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Biomedical subjects

G Huber

Publications and source records attributed to G Huber.

At least 55 records · Page 3Linked to original sources
PubMed1998

Alteration of cerebral blood flow in patients with bacterial and viral meningoencephalitis.

PURPOSE: Our purpose was to investigate cerebral blood flow disturbances in patients with bacterial and viral meningoencephalitis. METHODS: Forty-two patients with acute bacterial and viral meningoencephalitis and 14 control subjects were studied using 99mTc-hexamethylpropyleneamine oxime (HMPAO) single-photon emission computed tomography (SPECT). SPECT images were evaluated semiquantitatively. The results were compared with clinical severity of the meningoencephalitis assessed at the time of the SPECT study with the Hunt and Hess scale, with separately recorded focal clinical signs, and with the Glasgow outcome scale (GOS) after 3 weeks. RESULTS: Count density values were significantly reduced in patients with bacterial meningoencephalitis as compared with the control subjects. Inhomogeneous tracer accumulation assessed by asymmetry indexes was significantly greater in patients than in the control group. With increasing Hunt and Hess scores, the count density values decreased and the asymmetry indexes increased. Patients with a poor outcome (GOS 1 to 3) had significantly higher asymmetry indexes and lower CDV values than did patients with a good outcome. CONCLUSION: Global and focal alterations of cerebral perfusion are frequent in bacterial and viral meningoencephalitis and correlate with acute clinical state.

Adult↗
PubMed1997

The heterogeneous course of schizophrenia.

Findings on the course and outcome of schizophrenia, the limitations of Kraepelin's opinion, and data supporting a continuum hypothesis of endogenous psychoses are presented. The European long-term investigations, the Zürich, Lausanne and Bonn studies are consistent with the view that diagnoses must be made independently of outcome; nearly a quarter show full psychopathological and 56% a social remission. Several factors are relevant to the long-term course and outcome. In the Bonn Study, 43% of subjects showed long-term remission, with only a mild deficit state ('pure defect') consisting of dynamic and cognitive basic symptoms, and 35% revealed characteristic schizophrenic residues. Eighty-seven per cent were living at home permanently at the most recent follow-up; 56% were socially recovered, i.e., fully employed, yet only 38.6% were at their previous occupational level. Twelve course types could be differentiated and were ranked according to social remission rate. The results led to a revision of classical descriptions of an incessant progression of schizophrenia. The outcome is largely independent of the duration of illness; there is no increasing deterioration in the later decades of the disease, often showing a trend toward improvement (the 'second, positive bend'), even 20-40 years after onset. According to Zubin, the results of the European long-term studies and the Vermont Study have revolutionized our knowledge about schizophrenia and emancipated it from the yoke of inevitable chronicity. The findings of the Bonn Study, the first systematic study of prodromes, and of the prospective basic symptom-oriented study on the early diagnosis of schizophrenia led, in parallel with the gradual development of the basic symptom concept, to a new view of the evolution of schizophrenia.

Disease Progression↗
PubMed1997

Identification and characterization of wheat grain albumin/globulin allergens.

Bakers' asthma, an immediate-type allergic response to the inhalation of cereal flours, is an important occupational disease among workers of the baking and milling industries, and the salt-soluble proteins of wheat and rye flour dust are considered the most relevant allergens. In order to identify and characterize the major IgE-binding proteins, the polypeptide composition of the albumin/globulin protein fraction obtained from different cultivars was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and high-resolution two-dimensional polyacrylamide gel electrophoresis with immobilized pH gradients in the first dimension (IPG-Dalt), followed by immunoblotting with sera from asthmatic bakers. Relevant allergens were isolated by micropreparative IPG-Dalt and blotting onto polyvinylidenedifluoride membranes and identified by amino acid composition analysis or N-terminal amino acid sequence analysis. SDS-PAGE, IPG-Dalt, and immunoblotting demonstrated that the sera of the bakers allergic to flour contained IgE antibodies which bound to numerous albumin/globulin polypeptides in the 70, 55, 35, 26-28, and 14-18 kDa areas. More detailed investigations using IPG-Dalt revealed cultivar-specific differences in IgE-binding. It was also demonstrated that the majority of the allergens were not single polypeptide spots, but consisted of up to ten isoforms of similar molecular mass but different isoelectric points. Amino acid composition analysis and N-terminal amino acid sequence analysis, which were performed for nine allergens located in the 14-18, 26-28, and 35 kDa areas, revealed homologies to amylase/protease inhibitors, acyl-CoA oxidase and fructose-bisphosphate-aldolase from wheat, barley, maize, and rice, respectively.

