PubMed Health⌕ Search

Biomedical subjects

R E Christensen

Publications and source records attributed to R E Christensen.

At least 19 recordsLinked to original sources
PubMed1992

The distribution of the antimicrobial protein, calprotectin, in normal oral keratinocytes.

Calprotectin is a heterodimeric peptide isolated from neutrophil cytosol that exhibits profound antimicrobial effects. Using monoclonal antibody MAC 387, calprotectin was found to be expressed in oral keratinocytes from normal, non-inflamed oral mucosa. Orthokeratinized sites including the attached gingiva and hard palate expressed low levels of calprotectin with a restricted pattern; immunoreactants were identified only within subcorneal keratinocytes. Parakeratinized mucosa from the lips, soft palate, tongue and buccal mucosa expressed calprotectin in a more widespread, yet variable pattern, immunoreactants being detectable in only a portion of the spinous layer in some cases whereas in others the pattern of expression was more topographically diffuse. Antigen was not detected in basilar and lower strata cells. Both cytoplasmic and nuclear decoration could be identified. The results indicate that oral mucosa harbours an antimicrobial deterrent to micro-organisms that may enhance the physical epithelial barrier of host defence.

Antigens, Surface↗
PubMed1992

Results of inpatient and outpatient cataract surgery. A historical cohort comparison.

PURPOSE: The transition from inpatient to outpatient cataract surgery during the last decade was not accompanied by prospective investigation of its effect on visual outcomes or surgical complications. The authors performed this study to assess the impact of this transition on surgical results. METHODS: The authors reviewed 600 extracapsular cataract extractions performed by 4 experienced ophthalmic surgeons during a 36-month period; in 300 cases, patients were hospitalized after surgery (inpatient group), and, in 300 cases, patients were never hospitalized (outpatient group). The same surgical techniques were used in all cases. Visual outcome and rates for operative and postoperative complications were compared. RESULTS: There were no statistically significant differences between the inpatient and outpatient groups for visual acuity. Excluding patients with pre-existing nonlenticular ocular disease, a best-corrected visual acuity of 20/40 or better was achieved in 93.1% of inpatient cases and in 97.2% of outpatient cases 6 months after surgery. Postoperative, clinically apparent cystoid macular edema was more common in the inpatient group (P = 0.03); however, after exclusion of patients with diabetes, hypertension, age younger than 65 years, and eyes with pre-existing nonlenticular disease, there was no statistically significant difference between groups. No significant differences in rates for other operative and postoperative complications were identified, including wound dehiscence, unplanned postoperative filtering blebs, infectious endophthalmitis, retinal detachment, persistent iridocyclitis, glaucoma, and corneal edema. CONCLUSION: This study does not demonstrate that the transition to outpatient cataract extractions has had an adverse effect on surgical outcomes.

Aged↗
PubMed1991

The effects of Nd:YAG laser iridotomy on the corneal endothelium.

We studied 18 eyes of 18 patients undergoing Nd:YAG laser peripheral iridotomy for occludable anterior chamber angles. A Q-switched laser was used for all treatments. Preoperative and postoperative pachymetry and corneal endothelial cell counts were obtained centrally, in the nontreated superonasal quadrant, and in the treated superotemporal quadrant. No significant differences were found between preoperative and postoperative corneal thickness at any site. A small decrease in endothelial cell count (95 cells/mm2) at the treated site was statistically significant (P = .04).

Cell Count↗
PubMed1990

Biometric variables in patients with occludable anterior chamber angles.

Biometric studies of the ocular dimensions in eyes with narrow anterior chamber angles provide insight into the pathophysiology of pupillary block and may show which eyes are more prone to develop angle-closure glaucoma. We reviewed the records of 56 patients with occludable angles examined between 1980 and 1984. Initial biometric data obtained on the patients included corneal diameter, anterior chamber depth, lens thickness, and ocular axial length. The average length of follow-up was five years. Of 54 patients with complete clinical records, 20 (37%) eventually required peripheral iridectomy after a mean duration of 16 months from the initial examination. Cox's survival analysis showed a strong correlation between shortened duration to peripheral iridectomy and increasing lens thickness/ocular axial length ratio factor (P = .03). No other variables were significantly related to outcome. This suggests that the lens thickness/ocular axial length ratio may be useful as a predictor of clinical outcome in narrow-angle glaucoma.

