Search PubMed⌕ Search

Biomedical subjects

J Kern

Publications and source records attributed to J Kern.

At least 91 records · Page 5Linked to original sources
PubMed1993

Medical decision making based on inductive learning method.

Medical decision making based on inductive learning has been studied in order to collect experience necessary for practical use of such methods in clinical and epidemiological work. The decision trees have been constructed by using the modified Quinlan's approach based on choosing relevant attributes according to their informativity. An inductive learning software tool, ASSISTANT Professional, has been used for experimenting. The variability in results has been studied under varying learning conditions. Two sets of data have been chosen for learning experiments: from a study on rheumatoid factors in patients with rheumatoid arthritis, and from an epidemiological investigation of aging. The results of this study indicate the necessity to determine inductive learning parameters for each particular problem. The pruning procedure is always recommended as it eliminates redundant elements in the tree. In problems with greater number of attributes, however, pruning itself is not guaranteeing satisfactory solutions. Interventions like the change of the minimal weight threshold might improve the situation. If these precautions are met, the method of inductive learning seems to be a useful guide in practical clinical and epidemiological decisions.

Aging↗
PubMed1993

Analysis of data as information: quality assurance approach.

Describes a prototype module for data analysis of the healthcare delivery system. It consists of three main parts: data/variable selection; algorithms for the analysis of quantitative and qualitative changes in the system; and interpretation and explanation of the results. Such a module designed for primary health care has been installed on a PC in the health manager's office. Data enter the information system through the standard DBMS procedures, followed by calculating a number of different indicators and the time series, as the ordered sequences of indicators, according to demands of the manager. The last procedure is "the change analysis" with estimation of unexpected differences between and within some units, e.g. health-care teams, as well as some unexpected variabilities and trends. As an example, presents and discusses the diagnostic pattern of neurotic cases, referral patterns and preventive behaviour of GP's teams as well.

Croatia↗
PubMed1993

[Immunologic reactions, respiratory symptoms and ventilatory capacity in jute and sisal textile workers].

Allergic reactions in relation to respiratory symptoms and ventilatory capacity were studied in 41 textile workers employed in the processing of jute and sisal. Only 5.0% of the jute workers and 9.5% of the sisal workers demonstrated positive skin reactions to jute or sisal allergens. Increased IgE was found in 9.8% of the textile workers. Among 35 control workers 11.4% reacted with a positive skin reaction to the jute or sisal allergen and 2.9% had increased IgE. Chronic respiratory symptoms as well as changes in ventilatory capacity were found in textile workers with positive and negative skin tests. Our data suggest that immunological reactions are not likely to be responsible for the development of respiratory impairment in textile workers exposed to jute and sisal dust.

Adult↗
PubMed1992

Respiratory symptoms and ventilatory capacity in swine confinement workers.

A group of 59 workers (41 men and 18 women) employed in swine confinement areas was studied to assess the presence of acute and chronic respiratory symptoms and the prevalence of abnormalities in ventilatory function. A control group of 46 (31 men and 15 women) unexposed workers was studied for the prevalence of chronic respiratory symptoms. For both male and female swine confinement workers complaints of chronic cough, dyspnoea, and chest tightness were significantly more frequent than among control workers. Male workers also complained more of chronic phlegm. Male swine confinement workers who were smokers had significantly higher prevalences of chronic cough, chronic phlegm, and chronic bronchitis than male non-smoking swine confinement workers. The frequency of acute symptoms associated with the workshift was high among the swine confinement workers with more than half of the workers complaining of cough and dyspnoea associated with work. Significant acute across shift reductions in lung function occurred in swine confinement workers, being largest for FEF25. All Monday preshift ventilatory capacity measurements in male confinement workers were significantly lower than predicted values; FVC and FEV1 were found to be lower than predicted values for women. The data indicate that exposure in swine confinement buildings is associated with the development of acute and chronic respiratory symptoms and impairment of lung function. Smoking appears to aggravate these changes.

Acute Disease↗
PubMed1992

[Monitoring of respiratory symptoms and pulmonary ventilatory function in sisal processing workers].

