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Results for “Biological Factors”

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At least 19 recordsLinked to original sources
PubMed1975

Studies in breath-alcohol analysis: biological factors.

Various biological factors affecting breath-alcohol analysis were studied experimentally. End-expiratory temperatures in 55 healthy subjects were found to range from 32.41 to 35.69 degrees C with a mean of 34.53 degrees C. Forced vital capacity in the same subjects ranged from 1825 to 6550 ml with a mean of 4038 ml, and maximum exhalation after normal inhalation ranged from 1180 to 4550 ml with a mean of 2730 ml. It was found that 65-70% of available breath must be discarded before the alveolar plateau is reached during expiration. End-expiratory (alveolar) carbon dioxide in 155 healthy subjects was 3.5-8.3% by volume (mean = 6.52). After oral alcohol intake, retained mouth-alcohol in 8 subjects had disappeared after 11 minutes without subsequent water-rinsing of the mouth, and after 8 minutes with rinsing. Water condensation in plastic mouthpieces/saliva traps during breath sampling yielded mean weight gains of 13.0, 8.6, and 4.6 mg., respectively, at initial mouthpiece temperatures of 3 degrees C, 22.5 degrees C, and 34.7 degrees C, respectively.

Air↗
PubMed1977

Studies on lymph humoral factor. Biological characteristics of a lymphocytopoietic factor in rat thoracic duct lymph.

The biological characteristics of a lymphocytopoietic factor obtained from rat thoracic duct lymph (Yamashita, Fukumoto & Miyamoto, 1976) were further investigated. The lymph extract from normal rats failed to stimulate both large pyroninophilic cell-proliferation and mitotic response in the spleen and lymph node of the thymectomized, irradiated and marrow reconstituted rat (B rat). This suggests that target or responsive cells for the factor are not marrow-derived (B) cells, but thymus-derived (T) cells. On the other hand, the lymph extract from the lymphopenic lymph-drained B rats showed similar high lymphopoietic activity to those of normal rats, indicating that the existence of a thymus is not essential for the production or secretion of the factor. The fact that lymphocytotic rats produced by syngeneic lymphocyte transfusion are most sensitive to the lymph extract suggests that liver endogenous level of this factor and the responsiveness of target cells are regulated by the number of circulating T lymphocytes.

Animals↗
PubMed1993

The importance of non-biological factors in influencing the outcome of clinical trials.

The outcome of clinical drug trials is influenced both by biological and by non-biological factors. Non-biological factors can be subdivided into methodological factors and non-drug factors. The former are related to the definition and measurement of treatment course, response, and outcome itself; the latter cover characteristics of the patient, the treatment milieu, the patient's milieu apart from treatment, and (planned) psychosocial interventions. Although their mechanism of interaction with treatment outcome is not yet fully understood, these non-drug factors should be routinely monitored in clinical trials for three practical reasons: (a) to control for the heterogeneity of outcome; (b) to develop individualised outcome predictors; and (c) to promote the development of individualised guidelines for treatment indication.

Clinical Trials as Topic↗
PubMed1983

Biological factors and crime: implications for forensic psychiatry.

To summarize, we can say that (1) Criminal behavior, especially chronic criminal behavior, seems to be partly genetically predisposed; (2) An important task at this point is to attempt to determine the biological factors which predispose people to crime; and (3) We have related some tentative initial steps being taken in the study of the autonomic nervous system as one possible heritable, biological basis for the failure of normal social learning forces in inhibiting criminal behavior. Early in this paper we discussed the tenability of asserting criminal responsibility on individuals whose criminal behavior has a partly genetic etiology. But this special consideration seems to set biological factors apart as being in some unique causal category. In fact, genetic, physiological, and biochemical factors are causal agents in the same sense as family, social class, or neighborhood factors. Of course, criminal behavior (like all other behavior) must be caused; one class of causal variables is the biological category. The legal doctrine of responsibility is not challenged by identifying biological factors as partially determining crime any more than it is by findings of social causation. Only in cases in which abnormal biological factors are exceptionally powerful influences might responsibility be challenged. Such cases will be quite rare.

Adoption↗
PubMedDate not supplied

The interaction of sociological and biological factors in adolescent cigarette smoking.

