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Biomedical subjects

A L Pohl

Publications and source records attributed to A L Pohl.

11 recordsLinked to original sources
PubMed1993

Evaluation of laboratory data by conventional statistics and by three types of neural networks.

Sixty-three patients with lung (34 small-cell, 18 squamous, 11 adeno-) carcinomas and 43 patients with benign lung diseases were characterized with seven tumor markers: neuron-specific enolase (NSE); cancer antigens CA 19-9, CA 125, CA 15-3, and CA 50; carcinoembryonic antigen (CEA); and tissue polypeptide antigen. Diagnosis had been established by histological examination after surgery and used for classification. After vector transformation, the tumor marker data were fed into neural networks (NNs) based on three different types of learning algorithms: backpropagation (BP), competitive learning (CL), and Hopfield (H). For comparison, the data were evaluated with multivariate stepwise discriminant analysis (MVSDA). BP-NNs are equal to (NSE, CA 19-9, CEA) or better than (100% correct classification when using all seven markers) MVSDA in assigning the correct diagnosis to the patients. Cross-validation data yielded shrinkage effects ranging from 0% to 12.5%. Quality-control (QC) data were evaluated by traditional QC algorithms and compared with the results obtained by a BP-NN. The results show that the BP-NNs could only partly fulfill the tasks of three QC algorithms regarding the violation of static borders but gave good results with respect to dynamic changes.

Biomarkers, Tumor↗
PubMed1985

Enzyme activities in human breast tumor cells and sera.

Galactosyltransferase (GalTF), sialyltransferase (SiaTF), fucosyltransferase (FucTF), 5'-nucleotidase (5'Nucl), and ADP-ribosyltransferase (RibTF) were determined in three subcellular fractions of tumor cells and adjacent control tissue from 20 patients with small primary infiltrating ductal adenocarcinomas of the breast. Viable, as pure tumor cell populations as possible were isolated, subfractionated, and their enzyme levels compared to those in the patients' sera. The activities in tumor cells of the three glycosyltransferases were two- to seven-fold higher, whereas 5'-Nucl and RibTF showed reduced activities when compared to adjacent noninvolved tissue. Serum GalTF and SiaTF were slightly elevated in early mammary carcinoma, whereas FucTF, 5'Nucl, and RibTF were decreased in comparison with a control group. The proposed tumor origin of circulating enzymes could not be confirmed. Surprisingly, only for RibTF could a correlation between tumor and serum activity be established; a weak correlation was found for SiaTF. However, no such relationship could be determined for GalTF, FucTF, or 5'Nucl. In conclusion, the enzyme profile of the tumor cell does not, except for RibTF, appear in the serum. Serum enzyme profiles, therefore, do not permit detection of the early stages of breast cancer. A high correlation between RibTF activity and cytosol estrogen and progesterone receptor levels has been determined in tumor cells, possibly indicating slower growing, more differentiated types of breast tumors.

5'-Nucleotidase↗
PubMed1984

Critical comments on galactosyltransferase.

Galactosyltransferase (GT) is reported to be a good marker for a number of malignancies. Analytical and preparative attempts to characterize the more specific tumor-associated GT II variant did not yield the expected improved applicability in routine clinical testing for cancer. They indicated instead a puzzling heterogeneity of GT and a special relationship between serum-GT forms and acceptorlike serum glycoproteins. These adducts may represent a general host response to malignant transformation and some nonmalignant events as well. The assay for GT II is, at present, too laborious and time consuming and not readily reproducible. From an extensive discussion of the problems and pitfalls of the GT assay and physiological variation of GT it is concluded that the test is of interest mainly for research purposes and cannot actually serve in the care of patients.

Carbohydrates↗
PubMed1982

Neurofibroma of the ear: function and aesthetics.

The cutaneous stigmata of neurofibromatosis can be significantly deforming and a source of great anguish. The disease has no cure. Excision of an auricular neurofibroma in a middle-aged man removed an occlusive mass in the ear canal. A suspension of the ear was performed using a strip of Marlex mesh. This technique may offer a more lasting result than autogenous grafts.

Ear Neoplasms↗
PubMed1976

Thumb reconstruction in the severely burned hand.

The standard techniques have generally been adequate for thumb reconstruction in the severely burned hand. The basic principles of preservation of length, prevention of malposition and contracture by appropriate splinting, early motion, and early skin coverage are all applicable. The nature of the tissue changes wrought by the burn wound, however, frequently necessitates certain modifications in the approach to surgical reconstruction. We have described these and our methods used in handling 9 specific cases.

Adolescent↗
PubMedDate not supplied

A new ADP-ribosyltransferase in human serum: significance in cancer.

A novel ADP-ribosyltransferase (ADPRT) is reported from sera of both healthy human subjects (n = 25) and patients with colorectal tumors (n = 12) and breast cancer (n = 55). In sera of healthy controls (n = 25) the average ADPRT values were 250 +/- 56 picokatal/liter. ADPRT serum activities in metastatic cancer patients (n = 47) were three times higher (p less than 0.01) than in normal controls. A tumor origin of the serum ADPRT can be inferred from the statistical correlation (R = 0.74) between tumor and serum levels. The radiometric test procedure (CV 20-25%) is critically validated and kinetic properties of serum ADPRT have been studied, showing a competitive inhibition by nicotinamide, benzamide and 3-aminobenzamide. The kinetic parameters of serum ADPRT resemble those reported for nuclear ADPRT, thus indicating that serum ADPRT activity could be due to a nuclear enzyme released from the tumor cells.

Breast Neoplasms↗