Ultrahistochemical demonstration of cations in the guinea pig organ of Corti.

The distribution of cations in the guinea pig organ of CORTI was studied by means of the ultrahistochemical pyroantimonate method. In the outer hair cells precipitates were localized at the cell membrane, at stereocilia, in the subplasmalemmal cisterns, in the the nucleus, in mitochondria and within the ground plasm. Coarse precipitates at the cell membrane may consist mainly of cations other than calcium ions. The subplasmalemmal cisterns are suggested to sequester cations in the outer hair cells. The mechanism of the trapping reaction and factors injuring this histochemical method are discussed.     

Evaluation of corrosion on plasma sprayed and anodized titanium implants,both with and without bone cement

The corrosion behavior of titanium with vacuum plasma sprayed titanium coatings and with anodized surfaces, both with and without polymeric bone cement were evaluated. Electrochemical extraction tests were carried out with subsequent analysis of the electrolyte by ICP-MS in order to verify our hypothesis of the ionic permeability of the polymer cement. The complexity of the situation resides in the existence of two interfaces: electrolyte-polymer and polymer-metal. The surface preparation (treatment of the surface) plays an important role in the corrosion resistance of titanium. The electrochemical magnitudes that were examined reveal that the plasma spray surfaces have the lowest corrosion resistance. The cement, in spite of having reduced electrical conductivity in comparison to metal, is an ionic transporter, and therefore capable of participating in the corrosion process. In the present study, we observed in fact crevice corrosion at the metal-cement interface. In the case of plasma spray surfaces, a process of diffusion of titanium particles in the electrolyte could accompany the crevice corrosion. In this study, we have shown that there is a corrosion process at the surface of the titanium through the cement which has as a consequence on the one hand the formation of titanium cations and on the other hand the growth of a passive layer on the titanium. In conclusion, we identified two principal factors that influence the corrosion process: [1] the type of surface treatment for the titanium, and [2] the ionic conductivity of the cement. There is indeed ionic transport through the cement; as evidenced by the presence of titanium in the electrolyte solution (ICP-MS analysis) and chloride at the surface of the titanium sample (EDX analysis).We show that the polymer cement is an ionic conductor and participates in the corrosion of the embedded titanium. We cannot deduce from our results, however, whether the polymer itself possesses corrosive properties. Long-term experiments will be necessary to study the degradation behavior of the polymer cement.     

Rapid neurofibrillary tangle formation after localized gene transfer of mutated tau

Neurofibrillary pathology was produced in the brains of adult rats after localized gene transfer of human tau carrying the P301L mutation, which is associated with frontotemporal dementia with parkinsonism. Within 1 month of in situ transfection of the basal forebrain region of normal rats, tau-immunoreactive and argyrophilic neuronal lesions formed. The fibrillar lesions had features of neurofibrillary tangles and tau immunoreactivity at light and electron microscopic levels. In addition to neurofibrillary tangles, other tau pathology, including pretangles and neuropil threads, was abundant and widespread. Tau gene transfer to the hippocampal region of amyloid-depositing transgenic mice produced pretangles and threads, as well as intensely tau-immunoreactive neurites in amyloid plaques. The ability to produce neurofibrillary pathology in adult rodents makes this a useful method to study tau-related neurodegeneration.     

Immunity against Helicobacter pylori: significance of interleukin-4 receptor alpha chain status and gender of infected mice

Vaccination of interleukin-4 (IL-4) receptor alpha (IL-4Ralpha) chain-deficient BALB/c mice with Helicobacter pylori urease and cholera toxin or with urease-expressing, live attenuated Salmonella enterica serovar Typhimurium cells revealed that protection against H. pylori infection is independent of IL-4- or IL-13-mediated signals. A comparison of male and female mice suggests a sexual dimorphism in the extent of bacterial colonization that is particularly evident in the absence of the IL-4Ralpha chain.     

Isolation of genital mycoplasmas and Chlamydia trachomatis in stillborn and neonatal autopsy material

Chlamydia trachomatis and the genital mycoplasmas are significantly prevalent in sexually active women. How these organisms may affect the outcome of pregnancy and the neonate was the principal thrust of this investigation. Placenta, liver, and lung tissue were cultured from Mycoplasma hominis, Ureaplasma urealyticum, Chlamydia trachomatis, and aerobic as well as anaerobic bacteria in 432 stillborn and neonatal autopsies. Genital mycoplasmas were isolated from 36 cases (8.3%). Acute chorioamnionitis and funisitis were present significantly more often in cases with genital mycoplasma than in those without these organisms. Isolation of genital mycoplasmas was not associated with an increased incidence of intrauterine fetal death, villitis, hyaline membrane disease, congenital anomalies, or polymorphonuclear leukocytes in alveolar spaces. Chlamydia trachomatis was not found in any of the sites sampled.     

