Search PubMed⌕ Search

Biomedical subjects

P Schmid

Publications and source records attributed to P Schmid.

At least 145 records · Page 8Linked to original sources
PubMed1994

Laboratory evaluations in HIV-1-associated cognitive/motor complex.

Laboratory tests can provide useful information about the presence and effects of HIV-1 in the CNS, but have thus far not yielded definitive diagnostic or prognostic markers of HIV-1-related cognitive and motor complex. The most clinically useful laboratory procedures are MR imaging and CSF examinations. The routine clinical use of MR imaging and CSF examinations, however, is still restricted to providing information for detecting and excluding secondary effects of HIV-1 infection. MR imaging and CT do not appear to be sensitive enough at current resolutions to provide early detection of HIV-1 CNS effects nor to follow disease progression. Several CSF variables are extremely promising as early markers of primary HIV-1 infection of the brain, and may provide preclinical indications for onset of treatment and for evaluation of treatment efficacy. These include CSF quinolinic acid levels, acid dissociated p24 antigen levels, neopterin or beta 2m, intrathecal IgG synthesis rate, and possibly quantitated PCR levels of HIV-1 viral load. Procedures such as nuclear magnetic resonance spectroscopy, SPECT, PET, computerized EEG, EP, and ERPs are all promising candidates for early detection or localization of HIV-1-related brain dysfunction, but at this time all must still be considered primarily research tools. Before any of these procedures can provide reliable diagnostic and prognostic information about primary HIV-1 neurologic disease, currently on-going longitudinal evaluations of large numbers of asymptomatic HIV-1-infected individuals as they progress to neurologically symptomatic disease must be completed. There is currently no laboratory marker in blood or CSF that definitively predicts the risk for HIV-1-associated cognitive/motor complex. HIV-1-associated cognitive/motor complex remains a clinical diagnosis, which is made on the basis of positive neurologic signs and symptoms and abnormal neuropsychological findings after other causes of neurologic disease are excluded. Laboratory measures, such as the electrophysiologic methods and some CSF variables, are likely to remain adjuncts to the diagnosis because, with few exceptions, they provide data that are nonspecific as to etiopathogenesis. Dynamic imaging, electrophysiologic methods, and CSF indices provide presumptive evidence for the presence of HIV-1-associated CNS damage, and with clinical and neuropsychological evidence, could be used to establish a new definition of primary HIV-1-associated CNS disease along the lines used in establishing a diagnosis of multiple sclerosis.(ABSTRACT TRUNCATED AT 400 WORDS)

AIDS Dementia Complex↗
PubMed1994

Isradipine increases platelet--low-density lipoprotein binding: evidence from ex-vivo studies in humans.

The effects of isradipine (2.5 mg twice daily) on platelet--radioiodine-labeled [123I] low-density lipoprotein (LDL) binding were measured in 16 hypertensive patients (mean age 46.2 +/- 10.7 years) with (cholesterol > 250 mg/dl; n = 8) and without (cholesterol < 200 mg/dl; n = 8) hypercholesterolaemia during 4 weeks of isradipine treatment after 4 weeks of pretreatment placebo followed by 2 weeks of post-treatment placebo periods. Radioligand LDL-binding studies revealed that isradipine induced a significant (p < 0.001) rise in maximum binding capacity (Bmax) from a mean of 1148.6 +/- 244.3 ng protein/10(9) platelets to a mean of 1262.3 +/- 204.1 ng protein/10(9) platelets [dissociation constant (Kd): 9.7 +/- 4.9 micrograms protein/ml before treatment vs 7.8 +/- 3.7 g protein/ml after treatment]. After the post-treatment placebo phase, both Bmax and Kd returned to baseline levels. When the hypercholesterolaemic patients were compared with the normocholesterolaemics, the former revealed a more pronounced increase in platelet [125I]-LDL-binding capacity. Correspondingly, the dissociation constant showed a significantly (p < 0.05) greater decrease. In accordance with these results, both total and LDL cholesterol were reduced after 4 weeks of therapy with significant (p < 0.03) rises through to the end of the post-treatment placebo period. It is suggested that the observed increase in high-affinity platelet--LDL binding with isradipine treatment reflects a state of decreased in-vivo platelet activation, an effect which may be of particular clinical value in hyperlipidaemic patients.

Adult↗
PubMed1994

Isradipine decreases the entry of radioiodine-labelled low-density lipoproteins into the arterial wall.

