The effect of local radiotherapy on kallikrein activity in saliva secreted by parotid gland in patients with head and neck cancers

The samples of parotid gland saliva, collected from control human subjects and those taken from patients with head and neck cancers were submitted to the assay of protein concentration and kininogenase and amidolytic kallikrein activities. No patients with parotid gland tumours were included. The effect of pilocarpine stimulation on these parameters was studied. It was found that the saliva secreted by parotid gland of the investigated patients contains less protein and lower kininogenase activity in comparison to control subjects. Pilocarpine administration resulted in an increase of protein concentration and a decrease of kallikrein activity both in control and investigated subjects. Radiotherapy did not evoke any significant changes in spontaneously secreted saliva. The radiotherapy resulted in a progressive decrease of protein concentration and kallikrein activity in saliva secreted by pilocarpine stimulated glands. The kallikrein activity per mg of protein contained in spontaneously secreted saliva increased significantly during radiotherapy but it distinctly decreased in the saliva of pilocarpine-treated patients. It allows to conclude that the parotid glands do not lose their ability to synthesize and secrete kallikrein during radiotherapy of head and neck cancers.     

GLP-1 (7-36) amide: effects on glucose transport and metabolism in rat adipose tissue

In rat adipocytes, GLP-1 (7-36) amide induced an increment in 2-deoxy-glucose uptake, which was additive to that of insulin. Furthermore, in rat fat, GLP-1 (7-36) amide provoked a rise in glycogen synthesis, glucose oxidation and utilization and lipogenesis, the increments being lower than those obtained with insulin. These data support the idea that GLP-1 exerts insulin-like effects on glucose metabolism in rat adipose tissue, as it does in rat hepatocytes and skeletal muscle, although with a lower potency than that of insulin.     

Inositolphosphoglycans possibly mediate the effects of glucagon-like peptide-1(7-36)amide on rat liver and adipose tissue

Cardiac disorders are increasingly recognised as an important source of cerebral embolism. Atrial fibrillation is the most common cardiac dysrrhythmia that can predispose to stroke. Recent advances have significantly increased the identification of clinical, hematological and echocardiographic risk factors that predict the occurrence of atrial fibrillation related stroke. Also, clinical risk stratification has been used to determine medical therapy (aspirin or warfarin) for prevention of atrial fibrillation related brain embolization. Among the various structural heart diseases causing stroke, the role of patent foramen ovale remains controversial. Strides have been made in the use of ultrasonographic techniques such as transesophageal echocardiography and contrast transcranial doppler to detect patent foramen ovale. Coronary artery bypass grafting is often performed in patients with concomitant aortic atheroma and carotid stenosis that may predispose to stroke in the perioperative period. It is now possible to identify perioperatively significant aortic atherosclerosis (using transesophageal echocardiography and aortic ultrasound) and significant carotid disease (using carotid ultrasound) and make appropriate modifications in surgical technique to reduce the incidence of coronary artery bypass grafting related stroke. Because of shared risk factors it is not surprising that coronary artery disease is frequently found in stroke patients. Recent studies suggest that more than one-third of stroke patients have asymptomatic coronary artery disease. Conversely, the brain damaged by infarction may itself be responsible for the production of cardiac structural and electrical abnormalities. Both these factors may contribute to the finding that cardiac events are the leading cause of death in stroke patients on long term follow-up. Recognition of these correlations has enhanced our ability to treat and prevent stroke related mortality.     

Increased expression of intercellular adhesion molecule-1 (ICAM-1) in diabetic rat glomeruli: glomerular hyperfiltration is a potential mechanism of ICAM-1 upregulation

