Fusion of the envelope of mucous droplets with the luminal plasma membrane in acinar cells of the cat submandibular gland.

The release of mucus from acinar cells of the cat submandibular gland was examined by electron microscopy. The limiting membrane of mucous droplets fuses with the luminal plasma membrane to form a five-layered contact. This is converted to a three-layered membrane (unit membrane) by avulsion of the plasmalemma. Attenuation and rupture of this membranous barrier permits the contents of the mucous droplets to flow into the lumen.

Effect of flunarizine and calcium on serotonin uptake in human and rat blood platelets and rat synaptosomes.

Calcium and the calcium overload blocker flunarizine exert profound effects on mood. We therefore studied the effect of calcium and flunarizine on serotonin uptake in human and rat blood platelets and in rat synaptosomes. Calcium (1.3 mmol/L) had a weak inhibiting effect on serotonin uptake in blood platelets, whereas no effect was observed in synaptosomes. Flunarizine inhibited serotonin uptake in a concentration dependent manner with an IC50 value of 1 mumol/L in blood platelets and 5 mumol/L in synaptosomes. The inhibition did not depend on the presence of extracellular calcium indicating that the effect is not coupled to a blockade of cellular calcium influx. In human blood platelets, the inhibition was of the noncompetitive type. These results indicate that flunarizine interacts directly with the 5-HT uptake site. The relatively high concentration of flunarizine required to inhibit 5-HT uptake may question the clinical importance of this effect.

Peptide-evoked release of amylase from isolated acini of the rat parotid gland.

Investigations of the effects of the neuropeptides, substance P (SP), neurokinin A (NKA), neuropeptide K (NPK), gastrin releasing peptide (GRP), calcitonin gene related peptide (CGRP) and vasoactive intestinal peptide (VIP), and of acetylcholine on amylase secretion have been carried out on isolated acini of the rat parotid gland. Furthermore, the occurrence and location of the peptides in the gland was studied. Finally, binding of 125I-BH-SP to isolated acini were studied in order to characterize their tachykinin receptor(s) and their binding kinetics. Only SP, NKA, NPK and VIP stimulated amylase release. VIP, however, with a rather low potency (EC50 at 155 nmol/l). Simultaneous stimulation with two compounds elicited additive responses, except for VIP and acetylcholine which elicited an effect significantly above additive response. Only SP, NKA, VIP and CGRP could be identified in extracts of the gland. The immunoreactivity of these peptides could be located to varicose nerve fibers in the gland. Binding of labeled SP to the isolated acini exhibited the characteristics of a genuine agonist/receptor interaction, and the rank order of displacement potencies indicated the presence of NK1-receptors. Thus, the results of the present study support previous suggestions that the tachykinins and VIP are likely to be involved in amylase secretion in the rat parotid gland.

Familial progressive myoclonic epilepsy. A clinical, genetical, biochemical and patho-anatomical study of a family with a 6-year follow-up.

Six siblings, including 4 cases of myoclonic epilepsy, their parents and 2 grandmothers were subjected to systematic investigation, and the patients were followed-up. The genetic studies revealed in the mother's family a patient with Lafora bodies demonstrated at autopsy. No chromosome abnormalities were found nor any linkage to the HLA system. The affected family members were characterized biochemically by an increased excretion of total glycosaminoglycans and/or an abnormal electrophoretic pattern of urinary glycosaminoglycans with an increased proportion of low-sulfated glycosaminoglycans. In the healthy family members this pattern of electrophoresis could also be demonstrated in the father and the paternal grandmother. Based on the biochemical results and the genetic studies it is suggested that the family members with progressive familial myoclonic epilepsy present a combination of at least 2 hereditary defects. The course of the disease has been relatively benign and treatment with sodium valproate, baclofen and clonazepam has shown quite satisfying results. In consequence of the biochemical findings combined treatment with A and E vitamins has been initiated.

Dermal glycosaminoglycans characterise the primary irritant dermatitis in psoriatics and healthy individuals.

