Role of tear anti-acanthamoeba IgA in Acanthamoeba keratitis.
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Acanthamoeba↗
Biomedical subjects
S Apte
Publications and source records attributed to S Apte.
Population genetic subdivision in the New Zealand greenshell mussel (Perna canaliculus) inferred from single-strand conformation polymorphism analysis of mitochondrial DNA.
Single-strand conformation polymorphism (SSCP) analysis of the NADH IV region of the mitochondrial DNA (mtDNA) molecule in greenshell mussels (Perna canaliculus) indicated strong population genetic structuring in this endemic New Zealand species. A northern and a southern group were differentiated by frequency shifts in common haplotypes and by the occurrence of a unique southern haplotype at approximately 20% frequency. This split occurred south of Cook Strait (the body of water between the North and the South Island) at approximately 42 degrees S latitude. Northern populations were less genetically diverse than southern populations and mussels from the west coast of the South Island were most distinct from northern mussels. We hypothesize that the unique haplotype VIII originated in the lower South Island, and that its spread northwards was obstructed by the opening of Cook Strait approximately 15 000-16 000 years ago and the subsequent establishment of present-day surface water circulation patterns in Greater Cook Strait. We suggest that present-day strong tidal flows and turbulent mixing of water masses in Cook Strait, and intense up-welling on the east and west coasts in this region, represent a barrier to gene flow between mussels located in the North Island and northern South Island vs. mussels in most of the South Island and Stewart Island.
Animals↗
LDL receptor-related protein 5 (LRP5) affects bone accrual and eye development.
In humans, low peak bone mass is a significant risk factor for osteoporosis. We report that LRP5, encoding the low-density lipoprotein receptor-related protein 5, affects bone mass accrual during growth. Mutations in LRP5 cause the autosomal recessive disorder osteoporosis-pseudoglioma syndrome (OPPG). We find that OPPG carriers have reduced bone mass when compared to age- and gender-matched controls. We demonstrate LRP5 expression by osteoblasts in situ and show that LRP5 can transduce Wnt signaling in vitro via the canonical pathway. We further show that a mutant-secreted form of LRP5 can reduce bone thickness in mouse calvarial explant cultures. These data indicate that Wnt-mediated signaling via LRP5 affects bone accrual during growth and is important for the establishment of peak bone mass.
Adaptor Proteins, Signal Transducing↗
Absence of population genetic differentiation in the New Zealand greenshell mussel Perna canaliculus (Gmelin 1791) as assessed by allozyme variation.
Genetic variation in the endemic New Zealand greenshell mussel, Perna canaliculus (Gmelin 1791), was examined using starch-gel electrophoresis at seven protein-coding loci (Idh; Acon-1; Acon-2; Gpd; Pgi; Pgm; Pgd) in 35 populations (N=1038 mussels). For all loci and all populations, Fisher's exact tests indicated highly significant departures from Hardy-Weinberg equilibrium (HWE), but this overall result was caused by significant heterozygote deficiencies at only two loci (Pgm and Pgd), and in only three northern populations (Kuaotunu, Te Haumi and Days Bay). Allelic and genotypic differentiation between population pairs at individual loci and across all loci were nonsignificant, and genotypic disequilibrium at each locus pair was also nonsignificant for all populations. Genetic variation in all populations was high (mean heterozygosity, 0.210+/-0.113), while Nei's D among populations was very low (0.002+/-0.002). Low population subdivision (θ=-0.001+/-0.002) and high levels of gene flow (Nm(p)=10.18; Nm(θ)=infinity) also indicated that the single panmictic unit model best explains population genetic homogeneity in P. canaliculus over a north-south distance >2000 km. Lack of genetic subdivision in this species is discussed in light of two previous allozyme studies, with differing results: one suggested that a north-south division exists between greenshell mussel stocks, and the other suggested that population structure in this species can be explained through isolation by distance model modified by local hydrology.
Journal Article↗
Three polymorphic mitochondrial DNA markers for Perna canaliculus.
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Animals↗
Tear IgA and serum IgG antibodies against Acanthamoeba in patients with Acanthamoeba keratitis.