Mononuclear cells, including monocytes/macrophages and T-cells, are considered to be involved in the progression of diabetic nephropathy, although the mechanism of their recruitment into diabetic glomeruli is unclear. The intercellular adhesion molecule-1 (ICAM-1) promotes the infiltration of leukocytes into atherosclerotic lesions as well as inflammatory tissues. In the present study, we investigated the expression of ICAM-1 in the glomeruli of streptozotocin-induced diabetic rats. The expression of ICAM-1 was increased significantly during the early stage of diabetes. The number of mononuclear cells, primarily monocytes/macrophages and lymphocytes, was significantly increased in diabetic glomeruli. Mononuclear cell infiltration into diabetic glomeruli was prevented by anti-ICAM-1 monoclonal antibody. Insulin treatment decreased ICAM-1 expression and mononuclear cell infiltration. The ICAM-1 expression on cultured human umbilical vein endothelial cells was not induced under high glucose culture conditions. Glomerular hyperfiltration is a characteristic change in the early stage of diabetic nephropathy. Treatment with aldose reductase inhibitor, which prevented glomerular hyperfiltration without changes in blood glucose levels, decreased ICAM-1 expression and mononuclear cell infiltration. Moreover, we examined the ICAM-1 expression in the glomeruli of the 5/6 nephrectomized rat, which is a model for glomerular hyperfiltration without hyperglycemia. The ICAM-1 expression and infiltration of mononuclear cells was significantly increased in the glomeruli of 5/6 nephrectomized rats. We conclude that ICAM-1 is upregulated and promotes the recruitment of mononuclear cells in diabetic glomeruli. Moreover, glomerular hyperfiltration that occurs in the early stage of diabetic glomeruli may be one of the potential mechanisms of ICAM-1 upregulation in diabetic nephropathy.     

Subcutaneous or visceral adipose tissue expression of the PPARgamma gene is not altered in the fatty (fa/fa) Zucker rat

We cloned 537 basepairs (bp) of rat partial peroxisome proliferator-activated receptor gamma2 (PPARgamma2) cDNA and examined the effect of fasting or obesity on the expression of two isoforms of rat PPARgamma, gamma1 and gamma2, in either subcutaneous or mesenteric adipose tissue specimens using an RNase A protection assay. In Wistar rats, expression of both isoforms was dramatically reduced after 48 hours of fasting in the two fat tissue specimens. In comparing genetically obese (fa/fa) Zucker rats and lean control rats, no significant difference was observed in expression of the two isoforms in either type of adipose tissue. From these findings, we conclude that the adipose tissue level of rat PPARgamma depends on nutritional deprivation but is not closely associated with either obesity or insulin resistance in obese Zucker rats.     

Modulation of invasive potential in different clonal subpopulations of a rat rhabdomyosarcoma cell line (BA-HAN-1) by differentiation induction

Three clonal subpopulations (A, B, C) isolated from the same rhabdomyosarcoma of the rat and differing in their degree of spontaneous differentiation were tested for their invasive potential before and after differentiation induction with retinoic acid (RA), N-monomethylformamide (NMF) and sodium butyrate (NaBut). Invasive potential was analysed in an in vitro assay using embryonic chick heart fragments in organotypic culture. In standard culture medium, all three subpopulations were shown to be invasive, progressively replacing the chick heart fragments within 7-11 days after confrontation. After exposure to RA, NMF or NaBut, marked differences in the invasive potential of these subpopulations were, however, observed. Subpopulation C exhibited a pronounced decline in invasive potential, as evidenced by a significant decrease (P = 0.005) in the proportion of chick heart fragments with advanced stages of invasion. This response, however, was confined to the differentiation-inducing agents RA and NaBut, which had also produced a marked increase in morphological and/or biochemical differentiation (P = 0.0001). In contrast, NMF, which had only minor effects on differentiation, failed to affect the invasive potential of subpopulation C. In subpopulation B, a transient inhibition of single cell invasion became evident after exposure to RA, whereas NMF and NaBut failed to affect the invasive potential in spite of minor effects on differentiation. In the least differentiated subpopulation A, which was shown to be refractory to the differentiation-inducing effects of RA, NMF and NaBut, there was also no observation of any reduction of invasive potential. The results of our study demonstrate that differentiation-inducing agents can significantly reduce the invasive potential of malignant tumors, although marked differences of response are to be expected between the different subpopulations of a tumor.     

