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Biomedical subjects

K Weigel

Publications and source records attributed to K Weigel.

At least 19 recordsLinked to original sources
PubMed1993

Urological findings in patients with neurosurgically treated tethered spinal cord.

We studied 42 consecutive patients with spina bifida to ascertain the urological relevance of the tethered spinal cord in this condition. We evaluated 35 patients before untethering and 21 with pathological findings after untethering. The main difference after untethering was an increase in bladder capacity in 10 of 17 patients. The general clinical condition improved in 13 patients, was stable in 5 and became worse in 3.

Child↗
PubMed1992

Stereotactic brain biopsy in AIDS.

In the hope of finding a treatable condition, the need for rapid diagnosis in HIV-seropositive patients with brain lesions is apparent. In order to evaluate the efficacy of stereotactic brain biopsy in AIDS patients, we retrospectively studied 25 HIV-infected patients undergoing stereotactic biopsy. Brain lesions were identified with gadolinium-enhanced MRI and/or contrast CT. Brain biopsy was performed using the system of Riechert. From 8 up to 15 small tissue samples from one or two targets were obtained in every patient. The biopsy material was examined cytologically, histologically (including electron microscopy), immunohistochemically and, in part, by animal test and polymerase chain reaction (PCR). A definite diagnosis was achieved in 92%. Diagnosis included primary central nervous system lymphoma (PCNSL) (10), toxoplasmosis (10), progressive multifocal leukoencephalopathy (2) and one case of co-existing toxoplasmosis and cytomegalovirus infection. Two biopsies were non-diagnostic. All PCNSLs showed polymorphic B-cell populations of high malignancy; accurate classification according to the Kiel classification was not possible. In 3 lymphomas Epstein-Barr nuclear antigen (EBNA) 2-mRNA could be detected by PCR and confirmed immunohistochemically by EBNA 2 expression. In 6 cases autopsy confirmed the biopsy diagnosis. Conventional histology was not sufficiently decisive for toxoplasmosis and progressive multifocal leukoencephalopathy, so that immunohistochemistry and animal tests became very important for a final diagnosis. With the help of different morphological and molecular biological techniques stereotactic brain biopsy appears to be an effective method in the diagnosis of HIV-associated brain lesions. In view of the marked radio- and chemosensitivity of PCNSLs it is mandatory to establish an early and accurate histological diagnosis for adequate treatment.

Acquired Immunodeficiency Syndrome↗
PubMed1992

[Primary and secondary tethered cord syndromes. Their nuclear magnetic tomographic diagnosis and comparison with the surgical findings in 40 patients].

The MRT findings in 40 patients with the tethered cord syndrome (TCS) have been compared with the operative findings. In cases of primary TCS (17 patients), MRT showed a low conus medullaris in 15 cases and this was confirmed surgically in 14. Other abnormal findings were lipomas (MRT 12/operatively 13), diastematomyelia (MRT 2/operatively 2) and thickened filum terminale (MRT 6/operatively 3). In secondary TCS (23 patients) postoperatively adhesions were prominent (MRT 16/operatively 23) while low position of the conus was found by MRT in 19 and surgically in 18 patients. Other findings were lipomas (MRT 5/operatively 6), epidermoids (MRT 2/operatively 2) and diastematomyelia (MRT 2/operatively 0). Agreement between MRT and operative findings regarding fixation of the spinal cord is closer in primary TCS (15/17, 88%) than in secondary TCS (16/23, 69%).

Adolescent↗
PubMed1991

Strategy for diagnosis of Toxoplasma gondii in stereotactic brain biopsies.

The colloidal gold method using polyclonal antitoxoplasma antibodies was used to detect Toxoplasma organisms in stereotactic brain biopsies of patients with AIDS. For comparison, conventional histologic staining and additional other immunohistochemical methods were also studied in the same cases. Compared to the other stains, a reliable diagnosis of Toxoplasma gondii could be established with the colloidal gold method in all patients investigated. This method was highly specific and sensitive and stained both the encysted and the tachyzoite forms of the organism. Stronger contrast of the single parasite and better identification is possible if it is applied together with silver enhancement. Conventional staining and immunohistochemical peroxidase techniques are not advantageous, because they allow a diagnosis only by observation of the rare pseudocysts and not by free parasites in tissue, so the colloidal gold method appears to be the preferred method for a rapid diagnosis of cerebral toxoplasmosis, especially in cases where only small amounts of tissue can be obtained.

Acquired Immunodeficiency Syndrome↗
PubMed1991

[Brain biopsies in HIV-infected patients].

