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Biomedical subjects

J Becker

Publications and source records attributed to J Becker.

At least 109 records · Page 6Linked to original sources
PubMed1995

Remarks on the vitality of the human cornea after organ culture.

The purpose of this study was to obtain further information on the viability of organ-cultured human cornea. We thus used a specific staining method for succinate dehydrogenase (SDH), which is located in the membrane system of vital mitochondria. We examined fresh and long-term-cultured human corneas. After an initial incubation period in dextran-free culture medium, corneas were stored in a medium containing dextran. With respect to different appearances of the SDH staining, minimal essential medium without dextran seems to have a positive effect on the condition of epithelial cells. After renewal of the medium, keratocytes showed a brief improvement followed by a delayed deterioration, while the endothelial cells were severely damaged. However, best results for all three cell types were observed on the fourth day in a medium containing dextran. We therefore conclude that these corneas were best suited for transplantation.

Adolescent↗
PubMed1995

High dose methotrexate infusion with leucovorin rescue for treatment of ectopic pregnancy.

The purpose of this article is to evaluate the effectiveness, side effects, and complications of high dose methotrexate infusion with leucovorin rescue in select patients with ectopic pregnancy. Between January 1991 and November 1994, 28 patients with ectopic pregnancies were prospectively treated with methotrexate (100 mg/m2 intravenous bolus followed by a 200 mg/m2 infusion over six hours) with leucovorin rescue. Twenty-seven of 28 patients (96%) were successfully treated. Only one patient (4%) required a second course of methotrexate to reach a normal hCG titer. One patient failed methotrexate infusion 45 days after treatment at a hCG titer of 12 mIU/mL. No Gynecologic Oncology Group grade 3 or 4 clinical, biochemical or hematologic toxicities occurred. Uterine bleeding and abdominal pain, not requiring transfusion or hospitalization, occurred in 71% and 56% of patients. The authors conclude that high dose methotrexate infusion with leucovorin rescue is a highly effective, well tolerated, nonsurgical treatment for select patients with ectopic pregnancy.

Abdominal Pain↗
PubMed1994

Heat-shock proteins as molecular chaperones.

Functional proteins within cells are normally present in their native, completely folded form. However, vital processes of protein biogenesis such as protein synthesis and translocation of proteins into intracellular compartments require the protein to exist temporarily in an unfolded or partially folded conformation. As a consequence, regions buried when a polypeptide is in its native conformation become exposed and interact with other proteins causing protein aggregation which is deleterious to the cell. To prevent aggregation as proteins become unfolded, heat-shock proteins protect these interactive surfaces by binding to them and facilitating the folding of unfolded or nascent polypeptides. In other instances the binding of heat-shock proteins to interactive surfaces of completely folded proteins is a crucial part of their regulation. As heat shock and other stress conditions cause cellular proteins to become partially unfolded, the ability of heat-shock proteins to protect cells against the adverse effects of stress becomes a logical extension of their normal function as molecular chaperones.

Animals↗
PubMed1994

Sonographic diagnosis of acute appendicitis in children.

The authors performed graded compression abdominal ultrasound (US) examinations in children with suspected acute appendicitis, whose clinical presentation was atypical. Abdominal US examination results were 95% accurate, far exceeding that reported for other imaging modalities. The sensitivity was 86%, the specificity was 98%, and the positive and negative predictive values were 96% and 94%, respectively. A positive sonogram made the likelihood of acute appendicitis 50 times greater compared with the pretest clinical impression. In addition, the use of US permitted identification of other pathological conditions that manifest similar symptoms and signs. The authors conclude that, with proper experience, US can be extremely useful in assisting the surgeon to markedly decrease the number of unnecessary appendectomy procedures, without increasing the risk of perforation.

Abdomen↗
PubMed1994

Enhancement of bone ingrowth into a porous hydroxylapatite-matrix using a resorbable polylactic membrane: an experimental pilot study.

