Effect of different types of sugar on gut physiology and microbiota in overfed goose

To explored the difference of goose fatty liver formation induced-by different types of sugar from the intestinal physiology and the gut microflora, an integrated analysis of intestinal physiology and gut microbiota metagenomes was performed using samples collected from the geese including the normal-feeding geese and the overfed geese which were overfed with maize flour or overfeeding dietary supplementation with 10% sugar (glucose, fructose or sucrose, respectively), respectively. The results showed that the foie gras weight of the fructose group and the sucrose group was heavier (P < 0.05) than other groups. Compared with the control group, the ileum weight was significantly higher (P < 0.01), and the cecum weight was significantly lower in the sugar treatment groups (P < 0.001). Compared with the control group, the ratio of villi height to crypt depth in the fructose group was the highest in jejunum (P < 0.05); the trypsin activity of the ileum was higher in the fructose group and the sucrose group (P < 0.05). At the phylum level, Firmicutes, Proteobacteria and Bacteroidetes were the main intestinal flora of geese; and the abundance of Firmicutes in the jejunum was higher in the sugar treatment groups than that of the maize flour group. At the genus level, the abundance of Lactobacillus in the jejunum was higher (P < 0.05) in the sugar treatment groups than that of the maize flour group. In conclusion, forced-feeding diet supplementation with sugar induced stronger digestion and absorption capacity, increased the abundance of Firmicutes and Bacteroidetes and the abundance of Lactobacillus (especially fructose and sucrose) in the gut. So, the fructose and sucrose had higher induction on hepatic steatosis in goose fatty liver formation.

[Application of cloud-based information platform in China National Birth Cohort]

Birth cohort is an important observational study which can continuously and dynamically collect the exposure changes and health outcomes from gametophyte development to adolescence and even old age. However, because of its complex design and difficult implementation, how to construct birth cohort with high quality and high efficiency is the main difficulty faced by epidemiologists at home and abroad. In 2016, China National Birth Cohort was officially launched. The network and information technology were used to explore, and a set of "cloud-based information platform" was established to support this queue construction, containing 16 units in China. After four years of development, the platform has formed a complete set of programs about the construction of cohort information platform, which including recruitment and follow-up management of participants, real-time data interaction, queue quality control, multi-level authority management and function division. The relevant design framework and functional elements provide the references to the future information construction of large-scale birth cohort and even population-based research in China.

Development and Validation of a Natural Language Processing Tool to Identify Patients Treated for Pneumonia across VA Emergency Departments

BACKGROUND

Identifying pneumonia using diagnosis codes alone may be insufficient for research on clinical decision making. Natural language processing (NLP) may enable the inclusion of cases missed by diagnosis codes.

OBJECTIVES

This article (1) develops a NLP tool that identifies the clinical assertion of pneumonia from physician emergency department (ED) notes, and (2) compares classification methods using diagnosis codes versus NLP against a gold standard of manual chart review to identify patients initially treated for pneumonia.

METHODS

Among a national population of ED visits occurring between 2006 and 2012 across the Veterans Affairs health system, we extracted 811 physician documents containing search terms for pneumonia for training, and 100 random documents for validation. Two reviewers annotated span- and document-level classifications of the clinical assertion of pneumonia. An NLP tool using a support vector machine was trained on the enriched documents. We extracted diagnosis codes assigned in the ED and upon hospital discharge and calculated performance characteristics for diagnosis codes, NLP, and NLP plus diagnosis codes against manual review in training and validation sets.

RESULTS

Among the training documents, 51% contained clinical assertions of pneumonia; in the validation set, 9% were classified with pneumonia, of which 100% contained pneumonia search terms. After enriching with search terms, the NLP system alone demonstrated a recall/sensitivity of 0.72 (training) and 0.55 (validation), and a precision/positive predictive value (PPV) of 0.89 (training) and 0.71 (validation). ED-assigned diagnostic codes demonstrated lower recall/sensitivity (0.48 and 0.44) but higher precision/PPV (0.95 in training, 1.0 in validation); the NLP system identified more "possible-treated" cases than diagnostic coding. An approach combining NLP and ED-assigned diagnostic coding classification achieved the best performance (sensitivity 0.89 and PPV 0.80).

CONCLUSION

System-wide application of NLP to clinical text can increase capture of initial diagnostic hypotheses, an important inclusion when studying diagnosis and clinical decision-making under uncertainty.

Gate length scaling effect on high-electron mobility transistors devices using AlGaN/GaN and AlInN/AlN/GaN heterostructures

Compared to AlGaN/GaN HEMT with 0.15 μm T-gate length, the AlInN/AlN/GaN one exhibits much higher current density and transconductance of 1558 mA/mm at Vd = 2 V and 330 mS/mm, respectively. The high extrinsic ft and fmax of 82 GHz and 70 GHz are extracted from AlInN/AlN/GaN HEMT. Besides, we find that the transconductance roll-off is significant in AlGaN/GaN, but largely improved in AlInN/AlN/GaN HEMT, suggesting that the high carrier density and lattice-matched epitaxial heterostructure is important to reach both large RF output power and high operation frequency, especially for an aggressively gate length scaling.

