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Biomedical subjects

D Talwar

Publications and source records attributed to D Talwar.

At least 19 recordsLinked to original sources
PubMed1992

Sudden vision loss following retinal detachment surgery.

A 22-year-old man with Eales' disease with secondary rhegmatogenous retinal detachment with a break five disc diameters from the disc underwent radial scleral buckling using a silicone sponge episcleral explant with local cryopexy. Five hours after surgery the patient had no light perception. There was no intraoperative or postoperative rise of intraocular pressure or central retinal artery ischemia. Immediate removal of the explant brought a return of light perception and postoperative visual acuity improvement. The episcleral explant may have caused the direct optic nerve trauma that resulted in loss of vision.

Adult↗
PubMed1991

Ultrasonography in optic nerve head avulsion.

The diagnosis of post traumatic optic nerve avulsion is often obscured by the presence of concomitant vitreous haemorrhage. Electrodiagnostic tests, CT scan and fluorescein angiography have not proved helpful in substantiating the diagnosis of this entity in the early stages. We herein present the echographic features in a case of post traumatic optic nerve avulsion that, to the best of our knowledge, have not been previously described. The role of ultrasonography in the diagnosis of suspected optic nerve head avulsion has been high-lighted.

Adolescent↗
PubMed1991

Pseudophakic malignant glaucoma in a child.

We report a pseudophakic malignant glaucoma attack in the early postoperative period in the normal eye of an 8-year-old child who had undergone extracapsular cataract extraction with posterior chamber (modified Sinskey type) intraocular lens implantation for congenital zonular cataract. Intensive antiglaucoma medical therapy did not resolve the glaucoma, but vitreous aspiration and anterior chamber reformation proved successful.

Anterior Chamber↗
PubMed1991

Contrast sensitivity changes in background diabetic retinopathy.

Previous reports of contrast sensitivity in diabetic patients have shown conflicting results. We evaluated contrast sensitivity using Cambridge low-contrast sensitivity charts in 22 diabetic patients (22 eyes without retinopathy and 16 eyes with background retinopathy on fluorescein angiography) and 10 control subjects (20 eyes) matched for age and sex. The mean contrast threshold values at a spatial frequency of 4 cycles/degree were 0.46%, 0.60% and 0.43% in the three groups of eyes respectively. Contrast sensitivity was significantly lower in the diabetic eyes with retinopathy than in the normal eyes (p = 0.011) or the diabetic eyes without retinopathy (p = 0.033). This test may be of value in screening diabetic patients for retinopathy in primary care facilities.

Contrast Sensitivity↗
PubMed1991

Metastatic endophthalmitis: a reappraisal.

In view of the lack of studies of metastatic endophthalmitis and the controversies surrounding its management, we did a retrospective study of ten cases of metastatic endophthalmitis admitted to our center in 1987. A disproportionately high incidence of pediatric patients was found. The etiologic diagnosis was possible in eight of the ten cases. Bacterial infection was responsible in five of the eight cases where positive cultures were grown. Pseudomonas aeruginosa was the most common bacterial pathogen isolated. Most of the cases responded poorly to medical management. Seven of the ten patients finally underwent vitrectomy. Four of these seven cases had a postoperative visual acuity equal to or greater than 6/60 after vitrectomy. We believe that pars plana vitrectomy has a definite role in the management of metastatic endophthalmitis.

Adolescent↗
PubMed1990

Neuroblastoma in a patient with Sotos' syndrome.

Sotos' syndrome, or cerebral gigantism, is a disorder of growth regulation. Tumours have occasionally been reported in children with Sotos' syndrome, but it is uncertain whether this is a coincidence, or whether it is aetiologically related to the underlying disorder of growth. We report a 15 month old child with a paraspinal neuroblastoma and Sotos' syndrome and suggest that children with this condition may be at higher risk for developing tumours than the general population.

