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Biomedical subjects

C Stoupis

Publications and source records attributed to C Stoupis.

At least 19 recordsLinked to original sources
PubMed2002

[Canine panosteitis: an idiopathic bone disease investigated in the light of a new hypothesis concerning pathogenesis. Part 1: Clinical and diagnostic aspects].

Panosteitis, an idiopathic bone disease of young dogs, was investigated in the light of a new, empirically based hypothesis governing its pathogenesis. Extensive clinical observations suggest a close relationship between the incidence of this disease and the commercialization of various protein-rich, high-calorie dog foods. The theory of an "osseous compartment syndrome" provides a hypothetical pathogenesis, which corroborates this findings. An excessive accumulation of protein causes intraosseous edema due to its osmotic effects. Because bone is a rigid compartment, this leads to an increase in intramedullary pressure and compression of blood vessels. Subsequent osseous ischemia leads to a deficient metabolic state (decreased oxygenation, inadequate influx of nutritive substances, local acidosis, decreased removal of metabolites, disruption of local biochemical processes, etc.), and a vicious circle is created due to the resulting local inflammation. The disease is aggravated by increased metabolism due to excessive physical activity. Within the context of a pilot study, clinical, radiographic, scintigraphic and thermographic examinations and a therapeutic trial with benzopyron were carried out. In addition, more modern investigative tools, including osteomyelography, magnetic resonance tomography and intraosseous pressure measurements were used to provide objective data concerning the pathogenesis of panosteitis. In most cases, clinical remission was seen within days of monotherapy with the proteolytic substance, benzopyron (Cumartrin). This finding appears to corroborate our hypothesis.

Animal Feed↗
PubMed2002

Malignant melanoma metastatic to the gastrointestinal tract.

A retrospective study of 385 melanoma patients was performed, with the goal of evaluating the clinical characteristics, the role of imaging and the impact of treatment on patients with gastrointestinal (GI) metastases. Eighteen patients (4.7%) had GI tract metastases. In 50% the primary lesion was on the lower extremities (P< 0.01), while 61.1% had nodular melanomas (P < 0.01). Imaging and/or endoscopy were undertaken in 72.2% of the patients, yielding positive results in all. Eight patients underwent curative surgery, two received no treatment, while the remaining eight patients had chemotherapy or immunochemotherapy. Long-term palliation was offered to 87.5% of the surgical patients compared with 50% of the patients treated medically. Median survival in the patients treated with surgery was 47.5 months compared with 5.8 months in the medical group (P < 0.01). GI tract metastases were more common in patients with nodular melanoma of the lower extremities. To our knowledge, this is the first study correlating the primary lesion's characteristics with the development of GI tract metastases. Imaging is effective in the diagnosis of GI tract involvement. Melanoma patients with GI tract metastases can benefit from palliation by surgical resection. Survival is improved when such patients are treated with curative surgery.

Adolescent↗
PubMed2001

Impact of fundus rotation gastroplasty on anastomotic complications after cervical and thoracic oesophagogastrostomies: a prospective non-randomised study.

OBJECTIVE: To find out the leak rate after cervical or thoracic anastomoses of oesophagus to fundus rotation gastric tubes after oesophagectomy. DESIGN: Prospective non-randomised study. SETTING: University hospital. Switzerland. SUBJECTS: 95 patients, of whom 62 had cervical and 33 thoracic anastomoses. INTERVENTIONS: Anastomoses were hand sewn in two layers between oesophagus and a gastric tube, that was elongated by 30% by a stapled fundus rotation gastroplasty. Anastomotic patency was studied clinically and radiographically between the 5th and 7th postoperative days. RESULTS: Five of the 62 patients had a clinical or radiological anastomotic leak (8%) in the neck and 2 of the 33 patients in the thorax (6%). Six patients died, one death being the result of a leak. CONCLUSION: Length and blood supply of fundus rotation gastroplasty tubes allows for safe anastomoses at thoracic and cervical levels.

Adult↗
PubMed1999

Microcirculation in chronic alcoholic pancreatitis: a laser Doppler flow study.

