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Biomedical subjects

J Chodosh

Publications and source records attributed to J Chodosh.

At least 19 recordsLinked to original sources
PubMed1998

Anatomy of mammalian conjunctival lymphoepithelium.

Ocular surface immune mechanisms are subservient to the fine function of the eye. A clear cornea with a smooth, well-lubricated facade is prerequisite to lucid vision. Hence, corneal inflammation and post-inflammatory scarring are intolerable, and the cornea contains a minimum of lymphoid elements. Although conjunctival dysfunction and consequent tear film deficiency can malign the corneal surface, conjunctival inflammation is tolerated to a considerable degree. In contrast to the human cornea, human conjunctiva contains an abundance of lymphoid tissue. Certain aspects of human conjunctival immunology elicit little debate. Langerhans cells are abundant in conjunctival epithelium. Isolated CD8+ suppressor/cytotoxic T cells predominate in conjunctival epithelium, while T cells in the substantia propria distribute equally between CD4+ T helper cells and CD8+ cells. Yet the presence of plasma cells in human conjunctiva, the expression of secretory component by human conjunctival epithelium, and the function of human conjunctival lymphoid follicles are in dispute. Confusion may derive in part from the use of inappropriate animal models; rodent conjunctiva does not appear to be a worthy facsimile for human conjunctiva. Discrepancies between different human studies likely result from variance in subject age, biopsy site and extent, histologic or histochemical technique, and perhaps the degree of inflammation present at the time of biopsy. Careful immunohistochemical and in situ molecular assays on well-defined loci within the conjunctiva of comparable human subjects may resolve such questions in the future. Organized mucosa-associated lymphoid tissue is rigorously defined as mucosal lymphoid follicles with an ultrastructurally distinct overlying lymphoepithelium. Based on available evidence, the epithelium overlying mammalian conjunctival lymphoid follicles does not contain distinct M cells. Whether zonal differences in morphology reflect real differences in the capacity to sample tear film antigens for presentation to the mucosal immune system remains to be established.

Animals↗
PubMed1998

Photorefractive keratectomy for myopia in the setting of adenoviral subepithelial infiltrates.

PURPOSE: To report a patient with persistent subepithelial corneal opacities 18 months after adenoviral keratoconjunctivitis who underwent photorefractive keratectomy for the correction of myopia. METHODS: Case report, review of medical literature, and slit-lamp photography. RESULTS: The patient underwent photorefractive keratectomy in each eye, 1 week apart, with ablation of central corneal opacities and resultant best-corrected visual acuity of BE, 20/20. Symptomatic subepithelial stromal infiltrates recurred in the peripheral but not the central cornea of each eye 3 months after laser treatment. CONCLUSIONS: Photorefractive keratectomy was successful in the correction of myopia and prevented the recurrence of adenoviral subepithelial corneal infiltrates within the laser-treated central cornea.

Adenovirus Infections, Human↗
PubMed1998

Postoperative Rhizopus scleritis in a diabetic man.

A 50-year-old diabetic man developed necrotizing scleritis with adjacent keratitis 4 weeks after uncomplicated cataract extraction and intraocular lens implantation through a scleral tunnel incision. Cultures of the necrotic sclera grew Rizopus species. Severe destruction of the globe ensued despite topical, subconjunctival, and intravenous amphotericin B, in combination with hyperbaric oxygen therapy. Histopathological examination of the enucleated globe was consistent with Rhizopus infection. One year later, the patient was well without signs of recurrence.

Antifungal Agents↗
PubMed1998

Eradication of latent Epstein-Barr virus by hydroxyurea alters the growth-transformed cell phenotype.

The hallmark of infection by human herpesviruses, life-long persistence in the host, is unaffected by current antiviral therapies effective against replication of virus. In vitro studies indicated that low concentrations of the ribonucleotide reductase inhibitor, hydroxyurea, completely eliminated Epstein-Barr virus (EBV) episomes from latently infected Burkitt's lymphoma (BL) cell subsets, providing the first example of chemotherapeutic eradication of a latent herpesvirus from any cell population. Unlike parental EBV-positive BL cells, virus-free cell progeny from one treated cell line no longer exhibited the malignant phenotype in tumorigenicity assays. Hydroxyurea-treated primary B lymphocytes immortalized by EBV ceased to proliferate as episomes were lost. The altered growth phenotype of both BL cells and immortalized primary B cells suggests that latent EBV is an appropriate and accessible therapeutic target for treatment of some EBV-induced lymphoproliferations.