Primary irritant dermatitis includes an inflammatory process of connective tissue which is of general interest. For the first time this process has been characterised biochemically in humans by following the dermal changes in the concentration of hydroxyproline and four glycosaminoglycans. In healthy individuals (n = 7) and in psoriatics (n = 8) the changes were rather similar. Only dermatan sulphate showed a tendency towards an abnormal response in the psoriatics. In both groups the deviations from the pre-irritant condition clearly distinguished the response of irritant dermatitis from that of the wound healing process: (1) the concentration of hyaluronic acid decreased by the third day and remained so until by the sixth day, (2) after a decrease on the third day the concentration of dermatan sulphate returned to the initial value by the sixth day, (3 and 4) the concentration of chondroitin 4/6-sulphate and heparan sulphate increased continuously from the third to the sixth day, and (5) the concentration of hydroxyproline remained constant throughout the period of investigation.

Dermatan sulphate in urine reflects the extent of skin affection in psoriasis.

The investigation included 15 psoriatic patients and 14 healthy controls. By using a simple method based on susceptibility to chondroitinases the excretion of dermatan sulphate, chondroitin-4/6-sulphate and heparan sulphate in the psoriatics was found to be increased with 104, 62 and 47% from uronic acid mean excretions of 1.97, 6.37 and 5.10 mumol/24 h, respectively. The excretion of hydroxyproline was not increased. In both groups the excretion of hyaluronic acid was insignificant. The absolute increase in the excretion of a major skin component like dermatan sulphate was exceeded by the excretion of chondroitin-4/6-sulphate and heparan sulphate which are both small components of skin. This indicates a comparatively high turnover of those two fractions in psoriatic lesions. The fact, that only the excretion of dermatan sulphate correlated with the fraction of skin surface involved in the psoriatic disease, indicated an important origin of this fraction, as well as the possibility of dermatan sulphate as a means of following dermal metabolism.

ELISA for the core protein of the cartilage large aggregating proteoglycan, aggrecan: comparison with the concentrations of immunogenic keratan sulphate in synovial fluid, serum and urine.

Immunological assays for fragments of the cartilage large aggregating proteoglycan, aggrecan, have been widely used to monitor cartilage turnover. These assays have commonly employed the monoclonal keratan sulphate antibody, 5D4. Keratan sulphate, however, is present in many tissues and 5D4 affinity is critically dependent on antigen structure. We have therefore raised and characterized a monoclonal antibody (1-F21) that reacts with the core protein of aggrecan without interference from the glycosaminoglycan side chains and, using this antibody, we have optimized a sensitive, competitive ELISA. The within-assay and between-assay coefficients of variation were 4.9-8.9% and 11.1-13.0%, respectively. The mean concentrations of core protein in synovial fluid, serum and urine were 76.4 micrograms/ml, 104.0 ng/ml and 81.0 ng/ml, respectively. In synovial fluids the concentrations were closely correlated with the concentrations of keratan sulphate as determined by 5D4 (r = 0.94), whereas in serum and urine there was no obvious correlation between the determinations. These findings show that measurement of both core protein and keratan sulphate results in a more precise description of aggrecan turnover.

Demonstration of immunogenic keratan sulphate in commercial chondroitin 6-sulphate from shark cartilage. Implications for ELISA assays.

The prototype monoclonal keratan sulphate (KS) antibody 5D4 that is widely used for detection of KS in tissues and biological fluids reacts strongly with commercial low grade shark cartilage chondroitin 6-sulphate. Characterization of the immunogenic material by chondroitinase ABC digestion, ELISA inhibition studies, immunoblotting and HPLC analyses confirmed the presence of substantial amounts of KS, probably as a large proteoglycan (> 120 kDa). Commercial and heterogenic glycosaminoglycan preparations therefore must be used with great caution in immunological analyses. On the other hand the shark cartilage chondroitin 6-sulphate is an easy accessible source of immunogenic KS that can be used as a reference standard and as coating antigen in KS-ELISAs. The concentration of immunogenic KS in synovial fluid measured with an ELISA based solely on reagents of shark cartilage chondroitin 6-sulphate correlated well (r = 0.90) with the concentrations obtained with a traditional KS-ELISA that uses purified aggrecan as standard and coating antigen, and KS in both serum and synovial fluid could be measured with sufficient linearity.

A new quantitative RT-PCR assay for thymidylate synthase mRNA in blood leukocytes applied to cancer patients and healthy controls.

