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Biomedical subjects

E Foltz

Publications and source records attributed to E Foltz.

7 recordsLinked to original sources
PubMed1985

Auditory brainstem response in infant hydrocephalus.

Fifteen infants with hydrocephalus ranging in age from 32 to 43 weeks from conception were studied. The auditory brainstem response (ABR) was measured 48 h prior to the placement of a CSF shunt and within 5 days following shunt insertion. Results of this study showed a general improvement in the ABR following placement of the shunt. No consistent patterns were observed that allowed a clear explanation of the cause and effect of the abnormal ABR. However, the changes seen in the ABR are caused by increased CSF pressure, which may compress the transmission fibers, and generators of the ABR producing a type of neuropraxis. Early shunting appears to have a better outcome on the ABR than later shunting.

Auditory Threshold↗
PubMed1984

Intracranial pressure effects on auditory evoked responses in the rabbit: preliminary report.

Acute elevated intracranial pressure (ICP) effects on the auditory evoked response (AER) were studied in the rabbit. Simultaneous CSF infusions to increase ICP and contralateral ICP pressure recordings were done through bilateral ventriculostomies. During rarefaction auditory stimulation, a minicomputer obtained a time-locked AER from ongoing electroencephalographic activity at base line ICP mean pressure and at three levels of increased ICP (250, 500, and 700 mm CSF) above base line. The results showed a statistically significant increased latency of the N3-P3 portion of the AER as well as of the P1-P3 central conduction time. The amplitude of AERs appeared unchanged. The effect is reversible and presumably is a neuropraxic type pressure effect on brain stem auditory pathways. Its clinical relevance is discussed.

Acoustic Stimulation↗
PubMed1984

Experimental transcerebral fistula. Perineural olfactory CSF flow in the normal, hydrocephalic, and postoperative hydrocephalic dog shown by radionuclide ventriculography.

Cerebrospinal fluid dynamics were studied in eight dogs during normal, hydrocephalic, and postoperative phases. Radionuclide-labeled substances introduced into the normal ventricular system flow out of the exits from the fourth ventricle to the convexity subarachnoid spaces superiorly to be absorbed in the sagittal sinus, and basorostrally to the exits from the perineural olfactory sheath into the nose to produce physiological cerebrospinal fluid (CSF) rhinorrhea. Serial radionuclide ventriculography of the head following intraventricular isotope injection of labeled proteins and chelate into the kaolin-induced hydrocephalic system shows a high degree of ventricular stasis with no perineural olfactory nerve flow (rhinorrhea). An operative transcerebral fistula, fashioned from a dilated lateral ventricle to the convexity subarachnoid space, reestablishes perineural olfactory flow of CSF into the nose, as demonstrated by the radionuclide ventriculography studies. This suggests a potential method for treatment of hydrocephalus. Serial imaging studies in this surgically modified system clearly demonstrate radionuclide flow through the patent fistula to distal absorption sites, thereby bypassing the basal obstruction. Moreover, augmented CSF pressures associated with obstructive hydrocephalus can be controlled by such treatment. The application of this method in treating clinical hydrocephalus is discussed with emphasis on fistula arachnoid closure to assure fistula patency.

Animals↗
PubMed1979

Acute effects of aminoglutethimide on testicular steroidogenesis in normal men.

Aminoglutethimide (AG), a known adrenal inhibitor, was administered acutely to normal men in order to study its effects on testicular steroidogenesis. Sixteen subjects between the ages of 21--30 yr received either placebo or 1250 mg AG in divided doses during a 24-h period. To reduce the contribution of adrenal steroids, adrenal function was inhibited in both groups of men by the administration of dexamethasone (2 mg) on the night of the experiment. As a result, mean morning plasma cortisol levels fell to less than 2 micrograms/100 ml. AG blunted the normal diurnal rise in testosterone, which was observed in men receiving placebo, and significantly suppressed the levels of this androgen at 0700 and 0900 h. Estradiol concentrations fell to a greater extent than those of testosterone. The differences between the placebo and drug treatment groups were significant at all time points except 1900 h. A pattern similar to that of estradiol was observed for plasma estrone. When the overall effect of AG administration was examined by analysis of variance, the differences in the levels of all three steroids produced by treatment were highly significant (P less than 0.01 to less than 0.001). After the inhibition of testosterone and estradiol levels, LH and FSH concentrations were significantly (P less than 0.01 and P less than 0.001, respectively) higher in men receiving AG than in those given placebo. However, the data exhibited a large variance due to pulsatile gonadotropin secretion. These observations suggested that AG induces an acute inhibition of testicular steroidogenesis and probably also of the aromatization of testosterone to estradiol.

Adult↗
PubMed1976

Hydrocephalus: possible role of an internal cerebrospinal fluid fistula in therapy.

Transfer of cerebrospinal fluid from the lateral ventricle transcerebrally to the distal subarachnoid space was performed in the hydrocephalic dog. These fistulae were formed with the aid of a small suction tip and the operating microscope. Clinical evaluation of the dogs was made daily until sacrifice at four to six weeks. Documentation of the clinical course and ventricular size of the shunted and control animals was made. The studies indicate that the microsurgically produced fistulae may be an effective form of treatment in the hydrocephalic animal.

Animals↗