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Biomedical subjects

A Stark

Publications and source records attributed to A Stark.

At least 109 records · Page 6Linked to original sources
PubMed1984

Human osteogenic sarcoma: fine structure of the chondroblastic type.

The fine structure of representative regions of four chondroblastic osteogenic sarcomas was studied. These regions contained four morphologically distinguishable subtypes of chondroblastlike cells. In addition, multinucleated giant cells, fibroblastlike cells, and macrophagelike cells were present, along with small populations of unclassifiable cells forming at least two subgroups of cells likely to be of a neoplastic nature. With only one exception, all types of chondroblastlike cells were separated by wide zones of extracellular matrix. The large multinucleated cells showed a fine structure that differed from that seen in multinucleated giant cells of other tissues. The evidence suggested that the multinucleated cells in the chondroblastic osteogenic sarcomas were active in phagocytic functions. It is not clear whether or not they are neoplastic in nature. Osteoblastlike cells were not encountered in the chondroid areas of the osteogenic sarcomas studied. On the basis of the findings it is concluded that the observed fine structural polymorphism of the chondroblastlike cells may reflect differences in maturation and differentiation among these cells. The most well-differentiated cells (type 1) appear to be able to exert secretory functions.

Adolescent↗
PubMed1984

Human osteogenic sarcoma: fine structure of the fibroblastic type.

The fine structure of representative regions of nine fibroblastic osteogenic sarcomas was studied. As judged by light microscopic criteria, the tumors represented both highly malignant (grades 3-4) and less malignant (grade 2) varieties. By electron microscopy, six basic cell types were found in the selected regions (fibroblastlike, histiocytelike, and myofibroblastlike cells, along with xanthoma cells, multinucleated giant cells, and undifferentiated cells). In addition, occasional osteoblastlike cells were encountered. Fibroblastlike cells in general, and especially in grade 2 tumors, showed a fine structure, enabling differentiation from osteoblastlike cells. Multinucleated giant cells were of two morphologic types, and the fine structure appeared to be related to the malignancy potential and differentiation of the tumors. Many multinucleated giant cells in grade 2 tumors had a ruffled border and appeared to be highly active in digestive events (especially phagocytosis of whole cells and portions of cells). Accumulation of variable amounts of lipid in droplet form was common in the various types of cells present in the tissues. The observations were discussed with particular emphasis on the interrelationships and functional roles of the cells.

Adolescent↗
PubMed1983

Human osteogenic sarcoma: fine structure of the osteoblastic type.

The fine structure of representative regions of 13 osteoblastic osteogenic sarcomas was studied. These regions contained four morphologically distinguishable subtypes of osteoblastlike cells. In addition, fibroblastlike and chondroblastlike cells were present, along with multinucleated giant cells, leukocytes, macrophagelike cells, and small populations of histogenetically unclassifiable (but probably neoplastic) cells. The morphologic evidence was compatible with the view that the variations in appearance among the subgroups of osteoblastlike cells reflected differences in maturation and differentiation of these cells. In at least one subgroup, the morphologic findings suggested that the cells were capable of manufacturing a secretory product. The multinucleated giant cells occurring in genuine tumor areas appeared to be closely related to neoplastic osteoblasts. The presence of chondroblastlike cells in the tissues illustrates that cells with a diverging differentiation can occur in an osteoblast-dominated cell population. This agrees with the view that the neoplastic cells originate from a mesenchymal stem cell with potential for multifaceted differentiation.

Adolescent↗
PubMed1983

Amputations for vascular insufficiency.

A study was carried out of 302 major amputations for vascular insufficiency in the lower limb with respect to levels of amputation, postoperative revisions, re-amputations on a higher level and postoperative mortality. This information was related to vascular disease (diabetes mellitus/arteriosclerosis) and to the experience of the surgeon. There was a high incidence of above-knee amputations both of diabetics and arteriosclerotics and the rate of complications was high for "senior" as well as "junior" surgeons. The amputations were performed during 1978 and the study has shown that there is an urgent need to lower the level of amputation without increasing the rate of complications. The study indicates that there is a need for further information about the problems involved in rehabilitation of above-knee amputees.

Aged↗
PubMed1982

Human osteogenic sarcoma. Study of the ultrastructure, with special notes on the localization of alkaline and acid phosphatase.

