Biomedical subjects
J Becker
Publications and source records attributed to J Becker.
Maturation of the coherence of EEG activity in normal and learning-disabled children.
The age effect on coherence has been studied in control (98) and learning-disabled (LD, 54) school-aged children (from 6.0 to 16.8 years old). The EEG recordings were made at rest in 15 leads, and 105 pairwise combinations for coherence were calculated (each lead was compared with all the rest) for delta, theta, alpha, beta and total frequency bands. A significant increase of coherence with age was found in both groups, with a different pattern of maturation. In the control group, a significant increase with age was found in the coherences between posterior regions and vertex (Cz). A significant decrease with age in the coherence between frontal areas was observed, especially in the theta band. The LD group showed a different pattern: no significant relation with age was found in the coherence between any lead and vertex. A high effect of age on coherence between temporal regions was observed with a predominance of the left side in comparison with the contralateral and the ipsilateral. No decrease in frontal coherence was found: in the same region where the control group showed negative values with age, the LD groups had no age effect. The results obtained are discussed as differences in brain organization, in myelogenesis and synaptogenesis and an explanation of the etiology of LD is proposed.
Detection of the mRNA encoding vitellogenesis inhibiting hormone in neurosecretory cells of the X-organ in Homarus americanus by in situ hybridization.
Vitellogenesis inhibiting hormone (VIH)-mRNA in secretory cells of the eyestalk of Homarus americanus was detected by nonradioactive in situ hybridization (ISH) using two digoxigenin-tailed oligonucleotide probes deduced from the peptide sequence. Two distinct clusters of positive cells were observed in the medulla terminalis ganglionic X-organ (MGTX). Only one of them gave a strong immunoreaction after incubation with a specific polyclonal anti-VIH serum and corresponded to the conventionally described VIH producing cells. The significance of the cells reacting positively in ISH but not in immunocytochemistry (ICC) is discussed. Northern blot analysis using 32P-labeling confirms the specificity of the probes and indicates an approximate size of 2.5 kb for VIH mRNA.
Restoration of the lateral sinus wall using a collagen type I membrane for guided tissue regeneration.
A collagen type I membrane prepared from bovine pericard was used to restore and thicken the lateral sinus wall after resection in 6 Göttingen minipigs. One rehydrated collagen type I membrane was placed on the intact sinus mucosa. A hydroxyapatite block was placed on this membrane and covered with a second membrane. After 6 months there was complete, bony regeneration in the space between the 2 membranes and thickening of the new bone plate compared to the untreated control side. This study shows that a collagen membrane can be applied for guided tissue regeneration.
Histological distribution of polymerase chain reaction--amplified human papillomavirus 6 and 11 DNA in penile lesions.
The purpose of this study was to ascertain the histological pattern of distribution of human papillomavirus (HPV) 6 and 11 DNA in penile lesions by in situ hybridization after amplification by the polymerase chain reaction (PCR). HPV DNA was routinely detected by in situ hybridization with or without PCR amplification in granular layer cells that showed perinuclear halos and nuclear atypia. Cells that lack these histological features rarely exhibited HPV DNA with conventional in situ hybridization. However, after PCR amplification, in situ analysis showed that many of the cells that lacked halos and atypia contained HPV DNA. The hybridization signal often localized to crevices in the epithelium where there was relative hyperkeratosis and a thickened granular layer. HPV DNA was not noted in the basal cells and was rarely identified in other parts of the lesion. It is concluded that penile tissues may contain HPV DNA when lacking the diagnostic features of a condyloma/low-grade intraepithelial lesions and that such tissues usually demonstrate specific histological changes characterized by a focally thickened granular layer often associated with epithelial crevices.
Detection of occult lymph node metastases in malignant melanoma.
An accurate prediction of the prognosis of melanoma is dependent on the ability to determine the presence or absence of malignant cells in lymph nodes. Our laboratory has developed a method for screening lymph node sections for the presence of micrometastatic disease. The nodes obtained from regional lymphadenectomies are dissected free from surrounding tissue and divided into halves. One-half is subjected to routine histopathological evaluation and the other one-half is disrupted into a single cell suspension and placed into cell culture. Lymph nodes from 19 patients with malignant melanoma were evaluated by tissue culture. Tumor cells were isolated in 125 of the 173 nodes examined. In contrast, only 14 of these nodes were initially found positive for melanoma by routine pathological evaluation. All lymph nodes positive for melanoma by pathological evaluation were also culture positive. Examination by cell culture has led to an upgrade in the stage of disease in 58% of the histologically node-negative patients. In addition, 43% of the patients who were histologically node negative but culture positive have recurred, suggesting some clinical correlation. These results indicate that the tissue culture method for detecting micrometastatic lymph node disease may prove more reliable and sensitive than current techniques for determining the presence of occult melanoma.
