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Biomedical subjects

G Schmid

Publications and source records attributed to G Schmid.

At least 37 records · Page 2Linked to original sources
PubMed2002

Vertebral body infarction indicating midthoracic spinal stroke.

STUDY DESIGN: Case report. OBJECTIVE: To illustrate the significance of vertebral body infarction as the only confirmatory sign of spinal cord ischemic stroke. SETTING: Department of Neurology, St. Josef-Hospital, Bochum, Germany. CASE DESCRIPTION: A 65-year-old man presented with clinical features suggesting spontaneous spinal cord infarction in the territory of the left sulcocommissural artery at the level of Th 8. Sequential magnetic resonance imaging (MRI) investigations failed to demonstrate infarction of the spinal cord but T2-weighted images revealed bone marrow hyperintensities of vertebra Th 9 and 10 in their left and dorsal parts consistent with vertebral body infarction. CONCLUSION: In clinically presumed spontaneous spinal cord infarction and unremarkable signaling of the spinal cord during sequential MRI investigations vertebral body infarction may serve as the only confirmatory sign of spinal cord ischemic stroke.

Aged↗
PubMed2002

Anthrax in Europe: its epidemiology, clinical characteristics, and role in bioterrorism.

In the 2001 bioterrorist attack in the United States, in which at least 22 cases of anthrax occurred, there was initial uncertainty as to whether the index case was acquired from natural sources, and many of the additional cases posed diagnostic challenges to clinicians unfamiliar with the disease. The existence in Europe of terrorist groups with demonstrated violent tendencies suggests Europe is not immune to bioterrorist attack, and the same epidemiological and clinical confusion could happen here. Bacillus anthracis is distributed widely in the soils of Europe and foci of animal disease occur, notably in southern and eastern Europe. Sporadic human cases occur in these areas, and occasional additional cases have been acquired from contaminated, imported materials or acquired in countries outside of Europe, where anthrax may be common. Depending upon the intent of a bioterrorist, illness-caused B. anthracis could take one of several clinical forms-inhalational, cutaneous or gastrointestinal-and each would pose diagnostic difficulties. Understanding the epidemiologic, pathophysiologic and bioterrorism principles of anthrax are the clinician's best means of early detection of cases.

Animals↗
PubMed2002

[Lumbar intraspinal juxtafacet cysts: MR imaging and CT-arthrography].

PURPOSE: To present data on the MR imaging appearance of lumbar intraspinal juxtafacet cysts (JFC) and to assess the importance of additional CT arthrography. MATERIAL AND METHODS: Twenty-eight patients (16 women, 12 men) with a mean age of 64 years (range: 43 - 82), who underwent MR imaging because of radicular pain or spinal claudication, were found to have an intraspinal cyst associated with the facet joint. In 14 patients, additional CT-arthrography was performed to determine whether a communication exists between the cyst and the facet joint and to try to rupture the cyst. RESULTS: In T(2)-weighted images, juxtafacet cysts show a typical pattern consisting of a hyperintense center and hypointense rim. The center is likely to be inhomogeneous because of recurrent hemorrhage in the cyst. In T1-weighted images, the cysts are hypo/isointense. Irregular hyperintensity may indicate subacute hemorrhage, which may aggravate the clinical symptoms. MR allows superior visualization of the cyst in all anatomical planes. It also enables assessment of typical accompanying changes, such as degenerative spondylolisthesis and facet hypertrophy. All patients, who had CT-arthrography, were found to have a direct communication between joint space and cyst. Transarticular rupture of the cyst was possible in five patients. Two of these five patients had good to excellent improvement, and the remaining three patients underwent surgery. CONCLUSION: MR imaging is the method of choice for diagnosing lumbar intraspinal juxtafacet cysts. CT-arthrography of the facet joint is helpful in cases with difficult differential diagnosis, and in the preoperative planning. Furthermore, it assists in the primary interventional treatment.

Adult↗
PubMed2001

Electromagnetic compatibility of electronic implants--review of the literature.

The aim of the article was to provide an overview of published studies regarding the electromagnetic compatibility (EMC) of electronic implants. The available literature was sorted according to combinations of implant types and sources of interference. Several experiments concerning the susceptibility of pacemakers to mobile phones have been performed. The results of these experiments suggest measures that may be used to prevent the disturbance of pacemakers. For instance, instead of carrying the activated mobile phone in the breast pocket it is recommended that a distance of 30 cm be maintained between the pacemaker and the mobile phone, and that the mobile phone be used on the contralateral side of the pacemaker's location. Similar measures may be recommended for patients with implantable cardioverter defibrillators when using mobile phones. Patients with electronic implants should walk rapidly through anti theft-devices because some of these devices are liable to disturb implants. Patients with cardiac pacemakers should not be subjected to magnetic resonance imaging as far as possible. For a variety of combinations of implants and interference sources, e.g. cardiac pacemakers and base station antennas, no studies were found in the literature. It is strongly recommended that trials be carried out to evaluate the potential risk for patients in these settings.