Facial Bones↗
PubMed1990

Endometrial response to deciduogenic stimulus in ovariectomized rhesus monkeys treated with oestrogen and progesterone: an ultrastructural study.

The present work continues our aim of establishing an experimental model to study the decidual cell reaction to an artificial deciduogenic stimulus in the long-term ovariectomized rhesus monkey treated with oestrogen followed by progesterone. The fine structural details of decidual, granular and plaque cells, which constituted the endometrial cellular response to the deciduogenic stimulation in the present study, revealed striking similarities with those reportedly present in an endometrial response to blastocyst implantation in the rhesus monkey. Plaque epithelia showed a significant degree of hypertrophy, hyperplasia and differentiation followed by a steady degeneration by day 32 (equivalent to day 16 after trauma) of treatment. The plaque cells were shown to contain numerous regular-shaped mitochondria, polyribosomes and large amounts of rough endoplasmic reticulum (RER) in their cytoplasm and were characteristically arranged in clusters or acini formation surrounded by discrete basal laminae. As early as day 28 of treatment, the initiation of stromal decidual cell transformation was noted and, by day 48, a sizeable pool of decidual cells was found. The decidual cells had rounded nuclei and elaborate arrangements of interconnected cisternae of RER which were often moderately dilated and filled with amorphous, electron-dense material. Granular cells were characterized by eccentrically located nuclei and numerous membrane-bound, electron-dense granules in their cytoplasm and were found in increasing numbers in the stroma around decidual cells, blood vessels and glandular epithelia.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

CAMFAK syndrome: a demyelinating inherited disease similar to Cockayne syndrome.

CAMFAK syndrome is an inherited disease characterized by congenital cataracts, microcephaly, failure to thrive, and kyphoscoliosis with onset in early infancy. Its pathogenesis has not been clearly defined. We report on a patient with this syndrome and present evidence that it is a neurologic disease characterized by peripheral and central demyelination similar to that seen in Cockayne syndrome.

Abnormalities, Multiple↗
PubMed1989

Is there any delta 5-3 beta hydroxysteroid dehydrogenase activity in preimplantation embryo of rhesus monkey?

This is the first report on the histochemical assessment of delta 5-3 beta hydroxysteroid dehydrogenase activity in all the preimplantation embryonic stages in the rhesus monkey (Macaca mulatta). An apparent stage dependent increase in enzyme activity was obtained, however, distinctively a high degree of non-specificity in enzyme reaction was noted primarily in morulae and blastocysts. Such marked non-specificity in the histochemical enzyme reaction for delta 5-3 beta hydroxysteroid dehydrogenase activity was not found in mouse blastocysts. High amounts of endogenous steroids present within rhesus embryos, or the participation of non-specific dehydrogenases could account for the observed non-specificity. Furthermore, the present report documents the pattern and degree of association (r = 0.9; P less than 0.01) between developmental stage and gestational age of preimplantation rhesus embryos, and thus provides a normal in situ cell cleavage rate of preimplantation embryo in the rhesus monkey.

3-Hydroxysteroid Dehydrogenases↗
PubMed1988

Endometrial phosphatases, beta-glucuronidase and cathepsin D during menstrual cycle and pre-implantation stages of gestation in the rhesus monkey (Macaca mulatta).

beta-glucuronidase, cathepsin D, acid and alkaline phosphatases were studied in rhesus monkey endometrium during the menstrual cycle (day -6 to day +10) and pre-implantation stages (day +3 to day +6) of gestation, with day 0 considered as the day of ovulation. Acid hydrolases exhibited low levels in proliferative phase endometria followed by their gradual rise in the secretory phase of the menstrual cycle. Despite no shifts in the levels of serum progesterone and estradiol-17 beta, the pre-implantation period was, however, associated with distinct changes in enzyme profiles characterized by lower absolute levels (P less than 0.05) of acid phosphatase and beta-glucuronidase on days 3 to 6 of gestation, whereas cathepsin D activity declined significantly (P less than 0.05) on days 5 and 6. Alkaline phosphatase showed a characteristic rise during the pre-ovulatory period with a gradual lowering of its level in post-ovulatory phase endometria of a non-fertile cycle; in contrast, during early gestation, alkaline phosphatase activity showed a marked elevation (P less than 0.05) on days 5 and 6 of gestation. The significance of these findings is discussed.