Animals↗
PubMed1998

Molecular epidemiology of Staphylococcus aureus and Enterococcus faecalis in endophthalmitis.

Genomic DNA fingerprint analysis was performed on 39 Staphylococcus aureus and 28 Enterococcus faecalis endophthalmitis isolates collected from multiple clinical centers. Among 21 S. aureus genomic DNA fingerprint patterns identified, five clonotypes were recovered from multiple unrelated patients and accounted for 58.9% (23 of 39) of the isolates analyzed. Compared with strains having unique genomic DNA fingerprint patterns, the S. aureus clonotypes occurring more than once were more likely to result in visual acuities of 20/200 or worse (P = 0.036 [chi2 test]). In contrast to the S. aureus isolates, the E. faecalis endophthalmitis isolates were a clonally diverse population, enriched for the expression of a known toxin, cytolysin, which is plasmid encoded.

Bacterial Typing Techniques↗
PubMed1997

Purification and characterization of secretory IgA from baboon colostrum.

In this report, we describe a method for purifying secretory immunoglobulin A (sIgA) from baboon (Papio anubis) colostrum. The colostrum was first clarified by centrifugation and then analyzed with various anti-human Ig-specific immunologic reagents. Cross-reactive IgA in the baboon colostrum was identified by ELISA. Western blot analysis also demonstrated cross-reactive epitopes associated with human IgA1, IgA2, secretory component (SC), and joining (J) chain. To purify the sIgA, colostrum was separated into 4 distinct fractions by gel filtration chromatography. Analysis of the individual fractions by ELISA indicated that the IgA elutes over one peak. The IgA fraction was compared with purified human sIgA on SDS-PAGE, and exhibited heavy (H) chains, light (L) chains, SC, and J chain. The baboon colostrum was also analyzed by ELISA for specific IgG H and L chain epitopes utilizing monoclonal antibodies (MAbs). No significant quantity of IgG was detected in the baboon colostrum or in the individual 4 fractions, while L chain reactivity was observed in the sIgA fraction. The sIgA fraction was pooled, concentrated, and was found to contain approximately 7 mg/ml sIgA. To determine if the baboon sIgA was dimeric like human sIgA, the purified sIgA was sized by molecular sieve chromatography. The molecular size of the sIgA preparation (350 kDa) was determined empirically by comparison to known molecular species used to calibrate the column. In addition, native SDS-PAGE indicated that baboon sIgA, like human sIgA, migrates between IgG and IgM, suggesting it has a dimeric form. The purified baboon sIgA preparation should prove useful in the future study of mucosal immune responses induced in non-human primate species and for the generation of sIgA-specific immunological reagents.

Animals↗
PubMed1997

Acanthamoeba infection after radial keratotomy.

PURPOSE: To describe a case of Acanthamoeba infection of the cornea after radial and astigmatic keratotomy. METHODS: A 29-year-old man developed ulcerative keratitis in the right eye 6 weeks after uncomplicated radial and astigmatic keratotomy. RESULTS: Three sets of corneal cultures for bacteria and fungi were negative. Culture on non-nutrient agar grew Acanthamoeba organisms. Clinical improvement occurred after topical antiamebic therapy was instituted. CONCLUSIONS: Incisional keratotomy may predispose the cornea to delayed-onset infectious keratitis. Acanthamoeba should be considered as a possible cause of infection and should be cultured for in refractory cases.

Acanthamoeba↗
PubMed1997

Epithelial cell polarization is a determinant in the infectious outcome of immunoglobulin A-mediated entry by Epstein-Barr virus.

