A comparison of three finite element models of an edentulous mandible provided with implants.

The stress distribution in an edentulous mandible provided with two implants in the interforaminal region was calculated by means of three different finite element models. The implants were connected with a bar or remained solitary. The first model was a three-dimensional representation of the entire mandible, the second model of the interforaminal region of this same mandible, whilst the third model was a two-dimensional representation of the interforaminal region.

Can seduction make straight men gay?

The article raises the question of changing sexual preference: Can a man whose past sexual practice has been almost exclusively heterosexual change his practice to homosexual after being seduced by another man? To those who believe that homosexual preference is homosexual orientation, an innate biological predisposition, the answer is a resounding "no." Contrary to this response, the author presents three cases in which the men switch from heterosexual to homosexual relationships (exclusively in two cases) by means of a sexual encounter initiated by another man. The author credits part of the change to the gay liberation movement which rescued homosexual desire from the hidden, forbidden, and shameful.

Standardized radiographs of the alveolar crest around implants in the mandible.

The techniques currently used for standardized longitudinal radiographic evaluation of the supporting bone around dental implants are not suitable for general application. An aiming device is described for intraoral radiography used to evaluate the crestal bone height around dental implants used as retention for overdentures. This aiming device has been tested on four different implant systems by four dentists.

Stress distribution around dental implants: influence of superstructure, length of implants, and height of mandible.

The stress distribution around dental implants was investigated by use of a two-dimensional model of the mandible with two implants. A vertical load of 100 N was imposed on abutments or the bar connection. The stress was calculated for a number of superstructures under different loading conditions with the help of the finite element method.

Bracteomania, an inflorescence anomaly, is caused by the loss of function of the MADS-box gene squamosa in Antirrhinum majus.

Anomalous flowering of the Antirrhinum majus mutant squamosa (squa) is characterized by excessive formation of bracts and the production of relatively few and often malformed or incomplete flowers. To study the function of squamosa in the commitment of an inflorescence lateral meristem to floral development, the gene was cloned and its genomic structure, a well as that of four mutant alleles, was determined. SQUA is a member of a family of transcription factors which contain the MADS-box, a conserved DNA binding domain.

Recovery and identification of DNA sequences harboured in preserved ancient human bones.

A new method is presented to extract and identify specific DNA fragments from well preserved human bones, dating from three different time periods. Bone samples were thoroughly freed from surfacial contaminating DNA. Access to the inner bone spongiosum was achieved by removing the covering bone layers of the vertebra or sternum, whereas the patella, tibia and caput of the femur or humerus were cleaved with an iron saw.

Cavernous hemangioma of the internal acoustic canal.

A case report of a 39-year-old man suffering from left-sided, progressive hearing loss is presented. As well, the patient noted ipsilateral recurrent facial paralysis. MRI succeeded in confirming the presence of a tumor in the internal acoustic canal 18 months after the first MRI.

Suddenly symptomatic brain tumors at altitude.

High-altitude cerebral edema can present with a wide variety of neurologic manifestations; these symptoms resolve with descent. The persistence of neurologic symptoms after descent suggests an intracranial lesion. Brain tumors suddenly becoming symptomatic at altitude have not been reported previously.

[Phenylketonuria as a model system for DNA diagnosis of hereditary disorders].

Phenylketonuria (PKU), due to a defect in phenylalanine hydroxylase (PAH), is presented as a model system for computer-aided DNA diagnosis of genetic diseases. Eight different restriction fragment length polymorphism (RFLP) markers have been localized within the introns of the 90 kb PAH gene (located on chromosome 12). These RFLPs can be combined in 384 different ways and each combination has been defined as a particular haplotype.

Effect of organic substrates on biological sulphide oxidation.

Neither acetate nor higher fatty acids and glucose have a significant effect on the biotechnological process for sulphide removal at 20 degrees C, in which sulphide is oxidized to sulphur using oxygen. The oxidation of acetate and propionate with oxygen is mainly dependent on the sulphide and oxygen concentrations in the reactor. The occurrence of Thiothrix filaments in sulphide-removing waste-water treatment systems has been investigated using a fixer-film upflow reactor.

A new porous polyetherurethane wound covering.

A polyetherurethane (PEU) wound covering with non-interconnected micropores up to approximately 5 microns has been prepared by means of a phase inversion process. This highly elastic, very thin (15-20 microns), pliable wound covering showed good, immediate adherence to wet wound surfaces and high water vapor permeability, but was impermeable to bacteria. In guinea pigs epidermal wound healing of partial-thickness wounds under PEU wound coverings was accelerated compared with uncovered controls and an occlusive wound covering, OpSite.

Distribution of meiotic recombination along nondisjunction chromosomes 21 in Down syndrome determined using cytogenetics and RFLP haplotyping.

