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Biomedical subjects

J W Chandler

Publications and source records attributed to J W Chandler.

At least 19 recordsLinked to original sources
PubMed1992

Conjunctivitis of the newborn.

Infectious conjunctivitis of the newborn is caused by a wide variety of microorganisms. The ocular findings may be part of a widespread systemic infection. Clinical presentations are not diagnostic of the cause, and a microbiologic work-up with cytology, cultures, and microbial sensitivities is mandatory. The selection of specific antimicrobial therapy is based on the findings of laboratory studies. Prophylaxis with silver nitrate solution, 1.0% tetracycline, or 0.05% erythromycin ointment is effective for the prevention of gonococcal and chlamydial conjunctivitis in the newborn.

Anti-Bacterial Agents↗
PubMed1991

Indications for penetrating keratoplasty: 1980-1988.

A retrospective analysis was undertaken of the clinical diagnoses of 1594 eyes that underwent penetrating keratoplasty performed in a private-referral corneal practice over a 9-year period, 1980-1988. The seven most common indications for surgery were keratoconus (24.0%), pseudophakic or aphakic bullous keratopathy (21.2%), corneal scarring (13.9%), Fuchs' endothelial dystrophy (12.5%), regraft (8.1%), and herpetic keratitis (5.3%). Keratoconus was the leading indication from 1980 to 1985. From 1985 to 1988, pseudophakic bullous keratopathy became the leading indication and correlates well with known complications associated with closed-loop anterior chamber lenses, which were widely used during the early 1980s. Less frequent indications for penetrating keratoplasty included the following: infectious (nonviral) keratitis (3.5%); acute or chronic ulcerative keratitis (2.7%); interstitial keratitis (1.8%); mechanical trauma (1.5%); other (non-Fuchs') corneal dystrophies (1.4%); congenital opacities (0.8%); and chemical burns (0.5%).

Aphakia↗
PubMed1990

Heparin and infarct coronary artery patency after streptokinase in acute myocardial infarction.

Anticoagulant therapy is frequently used after thrombolytic agents in the treatment of acute myocardial infarction (AMI) although it is unclear that such therapy will prevent subsequent infarct vessel reocclusion. The role of duration of heparin therapy in maintaining infarct artery patency was studied retrospectively in 53 consecutive AMI patients who received streptokinase therapy and underwent coronary angiography acutely and at 14 +/- 1 days. Of the 39 patients with initial infarct vessel patency, patency at follow-up angiography was observed in 100% (22 of 22) of those who received greater than or equal to 4 days of intravenous heparin but in only 59% (10 of 17) of those patients who received less than 4 days of heparin (p less than 0.05). Of the 14 patients not initially recanalized after streptokinase, patent infarct-related arteries at follow-up angiography were found in 3 of 8 (38%) treated with greater than or equal to 4 days of heparin therapy but in none of the 6 patients treated for less than 4 days (difference not significant). No significant difference in hemorrhagic complications was noted between the short- and long-term heparin treatment groups. Thus, greater than or equal to 4 days of intravenous heparin therapy after successful streptokinase therapy in AMI is more effective in maintaining short-term infarct vessel patency than a shorter duration of therapy and it may maintain the short-term patency of the infarct vessel in those patients who later spontaneously recanalize.

Angiography↗
PubMed1990

Lack of T6 induction on human corneal Langerhans cells in vitro.

Previous studies have shown that Langerhans cells (LC) in normal human corneas differ from their counterparts in other epithelia (eg, skin, gingival, cervical) by their lack of the thymocyte antigen T6 on their membranes. In those studies only three out of four very young infant corneas (newborn, 3-day-, 8-day-old) have displayed positive T6 staining to date. Corneas from older infants and adults have demonstrated no such staining. This study tested the capacity of corneal LC to express T6 by in vitro induction with several immunomodulating agents. Human gamma interferon (IFN gamma was tested at 1000 U/ml, 500 U/ml and 100 U/ml. Interleukin-1 (IL-1) was tested at 100 U/ml, 50 U/ml and 20 U/ml. Thymopoietin pentapeptide (TP-5) was tested at 10 micrograms/ml, 1 micrograms/ml and 0.1 microgram/ml. Combinations of these agents were also tested in a similar fashion. None of these immunomodulating agents or combinations of them were able to induce T6 expression on normal corneal LC. This may reflect an innate incapacity of these cells to express this antigen or dosage requirements in excess of those tested.

Antibodies, Monoclonal↗
PubMed1990

In vivo induction of Ia expression in murine cornea after intravitreal injection of interferon-gamma.

