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Biomedical subjects

Y Collan

Publications and source records attributed to Y Collan.

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

Tumor-producing activity of dithranol (anthralin) and two of its 10-acyl analogs in the dorsal skin of female NMRI mice.

The tumor-producing activity of local applications of dithranol, 10-propionyl dithranol and butantrone was studied in 420 female white NMRI mice. An initiation with 20 micrograms of 7,12-dimethyl-benz(alpha)anthracene (DMBA) was followed 2 weeks later by three applications per week of the test compounds in 50 microliters of acetone for 50 weeks. Several control groups receiving only acetone or DMBA and test compounds without DMBA were included. Dithranol and 10-propionyl dithranol caused transient, although serious, skin irritation during the first 2 weeks of the treatment. Hyperplasia was a common finding in the same groups at the end of the treatment. Dithranol (3.5 mM) induced 11 papillomas in 8 mice (26.7%) without DMBA and 29 papillomas in 17 mice (56.7%) with DMBA. 10-Propionyl dithranol was tumorigenic as well: 3.5 mM caused 15 papillomas in 11 mice (36.6%) without DMBA and 28 papillomas in 17 mice (56.7%) with DMBA and 1.5 mM with DMBA caused 7 papillomas in 6 mice (20%). In the butantrone groups, there was only one single papilloma with the 1.5 mM concentration plus DMBA. It is concluded that, in contrast to dithranol and 10-propionyl dithranol, butantrone (3.5 mM) is not tumorigenic in the dorsal murine skin.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1984

Reduction of the lethality and the nephrocalcinotic effect of single fluoride doses by magnesium in rats.

Magnesium chloride, administered by gavage to fasting young rats, 30 min prior to sodium fluoride, elevated the LD50 for fluoride from 76 to 104 mg/kg body wt. The LD50 was elevated to greater than 180 mg/kg when magnesium was given in a dose equivalent to 2 or 3 times that of fluoride. In two experiments, a dose of 50 mg F/kg caused a mean 14- and 19-fold increase above the level of the control animals in the renal calcium content. The nephrocalcinotic effect of fluoride was nearly completely prevented by administering magnesium in a dose which is 3-fold the equivalent of the fluoride dose 30 min prior to fluoride.

Animals↗
PubMed1983

Mitochondrial flocculent densities in ischemia. Digestion experiments.

Flocculent densities appear in the mitochondrial matrix during ischemic damage. These densities were examined in kidneys after 2 hours of autolysis. The samples were embedded in water-miscible glycol methacrylate (GMA). Ultrathin sections on copper grids were digested with pronase, trypsin, ribonuclease T1, various phospholipases (A2, C, D), lipase, and desoxyribonuclease I. For statistical analysis the mean number (+/- SD) of densities per mitochondrion was determined in tubular epithelial cells. A statistically significant (p less than 0.001) decrease in the number of densities was apparent after treatment with pronase (75.5%) of the densities digested completely) and with trypsin (43.3% of the densities digested completely). Digestion with other enzymes did not significantly decrease the number of densities. This study provides quantitative support for the hypothesis that flocculent densities are composed of proteins, most probably mitochondrial membrane proteins or matrix proteins. The results do not support the hypothesis that RNA, neutral lipids, phospholipids or DNA are major constituents of these structures.

Animals↗
PubMed1983

Nasal cancer and occupational exposures. Preliminary report of a joint Nordic case-referent study.

Nasal and sinus paranasal cancers have been associated with several occupational exposures, for example, dust from hardwood, nickel and unspecific agents occurring in the boot and shoe industry. A joint Danish-Finnish-Swedish case-referent investigation was initiated in 1977 to study further the connection between nasal and sinus paranasal cancers and various occupational exposures. All new cases of these cancers were collected from the national cancer registers (Finland & Sweden) or from hospitals (Denmark). Those still alive who agreed to the interview (N = 167) were individually matched for age and sex with patients with colonic or rectal cancer. A detailed telephone interview was performed according to a standardized procedure. Both the cases and referents thought that their condition was the one under study. The exposures were coded blindly by an experienced industrial hygienist. The results showed associations between nasal or sinus paranasal cancer and exposure to hardwood or mixed wood dust (discordant pairs 14/2); softwood dust alone (13/4); chromium 16/6); nickel (12/5, not significant); welding, flamecutting, and soldering (17/16); and lacquers and paints (12/0). Hardwood dust exposure showed a connection with adenocarcinoma. Softwood dust exposure alone was associated with epidermoid and anaplastic carcinomas. No associations were found for a number of exposures, including agricultural chemicals, textile dust, asbestos, quartz dust, organic solvents, and leather work. Possible exposure to formaldehyde was evenly distributed between the cases and referents.