Experimental chronic pancreatitis is associated with microcirculatory disturbances but can also be induced or aggravated by perfusion changes. Microcirculatory alterations in human chronic pancreatitis are poorly defined. In this clinical study we investigated pancreatic microcirculation in the normal human pancreas and in chronic pancreatitis by laser Doppler flowmetry. Laparotomy was performed on 13 patients with nonpancreatic disease and on nine patients with chronic alcoholic pancreatitis for pancreatic head resection. Blood flow was measured over the pancreatic head, the uncinate process, over the mesenteric vein, the pancreatic corpus, and over the pancreatic tail by laser Doppler flowmetry. Blood flow was highest in the head of a normal pancreas with a mean of 436 +/- 34 perfusion units (PU), 399 +/- 43 PU in the uncinate process, 286 +/- 30 PU in the pancreatic corpus, and 351 +/- 46 PU in the tail of the pancreas. In the normal pancreas, lowest blood flow was measured over the mesenteric vein (228 +/- 23 PU). In chronic pancreatitis, blood flow in the pancreas was significantly decreased across the whole pancreas (p < 0.01). Furthermore flow-wave pattern was altered in chronic pancreatitis as compared with the normal pancreas. The normal human pancreas has a spatial variation in blood flow, correlating with the pancreatic arterial blood supply. In the chronically inflamed human pancreas, blood flow is significantly diminished, with a lower flow toward the pancreatic head.

Blood Flow Velocity↗
PubMed1999

A novel colon pouch and its comparison with a straight coloanal and colon J-pouch--anal anastomosis: preliminary results in pigs.

BACKGROUND: Early functional results after complete rectal resection and straight coloanal anastomosis are often characterized by frequent bowel movements, urgency, and varying degrees of stool incontinence. The formation of a colon reservoir improves early and long-term function. We evaluated the feasibility of a novel, modified design of a colon pouch--anal anastomosis in pigs and compared the results with those of pigs with straight coloanal anastomosis and colon J-pouch. METHODS: Complete rectal resection followed by either a straight coloanal anastomosis, a colon J-pouch, or a novel design of a colon pouch was performed in equal numbers in 15 pigs. By transversely closing a longitudinal colotomy, the new, technically simpler pouch is formed. Functional results were assessed during a period of 6 weeks. RESULTS: All 15 procedures were successful. The novel colon pouch required less surgical time than the colon J-pouch, and the formation of the pouches did not reduce tissue perfusion as assessed by laser Doppler flowmetry. The mean volume of the novel colon pouch was significantly smaller than the volume of the colon J-pouch. All the pigs with the novel colon pouch had normal stool frequency and consistency during a period of 6 weeks. In the group with straight coloanal anastomosis, two pigs had increased frequency of defecation, one pig showed signs of urgency and perianal dermatitis, and three had substantially reduced stool consistency. Of the four pigs with colon J-pouch, three had signs of impaired pouch evacuation and two had reduced stool frequency. CONCLUSIONS: The novel colon pouch is feasible in pigs and technically simpler than the colon J-pouch. These preliminary results indicate that the smaller capacity of this pouch seems sufficient for normal defecation. Its short-term functional results were better than those after reconstruction with a colon J-pouch or a straight coloanal anastomosis.

Anal Canal↗
PubMed1998

Biliary cystadenocarcinoma of the liver: the need for complete resection.

We report on a patient with biliary cystadenocarcinoma and review 112 previously published cases of this rare cystic hepatic neoplasm. This tumour mainly occurs in women at a ratio of 62% (female) to 38% (male), and at an average age of 56.2 years (range 18-88 years). The origin of these neoplasms is intrahepatic in 97% of cases and extrahepatic in the remaining 3%. The clinical symptoms are nonspecific and are not distinctive from benign cystic liver lesions unless invasive growth of the tumour occurs or distant metastases are present. Sonography and computed tomography (CT), as well as magnetic resonance imaging (MRI) demonstrate the multilocular nature of the tumour with septal or mural nodules. Discrete soft tissue masses, thick and coarse calcifications and varying density on CT or intensity on MRI within the loculi are additional non-specific imaging findings. The best therapeutic result with a 5-year survival rate of 100% and a recurrence rate of only 13% was achieved by complete excision (n = 16). Surgical removal of the tumour by complete excision is, therefore, the treatment of choice for biliary cystadenocarcinomas.