Cochlear Implants↗
PubMed2001

Chemically induced metal-to-insulator transition in Au55 clusters: effect of stabilizing ligands on the electronic properties of nanoparticles.

The cluster compound Au55(PPh3)12Cl6 has been reanalyzed by photoelectron spectroscopy giving direct evidence for a nonmetallic behavior of the individual Au clusters as long as their ligand shell remains intact. The exposure to x-rays during the measurements is found to partly decompose the shell by removal of the chlorine atoms, resulting in a metallic behavior of the clusters as demonstrated by a steplike intensity at the Fermi energy. These observations resolve a long-standing controversy about the metallic behavior of ligated Au clusters emphasizing, in addition, the influence of the local environment on the electronic properties of nanoscaled materials.

Journal Article↗
PubMed2001

Acute hemodynamic effects of inhaled nitric oxide, dobutamine and a combination of the two in patients with mild to moderate secondary pulmonary hypertension.

INTRODUCTION: The use of low-dose dobutamine to maintain hemodynamic stability in pulmonary hypertension may have a detrimental effect on gas exchange. The aim of this study was to investigate whether inhaled nitric oxide (INO), dobutamine and a combination of the two have beneficial effects in patients with end-stage airway lung disease and pulmonary hypertension. METHOD: Hemodynamic evaluation was assessed 10 min after the administration of each drug and of their combination, in 28 candidates for lung transplantation. RESULTS: Administration of INO caused a reduction in mean pulmonary arterial pressure (MPAP), an increase in PaO2 with a significant reduction in venous admixture effect (Qs/Qt).Dobutamine administration caused an increase in cardiac index and MPAP, with a decrease in PaO2 as a result of a higher Qs/Qt. Administration of a combination of the two drugs caused an increase in the cardiac index without MPAP modification and an increase in PaO2 and Qs/Qt. CONCLUSION: Dobutamine and INO have complementary effects on pulmonary circulation. Their association may be beneficial in the treatment of patients with mild to moderate pulmonary hypertension.

Administration, Inhalation↗
PubMed2001

Metabolic-flux analysis of continuously cultured hybridoma cells using (13)CO(2) mass spectrometry in combination with (13)C-lactate nuclear magnetic resonance spectroscopy and metabolite balancing.

Protein production of mammalian-cell culture is limited due to accumulation of waste products such as lactate, CO(2), and ammonia. In this study, the intracellular fluxes of hybridoma cells are measured to determine the amount by which various metabolic pathways contribute to the secretion of waste products derived from glucose. Continuously cultured hybridoma cells are grown in medium containing either 1-(13)C-, 2-(13)C-, or 6-(13)C-glucose. The uptake and production rates of amino acids, glucose, ammonia, O(2), and CO(2) as well as the cellular composition are measured. In addition, the (13)C distribution of the lactate produced and alanine produced by the hybridomas is determined by (1)H-NMR spectroscopy, and the (13)CO(2)/(12)CO(2) ratio is measured by on-line mass spectrometry. These data are used to calculate the intracellular fluxes of the glycolysis, the pentose phosphate pathway, the TCA cycle, and fluxes involved in amino acid metabolism. It is shown that: (i) approximately 20% of the glucose consumed is channeled through the pentose shunt; (ii) the glycolysis pathway contributes the most to lactate production, and most of the CO(2) is produced by the TCA cycle; (iii) the pyruvate-carboxylase flux is negligibly small; and (iv) the malic-enzyme flux is estimated to be 10% of the glucose uptake rate. Based on these flux data suggestions are made to engineer a more efficient glucose metabolism in mammalian cells.

Algorithms↗
PubMed2001

Solid- and solution-phase synthesis of highly-substituted-pyrrolidine libraries.

Starting from a complex bicyclic beta-lactam scaffold we have demonstrated the possible production of libraries of a new class of drug-like, highly substituted pyrrolidines. The choice of the type of substitution was made by optimizing various synthetic routes. The selection of each compound is the result of a filtration of a large virtual combinatorial chemical space, using simple criteria. The access to these complex pyrrolidines needed only four to six synthetic steps.

