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Biomedical subjects

H M Klein

Publications and source records attributed to H M Klein.

At least 19 recordsLinked to original sources
PubMed2007

Intramyocardial implantation of CD133+ stem cells improved cardiac function without bypass surgery.

INTRODUCTION: Cell transplantation for myocardial regeneration has been shown to have beneficial effects on cardiac function after myocardial infarction. Most clinical studies of intramyocardial cell transplantation were performed in combination with coronary artery bypass grafting (CABG). The contribution of implanted stem cells could yet not be clearly distinguished from the effect of the CABG surgery. Our current phase 1 clinical study has focused on the safety and feasibility of CD133+-enriched stem cell transplantation without CABG and its potential beneficial effect on cardiac function. METHOD AND RESULTS: Ten patients with end-stage chronic ischemic cardiomyopathy (ejection fraction <22%) were enrolled in the study. Bone marrow (up to 380 mL) was harvested from the iliac crest. CD133+ cells were purified from bone marrow cells using the CliniMACS device with purities up to 99%. Autologous bone marrow CD133+ cells (1.5-9.7 X 106 cells) were injected into predefined regions. Cardiac functions prior to and 3, 6, and 9 months after cell transplantation were assessed by cardiac magnetic resonance imaging. Stem cell transplantation typically improved the heart function stage from New York Heart Association/Canadian Cardiovascular Society class III-IV to I-II. The mean preoperative and postoperative ventricular ejection fractions were 15.8 +/- 5% and 24.8 +/- 5%, respectively. CONCLUSION: CD133+ injection into ischemic myocardium was feasible and safe. Stem cell transplantation alone improved cardiac function in all patients. This technique might hold promise as an alternative to medical management in patients with severe ischemic heart failure who are ineligible for conventional revascularization.

AC133 Antigen↗
PubMed2006

Autologous transplantation of CD133+ BM-derived stem cells as a therapeutic option for dilatative cardiomyopathy.

We report the case of a 58-year-old man with end-stage non-ischemic cardiomyopathy. Baseline transthoracic echocardiography (TTE) and cardiac magnetic resonance (cMRI) revealed a markedly depressed left ventricle systolic function. He underwent autologous CD133+ BM-derived cell transplantation through a minimally invasive approach. During surgery 19 x 10(6) BM-derived stem cells were injected by the transepimyocardial route. Six months after the operation TTE and cMRI showed a clear improvement in left ventricular contractility.

AC133 Antigen↗
PubMed2003

[Sprengel deformity in a nine-year-old boy: diagnosis and therapy].

Sprengel deformity is a congenital malformation with usually unilateral elevation and medial rotation of the scapula. An omovertebral bone is generally present. Associated skeletal malformations are frequently present. Though functional impairment is mild, the cosmetic and psycho-social impairment can be considerable. The prognosis of early surgical therapy is good. The presented case also justifies surgical correction in the older child.

Bone Diseases, Developmental↗
PubMed2002

[Imaging diagnostics of the wrist: MRI and Arthrography/Arthro-CT].

PURPOSE: To evaluate the use of magnetic resonance imaging (MRI) compared with arthrography and arthro-CT (AG/ACT) in patients with wrist pain. METHODS: MRI and arthrography/arthro-CT (AG/ACT) of the wrist joint were retrospectively evaluated in 346 patients over a three-year period. Imaging findings were correlated to surgical results (n = 78) or clinical course in an at least 6-month follow-up. RESULTS: For tears of the triangular fibrocartilage, arthrography, arthro-CT, and MRI demonstrated a sensitivity and specificity of more than 0.96. Only the positive predictive value was superior for arthrography/arthro-CT (0.99 and 0.98, respectively) compared with MRI (0.94). Arthrography was superior for functional diagnosis of scapho-lunate ligament tears (n = 25). Ulno-lunate and ulno-triquetral ligament defects were demonstrated more exactly by arthrography. Traumatic osseous defects, particularly scaphoid fractures (n = 33) and avascular necrosis (n = 17), were better diagnosed using MRI. CONCLUSION: For suspected lesions of the triangular fibrocartilage complex, AG/ACT is slightly more reliable than MRI. However, MRI was found to be highly accurate in diagnosing TFC tears, and is superior to AG/ACT in detecting traumatic and vascular lesions of the wrist.

