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Biomedical subjects

L Boquist

Publications and source records attributed to L Boquist.

At least 37 records · Page 2Linked to original sources
PubMed1979

Stereological study of B-cell mitochondria in alloxan-treated mice.

Using stereological techniques, including semi-automatic image analysis, the B-cell mitochondria were studied in the pancreatic islets from one group of control mice and two groups of mice killed 10 min and 60 min, respectively, after alloxan administration. Ten min following alloxan the mitochondrial volume and envelope surface densities, the mean mitochondrial volume and surface area, and the area of mitochondrial profiles were significantly increased, whereas the mitochondrial numerical density was not significantly altered. At the 60 min observation time the mitochondrial volume density, the mean mitochondrial volume and surface areas, and the area of mitochondrial profiles were significantly decreased, whereas the mitochondrial envelope surface was not significantly altered. The findings indicate a rapid swelling, followed by disintegration of the mitochondria in the B-cells of alloxan-treated mice, thereby supporting our view that mitochondrial lesions play a primary role in the development of alloxan diabetes. These lesions are believed to be due to ionic alterations in the B-cells ("Pi-pH hypothesis").

Alloxan↗
PubMed1979

Stereological study of endoplasmic reticulum, Golgi complex and secretory granules in the B-cells of normal and alloxan-treated mice.

Different B-cell organelles (lamellar and vesicular endoplasmic reticulum, Golgi complex, whole secretory granules and secretory granule cores) were studied stereologically in pancreatic islets from control mice and mice killed 10 or 60 min following alloxan injection. Ten min following alloxan a significant decrease was observed in the volume, surface and numerical densities of whole secretory granules and their cores, and a significant increase was found in the volume and surface densities of vesicular endoplasmic reticulum. At the 60 min observation time, a significant decrease was seen in the volume density of lamellar endoplasmic reticulum and Golgi complex, and in the volume, surface and numerical densities of whole secretory granules and their cores, and a significant increase was observed in the volume and surface densities of vesicular endoplasmic reticulum, and in the mean values for volume and surface of whole secretory granules and their cores. The stereological data indicate swelling of endoplasmic reticulum, decreased Golgi area, and decreased number and total volume and surface of secretory granules during the first hour after alloxan administration to mice. The observations may be consistent with inhibited insulin synthesis.

Alloxan↗
PubMed1979

Carbonic anhydrase activity in mouse endocrine pancreas.

Histochemical staining for carbonic anhydrase (CAH) was demonstrated in the mouse pancreas. Light microscopically, a strong reaction for CAH was found in the B-cell region of the islets, in blood vessels inside and outside the islets, and in centroacinar cells and ductules. In contrast, no distinct reaction was seen in the peripheral A- and D-cell regions of the islets, or in the cytoplasm of the acinar cells. A weak, irregular staining could, however, be observed in some nuclei of the acinar parenchyma. A newly-developed ultrastructural modification disclosed a distinct reaction in a varying number of the secretory granules of the B-cells, whereas a sparse, irregularly-distributed reaction was observed in the nuclei and cytoplasmic ground substance, and in association to the plasma membranes and microvilli of these cells. The CAH reaction was in all portions of the pancreas abolished by acetazolamide. The specificity of these results is discussed. The findings are suggested to indicate presence of a true CAH activity in the B-cells of the mouse pancreas.

Animals↗
PubMed1979

Extra-osseous osteosarcoma: a clinical and histopathological study of four cases.

Four cases of extra-osseous osteosarcoma were found among 242 cases recorded as osteosarcoma in the Swedish Cancer Registry during the years 1958 to 1968. The tumours occurred in middle-aged and elderly patients. Three of the tumours were situated in the proximal part of the thigh and one in the scapular region. Histopathologically, all tumours were subclassified as osteoblastic osteosarcomas. The patients were treated by primary local excision which in one case was followed by a radical en bloc excision of the entire tumour bed. All cases subjected to simple excision died of metastatic disease five to twenty-four months after diagnosis. The patient treated by en bloc excision is alive and apparently free from disease fourteen years after diagnosis.

Adult↗
PubMed1979

Laryngeal chondrosarcoma in Sweden.

Between 1958 and 1972, 5 cases of posterior cricoid chondrosarcoma were reported to the Swedish Cancer Registry. These cases, and one recently observed case of laryngeal chondrosarcoma, are presented in this study of one female and five male patients. The tumours grow slowly and recur locally, but have not metastasized, and none of the patients has died from tumour disease. The clinical and morphological findings indicate that these tumours represent secondary chondrosarcomas developing from pre-existing benign ecchondromas. The reason for the uniformity as to localization is not known. The microscopic appearance varied in different parts of the same tumour. The presently obtained data and review of the literature indicate that laryngeal chondrosarcomas are extremely rare, locally invasive, but usually not metastasizing tumours. Conservative laryngeal operation is suggested as primary treatment. Total laryngectomy is necessary only after local recurrences involving a major portion of the cricoid cartilage.

