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Biomedical subjects

M Blom

Publications and source records attributed to M Blom.

At least 37 records · Page 2Linked to original sources
PubMed1998

The influence of sensory stimulation (acupuncture) on the release of neuropeptides in the saliva of healthy subjects.

In recent studies we have shown that xerostomia (dry mouth) can be treated successfully with sensory stimulation (acupuncture). The increase of saliva secretion lasted often for at least one year. Some neuropeptides have been found to influence the secretion of saliva. The aim of this study was to investigate the mechanisms behind the effect of acupuncture on salivary secretion by measuring the release of neuropeptides in saliva under the influence of sensory stimulation. VIP-like immunoreactivity (VIP-LI), NPY-LI, SP-LI, CGRP-LI and NKA-LI were analysed in the saliva of eight healthy subjects. Manual acupuncture and acupuncture with low-frequency electrical stimulation (2 Hz) were used. The saliva was collected during 20 minutes before the start of acupuncture stimulation, then during 20 minutes while the needles were in situ and then for another 20 minutes after the needles were removed. Four different saliva sampling techniques were used: whole resting saliva, whole saliva stimulated by paraffin-chewing, whole saliva stimulated by citric acid (1%), and parotid saliva, also stimulated with citric acid (1%). The results showed significant increases in the release of CGRP, NPY and VIP both during and after acupuncture stimulation, especially in connection with electro-acupuncture. SP showed only few increases, mainly in connection with electro-acupuncture, whereas NKA generally was unaffected by the acupuncture stimulation. The sensory stimulation-induced increase in the release of CGRP, NPY and VIP in the saliva could be an indication of their role in the improvement of salivary flow rates in xerostomic patients who had been treated with acupuncture.

Acupuncture Therapy↗
PubMed1998

Sensory stimulation (acupuncture) increases the release of vasoactive intestinal polypeptide in the saliva of xerostomia sufferers.

We have shown in earlier studies that xerostomia can be treated successfully with acupuncture. We also found that acupuncture stimulation can increase the concentration of neuropeptides in the saliva of healthy subjects. In this study, the concentration of the neuropeptide vasoactive intestinal polypeptide (VIP) was measured in the saliva of xerostomic patients in connection with acupuncture treatment (AP). Patients suffering from xerostomia caused by irradiation treatment, Sjögren's syndrome and other systemic disorders had been treated with acupuncture. Some of these patients showed an increase of their salivary flow rates after the AP was completed. Seventeen patients out of 65 were chosen due to their ability to produce enough saliva for the radio immunoassay (RIA) analyses to be conducted prior to the start of AP. VIP-like immunoreactivity (VIP-LI) was measured in the chewing stimulated saliva of these patients before and after the whole AP (24 sessions of 30 min each). The results showed that there was a significant increase of the concentration of VIP after the AP as compared to the measurements made before the start of the treatment (p<0.05). We concluded that the increase of neuropeptide VIP might be one of the mechanisms behind the positive effect of acupuncture on the salivary flow rates of the xerostomic patients.

Acupuncture Therapy↗
PubMed1998

Orally fed digalactosyldiacylglycerol is degraded during absorption in intact and lymphatic duct cannulated rats.

Membrane lipids of green plants digalactosyldiacylglycerol (DGalDG) and monogalactosyldiacylglycerol (MGalDG) are hydrolyzed in vitro by human duodenal contents, pancreatic juice and bile salt stimulated lipase and guinea pig and rat pancreatic lipase-related protein 2 to free fatty acids, di- and monogalactosylmonoacylglycerols and water soluble galactose-containing compounds. The fate of intermediate products is unknown. We have investigated the digestion and absorption of DGalDG in rats. [3H]- and [14C]-labeled DGalDG in galactolipid dispersions, and 200 g/L soybean triacylglycerol (TG) oil-galactolipid emulsions of different concentrations were fed orally to intact and lymphatic duct cannulated rats. Chyle, gastrointestinal tract, liver and plasma were analyzed for radioactivity in different lipid classes. Recovery of [3H] also was determined in feces. Comparison was made with an emulsion of [14C]dipalmitoyl-phosphatidylcholine ([14C]DPPC), soybean TG oil and soybean phosphatidylcholine (PC). Less than 2% of the radioactivity in chyle was found in DGalDG, >70% of the radioactivity in triacylglycerol (TG), and the remaining part in glycerophospholipids. In intact rats, <1.5% of radioactivity in liver and plasma was identified as DGalDG. In experiments where 120 mg galactolipid-phospholipid mixture or 120 mg PC were given in a soybean TG oil-emulsion, the absorption of galactolipid fatty acids was less complete than PC-fatty acids, as indicated by analysis of feces and intestinal contents. Galactolipids are not absorbed intact or as reacylated monoacyl compounds by rats.

