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Biomedical subjects

J Kramer

Publications and source records attributed to J Kramer.

At least 37 records · Page 2Linked to original sources
PubMed2000

[Diagnostic imaging in femur head necrosis].

Diagnosis of avascular necrosis (AVN) of the hip has been improved by the technical progress of imaging modalities during the last decade. For a long period, only plain radiographs had been available. Scintigraphy and computed tomography contributed to differential diagnosis and early detection of bone necrosis. In the meantime, MR imaging has gained special value in the evaluation of AVN. It is now the method of choice for early detection as well as for assessment in later stage disorders. Using the ARCO system, all imaging modalities and their diagnostic viability are described. Findings regarding the different stages of AVN are correlated to tissue-specific changes.

Diagnostic Imaging↗
PubMed2000

Embryonic stem cell-derived chondrogenic differentiation in vitro: activation by BMP-2 and BMP-4.

Differentiation of mouse embryonic stem (ES) cells via embryoid bodies was established as a suitable model to study development in vitro. Here, we show that differentiation of ES cells in vitro into chondrocytes can be modulated by members of the transforming growth factor-beta family (TGF-beta(1), BMP-2 and -4). ES cell differentiation into chondrocytes was characterized by the appearance of Alcian blue-stained areas and the expression of cartilage-associated genes and proteins. Different stages of cartilage differentiation could be distinguished according to the expression pattern of the transcription factor scleraxis, and the cartilage matrix protein collagen II. The number of Alcian-blue-stained areas decreased slightly after application of TGF-beta(1), whereas BMP-2 or -4 induced chondrogenic differentiation. The inducing effect of BMP-2 was found to be dependent on the time of application, consistent with its role to recruit precursor cells to the chondrogenic fate.

Aggrecans↗
PubMed2000

Cognitive consequences and central nervous system injury following treatment for childhood leukemia.

OBJECTIVES: To determine the relationship between membrane damage and intellectual and academic abilities in children with acute lymphoblastic leukemia (ALL) and pilot test a math intervention for children with ALL who were affected. DATA SOURCES: Research studies and review articles. CONCLUSIONS: Despite the prophylactic central nervous system (CNS) treatment for long-term disease-free survival, many children with ALL subsequently experience declines in intellectual and academic skills. IMPLICATIONS FOR NURSING PRACTICE: Improving academic abilities in children who have received CNS treatment is of high priority and may have longlasting implications on quality of life.

Analysis of Variance↗
PubMed2000

Streptokinase does not activate the complement system.

Streptokinase is an extensively used thrombolytic agent. However, different preparations cause severe hypotension during therapy, partially related to the complement cascade activation. In four ischaemic stroke patients treated with Streptase, an increased level of soluble terminal complement complex (SC5b-9) was measured. In the sera of normal subjects, the increase in SC5b-9 induced by Streptase, Kabikinase and Calbiochem streptokinases was highly significant (P < 0.005). Sigma streptokinase did not activate the complement system. Sigma streptokinase analyzed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis showed a homogeneous band. The other three preparations were contaminated with albumin and other proteins. Based on our in vivo and in vitro data, we conclude that complement activation is related to contamination of different streptokinase products rather than the streptokinase itself.

Acute Disease↗
PubMed2000

Prospective randomized clinical trial of continuous passive motion after total knee arthroplasty.

The authors report the results of a prospective randomized clinical trial using continuous passive motion after total knee arthroplasty. One hundred twenty patients were assigned randomly to one treatment group: No continuous passive motion (Group I), continuous passive motion from 0 degrees to 50 degrees and increased as tolerated (Group II), and continuous passive motion from 70 degrees to 110 degrees (Group III). The continuous passive motion was initiated in the recovery room and was maintained for a maximum of 24 hours at which point all patients began identical postoperative physiotherapy regimens. Patients were assessed preoperatively, during their hospital stay, at 6 weeks, 12 weeks, 26 weeks, and 52 weeks after their surgery. There were no statistical differences between any of the treatment groups regarding cumulative analgesic requirements, range of motion at any measured interval, length of stay (Group I, 5.1 days; Group II, 5.2 days; Group III, 5 days) or Knee Society scores. The current study does not support the use of short-term continuous passive motion after total knee replacement. A standard and a high flexion continuous passive motion protocol failed to show any advantage over physiotherapy alone in the parameters evaluated.