The localization of the insulin-like growth factor receptor 1 (IGFR-1) in benign and malignant breast tissue

Reactive oxygen species (ROS) are often involved in the mechanism of apoptosis. Bleomycin consists of an oxygen activating domain and a DNA binding domain, and is an antitumour agent that induces double-strand scission in DNA by oxygen activation. However, bleomycin only weakly induces apoptosis in limited conditions. Previously we have reported efficient oxygen activation by iron complexes of synthetic models of bleomycin namely PYML designed by the direct analogy to the BLM metal core. Recently, novel ligands having symmetrized coordination environment consisting of two histidine units and a pyridine (HPH) were prepared. Oxygen activating efficiency of the iron complexes of the synthetic ligands increased by introducing electron donating substituent into the pyridine ring. HPH compounds have no DNA binding region which is present in bleomycin. HPH compounds but not bleomycin induced apoptosis in mouse leukemia L1210 cells.     

The anabolic action of 17 beta-estradiol (E2) on rat trabecular bone is suppressed by (3-amino-1-hydroxypropylidene)-1-bisphosphonate (AHPrBP)

We have previously found that high doses of 17 beta-estradiol (E2), similar to those seen in late pregnancy, stimulate bone formation in adult rats. In this communication we tested the effects of a combination of E2 and (3-amino-1-hydroxypropylidene)-1,1-bisphosphonate (AHPrBP) on bone formation and bone volume in rat bone. E2 (4 mg/kg/day subcutaneously for 17 days) stimulated the bone formation rate to 6 times that of control rats. This was reduced by a single administration of AHPrBP (0.3 mg/kg subcutaneously) to 3 times control levels, and by similar daily injections of AHPrBP to levels not significantly different from those of untreated rats. Suppression of bone formation was effected predominantly through a reduction in the percentage of double-labelled surfaces, consistent with reduced osteoblast recruitment. We found only relatively minor effects of AHPrBP on the mineral apposition rate, suggesting that AHPrBP affected osteoblast function less than osteoblast recruitment. Suppression of histodynamic parameters of bone formation by AHPrBP was associated with suppression of the increase in bone volume otherwise induced by E2. The suppression by AHPrBP of the effect of E2 on bone formation contrasted with its lack of effect on other target tissues for E2, since AHPrBP did not affect the E2-induced changes in longitudinal bone growth or uterine weight. These results suggest that AHPrBP inhibits the anabolic effect of estrogen on rat trabecular bone.     

The effect of silymarin-N-methylglucamine salt and silybin-dihemisuccinate on (1-14C)-acetate incorporation in rat liver lipids (author''s transl)

60 min after i.v. application of 140.5 mg silymarin-N-methylglucamine salt/kg body weight dissolved in 4% polyvinylpyrrolidone solution, and 30 min after i.p. administration [1-14C]-acetate, compared to rats treated with solvent only, a statistically significant increase of specific radioactivities in total lipids, triglycerides, total phospholipids as well as in the phosphatidylcholine fraction and a decrease of specific activities in the free cholesterol fraction of the liver can be determined. 70 min after i.p. application of 140.5 mg silybin-dihemisuccinate/kg body weight dissolved in phosphate buffer, and 10 min after i.v. administration of [1-14C]-acetate in comparison with rats treated with solvent only, a statistically significant enhancement of specific activities of total liver lipids, free hepatic cholesterol, liver triglycerides, total liver phospholipids, and the hepatic fraction of phosphatidyl ethanolamine can be measured. Silybin also produces an increased specific radioactivity of the serum triglyceride fraction.     

Repeated intracerebroventricular administration of glucagon-like peptide-1-(7-36) amide or exendin-(9-39) alters body weight in the rat

Central nervous system glucagon-like peptide-1-(7-36) amide (GLP-1) administration has been reported to acutely reduce food intake in the rat. We here report that repeated intracerebroventricular (i.c.v.) injection of GLP-1 or the GLP-1 receptor antagonist, exendin-(9-39), affects food intake and body weight. Daily i.c.v. injection of 3 nmol GLP-1 to schedule-fed rats for 6 days caused a reduction in food intake and a decrease in body weight of 16 +/- 5 g (P < 0.02 compared with saline-injected controls). Daily i.c.v. administration of 30 nmol exendin-(9-39) to schedule-fed rats for 3 days caused an increase in food intake and increased body weight by 7 +/- 2 g (P < 0.02 compared with saline-injected controls). Twice daily i.c.v. injections of 30 nmol exendin-(9-39) with 2.4 nmol neuropeptide Y to ad libitum-fed rats for 8 days increased food intake and increased body weight by 28 +/- 4 g compared with 14 +/- 3 g in neuropeptide Y-injected controls (P < 0.02). There was no evidence of tachyphylaxis in response to i.c.v. GLP-1 or exendin-(9-39). GLP-1 may thus be involved in the regulation of body weight in the rat.     