Improvement to functional magnetic resonance imaging (fMRI) methods using non-rigid body image registration methods for correction in the presence of susceptibility artifact effects

Subject head movement, during the experimental and/or clinical procedure is an inevitable part of the functional magnetic resonance imaging (fMRI) brain mapping methods despite the availability of a large variety of head fixation devices employed in these studies. Thus, image registration is an essential processing step in fMRI. This is due to the fact that there is inevitable movement during the course on an fMRI experiment. An additional challenge is the explicit geometrical deformations associated with MRI. It is known that orientational changes are problematic in MRI in the presence of susceptibility differences especially between bone-tissue and air-tissue interfaces. This paper presents two registration strategies for fMRI registration, one using rigid registration based on maximization of mutual information, and the second is non-rigid registration adapted from Thirion's demons algorithm to demonstrate the importance and impact on fMRI in regions of susceptibility and its dependence on the image registration methodology.

A frequent Y chromosome b2/b3 subdeletion shows strong association with male infertility in Han-Chinese population

BACKGROUND

Azoospermia factor c (AZFc) subdeletions were reported to be significant risk factors for spermatogenesis. In this study, we assessed the occurrence of classical AZF deletions and AZFc subdeletions and their impact on male infertility in a Han-Chinese population.

METHODS

This study analysed a population of 699 subjects, including 451 idiopathic infertile patients with a range of fertility disorders and 248 fertile controls, using a retrospective design. Deletions were identified by multiplex PCR.

RESULTS

The prevalence and phenotypes of the classical AZF deletions were similar to previous studies. Subdeletions of the AZFc region in patients showed similar overall frequencies in all sperm concentration categories of gr/gr (7.0%) and b2/b3 (8.9%). For controls, these subdeletions were also found with a prevalence of gr/gr (7.7%) and b2/b3 (3.2%). b1/b3 deletions were not found either in the patients or in the controls.

CONCLUSION

Our data showed a higher frequency of deletion events in this Han-Chinese population than in populations elsewhere in the world. The classical AZF deletions were the primary genetic factors for spermatogenic failure, while no significant association was found for AZFc subdeletions with sperm concentration. However, the b2/b3 subdeletion was significantly associated with idiopathic male infertility (odds ratio, 2.93; 95% confidence interval 1.34-6.39) (P = 0.005), indicating a potential impairment of male fertility.

Automating identification of adverse events related to abnormal lab results using standard vocabularies

Laboratory data need to be imported automatically into central Clinical Study Data Management Systems (CSDMSs), and abnormal laboratory data need to be linked to clinically related adverse events. This import of laboratory data can be automated through mapping to standard vocabularies with HL7/LOINC mapping to the metadata within a CSDMS. We have designed a system that uses the UMLS metathesaurus as a common source to map or link abnormal laboratory values to adverse event CTCAE coded terms and grades in the metadata of TrialDB, a generic CSDMS.

The mouse frizzled 8 receptor is expressed in anterior organizer tissues

Wnt signaling has been shown to be important for axis formation in vertebrates. However, no Wnt ligand or receptor has been shown to be specifically expressed in all the organizer tissues in the mouse embryo. Here we report that the mouse frizzled 8 (mfz8) gene, a Wnt receptor, is expressed in the anterior visceral endoderm (AVE) and the anterior primitive streak, which have been shown to possess organizer activity. mFz8 is also expressed in the descendents of the anterior streak that comprise the anterior mesendoderm (AME) at midgastrulation, with subsequent expression in the anterior neurectoderm, which is specified and patterned by the AVE and AME. Thus, mfz8 is specifically expressed in the organizer tissues that establish the anterior-posterior axis in the mouse embryo.

Pharmacokinetics of desflurane uptake into the brain and body

The aim of this study was to investigate the pharmacokinetics of desflurane uptake into the brain and body by comparing desflurane concentrations in internal jugular-bulb blood (Jdes), arterial blood (Ades) and pulmonary arterial blood (PAdes) at a fixed inspired desflurane concentration. Thirteen patients (aged 42-72 years) undergoing coronary artery bypass grafting surgery were enrolled in this study. They were anaesthetised using a constant 5% inspired desflurane concentration (CIdes) during the first hour of anaesthesia. Under constant volume-controlled ventilation, CIdes and end-tidal desflurane (CEdes) were measured with an infrared analyser. The desflurane concentration in the blood was analysed using gas chromatography, and cardiac output was measured using an Opti-Q pulmonary artery catheter. It took 24 min for the Jdes to equilibrate with Ades. Both CIdes-CEdes and Ades-PAdes gradients persisted during the study period. There was no further uptake of desflurane into the brain after 24 min but there was near-constant uptake into the body.

Pharmacokinetics of sevoflurane uptake into the brain and body

The aim of this study was to investigate the pharmacokinetics of sevoflurane uptake into the brain and body by comparing sevoflurane concentrations in internal jugular-bulb blood (Jsev), arterial blood (Asev) and pulmonary arterial blood (PAsev) over a fixed inspired sevoflurane concentration. Ten patients (aged 51-73 years), undergoing coronary artery bypass grafting surgery were enrolled in this study. They were anaesthetised using a constant 3.5% inspired sevoflurane concentration (CIsev) during the first hour of anaesthesia. During constant volume-controlled ventilation, we measured CIsev and end-tidal sevoflurane (CEsev) using infrared analysis. The sevoflurane concentration in the blood was analysed using gas chromatography, and cardiac output was measured using an Opti-Q pulmonary artery catheter. We found that it took 40 min for the brain concentration to equilibrate with arterial blood (Asev). Both CIsev-CEsev and Asev-PAsev gradients persisted during the study period. There was no further uptake of sevoflurane into the brain after 40 min; however, there was near-constant uptake into the body.

