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Biomedical subjects

M Weber

Publications and source records attributed to M Weber.

At least 163 records · Page 9Linked to original sources
PubMed2001

Pseudo-achalasia following laparoscopically placed adjustable gastric banding.

BACKGROUND: The complication of pseudo-achalasia may occur after laparoscopic adjustable gastric banding (LAGB) in patients with normal band position and normal stomal width. We hypothesized that this complication occurs especially in patients with preexisting insufficiency of the lower esophageal sphincter (LES), who show poor compliance secondary to lacking the sensation of satiety and who therefore also have insufficient weight loss at follow-up. METHODS: Early and late postoperative barium meal studies of 120 LAGB patients were retrospectively analyzed to identify patients who developed esophageal widening and dysmotility despite normal band position and normal stomal width. Results were compared with preoperative endoscopies, clinical findings, each patient's compliance with dietary instructions and postoperative weight loss. RESULTS: 9/120 patients developed pouch dilatation, esophageal widening and esophageal dysmotility as a late complication, despite normal band position and normal stomal width. All these patients had shown preexisting insufficiency of their LES endoscopically. They all showed bad compliance with dietary instruction, and they all abused their distal esophagus as an additional pouch. 7 of these patients presented with insufficient weight loss at follow-up, whereas of 3 other patients with pre-existing LES insufficiency who had shown good compliance, only 1 showed insufficient weight loss. Insufficient weight loss after 1 year was significantly more common in patients with pre-existing LES insufficiency (8/12 patients, 67%) than in patients with a competent LES (26/108 patients, 24%). CONCLUSION: Patients with pre-existing LES insufficiency appear to be at risk for pouch dilatation and esophageal decompensation despite normal band position and normal stomal width. These patients are prone to show lack of satiety and poor compliance with dietary instruction, use of their lower esophagus as additional space for food, and tend to have insufficient weight loss. Preoperative manometry should be used to identify such patients, where the indication for gastric banding should be discussed very critically.

Adult↗
PubMed2001

The effects of laparoscopic adjustable gastric banding on the proximal pouch and the esophagus.

BACKGROUND: Pouch development is a potentially serious problem following gastric banding, and reoperation is often demanded to maintain long-term function of the lap band. Laparoscopic gastric banding was performed with two different calibrations of the pouch. Within a period of 12 months, postoperative pouch behavior with regard to volume and shape was evaluated retrospectively, as were changes in the distal esophagus. METHODS: The pouches of 14 patients with intraperitoneal band positioning were calibrated at 25 ml. The volumes of 54 patients operated by a suprabursal technique were set at 15 ml. We performed three radiological examinations and calculated the volumes using the ellipsoid formula d1 x d2 x d3 x pi/6. Four morphologically different pouch types have been observed: regular, concentric, eccentric-medial and eccentric-lateral. The phi-angle corresponds to the angle between the spinal column and the gastric band. RESULTS: In the first group, the pouch volume increased from 21.2 ml +/- 21.2 to 87.9 ml +/- 64.6 (p=0.006) and the BMI fell from 47.1 kg/m2 +/- 8.4 to 38.1 kg/m2 +/- 7.0 (p=0.001). The pouch volume of the second group increased from 10.4 ml +/- 5.8 to 38.8 ml +/- 29.1 (p<0.001), and the BMI reduced from 48.4 kg/m2 +/- 6.9 to 39.3 kg/m2 +/- 6.7 (p<0.001). If the phi-angle is smaller than 4 degrees, the pouch is of the eccentric-medial type. CONCLUSIONS: The transbursal operative technique is responsible for the development of the eccentric-medial pouch. If the anterior sero-muscular fixative sutures tear, an eccentric-lateral pouch results. All pouch types are affected by changes at the pouch-esophageal junction and by pathological developments in the distal and middle oesophagus.

Analysis of Variance↗
PubMed2001

Congenital pseudarthrosis of the tibia in pediatric patients: MR imaging.

