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Biomedical subjects

M Block

Publications and source records attributed to M Block.

At least 145 records · Page 8Linked to original sources
PubMed1984

Metastatic neuroblastoma arising in an ovarian teratoma with long-term survival. Case report and review of the literature.

A case of neuroblastoma arising in an immature teratoma of the ovary in a 22-year-old woman is reported. Differentiation was grade 3 in the primary and metastases. Metastases to retroperitoneal, mediastinal, and supraclavicular lymph nodes and to bone were diagnosed 2 years after presentation of the primary tumor. Electron microscopic study demonstrated dense-core granules of the neurosecretory elements. Treatment with combination chemotherapy followed by radiotherapy resulted in complete remission which continues to the time of this report, more than 4 years after diagnosis of the primary tumor. Prolonged survival of metastasizing grade 3 immature teratoma is distinctly uncommon. The literature pertaining to this unusual tumor and to neuroblastoma of adults is reviewed.

Adult↗
PubMed1984

Quantitative analysis of a vascular tree model with the dynamic spatial reconstructor.

The accuracy in determining the three-dimensional anatomy of a vessel network by computed tomography (CT) is evaluated using a glass model of a pulmonary artery. The dynamic spatial reconstructor (DSR), a high temporal resolution, volumetric, roentgenographic, CT scanner, was used to scan the model. The glass of the model had a roentgen attenuation coefficient mu = 0.55 cm-1, which is approximately equivalent to the 20% dilution of contrast medium to be expected in the pulmonary arterial tree following a contrast agent bolus injection of 2 ml/kg in the right atrium. The model was scanned inside a 20 cm diameter Plexiglas cylinder with a 1 cm thick wall (mu congruent to 0.2 cm-1) to simulate the chest wall of a 20 kg dog, and it was filled with potato flakes to simulate lung parenchyma (mu congruent to 0.06 cm-1). In one 0.011 s scan, information for reconstruction of a stack of images of transaxial sections was recorded. Sequential scans were performed to obtain data for either maximum transaxial resolution (14 angles of view every 0.0167 s, 120 parallel slices each 1.8 mm thick) or maximum axial resolution (eight angles of view every 0.0167 s, 240 parallel slices each 0.9 mm thick) reconstructions. Estimated detectable "vessel" size, cross-sectional area, branching angle, and interbranch segment length were determined as a function of imaged slice thickness, orientation of section image, and number of angles of view (i.e., scan duration) used to make images. Retrospective selection of 0.05 s duration scan apertures at sequential 0.5 s intervals was used to simulate a typical, retrospectively gated reconstruction from a DSR scan. Using these reconstructed images, 2 mm diameter "vessels" could be readily detected and their structure quantitated. Comparing direct measurements and DSR estimates, cross-sectional area (SEE = 3 mm2), branching angles (SEE = 2 degrees), and segment length (SEE = 1 mm) all had a correlation coefficient greater than 0.99, and the regression lines showed no significant differences from the lines of identity (p greater than 0.05).

Animals↗
PubMed1984

Coronary angiographic examination with the dynamic spatial reconstructor.

The dynamic spatial reconstructor (DSR), a high temporal resolution, three-dimensional roentgenographic, computed tomography scanner, was used to scan the coronary arteries of five dogs. After one injection of contrast medium into the left main coronary artery or into the aortic root of each dog, all major epicardial coronary arteries and the septal artery could be imaged. After selective removal of all nonangiographically enhanced anatomical structures within the three-dimensional images, pseudo three-dimensional displays were generated to show the arteries from all possible views--even the strictly cranial view--so that superposition of arteries could be avoided. The geometric accuracy of the images was evaluated by comparing coronary arterial segment length measured by the DSR with postmortem measurements (r = .99, SEE = 3.12 mm, n = 35) and by measuring the stenosis produced by nine hollow plastic cylinders lodged in coronary arterial lumina via percutaneous catheterization. Three of the plugs had irregular noncircular lumina drilled into them so that the percentage of stenosis seen in some projection images underestimated the severity of stenosis. The DSR overestimated the length of a 3 mm long stenosis by 0.4 +/- 0.5 mm. The percent area reduction caused by the hollow cylinders varied between 53% and 92% and was underestimated by the DSR on the average by 7%. The correlation between DSR measurements and the direct measurements was r = .85 (SEE = 5%, n = 9). The volume of plastic in each plug (average 13.2 mm3), calculated from the length, cross-sectional area, and degree of the stenosis, showed a better correlation (r = .90, SEE = 2 mm3) with the actual plastic volume.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Glucagonomas. Ultrastructure and immunocytochemistry.

