Age-related changes in evoked otoacoustic emissions

Outer hair cells of the organ of Corti play an important part in the genesis of evoked otoacoustic emissions (EOAEs), which are related to cochlear biomechanics. The aim of this study was to investigate the age factor in relation to EOAEs in 166 ears of subjects between 6 weeks and 83 years of age. The results show that when age increases, the presence of EOAEs by age group and the frequency peak in spectral analysis decrease, and EOAE threshold increases. Thus, there is an effect of age upon EOAEs, and it seems linked with alteration of cochlear biomechanics and/or hair cell loss. Such an effect has to be taken into consideration when EOAEs are used in clinical applications, and limits the use of EOAEs in older subjects.

High-performance liquid chromatographic determination of 4-amino-5-chloro-N-[(1-ethylimidazolin-2-yl)methyl]-2-methoxybenzamide and its metabolite in biological fluids. Applications in pharmacokinetic studies

A high-performance liquid chromatographic method with spectrofluorometric detection has been developed for the analysis of a new substituted benzamide and its metabolite in body fluids. The detection was performed at 270 nm for excitation, and 370 nm for emission. The proposed technique is selective, reliable, and sensitive. The detection limit is 1 ng/mL for the parent drug and 2 ng/mL for the imidazole derivative. The reproducibility of the analytical method through statistical coefficients is approximately 5%. The accuracy of the method is good; that is, the relative error is less than 2%. To validate this method, the stability of these two drugs was tested at the time of conservation of urine and plasma samples and during all steps of the analytical method.

Effect of contralateral auditory stimuli on active cochlear micro-mechanical properties in human subjects

The present study investigates the possibility that contralateral auditory stimulation along medial efferent system pathways may alter active cochlear micromechanics and hence affect evoked oto-acoustic emissions in humans. A first experiment, involving 21 healthy subjects showed reduction of oto-acoustic emission amplitude under low intensity contralateral white noise (from 30 dB SPL, 10 dB SL, upwards). The effect is found for intensities below the acoustic reflex threshold (85.2 dB HL). A second experiment, involving 10 of the above 21 subjects, sought to rule out any technical artefact. Recording was again carried out, but after sealing of the contralateral ear with a silicon putty plug. No contralateral intensity effect on oto-acoustic emission amplitude was found for contralateral intensities below 65 dB SPL. In subjective perception terms (dB SL) an effect was found under sealing when the sound reached or passed above the 10 dB SL level. These two findings confirm the preceding experiment. The third experiment investigated the role of transcranial transmission of the contralateral auditory stimulus. 16 subjects having total unilateral deafness and one healthy ear were tested by the same procedure as above. No fall-off in oto-acoustic emission amplitude was found for contralateral stimuli equal to or less than 80 dB SPL. There is thus a contralateral auditory stimulus effect on active cochlear micromechanics. The most appropriate explanation involves the medial cochlear efferent system, excited at brainstem level via the afferent auditory pathways. Alteration of active cochlear micromechanics seems promising at a basic level, pointing, as it does, to an interactive cochlear functioning which can be investigated by simple, non-intrusive, objective techniques which can be used with human subjects. We have here a model for functional exploration of the medial olivocochlear efferent system.

Evoked otoacoustic emissions and sensorineural hearing loss

Following Kemp's original studies, several others have confirmed the existence of otoacoustic emissions. Their clinical relevance remains, however, to be clarified. The various published studies have concerned small series. This study sought to specify otoacoustic emission characteristics in relation to sensorineural hearing loss (148 ears of 76 subjects). The results show that the presence of otoacoustic emissions drops as a function of hearing loss and that there is a highly statistically significant correlation between otoacoustic emission threshold and hearing loss at the 1000-Hz frequency. Otoacoustic emissions are never found when hearing loss at 1000 Hz exceeds 40 dB hearing level and when the mean audiometric hearing loss (at 500, 1000, 2000, and 4000 Hz) exceeds 45 dB hearing level. The main practical conclusion is that otoacoustic emission presence indicates middle frequency functional integrity of the outer hair cells of Corti's organ. Absence of otoacoustic emissions is harder to interpret.

Interface-mediated inactivation of pancreatic lipase by a water-reactive compound: 2-sulfobenzoic cyclic anhydride

2-Sulfobenzoic cyclic anhydride (SBA) rapidly and selectively inactivates porcine pancreatic lipase (PPL) only when added during the hydrolysis of an emulsified ester such as tributyrin or dodecyl acetate. The present data suggest that the inactivation of PPL occurs preferentially at the oil/water interface and not in the aqueous phase, since colipase and bile salt were found to adversely affect the inhibition process. Moreover, it is shown that at a molar ratio of SBA to pure PPL of 1, 40% of the lipase activity was already irreversibly lost. Complete inactivation was observed at SBA to pure PPL molar ratios of 120. A 60% inactivation occurred when 0.5 mol of 3H-labeled SBA was attached per mole of PPL. The SBA-inactivated PPL competes for binding to the dodecyl acetate/water interface as efficiently as the native enzyme. Larger SBA concentrations are required when crude lipase preparations are used as well as with pure PPL in the presence of bile salts and colipase. Lipases were found to have variable sensitivities to SBA inactivation, depending on their origin. In the presence of bile salts and tributyrin at pH 6.0, human gastric lipase activity was not affected by the presence of a 10(6) molar excess of SBA.

