Search PubMed⌕ Search

Biomedical subjects

R L Teplitz

Publications and source records attributed to R L Teplitz.

At least 55 records · Page 3Linked to original sources
PubMed1985

Discrimination among the human beta A, beta S, and beta C-globin genes using allele-specific oligonucleotide hybridization probes.

Synthetic nonadecanucleotides complementary to the human beta A-, beta S-, or beta C-globin sequences were used as hybridization probes to screen human genomic DNA samples for these genes. The oligonucleotides were 32P-labeled and used as probes to genotype restriction endonuclease digests of human genomic DNA. The data obtained show that hybridization with oligonucleotide probes, unlike restriction fragment length polymorphism (RFLP) analysis or direct restriction enzyme digestion, can be used to directly distinguish among the three alleles of beta-globin, beta A, beta S, and beta C, when present either in one (heterozygous) or two copies.

Alleles↗
PubMed1984

Metaphase synchronization and chromosome preparation from the OK opossum cell line having a potentially isolatable X chromosome.

As part of a study on X chromosomes, metaphase cell synchrony and chromosome isolation methods were developed for the opossum (Didelphis virginiana) kidney epithelial cell line (OK). The cell synchrony yielded large amounts of metaphase cells using a relatively simple method in which a key feature was a calcium- and magnesium-free balanced salt wash. A neutral pH chromosome isolation method was developed for the kidney epithelial cells, because they were somewhat difficult to disrupt fully by other methods. FACS IV flow microfluorometric analysis of OK chromosomes confirms a clear difference between the sizes of opossum X chromosomes and autosomes.

Animals↗
PubMed1984

A family of epidermoid lung cancer models.

A method of sustained release implantation has been developed whereby Silastic cylinders, impregnated with benzo[alpha]pyrene (BP) or methylcholanthrene (MCA) each at 2% (low dose) and 10% (high dose) concentrations, were inserted into the bronchus intermedius of hamsters. High-dose BP and MCA, and low-dose MCA had first-order exponential release rates: the half-time of release was 40 days for high-dose BP, 30 days for high-dose MCA, and 165 days for low-dose MCA. Release rate of low-dose BP was a second-order function: half-time of release was 40 days. Atypical squamous metaplasia was noted by 4 weeks in more than 65% of hamsters after insertion of each high-dose carcinogen but in less than 30% with the low-dose carcinogens. Carcinoma in situ was noted approximately 8 weeks after high-dose BP and 19 weeks after low-dose BP. At about 15 to 17 weeks after a high-dose carcinogen, 64% of animals had invasive epidermoid cancer, whereas after a low-dose carcinogen, only 21% did. After 25 weeks of exposure to a high-dose carcinogen, more than 85% of hamsters had invasive epidermoid cancer; up to 52 weeks were required for invasive epidermoid cancer to develop in 30% after a low-dose carcinogen. Measured by image analysis, nuclear deoxyribonucleic acid content of cells with severe atypical squamous metaplasia was greater than tetraploid (mean +/- standard deviation [SD], 3.77 +/- 1.4), whereas cells with invasive epidermoid cancer were suprahexaploid (mean +/- SD, 6.48 +/- 3.6). These differences are significant (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Quantitative DNA values in bronchogenic carcinoma.

Quantitative DNA analysis of neoplastic cells often produces standard deviations that are nonsymmetrical; attempts at correcting this characteristic by mathematical means have been only partially successful. We examined the sources of the skewed values and the appropriate means for their "correction." The analysis showed that the deviation from symmetry lies within several biologic parameters. These deviations from symmetry may, therefore, teach something of value regarding the biologic process under study instead of requiring the application of arbitrary "corrections."

Carcinoma, Bronchogenic↗
PubMed1983

Prenatal diagnosis of beta-thalassemia. Detection of a single nucleotide mutation in DNA.