Pancreatic tumors harboring glucagon immunoreactive cells were found in four patients with diabetes mellitus. Alpha-cell (glucagon) granules were present in three tumors; pancreatic polypeptide (PP) immunoreactive cells were detected in two. In two patients the tumors were malignant and one of these had the glucagonoma syndrome; the other was a member of a family with MEN-type I syndrome. These cases illustrate three clinical subtypes of glucagonoma.

Adenoma, Islet Cell↗
PubMed1983

Unicystic ameloblastoma.

The unicystic ameloblastoma should be considered a distinct entity and treated conservatively. The following case report emphasizes the use of computerized axial tomography in the diagnosis of this lesion. The detailed histology and conservative surgical therapy is discussed.

Aged↗
PubMed1983

Measurement of systolic and diastolic flow rates in the coronary artery system by x-ray densitometry.

The reliability of a modified videodensitometric and photodensitometric sampling technique for measuring phasic flow rates in the coronary artery system was examined. Electromagnetic flow measurements were performed in a circulatory model with continuous and pulsatile flow and intraoperatively in aortocoronary bypass grafts; cineangiograms were made simultaneously. Based on the front velocities of injected boluses of contrast medium, the densitometric measurement overestimated the electromagnetically measured flow systematically by about 20%. Systolic and diastolic flow rates in aortocoronary bypass grafts and coronary arteries determined from biplane cineangiograms in 34 patients generally revealed the typical pulsatile flow pattern familiar from electromagnetic and ultrasonic flow measurements. Flow velocities in unstenosed coronary arteries were nearly identical before and after branchings of the vessels, whereas the corresponding flow rates were higher in proximal than in distal segments. The identical flow velocities in different branches of the same vessel and the low variability of this parameter in different patients may be a suitable index of the effect of stenoses on coronary arterial blood flow.

Absorptiometry, Photon↗
PubMed1982

[Determination of phasic flow speeds in the coronary vessels by means of a simple photodensitometric technique (author's transl)].

Systolic and diastolic flow rates in coronary arteries were determined from cineangiograms using a photodensitometric measurements system. The front velocity of a bolus of contrast medium was evaluated by two different methods. Measurements in aortocoronary bypass grafts showed that the photodensitometric determination of flow rates overestimated the electromagnetically measured flow by about 20%. Measurements in coronary arteries proved a good reproducibility (r=0.98) and the typical pattern of phasic flow. The velocity of flow in coronary arteries was nearly identical before and after branchings of the vessels (r=0.96).

Blood Flow Velocity↗
PubMed1982

Hyperparathyroidism and thyroid disease. A study of their association.

The incidence of hyperparathyroidism was prospectively evaluated in a group of patients with thyroid disease, and the incidence of thyroid disease was retrospectively evaluated in a group of patients specifically referred for evaluation of hyperparathyroidism. Hyperparathyroidism was ten times more frequent in thyroid patients than expected in a general medical population and was especially prevalent in patients with nodular goiter. The incidence of thyroid disease in patients with hyperparathyroidism was 38.8%. Although radiation therapy was shown to be a factor in these associations, it alone could not explain the observed frequency.