The prevalence of acute and chronic respiratory symptoms and ventilatory capacity was studied in 50 textile workers exposed to sisal dust. A follow-up study was performed 19 years later and included 20 workers out of the 50. The first study showed a considerably higher prevalence of all chronic respiratory symptoms in the exposed than in control workers although the difference was statistically significant only for chest tightness (P < 0.01). Comparison of the prevalence in the first and the follow-up study in 20 textile workers revealed a statistically significant increase in the rate of chronic cough, dyspnea, chest tightness and nasal catarrh. During the follow-up study the prevalence of almost all chronic respiratory symptoms was significantly higher in exposed than in control workers. Results of ventilatory capacity in 50 sisal workers showed acute reductions of FVC and FEV1 during work shift on Monday and the following Thursday. Comparison of the measured and predicted normal values demonstrated lower values in the follow-up study in comparison to those in the first study. The mean annual fall of ventilatory capacity tests was 0.027 L for FVC and 0.036 L for FEV1. Data suggest that long-term exposure to sisal dust may cause the development of chronic respiratory symptoms and lung function impairment in sensitive subjects.

Adolescent↗
PubMed1992

[Respiratory symptoms and pulmonary ventilating capacity in professional drivers and mechanics].

The prevalence of respiratory symptoms and ventilatory capacity were studied in 116 drives and 119 mechanics. The drivers and mechanics demonstrated a significantly higher prevalence of most chronic respiratory symptoms than control workers. Among drivers smokers there was a significantly higher prevalence of most chronic respiratory symptoms than among non-smoking drivers. Drivers and mechanics with more than 10 years of service also showed a higher prevalence of respiratory symptoms than those employed for less than 10 years. A certain number of subjects complained of acute symptoms during work shift. All ventilatory capacity tests, particularly FEF25, demonstrated lower values in comparison to predicted normal values. Our data for drivers and mechanics indicate that long-term employment, particularly in combination with smoking, may cause the development of respiratory symptoms and changes in lung function.

Adult↗
PubMed1991

[Immunologic findings and ventilatory function in cotton industry workers].

Immunological testing was carried out in 24 cotton workers and in 30 control workers. Skin prick test was performed with allergens prepared from cotton dust and cotton seed. Skin tests were positive in 33.3% and IgE level was increased in 62.5% of the cotton workers. Only two 3.3% had positive skin tests and none had increased IgE serum level. Ventilatory capacity in cotton workers with positive skin tests and those with negative skin tests was comparable. The same was true of the workers with increased and normal IgE levels. The effect of cotton dust extract on isolated tracheal smooth muscle of a guinea pig was an indication of a direct irritative action causing airway obstruction.

Adult↗
PubMed1990

A longitudinal study of the relationships among alcohol use, marijuana/hashish use, cocaine use, and emotional/psychological functioning problems in a cohort of high-risk youths.

There is increasing recognition that children involved in the justice system often have serious, multiple problems in the areas of physical abuse, sexual exploitation, and alcohol/other drug use (ADM). Using data collected in a longitudinal study of detained juveniles, we test a model of the relationships of these problems. Significant over-time interrelationships are found among these problems. Research and policy implications of these important findings are drawn.

Adolescent↗
PubMed1990

Regulation of stability and synthesis of EGF-receptor mRNAs encoding for intact and truncated receptor forms.

The EGF-receptor is a proto-oncogene encoded membrane protein related to the v-erb-B oncogene product of avian erythroblastosis virus. Here we have studied the expression and stability characteristics of two forms of receptor mRNA--a 5.6 kb form that encodes for the intact transmembrane 170 kDa receptor and a 3' deleted 2.6 kb form that encodes for a 100 kDa secreted EGF-receptor. In previous studies we showed that EGF increased the synthesis of its own receptor in human cytotrophoblasts and A431 cells. Now we show that EGF stimulates the transcription of the receptor gene and blocks the degradation of transcripts, and thus elevates the level of receptor mRNA in these cells. To test the role of prior protein synthesis in these phenomena, we examined the effect of cycloheximide, and found that this reagent, either alone or in combination with EGF, leads to an increase in the level of EGF-receptor mRNA. Increases were seen in both size classes of receptor mRNA. Further analysis showed that cycloheximide enhances both synthesis and stability of receptor mRNA. While the intrinsic stability of the 3'-truncated 2.6 kb mRNA is approximately 2-fold higher than that of the 5.6 kb species, it is enhanced by more than 10-fold in the presence of cycloheximide and EGF acting in a synergistic manner. The extent of stabilization was less for the larger mRNA form. The results suggest the involvement of ligand as well as labile proteins in the control of synthesis and stability of EGF-receptor mRNA, and imply the involvement of 3' located structural features in the control of receptor mRNA stability.

