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Biomedical subjects

W Wirth

Publications and source records attributed to W Wirth.

At least 19 recordsLinked to original sources
PubMed2005

Double echo steady state magnetic resonance imaging of knee articular cartilage at 3 Tesla: a pilot study for the Osteoarthritis Initiative.

BACKGROUND: Quantitative magnetic resonance imaging (qMRI) may provide valuable measures of cartilage morphology in osteoarthritis (OA) but has been confined to sequences with relatively long acquisition times at 1.5 Tesla (T). OBJECTIVE: To test the accuracy and precision of knee cartilage qMRI with a fast double echo, steady state (DESS) sequence with water excitation (we) at 3 T. METHODS: As a pilot study for the Osteoarthritis Initiative, test-retest MR images were acquired in the knees of 19 participants with no OA to moderate degrees of clinical OA. Two double oblique coronal fast low angle shot (FLASHwe) sequences (1.5 mm slice thickness) were acquired at 3 T, and two sagittal DESSwe sequences (0.7 mm slice thickness). Double oblique coronal multiplanar reformats (MPR) were performed (1.5 mm slice thickness) from the sagittal DESSwe. Knee joint cartilage plates were quantified unpaired in random order with blinding to subject identification. RESULTS: In the femorotibial joint, precision errors (root mean square coefficient of variation in % for unpaired analysis) for cartilage volume and thickness were 3.0-6.4% with coronal FLASHwe, 2.4-6.2% with coronal MPR DESSwe, and 2.3-8.2% with sagittal DESSwe. Correlation coefficients between DESSwe and FLASHwe ranged from r = 0.88 to 1.0. In the femoropatellar joint, precision errors (sagittal DESSwe) were 3.4-8.5%. CONCLUSIONS: DESSwe permits accurate and precise analysis of cartilage morphology in the femorotibial joint at 3 T. Further studies are needed to examine the accuracy of DESSwe in the femoropatellar joint and its ability to characterise sensitivity to longitudinal changes in cartilage morphology.

Adult↗
PubMed2005

Use of novel interactive input devices for segmentation of articular cartilage from magnetic resonance images.

OBJECTIVE: To study the effect of new interactive computer input devices on cartilage segmentation in terms of time, consistency between input devices, and precision in quantitative magnetic resonance imaging (qMRI). DESIGN: We compared two new input devices, an interactive digitizing tablet and an interactive touch-sensitive screen, to a traditional mouse. Medial tibial and patellar cartilage of six healthy and six osteoarthritic knees were segmented using each input device. Cartilage volume, surface area and mean thickness were assessed using a validated algorithm and used to determine consistency and precision. Segmentation time was also measured. RESULTS: Segmenting with an interactive touch-sensitive screen reduced segmentation time by 15% when compared to the traditional mouse but we found no significant difference in segmentation time between the interactive digitizing tablet and the traditional mouse. We found no difference in consistency or precision of cartilage volume, mean thickness or surface area between the three input devices tested. CONCLUSIONS: We conclude that measurements of cartilage made using articular cartilage segmentation from MR images are independent of the input device chosen for user interaction.

Adult↗
PubMed1999

[Primary osteosarcoma of the thyroid gland].

Primary extraosseous osteosarcoma of the thyroid gland is a very rare tumor with a poor prognosis. Only few cases have been reported in the literature. Metastases of osteosarcoma in the thyroid gland were also found but are very seldom. A primary thyroid tumor with osteosarcomatous differentiation in a 82-year-old man is presented and the histopathological classification, biological features and possible mechanisms of the occurrence of such thyroid tumors are briefly discussed.

Aged↗
PubMed1997

[Sonographic appearance of the canine kidney compared with pathologic-histologic morphology].

Aim of the present study was to evaluate the possibility whether the ultrasonographic appearance of the canine kidney can be attached to a specific histopathologic diagnosis. The sonographic examination was performed in 117 dogs that were presented in the Small Animal Clinic of Hannover Veterinary School, Germany, for euthanasia. After the euthanasia the kidneys were exenterated and evaluated pathohistologically in the Department of Pathology of Hannover Veterinary School. According to the sonographic changes the patients were classified into seven different groups and compared with the histopathologic findings. The results of this study demonstrate that it is currently not feasible to relate a gray-scale sonography image of a diffuse renal parenchymal alteration to a specific histopathologic diagnosis. It remains to be seen if it is possible to improve the renal ultrasonography with new diagnostic methods, e.g. color-doppler ultrasonography.

