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Biomedical subjects

W R Wilson

Publications and source records attributed to W R Wilson.

At least 289 records · Page 16Linked to original sources
PubMed1981

Toxicity of 4'-(9-acridinylamino)methanesulfon-m-anisidide in exponential- and plateau-phase Chinese hamster cell cultures.

The antitumor acridine derivative 4'-(9-acridinylamino)methanesulfon-m-anisidide (m-AMSA) is at present being evaluated in Phase 2 clinical trials. Exposure of exponential-phase Chinese hamster V79-171b cells to physiologically attainable concentrations of m-AMSA for 60 min generates survival curves with little or no threshold region and an initial D0 of 0.245 +/- 0.019 (S.D.) microM under standard conditions of assay. A minor subpopulation of apparently drug-resistant cells is revealed at low survivals, but these cells on culturing do not display a stable drug-resistant phenotype. m-AMSA survival curves for Chinese hamster ovary cells display features similar to the above. Sensitivity of V79-171b cells to m-AMSA is maximal near pH 7.2 and is markedly reduced by the presence of fetal calf serum. Hypoxia has little effect on the toxicity of m-AMSA, and repair of potentially lethal damage has not been observed after treatment with this agent. Noncycling plateau-phase V79-171b or Chinese hamster ovary cells are markedly less sensitive to m-AMSA than are early log-phase cells. This resistance to m-AMSA appears to be related to the slowly cycling or noncycling status of plateau-phase cells, suggesting that the cytokinetic character of cell populations in vivo will be a major determinant of their sensitivity to this drug. However, the increase in resistance to m-AMSA during growth into plateau-phase appears to commence well before departure from exponential growth can be detected and may thus be a consequence of metabolic changes more subtle than the transition from a cycling to a noncycling state.

Aminoacridines↗
PubMed1981

Activity of 4'-(9-acridinylamino)methanesulfon-m-anisidide against Chinese hamster cells in multicellular spheroids.

The cytotoxic activity of 4'-(9-acridinylamino)methanesulfon-m-anisidide (m-AMSA), a novel acridine derivative with clinical antitumor activity, has been examined in multicellular spheroids grown from Chinese hamster V79-171b cells. m-AMSA is much less effective against cells within these tumor-like structures than it is against exponential-phase V79-171b cells in monolayer cultures, the initial D0 of the survival curve for the latter being approximately 10-fold lower than for the former following a 60-min exposure to the drug. The resistance of spheroid cells to m-AMSA appears to be at least partially a result of the noncycling or slowly cycling state of the majority of these cells, although they are more sensitive than cells in plateau-phase monolayers. A further component of resistance in spheroids requires the presence of an intact spheroid structure and may be due to drug transport limitations. The use of sequential trypsinization techniques to recover cells at varying depths within spheroids demonstrates that a 60-min m-AMSA treatment preferentially kills cells nearest the spheroid surface, suggesting that tumor cells at a distance from the vasculature may limit the efficacy of m-AMSA in vivo.

Aminoacridines↗
PubMed1980

The efficacy of steroids in the treatment of idiopathic sudden hearing loss. A double-blind clinical study.

Double-blind studies were conducted for the treatment of idiopathic sudden hearing loss (ISHL) with oral steroids. The condition was defined as not less than a 30-dB loss over three contiguous frequencies in three days or less. Follow-up audiograms were obtained four weeks and three months later. Specific audiologic guidelines for the assessment of hearing recovery were used to ensure objectivity. Steroids had a statistically significant effect on the recovery of hearing in patients with moderate hearing losses. The nature of the hearing loss and its susceptibility to improvement with steroid therapy lend support to the hypothesis that viral cochlitis is the primary cause of ISHL.

Adult↗
PubMed1980

Synergy of penicillin and decreasing concentration of aminoglycosides against enterococci from patients with infective endocarditis.

To determine whether low concentrations of aminoglycosides in combination with penicillin could effectively kill enterococci in vitro, we tested penicillin (20 micrograms/ml) in combination with decreasing concentrations of either streptomycin (20, 10, 5, and 1 micrograms/ml) or gentamicin (5, 3, 1, and 0.5 micrograms/ml) against 13 strains of streptomycin-susceptible and 7 strains of streptomycin-resistant enterococci isolated from patients with infective endocarditis. At 24 h, penicillin plus each increment in streptomycin concentration resulted in a statistically significant increase in killing of streptomycin-susceptible enterococci, compared with the next lower streptomycin concentration (P less than 0.01). At 24 h, against streptomycin-susceptible and streptomycin-resistant enterococci, there were no statistically significant differences in killing between combinations containing 5 micrograms of gentamicin per ml and those containing 3 micrograms/ml. Against streptomycin-susceptible enterococci, there were statistically significant differences in killing between combinations containing 3 micrograms of gentamicin per ml and those containing 1 micrograms/ml. Against streptomycin-resistant enterococci, statistically significant differences in killing were detected with combinations containing 5 micrograms of gentamicin per ml and those containing 1 microgram/ml.

