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Biomedical subjects

M Hess

Publications and source records attributed to M Hess.

At least 127 records · Page 7Linked to original sources
PubMed1995

Regulation of low density lipoprotein receptor gene expression in HepG2 and Caco2 cells by palmitate, oleate, and 25-hydroxycholesterol.

Our in vivo studies in mice have shown that LDL-receptor gene expression is regulated differently in both liver and intestine by dietary cholesterol and dietary saturated fat. While dietary cholesterol serves to regulate at transcriptional levels, dietary fatty acids do not. To study the mechanism of regulation of LDL-receptor by saturated fat and cholesterol at the cellular level, where any secondary effects of long-term feeding in vivo are minimized we used the cultured hepatoma and colon carcinoma cells, HepG2 and Caco2. LDL-receptor activity was determined by 125I-labeled LDL binding and uptake, LDL-receptor protein by Western blotting, LDL-receptor mRNA by RNase protection assay, and relative rates of LDL-receptor mRNA transcription by nuclear 'run-off' assay. Incubation of cells in lipoprotein-deficient serum (LPDS) for 48 h progressively induced LDL-receptor activity and LDL-receptor protein by 5- to 6-fold in HepG2 cells and 2- to 3-fold in Caco2 cells. Absolute levels of LDL-receptor mRNA and relative rates of LDL-receptor mRNA transcription also increased in parallel to the LDL-receptor activity and protein levels in both cell lines. These data suggest that LPDS induced the LDL-receptor gene by transcriptional mechanism. The suppressive effect of 25-hydroxycholesterol on LDL-receptor regulation was studied by incubating HepG2 and Caco2 cells grown either in 10% FCS or 10% LPDS for 24 h and then for 0-24 h with various doses of 25-hydroxycholesterol. In HepG2 cells, LDL-receptor activity and protein mass progressively decreased to 50% of zero time controls over 24 h. LDL-receptor mRNA levels and relative rates of transcription decreased in parallel. In Caco2 cells, 25-hydrocholesterol lowered LDL-receptor activity, mRNA, and transcription by approximately 35%. To examine the effects of palmitate on LDL-receptor regulation, palmitate was complexed with albumin. Palmitate decreased LDL-receptor activity by 25% in HepG2 cells without altering LDL-receptor mass, mRNA levels, or rates of mRNA transcription. Similarly, in Caco2 cells, palmitate decreased LDL-receptor activity and protein mass 30% of controls, but did not change LDL-receptor mRNA levels and/or rates of transcription. The combination of palmitate (0.8 mM) and 25-hydroxycholesterol (2.5-5 micrograms/ml) suppressed LDL-receptor activity by 65% in HepG2 cells and by 52% in Caco2 cells. However, LDL-receptor mRNA decreased by approximately 50% in HepG2 cells and 30-40% in Caco2 cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Blood↗
PubMed1995

Suppression of natural killer cell activity by serum derived from head and neck cancer patients.

Natural killer (NK) cells play an important role in many immune functions, including the lysis of tumor cells. In this study, we analyzed the influence of serum from 40 patients with head and neck cancer on NK cell activity using a double-layer agar assay. NK cell activity can be express as the inhibitory effect of NK cells on colony growth of K562 cells in the double-layer agar assay. When serum from cancer patients was added in this assay, we observed the reduction of the inhibitory activity of NK cells, not only of autologous NK cells but also of allogeneic NK cells in 24 out of 40 patients. In addition, we compared the TNM staging and survival rate between the reduction group and no-reduction group of NK cell activity. These results suggest that the serum of some patients with head and neck cancer may be an inhibitory factor on NK cell activity and may be involved in host resistance to tumor growth.

Adult↗
PubMed1994

The orienting response to brief auditory stimuli in preweanling and adult rats.

The cardiac orienting response to brief auditory stimuli was measured in preweanling and adult rats. The eliciting stimulus varied in duration (2 or 10 s) and complexity (continuous or pulsing). Stimulus complexity affected response magnitude with the pulsing stimulus eliciting a larger response than the continuous stimulus. Stimulus duration affected response persistence but only when a pulsing stimulus was used. In contrast to recent research with stimuli of much longer duration, age did not significantly affect any aspect of the cardiac response to the novel auditory stimuli in the present study. These results are discussed in terms of (1) the effects of stimulus duration on the heart-rate component of the orienting response and (2) two-stage models of attention.

