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Biomedical subjects

T Weiss

Publications and source records attributed to T Weiss.

At least 19 recordsLinked to original sources
PubMed2006

Percutaneous absorption of aromatic amines in rubber industry workers: impact of impaired skin and skin barrier creams.

BACKGROUND: Several aromatic amines (AA) could cause bladder cancer and are an occupational hygiene problem in the workplace. However, little is known about the percutaneous absorption of chemicals via impaired skin and about the efficacy of skin protection measures to reduce internal exposure. AIMS: To determine the impact of skin status and of skin protection measures on the internal exposure to AA in workers manufacturing rubber products. METHODS: 51 workers occupationally exposed to aniline and o-toluidine were examined. The workplace conditions, risk factors for skin and the use of personal protective equipment were assessed by means of a self-administered questionnaire. The skin of hands and forearms was clinically examined. Exposure to aniline and o-toluidine was assessed by ambient air and biological monitoring (analyses of urine samples and of haemoglobin adducts). RESULTS: Haemoglobin-AA-adduct levels in workers with erythema (73%) were significantly higher (p<0.04) than in workers with healthy skin (mean values: aniline 1150.4 ng/l vs 951.7 ng/l, o-toluidine 417.9 ng/l vs 118.3 ng/l). The multiple linear regression analysis showed that wearing gloves significantly reduced the internal exposure. A frequent use of skin barrier creams leads to a higher internal exposure of AA (p<0.03). However, the use of skincare creams at the workplace was associated with a reduced internal exposure (p<0.03). From these findings we assume that internal exposure of the workers resulted primarily from the percutaneous uptake. CONCLUSIONS: The study demonstrates a significantly higher internal exposure to AA in workers with impaired skin compared with workers with healthy skin. Daily wearing of gloves efficiently reduced internal exposure. However, an increased use of skin barrier creams enhances the percutaneous uptake of AA. Skincare creams seem to support skin regeneration and lead to reduced percutaneous uptake.

Adult↗
PubMed2006

Successful treatment of lichen amyloidosis with combined bath PUVA photochemotherapy and oral acitretin.

Lichen amyloidosis (LA) is a chronic, pruritic skin disorder characterized by brownish-grey papules on extensor surfaces of legs and rarely on the trunk. Thioflavin T-positive amyloid deposits are found in the papillary dermis of affected skin, which is the only organ involved. A variety of therapeutic regimens for lichen amyloidosis have been described; however, in many cases with only limited effect. We report on two patients with lichen amyloidosis with typical clinical symptoms not responding to local treatment. A combined regimen with bath psoralen ultraviolet A (PUVA) and oral acitretin was initiated, resulting in nearly complete resolution of the papules and impressive relief from the severe pruritus. The beneficial response has persisted for 8 months. The suggested combined therapy with bath PUVA photochemotherapy and oral acitretin represents an efficacious and practical treatment modality for lichen amyloidosis with long-lasting effects.

Acitretin↗
PubMed2006

[Stimulation of tiny skin areas for selective stimulation of C fibres].

BACKGROUND: It has been found difficult to stimulate the primary C-fibre afferents separately from those of Adelta fibres. A necessary and sufficient condition for the investigation of the C-fibre system is the selective stimulation of C fibres without activation of Adelta fibres. The stimulation of tiny skin areas allows such a selective activation of C fibres. METHODS AND RESULTS: The main aspects of the method for stimulation of tiny skin areas as well as some results obtained by this method are reported here. The application of this method is compared with applications of other methods that allow an investigation of central processing of human C-fibre input. CONCLUSION: The stimulation of tiny skin areas represents a simple method for selective stimulation of C fibres.

Afferent Pathways↗
PubMed2006

A reticular variant of elastolytic giant cell granuloma.

An 80-year-old man presented with a distinctive reticular form of elastolytic giant cell granuloma (EGCG). This represents a rare subset of EGCG, thus belonging to a larger group of granulomatous skin diseases with poorly understood pathogenesis. The patient exhibited numerous erythematous to brownish, sharply demarcated patches of reticulate appearance with partial central atrophy and nonelevated margins, which involved the trunk and especially chest, shoulders, upper back and arms. Skin biopsy revealed a granulomatous infiltrate with multinucleate histiocytes containing remnants of elastic fibres in conjunction with a significant loss of elastic fibres throughout the dermis. There is little published information on treatment, which remains unsatisfactory.

Aged, 80 and over↗
PubMed2006

Circulating endothelial progenitor cells are inversely correlated with the median oxygen tension in the tumor tissue of patients with cervical cancer.

