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Biomedical subjects

M Strauss

Publications and source records attributed to M Strauss.

At least 145 records · Page 8Linked to original sources
PubMed1994

BCL-1/cyclin D1 oncoprotein oscillates and subverts the G1 phase control in B-cell neoplasms carrying the t(11;14) translocation.

In an effort to elucidate the biological role played by cyclin D1, a candidate BCL-1 oncogene, in human B-cell tumours carrying the t(11;14) translocation, we have studied the properties of this cyclin protein in a series of human lymphoid lines with rearrangements in the BCL-1 locus. The BCL-1/cyclin D1 protein was easily detectable in both immunocytochemistry and immunoblotting, its abundance grossly correlating with the mRNA levels. The cyclin D1 protein was localised predominantly to nuclei and there was a striking variation of staining intensity among the exponentially growing cells, reflecting the maximum level reached in mid/late G1 and the lowest level in S-phase. This characteristic mode of cell cycle-dependent oscillation was confirmed by three independent approaches, demonstrating that even upon rearrangement, the expression of cyclin D1 is regulated in a cyclical manner. Antibody-mediated and anti-sense oligonucleotide 'knockout' experiments revealed that the aberrantly expressed BCL-1/cyclin D1 protein is required for G1 phase progression of all four B-cell tumours with the BCL-1 rearrangement. Consistent with the proposed oncogenic role of this cyclin, our data demonstrate that the BCL-1 deregulation caused by chromosomal rearrangement leads to expression of a functionally active cyclin D1 protein which subverts the G1 phase control in the human B-cell tumours carrying the t(11;14) translocation.

Base Sequence↗
PubMed1994

Head and neck cancer in blacks.

Our experience at University Hospitals of Cleveland (UHOC), Cuyahoga County, Ohio, led us to suspect an increased incidence of head and neck cancer in blacks. We reviewed our tumor registry records from 1975 to 1989 analyzing for age, sex, race, and head and neck site of disease. Head and neck cancers comprised 6.1% of all cancers at UHOC. This is in comparison with 3.7% of all cancers in Cuyahoga County and an estimated 5.5% nationally. This higher proportion of head and neck cancer was observed primarily in black men and women in whom these cancers made up 7.7% of all cancers compared with 5.7% in whites. Both black men and women had a higher percentage of these cancers out of all cancers for their respective sex and race than whites. For all head and neck cancer sites except the salivary glands, blacks were observed to be two to four times more likely than whites to be diagnosed before the age of 50 years (P < .01). These findings thus substantiated an increased incidence and earlier age of onset of head and neck cancers in blacks compared with whites.

Adult↗
PubMed1993

A mutant T7 phage promoter is specifically transcribed by T7-RNA polymerase in mammalian cells.

The phage T7 promoter/polymerase system is highly specific in bacteria in contrast to that observed in mammalian cells. A number of cell lines exhibit a considerable level of expression from the T7 promoter, even in the absence of T7-RNA polymerase. Here, we demonstrate that nuclear-factor-including components of the TFIID fraction, bind to the T7 promoter and inhibit transcription by T7-RNA polymerase. In order to increase the specificity of the promoter for T7-RNA polymerase and to abolish binding of nuclear factors, a novel strategy for the selection of randomly mutated promoters was established. The strategy involves adsorption of mutant promoters to HeLa extracts and binding of the free oligonucleotides to T7-RNA polymerase, cloning, and functional testing of the recombinants. After selection, the resulting mutant promoters showed an increase in specificity for transcription by T7-RNA polymerase.

Animals↗
PubMed1993

A phage T7 class-III promoter functions as a polymerase II promoter in mammalian cells.