Drug Synergism↗
PubMed1980

Recurrent parotitis during childhood.

A case of a child suffering from recurrent parotitis secondary to inadvertant chewing on Stensen's duct orifice suggests that this cause may be common to other children plagued by this puzzling disorder.

Cheek↗
PubMed1980

Visceral leishmaniasis (kala-azar) as a cause of fever of unknown origin.

A patient with a rare cause of fever of unknown origin, visceral leishmaniasis (kala-azar), is reported. The diagnosis was made by exploratory laparotomy and splenectomy after diagnostic studies had failed to reveal the cause of the fever. The patient was cured with a 6-day course of therapy with Pentostam (sodium antimony gluconate). Visceral leishmaniasis should be considered in the differential diagnosis of patients with obscure fever who have traveled in endemic areas.

Adult↗
PubMed1980

Update on the use of streptomycin therapy for Meniere's disease.

An update of our experiences in the treatment of Meniere's disease with intramuscular streptomycin sulfate reveals great success in relief of episodic vertigo. Hearing losses that existed before the treatment are generally stabilized and occasionally improved. Because of the considerable morbidity caused by arduous therapy, prolonged ataxia, and occasional oscillopsia, we recommend that the treatment be reserved for the bilateral disabling form of the disease.

Adult↗
PubMed1980

Effects of early linguistic experience on speech discrimination by infants: a reply.

This paper is a reply to a critique of Eilers, Gavin, and Wilson (1979) by Aslin and Pisoni (this issue). The reply argues that the critics' contentions are basically unwarranted on both methodological and conceptual grounds. The critique is largely based on misunderstandings of the study's purposes and procedures.

Discrimination Learning↗
PubMed1980

Infective endocarditis caused by Actinobacillus actinomycetemcomitans: report of four cases.

Four patients with infective endocarditis caused by Actinobacillus actinomycetemcomitans are reported. The clinical course was characterized by chronicity. Three of the four patients were treated with combined penicillin and aminoglycoside therapy on an empiric basis; the fourth patient was given ampicillin alone for 3 weeks. Cure was achieved in all four cases, with antibiotic therapy alone in the first three and ampicillin alone plus valve replacement surgery in the fourth patient. Further in vitro bactericidal data are needed, and actual therapy with ampicillin alone is desirable to see whether these patients with endocarditis of natural valves cannot be treated with ampicillin alone for a 3-week period.

Actinobacillus Infections↗
PubMed1980

Toxic shock syndrome, a newly recognized disease entity. Report of 11 cases.

The toxic shock syndrome has only recently been described. Eleven female patients aged 13 to 43 years (median 17) with toxic shock syndrome have been seen at the Mayo Clinic since August 1975. One patient died. Seven patients had one or more recurrences. As previously described, the syndrome was often life-threatening, afflicted mostly menstruating females, and was characterized by a very brief prodromal illness consisting of high fever, vomiting, diarrhea, conjunctivitis, headache, irritability, sore throat, myalgias, abdominal tenderness, and erythematous rash. The disorder can progress to hypotension or prolonged refractory shock, adult respiratory distress syndrome, diffuse intravascular coagulation with severe thrombocytopenia, and renal failure. Pancreatitis was observed in two cases. During convalescence, pronounced desquamation and peeling of the skin occurred. Numerous laboratory abnormalities are observed. In 5 of the 11 patients, Staphylococcus aureus was isolated from conjunctiva, oral cavity or nares, vagina, or stool. A recently described pyrogenic exotoxin was identified in the isolates of three patients; its etiologic role remains speculative. Therapy is mainly supportive. Antistaphylococcal therapy for the acute illness and for prevention of recurrences has not yet proved to be of any benefit. The role of vaginal tampons, if any, in the pathogenesis of this disorder remains unclear.

Adolescent↗
PubMed1979

Application of visual reinforcement audiometry (VRA) to low-functioning children.

Visual reinforcement audiometry (VRA) was studied on a group of low-functioning children in an ongoing clinical program. After establishing the specific reinforcing value of the visual stimulus, threshold assessments were made. VRA was an effective test procedure for most of the children tested, providing their developmental ages reached approximately the 10-month level or higher. On the basis of VRA thresholds and tympanometry, 52% of the children seen were referred for medical evaluation. A variation of VRA was used to assess syllable-discrimination performance on a pilot basis. Results are discussed in terms of the potential use of VRA to assess infant spedch-sound discrimination in addition to its current use as an indicator of hearing sensitivity.

Audiometry↗