Goiter, Nodular↗
PubMed1981

Radiation carcinogenesis in man: new primary neoplasms in fields of prior therapeutic radiation.

Nine patients are presented in whom new malignant neoplasms developed in fields of prior irradiation. The prior irradiation had been administered to these patients for previously confirmed cancers, lesions suspected of being cancer (but never confirmed as such), and for non-neoplastic disorders. Each of these cases is relatively unique and several present the first association between prior radiation therapy and the subsequent neoplasm or neoplasms which developed.

Adolescent↗
PubMed1981

Treatment of stage D prostatic carcinoma with megestrol acetate.

Nine previously untreated patients with stage D prostatic carcinoma received megestrol acetate 40 mg orally three times daily. Responses included five partial regressions, two stabilizations, and two progressions. Duration of response ranged from 3+ to 33+ months, with a mean of 11.7 months and a median of 12 months. Three of five patients who had failed prior hormonal therapy remained objectively stable while receiving megestrol acetate. No gastrointestinal toxicity, gynecomastia, fluid retention, or thromboembolic complications were observed during treatment. Weight gain of 5 to 51 pounds occurred in seven of 14 patients.

Aged↗
PubMed1981

Satisfaction and distress in a community: a test of the effects of life events.

A household survey of 537 residents was conducted to test conflicting hypotheses about the correlates of life events derived from three general models of well-being: an equilibrium, a life crisis, and a positive mental health model. Consistent with the predictions of a positive mental health approach, positive life events were correlated with both reports of distress and satisfaction. Further, positive and negative events were intercorrelated; the distress effects of positive events could be accounted for to a large extent by the negative events associated with them. The findings suggest that community studies need to assess the potentially positive as well as stressful effects of life events.

Adolescent↗
PubMed1981

The pathogenesis of infantile malignant osteopetrosis: bone mineral metabolism and complications in five infants.

Bone mineral metabolism was studied in five infants aged 8 to 22 months with severe osteopetrosis. There were findings consistent with biochemical osteomalacia. These included hypocalcemia, hypophosphatemia, high serum acid phosphatase and alkaline phosphatase activity, high levels of serum parathyroid hormone, and high urinary cyclic AMP. Serum 1,25(OH)2 vitamin D3 level was high in the one patient tested. Radiographs in all infants revealed rachitic changes in the metaphyses. However, dense bones on radiographs, calcium balance studies, and radio-calcium absorption studies demonstrated markedly positive calcium balance. Iliac crest bone biopsies showed increased quantity of woven bone with abundant numbers of osteoclasts, excessive amounts of osteoid, myelofibrosis, and a decreased number of Howship's lacunae. The wide bands of unmineralized osteoid did not take up tetracycline. In vitro bone resorbing activity due to osteoclast activating factor from cultured stimulated leukocytes was normal. Bone turnover however, was now as evidenced by low urinary hydroxyproline levels. We interpret these findings as indicating there is decreased bone remodeling and resorption in spite of increased humoral stimuli and osteoclasts. Since calcitonin levels were normal for age, the most likely cause of the impaired bone remodeling sequence was defective osteoclast function. We postulate that there may be a common genetic defect in phagocyte cells, including monocytes, neutrophils and osteoclasts, which accounts for the abnormalities of mineral metabolism and previously reported hematologic, neurologic, and infectious complications.

Biopsy, Needle↗
PubMed1980

Clinical evaluation of three free-thyroxine assays.

The free thyroxine (FT4) test of Clinical Assays, Corning Medical, and Damon Diagnostics were evaluated in 245 patients. Although all three assays generally correlated well with the clinical functional status, there were apparent discrepancies in the clinically euthyroid population. All patients with discordant values had either relatively high or low triiodothyronine (T3) uptakes. In these instances, the free-thyroxine index gave a more accurate assessment of the clinical thyroid status than did the FT4. In our opinion, these findings place a critical limitation on these assays as a replacement for the free-thyroxine index.

Evaluation Studies as Topic↗