Ectomesenchyme of ameloblastic fibroma reveals a characteristic distribution of extracellular matrix proteins.
The distribution of collagens type I, IV and VI, procollagen type III and of undulin was studied in four cases of ameloblastic fibroma (AF). The ectomesenchyme of AF revealed an as yet unobserved organization of these extracellular matrix proteins with collagen type VI clearly predominating over collagen type I, procollagen type III and undulin, that showed a weak and amorphous distribution throughout the tumor stroma. Undulin, a glycoprotein that is associated with mature collagen fibrils and with differentiated tissues, was not detectable in the tumor stroma of AF except for a slow expression around capillaries and in areas with a high cellularity. We could demonstrate that the characteristics of extracellular matrix composition allowed a clear distinction between the ectomesenchyme of AF and the adjacent normal mesenchymal stroma. Due to the specific staining patterns it was possible to detect epithelial tumor islands outside the typical ectomesenchymal stroma. Our findings furthermore indicate that epithelial cells of AF invade the adjacent normal mesenchyme possibly inducing de novo formation of ectomesenchymal tumor stroma.
Topical application of hexadecylphosphocholine in patients with cutaneous lymphomas.
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Visual evoked potentials, attention and mnemonic abilities in children.
We analyzed the correlation between attention and mnemonic processes and different visual evoked potential (VEP) parameters. A group of 34 children between 9 and 13 years old was studied. VEPs were recorded in C3, C4, P3, P4, O1, O2, T5 and T6 with linked ear lobes as reference. Two different types of stimuli were used: flash and checkerboard pattern. The power of VEPs was calculated as the sum of the square amplitude values for different time epochs. Correlation coefficients between left and right homologous VEPs were also computed. A visual selective attention task divided into 5 items of increasing difficulty and the Sternberg paradigm were applied. The performance was automatically evaluated by the computer, giving the number of correct responses (NCR) and other measures of performance. Correlation coefficients between VEP parameters and the scores obtained in the performance of tasks were calculated. It was observed that power in P3, P4, T5, and T6 and the correlation coefficients between central, parietal and temporal VEPs were positively correlated with NCR of both tasks. However, power in O1 and O2 was negatively correlated with NCR.
Rapid in situ detection of PCR-amplified HIV-1 DNA.
The low copy number of human immunodeficiency virus 1 (HIV-1) DNA infected cells precludes routine detection by in situ hybridization. The inability to detect cells latently infected by HIV-1 makes difficult the study of factors that induce viral transcription, an essential factor in the development of the acquired immune deficiency syndrome (AIDS). A sensitive and rapid technique to detect HIV-1 DNA could be used as a diagnostic test for AIDS and to differentiate latent versus active viral infection. We describe a 3-h technique whereby HIV-1 DNA is amplified by hot start polymerase chain reaction (PCR) and detected directly in infected cells. The specificity of the assay was demonstrated by double labeling the positive cells with CD4. Using a CR10 HIV-1-infected cell line, the 90% of cells that were HIV-1 DNA positive could be distinguished from the 10% that were actively expressing HIV-1 RNA. The PCR in situ technique should allow for the direct localization of DNA sequences in cells that would otherwise be undetectable by conventional in situ analysis.
Expression of proteins encoded by Epstein-Barr virus trans-activator genes depends on the differentiation of epithelial cells in oral hairy leukoplakia.
The Epstein-Barr virus (EBV) immediate early gene product BZLF1 was localized by indirect immunofluorescence to the cytoplasm of the basal epithelial layer at the lateral border and dorsum of tongue in human immunodeficiency virus-infected and -seronegative patients. Two biopsies of oral hairy leukoplakia revealed a sporadic cytoplasmic staining of the BHRF1 and BRLF1 gene products in the basal epithelial layer. The widespread presence of BZLF1 in the basal epithelial layer indicated that this cell layer contained EBV DNA and was probably directly infected by EBV. Nuclear localization of the immediate early and early gene products BZLF1, BHRF1, BRLF1, and BMLF1 was limited to oral hairy leukoplakia in human immunodeficiency virus-seropositive patients and revealed a codistribution with the virus capsid antigen. Our results indicate that the epithelium of the tongue is a potential reservoir for EBV and that in heavily immunocompromised patients EBV may move from the cytoplasm to the nucleus with increasing differentiation and be coactivated there during the terminal differentiation of epithelial cells at the lateral border and dorsum of tongue.
