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Biomedical subjects

M Reinhardt

Publications and source records attributed to M Reinhardt.

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

First experiences in using a new ultrasound mode and ultrasound contrast agent in the diagnosis of blunt renal trauma: a feasibility study in an animal model.

RATIONALE AND OBJECTIVES: To evaluate the diagnostic value of the new ultrasound mode "wide-band harmonic" (WBH) using an ultrasound contrast agent in blunt renal trauma in an animal model. METHODS: A defined blunt renal trauma was induced in 10 rabbits according to published standards. Ultrasound (B-mode, color and power Doppler, WBH) was performed before and after trauma, with and without using a contrast agent (Levovist). Ultrasound features were compared with histologic findings. RESULTS: In 2 of the 10 rabbits, three focal renal intraparenchymal lesions with diameters ranging from 1.0 to 1.8 mm were found that could be identified only using WBH with contrast. Six of the 10 rabbits developed a subcapsular hematoma with a thickness of up to 1.5 mm, which was identified by conventional B-mode as well as WBH. Histologic workup confirmed these findings of intraparenchymal hematomas and did not reveal further lesions. CONCLUSIONS: Only 20% of the experimental subjects developed parenchymal lesions with diameters of 1.0 mm or larger. All these lesions were identified only using WBH. These results indicate the potential to use WBH plus contrast for the diagnosis of blunt renal trauma.

Animals↗
PubMed2000

[Food allergies].

Clinical aspects of food allergies in infants and children are discussed together with diagnostic procedures in order to provide for practitioners a better understanding thus allowing a good management of pediatric patients with food-related disorders.

Bronchial Spasm↗
PubMed1999

Cardiac uptake of [123I]MIBG separates Parkinson's disease from multiple system atrophy.

OBJECTIVE: To improve the differential diagnosis between patients with multiple system atrophy (MSA) and idiopathic PD (IPD) with autonomic failure. BACKGROUND: Some patients diagnosed with IPD are discovered to have alternative diseases such as MSA, despite the application of stringent diagnostic criteria. This differentiation is particularly difficult if patients with IPD also show symptoms of autonomic failure. In IPD, autonomic failure is caused by damage of the postganglionic part of the autonomic nervous system, whereas in MSA, degeneration of preganglionic and central autonomic neurons is revealed histopathologically. METHODS: Scintigraphy with [123I]metaiodobenzylguanidine (MIBG) enables the quantification of postganglionic sympathetic cardiac innervation. Fifteen patients with IPD and 5 patients with MSA underwent standard autonomic function tests and scintigraphy with MIBG. RESULTS: In all patients, cardiovascular testing showed evidence of autonomic failure of varying severity. In all patients with IPD, the heart-mediastinum (H/M) ratio of MIBG uptake was pathologically impaired, independent of duration and severity of autonomic and parkinsonian symptoms. All patients with MSA had a regular H/M ratio. Each patient could be assigned to the correct diagnostic group based on the results of the MIBG scintigraphy, even if the duration of the disease was only 2 years or less. CONCLUSIONS: This population assessment of the heart-mediastinum ratio of [123I]metaiodobenzylguanidine uptake showed a high sensitivity for the detection of autonomic involvement in patients with idiopathic IPD and also a high specificity for the discrimination between idiopathic PD and MSA.

3-Iodobenzylguanidine↗
PubMed1999

In vitro comparison of the antigen-binding and stability properties of the various molecular forms of IgA antibodies assembled and produced in CHO cells.

The hallmark of a mucosal immune response is the production of antigen-specific secretory IgA (S-IgA) antibodies in external secretions. S-IgA consists of ten polypeptides produced in two different cell lineages. The heavy and light chains in plasma cells assemble into IgA, which on association with J chain become polymerized, whereas secretory component (SC) is added during transport across the epithelium. Recombinant chimeric mouse-human monomeric, dimeric, and S-IgA antibodies have been produced in a single CHO cell sequentially transfected with expression vectors carrying three independent selective markers for chimeric heavy and light chains, human J chain, and human SC, respectively. Biochemical characterization of the various molecular forms indicates that the assembly of the various polypeptides resulted in species of the expected size and covalence. All chimeric IgA antibodies retained the antigen-binding capacity of the parent mouse IgA antibody. The resistance of S-IgA to protease-rich intestinal washes was enhanced when compared with dimeric IgA lacking associated SC. Up to 20 micrograms of recombinant S-IgA per 1 x 10(6) cells were recovered in 24 h with the best producing clones. We conclude that CHO cells programmed de novo with four different genetic elements can assemble functional chimeric S-IgA.

