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Biomedical subjects

R Kleinert

Publications and source records attributed to R Kleinert.

At least 19 recordsLinked to original sources
PubMed2006

Lethal brain abscess due to the fungus Scedosporium apiospermum (teleomorph Pseudallescheria boydii) after a near-drowning incident: case report and review of the literature.

A 39-year-old healthy man developed a brain abscess weeks after a near-drowning incident. Scedosporium apiospermum, the anamorph of Pseudallescheria boydii, was isolated from the abscess. The patient died 153 days after the accident despite antifungal therapy. We discuss the role of antifungals and review the literature for comparable cases.

Accidents, Traffic↗
PubMed2001

Vascularized versus non-vascularized nerve transfers: histologic study in rats.

From the clinical point of view, the state of vascularized nerve transfers is clearly demonstrated in the literature. This study was carried out to elicit the basic histologic differences between vascularized and non-vascularized nerve transfers in an animal experiment. In 46 rats, the lateral femoral cutaneous nerve was resected, and an interposition with a free (n=23) ischiatic nerve transfer on one side and a vascularized (n=23) ischiatic nerve transfer on the other side was carried out. Three months postoperatively, the rats were sacrificed and 45 nerve transfers and 46 contralateral reference specimen probes were histologically evaluated. A lower degree of nerve fibrosis and vesicular degeneration of the myelin sheath were found in the vascularized nerve transfers, compared to the free non-vascularized transfers. The thickness of the myelin sheaths was less in the free transfers. From a histologic point of view, a lower degree of degenerative changes was seen in the vascularized nerves after transfer.

Animals↗
PubMed2000

Nonfibrillar diffuse amyloid deposition due to a gamma(42)-secretase site mutation points to an essential role for N-truncated A beta(42) in Alzheimer's disease.

Amyloidogenic processing of the amyloid precursor protein (APP) with deposition in brain of the 42 amino acid long amyloid beta-peptide (A beta(42)) is considered central to Alzheimer's disease (AD) pathology. However, it is generally believed that nonfibrillar pre-amyloid A beta(42) deposits have to mature in the presence of A beta(40) into fibrillar amyloid plaques to cause neurodegeneration. Here, we describe an aggressive form of AD caused by a novel missense mutation in APP (T714I) directly involving gamma-secretase cleavages of APP. The mutation had the most drastic effect on A beta(42)/A beta(40) ratio in vitro of approximately 11-fold, simultaneously increasing A beta(42) and decreasing A beta(40) secretion, as measured by matrix-assisted laser disorption ionization time-of-flight mass spectrometry. This coincided in brain with deposition of abundant and predominant nonfibrillar pre-amyloid plaques composed primarily of N-truncated A beta(42) in complete absence of A beta(40). These data indicate that N-truncated A beta(42) as diffuse nonfibrillar plaques has an essential but undermined role in AD pathology. Importantly, inhibiting secretion of full-length A beta(42 )by therapeutic targeting of APP processing should not result in secretion of an equally toxic N-truncated A beta(42).

Alzheimer Disease↗
PubMed2000

Non-invasive cardiac allograft monitoring: the graz experience.

Based on previous reports by our group, initial studies on non-invasive cardiac graft monitoring have been presented recently. In this study we define new parameters to monitor rejection and infection after heart transplantation (HTX) the ventricular evoked response (VER) T-slew rate parameter is defined as the maximum negative slope in the descending part of the repolarization phase of the VER. We calculated the VER duration parameter in milliseconds and defined it as the time between the pacemaker spike and the cross-over of the baseline, with the slope line used to calculate the VER T-slew rate. During the HTX procedure, we implant wide-band telemetric pacemakers and fractally coated, epimyocardial electrodes (Physios CTM 01 and ELC 54-UP, Biotronik; Berlin, Germany). During each follow-up and on biopsy days, intramyocardial electrogram sequences were obtained and sent via the Internet to the central data-processing unit in Graz. We scored the infection status of the patients before data acquisition. The VER parameters were automatically calculated and send back within a few minutes. We prospectivly compared 1,613 follow-ups from 42 patients with biopsy (International Society of Heart and Lung Transplantation grading) and infection classification. The VER duration parameter did not change during rejection; however, we found an increase during clinically apparent infection. The VER T-slew rate parameter was lower during rejection grade 2 or higher, as well as during clinically apparent infection. The negative predictive value to rule out rejection was 99%. Our results indicate that rejection and infection cause different, reproducible effects on the electrical activity of the transplanted heart. Non-invasive cardiac graft monitoring may reduce the need for surveillance biopsies and may offer a tool to optimize immunosuppressive therapy after HTX.