Intravitreal injection of interferon gamma (IFN-gamma) induces increased expression of Class II major histocompatibility complex (Ia) antigen expression on corneal endothelial cells and stromal fibroblasts. In contrast, IFN-gamma has no detectable effect on Ia antigen expression in epithelium. Induction of Ia antigen expression was rapid with increases detectable as early as 6-12 hours after a single injection of 1 x 10(5) units. Expression peaked at 24-48 hours and decreased to background levels by 120 hours. The Ia antigen expression increased in a dose-dependent manner, and IFN-gamma treatment also induced the synthesis of increased amounts of a 65-kilodalton (kD) protein in the cornea. Increased levels of this 65-kd protein are seen as early as 12 hours after treatment and can be induced with as little as 1 x 10(2) units of IFN-gamma. The function of the 65-kd protein is unknown. This model should be useful in studies on in vivo modulation of Ia antigen expression.

Animals↗
PubMed1989

Severe aortic regurgitation complicating percutaneous aortic valve valvuloplasty.

An 88-year-old patient undergoing percutaneous aortic balloon valvuloplasty of a tricuspid aortic valve is described. The patient had mild aortic regurgitation prior to the procedure but developed severe aortic regurgitation after balloon dilatation of the valve. At the time of surgery there was no anatomic disruption of the valve or supporting structures. Development of severe aortic incompetence following balloon valvuloplasty has not been previously reported.

Aged↗
PubMed1989

Proteoglycans of rabbit corneas with nonperforating wounds.

Rabbit corneal proteoglycans were labeled by intrastromal injection of 3H-glucosamine and 35S-sulfate 1 and 2 weeks after partial-thickness radial scalpel incisions. Proteoglycans were extracted with guanidine-HCl and purified by ion exchange chromatography. Wounding caused a marked decrease in the total incorporation of labeled precursors into proteoglycans. The labeled proteoglycans were more readily extracted with guanidine-HCl after wounding. Labeled proteoglycans from wounded corneas had a larger molecular size on gel filtration chromatography than did proteoglycans from control corneas, a result of an increased amount of keratan sulfate in the large molecular size fractions. Analysis of labeled glycosaminoglycan (GAG) from guanidine-extracted proteoglycans and from the corneal tissue after guanidine-HCl extraction showed an increase in the relative amount of heparan sulfate and keratan sulfate after wounding, and a decrease in relative amount of dermatan sulfate. The 35S:3H ratio of heparan and dermatan sulfates increased after wounding, and that of keratan sulfate decreased, suggesting changes in sulfation. Degradation of labeled dermatan sulfate with hyaluronidase and with periodate revealed a 2-fold increase in iduronic acid content and 2-4-fold increase in hyaluronidase-resistant dermatan sulfate in the wounded corneas. Reduction in proteoglycan content, reduced sulfation of keratan sulfate, and accumulation of a high-sulfate, high-iduronic acid dermatan sulfate are previously reported properties of proteoglycan in scar tissue from perforating corneal wounds. Demonstration of these properties in proteoglycan after wounds similar to radial keratotomy incisions suggests that deposition of scar tissue can result from wounds which do not damage Descemet's membrane.

Animals↗
PubMed1987

HLA-DR+/T6- Langerhans cells of the human cornea.

We have investigated normal human corneas for the presence of T6-marker on Langerhans cells. With the exception of one pair of newborn corneas and two pairs of very young infant corneas, all HLA-DR-positive cells in central and peripheral corneal epithelium were T6-negative by double-labeled immunofluorescence. In contrast, epidermal sheets from normal human eyelid skin displayed positive staining for T6 on most of the HLA-DR-positive Langerhans cells. Since T6 antigen is considered to be a specific Langerhans cell differentiation marker, we interpret this finding to indicate a nonactivated or undifferentiated state of Langerhans cells in normal human corneas.

Adolescent↗
PubMed1987

Prophylactic effects of silver nitrate and erythromycin on Chlamydia psittaci conjunctivitis.

An animal model has been developed to study the effects of various prophylaxis agents on acquisition of chlamydial conjunctivitis. When Hartley strain newborn guinea pigs received ocular inoculations of Chlamydia psittaci followed by the instillation of various agents, 1% AgNO3 significantly lowered the risk of developing chlamydial conjunctivitis if it was administered within 15 min after the inoculation with C. psittaci. However, if the AgNO3 was administered at either 1 hr or 2 hr following inoculation, it did not have any prophylactic effect on the development of chlamydial conjunctivitis. Erythromycin ointment, 0.5%, was also found to prevent chlamydial conjunctivitis. The prophylactic effect was similar to placebo when the drug was given at 15 min; however, erythromycin ointment prophylaxis 1 hr or 2 hr after inoculation with C. psittaci was statistically superior to placebo.

Animals↗
PubMed1986

Diagnosis of anterior chamber metastasis by serologic marker found during anterior chamber paracentesis.

A 29-year-old man developed anterior uveitis unresponsive to intensive topical and systemic therapy. He had recently completed a course of chemotherapy with apparent response and resolution of metastasis from a mixed germ cell tumor (embryonal carcinoma and seminoma). Anterior chamber paracentesis was nondiagnostic on two occasions for metastatic cells. At the time of his second paracentesis a tumor marker, human chorionic gonadotropin-beta subunit, was used to confirm the diagnosis of anterior chamber metastasis to the eye.

Adult↗