Role of secretin in negative feedback regulation of postprandial pancreatic secretion in dogs

BACKGROUND

A negative feedback regulation of pancreatic exocrine secretion has been observed in fasting rats, pigs, and humans, but this phenomenon could not be found in fasting dogs. The aims of the present study were to investigate whether or not postprandial pancreatic secretion is regulated by a negative feedback mechanism and to determine if the mechanism is mediated by secretion and/or cholecystokinin (CCK) in dogs.

METHODS

In eight dogs prepared with gastric and Herrera's pancreatic cannulas, pancreatic juice was collected for 3 hours after feeding a mixed meal to measure volume, bicarbonate, and trypsin output. Peripheral venous blood was obtained to determine plasma immunoreactive secretin and CCK levels. Four groups of experiments were performed while pancreatic juice was diverted from the duodenum: (1) diversion of pancreatic juice alone, (2) intraduodenal infusion of fresh pancreatic juice while pancreatic juice was diverted, (3) intraduodenal infusion of 150 mg/h of trypsin and 300 mg/h of chymotrypsin, and (4) intraduodenal infusion of 0.1 mol/L NaHCO3.

RESULTS

Pancreatic secretion during diversion of pancreatic juice was significantly greater than that obtained while pancreatic juice was returned. Diversion-induced pancreatic hypersecretion was significantly suppressed by intraduodenal administration of pancreatic proteases, but it was not influenced significantly by 0.1 mol/L NaHCO3. The suppression by either pancreatic juice or proteases paralleled the decrease in plasma secretin response, whereas the CCK response remained unchanged. The inhibitory effect of pancreatic proteases on pancreatic secretion was blocked by a physiological dose of exogenous secretin, 0.06 clinical U.kg-1.h-1.

CONCLUSIONS

In dogs, postprandial pancreatic secretion is controlled by a negative feedback mechanism mediated mainly by the release of secretin, but not by CCK.

Involvement of cytokines and vascular adhesion receptors in the pathology of fronto-ethmoidal mucocoeles

Fronto-ethmoidal mucocoeles have the capacity to destroy bone. Sinus lining tissue has been obtained at surgery from patients with mucocoeles, from those with chronic sinusitis undergoing endoscopic sinus surgery and from patients undergoing craniofacial resection. Tissues have been frozen, sectioned, and subjected to immunohistochemical examination with monospecific antibodies for the presence of the potent osteolytic cytokines interleukins-1 and -6 and tumour necrosis factor alpha. In addition, the chemotactic intercrine--interleukin-8 was investigated. The presence of the cytokine-inducible vascular endothelial adhesion receptors--Inter-Cellular Adhesion Molecule (ICAM)-1 and E-Selectin (also known as Endothelial Leukocyte Adhesion Molecule--ELAM) was also determined. Normal sinus tissue showed no immunoreactivity with the antibodies to these various moieties. Surprisingly, only a small proportion of tissues from patients with chronic sinusitis showed the presence of cytokines or vascular adhesion receptors. In contrast, all specimens of fronto-ethmoidal mucocoeles showed positive staining for IL-1 alpha and beta and for ICAM-1 and E-selectin. IL-1 immunostaining was restricted to the epithelial cell population not being found in infiltrating leukocytes. In 40% of mucocoeles infiltrating macrophage-like cells showed the presence of tumour necrosis factor alpha. The presence of the potent osteolytic cytokine--IL-1 in all specimens of fronto-ethmoidal mucocoeles coupled to the finding of the IL-1-inducible adhesion molecules ICAM-1 and E-Selectin argues strongly that IL-1 is released from the epithelial cells and that this cytokine may be the factor causing the erosion of bone overlying the expanding mucocoele. The nature of the signals inducing cytokine synthesis remain, however, unidentified.

[125I]iodomelatonin binding sites in mammalian and avian kidneys

[125I]Iodomelatonin binding sites have been identified and characterized in kidneys of birds and mammals. These binding sites in the kidneys of guinea pig, duck and chicken were found to be stable, reversible, saturable, specific and of high affinity. The binding densities (Bmax) of [125I]iodomelatonin binding sites in the kidneys of guinea pig, duck and chicken ranged from 1.07 to 6.43 fmol/mg protein and the equilibrium dissociation constants (Kd) from 19.2 to 44.6 pmol/l at the middle of the light period (mid-light). It appears that [125I]iodomelatonin binding in the kidneys of mammalian species may have lower densities compared with birds. In the mammals studied, the guinea pig kidney showed the highest [125I]iodomelatonin binding. Pharmacological data indicated that the [125I]iodomelatonin binding to kidneys of guinea pig, duck and chicken was highly specific to melatonin, 2-iodomelatonin and 6-chloromelatonin. Diurnal variations in the Bmax of [125I]iodomelatonin binding sites were detected in the kidneys of duck and chicken with no difference in affinity. However, there was no diurnal variation in the Kd or Bmax in the guinea pig kidneys. The density of [125I]iodomelatonin binding sites in the cortex of guinea pig kidney was more than 8-fold higher than the binding in the medulla. Guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S; 10 mumol/l) reduced the Bmax and increased the Kd of [125I]iodomelatonin binding sites in the chicken kidney. However, in the membrane preparations of the guinea pig kidney, co-incubation with GTP gamma S (15 mumol/l) increased the Kd with no effect on the Bmax of the [125I]iodomelatonin binding. The effects of GTP gamma S on the kidney [125I]iodomelatonin binding suggest that these binding sites may couple to a G protein. The identification of [125I]iodomelatonin binding sites in the kidneys of mammals and birds supports the possibility of melatonin acting directly on the renal system.