Action Potentials↗
PubMed2000

Neuronal structure of microvascular transplants with and without neuronal anastomosis.

OBJECTIVE: Latissimus dorsi transplants have little neuronal regenerative capacity without neuronal anastomosis. Histologic differences between transplants with and without neuronal anastomosis and 2 distinct types of neurosurgical reanastomosis are highlighted in this study. PATIENTS AND METHODS: Fifty-four patients with squamous cell carcinomas of the oral cavity (T4) were treated by tumor resection and homolateral neck dissection. The defect was covered with a microvascular latissimus dorsi transplant. In 15 patients, no neuronal anastomoses were performed. In 21 patients, the thoracodorsal nerves were used for microneurosurgical reanastomosis, whereas in 18 patients, the cutaneous branches of the intercostal nerves were used for microneurosurgical reanastomosis. The transplant was examined during surgery and 9 months after surgery by means of a histologic examination of a biopsy specimen. The number of fascicles, the degree of fibrosis, and the myelination were examined. Furthermore, a neurosensory examination was performed 9 months after surgery. RESULTS: Overall, our patients had an average of 12.1 fascicles during surgery. After surgery, patients without neuronal anastomosis showed an average of 4.9 fascicles, patients with nerve anastomosis to the cutaneous branches of the intercostal nerve showed an average of 6.2 fascicles, and patients with anastomosis to the thoracodorsal nerve showed an average of 9.6 fascicles. In cases of nerve anastomosis, a lesser degree of fibrosis was found, together with good myelinization. The clinical examination showed the best neurosensory function in the transplants with anastomosis to the thoracodorsal nerve and the worst function in those without neuronal anastomosis. CONCLUSION: Neuronal reanastomosis led to more surviving neuronal structures in the postoperative histologic specimen. The highest density of fascicles was found in the well vascularized thoracodorsal nerve. The neurosensory function agrees with the histologic result.

Adult↗
PubMed2000

Histologic results of neuronal anastomosis of the microvascular latissimus dorsi transplant.

Latissimus dorsi transplants have little neuronal regenerative capacity without neuronal anastomosis. Histologic differences between transplants with and without neuronal anastomosis and two distinct types of neurotization are highlighted in this study. Eighteen patients after tumor resection and defect coverage with a latissimus dorsi transplant were examined preoperatively and postoperatively by means of a biopsy for histologic examination. The number of fascicles, degree of scarring, myelinization, and fibrosis were examined. All patients had a mean of 11.8 fascicles preoperatively. Patients without neuronal anastomosis showed an average of 5.0 fascicles, patients with nerve anastomosis to the cutaneous branches of the intercostal nerve showed an average of 6.2 fascicles, and patients with anastomosis to the thoracodorsalis nerve showed an average of 9.2 fascicles postoperatively. In cases of nerve anastomosis, a lesser degree of fibrosis was found, together with good myelinization. Neuronal reanastomosis led to more vital neuronal structures in the postoperative histologic specimen. The highest density of fascicles was found in the case of the well-vascularized thoracodorsalis nerve.

Adult↗
PubMed1999

[Indications of cerebral micro-hemorrhage in MRI. Comparative histological findings and possible clinical significance].

Increased use of gradient echo T2*-weighted gradient echo sequences in magnetic resonance imaging (MRI) of patients suffering from primary ICH called attention to foci of signal loss which were suggested to represent remnants of cerebral microbleeds. In a post mortem correlative MR and histopathological study we provide support for this notion. We found areas of signal loss on gradient echo T2*-weighted sequences in 7 out of 11 brains of patients who had died of intracerebral hematoma. Histopathologically, these areas represented hemosiderin deposits indicating previous extravasation of blood. To provide data about the prevalence of these MRI findings in a healthy elderly population a subgroup of participants of the Austrian Stroke Prevention Study was analyzed. We detected foci of signal loss on gradient echo T2*-weighted sequences in 18 out of 280 volunteers (6.4%). MR-based evidence of previous microbleeds may indicate a potentially higher risk of suffering from intracerebral bleeding which could have therapeutic implications for the treatment of acute stroke and for secondary prevention. This hypothesis will have to be tested in future prospective trials.

Aged↗
PubMed1999

Intraspinal primitive neuroectodermal tumour: report of two cases and review of the literature.

