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Biomedical subjects

C Zollikofer

Publications and source records attributed to C Zollikofer.

At least 19 recordsLinked to original sources
PubMed2001

Diagnosis of symptomatic intestinal metastases using transabdominal sonography and sonographically guided puncture.

OBJECTIVE. We studied the sonographic findings of symptomatic intestinal metastases and the use and safety of subsequent sonographically guided 22-gauge fine-needle aspiration or 18-gauge core biopsy. CONCLUSION. Symptomatic intestinal metastases can be diagnosed by transabdominal sonography. Extensive hypoechoic segmental bowel wall thickening with loss of stratification and intussusception can be observed. Sonographically guided fine-needle aspiration or 18-gauge core biopsy performed at the end of the examination allows definite diagnosis and is a safe procedure.

Aged↗
PubMed1997

Kissing osteochondromata leading to synostoses.

Our aim was to determine the incidence of synostoses in the bones of the lower limbs in patients with multiple cartilaginous exostosis (MCE) and use the available imaging to suggest the cause and mechanism of its development. Radiographs of the lower legs of 21 patients with MCE were reviewed. With the intention of demonstrating the exact site and extent of synostoses and other bone deformities, such as bone pressure atrophy or erosions in five patients, 8 proximal and 6 distal tibiofibular joints were examined by CT scans. No synostoses were present in 11 patients and 10 patients had 1 to 4 synostoses. Of these synostoses, 14 were localized below the knee joint and 9 above the ankle joint. A growing osteochondroma arising from tibia or fibula can cause an erosion in the contagious surface of the neighbouring bone. If facing osteochondromata are present in both bones and show an interlocking growth at abutting parts, on osseous fusion can take place with formation of a synostosis in the proximal or distal tibiofibular joint region. In adult patients with MCE and abundant osteochondromata synostoses between the neighbouring bones of the lower legs are common findings; they are always caused by coalescence of "kissing" osteochondromata.

Adolescent↗
PubMed1996

[Gastrointestinal lymphomas: ultrasonic aspects].

The importance of ultrasound for the diagnosis of gastrointestinal malignant lymphoma is explained by the fact that ultrasound is the first radiologic procedure after clinical examination which is used in diagnostic workup. The main sonographic findings are based on the radiologic appearance of the bowel wall and differentiation of its layers, starlike configuration of the narrowed echogenic center and hypoechoic wall thickening of varying extent. Typically, malignant lymphoma of the gastrointestinal wall shows as hypoechoic circumferential intestinal infiltration. Other findings such as exclusive mucosal involvement, transmural segmental infiltration or bulky tumor are rare. Characteristically, peristalsis is unaffected until a late stage in patients with gastrointestinal malignant lymphoma. These sonographic findings in patients with gastrointestinal lymphoma are not alone specific for the disease, but the combinations of various abnormalities found by ultrasound are helpful in selecting appropriate radiologic, endoscopic and biopsy procedures in the further diagnostic workup.

Gastrointestinal Neoplasms↗
PubMed1995

Optical scaling in conspecific Cataglyphis ants

This study examines the effects of body size variation on the optical properties of the compound eyes of visually guided desert ants belonging to the genus Cataglyphis. Although linear head size may vary by a factor of 2 within conspecific workers and most optical parameters change accordingly, the extent of the visual field remains constant. Comparative measurements carried out on workers of three species (C. albicans, C. bicolor and C. fortis) and on reproductive females and males of one species (C. bicolor) show that the form (size and shape) of the visual field is highly characteristic for each caste/species. A constant visual field is realised by reciprocal scaling rules for the number of ommatidia and the angular spacing of ommatidia. While larger ants have more ommatidia per compound eye, interommatidial angles are reduced accordingly, thus giving rise to a constant visual field. Among conspecific ant workers, the relationship between spatial visual acuity and eye size is similar to that found in interspecific comparisons and reflects optical constraints imposed on the design of the compound eye. Mapping of spatial visual directions onto the compound eye surface reveals a characteristic, inhomogeneous distribution of interommatidial spacing, particularly a foveal band with increased visual acuity in the vertical direction. This 'visual stretch' viewing the horizon is similar to that found in a variety of flying insects. Although, among conspecific workers, both the number of ommatidia and the interommatidial angles vary with varying head size, the overall pattern of interommatidial spacing is maintained so that corresponding positions on the compound eye of small and large individuals look in equivalent directions in space. These findings are in accordance with the observation that the shape of the compound eye surface, as expressed by the radius of curvature along cross sections, is similar in small and large ants.