Immunocytochemical study with anti-muscle actin antibody (HHF35) on myocardial ischaemia and reperfusion injury in rats

Myocardial ischaemia and reperfusion injury in 16 anaesthetized Sprague-Dawley rats, eight of which were pretreated with morphine (5 mg/kg, intraperitoneally) to prevent arrhythmias, were studied immunocytochemically with anti-muscle actin specific monoclonal antibody (HHF35). Eight cases of simple ischaemia and eight cases of sham-operated rats were used as controls. With HHF35 ABC immunocytochemical method, the left ventricular myocardium in the reperfusion group (without morphine) showed large areas of staining loss, but no loss of staining was seen in controls. No significant changes were seen with H&E stain in all hearts. Compared with HBFP, acridine orange (AO), eosin-fluorescence, HHF35 ABC staining best demonstrated myocardial reperfusion injury. The results indicate that the degree of myocardial damage may be related to the arrhythmias.

Ionic channel currents in cultured neurons from human cortex

Ionic channels in human cortical neurons have not been studied extensively. HCN-1 and HCN-1A cells, which recently were established as continuous cultures from human cortical tissue, have been shown by histochemical and immunochemical methods to exhibit a neuronal phenotype, but expression of functional ionic channels was not demonstrated. For the present study, HCN-1 and HCN-1A cells were cultured in Dulbecco's modified Eagle's medium with 15% fetal calf serum, in some cases supplemented with 10 ng/ml nerve growth factor, 10 microM forskolin, and 1 mM dibutyryl cyclic adenosine monophosphate to promote differentiation. Cells or membrane patches were voltage clamped using conventional patch clamp techniques. In HCN-1A cells, we identified a tetrodotoxin-sensitive Na+ current, two types of Ca2+ channel current, including L-type current and a second type that in some respects resembled N-type current, and four types of K+ current, including a delayed outward rectifier that showed voltage-dependent inactivation, two types of noninactivating Ca(2+)-activated K+ channels with slope conductances of 146 and 23 pS (K+i/K+o 145 mM/5 mM), and less frequently, a noninactivating, intermediate conductance channel that was not sensitive to internal Ca2+. When HCN-1A cells were examined after 3 days of exposure to differentiating agents, pronounced morphological changes were evident but no differences in ionic currents were apparent. HCN-1 cells also exhibited K+ and Ca2+ channel currents, but Na+ currents were not detected in these cells.(ABSTRACT TRUNCATED AT 250 WORDS)

[Pre-and postoperative indocyanine green retention rate as a marker of liver functional reserve in cirrhotic patients]

Indocyanine green ICG retention rate was determined before and after in portohypertensive cirrhotic patients undergoing paracardial devascularization (PCDV) and side-to-side mesocaval shunt (MCs-ss). The relationship between ICG retention rate with serum albumin level and the incidence of ascites was investigated no significant change the rate was noted before and after. Operation in PCDV patients. Significant increase of the rate was observed after MCs-ss. There was a negative correlation between the rate and serum albumin level. Addition the incidence of ascites increased with the elevation of the rate, there was a significant difference in the rate in patients with or without ascites.

Characterization of a virG mutation that confers constitutive virulence gene expression in Agrobacterium

Transformation of plants by Agrobacterium tumefaciens is mediated by a set of virulence (vir) genes that are specifically induced by plant signal molecules through the VirA/VirG two-component regulatory system. The plant signal is transmitted from VirA to VirG by a cascade of phosphorylation reactions followed by the sequence-specific DNA binding of the VirG protein to the vir gene promoters which then activates their transcription. In this report, we describe a VirG mutant which is able to activate vir gene expression independently of the VirA molecule and the two plant signal molecules, acetosyringone and monosaccharides. A strain of Agrobacterium containing this virG gene but lacking a functional virA gene was able to induce tumours on all three plants that were tested. A single amino acid change of asparagine (N) to aspartate (D) at position 54, adjacent to the site of VirG phosphorylation, aspartate 52, resulted in this constitutive phenotype. In vitro phosphorylation experiments showed that the mutant protein cannot be phosphorylated by VirA, suggesting that the negative charge resulting from the N to D switch mimics the phosphorylated conformation of the VirG molecule. The same amino acid change in the virG gene of the supervirulent strain A281 also resulted in a constitutive phenotype. However, the vir genes were not induced to high levels when compared with the levels of the constitutive virG of strain A348.