Analgesics↗
PubMed2000

Frequencies of certain complement protein alleles and serum levels of anti-heat-shock protein antibodies in cerebrovascular diseases.

BACKGROUND AND PURPOSE: A strong correlation exists between the intensity of atherosclerotic alterations in different arteries. Marked differences exist, however, in the age and sex distribution and risk factors for coronary heart disease (CHD) and cerebrovascular disease (CVD). We therefore performed genetic and immunologic studies in patients with CVD. METHODS: We studied 292 patients with CVD (stroke or transient ischemic attack) and as control either 198 healthy blood donors and 485 healthy elderly (aged >60 years) people (genetic study) or 94 blood donors aged 45 to 60 years and 49 healthy elderly (aged >60 years) people (anti-heat-shock protein [hsp] measurements). Allele frequencies of 3 genes (C4A, C4B, and C3) encoding proteins of the complement system were determined by electrophoresis and immunofixation. Serum concentration of autoantibodies against 60-kDa heat-shock protein (anti-hsp60) was measured by the enzyme-linked immunosorbent assay method. RESULTS: Marked differences were observed between CVD patients and controls in the genetic studies. In the CVD patients aged >60 years, the frequency (11.3%) of the deficient allele of the C4B gene (C4B*Q0) was significantly (P:=0.0003) higher than that of the healthy controls (5.4%). By contrast, in the group aged 45 to 60 years, the frequency of the C4B*Q0 allele was lower in patients than in controls. Serum concentration of anti-hsp60 in the CVD patients did not differ from control values. CONCLUSIONS: In previous studies C4B*Q0 frequency was reported to be higher in CHD patients aged 45 to 60 years than in aged-matched controls. Moreover, high anti-hsp60 levels were found in CHD patients. These findings contrast with our present report of lower frequency of C4B*Q0 in CVD patients. Therefore, genetic and immunologic factors may at least partly explain the differences between the natural history and risk factors of CHD and CVD.

Cerebrovascular Disorders↗
PubMed2000

Kinematics of the hind limb in trotting horses after induced lameness of the distal intertarsal and tarsometatarsal joints and intra-articular administration of anesthetic.

OBJECTIVE: To identify hind limb and pelvic kinematic variables that change in trotting horses after induced lameness of the distal intertarsal and tarsometatarsal joints and after subsequent intra-articular administration of anesthetic. ANIMALS: 8 clinically normal adult horses. PROCEDURE: Kinematic measurements were made before and after transient endotoxin-induced lameness of the distal intertarsal and tarsometatarsal joints and after intra-articular administration of anesthetic. Fourteen displacement and joint angle (metatarsophalangeal [fetlock] and tarsal joints) measurements were made on the right hind limb, sacrum, and the right and left tubera coxae. Kinematic measurements were compared by general linear models, using a repeated measures ANOVA. Post hoc multiple comparisons between treatments were evaluated with a Fisher least squared difference test at alpha = 0.05. RESULTS: After lameness induction, fetlock and tarsal joint extension during stance decreased, fetlock joint flexion and hoof height during swing increased, limb protraction decreased, and vertical excursion of the tubera coxae became more asymmetric. After intra-articular administration of anesthetic, limb protraction returned to the degree seen before lameness, and vertical excursion of the tubera coxae became more symmetric. CONCLUSIONS AND CLINICAL RELEVANCE: Increased length of hind limb protraction and symmetry of tubera coxae vertical excursion are sensitive indicators of improvement in tarsal joint lameness. When evaluating changes in tarsal joint lameness, evaluating the horse from the side (to assess limb protraction) is as important as evaluating from the rear (to assess pelvic symmetry).