This article considers the interaction of social and biological factors in the context of adolescent cigarette smoking. Parent and peer smoking are the sociological variables and testosterone is the biological indicator. The subjects are 212 males and females 12-14 years of age. The findings support the interaction model, suggesting that both sociological and biological factors are necessary for understanding adolescent smoking.

Adolescent↗
PubMed1997

The association of yeasts and denture stomatitis with behavioral and biologic factors.

OBJECTIVES: This study describes the association of yeasts and denture stomatitis with behavioral and biologic factors. STUDY DESIGN: Seven hundred eighty 55-year-old citizens of Oulu, Finland, were examined clinically; 452 of them had complete dentures. Salivary yeasts and lactobacillus counts were detected through the use of Oricult-N and Dentocult-LB dip-slide techniques. Lifestyle factors were measured by means of questions concerning physical activity, tobacco smoking, alcohol consumption, and dietary habits. Other background variables used in cross-tabulations and logistic regression analysis were unstimulated salivary secretion rate, retention of denture, oral hygiene, gender, and socioeconomic status. RESULTS: The prevalence of denture stomatitis was greater among subjects with an unhealthy lifestyle, subjects with higher lactobacillus counts, and subjects with poor oral hygiene. Salivary secretion rate and smoking were associated with the presence of yeasts, but general lifestyle measures were not. CONCLUSION: The presence of yeasts tended to be associated with biologic factors, but behavioral factors reflecting lifestyle may be more important in the development of denture stomatitis.

Alcohol Drinking↗
PubMed1992

Identification of multiple biological factors in rabbit serum that modulate dopamine-mediated aortic constriction.

A bioassay was established using freshly prepared rabbit aortic strip to monitor the effects of various biological factors contained in rabbit serum that modulate vasoconstriction. Serotonin was shown to be a major vasoconstriction modulator in rabbit serum. A rapid procedure is described for its isolation from rabbit serum by sequential gel filtration chromatography and reversed-phase HPLC using C4, C18, and C2/C18 columns with an overall cumulative yield of about 20%. It was also noted that rabbit serum contains multiple biological factors that modulate dopamine-mediated aortic contraction other than serotonin. A potent vasoconstriction inhibitor was identified in rabbit serum which appears to be a novel regulator that mediates its effect via both alpha-adrenergic and serotonin receptors.

Animals↗
PubMed1984

[The influence of galenic and biologic factors on the bioavailability of Berlocombin].

The analysis of the influence of galenical and biological factors on the biological availability of Berlocombin (sulfamerazin and trimethoprim combination) has been performed by a single Berlocombin juice administration compared to tablets and by a tablet administration combined with nourishment. In case of the juice administration, the biological availability of trimethoprim and sulfamerazin has been reduced. The tablet administration at an empty stomach and a subsequent 5-h waiting period revealed a more complete trimethoprim resorption, which compared to an administration immediately after the standard breakfast is expressed by a significantly greater area under the concentration-time curve (AUC) in serum. In tablet application subsequent to a fatty breakfast, the trimethoprim and sulfamerazin resorption is compared to the relative group some increased; the differences, however, were insignificant ones. The results of this study failed to be of practical consequences, because the dosage applied and recommended by the producer significantly exceeded the minimum inhibition concentrations in serum and urine 3 h after administration. The required therapeutic level in no case fell short of up to the 12. hour.

Administration, Oral↗
PubMed1994

Facilins, a novel class of biological factors that facilitate the aortic response to dopamine and other biogenic amines.

Biological fluids and tissues extracts were shown to contain biological factors, termed facilins, that facilitate the dopamine-, adrenaline-, and serotonin-mediated aortic contraction at concentrations devoid of any direct effect. Cyproheptadine and phentolamine antagonized the direct contracting effect of biogenic amines, but not the facilitated component of the aortic response thus indicating that the mechanism of action of facilins was unlike that of biogenic amines. Fresh schizophrenics' CSF displayed a stronger facilitating effect than normal CSF on the dopamine-mediated aortic response. This finding, however, was not confirmed with samples kept frozen for prolonged periods of time. Multiple molecular forms of facilins were detected in rabbit serum. Those with a high apparent molecular weight were proteinous and were neither insulin nor other factors known for their contracting effects on the aorta such as epidermal growth factor, transforming growth factor-beta, and platelet-derived growth factor.