Pharmacokinetics and metabolism of the anti-arrhythmic carocainide in man

The pharmacokinetics and metabolism of the anti-arrhythmic drug carocainide have been investigated in six healthy adult volunteers following single 100 mg intravenous and oral doses. Carocainide was labelled with 14C in the benzofuran ring. After i.v. administration, plasma concentration/time decay of carocainide was triexponential. Mean plasma elimination half-life of the drug was 5.0 +/- 2.2 h (i.v.) and 5.4 +/- 1.1 h (p.o.). Carocainide was virtually completely absorbed after the oral dose. The drug was eliminated mostly as unchanged drug in urine by the two routes of administration. There was some evidence that carocainide underwent enterohepatic cycling. Binding of carocainide to plasma proteins was saturable although not in the concentration range found in vivo. The drug was bound almost entirely to the alpha 1-acid glycoprotein fraction, to one class of binding sites with a moderate affinity constant (5.5 X 10(-4) M-1). Metabolism of carocainide, a secondary elimination process, occurred by oxidative cleavage of the benzofuran ring and by N-oxidation of the pyrrolidine ring.

A single VH-gene associated with a variety of D- and J-segments encodes for a large family of ABPC48-related antibodies induced by antiidiotypic immunization

Two series of monoclonal antibodies have been obtained from BALB/c mice immunized against two antiABPC48 antiidiotypic antibodies. They are divided into two serologically different classes. Class I antibodies bind only the immunizing antibody; class II antibodies display a broad binding capacity to various antiidiotypic antibodies, and some bind levan, as does ABPC48. Northern blot analyses and partial mRNA sequencing show that all class II antibodies express the VH-gene coding for ABPC48 and UPC10 antilevan antibodies associated with a variety of D- and J-segments. The third hypervariable region of the sequenced antibody with antilevan activity is structurally related to that of ABPC48 and UPC10 antibodies but has a different genetic origin. This study indicates that the identification of idiotype-related antibodies arising from antiidiotypic immunization may be misleading, if based on their antigen-binding properties; and it stresses the importance of structural approaches for the analysis of regulatory mechanisms ruling immune responses.

V kappa gene family in (Glu60 Ala30 Tyr10)n (GAT)-specific antibodies that express CGAT (or pGAT) public idiotypic specificities. Protein and mRNA sequencing of eight monoclonal V kappa chains

A large proportion of (Glu60 Ala30 Tyr10)n (GAT)-specific antibodies expresses public idiotypic specificities, termed CGAT (or pGAT), that require the presence of both the heavy and the light chains in order to be expressed. We report in this paper the complete sequence of eight V kappa regions pertaining to eight anti-GAT monoclonal antibodies derived from three strains of mice: BALB/c, DBA/2, and C57BL/6. The methodology used a combination of NH2-terminal amino acid and mRNA nucleotide sequencing. All eight sequences analyzed, although highly homologous and all pertaining to the same V kappa 1 subgroup, allowed definition of three germline genes that are likely to be present in all three strains of mice and also in NZB. It seems likely, however, that any given strain may not necessarily use all three genes for making anti-GAT antibodies. The search for structural correlates of idiotypes could not be framed in a simple picture, but our data suggest that similar idiotopes may result from different interacting primary structures, leading to structural homologies that should be visualized at three-dimensional level.

[Study of the spermatic bacterial flora in infertile males (author's transl)]

Two groups of infertile males (65 and 132 patients) have been investigated in two different laboratories, with two different methods to obtain semen. The bacteriological results are quite similar in the two groups. The microorganisms which have been isolated are : beta-hemolytic Streptococcus, Proteus, Epidermidis staphylococcus, Micrococcus, Corynebacter, Viridans streptococcus, Klebsiella, Pseudomonas, Enterobacter, Bacillus, Neisseria, Escherichia coli, anaerobic Staphylococcus, anaerobic Streptococcus, anaerobic Corynebacter type IV. Fungus, Achromobacter, 20 p. cent of the patients are chronically infected without any clinical signs. This infection is probably of prostatic origin with an important number of bacteria in the semen (more than 3 000/ml). No relation has been shown between the bacteriological data and the physical and cytological characteristics of the sperm, except the pH : semens with a low pH are generally azoospermic and highly contaminated.

