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Biomedical subjects

C Wolters

Publications and source records attributed to C Wolters.

5 recordsLinked to original sources

Early and longitudinal evaluations of treated infants and children and untreated historical patients with congenital toxoplasmosis: the Chicago Collaborative Treatment Trial.

Between December 1981 and May 1991, 44 infants and children with congenital toxoplasmosis were referred to our study group. A uniform approach to evaluation and therapy was developed and is described herein along with the clinical characteristics of these infants and children. In addition, case histories that illustrate especially important clinical features or previously undescribed findings are presented. Factors that contributed to the more severe disabilities included delayed diagnosis and initiation of therapy; prolonged, concomitant neonatal hypoxia and hypoglycemia; profound visual impairment; and prolonged, uncorrected increased intracranial pressure with hydrocephalus and compression of the brain. Years after therapy was discontinued, three children developed new retinal lesions (without loss of visual acuity when therapy for Toxoplasma gondii was initiated promptly), and three children experienced a new onset of afebrile seizures. Most remarkable were the normal developmental, neurological, and ophthalmologic findings at the early follow-up evaluations of many--but not all--of the treated children despite severe manifestations, such as substantial systemic disease, hydrocephalus, microcephalus, multiple intracranial calcifications, and extensive macular destruction detected at birth. These favorable outcomes contrast markedly with outcomes reported previously for children with congenital toxoplasmosis who were untreated or treated for only 1 month.

Animals

Hearing loss in children with Down syndrome.

Conventional behavioral testing of hearing shows that children with Down syndrome have a high prevalence of hearing deficits. However, most young (< 3.5 years of age) children with Down syndrome are unable to cooperate in this type of testing. We evaluated auditory brain-stem responses of 47 unselected patients 2 months to 3 1/2 years of age. Thirty-four percent had normal hearing, 28% had unilateral loss, and 38% had bilateral loss. Type of loss was conductive in 19 ears, mixed in 14, and sensorineural in 16. Degree of loss was mild in 33 ears, moderate in 13, and severe to profound in 3. Language quotients and degree of hearing loss were compared and an association was not found. Because of the high prevalence of hearing loss in children with Down syndrome, we recommend evaluation of auditory brain-stem responses in the first 6 months of life.

Acoustic Impedance Tests

Absence of sensorineural hearing loss in treated infants and children with congenital toxoplasmosis.

Educationally significant hearing loss has been reported in 10% to 15% of children with congenital toxoplasmosis. As part of a pilot study to assess feasibility and safety of prolonged therapy for congenital toxoplasmosis, 30 congenitally infected infants and children were evaluated for auditory function. Serial testing, beginning within 2 months of birth, was performed. Availability of auditory brainstem response (ABR) testing made evaluation at an earlier age than previously possible. Six (20%) of the 30 infants had mild to moderate conductive type hearing loss associated with otitis media. No infant or child had sensorineural hearing loss. The better outcome we observed compared to previous reports of a 15% to 26% incidence of sensorineural hearing loss and 10% to 15% incidence of educationally significant, bilateral hearing impairment may be related to early initiation and/or prolonged institution of antimicrobial therapy. Continued followup to exclude progressive hearing impairment and study of larger numbers of children are needed to verify these preliminary findings.

Audiometry, Evoked Response

Viewing the audiogram through a mathematical model.

In an effort to better quantify audiometric results, audiograms were modeled with a hyperbolic tangent function of the form: t = a tanh [(f-c)/b] + d, where t = threshold and f = frequency. The parameters, a, b, c, and d, were determined for a specific audiogram via a least-squares nonlinear curve fitting technique. The parameters describe salient features of the audiogram. The point (c,d) is the midpoint of the sloping portion of the audiogram, while a and b describe the slope. Other features of the configuration can be described by combinations of the parameters. This approach quantifies the entire audiogram and allows simple correlations of routinely gathered clinical data. To demonstrate the application of the model, a small data set of 500 Hz ABR and behavioral thresholds recorded from 28 ears (23 subjects) was analyzed. The model showed that agreement between the thresholds varied with audiometric configuration.

Adolescent

Therapeutic regimen of septic vascular complications in kidney grafting.

In spite of highly sophisticated tissue matching reducing immunogenicity of a graft a high degree of immunosuppression is mandatory to achieve good graft survival. Septic complications such as a rupture of an anastomosis threaten the recipients life. Thorough donor selection, strict asepsis, as well as repeated bacteriologic examination gives the chance to decrease morbidity and mortality of kidney grafting. In the retrospective analysis of 135 kidney transplantations septic vascular complications occurred in 3.7%. The surgical procedure of choice after graft removal is the ligation of the external iliac artery. Only in one out of four cases ischemia of the lower extremity had to be treated by an extra-anatomic femoro-femoral bypass.

Adult