Experimental studies have demonstrated that isradipine significantly decreases the entry of radioiodine-labelled (125I) low-density lipoproteins (LDL) into the aorta. This study aimed to investigate whether similar effects could be detected in humans as well. Twelve patients (nine men and three women, aged from 35 to 53 years), all of whom had both hyperlipoproteinaemia (either type IIa or type IIb; mean total cholesterol: 296 +/- 25 mg/dl; mean LDL cholesterol: 208 +/- 22 mg/dl) and mild-to-moderate hypertension [mean systolic blood pressure (SBP): 149 +/- 12 mmHg; mean diastolic blood pressure (DBP): 104 +/- 4 mmHg] received isradipine (2 x 2.5 mg). Autologous radiolabelled (123I) LDL was reinjected and a gamma camera used to study the LDL kinetics before (at 20 min, 2 h and 20 h) and after (at the same time intervals) treatment with isradipine. Of interest were those arterial regions that are typically sites of atherosclerotic lesions (carotid artery, femoral artery). Results revealed three different types of LDL kinetics which were not altered by isradipine treatment. The quantitative LDL entry, however, was reduced by at least 4.7% with a maximum of 23.5% (p < 0.01). Only five vascular sites with type III kinetics were detected. These data suggest that isradipine may induce functional regression of atherosclerotic lesions.

Adult↗
PubMed1994

Influence of calcium antagonists on platelet function and vascular prostacyclin production.

It is suggested that calcium antagonists can counteract the process of atherogenesis by influencing different cellular mechanisms, for example, inhibiting cellular migration and proliferation, as well as by having beneficial effects on lipid metabolism and platelet function. In an assessment of the activity of different calcium antagonists in various platelet function tests and prostacyclin (PGI2) synthesis, amlodipine, diltiazem, felodipine, isradipine, nicardipine, nifedipine, nitrendipine and verapamil were tested in vitro for their effects on adenosine diphosphate (ADP)- or collagen-induced platelet aggregation, malondialdehyde (MDA) formation and vascular PGI2 production. Nitrendipine, isradipine and nicardipine were shown to inhibit both ADP- and collagen-induced platelet aggregation at the lowest concentration (0.5 microgram/ml). The half-maximum inhibiting concentration (IC50) of isradipine (4.78 +/- 0.36 micrograms/ml for ADP-induced platelet aggregation) was significantly (p < 0.01) lower than the IC50 of all the other drugs. Nitrendipine, with an IC50 of 44.2 +/- 5.32 micrograms/ml, and nicardipine, with an IC50 of 46.74 +/- 3.83 micrograms/ml, were respectively the second and third most effective compounds. Formation of MDA was also inhibited the most by isradipine, which exerted its inhibitory properties at one-fifth the concentration needed with the other agents: the IC50 of isradipine was 0.98 +/- 0.16 microgram/ml, which was significantly different (p < 0.05) compared with the second most effective agent, verapamil, which had an IC50 of 14.92 +/- 3.78 micrograms/ml. In-vitro PGI2 production was stimulated the most by isradipine as well, producing a significant (p < 0.01) increase to 417.8 +/- 47.6 pg/mg tissue/h (control: 296.4 +/- 17.6 pg/mg tissue/h) at a concentration of 0.5 microgram/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Diphosphate↗
PubMed1993

[Sarrazin allergy: a contribution to buckwheat allergy].

Buckwheat allergy is frequent in Asian countries such as Japan because of widespread use of buckwheat in food and bed furniture. In Switzerland such reactions are very rare and mostly due to ingested buckwheat in the form of pizoccheri and buckwheat bread. We describe 6 cases of allergic reactions due to buckwheat comprising urticaria (all pat.), quincke edema (4 pat.) and asthma (5 pat.). 4 patients reacted to ingestion of buckwheat, and 2 patients with occupational exposure were allergic to inhaled buckwheat. Sensitizations were proven in all patients by positive skin tests and specific IgE (RAST). Treatment consisted of strict allergen elimination.

Adult↗
PubMed1993

Injury induced expression of TGF-beta 1 mRNA is enhanced by exogenously applied TGF-beta S.

We have analysed and compared, by in situ hybridisation, the effects of exogenously applied TGF-beta s on expression of endogenous TGF-beta mRNAs in partial thickness thermal wounds in old and young mice. Although injury induced the expression of TGF-beta 1 mRNA in the epidermis and dermis at the wound margins, expression of TGF-beta 2- or TGF-beta 3-mRNA was not detected. Biopsies taken 24 hours following injury revealed a focally clustered distribution of TGF-beta 1 hybridisation signals in the dermis, the number of positive cells and expression levels being reduced in old mice. Topical application of all three TGF-beta isoforms enhanced TGF-beta 1 mRNA expression in the dermis of old and young mice. In biopsies taken three days following injury, TGF-beta 1 hybridisation signals were most prominent in the regenerating epidermis although at this timepoint differences in expression levels between treated and non-treated animals were less pronounced.

Animals↗
PubMed1993

[Ficus benjamina, a perennial inhalation allergen of increasing importance].

