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Biomedical subjects

A O Myking

Publications and source records attributed to A O Myking.

At least 19 recordsLinked to original sources
PubMed1992

Differentiated thyroid carcinomas: the relevance of various pathological features for tumour classification and prediction of tumour progress.

In this series of 263 surgically treated cases of thyroid cancer, 12% were finally classified as benign lesions after histopathological review. Difficulty in the assessment of tumour capsule invasion in follicular neoplasms was the most frequent cause of diagnostic error. Squamous metaplasia, clusters of ground glass nuclei and psammoma bodies were found to be the most specific discriminators between papillary and follicular carcinomas. Among papillary carcinomas, tumour diameter above 30 mm, thyroid capsular invasion and regional lymph node metastases were found to be significant prognostic factors according to survival analyses. Of additional practical importance, our results indicate that tumour infiltration in the thyroid capsule should be reported as a marker of early extra-thyroidal extension.

Adenocarcinoma↗
PubMed1992

Prognostic importance of various clinicopathological features in papillary thyroid carcinoma.

The influence of various pathological features on tumour recurrences and cancer deaths has been studied in 173 consecutive cases of surgically treated papillary thyroid carcinoma recorded in 1971-1985. During the follow-up (median 7.3 years), 18.6% of the 161 radically treated patients had recurrent disease, and 8.7% died of thyroid cancer. In the univariate life-table analysis, recurrence-free survival was significantly related to age, pTNM category, tumour size, presence of certain growth patterns, tumour necrosis, tumour infiltration in surrounding thyroid tissue and thyroid gland capsule, lymph node metastases, presence of extra-nodal tumour growth and number of positive lymph nodes, whereas only tumour diameter, thyroid gland capsular infiltration and presence of extra-nodal tumour growth remained as significant prognostic factors in the multivariate analysis. Regarding thyroid cancer deaths, sex, age, pTNM category, radicality of surgical treatment, tumour diameter, macroscopic appearance, cellular atypia, tumour necrosis, thyroid gland capsular infiltration, vascular invasion, extra-thyroidal extension and lymph node metastases were all significant variables in the univariate analysis. However, only sex, age, radicality of surgical treatment and vascular invasion were found to be significant predictors of thyroid cancer deaths in the final multivariate Cox model, whereas cellular atypia and necrosis showed a borderline significance. Our study thus documents the independent importance of certain histological features for morbidity and mortality in surgically treated cases of papillary thyroid cancer.

Adolescent↗
PubMed1990

Increased content of chromium and nickel in lung tissues from patients with bronchial carcinoma.

Epidemiological studies have shown that occupational exposure to certain chromium and nickel compounds is followed by an increased lung cancer incidence. However, few data exist on the content of these metals in lung cancer patients in general. In the present study, central and peripheral lung tissue, bronchial tissue and hilar lymph nodes were collected from 20 patients with bronchial carcinoma and 21 control individuals, and the tissue concentration of chromium and nickel was measured by use of atomic absorption analysis. Increased levels of both metals were found in cancer patients as compared to controls. Lung tissue concentration of chromium was two-fold increased, while the bronchial wall content of nickel was three times the level in control individuals. Smokers showed a dose-related increase in the deposition of both chromium and nickel. Furthermore, in cancer patients an inverse relationship between smoking and the tissue level of chromium in regional lymph nodes was found, possibly indicating a depressive effect on pulmonary clearance mechanisms. Our results emphasize the possible role of small amounts of chromium and nickel as agents in bronchial carcinogenesis, unrelated to occupation and probably related to tobacco smoking.

Adult↗
PubMed1989

[Fine needle aspiration cytology of the breast. A simple method?].