Tumor hypoxia leads to adaptive responses in cancer cells, including an induction of vasculogenesis initiated by circulating endothelial progenitor cells (EPCs) and circulating endothelial cells (CECs). The aim of the present study was to correlate the number of EPCs and CECs with the oxygenation of cervical cancer. Blood concentrations of EPCs were detected by FACS analysis with antibodies for CD34 and vascular endothelial growth factor receptor 2 (VEGFR2). CECs were evaluated by double staining for 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine-labeled acetylated low density lipoprotein (Di-LDL) and lectin in a cell culture assay. Ten patients with cervical cancer were compared with ten healthy volunteers. Intratumoral oxygen tension was assessed polarographically with the computerized Eppendorf histography system. Analysis of CEC numbers revealed no difference between patients and controls. However, patients had lower concentrations of CD34-positive hematopoietic stem cells (HSCs) but a significantly higher fraction of EPCs related to the number of HSCs (1.09% versus 0.53%). This fraction was significantly inversely correlated to the median oxygen tension (r = -0.74, p = 0.015). Our study shows for the first time a significant inverse correlation between the fraction of EPCs and intratumoral oxygen tension. We conclude that the fraction of EPCs should be further evaluated as a useful and convenient marker in the prediction of tumor tissue oxygenation.

Endothelium, Vascular↗
PubMed2005

[Neurological complications and loss of efficacy with intrathecal pain therapy].

In a new guideline issued by the German Association for the Study of Pain, intrathecal opioid therapy is described as proven to be effective with relatively few side effects. We reviewed this statement by analysis of the available literature and critical evaluation of the clinical course in a few of our own patients (n=3). In these cases (as well as in a further eight patients), explantation and a switch to oral opioids led to distinctly better alleviation of pain and abatement of the unwanted effects. The problems we discuss do not appear to be rare instances, but by all means complications that are frequently described. The long-term efficacy of intrathecal opioids has not been adequately verified; moreover, their potency is not high. The frequency of undesired events is comparable to that of oral opioid medication, but serious neurological complications are possible. To avoid dose escalations and to recognize neurological complications in time, diligent monitoring by the surgeon or an experienced pain center is essential.

Administration, Oral↗
PubMed2005

Dilatation of the entire thoracic aorta in patients with bicuspid aortic valve: a magnetic resonance angiography study.

BACKGROUND: The presence of a bicuspid aortic valve (BAV) might be associated with a progressive dilatation of the aortic root and ascending aorta. However, involvement of the aortic arch and descending aorta has not yet been elucidated. PATIENTS AND METHODS: Magnetic resonance angiography (MRA) was used to assess the diameter of the ascending aorta, aortic arch, and descending aorta in 28 patients with bicuspid aortic valves (mean age 30 +/- 9 years). RESULTS: Patients with BAV, but without significant aortic stenosis or regurgitation (n = 10, mean age 27 +/- 8 years, n.s. versus control) were compared with controls (n = 13, mean age 33 +/- 10 years). In the BAV-patients, aortic root diameter was 35.1 +/- 4.9 mm versus 28.9 +/- 4.8 mm in the control group (p < 0.01). The diameter of the ascending aorta was also significantly increased at the level of the pulmonary artery (35.5 +/-5.6 mm versus 27.0 +/- 4.8 mm, p < 0.001). BAV-patients with moderate or severe aortic regurgitation (n = 18, mean age 32 +/- 9 years, n.s. versus control) had a significant dilatation of the aortic root, ascending aorta at the level of the pulmonary artery (41.7 +/- 4.8 mm versus 27.0 +/- 4.8 mm in control patients, p < 0.001) and, furthermore, significantly increased diameters of the aortic arch (27.1 +/- 5.6 mm versus 21.5 +/- 1.8 mm, p < 0.01) and descending aorta (21.8 +/- 5.6 mm versus 17.0 +/- 5.6 mm, p < 0.01). CONCLUSIONS: The whole thoracic aorta is abnormally dilated in patients with BAV, particularly in patients with moderate/severe aortic regurgitation. The maximum dilatation occurs in the ascending aorta at the level of the pulmonary artery. Thus, we suggest evaluation of the entire thoracic aorta in patients with BAV.

Adult↗
PubMed2004

Trans-placental exposure of neonates to acrylamide--a pilot study.

