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Biomedical subjects

M A Cohn

Publications and source records attributed to M A Cohn.

At least 19 recordsLinked to original sources
PubMed2002

Possible co-regulation of genes associated with enhanced progression of mammary adenocarcinomas.

Tumor progression is a multistep process in which alterations in the expression of numerous gene products may give rise to highly malignant cellular variants. In the present study, we analyzed the differential expression of several genes in cellular variants of mammary adenocarcinomas with high or low malignancy potential, which originated in a common ancestor. To assess the generality of our findings, high and low malignancy variants were derived from two different mammary adenocarcinoma cell lines, namely DA3 and CSML cells. Of major importance is the fact that the differences between high- and low-malignancy variants observed in one system of mammary adenocarcinoma cells (DA3 cells) were identically reproduced in the other system of mammary adenocarcinoma cells (CSML cells). The high malignancy variants of tumors both DA3-high and CSML-high (previously called CSML-100), expressed higher levels of factors that induce monocyte migration than the low malignancy DA3-low and CSML-low (previously called CSML-0) variants. In addition, it was found that DA3-high and CSML-high cell variants expressed higher levels of monocyte chemoattractant protein-1 (MCP-1), interleukin-6 (IL-6) and matrix metalloproteinases (MMPs) than the low malignancy variants (DA3-low and CSML-low). These results suggest that MCP-1, IL-6 and MMPs potentially contribute to mammary adenocarcinoma progression and that their expression is regulated by a common pathway. The expression of MCP-1, IL-6 and MMPs in both DA3-high and CSML-high cells was up-regulated by tumor necrosis factor alpha (TNFalpha). The fact that TNFalpha exerted similar effects on the expression of these three factors in both cell systems raises the possibility of a coordinated co-regulation of tumor-promoting factors.

Adenocarcinoma↗
PubMed2001

Characterization of Sp1, AP-1, CBF and KRC binding sites and minisatellite DNA as functional elements of the metastasis-associated mts1/S100A4 gene intronic enhancer.

The mts1/S100A4 gene encodes a small acidic calcium-binding protein that is expressed in a cell-specific manner in development, tumorigenesis and certain tissues of adult mice. A composite enhancer that is active in murine mammary adenocarcinoma cells was previously identified in the first intron of the mts1/S100A4 gene. Here we present a detailed analysis of the structure and function of this enhancer in the Mts1/S100A4-expressing CSML100 and non-expressing CSML0 mouse adenocarcinoma cell lines. In CSML100 cells the enhancer activity is composed of at least six cis-elements interacting with Sp1 and AP-1 family members and CBF/AML/PEBP2 and KRC transcription factors. In addition, a minisatellite-like DNA sequence significantly contributes to the enhancer activity via interaction with abundant proteins, which likely have been described previously under the name minisatellite-binding proteins. Extensive mutational analysis of the mts1/S100A4 enhancer revealed a cooperative function of KRC and the factors binding minisatellite DNA. This is the first example of an enhancer where two nuclear factors earlier implicated in different recombination processes cooperate to activate transcription. In Mts1/S100A4-negative CSML0 cells the strength of the enhancer was 7- to 12.5-fold lower compared to that in CSML100 cells, when referred to the activities of three viral promoters. In CSML0 cells the enhancer could be activated by exogenous AP-1 and CBF transcription factors.

Allosteric Site↗
PubMed2001

Chronic inflammation with increased human immunodeficiency virus (HIV) RNA expression in the vaginal epithelium of HIV-infected Thai women.

Thai residents have a greater risk of heterosexual transmission of human immunodeficiency virus (HIV) than do US residents. To analyze host factors associated with heterosexual transmission, vaginal epithelial biopsies from HIV-seropositive Thai and US women were evaluated for tissue virus load and histologic makeup. In all, 84% of Thai and 14% of US women exhibited a chronic inflammatory T cell infiltrate in the vaginal epithelium. In Thai tissue, the infiltrate was associated with elevated levels of HIV RNA in the epidermis. Uninfected Thai women also had vaginal epithelial inflammation. Inflammation did not correlate with sexually transmitted diseases or HIV disease stage. The higher rates and increased risk of heterosexual transmission in Thailand may be due to chronic inflammation at the site where the virus is transmitted, which leads to the accumulation of activated T cells. Such cells might act as targets for initial viral infection and subsequently as reservoirs that support efficient transmission.

