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Biomedical subjects

M Klein

Publications and source records attributed to M Klein.

At least 55 records · Page 3Linked to original sources
PubMed2003

[Esthetic rehabilitation of rhinophyma].

BACKGROUND: Rhinophyma is an uncommon progressively disfiguring process of the nose which occurs most often in middle-aged white men. The supposed association with increased alcohol abuse often leads to psychological problems for the person concerned. PATIENTS AND METHODS: We describe ten cases of patients with slowly progressive tumorous deformation of the nose. They were treated with a stepwise surgical approach consisting of tangential excision for debulking, sculpting with scissors, and finally contouring by dermabrasion. RESULTS: An esthetically pleasing result was achieved in all cases, making social reintegration for the patients possible. In the follow-up of at least 12 months no recurrence was seen and no scars occurred.

Combined Modality Therapy↗
PubMed2003

Quality of life and understanding of disease status among cancer patients of different ethnic origin.

Patients managed in European or North American cancer centres have a variety of ethnic backgrounds and primary languages. To gain insight into the impact of ethnic origin, we have investigated understanding of disease status and quality of life (QoL) for 202 patients. Patients completed questionnaires in their first language (52 English, 50 Chinese, 50 Italian, 50 Spanish or Portuguese), including the Functional Assessment of Cancer Therapy - General (FACT-G) QoL instrument, questions about disease status, expectations of cure and the language and/or type of interpretation used at initial consultation. Physicians also evaluated their status of disease and expectation of cure, and performance status was estimated by a trained health professional. The initial consultation was usually provided in English (except for 32% of Chinese-speaking patients); interpretation was provided by a family member for 34% of patients with limited English proficiency (LEP) and by a bilingual member of staff for 21%. Patients underestimated their extent of disease and overestimated their probability of cure (P=0.001 and <0.0001, respectively). Estimates of probability of cure by the English speakers were closer to those of their physicians than the other groups (P=0.02). English-speaking patients reported better and Italian-speaking patients poorer overall QoL (P<0.001 for Italian vs other groups). Performance status was correlated with QoL and most closely related with the extent of disease. Understanding of cultural differences is important for optimal management of patients with cancer.

Activities of Daily Living↗
PubMed2003

PET-based molecular imaging in neuroscience.

Positron emission tomography (PET) allows non-invasive assessment of physiological, metabolic and molecular processes in humans and animals in vivo. Advances in detector technology have led to a considerable improvement in the spatial resolution of PET (1-2 mm), enabling for the first time investigations in small experimental animals such as mice. With the developments in radiochemistry and tracer technology, a variety of endogenously expressed and exogenously introduced genes can be analysed by PET. This opens up the exciting and rapidly evolving field of molecular imaging, aiming at the non-invasive localisation of a biological process of interest in normal and diseased cells in animal models and humans in vivo. The main and most intriguing advantage of molecular imaging is the kinetic analysis of a given molecular event in the same experimental subject over time. This will allow non-invasive characterisation and "phenotyping" of animal models of human disease at various disease stages, under certain pathophysiological stimuli and after therapeutic intervention. The potential broad applications of imaging molecular events in vivo lie in the study of cell biology, biochemistry, gene/protein function and regulation, signal transduction, transcriptional regulation and characterisation of transgenic animals. Most importantly, molecular imaging will have great implications for the identification of potential molecular therapeutic targets, in the development of new treatment strategies, and in their successful implementation into clinical application. Here, the potential impact of molecular imaging by PET in applications in neuroscience research with a special focus on neurodegeneration and neuro-oncology is reviewed.

Alzheimer Disease↗
PubMed2003

Immunogenicity of a recombinant human immunodeficiency virus (HIV)-canarypox vaccine in HIV-seronegative Ugandan volunteers: results of the HIV Network for Prevention Trials 007 Vaccine Study.

