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Biomedical subjects

G J McGrath

Publications and source records attributed to G J McGrath.

6 recordsLinked to original sources
PubMed1999

Asymptomatic dermatophyte carriers in the households of children with tinea capitis.

OBJECTIVES: To determine the prevalence of the carrier state in household contacts in children with tinea capitis, the duration of the carrier state, factors associated with carriage, and the proportion of carriers who develop clinical disease. DESIGN: Cross-sectional, cohort, prevalence study. SETTING: General pediatric clinic serving an indigent, inner-city, African American population. PATIENTS: Household contacts in children with tinea capitis. Index cases and carriers (no clinical evidence of infection) were identified by culture. Carriers were monitored until the results of their culture became negative, they developed clinical disease, or a 6-month period had elapsed. RESULTS: Fifty-six index cases and 114 contacts (50 adults and 64 children) were evaluated. Ninety-eight percent of the dermatophytes identified in index cases and 100% in carriers were Trichophyton tonsurans. At the initial visit, 18 (16%) of 114 (95% confidence interval [95% CI], 10-24) of contacts were carriers and 14 (32%) of 44 of the families studied had at least 1 carrier. At the 2-, 4-, and 6-month visits, the carrier state persisted in 7 (41%) of 17 (95% CI, 19-67), 3 (20%) of 15 (95% CI, 4-48), and 2 (13%) of 15 (95% CI, 2-40), respectively. Three of the carriers were lost to follow-up. Of the carriers, 1 (7%) of 15 (95% CI, 0.2-32) developed tinea capitis. Univariate and multivariate analysis showed no association of carrier state to age, sex, comb sharing, or cosleeping. However, cosleeping and comb sharing were common among the contacts, occurring 75% and 78% of the time, respectively, making statistical correlation difficult with our sample size. CONCLUSIONS: Initial prevalence of asymptomatic carriage of dermatophytes among household contacts of a child with tinea capitis was 16%, with 41% of carriers persisting up to 2 months. Thirty-two percent of families had at least 1 member who was a carrier. Seven percent of the carriers developed an active infection. Treatment of carriers with sporicidal shampoo should be considered since they may act as a reservoir for infection or develop active disease. The high prevalence of cosleeping and comb sharing may be important factors in the spread of the disease.

Adult↗
PubMed1997

Physical findings and symptoms of depot medroxyprogesterone acetate use in adolescent females.

STUDY OBJECTIVE: To document physical and symptomatic changes in adolescent females using depot medroxyprogesterone acetate (DMPA) for contraception. DESIGN: A 30-month prospective experimental study using a convenience sample of subjects. SETTING: A pediatric primary care clinic in Milwaukee, Wisconsin that serves an urban population of low socioeconomic status. PARTICIPANTS: A mostly African-American group of 53 patients (mean age 16.5 +/- 1.3 years). INTERVENTIONS: Subjects received 150 mg DMPA intramuscularly in either the deltoid or gluteus muscle. The first two DMPA injections were given 6-8 weeks apart in an effort to decrease menstrual irregularity. Subsequent injections were given every 3 months. A questionnaire was administered at each visit to document physical and symptomatic changes. MAIN OUTCOME MEASURES: Included weight change, frequency and amount of menstrual bleeding, and perceived side effects and satisfaction both documented with a 5-point Likert scale. RESULTS: At 5, 11, and 17 months of DMPA use, 75%, 40%, and 19% of subjects continued DMPA. The most commonly perceived side effects were weight gain (27%), headache (25%), irregular periods (24%), fatigue (23%), abdominal pain (18%), and decreased sexual desire (15%). Significant weight gain was noted with an average increase of 6.0 +/- 6.0 kg at 11 months of DMPA use and 9.0 +/- 5.4 kg at 17 months. No menstrual bleeding was experienced by 30%-40% of adolescents in any 3-month injection period, and those who bled averaged 8-13 days of bleeding between injections. No pregnancies occurred and 87% of patients were either satisfied or very satisfied with DMPA as a method of contraception. CONCLUSION: Despite the documented side effects, DMPA is an effective, acceptable contraceptive for some adolescent females who are at high risk for pregnancy.

Adolescent↗
PubMed1973

Evidence from the use of vibration during procaine nerve block that the spindle group II fibres contribute excitation to the tonic stretch reflex of the decerebrate cat.

1. Experiments have been performed to test the hypothesis that the group II fibres from the secondary endings of the muscle spindle provide an excitatory contribution to the tonic stretch reflex of the decerebrate cat. They have consisted of studying the effect of fusimotor paralysis by procaine, applied to the muscle nerve, on the reflex response to the combined stimuli of stretch (5-9 mm at 5 mm/sec) and of high-frequency vibration (100-150 Hz, 150 mum).2. The reflex response to the combined stimuli was found to be paralysed in two distinct stages which paralleled those of the ordinary stretch reflex described earlier. The two phases of paralysis may be attributed to an early paralysis of the gamma efferents followed by a later paralysis of the Ia afferents and alpha motor fibres. However, the Ia discharges elicited by the combined stimuli, unlike those elicited by simple stretch, should have remained unchanged on gamma efferent paralysis since the Ia firing frequency may be presumed to have been clamped at the vibration frequency by the occurrence of one-to-one ;driving'. The early reduction of the response to the combined stimuli may thus be attributed to the removal of a stretchevoked autogenetic excitatory input other than that long known to be provided by the Ia pathway. This supports the view that the spindle group II fibres have such an action, since their firing will be appropriately reduced on gamma efferent paralysis by removal of their pre-existing fusimotor bias; there is no evidence for the existence of any other group of fibres with the right properties.3. Recording of compound action potentials and of single units confirmed the great sensitivity of the gamma efferents to procaine but showed that the group II fibres were nearly as resistant as the Ia fibres and alpha motor fibres.4. The reliability of one-to-one driving of the Ia discharges by the vibration was tested in control experiments in which the reflex was elicited by an asymmetrical vibratory waveform with a rapid rising phase (1.5 or 1.9 msec at 140 Hz) and a slower falling phase. Recordings from single units showed that the use of this wave form greatly diminished any tendency to double driving (2 spikes/cycle of vibration) during the dynamic phase of stretch and never elicited it during the static phase of stretch when the reflex measurements were made. These ;pulsed' vibrations elicited reflex contractions which were of the same general size and which were paralysed in the same two phases by procaine as those elicited by sinusoidal vibrations. This eliminates the possibility that the early phase of paralysis might have been due to conversion of the pattern of Ia firing from double to single driving on gamma efferent paralysis.5. Wedensky inhibition of the afferent fibres could not be held responsible for the early phase of paralysis.6. The results are taken to strengthen the hypothesis that the spindle group II fibres contribute excitation rather than inhibition to the stretch reflex. The particular support derived from the present experiments is that all measurements of the size of the reflex at various times were made with the muscle at the same length so that the findings cannot be attributed to the tension-length properties of muscle. The detailed mechanism of the excitation, however, remains to be established and certain of the present findings suggest that it may not be a direct one.

Action Potentials↗