A progressive growing inflammatory pseudotumor of the liver

Inflammatory pseudotumors of the liver are very rare, and their etiology and pathogenesis remain unclear. The diagnosis is often difficult to make because these masses often mimic other lesions such as primary neoplasms, metastases or liver abscesses. Herein, we report a rare case of progressive growing hepatic pseudotumor in a 47-year-old man. The patient presented with body weight loss and general malaise. A series of radiological examinations showed the progressive growth of the hepatic tumor from 3.5 cm to 10.0 cm in diameter within 8 months. He underwent a right lobectomy of the liver, and the final diagnosis was proven by pathology. There were no complications in the post-operative course.

Syntactic priming of nouns and verbs in Chinese

Syntactic priming of Chinese nouns and verbs was investigated in word recognition (cued shadowing of auditory targets) and production (picture naming). Disyllabic compound words were presented after syntactically congruent, incongruent, or neutral auditory contexts, with a zero delay between offset of the context and onset of the target. Significant priming was observed in both tasks, including facilitation as well as inhibition. Post hoc analyses showed that reaction times were also affected by sublexical variables that are especially relevant for Chinese, including syllable density (number of word types and tokens in the language with the same first or second syllable) and semantic transparency (whether the meaning of the whole word is predictable from the separate meanings of the two syllables within the compound). These patterns suggest competitive effects at the sublexical level. Implications for interactive models of lexical access are discussed.

Resection of triple synchronous tumors--gastric adenocarcinoma, gallbladder adenocarcinoma and stromal tumor of the stomach

We herein report a rare case of triple synchronous tumors: gastric adenocarcinoma, gallbladder adenocarcinoma and stromal cell tumor of stomach, which were resected in the same operation. A 72-year-old male patient suffered from poor appetite and epigastric pain that radiated to his back for one month. Upper gastrointestinal endoscopy showed a gastric ulcer measuring 1.5 cm at the prepyloric area, which was proven to be adenocarcinoma by biopsy. A second tumor was found in the gallbladder, measuring 3 cm, by ultrasonography. On computed tomography, a third tumor about 2.5 cm in size was recognized posterior to the gastric high body and anterior to the pancreas. Given the presence of three tumors, he underwent a radical subtotal gastrectomy with Billroth-II gastrojejunostomy and simultaneous cholecystectomy. Pathological findings revealed gastric adenocarcinoma, gallbladder adenocarcinoma and stromal cell tumor of the stomach. The postoperative course was smooth.

From fertilization to gastrulation: axis formation in the mouse embryo

Although much remains unknown about how the embryonic axis is laid down in the mouse, it is now clear that reciprocal interactions between the extraembryonic and embryonic lineages establish and reinforce patterning of the embryo. At early post-implantation stages, the extraembryonic ectoderm appears to impart proximal-posterior identity to the adjacent proximal epiblast, whereas the distal visceral endoderm signals to the underlying epiblast to restrict posterior identity as it moves anteriorward. At gastrulation, the visceral endoderm is necessary for specifying anterior primitive streak derivatives, which, in turn, pattern the anterior epiblast. Polarity of these extraembryonic tissues can be traced back to the blastocyst stage, where asymmetry has been linked to the point of sperm entry at fertilization.

Nodal signalling in the epiblast patterns the early mouse embryo

Shortly after implantation the mouse embryo comprises three tissue layers. The founder tissue of the embryo proper, the epiblast, forms a radially symmetric cup of epithelial cells that grows in close apposition to the extra-embryonic ectoderm and the visceral endoderm. This simple cylindrical structure exhibits a distinct molecular pattern along its proximal-distal axis. The anterior-posterior axis of the embryo is positioned later by coordinated cell movements that rotate the pre-existing proximal-distal axis. The transforming growth factor-beta family member Nodal is known to be required for formation of the anterior-posterior axis. Here we show that signals from the epiblast are responsible for the initiation of proximal-distal polarity. Nodal acts to promote posterior cell fates in the epiblast and to maintain molecular pattern in the adjacent extra-embryonic ectoderm. Both of these functions are independent of Smad2. Moreover, Nodal signals from the epiblast also pattern the visceral endoderm by activating the Smad2-dependent pathway required for specification of anterior identity in overlying epiblast cells. Our experiments show that proximal-distal and subsequent anterior-posterior polarity of the pregastrulation embryo result from reciprocal cell-cell interactions between the epiblast and the two extra-embryonic tissues.

Prognostic factors of hyperglycemic hyperosmolar nonketotic state

BACKGROUND

To delineate the prognostic factors of patients suffering from hyperglycemic hyperosmolar nonketotic state (HHNK) in Taiwan.

METHODS

We reviewed the charts of patients who had been admitted to the Division of Endocrinology and Metabolism of Kaohsiung Veterans General Hospital from 1992 to 1998 due to HHNK. General and clinical data were collected. The influential factors for prognosis were determined.

RESULTS

One hundred and nineteen patients fulfilling the criteria of HHNK were included in our study. The mean age was 67.8 +/- 11.7 years with male predominance. Twenty-nine patients died which produced a fatality rate of 24.4%. Eighty-six (72.3%) cases occurred in patients with known diabetic history, while another thirty-three (27.7%) occurred in patients with no diabetic history. Most patients received oral antidiabetic drugs before HHNK episodes. The patients who died had shorter length of inpatient stay than did survivors. The leading precipitating factor was infection (57.1%), followed by poor compliance of medication (21.0%) and undiagnosed diabetes (10.9%). Fifty patients (42%) had a history of stroke. The risk factors for death included precipitation of HHNK by infection and low Glasgow coma scale (GCS) on admission. Old age itself did not contribute to death. Severity of hyperglycemia or hyperosmolarity was also not an important prognostic factor. Multiple logistic regression revealed that low GCS on admission was the most influential factor of leading to death. Most of the patients who died did so due to underlying precipitating factors.