We investigated a method employing synthetic oligonucleotides for the prenatal diagnosis of beta-thalassemia due to a single nucleotide mutation. The beta 0 thalassemia we tested is produced by a nonsense mutation and is commonly found in Sardinia and other parts of the Mediterranean. In this DNA lesion, the glutamine codon CAG at the beta 39 position is mutated to TAG, which results in a stop codon and premature termination of the beta-globin chain. We synthesized two oligonucleotides: one homologous to the normal beta A gene and the other to the beta 0 thalassemia gene at the beta 39 location. The oligonucleotides were labeled with 32P and used as hybridization probes for normal and thalassemic DNA. The beta A probe hybridized only to the normal DNA, and the beta-thalassemia probe only to thalassemic DNA, thus providing a technique for direct demonstration of the mutation. The method is sensitive enough to be applied directly to DNA that is isolated from uncultured cells obtained from only 20 ml of amniotic fluid as early as the 16th gestational week.

Amniocentesis↗
PubMed1983

Quantitative DNA. Comparative studies of a cellular marker for bronchogenic carcinoma.

During the course of induction of bronchogenic carcinoma in a colony of standard-bred beagles, serial cytologic and biopsy material was obtained under direct bronchoscopy. Cytological changes followed the sequence from metaplasia to carcinoma, closely simulating those features observed in humans, but with subtle differences characterized as species variations. Quantitative DNA done by image analysis correlated directly with the severity of cytologic atypia and also corresponded well with data obtained from humans. Equivalent studies in human bronchogenic carcinoma have shown similar results and strongly suggest that graded hyperploidy accurately reflects atypia in the lung and qualifies as an interspecies tumor marker.

Animals↗
PubMed1983

Detection of teratogens in the Drosophila embryonic cell culture test: assay of 100 chemicals.

An in vitro assay of teratogenesis has been developed that utilizes Drosophila embryonic cell cultures. The endpoint selected in assessing the teratogenic potential of any substance involves detection of interference with normal muscle and/or neuron differentiation. In the validation phase of this project, 100 chemicals were tested. With drugs for which extensive reliable mammalian data are available, the results in the Drosophila assay equate rather favorably with those observed in animals and humans (i.e., a low percentage of false positives and false negatives has been obtained). In an effort to determine if strain differences exist and also to establish that the system shows a dose response, cultures from three wild-type Drosophila strains (Canton S, Canton S109, and Oregon R) were tested. Dose-response differences were observed when diethylstilbestrol, diphenylhydantoin, imipramine, testosterone, and tolbutamide were added to the cultures. These results suggest that the Drosophila assay, with further testing and refinements, might be capable of identifying agents of high teratogenic potential by their effect on neurons and muscle differentiation. Furthermore, sensitive strains might be used to study mechanisms of abnormal development and gene involvement in teratogenic resistance.

Animals↗
PubMed1983

Detection of sickle cell beta S-globin allele by hybridization with synthetic oligonucleotides.

Two 19-base-long oligonucleotides were synthesized, one complementary to the normal human beta-globin gene (beta A) and one complementary to the sickle cell beta-globin gene (beta S). The nonadecanucleotides were radioactively labeled and used as probes in DNA hybridization. Under appropriate hybridization conditions, these probes can be used to distinguish the beta A gene from the beta S allele. The DNA from individuals homozygous for the normal beta-globin gene (beta A beta A) only hybridized with the beta A specific probe; the DNA from those homozygous for the sickle cell beta-globin gene (beta S beta S) only hybridized with the beta S specific probe. The DNA from heterozygous individuals (beta A beta S) hybridized with both probes. This allele-specific hybridization behavior of oligonucleotides provides a general method for diagnosis of any genetic disease which involves a point mutation in the DNA sequence of a single-copy gene.

Alleles↗
PubMed1983

Monoclonal autoantibody directed toward histone and capable of inducing LE cell formation.

LE cell formation is one feature of systemic lupus erythematosus exhibited by virtually all mice of the NZB/NZW strain and is the result of accumulation of antibodies directed against components of cell nuclei. A hybrid cell line which produces antibodies capable of inducing LE cell formation in vitro has been isolated in a hybridoma fusion using the splenocytes of unimmunized NZB/NZW mice. These monoclonal autoantibodies provide an intense staining of the chromatin in cells of a number of divergent species and tissues. They bind strongly to the histone rich (2 M NaCl) fraction of extracted, isolated nuclei. Further analyses using the antibodies in immune precipitations and in antibody labeling of capillary blots on nitrocellulose sheets of calf thymus histone demonstrate that the antibodies are directed against histones and are capable of reacting with H1, H2a, H2b, H3, and H4 histones individually. In contrast to human autoantibodies with histone specificity, no cross-reactivity of this monoclonal autoantibody with the lymphocyte surface could be detected by either immunofluorescence or immunoelectron microscopy.

