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Biomedical subjects

A Linden

Publications and source records attributed to A Linden.

86 records · Page 5Linked to original sources

Bone marrow investigation with technetium-99m microcolloid and magnetic resonance imaging in patients with malignant myelolympho-proliferative diseases.

In 63 patients with primary extramedullary malignant lymphoma or plasmacytoma, a study was performed in order to evaluate bone marrow involvement. All patients underwent a 99mTc microcolloid bone marrow whole body imaging (scintigraphy), using a gamma camera interfaced with a computer, followed by nuclear magnetic resonance bone marrow imaging (MRI), (1.5 Tesla). MR images were made of the lumbosacral region, the pelvic region, both femoral and other parts of the skeleton, according to focal lesions in the scintigraphy. A posterior iliac crest bone marrow biopsy was used as a standard reference. In the present study, both scintigraphy and MRI showed a dissiminated or focal involvement or a combination of both. In 53 of the 63 patients (84%) the results were in accordance. Pathological MR signals or pathological findings in scintigraphy did not always correspond to tumorous bone marrow involvement, and were shown to reflect reactive changes in the central part of the skeleton in combination with a periphery radionuclide extention interpreted as a periphery compensatory hematopoietic proliferation. The negative predictive value of scintigraphy and MRI was 92% and 100%, respectively. When combining the results of both examinations, the positive predictive value increased from 49% to 58%, if the bone marrow biopsy is accepted as gold standard. The results indicate that bone marrow investigation performed simultaneously using scintigraphy and MRI is superior both to the use of either of the methods alone and to the traditional iliac crest bone marrow biopsy.

Adolescent↗

Malignant lymphoma: bone marrow imaging versus biopsy.

In 107 patients with malignant Hodgkin and non-Hodgkin lymphoma, bone marrow was evaluated with scintigraphy, magnetic resonance (MR) imaging, and biopsy to detect bone marrow infiltration. Imaging and biopsy results were classified as normal (class 0), suggestive of reactive changes (class 1), or suspicious for infiltration (class 2). About one-half of biopsy and imaging results agreed completely. In patients with chronic lymphocytic leukemia, false-negative findings were frequent with both imaging techniques. Although a positive biopsy result is usually accepted as proof of bone marrow infiltration, results indicate that negative biopsy findings do not exclude tumor involvement. When suspected infiltration was found with MR imaging or scintigraphy but results were normal or suggestive of reactive changes in the first blind biopsy, repeat blind or guided biopsy helped confirm the imaging results. Autopsy findings in two patients completely confirmed previous results with MR imaging and scintigraphy, although findings at antemortem biopsy were different. Scintigraphy and MR imaging should be included routinely in the staging of malignant lymphoma as an adjunct to blind biopsy in the complete evaluation of bone marrow status.

Adolescent↗

[Renal artery stenosis: possibilities of magnetic resonance tomography].

Non-invasive detection of stenotic lesions of the renal arteries remains an important clinical problem. Recent advances in magnetic resonance angiography represent a significant progress towards achieving non-invasive diagnosis of vascular diseases. The purpose of this study was to evaluate the possibilities of assessment of renal artery stenosis with commonly available hard- and software equipment. Imaging of renal arteries was performed with a ECG-gated fast multiphase gradient echo sequence which allows production of a series of images in different heart phases. Examinations were performed in 15 healthy volunteers and in 12 patients with angiographically verified renal artery stenosis. In 10 patients additional dynamic studies with fast imaging during short breath-holding periods after administration of gadolinium-DTPA served for the assessment of renal perfusion. A superconducting system operating at 1.5 T was used to produce gradient echo sequences with small flip angles and dephasing gradients of constant amplitude. To find the optimal imaging method for depiction of the renal arteries the following parameters were systematically varied: respiratory gating, resolution, number of excitations, slice thickness, phase encoding direction, rephasing gradients, flip angle and echo time. A good visualization of the vessels was always possible and using the best parameter combination even the narrowed lumen could be assessed in some cases. With this technique or with gadolinium-enhanced dynamic studies the perfusion of the kidneys can be demonstrated. However, quantitation of the stenosis or quantitation of renal perfusion was not possible; even the depiction of the stenotic lesion was successful only in half of the cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

[Clinical and magnetic resonance tomography follow-up of surgically treated aortic isthmus stenoses in adults].