Adrenal Glands↗
PubMed1990

[Biological factors as occupational hazards in agriculture].

The article provides data obtained from both the national and foreign publications on the role of the biological factor in modern agricultural production. An account of the agricultural branches is given in which the role of this factor is most predominant. Particular emphasis is laid on the diversity of its influence on man with resulting allergies, infections and intoxications, and on the necessity of the standardization of most hazardous biological factors.

Agricultural Workers' Diseases↗
PubMed1992

Multiparametric prognostic evaluation of biological factors in primary breast cancer.

BACKGROUND: An array of biological features related to tumor cell differentiation status, growth rate, and invasive potential have been identified as potential prognostic factors in breast cancer. We were interested in determining their relative importance in predicting patient survival. PURPOSE: We evaluated the relative weight of the following four biological factors in predicting survival of patients with breast cancer: tumor cell DNA content (determined by flow cytometry), tumor cell proliferation rate (determined by thymidine kinase activity), expression levels of cathepsin D and urokinase plasminogen activator, and several "classical" clinical and histological factors. METHODS: Selected from a prospectively updated database, the study population consisted of 319 primary breast cancer patients who received treatment and follow-up care (median, 6 years) in the Centre René Huguenin. To determine the profile of biological factors for each patient, we used frozen tumor specimens and (except for the flow cytometric DNA content assay) commercially available assay kits. We determined by Cox multivariate analysis the relationships of the biological factors to each other, to classical prognostic factors, and to disease-free and metastasis-free survival. RESULTS: In the overall population, disease-free survival was best predicted by node status (P = .004), clinical tumor size (P = .02), and cathepsin D expression (P = .01), whereas metastasis-free survival was best predicted by node status (P = .0004), clinical tumor size (P = .009), and urokinase plasminogen activator expression (P = .04). In node-negative patients, thymidine kinase activity was the only factor selected for disease-free (P = .04) and metastasis-free (P = .05) survival. In node-positive patients, the number of positive axillary lymph nodes was the only factor selected for disease-free (P = .0008) and metastasis-free (P = .00017) survival. CONCLUSIONS: Our retrospective analysis has identified protease expression and tumor cell proliferation rate as important biological prognostic factors in breast cancer. Prospective clinical trials should be undertaken to confirm these results.

Adult↗
PubMedDate not supplied

Biological factors and predictability of bracing in adolescent idiopathic scoliosis.

Biological factors that could have a predictive value in treating idiopathic scoliosis by brace were studied in 107 patients (102 girls and 5 boys). The mean age of the patients was 14 years 6 months, and the mean Cobb angle of the curves was 36 degrees at start of treatment. The Boston brace was used for an average of 1 year 6 months, and mean follow-up time after weaning was 3 years. Scoliosis with an apex of Th 10-12 proved to be the most favorable for the final result, with a mean correction of 2 degrees. All other curves remained unchanged. Patients who had a period of rapid growth just before or during treatment had a better final result than the others. The final result was also better when treatment was started before menarche.

Adolescent↗
PubMed1995

[Biological factors and resistance to antidepressive agents].

Concerning depressive disorders, biological factors remain relatively unknown. However, they might first be risk factors for depressive disorders and secondly could decrease the response to antidepressants. We studied hypothyroidism, diabetes and hypothalamic-pituitary-adrenal axis disorders. In terms of neurotransmitters, beta-adrenergic dysfunction may be involved in hypothyroidism and diabetes whereas a serotonergic dysfunction may be involved in hypothalamic-pituitary-adrenal axis disorders.

Animals↗
PubMed1989

Biologic factors in the sexual transmission of human immunodeficiency virus.