Blotting, Northern↗
PubMed1989

Production of interleukin 1 activity by cultured human melanoma cells.

A panel of melanoma cell lines derived from 7 primary and 20 metastatic lesions was tested for the production of interleukin 1 (IL-1) in standard mouse thymocyte costimulation assays. Constitutively produced IL-1 activity was found in the conditioned media of 4 of 7 primary and 5 of 20 metastatic melanoma cell lines tested. Four of 9 cell lines secreting IL-1 were also shown to contain cell-associated activity in their lysates. Melanoma-conditioned media were, however, unable to support the growth of CTLL, an interleukin 2-dependent cell line. The secreted IL-1 activity was significantly inhibited by antibodies to recombinant IL-1 alpha (3 of 3 lines), but not antibody to recombinant IL-1 beta. When conditioned medium from one cell line was fractionated on a Superose 12 column by fast protein liquid chromatography, a major peak of activity eluted at Mr 22,500-27,500. The presence of 2.2-kilobase mRNA hybridizing a probe for IL-1 alpha and 1.6-kilobase mRNA hybridizing a probe for IL-1 beta was detected by Northern blot in 3 of 4 secreting cell lines but not in a nonsecreting line. Taken together, these results suggest that cultured melanoma cells produce the cytokine IL-1 alpha, although the relationship between melanoma IL-1 and monocyte IL-1 is unclear. The production of IL-1 by melanoma cells is of interest because of its potential roles in the biology of melanoma through direct effects on tumor growth or through indirect effects on adjacent stromal and endothelial cells and infiltrating lymphoid cells.

Antibodies, Monoclonal↗
PubMed1989

Differentiating pancreatic pseudocyst and pancreatic necrosis using computerized tomography.

Ten per cent of patients with acute pancreatitis will develop pancreatic complications. Differentiating pancreatic pseudocyst formation from pancreatic necrosis may be difficult based on clinical grounds. The purpose of this study was to evaluate the role of computerized tomography in differentiating these processes. A retrospective analysis was performed of 40 patients who developed pancreatic complications following an episode of acute pancreatitis and who subsequently underwent operation for drainage of their pancreatic fluid collections. All 40 patients had abdominal CT scans performed before surgery and the patients were then categorized on the basis of CT findings as having (1) a pseudocyst with a well-defined cyst wall, (2) peripancreatic fluid marked by the absence of a cyst wall, and (3) a combination of a pseudocyst as well as free peripancreatic fluid. Patients with pseudocysts had an average hospital stay of 14 +/- 2 days, a hospital morbidity rate of 16%, and a hospital mortality rate of 0%. In contrast, patients with peripancreatic fluid collections had an average hospital stay of 43 +/- 4 days (p less than 0.01) and hospital morbidity and mortality rates of 74% (p less than 0.01) and 22% (p less than 0.05), respectively. Patients with both pseudocysts and peripancreatic fluid collections behaved in a similar fashion to patients with peripancreatic fluid alone as characterized by a prolonged hospital stay and a high incidence (80%) of postoperative complications. At one year follow-up, 89% of the patients with pseudocysts were asymptomatic, whereas only 13% (p less than 0.01) of patients with peripancreatic fluid were symptom free. These data demonstrate that pseudocyst and peripancreatic fluid collections have markedly different biologic characteristics both in their short-term and long-term behavior. The results suggest that CT scanning can differentiate these processes and may help in directing the appropriate surgical therapy.

Acute Disease↗
PubMed1988

Effects of local chemotherapy and immunotherapy on the recurrence and progression of superficial bladder cancer.

409 cases of superficial bladder carcinoma (pTa, pTi, Tis) are reported. They are divided into three groups: 171 patients treated by TUR alone, 124 treated by TUR and local thio-TEPA, and 114 patients treated by TUR and BCG vaccine locally. It was found that the frequency of recurrence fell by 56.7, 41.9 and 26.3%, while the progression of the illness declined correspondingly by 19.8, 16.9 and 11.4%. In other words, in terms of recurrence and progression, the poorest results were found for the group treated by TUR only, and the best results were found with the TUR and BCG group.

Administration, Intravesical↗