Animals↗
PubMed1999

Wideband harmonic imaging: a novel contrast ultrasound imaging technique.

A novel ultrasonic imaging method, wideband harmonic imaging, for nonlinear imaging of microbubble contrast agents is evaluated. In wideband harmonic mode, two pulses of alternate phase are send out. The image is then processed from the sum of both pulses, resulting in an image of nonlinear scatterers such as microbubbles. A prototype ultrasound system, Siemens Elegra, was evaluated with in vitro investigations and animal trials, using conventional, harmonic and wideband harmonic settings with the galactose based ultrasound contrast agent Levovist. Wideband harmonic imaging offers superior sensitivity for ultrasound contrast agents compared to conventional imaging and harmonic imaging. At low transmit power settings (MI 0. 1-0.5) the nonlinear response is already sufficient to generate a image of the blood pool distribution of Levovist in the rabbit kidney including the microvasculature, with clear delineation of vessels and perfused parenchyma. At high transmit amplitudes, nonlinear tissue response reduced the apparent image contrast between contrast agent and tissue. The results suggest that wideband harmonic imaging is currently the most sensitive contrast imaging technique, maintaining highest spatial resolution. This may add to image quality and offer new clinical potential for the use of ultrasound contrast agents such as Levovist.

Animals↗
PubMed1999

Bone marrow scintigraphy using technetium-99m antigranulocyte antibody in malignant lymphomas.

BACKGROUND: The purpose of this study was to elucidate the clinical reliability of immunoscintigraphy (IS) to detect infiltration of the bone marrow in patients with malignant lymphoma. PATIENTS AND METHODS: Whole body IS was performed in 103 patients with Hodgkin's disease (HD) or non-Hodgkin's lymphoma (NHL) using Tc-99m labelled anti-NCA-95 which allows visualization of the granulopoietic bone marrow. Of these, 52% were studied prior to any therapy. Findings were compared to posterior iliac crest biopsy as well as MRI and/or follow-up examination. Criteria of marrow infiltration were a positive biopsy, positive follow-up, or positive results of MRI. RESULTS: Comparison of IS and biospy revealed concordant findings in 69 and discordant findings in 34 of 103 patients. Of the 34 patients with discordant results, IS showed lesions suspicious of bone marrow infiltration in 29 patients despite normal biopsy findings. When follow-up and additional examinations were taken into consideration, 10 patients remained with probably false positive and five with false negative IS findings. IS proved to be highly sensitive and specific in patients with HD (100% and 84%, respectively) and high-grade NHL (93% and 84%, respectively). Moderate sensitivity (60%) was found in low-grade NHL. This was possibly due to false negative IS in three to five patients with chemotherapy in contrast to one of five false negative results in patients without chemotherapy. CONCLUSION: Bone marrow scintigraphy using antigranulocyte antibodies is highly sensitive in HD and high-grade NHL. Positive findings in IS subsequent to a negative biopsy should be followed by guided re-biopsy or MRI.

Adolescent↗
PubMed1999

Staging of pelvic lymph nodes in neoplasms of the bladder and prostate by positron emission tomography with 2-[(18)F]-2-deoxy-D-glucose.

OBJECTIVES: The aim of this study was to evaluate whether pelvic lymph node metastases in patients with neoplasms of the bladder or prostate can be detected applying positron emission tomography with 2-[(18)F]-2-deoxy-D-glucose (FDG-PET). METHODS: Eight patients with bladder cancer and 17 patients with prostate cancer were examined with FDG-PET before pelvic lymph node dissection. Results of PET were then compared to histology of pelvic lymph nodes obtained at surgery. RESULTS: Lymph node metastases were detected by histopathological examination in 3 patients with bladder cancer and in 6 patients with prostate cancer. At the sites with histologically proven metastases, increased FDG uptake suspicious of metastatic disease was found in 2/3 and 4/6 patients, respectively. The smallest detected metastasis was a micrometastasis with a diameter of 0.9 cm. In 3 additional patients who all had histopathologically proven micrometastases ( </=0.5 cm), FDG uptake was within the normal range. No false-positive results were obtained. CONCLUSIONS: These results suggest that FDG-PET may be a valuable diagnostic tool in the staging of pelvic lymph nodes in bladder and prostate cancer.

