Effect of a Change in the Sleep/Wake Cycle on the Diurnal Variation of Fibrinolytic Parameters

The mechanism underlying the circadian rhythm of fibrinolysis is not well understood. To evaluate the influences of wakefulness and of the intrinsic circadian rhythm on fibrinolytic activity, we examined diurnal changes (8:00 am vs. 8:00 pm) in plasminogen activator inhibitor-1 (PAI-1) activity, tissue plasminogen activator (t-PA) antigen levels, and t-PA activity, as well as in plasma serum cortisol levels, in 10 healthy males (21 ± 2 years) for two consecutive days. On the first day, subjects remained awake all day and night. They slept during the daytime (8:30 am to 5:30 pm) on the following day. PAI-1 activity and cortisol levels were significantly decreased, and t-PA activity tended to increase during the daytime on the first day. On the morning following overnight wakefulness, PAI-1 activity and cortisol levels did not return to the levels of the previous morning. On the second day, the afternoon decrease in PAI-1 activity, but not cortisol levels, was still observed, although its magnitude was substantially attenuated. No significant diurnal changes were observed in the levels of t-PA antigen throughout the study period. These findings suggest that the diurnal variation of fibrinolytic activity may be governed by an intrinsic circadian rhythm of PAI-1, which can be modified by a change in the time of wakefulness.     

Effect of sumatriptan on gastric emptying: a crossover study using the BreathID system

AIM:To determine the effect of oral sumatriptan on gastric emptying using a continuous 13 C breath test(BreathID system).METHODS:Ten healthy male volunteers participated in this randomized,2-way crossover study.The subjects fasted overnight and were randomly assigned to receive a test meal(200 kcal/200 mL) 30 min after pre-medication with sumatriptan 50 mg(sumatriptan condition),or the test meal alone(control condition).Gastric emptying was monitored for 4 h after administration of the test meal by the 13 C-acetic acid breath test performed continually using the BreathID system.Then,using Oridion Research Software(β version),the time taken for emptying of 50% of the labeled meal(T 1/2) similar to the scintigraphy lag time for 10% emptying of the labeled meal(T lag),the gastric emptying coefficient(GEC),and the regression-estimated constants(β and κ) were calculated.The statistical significance of any differences in the parameters were analyzed using Wilcoxon’s signed-rank test.RESULTS:In the sumatriptan condition,significant differences compared with the control condition were found in T 1/2 [median 131.84 min(range,103.13-168.70) vs 120.27 min(89.61-138.25);P = 0.0016],T lag [median 80.085 min(59.23-125.89) vs 61.11 min(39.86-87.05);P = 0.0125],and β [median 2.3374(1.6407-3.8209) vs 2.0847(1.4755-2.9269);P = 0.0284].There were no significant differences in the GEC or κ between the 2 conditions.CONCLUSION:This study showed that oral sumatriptan significantly delayed gastric emptying of a liquid meal.     

Hyperthyrotropinemia at 2 weeks of age indicates thyroid dysfunction and predicts the occurrence of delayed elevation of thyrotropin in very low birth weight infants

Background For preterm infants, transient hypothyroxinemia of prematurity and transient primary hypothyroidism, especially with delayed elevation of serum thyrotropin (TSH), are important. Methods To address the above two issues, we performed thyrotropin‐releasing hormone (TRH) stimulation tests at about 2 weeks of age for 31 preterm infants with a gestational age of 30 weeks or less. Results For basal TSH levels, 68% of infants (21 of 31) showed normal values (TSH < 10 mU/l) and 32% of infants (10 of 31) showed higher values (four infants: TSH 10–15 mU/l, six infants: TSH > 15 mU/l). Peak TSH values in response to TRH stimulation tests ranged from 9·76 to 114·8 mU/l. All infants showed a significant response to TRH stimulation tests. Only 9·5% of infants (two of 21) with normal basal TSH values showed a hyperresponse (peak TSH > 45 mU/l), whereas 80% of infants (eight of 10) who had higher basal TSH values showed a hyperresponse. All infants who showed mildly elevated basal TSH values (TSH 10–15 mU/l) and a hyperresponse to TRH stimulation tests showed delayed elevation of basal TSH values (TSH > 15 mU/l) later. Conclusions Thyrotropin‐releasing hormone stimulation tests at about 2 weeks of age suggested that the hypothalamic–pituitary–thyroid axis might be established even in extremely premature infants. Basal increased TSH levels (TSH > 10 mU/l) and a hyperresponse to TRH stimulation tests (peak TSH > 45 mU/l) suggested subclinical thyroid dysfunction. Serum TSH values at about 2 weeks of age could be useful for the prediction of delayed TSH elevation.     