Adult↗
PubMed1982

Monoclonal gammopathy with neurological signs and symptoms. A clinical, neurophysiological and muscle biopsy study.

Clinical, neurophysiological and muscle biopsy findings in ten patients with monoclonal gammopathy are reported. Three patients had polyneuropathy, one had hemiparkinsonism, one migraine and radicular symptoms and one paresthesiae and radicular symptoms. Amyloidosis was not found in muscle biopsy specimens. All but one patient with neurological findings also had positive immunofluorescence staining for tissue-bound immunoglobulins in muscle biopsy specimens. The tissue-bound immunoglobulins usually belonged to the same class as the M-component. None of the biopsies of patients without neurological findings were positive.

Aged↗
PubMed1982

Histochemical and biochemical study of hereditary fibrous hyperplasia of the gingiva.

Four patients with hereditary hyperplasia of the gingiva were studied. Biopsy samples of gingival tissue contained subepithelial loose connective tissue with thick rounded fibroblasts or dense collagen-rich connective tissue with thin fibroblasts, which appeared to be inactive. These two types of fibroblasts differed in electron microscopy. Alcian blue-staining of intercellular material in various MgCl2 concentrations was similar in hyperplastic and control samples. Collagen from the hyperplastic gingiva appeared to be more mature than normal, based on the presence of stable, nonreducible cross lines. An investigation of growth hormone secretion and a treatment trial suggested that the growth retardation observed in earlier studies was due to normal variation in growth rates or (in one patient) to hypopituitarism associated with birth in breech presentation.

Adolescent↗
PubMed1982

Trauma, renal vein thrombosis and subsequent nephrotic syndrome.

A case of kidney trauma with local and systemic consequences is given. The patient got a trauma to right kidney region. After a fortnights latency nephrotic syndrome developed. Radiological examinations one month after the trauma revealed a partially recanalized thrombus in the right renal vein. It turned out in renal biopsy that the underlying cause of the nephrotic syndrome was acute proliferative glomerulonephritis with typical humps in electronmicroscopy. In contralateral (non-traumatized) kidney there was in renal biopsy the same type of acute glomerulonephritis as well. The course of the renal lesion was documented by a series of renal biopsies which showed improving proliferative glomerulonephritis. The time course of the events and the bilateral histological changes suggest renal trauma as the cause of acute proliferative glomerulonephritis which is a new aspect.

Aged↗
PubMed1981

Further observations in the eighth nerve in Menière's disease.

Forty patients with advanced Menière's disease were operated upon by vestibular or eighth nerve neurectomy. The biopsied nerve specimens were studed by light and electron microscopy. Round areas containing no or very few axons and bundles of proliferated processes of fibrous astrocytes were found in six cases. A combination of clinical and histopathologic findings suggests that some patients with symptoms identical to Menière's disease might have a primary neuronal disease leading to nonspecific reparative response by fibrous astrocytes.

Astrocytes↗
PubMed1981

Studies on the pathogenesis of ischemic cell injury. VI. Mitochondrial flocculent densities in autolysis.

Flocculent densities in the matrix of mitochondria have become quite important in cell pathology since, when prominent, they indicate irreversible cell injury. The morphology and chemical nature of these flocculent densities have been studied in Kidney after various periods of autolysis in vitro in whole tissue samples and in isolated mitochondria. After 30 to 60 min of ischemia, flocculent densities were seen only occasionally and they were most prominent in samples subjected to mechanical damage during isolation. However, in 2- and 4-h samples numerous densities were seen. The size of the densities increased with time, being about 1,400 A in diameter at 4 h. Densities were also seen in mitochondria isolated in medium containing EDTA. They were seen only in the mitochondrial matrix, and could occasionally be found in condensed mitochondria. Small densities were generally round but larger one varied in shape and often appeared as aggregates of smaller densities. Digestion of the densities from water-soluble glycol methacrylate embedded samples was successful with pronase, but neither acid nor lipid solvents were effective. calcium or inorganic phosphate content of isolated mitochondria did not show an increase parallel to the occurrence of flocculent densities. The results suggest that the densities consist predominantly of protein and are probably formed through denaturation of proteins of the mitochondrial matrix and/or the inner membrane.

Animals↗
PubMed1981

Lysozyme in neoplastic Paneth cells of a jejunal adenocarcinoma.