Aged↗
PubMed1999

Photopenic lesions in bone marrow scintigraphy using technetium-99m labeled antigranulocyte antibody without known tumour.

AIM: The purpose of this study was to elucidate the frequency of photopenic lesions in patients without known tumour disease by using bone marrow scintigraphy with Tc-99m labeled anti-NCA-95. METHODS: Whole body immunoscintigraphy (IS) was performed in 141 consecutive patients with fever of unknown origin. The age ranged between 20 and 88 years with a mean age of 57 years. None of the patients had known tumour disease. Scans were evaluated with respect to photopenic lesions and to bone marrow distribution. RESULTS: IS showed bone marrow defects in the axial skeleton in 16 patients (11%). With the help of the typical scintigraphic defect pattern, the cause of the lesions was clearly identified as degenerative changes in four patients and in one patient as due to prior sternotomy. In the remaining 11 patients the origin of the defects became evident when the case history or additional imaging was consulted. The mean age of these 16 patients was 69 years ranging from 50 to 88 years. There was an age-related frequency of defects. 10% of the patients from 50 to 59 years showed defects, 60-69 years 9%, 70-79 years 30%, and 33% of the patients from 80 to 89 years had defects. IS was not hampered by tracer uptake to liver or spleen in 93 patients. Left caudal ribs were obscured in 48 patients with intense tracer uptake to the spleen. No or markedly reduced tracer uptake was found in caput humeri and caput femori in 94 and 82 patients, respectively. Patchy tracer uptake to the bone marrow of the limbs was seen in 13/62 patients showing marrow expansion in the lower limbs and 14/55 with marrow expansion in the upper limbs. The patchy pattern was asymmetric in 12 of these patients. CONCLUSION: The results of the present study reveal that using Tc-99m NCA-95, photopenic lesions of the bone marrow are rarely seen in patients without known malignant disease. The occurrence of benign lesions is age-related. The benign cause of the lesion was obvious from location and pattern of the lesion in about 30% of the cases. Evaluation of lesions in the upper and lower limbs may be hindered due to physiological variation of marrow distribution. Nevertheless, IS appears to be well-suited for the detection and localization of bone marrow metastases.

Adult↗
PubMed1999

Quantification of glucose transport and phosphorylation in human skeletal muscle using FDG PET.

UNLABELLED: PET with 2-[18F]-fluoro-2-deoxy-D-glucose (FDG) is used for quantifying glucose metabolism in brain and myocardium in vivo. We developed and validated a similar procedure for the quantification of the two initial steps of glucose metabolism in skeletal muscle in vivo. METHODS: The measurement protocol was first optimized by computer simulations. In addition to the accuracy in sampling plasma input and tissue time-activity curves, precise determination of the fractional blood volume, that is, the extracellular tissue volume fraction, plays a key role in correctness of the determined model constants. The optimized protocol was subsequently used to estimate transmembrane muscular glucose transport and hexokinase activity in six human subjects with normal or altered glucose utilization. PET was performed during the steady state of an euglycemic hyperinsulinemic clamp. RESULTS: A three-compartment model provides a better description of the experimental data than a two- or four-compartment model. Glucose clearance from the extracellular compartment into the skeletal muscle cell (K1) ranges from 0.024 to 0.093 mL/g/min. The intracellular glucose phosphorylation rate (k3) varies between 0.030 and 0.142 min(-1). The regional muscular glucose utilization, as calculated from the determined model parameters, lies between 10.7 and 83.3 micromol/kg/min and correlates with the whole-body glucose utilization as independently determined (R2 = 0.83; P < or = 0.01). CONCLUSION: We demonstrate by computer simulations that a three-compartment model can be used to characterize the first two steps of glucose metabolism in skeletal muscle. An optimized measurement protocol is developed and applied to experimental data. This experimental approach should be appropriate to test whether glucose transport or hexokinase activity is altered in disorders of muscular glucose utilization.

Adult↗
PubMed1998

[Positron emission tomography with [18 F]-2-fluoro-2-deoxy-D-glucose (18FDG-PET) in diagnosis of retroperitoneal lymph node metastases of testicular tumors].