Diseases of the nasopharyngeal epithelium due to Epstein-Barr virus (EBV) infection typically occur in chronic virus carriers with preexisting virus-specific antibodies. In vitro studies have shown that EBV-specific immunoglobulin A (IgA) promotes infection of human epithelial cells, otherwise refractory to EBV, via the polymeric immunoglobulin receptor (pIgR). To determine if EBV similarly exploits IgA transport mechanisms in vivo, we examined the fate of IgA-EBV complexes in the blood of mice, where pIgR-mediated transcytosis of IgA immune complexes through hepatocytes eliminates exogenous antigens from the circulation. By PCR analysis we showed hepatobiliary transport of IgA-EBV in viremic mice, but without detectable hepatocellular infection by immunostaining. Because efficient transport of EBV immune complexes might avert an infectious outcome, we modulated the transcytotic pathway in polarized Madin-Darby canine kidney (MDCK) cells transfected with pIgR to determine the effect on viral antigen expression. Like hepatocytes in vivo, MDCK cells in polarized monolayers translocated IgA-EBV from the basal cell face into apical medium without evidence for infection. However, when exposed to IgA-EBV as unpolarized single-cell suspensions, MDCK cells expressed EBV immediate-early and early antigens. These results suggest that pIgR-mediated transcytosis of pIgA-EBV through epithelium facilitates endogenous spread of EBV in long-term virus carriers, with infection being confined to cells with altered polarity from prior cytopathology.

Animals↗
PubMed1996

Detection of Epstein-Barr virus genome in ocular tissues.

BACKGROUND: Epstein-Barr virus (EBV) is a ubiquitous mucosal pathogen with a propensity for lifelong, asymptomatic persistence. Because of reported association between EBV and ocular inflammatory disorders, we tested ocular tissues from normal eyes for presence of the EBV genome. METHODS: Ten freshly harvested cadaveric human eyes were dissected into limbal cornea, central cornea, aqueous humor, iris, vitreous humor, and optic nerve. Total cellular DNA preparations were screened for DNA sequences specific to EBV's large internal repeat region. After Southern transfer, polymerase chain reaction products were detected by a 32P-labeled oligonucleotide probe specific to amplified sequences internal to the polymerase chain reaction primers. RESULTS: Seven of ten eyes from deceased donors yielded a polymerase chain reaction product, indicating presence of EBV genome. In all, 12 (20%) of 60 cadaveric ocular samples contained EBV DNA. Only the optic nerve was consistently negative for EBV DNA. CONCLUSIONS: Detection of EBV DNA in cadaveric ocular tissues indicates a broad anatomic distribution of this persistent mucosal pathogen. The frequency with which EBV was found at apparently normal ocular sites raises the possibility for viral involvement in disease states, but emphasizes the need for specific criteria to implicate EBV in ocular pathology.

Cadaver↗
PubMed1996

Do admitted patients held in the emergency department impact the throughput of treat-and-release patients?

OBJECTIVE: To examine the impact of reducing ED "boarders" (through the use of a short-stay inpatient medicine unit) on the amount of time that treat-and-release patients spend in the ED. METHODS: A retrospective analysis of hours spent in the ED was made at a university hospital teaching ED for treat-and-release patients in 4 clinical categories: chest pain, asthma exacerbation, sickle-cell crisis, and seizure. The average hours per patient spent in the ED during the 4-month intervals before (August-November 1993) and after (August-November 1994) the establishment of the short-stay medicine unit were compared. Data were analyzed using the 2-tailed, unpaired t-test. RESULTS: This short-stay inpatient medicine unit received on average 135 patients per month from the ED, with an average length of stay of 2.4 days. The mean (+/-SD) number of admitted patients per day waiting in the ED > 8 hours for an inpatient bed dropped from 9.6 +/- 4.2., before the institution of this unit, to 2.3 +/- 2.6. There was a significant reduction in the average number of hours spent in the ED by treat-and-release patients with chest pain (from 7.3 +/- 6.0 to 5.5 +/- 4.8 hr/patient, p < 0.001) and asthma exacerbation (from 5.0 +/- 3.6 to 4.2 +/- 2.9 hr/patient, p < 0.05), but not with sickle-cell crisis or seizure, after the implementation of the short-stay unit. CONCLUSION: Reducing the number of admitted patients waiting in the ED for inpatients beds, in this case by establishment of a short-stay medicine unit, is associated with a decrease in the interval that treat-and-release patients spend in the ED.

Adult↗
PubMed1995

Adenovirus epithelial keratitis.