Journal Article↗
PubMed1994

STEPPING PATTERNS IN ANTS - INFLUENCE OF BODY MORPHOLOGY

The locomotory behaviour of 12 ant species belonging to four different genera (Formicinae: Cataglyphis, Formica, Lasius; Myrmicinae: Myrmica) was studied by filming individuals during walking on smoked-glass plates. Subsequent multivariate analyses of walking kinematics and footfall positions showed marked species-specific as well as size-dependent differences in the locomotory behaviour. The geometric properties of the footfall patterns resulting from the alternating tripod gait scale to leg dimensions in a geometric manner. At high speed, footprint distances between succeeding tripods exceed maximum leg extension, indicating that ants are 'trotting' from one tripod to the next one with intermittent aerial phases. In at least one species (Cataglyphis bombycina), there is evidence for quadrupedal locomotion at the highest speed. The functional relationship between stride length (s, the distance between successive footprints of the same foot) and speed (v) was best described by a curvilinear model, s=avb. Exponent b ranges from 0.3 to 0.6 and reveals differences between species. Within species, exponent b is constant, whereas factor a scales to leg length. Females and males show metachronal interleg coordination patterns rather than the alternating tripod coordination pattern seen in workers of the same species.

Journal Article↗
PubMed1994

STEPPING PATTERNS IN ANTS - INFLUENCE OF LOAD

Stepping pattern geometry and walking kinematics of individual foragers of Cataglyphis fortis (Formicidae: Hymenoptera) were recorded during outward and homeward trips to and from a food source. While returning homewards, the animals were supplied with food items of defined mass (load ratio from 1.3 to 6.4) and volume. Under the influence of load, the temporal interleg coordination pattern was maintained (alternating tripod gait), but the spatial tripod pattern was modified. Tripod deformation was found to be proportional to the displacement of the centre of mass induced by the load. Stride length and stride frequency were not altered at any speed when animals carried loads compared with trips without a load. However, in order to maintain stability, mean stride length, mean speed and mean stride frequency were reduced while carrying loads.

Journal Article↗
PubMed1994

STEPPING PATTERNS IN ANTS - INFLUENCE OF SPEED AND CURVATURE

The locomotory behaviour of workers of 12 ant species belonging to four different genera (Formicinae: Cataglyphis, Formica, Lasius; Myrmicinae: Myrmica) was studied by filming individuals walking on smoked-glass plates. Subsequent multivariate analyses of footfall positions and walking kinematics revealed a set of constant features characterizing ant locomotion. The alternating tripod gait prevails over a wide range of speeds. The temporal rigidity of tripod coordination is paralleled by spatially rigid footfall patterns. Tripod geometry is preserved irrespective of speed and curvature. When walking around curves, tripods are rotated relative to the walking trajectory. Whereas stride length on the inner side of the curve is shortened, that on the outer side is independent of curvature.

Journal Article↗
PubMed1991

Accuracy of magnetic resonance imaging compared to computerized tomography and renal selective angiography in preoperatively staging renal cell carcinoma.

During 1986 and 1987, 47 patients with renal cell carcinoma were evaluated preoperatively with CT, angiography and MRI. The preoperative tumor stage (T), lymph node metastases and venous involvement determined with the three methods were compared to the operative and histopathological findings. For T stage, angiography proved less accurate (54%) than CT (64%) or MRI (63%). MRI was found to be superior to CT in assessing lymph nodes, with an overall accuracy of 89% and sensitivity of 100% compared to 77 and 60%, respectively, of CT. For venous involvement CT was overall more accurate (74%) than angiography (65%) or MRI (63%). All three methods expressed a low sensitivity (between 31 and 41%) and a high specificity (between 95 and 100%) for detecting venous involvement. The minimal advantages of MRI compared to its high cost do not justify its routine use. CT remains the method of choice in staging preoperatively renal cell carcinoma.