Aged↗
PubMed1998

Role of thromboxane and leukotriene B4 in patients with acute respiratory distress syndrome after oesophagectomy.

We have studied prospectively the clinical course and serum concentrations of thromboxane B2 (TxB2) and leukotriene B4 (LTB4) in patients developing adult respiratory distress syndrome (ARDS) after oesophagectomy. The clinical course was assessed according to a validated ARDS score, and intra- and postoperative measurements of TxB2 and LTB4 in pre- and post-pulmonary blood were performed in 18 patients undergoing oesophagectomy for oesophageal carcinoma and 11 control patients undergoing thoracotomy and pulmonary resection. Six of 18 patients undergoing oesophagectomy, but no control patient, developed ARDS. The ARDS score was highest on day 8 after operation. Only patients with ARDS had a significant postoperative increase in post-pulmonary, but not pre-pulmonary, TxB2 concentrations (P < 0.05 vs patients without ARDS). This study provides evidence that TxA2, originating from the lungs, was associated with the development of ARDS after oesophageal resection. In view of the high incidence of ARDS after oesophagectomy (10-30%), prophylactic treatment of patients undergoing oesophageal resection with clinically applicable thromboxane synthetase inhibitors may be warranted.

Adult↗
PubMed1997

Reliability of pedicle screw assessment utilizing plain radiographs versus CT reconstruction.

The position of 119 pedicle screws was assessed on plain antero-posterior and lateral radiographs taken immediately post-operatively and at 3 months' follow-up. The readings of five independent observers were compared with the "gold standard" of CT reconstructions. The position of only 41% of implants (range 14%-56%) was assessed correctly on the plain radiographs (47% on follow-up films). Two-thirds of CT-detectable perforations were missed. As shown with perforations of the anterior cortex, detectability increased significantly with magnitude of perforation. No specifically difficult anatomic level or direction of malplacement could be identified. Interobserver variation was considerable. Plain radiographs were shown to be of limited use in assessing the position of pedicle screws.

Bone Screws↗
PubMed1997

In vivo animal tests of an artifact-free contrast agent for gastrointestinal MRI.

A variety of shortcomings are associated with most currently used gastrointestinal contrast agents for magnetic resonance imaging (MRI). Artifacts resulting from peristalsis and other motions in the abdominal region are produced by many positive contrast agents (which increase signal intensity). Although this is not a problem for negative contrast agents (which decrease signal intensity), some negative contrast agents produce magnetic susceptibility artifacts that are especially pronounced at high field strength and with gradient echo pulse sequences. These susceptibility artifacts are produced by both paramagnetic and diamagnetic agents. It has been demonstrated in phantoms, however, that susceptibility matching can be used to produce contrast agents with desirable relaxation and contrast properties but without deleterious susceptibility artifacts. We now report results of animal tests of such an oral contrast agent, consisting of a suspension of superparamagnetic iron oxide particles and diamagnetic barium sulfate particles, compared to individual suspensions of the iron oxide and of the barium sulfate. Iron oxide was the least effective and the matched susceptibility mixture was the most effective for the intestine, which has traditionally been the most difficult region of the GI tract to visualize clearly. Matched susceptibility mixtures, which are inherently able to yield images free of susceptibility artifacts without compromising contrast, show promise of being improved oral negative contrast agents for use in gastrointestinal MRI.

Administration, Oral↗
PubMed1996

Superparamagnetic iron oxide (SPIO) as an oral contrast agent in gastrointestinal (GI) magnetic resonance imaging (MRI): comparison with state-of-the-art computed tomography (CT).

This study was conducted to compare the sensitivity and specificity of abdominal magnetic resonance imaging using oral superparamagnetic iron oxide with oral contrast-enhanced computed tomography in the detection of GI pathology. Overall sensitivity was calculated to be 83% for OECT compared to 67% by SPIO MRI. Specificity for OECT was 68% compared to 89% for SPIO MRI. The results from imaging with superparamagnetic iron oxide and imaging with oral contrast-enhanced computed tomography were in agreement in 14 subjects who had normal gastrointestinal tracts. In the remaining 16 patients, eight pathologic entities were detected by both modalities whereas 15 abnormalities were seen by only one modality. Superparamagnetic iron oxide magnetic resonance imaging was helpful in discriminating normal bowel from solid lesions and in detecting subtle gastrointestinal tract mass effect. In 30 consecutively studied patients suspected of having GI pathology, OECT was more sensitive than SPIO MRI in detecting abdominal pathology. Conversely, SPIO MRI was more specific than OECT.