PURPOSE: Exposure to Acanthamoebaspecies appears to be ubiquitous, as 50% to 100% of healthy human subjects display anti-Acanthamoebaantibodies. However, the presence of specific anti-Acanthamoebaantibodies in the serum and tears of patients has not been investigated. The prevalence of serum immunoglobulin G (IgG) and tear IgA against three species of Acanthamoebawas assessed in healthy subjects and patients with Acanthamoebakeratitis. METHODS: The level of specific serum IgG and tear IgA against A. castellanii, A. astronyxis, and A. culbertsoniin the sera of 23 patients and 25 healthy subjects was tested by enzyme-linked immunosorbent assays. Total serum IgM, IgG, and IgA concentrations were measured by nephelometry. Acanthamoebakeratitis was diagnosed clinically and confirmed by in vivo confocal microscopy. In some patients, corneal biopsies were also performed and trophozoites were cultured on lawns of Escherichia colion non-nutrient agar. RESULTS: All healthy subjects and patients with Acanthamoebakeratitis had detectable serum IgG antibodies against all Acanthamoebaantigens. However, patients with Acanthamoebakeratitis had significantly higher anti-AcanthamoebaIgG antibody titers than healthy subjects. In contrast, Acanthamoeba-specific tear IgA was significantly lower in patients with Acanthamoebakeratitis in comparison with healthy subjects. Total serum immunoglobulins did not differ significantly between healthy subjects and patients with Acanthamoebakeratitis. CONCLUSIONS: The results suggest that a low level of anti-AcanthamoebaIgA antibody in the tears appears to be associated with Acanthamoebakeratitis.
Acanthamoeba↗
Exacerbation of Acanthamoeba keratitis in animals treated with anti-macrophage inflammatory protein 2 or antineutrophil antibodies.
Neutrophils are thought to be involved in many infectious diseases and have been found in high numbers in the corneas of patients with Acanthamoeba keratitis. Using a Chinese hamster model of keratitis, conjunctival neutrophil migration was manipulated to determine the importance of neutrophils in this disease. Inhibition of neutrophil recruitment was achieved by subconjunctival injection with an antibody against macrophage inflammatory protein 2 (MIP-2), a powerful chemotactic factor for neutrophils which is secreted by the cornea. In other experiments, neutrophils were depleted by intraperitoneal injection of anti-Chinese hamster neutrophil antibody. The inhibition of neutrophils to the cornea resulted in an earlier onset and more severe infection compared to controls. Anti-MIP-2 antibody treatment produced an almost 35% reduction of myeloperoxidase activity in the cornea 6 days postinfection, while levels of endogenous MIP-2 secretion increased significantly. Recruitment of neutrophils into the cornea via intrastromal injections of recombinant MIP-2 generated an initially intense inflammation that resulted in the rapid resolution of the corneal infection. The profound exacerbation of Acanthamoeba keratitis seen when neutrophil migration was inhibited, combined with the rapid clearing of the disease in the presence of increased neutrophils, strongly suggests that neutrophils play an important role in combating Acanthamoeba infections in the cornea.
Acanthamoeba Keratitis↗
Human uveal melanoma cells produce macrophage migration-inhibitory factor to prevent lysis by NK cells.
Human uveal melanoma arises in an immune privileged ocular environment in which both adaptive and innate immune effector mechanisms are suppressed. Uveal melanoma is the most common intraocular tumor in adults and is derived from tissues in the eye that produce macrophage migration-inhibitory factor (MIF), a cytokine that has recently been demonstrated to produce immediate inhibition of NK cell-mediated lytic activity. Although NK cell-mediated lysis of uveal melanomas is inhibited in the eye, melanoma cells that disseminate from the eye are at risk for surveillance by NK cells. Moreover, uveal melanoma cells demonstrate a propensity to metastasize to the liver, an organ with one of the highest levels of NK activity in the body. Therefore, we speculated that uveal melanomas produced MIF as a means of escaping NK cell-mediated lysis. Accordingly, seven primary uveal melanoma cell lines and two cell lines derived from uveal melanoma metastases were examined for their production of MIF. MIF was detected in melanoma culture supernatants by both ELISA and the classical bioassay of macrophage migration inhibition. Melanoma-derived MIF inhibited NK cell-mediated lysis of YAC-1 and uveal melanoma cells. Cell lines derived from uveal melanoma metastases produced approximately twice as much biologically active MIF as cultures from primary uveal melanomas. Inhibition of NK cell-mediated killing by uveal melanoma-derived MIF was specifically inhibited in a dose-dependent manner by anti-MIF Ab. The results suggest that human uveal melanoma cells maintain a microenvironment of immune privilege by secreting active MIF that protects against NK cell-mediated killing.
Animals↗
Effect of tumor necrosis factor alpha and intercellular adhesion molecule-1 expression on immunogenicity of murine liver cells in mice.
Adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) have been implicated in the pathogenesis of various inflammatory liver disease states, including viral and autoimmune hepatitis as well as liver allograft rejection. Tumor necrosis factor alpha (TNF-alpha) is an inflammatory cytokine known to up-regulate adhesion molecules as well as major histocompatibility complex (MHC) class I expression, and has been demonstrated to be important in the rejection of vascularized organ allografts. The current studies address the effect of TNF-alpha and the role of ICAM-1 expression on liver cell immunogenicity in vitro in mixed lymphocyte hepatocyte culture (MLHC), in vitro in mixed lymphocyte liver nonparenchymal cell culture (MLNPC), in vivo in hepatocyte sponge matrix allografts (HC-SMA), and in vivo in liver nonparenchymal cell sponge matrix allografts (NPC-SMA). Purified allogeneic hepatocytes (HC) and liver nonparenchymal cells (NPC) under naive, unstimulated conditions demonstrated different profiles of MHC antigen and adhesion molecule expression, but both liver cell populations stimulated the proliferation and development of allospecific cytotoxic effectors in vitro and in vivo. Despite significant up-regulation of MHC class I and ICAM-1 on both HC and liver NPCs by in vivo treatment with TNF-alpha, the immunogenicity of TNF-alpha-stimulated liver cells was not appreciably different from naive, unstimulated liver cells. In contrast, ICAM-1-negative HC and NPCs were significantly less immunogenic both in terms of lymphocyte proliferative responses and the generation of allospecific cytolytic effectors. These results suggest that constitutive expression of ICAM-1 enhances the immunogenicity of "donor" liver cells but is not absolutely required to elicit immune responses to allogeneic liver cells. Further studies to determine the role of adhesion molecule expression on trafficking of host immune cells to the liver and the role of adhesion molecule expression by host cells are required to clarify their role in immune responses to liver cells.
Animals↗
Identification and characterization of a novel human matrix metalloproteinase with unique structural characteristics, chromosomal location, and tissue distribution.
We have cloned a novel member of the matrix metalloproteinase (MMP) family of proteins from a human liver cDNA library. The isolated cDNA contains an open reading frame coding for a polypeptide of 508 amino acids, which has been tentatively called MMP-19. This protein exhibits the domain structure characteristic of previously described MMPs, including a signal sequence, a prodomain with the cysteine residue essential for maintaining the latency of these enzymes, an activation locus with the zinc-binding site, and a COOH-terminal fragment with sequence similarity to hemopexin. However, it lacks a series of structural features distinctive of the diverse MMP subclasses, including the Asp, Tyr, and Gly residues located close to the zinc-binding site in collagenases, the fibronectin-like domain of gelatinases, the transmembrane domain of membrane-type (MT) MMPs, and the furin-activation sequence common to stromelysin-3 and MT-MMPs. In addition, the 9-residue insertion rich in hydrophobic amino acids present at the hinge region in stromelysins is replaced in MMP-19 by a longer insertion very rich in acidic residues. On the basis of these structural characteristics, we propose that MMP-19 does not belong to any of the previously defined MMP-subclasses and may represent the first member of a new MMP subfamily. Chromosomal location of the MMP-19 gene revealed that it maps to chromosome 12q14, which is also a unique location for any MMPs mapped to date. The cDNA encoding a full-length MMP-19 was expressed in Escherichia coli, and after purification and refolding, the recombinant protein was able to degrade synthetic substrates for MMPs. MMP-19 proteolytic activity was abolished by TIMP-2 and EDTA, thus providing additional evidence that the isolated cDNA codes for an authentic MMP. Northern blot analysis of polyadenylated RNAs isolated from a variety of human tissues revealed that MMP-19 is mainly expressed in placenta, lung, pancreas, ovary, spleen, and intestine, suggesting that it may play a specialized role in these tissues.
Amino Acid Sequence↗
Percutaneous management of urolithiasis during pregnancy.
A total of 6 pregnant women with obstructing urinary calculi was managed by percutaneous nephrostomy drainage placed under ultrasound guidance with the patient under local anesthesia. All patients initially had relief of acute obstruction. However, occlusion of the percutaneous nephrostomy tubes with debris necessitated tube changes in 5 of 6 patients. In 2 patients recurrent nephrostomy tube obstruction, fever and pain led to percutaneous stone removal during pregnancy. In the remaining 4 patients the nephrostomy tubes were left indwelling through delivery. During the postpartum period 3 patients successfully underwent ureteroscopic stone extraction and 1 passed the stone spontaneously. Bacteriuria developed in each patient despite the use of preventive antibiotics. All 6 women had uncomplicated vaginal deliveries of healthy newborns and are currently asymptomatic with no evidence of obstruction. Percutaneous drainage of an acutely obstructed kidney in a pregnant woman is an effective temporizing alternative to ureteral stent placement until definitive treatment can be performed.
Adolescent↗
A double balloon occlusion technique for embolectomy in the trifurcation vessels.