Functional impairment and local pathological changes of the aorta especially at the site of correction are well known complications after surgery for coarctation of the aorta. To evaluate the longterm results after this operation, 23 patients were assessed by physical examination, EKG, ergometry, spirometry, and magnetic resonance imaging. The postsurgical interval ranged from 1 to 28 years. The most frequent postoperative symptoms were vertigo, headache, dyspnea on exertion, cardiac arrhythmia, and left thoracic pain. Elevation of the left shoulder was found in 19 patients to be due to left lateral thoracotomy; 14 patients suffered from arterial hypertension; five additional patients showed hypertension on exertion. Magnetic resonance imaging showed pathological changes of the aorta and aortic branches in all patients. The origin of the left subclavian artery was displaced distally in eight patients. The proximal part of the left subclavian artery was dilated in 11 patients. Fourteen patients had a hypoplastic aortic arch. An aneurysm of the ascending aorta was found in five patients. Aneurysmal dilatation of the descending aorta in the region of the anastomosis was present in three patients. Restenosis of the descending aorta occurred in two patients. In conclusion, after surgery of coarctation many patients continued to have symptoms which require regular follow-up. Magnetic resonance imaging provides a complete and noninvasive examination of the heart and the great vessels and is therefore ideally suited for this purpose.

Adolescent↗

[Bone marrow scintigraphy and magnetic resonance tomography in malignant lymphomas: comparison with histologic results].

One hundred and seven patients with malignant Hodgkin and non-Hodgkin lymphoma were examined by bone marrow scintigraphy, MRI of bone marrow and bone marrow biopsy to detect bone marrow infiltration. The study included 2 patients where autopsy findings were subsequently available, 3 patients with blind rebiopsy and one patient with guided rebiopsy. The findings of bone marrow imaging and biopsy were classified as normal (grade 0), suggesting reactive changes of bone marrow (grade 1) or suspicious for infiltration (grade 2). About half of all results of biopsy and imaging methods agreed completely. There was a difference of two steps in the classification in only 2 cases (MRI) and 5 cases (scintigraphy). In patients with chronic lymphocytic leukemia false negative findings by both bone marrow imaging techniques were frequent. Unilateral blind bone marrow biopsy is usually accepted as the golden standard for the presence or absence of tumor infiltration. Although a positive biopsy result must be accepted as proof of bone marrow infiltration, our results indicate that a negative biopsy does not exclude tumor involvement. In all 4 patients with infiltration suspected on MRI or scintigraphy results but with normal findings or reactive changes in the first blind biopsy, blind rebiopsy or guided rebiopsy confirmed the results of the imaging methods. In both patients evaluated at autopsy the preceding MRI and scintigraphy results were confirmed completely, although in both of these patients antemortem biopsy had indicated different findings.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Nuclear magnetic resonance imaging of the heart.

NMR imaging is a noninvasive technique that has been shown to provide high-quality images of the heart. Due to the signal characteristics of flowing blood, inherent contrast between blood pool and myocardium is achieved without the use of contrast media. This paper briefly describes technical aspects of NMR imaging of the heart, normal cardiovascular anatomy, applications of the technique in patients with ischemic heart disease, and the potential of NMR imaging for functional studies in various forms of heart disease.

Coronary Disease↗

Plasma levels of gastrin, somatostatin, and cholecystokinin immunoreactivity during pregnancy and lactation in dogs.

Plasma levels of gastrinlike, somatostatinlike, and cholecystokininlike immunoreactivity were determined by radioimmunoassay in peripheral blood from 11 beagles during pregnancy and in response to suckling during lactation. Cholecystokinin was determined in pooled and in individual plasma samples after separation of cholecystokinin and gastrin by high-performance liquid chromatography. Gastrin and somatostatin levels were significantly increased during the 8-wk-long dog pregnancy; peak values were recorded in week 7 and week 4, respectively. The cholecystokinin level rose and peaked at week 3, and remained elevated. In response to suckling, maternal gastrin levels rose significantly when tested in week 1 and 3 of lactation. Somatostatin levels did not respond significantly to suckling, but basal levels were elevated in week 1 compared to week 3 of lactation. Cholecystokinin rose in response to suckling both in week 1 and 3 of lactation. We suggest that the increased levels of gastrointestinal hormones during pregnancy and lactation may serve to increase digestive and anabolic capacity.

Animals↗

Oxygen transport chain in double-muscled blue Belgian cattle.

The physiological peculiarities of the oxygen transport chain in double-muscled Blue Belgian cattle are described. The investigations performed at several levels of the oxygen transport chain suggest that the increased susceptibility of these cattle to stress, resulting mainly in respiratory diseases, is due to an insufficient functional reserve capacity mainly involving the pulmonary and cardiovascular systems. The resulting lack of 'functional hardiness' of the oxygen transport chain is seen in those double-muscled cattle which do not react in an appropriate or predictable way when submitted to a hostile environment.

Animals↗

Prevalence of obesity in adolescent and young adult patients with and without schizophrenia and in relationship to antipsychotic medication.