Arthrography↗
PubMed1999

The moon and madness reconsidered.

Belief that the full moon is associated with psychiatric disturbance persists despite 50 years research showing no association. This article traces the historical roots of belief in the power of the moon to cause disorders the mind, especially insanity and epilepsy. Putative mechanisms of lunar action are critiqued. It is proposed that modern findings showing lack of lunar effect can be reconciled with pre-modern beliefs in the moon's power through a mechanism of sleep deprivation. Prior to the advent of modern lighting the moon was a significant source of nocturnal illumination that affected sleep-wake cycle, tending to cause sleep deprivation around the time of full moon. This partial sleep deprivation would have been sufficient to induce mania/hypomania in susceptible bipolar patients and seizures in patients with seizure disorders. The advent of modern lighting attenuated this lunar effect, especially in modern urban areas, where most 20th century studies of lunar effects on the mind have been conducted. The hypothesis presented in this article is open to empirical validation or falsification. Potential tests for the sleep-deprivation hypothesis of lunar action are discussed.

Humans↗
PubMed1997

Induction of heat shock protein 70 (HSP70) by zinc bis (DL-hydrogen aspartate) reduces ischemic small-bowel tissue damage in rats.

The aim of the study was to determine whether the induction of HSP70 by Zn2+ is able to protect the small bowel of rats against ischemia. Twenty-four male Wistar rats (weight 200-300 g) were divided into four groups: (1) saline treatment for 24 h (n = 4); (2) Zn2+ treatment for 24 h (n = 4); (3) Saline pretreatment for 24 h and ischemia (n = 8); (4) Zn2+ pretreatment for 24 h and ischemia (n = 8). Pretreatment with Zn2+ was carried out by intraperitoneal administration of 50 mg/kg zinc bis (DL-hydrogen aspartate) = 10 mg/kg Zn2+. Ischemia in a defined segment of the small bowel was produced by ligation of the mesenteric vein and artery and ligation of both ends of the segment. Tissue samples were collected before and 2, 4 and 6 h after ligation and investigated by histology, immunohistochemistry and Western blotting. Twenty-four h after i.p. Zn2+ injection, the small bowel expressed increased HSP70 tissue levels. Histology with subsequent grading of ischemic tissue injury showed significantly decreased tissue necrosis after Zn2+ pretreatment and HSP70 induction compared with saline pretreated controls. In conclusion, this study proves that Zn2+ is inducing HSP70 in the small bowel in vivo and hereby able to protect the small bowel against ischemia.

Animals↗
PubMed1997

[Preoperative spiral CT cholangiography with 3-dimensional surface reconstruction: the anatomical imaging potentials, limits and application strategies].

PURPOSE: Evaluation of CT cholangiography compared to i.v. cholangiography concerning its diagnostic value before laparoscopic cholecystectomy and optimisation of CT cholangiography. METHOD: I.v. and CT cholangiographies of 54 patients were retrospectively evaluated by two radiologists. The time interval between contrast infusion and CT was correlated with the assessment of CT cholangiographies to detect the optimal timing for CT scanning. RESULTS: CT cholangiography was judged to be generally better than i.v. cholangiography. The optimal time interval for CT scanning is between 30 min and 60 min post contrast infusion. CONCLUSION: CT cholangiography should replace the conventional tomograms if i.v. cholangiography does not yield sufficient depiction of the biliary tree. It should be performed within 60 min post contrast infusion. Complete abolishment of i.v. cholangiography is not warranted. This is due to the fact that conventional cholangiography can sufficiently delineate the biliary tree and thereby reduce x-ray exposure and cost compared to initial performance of CT cholangiography.

Adult↗
PubMed1997

Clinical significance of three-dimensional helical CT in neurosurgery.