This is the first reported case in which neoplastic cells not of granulocytic or monocytic origin have been shown to contain lysozyme. A highly differentiated metastasizing adenocarcinoma of the jejunum is presented. Areas of the tumour contained cells resembling Paneth cells, that is, they contained cytoplasmic granules with 1) stained red with Masson's trichrome and 2) were shown to contain lysozyme by an immunoperoxidase technique. No argentaffin cells could be identified within the tumour. Staining of mucosubstance revealed large intestine-type sulfated glycoproteins in the tumour tissue. The presence of lysozyme-containing neoplastic Paneth cells suggests that the tumor: 1) originated from the mucosal crypts, and 2) had a high degree of cellular differentiation.

Adenocarcinoma↗
PubMed1981

Fabry's disease and cornea verticillata. A report of 3 cases.

Fabry's disease is a rare familial disorder of glycolipid metabolism which is caused by a deficiency of a lysosomal enzyme alpha-galactosidase. A Finnish family is described in which cornea verticillata was found in the father and 2 daughters. In all cases, there were symptoms suggesting Fabry's disease: febrile episodes the origin of which was not clear, limb pains and, in the case of the father, 20 years of proteinuria with elevated ESR, and hemiplegia and aphasia following a cerebral thrombosis at the age of 43. The diagnosis was confirmed by demonstration of an alpha-galactosidase deficit in the serum and urine of all patients. Deficiency of this enzyme leads to abnormally high urinary tri- and dihexosyl ceramide levels, and this was observed in the father and the elder daughter. At the age of 12, the daughter had loss of vision in her right eye as a result of occlusion of the central retinal artery. Electron microscopic (EM) examination of the father's dermal angioma suggested Fabry's disease. Computerized cranial tomography of the father revealed not only the cerebrovascular condition but also a disease affecting the white matter of the brain.

Adolescent↗
PubMed1980

Changes in mitochondrial lipids of rat kidney during ischemia.

Lipid changes in mitochondria isolated from rat kidney after various periods of ischemia were analysed by thin-layer chromatography and gas-liquid chromatography. Free fatty acids were increased at 30 min and more so thereafter. Total phospholipid fatty acids decreased steadily. The proportion of diphosphatidylglycerol (cardiolipin) in the total phospholipid fraction decreased at 30 min, but the proportion of phosphatidylcholine and phosphatidylethanolamine in the total phospholipid fraction did not change until the irreversible phase of ischemic injury. We have shown that decrease of cardiolipin in mitochondrial membrane occurs early during ischemia, and only during the irreversible phase of ischemia are phosphatidylethanolamine and phosphatidylcholine broken down. It is postulated that these phenomena are due to activation of phospholipase in the mitochondrial membrane.

Animals↗
PubMed1980

The cochlear nerve in Meniere's disease.

Cochlear nerves of 11 patients with advanced Meniere's disease were studied by light and electron microscopy. All the nerves appeared normal on light microscopy. In cross sections, the density of myelinated nerve fibers was approximately 20,000 fibers per square millimeter in most cases. In two cases, the density was reduced, about 14,000/sq mm. No correlation was found between the age of patients or the duration of the disease and the density of myelinated nerve fibers. On electron microscopy, there were several features that suggested primary axonal degeneration or segmental demyelination in the cochlear nerve.

Age Factors↗
PubMed1980

Vestibular nerve in Meniere's disease.

Biopsy specimens of vestibular nerves of 40 patients with severe Meniere's disease were studied by microscopy. In 17 patients, a translabyrinthine eighth nerve transection was done; in 23 patients, a middle fossa vestibular neurectomy was done. Many of the nerve fibers had thickened and deformed myelin coats; some were thinly myelinated fibers and some showed degraded myelin. No macrophages were present. Occasional vestibular ganglion cells had thin myelin coats. In six patients, there were lighter areas between the fibers. In these there were roughly parallel astrocyte processes, with numerous cytoplasmic filaments. The light areas were surrounded by a basement membrane. Four of these patients showed continuation of vertiginous symptoms after operation and were not helped by surgery. These patients may suffer from a neuropathy that is different from the more common causes of Meniere's disease.

Adult↗
PubMed1980

Vestibular findings in patients with acoustic neurinoma.

We studied the vestibular system of 30 patients with eighth nerve schwannoma. Preoperatively, cold and warm calorizations were performed. At operation, the utriculus and the ampulla of the horizontal semicircular canal as well as the eighth nerve were identified and removed for study. The sensory epithelium of utricular macula and ampullar crista appeared fairly normal in most cases. In one, there was tumor invasion to the labyrinth and in another patchy necrosis of the sensory epithelium. The number and quality of sensory cells varied from case to case. In cases with intact superior vestibular nerve, on light microscopy the histopathologic features of sensory epithelia did not differentiate between groups and symmetrical caloric reactions and with reduced or absent caloric reactions.

Adult↗