A phage T7 class-III promoter (pT7), which is highly specific for T7 RNA polymerase in bacteria, was tested in mammalian cells for its specificity. After having shown that T7 RNA polymerase can transcribe from pT7 in the nucleus of stably transformed cells [Lieber et al., Nucleic Acids Res. 17 (1989) 8485-8493], we describe here that pT7 could also direct efficient intracellular gene expression in the absence of T7 RNA polymerase. Using the genomic human growth hormone-encoding gene and the firefly luciferase-encoding gene as reporters, we found expression levels comparable with those obtained with the Rous sarcoma viral promoter. Inhibition of expression with alpha-amanitin suggests that transcription is by RNA polymerase II. Binding studies with HeLa cell extracts clearly show that synthetic pT7 sequences are specifically bound (gel retardation) and that the promoter region is protected from DNase degradation. The experimental data, as well as the nucleotide sequence, suggest that pT7 has properties of an initiator element. Indeed, the activity of pT7 can be stimulated by the presence of an upstream element or an enhancer. These results have practical implications for the use of pT7 in mammalian expression vectors. Commercial pT7 plasmids can be used for both prokaryotic and eukaryotic expression systems.

Animals↗
PubMed1993

Identification of differentially expressed mRNA species by an improved display technique (DDRT-PCR).

We have significantly improved a method originally developed by Liang and Pardee [Science 257 (1992) 967-971] to display a broad spectrum of expressed genes and to detect differences in expression between different cell types. We have analysed various aspects of the technique and have modified it for both, the application to fast and efficient identification of genes and the use with automatic analysis systems. Based on the mathematical background we have devised the appropriate number of optimal PCR primers. We have also introduced nondenaturating gels for separating double stranded fragments as single bands. By applying the method to regenerating mouse liver, we have identified, out of a total of 38,000 bands, about 70 fragments where the expression of the corresponding genes seems to be differentially regulated at different time points. Application of the method to an automatic DNA sequencer was successfully done. Thus, we have confirmed the usefulness and increased the power of the RNA display technique, which we named differential display reverse transcription PCR (DDRT-PCR), and have extended the range of its application.

Animals↗
PubMed1993

Expression cloning of the early activation antigen CD69, a type II integral membrane protein with a C-type lectin domain.

CD69 is a very early activation Ag of T lymphocytes. It is a cell surface glycoprotein that can only be detected after stimulation of lymphocytes. Despite extensive studies on its biologic activities, little is known about its molecular function. To investigate the latter in more detail, we have cloned a cDNA encoding CD69 on the basis of its expression in COS cells. The nucleotide sequence of clone CD69.13 is 1676 bp in length and contains a single open reading frame of 600 bp encoding a protein of 199 amino acids. The predicted molecular mass of 22,559 Da could be confirmed by in vitro translation. The protein contains a hydrophobic transmembrane region between amino acids 41 and 61 but no N-terminal signal peptide, which suggests that it is a type II membrane protein. It has one potential N-glycosylation site at amino acid 166. Two glycosylated forms of 26 to 28 kDa and 32 to 34 kDa were detected both in transfected COS cells and in in vitro translation in the presence of canine microsomes. Proteinase K degradation of the N-terminal part after in vitro protein synthesis supports the view of CD69 being a type II integral membrane protein with the N-terminal 40 amino acids in the cytoplasm, a transmembrane domain of 21 amino acids, and C-terminal 138 amino acids as the extracellular domain. Homology searches revealed sequence similarity with members of a supergene family of type II integral membrane proteins with a C-type lectin domain, indicating that CD69 is involved in signal transduction.

Amino Acid Sequence↗
PubMed1993

Surgical treatment of obstructive sleep apnea. Technical variations.

OBJECTIVE: To determine the effectiveness of the two basic surgical types of uvulopalatopharyngoplasty (UPPP), as classified by us. The two basic surgical variations of UPPP differ for the width of the anteroposterior palatal resection, being 1 to 2 cm (type 1) and 0.5 to 1.0 cm (type 2). DESIGN: Randomized, retrospective study. PATIENTS: Eighty-seven patients with obstructive sleep apnea hospitalized in our department from 1983 to 1991. All patients had a complete preoperative and postoperative polysomnographic evaluation. RESULTS: The operation was found to be an effective treatment of obstructive sleep apnea in most patients. Snoring improvement was found in 95% (29/31) of patients with type 1 UPPP and in 96% (54/56) of the patients with type 2 UPPP, whereas, apnea index improvement was detected in 65% (20/31) of the patients with type 1 UPPP vs 64% (36/56) of the patients with type 2 UPPP. Postoperative dysphagia was found in 94% (29/31) vs 79% (44/56), P = .0025; nasal reflux was found in 81% (25/31) vs 11% (6/56), P = .0001; and hypernasality was found in 100% (31/31) vs 13% (7/56), P = .0001, in type 1 and type 2 UPPP operations, respectively. Chi-square analysis shows highly significant differences. CONCLUSIONS: Type 2 UPPP is the recommended surgical procedure of obstructive sleep apnea, mainly due to the minimal postoperative morbidity.