Adult↗
PubMed2000

The kappaB and V(D)J recombination signal sequence binding protein KRC regulates transcription of the mouse metastasis-associated gene S100A4/mts1.

A kappaB-like sequence, Sb, is integral to the composite enhancer located in the first intron of the metastasis-associated gene, S100A4/mts1. Oligonucleotides containing this sequence form three specific complexes with nuclear proteins prepared from S100A4/mts1-expressing CSML100 adenocarcinoma cells. Protein studies show the Sb-interacting complexes include NF-kappaB/Rel proteins, p50.p50 and p50.p65 dimers. Additionally, the Sb sequence was bound by an unrelated approximately 200-kDa protein, p200. Site-directed mutagenesis in conjunction with transient transfections indicate that p200, but not the NF-kappaB/Rel proteins, transactivates S100A4/mts1. To identify candidate genes for p200, double-stranded DNA probes containing multiple copies of Sb were used to screen a randomly primed lambdagt11 cDNA expression library made from CSML100 poly(A)(+) RNA. Two clones corresponding to the DNA-binding proteins KRC and Alf1 were identified. KRC encodes a large zinc finger protein that binds to the kappaB motif and to the signal sequences of V(D)J recombination. In vitro DNA binding assays using bacterially expressed KRC fusion proteins, demonstrate specific binding of KRC to the Sb sequence. In addition, introduction of KRC expression vectors into mammalian cells induces expression of S100A4/mts1 and reporter genes driven by S100A4/mts1 gene regulatory sequences. These data indicate that KRC positively regulates transcription of S100A4/mts1.

3T3 Cells↗
PubMed1998

Dendritic cells express multiple chemokine receptors used as coreceptors for HIV entry.

Cells of the dendritic lineage are thought to be among the first cells infected after mucosal exposure to HIV. In this study, we have identified the presence of multiple chemokine receptors on dendritic cells (DC) that may function as coreceptors for HIV entry. DC effectively used CCR5 for entry of macrophage (M)-tropic isolates. CCR3, the eotaxin receptor, initially identified on eosinophils, is expressed on DC and may be used as an entry coreceptor by certain dual-tropic strains. CXCR4 was not expressed on DC, although SDF-1 induced a calcium flux and DC could be infected by T cell line (T)-tropic HIV. Our findings provide evidence for the presence of a non-CXCR4 SDF-1 receptor on DC that is used mainly by T-tropic strains of HIV. DC from individuals homozygous for a 32-bp deletion of the CCR5 gene are also infectable with M-tropic strains of HIV-1, and this infection is inhibited by stromal cell-derived factor (SDF)1, suggesting that this receptor can also be used by M-tropic HIV for entry. Delineation of the spectrum of coreceptor usage on DC may offer new approaches to interfere with the initiation and propagation of HIV infection.

Base Sequence↗
PubMed1997

The differentiation antigen Ly-6E.1 is expressed in mouse metastatic tumor cell lines.

We report the cloning of the mouse surface GPI-anchored Ly-6E.1 protein from a highly metastatic mouse adenocarcinoma cell line CSML-100 by differential display. The expression is specific for the metastatic cell line as the closely related, non-metastatic mouse adenocarcinoma cell line CSML-0 does not express Ly-6E.1. Northern blot analysis reveals expression in a number of mouse tumour cell lines, exclusively metastatic ones. To date, active Ly-6A/E has only been described in lymphoid cells. The correlation between Ly-6E.1 expression, and the ability to metastasize, is discussed.

Adenocarcinoma↗
PubMed1993

Effects of zolpidem, codeine phosphate and placebo on respiration. A double-blind, crossover study in volunteers.

The effects of zolpidem, codeine phosphate and placebo on respiration were evaluated in a double-blind, randomised, crossover study involving 12 healthy men. Single oral doses of zolpidem 10 or 20 mg, codeine phosphate 60 mg or placebo were administered in the morning. Each treatment was separated by a washout period of at least 72 h. Ventilatory responses to carbon dioxide and mouth occlusion pressure, measured 1 h before and at 1 and 3 h after doses, were not significantly affected by either zolpidem dose; however, codeine phosphate produced a small but significant respiratory suppressant effect at 3 h. Mean inspiratory flow was noninvasively assessed using respiratory inductive plethysmography 1 h predose and at 1 to 5 h postdose. No significant change in mean inspiratory flow was noted after zolpidem 10 mg. Two hours after administration of zolpidem 20 mg, mean inspiratory flow was significantly lower than after placebo, possibly related to some individuals falling asleep during data collection. All volunteers reported adverse events; the most common were slurred speech (in 1 after 10 mg and in 5 after 20 mg of zolpidem), dizziness (in 4 after both 10 mg and 20 mg of zolpidem) and diplopia/blurred vision (in 4 after 20 mg of zolpidem). Zolpidem appears to be well tolerated, with no respiratory suppression up to doses of 10 mg and minimal suppression of mean inspiratory drive at doses of 20 mg.

