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Biomedical subjects

R Anand

Publications and source records attributed to R Anand.

At least 127 records · Page 7Linked to original sources
PubMed1993

Control of cytomegalovirus retinitis using sustained release of intraocular ganciclovir.

An experimental intravitreal sustained-release device containing ganciclovir was used to treat 22 patients with acquired immunodeficiency syndrome-associated cytomegalovirus retinitis. Fourteen eyes were excluded (five not involved and nine with macular scarring and/or severe debility). Thirty eyes received the ganciclovir intraocular device implant and were prospectively followed up from 16 to 419 days (median, 125 days). Twenty-seven (90%) of 30 eyes showed stabilization of the retinitis. Nine (33%) of 27 eyes showed reactivation of the retinitis once the device was empty of ganciclovir; seven received a replacement device, with subsequent stabilization of the retinitis. Postoperative complications included vitreous hemorrhage (n = 1), endophthalmitis (n = 1), and progressive retinitis (n = 2). Late retinal detachment was seen in three eyes (11%) at 35 to 140 days. Survival analysis of all 30 eyes revealed the mean time to progression of retinitis to be 19 weeks (133 days). The ganciclovir intraocular device offers a promising alternative for the treatment of cytomegalovirus retinitis associated with acquired immunodeficiency syndrome.

AIDS-Related Opportunistic Infections↗
PubMed1993

Generation of ordered phage sublibraries of YAC clones: construction of a 400-kb phage contig in the human dystrophin gene.

A phage contig of 400 kb that extends from the brain-specific promoter at the 5'-end of the human dystrophin gene, through the muscle-specific promoter over 100 kb further downstream, and across most of intron 1 has been assembled. To achieve this, a yeast artificial chromosome (YAC) subcloning approach was used. Total DNA from a yeast strain containing a 400-kb YAC from the dystrophin gene was cloned using a lambda phage vector containing RNA polymerase promoters flanking the cloning sites. Phage containing human DNA inserts were then ordered into an overlapping set by hybridization of end-specific RNA probes from individual clones back to plaque lifts of gridded phage subclones. The clones generated will be useful as reagents for detailed structural and functional analyses of this region of the dystrophin gene.

Bacteriophages↗
PubMed1993

Restriction fragment length polymorphism and evolution of the mouse immunoglobulin constant region gamma loci.

Genomic DNA from twelve laboratory mouse strains, in addition to 21 wild-derived strains belonging to different taxa (Mus musculus domesticus, Mus musculus musculus, Mus spretus, Mus macedonicus, and Mus spicilegus) and four mouse strains that are evolutionarily more distant, were analyzed by Southern blot for polymorphism of the Ig heavy chain constant region gamma isotype (Igh-C gamma) and for the distribution of the duplicated Igh-1 (C gamma 2 alpha) haplotype. Distinct allelic forms of each Igh-C locus could be defined by restriction fragment length polymorphism (RFLP). In laboratory mouse strains RFLP proved to be more sensitive in the detection of Igh-4 (C gamma 1) alleles than serological methods. Taq I digestion allowed the definition of two alleles in the Igh-8 (C gamma 3) locus, which is absolutely conserved at the protein levels. More extensive RFLP could be found in wild strains belonging to the subgenus Mus and in the evolutionarily more distant Mus species belonging to other subgenera. In previous studies we have shown that the Igh-1 locus is duplicated in M. m. musculus subspecies. We now extend this observations to the wild mouse strains belonging to M. spicilegus and M. macedonicus species and to the evolutionarily more distant wild mouse strain Mus pahari (subgenus coelomys), which is thought to have diverged from domestic mice about 5 million years ago. In addition, we found a similar RFLP pattern in ten of 18 wild mice trapped in India, suggesting that the haplotype containing the two Igh-1-like genes, organized in tandem as distinct isotypes, is widely spread in natural populations. The evolution of murine Igh-C gamma-encoded isotypes is also discussed.

Animals↗
PubMed1993

A physical map of the human APP gene in YACs.

Several point mutations within exons 16 and 17 of the amyloid precursor protein (APP) gene have been reported that are associated with Alzheimer's disease in a small number of familial cases. To determine the size of the APP gene and the organization of the exons within human genomic DNA, we have characterized 11 Yeast Artificial Chromosome (YAC) recombinants containing human APP gene sequences. The smallest YAC insert was 125 kb, and the largest was 1.4 Mb. The YACs were screened by polymerase chain reaction amplification of APP exons to determine which of the 18 exons coding for APP770 were present. Four of the YACs (D110G1, D110G6, D110E9, and B142F9) contain all 18 exons and at least part of the promoter. Construction of an overlapping map of the gene with all of the YACs demonstrated that 3 of the 11 YACs were chimeric. The orientation and position of the coding sequence on the map was determined by probing digests of the YAC DNA with exon PCR products and the vector arms. The coding region of the APP gene spans approximately 400 kb of genomic DNA.