Administration, Oral↗
PubMed1998

Eosinophil granulocyte interaction with serum-opsonized particles: binding and degranulation are enhanced by tumor necrosis factor alpha.

Eosinophils participate in the inflammatory response seen in allergy and helminthic infestation. Their release of granule-bound cationic proteins may play a role in these diseases. Therefore, we investigated mechanisms involved in the release of eosinophil cationic protein (ECP). Serum-opsonized zymosan was phagocytosed by eosinophils, and ECP was released into the phagosomes as judged by immunoelectron microscopy. Degranulation to the external milieu was induced by serum-opsonized, non-phagocytosable Sephadex beads (SOS), and ECP release was determined by use of an enzyme-linked immunosorbent assay. CD11b, CD18, and CD32 monoclonal antibodies inhibited degranulation, demonstrating dependence on complement receptor type 3 (CR3), and the low-affinity Fc receptor for IgG. Tumor necrosis factor-alpha (TNF-alpha) and interleukin (IL)-5 both rapidly enhanced the binding of eosinophils to serum-opsonized zymosan, and also the release of ECP upon interaction with SOS. The cytokine-induced increase in ECP release was inhibited by the phospholipase A2 (PLA2) inhibitor mepacrine, indicating an involvement of PLA2 in the enhanced response but not in baseline degranulation. Autocrine stimulation by the platelet-activating factor (PAF) is unlikely since the PAF receptor antagonist WEB 2086 did not inhibit the enhanced response. In conclusion, the main signals for eosinophil degranulation on serum-opsonized particles are mediated by CR3 and receptors for immunoglobulins. As for IL-5, TNF-alpha changes eosinophil phenotype from a resting to an activated state.

Antibodies, Monoclonal↗
PubMed1997

Neuropeptides in the saliva of healthy subjects.

Five neuropeptides: Substance P (SP), Neurokinin A (NKA), Calcitonin Gene-Related Peptide (CGRP), Neuropeptide Y (NPY) and Vasoactive Intestinal Polypeptide (VIP), were measured in the saliva of eight subjects. The saliva was collected using different stimulation techniques: whole resting saliva, whole paraffin stimulated saliva, whole citric acid stimulated saliva and parotid saliva of different secretion rates -0.25 mL/min, 0.50 mL/min and 1.00 mL/min, also stimulated by citric acid. The neuropeptides were analysed by radioimmunoassay. The results showed that the concentration of all neuropeptides decreased significantly, two- to four-fold (CGRP up to 16-fold) in whole saliva, when the salivary secretion rates increased six- to eight-fold due to stimulation. However, the amounts of all neuropeptides released over time into the whole saliva increased two- to five-fold (ten-fold for CGRP) as the volumes of saliva increased due to chewing-stimulation as compared to resting saliva or citric acid stimulated saliva. There was also more CGRP in the resting saliva than in the citric acid stimulated saliva. The concentration of CGRP in the parotid saliva decreased three- to ten-fold when the salivary flow increased, whereas the concentration of NKA increased three- to four-fold and that of NPY almost two-fold under the same conditions. The concentrations of SP and VIP did not change in the different flows of parotid saliva. The release of all neuropeptides in the parotid saliva over time showed significant increases (3-14-fold) when the secretion rates increased except CGRP, which showed no changes at all. We concluded that neuropeptides are continuously released into the saliva. Their amounts increase with stimulation, but they are diluted by the increased volume of saliva, and they are also affected by the mode of stimulation-muscular activity leads to a greater release than citric acid stimulation. As the neuropeptides play an important role in the control of salivary secretory mechanisms, their normal occurrence and release are of fundamental importance for the understanding of the function of the salivary glands.