Effects of age and ethanol on DNA single-strand breaks and toxicity induced by 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone or n-nitrosodimethylamine in hamster and rat liver

Treatment of Rhesus monkey peripheral blood lymphocytes and IL-2 dependent cell lines with heat prior to incubation with mitogens or IL-2, respectively, induces significant cell changes at the nuclear level, detected by DNA staining with Vindelov's propidium iodide and the simultaneous measurement of its red fluorescence and 90 degrees light scatter. These changes are an increase in their nuclear granularity and in apparently fragmented DNA which shows less fluorescence intensity than DNA from nuclei in the G0G1 phase, a phenomenon suggestive of apoptosis. Treated cells also show an increased number of nuclei in G1 or early S phase, with a reduction in those reaching the G2 or M phases. After heat-shock treatment, CTLL-2 cells show an increase in their response to low doses of recombinant IL-2 and an impaired ability to proliferate at higher IL-2 concentrations. These results provide further evidence for the regulatory role of stress-induced events.     

The localization of somatostatin receptor 1 (sst1) immunoreactivity in the rat brain using an N-terminal specific antibody

The biological actions of somatostatin are mediated via a family of G protein-coupled receptors named sst1 to sst5. We used an affinity-purified polyclonal antibody AS-65, directed against a specific N-terminal peptide sequence of sst1 to determine the immunohistochemical distribution of N-terminal sst1 immunoreactivity in the rat brain. The specificity of the antibody was shown by western blotting experiments using an N-terminal sst1 fusion protein. Enzymatic deglycosylation experiments were combined with blotting experiments on a sst1-transfected cell line and rat brain membrane proteins and with immunocytochemistry on an sst1-transfected cell line. These studies showed that the antibody detected the deglycosylated sst1 receptor protein. Immunohistochemical staining showed that sst1 immunoreactivity (presumably the deglycosylated receptor) recognised by this N-terminal antiserum was widely distributed throughout the brain with cells and processes labelled in the cerebral cortex, regions of the limbic system (including the hippocampal formation and some basal ganglia nuclei), the epithalamus, the thalamus, different subthalamic structures (subthalamic nucleus, zona incerta), the colliculi, the hypothalamus, the reticular formation, the cerebellum and regions of the trigeminal nerve complex. The distribution of immunoreactivity was in good general agreement with that predicted from the localization of sst1 messenger RNA and radioligand binding studies. This study on the immunohistochemical distribution of the sst1 receptor in the brain will provide a better understanding of the central actions of somatostatin at its receptor types.     

Factors secreted by human T lymphotropic virus type I (HTLV-I)-infected cells can enhance or inhibit replication of HIV-1 in HTLV-I-uninfected cells: implications for in vivo coinfection with HTLV-I and HIV-1

It remains controversial whether human T lymphotropic virus type I (HTLV-I) coinfection leads to more rapid progression of human immunodeficiency virus (HIV) disease in dually infected individuals. To investigate whether HTLV-I infection of certain cells can modulate HIV-1 infection of surrounding cells, primary CD4(+) T cells were treated with cell-free supernatants from HTLV-I-infected MT-2 cell cultures. The primary CD4+ T cells became resistant to macrophage (M)-tropic HIV-1 but highly susceptible to T cell (T)-tropic HIV-1. The CC chemokines RANTES (regulated on activation, normal T cell expressed and secreted), macrophage inflammatory protein (MIP)-1alpha, and MIP-1beta in the MT-2 cell supernatants were identified as the major suppressive factors for M-tropic HIV-1 as well as the enhancers of T-tropic HIV-1 infection, whereas soluble Tax protein increased susceptibility to both M- and T-tropic HIV-1. The effect of Tax or CC chemokines on T-tropic HIV-1 was mediated, at least in part, by increasing HIV Env-mediated fusogenicity. Our data suggest that the net effect of HTLV-I coinfection in HIV-infected individuals favors the transition from M- to T-tropic HIV phenotype, which is generally indicative of progressive HIV disease.     

