Interrelations between transiently evoked otoacoustic emissions, spontaneous otoacoustic emissions and acoustic distortion products in normally hearing subjects

Active cochlear mechanisms and especially outer hair cells seem to be involved in oto-acoustic emissions (OAEs) genesis. This study sought to investigate basic characteristics of spontaneous otoacoustic emissions (SOAEs), click-evoked otoacoustic emissions (TOAEs) and interrelations between SOAEs, TOAEs and 2f1-f2 and 2f2-f1 distortion product OAEs (DPOAEs) in 135 normally hearing subjects. A gender effect was shown on TOAEs and DPOAEs amplitude, and is attributed to the higher incidence of SOAEs in women (58%) than in men (22%). Moreover, SOAEs presence seems to mask the age effect found, especially at high frequency components, on TOAEs amplitude. A general influence of SOAEs on TOAEs and DPOAEs is shown, especially at frequencies ranging from 1 kHz to 3 kHz, collecting more than 66% of the SOAEs peaks recorded. Lastly, correlations between TOAEs frequency band amplitude and 2f1-f2 DPOAEs amplitude, shows frequency specificity, at least at low frequencies (i.e., from 0.5 to 2 kHz) in agreement with previous works suggesting that the 2f1-f2 DPOAEs generation site is at the geometric mean of the primaries. The same correlations calculated with 2f2-f1 DPOAEs amplitude show frequency specificity at low frequencies i.e., at 800 Hz and 1600 Hz. 2f2-f1 DPOAEs in humans are shown to be generated near the 2f2-f1 frequency region on the cochlear partition.     

Glucose metabolism,enzymic analysis and product formation in chemostat culture of Hanseniaspora uvarum

The physiology of Hanseniaspora uvarum K₅ was studied in glucose-limited chemostat cultures and upon glucose pulse. Up to a dilution rate of 0·28 h^?1, glucose was completely metabolized in biomass and CO₂. Above this value, increase in the dilution rate was accompanied by sequential production of metabolites (glycerol, acetate and ethanol) and decrease in cell yield. Similar results were observed upon glucose pulse. From the enzyme activities (pyruvate dehydrogenase, pyruvate decarboxylase, NAD and NADP-dependent acetaldehyde dehydrogenases, acetyl coenzyme A synthetase and alcohol dehydrogenase) and substrate affinities, the following conclusions were drawn with respect to product formation of cells: (1) pyruvate was preferentially metabolized via pyruvate dehydrogenase, when biomass and CO₂ were the only products formed; (2) acetaldehyde formed by pyruvate decarboxylase was preferentially oxidized in acetate by NADP-dependent aldehyde dehydrogenase; acetate accumulation results from insufficient activity of acetyl-CoA synthetase required for the complete oxidation of acetate; (3) acetaldehyde was oxidized in ethanol by alcohol dehydrogenase, in addition to acetate production.     

Measurement of the vascular mass of the human radial artery by ultrasonics

OBJECTIVE: To determine the reproducibility of radial artery mass (RAM), in hypertensive patients. DESIGN AND METHODS: In 49 patients, RAM was measured using a high resolution echotracking device (Nius-02) which allows noninvasive measurement of diameter and wall thickness of the radial artery. RAM was validated in vitro by comparing weight of arterial segments to ultrasonographic measurement and determined as RAM = r (pi Re2-pi Ri2) where r is the arterial wall density (1.06 g/cm3), and Re and Ri are values of internal and external radii, respectively. Repeatability coefficient (RC2 = SDi2/n) was 1.3 mg. RESULTS: Blood pressure was (mean +/- SD) 146 +/- 19/85 +/- 15 mmHg, radial arterial diameter was 2,449 +/- 376 microns, radial wall thickness was 302 +/- 68 microns, RAM was 28 +/- 9 mg (range 13-43 mg). CONCLUSION: These results indicate that radial artery mass can be measured using a high resolution echotracking device.     

Overview of a quality assurance/quality control compliance program consistent with FDA regulations and policies for somatic cell and gene therapies: a four year experience

Somatic cell and gene therapy involve the application of biological technologies to an individual patient through the use of living cells which provide a therapeutic benefit (Aliski, 1991). Various forms of cellular and gene therapies are being developed and evaluated in an increasing number of clinical trials for congenital and acquired disorders. The potential and progress of these therapeutic applications have resulted in an increasing effort by the Food and Drug Administration (FDA) to develop the regulatory framework under which these therapeutic approaches would insure safety and efficacy, the primary mandate of the FDA. Over five years ago Cellcor began to define the parameters, specifications, and conditions relevant to a Quality Assurance/Quality Control (QA/QC) program that has evolved to insure safety and maximize the efficacy of applications of the company's ex vivo technology, autolymphocyte therapy. Autolymphocyte therapy is an outpatient form of somatic cell immunotherapy based upon the infusion of T cells that have been activated ex vivo using a combination of previously generated autologous cytokines and an anti-CD3 monoclonal antibody. We have been able to demonstrate the feasibility for the safe, controlled, and consistent preparation and delivery of a cellular therapy by application of relevant GMP regulations. This presentation reviews aspects of this program and chronicles our experience which at present amounts to over 4400 in fusions for over 700 patients. This program provides a high degree of assurance that a cellular therapy program can be carried out in a multisite mode involving hundreds of patients through the strict adherence to cGMP as set forth in existing regulations.(ABSTRACT TRUNCATED AT 250 WORDS)     