Animals↗
PubMed1983

Quantitative DNA determination by image analysis. II. Application to human and canine pulmonary cytology.

Comparative DNA measurements in human and canine preneoplastic and neoplastic tracheobronchial cells were made with the application of computerized image analysis. Canine studies demonstrated that the sequence of cellular events that precede epidermoid lung cancer simulates precisely the progression observed in humans. DNA studies concomitantly confirmed that there is a stepwise increase in DNA content with advancing nuclear atypia in metaplastic respiratory cells in both species. All carcinomas, regardless of histologic type, were significantly hyperploid to aneuploid (4c to 6c). Small-cell carcinoma exhibited a narrow modal distribution in the 4c region. The uniformity of the cytologic and quantitative DNA changes among these disparate species tends to confirm that humans and canines share biologic characteristics in bronchogenic carcinogenesis. The quantitative DNA measurements provide an objective cellular marker and may be used clinically for diagnostic purposes.

Adenocarcinoma↗
PubMed1983

Typical and atypical carcinoids within the pulmonary APUD tumor spectrum.

The behavior of pulmonary APUD tumors is not constant; management is controversial, and morphology has reached its limit as a tool for prognostic assessment and therapeutic planning. We have studied 24 patients with carcinoids; 17 patients with typical carcinoids presented with Stage I disease, but one patient later died most probably of small cell undifferentiated lung cancer (SCLC). Seven patients with atypical carcinoids included three with Stage III cancers, one patient with simultaneous bilateral carcinoids, and one patient with simultaneous adenocarcinoma. Of 17 patients with typical carcinoids, 16 or 92% are disease free or died of unrelated causes. Of seven patients with atypical carcinoids, five or 71% are disease free. Tumor doubling time of atypical carcinoids, was 79.6 months (45 to 120) or six times shorter than that of typical carcinoids (p less than 0.05). Two of the three deaths from cancer were probably from SCLC and one from a synchronous adenocarcinoma. Review of diagnostic material from 12 patients with SCLC who survived a mean of 41 months (24 to 134) showed that diagnosis had rested on cytology alone in four patients and that, in seven patients, the quality or extent of the original diagnostic material was adequate to make the diagnosis of a malignant tumor but inadequate to permit reclassification. Tumor cells from 11 patients with carcinoids (seven typical and four atypical) and 28 patients with SCLC had DNA measurement by image analysis. The mean DNA content of typical and atypical carcinoids and SCLC is 1.17, 1.25, and 1.94 respectively (p less than 0.001). These findings strongly suggest a relationship between DNA content and atypia or malignancy in APUD lung tumors. We conclude that there are at least two levels of virulence among carcinoids represented by typical and atypical carcinoids. The prognosis for treated Stage I typical and atypical carcinoids is excellent. When deaths occur, they are from systemic cancer. Current evidence indicates that DNA measurements by image analysis may help to discriminate levels of malignancy among APUD pulmonary cancers and thereby help to clarify therapeutic controversies.

Adenocarcinoma↗
PubMed1983

Intraoperative cytodiagnosis of lung tumors by needle aspiration.

Rapid-stain cytologic evaluation of needle aspirates are a recent adjunct to diagnosis and staging of lung neoplasms. The benefits of this approach include ease of sampling from deep and remote lesions and the fact that the results are generally available within 10 minutes. In the past 2 years, we did 187 needle aspirations for cytopathological evaluation in 70 patients at 51 thoracotomies and 21 mediastinoscopies. The cytologic findings from aspirates of lymph nodes, mediastinal masses, and intrapulmonary lesions were compared with diagnosis obtained by histopathological techniques. Quick-stain cytopathological evaluation discriminated cancer among all 55 lung masses from which aspirates were taken; specific diagnosis as to the type of neoplasm, lymphoproliferative disorder, or infection was achieved in 60 of 70 patients (85%). We conclude that intraoperative needle aspirations for cytologic evaluation facilitates the practice of modern general thoracic surgery.

