13, and Ig as well as membrane CD19, CD10, CD37, CD2, CD33, CD14, glycophorin C, and CD61 were absent. The further characterization of these rare leukemias yielded the following results. The TCR-beta, -gamma and -delta genes were in germline configuration in seven cases studied while IgH genes were rearranged on both alleles in two cases and germline in the other five. By ultrastructural analysis peroxidase activity was detected on unfixed cells in a minority of blasts from four of seven cases. In two of the peroxidase-positive cases a small proportion of blasts also reacted with an anti-myeloperoxidase monoclonal antibody. In one of the peroxidase-negative cases, 7% of blasts were labeled by the antibody, suggesting the presence of peroxidase in its proenzyme form. Importantly, the two cases with Ig gene rearrangements did not have cytochemically or immunologically detectable peroxidase. Three of the nine patients were treated as ALL while six received AML chemotherapy. In five patients complete remission was achieved while the other four died from infections during remission induction. Four patients are still in remission 7, 12, 24, and 30 months after diagnosis while one patient relapsed after 12 months. In conclusion, we have characterized the genotypic and ultrastructural features of subtype of acute leukemia in which blasts expressed immaturity markers and lacked lineage associated antigens. In contrast to previously reported "unclassifiable" cases, the leukemias were phenotypically homogeneous and showed a good response to chemotherapy.

Acute Disease↗
PubMed1989

Technical improvements in the sagittal split ramus osteotomy.

This article addresses the potential sources of morbidity associated with the sagittal split ramus osteotomy. Refinements in the instrumentation and technique are described; these enhance the exactness of the procedure, thereby minimizing the complications and improving the stability of the surgical result.

Bone Plates↗
PubMed1989

Teeth in the line of fracture: a review.

The management of teeth in the line of fracture is still controversial. This lack of consensus about what is appropriate therapy led to a review of the literature. The various opinions expressed are reappraised in the context of the new treatment modalities available today, and recommendations are made to help the surgeon in his decision making.

Humans↗
PubMed1987

Maxillomandibular fixation with minihooks: a clinical evaluation.

This article provides the clinical evaluation of a simple but effective method of maxillomandibular fixation that eliminates the morbidity attendant to the conventional methods of maxillomandibular fixation. The indications have been defined on the basis of the clinical experience with this technique.

Adolescent↗
PubMed1987

Solitary lag screw osteosynthesis in the treatment of fractures of the angle of the mandible: a retrospective study.

Various methods have been advocated for the treatment of fractures of the angle of the mandible, emphasizing the complexity of the problem. A functionally stable osteosynthesis can be achieved in such fractures with a solitary lag screw. This technique meets the principles of rigid internal fixation and achieves maximum stability with a minimum of implant material. It obviates the need for maxillomandibular fixation, as well as the morbidity associated with the conventional methods of treatment. A review is presented of 50 patients who were treated by this method. The data show that the procedure is an effective and predictable modality of treatment with a low rate of morbidity.

Adult↗
PubMed1976

Study of early nerve lesions in mice infected with M. leprae.

The present study is of quantitative histology in immunologically intact mice inoculated with M. leprae. Total twelve sciatic nerves are studied. The fibres are grouped as large, medium and small sized fibres. Initially there is loss of small size fibres. At later stages there is involvement of all sized fibres and ultimately Wallerian type of degeneration sets in. The process of regeneration is more active than that of human leprosy of tuberculoid type. This study adds a new dimension in understanding the pathogenesis of leprosy.

Animals↗
PubMedDate not supplied

Clinical, electrophysiological, quantitative, histologic and ultrastructural studies of the index branch of the radial cutaneous nerve in leprosy. I. Preliminary report.

The index branch of the radial cutaneous nerve has been demonstrated as a constant nerve which can readily biopsied under local anesthesia and yields a nerve which is of suitable size for quantitative and qualitative studies both by light and electron microscopy. It supplies a limited but constant area where the sensory loss does not disturb the patient. Definite ultrastructural changes have been demonstrated in the clinically normal nerves of leprosy patients. These nerves have also revealed a loss in the small myelinated and unmyelinated fibers, which correlated with the common clinical findings of the absence of sweating and dissociated sensory loss in this disease. Gross damage has been encountered in nerves which showed only early signs of clinical damage even with refined methods of sensory testing. These nerves would have passed as normal on routine testing by No. 5 nylon. Regeneration of small fibers was noted following loss of large size fibers. Nerve conduction velocity may be a useful tool in early diagnosis.

Action Potentials↗