In 1991, this prospectively designed study was started to assess the potentials of positron emission tomography with 18FDG in the diagnostic workup for the detection of lymph node metastases in testicular cancer, since there were no data available concerning this subject at this time. In 54 patients (27 patients with pure seminoma, 27 patients with non-seminomatous tumors) 18FDG-PET results were compared with the findings obtained with abdominal computed tomography, serum level of tumor markers (AFP, beta-HCG), and the histopathological findings after primary or post-chemotherapy retroperitoneal lymph node dissection. In 21 patients with pure seminoma (clinical stage I according to the Lugano classification) 18FDG-PET results were identical with those of the abdominal computed tomography, so PET does not add relevant informations in this group of patients. In 7 patients presenting with non-seminomatous testicular cancer (stage I), PET was not able to detect the existing micrometastases in 4 patients. In 1/7 case PET examination showed a suspicious focal lesion, this lymph node had 2 micrometastases within inflammatory changes. In 1/7 patient 18FDG-PET definitely revealed metastatic lesions, while the CT scans where judged to be unobtrusive and tumor marker levels were within the normal range. In the 4 patients with pure seminomas stage II B and II C (N = 6), that have undergone retroperitoneal lymph node dissection following chemotherapy, 18FDG-PET correctly predicted absence of tumor in 3 out of these 4, and in 1/4 patient the benign nature of a persistent large tumor after two cycles of polychemotherapy was correctly identified which eventually turned out to be a ganglioneuroma. This lesion falsely was classified as malignant tumor with abdominal computed tomography, and in 2/4 patients post-chemotherapy residual retroperitoneal lesions in the CT scans could not be assessed exactly whether or not malignant tumor was present. In 20 patients presenting with non-seminomatous testicular cancer (stage II and III) 18FDG-PET was able to demonstrate therapeutic effects of chemotherapy by showing decreasing tracer activity in those regions, that had hypermetabolic foci prior to chemotherapy. It became evident in testicular cancer that there is a single entity which is not characterized by increased glucose metabolism, the mature teratoma. In lesions detected by abdominal computed tomography which do not present increased 18FDG uptake, mature teratoma as well as scar/necrosis or rare other tumors with normal glucose metabolism can be supposed, but additional characteristics based on different 18FDG uptake were not observed. In 1/20 case post-chemotherapy PET scan detected a hypermetabolic lesion, which was suspicious for metastatic spread, but in the histopathological examination this lesion was identified as inflammatory tissue reaction. Based on the data reported here in 18FDG-PET cannot be considered a standard diagnostic tool in the staging examinations in testicular cancer. It is of clinical relevance in patients who present residual tumor after chemotherapy. In this situation 18FDG-PET is helpful in deciding whether or not a residual mass post-chemotherapy contains active tumor. 18FDG-PET can not replace retroperitoneal lymph node dissection for staging purposes.

Adult↗
PubMed1998

Impaired cardiac uptake of meta-[123I]iodobenzylguanidine in Parkinson's disease with autonomic failure.

OBJECTIVE: To selectively investigate postganglionic sympathetic cardiac neurons in patients with Parkinson's disease and autonomic failure. MATERIAL AND METHODS: Metaiodobenzylguanidine (MIBG) is a pharmacologically inactive analogue of noradrenaline, which is similarly metabolized in noradrenergic neurons. Therefore the uptake of radiolabelled MIBG represents not only the localization of postganglionic sympathetic neurons but also their functional integrity. Ten patients with Parkinson's disease and autonomic failure underwent standardized autonomic testing, assessment of catecholamine plasma levels and scintigraphy with [123I]MIBG. RESULTS: The cardiac uptake of MIBG, as demonstrated by the heart/mediastinum ratio, was significantly lower in patients in comparison with controls. Scintigraphy with MIBG allowed the selective in-vivo investigation of postganglionic sympathetic cardiac efferents in patients with autonomic failure, a procedure which was previously confined to post-mortem examination. CONCLUSION: These findings point to a relevant postganglionic pattern of involvement of the autonomic nervous system (ANS) in Parkinson's disease and autonomic failure.

3-Iodobenzylguanidine↗
PubMed1998

Cerebral perfusion during transient global amnesia: findings with HMPAO SPECT.

