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Biomedical subjects

S Keller

Publications and source records attributed to S Keller.

At least 73 records · Page 4Linked to original sources
PubMed1995

Quantity and quality of venom released by a spider (Cupiennius salei, Ctenidae).

The amount of venom injected by the spider Cupiennius salei depended on the efficiency of the mechanical defence of the prey species. Spiders were milked for the first venom (i.e. the first microlitre of venom emitted) versus remaining venom, and for venom regenerated from emptied glands. HPLC gel filtration and IEF electrophoresis showed that the protein content of the first venom was only half as compared to that of the remaining venom, and that this was due to a dilution of all proteins. Venom regeneration came in two speeds. The amount of venom was regenerated more rapidly than the protein concentration. Newly regenerated venom as compared to older venom was characterized by a lower concentration of all proteins and by a higher total concentration of free amino acids, whereas histamine and taurine did not follow this trend. K+ concentration and pH remained similar during venom regeneration. Crickets injected with the venoms showed less acute symptoms when the protein concentration was lower, namely with the first venom and with newly regenerated venom. Consequently, a spider which modulates the quantity of venom injected into a prey also directly changes the venom quality. The ecological consequences of this are discussed. This paper also discusses which region of a gland (ampulla, extracellular and intracellular parts of the glandular sac) is involved in the changes of the venom quality.

Amino Acids↗
PubMed1995

Acute promyelocytic leukemia.

Significant advances have occurred in the diagnosis, treatment, and long-term outcome of patients with acute promyelocytic leukemia (APL). The purpose of this review is to describe the molecular genetics of this disease, the use of all-trans retinoic acid (ATRA) in clinical trials of APL, and the clinical and basic research questions for future investigation. Findings of clinical studies in mainland China using ATRA as induction therapy for patients with APL concurrent with laboratory characterization of the molecular changes in APL have led to worldwide clinical trials of ATRA in the treatment of patients with APL. Major advances in understanding the molecular biology and genetics of APL have occurred over the past 5 years. These findings have been translated into novel treatment strategies using all-trans retinoic acid as a differentiation agent in the induction phase of therapy resulting in improved long-term outcome, reduced morbidity, and lower costs for patients with APL. Advanced molecular techniques are being employed for diagnosis and for monitoring of patient response to treatment.

Child↗
PubMed1994

Survival following resection of clinically occult N2 non small cell lung cancer.

BACKGROUND: The role of resection in Stage IIIA (N2) non-small cell lung cancer (NSCLC) remains controversial despite reported survival rates of 25-40%. This study was undertaken to identify factors associated with a high risk of treatment failure after resection of clinically occult Stage IIIA (N2) NSCLC: Such prognostic factors may identify high risk patients as candidates for future clinical trials of multimodality lung cancer treatment and be important stratification factors in such trials. METHODS: The clinical and pathological records of 32 patients with clinical NO pathologic N2 NSCLC who underwent lobectomy (n = 17), pneumonectomy (n = 12), or bilobectomy (n = 3) and complete mediastinal lymph node dissection at Fox Chase Cancer Center from 1987 to 1991 were reviewed. A multivariate analysis of clinical and pathologic variables was performed. RESULTS: Median follow-up was 15 months (range 5-55). Fifty-nine percent have recurred and 44% have died. Median disease free and overall survival were 16 and 19 months, respectively. Two year disease free and overall survival were 24% and 43%, respectively. No patient with more than one level of mediastinal lymph node metastases survived two years free of disease. Univariate and multivariate analysis revealed a longer disease free survival for those receiving adjuvant radiation therapy (19 vs 5 months) but no increase in overall survival. CONCLUSIONS: This experience with clinically occult Stage IIIA (N2) NSCLC suggests that multiple levels of mediastinal lymph node metastases predict treatment failure in patients following resection and that adjuvant mediastinal radiation improves disease free but not overall survival.

