Further differences between brain-stem auditory potentials evoked by rarefaction and condensation clicks as revealed by vector analysis

Vectorial analysis of the brain-stem auditory evoked potential (BAEP) elicited by either condensation and rarefaction stimuli was performed in 22 healthy subjects. Besides differences in latency of components III and V ('R' longer than 'C'), a significant difference was found between the directions of the vector calculated over the descending limb of wave III, with an ascending direction for 'C' responses and a contralateral direction for 'R' responses. The possible origins of these differences are discussed. It is concluded that the use of alternating or isolated single polarity clicks is not recommended, mainly when assessing integrity of central auditory pathways.

Presence of a membrane bound pyroglutamyl amino peptidase degrading thyrotropin releasing hormone in rat brain

In the present work we studied the pattern of degradation of [3H-Pro]-TRH by soluble and membrane fractions from rat brain. Demonstration of the membrane bound or soluble nature of the activities was obtained by comparing their distribution to that of lactate dehydrogenase and by looking at the effect of NaCl washes on the membrane fractions. We observed that the pyroglutamyl amino peptidase activity detected in brain homogenates is a result of two different enzymes. One of them is a soluble enzyme previously characterized, that needs DTT and EDTA for its expression, is inhibited by SH-blocking agents such as iodoacetamide and utilizes p-glu-beta-naphtylamide as a substrate. The other one, a membrane enzyme, is inhibited by chelating agents such as EDTA and DTT, is not affected by iodoacetamide and does not degrade p-glu-beta-naphtylamide. The later presents some specificity towards TRH as shown by competition experiments with TRH analogs. We were able to corroborate that the post proline cleaving enzyme acting on TRH is a soluble enzyme. In membranes we demonstrated also the presence of a post-proline dipeptidyl aminopeptidase. The membrane bound pyroglutamidase activity is a potential new source of L-his-L-pro-diketopiperazine in brain. The presence of a TRH degrading enzyme in membrane fractions is of particular importance in searching an inactivation mechanism of this peptide once it is released into the synaptic cleft.

Scoliosis secondary to fractures of the transverse processes of lumbar vertebrae

Fractures of the transverse processes of the lumbar vertebrae may be difficult to identify radiographically because they are often obscured by gas and feces. With unilateral fractures, there is often scoliosis convex to the side of the fractures. We propose that this may be due to the ineffective action of the ipsilateral quadratus lumborum muscle which inserts into the transverse processes. The unopposed action of the contralateral quadratus lumborum results in scoliosis convex to the side of the fracture(s). Awareness of this cause of scoliosis can help in differentiating it from scoliosis caused by other painful abdominal processes, and may aid in recognition of the fracture(s).

Treatment of South American blastomycosis (paracoccidioidomycosis) with miconazole by the oral route: an on-going study

Results are presented from 12 patients of both sexes, whose ages range from 34 to 65 years, observed over a period of 16 months and receiving miconazole treatment for South-American blastomycosis. Ten of them were being treated for the first time and the remaining 2 presented relapses after treatment with other chemotherapeutic agents. The blastomycotic lesions were localized in skin, mucosa, lung and lymphatics. The drug was administered orally, at a dosage of 1 g three times daily. One relapsing patient had his first daily oral dose replaced by an intravenous dose of 200 mg of miconazole diluted in 250 ml of glucose solution during the initial four weeks. The criterion for diagnosis was finding of the fungus in sputum and/or in the material collected through scrapings or biopsy of the lesions. All patients were treated in hospital until the cure was apparent, clinical examinations being conducted weekly and bi-weekly. Bi-weekly laboratory examinations were performed to evaluate the patient's tolerance to the drug. All treated patients presented complete healing of cutaneomucous lesions (mean time: 4 weeks) and involution of lymphatic and pulmonary features (mean time: 4 months). Two of them still presented palpable lymphatics after 5 months of treatment, in spite of the cure of mucosal and pulmonary lesions. Monitoring the progress of the cured patients was and is being carried out quarterly. Currently, this observation period ranges from three to 15 months. Nine patients are still returning and none have shown the reappearance of mycotic lesions. Diarrhoea was the only side-effect observed after a period of therapy, but it was easily controlled by specific medication (kaolin, pectin, &c.). In a single case the treatment was interrupted because of this symptom.(ABSTRACT TRUNCATED AT 250 WORDS)

Studies on immunological paralysis. X. Cellular characteristics of the induction and loss of tolerance to levan (Polyfructose)

The induction and loss of tolerance to native and depolymerized fractions of levan, a thymus-independent antigen, have been studied in (DBA/1×CBA-T6T6)F₁ mice by a direct plaque-forming cell (PFC) assay. Tolerance following 1 mg native levan began to break by 80 days, whereas mice remained specifically unresponsive 150 days after 10 mg. Effects attributable to long persistence of antigen have been demonstrated. The following main features of levan tolerance were established by transfer of spleen cells to 900 R-irradiated recipients: (1) the induction period is very short—less than 24 hours. (2) No detectable immunity accompanies or precedes induction. (3) The fall in immunogenicity with reduction in molecular weight (mol. wt) of levan is not accompanied by loss of tolerogenicity. An effectively tolerogenic, non-immunogenic fraction (mol. wt<10,000) was found. (4) There is no rapid loss of tolerance following cell transfer (reactivity is only regained after 50 days), arguing against the existence of tolerant cells in this model.

As these results and those from corresponding investigations with SIII and HGG all show major dissimilarities, it is considered imprudent to base generalizations concerning the nature of B cell tolerance on studies with only one type of antigen. Whether or not two different kinds of specific unresponsiveness might be implicated with these cells is discussed.

Somatization, psychiatric disorder, and stress in utilization of ambulatory medical services

Examined the prediction from Mechanic's (1972) attribution theory of somatization that somatizers who are under stress will overuse ambulatory medical services. Two hundred fourteen volunteer patients from university ambulatory care clinics completed the Diagnostic Interview Schedule and the Life Experiences Inventory. We examined somatization, psychiatric diagnoses, and life stress-and the interaction of these factors-in predicting frequency of medical visits during the preceding year, after controlling for need (active medical problems) and predisposing factors. As hypothesized, life stress interacted with somatization in predicting number of medical visits; somatizers who were under stress made more visits to the clinics than did nonsomatizers or somatizers who were not under stress. Although stress affected somatizers most, stress was predictive of increased medical utilization for all patients. These results suggest that psychological services intended to reduce overutilization of outpatient medical services might best focus on stress reduction and be most beneficial to somatizers.