Thymidylate synthase (TS) is the target enzyme for 5-fluorouracil (5-FU). TS mRNA and protein levels in colorectal tumours are among the most important determinants for tumour response to 5-FU. TS mRNA levels in blood leukocytes may give information on pharmacokinetic and pharmacodynamic actions of 5-FU on TS as it has previously been shown that inhibition of TS levels by 5-FU in bone marrow leukocytes resembles the degree of TS inhibition in colorectal tumours. The aim of this study was to develop a quantitative high-throughput RT-PCR assay for TS mRNA expression in blood leukocytes (CURT-PCR). Furthermore the TS mRNA levels in blood of patients with colorectal cancer and healthy controls was compared. TS mRNA levels in 17 patients with colorectal cancer did not differ from 20 matched controls whereas a group of 14 younger controls had significantly lower TS mRNA expression than patients and matched controls. In order to investigate the sensitivity of the assay towards cellular reactions such as proliferative stimuli, isolated blood leukocytes were stimulated with phytohemagglutinin both in mitogenic and non-mitogenic concentrations and an induction of TS mRNA expression was measured in both cases. TS activity and cellular proliferation also increased but only at mitogenic concentrations, suggesting that TS mRNA expression is an early leukocyte activation marker. This new CURT-PCR assay may allow improved studies of functional kinetics of drugs with impact upon TS. Further studies are required to establish the possible clinical benefit of TS mRNA measurements in blood leukocytes.

The effects of low-dose methotrexate on thymidylate synthetase activity in human peripheral blood mononuclear cells.

OBJECTIVE: Methotrexate (MTX) in low doses is widely used in the treatment of rheumatoid arthritis (RA) and it is not known whether its effects are due to immunosuppressive and/or anti-inflammatory actions. High concentrations of MTX inhibit the activity of thymidylate synthetase (TS) and dihydrofolate reductase essential for DNA synthesis. This study investigated the effects of low-dose MTX on TS activity and proliferation in human peripheral blood mononuclear cells (PBMC). METHODS: The MTX concentrations in our experiments were chosen according to the plasma concentrations measured in 8 RA patients treated with MTX. The effect of MTX on TS activity and DNA synthesis were measured in stimulated normal PBMC and in PBMC obtained from 6 RA patients treated with oral MTX before and 2 hours after intake of their weekly MTX dose. The effect of MTX on the TS mRNA concentration was also investigated in order to elucidate its effect on TS production. RESULTS: Low-dose MTX significantly inhibited TS activity and the proliferation of stimulated PBMC independent of the mode of activation. Interestingly, the concentration of TS mRNA in normal PBMC was upregulated by the presence of MTX. Finally, there was no difference between TS activity measured before and after MTX intake in 6 RA patients on long-term MTX treatment. CONCLUSION: We show that low concentrations of MTX inhibit TS activity in vitro. An in vivo effect cannot, however, be proven given our study design. The role of these in vitro findings is discussed, particularly in relation to the in vivo effects of MTX.

The ability of hypoxia to modify the gene expression of thymidylate synthase in tumour cells in vivo.

PURPOSE: Hypoxic cells in tumours are resistant to 5-fluorouracil (5-FU). This in vivo study investigated the ability of hypoxia to regulate the gene expression of thymidylate synthase (TS), the target enzyme of 5-FU. MATERIALS AND METHODS: C3H mammary carcinomas, grown in the feet of female CDF1 mice, were used for all experiments. Mice were placed in a 10% oxygen environment for various time periods and the tumour oxygen status was determined with an Eppendorf oxygen electrode. The animals were then injected with BrdU (100 mg/kg, i.p.). Tumours were excised and immediately frozen (-80 degrees C) until isolation of total RNA. The mRNA was reversibly transcribed to complementary DNA and the resulting cDNA amplified in a multiplex PCR reaction, with beta-actin as the internal reference gene. RESULTS: One hour of low oxygen breathing made tumours significantly more hypoxic. This increase was maintained for a maximum incubation period of 48 h. In the same tumours, no change in TS gene expression was seen with up to 3 h of low oxygen breathing. At longer times it decreased, reaching significance at 12-24 h and remaining at this lower level for up to 48 h. BrdU labelling was significantly reduced after breathing low O2 for 24 h (p = 0.001). CONCLUSION: Hypoxia-induced down-regulation of TS gene expression was observed. This would be expected to make hypoxic tumour cells more sensitive to 5-FU. Other mechanisms must be responsible for the previously reported resistance to this drug.

Ultrastructure of the main excretory duct of the cat submandibular gland.