Chemistry, Organic↗
PubMed2001

X-ray structure of junctional adhesion molecule: structural basis for homophilic adhesion via a novel dimerization motif.

Junctional adhesion molecules (JAMs) are a family of immunoglobulin-like single-span transmembrane molecules that are expressed in endothelial cells, epithelial cells, leukocytes and myocardia. JAM has been suggested to contribute to the adhesive function of tight junctions and to regulate leukocyte trans migration. We describe the crystal structure of the recombinant extracellular part of mouse JAM (rsJAM) at 2.5 A resolution. rsJAM consists of two immunoglobulin-like domains that are connected by a conformationally restrained short linker. Two rsJAM molecules form a U-shaped dimer with highly complementary interactions between the N-terminal domains. Two salt bridges are formed in a complementary manner by a novel dimerization motif, R(V,I,L)E, which is essential for the formation of rsJAM dimers in solution and common to the known members of the JAM family. Based on the crystal packing and studies with mutant rsJAM, we propose a model for homophilic adhesion of JAM. In this model, U-shaped JAM dimers are oriented in cis on the cell surface and form a two-dimensional network by trans-interactions of their N-terminal domains with JAM dimers from an opposite cell surface.

Animals↗
PubMed2001

Strategies for partner notification for sexually transmitted diseases.

BACKGROUND: Partner notification has been practiced for decades, with substantial resources directed towards it, and with little evidence on whether it has made a public health impact on disease transmission. Most of the evaluations were not randomized controlled trials, and were conducted in the United States, prior to the HIV/AIDS epidemic. There are reasons to question whether partner notification for gonorrhoea and chlamydia is applicable to HIV. It is also questionable whether interventions for the developed world are applicable to the developing world. OBJECTIVES: This review aims to compare the effects of various sexually transmitted disease (STD) partner notification strategies, including to compare provider referral with contract and patient referral, and to compare different patient referral strategies to each other. In addition to updating previous reviews, it addresses partner notification in developing countries as well as in developed countries, with particular consideration for HIV/AIDS. It attempts to address some of the methodological limitations of earlier reviews. SEARCH STRATEGY: The search strategy included MEDLINE, EMBASE, Psychological Abstracts, Sociological Abstracts, the Cochrane Controlled Trials register, the proceedings of the International AIDS Conferences and the International Society for STD Research meetings. SELECTION CRITERIA: The review includes published or unpublished randomised controlled trials (RCTs) comparing two or more partner notification strategies for people diagnosed with STDs. DATA COLLECTION AND ANALYSIS: For each comparison within each study, the difference in the rate of partners elicited, notified, medically evaluated, harmed, etc, the 95% confidence interval, and if significant, the numbers needed to treat (NNT) were calculated. MAIN RESULTS: We found 11 RCTs, including 8014 participants. Only two trials were conducted in developing countries, and only two trials were conducted among HIV positive patients. There was some risk of bias in all the included trials. The review found moderately strong evidence that: 1. provider referral alone, or the choice between patient and provider referral, when compared with patient referral among patients with HIV or any STD, increases the rate of partners presenting for medical evaluation; 2. contract referral, when compared with patient referral among patients with gonorrhoea, results in more partners presenting for medical evaluation; 3. verbal, nurse-given health education together with patient-centred counselling by lay workers, when compared with standard care among patients with any STD, results in small increases in the rate of partners treated. REVIEWER'S CONCLUSIONS: There is a need for evaluations of interventions combining provider training and patient education, and for evaluations conducted in developing countries. All partner notification evaluations, but especially those among HIV positive patients, need to measure potential harmful effects, such as domestic violence, to ensure that partner notification does more good than harm.

Chlamydia Infections↗
PubMed2001

Activation of alpha 6 GABAA receptors on depolarized cerebellar parallel fibers elicits glutamate release through anion channels.

Rat cerebellar synaptosomes labeled with [3H]D-aspartate ([3H]D-ASP) were exposed in superfusion to muscimol. The GABA(A) receptor agonist did not affect [3H]D-ASP basal release or the overflow provoked by 15mM K(+); muscimol potentiated the 35mM K(+)-evoked overflow of [3H]D-ASP or endogenous glutamate. Membrane potential measured by Rhodamine 6G fluorescence was -65mV under resting conditions and -32mV in the presence of 35mM K(+). The membrane potential was not significantly affected by muscimol. The muscimol effect on the K(+)(35mM)-evoked [3H]D-ASP overflow was not inhibited by omitting external Ca(2+) or by entrapping BAPTA to chelate cytosolic Ca(2+). Muscimol lost its ability to release glutamate following superfusion with D-aspartate to deplete cytosolic glutamate by heteroexchange suggesting that GABA(A) receptor activation elicits release of cytosolic glutamate. The non-transportable glutamate carrier blockers dihydrokainate or DL-TBOA did not reduce the muscimol potentiation. This was abolished by the anion channel blockers niflumic acid and NPPB. To conclude, when cerebellar parallel fiber terminals are sufficiently depolarized, activation of alpha6 GABA(A) receptors on these terminals mediates glutamate release in addition to that evoked by depolarization. This extra-release does not occur by exocytosis or transporter reversal but involves the opening of anion channels present on parallel fiber terminals.