[Study of the spermatic bacterial flora in infertile males (author's transl)]

Two groups of infertile males (65 and 132 patients) have been investigated in two different laboratories, with two different methods to obtain semen. The bacteriological results are quite similar in the two groups. The microorganisms which have been isolated are : beta-hemolytic Streptococcus, Proteus, Epidermidis staphylococcus, Micrococcus, Corynebacter, Viridans streptococcus, Klebsiella, Pseudomonas, Enterobacter, Bacillus, Neisseria, Escherichia coli, anaerobic Staphylococcus, anaerobic Streptococcus, anaerobic Corynebacter type IV, Fungus, Achromobacter. 20 p. cent of the patients are chronically infected without any clinical signs. This infection is probably of prostatic origin with an important number of bacteria in the semen (more than 3,000/ml). No relation has been shown between the bacteriological data and the physical and cytological characteristics of the sperm, except the pH : semens with a low pH are generally azoospermic and highly contaminated.

Partial structure of a rat IgD molecule with a deletion in the heavy chain

The isolation, purification and characterization of the rat IR-731 monoclonal immunoglobulin is reported. The molecule is IgD-like, as appreciated from immunochemical and biochemical characteristics. H and L chains, Fab and Fc tryptic fragments have been isolated, analyzed, and partial sequence data have been obtained, including most cysteyl-containing peptides. The heavy chain contains a deletion which encompasses most of the CH2 domain and the beginning of the CH2 domain, and observation which does not reflect the intron-exon organization depicted for some murine heavy chains at the gene level. Basic structural features of the hinge region of the IgD molecule (extreme susceptibility to proteolytic enzymes, presence of basic amino acids near its COOH-terminus) have been found for the IR-731 molecule. In addition, partial sequence of the light chains points to the existence of K subgroups in the rat. Very limited amino acid changes have been identified in the K constant region, suggesting a possible--but limited--polymorphism which might be isotypic and/or allotypic in nature.

[Pneumococcal capsular types of clinical specimens. Lyon: 1972-1977 and 1978 (author's transl)]

878 strains of Streptococcus pneumoniae were tested during two periods : 667 strains from 1972 to 1977 and 211 strains during 1978. Strains were isolated from spinal fluids, blood, peritoneal fluids, urines, exudate from respiratory tract except sputum. In polymicrobial specimens, only the predominant species were serotyped. From 1972 to 1977, 53,3% of strains are typed and 6 serotypes and pools are prevalent among 68,5% of typed strains, the most frequent are : 6 - D - 18 - 19. During the second period (1978) 82,5% of strains are typed, 9 serotypes are prevalent among 68,5% of typed strains, the most frequent are : 6 - 19 - 23 - 3. During 1978, 27,6% of strains are isolated from child wards, others from adults wards. A comparison of the relative frequencies of the serotypes in the two wards shows that the following 10 serotypes are the most frequent: 6 - 19 - 23 - 3 - 18 - 1 - 8 - 9 - 14 - 4.

The surgical treatment of fractures of the upper end of the humerus by blind pinning (author's transl)

During a period of five years, the authors have treated 250 fractures of the upper end of the humerus. Fifty-one were treated by blind pinning. Six to eight Kirschner wires are passed up to the head of the humerus under X-ray control through a hole made on the posterior aspect of the lower end of the humerus just above the olecranon fossa. The functional results were satisfactory in 70% of cases. The indications for pinning were for severely displaced fractures, comminuted fractures, either impacted or not, or slipping of the upper humeral epiphysis. The results were less satisfactory in cases with an elevated greater tuberosity. The technique cannot be applied to fracture-dislocations.

Structural and functional mapping of immunoglobulin V-regions

V-regions of immunoglobulins chains contain 3 types of positions, which are equally represented: invariant and sub-group characteristic, which account for the "framework" and hypervariable positions, responsible for antigen recognition. The 3 types of positions are grouped and fall within a very few discrete stretches. Sub-group characteristic segments containing one of the 2 cysteyl residues of the V-regions may be isolated by high voltage paper electrophoresis and provide a basis to type for sub-groups in the VK and in the VH human systems. This allowed to characterize a large set of human myeloma proteins that were used in a series of competitive hybridizations which indicated that sub-groups had no influence on preferential reassociations, which occurred in 80% of the cases. This preference seems to rely mostly on individual structural differences, which may be linked to heterogeneity at the framework level. Distinction between framework heterogeneity and hypervariable regions heterogeneity may be approached by raising antibodies against a mouse myeloma protein, MOPC 173, of known sequence, by means of syngeneic and allogeneic immunizations, using Balb/c and A/J mice. Junction of distinct portions of immunoglobulin chains such as the V and the C regions raises the possibility that some recognition signals may operate at the DNA level. Since rotational symmetry regions in the DNA are known to act as such signals, it is discussed whether such regions can be expected from the amino acid sequence data, especially in the vicinity of the "switch" peptide.