Monoclonal antibody specific to alpha-2-->3-linked deaminated neuraminyl beta-galactosyl sequence

Fusion of spleen cells from a BALB/c mouse immunized with KDN alpha 2-->3Gal beta 1-->4Glc beta 1-->1Cer ((KDN)GM3) with P3-X63 Ag8.U1 (P3U1) mouse myeloma cells yielded a hybrid cell line that produced monoclonal antibody that bound to (KDN)GM3, but not to Neu5Ac alpha 2-->3Gal beta 1-->4Glc-beta 1-->1Cer ((Neu5Ac)GM3). The specificity of the monoclonal antibody was determined chiefly by the enzyme-linked immunosorbent assay procedure. This antibody was found to react most strongly with (KDN)GM3 and less strongly with a glycoprotein containing a number of KDN alpha 2-->3Gal beta 1-->3-GalNAc alpha 1-->3[8KDN alpha 2-->)n-->6]GalNAc alpha 1-->chains (< n > av = approximately 3). The results indicated that the monoclonal antibody (designated mAb.kdn3G) specifically and effectively recognized a disaccharide structure, KDN alpha 2-->3Gal beta 1-->, and specifically discriminated (KDN)GM3 from (Neu5Ac)GM3. The mAb.kdn3G was used to localize (KDN)GM3 in rainbow trout sperm by the indirect immunofluorescence procedure and the antigen was shown to be mostly, if not completely, associated with the external surface of the entire plasma membrane of rainbow trout sperm. The potential utility of mAb.kdn3G is addressed in searching for KDN-glycoconjugates which contain glycan units having the KDN alpha 2-->3Gal beta 1-->epitope structure.

Pharmacokinetic characteristics and antitumor activity of the N-succinyl-chitosan-mitomycin C conjugate and the carboxymethyl-chitin-mitomycin C conjugate

The conjugate between N-succinyl-chitosan (Suc-chitosan) and mitomycin C (MMC), named Suc-chitosan-MMC, and that between carboxymethyl-chitin (CM-chitin) and MMC, named CM-chitin-MMC, were investigated in vivo. As for the intraperitoneal drug administration using rats, the order of the maximum blood concentration of MMC was unconjugated MMC > CM-chitin-MMC > Suc-chitosan-MMC. The plasma concentration of MMC for Suc-chitosan-MMC was maintained at an almost constant level over 24 h. Pharmacokinetic analysis of each plasma concentration indicated that for each conjugate, the in vitro drug release reported previously was useful for the approximate estimation of the in vivo regeneration of MMC. The chemotherapeutic effect of MMC and the conjugates was investigated using mice bearing L1210 leukemia or B16 melanoma. Concerning antitumor activity against L1210 leukemia, the conjugates exhibited a marked effect at higher doses, and their effect increased even in the dose range where the effect of MMC decreased. MMC and the conjugates exhibited a good growth-inhibitory effect against B16 melanoma. Complete inhibition of growth of B16 melanoma was observed at the dose of 10 mg eq MMC/kg for CM-chitin-MMC.

Effects of guanosine 5'-O-(3-thiotriphosphate) on 2-[125I]iodomelatonin binding in the chicken lung, brain and kidney: hypothesis of different subtypes of high affinity melatonin receptors

Effects of 10 mumol/l guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S), a non-hydrolyzable analog of guanosine 5'-triphosphate, on 2-[125I]iodomelatonin binding were investigated. In the chicken lung, 10 mumol/l GTP gamma S significantly increased (p < 0.05) the equilibrium dissociation constant (Kd) values, but did not affect the maximum number of binding sites (Bmax). Conversely, in the chicken brain, GTP gamma S significantly depressed (p < 0.05) the Bmax, but did not change the Kd of the 2-[125I]iodomelatonin binding sites in the brain tissue. A third variation was observed in the chicken kidney with GTP gamma S altering (p < 0.05) both the Kd and the Bmax of 2-[125I]iodomelatonin binding sites. The reason underlying the different effects of GTP gamma S on 2-[125I]iodomelatonin binding in the tissue preparations is not clear. However, we would like to hypothesize that they may represent distinct subtypes of the ML-1-type melatonin receptor with different receptor-G-proteins-effector complex. The group represented by the 2-[125I]iodomelatonin binding sites found in the chicken lung, which is downregulated by GTP gamma S with a consequent increase in the Kd value, has been designated ML-1 alpha. The second group, exemplified by the brain 2-[125I]iodomelatonin binding sites, which respond to GTP gamma S with a change in Bmax, has been labelled ML-1 beta. The third group, characterized by GTP gamma S-mediated alterations in both Bmax and Kd and found in the chicken kidney, has been called ML-1 gamma. Different subtypes of melatonin receptors may address the issue of the different physiological actions of melatonin reported in individual tissues within the same species or similar tissues but different species. Specialized responses could be generated depending on the predominant subtype of ML-1 receptors associated with the target tissue.

[The nutritional status and immune function of patients with chronic obstructive pulmonary disease]

The nutritional status and immune function of 14 patients with exacerbation of chronic obstructive pulmonary disease (COPD) were assessed and were studied again one week after the patients had recovered. The results showed that the nutritional status of the patients was poorer on admission, the level of some kinds of serum free amino acid was significantly lower than the normal value, the value of branch-chain amino acid (BCAA) was significantly lower than that in healthy people (P < 0.01), but the level of aromatic amino acid (AAA) was higher than the normal value. Level of serum free fatty acid was significantly lower during admission and in recovery period (P < 0.01). It is suggested that shortage of essential fatty acid in the patients is obvious. The results also showed that the patients identified as malnourished had a lower cellular immune function, but the humoral immune function was not significant between the patients group and control group. Immune function was improved with the recovery nutritional status of the patients. The results suggest that malnutrition and hypoimmunity may play a very important role in the pathogenesis of COPD.