The prevalence of obesity in inpatients of a German psychiatric rehabilitation center for adolescents and young adults (mean age 19.5 years) is assessed and set into relationship to diagnosis and medication regimen. In a cross-sectional naturalistic study body weights and heights of 151 inpatients, 109 of whom presented with ICD-10 schizophrenia spectrum disorders, were measured for the calculation of body mass indices (BMI, kg/m2); current medication regimen including the duration of treatment was assessed from medical records. BMIs were plotted into gender- and age-specific BMI-percentiles representative for the German population. Among the whole study population, obesity (BMI > or =90th percentile) was apparent in 44/98 (45%) of the male and in 31/53 (59%) of the female inpatients (overall: 50%). With respect to schizophrenia spectrum disorders, 36/70 (51%) males and 25/39 (64%) females (overall: 56%) were obese in contrast to 14/42 (33%) among the individuals without schizophrenia. Set into relationship to the treatment groups, the prevalence rates of obesity were 64% in patients treated with clozapine (n=69), 56% for other atypical antipsychotics (olanzapine, sulpiride, risperidone; n=27), 30% for classic antipsychotics (haloperidol, flupentixol, perazine; n=20) and 28% for the currently drug-free group (n=25). Together with other published findings in adults, these results suggest an increased prevalence of obesity among young patients with schizophrenia and especially among patients chronically treated with atypical antipsychotics.

Adolescent↗

Effects of growth and breed on direct static measurements of chest wall compliance in cattle.

Chest wall compliance (CW) was measured in 59 conscious standing calves, aged six to 162 days, which were breathing air spontaneously through a face mask. The airways were occluded at the end of inspiration in order to elicit the Hering-Breuer reflex, the effectiveness of which was ensured by the presence of a plateau on the tracings of airway opening and oesophageal pressure (Pes). CW was measured directly from the inspired volume of the occluded breath and changes in Pes generated by the recoil of the relaxed chest wall. This airway-occlusion technique yielded reproducible CW values similar to those measured by classical invasive methods. The ratio of CW to bodyweight in the growing calves (sCW) ranged from 2.2 to 11.5 ml cmH2O-1 kg-1 and was correlated negatively with age: (log sCW = 0.91-0.003 x age, r = 0.68), the rate of decline corresponding well to the multispecies allometric growth relationship.

Abdominal Muscles↗

Study of the virulence of five strains of amyxomatous myxoma virus in crossbred New Zealand White/Californian conventional rabbits, with evidence of long-term testicular infection in recovered animals.

The virulence of five amyxomatous myxoma virus (MV) strains, the clinical and pathogenetic effects of which had been studied previously in specific pathogen-free (SPF) rabbits, was determined by inoculation of five groups of 10 crossbred New Zealand White/Californian conventional rabbits. A much more acute myxomatosis syndrome was produced in conventional rabbits than that reproduced previously in SPF animals. However, the main clinical signs were of the respiratory type. The MV strains MYX 254/95 and 801 appeared very virulent, killing all the inoculated animals. The strains MYX 217/95, MYX 555/94 and Saint Benoist were somewhat attenuated, killing only seven, six and six rabbits, respectively. Extensive lung lesions due to supervening bacterial infections were observed in 36 of the 39 rabbits that died. Lethality was found to be a better estimate of virulence than mean survival time. By 98 days after viral inoculation, all the surviving animals had completely recovered. At that time, they were immunosuppressed by treatment with adrenocorticotrophic hormone (ACTH) for 10 days to determine whether they still harboured the virus. After the ACTH treatment, eight of the 11 surviving rabbits showed clinical signs that resembled amyxomatous myxomatosis. All the virological examinations performed on naso-conjunctival exudate, on mononuclear cells, on eyelids and on ovaries remained negative but infectious virus was isolated from the testes of three of six surviving male rabbits.

Adrenocorticotropic Hormone↗

The efficacy of two vaccination schemes against experimental infection with a virulent amyxomatous or a virulent nodular myxoma virus strain.

Two types of myxomatosis vaccine are available commercially, namely, vaccine prepared from the Shope fibroma virus (SFV) and that prepared from an attenuated myxoma virus (MV) strain, e.gSG33. An experiment was designed to compare two vaccination schemes for their ability to protect rabbits against challenge with either a virulent amyxomatous MV strain or a virulent nodular MV strain. Apart from a difference in the cutaneous expression of the disease, the two challenge strains resembled each other in respect of mortality rate, naso-conjunctival shedding of virus, and tissue infection. Vaccination with SFV alone failed to prevent clinical signs, naso-conjunctival shedding or tissue infection. Vaccination with SFV followed by a booster inoculation with SG33 protected rabbits against the development of clinical signs and significantly reduced both viral shedding in naso-conjunctival exudates and viral infection of eyelids, lungs and testes; virus was, however, isolated from testes of some surviving animals.

Animals↗