The objective of this pilot study was to study bone ingrowth into porous hydroxylapatite (HA) blocks using a polylactic membrane for guided tissue regeneration. Porous HA blocks were placed on both sides of the mandible and of the ilium in five Göttingen minipigs. On one side a polylactic membrane was used to cover the blocks. After 5 months, the blocks with the membrane covering showed complete bony penetration of the HA matrix both in the mandible and the ilium. The blocks without the membrane covering showed substantially less and irregular bone ingrowth after placement on the mandible and poor ingrowth after placement on the ilium. The newly formed bone in the blocks from the ilium showed a cancellous structure while bone tissue inside the blocks from the mandible exhibited a dense cortical appearance. The polylactic membrane was nearly completely degraded at the time of investigation.

Animals↗
PubMed1994

Odontogenic myxoma--characterisation of the extracellular matrix (ECM) of the tumour stroma.

In order to elucidate the origin of the odontogenic myxoma, the composition and the structural organisation of the extracellular matrix (ECM) of this tumour were characterised. Collagen type I, VI, procollagen type III, undulin, tenascin and fibronectin were demonstrated in biopsy material of 4 cases by polyclonal antibodies. The tumour stroma showed a pronounced reaction for collagen type I. Fibroblasts displayed an intense intracytoplasmatic reaction for procollagen type III, and collagen type I was not found in the fibroblasts of the adjacent normal oral mucosa. In contrast to the surrounding connective tissue, label for collagen type VI was weak, as was the reaction for fibronectin and tenascin. Undulin was almost undetectable. The immunohistochemical results suggest that the odontogenic myxoma is characterised by an as yet unobserved structural organisation of ECM proteins, a secretion defect of fibrillar collagens type I and III with no resemblance to physiological tooth development.

Adult↗
PubMed1994

Perceptions of parental and peer attachments by women with mood disorders.

The relationship between perceptions of parental and peer attachments at various ages and adult mood disorders was examined in 156 women classified as having bipolar disorder or unipolar depression or as nonpsychiatric controls. Nonpsychiatric controls reported a decreased attachment to their parents over time, but they also reported an increased closeness to their mothers in adulthood following a distant adolescence. Never hospitalized, moderately depressed subjects showed a similar trend toward decreased relatedness, but moderately depressed subjects did not report reestablishment of a close relationship with their mothers after adolescence. Severely depressed and bipolar subjects reported little attachment to their mother at all ages. Bipolar subjects also reported little connectedness to their fathers throughout their lifespan and severely depressed women felt less attached than nonpsychiatric controls to peers during development. None of the psychiatric groups reported difficulties with parental overcontrol.

Adult↗
PubMed1994

Dependency, self-criticism, and perceptions of socialization experiences.

This study explored the relationship of dependency and self-criticism to perceptions of socialization experiences using 132 bipolar, nonbipolar depressed, and nonpsychiatric control female subjects. After controlling for level of depression and diagnosis, dependency was related to a distant relationship with fathers during development and was marginally related to perceptions of increased parental attention and overindulgence. Self-criticism was related to perceptions of difficulties in the quality of affective bonds with fathers and peers during childhood and was related marginally to perceptions of increased paternal power and control during development. No unique socialization experiences were associated with high dependency and self-criticism jointly, but women with both dispositional tendencies were likely to be severely depressed.

Adult↗
PubMed1994

Distribution of procollagen type III, collagen type VI and tenascin in oral submucous fibrosis (OSF).

The distribution of procollagen type III, collagen type VI and tenascin was studied in biopsy specimens from the buccal mucosa of 19 Indian women with confirmed oral submucous fibrosis (OSF) using the immunogold-silver staining technique. Immunohistochemistry revealed a loss of stainable procollagen type III and collagen type VI in the fibrotic zones of oral submucous fibrosis compared to normal oral mucosa. Tenascin was noted only very faintly at the subepithelial basement membrane. The present study showed that procollagen type III and collagen type VI in OSF were expressed in a specific pattern which allows a clear differentiation between fibrotic areas and adjacent apparently normal connective tissue stroma. Loss of procollagen type III, and therefore a probable predominance of collagen type I in collagen fiber bundles, and an almost complete loss of collagen type VI might explain the stiffness of the oral mucosa in patients with OSF. The immunohistochemical findings provided evidence that the process of fibrosis starts in the deeper subepithelial connective tissue stroma and not close to the subepithelial basement membrane. Further studies are required to determine whether OSF is due to increased or altered synthesis and deposition of extracellular matrix proteins, altered fibrolysis or both.