In the first preventative human immunodeficiency virus (HIV) vaccine study to be carried out in Africa, 40 HIV-seronegative Ugandan volunteers were randomly assigned to receive a canarypox vector containing HIV-1 clade B (env and gag-pro) antigens (ALVAC-HIV; n = 20), control vector containing the rabies virus glycoprotein G gene (n = 10), or saline placebo (n = 10). Cytotoxic T lymphocyte activity against target cells expressing clade A, B, and D antigens was assessed using standard chromium-release and confirmatory interferon-gamma enzyme-linked immunospot (ELISPOT) assays. Neutralizing antibody responses to cell line-adapted strains and primary isolates in all 3 clades were also tested. Twenty percent of vaccine recipients generated detectable cytolytic responses to either Gag or Env, and 45% had vaccine-induced HIV-specific CD8(+) T cell responses, as measured by the ELISPOT assay. In contrast, only 5% of the control group had vaccine-specific responses. Neutralizing antibodies against primary and laboratory-adapted HIV-1 clade B strains were seen in 10% and 15% of vaccine recipients, respectively, but responses against clades A and D were not detected. Although the immunogenicity of this clade B-based vaccine was low, ALVAC-HIV elicited CD8(+) T cell responses with detectable cross-activity against clade A and D antigens in a significant proportion of vaccine recipients.

AIDS Vaccines↗
PubMed2003

[Catheter ablation of ectopic atrial tachycardia by electrical pulmonary vein disconnection].

We report a 25-year-old female patient with a long history of symptomatic paroxysmal supraventricular tachycardia. Electroanatomic activation mapping demonstrated a focal tachycardia originating in the right upper pulmonary vein, 3 cm distal to the ostium. Due to the recent experiences in the management of focal atrial fibrillation with catheter ablation, direct ablation applied inside the pulmonary vein was avoided. Instead, an electrical disconnection of the pulmonary musculature from the left atrium guided by a circumferential 10-electrode mapping catheter was performed. The patient has since been asymptomatic during follow-up.

Adult↗
PubMed2003

[Advantages of using robotic Da Vinci system for unilateral adrenalectomy: early results].

STUDY AIM: The goal of this study was to report the early results of unilateral transperitoneal adrenalectomy using robotic Da Vinci system, and to compare them to the results of the laparoscopic standard adrenalectomy. METHODS: Prospective study included all patients operated on for unilateral laparoscopic or robotic adrenalectomy from November 2000 to November 2002. RESULTS: Twenty-eight patients underwent unilateral adrenalectomy using either standard laparoscopy (14 patients) or robotic Da Vinci system (14 patients). Mean duration of robotic adrenalectomy seemed to be longer than standard laparoscopy (111 vs. 83 min; P = 0.057). This tendency decreased while surgeons' experience was increasing. Mean duration of operating room activity was similar for both types of surgery. Peroperative events without conversion, conversion rate (7%), drainage, morbidity (21%), duration of hospitalisation were similar for both types of surgery. Duration of standard laparoscopic adrenalectomy was positively correlated to patients body mass index. This correlation was absent in patients operated on by robotic Da Vinci system. CONCLUSION: This preliminary study found no objective data demonstrating that robotic Da Vinci system was superior to standard laparoscopic approach for unilateral adrenalectomy. However, we think that it is necessary to continue further evaluation of this system to demonstrate its possible superiority.

Adrenalectomy↗
PubMed2003

Self-diffusion measurements by a constant-relaxation method in strongly inhomogeneous magnetic fields.

The simple pulse sequence thetax-tau1-2thetay-tau1+tau2-2thetay-tau2-Hahn echo used to measure the self-diffusion coefficient D under constant-relaxation condition, i.e., for tau1+tau2=const. was investigated in the presence of strongly inhomogeneous static as well as radiofrequency magnetic fields. The encoding of the Hahn-echo amplitude by the pulse flip angle and diffusion was evaluated by taking into account the spatial distribution of the off-resonance field, the strength and orientation of the local field gradients, and the pulse flip angles by a computer simulation program. As input files, this program uses maps of static and radiofrequency fields, and the D coefficient can be evaluated from the time dependence of the Hahn-echo amplitude. The method was applied to a mobile one-sided NMR sensor, NMR-MOUSE with a bar magnet by measuring D for a series of liquids with different viscosities. The method was shown to be particularly useful for measuring D of solvents in elastomers without the need for measurements of the transverse relaxation rates. The self-diffusion coefficient of toluene in a series of crosslinked natural rubber samples was measured and correlated with the crosslink density. Finally, the method was applied to measure the diffusion anisotropy of free water in bovine Achilles tendon.

Algorithms↗
PubMed2003

Interleukin-7 levels may predict virological response in advanced HIV-1-infected patients receiving lopinavir/ritonavir-based therapy.