Influence of impurities,such as carbon and sulphur,on the high temperature oxidation behaviour of Fe72Cr23Al5 alloys

Kinetic and analytical study of oxidation behaviour of Fe₇₂Cr₂₃Al₅ alloy in relation to the microstructure, particularly carbon and sulphur localization and chemical state, indicates that these elements have a strong influence on alumina growth and adherence. Competition between oxidation and a carbide precipitation slightly increases the oxidation rate during isothermal treatments but has a beneficial influence on the oxide scale adherence. Sulphide precipitation in the metallic substrate has a disastrous effect on oxidation: large weight gains are observed, due to internal oxidation at sulphides and presence of sulphur in the alumina. Moreover, it was confirmed that alumina growth is controlled by preferential oxygen diffusion along short-circuit paths.     

Evolution of well-defined surface contour submitted to ion bombardment: computer simulation and experimental investigation

The previously published theory of our model on the evolution of a surface contour under ion etching is recalled. Further improvements dealing with angular points of the profile shows that: angular points having straight trajectory may exist; and they can be found either by computation or by graphic method. The experimental verification of the model is made on steps etched in silicon. SEM observations of the evolution of such steps under argon ion bombardment show good agreement between computed and experimental results.     

Etude experimentale de la penetration du soufre dans les alliages Ni-Cr-Fe (77/16/7) de type inconel 600: II. Diffusion du soufre sous forme atomique

The coefficients of thermal expansion (CTE) of eleven isotropic and anisotropic nuclear graphites made of either gilsonite coke or needle coke were measured from room temperature to 900°C by using a dilatometer, and they were compared with the BAF (Bacon anisotropy factor) measured at room temperature and the CTE's of crystallites.The CTE for each sample increased and its anisotropic ratio decreased with increasing temperature, and the latter showed the same value of BAF at elevated temperatures. A difference between the CTE of a bulk sample and that of crystallites, and also the change in an accommodation factor, were observed at elevated temperatures.     

A clinical evaluation of transdermal therapeutic system fentanyl for the treatment of cancer pain

PROBLEM: Circulating inflammatory cytokines have been implicated in the pathogenesis of preeclampsia. To test this hypothesis, we measured plasma levels of immunoreactive tumor necrosis factor (TNF)-alpha and -beta, interleukin (IL)-1 alpha and -beta, and IL-6 and -10 in women with preeclampsia, in women with transient gestational hypertension, and throughout normal pregnancy. METHOD OF STUDY: Enzyme-linked immunosorbent assays were used and subjected to extensive validation studies. RESULTS: The median concentration of plasma TNF-alpha was increased by twofold in women with preeclampsia compared with that in normal third-trimester pregnancy (P < 0.001) and in women with gestational hypertension (P < 0.04). The median concentration of plasma IL-6 was increased by threefold in women with preeclampsia compared with that in normal third-trimester pregnancy (P < 0.001) and increased twofold compared with that in women with gestational hypertension (P < 0.1). There were no significant differences observed in the levels of plasma IL-1 beta and IL-10 between the preeclamptic and other subject groups. The level of IL-1 beta, but not the levels of IL-10, TNF-alpha, or IL-6, was significantly changed during normal pregnancy compared with the nonpregnant condition manifesting an overall decline (P < 0.04). TNF-beta and IL-1 alpha were not detected in any samples, possibly because of the low sensitivity of these particular immunoassays. CONCLUSION: Elevated levels of TNF-alpha and IL-6 may contribute to the putative endothelial dysfunction of preeclampsia.     

Lung cancer mortality in a French cohort of hard-metal workers

A cohort mortality study was carried out among workers of a plant producing hard metals using cobalt as a binder. This study was aimed at assessing possible lung cancer risks in relation with cobalt exposure. Seven hundred nine male workers with at least 1 year of employment were included in the cohort and followed for mortality from 1956 to 1989. Job histories were provided by the administration of the plant, whereas smoking habits were collected from medical records and by interview. The causes of deaths were ascertained from hospital and general practitioner records. The observed numbers of deaths (obs) were compared with the expected based on national rates with adjustment for age, sex, and calendar time (standardized mortality ratio; SMR). The overall mortality did not differ from that expected (obs = 75, SMR = 1.05), whereas mortality due to lung cancer was in significant excess (obs = 10, SMR = 2.13). This excess was higher among workers employed in the areas with the highest exposure (obs = 6, SMR = 5.03). No trend was observed, however, with duration of employment or time since first employment. Smoking data were available for 81% of the workers and 69% of the deceased and showed that smoking alone does not account for these lung cancer excesses, yet, because of the small numbers involved, no firm conclusion should be drawn from this study.     

Physiological approach to heterologous human serum albumin production by Kluyveromyces lactis in chemostat culture

Production of recombinant human serum albumin (rHSA) controlled by the constitutive promoter phosphoglycerate kinase was studied in Kluyveromyces lactis. It was governed by both cell concentration and glycolytic flow. The triggering of the fermentation metabolism by unfavourable culture conditions (pH, pO₂, D) caused a decrease in the synthesis of the heterologous protein. The highest productivity (75 mg 1^?1 per h) and rHSA concentration (62 mg 1^?1) were obtained in chemostat culture with a dilution rate of 0·12 h^?1 and with 38 g 1^?1 dry weight.