The morphology of 26 cases of osteogenic sarcoma was studied using electron microscopic techniques, and the localization of acid and alkaline phosphatase activity at the ultrastructural level elucidated. Four different cells were present in the tumours: osteoblast-like, fibroblast-like, chondroblast-like, and multinucleated giant cells. The osteoblast-like cell was present in most of the tumours studied. Acid phosphatase activity was present in lysosome-like structures of almost all the cell-types studied. Alkaline phosphatase activity was noted in or on the plasma membranes and associated vesicles of osteoblast-like, fibroblast-like, and multinucleated giant cells. The abundant reaction product deposition of alkaline phosphatase as compared with the lower acid phosphatase activity is in agreement with the nature of this bone-forming tumour. The results of the histochemical studies have added to the understanding of the pathobiology of the different cells composing osteogenic sarcomas.

Acid Phosphatase↗
PubMed1982

Function after pelvic tumour resection involving the acetabular ring.

Seven patients subjected to pelvic tumour resection involving the acetabular ring were analyzed with respect to function. In addition to conventional clinical assessment gait was analyzed objectively by means of an electronic walk-way and residual hip-muscle power tested by means of a Cybex II dynamometer. Functional results reported by the patients with respect to pain, walking and working capacity appeared better than those elicited by clinical examination. All patients exhibited a marked pelvic tilt and a positive Trendelenburg sign. Only one patient walked without any kind of support. Leg-length discrepancy was on an average 6 cm. Objective gait analysis disclosed that all patients had reduced weight-bearing time on the operated side as compared to the non-operated. This, however, was clearly less pronounced for those patients who appeared best with respect to pain, walking and working capacity. These patients also showed the best hip extension power which appeared more important from a functional point of view than hip flexion and, surprisingly, hip abduction power. Radiographic examination showed that bony support for the proximal femur, provided either by the formation of a bone shelf from the remaining iliac bone or by the remaining iliac bone itself, was of decisive importance for function. The results of the present study show that pelvic tumour resection involving the acetabular ring, provided radical tumour removal can be achieved, constitutes a feasible alternative to hemipelvectomy from a functional point of view.

Acetabulum↗
PubMed1982

Total hip replacement with or without trochanteric osteotomy.

In a consecutive series of primary total hip replacements (THR) 54 patients were operated upon with and 78 patients without trochanteric osteotomy. Follow-up at least 2.5 years postoperatively failed to disclose any differences between the two groups in bleeding during operation, the incidence of early complications or the infection rate. A longer operation time was noted for the osteotomized group. Mechanical failure was more frequent in the non-osteotomized group. The clinical end result was similar in both groups. In complicated cases or when accessibility to the operation site is poor a trochanteric osteotomy is recommended.

Femur↗
PubMed1981

[The future of women with isolated abnormal infrared thermogram of the breast (author's transl)].

Abnormal infra-red thermograms of the breast are called "isolated" when they are not accompanied by other clinical or paraclinical abnormalities. They occur in asymptomatic women systematically examined or in women consulting for mammary symptoms other than palpable nodules. Their incidence is about 10-15%. They are usually considered as "false-positive" findings, but when these women are regularly followed up breast cancers are found to occur with a frequency ranging from 5% to 38%. "False-positive" thermograms therefore imply a high risk of breast cancer. Extremely prolonged clinical surveillance with periodical radiothermic tests and, if necessary, guided biopsies are required for early detection of small-size or even impalpable mammary carcinomas.

Breast Neoplasms↗
PubMed1980

Incidence of Duchenne muscular dystrophy in New South Wales and Australian Capital Territory.

A survey was conducted during 1977 to 1978 to determine the incidence of Duchenne muscular dystrophy in New South Wales and the Australian Capital Territory. Ninety-nine cases born between 1960 and 1971 were ascertained representing an incidence rate of 18.6 per 100 000 liveborn males. Over 60% of the ascertained males were isolated cases, and only 7% of affected males had an affected males relative in a previous generation in the female line. Categorisation of ascertained cases as either "theoretically preventable" or not shows that genetic counselling alone in the present circumstances is insufficient to reduce the incidence rate significantly.

Australia↗
PubMed1978

Bronchopulmonary dysplasia: possible relationship to pulmonary edema.

The pathogenesis of bronchopulmonary dysplasia is controversial. Oxygen toxicity, mechanical trauma to the lung secondary to respirator therapy, and congestive heart failure with a left to right shunt through a patent ductus arteriosus have all been implicated. Our data suggest that in addition to these three conditions, all of which are edemagenic, infants with bronchopulmonary dysplasia have a significantly greater mean fluid intake in the first five days of life when compared with infants with respiratory distress syndrome or patent ductus arteriosus alone. We suggest that the addition of a fluid load may potentiate the effects of other factors and increase the risk of bronchopulmonary dysplasia in infants with respiratory distress syndrome who require respiratory support.

Bronchial Diseases↗