Aged↗
PubMed1979

Transplantable osteosarcoma in mice. Structural characterization of a transplantable osteosarcoma obtained in an allogenic system.

Light microscopic, histochemical and ultrastructural studies of a transplantable mouse osteosarcoma were carried out. The osteosarcoma grew in CBA mice after injection of cultured cells derived from a Dunn osteosarcoma. The tumour differed from the original Dunn osteosarcoma with respect to metastatic potential and structural features. The transplantable tumour was an anaplastic, richly vascularized fibroblastic osteosarcoma with alkaline phosphatase activity and rather sparse osteoid formation, resulting in death of the animals within 6 to 8 weeks. Virus particles were found intracellularly, mainly localized to cisterns of rough endoplasmic reticulum, and extracellularly often close to plasma membranes and collagen fibres. Sign suggestive of formation of collagen fibres by tumour cells were observed. A possible viral influence upon the tumour was suggested also by its growth behaviour in vitro. The results indicate that this new transplantable tumour, obtained in an allogenic system, represents a clonal derivative of the original Dunn osteosarcoma.

Animals↗
PubMed1979

Mitochondrion-secretory granules complexes in pancreatic islet B-cells.

Mitochondrion-Secretory Granule Complexes (MSGC) are present in rodent pancreatic islet B-cells, characteristically showing fusion of mitochondria and secretory granules, absence of granule membrane and external mitochondrial membrane at place of contact, often invagination of internal mitochondrial membrane at place of contact forming an electron lucent space directly continuous with the "halo" of the secretory granules, and occurrence of potassium pyroantimonate precipitates in either or both of mitochondria and secretory granules. The MSGC are believed to possess functional significance, possibly playing a role in translocation of ions between mitochondria and secretory granules in the B-cells.

Animals↗
PubMed1979

Influence of 1,25-dihydroxycholecalciferol on parathyroid activity in patients with primary hyperparathyroidism.

Parathyroid morphology and blood chemistry were studied in five patients with primary hyperparathyroidism treated with 1,25-dihydroxycholecalciferol (1,25-DHCC) for 2 to 11 days before planned operation. Before the institution of treatment all patients were hypercalcemic, whereas the serum immunoreactive parathyroid hormone (iPTH) concentration either was elevated or normal. During the treatment the urinary phosphate excretion was significantly increased, whereas the calcium excretion and the serum concentrations of calcium and phosphate were unaffected or only slightly changed. Serum iPTH decreased during the first days of treatment, but returned then to increased levels close to the pretreatment ones. The treatment was tolerated well by the patients. Light and electron microscopy of the removed parathyroid glands disclosed one adenoma in each of the five patients, the other glands exhibiting either a slight hyperplasia or a normal appearance. Both the adenomatous and the non-adenomatous parathyroid tissue showed a predominance of dark chief cells and three of the adenomas exhibited a varying number of atrophic and oxyphil cells. The non-adenomatous glands were composed of atrophic and dark chief cells. Signs of low functional activity were ultrastructurally observed in the parathyroid parenchymal cells. It is suggested that 1,25-DHCC treatment of patients with primary hyperparathyroidism inhibits parathyroid hormone secretion.

Adult↗
PubMed1979

Structural changes in parathyroid glands exposed to vitamin D metabolites in vitro.

Isolated parathyroid glands from normal adult Mongolian gerbils were incubated for 10 minutes to 16 1/2 hours at high, medium or low concentrations of Ca2+, with or without added 1,25-dihydroxycholecalciferol (1.25-DHCC) or 25-hydroxycholecalciferol (25-HCC), after which they were studied electron microscopically. 1,25-DHCC appeared to potentiate the inhibitory action of high calcium on parathyroid activity, whereas 25-HCC had no structurally detectable effect.

Animals↗
PubMed1978

Effect of metabolic alkalosis on the B-cell sensitivity to alloxan in vivo.

Metabolic alkalosis was induced in starved mice by treatment with NaHCO3, which did not significantly alter the blood glucose concentration, but protected against the diabetogenic effect of subsequently given alloxan. This protection and the alkalosis had disappeared 4 hr after NaHCO3 treatment. Protection against alloxan, and metabolic alkalosis, were found also in starved mice pretreated with sodium lactate. The findings indicate that metabolic alkalosis, directly or indirectly, protects against alloxan toxicity in vivo.

Alkalosis↗
PubMed1978

Osteosarcoma. A multifactorial clinical and histopathological study with special regard to therapy and survival.