12 patients are described with perennial allergic rhinoconjunctivitis or asthma, 3 had additionally urticarial eruptions and one edema of the eyelids. In all of them sensitization to Ficus benjamina was identified by skin prick tests, in 7 cases by the additional presence of specific IgE in vitro, and in 2 it was verified by a conjunctival provocation test. 10 patients were atopic with sensitization to other respiratory allergens such as pollen, house dust mite or animal dander. 2 patients, however, with a massive exposure to Ficus benjamina at home, were non-atopic with monovalent sensitization to this plant. Ficus benjamina is a tropical tree of the genus Ficus which belongs to the Moraceae family. The allergen is located in the plant sap, the so called latex, which after evaporation binds to dust particles on the leaf surface. Upon contact they are emanated from the leaves, thus imitating allergy to house dust components. Since Ficus benjamina is a very popular decorative plant, an increasing number of sensitized individuals is to be expected. The identification of a preventable respiratory allergen is of considerable importance for the patients.

Adolescent↗
PubMed1993

TGF-beta s and TGF-beta type II receptor in human epidermis: differential expression in acute and chronic skin wounds.

Exogenously applied transforming growth factor-beta (TGF-beta) isoforms enhance wound healing processes in animal models; however, little is known about the expression of endogenous TGF-beta s and TGF-beta receptors in intact human skin or during wound healing. The present study has revealed several unexpected findings by means of in situ hybridization and immunohistology techniques. In humans, TGF-beta 3 is constitutively expressed in the epidermis of intact skin and in that of acute and chronic wounds--a pattern of expression closely mirrored by the TGF-beta type II receptor. Although not detected in intact skin, TGF-beta 1 mRNA expression was observed in the regenerating epidermis of acute (thermal) wounds but was not found in chronic decubital (pressure) wounds. TGF-beta 2 mRNA expression was not detected in the epidermis of any human skin or wound biopsies. From these findings we suggest that constitutive expression of TGF-beta 3 is important for maintenance of epidermal differentiation and that an induction of TGF-beta 1 expression is essential for re-epithelialization of human skin wounds. Lack of TGF-beta 1 expression in chronic pressure wounds may be associated with their protracted healing tendencies.

Adult↗
PubMed1993

In situ hybridization analysis of cytokine, proto-oncogene and tumour suppressor gene expression in psoriasis.

The purpose of this study was to investigate and to compare, by in situ hybridization, gene expression of IL-1 beta, IL-8, TGF-beta 1, TGF-beta 2, TGF-beta 3, TGF-alpha, p53 and c-myc in lesions and in non-involved skin of patients with psoriasis. All lesional skin biopsies showed overexpression of IL-1 beta, IL-8 TGF-alpha mRNAs. IL-1 beta hybridization signals were strong in a small number of cells localized predominantly in the dermal papillae and in the suprapapillary epidermis. Overexpression of TGF-alpha was observed in all suprabasal keratinocytes, whereas strongly elevated IL-8 mRNA expression was found to be restricted to clusters of suprabasal keratinocytes. TGF-beta 3, p53 and c-myc transcripts were clearly detected in the epidermis of all biopsies, although expression levels were comparable in lesional and non-lesional skin.

Cytokines↗
PubMed1993

[Monitoring aortocoronary bypass. A new experimental approach].

Only few data are known concerning haemodynamic parameters and pathomechanisms of small vessels and bypass grafts. No easy-to-use bedside method exists for monitoring. We developed a miniaturised implantable Doppler probe linked to a 20 MHz pulsed Doppler system. In a circulation model and in animal studies we can show the accuracy of this method. We conclude that the implantable pulsed Doppler system is a sensitive method for monitoring the haemodynamics of small vessels.

Animals↗
PubMed1993

Severe isolated allergy to Ficus benjamina after bedroom exposure.

Allergies to Ficus benjamina (Fb, weeping fig) have been described first as an occupational disease in plant keepers and later in clearly atopic subjects with known sensitizations to other inhalant allergens. We report a case of a hitherto nonatopic man with allergic rhinoconjunctivitis, contact urticaria, and asthma caused by a Fb kept in his bedroom for 18 months. Rubbing and skin prick test with native fig leaves and sap, and RAST to Fb were clearly positive. No other sensitization could be detected. After eliminating his Fb, he became asymptomatic within a few months. This case shows that private close contact to Fb can also induce allergy even in hitherto nonatopic subjects. Therefore, Fb should not be kept in bedrooms.

Adult↗
PubMed1993

Variable and multiple expression of Protease Nexin-1 during mouse organogenesis and nervous system development.