Albumins↗
PubMed1997

[Are self-perceivable neuropsychological deficits in patients with neuroses or personality disorder diagnoses indicative of later schizophrenia?].

For the first time, the present study assessed the achievable predictive value of early self-experienced neuropsychological deficits for the fater development of schizophrenia. Ninety-six patients with DSM-III-R diagnoses mainly of the formerly neurotic or personality disordered field, of whom 81% had shown such basic disorders at the time of the index examination and therefore were classified as persons at high risk of developing schizophrenia, were re-examined for schizophrenia. After an average follow-up period of about 8 years, more than half of the re-examined sample had developed a schizophrenic disorder according to DSM-III-R. The outcome of schizophrenia versus no schizophrenia was predicted correctly in 77% of cases by the presence or absence of self-experienced disturbances of perception, thought, speech or action.

Adolescent↗
PubMed1997

Expression and characterization of human beta-secretase candidates metalloendopeptidase MP78 and cathepsin D in beta APP-overexpressing cells.

Human beta-secretase candidates, MP78 (h-MP78, EC 3.4.24.15) and cathepsin D (Cat D, EC 3.4.23.5), were evaluated for their ability to enhance amyloid-beta-protein (A beta) secretion when overexpressed in beta APP-containing cells. HEK-293 cells stably co-expressing h-MP78 or Cat D and h-beta APP695 were metabolically labeled with [35S]methionine and A beta secretion was quantified in the conditioned media by immunoprecipitation and ELISA without showing any significant increase in A beta production. Because Cat D is known to have a higher affinity for APP-substrate containing the Swedish familial Alzheimer's disease double mutation (SFAD, K595N and M596L substitutions in beta APP695) than for the wild type substrate [Dreyer et al., Eur. J. Biochem., 224 (1994) 265-271], the effect of Cat D overexpression was tested in a HEK293/beta APPSFAD stable cell line. ELISA analysis of the conditioned media from these cells did also not reveal any increase in A beta generation. In addition, recombinant h-MP78 purified from E. coli cleaved an APP-derived substrate spanning the beta-secretase site (ISEVKMD1AEFRHDS) at multiple sites, but the beta-site cleavage was only a minor one; cleavage occurred predominantly at K-M and E-F bonds. Human liver Cat D also cleaved the same substrate at multiple sites, yet the major cleavage at pH 4.0 occurred at the amyloidogenic D1 site. These findings indicate that h-MP78 does not have the cleavage specificity required for a beta-secretase protease and although Cat D fulfilled the amyloidogenic cleavage specificity, the results of the co-expression experiments make both enzymes less likely candidates as relevant beta-secretases.

Amino Acid Sequence↗
PubMed1997

Synaptic beta-amyloid precursor proteins increase with learning capacity in rats.

The precursor proteins of Alzheimer's disease beta-amyloid peptide, the beta-amyloid precursor protein isoforms, comprise a family of neuronal proteins with synaptic localization whose physiological roles in brain are poorly understood. One possible role for synaptic proteins is involvement in neuronal plasticity. After exposure to an enriched environment compared to impoverished conditions, rats exhibited superior cognitive capacity. Up to approximately four-fold increased overall levels of beta-amyloid precursor proteins were found in cortical/subcortical tissue of the enriched animals displaying significantly more synapses immunoreactive for the different beta-amyloid precursor protein isoforms (beta-amyloid precursor protein695- and beta-amyloid precursor protein751/770) in hippocampus and adjacent occipital cortex. This correlation thus provides in vivo evidence for an association of beta-amyloid precursor proteins with plastic changes induced by complex environment with consequences for cognitive functions and suggests that impaired beta-amyloid precursor protein metabolism at synapses might contribute to brain dysfunction in Alzheimer's disease.

Amyloid beta-Protein Precursor↗
PubMed1997

Medialization of the patella in total knee arthroplasty.