Adult↗
PubMed1991

A comparison of nine nasal continuous positive airway pressure machines in maintaining mask pressure during simulated inspiration.

Nasal continuous positive airway pressure (CPAP) "splints" the airway and prevents inspiratory collapse of the upper airway in patients with obstructive sleep apnea. Nine nasal CPAP machines were compared for their ability to maintain airway pressure at various simulated inspiratory flows. Each machine was connected to a vacuum system at 20, 40, and 60 L/min flow after it was initially set at test pressures of 5, 10, or 15 cm H2O and the system or "mask" pressures were measured. In all machines, mask pressure fell during simulated inspiration and the declines in mask pressure were as high as 5 cm H2O. Because machines varied in their ability to maintain a test pressure, it is recommended that the nasal CPAP machine used in the home be the same as that which was tested in the sleep laboratory. If a different machine is used, it may require adjustment to assure efficacy.

Air Pressure↗
PubMed1990

Sleep disturbances in HIV-infected homosexual men.

To provide a better understanding of the etiology of subjective sleep complaints in HIV-infected individuals, a study to evaluate sleep/wake disturbances in 10 healthy HIV-infected male volunteers was performed. All subjects were HIV-infected but had no history of AIDS-related infections, and considered clinically asymptomatic. Interviews and sleep questionnaires revealed sleep complaints in nine subjects. Five healthy HIV-seronegative male subjects, with no history of sleep complaints, were also evaluated. Sleep architecture analyses detected that, in comparison to published normative data and to negative controls, there was a significant increase in the total percentage of slow wave sleep (SWS) and an increase in the percentage of SWS in the later sleep cycles. When compared with normative data, an increase in stage 1 shifts, rapid eye movement (REM) periods, and arousals were also observed in the HIV-infected group. Significant decreases in sleep latency, total percentage stage 2 sleep, and average REM durations were also observed in the HIV-infected group compared with normative data. These sleep architecture abnormalities could not be attributed to known sole primary sleep disorders, first night effect, medications, anxiety or depression. This study indicates that sleep disturbances occur early in the course of HIV infection and suggests that the observed alterations of sleep physiology may be a consequence of central nervous system involvement and/or immune defense mobilization in the early phases of HIV infection.

Adult↗
PubMed1990

The development of a sleep disorders laboratory.

The otolaryngologist is often asked to participate in the evaluation for possible surgical intervention in patients with sleep-related breathing disorders. The information from polysomnography performed in a sleep laboratory is often helpful in choosing among different treatment options. The relationship of the otolaryngologist to the sleep laboratory can range from medical director with overall responsibility for operation of the facility to referring physician with only a superficial involvement and is determined by complex local factors unique to the physician and the community he serves.

Accreditation↗
PubMed1988

Sleep apnea and the Chiari I malformation: case report.

The authors report the case of an ambulatory patient who presented with sleep apnea episodes of the central and obstructive types and an associated Chiari Type I malformation. The central episodes stopped and the obstructive episodes decreased markedly after decompression. The improvement in the so-called obstructive episodes was unexpected and indicates that they may have been on a central basis.

Adult↗
PubMed1984

The effects of brotizolam, a new hypnotic, on cardiac and respiratory function in volunteers.

In a double-blind, cross-over study we measured the effect of a 0.5-mg oral dose of brotizolam, a new thienodiazepine hypnotic, on cardiac and respiratory functions in 12 healthy volunteers. No deleterious effects on pulse, blood pressure, forced vital capacity, forced expiratory volume in 1 s, respiratory rate, mouth occlusion pressure (P0.1) and ventilatory responses to carbon dioxide occurred over a 6-hour period. In the usual therapeutic dose, brotizolam does not suppress cardiac and respiratory functions in healthy volunteers.

Adult↗