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Biomedical subjects

M Oberholzer

Publications and source records attributed to M Oberholzer.

At least 91 records · Page 5Linked to original sources
PubMed1984

Electron microscopy as a tool in the diagnosis of endocrine tumors.

Electron microscopy (EM) has provided a large amount of information toward the discovery of endocrine cell systems and the analysis of endocrine tumors. In the diagnosis of endocrine tumors EM is most often not decisive. This is due to sampling errors, tumor cell diversity, pleomorphism of cellular organelles, particularly of secretory granules, and to the lack of reliable structural markers of biologic behaviour of tumor cells. For diagnostic purposes EM has been superseded by immunocytochemical techniques, and in the near future recombinant DNA technology will probably lead to further progress in the precision of analysis of hormone production by tissues, cells and tumors. On the other hand, EM combined with other techniques is a powerful tool in research.

Adenoma↗
PubMed1984

Do's and don'ts in stereological pathology or possibilities of stereological-biochemical correlation in uropathology.

The problems and the interpretation of combined stereological-biochemical investigations in benign prostatic hyperplasia (BPH) research are discussed. As BPH is characterized by a primary stromal enlargement the role of the smooth muscle cell (SMC) is focussed. For determination of the single cell volume of the SMC several methods are applicable leading to different results. Thus interpretation of these results has to be done with caution. Finally as an example there is a discussion of a correlation of stereological-biochemical dates of human prostatic tissue samples.

Adult↗
PubMed1984

Morphometry in endocrine pathology.

The most important purposes of morphometry in endocrine pathology are described. With the introduction of immunocytochemical techniques by Sternberger in 1969 a new field for detailed morphometric analysis in endocrine pathology was opened. The application of morphometry in combination with the immunocytochemical staining of cells is illustrated by studies of the role of gastrin and gastric secretion in the etiology of duodenal ulcer. For such studies morphologic alterations have to be quantified. Morphometry as an instrument for characterizing diseases has been used in various fields, e.g. to analyse nesidioblastosis, diabetes mellitus or papillary carcinomas of the thyroid gland.

Duodenal Ulcer↗
PubMed1983

Bone marrow cell dose and kinetics of recovery following allogeneic marrow transplantation in man.

In 50 patients transplanted for acute or chronic leukemia we studied the correlation between the number of infused bone marrow cells/kg recipient body weight and the time needed for engraftment. Engraftment was arbitrarily defined as the first day of 1 X 10(9) leukocytes/l and of 20 X 10(9) reticulocytes/l after the posttransplantation nadir. There is a negative non-linear correlation between the duration of leukopenia following marrow transplantation and the amount of transfused nucleated cells (p = 0.01). Since the incidence of infectious or hemorrhagic complications depends directly on the duration of aplasia it is justifiable to give a maximal cell dose.

Acute Disease↗
PubMed1983

Influence of age on pulmonary haemodynamics at rest and during supine exercise.

To determine the effects of age on the pulmonary circulation at rest and on exercise we analysed the results of right heart catheterization studies performed in 125 asymptomatic subjects aged 14-68 years, who were healthy or had indispositions which did not impair cardiac or pulmonary function. Age accounted for less than 10% of total variation in resting values of right atrial, pulmonary artery and wedge pressures, and of cardiac output. The pulmonary artery-wedge pressure gradient and flow resistance at rest significantly increased with age. On exercise there were significant increases with age in right atrial, pulmonary artery and wedge pressures, pulmonary to wedge pressure gradient and flow resistance, but cardiac output was not influenced by age. Pulmonary circulation variables at rest are mainly influenced by sex and size, but during exercise significant effects of age are apparent.

Adolescent↗
PubMed1983

Minimum sample size of kidney biopsies for semiquantitative and quantitative evaluation.

The minimum sample size for semiquantitative and quantitative evaluation of interstitial tubular and glomerular parameters is calculated. For the majority of parameters a renal cortex area of 2 mm2 or 7 glomeruli (adults) or 13 glomeruli (children) is sufficient. Larger biopsies or more glomeruli are necessary for the evaluation of the area density of interstitium patent and obsolescent glomeruli as well as the numerical density of obsolescent glomeruli. The most sensitive parameters are those concerning crescents which require biopsies of 11-19 glomeruli in adults and 40 glomeruli in children. In summary, biopsies of usual size (10 mm2) containing about 20 glomeruli are sufficient for qualitative and quantitative evaluation.

Adolescent↗
PubMed1983

[How reliable is cancer diagnosis with needle biopsy of the prostate?].

Aim of the study was to investigate the reproducibility and the reliability of the morphological diagnosis, of different morphological parameters and representativity of needle biopsy material compared with transurethral resection material. 416 needle biopsies of carcinomas of the prostate were studied by 5 pathologists. 130 biopsies were evaluated twice by the same investigators and 325 at least by one other investigator. In 65 cases, tissue obtained by transurethral resection was evaluated by the same investigator who had seen the biopsy. The diagnosis of carcinoma of the prostate was highly reproducible, only in 2% of the cases the original diagnosis was not confirmed; 5 out of 27 systematically evaluated parameters proved to be very reliable and reproducible, i.e. histological tumor classification, cribriform glands, invasion of perineural spaces, nucleoles, nuclear polymorphism, 8 parameters were sufficiently reproducible and 14 were unreliable among which cytologic differentiation was one. The diagnostic reproducibility between biopsy material and transurethral resection material was only 48.8%. This very low figure can be explained by the marked histologic heterogeneity of the tumors of which only 13% were classified as uniform carcinomas. The conclusions of the investigation are: 1. The diagnosis carcinoma is highly reliable and reproducible in needle biopsies. 2. Needle biopsy tissue is not representative for the entire tumor. 3. Grading of prostate carcinoma is highly subjective and therefore no sound basis for therapy and prognosis in the individual patient.

Biopsy, Needle↗
PubMed1982

A concept for breath by breath computing of lung compliance in the ventilated patient.

A concept for calculating dynamic lung compliance (CL) by computer in ventilated supine patients is described. The primary signals are gas flow, airway pressure, esophageal pressure (PES) and ECG. Endinspiratory and endexpiratory PES is calculated as a mean value during an R/R interval's time just before the end of inspiration and expiration. Its main advantage is a reduction of the variability in computer calculated CL by reducing the influence of cardiac oscilliations on PES tracings, thus enabling evaluation of special ventilatory settings as intermittent mandatory ventilation or rapidly changing PEEP.

Computers↗
PubMed1981

Massive ovarian oedema with production of testosterone.

Clinical, biochemical, light- and electron microscopic, and immunocytochemical findings of a 13 1/2 year old girl with delayed menarche and signs of virilization due to massive oedema of the left ovary with activation of stromal cells (hyperthecosis) are presented. Testosterone and oestradiol production by large cells in the voluminous ovary was demonstrated by immunocytochemistry and radioimmunoassay. Massive ovarian oedema may result from partial or intermittent torsion of the mesovary interfering with venous and lymphatic drainage, but not with arterial blood flow.

Adolescent↗