OBJECTIVE: The purpose of this study was to describe the characteristics of congenital pseudarthrosis of the tibia on MR images of infants and children and to assess the value of MR imaging in evaluating this disease. CONCLUSION: MR imaging of congenital pseudarthrosis allows assessment of the type and extension of the disease. It is especially recommended for the evaluation of periosteal and soft-tissue changes near the pseudarthrosis.

Child, Preschool↗
PubMed2001

Glucose induces beta-cell apoptosis via upregulation of the Fas receptor in human islets.

In autoimmune type 1 diabetes, Fas-to-Fas-ligand (FasL) interaction may represent one of the essential pro-apoptotic pathways leading to a loss of pancreatic beta-cells. In the advanced stages of type 2 diabetes, a decline in beta-cell mass is also observed, but its mechanism is not known. Human islets normally express FasL but not the Fas receptor. We observed upregulation of Fas in beta-cells of type 2 diabetic patients relative to nondiabetic control subjects. In vitro exposure of islets from nondiabetic organ donors to high glucose levels induced Fas expression, caspase-8 and -3 activation, and beta-cell apoptosis. The effect of glucose was blocked by an antagonistic anti-Fas antibody, indicating that glucose-induced apoptosis is due to interaction between the constitutively expressed FasL and the upregulated Fas. These results support a new role for glucose in regulating Fas expression in human beta-cells. Upregulation of the Fas receptor by elevated glucose levels may contribute to beta-cell destruction by the constitutively expressed FasL independent of an autoimmune reaction, thus providing a link between type 1 and type 2 diabetes.

Adolescent↗
PubMed2001

Angiotensin II receptor blockers and cardiovascular outcomes: the evidence now and in the future.

The blood-pressure-lowering efficacy of both angiotensin-converting enzyme inhibitors (ACE-I) and angiotensin II receptor blockers (ARBs) has been clearly demonstrated in recent years, although there is evidence that within the ARB class the individual therapies not necessarily identical in terms of sustained and consistent antihypertensive efficacy over the entire closing period. However, the results of the recent HOPE study have demonstrated that ACE-I have a wider role to play in treating cardiovascular disease, and support the idea that ACE inhibition specifically has a vascular protective effect. the most dramatic benefits were seen in patients with systolic blood pressures in the hypertensive range. The ability of the ACE-I to provide protective effects beyond blood pressure control may be due to their ability to attenuate the breakdown of kinins as well as a role in reducing angiotensin II. These data post the question as to whether the pharmacological properties of the ARBs, in addition to their antihypertensive efficacy, may also play a significant role in influencing cardiovascular outcomes. A number of prospective long-term studies, including VALUE, SCOPE, LIFE, VALIANT, OPTIMAAL, VAL-HEFT and CHARM I-III, are investigating the effects of the ARBs or mortality and morbidity in patients with cardiovascular disease. These studies should answer important questions with respect to the role that ARBs may have in influencing cardiovascular outcomes, although it remains to be seen whether ARBs can match the protective effects of ramipril in high-risk patients. Given the excellent tolerability of the ARBs, it will be of value to examine the influence of ARBs on cardiovascular outcomes in all relevant patient groups.

Angiotensin Receptor Antagonists↗
PubMed2001

[Restoration of blood circulation in reperfusion of ischemic tissues].

In experiment there were studied changes of the tissue blood circulation and microcirculation during postischemic reperfusion of skeletal muscles with various density of capillaries. It was established that reactive hyperemia, caused mainly by enhancement of extracapillary tissue blood flow. While persistence of durable arterial hypertension the capillaries quantity and potential volume of microcirculatory bed are reducing, negatively influencing the blood circulation restoration process during postischemic reperfusion. In chronic ischemia the potential volume of microcirculation is increasing, securing complete restoration of blood circulation in postischemic reperfusion.

Animals↗
PubMed2001

[Eales].