The authors report about a 3-years experience with helical CT and 3-D surface reconstruction applied in neurosurgical patients. All examinations were performed in addition to preexisting diagnostic CT, MRI, or angiography. The aim of this study was to assess the clinical value of this method with regard to planning of the surgical approach to anterior, middle, and posterior skull base and spinal lesions. 75 examinations of 55 patients were analysed and ranked as follows: A = examination with significant additional information for neurosurgical planning of skull base or spinal procedures or for postoperative evaluation of the neurosurgical approach, B = examination with some useful information for the neurosurgical planning or postoperative control, however, without significant advantage as compared to established diagnostic methods, C = examination without significant additional information. Classification was performed independently by two experienced surgeons. Examinations of anterior, middle, and posterior skull base lesions including cerebral aneurysms were in the majority rated as helpful and significantly informative, (A = 21, B = 24, C = 9, n = 54). Three-dimensional imaging of the spine was of clinical value only in specific cases (A = 6, B = 6, C = 9, n = 21). The authors conclude that three-dimensional imaging is a valuable diagnostic tool for pre- and postoperative imaging of tumorous and vascular lesions adjacent to the skull base, allowing for optimal surgical approaches with minimal invasiveness.

Adult↗
PubMed1996

Microsurgical management of ventral and ventrolateral foramen magnum meningiomas.

The authors report their experiences gained from 19 patients with ventral or ventrolateral foramen magnum meningiomas operated on via the dorsolateral, suboccipital transcondylar access route. It is emphasized that the microsurgical management of these lesions includes two important aspects which increase the safety of the procedure: a meticulous preoperative planning based on the microanatomical details of each patient, as well as an individualized tailoring of the surgical approach. There were no deaths, and, in the past 5 years, no neurological complications in this series. Gross total removal of the tumour was achieved in each case. It is concluded that microsurgical removal of ventral or ventrolateral foramen magnum meningiomas with this technique constitutes a safe and recommendable procedure.

Aged↗
PubMed1996

Pattern recognition system for focal liver lesions using "crisp" and "fuzzy" classifiers.

RATIONALE AND OBJECTIVES: To determine the diagnostic performance of an artificial intelligence system for classification of focal liver lesions, in comparison to human observers. METHODS: One hundred forty-three focal hepatic lesions were evaluated with dynamic computed tomography. The study comprised 59 hemangiomas, 24 other benign lesions (focal nodular hyperplasia, adenoma), and 60 malignant liver lesions (18 primary, 42 secondary). All lesions but the hemangiomas were histologically examined by needle biopsy. For delineation of the lesion, a region of interest was defined interactively. The pattern recognition was performed in two steps with initial extraction of textural features: training of a classifier and classification of the lesions. The accuracy of classification of hepatic lesions into three groups (hemangioma, other benign processes, malignant lesions) was tested. The results were compared with those achieved by human observers using receiver operating characteristic statistical analysis. RESULTS: The accuracy (total rate of correct diagnoses) was 90.2%. False classifications were found owing to small size, weak contrast enhancement after bolus injection, respiratory movement, and atypical morphology of the lesion. The area under the receiver operating characteristic curve was not significantly different for computer and human observers. CONCLUSIONS: The system demonstrated a diagnostic accuracy comparable to human observers. Further improvement with increasing numbers of typical computed tomographic series for training of the classifier can be expected.

Adenoma↗
PubMed1995

[The computed tomographic morphology of Crohn's disease and ulcerative colitis].

PURPOSE: To assess the value of computed tomography for the diagnosis of Crohn's disease and ulcerative colitis. METHOD: We analysed the CT examinations of 109 patients with 197 involved bowel locations. 81 patients suffered from Crohn's disease, 28 from ulcerative colitis. Diagnosis was based on the combination of clinical, endoscopic and histopathologic findings. Three radiologists evaluated the CT series concerning the presence of morphologic changes analogous to conventional radiographic findings. RESULTS: In Crohn's disease, we found irregular outer contours in 26% of cases. The bowel wall was thickened in 82%. In acute phases, the bowel wall was thickened in 100%. Abscess and fistula as complications of inflammatory disease were present in 26 and 14% respectively. In ulcerative colitis, a target sign of the bowel wall was present in 40%, whereas in Crohn's disease a homogeneous wall density was present in all but two cases. Reduced attenuation due to submucosal fat deposits was found in 16% and mucosal tunneling in 27% of cases with ulcerative colitis. Even if severe mucosal destructions were found, the outer contour of the gut was smooth and regular in 95% of the ulcerative colitis cases. CONCLUSION: CT can provide additional information on acuity, extent and complications in inflammatory bowel disease. In combination with conventional radiographic findings a three-step classification for Crohn's disease and ulcerative colitis (early changes, acute and chronic phase) can be proposed.