Stereotactic brain biopsies of 25 HIV-seropositive patients (age range between 20 and 56 years, 23 males, 2 females) were retrospectively studied. Biopsy material was examined cytologically, histologically, immunohistochemically and electron microscopically. A definitive diagnosis could be established in 23 cases (92%). Diagnosis included non-Hodgkin's lymphoma (10 cases), toxoplasmosis (10 cases), progressive multifocal leukoencephalopathy (PML) (2 cases) and combined toxoplasmosis and lymphoma (1 case). Two biopsies were non-diagnostic. All lymphomas were B-cell lymphomas of high malignancy including one K1-lymphoma. In six cases, in which autopsy was performed, biopsy diagnosis could be confirmed. In one patient suffering from toxoplasmosis, autopsy demonstrated an additional cytomegalovirus infection. Conventional histology was not sufficiently decisive for toxoplasmosis, for some lymphomas and for PML. Stereotactic brain biopsy appears to be an effective method in the diagnosis of HIV-associated brain lesions.

Adult↗
PubMed1991

Experience with the intraoperative frozen section technique for stereotaxic brain tumor biopsies.

The smear preparation technique is usually employed intraoperatively for stereotaxic brain tumor biopsies, whereas the frozen section technique is used in conventional operations, where larger tissue specimens can be obtained. 130 brain tumor biopsies were processed with the frozen section technique and postoperatively submitted to immunohistochemical examination. Subsequent paraffin embedding was not performed. In our study, frozen section diagnosis corresponded in 84% with the immunohistochemistry. Broggi et al. (1984) and Kleihues et al. (1984) demonstrated a similar positive correlation between intraoperative smear preparations and postoperative paraffin embedding. In our investigation, the greatest difficulties arose in cases of suspected lymphoma. Postoperatively, all lymphomas could be immunohistochemically clarified. Due to insufficient material 8% of the cases remained unclarified. Compared to smear preparation, the intraoperative frozen section technique during intervention provided a more accurate assessment of the histology. Furthermore the time needed for the procedure is not much longer than for smear preparation techniques. Reliable antibodies can be used in the remaining frozen material for further differentiation.

Biopsy↗
PubMed1990

A case of dyschondroplasia associated with brain stem glioma: diagnosis by stereotactic biopsy.

We present a 24-year-old patient with multiple chondromas of both hands, the pelvis, the left leg, and an associated brain stem glioma. There was no evidence of hemangioma or dyschromia, and the condition was diagnosed as Ollier's disease, a special type of dyschondroplasia like Maffucci's syndrome and Kast's disease. An increased overall risk for development of malignant skeletal and nonskeletal tumors is associated with Maffucci's syndrome. The risk of malignant degeneration is lower in Ollier's disease. A glioma in the pons and the right lobe of the cerebellum was found in this patient. The literature describes an association with gliomas in only 12 cases of dyschondroplasia and an infratentorial localization in just one case. Signs of malignancy were histologically confirmed in 7 cases without significant preponderance of any one type. Our patient had a low-grade brain stem astrocytoma with fibrillar and gemistocytic components. A stereotactic serial biopsy made it possible to rule out malignant degeneration. Stereotactic brain tumor biopsy as a routine neurosurgical procedure is particularly valuable for deep space-occupying processes and forms the basis for therapy. In the present case, irradiation was not recommended.

Adult↗
PubMed1989

[Initial experiences with implanted drug pumps for continuous intrathecal calcitonin therapy in therapy-resistant pain].

The hormone calcitonin has proved itself for some years in the treatment of chronic pain syndromes. In addition to its known influence on calcium exchange it gives vise to an analgesic effect within the central nervous system and this follows systemic administration or after bolus intrathecal injection. Two patients with chronic non malignant pain are presented in whom continuous delivery pumps have been used for intrathecal Lachs-Calcitonin (Karil, Fa. Sandoz).

Brachial Plexus Neuritis↗
PubMed1989

Hemangioblastomas of the central nervous system. A 10-year study with special reference to von Hippel-Lindau syndrome.

The findings of a 10-year study (1976 to 1986) conducted in southwest Germany on hemangioblastomas (HBL's) of the central nervous system (CNS) are presented. During that period, 47 HBL's were diagnosed and surgically removed in 44 patients, with a good postoperative survival rate and prognosis. The majority (83%) of these tumors were located in the cerebellum. By thorough clinical examination of the patients and careful evaluation of their family background, it was found that 23% of the HBL patients were afflicted with von Hippel-Lindau syndrome. In addition to the CNS tumors, 14 neoplastic or similar lesions were detected in other tissues. These included angiomatosis of the retinae, pheochromocytomas, pancreatic cysts, renal cysts, and renal carcinoma. The diagnosis of von Hippel-Lindau syndrome was thus established in seven families. The authors suggest the need for a screening program for patients with HBL of the CNS which is designed to confirm or exclude ocular or visceral lesions associated with von Hippel-Lindau syndrome.

Adolescent↗
PubMed1987

Somatostatin-like immunoreactivity in cerebroventricular fluid of patients with basal midline tumours.

