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R Porschen

Publications and source records attributed to R Porschen.

At least 91 records · Page 5Linked to original sources
PubMed1991

Assessment of proliferative activity in carcinomas of the human alimentary tract by Ki-67 immunostaining.

The monoclonal antibody (MAb) Ki-67, which is directed against a proliferation-associated nuclear antigen, was used to measure tumor proliferation in 165 carcinomas of the esophagus, stomach, colon and rectum with an indirect immunoperoxidase technique. The percentage of Ki-67-positive tumor cells (Ki-67 index) was evaluated with the point-counting method. The Ki-67 index in gastric cancers (mean, 24.8%; standard deviation, 11.1%) was significantly lower than in tumors of the esophagus (35.7 +/- 12.6%), colon (37.6 +/- 15.2%), and rectum (34.3 +/- 16.4%). A wide range of the Ki-67 index (5.9-75.3%) could be observed within the various tumor types. In recurrent colorectal carcinomas, the Ki-67 index significantly increased to 51.9%. The Ki-67 index was independent of pathologic (e.g., TNM-stage, grading, tumor volume, tumor site) and clinical variables (age and gender of the patients). A marked heterogeneity of Ki-67 expression within different tumor stages was noted. Statistically significant regional variations in tumor proliferation existed between different areas within the same tumor.

Adult↗
PubMed1990

[Flow cytometry results in patients with ulcerative colitis and Barrett esophagus. An additional diagnostic tool in the early diagnosis of a malignant transformation?].

In this review the basic principles of flow cytometry for the measurement of DNA content are described. In addition to cell cycle phase distributions DNA ploidy can be analysed by flow cytometry. Flow cytometric results in patients with ulcerative colitis and Barrett's esophagus seem to indicate that besides histologic examinations flow cytometry may play a role in surveillance programs of patients with an increased risk of a malignant transformation. These first interesting results, however, have still to be confirmed in long term studies.

Barrett Esophagus↗
PubMed1989

Assessment of cell proliferation in colorectal carcinomas using the monoclonal antibody Ki-67. Correlation with pathohistologic criteria and influence of irradiation.

Cell proliferation was measured by a three-step immunoperoxidase technique on cryostat sections of 61 resected colorectal adenocarcinomas using the monoclonal antibody Ki-67 that is directed against a proliferation-associated nuclear antigen. The percentage of Ki-67-positive cells was quantified with the point-counting method. The frequency distribution of the percentage of Ki-67-positive tumor cells in 52 unirradiated carcinomas was gaussian with a mean of 38.7% (range, 7.7% to 75.3%). Analysis of the unirradiated tumors showed no relation between Ki-67 staining and various clinicopathologic features including age, sex, tumor volume, tumor differentiation, location, and tumor stage. Although some tumors demonstrated intratumor heterogeneity of immunoreactivity, there was no significant difference in proliferative activity among peripheral, intermediate, and central tumor areas. Whereas the Ki-67 index increased to 47.1% in recurrent carcinomas, it decreased significantly to 24.7% in rectal carcinomas given radiotherapy before surgery. Therefore, Ki-67 immunostaining might be used as a tool to select and monitor patients with colorectal cancers who might benefit from radiotherapy. The marked differences of Ki-67 expression among different tumors may relate to heterogeneity in growth kinetics and may therefore carry prognostic implications.

Aged↗
PubMed1989

Critical evaluation of histochemical and immunochemical methods for the demonstration of vascular supply in rectal and oesophageal cancer.

The vascularisation of rectal and oesophageal carcinomas and of normal mucosa was studied using histochemical and immunohistochemical methods. Endothelial cells were stained for alkaline phosphatase (AP) using an azo-dye procedure. Histochemical results were compared with the immunohistochemical identification of endothelial cells using the monoclonal antibody BW 200 recognising an epitope restricted to human endothelial cells. In the AP experiments the simultaneous reactivity of stromal tissue often precluded the exact evaluation of tumour blood vessels. Immunohistochemistry facilitated the identification of vessels in neoplastic tissues and allowed a quantitative analysis of vascular volume by means of point-counting. Vascular volumes of normal tissues exceeded those of tumours by a factor of 1.6. This immunohistochemical technique has potential application in studying the importance of tumour blood supply in man, especially in relation to radiotherapy.

Antibodies, Monoclonal↗
PubMed1988

In vivo effects of nifedipine and BAY 1 8201 on ceruletide induced gallbladder contraction.

Studies in animals suggest that calcium channel blockers may influence gallbladder contraction. In order to study possible actions in man we examined by ultrasonography the effects of two dihydropyridine derivatives, i.e. nifedipine (20 mg p. o.) and BAY 1 8201 (100 mg p.o.) on ceruletide induced human gallbladder contraction in 9 healthy male volunteers in a randomized, double-blind, three fold crossover study (latin square design). Blood samples for the measurement of plasma drug concentrations were drawn before and at regular intervals up to 8 h after drug ingestion. Ceruletide decreased gallbladder volumes by 52.1 +/- 8.2% (mean +/- 1 SEM) after nifedipine, 53.1 +/- 8.1% after BAY 1 8201 and by 59.3 +/- 10.1% after placebo (NS). Peak plasma concentrations of 53.7 x/: 2.3 ng/ml (geometric mean x/: geometric standard deviation) and of 35.5 x/: 1.5 ng/ml were reached after oral application of nifedipine and BAY 1 8201, respectively. We conclude that human gallbladder contraction in response to ceruletide is not markedly influenced by dihydropyridine derivates in the dosages used in this study. The results reported here stress the importance of calcium released from intracellular stores for the contractility of smooth muscle in the human gallbladder.

