Search PubMed⌕ Search

Biomedical subjects

J L Baum

Publications and source records attributed to J L Baum.

At least 37 records · Page 2Linked to original sources
PubMed1979

Intraocular levels of cefamandole compared with cefazolin after subconjunctival injection in rabbits.

We compared the intraocular pharmacokinetics of cefazolin with those of cefamandole, a recently marketed cephalosporin with enhanced activity against gram-negative bacilli. Following subconjunctival injection of 12.5 mg into infected eyes (S. aureus endophthalmitis) of pigmented rabbits, both drugs reached peak concentrations greater than 100 microgram/gm in cornea, sclera, and choroid-retina. The half-life was markedly shorter in sclera and choroid-retina than in cornea. Levels in the aqueous humor rose and fell more slowly than those in ocular tissues, reaching a maximum of only 5 to 10 microgram/ml. The pharmacokinetics of the two drugs were virtually identical in most intraocular sites. When cefazolin, which was less irritating than cefamandole by the subconjunctival route, was given in a dosage of 100 mg, levels in ocular tissues were increased by twofold to fourfold and in aqueous humor by 15-fold, compared to the concentrations produced by the 12.5 mg dosage. Levels in the vitreous humor were exceedingly low with both drugs; mean peak concentrations were 0.24 microgram/ml after the 12.5 mg dosage of cefamandole and less than 1.6 microgram/ml after the 100 mg dose of cefazolin.

Animals↗
PubMed1978

Cryosurgical iridocyclectomy.

A new surgical technique, cryosurgical iridocyclectomy, was used in the excision of an iris melanoma encroaching on the ciliary body. Iris-tumor-anterior ciliary body segment was removed en bloc. The elucidate the mechanical basis for the success of the procedure, similar operations were performed on three enucleated eyes. It was confirmed that traction on the iris by a cryoprobe resulted in forward movement of the ciliary body without iridodialysis. The iceball that formed prevented iridodialysis at its usual plane of cleavage. Cryosurgical iridocyclectomy is recommended for excision of small discrete iris tumors that encroach on the anterior ciliary body.

Adult↗
PubMed1978

Peripheral corneal infiltrates following intravenous injection of diatrizoate meglumine.

A 66-year-old white man developed bilateral peripheral corneal infiltrates on two separate occasions after intravenous injections of a radiopaque dye containing iodide. To our knowledge this is the first case of drug-induced ocular hypersensitivity reaction associated with the administration of these dyes and manifesting with peripheral corneal infiltrates.

Aged↗
PubMed1978

The treatment of bacterial endophthalmitis.

Restoration of good visual acuity following bacterial endophthalmitis is dependent on prompt diagnosis, immediate treatment, proper selection of antibiotics, high-dose parenteral and periocular antibiotic therapy, and systemic and periocular corticosteroids. Antibiotic selection should be based on the statistical incidence of pathogens rather than on the result of a Gram stain from the aqueous or vitreous humor. Recent experimental studies in the primate eye suggest that there is little to choose between the subconjunctival and retrobulbar routes of antibiotic administration. The role of intravitreal injection of antibiotic, although promising, requires further definition.

Animals↗
PubMed1978

Synthesis of glycosaminoglycans by cultures of normal human corneal endothelial and stromal cells.

Monolayer cultures of normal human corneal endothelial and stromal cells were incubated with [35S]sulfate and [3H]glucosamine for 4 hr. The labeled glycosaminoglycans resulted from this incubation were isolated from the cell layer and the growth medium and further characterized. Both endothelial and stromal cell cultures synthesized a variety of sulfated glycosaminoglycans, with chondroitin 6-sulfate as the major product. Chondroitin 4-sulfate, dermatan sulfate, and heparan sulfate were present in smaller amounts. Keratan sulfate was produced only in minimal amounts. Both cell types also synthesized hyaluronic acid. The hyaluronic acid production in stromal cell strains derived from donors of different ages was similar. The demonstration that the endothelial cell strain derived from a 1-day-old baby contained more hyaluronic acid than cultures from older donors suggests a possible age-related phenomenon as seen in developing tissues.

Adolescent↗
PubMed1977

Late spontaneous clearing of corneal grafts.

Three cases of graft rejection or primary donor failure after penetrating keratoplasty failed to respond to treatment. After cessation of therapy, these edematous corneas all cleared spontaneously in six to 17 months with the return of excellent vision. It is suggested that repeated keratoplasty be delayed up to 18 months in certain instances.

Administration, Topical↗
PubMed1977

Comparing radioactive and trephine-disk bioassays of dicloxacillin and gentamicin in ocular tissues in vitro.

Trephined disks of tissue (6 mm diameter) from fresh rabbit eyes were immersed overnight in solutions of radioactive carbon (14C)-dicloxacillin or gentamicin, then assayed by one of two methods: agar-diffusion bioassay, using filter-paper disks immersed in known concentrations of antibiotic as standards, or radioactive assay. The bioassay underestimated the concentrations of antibiotic in sclera and iris by 38 to 72%, and slightly overestimated those in the cornea. A corrected bioassay was calculated, based on the differences in fluid mass between tissue specimens and filter-paper disks; this value was within 20% of the radioactive assay in 18 of 24 experiments with dicloxacillin, and in 14 of 24 with gentamicin. There was evidence of pronounced binding of gentamicin to ocular tissues (iris greater than sclera greater than cornea); this appeared to be a saturable and reversible phenomenon. Less marked binding of dicloxacillin to iris and sclera was noted. The results indicated that, depending on the degree of accuracy required, the corrected trephine-disk agar-diffusion bioassay provides a reasonable estimate of the antibiotic content of ocular tissues.