The probability that any single episode of genital-genital or anogenital sexual intercourse will result in transmission of HIV may be determined by multiple biologic factors of the infectious person, the virus itself, and the exposed susceptible person. Some of these factors are known or suspected (figure 1), and they may explain observed differences in the sexual transmission of HIV in different parts of the world, notably in Africa, where genital ulcerative disease is probably influencing the epidemiology of HIV. Several studies have shown that infection in partners of HIV-infected persons is not determined solely by numbers of sexual encounters; on the contrary, HIV-infected partners have usually had fewer sexual encounters with infectious mates than have noninfected partners. Thus, sexually active persons should be cautioned that, to our knowledge, there are no nonsusceptible persons and that any single unprotected sexual encounter may lead to HIV transmission. Research into biologic factors that modulate HIV transmission continues to be hampered by difficulties in identifying HIV transmitters and nontransmitters, infective and noninfective variants of HIV (if the latter exist in vivo), and persons relatively more or less susceptible to HIV infection. However, as the number of partner studies and the number of those enrolled in them increase, a progressively clearer idea of the biologic determinants of sexual transmission of HIV should emerge.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Prognostic significance of three novel biologic factors in a clinical trial of adjuvant therapy for node-negative breast cancer.

BACKGROUND: Five products of human breast carcinoma cells, including membrane-associated phospholipase A2 (M-PLA2), polymorphonuclear leukocyte elastase (PMN-E), tissue-type plasminogen activator (t-PA), urokinase-type plasminogen activator (u-PA), and endothelin-1 (ET-1), have been implicated in the processes of tumor cell invasion and metastasis in human breast carcinoma. However, the prognostic significance of these factors has not been assessed previously in node-negative breast carcinoma, in which adjuvant treatment is dependent on risk stratification. METHODS: The five products of breast carcinoma cells were measured in 184 patients with node-negative breast carcinoma who were enrolled in the Kumamoto Adjuvant Chemo-Endocrine Therapy for Breast Cancer prospective randomized trial, and the predictive values of these factors for relapse-free and overall survival were evaluated. RESULTS: M-PLA2, PMN-E, and t-PA were found to be significant independent predictors of relapse-free and overall survival, whereas u-PA and ET-1 were not independently predictive. Further statistical analyses showed that the predictive powers of M-PLA2, PMN-E, and t-PA were additive. A combination of these three factors identified a group of patients (approximately 50% of those who manifested node-negative breast carcinoma) with a favorable prognosis, regardless of the administration of adjuvant therapy. CONCLUSIONS: This study identified three biologic factors that are valuable predictors of survival in node-negative breast carcinoma. A combination of these biologic factors may allow identification of low-risk patients who could be spared adjuvant therapy.

Breast Neoplasms↗
PubMed1995

Effects of biological factors on cell growth and anthocyanin formation by suspended cultures of Perilla frutescens cells.

Effects of biological factors (i.e., size of cell aggregates, subculture period, and inoculum density) on cell growth and production of anthocyanin pigment (a secondary metabolite) by suspended cultures of Perilla frutescens plant cells were investigated on a flask scale. It was found that anthocyanin content was lower in a culture inoculated with cells of size greater than 250 microns, compared with unscreen-sized cells or cells smaller than 250 microns. Subculture periods of 7 and 10 days were suitable for the cell cultures since favorable growth and a high level of anthocyanin content were maintained during a long period of subculture. An inoculum density (wet cells) of 50 g/L was the best for both the cell growth and pigment accumulation in flask culture of P. frutescens cells.

Anthocyanins↗
PubMed1998

Prognostic significance of pathological and biological factors in hepatocellular carcinoma.

Prognostic factors in hepatocellular carcinoma (HCC) conventionally consist of staging with the tumour node metastasis system and grading by tumour cellular differentiation. There are also other factors useful in prognostication but most of them are clinical. With new discoveries in the pathobiology of cancers and introduction of new medical technology, pathological and biological factors of HCC in relation to prognosis have been studied quite extensively. Morphological features of the tumour, both gross and histological, have been found to be significantly related to tumour recurrence and patient survival. Recently, applications of new antibodies and techniques have enabled studies on cellular proliferation using different antibodies such as those for proliferating cell nuclear antigen and Ki-67 protein. These studies on cellular proliferation, as well as assessment of argyrophilic nucleolar organizing regions, have been shown to provide good prognostic significance. Flow cytometric studies on DNA ploidy and studies on expression of genes including the p53 gene, hormone receptors and others show less unanimous results in their prognostic significance. The influence of gender on survival is also reviewed. In conclusion, pathological and biological factors are useful and help to guide clinicians in the management of patients and in assessment of long-term prognosis.

Biomarkers↗