Amyloid beta-Protein Precursor↗
PubMed1993

Pathology of cytomegalovirus retinitis treated with sustained release intravitreal ganciclovir.

BACKGROUND: An experimental sustained release intraocular device has been designed to deliver ganciclovir over a long period of time. As part of an efficacy trial, the ganciclovir intraocular device was used to treat cytomegalovirus (CMV) retinitis in patients with acquired immune deficiency syndrome (AIDS). METHODS: All patients had active CMV retinitis that had progressed despite intravenous ganciclovir therapy. The ganciclovir intraocular device was inserted into the vitreous cavity by making an inferotemporal full-thickness circumferential sclerotomy and anchored to the incision. Intravenous therapy was then discontinued and patients were followed up at 2-week intervals until death. Seven eyes from five patients were obtained 2 to 10 hours postmortem and submitted for histopathologic examination. Light and electron microscopic studies were performed and correlated to the clinical outcome. Follow-up period after device placement ranged from 16 to 82 days (median, 70 days). RESULTS: All seven eyes showed clinical stabilization of the CMV retinitis. Light microscopy showed varying degrees of retinal atrophy with areas of gliosis. In addition, we observed syncytial megalic cells containing Cowdrey type A inclusions affecting all layers of the retina. Concurrent choroidal infections with Pneumocystis carinii (1) and Mycobacterium avium (2) also were seen. Electron microscopy showed virus particles located mostly at the junction of uninvolved and "healed" retinitis. No evidence of retinal toxic effects or inflammation at the site of ganciclovir intraocular device implant was noted. CONCLUSION: The ganciclovir intraocular device appeared to be effective in controlling the progression of CMV retinitis. The clinical and pathologic results are similar to those observed in the eyes of patients with intravenously administered ganciclovir. The lack of toxic effects and sustained levels of intravitreal ganciclovir may provide an improved therapeutic method of local treatment of CMV retinitis.

AIDS-Related Opportunistic Infections↗
PubMed1993

Structure and physical map of 64 variable segments in the 3'0.8-megabase region of the human immunoglobulin heavy-chain locus.

We have constructed the physical map of the 0.8 megabase DNA fragment which contains the 3' 64 variable region (V) gene segments of the human immunoglobulin heavy chain (H) locus. The organization of the VH locus showed several features that indicate dynamic reshuffling of this locus. The sequenced 64 VH segments include 31 pseudogenes, of which 24 are highly conserved except for a few point mutations. Comparison of the 64 germline VH sequences shows that each VH family has conserved sequences, suggesting that there might be some genetic or selection mechanisms involved in maintenance of each family. The total number of the human VH segments was estimated to be about 120, including at least 7 orphons.

Amino Acid Sequence↗
PubMed1993

Pseudohypopyon in unilateral acute idiopathic maculopathy.

Unilateral acute idiopathic maculopathy (UAIM) is a recently described condition in young adults consisting of rapidly progressive central visual loss, gray-white opacification of the outer retina, and serous detachment of the macula. Bull's eye pattern pigmentary changes may occur in the macula after resolution of the acute phase of the disease. A case of UAIM in which a shifting of subretinal inflammatory infiltrate was observed is reported. This is the tenth reported case of UAIM, and represents a variation in the clinical presentation of this disease. The appearance and the shifting of the subretinal infiltrate seen in this patient support an inflammatory etiology of UAIM.

Acute Disease↗
PubMed1993

Effect of anti-ganglioside antibodies on the metastatic spread of intraocular melanomas in a nude mouse model of human uveal melanoma.

In vivo and in vitro studies were performed to determine: (a) if human uveal melanoma cells expressed GD2 and GD3 gangliosides; (b) if anti-GD2 monoclonal antibodies would inhibit the propensity of human uveal melanoma cells to localize in the liver following intravenous injection; and (c) if anti-GD2 monoclonal antibody would reduce the spontaneous metastasis of primary intraocular melanomas in nude mice. The results showed that all three of the human uveal melanoma cell lines tested expressed GD2 and GD3 gangliosides in vitro and in vivo. The human uveal melanoma cell lines preferentially localized in the liver and entered the hepatic parenchyma following spontaneous metastasis from the eyes of nude mice. In vivo administration of anti-GD2 monoclonal antibody produced a sharp reduction in the number of uveal melanoma cells that disseminated to the liver following either intravenous injection or by spontaneous metastasis from primary intraocular melanomas. Collectively, the results demonstrate that uveal melanoma cells display a propensity to localize in the liver after entering the bloodstream; however, this localization can be significantly inhibited by in vivo administration of anti-ganglioside antibodies. The expression of GD2 and GD3 surface gangliosides on uveal melanomas and the capacity of anti-ganglioside antibodies to inhibit metastasis formation in mouse models of ocular and cutaneous melanomas raise the possibility of implementing anti-ganglioside antibodies as potential therapeutic agents for the management of uveal melanoma.