Plasma cells and the chronic nonsuppurative destructive cholangitis of primary biliary cirrhosis

There has been increased interest in the role of B cells in the pathogenesis of primary biliary cirrhosis (PBC). Although the vast majority of patients with this disease have anti-mitochondrial antibodies, there is no correlation of anti-mitochondrial antibody titer and/or presence with disease severity. Furthermore, in murine models of PBC, it has been suggested that depletion of B cells may exacerbate biliary pathology. To address this issue, we focused on a detailed phenotypic characterization of mononuclear cell infiltrates surrounding the intrahepatic bile ducts of patients with PBC, primary sclerosing cholangitis, autoimmune hepatitis, chronic hepatitis C, and graft-versus-host disease, including CD3, CD4, CD8, CD20, CD38, and immunoglobulin classes, as well as double immunohistochemical staining for CD38 and IgM. Interestingly, CD20 B lymphocytes, which are a precursor of plasma cells, were found in scattered locations or occasionally forming follicle-like aggregations but were not noted at the proximal location of chronic nonsuppurative destructive cholangitis. In contrast, there was a unique and distinct coronal arrangement of CD38 cells around the intrahepatic ducts in PBC but not controls; the majority of such cells were considered plasma cells based on their expression of intracellular immunoglobulins, including IgM and IgG, but not IgA. Patients with PBC who manifest this unique coronal arrangement were those with significantly higher titers of anti-mitochondrial antibodies. CONCLUSION: These data collectively suggest a role for plasma cells in the specific destruction of intrahepatic bile ducts in PBC and confirm the increasing interest in plasma cells and autoimmunity.     

Complex anatomy surrounding the left atrial posterior wall: analysis with 3D computed tomography

Few studies have explored the topographic anatomy of the esophagus, posterior wall of the left atrium (LA), or fat pads using multidetector computed tomography (MDCT) to prevent the risk of esophageal injury during atrial fibrillation (AF) ablation. MDCT was performed in 110 consecutive patients with paroxysmal or persistent AF before the ablation procedure to understand the anatomic relationship of the esophagus. Two major types of esophagus routes were demonstrated. Leftward (type A) and rightward (type B) routes were found in 90 and 10% of the patients, respectively. A type A route had a larger mean size of the LA than type B. The fat pad was identifiable at the level of the inferior pulmonary vein in 91% of the patients without any predominance of either type. The thickness of the fat pad was thinner in the patients with a dilated LA (>42?mm) than in those with a normal LA size (??42?mm) (p?=?0.01). The results demonstrated that the majority of cases had a leftward route of the esophagus. There was a close association between the LA dilatation and fat pad thinning. With a dilated LA, the esophagus may become easily susceptible to direct thermal injury during AF ablation. Visualization of the anatomic relationship may contribute to the prevention of the potential risk of an esophageal injury.     

Identification of active sites in amidase: Evolutionary relationship between amide bond- and peptide bond-cleaving enzymes

Mainly based on various inhibitor studies previously performed, amidases came to be regarded as sulfhydryl enzymes. Not completely satisfied with this generally accepted interpretation, we performed a series of site-directed mutagenesis studies on one particular amidase of Rhodococcus rhodochrous J1 that was involved in its nitrile metabolism. For these experiments, the recombinant amidase was produced as the inclusion body in Escherichia coli to greatly facilitate its recovery and subsequent purification. With regard to the presumptive active site residue Cys203, a Cys203 → Ala mutant enzyme still retained 11.5% of the original specific activity. In sharp contrast, substitutions in certain other positions in the neighborhood of Cys203 had a far more dramatic effect on the amidase. Glutamic acid substitution of Asp191 reduced the specific activity of the mutant enzyme to 1.33% of the wild-type activity. Furthermore, Asp191 → Asn substitution as well as Ser195 → Ala substitution completely abolished the specific activity. It would thus appear that, among various conserved residues residing within the so-called signature sequence common to all amidases, the real active site residues are Asp191 and Ser195 rather than Cys203. Inasmuch as an amide bond (CO-NH₂) in the amide substrate is not too far structurally removed from a peptide bond (CO-NH-), the signature sequences of various amidases were compared with the active site sequences of various types of proteases. It was found that aspartic acid and serine residues corresponding to Asp191 and Ser195 of the Rhodococcus amidase are present within the active site sequences of aspartic proteinases, thus suggesting the evolutionary relationship between the two.     

