Otosyphilis and hearing loss: response to penicillin and steroid therapy.

Acquired and congenital syphilis are both known causes of potentially reversible sensorineural hearing loss. Various therapeutic regimens, including penicillin and/or corticosteroids have been used in the past as treatment for otosyphilis. Response rates have varied from 15% to 80%. In this retrospective study, 13 patients with otosyphilis were treated with a combined course of long-term penicillin and prednisone. A significant response was defined as a 15% improvement in the discrimination score and/or the pure tone average. Initial response rates were 35% with a lasting response rate of 15%. Discrimination scores improved more commonly than pure tone averages. No patient with congenital syphilis or profound deafness had a lasting response. An analysis of possible reasons for failure of therapy is discussed.

Impaired renal and extrarenal potassium adaptation in old rats.

Young (3 to 4 months) and old (21 to 22 months) rats were fed either a regular or high potassium (K) diet. After acute potassium chloride infusion, the fraction of infused K excreted (K efficiency) was similar in rats on a normal diet (57 +/- 3%, young, vs. 61 +/- 2%, old). With high K feeding there was a significant increase in the young, 69 +/- 4%, but not in the old rats, 62 +/- 2%. Na-K ATPase activity was markedly reduced in the renal medulla of old rats on a regular or high K diet. In addition, the response to acute K loading was compared in acutely nephrectomized rats. In the young rats on a regular diet plasma K increased from 3.72 +/- 0.09 to 5.28 +/- 0.16 mEq/liter while with K ingestion the increase was significantly less, 3.62 +/- 0.07 to 4.75 +/- 0.12 mEq/liter. In the old rats plasma K increased similarly on a regular or high K diet, 3.68 +/- 0.10 to 5.68 +/- 0.33 mEq/liter and 3.76 +/- 0.06 to 5.97 +/- 0.30 mEq/liter, respectively. Thus, old rats have impaired renal and extrarenal adaptation, but they have a normal response to an acute K challenge. A reduction in Na-K ATPase may account for the defect in renal adaptation in the aged rats.

Urinary concentrating defect in the aged rat.

The renal concentrating ability of Fischer 344 rats was studied at 23 and 4 mo of age. Maximum urine concentration after 40 h of dehydration with or without vasopressin injection was significantly lower (P less than 0.01) in old (2,550 +/- 70 and 2,363 +/- 107 mosmol/kg H2O2, respectively) vs. young (3,242 +/- 50 and 3,162 +/- 50 mosmol/kg H2O, respectively) rats. Free water reabsorption (TcH2O/GFR) rose progressively as a function of osmolar clearance, and at similar values of distal solute delivery TcH2O was clearly reduced in the old group. Free water formation (CH2O/GFR) rose linearly as a function of urine flow and was not different between old and young rats. Glomerular filtration rate was also not different between age groups under the conditions studied. Nonurea (sodium + potassium + ammonium) x 2 and urea solute concentrations as well as total calculated osmolality in the cortex, outer medulla, or inner medulla were not different between age groups. Because the indices of ascending limb solute delivery and transport and the solute gradient for water reabsorption were similar, we conclude that the concentrating defect in aged rats is most likely secondary to a decrease in water permeability along the collecting duct.

Boll weevil eradication.

Some representatives of the cotton industry and of the entomological profession advocate efforts to eradicate the boll weevil. This coalition originated in 1958 from a complex of socioeconomic changes in cotton production and scientific developments in entomology. The results of a pilot eradication experiment (1971 to 1973) were controversial, and the debate was inhibited by social pressures upon the entomological profession. Substantial conceptual difficulties also attend evaluations of eradication experiments. A new trial eradication program is under way. If its evaluation is not to be warped by problems similar to the earlier ones, both the social and scientific aspects of eradication must be recognized and steps must be taken to ensure a full and open debate.

Stapedectomy: gelfoam compared with tissue grafts.

The commonest causes of failure with the prefabricated wire loop-gel foam pad technique are inferior displacement of the loop in the window, high membrane formation and window fibrosis. As a result of these problems some members of the Otologic Medical Group have abandoned the use of gelfoam in favor of tissue grafts. A comparison of the results with gelfoam, fat grafts, and fascia grafts in 573 primary cases is made. Tissue grafts yielded a lower incidence of postoperative vertigo, of temporary and permanent sensori-neural hearing impairment, of fistulas and of long-term hearing regression. The conclusion is that a tissue graft is preferable to gelfoam as an oval window covering in stapedectomy.

Morphogenesis in Schizophyllum commune. I. Effects of white light.

Reproductive differentiation in the basidiomycete Schizophyllum commune Fr. is initiated by plasmogamy and reciprocal nuclear migration and is terminated by the production of basidiospores. The work reported here has analyzed several factors that affect 2 sequential steps in reproductive differentiation: A) the formation of aggregated masses of cells, and B) the subsequent differentiation of fruiting bodies. The 2 steps are both photosensitive: A) light accelerates the formation of aggregated masses of cells; B) a short exposure of light induces nonaggregated dikaryotic cells to form mature fruiting bodies in the dark. Cultures of dikaryotic mycelia showed little or no response to light during approximately the first 60 hr of growth. Subsequent to this time, they were photosensitive. Several properties of the photoinduction of fruiting bodies were established in studies utilizing white fluorescent light. (1) The morphogenetic response (fruiting) was approximately linear with the amount of light delivered at low intensities; higher intensities elicited no further response. (2) The photoresponse did not vary when replicate cultures were irradiated at temperatures of 2 degrees , 24 degrees , or 35 degrees . (3) The induction of fruiting bodies by light is disrupted by post-induction heat-exposures of 50 degrees for 1 hr or longer. (4) Photoinduced fruiting bodies formed in distinctive rings on the mycelia and thus suggested that cells of different ages differ in their ability to be photoinduced.

Morphogenesis in Schizophyllum commune. II. Effects of monochromatic light.

The photoinduction of fruiting bodies by light of defined wavelengths was studied in the fungus Schizophyllum commune Fr. Several properties of the induction were established. (1) The exposure-response relationship for induced fruiting was determined for light of 448 nm. (2) The Bunsen-Roscoe Law of Reciprocity was found to hold for the photoinduction of fruiting bodies for the interval 36 to 2000 sec with light of 448 nm. (3) Light of wavelengths from 320 nm to 525 nm induced fruiting bodies. Although the photoreceptor is unknown, it may be a flavin rather than a carotenoid, because light in the near ultraviolet (350 nm-400 nm) was inductive. (4) Neither red light (660 nm) nor far-red light (730 nm) induced fruiting bodies or affected the sensitivity of the fungus toward photoinduction by blue light (448 nm).