Selective A2-adenosine receptor agonists do not alter action potential duration, twitch shortening, or cAMP accumulation in guinea pig, rat, or rabbit isolated ventricular myocytes

In this study, the hypothesis that mammalian ventricular myocytes possess A2-adenosine receptors was tested. Electrophysiological, contractile, and cAMP responses to the selective A2-adenosine receptor agonists 2-[2-(4-methylphenyl)ethoxy]adenosine (WRC-0090) and 2-(2-cyclohexylethoxy)adenosine (WRC-0013) and the nonselective adenosine receptor agonist 5'-(N-ethylcarboxamido)adenosine (NECA) were measured using ventricular myocytes isolated from guinea pig, rabbit, and rat hearts. Pertussis toxin pretreatment and/or the selective A1-adenosine receptor antagonists 1,3-dipropyl-8-cyclopentylxanthine (DPCPX) and (+/-)N6-endonorbornan-2-yl-9-methyladenine (N-0861) were used to prevent activation of A1-adenosine receptors in these cells. Action potential duration at 50% repolarization was not altered by WRC-0090, NECA, or WRC-0013 with or without 0.1 microM DPCPX or pertussis toxin pretreatment, and WRC-0090 and NECA failed to prolong the action potential duration of myocytes exposed to 0.1 or 1 microM forskolin. WRC-0090 alone or with 0.1 microM DPCPX did not increase the amplitude of shortening of pertussis toxin-treated or untreated myocytes, and WRC-0090 or NECA did not significantly increase cAMP accumulation. In contrast to these results with myocytes, in the smooth muscle cell line DDT1MF-2 the effect of both selective A2-agonists on cAMP accumulation was biphasic: low concentrations (< or = 0.3 microM) increased but higher concentrations decreased accumulation of cAMP. The decreased cAMP accumulation seen at higher agonist concentrations was completely abolished by either 0.1 microM DPCPX or pretreatment of cells with pertussis toxin. In summary, the results of the present study do not provide evidence for A2-adenosine receptors on mammalian ventricular cardiomyocytes but confirm reports of the coexistence of both A1 and A2 subtypes of adenosine receptors on DDT1MF-2 cells.

The identification and characterization of 125I-labelled iodomelatonin-binding sites in the duck kidney

The melatonin-binding sites in membrane preparations of duck kidney were demonstrated by utilizing 125I-labelled iodomelatonin as a radioligand. Binding at these sites was found to be reversible, saturable, specific and of high affinity. Scatchard analysis of the specific binding revealed an equilibrium binding constant (Kd) of 44.6 +/- 4.4 pmol/l (n = 6) and a total number of binding sites (Bmax) of 6.43 +/- 0.60 fmol/mg protein (n = 6) at the mid-point of the light period (mid-light). The Hill coefficient approached 1.0, suggesting a single class of 125I-labelled iodomelatonin-binding site in the duck kidney. Diurnal variation in 125I-labelled iodomelatonin binding showed that the Bmax was 53.4% higher at mid-light than at mid-point of the dark period (P < 0.05), with no significant variation in Kd. The Kd value determined from kinetic analysis was 22.5 pmol/l in birds at mid-light, which was comparable with values determined from equilibrium studies. The order of pharmacological affinity for 125I-labelled iodomelatonin-binding sites in the duck kidney membrane preparations was: 2-iodomelatonin > melatonin > 6-chloromelatonin > 6-hydroxymelatonin > N-acetylserotonin >> 5-methoxytryptamine, 5-methoxytryptophol, 5-hydroxytryptamine, tryptamine, 1-acetylindole-3-carboxaldehyde, 5-hydroxyindole-3-acetic acid, L-tryptophan, 5-methoxyindole-3-acetic acid, 3-acetylindole, acetylcholine, epinephrine, norepinephrine and harmaline. The pharmacological characteristics indicated that 125I-labelled iodomelatonin-binding sites are highly specific for melatonin. Our finding of 125I-labelled iodomelatonin-binding sites in the kidney suggests that melatonin may regulate kidney function.(ABSTRACT TRUNCATED AT 250 WORDS)

[125I]iodomelatonin-binding sites in the chicken kidney: characterization and comparison to other avian species