Anterior Chamber↗
PubMed1990

Glaucoma in patients with uveitis.

The records of 100 patients (161 eyes) with uveitis were reviewed retrospectively to determine the prevalence of increased intraocular pressure, the forms of uveitis most commonly associated with glaucoma, and the forms that require specific glaucoma therapy. Secondary glaucoma was present in 23 patients (31 eyes): three of 24 patients with acute uveitis (three eyes, 12% of acute uveitis patients) and 20 of 76 patients with chronic uveitis (28 eyes, 26% of chronic uveitis patients). Eighteen patients (26 eyes, 78% of glaucoma patients) with chronic uveitis required long-term medical therapy to control intraocular pressure. Three patients (three eyes, 12% of glaucoma patients) with acute uveitis required short-term therapy to control intraocular pressure. The remaining two patients had transient increases in intraocular pressure that did not require treatment or that responded to treatment of intraocular inflammation alone. One patient with chronic uveitis (two eyes, 4% of glaucoma patients) required filtering surgery. At least five patients (eight eyes, 22% of glaucoma patients) had glaucomatous visual field defects. The results of this survey are consistent with the concept that secondary glaucoma is a management problem in patients with anterior segment inflammation and chronic rather than acute uveitis. An algorithm for the management of increased intraocular pressure in patients with uveitis is proposed.

Acute Disease↗
PubMed1989

A clinical evaluation of the BioPen.

We conducted a clinical trial on the Oculab BioPen, a portable, handheld applanation instrument designed to measure ocular axial lengths. We compared the measurements obtained from the BioPen with those obtained from the Ultrascan Digital B System IV from CooperVision. Accuracy and reproducibility were assessed in vitro by performing ten measurements with each instrument on a precalibrated 25.8-mm plastic test block. The in vivo reproducibility of the BioPen was evaluated by performing five serial readings on each eye of 58 patients. Keratometry measurements were also recorded to determine whether the BioPen provided consistent readings regardless of corneal curvature. We found the BioPen to be as accurate and reproducible as the Ultrascan Digital B in vitro and in vivo. Corneal curvature had no effect on the in vivo reproducibility of the BioPen.

Clinical Trials as Topic↗
PubMed1989

Effect of DMBA on oral cancer development in hamsters with latent HSV-1 infections in trigeminal ganglia.

This study examined the effect of 7, 12-dimethyl-benz(a)anthracene (DMBA), polycyclic aromatic hydrocarbon carcinogen, on pathologic changes in buccal pouch mucosa of hamsters with latent herpes simplex virus type 1 (HSV-1) infections in their trigeminal ganglia. Of the pouches receiving DMBA treatment, the average number of tumors per pouch was significantly higher (p less than 0.01) in pouches of animals with HSV-1 infections as compared to those that received DMBA only. Of the pouches receiving DMBA, the average cumulative tumor diameter (the sum of the tumor diameters in each group divided by the number of pouches in that group) was notably greater in animals with latent HSV-1 than in animals that had not been infected; however, this difference was not significant. The DMBA-treated hamsters that had latent infections also displayed a higher severity and prevalence of histopathologic changes in their pouch mucosa. This study indicates that latent HSV-1 and DMBA show synergism in the development of tumors and precancerous histopathologic changes in hamster buccal pouch mucosa. An unexpected finding was that among the HSV-1 infected animals, 95% of the ganglia from animals treated with DMBA showed latent HSV-1 virus on explanation culture, whereas only 10% of the ganglia from infected animals that received mineral oil, rather than DMBA, contained latent virus.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1988

Effects of argon laser iridotomy on the corneal endothelium.

We studied 14 eyes of 14 patients undergoing argon laser peripheral iridotomy for occludable (narrow) anterior chamber angles. Preoperative and postoperative pachymetry and corneal endothelial cell counts by specular microscopy were obtained centrally and in both the treated and nontreated superior quadrants. No significant differences were found between preoperative and postoperative measurements of corneal thickness and endothelial cell counts in any area.

Argon↗
PubMed1987

Glomangiosarcoma with metastasis to the maxilla.

A thorough review of the literature disclosed very little information on glomangiosarcoma with no reported cases of verified metastases. We present a case which may be the first instance of oral metastatic glomangiosarcoma to be reported in the literature.