OBJECTIVES: Acrylamide (AA) (CAS No 79-06-1) has most recently been identified as a food-borne toxicant generated during the heating process of starch-containing foods. It was the aim of the present study to investigate the trans-placental exposure of newborn infants to this possible human carcinogen by analysis of the specific haemoglobin adduct of AA ( N-2-carbamoylethylvaline, AAV) in the blood of mothers and the corresponding umbilical cord blood of neonates as a parameter of biochemical effects. METHODS: We investigated the blood of 11 women advanced in pregnancy (one smoker, ten non-smokers) and the corresponding umbilical cord blood of neonates for the N-terminal haemoglobin adducts of AA (AAV) and the smoking-specific adduct of acrylonitrile (CAS No 107-13-1) ( N-cyanoethylvaline, CEV). The limit of detection (LOD) was 5 pmol/g globin for AAV and 4 pmol/g globin for CEV. RESULTS: AAV could be determined in all blood samples of the mothers (median 21 pmol/g globin, range 18-104 pmol/g globin) as well as in the umbilical cord blood of neonates (median 10 pmol/g globin, range 6-43 pmol/g globin). The highest values were detected in the blood of the smoking mother and her child. CEV was detected only in the blood of the smoking mother (185 pmol/g globin) and the corresponding umbilical cord blood (69 pmol/g globin). DISCUSSION: AAV adduct levels in non-smoking mothers and neonates showed a good correlation (r=0.859). The concentration of AA adducts in the blood of neonates is approximately 50% of the adduct level found in the blood of the mother. In view of the shorter life span of neonatal erythrocytes and the lower body weight of newborn infants, the relative internal dose of AA in neonates (in microgrammes per kilogramme body weight) must be assumed to be at least equal to that of the mother. Because of the high cell-replication rates during foetal development, trans-placental exposure of neonates to AA might raise concerns. Neonates of smoking mothers take up much higher doses of AA than those of non-smoking mothers.

Acrylamide↗
PubMed2004

[Use of beta blockers in cardiovascular diseases and bronchial asthma/COPD].

Numerous extensive, randomized clinical trials of beta-blockers have shown significant reduction of total mortality in patients with myocardial infarction and chronic heart failure. The life-saving therapy of myocardial infarction or chronic heart failure with beta-blockers, however, is often withheld from patients with COPD/asthma. Several studies demonstrate that especially patients with COPD would benefit from such a therapy due to their high cardiovascular risk profile. Recent meta-analyses show that cardioselective beta-blockers are well tolerated by these patients without causing relevant limitations in lung function. Present findings suggest that the mortality reduction of beta-blocker therapy may outweigh the risks in patients with COPD and possibly even in patients with mild asthma. Contraindications for beta-blockers include acute exacerbations and severe forms of COPD as well as moderate to severe asthma and the regular use of beta(2)-sympathomimetics. beta-Blocker therapy should be given with low initial doses on an individual basis after careful consideration of the benefit to risk ratio, preferably using cardioselective substances with proven mortality benefits for myocardial infarction and chronic heart failure.

Adrenergic beta-Antagonists↗
PubMed2002

Endothelial function in patients with peripheral vascular disease: influence of prostaglandin E1.

Peripheral arterial occlusive disease (PAOD) is characterized by atherosclerotic lesions in large vessels and disturbances on the microcirculatory level. In the local regulation of vascular tone and microvascular perfusion, vascular endothelium plays a key role. For many years prostaglandin E1 (PGE1) has been used for the treatment of PAOD. Because PGE1 has only moderate effects on blood flow other mechanisms may be relevant for the therapeutical efficacy. The aim of our pilot study was to evaluate endothelial function in patients with PAOD and to investigate the impact of PGE1 on endothelial-dependent vasodilation in peripheral vesselsIn 8 controls and in 8 patients with PAOD stage II, endothelial-dependent vascular responses of the femoral vessels to increasing doses of acetylcholine (30,60,90 microg/min) were determined by Doppler flow velocity measurements in the common femoral artery. Furthermore, vascular reactivity was evaluated before and immediately after intravenous infusion of 30 microg PGE1/30 min in patients. Endothelial-dependent vasodilation was significantly reduced in patients with PAOD compared to control subjects. Infusion of PGE1 neither increased blood flow in the common femoral artery nor endothelium-dependent vasodilation of peripheral resistance vessels as indicated by unchanged reaction to acetylcholine. In conclusion, endothelial function is impaired in patients with PAOD. Administration of PGE1 did not increase femoral artery blood flow or improve endothelial-dependent reactivity of peripheral resistance vessels in patients with PAOD. Therefore, beneficial effects of PGE1 in peripheral vascular disease cannot be attributed to an increase in blood supply or an improvement of endothelial-dependent vasodilation.

Aged↗
PubMed2001

Increased excitability in the primary motor cortex and supplementary motor area in patients with phantom limb pain after upper limb amputation.

Using functional magnetic resonance imaging and single slice FLASH technique, we investigated reorganization of the hand representation of the primary sensorimotor cortex (SMC) in 16 patients with upper extremity amputation. Patients were asked to perform finger tapping with the intact hand, repetitive eye closing and anteflexion of the amputation stump or intact shoulder. Six normal volunteers served as control. In the normal volunteers activations during shoulder anteflexion, finger tapping and eye closure were located within the central sulcus in a medio-lateral fashion. Patients demonstrated invasion of the face or shoulder representation into the hand representation of the amputated limb. Eight phantom limb pain patients showed significantly greater activation in SMC and supplementary motor area (SMA) in contrast to eight patients without phantom limb pain. We conclude, that different parts of the motor system are affected in patients with phantom limb pain--possibly in the sense of an up-regulation of excitability.

Adolescent↗