Animals↗
PubMed1977

Regional differences in ocular concentration of gentamicin after subconjunctival and retrobulbar injection in the rabbit.

We compared the penetration of radioactive carbon (14C) labeled-gentamicin into ocular tissues and fluids of albino rabbit eyes after subconjunctival (anterior subtenon's) and retrobulbar (posterior subtenon's) injections. In both normal and infected (Staphylococcus aureus endophthalmitis) eyes, higher levels of drug were produced with subconjunctival rather than with retrobullar admininistration in cornea, sclera, choroid and retina (as a unit), and iris; levels in the aqueous and vitreous humors of infected eyes were similar with the two routes of injection. Marked regional variations in the concentrations of gentamicin were noted in cornea, sclera, and choroid-retina after subconjunctival therapy. The pattern of these variations suggests that subconjunctival antibiotic penetrates the eye by direct diffusion. The low levels of drug after retrobulblar injection may be due to systemic absorption through the highly vascular orbital plexus of the rabbit.

Absorption↗
PubMed1976

The synthesis of glycosaminoglycans by cultures of rabbit corneal endothelial and stromal cells.

Confluent monolayer cultures of rabbit corneal endothelial and stromal cells were incubated independently with [35S]sulphate and [3H]glucosamine for 3 days. AFter incubation, labelled glycosaminoglycans were isolated from the growth medium and from a cellular fraction. These glycosaminoglycans were further characterized by DEAE-cellulose column chromatography and by sequential treatment with various glycosamino-glycan-degrading enzymes. Both endothelial and stromal cultures synthesized hyaluronic acid as the principal product. The cell fraction from the stromal cultures, however, had significantly less hyaluronic acid than that from the endothelial cultures. In addition, both types of cells synthesized a variety of sulphated glycosaminoglycans. The relative amounts of each sulphated glycosaminoglycan in the two cell lines were similar, with chondroitin 4-sulphate, chondroitin 6-sulphate and dermatan sulphate as the major components. Heparan sulphate was present in smaller amounts. Keratan sulphate was also identified, but only in very small amounts (1-3%). The presence of dermatan sulphate and the high content of hyaluronic acid are similar to the pattern of glycosaminoglycans seen in regenerating or developing tissues, including cornea.

Animals↗
PubMed1976

Flavobacterium endophthalmitis following keratoplasty. Use of a tissue culture medium-stored cornea.

This case of Falvobacterium meningosepticum endophthalmitis in the immediate postoperative period following a penetrating keratoplasty represents the first known isolation of F meningosepticum from the eye and, also, our first encounter with bacterial endophthalmitis following keratoplasty. This case occurred soon after conversion from whole eye moist chamber storage to tissue culture storage (McCarey-Kaufman medium). This storage technique may predispose to development of postoperative endophthalmitis. We offer suggestions to minimize the possibility of such infection.

Aged↗
PubMed1976

The stability of ten antibiotics in artificial tear solutions.

We determined the relative potencies of penicillin G, carbenicillin, oxacillin, cephalothin, cephaloridine, gentamicin, kanamycin, neomycin, vancomycin, and bacitracin after their addition to three commercially available 0.5% hydroxypropyl methylcellulose artificial tear solutions in plastic squeeze bottles. We found no significant loss of antibiotic activity at room temperature over a period of seven days for all antibiotics except penicillin G, cephalothin, and cephaloridine. Three of the antibiotics were insoluble in one or more of the artificial tear solutions.

Anti-Bacterial Agents↗
PubMed1976

Keratomalacia in the cachectic hospitalized patient.

Keratomalacia occurred in two cachectic hospitalized patients, each with severe vitamin A-protein deficiency secondary to a lethal disease. Prompt therapy with parenteral and topical vitamin A, protein supplementation, and a soft contact lens restored corneal integrity and prevented visual loss in one patient. Keratinization of the conjunctiva did not occur in either patient. Patients with severe protein deficiency may develop keratomalacia in the absence of a severely decreased serum level of vitamin A.

Adult↗
PubMed1975

The effect of corticosteroids in the treatment of experimental bacterial endophthalmitis.

We evaluated the effects of the addition of corticosteroids to antibiotic therapy in the treatment of staphylococcal endophthalmitis in rabbits. Twenty-four hours after the induction of infection with Staphylococcus aureus, penicillin G, penicillin G and dexamethasone or prednisolone, or saline was injected retrobulbarly for ten days. Afterward, there was no ophthalmoscopic difference between the penicillin and corticosteroid-treated group and those animals receiving only penicillin G. At day 60, however, the fundus was visible in 64% of eyes treated with penicillin G with corticosteroids in contrast to 39% of those eyes treated only with penicillin G (P less than .025). The results between dexamethasone and prednisolone use were not significant. Retrobulbar corticosteroids in combination with effective antibiotic therapy effectively treated experimental bacterial endophthalmitis.

Animals↗