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Biomedical subjects

K Hess

Publications and source records attributed to K Hess.

At least 55 records · Page 3Linked to original sources
PubMed1997

Screening for colorectal cancer. A comparison of 3 fecal occult blood tests.

BACKGROUND: Colorectal cancer is the second leading cause of cancer deaths in the United States. Fecal occult blood testing has become a standard screening test for large-bowel cancers in the average asymptomatic population. Performance characteristics of the test and physician and participant compliance are the 2 major elements that impact the success of screening and early detection. OBJECTIVES: To evaluate the nonhydrated Hemoccult, rehydrated Hemoccult, and Hemoccult SENSA tests (SmithKline Diagnostics Inc, Palo Alto, Calif) and to assess participant and physician compliance. METHODS: A mass community-based screening study in an urban setting. Kits were distributed by a local pharmacy and at community sites. Diagnostic tests were completed through physicians' offices and clinics. Participants were asymptomatic and aged 50 years or older. Those who tested positive were advised to follow up with a physician. RESULTS: An overall positivity rate of 16% was reported for the 8293 kits that were processed. Rehydrated Hemoccult had a positivity rate of 15%; Hemoccult SENSA, 7%; and nonhydrated Hemoccult, 5%. The positive predictive value of nonhydrated Hemoccult was 14%; rehydrated Hemoccult, 7%; and Hemoccult SENSA, 11%. Of those who tested positive, 59% had a colonoscopy or flexible sigmoidoscopy and double-contrast barium enema examination on follow-up. Recommended follow-up was more frequent for those who consulted a gastroenterologist. CONCLUSIONS: Rehydrated Hemoccult yielded a higher positivity rate and lower positive predictive value than either Hemoccult SENSA or nonhydrated Hemoccult. Hemoccult SENSA approached the positive predictive value of nonhydrated Hemoccult. Adequacy of follow-up of patients testing positive for fecal occult blood needs improvement.

Aged↗
PubMed1997

Effect of boric acid solution on cartilage metabolism.

Pelvic cartilage of chick embryo was used to demonstrate that presence of boron in culture medium decreases synthesis of proteoglycans, collagen and total proteins but on the other hand increases the release of these macromolecules. However, when glucose concentration in culture medium is brought to 22mM, the synthesis decrease is no longer observed, whereas release increase persists. Proteins released into the culture medium included heat shock proteins (70 hsp) and tumor necrosis factor alpha (TNF alpha). The amount of phosphorylated proteins was enhanced in presence of boron while endoprotease activity in cartilage and in culture medium was significantly augmented. The in vitro effects of boric acid may explain its in vivo effect on wound healing.

Animals↗
PubMed1997

TPDC-FuHu chemotherapy for the treatment of recurrent metastatic brain tumors.

PURPOSE: To evaluate a combination of thioguanine, procarbazine, dibromodulcitol, CCNU (CCNU), fluorouracil, and hydroxyurea (TPDC-FuHu), designed to improve the efficacy of CCNU, in the treatment of recurrent metastatic brain tumors. PATIENTS AND METHODS: One hundred fifteen patients with progressive or recurrent metastatic brain tumors that failed to respond to surgery and/or radiation therapy were enrolled onto a multicenter prospective study between 1989 and 1995. Patients received TPDC-FuHu in a repeated cycle every 6 weeks until recurrence or until they completed six courses. RESULTS: Ninety-seven patients were assessable at the end of the study. Forty-eight had lung cancer (39 non-small-cell [NSCLC] and nine small-cell [SCLC]), 28 had breast cancer, nine had melanoma, and 12 had adenocarcinoma of different origins (three colon, two kidney, one bladder, one stomach, and five of unknown origin). The response and stable disease (SD) rate (overall response rate) was 52%, 66%, 60%, and 22% in patients with NSCLC, SCLC, breast cancer, and melanoma, respectively. Median time to progression (MTP) was 12, 26, 12, and 6 weeks, respectively, for the four groups. Side effects were mild to moderate in the majority of patients. Severe myelosuppression (grade 4) occurred in only 11% of the patients. CONCLUSION: TPDC-FuHu chemotherapy is an active treatment against recurrent brain metastases from breast cancer and SCLC, and to a lesser extent from NSCLC. This regimen is well tolerated and has acceptable toxicity.