CONCLUSIONS

Neither age nor osmolarity, but underlying precipitating factors and state of consciousness were the most influential factors affecting the prognosis of HHNK.

Prevalence and significance of hepatitis B virus (HBV) pre-S mutants in serum and liver at different replicative stages of chronic HBV infection

Several types of naturally occurring pre-S mutants in sera or liver tissues in patients with chronic hepatitis B virus (HBV) infection have been identified. To clarify the prevalence and significance of emergence of pre-S mutants, 140 sera and 18 resected livers from patients with HBV were studied. Replicative status was designated as high, intermediate, and low based on the HBV-DNA levels in serum or the expression of HBV antigens in liver. In vitro transfection and Western blot analysis were performed to characterize expression and secretion of HBsAg by the mutant constructs. Five major types (I to V) of pre-S deletion mutants in serum and liver and 2 types (VI and VII) in liver were identified. Pre-S mutant was 6.4% at high replicative phase, 13% at intermediate, and 37.5% at low or nonreplicative phases in serum. In livers, the same tendency existed: pre-S2 deletion mutants emerged and prevailed at a low replicative phase in hepatocytes that expressed a novel marginal pattern of HBsAg and usually clustered in groups. The deletion sequence of pre-S2 region coincides with human leukocyte antigen-restricted T- and B-cell epitopes. In vitro HBsAg was retained in the hepatocytes and synthesis and secretion of major surface antigen decreased for most of the pre-S mutants. Pre-S mutants prevailed with evolution of chronic HBV, probably under immune pressure. Emergence of pre-S mutants may account for the life-long persistence and discrepancy of HBsAg in serum and liver in HBV and may confer growth advantage in view of the clustering proliferation of hepatocytes harboring pre-S2 mutant.

Extracellular mutations of protease-activated receptor-1 result in differential activation by thrombin and thrombin receptor agonist peptide

The protease-activated thrombin receptor-1 (PAR-1) can be activated by both the tethered ligand exposed by thrombin cleavage and a synthetic peptide having the tethered ligand sequence (thrombin receptor agonist peptide or TRAP). We conducted a mutational analysis of extracellular residues of the receptor potentially involved in interaction with both the tethered ligand and the soluble peptide agonist. Agonist-stimulated calcium efflux in X. laevis oocytes or inositol phosphate accumulation in COS-7 cells was used to assess receptor activation. We have also examined the binding of a radiolabeled TRAP for the wild-type and mutant PAR-1 receptors. Our results indicated that most of the mutations strongly affected TRAP-induced responses without significantly altering thrombin-induced responses or TRAP binding. Several point mutations and deletion of extracellular domains (DeltaEC3, DeltaNH3) drastically altered the ability of mutant receptors to respond to TRAP, but not to thrombin, and did not affect the affinity for the radiolabeled TRAP by these mutant receptors. Only mutations that disrupted the putative disulfide bond or substitution of multiple acidic residues in the second extracellular loop by alanine had a significant effect on both ligand binding and thrombin activation. These results suggest that although both agonists can activate PAR-1, there are profound differences in the ability of thrombin and TRAP to activate PAR-1. In addition, we have found PAR-1 mutants with the ability to dissociate receptor-specific binding from functional activity.

Disturbed small intestinal motility in the late rat pregnancy

We investigated whether various periods of pregnancy might disturb rat gastrointestinal motility. When the proestrus of female rats occurred, they were housed with male rats. Motility studies were conducted on day 7 (first period), day 14 (second) and day 21 (third) of pregnancy, respectively. After the orogastric feeding of radiochromium marker, rats were sacrificed 15 min later. Gastric emptyings of pregnant rats measured at various periods did not differ from the nonpregnant diestrus controls. The geometric center represented intestinal transits in the first, second and third periods of pregnancy and controls were (mean+/-SEM) 4.54+/-0.25, 4.47+/-0.17, 3.61+/-0.27 and 4.98+/-0.13, respectively (p < 0.01) while their plasma progesterone levels were 15.6+/-2.6, 18+/-1.4, 7.1+/-0.5 and 8.6+/-0.4 ng/ml, respectively (p< 0.01). This shows that late pregnancy inhibits small intestinal transit, whereas gastric emptying remains unchanged. Altered progesterone during pregnancy is not a main mediator to disturb intestinal transit.

An on-line quantitative immunoassay system based on a quartz crystal microbalance

We have established a QCM immunoassay system which allows on-line and quantitative monitoring throughout the entire detection procedure and provides information on the surface coverage and the binding ratio of antibody to antigen. Compared to conventional immunoassay systems the QCM system offers advantages of short response times, obviates the need for additive labeling reagents, and permits direct conversion of a frequency signal into mass accumulation.

Identification of a pre-S2 mutant in hepatocytes expressing a novel marginal pattern of surface antigen in advanced diseases of chronic hepatitis B virus infection

BACKGROUND AND AIMS

The expression of hepatitis B viral (HBV) antigens in liver tissue reflects the replicative status of chronic HBV infection. We have previously recognized a novel marginal pattern of hepatitis B surface antigen (HBsAg) in hepatocytes, which usually clusters in groups and emerges at the late non-replicative phase. This study was designed to investigate whether the marginal-type HBsAg represented the gene product of a specific HBV-surface mutant.