Adult↗
PubMed1994

Analysis of elastin cross-linking and the connective tissue matrix of abdominal aortic aneurysms.

BACKGROUND: Studies of the connective tissue matrix of abdominal aortic aneurysms (AAAs) have yielded conflicting results, and the glycosaminoglycan content has not been previously reported. The present work was done to evaluate the matrix components of AAAs, including the cross-link content of the residual elastin. METHODS: Aortic specimens from AAAs and controls were sequentially extracted with salt, Brij, and urea; and the residual pellets were the subject of further studies. Elastin was purified by hot alkali treatment; other matrix components were determined by conventional methods. RESULTS: Elastin content of the purified material was reduced in AAA. The cross-link content, desmosine+isodesmosine, was also reduced in AAA as a ratio to insoluble matrix dry weight. However, the cross-link content as a ratio to valine in the purified elastin was normal. The amino acid profiles of representative AAA and controls elastin preparations were similar to that of reference elastin. The amino acid content of the insoluble matrix of AAA revealed a significant reduction of protein (controls = 820 +/- 40 micrograms/mg versus AAA = 700 +/- 20 micrograms/mg, p < 0.05); the collagen content was unaltered. The content of glycosaminoglycan in AAA was noted to be significantly reduced (controls = 33.5 +/- 3.4 micrograms/mg versus AAA = 17.1 +/- 2.0 micrograms/mg, p < 0.05). CONCLUSIONS: The data do not support the hypothesis of a primary cross-link deficiency in elastin of AAA; but the reduced contents of protein and glycosaminoglycans in AAA suggests basic biochemical alterations in the diseased aorta that warrant further investigation.

Amino Acids↗
PubMed1992

International Quality of Life Assessment (IQOLA) Project.

The International Quality of Life Assessment (IQOLA) Project is a 4-year project to translate and adapt the widely used MOS SF-36 Health Survey Questionnaire in up to 15 countries and validate, norm, and document the new translations as required for their use in international studies of health outcomes. In addition to the eight-scale SF-36 health profile, the project will also validate psychometrically based physical and mental health summary scores, as well as health utility indexes incorporating SF-36 scales for use in cost-utility studies.

Europe↗
PubMed1992

Should patients with post-resection locoregional recurrence of lung cancer receive aggressive therapy?

The outcome of thirty-seven patients with a post-resection locoregional recurrence of non-small cell lung cancer treated with radiation therapy alone between 1979 and 1989 was compared to that of 759 patients with unresected non-small cell lung cancer also treated with standard radiation during the same period. Each patient's locoregional recurrence was staged using the current American Joint Committee on Cancer staging system. Comparison of pretreatment characteristics between the two groups, including age, sex, extent of weight loss, performance status, stage, and histologic subtype revealed fewer patients with greater than 5% weight loss (35 vs. 47%, p = 0.04) and more cases with squamous histology (54 vs. 28%, p = 0.01) among the patients with locoregional recurrences than those with newly diagnosed lesions. Over 80% of both groups had clinical stage III lesions. The median radiation doses were 56 and 59 Gy for recurrent and newly diagnosed cases (p = NS). For the patients with locoregional recurrences, the median time from resection to recurrence was 13 months (range: 3-118 months), and the recurrences were predominantly nodal in 25 cases, chest wall/pleural in four and at the bronchial stump in eight. When measured from the date of documented recurrence, the median survival time and 2-year actuarial survival rate of the patients with recurrent lesions were 12 months and 22%, as compared to 12 months and 26% for the newly diagnosed patients (p = NS). Freedom from documented locoregional tumor progression at 2 years was 30% for both groups. Patients with bronchial stump lesions had superior survival to those with nodal or chest wall recurrences, with a median survival time of 36 versus 9 months. A therapeutic approach to selected patients with post-resection locoregional recurrence of non-small cell lung cancer equally aggressive to that for newly diagnosed lung cancer patients is justified by these results, especially for patients with bronchial stump recurrences.

Adult↗