During the period 1981-85, 3,743 fine-needle aspiration cytologies of breast tissue from 3,188 patients were reported by the Gade Institute, Department of pathology. Subsequent histologic examination was performed in the case of 798 patients. Among 421 histologically proven carcinomas after previous fine-needle aspiration, there were no false positive and 13 false negative cytological diagnoses. The specificity was 100% and, depending on the criteria used, the sensitivity 77.9 or 96.4%. Altogether 223 doctors performed the aspirations. This high number was probably the main reason for an unacceptably high proportion of inadequate smears. In experienced hands the proportion of inadequate smears was less than 4-7% in patients with carcinomas.

Adult↗
PubMed1989

Analyses of chromium and nickel in human pulmonary tissue. Investigations in lung cancer patients and a control population under special consideration of medical expertise aspects.

After inhalative occupational exposure to certain compounds containing nickel and chromium (mostly over many years), an accumulation of these metals may occur in the lung tissue. This is of particular importance, both from a toxicological point of view and with regard to expert reports, since certain nickel and chromium compounds may induce lung cancers. In the context of this study, samples of pulmonary tissue from 34 deceased persons from the Bergen area (Norway) were analysed by atomic absorption spectrometry with regard to their content of chromium and nickel. The deceased comprised 21 men and 13 women. In 15 cases, death resulted from lung cancer; in the other 19 deceased, there was no indication of a malignant disease of the airways. The concentrations of nickel found in the lung tissue do not differ between patients with lung cancer and patients with healthy lungs. On the other hand, the concentration of chromium in the pulmonary tissue in the patients who had died of lung cancer and who had all been inhalative smokers, are higher (statistically significant) than in the nonsmokers or in those with healthy lungs. An accumulation of these two metals in the tumor matrix could not be detected. Both the average nickel and the average chromium concentrations were higher in the persons who had probably been exposed occupationally. Considering the present state of scientific knowledge, the aspects relevant to expert reports which result from the analyses of metals in the pulmonary tissue are discussed.

Adult↗
PubMed1989

Balloon cell melanoma mimicking clear cell carcinoma.

Balloon cells may occur in both benign nevi and malignant melanomas. Sometimes they dominate the histological appearance and cause difficulties in biopsy interpretation. There are no specific clinical characteristics. We report a metastatic balloon cell melanoma where the primary tumour was not identified and the histological appearance mimicked that of a clear cell renal carcinoma.

Adenocarcinoma↗
PubMed1979

Responses of the thymus and the paracortex of draining lymph nodes to repeated applications of oxazolone to mouse skin.

The oxazolone-induced response in the paracortex of draining lymph nodes is characterized by an early increase in the proliferative activity that decreases to control levels when stimulation is continued. The possibility that this may be a toxic side effect of the concentrated oxazolone solution used was investigated by simultaneous registration of the changes taking place in the thymus. These were found to be different from toxin-induced changes and compatible with cell loss due to massive emigration of cells. Repopulation of the thymus took place over the last 1 1/2 week of stimulation. It was concluded that the changes in the thymus as well as the decline of the proliferative activity in the paracortex, are most likely physiological responses. The most important factor in maintaining a high production of paracortical lymphocytes under chronic stimulation is the increase in the lymphocyte mass in the paracortex.

Animals↗
PubMed1979

Dose dependency of the responses in draining lymph nodes and skin to repeated applications of oxazolone. A quantitative and histological study in mice.

The skin reactivity and lymph node responses to a large scale of different doses of oxazolone, were followed under continuous stimulation for a period of 12 days. It was found that the lack of a continuous high blast cell activity in the paracortex was a physiological response that could be observed with high dosage as well as with very low dosage. Low doses gave distinct stimulation of the paracortex without any detectable reaction in the cortex and in the medulla. Manifest stimulation of these compartments required considerably higher doses. A marked paracortical response was the only lymph node change required for development of a typical delayed type skin response. When germinal centres and plasma cells had developed, the skin reactivity was also found to change characteristically.

Animals↗
PubMed1979

A rapid method for estimating volume ratios.