METHODS

Microdissection of cirrhotic nodules homogeneously expressing marginal HBsAg was performed on two of 12 resected livers from HBsAg-seropositive patients with hepatocellular carcinoma. The gene presumably encoding marginal HBsAg was polymerase chain reaction (PCR)-cloned, sequenced and analysed. In vitro transfection and expression of the cloned surface mutant plasmids were performed on the Huh7 cell line to illustrate intrahepatic HBsAg expression.

RESULTS

Immunohistochemical staining revealed that the marginal HBsAg was positive for pre-S1 and thus contained large surface proteins. The PCR cloning and sequencing of the genes presumably encoding marginal-type HBsAg in both cases revealed the same deletion at the 5' terminus (nt 2-55) of pre-S2. A point mutation on the small-surface (S) antigen was also found in one case. The pre-S2 deletion sequence and the mutation sites of the S gene coincide with human lymphocyte antigen-restricted T- and/or B-cell epitopes. In vitro transfection of the mutant plasmid revealed a blot-like retention or accumulation of HBsAg in the cytoplasm or at the periphery of hepatocytes, accompanied by a decreased secretion of HBsAg in the culture supernatant, mimicking intrahepatic expression.

CONCLUSION

A natural pre-S2 deletion mutant was identified in hepatocytes expressing a novel marginal pattern of HBsAg, which probably contains mutant, large, surface proteins. The biological significance of the pre-S2 deletion mutant should be interesting in view of the clustering proliferation of hepatocytes expressing marginal HBsAg.

Do phosphatidylinositides modulate vertebrate phototransduction?

Mammalian rod cyclic nucleotide gated (CNG) channels (i.e., alpha plus beta subunits) are strongly inhibited by phosphatidylinositol 4, 5-bisphosphate (PIP(2)) when they are expressed in Xenopus oocytes and studied in giant membrane patches. Cytoplasmic Mg-ATP inhibits CNG currents similarly, and monoclonal antibodies to PIP(2) reverse the effect and hyperactivate currents. When alpha subunits are expressed alone, PIP(2) inhibition is less strong; olfactory CNG channels are not inhibited. In giant patches from rod outer segments, inhibition by PIP(2) is intermediate. Other anionic lipids (e.g., phosphatidyl serine and phosphatidic acid), a phosphatidylinositol-specific phospholipase C, and full-length diacylglycerol have stimulatory effects. Although ATP also potently inhibits cGMP-activated currents in rod patches, the following findings indicate that ATP is used to transphosphorylate GMP, generated from cGMP, to GTP. First, a phosphodiesterase (PDE) inhibitor, Zaprinast, blocks inhibition by ATP. Second, inhibition can be rapidly reversed by exogenous regulator of G-protein signaling 9, suggesting G-protein activation by ATP. Third, the reversal of ATP effects is greatly slowed when cyclic inosine 5'-monophosphate is used to activate currents, as expected for slow inosine 5' triphosphate hydrolysis by G-proteins. Still, other results remain suggestive of regulatory roles for PIP(2). First, the cGMP concentration producing half-maximal CNG channel activity (K(1/2)) is decreased by PIP(2) antibody in the presence of PDE inhibitors. Second, the activation of PDE activity by several nucleotides, monitored electrophysiologically and biochemically, is reversed by PIP(2) antibody. Third, exogenous PIP(2) can enhance PDE activation by nucleotides.

Secular trends of HBeAg prevalence among HBsAg-positive delivery mothers in a hepatitis B endemic area

A high prevalence of HBeAg among HBsAg-positive mothers at the time of delivery results in a high prevalence of hepatitis B vertical transmission. From 1990 to 1995, 896 pregnant HBsAg-positive women, including 411 (46 per cent) HBeAg-positive subjects, were enrolled in our study to analyse the secular change in HBeAg prevalence. Their mean age, number of pregnancies and parity were 29.5 +/- 4.1 years, 2.0 +/- 1.2, and 0.6 +/- 0.7, respectively. The prevalence rates of HBeAg were 48, 54, 49, 47, 40, and 40 per cent among the subjects enrolled in 1990, 1991, 1992, 1993, 1994, and 1995, respectively. In univariate analyses, prevalence of HBeAg decreased by the calendar year of pregnancy (p = 0.01), and also by age (p < 0.00001), number of pregnancies (p < 0.0001) and parity (p < 0.0002). After adjusting for age in multiple logistic regression, the calendar year of pregnancy was still the independent variable, while gravida and parity became insignificant. The odd ratios (95 per cent confidence interval) of HBeAg negative-seroconversion in the equations were 1.09 (1.00-1.19) per calendar year and 1.14 (1.10-1.18) per year of age. Our results have shown a secular decrease in HBeAg-prevalence among pregnant HBsAg-positive women in Taiwan.

Age-related differences in the secretion of calcitonin in male rats

The mechanism of hypercalcitoninemia associated with aging was investigated in male rats. To mimic some of the hormonal changes with aging, orchidectomized (Orch) and hyperprolactinemic rats were used to mimic the physiological status of aging. Orch and haloperidol-induced hyperprolactinemic rats aged 3, 8, and 17 months were infused with CaCl2 and then bled from a jugular catheter following the CaCl2 challenge. Rat thyroid gland was incubated with Locke's medium at 37 degrees C for 30 minutes. Compared with 8- and 3-month-old rats, 17-month-old rats exhibited the lowest levels of plasma testosterone and the highest levels of plasma prolactin (PRL) and calcitonin (CT). The release of CT in the thyroid glands in vitro was highest in 17-month-old rats. Orchidectomy decreased rat plasma CT and thyroid CT release in vitro. Hyperprolactinemic rats had higher levels of plasma PRL and CT compared with control animals. The release of thyroid CT in vitro was greater in hyperprolactinemic rats. These results suggest that the hypersecretion of CT in 17-month-old rats may be due in part to hyperprolactinemia.