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Catheterization↗
Cloning of human alpha 1(X) collagen DNA and localization of the COL10A1 gene to the q21-q22 region of human chromosome 6.
With consensus primers based upon the nucleotide sequence of the chicken alpha 1(X) collagen gene, we have used PCR with human genomic DNA as template to isolate a 289 bp fragment coding for part of the carboxyl non-triple helical domain of the human alpha 1(X) gene. We have demonstrated the presence of the sequence of the PCR clone within the human genome by partial sequence analysis of a 1 kb HindIII genomic DNA fragment that hybridized with the PCR clone. Furthermore, using the PCR clone as a probe for in situ hybridization of human metaphase chromosome spreads, and for Southern analysis of a panel of human-hamster somatic cell hybrid DNAs, we have assigned the locus for the alpha 1(X) gene to the q21-q22 region of human chromosome 6.
Amino Acid Sequence↗
The alpha 2(VIII) collagen gene. A novel member of the short chain collagen family located on the human chromosome 1.
Type VIII collagen is a major component of Descemet's membrane, the specialized basement membrane of corneal endothelial cells. Sequence analysis of a cDNA isolated from a library made with mRNA from rabbit corneal endothelial cells has indicated that type VIII molecules contain a polypeptide chain, alpha 1(VIII), consisting of a short triple-helical domain of 454 amino acid residues flanked by non-triple-helical domains of 117 and 173 amino acid residues at the amino and carboxyl ends, respectively (Yamaguchi, N., Benya, P. D., van der Rest, M., and Ninomiya, Y. (1989) J. Biol. Chem. 264, 16022-16029). The sequence of alpha 1(VIII) is strikingly similar to that of alpha 1(X) collagen, a product of hypertrophic chondrocytes. Also, characterization of the alpha 1(VIII) and alpha 1(X) collagen genes has shown that they are quite similar in their exon organization. It has been concluded, therefore, that they are homologous members of a distinct subclass of collagen genes (Yamaguchi, N., Mayne, R., and Ninomiya, Y. (1991) J. Biol. Chem. 266, 4508-4513). We have given this subclass the name short chain collagens because of the relatively small size of the triple-helical domain. In the present study, we report on the identification and characterization of a collagen gene encoding a polypeptide which is co-expressed with the alpha 1(VIII) chain in corneal endothelial cells. This collagen chain contains a triple-helical and a carboxyl non-triple-helical domain encoded by a single, large exon both in mice and humans. We conclude, therefore, that the genes encodes a novel member of the short chain collagen family, and we have given this chain the designation alpha 2(VIII) collagen. By in situ hybridization we demonstrate that the alpha 2(VIII) gene is located in the p32.3-p34.3 region of the short arm of chromosome 1.
Amino Acid Sequence↗
Multiple fractures of the silver wire strands as a complication of the silicone-silver wire prosthesis.
A review of 5 consecutive cases in which removal of the silicone-silver wire prosthesis was necessary within 2 years of implantation has revealed multiple breaks in all strands of the silver wire core in both of the paired cylinders.
Adult↗
The influence of manufacturing parameters on the formation and growth on autoclaving of a 40% V/V Bis-Perfluorobutylethene emulsion.
The influence of different process variables on the number of large particles before and after autoclaving of a 40% V/V Bis-Perfluorobutylethene emulsion stabilized by egg yolk lecithin, made isotonic with blood, was examined. The concentration of emulsifier, emulsification and autoclaving time and temperature, fill volume and the cooling gradient applied to the emulsion after autoclaving all affect the number of large droplets and hence the stability and acceptability of the finished product. This work suggests that validation of equipment and process to very exacting specifications and strict adherence to specified manufacturing protocol is essential for the reproducible production of fluorocarbon emulsions acceptable for intravenous administration.
Emulsions↗
Surgery in patients with congenital coagulation disorders.
BACKGROUND: Surgery is occasionally necessary in patients with congenital coagulation disorders. Major surgery for patients with haemophilia was not being done in India until recently. This paper reports the experience of a single referral centre. METHODS: The data of 52 patients who were operated upon were collected from the hospital records retrospectively between 1984 and 1986 and prospectively thereafter. They included the surgical procedure performed, replacement therapy used and complications encountered. RESULTS: Fifty-nine procedures were performed of which 26 were major, 30 minor and 3 were diagnostic angiograms. Blood components produced in the hospital blood bank were commonly used for replacement and primary haemostasis was achieved in all patients. Delayed bleeding due to inadequate factor levels occurred in 12 procedures and was controlled by increasing the factor replacement. One patient died of suspected acute myocardial ischaemia. CONCLUSION: In India surgical procedures can be safely performed in patients with congenital coagulation disorders.
Adolescent↗