PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Biological Factors”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed2006

Biological factors.

Biological factors such as saliva, acquired dental pellicle, tooth structure and positioning in relation to soft tissues and tongue are related to dental erosion development. Saliva has been shown to be the most important biological factor in the prevention of dental erosion. It starts acting even before the acid attack, with the increase of the salivary flow rate as a response to the acidic stimuli. This creates a favorable scenario, increasing the buffering system of saliva and effectively diluting and clearing acids on dental surfaces during the erosive challenge. Saliva plays a role in the formation of the acquired dental pellicle, which acts as a perm-selective membrane preventing contact of the acid with the tooth surfaces. The protective level of the pellicle seems to be regulated by its composition, thickness and maturation time. Due to its mineral content, saliva can also prevent demineralization as well as enhance remineralization. However, these preventive and reparative factors of saliva may not be enough against highly erosive challenges, leading to erosion development. The progress rate of erosion can be significantly influenced by the type of dental substrate, occurrence of mechanical and chemical attacks, fluoride exposure, and also by contact with the oral soft tissues and tongue.

Biology↗
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↗
PubMed2002

[Histopathologic prognostic factors, serum markers and selected molecular biologic factors in ovarian carcinoma].

OBJECTIVE: A review of histopathological prognostic factors, serum markers and selected molecular biological factors in ovarian cancer. DESIGN: Review. SETTING: Department of Obstetrics and Gynaecology, Medical Faculty Hradec Králové, Charles University, Prague; Department of Biological and Medical sciences, Pharmaceutical Faculty, Hradec Králové, Charles University, Prague; Department of Clinical Oncology, Medical Faculty Hradec Králové, Charles University, Prague; Bristol-Myers Squibb, Department of Oncology, Prague. METHOD: Discussion about current evidence from literature. CONCLUSION: Except clinical prognostic factors the wide spectrum behaviour of epithelial ovarian cancers is reflected by some histopathological prognostic factors, serum markers and some molecular biological factors. The most important are grade and tumor ploidy, the level of CA 125 and its changes during the treatment, mutations of p53, BRCA 1 and 2.

Biomarkers, Tumor↗
PubMed2004

[Biological factors in eating disorders].

The etiology of eating disorders has not been defined yet. It is generally thought of as multi-dimensional, consisting of socio-cultural, psychological and biological factors. The biological factors include predisposing, precipitating and perpetuating factors. In recent years, genetics have been reported as predisposing factors, various neuropeptides which play an important role in regulation of feeding behavior have been discovered to be precipitating factors, and brain imaging studies investigating morphological changes have revealed perpetuating factors. This review gives an outline of recent information about biological factors in eating disorders.

Brain↗
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↗
PubMedDate not supplied

Biological factors and therapeutic modulation in prostate cancer radiotherapy.

Biologic factors affect the ability of radiation to effectively treat all patients with prostate cancer. The use of prognostic and genetic markers (12 lipoxygenase, p53, bc1-2 genes, ploidy) may aid in the development of treatments for these patients. Particularly, several studies have shown that p53 tumor suppressor gene mutations are infrequent in prostate cancer and are associated with advanced disease. Recent efforts have been directed toward novel therapeutic modalities, especially in combination with standard irradiation of prostate carcinoma. These modalities are based on an improved knowledge of these biological factors involved in the progression and diffusion of the tumor, especially p53. Several authors evaluated the predictive and prognostic role of p53 in patients with prostatic cancer treated with radiotherapy. An extensive review of international reports on the subject is provided.

Biological Factors↗
PubMed2005

Tumour targeting: biological factors and formulation advances in injectable lipid nanoparticles.

Cancer chemotherapeutic agents are often administered systemically. Following systemic administration, numerous biological factors associated with the tumours influence the delivery of the drugs to the tumours. These factors have been extensively studied for the last 2 decades. The influence of these biological factors has brought about a drastic change in the design of drug delivery systems to solid tumours. This review discusses the various biological factors influencing drug delivery to tumours and the subsequent development of injectable delivery systems (i.e., lipid-based nanoparticles (SLNs)) for adequate delivery of drug to solid tumours.

Animals↗
PubMed2004

Immunohistochemical analysis of tumor biological factors in hepatocellular carcinoma: relationship to clinicopathological factors and prognosis after hepatic resection.