Acute respiratory distress syndrome following cutaneous exposure to Lysol: a case report

Lysol (mixed cresols) is a brand of popular detergent commonly used to disinfect toilets and floors in Taiwan. We report a patient with acute respiratory failure immediately following chemical burns caused by skin contact with Lysol solution. On admission, chest radiography showed bilateral diffuse pulmonary infiltrates and an arterial blood gas analysis disclosed hypoxemia refractory to a high concentration of oxygen by inhalation. Under the impression of acute respiratory distress syndrome, our patient was admitted to the intensive care unit for respiratory care. Poor clinical improvement was noted, despite aggressive respiratory therapy. High-dose steroid therapy (hydrocortisone 30 mg/kg/day) was administered from the seventh day after mechanical ventilation began and the ratio of arterial partial pressure of oxygen to fractional concentration of oxygen in inspired gas improved thereafter. The amount of steroid was gradually tapered to the maintenance dose and the patient was successfully weaned from the ventilator after a 93-day course of mechanical ventilation.

Thrombocytosis in children at one medical center of southern Taiwan

Thrombocytosis in children is common, but usually without symptoms. The causes of thrombocytosis in children are considered to be mostly due to infection, trauma, surgery, blood disease, prematurity, renal disease and chronic inflammation. To evaluate the incidence and etiology of thrombocytosis of the hospitalized patients, patients who were admitted to the Pediatric Department of Kaohsiung Medical College Hospital (KMCH) from October 1996 to November 1997 were studied. There were 2910 cases studied and 220 cases (127 male and 93 female) had thrombocytosis (> or = 500 x 10(9)/L) with a rate of 7.6%. The causes of thrombocytosis are infections (49.5%), Kawasaki disease (6.4%), postsplenectomy (7.8%), blood diseases (3.7%), malignancies (3.2%), renal disorders (3.2%), prematurity (3.2%), tissue damage (4.5%), chronic inflammation (1.8%), recovery from marrow suppression (1.3%), immunologic disturbances (2.2%), essential thrombocythemia (0.5%), and miscellaneous factors (3.7%). Thrombocytosis associated with multiple, simultaneous causative factors was found in 9.0% of these cases. Thrombocytosis secondary to infectious diseases or Kawasaki disease was significantly more common in children under 2 years old. The most commonly associated infectious disease was respiratory tract infection (61.1%). There were 29 children (13.2%) presenting a platelet count of more than 800,000/mm3. However, no thrombotic complications were seen in any of the children. By far, the major cause of thrombocytosis in our cases was reactive in character. Most of the thrombocytosis cases were due to infections, inflammatory diseases, or Kawasaki disease.

GAT1 (GABA:Na+:Cl-) cotransport function. Steady state studies in giant Xenopus oocyte membrane patches

Neurotransmitter transporters are reported to mediate transmembrane ion movements that are poorly coupled to neurotransmitter transport and to exhibit complex "channel-like" behaviors that challenge the classical "alternating access" transport model. To test alternative models, and to develop an improved model for the Na+- and Cl--dependent gamma-aminobutyric acid (GABA) transporter, GAT1, we expressed GAT1 in Xenopus oocytes and analyzed its function in detail in giant membrane patches. We detected no Na+- or Cl--dependent currents in the absence of GABA, nor did we detect activating effects of substrates added to the trans side. Outward GAT1 current ("reverse" transport mode) requires the presence of all three substrates on the cytoplasmic side. Inward GAT1 current ("forward" transport mode) can be partially activated by GABA and Na+ on the extracellular (pipette) side in the nominal absence of Cl-. With all three substrates on both membrane sides, reversal potentials defined with specific GAT1 inhibitors are consistent with the proposed stoichiometry of 1GABA:2Na+:1Cl-. As predicted for the "alternating access" model, addition of a substrate to the trans side (120 mM extracellular Na+) decreases the half-maximal concentration for activation of current by a substrate on the cis side (cytoplasmic GABA). In the presence of extracellular Na+, the half-maximal cytoplasmic GABA concentration is increased by decreasing cytoplasmic Cl-. In the absence of extracellular Na+, half-maximal cytoplasmic substrate concentrations (8 mM Cl-, 2 mM GABA, 60 mM Na+) do not change when cosubstrate concentrations are reduced, with the exception that reducing cytoplasmic Cl- increases the half-maximal cytoplasmic Na+ concentration. The forward GAT1 current (i.e., inward current with all extracellular substrates present) is inhibited monotonically by cytoplasmic Cl- (Ki, 8 mM); cytoplasmic Na+ and cytoplasmic GABA are without effect in the absence of cytoplasmic Cl-. In the absence of extracellular Na+, current-voltage relations for reverse transport current (i.e., outward current with all cytoplasmic substrates present) can be approximated by shallow exponential functions whose slopes are consistent with rate-limiting steps moving 0.15-0.3 equivalent charges. The slopes of current-voltage relations change only little when current is reduced four- to eightfold by lowering each cosubstrate concentration; they increase twofold upon addition of 100 mM Na+ to the extracellular (pipette) side.