The existence of [125I]iodomelatonin-binding sites in the kidney of the chicken and other avian species has been demonstrated in the present study. [125I]Iodomelatonin-binding sites in membrane preparations of the chicken kidney were reversible, saturable, specific and of high affinity. Scatchard analysis of the specific binding revealed an equilibrium binding constant (Kd) of 30.3 +/- 5.1 pmol/l (n = 5) and a total number of binding sites (Bmax) of 2.89 +/- 0.24 fmol/mg protein (n = 5) at the middle of the light period (mid-light). The Hill coefficient approached 1.0, suggesting a single class of [125I]iodomelatonin-binding sites in the chicken kidney. The diurnal variation study showed that the Bmax was 52% higher at mid-light than that in the middle of dark period (1.90 +/- 0.33 fmol/mg protein, n = 4; p < 0.05), with no significant variation in Kd. The Kd value determined from kinetic analysis was 10.8 pmol/l in the mid-light birds, which was comparable to values determined from equilibrium studies. The competition inhibitor experiments demonstrated that [125I]iodomelatonin-binding sites were highly specific for melatonin with the following order of potency: 2-iodomelatonin > melatonin, 6-chloromelatonin > 6-hydroxymelatonin N-acetylserotonin >> 5-methoxytryptamine, 5-methoxytryptophol, 5-hydroxyindole-3-acetic acid, 5-hydroxytryptamine, 1-acetylindole-3-carboxaldehyde, 3-acetylindole, tryptamine, 5-methoxyindole-3-acetic acid, L-tryptophan, harmaline, acetylcholine, epinephrine and norepinephrine. Studies on the relative binding density of [125I]iodomelatonin to the kidney in different species of birds showed the following descending order: duck > chicken > pigeon > quail.(ABSTRACT TRUNCATED AT 250 WORDS)

Enhanced self-pumped phase conjugation from 16 degrees -cut KNSBN:Cu

With the maximum coupling coefficient and high internal reflection conditions, the self-pumped phase-conjugation reflectivity of copper-doped potassium sodium strontium barium niobate (KNSBN:Cu) is increased with 16 degrees -cut samples. The response time is also shortened. The resolution property of 16 degrees -cut KNSBN:Cu is determined and a distorted image is corrected by using the 16 degrees -cut sample.

Synthesis and drug-release characteristics of the conjugates of mitomycin C with N-succinyl-chitosan and carboxymethyl-chitin

By condensation of mitomycin C (MMC) with N-succinyl-chitosan (Suc-chitosan) and carboxymethyl-chitin (CM-chitin) using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, Suc-chitosan-MMC conjugate (Suc-chitosan-MMC) and CM-chitin-MMC conjugate (CM-chitin-MMC) were prepared, respectively. The reaction conditions for 45 min at pH 5 and for 2 h at pH 5 were selected as the most appropriate for the preparations of Suc-chitosan-MMC and CM-chitin-MMC, respectively. Suc-chitosan-MMC was obtained as a water-insoluble product, while CM-chitin-MMC was partially water-soluble. When the ratio of MMC to the polymer supports changed in the conjugation reaction, the conjugates with 33% (w/w) and 23% (w/w) MMC contents were obtained as those most highly drug-loaded for Suc-chitosan-MMC and CM-chitin-MMC, respectively. At pH 7.4 at 37 degrees C, Suc-chitosan-MMC regenerated MMC very slowly, while the release of MMC from CM-chitin-MMC was relatively fast. Each drug release followed very nearly pseudo-first order kinetics, in which the apparent drug release rate constants (k(apps)) of Suc-chitosan-MMC and CM-chitin-MMC were 3.9 x 10(-3) and 1.1 x 10(-1) (h-1), respectively.

Sequence and expression of a rat cDNA for LECAM-1

A rat cDNA clone encoding an adhesion molecule, LECAM-1, has been isolated from the SD rat and the partial nucleotide sequence was determined. It encodes a peptide of 372 amino acids (aa), including a signal peptide of 38 aa. The protein has three tandem domains: a lectin domain, an EGF-like domain and two repeats of complement regulatory proteins (CR domain). The lectin binding domain has 93.2% and 81.4% and the EGF-like domain has 85.3% and 76.5% aa identity with those of mouse and human, respectively. In the CR repeat domain, the amino acid identity was 72.6% between human and rat and 71.8% between mouse and rat. Northern blot analysis detects the main transcript of about 3 kb in peripheral blood mononuclear cells (PBMC), spleen and thymus. The expression was down-regulated by mitogen stimulation of PBMC and spleen T cells. The protein encoded by this cDNA interacted with PPME when it was expressed on gp90MEL-14 negative mouse EL-4 cells.

[Noradrenaline fluorescence histochemical study on the locus coeruleus of kindling rat induced by coriaria lactone]

Fourteen male Wistar rats were divided into two groups. The experimental rats were injected with subconvulsive dosage of coriaria lactone (1 mg/kg) intramuscularly per 3.5 days. The controls were injected with normal saline. After 26 injections, the loci coeruleus of kindling rats were studied with the noradrenaline (NA) fluorescence histochemical technique at the time between seizures. The NA fluorescence could be clearly visualized under fluorescent microscope. The intensity of fluorescence was reflected by autoexposure-meter of the fluorescent microscope. The brighter the fluorescence, the shorter the autoexposure time. The intensity of NA fluorescence in the locus coeruleus of experimental animals was weaker than that of the controls. Since NA plays an inhibitory role in cerebral cortex, the decrease of NA, either induced by repeated injections of coriaria lactone or due to the time of sample taken after seizure, needs further study.