Animals↗
PubMed2001

Hepatitis B vaccination in sexually transmitted disease (STD) clinics: a survey of STD programs.

BACKGROUND: Hepatitis B virus infection causes substantial morbidity and mortality in the United States. Sexual activity is the most commonly reported risk factor among persons with acute hepatitis B, yet hepatitis B vaccine coverage among adolescents and adults with high-risk sexual practices is low. Sexually transmitted disease (STD) clinics are potentially efficient settings for vaccine administration to persons with high-risk sexual practices; however, little is known about hepatitis B vaccination activities in these settings. GOAL: To gain information about policies and activities for vaccinating against hepatitis B in STD clinic settings. STUDY DESIGN: In April 1997, a questionnaire was sent to managers of 65 federally funded STD programs in state and local health departments. A similar survey was sent to 89 STD clinic managers in November 1997. RESULTS: The response rate among program managers was 97% (63/65). Forty-eight percent considered hepatitis B prevention a program responsibility; 21% had developed and distributed written policies to prevent hepatitis B through vaccination; and 27% had developed policies to encourage hepatitis B education activities. The response rate among clinic managers was 82% (73/89). Forty-five percent reported that their STD clinics had implemented policies recommending hepatitis B vaccination and health education activities. Program managers and clinic managers reported that lack of funding to cover the cost of the vaccine, and lack of resources to provide prevaccination counseling, administer vaccine, and track clients for vaccine series completion were the primary barriers to the implementation of hepatitis B vaccination programs. CONCLUSIONS: To enhance hepatitis B vaccination in STD clinics, existing funding sources must be accessed more effectively. Supplemental funding mechanisms for the cost of vaccine and resources for implementing vaccination programs also need to be identified. Additionally, STD clinics and programs should continue to propose and implement hepatitis B vaccination policies.

Adolescent↗
PubMed2001

Prevalence of metronidazole-resistant Trichomonas vaginalis in a gynecology clinic.

OBJECTIVE: To determine the prevalence of in vitro resistance to metronidazole among unselected isolates of Trichomonas vaginalis and correlate in vitro findings with response to metronidazole therapy. STUDY DESIGN: Vaginal fluid from women attending a gynecology clinic at an urban hospital was cultured, isolates were tested for in vitro resistance to metronidazole, and these results were correlated with therapeutic outcome. RESULTS: Among 911 women, T vaginalis was detected by culture in 82 (9.0%). Of the 82 isolates, 2 (2.4%; 95% CI, 0.3-8.5%) had low-level in vitro resistance (minimum lethal concentration, 50 micrograms/mL). Women with positive wet mount examinations were treated with metronidazole, 2 g, once and asked to return in one week. Of the 42 infected women agreeing to return for a repeat examination and culture, 26 (61.9%) did, and all (including one woman with a resistant isolate) were cured. CONCLUSION: Isolates of T vaginalis resistant to metronidazole occur widely throughout the United States. Although the in vitro susceptibility of T vaginalis to metronidazole has been very poorly studied, our study is consistent with a decade-old prevalence estimate of in vitro resistance (5%), and suggests that high-level resistance is uncommon. This study confirmed, in the absence of reinfection, the continuing clinical effectiveness of single-dose metronidazole for the large majority of trichomoniasis cases.

Adult↗
PubMed2001

Poly(ADP-ribose) polymerase-1 regulates the stability of the wild-type p53 protein.