Patellar complications of total knee arthroplasty remain the most common cause of pain and reoperation. Laboratory studies have suggested that medialization of the patella will improve tracking of the patella on the trochlea of the femoral component. The purpose of this study was to determine if clinical medialization of the patellar component on the patellar bone would improve tracking of the patella as demonstrated radiographically. Sixty-two knees were randomized so that 31 knees had a centrally placed patellar component and 31 had the patellar component placed on the medial two thirds of the patellar bone. There was no difference between the two groups with respect to either clinical or radiographic results in the first year after surgery. There was no improvement compared with previous reports in the incidence of tilt and displacement. The one improvement was a reduction in the incidence of lateral release. Thus, consequences of lateral release such as postoperative morbidity, avascular necrosis of the patella, and stress fracture of the patella can be avoided. It is recommended that the patellar component be placed on the medial two thirds of the patella to reduce the occurrence of lateral release. Tracking of the patella during surgery can be assessed using a single suture placed at the superior pole of the patella, and this technique in combination with the no-thumbs test provides an additional means of evaluation for patellar tracking.

Adult↗
PubMed1997

[Computed tomographic and magnetic resonance tomographic findings in pilocytic astrocytoma].

PURPOSE: In a retrospective study we examined the predilection sites, the CT and MR morphology and the contrast behaviour of intracranial pilocytic astrocytoma (PA) in a large number of patients. MATERIAL AND METHODS: The study consists of 47 patients (18 male, 29 female, mean age 10.1 years) with histologically proven PA. RESULTS: The chief predilection site turned out to be the hypothalamic region (15/47 = 32%). The other regions involved were (in descending order): brain hemispheres 8/47 = 17%; cerebellar vermis 7/47 = 15%, cerebellar hemispheres; thalamic nuclei and pontomedullar region 4/47 = 8.5% each; pineal gland 2/47 = 4%; pons, lamina tecti and optic fascicle 1/47 = 2% each. The PA presented 24/47 = 51% cysts; 7/47 = 15% calcifications; 2/47 = 4% necrosis and 1/47 = 2% perifocal oedema. In three cases (3/47 = 6%) CT and MRI showed no contrast enhancement. CONCLUSION: PA appear in almost all brain regions but there is a clear preference of the hypothalamic region. PA of the hypothalamic region are a special subgroup. They are often associated with neurofibromatosis 1, tend to infiltrate surrounding structures, and to disseminate into the intracranial and spinal subarachnoid space.

Adolescent↗
PubMed1997

Early self-experienced neuropsychological deficits and subsequent schizophrenic diseases: an 8-year average follow-up prospective study.

The aim of the present study was to investigate the potential predictive value of early self-experienced neuropsychological deficits for the subsequent development of schizophrenia. A total of 96 patients with DSM-III-R diagnoses of personality disorders (formerly called 'neurotic disorders') who had been examined for the presence of such subjective experiences of deficits with standardized instruments were re-examined for the possible development of schizophrenic symptoms. After an average follow-up period of about 8 years, more than 50% of the patients had developed schizophrenia according to DSM-III-R criteria. In 77% of cases the outcome 'schizophrenia vs. no schizophrenia' was correctly predicted by the earlier presence or absence of self-experienced disturbances of thought, speech, memory, perception and action. These findings suggest that certain self-experienced neuropsychological deficits are able to indicate susceptibility to psychosis.

Adolescent↗
PubMed1996

Generation of mice with a 200-kb amyloid precursor protein gene deletion by Cre recombinase-mediated site-specific recombination in embryonic stem cells.

Gene disruptions and deletions of up to 20kb have been generated by homologous recombination with appropriate targeting vectors in murine embryonic stem (ES) cells. Because we could not obtain a deletion of about 200 kb in the mouse amyloid precursor protein gene by the classical technique, we employed strategies involving the insertion of loxP sites upstream and downstream of the region to be deleted by homologous recombination and elicited excision of the loxP-flanked region by introduction of a Cre expression vector into the ES cells. In the first approach, the loxP sequences were inserted in two successive steps and after each step, ES cell clones were isolated and characterized. Deletion of the loxP-flanked sequence was accomplished by introducing the cre gene in a third step. In the second approach, ES cells containing the upstream loxP cassette were electroporated simultaneously with the downstream loxP targeting vector and the Cre expression plasmid. ES cells were obtained that gave rise to chimeric mice capable of germ-line transmission of the deleted amyloid precursor protein allele.