Administration, Oral↗
PubMed1995

Neoplastic invasion of the laryngeal cartilage: comparison of MR imaging and CT with histopathologic correlation.

PURPOSE: To compare the usefulness of computed tomography (CT) and gadolinium-enhanced magnetic resonance (MR) imaging in the detection of neoplastic invasion of laryngeal cartilage. MATERIALS AND METHODS: In a prospective study, 53 patients with carcinoma of the larynx or piriform sinus underwent CT and MR imaging before total or partial laryngectomy. The findings at imaging and pathologic examination were compared. RESULTS: At histologic examination, neoplastic invasion of cartilage was present in 34 patients and absent in 19. MR imaging was more sensitive than CT (89% vs 66%; P = .001). Inflammatory changes and fibrosis, however, were indistinguishable from tumor on MR images, resulting in overestimation of neoplastic invasion in a large number of patients. Therefore, MR imaging was less specific than CT (84% vs 94%; P = .004). CONCLUSION: MR imaging is more sensitive than CT in detecting neoplastic invasion of cartilage, but the inability to differentiate between nonneoplastic inflammatory changes and tumor with MR imaging leads to overestimation of neoplastic invasion.

Carcinoma, Squamous Cell↗
PubMed1995

Diagnosis of renal artery stenosis: feasibility of combining MR angiography, MR renography, and gadopentetate-based measurements of glomerular filtration rate.

OBJECTIVE: Our aim was to evaluate the feasibility of combining in a single test (1) structural evaluation of renal arteries with MR angiography, (2) functional evaluation of global glomerular filtration rates calculated on the basis of plasma disappearance of gadopentetate dimeglumine, and (3) renographic analysis of individual kidneys based on the dynamic changes in signal intensity that occur after administration of gadopentetate dimeglumine. SUBJECTS AND METHODS: We used unenhanced MR angiography to measure patency of the renal arteries in 10 healthy volunteers and in 10 patients with renal artery stenosis. Calculations of global glomerular filtration rate were based on measurements of plasma disappearance of gadopentetate dimeglumine as shown by MR relaxometry. For renography with gadopentetate dimeglumine, we generated curves that showed changes in signal intensity in both kidneys over time; intrarenal kinetics were studied by measuring the time of arrival of gadopentetate dimeglumine in the cortex and outer medulla of the kidney. Conventional angiograms, measurements of global glomerular filtration rate based on plasma disappearance of 99mTc-DTPA, and 99mTc-DTPA renograms were used as reference standards. We compared the two different methods of determining global glomerular filtration rates by computing the correlation coefficient of the linear regression of rates derived from studies with gadopentetate dimeglumine versus rates derived from studies with 99mTc-DTPA. RESULTS: In all volunteers, renal arteries were well visualized, and global glomerular filtration rates based on plasma clearance of gadopentetate dimeglumine were normal. In nine of 10 patients, correlation was good between findings on MR angiograms and findings on conventional arteriograms. Finding were discordant in one patient because the patient moved during the MR angiography. For all six patients studied, correlation was good between measurements of global glomerular filtration rates based on plasma clearance of gadopentetate dimeglumine and those based on clearance of 99mTc-DTPA (r = 98%). CONCLUSION: Our results suggest the potential of magnetic resonance for a comprehensive approach for detection of renal artery stenosis. This novel approach provides structural evaluation of renal arteries with unenhanced MR angiography. MR renography is done and global glomerular filtration rates are determined by using MR relaxometry after injection of contrast material. Corticomedullary transit times can be determined on the basis of the dynamic changes in signal intensity that occur after administration of gadopentetate dimeglumine.

Adult↗
PubMed1994

Primary liver neoplasms: MR imaging with pathologic correlation.