Adult↗
PubMed1982

Fetal proteins in ataxia-telangiectasia.

Ataxia-telangiectasia (AT) is a genetic disorder of unknown pathogenesis, with primary effects on the immune and nervous systems. The presence of a fetal-like thymus and elevated alpha-fetoprotein (alpha FP) levels in patients with AT suggests that suppressed mesodermal development may be a factor in the development of this disease. We investigated this hypothesis by using electrophoretic and quantitative analyses to test for the presence of other fetal proteins in mesodermal tissues. With the exceptions of alpha FP and carcinoembryonic antigen, all other proteins assessed in these patients were present at levels or in isozymic patterns characteristic of a normal, nonfetal state.

Adult↗
PubMed1982

Use of Drosophila embryo cell cultures as an in vitro teratogen assay.

An in vitro assay has been developed for detecting teratogens by adding them to primary cultures of embryonic Drosophila cells and analyzing the degree of change in cell differentiation and tissue formation. Cultures are scored by an automated image analysis system that counts the number of myotubes and ganglia in culture. A decrease in their number compared to controls is taken as an indication of teratogenicity. In the group of 100 drugs and chemicals examined thus far in this assay, a high correlation with known teratogenic activity has been obtained with few false-positives or false-negatives. Procedures also have been developed for testing metabolic products of ingested compounds for teratogenicity. Mice and rats are fed the particular agent to be tested, and their serum is then added to the differentiating culture. Preliminary trials with human serum from patients receiving chemotherapy have also been performed. With further testing, validation, and incorporation of a metabolic activation system, it is hoped that this assay can be used, along with a battery of other in vitro assays, as a screen for the large number of agents awaiting comprehensive testing of their teratogenic potential. We also see the use of this assay as means to gain further information on the basic biochemical and developmental aspects of teratogenesis.

Animals↗
PubMed1982

Quantitative DNA determinations by image analysis. I. Application to human pulmonary cytology.

A description is made of the application of image analysis to quantitative deoxyribonucleic acid (DNA) determinations in a variety of cells. Optical density of the video signal from Feulgen-stained material was integrated across the area of the nucleus and values obtained related to values derived from known diploid cells. Analysis was performed on three classes of material: (1) biological material with known haploid, diploid and tetraploid nuclear DNA (standards), (2) metaplasias of the bronchial epithelium and (3) bronchogenic carcinomas. Results obtained with image analysis corresponded with expected data for the biologic standards and with microspectrophotometric data obtained for metaplasia and epidermoid carcinoma of the bronchial system. Application of this and other quantitative methods to cancer screening and biology is discussed.

Carcinoma, Bronchogenic↗
PubMed1981

A clinically relevant canine lung cancer model.

Research on early human lung cancer is difficult; we have sought a canine correlate. Regimens included endobronchial submucosal injections and topical focal applications of benzo[a]pyrene, nitrosomethylurea, dimethylbenzanthracene, and methylcholanthrene, singly or in combinations. Sustained-release discs were placed into lung parenchyma or sutured into major bronchi. Tracheal segments were isolated as cervical pedicle grafts. Gross and histological evolution was reproducible. Columnar and basal hyperplasia and squamous metaplasia were early changes. Atypia occurred within 6 weeks and was found in all dogs within 16 to 18 weeks. Invasive cancers occurred within 8 to 65 months. No tracheal graft developed cancer. Of 15 dogs with parenchymal sustained-release implants, 1 to date has developed cancer in 8 months. Four endobronchial regimens have produced 16 cancers in 56 lungs at risk for 18 to 65 months. No cancers developed in 23 lungs at risk from eight other regimens. Of 10 dogs at risk for unilateral endobronchial cancer, 5 have had cancer. Of 23 dogs with both lungs at risk, 9 developed cancer. We have shown focal carcinogenesis with well-defined pathogenesis and an extended preneoplastic period at predictable sites in a lung cancer model.

9,10-Dimethyl-1,2-benzanthracene↗