Adult↗
PubMed1986

The electroretinogram in advanced open-angle glaucoma.

Fourteen patients with advanced open-angle glaucoma were evaluated prospectively by electroretinography and the results were compared with normal controls who were matched for age and sex. All glaucoma patients had visual acuity of 20/50 or better, cup-to-disc ratios of 0.7 or greater in at least one eye, and visual field loss consistent with advanced glaucoma. Numerous electroretinographic parameters were significantly abnormal when compared with the control group.

Adult↗
PubMed1985

Inhibition of the epinephrine-induced reduction of intraocular pressure by systemic indomethacin in humans.

In a prospective, randomized, double-masked study, 2% epinephrine applied topically twice each day for two weeks to the eyes of patients with glaucoma or ocular hypertension caused an 8.1 +/- 1.4-mm Hg (mean +/- S.E.M.) reduction of intraocular pressure in placebo-treated patients, but only a 1.9 +/- 0.6-mm Hg decrease in patients treated with 25 mg of orally administered indomethacin four times each day (P less than .0005). Systemic treatment with indomethacin for one week did not significantly increase intraocular pressure by itself (baseline, 19.7 +/- 0.6 mm Hg, vs 20.1 +/- 1.4 mm Hg after indomethacin treatment). When indomethacin treatment was discontinued in those patients receiving topical epinephrine, there was a further significant (P less than .05) reduction in intraocular pressure compared with the placebo-treated group. Since the ocular hypotensive effect of topically applied epinephrine is inhibited by indomethacin, a cyclo-oxygenase inhibitor, these results suggest that this reduction of intraocular pressure is at least partially mediated by the endogenous production of prostaglandins, or other cyclo-oxygenase products, and that the intraocular pressure of glaucoma patients undergoing epinephrine therapy may increase when systemic cyclo-oxygenase inhibitors such as indomethacin or aspirin are taken.

Administration, Oral↗
PubMed1985

Acute angle-closure glaucoma associated with surgical anesthesia.

We reviewed the records of all inpatients of the UCLA Medical Center from 1955 to 1980 with the discharge diagnosis of "glaucoma." Nine cases of acute angle-closure glaucoma occurring after spinal or general anesthesia were identified among the 913 records reviewed. Of the nine cases, two were bilateral. Seven patients were female and two were male; the mean age was 63 years. Six of the nine surgical procedures were extraperitoneal and abdominal or pelvic. Parenteral atropine sulfate or scopolamine hydrobromide was administered to seven patients and ephedrine sulfate to four; drug-induced mydriasis may have contributed to this complication. Succinylcholine chloride, which causes contraction of the extraocular muscles, was administered to six patients. Additionally, psychological stress in the surgical patient may increase the risk of this disease by causing mydriasis. Our cases are compared with previous reports.

Acute Disease↗
PubMed1979

Mercury residues in tissues of dead and surviving birds fed methylmercury.

Concentrations of mercury in passerine birds fed diets containing 40 ppm methylmercury were similar in tissues of birds that died from mercury poisoning and in those that were sacrificed after half the group had died. Residues were higher in tissues of birds that died, but the differences were not statistically significant. Residue levels were highest in livers, followed by kidneys and brains. Levels of mercury were similar in breast muscle, carcass, and whole body. Mercury levels were highest in redwinged blackbirds, lowest in grackles, and intermediate in starlings and cowbirds. Mercury concentrations exceeded 20 ppm in all tissues of all species and were similar to levels reported in wild birds known to have died of mercury poisoning.

Animals↗
PubMed1978

Intraoral juvenile xanthogranuloma.

A case of juvenile xanthogranuloma of the gingiva is presented. This uncommon, benign disorder has rarely been histologically documented in the oral cavity, and rarely have oral lesions been described as presenting symptoms prior to this report. The pertinent literature is reviewed and possible etiologic factors are discussed.

Child, Preschool↗
PubMed1978

Extracondylar osteochondromas of the jaws.

A review of the literature and the addition of two new cases have revealed that according to a histologic criterion there are presently twenty reported cases of osteochondroma of the jaws located outside the condyles. Although most of the extracondylar lesions have occurred on the coronoid process, cases are now reported on the maxilla and the body of the mandible. The clinical features of these lesions are compared with those located in the condyle, and the radiographic and surgical approaches of the extracondylar lesions are discussed.

Age Factors↗