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Biomedical subjects

D Becker

Publications and source records attributed to D Becker.

At least 55 records · Page 3Linked to original sources
PubMed1989

Transforming activity of nasopharyngeal carcinoma DNA detectable in mouse JB6 cells.

A JB6 mouse epidermal recipient cell line has been used to detect nasopharyngeal carcinoma (NPC) DNA-associated transforming activity that is not detectable in the NIH 3T3 focus assay. NPC DNA showed both transforming activity and activity for transferring sensitivity to tumor-promoter-induced neoplastic transformation, assayed in 2 different variants of mouse JB6 cells. Comparison of DNAs from various NPC sources that did or did not harbor EBV DNA and that varied in degree of differentiation showed similar transforming activities and similar activities for transferring promotion sensitivity. Thus both a NPC DNA-associated promotion sensitivity and an oncogenic activity function independently of concurrent EBV gene expression.

Animals↗
PubMed1989

Proliferation of human malignant melanomas is inhibited by antisense oligodeoxynucleotides targeted against basic fibroblast growth factor.

Human malignant melanomas, unlike normal melanocytes, can proliferate in the absence of exogenous basic fibroblast growth factor (bFGF). Exposure of primary melanomas in the vertical growth phase and metastatic melanomas to antisense oligodeoxynucleotides targeted against three different sites of human bFGF mRNA inhibited cell proliferation and colony formation in soft-agar. In contrast, exposure of human bFGF sense or antisense oligonucleotides complementary to human beta-nerve growth factor or insulin-like growth factor I mRNA had no such effects. These experiments indicate that activation of the bFGF gene may play an important role in the progression from melanocytic precursor lesions to malignant melanoma.

Antineoplastic Agents↗
PubMed1989

Spontaneous whole blood platelet aggregation in insulin-dependent diabetes mellitus: an evaluation in an epidemiologic study.

Spontaneous whole blood platelet aggregation (SWBPA) was examined in a case-control study, comparing a consecutive series of IDDM subjects (n = 30) to age, and sex matched controls. Subjects were free of platelet altering medications. Platelet aggregation was measured by the percent fall in single platelet count after 15 minutes of both shaking (SK) and magnetic stirring (ST). IDDM subjects showed a significantly greater percent fall in SK (means = 12.1) and ST (means = 34.0) compared to controls (SK means = 8.4, p less than 0.01; ST means = 24.3, p less than 0.05). Long-term repeat testing on 15 subjects (diabetics and non-diabetics) up to 4 months apart showed a correlation of 0.7 for SK, p less than 0.01 but only 0.4 for ST. In a further series of IDDM subjects (n = 176) those with macrovascular disease (n = 27) showed significantly greater percent fall in SK (p less than 0.05), and ST (p less than 0.05). We conclude that SWBPA is a simple useful epidemiological technique (shaking being more repeatable than stirring) which relates to both diabetes and macrovascular disease.

Adolescent↗
PubMed1989

Multiple genes are transcribed in Hordeum vulgare and Zea mays that carry the DNA binding domain of the myb oncoproteins.

cDNA clones were isolated from tissue specific cDNA libraries of barley and maize using as a probe the cDNA of the maize gene C1, a regulator of anthocyanin gene expression. C1-related homology for all of the four cDNAs characterized by sequence analysis is restricted to the N-terminal 120 amino acids of the putative proteins. This region shows striking homology to the N-proximal domain of the myb oncoproteins from vertebrates and invertebrates. Within the myb proto-oncogene family this part of the respective gene products functions as a DNA binding domain. Acidic domains are present in the C-proximal protein segments. Conservation of these sequences, together with the genetically defined regulator function of the C1 gene product, suggest that myb-related plant genes code for trans-acting factors which regulate gene expression in a given biosynthetic pathway.

Amino Acid Sequence↗
PubMed1989

Loss of heterozygosity at chromosomal regions 3p and 13q in non-small-cell carcinoma of the lung represents low-frequency events.

It was recently reported that loss of heterozygosity occurred at the chromosomal region 3p in small-cell as well as in non-small-cell carcinoma of the lung. A recent report also indicated genetic changes involving sequences on chromosomes 13q and 17p in small-cell and in non-small-cell carcinomas. In the present study normal and tumor DNAs representing mostly adeno-and squamous cell carcinomas of the lung were examined for loss of heterozygosity on chromosomes 3p, 13q, 11p, and 1p. With the exception of two non-small-cell carcinomas which demonstrated loss of alleles on chromosome 3p and one small-cell carcinoma which demonstrated loss of heterozygosity at chromosome 3p as well as at 13q, evidence for loss of alleles on chromosomes 3p, 13q, 11p, and 1p could not be obtained in greater than 75% of the non-small-cell carcinoma DNAs tested. Given this result it appears unlikely that a recessive gene is located on either chromosome 3p or 13q in the majority of non-small-cell carcinomas of the lung.

Alleles↗
PubMed1988

Thiol peroxyl radical formation from the reaction of cysteine thiyl radical with molecular oxygen: an ESR investigation.

Using Electron Spin Resonance (ESR) spectroscopy, we have identified the cysteine thiol peroxyl radical (CysSOO.) at low temperatures in two aqueous glasses. This radical shows a typical peroxyl radical ESR spectrum, but unlike carbon-based peroxyl radicals has a violet color (lambda max = 540 nm) and forms a new radical showing a singlet ESR spectrum when photobleached with visible light. The cysteine peroxyl radical reacts to form the cysteine sulfinyl radical (CysSO.) in the glass which allows warming to 165K. 17O isotopic substitution studies indicate dissolved molecular oxygen is the source of oxygen in CysSOO.. Anisotropic g-values and the parallel anisotropic 17O hyperfine couplings for this radical are reported.