[Histochemical and image-analytic study of the rat locus coeruleus during status epilepticus]

Twenty-four adult male Wistar rats were used in this study. Status epilepticus was provoked in 10 rats by embedding coriaria lactone particle into the left cerebral motor cortex. In the controls were embedded particles without coriaria lactone. After 6 h of continuous seizure, the locus coeruleus was studied with the noradrenaline (NA) fluorescence histochemical technique and enzyme histochemical test for monoamine oxidase (MAO). The intensity of NA fluorescence was detected with fluorescent microscope autoexposuremeter and analysed with MIAS-200 Image Analyser. The study group showed a parallel increase of NA fluorescence as compared with that of the control group by both measurements. NA plays an inhibitory role in the cortex. Our data suggest that the increase of NA in locus coeruleus may be due to the reduction of NA release from axon terminal. Reduction in inhibition could be one of the mechanisms of seizure activity. The intensity of MAO was detected with MIAS-200 Image Analyser. The regulation of monoamine metabolism by MAO in the central nervous system and the increase of MAO activity in the continuous seizure group may be induced by the accumulation of NA in the locus coeruleus soma.

Adenosine-sensitive afterdepolarizations and triggered activity in guinea pig ventricular myocytes

This study examines the cellular basis and specificity of the effects of adenosine on early afterdepolarizations (EADs), delayed afterdepolarizations (DADs), and triggered activity (TA) induced by various drugs with different mechanisms of action. Membrane potential and currents were measured in isolated guinea pig ventricular myocytes. Adenosine (10-100 microM) significantly (p less than 0.05) reduced the amplitude of DADs and suppressed TA induced by isoproterenol (10-50 nM) and forskolin (1 microM) but not those induced by dibutyryl cAMP (1 microM), ouabain (1-5 microM), and 7.2 mM [Ca2+]o. Adenosine also abolished EADs and TA induced by isoproterenol. In contrast, adenosine failed to abolish EADs and TA induced by quinidine (3 microM) or those that occurred spontaneously (i.e., in the absence of drugs). Transient inward current (ITi) was induced on repolarization after 2-second-long single depolarizing voltage steps or after 12-second-long trains of 300-msec depolarizing pulses. Concomitant with the attenuation of DADs, adenosine suppressed ITi caused by isoproterenol and forskolin but not those induced by ouabain, dibutyryl cAMP, and elevated [Ca2+]o. The amplitude of ITi was dependent on the magnitude of the activating voltage step, but the suppression of ITi by adenosine was not. The selective A1-adenosine receptor antagonist N-0861 (9-methyladenine derivative) antagonized the effects of adenosine on afterdepolarizations, ITi, and TA. In myocytes from guinea pigs treated with pertussis toxin, adenosine failed to attenuate DADs and ITi or abolish TA induced by isoproterenol or forskolin. In parallel experiments, isoproterenol (10 nM) raised cellular cAMP from 5.7 +/- 0.2 to 8.1 +/- 0.1 pmol and the selective A1 receptor agonist cyclopentyladenosine (5 microM) reduced it to 6.5 +/- 0.2 pmol (p less than 0.05). Thus, adenosine specifically attenuates afterdepolarizations and abolishes TA by suppressing ITiS that are associated with stimulation of adenylate cyclase via a pertussis toxin-sensitive A1 receptor-mediated action. In conclusion, the response of TA to adenosine may identify a mechanism of afterdepolarization related to stimulation of adenylate cyclase.

Sequence and organization of 5S ribosomal RNA-encoding genes of Arabidopsis thaliana

We have isolated a genomic clone containing Arabidopsis thaliana 5S ribosomal RNA (rRNA)-encoding genes (rDNA) by screening an A. thaliana library with a 5S rDNA probe from flax. The clone isolated contains seven repeat units of 497 bp, plus 11 kb of flanking genomic sequence at one border. Sequencing of individual subcloned repeat units shows that the sequence of the 5S rRNA coding region is very similar to that reported for other flowering plants. Four A. thaliana ecotypes were found to contain approx. 1000 copies of 5S rDNA per haploid genome. Southern-blot analysis of genomic DNA indicates that 5S rDNA occurs in long tandem arrays, and shows the presence of numerous restriction-site polymorphisms among the six ecotypes studied.

[Clinical significance on expression of the ras gene product P21 in human cervical carcinoma tissues]

Using MAB-P21 as a probe, the expression of gene product was studied by immunohistochemical ABC method, ABC staining of gel electrophoresis and ELISA quantitative analysis. The expression of P21 was detected in 107 cases of uterine cervix tissues, among which 70 were cervical carcinoma, 30 were chronic cervicitis and 7 normal cervix. Experimental results showed that obviously positive expression was noted in the specimens of cervical carcinoma and its positive rate was 72.8% (51/70). It was observed that the expression of P21 varied with grades of cell differentiation in cervical carcinoma. The level of P21 expression in high differentiated type was higher than that of the middle and low differentiated types. On the contrary, there was no detectable ras P21 in the normal cervix tissue and only 2 cases of cervicitis expressed positively (2/30). The results of ABC staining of electrophoresis showed that there was a P21 special staining band in cervical carcinoma tissues. And the contents of P21 protein were higher in cervical carcinoma than in normal cervix and cervicitis (t test, P less than 0.001). The expression of P21 was considerably enhanced in malignant tissue as compared with that in benign lesion.