Adult↗
PubMed1997

The influence of acupuncture on salivary flow rates in healthy subjects.

This study investigated the influence of acupuncture stimulation on the salivary secretion of eight healthy subjects. The salivary flow of each subject was measured before, during and after every acupuncture session. The unstimulated, chewing-stimulated and citric acid-stimulated flows were investigated, in combination with manual and electrically stimulated acupuncture. The results showed a significant increase of the unstimulated salivary flow both during and after the manual acupuncture stimulation as compared to baseline levels. There was no effect on the unstimulated salivary flow with electro-acupuncture. The stimulated salivary flow was not affected by manual acupuncture, while the electrically stimulated acupuncture led to a significant decrease of the chewing-stimulated salivary flow. The improvement of the unstimulated salivary secretion in healthy subjects was in accordance with our previous findings in xerostomic patients. It is possible that the salivary secretion is influenced by the augmented release of neuropeptides caused by acupuncture. Some neuropeptides have been shown to affect salivary secretion as well as capillary blood flow.

Acupuncture Therapy↗
PubMed1996

Acupuncture treatment of patients with radiation-induced xerostomia.

Xerostomia is a common and usually irreversible side effects in patients receiving radiation therapy (> 50 Gy) for head and neck cancer. Of 38 patients with radiation-induced xerostomia, 20 in the experimental group were treated with classical acupuncture and 18 patients in the control group received superficial acupuncture as placebo. Within both groups the patients showed significantly increased salivary flow rates after the acupuncture treatment. In the experimental group 68% and in the control group 50% of the patients had increased salivary flow rates at the end of the observation period. Among those patients who had had all their salivary glands irradiated, 50% in both groups showed increased salivary flow rates (> 20%) by the end of the observation period of 1 year. The study indicates that among the patients who had increased salivary flow rates already after the first 12 acupuncture sessions, the majority had high probability of continual improvement after the completion of acupuncture treatment. The improved salivary flow rates usually persisted during the observation year. The changes observed in the control group were somewhat smaller and appeared after a longer latency phase. Significant differences for salivary flow rates could be observed only within each group, and there were no statistically significant differences between the groups. There were no differences in the improvement of salivary flow rates between those patients who were irradiated within a year before the acupuncture treatment and those who had received radiation therapy several years earlier. The results indicate that acupuncture might be a useful method for the treatment of radiation-induced xerostomia, and that superficial acupuncture should preferably not be used as placebo acupuncture.

Acupuncture Therapy↗
PubMed1995

[Ryegrass cramps in horses].

CASE STUDY: To elaborate the diagnosis of rye-grass intoxication in a stallion demonstrating a neurotoxic syndrome characterized by ataxia and incoordination, a number of diagnostic tests were performed. Results of both, blood chemistry and haematology gave no indication for organ-specific or systemic lesions. Chemical analysis of the hay fed to the horse revealed the presence of the mycotoxin lolitrem B in concentrations consistent with those described in sheep and cattle with similar symptoms. Thus, it was concluded that the animals demonstrated the rye-grass-stagger(RGS)-syndrome.

Animals↗
PubMed1995

Eosinophils isolated with two different methods show different characteristics of activation.