Amino Acid Sequence↗
PubMed1996

beta-APP cognitive function versus beta-amyloid--induced cell death.

The beta-amyloid precursor protein (beta-APP) has been hypothesized to play an important role in the establishment of synaptic connections. Icv injections of anti-beta APP antibodies into rat brains produced no appreciable effect on subsequent learning of a passive avoidance task whereas memory assessed 1 day later in a retention test was impaired in anti-beta-APP--but not control-IgG-injected animals. This suggests a possible involvement of beta-APPs in cognitive functions. In order to evaluate the properties of the proteolytic A beta-fragment accumulating in Alzheimer's disease brains, four different neuronal cell types were exposed to A beta 1-42 for 24 hours. All cells degenerated in response to A beta, yet chromosomal condensation and internucleosomal DNA fragmentation, typical for apoptosis, occurred in only three of the cell types tested. These findings suggest that beta-APPs may play an important role in cognitive processes and additionally, that their alternative proteolytic product A beta may be differentially toxic to neuronal cell types, inducing cell death either by necrosis or by apoptosis.

Amyloid beta-Peptides↗
PubMed1996

Regional association of developmental venous anomalies with angiographically occult vascular malformations.

This study reviews the neuroradiological findings of 43 patients with a developmental venous anomaly in order to discuss the clinical significance of this entity. All patients underwent unenhanced and contrast-enhanced computer tomography and magnetic resonance tomography, as well as selective angiography, and were followed for at least 2 years. In 40% (17 of 43) of patients a cryptic vascular malformation was found in the proximity to the developmental venous anomaly. Neurological symptoms were present in 8 of 17 patients (47%) in this group. Patients with an isolated developmental venous anomaly had symptoms in 19% (5 of 26), but none of them had experienced a hemorrhage. Magnetic resonance was the most sensitive method for the diagnosis of both types of lesions and alterations of the adjacent parenchyma. These results further support that developmental venous anomalies represent a clinically benign entity. However, patients with an association of a developmental venous anomaly and a cryptic vascular malformation are at risk for hemorrhage from their angiographically occult vascular malformation. Magnetic resonance proved to be the imaging modality of choice for both entities and is appropriate for diagnosis and follow-up.

Adolescent↗
PubMed1996

[Incidence of postmyelography syndrome and postmyelography complaints after lumbar puncture with the Sprotte pencil-like needle in comparison with the Quincke needle].

PURPOSE: Myelography in combination with a postmyelography CT is an important presurgical examination because of its excellent visualisation of the disc, the bone and the contrast-filled dura. Side effects after myelography can be observed in up to 50% of patients. The pathophysiological mechanism is thought to be increased cerebrospinal fluid leakage at the puncture site. Since the introduction by Sprotte in 1979 of the pencil-point needle, a modification of Whitacre's needle, fewer complaints after lumbar puncture have been reported. The aim of the study was to examine the influence of two types of needle points and the temperature (37 degrees C vs 21 degrees C) of the contrast medium (CM; iotrolan, Isovist) on the incidence of side effects of lumbar puncture for myelography. MATERIAL AND METHODS: In a prospective randomized trial the incidence of complaints after lumbar puncture with intrathecal CM application was evaluated by the use of a 21-G pencil-point needle as modified by Sprotte compared to our usual 22-G needle with a Quincke bevel. Some 412 patients (201 female, 211 male; mean age 54.05 +/- 7.4 years) were investigated. Directly after examination and 1. 3 and 5 days later the patients were questioned about complaints (headache, neck stiffness nausea, vomiting, buzzing in the ear and dizziness). The results were tested by the chi square test. RESULTS: A significantly lower incidence of complaints was seen after lumbar puncture with the pencil-point needle/Quincke needle (headache: 6.3%/18.9%, P < 0.0001; headache lasting 3 days: 0.5%/7.8%, P < 0.0001; headache lasting 5 days: 0%/2.4%, P = 0.0305; nausea: 0%/4.9%, P = 0.0009; vomiting: 0%/3.4%, P = 0.0009; dizziness: 0%/3.4%, P = 0.0074; neck stiffness: 0%/3.4%, P = 0.0074). The temperature of the CM had no influence on the complaints. No influence was seen on the quality of the myelogram. No relation to sex and age was found. CONCLUSION: Complaints after lumbar puncture and myelography are caused by the cerebrospinal fluid leakage at the puncture site. The incidence of side effects related to this leakage can be reduced by using a pencil-point needle. The temperature of the CM has no influence on the complaints.