[A preliminary epidemiological survey of acute hemorrhagic conjunctivitis in Guangzhou during July to September in 1988]

An epidemic of acute hemorrhagic conjunctivitis (AHC) occurred in Guangzhou from July to September in 1988. The main clinical symptoms were feeling of foreign, smart pain, discharging ege, facial edema and conjunctival congestion. In some cases there were headache and fever. The patients recovered rapidly. Epidemiologic feature were that the incubation period of AHC is short, rapid spread, wide prevalence and high attack rate. Approximately 490000 cases of AHC are estimated to occur in Guangzhou from July to September in 1988, with the attack rate is about 79.5%. Most patients were 20 to 59 age group (72.3%). The highest age of patient was 79 years old. The lowest age of patient was 6 months old. Both etiologic and serologic studies showed that this outbreak of AHC was caused by EV70, and then developed a mixed epidemic of Cox A24 and EV70.

[Effects of intravenous flecainide acetate in patients with concealed atrioventricular pathway with supraventricular tachycardia]

The acute efficacy and electrophysiologic effects of intravenous flecainide acetate (1.5 mg/kg) on 10 patients with concealed AV pathway with supraventricular tachycardia (SVT) by esophageal programmed electrical stimulation were evaluated. The results showed that: (1) the drug has marked depressing effects on the retrograde accessory pathway conduction and minimal effects on the antegrade AV nodal conduction; (2) there were no effects on the patients with normal sinus node function; (3) the drug has little side effects during the studies; (4) flecainide terminated induced SVT in 9 of 10 cases (90%), and prevented induced SVT in 7 of 9 cases (78%).

Isolation and structural elucidation of a novel type of ganglioside, deaminated neuraminic acid (KDN)-containing glycosphingolipid, from rainbow trout sperm. The first example of the natural occurrence of KDN-ganglioside, (KDN)GM3

Rainbow trout sperm contained almost exclusively monoanionic ganglioside fraction as a major acidic glycosphingolipid. Two monoacidic gangliosides were isolated and purified in this study and designated as sperm ganglioside 1 and 2 (sg-1 and sg-2). The two gangliosides, sg-1 and sg-2, contained the same neutral sugars, galactose and glucose in molar ratio of 1:1 and no GalNAc except for the presence of N-acetyl-neuraminic acid (NeuAc) in sg-1 and deaminated neuraminic acid (KDN; 2-keto-3-deoxy-D-glycero-D-galacto-nononic acid) in sg-2. The complete structures of these gangliosides were determined by a combination of methylation analysis, fast atom bombardment mass spectrometry, 400-MHz one- and two-dimensional 1H nuclear magnetic resonance spectroscopy, fatty acid analysis, and endoglycoceramidase digestion NeuAc alpha 2----3Gal beta 1----4Glc beta 1----Cer sg-1 [(NeuAc)GM3] KDN alpha 2----3Gal beta 1----4Glc beta 1----Cer sg-2 [(KDN)GM3] where, for both sg-1 and sg-2, the ceramide moieties (Cer) were found to be made up of 4-sphingenine and mainly C16:0 fatty acid (palmitate; 95%) with a minor amount of C24:1 fatty acyl chain (nervonate, 5%). The structure of sg-2 is novel and represents the first example of a new class of gangliosides, i.e. KDN-gangliosides.

[Pre- and postoperative splanchnic hemodynamics measured by indocyanine green clearance in patients with portal hypertension]

In this study, plasma indocyanine green clearance (PIGC) and hepatic blood flow (HBF) were measured in patients with portal hypertension before and after pericardial devascularization or side-to-side mesocaval shunt (MS), and the relationship between PIGC and plasma albumin level was investigated. It was found that there was no change in PIGC after the patients underwent pericardial devascularization (portoazygous disconnection). There were a significant decrease of PIGC (averaging 16.28 +/- 8.3%,) and a decrease of HBF (averaging 17.71%, p less than 0.001) after the patients underwent MS. It was also found that there was a positive relationship between PIGC and plasma albumin level in patients with portal hypertension.

[Preventive effect of bombesin on alloxan-induced diabetes in rat]

The effect of bombesin against injury on rat islet B cells was studied in three kinds of experiments: (1). In vivo experiment, it was found that preinjection of bombesin (50 micrograms/kg, sublingual v.) could effectively prevent an increase of plasma glucose and decrease of plasma insulin in diabetic rat induced by alloxan (200 mg/kg, s.c.) (2). In vitro experiment, isolated pancreas perfusion showed that alloxan-induced (14 mmol/L) perfusion fluid inhibition of insulin secretion could be reversed by pretreatment of bombesin (10(-3) mmol/L). (3). Investigation on isolated and incubated islets demonstrated that alloxan induced decrease of insulin and somatostatin secretion and increase of glucagon secretion could be prevented by bombesin. The above-mentioned results suggest that bombesin may play an important role in the regulation of plasma glucose in diabetic rat and have a potent preventive effect against the development of diabetes.