A multifactorial analysis was performed on all 153 unequivocal cases of genuine osteosarcoma recorded in the Swedish Cancer Registry for the years 1958 through 1968. Cases of so-called parosteal osteosarcoma, soft-tissue osteosarcoma and osteosarcoma secondary to Paget's disease of bone were not included. The osteosarcomas were subclassified as follows: osteoblastic (69 per cent), chondroblastic (19 per cent) and fibroblastic (12 per cent). The overall 5-year survival rate was 22 per cent; 55 per cent for those who had undergone amputation above the joint proximal to the involved skeletal part, 22 per cent for those amputated on the involved skeletal part, 11 per cent for those treated with local extirpation of the tumor, and 1 per cent in cases in which the lesion was not radically removed. Tumors of the femur, humerus and scapula were as malignant as axial tumors. The former carried a 5-year survival rate of 13 per cent, regardless of whether the patients had been treated with exarticulation or amputation on the involved skeletal part. Patients with axial tumors showed a 5-year survival rate of 15 per cent. These survival data suggest that proximal amputation alone might suffice for lesions situated distally to the knee and elbow joints, while tumors in the humerus and femur should be treated with amputation combined with multicytostatic treatment or immunotherapy and axial tumors with local resection and multicytostatic or immunologic treatment.

Adolescent↗
PubMed1978

Telangiectatic osteosarcoma.

Of the 242 cases of osteosarcoma recorded in the Swedish Cancer Registry for the years 1958 through 1968 only one was found to represent telangiectatic osteosarcoma. Another case was recently diagnosed in our department. The characteristic morphologic features of these neoplasms were anaplastic stroma, high mitotic activity, osteoid-formation, widely anastomosing blood spaces, and alkaline phosphatase activity. The experience gathered indicates that telangiectatic osteosarcoma constitutes a histopathologic variant of genuine osteosarcoma with a serious prognosis, necessitating the same kind of treatment as for the genuine tumour.

Adolescent↗
PubMed1978

Giant serpentine intracranial aneurysm after carotid ligation. Case report.

A case is reported of a giant aneursym of the intracavernous portion of the left internal carotid artery that was treated initially with a left common carotid artery ligation. Six months later the aneurysm was partially removed. During this time the development and evolution of thrombus formation, a serpentine channel, and a hypervascular capsule was easily followed with recreated computerized tomography and angiography of the aneurysm.

Adult↗
PubMed1978

Factors affecting the beta-cell sensitivity to alloxan in vivo. Influence of pre- and post-treatment with protective substances.

Blood glucose and pancreatic islet morphology were studied in mice subjected to different kinds of treatment both before and after alloxan administration. d-Glucose, d-mannose, d-fructose, NaHCO3 and sodium lactate protected against alloxan when given before, but not when given after alloxan, whereas l-leucine protected when administered before, and also when injected 1 or 3 min after alloxan. No protection was seen in animals receiving l-leucine 10 min following alloxan. The findings may indicate that the mechanism for alloxan protection by l-leucine differs from that of the other compounds tested.

Alloxan↗
PubMed1978

Pancreatic B-cell sensitivity to alloxan in vivo. A study of antagonizing compounds, serum inorganic phosphate and acid-base balance.

Serum glucose, inorganic phosphate, acid-base balance and islet morphology were studied in mice subjected to different kinds of treatment before alloxan administration. In preceding studies, pretreatment with D-glucose, D-mannose, D-fructose, sodium lactate and NaHCO3, but not with D-galactose, was found to protect against alloxan toxicity. In this study alloxan antagonism was found by pre-treatment with L-leucine, but not with L-arginine or NaH2PO4. Blood analyses, carried out 10 minutes after injection of the test compounds, disclosed that the serum inorganic phosphate concentration was decreased in mice given D-glucose, D-mannose, D-fructose, sodium lactate, NaHCO3, L-leucine, and L-arginine, but was not affected in those treated with D-galactose, and was increased in those receiving NaH2PO4. With the exception of L-arginine, blood pH was increased in the groups which exhibited decreased serum inorganic phosphate concentration; pH was not affected in mice treated with D-galactose, L-arginine and NaH2PO4. Alterations in inorganic phosphate and hydrogen ion concentration may affect the B-cell sensitivity to alloxan ("Pi-pH hypothesis").

Acid-Base Imbalance↗
PubMed1977

Pancreatic islets subjected to different concentrations of glucose in vitro. A study with special regard to mitochondrial changes.

Isolated pancreatic islets of mice and gerbils were cultured for 6 days at low (2mM) or high (20mM) concentrations of glucose after which they were studied using qualitative and quantitative electron microscopy, histo- and microchemistry, and X-ray microanalysis. Compared with the islets cultured at high glucose, those subjected to low glucose exhibited enhanced succinate dehydrogenase activity, a decreased content of adenosine triphosphate, and an increased volume of B-cell mitochondria which often were rounded or oval.

Adenosine Triphosphate↗