Adult↗
PubMed1994

In situ detection of PCR-amplified HIV-1 nucleic acids in lymph nodes and peripheral blood in patients with asymptomatic HIV-1 infection and advanced-stage AIDS.

This study determined the in situ detection rate of polymerase chain reaction (PCR)-amplified human immunodeficiency virus type 1 (HIV-1) DNA and RNA in lymph nodes and peripheral blood CD4+ cells in six patients with asymptomatic HIV-1 infection and from six people who died of advanced AIDS. The lymph nodes of patients with asymptomatic infection showed expanded germinal centers where, on average, 20% of the CD21+ dendritic cells contained HIV-1 DNA. From 5 to 80% of the CD4+ cells in these lymph nodes contained HIV-1 DNA, as compared with 1-11% of the CD4+ peripheral blood mononuclear cells. The infection in most cells was latent in the asymptomatic group. In contrast, the lymph nodes of patients with advanced AIDS showed marked depletion of both dendritic and CD4+ cells. The majority of the remaining CD4+ cells in the lymph nodes and blood showed PCR-amplified viral DNA and cDNA sequences suggesting the presence of genomic and multiple spliced transcripts. It is concluded that asymptomatic HIV-1 infection is associated with a wide range of latent to active viral-positive CD4+ lymphocytes and dendritic cells in the lymph nodes. Progression to AIDS is characterized by active viral replication in many of the remaining CD4+ cells in the lymph nodes and blood.

Acquired Immunodeficiency Syndrome↗
PubMed1994

The influence of the cause of death and age on human corneal metabolism.

PURPOSE: Little is known about the metabolic status of human corneas before transplantation. The authors attempted to determine the influence of both cause of death and age on the corneal metabolism. METHODS: Adenosine-triphosphate (ATP), adenosine-diphosphate (ADP), glucose, and lactate were measured in the stroma and endothelium of 30 human corneas. The corneas were divided into four groups according to cause of death and four groups according to age. Corneas from donors with diabetes were excluded. RESULTS: Corneas from patients who died suddenly--because of cardiac infarction, for example--have good metabolic status even 24 hours after death. In corneas of patients with cancer or sepsis, the metabolism has run down. In comparison, corneas from patients with cancer are in better metabolic condition than those from donors with sepsis because they have adapted to catabolism. Corneas donated from patients with renal insufficiency show results somewhere in between. Statistical evaluation revealed significant differences in ATP concentrations for corneas from donors who died suddenly and from patients with renal insufficiency compared to corneas from patients with sepsis. It could be shown that glucose concentrations as a resource for metabolism increase with age. The best ATP-ADP ratios were found in the group of 40- to 59-year-old donors. Nevertheless, differences between the age groups were not statistically significant. CONCLUSION: From our results it can be concluded that the cause of death and systemic metabolism have an influence on corneal metabolism. Results concerning donor age reflect the well-known fact that donor age has no influence on the quality of keratoplasty material.

Adenosine Diphosphate↗
PubMed1994

HIV-1 nucleic acids localize to the spermatogonia and their progeny. A study by polymerase chain reaction in situ hybridization.

The purpose of this study was to determine the histological distribution of in situ polymerase chain reaction (PCR)-amplified HIV-1 nucleic acids in the male genital tract to elucidate the mechanism of sexual transmission of AIDS. Viral DNA was detected in the testicular tissue of 11 of 12 men with HIV-1 infection using the PCR in situ hybridization technique. The amplified viral DNA localized to many spermatogonia, spermatocytes, and rare spermatids. Relatively few viral infected macrophages were noted, mostly in the prostate. The viral infection was activated given the presence of cDNA sequences consistent with genomic and multiple spliced transcripts as determined by reverse transcription in situ PCR. PCR-amplified viral nucleic acids were not detected in the epithelial of the prostate, epididymis, seminal vesicles, or penis in men with AIDS nor in any genital tract tissues from three boys who died of AIDS acquired in utero. The demonstration that HIV-1 selectively infects the spermatogonia and their progeny suggests that this may serve as a primary source of venereal spread of the virus. Concomitant destruction of these cells by HIV-1 may also explain the marked inhibition of spermatogenesis and severe atrophy that characterizes the testes in AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Immunological reactions against PMMA lens material?