Adult↗
PubMed1988

[An experimental study of liver perfusion using non-diffusible radiotracers: differentiation of the arterial and portal venous components by deconvolution analysis of first-pass time-activity curves].

The transfer function of the liver perfusion is an idealized time-activity curve that could be registered over the liver if a non-diffusible tracer would be injected directly into the abdominal aorta and no tracer recirculation would occur. The reproducibility of the transfer function was experimentally investigated in foxhounds. Both the routes of tracer application and the modes of data evaluation were varied and the perfusion was investigated under physiological and pathological conditions. The transfer function was calculated by deconvolution analysis of first-pass time-activity curves using the matrix regularization method. The transfer function showed clearly distinguishable arterial and portal-venous components. Repeated peripheral venous and central aortic applications resulted in reproducible curves. In addition to the arterial and portal-venous components the subcomponents of the portal-venous component could also be identified in the transfer function after ligation of the appropriate vessels. The accuracy of the mathematical procedure was tested by computer simulations. The simulation studies demonstrated also that the matrix regularization technique is suitable for deconvolution analysis of time-activity curves even when they are significantly contaminated by statistical noise. Calculation of the transfer function of liver perfusion and of its quantitative parameters seems thus to be a reliable method for non-invasive investigation of liver hemodynamics under physiological and pathological conditions.

Animals↗
PubMed1987

Age-dependent variation of T1 and T2 relaxation times of adenocarcinoma in mice.

The T1 and T2 values of adenocarcinoma EO 771 inoculated into the hind leg of mice are characterized and correlated with the histopathologic state of the tumor. Growth-dependent changes (indicated by a T1 of 630-910 msec and a T2 of 68-185 msec) can be separated into four characteristic phases. The increase in relaxation times in the early phases (A and B) is due to an increasing amount of viable tumor tissue relative to normal muscle tissue. In the later phases (C and D), a decline of the relaxation parameters is observed that is parallel to an increase in the fraction of necrotic tissue. By multiexponential analysis, two relaxation components (indicated by and, respectively) for T1 and T2 and the corresponding fractions alpha 1 and alpha 2 can be observed for both tumor and surrounding muscle tissue. A tissue criterion ("magnetic resonance fingerprint") is defined by a combination of these multiple parameters. This criterion allows separation of not only muscle and tumor tissue but also viable (early state) and necrotic (late state) tumor tissue.

Adenocarcinoma↗
PubMed1987

Cell loss from viable and necrotic tumor regions after local gamma irradiation measured by 125I-UdR.

Using a tracer technique, loss of cells from perivascular and average tumor cells of the syngeneic mammary adenocarcinoma EO 771 in male C57Bl/6J mice may be measured in the living animal, by the use of 125-labelled 5-iodo-2'-deoxyuridine (125I-UdR). It was the purpose of this paper to compare measurements in vivo with those made in vitro following local 60Co-gamma irradiation in the absorbed dose range from 10 to 27.5 Gy, incorporation of radioactivity into DNA of tumor cells and activity loss from labelled tumor cells were measured externally by a special scintillation counter device. In addition, by injecting the vital dye "light green" into the mice the I-125-activity of the stained viable and unstained necrotic regions were separately measured for loss of activity following gamma irradiation. A comparison was made between radiation induced growth delay and the depression of 125I-UdR incorporation into DNA of the proliferating tumor cells. After local tumor irradiation with a dose of 27.5 Gy 60Co gamma rays an enhancement of the activity loss by 0.5% per hour was externally observed for the perivascular tumor cell population. A lower enhancement of 0.4% per hour was externally registered in the average tumor cell population. Both values were evaluated relative to sham-irradiated control tumors. The measurements on isolated tumors were in comparatively good agreement with the external values. The activity loss rate from the viable, euoxic tissue increased by 0.4% per hour after 27.5 Gy 60Co gamma rays and by 0.3% per hour in the average cell population, the latter representing a mixture of euoxic and hypoxic cells. The results demonstrate, that the external measurements are a good indicator for radiation effects under in vivo-conditions.

Adenocarcinoma↗
PubMed1987

Reutilization of 125I-UdR during growth of a solid mammary carcinoma: implications for the 125I-UdR loss technique.