Anesthetics↗
PubMed1999

Mice lacking the basolateral Na-K-2Cl cotransporter have impaired epithelial chloride secretion and are profoundly deaf.

In chloride-secretory epithelia, the basolateral Na-K-2Cl cotransporter (NKCC1) is thought to play a major role in transepithelial Cl(-) and fluid transport. Similarly, in marginal cells of the inner ear, NKCC1 has been proposed as a component of the entry pathway for K(+) that is secreted into the endolymph, thus playing a critical role in hearing. To test these hypotheses, we generated and analyzed an NKCC1-deficient mouse. Homozygous mutant (Nkcc1(-/-)) mice exhibited growth retardation, a 28% incidence of death around the time of weaning, and mild difficulties in maintaining their balance. Mean arterial blood pressure was significantly reduced in both heterozygous and homozygous mutants, indicating an important function for NKCC1 in the maintenance of blood pressure. cAMP-induced short circuit currents, which are dependent on the CFTR Cl(-) channel, were reduced in jejunum, cecum, and trachea of Nkcc1(-/-) mice, indicating that NKCC1 contributes to cAMP-induced Cl(-) secretion. In contrast, secretion of gastric acid in adult Nkcc1(-/-) stomachs and enterotoxin-stimulated fluid secretion in the intestine of suckling Nkcc1(-/-) mice were normal. Finally, homozygous mutants were deaf, and histological analysis of the inner ear revealed a collapse of the membranous labyrinth, consistent with a critical role for NKCC1 in transepithelial K(+) movements involved in generation of the K(+)-rich endolymph and the endocochlear potential.

Animals↗
PubMed1999

[Importance of digital thoracic radiography in the diagnosis of pulmonary infiltrates in patients with bone marrow transplantation during aplasia].

PURPOSE: Evaluation of digitized chest x-ray for the detection of pulmonary infiltrations in bone marrow transplant patients during aplasia. METHODS: Digitized chest x-rays of 40 patients (21 female, 19 male) with "Fever of unknown origin" (FUO) were evaluated concerning radiological signs of pulmonary infiltrations and correlated to clinical findings, blood chemistry, microbiology and bronchoscopy. Additionally, an individual risk profile was established. RESULTS: In 11/40 patients pulmonary infiltrations were detected in digitized chest x-rays (group 1). 10/11 developed an infectious pulmonary infiltration. 29/40 patients developed no pulmonary infiltration (group 2). When fever increased for the first time (initial chest x-ray) a sensitivity, specificity, positive and negative predictive value of 46%, 86%, 56%, 81% and for the chest x-rays in progress of 61%, 79% 68% and 73% was found. C-reactive protein and temperature increase occurred statistically significantly earlier (p < 0.05) in group 1 compared to group 2. The average latency of digital chest x-rays in comparison to c-reactive protein and temperature increase was 6 days. The incidence of risk factors was significantly higher in group 1 in comparison to group 2 (p < 0.05). CONCLUSION: Digitized chest x-rays are not a reliable method for primary detection of pulmonary infiltrations after bone marrow transplantation. Individual risk factors have to be taken into consideration to indicate further diagnostic methods such as computed tomography at an earlier time.

Adult↗
PubMed1999

MR arthrography of the adult acetabular capsular-labral complex: correlation with surgery and anatomy.

