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Biomedical subjects

M Roth

Publications and source records attributed to M Roth.

At least 91 records · Page 5Linked to original sources
PubMed1998

Revision endoscopic sinus surgery: the Thomas Jefferson University experience.

Since its introduction, functional endoscopic sinus surgery (FESS) has demonstrated success rates of 76% to 98%. A small group of the patients in whom initial FESS and optimal medical therapy fail require revision endoscopic sinus surgery (RESS). This group has recently been studied by several authors, and we have evaluated a group of 90 RESS patients selected from 753 consecutive primary FESS patients. Patients were followed for a mean of 22.8 months. Extent of disease, history of polyps, allergy, previous traditional endonasal sinus surgery, male gender, chronic steroid use, and the presence of a deviated septum all appeared to adversely affect RESS outcome. The surgeon's knowledge of the sinus anatomy is critical, especially in revision sinus cases in which landmarks are distorted or absent. In our review, RESS was associated with a 1% major complication rate and was successful in 67% of patients. Computer-assisted endoscopic sinus surgery integrates preoperative imaging with realtime endoscopic visualization, augments the surgeon's knowledge of anatomy, and helps to minimize patient risk.

Adult↗
PubMed1998

[Depersonalization experiences in adolescents].

OBJECTIVES: The present study examined how widespread experiences of depersonalization are in adolescence and how they are connected to self-esteem and self-awareness. METHODS: We tested 352 adolescents aged 12 to 16 years by means of standardized questionnaires. RESULTS: The results show: (1) that the majority of adolescents has had few experiences of depersonalization. (2) We observed clear sex differences in the course of age. Among female adolescents the number of experiences of depersonalization increased with age, whereas among male adolescents the number began to decrease in mid-adolescence. (3) Adolescents whose experiences of depersonalization are intense do not differ from their counterparts in the study with regard to self-esteem; however, their sense of self-awareness is heightened. The results are discussed in respect to the formation of identity in adolescence.

Adolescent↗
PubMed1997

Effects of amlodipine on gene expression and extracellular matrix formation in human vascular smooth muscle cells and fibroblasts: implications for vascular protection.

Vascular smooth muscle cells (VSMC) are involved in the pathogenesis of hypertension and coronary artery disease. Amlodipine, a calcium channel blocker of the dihydropyridine type, is widely used in the therapy of these diseases, and has been shown to reduce the progression of the underlying pathophysiological mechanisms, such as atherosclerosis and restenosis. Research on the impact of calcium channel blockers on cell behavior has revealed an antiproliferative effect on VSMC. Cell proliferation is tightly controlled by permanent interaction of cells with their surrounding microenvironment, the extracellular matrix (ECM). The ECM is subjected to a continuous turnover and implicated in (i) stabilization and compartmentalization of tissue architecture and (ii) local binding and preservation of growth factors and cytokines. These growth factors and cytokines can be released during degradation of the ECM, and can function as local inflammatory factors without de novo synthesis. In this context, we assessed the effects of amlodipine on the composition of the ECM and related factors. We investigated the effects of amlodipine on (i) the regulation of cellular cholesterol metabolism, (ii) the activation of genes encoding for inflammatory factors, (iii) gene expression and turnover of ECM compounds, and (iv) the activity of matrix-degrading enzymes. Most of these effects of calcium channel blockers require direct induction of gene expression. In this respect, we demonstrate that amlodipine increases expression of the cytokine interleukin-6 by directly activating the respective gene promoter in human VSMC.

Amlodipine↗
PubMed1997

Neutron crystallographic evidence of lipase-colipase complex activation by a micelle.

The concept of lipase interfacial activation stems from the finding that the catalytic activity of most lipases depends on the aggregation state of their substrates. It is thought that activation involves the unmasking and structuring of the enzyme's active site through conformational changes requiring the presence of oil-in-water droplets. Here, we present the neutron structure of the activated lipase-colipase-micelle complex as determined using the D2O/H2O contrast variation low resolution diffraction method. In the ternary complex, the disk-shaped micelle interacts extensively with the concave face of colipase and the distal tip of the C-terminal domain of lipase. Since the micelle- and substrate-binding sites concern different regions of the protein complex, we conclude that lipase activation is not interfacial but occurs in the aqueous phase and is mediated by colipase and a micelle.

Animals↗
PubMed1997

Effects of octreotide treatment on restenosis after coronary angioplasty: results of the VERAS study. VErringerung der Restenoserate nach Angioplastie durch ein Somatostatin-analogon.