Adenocarcinoma↗
PubMed1997

Renal and blood pressure effects of moxonidine and clonidine in spontaneously hypertensive rats.

Recently we could demonstrate that the imidazoline receptor agonist moxonidine exerts specific renal effects in Sprague Dawley rats [Hohage et al. 1997]. Interestingly, the effects of this compound are attenuated in one kidney-one clip hypertensive rats [Li et al. 1994]. In this study, we therefore investigated the effects of moxonidine as compared to clonidine in genetically determined spontaneously hypertensive rats. Moxonidine in a concentration of 0.5 mg/kg b.w.i.v. induced a significant and long-lasting increase of both urine flow from 11.9 +/- 2.1 microliters/min x 100 g b.w. to 50.3 +/- 12.5 microliters/min x 100 g b.w. and of Na(+)-excretion from 2.2 +/- 0.5 mumol/min x 100 g b.w. to 8.4 +/- 1.9 mumol/min x 100 g b.w. In contrast to moxonidine, the effects of clonidine (0.5 mg/kg b.w.i.v.) on urine flow and Na(+)-excretion were negligible. The antagonists idazoxan, effaroxan and rauwolscine abolished the effects of moxonidine on urine flow and Na(+)-excretion, whereas 4-aminopyridine, phenformine and 1,2,3,4-tetrahydro-9-aminoacridine, which have been described to interact with imidazoline binding sites, had no effect. Addition of the antagonists idazoxan, effaroxan and rauwolscine attenuated the initial blood pressure increase immediately after intravenous application, whereas 4-aminopyridine, phenformine and 1,2,3,4-tetrahydro-9-aminoacridine had no influence on this side-effect. Our results provide further evidence that imidazoline receptor agonists such as moxonidine exhibit renal effects, different from the modulation in urine flow and Na(+)-excretion following renal alpha 2 adrenoceptor stimulation. An upregulation of imidazoline receptors in hypertension may contribute to the effects observed.

4-Aminopyridine↗
PubMed1997

p53 immunohistochemical staining predicts residual disease after chemoradiation in patients with high-risk rectal cancer.

This study was conducted to investigate the value of p53 immunohistochemical staining of pretreatment biopsy specimens in predicting the response of rectal cancer to chemoradiation. The study group comprised 42 patients with high-risk rectal cancer treated between July 1990 and July 1995 with a preoperative chemoradiation regimen of 45 Gy of external-beam irradiation and continuous-infusion 5-fluorouracil followed by surgical resection. p53 immunohistochemical staining was performed on pretreatment biopsy specimens. p53 immunohistochemical staining pattern and standard clinical and pathological parameters were correlated with extent of residual cancer in the surgical specimen. Twenty tumors were positive for p53 on immunohistochemical staining, 19 were negative, and 3 were focally positive. Thirteen patients experienced a complete response to chemoradiation. Aberrant p53 protein accumulation, as measured by immunohistochemical staining, correlated inversely with a complete pathological response to chemoradiation (P = 0.005; correlation coefficient = -0.43) and directly with an increased likelihood of residual cancer in the lymph nodes of surgical specimens (P = 0.02; correlation coefficient = 0.39). p53 immunohistochemical staining of pretreatment biopsy specimens correlates with the extent of residual disease after chemoradiation in patients with high-risk rectal cancer.

Adult↗
PubMed1997

Prognostic significance of glutathione S-transferase pi expression and subcellular localization in human gliomas.