Adolescent↗
PubMed1995

Diagnostic imaging of mesenteric infarction.

PURPOSE: To determine the value of diagnostic imaging in the management of mesenteric infarction. MATERIALS AND METHODS: Within 8 years, 54 patients with mesenteric infarction underwent diagnostic imaging before surgery, including plain radiography (n = 45), ultrasound (US) (n = 29), small bowel follow-through examination (n = 7), colon enema study (n = 7), angiography (n = 16), and computed tomography (CT) (n = 22). Clinical course, laboratory values, and imaging findings were considered in diagnosis. RESULTS: Radiography and US allowed correct diagnoses in five of 18 cases (28%). Only one of 14 fluoroscopic examinations contributed to diagnosis. Fourteen of 16 angiography studies (sensitivity, 87.5%) and 18 of 22 CT examinations (82%) were correct. The difference in sensitivity between CT and angiography was not significant (P > .05). CONCLUSION: CT and angiography are highly sensitive, but CT can also be used to rule out other causes of acute abdomen. Careful evaluation of patient history and clinical situation should lead to suspicion of mesenteric ischemia and early indication for CT.

Aged↗
PubMed1995

Image- and model-based surgical planning in otolaryngology.

Preoperative evaluation of any operating field is essential for the preparation of surgical procedures. The relationship between pathology and adjacent structures, and anatomically dangerous sites need to be analyzed for the determination of intraoperative action. For the simulation of surgery using three-dimensional imaging or individually manufactured plastic patient models, the authors have worked out different procedures. A total of 481 surgical interventions in the maxillofacial region, paranasal sinuses, orbit, and the anterior and middle skull base, in addition to neurotologic procedures were presurgically simulated using three-dimensional imaging and image manipulation. An intraoperative simulation device, part of the Aachen Computer-Assisted Surgery System, had been applied in 407 of these cases. In seven patients, stereolithography was used to create plastic patient models for the preparation of reconstructive surgery and prostheses fabrication. The disadvantages of this process include time and cost; however, the advantages included (1) a better understanding of the anatomic relationships, (2) the feasibility of presurgical simulation of the prevailing procedure, (3) an improved intraoperative localization accuracy, (4) prostheses fabrication in reconstructive procedures with an approach to more accuracy, (5) permanent recordings for future requirements or reconstructions, and (6) improved residency education.

Child↗
PubMed1994

Three-dimensional spiral CT for neurosurgical planning.

We carried out 22 examinations to determine the value of three-dimensional (3D) volumetric CT (spiral CT) for planning neurosurgical procedures. All examinations were carried out on a of the first generation spiral CT. A tube model was used to investigate the influence of different parameter settings. Bolus injection of nonionic contrast medium was used when vessels or strongly enhancing tumours were to be delineated. 3D reconstructions were carried out using the integrated 3D software of the scanner. We found a table feed of 3 mm/s with a slice thickness of 2 mm and an increment of 1 mm to be suitable for most purposes. For larger regions of interest a table feed of 5 mm was the maximum which could be used without blurring of the 3D images. Particular advantages of 3D reconstructed spiral scanning were seen in the planning of approaches to the lower clivus, acquired or congenital bony abnormalities and when the relationship between vessels, tumour and bone was important.

Adult↗
PubMed1994

Ultrasound-guided craniotomy for minimally invasive exposure of cerebral convexity lesions.

The authors describe a method of real-time ultrasound-guided craniotomy for an approach to cerebral convexity lesions. During surgery, a specially designed high frequency (7.5 MHz) sector probe with a thin (11 mm), extended tip is used to image the cerebral lesion through a single burr-hole. The distance between burr-hole and lesion and the direction of the target are then determined from the ultrasound images, and craniotomy is completed with the aid of these parameters. Errors in the preoperative planning of the approach, which might result in incorrect placement of the craniotomy, can easily be recognized and corrected at an early stage of the operation, before the craniotomy has been completed. This technique greatly improves the accuracy in placing craniotomy flaps. Since the risk of misplacing the craniotomy is virtually eliminated in lesions which are identifiable on ultrasound images, the technique allows the surgeon to keep the skull opening as limited as possible.

Brain Neoplasms↗