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Biomedical subjects

Y Collan

Publications and source records attributed to Y Collan.

At least 163 records · Page 9Linked to original sources

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↗

Neuroglial tissue in human eighth nerve specimens.

One hundred eighty nerve biopsy specimens from patients with eighth nerve tumors or other vertiginous diseases requiring vestibular neurectomy were studied. In many specimens light microscopy revealed pale areas among the myelinated nerve fibers in the neurolemmal portion of the eighth nerve. Electron microscopy showed that these were ectopic areas of glial tissue consisting of bundles of numerous cytoplasmic processes of fibrous astrocytes. The abundance of filaments within each process and the occurrence of microtubuli suggest that these processes are reactive astrocytes and accordingly are present as a consequence of the reparative potential of the astroglial tissue after a neuronal lesion. The possible functional significance of the findings is discussed.

Astrocytes↗

The combined toxicity of technical grade xylene and ethanol in the rat.

1. Inhalation exposure to xylene of technical grade (300 p.p.m. in air, 6 h a day, 5 days a week, up to 18 weeks) enhanced the overall mono-oxygenation reactions (7-ethoxycoumarin O-deethylase and 2,5-diphenyloxazole hydroxylase( as well as the UDP-glucuronyltransferase activity in rat liver microsomes. 2. The simultaneous ingestion of aqueous 15-20% ethanol as drinking fluid increased the cytochrome P-450 concn. and the mono-oxygenation activity even more than the xylene exposure alone. 3. Xylene-ethanol treatment resulted in additive or less than additive effects on the measured hepatic enzyme activities. 4. Renal ethoxycoumarin deethylase activity was enhanced both by ethanol ingestion and by xylene inhalation, and the response was additive after the combined exposure. 5. Liver histology revealed that even though the xylene exposure alone did not produce detectable liver damage, the xylene-ethanol treatment produced more severe liver damage than did ethanol ingestion alone.

Animals↗

Vestibular sensory epithelium in Meniere's disease.

Utricle and horizontal semicircular canal ampulla removed during labyrinthectomy from 11 patients with advanced Meniere's disease were studied under light and electron microscope. In light microscopy the epithelium of both sensory areas appeared fairly normal. Many sensory cells revealed fluid-filled crescents at the nucleus and many cells were extensively vacuolated. Ultrastructurally, a part of the observations were apparently artifacts due to specimen handling; some were normal, age-related findings. Some changes were considered secondary to dilation of the endolymphatic space. True signs of degeneration, seldom seen in these specimens were intraepithelial cysts, necrotic cells, and dark homogeneous masses in the sensory epithelium and dilated nerve fibers in the subepithelial tissue. No general degeneration of the utricular macula or ampullar crista seems to occur in Meniere's disease.

Adult↗

Immunohistochemical identification of renal lysozyme during allograft rejection in man.

An immunoperoxidase staining method was used to identify lysozyme in biopsy or transplantectomy specimens of human renal allografts during reversible and irreversible rejection of the grafts. Proximal tubules in apparently functioning nephrons showed lysozyme staining. In irreversibly rejected grafts, infiltrating mononuclear phagocytes in and near peritubular and glomerular capillaries also stained intensely for lysozyme. In acute necrotizing arteritis, lysozyme-positive cells (mononuclear phagocytes) infiltrated the blood vessel wall. The presence of infiltrating lysozyme-positive cells in the transplant was consistent with poor graft survival. The variation in lysozyme staining of proximal tubular cells apparently was a reflection of the differences in the reabsorption capacity of the tubular cells, attributable to the tubular dysfunction of renal allografts. The infiltrating lysozyme-positive cells probably contribute to the increased urinary excretion of lysozyme during acute rejection.

Adolescent↗

Electron microscopy of nephropathia epidemica cell nuclei in kidney biopsies.

Ultrastructural changes in cell nuclei were studied in kidney biopsies from 18 patients suffering from Nephropathia epidemica. Three patients showed small nuclear particles in a large aggregate in a few cells of the distal tubule. The particles had a diameter of about 30 nm and their occurrence was not associated with intravenous glucose infusions. Large light nuclear bodies were numerous in the nuclei of both interstitial and tubular cells. Many showed strands of darker material about 35 nm in diameter at their center. Nuclear vesicles with varying amounts of membrane debris were seen in both tubular and interstitial cells. Occasional interstitial lymphocytes showed abnormal margination of chromatin. Of the changes observed the small nuclear particles are not found in kidney biopsies in other conditions and it is possible that they are aggregates of viral protein.

Cell Nucleus↗

Selective vitamin B12 malabsorption with proteinuria. Renal biopsy study.