Aging↗
PubMed1997

Dynamics of haemostasis during the oestrous cycle and pregnancy in bitches.

The blood coagulation status was studied in 31 bitches of different breeds during 33 oestrous cycles and during nine pregnancies. Two other bitches were ovariohysterectomized and received subcutaneous injections of oestradiol benzoate for 7 consecutive days. Blood samples were taken in early and late follicular phases, at ovulation, at day 1 after the end of oestrus as determined by cytology, at days 30, 60, 90 and 120 of metoestrus and in anoestrus. The samples were analysed for the concentrations of fibrinogen, fibrin(ogen) degradation products, as well as for the prothrombin time, the activated partial thromboplastin time, the antithrombin III activity, the number of platelets and the haematocrit. In other blood plasma samples the concentrations of oestradiol and progesterone were measured. In the two bitches that were ovariohysterectomized and received subcutaneous injections of oestradiol benzoate for 7 consecutive days, the coagulation parameters and hormones were examined in blood samples collected at appropriate terms and time intervals as in intact dogs. The significantly increased concentrations of fibrinogen and fibrin(ogen) degradation products, the large number of platelets and the decreased antithrombin III activity observed during the luteal phase of the nonpregnant and pregnant bitches are attributed to direct or indirect effects of the high peripheral progesterone concentrations. In the mid-luteal phase (day 30) this activation was more distinct during pregnancy than in the nonpregnant dogs presumably owing to additional effects of local processes in the uteroplacental area. Influences of high concentrations of oestradiol were not observed either during the follicular phase of the intact bitches or after oestradiol benzoate administration in the ovariohysterectomized dogs.

Analysis of Variance↗
PubMed1997

[Antithrombin III activity in health cats and its changes in selected disease].

Measurements of the antithrombin III (AT III) activity in feline plasma with a thrombin dependent chromogenic substrate assay using an automatic analyzer showed a high within run precision. The coefficient of variance was 1.82% (normal AT III activity) or 3.19% (decreased AT III activity), respectively. In comparison with the feline pool plasma the AT III activity in canine plasma was similar (93.7%) and in human reference plasma was lower (71.7%). Respecting healthy cats aged more than three months no distinct influence could be demonstrated on the AT III activity neither of age nor of gender (p = 0.2180). Based on the 2.5%- and 97.5%- quantile the reference range was 83.5-122.5% respecting the total number of healthy cats (n = 138) or 82.6-121.5% concerning the 116 European Shorthair cats. AT III activity of cats infected with feline immunodeficiency virus (n = 37) or teline leukemia virus (n = 20) as well as of cats suffering from different solitary tumors (n = 8) was not distinctly different from the control group (p > 0.05). On the contrary, a significant decrease of AT III activity was found in traumatized cats (n = 20; median = 80.8%, p < 0.0001) as well as in animals with chronic renal failure (n = 20; median = 91.7%, p = 0.0228) which can be mainly attributed to a consumption reaction or excessive renal loss, respectively.

Animals↗
PubMed1996

[Candidiasis of the liver following successful chemotherapy of acute myeloid leukemia (Fab type 6) and recovery with oral fluconazole therapy].

The spectrum of disseminated candidiasis includes both an acute and chronic presentation. In contrast to the acute form, chronic disseminated candidiasis (hepatosplenic candidiasis) often occurs late after granulocytopenic episodes in patients undergoing chemotherapy, usually for acute leukemia. We discuss a female patient who underwent extensive successful chemotherapy for acute myelogenous leukemia (FAB type 6) and who developed chronic hepatosplenic candidiasis 19 months later. Therapy with amphotericin B and flucytosine was not successful and a cure was effected only after long-term oral fluconazole treatment. Diagnostic problems, possible reasons for the observed failure of amphotericin B treatment, and the current use of fluconazole in disseminated candidiasis are discussed.

Aged↗
PubMed1995

Urethral pressure response to smooth and skeletal muscle relaxants in anesthetized, adult male cats with naturally acquired urethral obstruction.