Deglutition Disorders↗
PubMed1993

Regional sublocalization of the human CD69 gene to chromosome bands 12p12.3-p13.2, the predicted region of the human natural killer cell gene complex.

The early activation antigen CD69 is a member of a supergene family of type II integral membrane proteins with a C-type lectin domain. In recent reports the genes encoding the natural killer (NK) cell-related molecules of this supergene family, NKR-P1, NK1.1 and Ly-49, were shown to be clustered in a chromosomal region in mouse, termed the NK gene complex. The human homologue of this complex is likely to reside on chromosome 12 near the PRP locus (12p13.2). By analyzing T cell hybrids, the CD69 gene was previously mapped to human chromosome 12. Here we report the regional sublocalization of the human CD69 gene to chromosome bands 12p12.3-p13.2, suggesting that CD69 belongs to one linkage group together with different cell surface molecules on NK cells.

Animals↗
PubMed1993

Dopamine D2 receptor density estimates in schizophrenia: a positron emission tomography study with 11C-N-methylspiperone.

Positron emission tomography (PET) with 11C-N-methylspiperone as the radioligand was carried out in 25 chronic schizophrenic patients to determine dopamine D2 receptor density estimates in the corpus striatum. The sample included 18 neuroleptic-naive and 7 neuroleptic-free patients. Dopamine D2 receptor density estimates (Bmax) were obtained using a two-scan/four-compartment model. The Bmax estimates for the entire group (33.39 +/- 3.43 pmole/g) were significantly elevated when compared with estimates for the control group (Bmax = 15.63 +/- 2.38). The Bmax values for the entire group of schizophrenic patients showed a significant decline as a function of age. The Bmax values were significantly related to duration of illness (y = 13.2 + 10.3795x - 0.7931x2; r = 0.48). Thirteen patients and seven control subjects were added to our original publication sample (Wong et al., 1986c). The patients' Bmax values, when adjusted for age and sex effects, were significantly different compared with those of control subjects. Clinical data from the entire group were compared with published data from other research groups that have estimated dopamine D2 receptor density using different radioligands and different methods of data analysis. Comparisons of the clinical characteristics of the published studies show significant differences in patient populations, suggesting that discrepancies among published studies may reflect, in part, heterogeneity among groups of schizophrenic patients. The D2 receptor abnormality described in this study may be a late manifestation of disease, and the implications of this observation are discussed.

Adult↗
PubMed1993

The impact of therapy with filgrastim (recombinant granulocyte colony-stimulating factor) on the health care costs associated with cancer chemotherapy.

The objective of the study was to estimate the net impact on health resource utilisation of using recombinant granulocyte colony-stimulating factor (filgrastim) following myelosuppressive chemotherapy. Cost minimisation of the study medication in a randomised, double-blind, placebo-controlled clinical trial was conducted in teaching institutions and affiliated community hospitals participating in a clinical trial. 68 patients with small cell lung cancer undergoing cyclophosphamide, doxorubicin and etoposide chemotherapy were randomised to blinded placebo or filgrastim study medication at three or 14 clinical trials sites. The patients received daily subcutaneous injections of filgrastim or placebo, initiated 24 h after chemotherapy and continued until the neutrophil count exceeded 10,000 x 10(6)/l after the time of the expected nadir. Differences in total charges, costs and Medicare payments between treatment groups were the main outcomes measured. Compared to placebo patients, filgrastim-treated patients had significantly fewer and less resource-intensive hospitalisations. After accounting for filgrastim purchase and administration, the charge model predicts overall savings from filgrastim use in a clinical setting in which the risk of febrile neutropenia is high for patients not receiving filgrastim. The Medicare and cost models predict only a partial recapture of the cost of filgrastim therapy. The health care resources impact of filgrastim was sensitive to the risk of hospitalisation with febrile neutropenia, and to the perspective chosen for measuring resource utilisation (charges, costs or Medicare payments). The adjunctive use of filgrastim following myelosuppressive chemotherapy leads to partial or complete recapture of the cost of purchasing and administering the product.