GAT1 (GABA:Na+:Cl-) cotransport function. Database reconstruction with an alternating access model

We have developed an alternating access transport model that accounts well for GAT1 (GABA:Na+:Cl-) cotransport function in Xenopus oocyte membranes. To do so, many alternative models were fitted to a database on GAT1 function, and discrepancies were analyzed. The model assumes that GAT1 exists predominantly in two states, Ein and E(out). In the Ein state, one chloride and two sodium ions can bind sequentially from the cytoplasmic side. In the Eout state, one sodium ion is occluded within the transporter, and one chloride, one sodium, and one gamma-aminobutyric acid (GABA) molecule can bind from the extracellular side. When Ein sites are empty, a transition to the Eout state opens binding sites to the outside and occludes one extracellular sodium ion. This conformational change is the major electrogenic GAT1 reaction, and it rate-limits forward transport (i.e., GABA uptake) at 0 mV. From the Eout state, one GABA can be translocated with one sodium ion to the cytoplasmic side, thereby forming the *Ein state. Thereafter, an extracellular chloride ion can be translocated and the occluded sodium ion released to the cytoplasm, which returns the transporter to the Ein state. GABA-GABA exchange can occur in the absence of extracellular chloride, but a chloride ion must be transported to complete a forward transport cycle. In the reverse transport cycle, one cytoplasmic chloride ion binds first to the Ein state, followed by two sodium ions. One chloride ion and one sodium ion are occluded together, and thereafter the second sodium ion and GABA are occluded and translocated. The weak voltage dependence of these reactions determines the slopes of outward current-voltage relations. Experimental results that are simulated accurately include (a) all current-voltage relations, (b) all substrate dependencies described to date, (c) cis-cis and cis-trans substrate interactions, (d) charge movements in the absence of transport current, (e) dependencies of charge movement kinetics on substrate concentrations, (f) pre-steady state current transients in the presence of substrates, (g) substrate-induced capacitance changes, (h) GABA-GABA exchange, and (i) the existence of inward transport current and GABA-GABA exchange in the nominal absence of extracellular chloride.

GAT1 (GABA:Na+:Cl-) cotransport function. Kinetic studies in giant Xenopus oocyte membrane patches

To explain cotransport function, the "alternating access" model requires that conformational changes of the empty transporter allow substrates to bind alternatively on opposite membrane sides. To test this principle for the GAT1 (GABA:Na+:Cl-) cotransporter, we have analyzed how its charge-moving partial reactions depend on substrates on both membrane sides in giant Xenopus oocyte membrane patches. (a) "Slow" charge movements, which require extracellular Na+ and probably reflect occlusion of Na+ by GAT1, were defined in three ways with similar results: by application of the high-affinity GAT1 blocker (NO-711), by application of a high concentration (120 mM) of cytoplasmic Cl-, and by removal of extracellular Na+ via pipette perfusion. (b) Three results indicate that cytoplasmic Cl- and extracellular Na+ bind to the transporter in a mutually exclusive fashion: first, cytoplasmic Cl- (5-140 mM) shifts the voltage dependence of the slow charge movement to more negative potentials, specifically by slowing its "forward" rate (i.e., extracellular Na+ occlusion); second, rapid application of cytoplasmic Cl- induces an outward current transient that requires extracellular Na+, consistent with extracellular Na+ being forced out of its binding site; third, fast charge-moving reactions, which can be monitored as a capacitance, are "immobilized" both by cytoplasmic Cl- binding and by extracellular Na+ occlusion (i.e., by the slow charge movement). (c) In the absence of extracellular Na+, three fast (submillisecond) charge movements have been identified, but no slow components. The addition of cytoplasmic Cl- suppresses two components (tau < 1 ms and 13 micros) and enables a faster component (tau < 1 micros). (d) We failed to identify charge movements of fully loaded GAT1 transporters (i.e., with all substrates on both sides). (e) Under zero-trans conditions, inward (forward) GAT1 current shows pronounced pre-steady state transients, while outward (reverse) GAT1 current does not. (f) Turnover rates for reverse GAT1 transport (33 degrees C), calculated from the ratio of steady state current magnitude to total charge movement magnitude, can exceed 60 s(-1) at positive potentials.

Expression and characterization of elastase inhibitors from the ascarid nematodes Anisakis simplex and Ascaris suum

Two elastase inhibitors, ASPI-1 and ASPI-2, from the parasitic nematode Anisakis simplex, have been isolated and characterized. Because these inhibitors are similar in size (60 amino acids in length) and primary sequence (52 and 47% identical) to the Ascaris suum chymotrypsin/elastase inhibitor-1 (AsC/E-1), we suggest that these Anisakis elastase inhibitors belong to the same unique class of canonical inhibitors formed by the family of Ascaris inhibitors (Huang K, Strynadka NCJ, Bernard VD, Peanasky RJ, James MG. Structure 1994;2:679-689). To compare ASPI-1 with AsC/E-1, we expressed both inhibitors in Pichia pastoris and found that: (1) the association constant of rASPI-1 with porcine pancreatic elastase (PPE) is similar to native inhibitor (Ka = 4.5 x 10(9) and 6.4 x 10(9) M(-1), respectively); (2) rASPI-1 is a potent inhibitor of PPE and human leukocyte elastase (Ka = 1.6 x 10(9) M(-1)); and (3) it is only a very weak inhibitor of chymotrypsin (CHYM) (Ka = 1.2 x 10(6) M(-1)). In contrast to the Anisakis inhibitor, however, rAsC/E inhibitor-1 is a very strong inhibitor of both PPE (Ka = 3.5 x 10(10) M(-1)) and CHYM (Ka = 3.6 x 10(12) M(-1)). We also found that the determined reactive sites (P1-P'1) of rASPI-1 and rAsC/E-1, as recognized by PPE, are Ala 28-Met 29 and Leu 31-Met 32, respectively. These P1-P'1 residues of AsC/E-1 constitute the same reactive site as that also recognized by CHYM (Peanasky RJ, Bentz Y, Homandberg GA, Minor ST, Babin DR. Arch Biochem Biophys 1994;232:135-142). The difference in specificities of ASPI-1 and AsC/E-1 toward their cognate serine proteases may be attributed to the P1 and P'3 residues in the inhibitors. Elastase, which recognizes both alanine and leucine, canaccommodate both ascarid inhibitors, whereas chymotrypsin, which prefers bulky, hydrophobic residues, only recognizes the Ascaris C/E inhibitor-1.