A rapid stereological method is proposed for estimating the volume ratio V(K2)/V(K1) of two bodies K1, K2 such that K2 is embedded in K1. If K1, K2 fit approximately into a 'star specimen' model, then a single section, taken at a certain level through K1, provides a rather accurate estimate of V(K2,/V(K1). For a population of moderately similar star specimens, a constant sectioning level can be estimated from a sample using a least squares criterion. A pilot experiment involving mouse lymph nodes, aimed at estimating the mean and the variance of the individual fractions V (paracortex)/V(node), indicates a fair robustness against deviations from the model.

Anatomy↗
PubMed1979

Repreoducibility of a method for a graded stenosis in tubes and vessels of small calibres. An in vitro and in vivo experiment.

The reproducibility of a previously described method for graded stenosis has been tested in a model experiment and by repeated stenosis of the portal vein in rats. In the model experiment, the method was tested in terms of flow variations; in the animal experiment, in terms of prestenotic pressure variations. In the model experiment, the coefficient of variation in repeated stenosis was less than 3%. In the animal experiment, repeated stenosis constantly produced the same high level of pressure. The present method is discussed in relation to a theoretical optimal standard and found to be satisfactory.

Animals↗
PubMed1979

Prehepatic portal hypertension in the rat. Immediate and long-term effects on portal vein and aortic pressure of a graded portal vein stenosis, followed by occlusion of the portal vein and spleno-renal collaterals.

The creation of a portal vein stenosis with a diameter of 1.2 mm in Wistar rats resulted in a sustained elevation of the portal vein pressure to approximately twice the control value lasting for at least 8 weeks. The alterations in portal vein pressure following occlusion of the stenosed portal vein and splenorenal collaterals, either separately or in combination, indicate that a considerable quantity of portal blood is diverted into the inferior caval vein through the splenorenal collaterals, and that the development of these collaterals occurs during the first 3-4 weeks after the establishment of the stenosis. The concomitant reduction in aortic pressure and increase in heart rate following total occlusion of the portal vein were most pronounced during the first weeks after stenosis, and were probably due to diminished venous return to the heart.

Animals↗
PubMed1979

Porto-hepatic bypass by organohepatopexy in rats with prehepatic portal hypertension. Formation of new venous porto-hepatic collaterals following omento-, jejuno-, and splenohepatopexy, and their effect on portal vein pressure.

Transposition to the liver of the greater omentum; the jejunum, and the spleen in 3 groups of rats with prehepatic portal hypertension due to a calibrated portal vein stenosis with a diameter of 1.2 mm resulted in the formation of new venous collaterals from the transposed organs into the liver parenchyma. The collaterals were visualized macro- and microscopically, as well as angiographically, and were found to drain into intrahepatic branches of the portal vein, sinusoids, and hepatic veins. The portal vein pressure 8 weeks after stenosis and transposition was found to be significantly lower in rats with transposed organs than in controls. The collaterals were sufficiently well developed to significantly reduce the increase in portal vein pressure that follows acute occlusion of the portal vein and the natural splenorenal collaterals.

Animals↗
PubMed1975

Two-stage occulsion of the protal vein in the rat:survival related to weight variation and the interval between partial and total occulusion.

A portal vein stenosis with a diameter of 1.1 mm was performed in female Wistar rats of four different weight groups. The mortality rate was found to increase with increasing weight of the animals, a near linear correlation between mortality rate and body weight being found. Severe circulatory disturbances of the small intestine with haemorrhage and necrosis of the bowel wall were a prominent finding at death. In the survivors total occulsion was carried out at varying times, from 48 h after the first operation, and the mortality rates were recorded. A major contributing cause of death appeared to be ischaemic infarction of the liver. Only a slight congestion of the duodenum was found and no circulatory disturbance of the small intestine. Thus by 48 h the porto-systemic collaterals are sifficiently developed to prevent subsequent venous congestion. The survival rates showed a significant increase when the time interval between partial and total occlusion was extended from 48 to 72 h. This may be due to an increased blood flow through the hepatic artery and collateral arteries to the liver.

Animals↗