[The investigation of anti-hepatitis A virus antibody rate in Guangzhou population]

The positive rate of Anti-HAV in 1663 general Guangzhou population were investigated by ELISA in 1988. The total positive rate of anti-HAV antibody ways 65.1%. There are great differences between the overall positive rate of anti-HAV antibody and those in different districts and counties. Among them, the highest rate was 90.2%, the lowest was 46.7%. The overall positive rate of anti-HAV antibody of rural population (79.3%) was significant higher than that of urban population (53.9%). The rates in scattered children (46.5%) were higher than in the organized children (20.8%). Among the less than 4 years old children, boys (39.0%) were higher than the girls (13.3%). Among 0-10 years old children, it presented a tendency of anti-HAV antibody rate from 15.4% to 44.4%, it increased rapidly to 29.73% in children aged 0-4. Among 10-49 years old group, the rate was going up with age. The value of the peak of positive rate of Anti-HAV antibody situated on 45-49 years of age, and after fifty the rate slowly decreased.

High-performance self-pumped phase conjugator with a multichannel in KNSBN:Cu crystal

A Cu-doped (0.04 wt. %) (K(0.5)Na(0.5))(0.2)(Sr(0.61) Ba(0.39))(0.9)Nb(2)O(6) crystal produced as much as 68% self-pumped phaseconjugate reflectivity at the laser wavelength lambda = 514.5 nm. We also observed some phenomena that helped us to understand the mechanism for the self-pumped phase-conjugate mirror.

[The partial characterization of neutrophils' and lymphocytes' chemotactic factors from murine anagenic hair bulb extract]

Sephadex G-75 gel filtration of murine anagenic hair bulb extracts (HBE) showed two peaks with chemotactic activity. Peak I (m.w. 63 +/- 4.6 KD) was chemotactic for both neutrophils and lymphocytes, and Peak II (m.w. 47 +/- 5.6 KD) was chemotactic for lymphocytes only. The neutrophil related chemotactic activity was sensitive to treatments by trypsin, pronase, neuraminidase, or heating at 100 degrees C for 10 min. With Peak I, lymphocyte related chemotactic activity was sensitive to treatments by pronase, trypsin or neuraminidase, but was unaffected by heating at 100 degrees C for 10 min. On the other hand, the same aforementioned treatments all individually inactivated the Peak II lymphocyte related chemotactic activity. Intradermal injection of Peak I fractions into guinea pigs induced infiltration of neutrophils and mononuclear cells, and that of Peak II induced the infiltration of mononuclear cells. These findings suggest that normal C3H murine anagenic hair bulb contains three different chemotactic factors related to neutrophils and lymphocytes.

[External counterpulsation in treating angina pectoris evaluated by Tl-201 myocardial perfusion imaging]

Twenty patients with angina pectoris were treated with external counterpulsation (ECP) for 36 hours, and the effects of the therapy were evaluated by comparing the images of thallium-201 myocardial perfusion before and after ECP. Improvement of myocardial perfusion after ECP, evidenced by decrease in area of defects in scintigram, was demonstrated in 15 (75%) cases. The mechanism of the effect of ECP on ischemic myocardium was discussed.

[The contents of gamma-aminobutyric acid and glutamic acid in brain affected by coriaria lactone]

Capillary chromatography was applied to studying the contents of gamma-aminobutyric acid (GABA) and glutamic acid (Glu) in brain affected by coriaria lactone. The results showed that there was a significant increase in the content of Glu whereas no significant change in the content of GABA was noted. The precisions for GABA and Glu were 3.3% and 4.98% and the recoveries of them were 80.5% and 85.2%, respectively. Capillary chromatography is a good method for determining the contents of GABA and Glu in brain, which has the characteristics of rapid and high sensitivity.

Extracellular matrix and androgen receptor expression associated with spontaneous transformation of rat prostate fibroblasts

Spontaneous transformation in continuous culture of the androgen-sensitive rat prostate fibroblast cell line, NbF-1, resulted in an aggressively tumorigenic nonmetastatic phenotype that coincided with few gross chromosome abnormalities. This study identified transformation-associated alterations in extracellular matrix and androgen receptor expression in the NbF-1 cell line. Substantial levels of procollagens I, III, and IV and fibronectin mRNAs were detected in nontumorigenic NbF-1 cells. Laminin B1 and B2 mRNAs were also detectable, but at lower levels. Expression of all six extracellular matrix mRNAs was nonuniformly lower in tumorigenic NbF-1 cells. This decrease in expression was greatest for alpha 2 procollagen IV mRNA, which was reduced 17-fold. Proteoglycans and glycosaminoglycans synthesized by the NbF-1 cultures were also characterized. The NbF-1 cell line expressed chondroitin sulfate proteoglycans predominantly, and expression was reduced 5- to 10-fold in tumorigenic cultures. In contrast to the extensive alterations in the extracellular matrix, measurement of high-affinity androgen binding and androgen receptor mRNA levels showed substantial expression of androgen receptors in both NbF-1 cultures. Cultures of early and late passage NbF-1 cells demonstrated a mitogenic response to dihydrotestosterone. These data indicate (a) that alterations in expression of extracellular matrix components may represent early markers for tumorigenic transformation in prostatic mesenchymal cells and (b) that these changes can occur without disrupting androgen receptor expression and androgen sensitivity.