Eales' disease, first described by Eales Henry in 1880, is an idiopathic obliterative vasculopathy that primarily affects the peripheral retina of adults. From nosologic point of view, we could distinguish the "true Eales disease" affecting males in India and portions of the Middle East and the "Eales' like disease" with no geographical or sex predisposition. Vascular sheathing, peripheral retinal nonperfusion and neovascularization are the principal clinical and angiographic findings. It remains a diagnostic by exclusion and retinal diseases with other causes of inflammation or neovascularization must be excluded. In the absence of a specific treatment, retinal photocoagulation to the nonperfused retina and vitrectomy for recurrent vitreal hemorrhage could be proposed.

Humans↗
PubMed2000

H19 gene expression is up-regulated exclusively by stabilization of the RNA during muscle cell differentiation.

H19 is a paternally imprinted gene whose expression produces a 2.4 kb RNA in most tissues during development and in mammalian myoblastic cell lines upon differentiation. Deletion of the active maternal allele of H19 and its flanking regions in the mouse leads to biallelic methylation and loss of imprinting of the neighbouring Igf2 gene. The function of H19 RNA remains unknown and, although polysome-associated, the absence of a conserved open reading frame suggests that it does not encode a protein product. We describe a novel post-transcriptional regulation of H19 gene expression which, in spite of this lack of coding capacity, is dependent on translational activity. We show that stabilization of the RNA is solely responsible for its accumulation during in vitro muscle cell differentiation. This conclusion is based on the finding that inhibition of protein synthesis results in a dramatic destabilization of H19 RNA in proliferating mouse C2C12 myoblastic cells but not in differentiated cells, and on run-on experiments which showed that the rate of transcription of H19 RNA remains constant during muscle cell differentiation. This mechanism could also be involved in H19 gene expression during mouse development in addition to its transcriptional activation which we have shown to occur.

Animals↗
PubMed2000

Temporal dispersion of cortically evoked single motor unit potentials in ALS.

Peristimulus time histograms (PSTHs) can be used to investigate corticomotoneuronal dysfunction in amyotrophic lateral sclerosis (ALS). The most characteristic change is temporal dispersion of the primary peak. We recorded PSTHs in the extensor digitorum communis with voluntary motor units activation (standard PSTHs) or at rest (non-activated PSTHs). Standard PSTHs were recorded in 29 motor units of 12 healthy control subjects and 12 sporadic ALS patients. Double primary peaks were seen in three motor units of two healthy control subjects and 10 motor units from five ALS patients. The number of subpeaks was up to three in most of the normal motor units as well as in the earlier component of double primary peaks. The subpeaks were smaller and less discernible in the later component of double primary peaks. Non-activated PSTHs of ALS patients demonstrated similar decomposition of subpeaks in the motor units with significantly increased variability of latency. Similar findings in the standard PSTHs and non-activated PSTHs suggest that the abnormalities seen in ALS are independent of the membrane potential of the spinal motoneuron and therefore supraspinal in origin. The decomposed additional later component may indicate activation of slow conducting corticospinal tracts.

Amyotrophic Lateral Sclerosis↗
PubMed2000

The split hand in ALS has a cortical basis.

Loss of highly fractionated movement involving the thumb and index finger is an early characteristic of hand dysfunction in many ALS patients. These movements are largely subserved by the 'thenar complex' including the first dorsal interosseus muscle (FDI), whereas the 'hypothenar complex', innervated by the same myotome, has less ability to fractionate and is relatively spared. This suggests that in ALS, hand dysfunction and wasting is related to corticomotoneuronal representation and input. To determine whether corticomotoneuronal input to the thenar spinal pool is preferentially impaired compared to the hypothenar spinal pool in ALS, we studied 18 ALS patients and 11 normal subjects. Compound muscle action potentials (CMAPs) and motor evoked potentials (MEPs) of the thenar and hypothenar complexes were evoked by peripheral nerve stimulation and transcranial magnetic stimulation. In healthy control subjects the cortical/peripheral (MEP/CMAP) ratios were significantly larger for the thenar complex suggesting a stronger corticomotoneuronal input to this muscle complex (P<0.005). This was not the case in ALS patients. Comparing the ratios between control subjects and patients revealed a significant reduction for the thenar complex (P<0.02) in ALS patients but not for the hypothenar complex. We conclude that corticomotoneuronal input to the thenar complex is preferentially affected in ALS and that corticomotoneuronal disease may be the prime determinant of hand dysfunction and wasting.