Angiography↗
PubMed1990

[CT diagnosis in idiopathic thrombosis of the superior mesenteric vein].

We describe three cases of idiopathic thrombosis of the superior mesenteric and portal veins, in one case with additional thrombosis of the splenic vein. All patients suffered from unspecific, slowly increasing pain. The cause of the same could be detected only via CT. After anticoagulation the patients became symptom-free. A follow-up CT showed recanalisation of the affected veins.

Adult↗
PubMed1987

[Angiographic, cavernosonographic and clinical differentiation of two forms of priapism with different prognoses].

Based on the findings upon arteriography, cavernosography and clinical features two different kinds of priapism are differentiated: Type I ("low flow priapism") is characterized by severe blood stasis within the corpora cavernosa and reduction of arterial perfusion through compression of the deep arteries of the penis. The penis is very hard and painful upon palpation. A delay of treatment over 48 hours will result in a damage of the corpora cavernosa and impotence. Type II ("high flow priapism") is characterized by arterial hyperperfusion. Outflow obstruction is absent. The penis is erected but of an elastic consistence, pain is absent. Even with a delay of treatment of up to 6 months the corpora cavernosa remain intact, normal erectile function is preserved.

Diagnosis, Differential↗
PubMed1987

Is there a relationship between gastric mucosal blood flow and stress lesions in hemorrhagic shock?

The relationship between gastric mucosal blood flow and stress lesion formation during hemorrhagic shock was studied in anesthetized dogs. Shock was induced by graded arterial bleeding. Blood flow was measured by means of the radioactive microsphere technique. Mapping of blood flow was achieved by measuring the microsphere accumulation in mucosal and muscle segments of 1-2 cm side length of the entire stomach. To produce a varying incidence of lesions the metabolic acidosis of shock was either fully corrected by intravenous sodium bicarbonate (n = 5), partially corrected (n = 4) or left uncorrected (n = 3). Mucosal lesions developed more frequently in dogs without correction than in dogs with partial correction or full correction. In 4 dogs not subjected to shock, no mucosal lesions were observed at the end of the experiments. Mucosal blood flow varied from segment to segment by a factor of up to 20, but individual segments tended to maintain their relative flow values during shock. Correction of metabolic acidosis did not significantly affect blood flow. Likewise, flow was similar in segments with and without lesions. Therefore, low regional blood flow did not predispose to the development of lesions and high flow did not prevent them. We conclude that focal mucosal ischemia alone does not lead to stress lesion formation during hemorrhagic shock.

Animals↗
PubMed1986

Treatment of Budd-Chiari syndrome by dorsocranial liver resection and direct hepatoatrial anastomosis.

Since 1980 an operation which reestablishes the blood outflow from occluded hepatic veins was performed in 7 patients with Budd-Chiari syndrome by one of us (A. Senning). Using extracorporeal circulation a dorsocranial cylindrical resection of the liver including the confluence of the occluded hepatic veins was performed by transcaval approach. The incised right atrium was sutured around the resected liver area. There was one intraoperative death. In 6 patients with a mean postoperative follow-up of 19.2 months (4-42 months), the patency of hepatoatrial anastomosis was documented by angiography or Doppler-2d-echocardiography. Four patients are free of symptoms and signs of Budd-Chiari syndrome. In one of two patients with associated cirrhosis compression of inferior vena cava reoccurred and in another patient esophageal varices persist. We conclude, that the hepatoatrial anastomosis is an effective treatment of Budd-Chiari syndrome.

Adult↗
PubMed1983

A new concept of priapism based on the results of arteriography and cavernosography.

Four patients with priapism - 3 with idiopathic and 1 with post-traumatic etiologies - were examined by arteriography and cavernosography. The findings of these examinations as well as distinct clinical findings suggest that there are 2 different types of priapism. One is characterized by severe blood stasis within the corpora cavernosa with resulting compression of the deep arteries of the penis and reduction of arterial blood flow. In the other type, arterial flow into the corpora cavernosa and drainage into the veins are substantially increased. In this type, long-standing priapism does not seem to produce fibrosis of the corpora cavernosa with resulting impotence.

Adult↗