Adolescent↗
PubMed1996

[Biomechanics of the shoulder and therapeutic applications].

The influence of biomechanics in surgery of the locomotor apparatus has been constantly increasing over the last few decades. The purpose of this study was to determine wether biomechanical studies can significantly influence therapy and treatment of shoulder injuries, especially shoulder instability. The investigation was performed on 23 fresh human specimens with intact capsular ligaments of the glenohumeral joint. A Bankart lesion from 3 o'clock to 6 o'clock was repaired, and a Bankart repair and anterior inferior capsular shift, as described by Neer, were performed. The measurement was done on six clinically relevant positions of instability: superior, anterior, anterior-inferior, inferior, posterior-inferior, posterior. Measurement was done using a specially developed strain-gauge system. It was demonstrated that both instability and too much stability of the shoulder joint lead to a significant change in shoulder biomechanics. The anatomical O-position of the glenohumeral joint in 110 degrees of abduction is a position of about 60 degrees of external rotation compared to the O-position for clinical measurement. From the therapy point of view, one has to ask for anatomical reconstruction instead of tight repair in soft-tissue repair in the glenohumeral joint. Immediate post-operative rehabilitation in a 60 degrees range of motion is possible.

Adult↗
PubMed1995

Cloning and functional expression of a metalloendopeptidase from human brain with the ability to cleave a beta-APP substrate peptide.

Using a combination of PCR and hybridization screening, we have isolated a cDNA clone for a metalloendopeptidase (h-MP78) from a human temporal cortex library. This 2.5-kb cDNA encodes a 689-amino acid protein with a predicted molecular mass of approximately 78.5 kDa. The primary structure of h-MP78 exhibits high similarity to those of porcine (94%) and rat (92%) thimet oligopeptidase. Expression of the cDNA in HEK-293 resulted in the production of an active enzyme able to cleave a chromogenic beta-APP derived substrate peptide KTEEISEVKM-P-nitro-anilide. RNA blot analysis of various human tissues revealed one major species of h-MP78 mRNA of approximately 2.55 kb. The highest level of mRNA was found in the brain.

Amino Acid Sequence↗
PubMed1995

Circadian rhythm of vital signs, norepinephrine, epinephrine, thyroid hormones, and cortisol in schizophrenia.

Changes in the circadian rhythmicity in vital signs, catecholamines, thyroid hormones, and cortisol have been observed in psychiatric disorders, most notably in depression. With respect to schizophrenia, the literature is scanty. We report here on the circadian parameter estimates of the vital signs, epinephrine, norepinephrine, triiodothyronine, thyroxine, thyroid stimulating hormone, and cortisol in the blood of 34 healthy subjects, 89 drug-free schizophrenic patients, and 25 neuroleptic-treated schizophrenic patients. The analyses are based on the cosine model to fit the experimental data. The circadian profiles of heart rate, blood pressure, and oral temperature are similar among schizophrenic patients and healthy subjects. Neuroleptic-treated patients have significantly higher MESORs (the daily mean) of serum norepinephrine and epinephrine than healthy subjects. The TSH MESOR is significantly lower in schizophrenic patients; the MESOR of triiodothyronine also shows a tendency to be nonsignificantly lower in schizophrenic patients compared with control subjects. The circadian serum thyroxine and cortisol profiles are similar in the three groups. The data show that the circadian profiles of vital signs in drug-free chronic schizophrenic patients who are not chronically hospitalized are similar to those of healthy subjects and that the increase in serum catecholamines and the apparent lowering in some thyroid indices might induce a down-regulation in the noradrenergic receptor system that could contribute to the pathophysiology of schizophrenia.

Adolescent↗