BACKGROUND: The relationship between patient prognosis and various tumor biological factors has been reported previously, and prognostic factors of tumor biology may improve predictions of prognosis after hepatectomy for hepatocellular carcinoma (HCC) and may contribute to a new staging classification. This study was designed to provide an immunohistochemical analysis of tumor biological factors in patients who underwent hepatectomy for HCC. METHODS: Factors analyzed included p53 overexpression, microvessel counts, proliferating cell nuclear antigen, and expression of nm23. We examined 81 HCCs from patients with chronic liver diseases. RESULTS: In patients who underwent chemoembolization before surgery, or those a who had confluent multinodular tumor, p53 expression tended to be higher than in patients without chemoembolization (33% vs 11%) or those with a simple nodular tumor (28% vs 10%), but the difference was not statistically significant ( P = 0.051 and P = 0.092, respectively). A lower tumor microvessel count and negative nm23 expression were significantly associated with poor disease-free survival by univariate analysis ( P < 0.01 and P < 0.05, respectively). A lower tumor microvessel count was found to be a significant prognostic factor for disease-free and overall survivals (risk ratios, 2.44 and 3.13, respectively; P << 0.05), in addition to tumor size, vascular invasion, and longterm ascites, by Cox's multivariate analysis. CONCLUSIONS: Tumor microvessel count appears to be a useful prognostic marker for predicting HCC recurrence and patient survival.

Adult↗
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↗
PubMed2002

Y-box factor YB-1 predicts drug resistance and patient outcome in breast cancer independent of clinically relevant tumor biologic factors HER2, uPA and PAI-1.

Intrinsic or acquired resistance to chemotherapy is responsible for failure of current treatment regimens in breast cancer patients. The Y-box protein YB-1 regulates expression of the P-glycoprotein gene mdr1, which plays a major role in the development of a multidrug-resistant tumor phenotype. In human breast cancer, overexpression and nuclear localization of YB-1 is associated with upregulation of P-glycoprotein. In our pilot study, we analyzed the clinical relevance of YB-1 expression in breast cancer (n = 83) after a median follow-up of 61 months and compared it with tumor-biologic factors already used for clinical risk-group discrimination, i.e., HER2, urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor type 1 (PAI-1). High YB-1 expression in tumor tissue and surrounding benign breast epithelial cells was significantly associated with poor patient outcome. In patients who received postoperative chemotherapy, the 5-year relapse rate was 66% in patients with high YB-1 expression. In contrast, in patients with low YB-1 expressions, no relapse has been observed so far. YB-1 expression thus indicates clinical drug resistance in breast cancer. Moreover, YB-1 correlates with breast cancer aggressiveness: in patients not treated with postoperative chemotherapy, those with low YB-1 expression are still free of disease, whereas the 5-year relapse rate in those with high YB-1 was 30%. There was no significant correlation between YB-1 expression and either HER2 expression or uPA and PAI-1 levels. Risk-group assessment achieved by YB-1 differed significantly from that by HER2 or uPA/PAI-1. In conclusion, YB-1 demonstrated prognostic and predictive significance in breast cancer by identifying high-risk patients in both the presence and absence of postoperative chemotherapy, independent of tumor-biologic factors currently available for clinical decision making.

Adult↗
PubMed1999

Prognostic significance of biologic factors in squamous cell carcinoma of the esophagus.

BACKGROUND: Esophageal carcinoma is one of the most lethal tumors. Therefore, it is important to identify prognostic factors for patients with this disease. The objective of this study was to clarify the relation between clinicopathologic and biologic factors in esophageal carcinoma and to determine the prognostic significance of different biologic factors. METHODS: DNA ploidy pattern, Ki-67 labeling index (LI), and cyclin D1 and p53 protein expression were examined and detailed pathologic examinations were conducted on tumors from 53 patients (46 males and 7 females with a mean age of 66 years [range, 47-85 years]) with surgically resected esophageal squamous cell carcinoma and the prognostic value of these factors was evaluated. RESULTS: Of the 53 esophagus carcinomas examined, 26 (49%) were classified as DNA diploid. The mean Ki-67 LI was 45 +/- 4. 9% (range, 10.5-86.1%). p53 expression was detected in 38 of the carcinomas (71.7%) and cyclin D1 expression was detected in 35 (66%). Various prognostic factors were examined using the Cox stepwise regression model, four of which were found to correlate with overall survival: tumor size (P = 0.0346), lymph node status (P = 0.0384), Ki-67 LI (P = 0.0161), and p53 expression (P = 0.001). Lower Ki-67 LI and a lower rate of p53 expression were detected in the long term survival group (> 3 years) compared with the short term survival group (P = 0.00045 and P = 0.0023, respectively). CONCLUSIONS: The biologic factors of Ki-67 LI and p53 expression, as well as clinicopathologic factors, may be used as independent prognostic factors for patients with esophageal carcinoma. However, the results of the current study do not support cyclin D1 expression as a prognostic factor.

Aged↗
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↗
PubMed2004

Time of farmers' exposure to biological factors in agricultural working environment.