OBJECTIVE: Our purpose was to describe the appearance of the acetabular capsular-labral complex on MR arthrography and to correlate this appearance with surgical findings in adult patients and with gross anatomic findings in cadavers. SUBJECTS AND METHODS: MR arthrography of the hip joint was performed in 40 patients and six cadavers. All patients underwent subsequent arthrotomy of the hip. MR arthrography consisted of a T1-weighted three-dimensional gradient-echo sequence in both the coronal oblique and sagittal oblique planes after intraarticular injection of a 2 mmol/l solution of gadopentetate dimeglumine. The normal and pathologic appearance of the capsular-labral complex was assessed, and the labra were evaluated on the basis of morphology, signal intensity, presence of a tear, and attachment to the acetabulum. MR arthrography findings were correlated with the surgical results in all patients and with the anatomic sections of the cadaveric hip joint specimens. RESULTS: MR arthrography images of the T-weighted three-dimensional gradient-echo sequences allowed visualization of the anatomic structures. The normal labrum was triangular, without any sublabral sulcus, and of homogeneous low signal intensity. A recess between the labrum and the joint capsule could be identified in instances in which no thickened labrum was present. Labral lesions included labral degeneration, a tear, or a detached labrum either with or without thickening of the labrum. The sensitivity for detection and correct staging of labral lesions with MR arthrography in the patient study was 91%; the specificity, 71%; and the accuracy, 88%. CONCLUSION: MR arthrography with T1-weighted three-dimensional gradient-echo sequences allows excellent assessment of the normal and pathologic acetabular capsular-labral complex.

Acetabulum↗
PubMed1999

Culture and characterization of equine terminal arch endothelial cells and hoof keratinocytes.

OBJECTIVES: To develop methods to isolate, culture, and characterize equine hoof endothelial cells (EC) and keratinocytes. SAMPLE POPULATION: Cells harvested from the forelimbs of 8 horses. PROCEDURE: EC were obtained via catheters placed in the palmar digital arteries of the disarticulated lower portion of the forelimbs from 4 horses that had been heparinized prior to euthanasia. Phosphate-buffered saline solution was used to remove and discard RBC from blood vessels, and collagenase was used to loosen and flush EC from the vasculature. Hoof keratinocytes were obtained from 4 recently euthanatized horses by use of dispase/trypsin dissociation of the coronary band epidermis. Use of an extracellular matrix gel as a culture flask attachment factor was important to the success of hoof keratinocyte cultures. RESULTS: EC from the palmar digital arteries were successfully cultured and characterized by in vitro morphology, uptake of a fluorescence-labeled acetylated-low density lipoprotein, and lack of expression of von Willebrand factor and smooth muscle actin. Hoof keratinocytes were characterized by morphology in culture and expression of keratin proteins, as determined by immunochemical reaction. Keratinocyte cultures were also positive for vimentin expression. CONCLUSIONS: Culture techniques to isolate and characterize hoof cells should aid investigators in their study of equine hoof pathobiologic features, especially as it relates to laminitis.

Animals↗
PubMed1998

Prolactin response to D-fenfluramine in outpatients with major depression.

There is much indirect evidence of serotonin abnormalities in patients with major depression. Unfortunately, previous reports of serotonin challenge studies in depressed patients have yielded conflicting results. In order to test the serotonin hypothesis of depression, the authors compared 20 outpatients with major depressive disorder to 20 normal control subjects using prolactin response to D-fenfluramine as a measure of central serotonergic (5-HT) functioning. Patients were free of histories of suicidal behavior and had no Axis II disorders. There were no significant differences in prolactin responses between depressed patients and control subjects to challenge with D-fenfluramine at a dose of 0.5 mg/kg. The possible implications of these findings are discussed with respect to theories regarding biological vulnerabilities to major depression.

Adult↗
PubMed1998

[MRI arthrography in labrum lesions of the hip joint. Method and diagnostic value].