The main excretory ducts (MED's) from the submandibular gland of adult cats were examined by electron microscopy. The ducts consisted of a pseudostratified epithelial lining surrounded by abundant connective tissue and numerous, small, longitudinally-oriented blood vessels. The taller epithelial cells were closely coherent, without the luminal clefts between adjacent cells that are characteristic of rat MED's. In the cat, these cells lacked basal membrane specialization, but showed considerable lateral interdigitation. Some microvilli were present on the apical surface. In a few rare cells, the luminal surface bore cilia of typical appearance. The smaller, pyramidal basal cells had irregular basal surfaces that gave rise to one or more long cytoplasmic processes. The basal surface of the pyramidal cells was studded with hemidesmosomes. The cytoplasms contained abundant tonofilaments, which sometimes aggregated in prominent perinuclear bundles. Occasional goblet cells were present in the duct wall. MED's perfused either in situ or in a perfusion chamber with Locke's solution also were studied. Even after perfusion of 160 minutes duration, the ultrastructure of the ductal epithelium showed remarkably few alterations. The MED model system thus remains stable long enough to carry out physiological experiments which may produce ultrastructural alterations.

Comparison of the pharmacokinetics of tacrolimus and cyclosporine at equivalent molecular doses.

Even though calcineurin inhibitors, namely Tacrolimus (FK) and Cyclosporine (CsA) share similar physicochemical properties and a common mechanism of action, their pharmacokinetics (pk) are different and unpredictable. Both drugs are metabolized by cytochrome P450-3A4 isoforms in the liver and in the mucosa of the upper gastrointestinal tract. FK in clinical practice is given in doses up to 50-fold lower than those of CsA due to its greater potency. It is often assumed that the diverse dosing contributes to the observed pharmacokinetic differences between the two drugs. The objective of the present study was to compare single-dose pk profiles of the two drugs, following oral and intravenous administration, on the basis of equivalent molecular dosing, thus ruling out the quantitative factor. Five healthy volunteers and 14 dialysis patients (7 hemodialysis, 7 peritoneal dialysis) were included in the study. Comparing the pharmacokinetic parameters obtained from the drugs, it appeared that cyclosporine has an greater primary volume of distribution and clearance rate compared to tacrolimus. No other statistically significant differences were observed regarding bioavailability, absorption rate, or elimination rate. The only significant correlation between the pk values of the drugs was in primary volume of distribution. We conclude that even at equivalent molecular doses the pk of each drug remains unique and unpredictable. Furthermore our data fail to reveal significant correlations between the bioavailability, clearance, absorption, and elimination rates of the two drugs.

[The effect of serum monitoring on concentration of perphenazine and zuclopenthixole]. / Effekten af serumkontrol på koncentrationen af perfenazin og zuklopentixol.

The effect of therapeutic drug monitoring (TDM), including pharmacokinetic guidance, was examined in 994 psychiatric patients treated with perphenazine (Trilafon) or zuclopentixol (Cisordinol). Before monitoring of the serum level, half of the serum concentrations from patients given perphenazine tablets (466 patients) was below the therapeutic level, and about one third was above. For perphenazine depot (208 patients), almost no patients had a serum concentration below the therapeutic level whereas 40% had concentrations above. For zuclopentixol tablets (231 patienter) and zuclopentixol depot (163 patients), about 60% of the patients had concentrations above the therapeutic level. For all four groups, it was found that slightly more than half of the patients with serum concentrations outside the therapeutic level was reexamined. The dosage was changed in most of these patients (80-90%) in order to bring the concentration within the therapeutic level. Half of those in whom the dose was changed obtained concentrations within the therapeutic level. It is concluded that since the recommendations for changes of the dosage is followed to a wide extent, the therapeutic drug monitoring service does influence the treatment significantly.

[Long-term treatment with octreotide of patients with acromegaly]. / Medicinsk langtidsbehandling af akromegale patienter med oktreotid.

