Evidence for a hierarchical mating system operating via pheromones in Dictyostelium giganteum.

Studies of four mating types of the cellular slime mold Dictyostelium giganteum revealed that each strain secrets its own sexual hormone to which each of the other three strains responds by forming macrocysts. Based on the ability to secrete or respond to hormone, the four strains can be arranged in a mating-type hierarchy.

Evidence for chemotaxis during sexual development in Dictyostelium discoideum.

Amoebae in mated cultures of Dictyostelium discoideum show oriented movement towards young aggregates, suggesting that cemotaxis is involved in macrocyst development. Amoebae also show directional movement towards midendocyte stages, indicating that as the macrocyst develops it continues to be a source of chemoattractant. These data are discussed in terms of our current knowledge about mating in the cellular slime moulds.

An animal model of Fusarium solani endophthalmitis.

Infection with Fusarium solani was established by injecting spores into the anterior chambers of outbred Wistar rats. The disease produced was remarkably similar to that reported in man and progressed to a fulminating endophthalmitis. Attenuation of the disease could be accomplished by repeated animal passage of the isolate.

Cell differentiation during fruiting body formation in polysphondylium pallidum.

The spatial pattern of cellular differentiation was studied during fruiting body formation in Polysphondylium pallidum using 3 different staining methods: Calcofluor fluorescence (cellulose accumulation), neutral red (prestalk cells) and immunofluorescence (prespore cells). Neutral-red staining revealed the existence of a clear prestalk region which becomes evident during aggregation and continues throughout culmination. Immunofluorescent staining demonstrated that cells in the prestalk region gradually lose their presporeness (fluorescence) as they are transformed into differentiated stalk cells.

Interaction of topical and oral timolol in glaucoma.

The interaction of oral and topical timolol maleate was studied in patients with open-angle glaucoma. The oral and topical preparations given separately produced a significant and comparable reduction of the intraocular pressure, but no additive effect was observed when both preparations were given together. Pulse- and blood pressure-lowering effects of oral timolol were not enhanced by the application of topical timolol.

Clinical implications of preseptal (periorbital) cellulitis in childhood.

The available hospital records of all pediatric patients diagnosed as having periorbital, preseptal or orbital cellulitis over a five-year period were reviewed and compared to previously reported series. Only two of 39 patients had orbital cellulitis. The 37 patients with preseptal cellulitis had two characteristic clinical presentations.

Colchicine induces multiple axis formation and stalk cell differentiation in Dictyostelium discoideum.

Colchicine is shown to have several effects on the development of the pseudoplasmodia of the cellular slime mould Dictyostelium discoideum. At concentrations of 0.01 M and above culmination was prevented, while differentiation of cells into stalk cells occurred at the rear of cell masses.

Structural alteration and destructive corneal disease.

There is good evidence that maintenance of the structural integrity of the human cornea carries with it significant advantages over and above the preservation of normal function. The breakdown in the protective layers of the cornea and invasion by blood vessels and lymphatics would seem to add greatly to the risk of recurrent inflammatory disease. There is a solid rationale, therefore, for the development of therapeutic principles aimed at preventing these structural changes from occurring.

RNA and protein synthetic patterns during germination of Polysphondylium pallidum microcysts.

During microcyst germination in the cellular slime mould Polysphondylium pallidum, an immediate rapid increase in the rate of protein synthesis ([3H]leucine incorporation) is observed within 15 min after the initiation of germination. The data, corrected for amino acid pool changes, reveal that the rate of protein synthesis reaches its peak at 1 1/2 h, after which it decreases. A low level of RNA synthesis ([3H]uridine incorporation) is observed after 1 h and this rate increases markedly after 2 h.

Sexual hormone in the cellular slime mould Dictyostelium purpureum.

The existence of sexual hormone in Dictyostelium purpureum was revealed when the extracelluar medium from certain strains (Dp6 or Dp7) induced macrocyst formation when added to cells of the opposite mating type (Dp2). Our results suggest that mating in cellular slime moulds may involve a secreter-responder system whereby one mating-type strain (Dp6 or Dp7) releases sexual hormone while the opposite strain (Dp2) responds. However, the existence of a hormone released by the responding strain has not been completely ruled out by our experiments.

Vidarabine therapy of complicated herpes simplex keratitis.

Patients with active herpetic epithelial keratitis who had toxic reactions or were resistant to idoxuridine received vidarabine. Only one of 35 cases of herpetic epithelial keratitis without stromal disease failed to heal. Of 21 patients with active epithelial keratitis complicating stromal keratitis or uveitis.

Clinical and laboratory evaluation of epidemic keratoconjunctivitis due to adenovirus types 8 and 19.

During a community outbreak of epidemic keratoconjunctivitis due to adenovirus types 8 and 19, we compared the clinical and laboratory characteristics of the two viruses. Much of the disease was mild and the keratoconjunctivitis associated with adenovirus type 8 was indistinguishable clinically from that associated with adenovirus type 19. Adenovirus type 8 was isolated only from the conjunctival sac, whereas adenovirus type 19 was frequently cultured from the nose, throat, and conjunctiva.

Acid protease activity during germination of microcysts of the cellular slime mold Polysphondylium pallidum.

Extracts of dormant microcysts of Polysphondylium pallidum demonstrate pH optima for the hydrolysis of casein at 3.5 and 6.0.

Epidemic keratoconjunctivitis: a community outbreak of mixed adenovirus type 8 and type 19 infection.

During the fall and winter of 1973, 145 cases of epidemic keratoconjunctivitis were diagnosed in Nashville, Tennessee. Of the 74 cases studied virologically and/or serologically, 62% were caused by adenovirus type 8, and 28% were caused by adenovirus 19. Whereas adenovirus type 8 was isolated only from conjunctival scrapings, adenovirus type 19 was isolated from nose and throat swabs as well as from conjunctivae.

Proflavine photodynamic viral inactivation in herpes simplex keratitis.

We used the photodynamic inactivation technique with proflavine as the photoactive dye to treat herpetic epithelial keratitis in a preliminary study of patients who had idoxuridine toxicity or resistance. A comparative study with idoxuridine in treating dendritic ulcerations of the cornea showed a good therapeutic effect. But the investigation was suspended when adverse reactions, consisting of a generalized epithelial keratitis and an anterior uveitis, possibly of phototoxic origin, developed in a few patients receiving treatment.