Two patients with primary intraspinal primitive neuroectodermal tumour are presented. In a 32-year-old man, the tumour evolved intradurally from a sacral nerve root. Despite repeated surgery and radiochemotherapy, the patient suffered multiple intraspinal tumour relapses and intracranial seedings, and died 29 months after the first diagnosis. In a 17-year-old male adolescent, the tumour was located in the lumbar epidural space, extending into the paraspinal muscles. Following resection and radiochemotherapy, the patient is free from disease 23 months after the initial presentation. The clinical, radiological, histopathological and cytogenetic findings of both patients are presented and the relevant literature is reviewed. Particular attention is given to the histogenetic relationship between peripheral primitive neuroectodermal tumour and Ewing's sarcoma.

Adolescent↗
PubMed1999

Fatal familial insomnia: a new Austrian family.

We present clinical, pathological and molecular features of the first Austrian family with fatal familial insomnia. Detailed clinical data are available in five patients and autopsy in four patients. Age at onset of disease ranged between 20 and 60 years, and disease duration between 8 and 20 months. Severe loss of weight was an early symptom in all five patients. Four patients developed insomnia and/or autonomic dysfunction, and all five patients developed motor abnormalities. Analysis of the prion protein (PrP) gene revealed the codon 178 point mutation and methionine homozygosity at position 129. In all brains, neuropathology showed widespread cortical astrogliosis, widespread brainstem nuclei and tract degeneration, and olivary 'pseudohypertrophy' with vacuolated neurons, in addition to neuropathological features described previously, such as thalamic and olivary degeneration. Western blotting of one brain and immunocytochemistry in four brains revealed quantitative and regional dissociation between PrP(res)(the protease resistant form of PrP) deposition and histopathology. In the cerebellar cortex of one patient, PrP(res) deposits were prominent in the molecular layer and displayed a peculiar patchy and strip-like pattern with perpendicular orientation to the surface. In another patient, a single vacuolated neuron in the inferior olivary nuclei contained prominent intravacuolar granular PrP(res) deposits, resembling changes of brainstem neurons in bovine spongiform encephalopathy.

Adult↗
PubMed1999

Histopathologic analysis of foci of signal loss on gradient-echo T2*-weighted MR images in patients with spontaneous intracerebral hemorrhage: evidence of microangiopathy-related microbleeds.

BACKGROUND AND PURPOSE: Patients with spontaneous intracerebral hemorrhage (ICH) frequently have small areas of signal loss on gradient-echo T2*-weighted MR images, which have been suggested to represent remnants of previous microbleeds. Our aim was to provide histopathologic support for this assumption and to clarify whether the presence and location of microbleeds were associated with microangiopathy. METHODS: We performed MR imaging and correlative histopathologic examination in 11 formalin-fixed brains of patients who had died of an ICH (age range, 45-90 years). RESULTS: Focal areas of signal loss on MR images were noted in seven brains. They were seen in a corticosubcortical location in six brains, in the basal ganglia/thalami in five, and infratentorially in three specimens. Histopathologic examination showed focal hemosiderin deposition in 21 of 34 areas of MR signal loss. No other corresponding abnormalities were found; however, hemosiderin deposits were noted without MR signal changes in two brains. All specimens with MR foci of signal loss showed moderate to severe fibrohyalinosis, and there was additional evidence of amyloid angiopathy in two of those brains. CONCLUSION: Small areas of signal loss on gradient echo T2*-weighted images indicate previous extravasation of blood and are related to bleeding-prone microangiopathy of different origins.

Aged↗
PubMed1999

Combined restorative proctocolectomy and pancreaticoduodenectomy for familial adenomatous polyposis.

This is a case report on FAP in a 41-year-old woman in which preoperative examination showed a giant tubulovillous adenoma of the descending duodenum surrounding the papilla of Vater, in addition to pancolon adenomatous polyposis, and isolated adenomas in the gastric antrum and corpus. As it was impossible to remove the giant villous adenoma in the duodenum endoscopically, prophylactic surgical treatment was chosen consisting of restorative proctocolectomy and additional pancreaticoduodenectomy. Flat tubulovillous adenomas in the gastric corpus were successfully removed by total snare biopsies before operation. FAP coli patients treated by prophylactic surgery are now known to be at risk of developing adenomas anywhere in the intestine and many affected patients later die from upper gastrointestinal tumors. In this single case report, the simultaneous occurrence of FAP coli and giant villous adenoma of the duodenum indicates the frequent outcome of this genetic alteration requiring lifelong surveillance. This rare case report includes a short survey of the relevant literature.

Adenomatous Polyposis Coli↗