OBJECTIVES: To examine the relationship between levels of the T-cell regulatory cytokine interleukin-7 (IL-7) and CD4 cell counts during immune reconstitution and to assess its prognostic value in advanced HIV-1-infected patients receiving lopinavir/ritonavir-based therapy. METHODS: Thirty-six HIV-1-infected adults who completed 48 weeks of follow-up visits were included in this prospective study. Patients having failed two or more antiretroviral therapy regimens were treated with lopinavir/ritonavir-based therapy. An enzyme-linked immunosorbent assay was used to determine IL-7 plasma levels, flow cytometry was used to analyse cell surface antigens, and polymerase chain reaction was used to quantify plasma HIV-1. RESULTS: Pretreatment IL-7 levels were elevated in all patients (mean 11.0 pg/mL) and were negatively correlated with CD4 cell counts and age (r=-0.59, P<0.001 and r=-0.57, P<0.001, respectively). During the course of treatment, IL-7 levels decreased by 34% while CD4 cell numbers progressively increased by 88%. Multivariate regression analysis showed that only pretreatment IL-7 levels predicted viral load at 48 weeks when controlling for baseline CD4 cell counts, viral load and patient demographics. CONCLUSIONS: These findings are consistent with regulation of T-cell recovery by IL-7, and suggest that IL-7 measurements might be used to predict virological response.

Adult↗
PubMed2003

Excretion measurement of porphyrins and their precursors after topical administration of 5-aminolaevulinic acid for fluorescence endoscopy in head and neck cancer.

5-Aminolevulinic acid (5-ALA) is a useful agent to enhance the detection of early epithelial lesions in head and neck cancers. It is applied either topically or systemically and converted intracellular into photosensitive protoporphyrin IX (PpIX). By ultraviolet light illumination malignant and fast proliferating lesions are detected by a characteristic red fluorescence and delineated by the bluish fluorescence of healthy tissue. To assess the elimination patterns 5-ALA, porphobilinogen (PBG) and porphyrin were measured 12h and 36h after administration in urine, 12h and 24h after examination in blood and in feces 12h after endoscopy. 5-ALA was applied either by inhalation (250 mg) or mouth rinse (200 mg). After both administration routes, excretion levels in urine returned to background levels within 12 hours after administration and only in feces values are slightly increased for PpIX and total porphyrin. Concentrations in erythrocytes were elevated, but not in plasma. No side effects were observed. According to our results the topical administration of 5-ALA is a useful method with satisfying fluorescence imaging results. Levels of metabolites in urine and plasma return to normal within 12 hours so that skin photosensitization can be neglected.

Administration, Topical↗
PubMed2002

Effect of radiotherapy and other treatment-related factors on mid-term to long-term cognitive sequelae in low-grade gliomas: a comparative study.

BACKGROUND: Because survival benefits of treatment with radiotherapy are questionable and such treatment can cause substantial damage to the brain over time, the optimum management strategy for low-grade gliomas remains controversial. We aimed to identify the specific effects of radiotherapy on objective and self-reported cognitive function, and on cognitive deterioration over time, in patients with low-grade gliomas treated with early radiotherapy. METHODS: 195 patients with low-grade glioma (of whom 104 had received radiotherapy 1-22 years previously) were compared with 100 low-grade haematological patients and 195 healthy controls. Our analyses aimed to differentiate between the effects of the tumour (eg, disease duration, lateralisation) and treatment effects (neurosurgery, radiotherapy, antiepileptic drugs) on cognitive function and on relative risk of cognitive disability. FINDINGS: Low-grade glioma patients had lower ability in all cognitive domains than did low-grade haematological patients, and did even less well by comparison with healthy controls. Use of radiotherapy was associated with poorer cognitive function; however, cognitive disability in the memory domain was found only in radiotherapy patients who received fraction doses exceeding 2 Gy. Antiepileptic drug use was strongly associated with disability in attentional and executive function. INTERPRETATION: Our findings suggest that the tumour itself has the most deleterious effect on cognitive function and that radiotherapy mainly results in additional long-term cognitive disability when high fraction doses are used. Additionally, the effects of other medical factors, especially antiepileptic drug use, on cognitive function in glioma patients deserve attention.