Comparative investigation of c-erbB2/neu expression in head and neck tumors and mammary cancer.
Normal tissues, primary tumors, and metastases of mammary and salivary glands and oral/laryngeal mucosa have been analyzed with Northern-blots employing 32P-labeled RNA probes for the expression of the neu oncogene. Neu oncogene expression of a mRNA species of 4.6 kilobases was found in all normal salivary (five) and mammary glands (four) as well as in two normal or inflamed samples of tongue mucosa. This expression was regarded as baseline activity of the neu gene for the respective tissues and was used as standard for the evaluation of benign and malignant tumors. None of 14 squamous cell carcinomas of the oral and laryngeal mucosa showed enhanced neu transcription level. Five fibroadenomas, one benign variant of phylloid tumor, one carcinosarcoma, and one of two proliferative fibrocystic diseases of the breast showed lacking or normal baseline expression of the neu oncogene, as did one monomorphous cystadenolymphoma of the parotid gland. In contrast, four parotid pleomorphic adenomas and one salivary gland adenocarcinoma showed enhanced neu expression. For mammary adenocarcinomas, increased neu oncogene expression concerned ten of 34 cases--all being variants of ductal carcinomas--and all metastases analyzed (six) deriving from three primaries. One adenoid cystic carcinoma also showed enhanced neu expression. Neu overexpression may reflect accidents of genomic reconstitutional events occurring regularly within the differentiation pathway of epithelial/myoepithelial cells. This assumption was supported by further immunohistochemical analysis which showed stainings of myoepithelial and myoepithelia-like cell populations in tumors, especially pleomorphic adenomas and adjacent normal-looking tissues.
Localization of malignant melanoma using monoclonal antibodies.
Finding a screening test to evaluate patients with cancer for occult metastatic disease, as well as imaging all known disease, is a goal of research efforts. Twenty-nine evaluable patients with deeply invasive (stage I), regional nodal (stage II), or systemic (stage III) melanoma underwent imaging by administration of a preparation of the antimelanoma antibody labeled with technetium 99m. Scan results indicated that 28 of 32 confirmed metastatic sites were imaged with this technique (88% sensitivity). Analysis of the individual positive sites revealed that nodal basins and visceral metastases accounted for the highest percentage of metastatic sites imaged, with 14 (88%) of 16 nodal basin metastases and all four visceral metastases being detected through imaging. Occult nodal disease was detected in the iliac nodal chain in two of the 29 patients. The imaging of benign tumors and nodal basins not containing disease accounted for a confirmed false-positive rate of 21%. Three (10%) of the 29 scan results were confirmed to be false-negative. In vivo tumor localization with monoclonal antibodies showed a sensitivity similar to that of other roentgenographic procedures for identifying metastatic disease and was useful in two of three patients in identifying occult iliac nodal disease, a region that is difficult to evaluate with physical examination and other imaging modalities.
Detection of submicroscopic lymph node metastases in patients with melanoma.
A cell culture technique was developed to investigate submicroscopic lymph node metastases in patients with stage 1 or 2 malignant melanoma. Lymph nodes were isolated from standard dissections and bivalved. Half of the node was evaluated by routine histopathologic examination, while the other half was processed and placed into tissue culture. Three hundred twenty-three lymph nodes were collected from 41 patients. The cell culture technique identified 155 of 323 lymph nodes containing micrometastases, while only 20 of 323 lymph nodes tested positive with routine histochemical processing. Nine patients were upgraded from stage 1 or 2 to stage 3 disease after micrometastases were identified in lymph node cultures. Identification of melanoma was confirmed by cytologic examination, immunohistologic staining, and the presence of GD3 ganglioside and 250-kd glycoprotein melanoma-associated antigens. This study provides evidence that the culture of lymph nodes is a sensitive method for the detection of micrometastases. In addition, this procedure may change prognosis and identify candidates for adjuvant therapies.