Analysis of Variance↗
PubMed1993

Leishmania braziliensis promastigotes and amastigotes interact differently with host macrophages.

In vitro and in vivo ultrastructral studies reveal that the parasite entrance into the macrophage occurs by phagocytosis. The early stage of phagocytosis exhibited different ultrastructural characteristics in both forms of the parasite. Long and prominent projections from peritoneal exudate macrophages made focal contacts with the promastigote surface. The amastigotes, in turn, laid on cup-shaped extensions of the macrophage membrane. Later stages of the phagocytosis are characterized by progressive and complete engulfment of both promastigotes and amastigotes.

Animals↗
PubMed1992

Airway and other complications of percutaneous endoscopic gastrostomy in head and neck cancer patients.

The purpose of this study was to look at complications associated with percutaneous endoscopic gastrostomy (PEG) in a group of head and neck cancer patients. We retrospectively reviewed charts of 46 patients referred for PEG. Three of 29 patients without secured airways (10.3%) had acute airway obstruction after administration of sedation for the PEG procedure. Two required emergency tracheostomy. Three additional patients of these 29 (10.3%) presented within 2 months of their PEG attempts with tumor-related airway obstruction requiring emergency tracheostomy. There were no other serious complications noted in our review. We concluded that our group of head and neck cancer patients were at high risk for airway obstruction, especially when sedated, and that the acute risk was not directly associated with the PEG procedure. We also concluded that referral for PEG should be made in anticipation of future nutritional needs and that PEG should not be used only as a late-stage procedure.

Airway Obstruction↗
PubMed1992

Stimulation of cell division and fibroblast focus formation by antisense repression of retinoblastoma protein synthesis.

Circumstantial evidence supports a role for the retinoblastoma susceptibility gene, Rb-1, in the maintenance of normal cell growth, in that loss of its function results in abnormal growth and malignancy. Here we report that a high rate of mitosis and efficient dense focus formation in human embryonic lung fibroblasts (HEL cells) is induced by antisense oligonucleotide-directed inhibition of synthesis of p105-Rb, the product of the Rb-1 gene. mRNA specific for p105-Rb is truncated at the site of base pairing with the antisense oligonucleotide, and no synthesis of p105-Rb is observed. The rate of mitosis is considerably increased and the frequency of dense focus formation is extremely high in treated cells. However, although phosphothioate oligodeoxyribonucleotides taken up by the cells remain stable for at least 4 weeks, the recipient cells do not become immortal; nor are they able to induce tumor formation in nude mice. Thus, loss of Rb-1 function is not sufficient per se to allow malignant transformation.

Base Sequence↗
PubMed1991

Functional significance of sequences following the TATA box of an immunoglobulin promoter studied by random mutagenesis.

We have investigated the importance of sequences downstream to the TATA box of an immunoglobulin promoter by transfection and in vitro transcription assays. A sequence from -11 to +10 with respect to the transcriptional start site was synthesised by a procedure allowing for random misincorporation of nucleotides. The pool of mutant oligonucleotides was cloned into the respective position of a vector carrying a fusion of a synthetic immunoglobulin heavy chain promoter with the human growth hormone gene. From 200 clones sequenced, 115 were mutants with at least one nucleotide exchange in every position. Whereas most mutations are of minor functional importance, changes at or near the transcriptional start site reduce the promoter activity considerably.

Base Sequence↗