Amyotrophic Lateral Sclerosis↗
PubMed2000

Increased skin lactate in complex regional pain syndrome: evidence for tissue hypoxia?

To investigate oxygen metabolism in complex regional pain syndrome (CRPS), the authors measured skin lactate via dermal microdialysis performed on patients with CRPS (n = 11) and healthy control subjects (n = 11). In addition, they measured blood lactate. Although venous lactate was unaltered, skin lactate was increased in patients with CRPS (2.95 mmol/L; control subjects 1.74 mmol/L; p < 0.005). These results suggest enhanced anaerobic glycolysis, probably as a result of chronic tissue hypoxia.

Adult↗
PubMed2000

[Waldenstrom disease revealed by a peripheral motor neuron disease].

BACKGROUND: An association between motor neuron disease and Waldenström disease is rarely reported in the literature. The association with peripheral neuropathy and IgM monoclonal gammapathy is well known. CASE REPORT: In our patient, the malignant monoclonal gammapathy had an unusual antigen pattern. This patient was MAG (myelin-associated glycoprotein) negative but showed a very positive serology for GM1 ganglioside and SGPG (3-sulfated glycuronly paragloboside). DISCUSSION: This is the fifth such case to be reported associated a malignant dyglobulinemia with an MAG-negative IgM gammapathy. It is the first case with positive serology for both the GM1 ganglioside and SGPG.

Aged↗
PubMed2000

Eosinophils maintain their capacity to signal and release eosinophil cationic protein upon repetitive stimulation with the same agonist.

Eosinophils contain in their granules eosinophil cationic protein (ECP) and other basic proteins that have been implicated in immunity to parasites and pathophysiology of chronic allergic responses. In a model of eosinophil degranulation, we show that eosinophils release ECP upon short-term GM-CSF priming and stimulation with either platelet-activating factor (PAF) or the anaphylatoxin C5a, but not eotaxin. Restimulation with the same agonist (PAF or C5a) was unsuccessful as assessed by monitoring intracellular calcium concentration and ECP release. In contrast, upon an intermediate washing step, eosinophils rapidly transduced PAF and C5a signals followed by significant ECP releases. Ligand-binding studies demonstrated that only a proportion of PAF receptors is internalized upon cell stimulation and that washing of the cells removes the agonist from the cell surface. Upon repetitive stimulation, eosinophils with less than 50% of the original ECP content were obtained. Such eosinophils did not increase cellular ECP levels even in the presence of the eosinophil survival factor GM-CSF in overnight cultures. In vivo studies revealed that eosinophils always express detectable amounts of ECP under chronic inflammatory conditions. In conclusion, we have shown that eosinophils maintain their capacity to degranulate upon repetitive stimulation with the same agonist as long as the receptor is not occupied from a previous stimulation. The cellular content of ECP appears to be a no limiting factor in the case of repetitive stimulation, implying that mature eosinophils may not require a significant ECP resynthesis.

Blood Proteins↗
PubMed2000

Clonal chromosome abnormalities in enchondromas and chondrosarcomas.

We report cytogenetic findings in short-term cell cultures from five enchondromas and four chondrosarcomas. Clonal chromosome aberrations were found in one case of enchondroma, and in all cases of chondrosarcoma. The only enchondroma with nonrandom abnormalities had a reciprocal t(8;17)(q23;p13), and monosomies 9, 19, and/or 22. In contrast to the few karyotypic findings in one of five enchondromas, the four chondrosarcomas were commonly characterized by cytogenetic heterogeneity, with a tendency for increasing karyotypic complexity in higher grade tumors. Two cases, one grade III and one metastasizing grade II chondrosarcoma, revealed hypodiploid stem- and sidelines with loss of chromosomes 6, 10, 13, 14, and 22, as common chromosomal abnormalities, suggesting a distinct karyotypic pattern in a subset of biologically aggressive chondrosarcomas.

Adolescent↗