BACKGROUND: The VERAS study (VErringerung der Restenoserate nach Angioplastie durch ein Somatostatin-analogon [Prevention of Restenosis Following Angioplasty With a Somatostatin Analogue]) was a placebo-controlled trial to evaluate the effects of octreotide for the prevention of restenosis after coronary angioplasty. Octreotide is a somatostatin analogue with antiproliferative properties on smooth muscle cell growth in vitro that limits myointimal thickening of arteries in balloon injury models. METHODS AND RESULTS: Patients received either octreotide or placebo, starting 1 hour before angioplasty and continued for 3 weeks. The minimal luminal diameters before and after angioplasty and at 6-month follow-up were analyzed with a digital quantitative algorithm. Of the initial 274 patients recruited, 217 (108 in the octreotide group and 109 in the placebo group) could be analyzed after a complete 6-month evaluation: the minimal luminal diameters were 1.67+/-0.57 mm in the octreotide-treated group and 1.66+/-0.64 mm in the placebo group (two-paired P=.70), and the relative losses were 0.16+/-0.22 and 0.13+/-0.21 (two-paired P=.27). The restenosis rates were also identical in both treatment groups: final diameter stenosis > or =50% (34.3% versus 33.9%, two-paired P=1.0), loss of > or =50% of the initial gain (34.3% versus 33.9%, two-paired P=1.0), and absolute reduction of minimal luminal diameter >0.72 mm (29.6% versus 24.8%, two-paired P=.45). Likewise, there was no difference with regard to the incidence of clinical events (death, myocardial infarction, bypass operations, reintervention). Octreotide was well tolerated, with the exception of gastrointestinal side effects, which were three times more common than in the placebo group. CONCLUSIONS: Octreotide did not reduce the angiographically determined restenosis rate or the incidence of major clinical events after coronary angioplasty.

Adult↗
PubMed1997

[Steroid-induced myopathy in left-sided ulcerative colitis. Successful treatment and continued therapy with the topical steroid budesonide].

BACKGROUND: Glucocorticoids are an effective treatment of ulcerative colitis. The occurrence of steroid side effects depends on dosage and duration of steroid treatment. It may be a high as 80%. A rare side effect of glucocorticoid therapy is steroid induced myopathia. There exists an acute and a chronic form of steroid induced myopathia. Chronic steroid myopathia affects mainly the proximal musculature of the lower and upper extremities and leads to proximal muscle weakness. Histologically, an atrophy of type IIb-muscle fibers can be found. Chronic steroid myopathia occurs after prolonged treatment with higher doses of glucocorticoids. CASE REPORT: The case report describes a 25 year old male patient with left-sided ulcerative colitis who developed chronic steroid myopathia after several months of glucocorticoid treatment. After switching from systemic steroids to budesonide the symptoms of myopathia disappeared. Left-sided ulcerative colitis remained in remission. CONCLUSION: The case documents the disappearance of a severe steroid side effect after switching from a systemic steroid to budesonide.

Administration, Topical↗
PubMed1997

[Robot-assisted knee endoprosthesis].

With the development of powerful computer systems, computer-assisted medical diagnosis and therapy have become common over the last 10 years. Even in the surgical field, computer- and robotic-assisted techniques are becoming practical but are not yet used on a daily basis. In the orthopaedic field, computer and robotic assistance is used in planning and performing demanding three-dimensional osteotomies, setting pedicle screws in the spine and milling the femoral medullary canal in total hip replacement. This article introduces a computer- and robotic-assisted system for performing arthroplasty in total knee replacement procedures.

Computer Simulation↗
PubMed1997

Mutations in the MHC class I-like candidate gene for hemochromatosis in French patients.

A candidate gene for hemochromatosis has recently been localized on the short arm of chromosome 6, about 4 megabases telomeric to the major histocompatibility complex. It encodes a protein that exhibits significant similarity to the HLA class I molecules and can be provisionally designated HLA-hc. Genotype analysis of 94 hemochromatosis patients living in France and a similar number of controls confirms that the disease is strongly associated with homozygosity at nucleotide 845 (72% of the patients and none of the controls carry two copies of the 845A variant). The data are consistent with hemochromatosis being a heterogeneous disease: about 79% of the cases in this sample would be caused by a defect in HLA-hc and 21% by an unrelated mechanism. A second variant (187 G) enriched on patient chromosomes that do not carry the 845A mutation might influence the affinity of a ligand for HLA-hc; the exact nature of this ligand remains to be discovered. The 845A variant is the best genetic marker for the disease identified to date, and the detection of 845A homozygosity should now permit diagnosis of a readily curable disease and the prevention of sometimes deadly complications in at least 72% of the patients.