Reutilization of thymidine (TdR) and 5-iodo-2'-deoxyuridine (I-UdR) released by dying tumour cells was assayed in the syngeneic adenocarcinoma EO 771 by injecting heat killed, labelled tumour cells into tumours. 3H and 125I liberation from labelled breakdown products was measured in tumours of various sizes without or with separation of tumours into viable and necrotic portions. Internal reutilization of 3H-TdR was considerably greater than that of 125I-UdR. 125I-UdR released by dying tumour cells was reutilized at about 10%. There was no significant increase in 125I-UdR reutilization during tumour growth. It is concluded that measurements of radioactivity loss by the 125I-UdR technique can result in underestimating the real cell loss depending on the amount of internal reutilization by the tumours investigated. Compared with 3H-TdR 125I-UdR is the tracer of choice for long term studies of cell loss.

Adenocarcinoma↗
PubMed1986

[Hemorrhagic colitis as a sequela of a soap enema--case report].

The case of a 45 year old man is reported who developed an acute hemorrhagic colitis after the administration of a soapsud enema. Clinical, laboratory, radiologic, endoscopic and histologic findings are presented and compared with reports from the literature. Differential diagnosis of soap colitis has to include ischemic and drug-induced colitis. Because of the possible complication soapsud enemas should not be used any longer in medical practice.

Colitis↗
PubMed1986

17-Iodine-123 iodoheptadecanoic acid for metabolic liver studies in humans.

(17-123I)-Iodoheptadecanoic acid ([123I]HA) was used for dynamic planar scintigraphy of the liver in normal individuals (control I), in patients without liver disease but with elevated serum cholesterol and/or triglycerides (control II), and in patient groups with alcohol-induced fatty liver (PG I), fatty liver not due to alcohol (PG II), alcohol-induced liver cirrhosis (PG III), or liver cirrhosis of the posthepatitic type (PG IV). Tracer uptake and elimination time were assayed in different liver regions; mean elimination time was expressed for total liver. In control I, tracer uptake was homogeneous, and mean elimination time was 20.7 +/- 5.3 min without significant local variations. In control II, tracer uptake was reduced but homogeneous and mean elimination time was 59.4 +/- 35.8 min with some local variations. In PG I, uptake was reduced and inhomogeneous and elimination time was the same as in control I, irrespective of cholesterol and triglyceride values. In PG II, uptake was the same as in PG I but mean elimination time was 48 +/- 8.1 min with some local variations. In PG III, uptake was extremely reduced and spotty and elimination time correlated with the severity of disease from 19 to 881 min in different liver regions.

Fatty Acids↗
PubMed1985

Evaluation of radio- and chemotoxic effects of 125I-UdR on tumour growth and host survival.

The toxicity of 5-iodo-2'-deoxyuridine (I-UdR) was assayed in male C57 BL/6J mice bearing the syngeneic mammary adenocarcinoma EO 771 by injecting different doses of 'cold' I-UdR or 125-iodine labelled I-UdR. Host survival, tumour growth, DNA-precursor incorporation, whole-body retention and tumour activity loss rates were chosen as biological end points. There was no measurable effect on host survival up to doses of 5 micrograms I-UdR or 50 microCi 125I-UdR per mouse during a mean life-span of 25 days. Adjusted to a constant amount of 0.55 micrograms I-UdR/mouse, radiotoxicity of 125I-UdR on tumour growth (up to 17 days after implantation), tracer incorporation, whole-body and tumour retention (up to 12 days after 125I-UdR injection) could be excluded up to a dosage of 50 microCi 125I-UdR/mouse. It is concluded that in situ evaluation of tumour activity loss rates in carcinoma EO 771 is not disturbed by toxic effects of I-UdR or 125I-UdR within the dose limits mentioned.

Adenocarcinoma↗
PubMed1985

[Differential diagnosis of cystic intra-abdominal lesions: mucocele of the appendix].

The sonographic appearance of a mucocele of the appendix in a 69-year-old woman is presented. The mucocele showed an atypical localisation in the right upper quadrant just below the gallbladder. This own observation is compared with other case reports in the literature. The value of ultrasound examinations in the diagnosis "mucocele of the appendix" is discussed.

Aged↗
PubMed1983

Cell loss from viable and necrotic tumour regions measured by 125I-UdR.

Loss of cells from vital and necrotic areas of the syngeneic mammary adenocarcinoma EO 771 in male C57 BL/6J mice may be measured by use of 125I-labelled 5-iodo-2'-deoxyuridine (125I-UdR). Later than 50 hr after an intraperitoneal injection of 20 muCi 125I-UdR the incorporated activity of the entire tumour was externally measured and found to decrease with time after injection. The injected amount was neither chemo- nor radiotoxic. By injecting the vital dye 'light green', unstained necrotic and stained viable regions were separately excised and measured for loss of activity throughout the natural development of the labelled tumour. With the appearance of necrotic regions, labelled viable cells became necrotic, and activity was slowly eliminated. With increasing proportions of necrosis during tumour growth, the rate of loss of activity of the whole tumour decreased. Loss of activity from viable tumour regions reflected cell death and exceeded the loss rates of the whole tumour by a factor of 2 to 3. The data show that loss of activity from the whole tumour results from a superposition of different elimination rates of viable and necrotic tumour regions and is not an immediate consequence of cell death in the course of undisturbed tumour development.

Adenocarcinoma↗