Animals↗
PubMed1993

Localisation of pp60c-src to the surface membrane of human platelets.

In platelets, pp60c-src has been variously localised to cytosol, dense bodies, or plasma membrane and surface-connected canalicular membranes. We have investigated the localisation of pp60c-src in highly purified human platelet subcellular fractions isolated using density gradient centrifugation and continuous flow electrophoresis followed by quantitative immunoblotting. We have obtained fractions enriched in surface membranes and alpha granule membranes as assessed by the presence of the marker proteins gpIb, gpIIb, thrombospondin, fibrinogen and fibronectin. Quantitative immunoblotting demonstrated that most of the cellular pp60c-src co-purified with markers for surface membrane components and that unlike the situation in fibroblasts, platelet pp60c-src did not associate with non-granule intracellular membranes such as Golgi, endoplasmic reticulum and endosomes. A small subpopulation of the total cellular pp60c-src co-purified with granule components or dense body markers, however this occurred in proportion to the presence of surface membrane markers. Our results demonstrate that the majority of platelet pp60c-src is located on the cytoplasmic face of the plasma membrane in human platelets.

Blood Platelets↗
PubMed1993

The interaction of the tyrosine kinase pp60src with membrane and cytoskeletal components.

To study the mechanism of oncogenic transformation we have investigated the association of pp60v-src with the cytoskeleton using a variety of mutants. Transformation is associated with the interaction of pp60v-src with the cytoskeleton, specifically in adhesion plaques. Biochemical analysis has shown a correlation between tyrosine-specific phosphorylation of the fibronectin receptor and the loss of surface-bound fibronectin, but no such correlation with phosphorylation of vinculin or talin. The role of the nontransforming protooncogene product pp60c-src was studied in platelets, which express large amounts of this protein. In resting platelets pp60c-src was soluble in detergent-containing buffers, however it became associated with the cytoskeleton, but not the membrane skeleton, after platelet activation. This association was inhibited by EDTA or RGDS peptides and was therefore dependent on occupancy of a platelet integrin, gpIIb/IIIa. The role of pp60c-src-associated tyrosine phosphorylation in platelet activation was also investigated. Inhibitors of tyrosine phosphorylation inhibited integrin-dependent platelet aggregation and second messenger production, indicating a close linkage between matrix receptor occupancy, pp60c-src association with the cytoskeleton and platelet function.

Animals↗
PubMed1993

Pharmacological characterization of alpha-bungarotoxin-sensitive acetylcholine receptors immunoisolated from chick retina: contrasting properties of alpha 7 and alpha 8 subunit-containing subtypes.

At least three subtypes of alpha-bungarotoxin-sensitive acetylcholine receptors (alpha Bgt-sensitive AChRs) exist in chick brain and retina. All may contain previously unknown structural subunits. One subtype contains alpha 7 subunits. Another contains alpha 8 subunits. A third contains both alpha 7 and alpha 8 subunits. In this article, we describe, for the first time, the pharmacological characterization of alpha 7 AChRs and alpha 8 AChRs immunoisolated from chick retina. Pharmacologically, the alpha 8 AChRs exhibit two classes of binding sites, the high affinity of which have higher affinity for most cholinergic ligands than do alpha 7 AChRs. These differences are most accentuated for ACh (approximately 5400-fold), decamethonium (approximately 1400-fold), 1,1,-dimethyl-4 phenylpiperazinium (approximately 200-fold), atropine (approximately 200-fold), nicotine (approximately 100-fold), and tetramethylammonium (approximately 100-fold). The alpha 8 AChR low affinity sites exhibit affinities that are similar but not identical to that of alpha 7 AChRs. Many of the pharmacological differences between the alpha 7 AChRs and alpha 8 AChRs can be attributed to the limited differences between the amino acid sequences of the N-terminal region of the alpha 7 and alpha 8 subunits because expressed alpha 7 homomers and alpha 8 homomers also exhibit these characteristic differences.