Aging↗
PubMed1994

Value of serial myoglobin levels in the early diagnosis of patients admitted for acute myocardial infarction.

STUDY OBJECTIVE: The potential for missing the diagnosis of acute myocardial infarction (AMI) and the need for appropriate use of ICU beds make early and accurate diagnostic tests to assist in this diagnosis valuable. We studied the use of serial myoglobin determinations for patients evaluated in the emergency department and admitted for possible AMI. DESIGN: Over a 3.5-month period, all patients presenting to the ED and admitted for suspected cardiac symptoms had serial cardiac enzymes obtained prospectively at admission and 2, 3, 4, and 6 hours after the onset of symptoms. SETTING: Large urban community hospital. PARTICIPANTS: One hundred thirty-three consecutive patients admitted to treat or rule out AMI. RESULTS: Twenty-one of 22 patients with an initially normal myoglobin that doubled within 1 to 2 hours after presentation were positive for AMI (specificity, 95%). Sensitivity of myoglobin at 2 hours after the onset of symptoms was 37% and rose to 86% at 6 hours, with 95% specificity. The negative predictive value if myoglobin was normal at 6 hours and had not doubled within 2 hours was 97% (positive predictive value, 88%). CONCLUSION: A repeat myoglobin level that doubled within 1 to 2 hours after the initial value, even if still within the normal range, was highly specific for AMI. Serial myoglobin levels may be useful in earlier identification of AMI to help prevent inappropriate discharge from the ED and for appropriate placement in ICU beds.

Acute Disease↗
PubMed1994

[Secondary ambulatory voice prosthesis implantation with the argon laser using local anesthesia].

An alternative technique for secondary tracheo-esophageal puncture and voice prosthesis implantation in topical anesthesia on an outpatient basis was developed. With argon laser beam passed through a glass fibre in the instrument channel of a flexible endoscope a secondary puncture of the tracheo-esophageal wall is obtained. A voice prosthesis is fitted subsequently, so that the whole operation is performed in one session in about 30 minutes. We generally administer 7.5 mg Midazolam orally for light sedation; antibiotics are not required. This method expands the possibility of voice prosthesis fitting in patients who are not considered or willing to have general anesthesia for various reasons. In 33 cases we did not see any complication. In two cases the tracheal wall was too tight due to radiation therapy, so that an operation had to be performed later on in general anesthesia. In one case technical problems led to an operation in local anesthesia in two steps. In all cases the patients did not complain of any considerable discomfort.

Ambulatory Surgical Procedures↗
PubMed1994

The gallium scan predicts relapse in patients with Hodgkin's disease treated with combined modality therapy.

The gallium scan (GS) is an important indicator of disease activity in untreated Hodgkin's disease, especially in the upper torso, and may be an important predictor of results for patients who have completed chemotherapy and radiotherapy (XRT). To better define the importance of the GS in predicting treatment results in a group of patients treated with uniform therapy, we performed GS prior to treatment in 46 patients with pathologically or clinically staged I-III Hodgkin's disease who received three cycles of NOVP (Novantrone, vincristine, vinblastine, prednisone) followed by XRT. Staging methods included computerized tomography (CT) of the chest, abdomen, and pelvis, lymphangiogram, and the GS, using 8 to 10 millicuries with single photon emission computed tomography (SPECT) of the upper and lower torso. Only 3 patients had negative GS before chemotherapy. After three cycles of NOVP and prior to XRT, the other 43 had repeat GS performed. Complete remission (CR) was judged by disappearance of disease after all therapy without considering GS results. The CR for those with initial positive GS was 93%. The three-year freedom from progression result for stage I-II was 94%, and the three-year overall survival was 96%; corresponding results for stage III were 86% and 100%, respectively. None of the prognostic factors for analysis, including bulky adenopathy, hilar involvement, or B symptoms, was an important predictor of results. However, only 1 of the 33 with a negative GS after these NOVP has had progressive disease compared to 3 of the 10 with a GS that remained positive.(ABSTRACT TRUNCATED AT 250 WORDS)

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1994

[Pathogenicity of avian adenoviruses in chickens].