The glutathione S-transferase (GST)-pi gene is overexpressed in many human cancers and preneoplastic lesions and is associated with failure of cancer chemotherapy and poor patient survival. Although GST-pi overexpression in tumors of the central nervous system has been observed, the prognostic and/or clinical relevance of this overexpression has, to date, not been investigated. In this study, we analyzed the level of GST-pi expression and its subcellular localization in 61 primary gliomas and correlated the results with tumor histology, patient age, and patient survival. We observed a strong positive correlation between the level of GST-pi expression and tumor grade and between the presence of GST-pi in glioma cell nuclei and patient age. Univariate and multivariate Cox regression analyses and Kaplan-Meier curves showed the level of GST-pi expression and its nuclear localization to be inversely correlated with patient survival. Relative risk for death of patients with high versus low tumor GST-pi expression was 3.2 (P = 0.0069) by univariate analysis and 2.6 (P = 0.036) by multivariate analysis. The relative risk of death associated with the presence of nuclear GST-pi in glioma cells was 3.9 (P = 0.0001) by univariate analysis and 4.4 (P < 0.0001) by multivariate analysis. These data indicate that high GST-pi expression in tumor cells and the presence of the GST-pi protein in tumor cell nuclei are associated with clinically more aggressive gliomas and are strong predictors of poor patient survival.

Adolescent↗
PubMed1995

[Assessment and diagnosis of transient ischemic attacks].

Transient ischemic attacks (TIA) are defined as acute, retinal or focal-cerebral neurological symptoms, resulting from vascular disease, which resolve in less than 24 hours. Typical clinical signs are transient visual obscuration, sudden weakness of one arm or leg, loss of speech, and dizzy spells. These patients run a considerable risk of stroke; hence rapid diagnosis and treatment are mandatory. Differential diagnosis includes transient global cerebral function loss, non-vascular transient focal attacks, as well as extracerebral causes of transient neurological symptoms. The following basic investigations are necessary for most patients with TIA: simple laboratory work-up, extra- and transcranial doppler/duplex-ultrasonography, cardiological examination and CT-scan. Angiography and MR-angiography are reserved for specific questions.

Brain Diseases↗
PubMed1995

Stimulation of translation by reactive oxygen species in a cell-free system.

Wheat germ lysate was used as a model system for in vitro translation. We show that an increase of the exchange surface between the reaction mixture and the atmosphere enhanced the amount of incorporated cysteine, indicating that early arrest of protein synthesis previously observed in such a system was due to oxygen starvation in the reaction mixture. This hypothesis was confirmed since the amount of proteins synthesized and the rate of translation increased when oxygen was added. We show that an addition of hydrogen peroxide to the translation mixture had the same effect as oxygen, allowing us to postulate that stimulation could be due to a common property between both molecules: the oxidizing behaviour. Free radicals in in vitro translation were believed to be involved since the utilization of iron chelating agents inhibited translation. This hypothesis was emphasized by the positive effect of a free radical generating system and the negative effect of free radical scavengers. These experiments suggest that the superoxide radical plays an important role in in vitro translation.

Cell-Free System↗
PubMed1994

Expression of secreted recombinant human insulin-like growth factor-II (IGF-II) in Chinese hamster ovary cells.

Chinese hamster ovary (CHO-KI) cells were cotransfected with a plasmid pcDNAI containing the human preproinsulin-like growth factor II cDNA linked downstream to the human cytomegalovirus promoter and with a plasmid containing the neomycin resistance gene (pMAM-neo). CHO neo+ were selected by growth in medium supplemented with G418 geneticin. After amplification, the neomycin-resistant clones were screened for IGF-II production. IGF-II produced was identified by dot blot and quantified by ELISA. The clones C24, C40 and C94 secreted IGF-II at about 350-400 ng per 10(6) cells per day. DNA analysis of C24 and C40 CHO cells by PCR demonstrated the presence of the IGF-II construct in the transfected cells, presumably integrated into the chromosomal DNA. IGF-II produced by CHO cells and purified by RP-HPLC was a mitogen for MCF-7 stimulating mitosis 2-fold.

Animals↗