Percutaneous renal biopsy were performed on 5 patients with selective vitamin B12 malabsorption of whom 3 had proteinuria. Light microscopy showed slight prominence of the mesangial areas but otherwise the findings were normal. Electron microscopy showed increased mesangial matrix, thickening of the basement membrane at the mesangial areas and dark mesangial deposit. Light flocculent subendothelial material, moon craters, membranous convoluted structures, extracellular round particles and occasional intracellular microtubular inclusions were also seen in the glomeruli. The tubular basement membrane appeared thickened around a few tubules, showing membranous vesicular debris and convoluted structures. The capsular membrane also showed vesicular debris. On immunohistochemical examination the glomerular deposits contained immunoglobulins but not complement - an argument against their immunological nature. Deposits were seen only in patients who had been on inadequate treatment for years before the biopsy. Adequate treatment after correct diagnosis decreased the amount of deposits. Proteinuria did not apparently depend on the presence of glomerular deposits.

Adolescent↗

Menière's disease: morphological findings in eighth nerve and vestibular end organs.

37 patients with advanced Menière's disease were operated on by translabyrinthine 8th nerve neurectomy or middle fossa vestibular neurectomy. Cochlear and vestibular nerves, epithelia of the utricular macula and ampullar crista of horizontal canal were studied. All specimens were fairly well preserved and the microscopic studies suggested that there is no general deterioration of these structures even in long-standing, advanced Menière's disease, but some minor deviations from normal are present in individual cells.

Adult↗

Functional and histological findings in acoustic neuroma.

27 patients with acoustic neuroma were operated on by translabyrinthine tumor removal. At operation 8th nerve compartments were identified and removed for study. Results of the audiological test battery and vestibular tests were compared with histological state of the nerve specimens studied. The tumor appears only seldom to invade the cochlear nerve in cases with 'cochlear' hearing loss, but in the majority of cases with 'retrocochlear' hearing loss the cochlear nerve is invaded.

Cochlear Nerve↗

Histological grading of transitional cell tumours of the bladder. Value of histological grading (WHO) in prognosis.

Mortality among 139 patients with transitional cell tumour of the bladder was studied. Tumours were reevaluated according to the grading system recommended by WHO. The absolute 5-year survival of histologically benign papilloma cases was 68%, of grade I carcinoma cases 64%, of grade II carcinoma cases 42% and of grade III carcinoma patients 34%. Clinical staging (UICC), however, would have been more effective than histological grading (WHO) for prognostic purposes. 3 of the 14 patients with histologically benign papilloma in this study developed grade I carcinoma during follow-up periods of between 4.5 and 24 years. Following radical treatment all recurrences were papillomas. The study suggests that histological grading should be used to complement clinical staging in prognosis and that with half-yearly check-ups and elimination of any tumours thus detected, patients with papilloma rarely develop carcinomas of higher grade than grade I.

Aged↗

Mortality among Finnish doctors, 1953-1972.

The mortality with respect to the total population of Finnish physicians during the period 1953 to 1972 has been analysed and compared with the corresponding statistics for the general Finnish population, for Finnish foundry workers, and for American physicians. It was found that the overall mortality was lower for male physicians than that for the general population or for foundry workers, but was clearly higher than that for American physicians. Male physicians did not exhibit any major differences from the general population with regard to cardiovascular diseases and suicide, but had a lower mortality from malignant neoplasms, accidents and "other diseases" (including infectious diseases). The explanation of cancer mortality being lower than expected among male physicians was mainly to be found in a deficit in lung cancer. Although female physicians had higher life expectancy than male physicians and the female general Finnish population, they did not show any clear deficit for cancer. In respect of all specialists, surgical specialists had the lowest mortality; general practitioners had the highest mortality. Most of these variations were attributable to differences in coronary mortality, but mortality from lung cancer was also remarkably low among surgeons. Differences of a similar type were also found between occupational sub-categories; private practitioners had the highest, and research workers and central hospital physicians the lowest mortality figures. The lower cancer mortality among male physicians, as contrasted with the general population, is probably attributable to differences in smoking habits; about 22% of male physicians smoked in 1973, whereas earlier studies by others have indicated that the corresponding proportion was about 50% in the general population. In contrast, the differences in mortality between different specialist categories probably arises from other factors, since Finnish physicians reportedly display a relatively homogeneous smoking pattern.

Adult↗

Effects of intermittent styrene inhalation, ethanol intake and their combination on drug biotransformation in rat liver and kidneys.

The modifying effects of daily ethanol ingestion in the drinking water as a 15 % solution (v/v) on drug biotransformational changes induced by inhalation exposure to styrene (300 ppm or 1260 mg/m3, 6 h daily, 5 d/week, up to 17 weeks) were studied in rat liver and kidney. The drug hydroxylation activities (7-ethoxycoumarin O-deethylase and 2,5-diphenyloxazole hydroxylase) both in liver and in kidneys were increased more by ethanol ingestion than by styrene inhalation. When administered in combination, styrene and ethanol exerted mostly an additive enhancing effect. However, hepatic NADPH-cytochrome c reductase activity was reduced both in styrene and in ethanol-treated rats. Hepatic styrene oxide hydratase activity was virtually unaffected by styrene treatments. The depression of glutathione concentration in liver was greater after styrene-ethanol than after styrene treatment alone. The hepatic UDPglucuronosyltransferase activity was enhanced slightly both in styrene and in styrene-ethanol rats. The binding affinity of styrene towards cytochrome P-450 was increased after styrene inhalation as shown by lowered K8 values. The perirenal fat concentration of styrene showed a rough inverse relationship to the overall monooxygenation activities in liver and kidney. Despite the additively induced enzyme activities in styrene-ethanol-treated rats the accumulation of styrene in fat of these animals was on the whole somewhat greater, suggesting that these two solvents in vivo also have mutual inhibitory effects on biotransformation.