Acid Phosphatase↗
PubMed1988

Fetal glycaemic control and neonatal complications in diabetic pregnancy.

To examine the relationship between fetal glycaemic control and macrosomia or neonatal hypoglycaemia, we measured umbilical cord glycosylated haemoglobin (GHb) by affinity chromatography in 44 diabetic and 40 normal pregnancies. Levels of GHb in cord blood were not significantly different between these two groups, suggesting good maternal glycaemic control was achieved in the diabetic patients. Moreover in the diabetic pregnancies, cord GHb levels did not differ in infants who were macrosomic or developed hypoglycaemia by comparison with those infants who showed neither phenomenon. We conclude that overall fetal glycaemic control in the 4-6 week period prior to delivery does not appear to influence these common neonatal complications of diabetic pregnancy.

Adult↗
PubMed1987

The relative extent of glycation of haemoglobin and albumin.

The level of non-enzymatic glycation of a protein is thought to depend on the number of sites available for reaction, the half-life of the protein and the ambient concentration of glucose. Accordingly, the modification of two blood proteins with a similar number of potential sites but different survival times was examined in non-diabetic patients by periodate oxidation and by reduction with [3H]borohydride. The amount of glycation of haemoglobin and its sub-fractions HbA1 and HbA1c were determined to be 0.44, 2.42 and 2.24 mol/mol respectively and the corresponding value for albumin was 0.37 mol/mol protein. Amino acid analysis showed that the epsilon amino groups of albumin were more extensively modified than they were in haemoglobin and thus it is concluded that the average rate of reaction of the lysine residues in albumin is markedly faster than in haemoglobin.

Amino Acids↗
PubMed1987

Benzodiazepine receptor development in murine glial cultures.

Benzodiazepine (BDZ) receptor binding characteristics were determined from glial cultures prepared from the cerebral hemispheres of newborn mice. Receptor binding and saturation analyses were performed at various ages in culture on intact cells. Utilizing 5 nM 3H-diazepam at 0.4 degrees C, specific binding reached a plateau at 16-21 days after plating. A single high-affinity binding site was identified with Kd 25.3 +/- 2.6 nM and Bmax 7,575 +/- 410 fmol/mg protein. Inhibition studies utilizing clonazepam indicated that this ligand, thought to have affinity exclusively for neurons, displaces more than 20% of the specific BDZ binding at concentrations as low as 300 nM, although the IC50 was 1.5-2.0 microM. In contrast, the IC50 for Ro5-4864 was 10-20 nM.

Animals↗
PubMed1987

Peroxisomal disorders. A review of a recently recognized group of clinical entities.

The peroxisome is a small organelle present in almost all cells. The peroxisomal disorders are a newly recognized group of disease entities that share structural and/or functional abnormalities of the peroxisomes, are inherited, and may have profound neurologic and systemic effects. Some of the disorders lack peroxisomes in cells, while others have single or multiple peroxisomal enzymatic deficiencies despite the presence of normally appearing peroxisomes. The prototype of the peroxisomal disorders is Zellweger syndrome. X-linked adrenoleukodystrophy, neonatal adrenoleukodystrophy, infantile Refsum disease, hyperpipecolic acidemia and Refsum disease are some of the other disease entities presently classified as peroxisomal disorders. Accurate methods of pre- and postnatal diagnosis are available. Treatment strategies are being developed, but at this time prenatal diagnosis and appropriate genetic counseling is the best therapeutic intervention for those peroxisomal disorders characterized by profound neurologic handicap and early death.

Adrenoleukodystrophy↗