Animals↗
PubMed1992

Targeted integration of neomycin into yeast artificial chromosomes (YACs) for transfection into mammalian cells.

Vectors have been constructed for the introduction of the neomycin resistance gene (neo) into the left arm, right arm or human insert DNA of yeast artificial chromosomes (YACs) by homologous recombination. These vectors contain a yeast selectable marker Lys-2, i.e. the alpha-aminoadipidate reductase gene, and a mammalian selection marker, neo, which confers G418 resistance. The vectors can be used to modify YACs in the most commonly used yeast strain for YAC library construction, AB1380. Specific targeting can be carried out by transfection of restriction endonuclease treated linear plasmids, with highly specific recombinogenic ends, into the YAC containing yeast cells. Analysis of targeted YACs confirmed that all three vectors can target correctly in yeast. Introduction of one of the targeted YACs into V79 (Chinese hamster fibroblast) cells showed complete and intact transfer of the YAC.

Animals↗
PubMed1992

Sustained-release ganciclovir therapy for treatment of cytomegalovirus retinitis. Use of an intravitreal device.

A surgically implantable device for sustained intravitreal release of ganciclovir has been developed. The device delivers ganciclovir intraocularly over approximately 4 to 5 months. Eight patients with acquired immunodeficiency syndrome (AIDS) and associated cytomegalovirus (CMV) retinitis were recruited as part of a phase 1 study. Thirteen eyes with active CMV retinitis underwent surgical implantation of the ganciclovir device. All eyes showed resolution of the CMV retinitis; none showed progression. Visual acuity remained unchanged in three eyes, improved in six eyes, and decreased in four eyes. Surgical complications included mild vitreous hemorrhage, astigmatism, and suprachoroidal placement of the device. Retinal detachment occurred in three eyes as the retinitis resolved. This new intraocular drug delivery system offers many advantages compared with intravenous therapy or repeated intravitreal ganciclovir injections for the management of CMV retinitis in patients with AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1992

The usefulness of echocardiography in the surgical management of infants with congenital heart disease.

Between January 1988 and August 1991, at The Children's Heart Center, Atlanta, 83 infants with congenital heart defects were diagnosed by echocardiography and underwent surgery without cardiac catheterization. The diagnostic categories included 46 infants with left heart obstructive lesions, 19 infants with cyanotic heart lesions, and 18 infants with miscellaneous lesions. Forty-five infants (55%) underwent surgery under cardiopulmonary bypass. There were three errors in diagnosis, yielding a diagnostic accuracy of 95%. Many infants with congenital heart disease can be accurately and completely diagnosed by echocardiography and can safely undergo surgery without cardiac catheterization.

Aortic Coarctation↗
PubMed1992

Molecular cloning and analysis of chromosome band 11q23 involved in leukaemia-associated translocations.

Three overlapping yeast artificial chromosomes (YACs) spanning a 780 kb region of DNA around the CD3 locus on chromosome 11 have been isolated and characterised. The individual cloned regions have been mapped by in situ hybridisation to chromosome band 11q23, and a restriction enzyme map of this region has been constructed. The positions of these clones in relation to a series of leukaemia-associated chromosomal translocations has also been determined. It was concluded that, although two clones lay entirely proximal to the breakpoints examined, the third clone (13HH4) encompassed the breakpoints for the translocations t(4;11), t(6;11), and t(9;11). The t(9;11) was observed in an acute myeloid leukaemia in a patient previously treated for an unrelated malignancy. It would thus appear that the breakpoints at chromosome band 11q23 occurring in therapy-related leukaemias are in the same region as those found in adult and childhood acute leukaemias and may result from a common underlying mechanism.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1992

Chromosomal localization of seven neuronal nicotinic acetylcholine receptor subunit genes in humans.

We have determined the chromosomal location of seven human neuronal nicotinic acetylcholine receptor subunit genes by genomic Southern analysis of hamster/human somatic cell hybrid DNAs. The beta 2 subunit gene was localized to human chromosome 1, the alpha 2 and beta 3 subunit genes were localized to human chromosome 8, the alpha 3, alpha 5, and beta 4 subunit genes were localized to human chromosome 15, and the alpha 4 subunit gene was localized to human chromosome 20. Mapping of the beta 2 subunit gene to chromosome 1 establishes a syntenic group with the amylase gene locus on human chromosome 1 and mouse chromosome 3, while mapping of the alpha 3 subunit gene to chromosome 15 confirms the existence of a syntenic group with the mannose phosphate isomerase gene locus on human chromosome 15 and mouse chromosome 9.

Animals↗