We investigated the interaction between poly(ADP-ribose) polymerase-1 (PARP-1) and the product of the tumor suppressor gene p53 using two different approaches. In the first approach, we used primary and immortalized cells derived from wt and PARP-1 -/- mice. We examined whether PARP-1 deficiency would affect the expression of the wild-type (wt) p53 protein. The inactivation of the PARP-1 gene markedly affected the constitutive expression of the wt p53 protein. Interestingly, only the regularly spliced form of wt p53 was reduced to a barely detectable level in consequence to an approximately 8-fold shortening of its half-life, whereas the level of alternatively spliced p53 remained unchanged. Moreover, reconstitution of cells lacking the PARP-1 gene with the human counterpart restored the normal stability of the regularly spliced p53 protein. In the second approach, we performed experiments with c-Ha-ras transformed primary rat cells overexpressing the p53135val mutant alone or in combination with PARP-1. The advantage of this temperature sensitive p53135val mutant is its oncogenic character at 37 degrees C, connected with cytoplasmic localization of p53, and its tumor suppressor activity at 32 degrees C, accompanied by p53 translocation into the nucleus. No noticeable differences in proliferation and G1 accumulationwere observed between cells expressing p53135val with or without PARP-1. On the other hand, a comparison of the recovery of G1 arrested cells after a shift up to 37 degrees C for both cell lines showed dramatic differences in the kinetics. While cells expressing p53135val rapidly reached the characteristic S-phase level after a shift up to basal temperature, cells additionally expressing PARP-1 rested in G1 despite the temperature elevation. This coincided with exclusively cytoplasmic p53 protein in cells expressing p53135val and predominantly nuclear localization of p53 in p53135val +PARP-1 cells, as evidenced by immunostaining. Determination of the p53 level during the maintenance of cells at 32 degrees C revealed a marked decrease in the level of p53 in cells expressing p53135val alone, whereas in cells coexpressing PARP-1, the level of p53 remained largely unaffected. This indicates that the stability of wild-type p53 greatly differed between both cell lines. Furthermore, the inhibition of PARP-1 activity in G1 arrested cells by 3-aminobenzamide abolished its stabilizing effect on the wild-type p53 protein. Taken together, our results indicate that PARP-1 regulates the stability of the wt p53 protein and that its enzymatic activity is necessary for this stabilizing action.

Alternative Splicing↗
PubMed2001

Therapeutic approach in pulmonary mycetoma. Analysis of 27 patients.

BACKGROUND: Pulmonary mycetoma is a characteristic clinical-radiological lesion due to colonization of aspergillus or candida species in pre-existing pulmonary cavities following a number of diseases. METHODS: We revisited 27 records of such admitted patients (19 M, 8 F; range age 16-27 yrs) analysing diagnostic approach and therapy. Predisposing conditions were sequelae of tuberculosis or lung abscess, bronchiectasis, bullous emphysema, leukaemia/ lymphoma, diabetes mellitus, corticosteroids and/or immunosuppressant administration and antiblastic chemotherapy. All patients had a characteristic chest X-ray and the most common symptoms were cough and haemoptysis. Diagnosis of pulmonary mycetoma was based on positive sputum culture for aspergillus or candida species and/or positive result for aspergillus precipitin test. Eleven patients received only medical treatment, eight pts only a surgical one and eight patients both medical and surgical ones. Antifungal drugs administered were itraconazole or amphotericin B or fluconazole. RESULTS: In the follow-up, six out of eleven patients who had received only medical treatment, cannot be found; five patients or their relatives were interviewed by phone: two of them enjoyed good health and three had died. Sixteen patients underwent thoracic surgery and one of them died because of postsurgical complications. In the follow-up, only nine patients out of this last group were interviewed by phone 2 to 8 years after surgery: seven of them enjoyed good health while two patients had died because of disease not related to pulmonary mycetoma. CONCLUSIONS: Aspergilloma treatment is related to the extension of disease and clinical conditions of patients but surgical resection associated with drug administration, when possible, is the treatment of choice.

Adolescent↗
PubMed2000

N-Acetylcysteine counteracts erythrocyte alterations occurring in chronic obstructive pulmonary disease.

A key role has been proposed for reactive oxygen species (ROS) in chronic obstructive pulmonary disease (COPD). Aim of the present work was to evaluate possible implications of ROS in the integrity and function of the cell type mainly involved in oxygen uptake and delivery to the peripheral tissues: the erythrocyte. Red blood cells (RBCs) were thus collected from blood samples from COPD patients. Furthermore, blood samples from the same patients treated with the antioxidizing drug of widespread use in such disease i.e., N-acetylcysteine (NAC), were also considered. Morphometric and analytical cytology studies were then conducted. We report herein that: (i) alterations of RBC ultrastructure were detectable in RBCs from COPD patients, that (ii) relevant changes of spectrin cytoskeleton and glycophorin expression were also found and that (iii) NAC treatment was capable of significantly counteracting these changes. These results are consistent with a reappraisal of the role of RBCs in this disease.

Acetylcysteine↗