The concentration of somatostatin-like immunoreactivity (SLI) was determined by specific radioimmunoassay in the cerebroventricular fluid of patients with tumours of the basal midline and compared to findings in patients with multiple sclerosis. Mean SLI levels of the two groups were not significantly different. In patients with basal tumours (astrocytoma, craniopharyngioma, etc.) SLI levels varied widely and tended to increase with increased intracranial pressure. Lateral ventricular SLI levels decreased in patients with blockade of foramen Monro and in patients with communicating hydrocephalus or post-radiation encephalopathy. There was no apparent correlation with dysfunction of the hypothalamohypophyseal axis.

Adolescent↗
PubMed1987

Stereotactic mesencephalotomy versus multiple thalamotomies in the treatment of chronic cancer pain syndromes.

Two neurosurgical centers, Bologna (Italy) and Freiburg (FRG), have compared results obtained with stereotactic mesencephalotomy (SM; Bologna) and multiple thalamotomies (MT; Freiburg) in the surgical treatment of chronic cancer pain syndromes. In total, 161 patients were operated, 109 in Bologna and 52 in Freiburg. In SM the lesions were single and centered on the spinothalamic tract at the mesencephalic level, while in MT the lesions were multiple in the thalamic nuclei (ventrocaudal parvocellular nucleus, nucleus limitans, lamella medialis, centromedian nuclei). The following results emerged after 2-7 months' follow-up: (1) in an antalgic sense, SM was much more beneficial, with 91 patients (83.5%) pain-free after the operation versus 27 patients (51.9%) who had only an attenuation of the pain syndrome after MT; (2) SM, compared to MT, is burdened by mortality and a higher morbidity [2 deaths (1.8%) vs. 0; 3 anesthesia dolorosa and 8 severe gaze palsies (10.1%) vs. only 1 case of permanent aphasia (1.9%)].

Chronic Disease↗
PubMed1987

Sensitivity and specificity of brain stem potentials as a means of differentiating cochlear and retrocochlear disorders (acoustic neuromas).

Between 1980 and 1985 we examined a fairly large group of patients for retrocochlear disorders. Every patient was examined by at least two procedures, registration of brain stem potentials and CT; we had also magnetic resonance images taken of some of these patients. We diagnosed a total of 37 acoustic neuromas in 34 of the patients examined. From our study a conclusion can be drawn about the sensitivity and specificity of brain stem potentials as evidence of an acoustic neuroma. The rate of false negative diagnoses is about 6%. The false positive rate is considerably higher, and it is discussed in detail. The clinical utility of brain stem potentials is illustrated with two case histories. Because of the method's low false negative rate, cochlear disorders diagnosed by registering brain stem potentials need not as a rule be confirmed by modern imaging procedures.

Adult↗
PubMed1986

Computerized tomography-guided stereotactic dentatotomy.

The CT stereotactic technique of dentatotomy is described and illustrated with two examples. With this combined technique, ventriculography or pneumencephalography is no longer needed to determine the target point. In addition, due to the direct representation of anatomic structures in the CT, abnormal positions of the dentate nucleus may be taken into consideration in the determination of the target point and approach for the coagulation probe.

Adult↗
PubMed1985

Ventricular somatostatin-like immunoreactivity in patients with basal ganglia disease.

The concentrations of somatostatin-like immunoreactivity (SLI) in lateral ventricular fluid of patients with extrapyramidal motor disease were determined by specific radio-immunoassay. Mean SLI levels were significantly lower in patients with Parkinson's disease (mean +/- SEM); 42.9 +/- 2.9 fmol/ml) and in patients with dystonic syndromes (39.4 +/- 3.2) than in patients with benign essential tremor (65.3 +/- 9.7). The lowest levels were found in patients with athetosis (34.7 +/- 5.4). In parkinsonian patients somatostatin levels correlated with the degree of akinesia, rigidity and autonomic disturbances.

Adult↗
PubMed1985

Supratentorial space occupying lesions following infratentorial surgery early diagnosis and treatment.

Supratentorial complications of infratentorial surgery are rare. In the last 3 years we have operated on 187 patients with infratentorial lesions and have observed an incidence of 3.7% of supratentorial haemorrhages. Postoperative intracranial air, as shown by early postoperative CT control, was encountered mainly in a subdural frontal location and within the interhemispheric fissure. We performed no surgical decompression of the air accumulation because of the lack of clinical symptoms. Predisposing factors for the development of supratentorial complications remote from the surgical area are hypertonia, female sex, brain atrophy and preoperative shunting procedures. Measures to avoid these complications are discussed.

Adult↗
PubMed1985

X-ray and magnetic resonance stereotaxy for functional and nonfunctional neurosurgery.

By means of new plastic stereotactic ring and head fixers, stereotactic procedures can be combined with MRI, with stereotactic coordinates obtained from the MRI images. The method was rechecked against CT stereotaxy and shows a good correspondence of the target coordinates. With MRI stereotaxy, structures near bony regions will be more accessible than with CT stereotaxy. Moreover, the MRI procedure seems to have advantages for functional therapy without the necessity of contrast ventriculography.

Brain Neoplasms↗