Magnetic resonance (MR) imaging is a powerful tool in the evaluation of primary liver neoplasms. Determination of tumor extent and tissue characterization is provided with standard spin-echo T1- and T2-weighted imaging and is enhanced by the application of advanced sequences such as gradient-echo, fast spin-echo, and fat suppression techniques. Intravenously administered contrast agents, such as gadopentetate dimeglumine and superparamagnetic iron oxide, provide additional opportunities for lesion characterization. Knowledge of the underlying gross and microscopic pathologic features of primary hepatic neoplasms leads to a better understanding of their often complicated MR imaging appearances. The authors correlate the key pathologic features with the most significant MR imaging findings of primary benign and malignant liver neoplasms, including hemangioma, focal nodular hyperplasia, hepatocellular adenoma, infantile hemangioendothelioma, mesenchymal hamartoma, hepatocellular carcinoma, fibrolamellar carcinoma, intrahepatic cholangiocarcinoma, biliary cystadenoma and cystadenocarcinoma, angiosarcoma, hepatoblastoma, and undifferentiated embryonal sarcoma.

Adenoma, Liver Cell↗
PubMed1994

Bubbles in the belly: imaging of cystic mesenteric or omental masses.

The purpose of this article is to familiarize radiologists with the spectrum of "bubbles in the belly," including the current histologic classification of mesenteric or omental cysts. Although mesenteric and omental cystic masses are uncommon lesions, radiologists should be familiar with them as well as with other anomalies that can manifest as these cysts. The first step in diagnosing a cystic abdominal mass is to determine the organ from which the mass originates. The most common type of mesenteric or omental cyst is lymphangioma, but other types encountered include the enteric duplication cyst, the enteric cyst, the mesothelial cyst, and the nonpancreatic pseudocyst. Other cystic lesions that may be located in the mesentery or omentum include cystic mesothelioma, cystic spindle cell tumor, and cystic teratoma. Because of the overlap in imaging features of mesenteric or omental cysts and other cystic masses, histologic analysis is usually necessary to establish a diagnosis. The major role of the radiologist is to document the cystic nature of these abdominal masses and their mesenteric or omental origin.

Cysts↗
PubMed1993

A potentially artifact-free oral contrast agent for gastrointestinal MRI.

The combination of diamagnetic barium sulfate and superparamagnetic iron oxide (SPIO) in one suspension produces a macroscopic cancellation of positive and negative magnetic susceptibility components that can potentially eliminate susceptibility artifacts even with gradient echo pulse sequences. The relaxation properties that make the SPIO suspension a useful negative contrast agent are retained.

Administration, Oral↗
PubMed1992

Alterations in hepatic fructose metabolism in cirrhotic patients demonstrated by dynamic 31phosphorus spectroscopy.

Quantitative liver function tests are based on the clearance concept and measure the plasma disappearance of a test compound such as galactose. Metabolism is inferred to be predominantly hepatic, and usually no knowledge is obtained of the true time course of metabolite formation. Dynamic 31phosphorus magnetic resonance spectroscopy after intravenous administration of fructose directly measures hepatic sugar metabolism. To determine the feasibility and the utility of 31P magnetic resonance spectroscopy, we studied the responses of six healthy subjects and nine patients with nonalcoholic cirrhosis to a fructose load. Results were related to the impairment of hepatic function assessed by the galactose-elimination capacity test. Liver spectra were acquired in a 1.5 T whole-body nuclear magnetic resonance unit with a surface coil (9-cm diameter) placed ventrally on the liver; the one-dimensional chemical-shift imaging technique was used to obtain spectra from tissue slices parallel to the surface coil. After a basal spectrum had been obtained, fructose (250 mg/kg) was injected intravenously, and further spectra were collected sequentially every 6 min for 1 hr. Formation of monophosphate esters (9% +/- 5% vs. 20% +/- 8% of total area; p less than 0.01) and utilization of inorganic phosphate (5% +/- 4% vs. 11% +/- 3% of total area; p less than 0.005) were markedly decreased in cirrhotic patients. These measures correlated with the severity of the impairment of liver function measured by the galactose-elimination capacity (r = 0.53 to 0.69; p less than 0.05). We conclude that dynamic 31P magnetic resonance spectroscopy is a safe, clinically feasible test that allows detailed insights into biochemical events in liver disease.

Adenosine Triphosphate↗