We investigated the kind of reactions that occur after injection of a PMMA lens powder into the back skin of rabbit. The lens powder was suspended in NaCl and incomplete Freund's adjuvant to reinforce the immunological reaction. The ELISA test was carried out to detect antibodies against the lens material as a whole and against the UV absorber Tinuvin in particular. We also performed histological and immunohistochemical examinations of the back skin. We did not detect antibodies against either the lens material or against Tinuvin. Histological examination showed a foreign-body or delayed allergic reaction against the lens material. Lymphocytes surrounding the PMMA were found to be mainly of the T-type, which supports the results of the ELISA test.

Animals↗
PubMed1993

Genetic mediation of infanticide and parental behavior in male and female domestic and wild stock house mice.

Infanticide is a reproductive strategy found in many mammals, especially rodents. The proportion of male and female house mice (Mus domesticus) that are either infanticidal or noninfanticidal is strain specific and varies widely from stock to stock. Male house mice also show strain-specific variation in the behavioral mechanisms that inhibit infanticidal individuals from killing their own offspring. The adult offspring generated from reciprocally crossed CF-1 and Wild stock house mice were tested for their behavior toward newborn pups. In male CF-1 x Wild hybrids, the proportion of infanticidal and noninfanticidal males matched with their maternal phenotype, whereas female CF-1 x Wild hybrids exhibited a proportion of behaviors typical of the CF-1 phenotype, regardless of their mother's genotype. Our results suggest three conclusions: first, that infanticide is a highly labile and heritable behavior in both sexes; second, that there is a sex difference in the genetic substrate that regulates the inheritance of infanticidal behavior; and third, that selection pressures in male mice may operate independently on the mechanisms that promote spontaneous infanticidal behavior versus the mechanisms that inhibit infanticide.

Agonistic Behavior↗
PubMed1993

Distribution of immunocompetent cells in oral Kaposi's sarcoma (AIDS).

Fifteen biopsy specimens of oral AIDS-associated Kaposi's sarcoma (KS), 19 biopsy specimens of uninvolved oral mucosa of HIV-seropositive patients (HIV+) and 22 biopsy specimens of oral mucosa of HIV-seronegative persons (HIV-) were analysed for the distribution of CD4+ and CD8+ lymphocytes and HLA-DR+ cells. The results were statistically evaluated. According to their clinical appearance KS were classified as flat lesions (n = 10) or exophytic tumours (n = 5). KS lesions of both clinical groups as well as uninvolved mucosa of HIV+ patients revealed infiltration with CD4+ cells. In flat, patch-like KS there was a marked increase of CD8+ cells compared to HIV- mucosa, while their numbers decreased in later tumour stages. In both, flat and exophytic KS the number of HLA-DR+ cells was significantly higher than in uninvolved mucosa of HIV+ and HIV- persons. These findings may reflect the local influence of KS growth factors on the inflammatory reaction in the setting of systemic immunosuppression.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Outpatient management with oral corticosteroid therapy for obstructive conditions in chronic granulomatous disease.

We report the outpatient management of three patients with X-linked chronic granulomatous disease, two of whom had episodes of gastric outlet obstruction and another, urinary bladder obstruction. These obstructive conditions were successfully treated with 2-week courses of orally administered corticosteroids with or without the addition of orally administered clindamycin. There were no infectious or other adverse reactions.

Administration, Oral↗
PubMed1993

Semiotic aspects of cognitive development: illustrations from early mathematical cognition.

The premise of this article is that cognitive development involves both conceptual and semiotic achievements. From this perspective, the authors emphasize the distinctness of the semiotic issues and develop a differentiated appreciation of semiotic aspects of cognition, particularly in the field of elementary mathematical cognition. The authors provide semiotic analyses of the differences between counting, adding, and multiplying and of the conventional place-value sign system. The authors introduce the concept of the field of reference of a sign, the differentiation of the field into foreground and background, and the dynamics within the field of reference. Finally, the authors relate these ideas to the dynamics between two dimensions of semiotic relations: the sign-referent dimension and the sign-sign dimension.

Child↗