Animals↗

Electron Microscopy of Nephropathia Epidemica. Glomerular changes.

Electron microscopical changes in the glomeruli in 20 kidney biopsies from 18 patients, who were suffering from or had lately suffered from Nephropathia epidemica were studied. Various kinds of deposits were seen. Under the endothelial cells there were collections of light flocculent material. Small dark deposits were seen in the mesangium at the mesangial cell processes, inside the thickened basement membrane, and occasionally on the epithelial side of the membrane. Large deposits were seen around mesangial cells in the mesangium. Deposits were less numerous than in chronic immune complex diseases. The intramembranous or subepithelial deposits were associated with "moon craters", membranous convoluted structures or membrane debris. Granular extracellular mesangial material, round extracellular particles and intraendothelial microtubular inclusions were occasionally seen. In two of our cases occasional capsular epithelial cells showed numerous myelin bodies. Typical viruses were not seen in the glomeruli. The findings are in accord with the short period of scanty immune complex deposition in the glomeruli in the clinically active phase of Nephropathia epidemica.

Adolescent↗

Ultrastructural features of spiral ganglion cells. A study of patients with hearing loss of varying origins.

Fresh specimens of the acoustic nerve that were obtained during vestibular neurectomy or acoustic neuroma removal were studied for structure of the spiral ganglion cells. These were large, round or oval cells with many cytoplasmic organelles and were surrounded by Schwann cells. Schwann cells formed a single layer or perikaryal sheath and the cells were thus unmyelinated. In one case the specimen contained part of the spiral ganglion, but in six others spiral ganglion cells were found outside of Rosenthal's canal, among the myelinated nerve fibers. In three cases the ear was deaf due to cochlear insult, but the nerve fibers and ganglion cells showed no retrograde degeneration. The neurophysiologic features of the cochlear nerve should be considered because unmyelinated ganglion cells may have a different conduction capacity in comparison with thickly myelinated cells.

Adult↗

Pathologic features of the cochlear nerve in profound deafness.

Cochlear nerves transected in the internal meatus were studied in six totally deaf ears and in one ear with profound deafness. In five ears deafness had followed surgical procedures in the oval window, in one it was the result of a mumps infection, and one was probably due to a virus infection or a vascular lesion. In four cases there was no great reduction in the nerve fiber population and the ultrastructure appeared normal. In three nerves there was a reduction in the number of nerve fibers, interfibrillar fibrosis, and disorganized material or extensive degenerative changes in the myelin sheaths. In all specimens artificial myelin changes were seen that apparently resulted from manipulation of the specimens at removal. Analysis of these cochlear nerves suggests that retrograde degeneration after severe cochlear insults may not be as frequent as has been thought on the basis of animal studies.

Adult↗

Eighth nerve in acoustic neuromas. Special reference to superior vestibular nerve function and histopathology.

Eighth nerve specimens were removed during acoustic neuroma surgery, and findings were related to cochlear and especially to superior vestibular nerve function as studied by conventional caloric testing in 21 cases. The origin of the tumor was in eight cases the inferior and in two cases the superior vestibular nerve, and in eight cases the vestibular nerve without more specific localization. In three advanced cases the exact site of origin could not be determined. Leaving age-related changes out of account, the utricle and horizontal canal ampulla appeared normal in all ears except one in which the ampulla was replaced by tumor tissue. In 11 ears the superior vestibular nerve was histologically intact and three of these ears also showed normal caloric responses. In seven ears there was a canal paresis, and in three no reaction was obtained. The ten ears with partial or total nerve invasion by tumor either showed a weak reaction or no response at all. It is likely that an early conduction block arises in both cochlear and vestibular nerves, and reduced reactions to appropriate stimuli do not warrant conclusions that the numbers of anatomically intact nerve fibers possibly are reduced.

Adult↗

Cochlear nerve in neurilemomas. Audiology and histopathology.

Correlative data between the histopathologic changes in the cochlear nerve and audiologic findings are reported in 16 cases of neurilemomas. Poor speech discrimination, positive or absent recruitment, excessive adaptation, or separation of forward vs reverse continuous tone Bekesy tracings did not correlate with the number of preserved nerve fibers. There were several cases with profound hearing loss in which the nerve fiber population approached normal. Histologically, pathologic changes included dilated fibers and increased interfibrillary collagen. In many specimens the fibers were further apart than normally, especially in the immediate vicinity of the tumor, and many lay between tumor cells. The tumor-nerve interface was usually gradual and no abrupt change appeared at the transition from the nerve to the tumor, the Schwann cells appearing to continue as tumor cells. Nonspecific changes apparently due to specimen handling were seen in some areas of most specimens.

Adult↗