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Biomedical subjects

R E Christensen

Publications and source records attributed to R E Christensen.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1981

Suppression of adrenergic adaptation in the eye with a prostaglandin synthesis inhibitor.

The treatment of glaucoma patients with a topical medication is sometimes associated with adaptation (the development of subsensitivity) to the effect of the medication. In the rabbit eye, adaptation develops when norepinephrine is administered topically on a daily basis. A marked decrease in the intraocular pressure is observed the first day, but diminishing responses are observed on subsequent days. Since prostaglandins may be released in response to catecholamines and have been found to inhibit adrenergic neurotransmission, we treated rabbits with topical flurbiprofen, a potent cyclooxygenase (prostaglandin synthesis) inhibitor, to suppress adaptation to norepinephrine. The results demonstrate a significant suppression of adaptation in the concentration range of 0.001% flurbiprofen (p less then 0.0005). This finding supports the theory that cyclooxygenase products mediate the development of adaptation to exogenous norepinephrine in the rabbit eye.

Adaptation, Ocular↗
PubMed1980

Orbital abscess.

A staphylococcal orbital abscess developed in a 55-year-old diabetic woman. Initial antibiotic therapy was apparently incomplete and resulted in an unusual clinical manifestation for an orbital infection. These unusual features included an insidious course of monocular visual loss and proptosis in the absence of fever, substantial orbital pain, and evidence of sinus disease; pancytopenia rather than leukocytosis was present. Surgical drainage followed by intravenous and oral antibiotic therapy resulted in marked clinical improvement, including a partial return of visual acuity. In the patient, however, a staphylococcal osteomyelitis of the shoulder and subsequent fatal septicemia developed several months later. Orbital infection continues to be a life-threatening condition, especially in debilitated patients.

Abscess↗
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↗