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Biomedical subjects

V Patwardhan

Publications and source records attributed to V Patwardhan.

10 recordsLinked to original sources
PubMed2004

Molecular phylogeny in 3-D.

Molecular phylogenetic trees are constructed in three dimensions relative to the distribution of MW and pl classes and immunocrossreactivity against polyclonal antibodies to lens crystallins, as well as multiple sequence alignment between amino acid sequences, coding nucleotide sequences and the gene nucleotide sequences for beta-globin. Euclidian distances are estimated to position species in x, y, z space by multidimensional scaling and merged with bootstrap-tested branching pattern of Fitch & Margoliash plots to obtain 3-D phylogenetic tree. Compared to single attributes, phylogenetic trees based on multiple parameters allow significant repositioning of rodents, chiroptera and primates.

Animals↗
PubMed2001

MR imaging in intramedullary cysticercosis.

Although intramedullary spinal cord cysticercosis (IMC) is uncommon, its presence is being increasingly recognised by magnetic resonance imaging. We studied six patients from an endemic region and present the MRI features and clinical correlation of IMC. Six patients who presented with para- or quadriplegia were studied by contrast enhanced spinal MRI. Prompted by the spinal lesions, all patients underwent brain MRI. Clinical data and laboratory studies were reviewed in all patients. Definite diagnosis was established in the form of response to drug therapy (n = 4) and histopathology (n = 2). Follow-up MRI studies of spine and brain were obtained in four patients 2 months after they started medical treatment, regardless of surgery. Five patients showed fusiform and focal enlargement of the spinal cord (cervical 2, thoracic 3). Well-defined cysts with a slightly hyperintense mural nodule were identified in five patients in Ti-weighted images (T1WI). All cysts were hyperintense on T2WI and merged with the surrounding oedema. Oedema extended one to three vertebral levels above or below the cyst. Post-contrast T1WI showed well-defined, ring enhancing lesions with smooth walls in all patients. Symptoms in all patients correlated with the level of the lesions. Brain studies demonstrated lesions in just two patients. Histopathological confirmation was obtained in two patients. Follow-up spinal MRI was normal in two patients, following 2 months of treatment while residual and smaller lesions were seen in two patients. Two patients were asymptomatic and denied follow-up MRI. MRI of spinal cysticercosis were typical of and similar to those seen in cerebral lesions in our patients and corresponded to the level of symptoms. All cysts were surrounded by oedema. Two of four patients showed residual lesions after 2 months of therapy and 33 % of patients showed concomitant intracranial lesions.

Adult↗
PubMed2001

Activin disrupts somitogenesis in cultured chick embryos.

The anatomical and cell biological aspects of somite formation in the chick embryo have been rather well studied. Molecular regulation of somitogenesis in vertebrates is just beginning to be understood. We have studied the effects of human recombinant activin on somitogenesis in gastrulating chick embryos cultured in vitro with a view to assessing the possible role of activin-related molecules in this phenomenon. Activin disrupted somitogenesis in treated embryos, resulting in the formation of abnormal, split or ectopic somites. Light microscopic examination indicated that the ability of activin to interfere with somitogenesis might be partly due to initiation of somite formation at ectopic sites. We show that these cells are indeed somitogenic by their expression of one of the earliest somite-specific marker genes, Pax3. Scanning electron microscopic examination of control and treated embryos revealed direct effects of activin on cell-cell interactions. Cells from treated embryos exhibited disrupted intercellular adhesion leading to large intercellular spaces, altered cell shapes and modification of cell surface protrusions. The effects of activin on somitogenesis appear to be specific, since the neural structures, which are generally more susceptible to chemical insults during gastrulation, were relatively less affected. The results clearly point to a role of activin-related molecules in somitogenesis in the chick embryo.

Activins↗
PubMed2000

The rostro-caudal position of cardiac myocytes affect their fate.

During chick embryogenesis, cells destined to form cardiac myocytes are located within the primitive streak at stage 3 in the same relative anterior-posterior distribution as in the prelooped heart. The most rostral cells contribute to the extreme anterior pole of the heart, the bulbus cordis, and the most caudal to the extreme posterior end, the sinoatrial region. After gastrulation, these cells commit to the myocyte lineage and, retaining their relative positions, migrate to the anterior lateral plate. From stages 5 to 10 they diversify into atrial and ventricular myocytes, with the former located posteriorly and the latter, anteriorly. To determine the effect of a change in the rostro-caudal position of these cells on their diversification, anterior lateral plate mesoderm and the underlying endoderm were cut and rotated 180 degrees along the longitudinal axis, at stages 4-8. The subsequent diversification of these precursor cells into atrial and ventricular myocytes was examined using lineage-specific markers. Our results showed that altering location along the longitudinal axis through stage 6 changed the normal fate of a precursor cell. The orientation of the overlying ectoderm did not alter normal morphogenesis or determination of fate.