Working time in conditions of exposure to hazardous factors is an important element indispensable for the evaluation of human exposure in the working environment. Agricultural work is accompanied by co-occurrence of many risk factors threatening farmers' health, e.g. dust, elements of the thermal environment, noise, vibration, chemical and biological agents. Biological factors cause diseases with contagious, allergic or immuno-toxic backgrounds which constitute the majority of farmers' occupational diseases registered in Poland. Exposure to hazardous factors in agricultural working environment is due to contact with plants, animals and organic wastes, more precisely--with microbes, plant and animal particles present in aerogenic agricultural dust, as well as pathogens of contagious and invasive diseases present in contaminated soil, water and plants. Data concerning the duration of farmers' exposure to biological and other factors of the working environment were obtained with the use of the Private Farmer Work Chart. Time-schedule observations concerned an annual work cycle. The study covered 30 farms with the following production profiles: plant (Group A), animal (Group B) and mixed production (Group C). The total working time was: in Group A - from 106-163 % of the legal working time; in Group B - from 75-147 %; in Group C - from 136-167 %. Among 48 work activities contributing to the full working cycle among the farmers examined, 15 activities were accompanied by 5 factors. These were mainly field activities which covered plant harvesting and fertilizing, chemical plant protection, as well as cultivation activities. Agricultural dust and elements of the thermal environment were the environmental factors most frequently accompanying agricultural work, followed by contact with biological factors, noise, vibration, and chemical agents. Biological factors are a specific element associated with 19 work activities, mainly the spreading of manure, animal breeding and plant harvesting. Farmers' working time in conditions of exposure to these factors in the group of plant producers was 51 % of the total working time on average, among animal breeders--80 % and in the case of mixed production--77 %.

Adult↗
PubMedDate not supplied

Immunohistochemical analysis of expression of molecular biologic factors in intraductal papillary-mucinous tumors of pancreas--diagnostic and biologic significance.

BACKGROUND/AIMS: In this study we investigated the expressions of molecular biologic factors, p53, rasp21, bcl-2, c-erbB-2, and Ki-67 by immunohistochemical method in intraductal papillary-mucinous tumor of the pancreas to identify their diagnostic values and to determine their relations to the degree of histopathologic abnormalities. METHODOLOGY: Thirty-eight different histologic lesions from 28 patients of intraductal papillary-mucinous tumor of the pancreas, comprising normal pancreatic duct (n = 6), intraductal papillary hyperplasia (n = 6), intraductal adenoma (n = 15), and intraductal carcinoma (n = 11) were immunostained by the avidin-biotin peroxidase conjugate method. RESULTS: p53 and Ki-67 expressions were significantly greater in malignant intraductal papillary-mucinous tumor than in their benign counterpart (p = < 0.0001), while rasp21 showed gradual increase in the frequency of expression from normal pancreatic duct (0%), to intraductal hyperplasia (16.7%), to intraductal adenoma (26.7%), and ultimately to intraductal carcinoma (63.6%). bcl-2 and c-erbB-2 were not expressed in any lesions. CONCLUSIONS: These results suggest that p53 and Ki-67 expressions have significant diagnostic values in differentiating benign intraductal papillary-mucinous tumors from malignant ones and thus can facilitate in the pre-operative planning of treatment in individual cases. Secondly, gradual stepwise increase in the frequency of rasp21 expression with increasing degree of cellular atypia supports the presence of adenoma-carcinoma sequence in the carcinogenesis of this tumor.

Adenocarcinoma↗
PubMed2000

Borderline personality disorder. Overview of biologic factors.

Exploring the biology of neurotransmitters and polymorphic genes that influence behavior most certainly will increase understanding of the complexity of personality disorders and the people who suffer with them. Continuing biologic exploration of the personality disorders will also provide new and valuable information that will inform and direct ever more sophisticated and specific psychiatric treatments. Further, it will supply knowledge that might begin to erode the strong biases and negative labels that have for too long been applied to these patients. These labels may have been applied not because these patients are bad people, but because of ignorance in understanding their complexity and limited ability to improve their condition. Nonetheless, clinicians must refrain from concluding that the answers to all problems in psychiatric treatment can be answered by the molecular geneticist or biologic researcher. As Reiss et al have written when speaking about nonshared environmental effects and its role in the development of psychopathology: "Psychiatry has been forced into the chronically uncomfortable position of straddling biomedicine and the social sciences and seems always to hunger for relief.... [Yet] the data simply do not permit a conception of the future centered on a straightforward biomedical answer to the fundamental question of the pathogenesis of major disorders. Indeed, a balanced image of the future contains a growing and equal partnership of the social sciences and molecular biology."

Borderline Personality Disorder↗