Genes, MHC Class I↗
PubMed1997

Absence of the hemochromatosis gene Cys282Tyr mutation in three ethnic groups from Algeria (Mzab), Ethiopia, and Senegal.

A Celtic origin for hemochromatosis, a common genetic iron metabolism disorder, has been postulated for a long time. To check whether the two mutations recently identified in the HLA-class I candidate gene for this disease were found only in Caucasians, we examined their frequencies in individuals originating from Algeria, Ethiopia, and Senegal. The presumably disease-causing mutation, responsible for the Cys282Tyr substitution, was not found in any member of these ethnic groups, although it was shown to be highly prevalent in populations of European ancestry. This geographic distribution supports the previously suggested Celtic origin for the disease. In contrast, the mutation responsible for the His63Asp substitution is not restricted to European populations. Although absent in the Senegalese, it was found on about 9% of the chromosomes of the Central Ethiopians and Algerians (Mzab) genotyped for this study. This second mutation, which probably represents a common variant unrelated to hemochromatosis, thus appears to have occurred earlier than that responsible for the Cys282Tyr substitution. More detailed population studies are needed to provide information on the age of these two mutations and eventually show how the hemochromatosis-causing mutation chronologically spread throughout Europe.

Algeria↗
PubMed1997

Video-assisted resection of hypertrophied and fibrous intraventricular tissue.

There is increasing interest in endoscopic techniques in cardiac surgery. However, use of the endoscope during open heart operations is still not routine. Cardioscopy has been used in patients with hypertrophied obstructive cardiomyopathy, asymmetric septal hypertrophy, or membranous subaortic stenosis. We demonstrate the resection of this pathologic tissue under direct visualization. With this technique we could increase the safety and accuracy of this surgical procedure. Beside this advantage, the entire operating room staff could follow the surgical intervention, which increases its educational side-effect.

Cardiomyopathy, Hypertrophic↗
PubMed1997

Reoperations after dacron patch aortoplasty with heparinized femoro-femoral bypass.

Dacron patch aortoplasty used to be a standard therapy in some surgical units. Occurrence of aneurysm formation after this procedure is well known. The incidence of aneurysms is reported to be 0-35% with a high risk of lethal rupture. We report three cases of aneurysm repair of the descending thoracic aorta after dacron patch aortoplasty using femoro-femoral extracorporeal system. Heparin-coated system was used primarily to prevent ischemic spinal cord injury through hypotension of the distal aorta and secondarily to reduce the risk of intraoperative hemorrhage.

Adult↗
PubMed1997

Effects of 1- and 6-month spaceflight on bone mass and biochemistry in two humans.

The bone mineral density and the biochemical parameters exploring bone cell activities were analyzed in two cosmonauts who spent 1 and 6 months, respectively, in the Russian MIR station. Measurements were performed before the flight, after the flight, and after a recovery period. At the end of the first month, peripheral QCT measurements indicated a slight decrease of trabecular bone mass in the distal tibial metaphysis. However, after 6 months of spaceflight, a more marked loss of trabecular and cortical bones was observed in the tibia, and was still significant after 6 month recovery in the trabecular compartment, whereas a decrease was no longer observed in the cortical envelope. No change was observed in either compartment of the distal radius at any time. Ultrasound BUA of the calcaneus was greatly reduced by the first month, followed by a more dramatic decrease after month 6. Ultrasound SOS detected no change. Parameters reflecting bone formation activity appeared to be depressed after both missions. In contrast, no dramatic change in resorption parameters was observed, except for a trend toward an increase in pyridinoline. In conclusion, the lower weight-bearing bones appeared more sensitive than the upper ones in terms of spaceflight-induced bone loss. This probably explained the absence of marked systemic biochemical data changes. This study further suggests that recovery in the tibial trabecular compartment 6 months after landing was not completed after a 6 month mission.

Adult↗
PubMed1997

A successful, preventive-oriented village health worker program in Hebron, the West Bank, 1985-1996.

Village health rooms (VHRs) were established in villages with no on-site health facilities in the Hebron District of the West Bank, beginning in 1985. By 1991, the program served a total population of 40,000 in 49 VHRs and by the end of 1996 covered 69 villages in Hebron and 20 in other districts that were previously served by visiting vaccination teams and nearby clinics. The VHRs provide close contact with the population of mothers for well child and pregnancy care, health education and provide visiting doctor/nurse teams for backup services and supervision. Data on coverage, utilization, costs, and outcome measures are presented. The program is accepted and grows despite adverse social and political conditions.

Community Health Services↗