We bring our experiences with and results of octreotide treatment for 0.5 to seven years in 26 highly selected acromegalic patients, i.e. they had almost all been operated upon before or were for other reasons not first-choice neurosurgical candidates. Sixteen patients responded immediately to octreotide and achieved good control of symptoms and average serum growth hormone levels below 5 micrograms/l. Five additional patients responded adequately to octreotide after a renewed neurosurgical attempt, and two other patients achieved satisfactory control after successful neurosurgery. Thus we had to resort to radiation therapy in three out of these 26 patients. We should like to emphasize the fact that acromegalic patients, who initially do not respond adequately to octreotide therapy, may often do so after a renewed partial adenomectomy. Octreotide therapy has in our hands been practically without side effects, apart from gastrointestinal symptoms during the initial days of treatment. All 26 patients had an ultrasound-scan of the gallbladder and biliary tracts before and during long-term octreotide administration, and with the exception of one patient with gallbladder sediment, in whom no pretreatment scanning had been performed, we had no development of biliary tract abnormalities in these up to 65 year old patients. This may be due to composition and timing of meal intake in relation to that of octreotide. Fecal fat excretion, D-vitamin metabolites in serum and prothrombin time were similar in octreotide-treated and untreated acromegalic patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential effect of methotrexate on the increased CCR2 density on circulating CD4 T lymphocytes and monocytes in active chronic rheumatoid arthritis, with a down regulation only on monocytes in responders.

OBJECTIVES: To evaluate the effect of orally administered methotrexate (MTX) on the density of CC chemokine receptor 2 (CCR2) and CXC chemokine receptor 3 (CXCR3) on circulating monocytes, and the coexpression of CXCR3 and CCR2 on CD4 T lymphocytes in patients with active chronic rheumatoid arthritis. METHODS: All 34 patients with rheumatoid arthritis fulfilled the 1987 American Rheumatism Association criteria and were followed for 16 weeks after starting MTX. Peripheral blood mononuclear cells were analysed for CCR2 and CXCR3 density by three-colour flow cytometry before initiation of MTX and at week 12. RESULTS: 22 (65%) patients were non-responders, 12 (35%) patients responded to MTX by American College of Rheumatology (ACR)20% criteria, and 8 (24%) of these patients responded by ACR50%. In patients with active rheumatoid arthritis before starting MTX, CCR2 density on circulating monocytes, CD4(+) CXCR3(+) and CD4(+) CXCR3(-) T lymphocytes was increased compared with controls. During 12 weeks of MTX treatment, the CCR2 density on monocytes decreased significantly in the ACR50% group but not in the ACR20% and non-responder groups. The increased CCR2 density on CD4(+) CXCR3(+) and CD4(+) CXCR3(-) T lymphocytes was unaffected by the reduction in disease activity measured in relation to MTX treatment. The percentage of both monocytes and CD4(+) CXCR3(+) and CD4+ CXCR3(-) T lymphocytes among the peripheral circulating mononuclear cells did not change during MTX treatment. CONCLUSIONS: Active chronic rheumatoid arthritis is characterised by enhanced CCR2 density on circulating monocytes and CD4(+) CXCR3(+) and CD4(+) CXCR3(-) T lymphocytes. During MTX treatment, a decrease in CCR2 density on monocytes in the ACR50% responder group was associated with decreased disease activity. The increased CCR2 density on CD4(+) CXCR3(+) and CD4(+) CXCR3(-) T lymphocytes was uninfluenced by MTX and disease activity.

Determination of sulphate/uronic acid ratios in glycosaminoglycans separated by electrophoresis on cellulose acetate.

Glycosaminoglycans fractionated by electrophoresis on cellulose acetate strips which were stained with toluidine blue and scanned in wet condition showed optical density spectra with an absorbance maximum at 525 nm and a second maximum at 595-610 nm. The maximum at 525 nm was found to depend on the presence of sulphate groups. The maximum at 595-610 nm was present in all glycosaminoglycans investigated including hyaluronic acid and keratan sulphate. The ratio between the integrals of absorbance at 525 and 645 nm of the electrophoretic fractions showed a linear relationship with the sulphate/uronic acid ratio. This was true for a uronic acid range from 1.75 to 6.25 nmol and a sulphate/uronic acid range from 0.34 to 1.72 mol/mol. The pH value of the electrophoresis buffer and the presence of protein in the sample had no influence on the absorbance ratio. Hence preincubation with chondroitinases could be done. Keratan sulphate on the other hand could not be studied by the method because the absorbance ratio of this glycosaminoglycan was too small. In repeated determinations on urinary and dermal glycosaminoglycans the method usually resulted in coefficients of variation of 5 to 15%.