Adult↗
PubMed2002

Radiotherapy-induced cerebral abnormalities in patients with low-grade glioma.

Abnormalities on CT or MRI and neuropsychological performance in patients with low-grade glioma, with (n = 23) or without (n = 16) prior cerebral radiotherapy, were evaluated. Cerebral atrophy was observed in 14 of 23 patients (61%) treated with prior radiotherapy, and in 1 of 16 patients (6%) without prior radiotherapy. White matter abnormalities were observed in six patients, all of whom were treated with prior radiotherapy. These radiologic cerebral abnormalities correlated with cognitive performance.

Adult↗
PubMed2002

Tumor progression, histologic grading and DNA-ploidy as predictive factors of lymphogenous metastasis in primary carcinoma of the Fallopian tube.

UNLABELLED: The bad prognosis of primary carcinoma of the Fallopian tube (FTC), with 5-year overall survival rates of only 35%, is particularly ascribed to lymphogenous metastasis. Yet, we know very little on the pathophysiologic factors on which this lymphogenous metastasis is based. The present study, therefore, aims at evaluating the influence of intra-abdominal tumor progression and tumor-cell anaplasia on lymphogenous metastasis in FTC. We studied 41 cases of FTC, who had been subjected to radical lymphadenectomy during primary operation in a retrospective analysis. Staging was done by International Federation of Gynecology and Obstetrics-classification. Histologic grading and nuclear DNA-content (DNA-index) were used for evaluating tumor-cell anaplasia. Histologic grading discriminated between highly differentiated (G1), moderately dedifferentiated (G2), and dedifferentiated (G3) tumors. According to their DNA-indices, tumors were separated into three groups: DNA-index < or =1.1 (euploid cases), DNA-indices between 1.1 and 2.0 (cases of intermediate ploidy), and DNA-index >2.0 (aneuploid cases). The overall incidence of lymph node metastases was 43.9%. There was no correlation between histologic grading and DNA-index (P=0.98). Lymphogenous metastasis set in after the tumor had transgressed the tube (intra-abdominal stage II). Further intra-abdominal tumor progression (including omentum, liver, or peritoneum) significantly increases the incidence of lymph node metastases (P=0.02). There was only a single G1-tumor that had already disseminated into the lymph, all other cases of lymph node metastases were found in G2- or G3-tumors. DNA-index and the extent of lymphogenous metastases were not found to be correlated (P=0.74). CONCLUSIONS: The extent of lymphogenous metastases in FTC depends above all on intra-abdominal tumor progression. This fact has clinical consequences as the indication for lymphadenectomy can be obtained directly during operation. The results of histologic grading are of no impact on the surgical proceedings; the determination of DNA-ploidy is negligible.

Adult↗
PubMed2002

Ultra-relativistic electrons in Jupiter's radiation belts.

Ground-based observations have shown that Jupiter is a two-component source of microwave radio emission: thermal atmospheric emission and synchrotron emission from energetic electrons spiralling in Jupiter's magnetic field. Later in situ measurements confirmed the existence of Jupiter's high-energy electron-radiation belts, with evidence for electrons at energies up to 20[?]MeV. Although most radiation belt models predict electrons at higher energies, adiabatic diffusion theory can account only for energies up to around 20[?]MeV. Unambiguous evidence for more energetic electrons is lacking. Here we report observations of 13.8[?]GHz synchrotron emission that confirm the presence of electrons with energies up to 50[?]MeV; the data were collected during the Cassini fly-by of Jupiter. These energetic electrons may be repeatedly accelerated through an interaction with plasma waves, which can transfer energy into the electrons. Preliminary comparison of our data with model results suggests that electrons with energies of less than 20[?]MeV are more numerous than previously believed.

Journal Article↗
PubMed2002

[Does the size of pheochromocytoma influence the results of its laparoscopic excision?].