The effects of the skeletal muscle-relaxing drug dantrolene sodium alone, and in combination with the alpha 1-adrenergic antagonist prazosin, on the urethral pressure profile were investigated in male cats with obstructive lower urinary tract disease. Decreases in mean segmental intraurethral pressure induced by dantrolene (n = 3) or dantrolene in combination with prazosin (n = 3) were evaluated statistically, using a paired design. Statistical analysis was applied to absolute (mm of Hg) pressure values. Intravenous administration of dantrolene alone (1 mg/kg of body weight, n = 3) significantly decreased pressure in the postprostatic/penile urethral segment, but did not decrease prostatic urethral pressures. Dantrolene in combination with prazosin (0.03 mg/kg IV) caused a 20% pressure decrease in the prostatic segment (P = 0.060). Preprostatic urethral pressure was not significantly affected by either treatment regimen in the small pool of cats studied. There was no difference in baseline pressures (mm of Hg) in the 3 intraurethral segments of these 6 recently obstructed male cats, compared with historic baseline pressures (mm of Hg) in the 3 intraurethral segments of 28 healthy male cats. These results indicate that dantrolene and prazosin may be effective in relaxing intraurethral skeletal and smooth musculature in male cats clinically afflicted with obstructive lower urinary tract disease. However, it is not certain that administration of muscle relaxants would facilitate urethral catheterization and removal of the obstruction in male cats with blockage of the lower urinary tract. Strikingly, results of this study suggest that urethral muscle spasm had a minor role in these cats.

Animals↗
PubMed1995

[Double-contrast tomographic arthrography and double-contrast CT arthrography in rotator cuff lesions].

Arthrotomography is a good method for the evaluation of incomplete or complete tears of the supraspinatus tendon, the assessment of the size of tears and the quality of the nonruptured part. CT arthrography is useful in the evaluation of the subscapularis tendon and the labral-capsular components. It depends on the clinical symptoms and the result of primary arthrography whether both methods are performed in one session or not. Based on the experience of 1200 arthro(tomo)graphy and axial CT arthrography examinations, the procedure and results in our institution are reported.

Adult↗
PubMed1994

Effect of succinylcholine, diazepam, and dantrolene on the urethral pressure profile of anesthetized, healthy, sexually intact male cats.

Effects of the neuromuscular blocking agent succinylcholine (n = 9), the centrally acting skeletal muscle relaxant diazepam (n = 11), and the directacting skeletal muscle relaxant dantrolene sodium (n = 8) on the urethral pressure profile were evaluated in anesthetized, healthy, sexually intact, adult male cats. Intravenous administration of succinylcholine (0.075 mg/kg of body weight) significantly decreased mean absolute pressure in the prostatic and post-prostatic/penile intraurethral segments by -9.5 and -6.5 mm of Hg, respectively (P = 0.0002 and P = 0.0006, respectively). Dantrolene (1.0 mg/kg, IV) significantly decreased mean prostatic and postprostatic/penile intraurethral segmental pressures by -3.5 and -2.8 mm of Hg, respectively (P = 0.005 and P = 0.0181, respectively). Diazepam (0.8 mg/kg, IV) did not significantly alter mean intraurethral segmental pressures. None of the drugs caused a change in segmental lengths of the urethra. These results indicate that skeletal muscle makes a substantial contribution to intraurethral tone in anesthetized, healthy, sexually intact male cats and that skeletal muscle relaxation may be successful in reducing prostatic and post-prostatic/penile urethral segmental tone in male cats. These results also suggest that dantrolene sodium may be valuable for the pharmacologic management of urethral disorders in male cats.

Anesthesia, General↗
PubMed1983

Renal oncocytoma: a rare renal tumor with typical angiographic features.

We report on a case of renal oncocytoma (proximal tubular adenoma) with typical vascular architecture. The vascular supply of the oncocytoma showed a 'spoke-wheel'-like pattern. The typical angiographic features may help to differentiate oncocytomas from hypernephromas and thus diagnose it as such in the preoperative period. By the use of the electron microscope some typical invasions into a small vein could be traced, therefore it seems likely that renal oncocytoma is semi-malignant. Confusion of the renal oncocytoma with a large renal cyst is a classical diagnostic error which can be fatal.

Adenoma↗