In the last years avian adenoviruses have caused diseases with similar symptoms and high losses in four countries. The causative viruses could be grouped by cross-neutralization tests and restriction enzyme analysis into four serotypes. Within the serotypes there exist strains with pathogenic properties as well as strains without pathogenicity. Epidemiologic investigations demonstrated that not only immunosuppression or co-infections produce diseases after adenovirus infections. Vertical transmission of the virus from parent stocks and deficiency of specific maternal antibodies in the chickens contribute to the development of diseases. Parent stocks, which were infected with different serotypes of adenovirus during their rearing period, produce chickens with maternal antibodies. These chickens are protected against early infections with avian adenoviruses.

Adenoviridae Infections↗
PubMed1994

Expression of interleukin-8 gene in inflammatory bowel disease is related to the histological grade of active inflammation.

Interleukin-8 (IL-8) is a potent cytokine for recruitment and activation of neutrophils. To visualize its distribution in the intestinal mucosa and to understand better its possible role in the induction and promotion of inflammatory bowel disease, expression of the IL-8 gene was analyzed in resected bowel segments of 14 patients with active Crohn's disease or ulcerative colitis. In situ hybridization with IL-8 anti-sense RNA probes revealed strong and specific signals in the histologically affected mucosa. The number of cells expressing IL-8 gene correlated with the histological grade of active inflammation. In accordance with the characteristic histological signs of active disease, IL-8-expressing cells were diffusely distributed over the entire affected mucosa in patients with ulcerative colitis, whereas in patients with Crohn's disease, IL-8-expressing cells showed a focal distribution pattern. Cells expressing IL-8 were mainly located at the base of ulcers, in inflammatory exudates on mucosal surfaces, in crypt abscesses, and at the border of fistulae. Analysis of semi-serial sections pointed to macrophages, neutrophils, and epithelial cells as possible sources of this cytokine in active inflammatory bowel disease. We consistently failed to detect IL-8 messenger RNA in the mucosa of uninvolved bowel segments and in normal-appearing control mucosa of patients with colon cancer. In contrast, tissue specimens from two patients with acute appendicitis displayed IL-8-expressing cells in the mucosa. These results support the notion that IL-8 plays and important but nonspecific role in the pathogenesis of inflammatory bowel disease and that the production of IL-8 messenger RNA is restricted to areas with histological signs of inflammatory activity and mucosal destruction.

Adult↗
PubMed1993

Morphologic analysis of three-dimensional tumors developed in fibrin matrix and agar culture system.

The three-dimensional growth of cultured tumor cell lines (HT29, a colon adenocarcinoma cell line; M21, a melanoma cell line; KB, a nasopharyngeal carcinoma cell line) has been investigated in an agar culture system with a fibrin matrix in vitro. The tumor cells developed to tumors 3 x 3 mm in diameter after 10 days in culture in vitro. This size was large enough to allow histologic examination. The tumor cells located in the surface area of the three-dimensional tumor seemed to grow well. However, the tumor cells in the center degenerated or did not proliferate, indicating a lack of nutrition and/or anoxia in the center. The histologic comparison between the xenografted tumors on nude mice and the three-dimensional tumors in vitro suggests that the structures of the three-dimensional tumors were comparable, especially in the surface area, to the xenografted tumors. Furthermore, the antitumor effect of mitomycin C on the three-dimensional tumors was found to be dose-dependent.

Adenocarcinoma↗
PubMed1993

[Individual adjustment of tracheal valves in voice prosthesis patients with morphologically aberrant stoma relations].

We present a new method of individual tracheal valve fitting for laryngectomized patients with voice prosthesis. In cases with morphologically poor tracheostoma the adhesion of the tracheal cannula or valve ring might be impaired by reduced contact surface to the skin. In some cases obligatory circumferential occlusion leads to stretching and higher tension of the adhering ring. Our technique of individual fitting with a silicon adapter permits airtight, tension-free adherence of tracheal valves, or, if desired, facilitation of stoma-closing with a finger, when the tracheostoma is deformed or too big.

Humans↗
PubMed1992

Recurrent abnormalities of chromosome bands 10q23-25 in non-Hodgkin's lymphoma.