One class of growth hormone (GH) receptor and binding protein messenger ribonucleic acid in rat liver, GHR1, is sexually dimorphic and regulated by GH

In the rat, alternatively spliced messenger RNA (mRNA) species encode GH receptor (GHR) and GH-binding protein (GHBP). Additionally, these mRNAs are alternatively spliced in the 5'-untranslated region, resulting in at least two classes of GHR and GHBP mRNA with distinct first exons and identical coding regions. These alternative first exons define two unique classes of GHR and GHBP mRNA (called GHR1 and GHR2). The GHR1 class of RNA is expressed only in the liver, is far more abundant in females than males, and is particularly abundant during pregnancy. GHR1 RNA is induced later in development than is GHR2. Additional classes of GHR and GHBP RNA may also exist. The genomic structure of the GHR1 first exon reveals a putative promotor region with no TATA box, CAAT box, or other sequence elements suggesting specific responses. An in vivo approach was used to investigate the regulation of GHR1 expression. In female rats, gonadectomy was found to reduce the percentage of steady state GHR1 RNA levels in the liver, whereas male castration resulted in an induction of GHR1 RNA. However, short-term treatment with estrogen or testosterone had little effect, suggesting that direct regulation of GHR1 expression may occur through effector(s) other than gonadal steroids. Hypophysectomy abolished GHR1 RNA in females. Treatment of hypophysectomized females and castrated males with GH by single injection did not significantly induce GHR1 RNA, but treatment by continuous infusion of GH did. Little change in non-GHR1 RNA levels was observed for each of these treatments. The results suggest that: 1) the sexual dimorphism observed in total GHR and GHBP RNA in rat liver is attributable to the sexually dimorphic expression of the GHR1 class of RNA; 2) the sexually dimorphic pattern of GH release in rats regulates the GHR1 class of RNA; 3) changes in GHR and GHBP expression observed on gonadectomy, hypophysectomy, GH treatment, and pregnancy are best attributed to GHR1 regulation; and 4) since GHR1 is liver specific, the observed increases in serum GHBP concentration in response to sex steroids, GH pattern, and pregnancy are likely to originate from the liver.     

Effects of haloperidol and d-amphetamine on in vivo 3H-spiroperiodol binding in the rat forebrain(1)

Specific (3)H-spiroperidol ((3)H-Sp) binding was demonstrated to occur, in vivo, throughout the rat forebrain. The highest concentrations of (3)H-Sp were found in regions known to contain dopamine neuron terminals. Acute and repeated administration of low does of haloperidol decreased in vivo (3)H-Sp in subcortical but not cortical regions. Repeated administration of high does of haloperidol followed by washout periods up to 8 days did not lead to an increase in in vivo (3)H-Sp binding; however, a single dose of d-amphetamine caused substantial increases. Analysis of the alterations induced by haloperidol and d-amphetamine suggest that the dopamine receptor changes configuration upon excessive exposure to agonists or antagonists in such a way as to favor the counterpart ligand.     

The haemagglutinins of influenza A (H1N1) viruses in the 'O' or 'D' phases exhibit biological and antigenic differences

Influenza A (H1N1) viruses when initially isolated in mammalian cell cultures (MDCK cells) had different agglutination reactions with chicken and guinea-pig erythrocytes compared to the same viruses after passage. On first isolation the virus HA resembled the 'O' phase viruses described originally by Burnet and Bull and agglutinated mammalian but not avian erythrocytes. After passage, the virus HA resembled a classical 'D' phase virus and agglutinated both avian and mammalian erythrocytes. Monoclonal and polyclonal antisera detected antigenic differences between the HAs of the viruses in the 'O' and 'D' phases. The 'O' phase virus HA reacted preferentially with antibodies in post infection human antisera. Viruses in the 'O' phase replicated poorly in the allantoic cavity of embryonated hens' eggs whilst 'D' phase virus replicated in both MDCK cells and in embryonated hens' eggs. At least three distinguishable subpopulations of influenza A (H1N1) viruses may co-exist in clinical throat swab material, including viruses possessing HAs in the 'O' and 'D' phases and other 'D' phase viruses cultivable in embryonated hens' eggs but antigenically distinguishable from the corresponding 'D' phase virus in MDCK cells.     