Immunological properties of the human Goodpasture target antigen.

IgE rheumatoid factor activity was found to be significantly elevated (P less than 0.01) using an ELISA assay when paired synovial fluid and sera from 13 patients with active RA were compared to ten control samples. Synovial fluid IgE RF activity was higher than predicted by diffusion alone in 7/11 (64%) of the RA synovial fluids studied when coefficients of diffusion were determined. The specificity of IgE RF activity as measured by the ELISA was confirmed using immunoaffinity chromatography. Mast cells, obtained by enzymatic dispersion of rheumatoid synovial tissue, were sensitized with sera containing either IgE antibodies directed against ragweed or IgE with RF activity. Histamine was released upon challenge with anti-IgE antibodies (33.2% +/- 11), ragweed antigen E (34.6% +/- 11), or aggregated gamma globulin (47.6% +/- 17.9). No histamine release was observed if antigen challenge occurred in the absence of appropriate sensitization, with C3 anaphylatoxin, or after immunoadsorption of IgE from sera containing IgE RF activity.     

Behavioral and hormonal effects of attachment object separation in surrogate-peer-reared and mother-reared infant rhesus monkeys

Mother-reared and surrogate-peer-reared rhesus monkeys were separated from their respective attachment objects at 6 months of age and tested for the following 9 weeks to determine their home cage behavior and their pituitary-adrenocortical responses to stress. Both groups displayed a strong immediate behavioral response to separation which was characterized by increases vocalization, increased locomotion, and decreased self-play. However, the surrogate-peer-reared infants showed a subsequent recovery in their levels of self-play whereas the mother-reared infants instead developed stereotypic behavior patterns such as repetitive pacing. The 2 groups displayed similar plasma cortisol responses to weekly sessions in an apparatus equipped with animated toy “monsters.” Mother-reared but not surrogate-peer-reared subjects, however, also manifested elevated cortisol levels when an animal in an adjacent cage was captured and removed for stress testing. Mother-reared infant monkeys thus responded in a stronger and more prolonged manner to the loss of their attachment object than surrogate-peer-reared infants. These results suggest that infant rhesus monkeys form stronger attachments to monkey mothers than to inanimate surrogate mothers, a phenomenon which has not been as clearly demonstrated using other indices of attachment strength.     

Whole-blood hemagglutination inhibition test for venereal disease research laboratory (VDRL) antibodies

Nontreponemal antibody tests such as the Venereal Disease Research Laboratory (VDRL) test are carried out on serum and widely used as screening tests for syphilis. The aim of the present study was to develop a screening test for syphilis making use of whole blood and VDRL liposomes. Antibody to human red blood cells was conjugated to VDRL liposomes and reacted with a diluted sample of patient whole blood. A total of 951 samples were tested by the new test and the VDRL tube test. All 49 VDRL samples positive by the VDRL test showed inhibition of hemagglutination in the whole-blood test (sensitivity, 100%). Of 902 samples with negative results by the VDRL test, 901 caused hemagglutination when tested with the liposomes (specificity, 99.9%). The hemagglutination inhibition method tests for syphilis in a simple one-step procedure in which whole blood is added to a tube containing liposomes. The new test has potential for point-of-care testing in developing countries.     

Geriatric autopsy pathology in centenarians

The determinate causes of death, physical findings, and major pathologic findings in the organ systems of 32 patients, aged 100 years or older who died between 1921 and 1983, on whom autopsies were performed, are described. Atherosclerosis, neoplasia, and bronchopneumonia were common, but diabetes mellitus, obesity, hypertension, and cerebrovascular accident were absent or rare. Deaths from infection were fewer in the era of antibiotic usage, while cardiovascular and neoplastic deaths became more frequent during that time. The pathologic findings in our series of centenarians indicate that few of these patients died from debilitating diseases and that mortality from infection has been modified by antibiotic usage.     

Bases anatomiques des vagotomies

Résumé La réalisation des différentes vagotomies, tronculaires, sélectives, supra-sélectives, nécessite la connaissance de l'innervation parasympathique de l'estomac.La disposition modale, les variations anatomiques et les données les plus récentes des constations per-opératoires sont analysées dans cet article.