Eosinophils can be isolated from a mixed suspension of granulocytes by different procedures. We compared functional responses of human eosinophils purified according to two different principles: (1) an fMLP-induced difference in specific gravity between eosinophils and neutrophils and (2) selective removal of neutrophils by means of immunomagnetic beads coated with CD16 mAb. The results showed that eosinophils isolated with the CD16 beads method have a higher capacity to synthesize platelet activating factor (PAF) after stimulation with serum-treated zymosan (STZ) than eosinophils purified with the fMLP method. Binding of STZ and subsequent activation of the respiratory burst were also increased in CD16-isolated eosinophils. Furthermore, eosinophils isolated with the CD16 beads showed stronger chemotactic responses towards C5a and PAF. The difference in activity of these eosinophil preparations might be explained by a loss of the more active cells during the isolation with the fMLP method: only 30-60% of the eosinophils were recovered with this method, in contrast to a recovery of more than 95% with the CD16 beads method. Indeed, this 'lost' population of eosinophils, subsequently purified with CD16-coated beads, had a higher respiratory burst activity. The alternative explanation, i.e., an enhancement of eosinophil function by the beads method, appeared not to be valid, because repurification of fMLP-isolated eosinophils in the presence of fresh neutrophils and CD16-coated beads did not change the reactivity of the eosinophils. We conclude that the fMLP method leads to selective purification of eosinophils with a resting (or 'unprimed') phenotype.

Antigens, CD↗
PubMed1994

Granulocyte-macrophage colony-stimulating factor, interleukin-3 (IL-3), and IL-5 greatly enhance the interaction of human eosinophils with opsonized particles by changing the affinity of complement receptor type 3.

Eosinophil functions can be modulated by several cytokines such as granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), and IL-5. We have investigated the modulatory role of these cytokines on the interaction of human eosinophils with opsonized particles (serum-treated zymosan [STZ]). Addition of STZ to eosinophils isolated from the peripheral blood of normal human donors resulted in an interaction of the STZ particles with only 15% to 25% of the cells. Treatment of the eosinophils with GM-CSF, IL-3, or IL-5 strongly enhanced both the rate of particle binding and the percentage of eosinophils binding STZ. The effect of the cytokines is most likely mediated by a change in affinity of the complement receptor type 3 (CR3) on the eosinophils for the complement fragment iC3b on the STZ particles. This is indicated by the observation that (1) the effect of the cytokines on STZ binding was prevented by a monoclonal antibody against the iC3b-binding site on CR3 and (2) the enhanced binding was already apparent before upregulation of CR3 on the cell surface was observed. In a previous study, similar results were obtained with platelet-activating factor (PAF)-primed eosinophils. Because we found that the cytokines strongly enhanced the STZ-induced PAF synthesis, we investigated the role of both released PAF and cell-associated PAF in the priming phenomenon by the cytokines. Cytokine priming appeared to be largely independent of the synthesis of PAF.

Eosinophils↗
PubMed1993

Freezing adhesion molecules in a state of high-avidity binding blocks eosinophil migration.

Leukocyte extravasation is mediated by multiple interactions of adhesive surface structures with ligands on endothelial cells and matrix components. The functional role of beta 1 (CD29) integrins (or very late antigen [VLA] proteins) in eosinophil migration across polycarbonate filters was examined under several in vitro conditions. Eosinophil migration induced by the chemoattractant C5a or platelet-activating factor was fully inhibited by monoclonal antibody (mAb) 8A2, a recently characterized "activating" CD29 mAb. However, inhibition by mAb 8A2 was observed only under filter conditions that best reflected the in vivo situation, i.e., when the eosinophils migrated over filters preincubated with the extracellular matrix (ECM) protein fibronectin (FN), or when the filters were covered with confluent monolayers of cultured human umbilical vein endothelial cells (HUVEC). When bare untreated filters were used, mAb 8A2 had no effect, whereas the C5a-directed movement was prevented by CD18 mAb. Studies with alpha-subunit (CD49)-specific mAbs indicated that the integrins VLA-4 and -5 mediated migration across FN-preincubated filters, and VLA-2, -4, -5, and -6 were involved in eosinophil migration through filters covered with HUVEC. In contrast with the activating CD29 mAb 8A2, a combination of blocking CD49 mAbs or the nonactivating but blocking CD29 mAb AIIB2 failed to inhibit completely eosinophil migration over FN-preincubated or HUVEC-covered filters. mAb 8A2 stimulated binding to FN but not to HUVEC. Moreover, eosinophil migration over FN-preincubated or HUVEC-covered filters was significantly inhibited by anti-connecting segment 1 (CS-1) mAbs, as well as the soluble CS-1 peptide (unlike migration across bare untreated filters). Thus, inhibition of eosinophil migration by mAb 8A2 depended upon the presence of ECM proteins and not upon the presence of HUVEC per se. In conclusion, "freezing" adhesion receptors of the beta 1 integrin family into their high-avidity binding state by the activating CD29 mAb 8A2 results in a complete inhibition of eosinophil migration under physiological conditions. Hence, activation of beta 1 integrin-mediated cell adhesion may represent a new approach to prevent influx of inflammatory cells.