Ten families (Down syndrome children and their parents) showing evidence of meiotic recombination between intraparental chromosomes transmitted after nondisjunction were studied. Cytogenetic polymorphisms and a cassette of RFLP markers distributed along chromosome 21 were used to analyze these families to localize the regions of meiotic recombination. Results indicated that only one crossover occurred per meiotic division and that nine of ten nondisjunctions appeared to be of maternal origin.

Effect of selective chemical modification and CNBr-cleavage at methionine20 in catalytic activity and substrate binding properties of porcine pancreatic phospholipase A2.

Porcine pancreatic phospholipase A2 contains 2 methionine (Met) residues located at positions 8 and 20, respectively. Reaction of the enzyme with methyliodide and iodoacetic acid resulted in the selective methylation and carboxymethylation, respectively, of Met20. It was found that porcine pancreatic iso-phospholipase A2, possessing only Met8, was not affected by either modification.

On the origin of recurrent trisomy 21: determination using chromosomal and DNA polymorphisms.

A family is described in which two cases of trisomy 21 occurred in, respectively, a newborn infant and a prenatally diagnosed fetus. Using fluorescent chromosomal polymorphisms, it was established that in both cases the extra chromosome resulted from a first meiotic division error in the mother and that the father contributed the same centromeric region to both children. RFLP-associated probes were used to examine the genetic content of the chromosomes.

The development and characterization of monoclonal antibodies against rat cytomegalovirus induced antigens.

In this paper the development of a battery of approximately 70 mouse monoclonal antibodies (McAbs) to RCMV-induced antigens and their characterization is discussed. Their reactivity with the whole scala of ca. 30 virus specific proteins was tested in an enzyme linked immunoassay (ELISA) whereas their ability to detect RCMV-antigens at different locations of in vitro infected cell cultures and at different stages of infection was tested by immunofluorescence.

Molecular cloning and restriction endonuclease mapping of the rat cytomegalovirus genome.

Rat cytomegalovirus (RCMV) DNA was cleaved by restriction endonuclease EcoRI into 24 fragments ranging in mol. wt. from 34 X 10(6) to 0.

Studies on rat cytomegalovirus induced structural and non-structural proteins present at (immediate-)early and late times of infection.

Radioactive-labelled virions and nucleocapsids of rat cytomegalovirus (RCMV) were purified from the supernatant and subcellular fractions of infected rat embryo fibroblasts (REF) and analyzed by SDS-polyacrylamide gel electrophoresis. Nuclear nucleocapsids contain one major protein of 138 kD, which is considered to be the basic invariant structural element of RCMV. Enveloped virions consist of 28 protein species, five of which were clearly identified as glycoproteins (58, 64, 76, 112 and 118 kD).

Road traffic noise annoyance in Amsterdam.

3445 persons living in Amsterdam (1507 male and 1938 female), aged 41-43 years, participated in an investigation in which the relationship was studied between the (measured) road traffic noise in front of the houses in which the participants lived, and the (reported) resulting annoyance and sleep disturbance. We found a smaller number of persons with annoyance and sleep disturbance than we had expected as a result of other investigations. Considerable differences in the annoyance experience were found for different categories of noise-sensitivity.

Biology of rat cytomegalovirus infection.

Cytomegalovirus infection of Brown Norway rats was studied after intraperitoneal or subcutaneous inoculation of virus. No clinical illness was apparent during the 1st month postinfection (p.i.

Rat cytomegalovirus induces cellular purine and pyrimidine nucleoside kinases in rat embryo fibroblasts and TK- rat-2 cells. Correlations with the antiviral activity of Acyclovir.

Rat cytomegalovirus (RCMV) induces a cytosol thymidine kinase (TK) in G0-phase rat embryo fibroblasts (REF), but not in a TK deficient rat cell line (R-2), though virus titers in both cell types reached comparable levels. The results indicate that TK is neither virus-coded nor is required for a productive infection in R-2 cells. A deoxycytidine kinase (dCK) is induced in either growing or RCMV-infected REF and R-2 cells, suggesting that dCK is essential for both host-cell and viral DNA synthesis.

Rat cytomegalovirus: studies on the viral genome and the proteins of virions and nucleocapsids.

The nucleocapsids (N-capsids) isolated from the nuclei of rat cytomegalovirus (RCMV)-infected rat embryo fibroblasts (REF) are composed of three major proteins: 142 X 10(3) (142K), 40K and 32K mol. wt. Nucleocapsids isolated from the cytoplasmic fraction (C-capsids) are composed of proteins found in N-capsids and five major and seven minor new protein species.

Isolation of a cytomegalovirus-like agent from wild rats.

In 8 of 10 wild rats trapped in The Netherlands, an infectious viruslike agent was isolated predominantly from the salivary glands and could be serially passed in laboratory rats. In rat embryo cells a typical cytomegalo-like cytopathic effect was produced. The morphologic and cultural characteristics of the isolated agent were comparable with those of the mouse cytomegalovirus (MCMV).