Animals↗
PubMed1996

Cell surface alterations by taxol associated with abnormal morphogenesis in the chick embryo.

The anticancer drug taxol brings about its biological effects by altering the stability of microtubules. We have examined the effects of taxol on early morphogenesis in chick embryos cultured in vitro. Taxol induced various abnormalities in the developing nervous system, heart and somites as well as general retardation of development. SEM studies revealed that taxol treatment leads to dramatic alterations in the embryonic cell surfaces. Time-course experiments demonstrated that the action of taxol is very rapid and becomes evident within a few minutes at the ultrastructural level. Taxol thus throws embryonic cell adhesion and motility out of balance. This appears to be the major cause of abnormal morphogenesis in taxol-treated embryos.

Animals↗
PubMed1994

Mesoderm enhancing effect of human seminal plasma inhibin and its synthetic C-terminal nonapeptide fragment in the chick embryo.

Isomers of fibroblast growth factor and members of the transforming growth factor beta family have been identified as potent mesoderm inducing factors, particularly in amphibians. Activins belonging to the latter group are capable of inducing all types of mesoderm. Inhibins, also belonging to the same family of proteins have an exactly opposite biological action than activins in the adult organism. We have examined the effects of human seminal plasma inhibin on the early development of the chick embryo, where also activins appear to be important in mesoderm induction. Contrary to expectations, inhibin brought about stimulation of development of somites and heart, structures of mesodermal origin, and increase in the body length in more than 50% of the treated chick blastoderms. A synthetic fragment of human seminal plasma inhibin, a nonapeptide fragment of C-terminal end, also exhibited similar effects. In some cases the treatments resulted in completely abnormal development while in some increase in the number of somites was associated with abnormality in the anterior region. Our results demonstrate that human seminal plasma inhibin does not act as an inhibitor of mesoderm induction in the chick embryo but in amniotes inhibin-related molecules may have a role as mesoderm enhancers.

Amino Acid Sequence↗
PubMed1992

Physicochemical characterization and phylogenetic comparison of fish lens proteins.

The composition of soluble eye lens proteins from four chondropterygiian and fourteen teleostean fishes were analyzed for heterogeneity in MW and pI. Lens proteins from all the fish species studies are distributed in the pI range 4.3-9.0 with polypeptides in the range 17,500-31,000 Da. Phylogenetic trees are constructed based on the observations.

Animals↗
PubMedDate not supplied

The role of initial 5-fluorouracil trabeculectomy in primary glaucoma.

Sixty-eight patients with primary glaucoma involving 68 eyes were divided into two groups: Group I eyes were subjected to trabeculectomy (n = 38) and Group II eyes underwent trabeculectomy followed by subconjunctival injections of 5-fluorouracil (35 mg) (n = 30). After one year follow-up, Group I eyes exhibited reduction of mean intra-ocular tension from 45.7 mm Hg (pre-operative) to 16 mm Hg; optic disc cupping remained unchanged and 24/38 eyes (63%) were found to have field defects (19/38 i.e. 50% had preoperative field defects.) Group II eyes showed a reduction of mean intra-ocular pressure from 47.3 mmHg to 9.3 mmHg after one year. Mean cup disc ratio was lowered from 0.50:1 to 0.46:1 and 17/30 eyes (57%) which had field defects initially continued to exhibit the same. Complications in Group I and II eyes were shallow anterior chamber [8/38 eyes (21%) from Group I and 8/30 eyes (26%) from Group II], posterior synechiae formation in 10/38 eyes (26%) and 8/30 eyes (26%) and cataract progression in 13/38 eyes (34%) and 12/30 eyes (40%) respectively; only Group II eyes had transient superficial keratitis in 9/30 eyes (30%) and thin blebs in 6/30 eyes (20%). The use of 5-fluorouracil after trabeculectomy for primary glaucoma resulted in lowering of intra-ocular pressure, eliminated the need for antiglaucoma medications post-operatively, reduced the galucomatous cup size, and prevented progression of field loss without having a significantly increased complication rate.

Adult↗