Antibodies, Monoclonal↗
PubMed1993

Transient exposure of human eosinophils to the protein kinase C inhibitors CGP39-360, CGP41-251, and CGP44-800 leads to priming of the respiratory burst induced by opsonized particles.

We report that a transient incubation of human eosinophils with the protein kinase C (PKC) inhibitor CGP39-360 (staurosporine) or the more PKC-specific inhibitors CGP41-251 and CGP44-800 prior to activation of the respiratory burst with opsonized particles results in priming of this response. This priming effect was concentration dependent and occurred in the range in which the phorbol myristate acetate-induced respiratory burst was inhibited. CGP39-360 priming was minimally affected in Ca(2+)-depleted cells, indicating that an increase in [Ca2+]i is not important. Also, the binding of serum-treated zymosan (STZ) particles was strongly enhanced by the inhibitors. On the other hand, the release of platelet-activating factor (PAF) induced by opsonized particles was enhanced only by CGP39-360 and not by CGP41-251 and CGP44-800. Therefore, priming of the respiratory burst is not due to an aspecific enhancing effect of the inhibitors. These data indicate that different signal transduction routes are involved in priming of the STZ-induced respiratory burst and PAF release in human eosinophils.

Alkaloids↗
PubMed1993

Effects of diclofenac on isradipine pharmacokinetics and platelet aggregation in volunteers.

In this open, two-period crossover study in 18 healthy male volunteers, a single oral dose of 50 mg diclofenac was administered alone and on day 7 of multiple oral dosing of 5 mg b.i.d. isradipine to assess a possible pharmacokinetic interaction. The effect of these drugs on ex vivo platelet function was also determined. Serial blood samples were obtained over 12-hour periods on three occasions: after the single diclofenac dose; after the morning dose of isradipine on day 6 and after co-administration of both drugs on day 7 of steady-state isradipine administration. Additional samples were taken at 2 h post dose for determination of ex vivo platelet aggregation. Isradipine plasma concentrations were determined by a gas chromatographic method and diclofenac plasma concentrations by an HPLC method. The pharmacokinetic characteristics of diclofenac were unaltered during co-administration. The maximum plasma concentration of isradipine was increased 19.6% during co-administration from 5.06 to 6.05 ng.ml-1. This is not expected to be of clinical importance. Isradipine's apparent total body clearance and steady-state AUC remained unchanged. Ex vivo induced platelet aggregation was not affected by any of the treatments.

Adult↗
PubMed1993

Effects on local blood flux of acupuncture stimulation used to treat xerostomia in patients suffering from Sjögren's syndrome.

Twenty-one patients with Sjögren's syndrome were given four different kinds of acupuncture stimulation, at acupuncture points previously used to treat xerostomia. The local blood flux in the skin overlying the parotid gland was measured with laser Doppler flowmetry before, during and after the acupuncture stimulation. The results showed that the local blood flux increased significantly during and after both manual acupuncture and low-frequency (2 Hz) electro-acupuncture as compared with superficial acupuncture. These results indicate that acupuncture induced an increase in the local blood flux which was more pronounced for those patients who had previously reacted with increased salivary flow to acupuncture.

Acupuncture Therapy↗
PubMed1993

Appropriate sera for calibration and control of specific protein assays.

An ultracentrifugation technique is described which makes it possible to prepare protein calibrators and control sera which (i) are stable (more than 8 years documented for nine proteins), (ii) are clear (remains clear for more than 8 years at -80 degrees C), (iii) contain genuine proteins (documented electrophoretically and immunologically), and (iv) are reproducible to prepare (collection and preparation).

Blood↗