Mutational analysis of the putative effector domain of the GTP-binding Ypt1 protein in yeast suggests specific regulation by a novel GAP activity.
Ypt1p of Saccharomyces cerevisiae is a ras-related GTP-binding protein that fulfils an essential function in intracellular protein transport between the endoplasmic reticulum (ER) and the Golgi complex. Ypt proteins from yeasts and mammals that share an identical sequence in the region analogous to the ras effector domain are functionally interchangeable. We analyzed the function of the putative effector domain of yeast Ypt1p (amino acids 37-45) using site-directed mutagenesis and gene replacement. Four out of six point mutations leading to single amino acid substitutions (Y37F, S39A, T40S and V43E) did not cause any particular phenotype. ypt1(I41M) mutants were inviable whereas ypt1(D44N) mutant cells were temperature sensitive at 37 degrees C and accumulated core-glycosylated invertase at the nonpermissive temperature. This mutant also accumulated ER and small vesicles both at 25 degrees C and 37 degrees C. From porcine liver we identified and partially purified a GTPase-activating protein (yptGAP) that is similarly active with mouse ypt1p/rab1p and yeast Ypt1p but is inactive with H-ras protein as a substrate. Although none of the yeast ypt1 mutant proteins were significantly impaired in their ability to bind GTP, purified ypt1(D44N)p responded only partially and ypt1(I41M)p did not respond at all, to yptGAP. Thus we suggest that analogous to rasGAP/H-ras p21 interaction in mammalian cells, yptGAP is an intracellular target of Ypt1p, interacting with the effector domain and regulating its GTPase activity, and that this interaction is required for the functioning of yeast Ypt1p in intracellular protein transport.
Immunoelectron microscopy shows an atypical pattern and a quantitative shift of collagens type I, III and VI in oral Kaposi's sarcoma of AIDS.
The localization of collagen types I, III and VI in normal human alveolar and palatal mucosa and in oral Kaposi's sarcoma (KS) was studied by light microscopy and cryo-immunoelectron microscopy. Normal oral mucosa revealed two different types of organization. The upper connective tissue stroma contained a loose reticular network mainly composed of collagen types III and VI, while collagen type I immunostaining predominated in the deeper stroma. Ultrastructurally, in the KS tumour stroma, a loose pattern of individual thin collagen fibrils was noted. These often fanned out at their ends showing a filamentous substructure. The fibrils consisted predominantly of collagen type I similar to individual fibrils of normal oral mucosa. However, there was a marked loss of thick fibre bundles of collagen types I and III in KS compared with normal oral mucosa, whereas collagen type VI was markedly increased and found preferentially in clusters and strands around cross-striated fibrils that often spanned the distance between single collagen fibres. The abundance of collagen type VI in a pattern similar to early stages of wound healing suggests that the KS stroma resembles an early organizational stage of the interstitial and vascular extracellular matrix subject to a high rate of collagen turnover. This character of the KS stroma appears to result from a continuous auto-and paracrine stimulation of cell growth and collagen synthesis and provides an excellent model to study the structural arrangement of collagen type VI in relation to the fibrillar collagen types I and III.
Is sexual erotica associated with sexual deviance in adolescent males?
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Cardiohemodynamic and serum catecholamine response to surgical removal of impacted mandibular third molars under local anesthesia: a randomized double-blind parallel group and crossover study.
The aim of this study was to differentiate between the extent to which surgical stress and the epinephrine in local anesthetic solutions influence serum catecholamine, cAMP, and potassium levels, and contribute to changes in cardiohemodynamic parameters. One hundred sixty mg of articaine hydrochloride (4.0 mL of a 4% articaine hydrochloride solution) with two different epinephrine doses was injected into outpatients prior to removal of an impacted mandibular third molar in a randomized, double-blind parallel group and crossover design. The results showed that the amount of epinephrine absorbed from the intraoral injection site predominantly determined the serum epinephrine concentration. The anesthetic-induced increase in the serum epinephrine level did not correlate with changes in the cardiohemodynamic parameters under study at any time during the operative procedure. The serum cAMP changes correlated with those of epinephrine, whereas the serum potassium levels remained unchanged. The procedure of tooth extraction was a stressful event when the 1:200,000 epinephrine-containing anesthetic solution was used, showing that the risk of inducing a cardiovascular incident during oral surgery seems to be higher the greater the extent of operation and the lower the epinephrine dose in the anesthetic solution.