UNLABELLED: The aim of this study was to investigate the pattern of regional cerebral blood flow changes associated with transient global amnesia (TGA). METHODS: HMPAO SPECT was performed in six consecutive patients during the acute phase of TGA. A follow-up SPECT was performed 3-20 wk later in four of the six patients. Semiquantitative analysis of 14 regions of interest, including the basal ganglia and the basal section of the temporal lobes, was performed by comparing patient data with control data obtained from a matched group of healthy subjects. RESULTS: During TGA, unilateral or bilateral hypoperfusion of the temporo-basal region was observed in four patients. Variable hypoperfusion of further cortical areas was observed in five patients. Two patients who exhibited the most marked cortical hypoperfusion also showed striatal and thalamic hypoperfusion. These changes were normalized in the control studies obtained in four patients. CONCLUSION: It remains unclear whether hypoperfusion during TGA represents a primary feature or a sequel of regional brain hypometabolism. Because hypoperfusion is not confined to the temporo-basal region or to the territory of the posterior cerebral artery, it is suggested that the origin of TGA-related changes lies at the level of subcortical structures that project diffusely to the cerebral cortex.

Acute Disease↗
PubMed1998

[First results of radioiodine therapy of multifocal and disseminated thyroid gland autonomy and use of a TcTUs-adapted dose concept].

AIM: The presented study examines prospectively the efficiency of a dose concept for radioiodine therapy (RIT) adapted to the pretherapeutic 99mTc-pertechnetate thyroid uptake under suppression (TcTUs) in patients with multifocal (MFA) and disseminated (DISA) autonomy. This concept considers the total thyroid as target volume and uses target doses from 150 Gy to 300 Gy according to the TcTUs, which is as a measure for the "autonomous volume" of the thyroid. METHODS: The data of 75 patients (54 female, 21 male; age 71 +/- 9 years) with MFA of DISA were evaluated. RIT was performed on patients presenting with normal values for free triiodothyronine and thyroxine and endogenous suppression of the basal thyrotropin (TSH). The following target dose were used for a TcTUs of 1.5-2.5% 150 Gy, for 2.51-3.5% 200 Gy, for 3.51-4.5% 250 Gy, and for > 4.5% 300 Gy. The radiation dose to be administered was calculated using a modified Marinelli formula. The therapy was considered as successful. When the basal TSH was above 0.5 mU/l and autonomous areas had disappeared in thyroid scintigraphy or the TcTU was below 1.5%, respectively. The average follow-up period was 8 +/- 4 months. RESULTS: The success rates average to 92%. Only in one case a subsequent subclinical hypothyroidism and in a further case an immunogenic hyperthyroidism occurred. CONCLUSION: The presented data indicate that even patients with a marked autonomy (TcTUs > 3.5%) can thus expected to be cured by of a one time therapy with success rate of over 90% using the presented dose concept. The rate of early hypothyroidism can altogether be estimated as very low.

Aged↗
PubMed1997

Delineation of experimental liver tumors in rabbits by a new ultrasound contrast agent and stimulated acoustic emission.

RATIONALE AND OBJECTIVES: A new ultrasound contrast agent (SH U 563 A), consisting of hollow biodegradable polymeric microparticles, and a new imaging technique (stimulated acoustic emission) were used for delineation of experimental liver tumors. After intravenous injection, these microparticles are phagocytosed by cells of the reticuloendothelial system (RES) and create a color-coded signal using color Doppler. Because of the different distribution of phagocytic cells in healthy liver tissue and tumors, the delineation of focal lesions was to be tested. METHODS: Sixteen rabbits with VX2 liver tumors received doses of 0.15-mL SH U 563 A per kilogram of body weight intravenously. Liver investigations (UM9, HD1, L10.5, ATL, Bothell, USA) were performed in vivo before and after SH U 563 A application in B and color Doppler modes. Additionally, the liver and spleen of these rabbits were examined ex vivo in color Doppler. The sonographic diagnosis was confirmed by pathology. RESULTS: After application of SH U 563 A, the healthy liver tissue of all rabbits was characterized by a typical mosaic color pattern in vivo and ex vivo, using color Doppler. Entire VX2 liver tumors were detectable exclusively in color Doppler after SH U 563 A application. This was possible in 14 of 16 rabbits in vivo and in all 16 livers ex vivo. Furthermore, all ex vivo investigated spleens were color enhanced homogeneously. Sonographic diagnoses were in accordance with pathologic findings. CONCLUSIONS: SH U 563 A, combined with stimulated acoustic emission, provides potential for delineation of small isoechogenic liver lesions by sonography.

Animals↗