The authors sought to determine whether adenovirus could infect human corneal epithelium in vivo. They reviewed the medical records of six patients with adenovirus-positive viral corneal cultures who were examined at the Bascom Palmer Eye Institute between March 21, 1986, and December 31, 1992. The six patients with adenovirus-positive viral corneal cultures included one patient with dendritic epithelial keratitis, one with geographic epithelial ulceration, three with both geographic ulceration and contiguous dendrites, and one with heaped-up corneal epithelium but no ulceration. Four patients had rose bengal solution applied to their ocular surface, and in all four patients rose bengal uptake was seen at the epithelial edges of the dendrite or geographic ulceration in a manner characteristic of herpes simplex viral keratitis. Serotype determination of the isolates showed adenovirus type 3 (one patient), type 8 (three patients), type 19 (one patient), and indeterminate (one patient). Results of monoclonal antibody staining of cultures against herpes simplex virus (types 1 and 2) antigens was negative for all six cases. Adenovirus epithelial keratitis may result from infection of human corneal epithelium by the virus and rarely may mimic infection of corneal epithelium by herpes simplex virus.

Adenovirus Infections, Human↗
PubMed1994

A thymidine kinase deficient HSV-2 strain causes acute keratitis and establishes trigeminal ganglionic latency, but poorly reactivates in vivo.

The incidence of herpetic keratitis following intranasal or direct ocular infection with thymidine kinase-negative (TK-) strains of herpes simplex virus (HSV)-2 has not been well studied, and the role of the TK gene in the establishment of latency and virus reactivation is controversial. To determine whether a TK- strain of HSV-2 could establish trigeminal ganglionic latency and be reactivated in vivo to produce recurrent keratitis or nervous system infection, an animal model of acute and recurrent infection was utilized. Rabbits were infected by the intranasal or ocular routes, and latency was reactivated by immunosuppression. Virus shedding in nasal and ocular secretions was monitored, and the eyes were examined for the presence of corneal epithelial lesions during acute and reactivated infections. Central nervous system (CNS) and trigeminal ganglionic tissues were assayed by histologic, virologic, and in situ hybridization techniques. All rabbits intranasally infected shed virus in both ocular and nasal secretions, whereas only 30% of rabbits infected in the eyes shed virus in nasal secretions. Virus was recovered from cocultivation cultures, but not from cell-free homogenates, of trigeminal ganglionic and CNS tissues from animals inoculated by both routes. The incidence of keratitis was much greater after direct ocular inoculation, although both routes of inoculation produced CNS and ganglionic inflammatory lesions. Keratitis healed in 92% of the animals infected by the ocular route by 26 days post infection. Of rabbits initially infected in the eyes and then subjected to drug-induced reactivation, only 30% shed virus, which was limited to a 24 hour period; there was no reappearance of epithelial keratitis, no animal became blind, and none died. In contrast, latently infected control rabbits uniformly reactivated. These studies show that this TK-HSV-2 strain (i) replicates in the eye, (ii) is neuroinvasive but non-neurovirulent following intranasal and direct ocular infection; (iii) sheds in the eye more frequently and for longer periods after ocular than after intranasal inoculation; (iv) induces epithelial keratitis that usually heals spontaneously; (v) establishes latency in trigeminal ganglionic neurons, but no other ganglionic cells; and, (vi) reactivates in a small proportion of animals, but does not produce recurrent ocular lesions following drug-induced immunosuppression. Thus, the TK gene appears directly involved in HSV latency and reactivation in vivo.

Animals↗
PubMed1994

Staining characteristics and antiviral activity of sulforhodamine B and lissamine green B.