Cyclic N-Oxides↗
PubMed1988

Effect of chronic haloperidol treatment on peripheral benzodiazepine binding sites in cerebral cortex of rats.

The effects of 21 days of haloperidol treatment on central benzodiazepine (BZ) receptors in the cerebral cortex of rats and on peripheral-type BZ binding sites (PBS) in the cerebral cortex and heart of rats were studied. Neuroleptic treatment did not affect the maximal binding capacity or the affinity of the central BZ receptor to 3H-flunitrazepam. Chronic haloperidol treatment resulted in a significant increase of 38% in PBS density in the cerebral cortex, with no alteration in PBS density in the heart. No alteration in PBS affinity for its ligand 3H-PK 11195 was observed, either in the cerebral cortex or in the heart. The modulatory effect of chronic haloperidol administration on PBS density in the brain may be related to some of the neurobehavioral or hormonal effects of the drug.

Animals↗
PubMed1988

An ESR investigation of the reactions of glutathione, cysteine and penicillamine thiyl radicals: competitive formation of RSO., R., RSSR-., and RSS(.).

The reactions of the cysteine, glutathione and penicillamine thiyl radicals with oxygen and their parent thiols in frozen aqueous solutions have been elucidated through electron spin resonance spectroscopy. The major sulfur radicals observed are: (1) thiyl radicals, RS.; (2) disulfide radical anions. RSSR-.; (3) perthiyl radicals, RSS. and upon introduction of oxygen; (4) sulfinyl radicals, RSO., where R represents the remainder of the cysteine, glutathione or penicillamine moiety. The radical product observed depends on the pH, concentration of thiol, and presence or absence of molecular oxygen. We find that the sulfinyl radical is a ubiquitous intermediate in the free radical chemistry of these important biological compounds, and also show that peroxyl radical attack on thiols may lead to sulfinyl radicals. We elaborate the observed reaction sequences that lead to sulfinyl radicals, and, using 17O isotopic substitution studies, demonstrate that the oxygen atom in sulfinyl radicals originates from dissolved molecular oxygen. In addition, the glutathione thiyl radical is found to abstract hydrogen from the alpha-carbon position on the cysteine residue of glutathione to form a carbon-centered radical.

Chemical Phenomena↗
PubMed1988

Growth and phenotypic characteristics of human nevus cells in culture.

Nevus cells were isolated from the three cutaneous components, epidermis, basal layer, and dermis, of nonmalignant pigmented lesions and were cultured separately in the presence or absence of the phorbol ester 12-0-tetradecanoyl phorbol-13-acetate in medium that supports the rapid proliferation of melanocytic cells. The separation procedure used provided cultures that were essentially free from normal melanocytes (dermis) or fibroblasts (epidermis). In short term culture, nevus cells of all skin compartments expressed markers associated with differentiated melanocytes, such as presence of premelanosomes and melanosomes and elevated tyrosinase levels. Nevus cells also expressed melanoma-associated antigens, such as NGF-receptor, transferrin-related p97, proteoglycan, and HLA-DR as detected with monoclonal antibodies. After several subpassages, cells showed a decreased expression of melanoma-associated antigens, decreased tyrrosinase levels, and melanosomes could no longer be detected. Morphologically, these cells were similar to fibroblasts. The disappearance of melanoma-associated cell surface antigens was concomitant with the appearance of a melanocyte-associated 145 kd protein that might serve as a marker of fibroblast-like differentiation in nevus cells and normal melanocytes. Nevus cell cultures grown in the presence of 12-0-tetradecanoyl phorbol-13-acetate maintained a stable differentiated phenotype throughout their lifespan. As reported earlier, nevus cells in culture, irrespective of the presence or absence of 12-0-tetradecanoyl phorbol-13-acetate, have a finite lifespan in vitro, grow anchorage-independent in soft agar, but do not form tumors when xenografted to nude mice. These studies demonstrate that nevus cells isolated from the epidermal, basal layer, and dermal components of lesional skin can serve as models to characterize the initial steps of tumor progression in a human cell system.

Adolescent↗
PubMed1988

Intraoperative development of contralateral epidural hematoma during evacuation of traumatic extraaxial hematoma.

Intraoperative development of an epidural hematoma contralateral to a craniotomy for acute traumatic extraaxial hematoma has been previously reported. This entity, however, has never been distinctly defined and differentiated from either the delayed or the bilateral acute epidural hematoma. We present 3 new cases of intraoperative contralateral acute epidural hematoma and review the 14 previously reported cases. The typical clinical presentation is a severe head injury with an acute extraaxial hematoma and severe ipsilateral brain displacement during craniotomy. If brain displacement is not noted at craniotomy, then the contralateral hematoma is manifested by immediate postoperative neurological deterioration or intractable elevated intracranial pressure. The presence of any of these signs makes an immediate postoperative CT scan or burr holes contralateral to the original craniotomy mandatory for early diagnosis. In addition to defining "intraoperative contralateral epidural hematoma," stricter definitions of the terms "delayed epidural hematoma" (no hematoma present on the initial CT scan but one present on a later scan) and "bilateral epidural hematomas" (present on the initial scan) are proposed.

Adolescent↗
PubMed1988

[A sparing operation in fracture of the radius head using pinning with resorbable Biofix material].

The incidence of dislocated, subcapitular radial head fracture is discussed. The traditional treatment of this fracture dictates resection of the radial head which induces disturbances of the elbow and wrist. The author has used the bio-degradable material BIOFIX as a 4.5 mm thick pin for internal splinting of the fracture. Early mobilization is possible and later no metal has to be removed. By demonstrating one case of treatment by BIOFIX the author shows a new chance for conservation of the radial head and thereby of the function of the joints.

Adult↗