Protease Nexin-1 (PN-1) also known as Glia-Derived Nexin (GDN) inhibits the activity of several serine proteases including thrombin, tissue (tPA)- and urokinase (uPA)-type plasminogen activators. These and other serine proteases seem to play roles in development and tissue homeostasis. To gain insight into where and when PN-1 might counteract serine protease activities in vivo, we examined its mRNA and protein expression in the mouse embryo, postnatal developing nervous system and adult tissues. These analyses revealed distinct temporal and spatial PN-1 expression patterns in developing cartilage, lung, skin, urogenital tract, and central and peripheral nervous system. In the embryonic spinal cord, PN-1 expression occurs in cells lining the neural canal that are different from the cells previously shown to express tPA. In the developing postnatal brain, PN-1 expression appears transiently in many neuronal cell populations. These findings suggest a role for PN-1 in the maturation of the central nervous system, a phase that is accompanied by the appearance of different forms of PN-1. In adults, few distinct neuronal cell populations like pyramidal cells of the layer V in the neocortex retained detectable levels of PN-1 expression. Also, mRNA and protein levels did not correspond in adult spleen and muscle tissues. The widespread and complex regulation of PN-1 expression during embryonic development and, in particular, in the early postnatal nervous system as well as in adult tissues suggests multiple roles for this serine protease inhibitor in organogenesis and tissue homeostasis.

Amyloid beta-Protein Precursor↗
PubMed1992

Thymic hyperplasia in transgenic mice caused by immortal epithelial cells expressing c-kit ligand.

To dissect mechanisms that co-ordinate specific events in thymopoiesis we have characterized alterations in thymic structure and function caused by expression of a transgene. This gene encodes SV40Tag and is specifically expressed in a subset of thymic epithelial (TE) cells around birth. As a result the number of immortal TE cells increases, thymic mass increases (up to 3 g), and thymopoiesis is expanded. The latter is reflected by a approximately 100-fold increase of the major thymocyte subsets and increased peripheral T cell counts. Grossly hyperplastic thymi retain many but not all morphological features of a normal thymus. Also in grafts, SV40Tag+ TE cells steer expansion (up to 8 g) and organize a tissue with mainly cortex-like features that includes mainly SV40Tag+ TE cells, thymocytes, and macrophages. To investigate expression of specialized gene functions in the immortal TE cells, a cell line was derived. The Epi-A1 cell line expresses the genes for major histocompatibility complex class I and II, Thy-1, interleukin (IL)-6, IL-7, macrophage-colony-stimulating factor, and transforming growth factor-beta 3. Most importantly, Epi-A1 cells also express the IL-4 receptor and the c-kit ligand (KL), a factor that, in concert with commitment factors, channels progenitors into hemopoietic lineages. The expression of low constitutive levels of KL mRNA does not require IL-4, but KL mRNA levels are increased dramatically in response to IL-4. Since constitutive expression of KL mRNA in vivo is restricted to a small subset of TE cells in the thymus, our findings reveal a novel specific interaction between thymocytes and a specialized subset of TE cells.

Age Factors↗
PubMed1992

Stimulatory and inhibitory effects of galanin on exocrine and endocrine rat pancreas.

The influence of the neuropeptide galanin, present in intrapancreatic nerve endings, on the endocrine pancreas is well known. The most potent effect of galanin is inhibition of insulin release. Little is known of its effect on the exocrine pancreas. Whether galanin plays a role in the regulation of exocrine pancreatic secretion and whether this effect is mediated directly on acinar cells or indirectly via the influence on insulin secretion is not clear. In the present study, we investigated these questions using the model of the isolated and arterially perfused rat pancreas with intact exocrine and endocrine secretion. In the presence of 15.8 mM glucose in a modified Krebs-Ringer buffer and during half-maximal stimulation of enzyme secretion with 100 pmol/ml cholecystokinin octapeptide (CCK-8), a dose-response study of 0.001-100 pmol/ml porcine galanin was performed. At concentrations of 0.001 and 0.01 pmol/ml, porcine galanin significantly stimulated insulin release (p < 0.05 and < 0.01, respectively) and also significantly enhanced CCK-8-stimulated amylase secretion (p < 0.05). Doses of 0.1 and 1 pmol/ml galanin resulted in a nonsignificant inhibition of insulin release, while 10 and 100 pmol/ml strongly inhibited the endocrine response (p < 0.001). However, concentration levels of 1-100 pmol/ml galanin did not affect CCK-8-stimulated amylase secretion. Rat galanin, tested at 0.01 and 10 pmol/ml, showed no significant difference from the effects of porcine galanin at the equipotent concentrations. It is concluded that the effect of galanin on exocrine pancreas, like the effect on endocrine functions, tends to be a direct one and that it could exert a modulatory influence on the level of neuronal transmission.

Amylases↗