BACKGROUND: The tumor size is considered as a limitation for laparoscopic adrenalectomy. The aim of this study was to assess diagnostic characteristics, hemodynamic modifications, and outcome of intraperitoneal laparoscopic adrenalectomy according to the size of pheochromocytoma. METHODS: Retrospective study from January 1997 to December 2000. Results were evaluated according to the size of pathologic study (< or > or = 5 cm). RESULTS: Forty two patients underwent laparoscopic adrenalectomy during this period. Among them, 11 (26%) were operated on for adrenal pheochromocytoma (6 patients < 5 cm and 5 patients > or = 5 cm). Preoperative systolic hypertension was 138 mmHg and 178 mmHg respectively (p = 0.01). Urinary metanephrine/normetanephrine rate was 1.259 and 0.268 respectively (p = 0.08). Capsular tumor effraction rate was 27%. Tumor size was 37% larger than that estimated by CT scan (24% versus 52%). Mean hospital stay was 10 days and 8 days respectively. Morbidity and mortality were 18% and 0%. All these criteria were not statistically significant among the two groups of patients. CONCLUSIONS: Pheochromocytoma size > or = 5 cm do not modify outcome of patients but is responsible for preferential noradrenaline secretion and stronger hemodynamic modifications. Tumor fragmentation rate and CT scan size underestimation seem important in this group of patients. These characteristics have to be integrated to improve laparoscopic adrenalectomy outcome of patients with pheochromocytoma > or = 5 cm.

Adrenal Gland Neoplasms↗
PubMed2002

ALVAC-SIV-gag-pol-env-based vaccination and macaque major histocompatibility complex class I (A*01) delay simian immunodeficiency virus SIVmac-induced immunodeficiency.

T-cell-mediated immune effector mechanisms play an important role in the containment of human immunodeficiency virus/simian immunodeficiency virus (HIV/SIV) replication after infection. Both vaccination- and infection-induced T-cell responses are dependent on the host major histocompatibility complex classes I and II (MHC-I and MHC-II) antigens. Here we report that both inherent, host-dependent immune responses to SIVmac251 infection and vaccination-induced immune responses to viral antigens were able to reduce virus replication and/or CD4+ T-cell loss. Both the presence of the MHC-I Mamu-A*01 genotype and vaccination of rhesus macaques with ALVAC-SIV-gag-pol-env (ALVAC-SIV-gpe) contributed to the restriction of SIVmac251 replication during primary infection, preservation of CD4+ T cells, and delayed disease progression following intrarectal challenge exposure of the animals to SIV(mac251 (561)). ALVAC-SIV-gpe immunization induced cytotoxic T-lymphocyte (CTL) responses cumulatively in 67% of the immunized animals. Following viral challenge, a significant secondary virus-specific CD8+ T-cell response was observed in the vaccinated macaques. In the same immunized macaques, a decrease in virus load during primary infection (P = 0.0078) and protection from CD4 loss during both acute and chronic phases of infection (P = 0.0099 and P = 0.03, respectively) were observed. A trend for enhanced survival of the vaccinated macaques was also observed. Neither boosting the ALVAC-SIV-gpe with gp120 immunizations nor administering the vaccine by the combination of mucosal and systemic immunization routes increased significantly the protective effect of the ALVAC-SIV-gpe vaccine. While assessing the role of MHC-I Mamu-A*01 alone in the restriction of viremia following challenge of nonvaccinated animals with other SIV isolates, we observed that the virus load was not significantly lower in Mamu-A*01-positive macaques following intravenous challenge with either SIV(mac251 (561)) or SIV(SME660). However, a significant delay in CD4+ T-cell loss was observed in Mamu-A*01-positive macaques in each group. Of interest, in the case of intravenous or intrarectal challenge with the chimeric SIV/HIV strains SHIV(89.6P) or SHIV(KU2), respectively, MHC-I Mamu-A*01-positive macaques did not significantly restrict primary viremia. The finding of the protective effect of the Mamu-A*01 molecule parallels the protective effect of the B*5701 HLA allele in HIV-1-infected humans and needs to be accounted for in the evaluation of vaccine efficacy against SIV challenge models.

Animals↗
PubMed2002

Automatic patient registration in computer assisted maxillofacial surgery.

In this paper, a new approach for patient registration in computer assisted maxillofacial surgery is presented. The method uses a unique structure of markers embedded in a reference frame for the automatic detection of the coordinate system of the medical imaging data during the surgical intervention. With the new method, the inaccurate and time consuming process of manually identifying markers in the data volume and manually teaching them to a navigation system can be replaced. The method and algorithms for the automatic marker detection are described in this paper. Experiments with 45 data sets of patients proove the robustness, usability and safety of the new method. The method has been integrated into the navigation system RoboDent for dental implant surgery.

Algorithms↗