Many nonrandom chromosome abnormalities have been associated with non-Hodgkin's lymphomas (NHL). Some of these are nonspecific changes seen in many different histologic subtypes. We describe a series of abnormalities of chromosome bands 10q23-25 seen in 159 consecutive NHL patients with abnormal cytogenetic findings. The proportion of karyotypes with abnormalities of 10q varied from 3% among the immunoblastic lymphomas to 67% in the diffuse large cleaved cell lymphomas. Seventeen (10.7%) had abnormalities of 10q23-25. All but one of these were B-cell tumors. The abnormalities consisted of six deletions and 11 translocations. Sixteen of the 17 patients had the 10q abnormality when cells were first karyotyped. The remaining patient acquired the 10q abnormality in the third of a series of biopsies. In the follicular histologic subtypes [follicular small cleaved cell (FSC), follicular mixed small cleaved and large cell (FM), and follicular large cell noncleaved (FL-NC)], abnormalities of 10q were found in nine patients, all in association with abnormalities of 14q32. Seven of these were associated with the t(14;18)(q32;q21). Overall, 10q23-25 abnormalities were observed in 11.9% (8/67) of low-grade [small lymphocytic (SL), FSC, and FM] lymphoma cases. DNA was available from five patients with abnormalities of 10q and was probed for rearrangements with the HOXII (TCL3) oncogene probe. As expected, we did not find such rearrangements in these five patients with B-cell tumors. Abnormalities of 10q23-25 have been reported previously in NHL but not at this frequency.

Blotting, Southern↗
PubMed1992

Secretion of salivary immunoglobulin A in relation to age, saliva flow, mood states, secretion of albumin, cortisol, and catecholamines in saliva.

Salivary immunoglobulin A (IgA) is one characteristic humoral factor of the local immune system in the upper respiratory tract. Epidemiological studies emphasize the importance of secretory IgA in the protection from infections of the upper respiratory tract. However, due to high interindividual variability of secretion of salivary IgA, it remains difficult to define normal ranges. This series of studies focused on identification of factors influencing basal secretion of salivary IgA. The results indicate a significant relationship between age and salivary IgA concentration. Children below 7 years have lower salivary IgA concentration than children above 7 years or adults. Furthermore, a significant inverse relationship between saliva flow and salivary IgA concentration was found. Gender, mood states, salivary albumin, salivary catecholamines, and salivary cortisol were not associated with salivary IgA. It can be concluded that for defining normal ranges of salivary IgA, age and saliva flow have to be considered.

Adolescent↗
PubMed1992

[Pericardial manifestations of toxoplasmosis].

A case of pericarditis due to toxoplasmosis in a 20 year old non-immune depressed man with a favourable outcome with specific antiparasitic treatment is reported. Pericarditis is rare in toxoplasmosis and does not require an associated immune deficiency. The clinical presentation is that of acute benign pericarditis, the diagnosis depending on positive toxoplasmosis serology (positive IgM or increasing IgG antibody titres) and the absence of another obvious cause. Isolation of the parasite by direct examination or animal inoculation is very rare. The spontaneous evolution is to pericardial constriction whilst specific antibiotic therapy (sulfadiazine-pyrimethamine) leads to a rapid cure in most cases. This underlines the necessity of searching for toxoplasmosis in patients with unexplained pericarditis.

Adult↗
PubMed1991

Cloning of hippocampal poly(A) RNA sequences that increase after entorhinal cortex lesion in adult rat.

Evidence is given for altered gene expression in the hippocampus in response to entorhinal cortex lesioning. Three RNA markers encoding glial fibrillary acidic protein, apolipoprotein E and alpha-tubulin were isolated from a rat hippocampal cDNA library by differential screening with cDNA probes from entorhinal cortex lesioned and control rat hippocampus RNA. By Northern blot analysis, mRNA for apolipoprotein E and alpha-tubulin increased to peak around 6 days after the lesion and returned to near control level at 30 days. The increased synthesis of both mRNAs coincides with the acute phase of synaptogenesis, protein synthesis, and polyribosomes accumulation in the deafferented hippocampal area.

Animals↗
PubMed1991

Astrocytic apolipoprotein E mRNA and GFAP mRNA in hippocampus after entorhinal cortex lesioning.

Entorhinal cortex lesions (ECL) that damage the perforant path to the hippocampus induce rapid increases of apolipoprotein E (apo E) mRNA in the hippocampus. Apo E mRNA was localized in astrocytes by in situ hybridization in combination with immunocytochemistry for glial fibrillary acidic protein (GFAP). Unilateral ECL also increased hippocampal GFAP mRNA, with increases preceding those of apo E mRNA. The apo E mRNA and GFAP mRNA responses were transiently bilateral in non-denervated zones. The timing of response in apo E mRNA to deafferentation supports suggestions that apo E has roles in membrane remodelling during responses to neuron injury.

Animals↗