Magnetic Resonance imaging with its excellent soft tissue contrast represents the method of choice for examination of intraarticular and periarticular structures of joints. However, conventional MR-imaging without intraarticular contrast application is not suitable for the diagnosis of labral lesions. MR-arthrography (MRA) of the hip clearly demonstrates labral pathology by distension of the joint space and entrance of the contrast medium into the lesion. Multiplanar 3-D-gradient echo sequences enable visualisation of the most important cranio-ventral portion of the labrum. With the MRA labral lesions can be subdivided into different, clinically relevant stages. Furthermore accompanying lesions (intra- and extraosseous ganglia, stress-bone marrow-edema) can be demonstrated. In our study including operatively verified cases, MRA showed excellent sensitivity (90%) and accuracy (91%) in detecting labral lesions. So far no complication occurred with more than 100 MRA's. Therefore this technique represents the method of choice for the radiological evaluation of labral lesions of the hip joint. In this review the technical details and results of our MRA method will be presented.

Acetabulum↗
PubMed1998

Morphological dissociation between visual pathways and cortex: MRI of visually-deprived patients with congenital peripheral blindness.

MRI was used to study possible morphological changes in the visual system in 12 patients suffering from congenital blindness of peripheral (ocular) origin. While their optical pathways showed degeneration, hypoplasia or atrophy in 7 out of 12 cases, the occipital cortex appeared normal in all cases. This dissociation between afferent pathways and the cortex is contrary to the assumption that visually deprived cortex may undergo degeneration. The finding is congruent with evidence that the occipital cortex is used for other, nonvisual functions.

Adult↗
PubMed1998

Endothelial cells cultured from human brain microvessels produce complement proteins factor H, factor B, C1 inhibitor, and C4.

The inflammatory mediators, cytokines and complement proteins are believed to regulate the sequential events during the development of lesions secondary to ischaemia and reperfusion. The endothelial cell monolayer of the brain microvasculature is the critical interface between the blood-borne mediators and brain tissue. The involvement of these cells in complement production and regulation has not been well documented. In the present study, expression of complement proteins (C1 inhibitor, factor H, factor B, C4) by cultured endothelial cells obtained from human brain microvessels has been characterized. Interferon gamma upregulates the production of all the complement factors studied. Serine proteases, plasmin and miniplasmin induce the expression of C4, decrease the level of ELISA detectable C1 inhibitor, and do not affect the production of factors H and B. These data indicate that complement proteins are expressed locally by the brain microvessels, and may modulate the inflammatory responses of brain tissue.

Brain↗
PubMed1998

Cytokine regulation of the acute-phase protein levels in multiple myeloma.

BACKGROUND: Interleukin (IL) 6 has an important role in the regulation of acute-phase proteins (APPs) during an acute-phase response. We studied IL-6 and other cytokines to determine if they regulate serum APP levels in the same way under the condition of the aberrant, long-lasting 'acute-phase response' that occurs in patients with chronic inflammation and cancer. METHODS: Serum levels of nine positive APPs [CRP, SAA, C1-INH, Bf, C5, C8, C9, alpha 1-acidic glycoprotein (AGP) and haptoglobin] and two negative APPs [transferrin and alpha 2-HS glycoprotein (AHSG)] were measured using immunochemical methods in 59 multiple myeloma patients and in 72 healthy control subjects. Serum IL-6 and tumour necrosis factor (TNF) alpha levels were determined by bioassays. RESULTS: IL-6 was negatively correlated with five out of nine (C1-INH, C8, C9, AGP and haptoglobin) positive APPs but positively correlated with C-reactive protein (CRP). When patients with high and low IL-6 serum concentration were compared, CRP levels were higher, AGP and haptoglobin levels were lower in the high- than in the low-L-6 group, whereas no significant difference between the two groups was found in levels of the other positive and negative APPs. TNF-alpha levels were negatively correlated with transferrin and AHSG levels. No difference in the levels of positive APPs was observed between patients with low and high TNF-alpha serum concentration. By contrast, levels of both transferrin and AHSG were significantly lower in the high- than in the low-TNF-alpha group. CONCLUSIONS: These findings indicate that, except for regulation of the negative APPs by TNF-alpha, the mechanism of APP regulation is different under the conditions of the short-term and the chronic, long-lasting 'acute-phase reaction'.

Acute-Phase Proteins↗