The effect of dizocilpine (MK-801) on conditional discrimination learning in the rat

OBJECTIVES: To report the effects of the anti-oestrogen tamoxifen on biochemical and haematological parameters. DESIGN: Randomized, double-blind comparison of tamoxifen 20 mg per day and placebo, over two years. SETTING: A university hospital. SUBJECTS: Forty-six healthy late-postmenopausal women (mean, SD time since menopause; 11, seven years). MAIN OUTCOME MEASURES: Blood specimens were drawn in the fasting state at baseline, six months and two years for measurement of haemoglobin, haematocrit, erythrocyte mean cell volume, mean erythrocyte haemoglobin, leucocyte count, platelet count, urea, electrolytes, creatinine and albumin. RESULTS: There was a significant decline in the haemoglobin concentration in the tamoxifen group (-4.4, 1.2 g/L; mean, SE) and its levels were lower in this group than in those receiving placebo (P = 0.004). Similarly, haematocrit, erythrocyte count and total leucocyte count were lower in those on placebo (P = 0.002, P = 0.01 and P = 0.01, respectively) and platelet count showed a similar trend (P = 0.08). In the tamoxifen group, the level of serum albumin fell significantly (-2.2, 0.4 g/L) and was lower throughout the study than that in the placebo group (P = 0.006). That of serum urea tended to fall (-0.4, 0.2 mmol L) but the between-groups comparison was not significant (P = 0.18). CONCLUSIONS: These data suggest that tamoxifen exerts a haemodilutory effect in normal postmenopausal women. Since a similar effect has been reported in response to postmenopausal oestrogen therapy, it is likely that the observed changes represent another oestrogenic effect of tamoxifen in postmenopausal women. Haemodilution may contribute to the reduced incidence of cardiovascular disease reported in tamoxifen-treated women, and, therefore, its assessment in the new oestrogen agonists/antagonists being developed for cardiovascular disease prevention may be important.     

The metabolic fate of the coronary vasodilator 4-(3,4,5-Trimethoxycinnamoyl)-1-(N-pyrrolidinocarbonylmethyl)piperazine (cinepazide) in the rat, dog and man

1. An oral dose of the coronary vasodilator 4-(3,4,5-trimethoxy[14C]cinnamoyl)-1-(N-pyrrolidinocarbonylmethyl)piperazine was well absorbed and more than 60% of the dose was excreted within 24 h. In 5 days, rats, dogs, and man excreted in the urine and faeces respectively 36.7% and 58.3%, 33.4% and 68.6%, and 61.3% and 38.1% dose. Faecal radioactivity was probably excreted via the bile. 2. Plasma concentrations of radioactivity reached a maximum within about 1 h in all three species and declined fairly rapidly (t0.5 less than 3 h). For several hours, more than 50% of the plasma radioactivity was due to unchanged drug. After correction for dose and body weight (normalization), peak plasma concentrations of unchanged drug in man, rat and dog were in the approximate ratio 100 :30:1. 3. Similar metabolites were excreted by the three species, but the relative proportions differed. Rats and man excreted 17.2% and 15.9% respectively as unchanged drug in the urine whereas dogs excreted only 3.6%. Rat bile and urine contained 4.3% and 9.8% dose respectively as glucuronides of the mono-O-demethylated compounds and dog and human urine contained 9.0% and 2.6% respectively of these metabolites. The corresponding pyrrolidone accounted for 2.5%, 5.5% and 5.1% respectively in rat, dog and human urine. Complete O-demethylation also occurred since 4-(3,4,5-trihydroxycinnamoyl)-1-(N-pyrrolidinocarbonylmethyl)piperazine was present in rat faeces (22.1% dose).