Gastrointestinal sounds and migrating motor complex in fasted humans

OBJECTIVE: We investigated the relationships among gastrointestinal sounds, gastrointestinal manometric findings, and small intestinal transit time in healthy fasted humans. METHODS: Gastrointestinal sounds acquired with two microphones attached to the upper and lower abdominal walls of healthy subjects were quantified with a computer-aided sound analysis program. Antroduodenal contractions were recorded by manometry. Small intestinal transit time was measured by breath hydrogen testing after intraduodenal administration of lactulose. RESULTS: The sum of the gastrointestinal sound amplitudes (sound index) in both the upper and lower abdomen changed with time, coinciding with the gastric phases of the migrating motor complex. The sound indices in the upper and lower abdomen were 59.0+/-24.8 and 98.1+/-21.6 mV/min in phase 1, 95.5+/-27.9 and 127.4+/-34.9 mV/min in phase 2, and 132.8+/-12.4 and 188.5+/-73.4 mV/min in phase 3, respectively. There were no significant differences among motility phases in terms of the mean duration or frequency of each sound event. Intravenous erythromycin induced phase 3 in the stomach and doubled the sound index. Somatostatin analogue induced phase-3-like clustered contractions in the duodenum, but inhibited antral contractions and decreased the sound index. The small intestinal transit time was shorter and the sound index increased after intravenous metoclopramide, compared with controls. Scopolamine delayed small intestinal transit time and decreased the sound index. CONCLUSIONS: This study is the first to document the relationships between gastrointestinal sounds and the migrating motor complex. The chronological relation between antral motility and gastrointestinal sounds, and the dissimilar effects of erythromycin and somatostatin, suggest that antral contractions increase gastrointestinal sounds, perhaps by supplying gas into the intestine.     

Superoxide Anion Release Into the Hepatic Sinusoid After an Acute Ethanol Challenge and Its Attenuation by Kupffer Cell Depletion

Superoxide anion release into the hepatic sinusoids and subsequent damage to the endothelial cells of the hepatic sinusoids after ethanol challenge was examined. A 250 mg/kg body weight/hr dose of ethanol was given to rats for 3 hr, and superoxide anion release into the hepatic sinusoids was examined in a liver perfusion model using the cytochrome c method. Ethanol treatment resulted in superoxide anion release into the hepatic sinusoids (0.20 ± 0.01 vs. 0.12 ± 0.02 o.d., p < 0.05) and an increase in the purine nucleoside phosphorylase/alanine aminotransferase ratio in the liver perfusate, a marker of damage to the endothelial cells of the hepatic sinusoids (0.003 ± 0.002 vs. 0.008 ± 0.002; p < 0.05). Tumor necrosis factor-alpha was not detectable in either group, and there were no significant differences in the population of hepatic macrophages, leukocytes, or Kupffer cells between the two groups. To clarify the role of Kupffer cells in the mechanism, 10 mg/kg of body weight of gadolinium chloride was given to rats twice, 24 hr apart, resulting in depletion of ED2-positive cells from the hepatic lobules. The superoxide anion release after the ethanol challenge was significantly attenuated in the Kupffer cell-depleted rats, compared with the controls (0.14 ± 0.02;p <0.05, compared with ethanol alone). The change was associated with a significant decrease in the purine nucleoside phosphorylase/alanine aminotransferase ratio in the liver perfusate (0.004 ± 0.002; p < 0.05, compared with ethanol alone). Ethanol causes superoxide anion release into the hepatic sinusoid and subsequent damage to the sinusoidal endothelial cells. These changes were reduced by Kupffer cell depletion. This supports the view that Kupffer cell depletion has a protective effect on ethanol-induced liver injury.     

Respiratory syncytial virus enhances the expression of CD11b molecules and the generation of superoxide anion by human eosinophils primed with platelet-activating factor

BACKGROUND: Human respiratory syncytial virus (RSV) infection in infancy and early childhood causes acute bronchiolitis and exacerbates bronchial asthma. Eosinophil infiltration may contribute to airway obstruction in RSV infection. OBJECTIVE: We hypothesized that RSV affects eosinophil function. METHODS: Eosinophil activation was evaluated by chemiluminescent detection of superoxide anion (O(2)(-)) generation. Expression of CD11b on eosinophils was determined by flow cytometry. RESULTS: Although RSV did not induce O(2)(-) generation by resting eosinophils, RSV enhanced O(2)(-) generation of eosinophils primed with platelet-activating factor (PAF). Enhancement was significantly inhibited by either continuous agitation to prevent eosinophil adhesion to test tube surfaces or by pretreating cells with anti-CD18 antibody, suggesting that the stimulatory effects of RSV on eosinophils depend on cell adhesion via beta(2)-integrins. In fact, RSV enhanced PAF-induced CD11b expression by eosinophils. CONCLUSIONS These findings suggest that RSV enhances eosinophil CD11b expression and O(2)(-) generation induced by PAF. Thus, RSV infection may exacerbate airway inflammation by enhancing mediator release from eosinophils.