PURPOSE: Fluorescein and rose bengal are dyes used routinely in the examination of the ocular surface. As part of an ongoing search for a superior ophthalmic dye with optimal specificity and sensitivity and a lack of interference with subsequent viral cultures, and as part of studies that use chemical dyes to understand better the pathophysiology of ocular surface disorders, the staining characteristics and antiviral activity of sulforhodamine B and lissamine green B were investigated. METHODS: Staining of rabbit corneal epithelial cell cultures by sulforhodamine B and lissamine green B was compared to that of fluorescein and rose bengal. Diffusion of each dye through a collagen gel was measured. Uptake of lissamine green B by herpes simplex virus type 1 (HSV-1)-infected Vero cell cultures was compared at several times postinfection. The effect of sulforhodamine B and lissamine green B on HSV-1 plaque formation in Vero cells was determined. The cellular toxicity of sulforhodamine B and lissamine green B in vitro was examined by a quantitative 14C-amino acid uptake assay and by a qualitative cell viability assay. Finally, the effect of sulforhodamine B and lissamine green B on viral replication was compared in vivo with that of rose bengal in a rabbit model of herpetic epithelial keratitis. RESULTS: Rose bengal vividly stained cell monolayers of explant cultures of rabbit corneal epithelium. By light microscopy, sulforhodamine B and lissamine green B, like fluorescein, did not stain the epithelial cells, but did stain the corneal explant stroma. Pretreatment of epithelial cells with 0.25% trypsin for 5 minutes failed to induce dye uptake; however, pretreatment with 0.5% Triton X-100 for 5 minutes resulted in nuclear staining by lissamine green B, but not sulforhodamine B. When added to a collagen gel, the relative diffusion rate was fluorescein > lissamine green B > sulforhodamine B > rose bengal. By spectrophotometric analysis, HSV-1-infected and uninfected Vero cells bound equivalent amounts of lissamine green B until late in infection, when infected cells took up more dye (P < 0.001). A direct neutralization assay showed that 0.06% lissamine green B or 0.5% sulforhodamine B reduced HSV-1 plaque formation in Vero cells by greater than 50%, when present at the time of viral adsorption. By a quantitative 14C-amino acid uptake assay, lissamine green B was toxic to Vero cells in a dose-dependent manner, whereas sulforhodamine B was relatively nontoxic at the concentrations tested. By a cell viability assay, however, neither dye showed significant cellular toxicity. In a rabbit model of herpetic epithelial keratitis, rose bengal significantly reduced viral replication and recovery, whereas sulforhodamine B and lissamine green B had no effect. CONCLUSIONS: Neither sulforhodamine B nor lissamine green B stain healthy, normal cells. Lissamine green B stains membrane-damaged epithelial cells, but sulforhodamine B does not. Both sulforhodamine B and lissamine green B stain corneal stroma. Lissamine green B inhibits HSV-1 plaque formation at low concentrations of dye in vitro, which correlates with suppression of cellular metabolism as demonstrated by a 14C-amino acid uptake assay, but does not affect cell viability. Neither sulforhodamine B nor lissamine green B inhibit viral replication or recovery in vivo.

Animals↗
PubMed1992

Ophthalmomyiasis: a review with special reference to Cochliomyia hominivorax.

Ophthalmomyiasis, infestation of the eye by dipterous fly larvae, may result in sequelae ranging from minor irritation to blindness, disfigurement, and death. Infestation with Cochliomyia hominivorax, a medically significant and economically important species, exemplifies the mechanisms by which larvae can cause tissue damage. Although clinical history may be suggestive of ophthalmomyiasis, the definitive diagnosis requires direct observation of larvae. Treatment of ophthalmomyiasis involves removal or destruction of the larvae, if alive, and appropriate management of any sequelae. Preventive measures may not always be successful.

Animals↗
PubMed1992

Rose bengal inhibits herpes simplex virus replication in vero and human corneal epithelial cells in vitro.

Rose bengal dye is thought to highlight corneal lesions induced by herpes simplex virus type 1 (HSV-1) by virtue of its binding to dead or dying HSV-1-infected epithelial cells. However, whether rose bengal binds specifically to damaged versus normal corneal epithelial cells is unclear. To determine the binding properties of rose bengal, the authors compared binding of the dye to HSV-1-infected and uninfected cells, determined the cellular binding sites of the dye, and investigated the effects of rose bengal on HSV-1 replication in dye-treated cells in vitro. Spectrophotometric analysis revealed that uninfected and infected Vero cells bound equivalent amounts of dye at several times post inoculation, indicating that rose bengal does not preferentially bind to HSV-1-infected cells. By light microscopy, rose bengal was found to bind to the cell nuclei and perinuclear region of human corneal epithelial cells (HCEC) and Vero cells. Pretreatment of Vero and HCEC with different concentrations of rose bengal and exposure to 148 microW/cm2 of white light for 2 min reduced the ability of both cell types to support HSV-1 replication. Vero cells, in the absence of rose bengal, supported HSV-1 replication, whereas pre-treatment with 0.05% rose bengal reduced the yield of HSV-1 by 99.99% (P less than 0.000001) and 1% rose bengal completely prevented HSV replication. HCEC supported HSV-1 replication in the absence of rose bengal, but pre-treatment with 1% or 0.05% rose bengal completely prevented HSV-1 replication (P less than 0.000001).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