Inhibition of salmon calcitonin on secretion of progesterone and GnRH-stimulated pituitary luteinizing hormone

The effects of salmon calcitonin (sCT) on the production of progesterone and secretion of luteinizing hormone (LH) were examined in female rats. Diestrous rats were intravenously injected with saline, sCT, human chorionic gonadotropin (hCG), or hCG plus sCT. Ovariectomized (Ovx) rats were injected with saline or sCT. In the in vitro experiments, granulosa cells and anterior pituitary glands (APs) were incubated with the tested drugs. Plasma LH levels of Ovx rats were reduced by sCT injection. Administration of sCT decreased the basal and hCG-stimulated progesterone release in vivo and in vitro. 8-Bromo-cAMP dose dependently increased progesterone production but did not alter the inhibitory effect of sCT. H-89 did not potentiate the inhibitory effect of sCT. Higher doses of 25-hydroxycholesterol and pregnenolone stimulated progesterone production and diminished the inhibitory effects of sCT. sCT did not decrease basal release of LH by APs, but pretreatment of sCT decreased gonadotropin-releasing hormone (GnRH)-stimulated LH secretion. These results suggested that sCT inhibits progesterone production in rats by preventing the stimulatory effect of GnRH on LH release in rat APs and acting directly on ovarian granulosa cells to decrease the activities of post-cAMP pathway and steroidogenic enzymes.

Regulation of testosterone secretion by prolactin in male rats

The goal of this study was to characterize the mechanism by which hyperprolactinemia alters testosterone production in rat testicular interstitial cells (TICs). Hyperprolactinemia was induced by grafting 2 anterior pituitary (AP) glands under the subcapsular space of the kidney in experimental rats. Control rats were grafted with brain cortex (CX). Six weeks post-grafting, rats were challenged with human chorionic gonadotropin (hCG) then, the changes in either plasma testosterone or luteinizing hormone was measured. Additionally, TICs were isolated and challenged in vitro with hCG or prolactin, and the testosterone release measured by radioimmunoassay. Further investigation in signal transduction as intracellular 3':5' cyclic adenosine monophosphate (cAMP) production was observed under a regulation of forskolin or SQ22536. After the challenge of hCG or GnRH, the AP-grafted rats showed a suppressed response in testosterone release as compared to those in the CX-grafted group. The in vitro data from the AP-grafted rats compared to the CX-grafted animals showed a diminished response in testosterone release upon hCG stimulation. Administration of forskolin or SQ22536 disclosed dysfunction of adenylate cyclase in TICs from the AP-grafted rats. When 8-Br-cAMP was incubated with TICs, the testosterone production was lower in the AP-grafted compared to the CX-grafted group. These results suggest that in addition to adenylate cyclase dysfunction, inefficiency of post-cAMP pathways are also involved in the hypogonadism elicited by hyperprolactinemia in rats.

Regulation of thyroid hormones on the production of testosterone in rats

The effects of a thyroidectomy and thyroxine (T4) replacement on the spontaneous and human chorionic gonadotropin (hCG)-stimulated secretion of testosterone and the production of adenosine 3',5'-cyclic monophosphate (cAMP) in rat testes were studied. Thyroidectomy decreased the basal levels of plasma luteinizing hormone (LH) and testosterone, which delayed the maximal response of testosterone to gonadotropin-releasing hormone (GnRH) and hCG in male rats. T4 replacement in thyroparathyroidectomized (Tx) rats restored the concentrations of plasma LH and testosterone to euthyroid levels. Thyroidectomy decreased the basal release of hypothalamic GnRH, pituitary LH, and testicular testosterone as well as the LH response to GnRH and testosterone response to hCG in vitro. T4 replacement in Tx rats restored the in vitro release of GnRH, GnRH-stimulated LH release as well as hCG-stimulated testosterone release. Administration of T4 in vitro restored the release of testosterone by rat testicular interstitial cells (TICs). The increase of testosterone release in response to forskolin and androstenedione was less in TICs from Tx rats than in that from sham Tx rats. Administration of nifedipine in vitro resulted in a decrease of testosterone release by TICs from sham Tx but not from Tx rats. The basal level of cAMP in TICs was decreased by thyroidectomy. The increased accumulation of cAMP in TICs following administration of forskolin was eliminated in Tx rats. T4 replacement in Tx restored the testosterone response to forskolin. But the testosterone response to androstenedione and the cAMP response to forskolin in TICs was not restored by T4 in Tx rats. These results suggest that the inhibitory effect of a thyroidectomy on the production of testosterone in rat TICs is in part due to: 1) the decreased basal secretion of pituitary LH and its response to GnRH; 2) the decreased response of TICs to gonadotropin; and 3) the diminished production of cAMP, influx of calcium, and activity of 17beta-HSD. T4 may enhance testosterone production by acting directly at the testicular interstitial cells of Tx rats.

Comparison of immunogenicity of simultaneous and nonsimultaneous vaccination with MMR and JE vaccine among 15-month-old children

To evaluate the immunogenicity of measles- mumps- rubella (MMR) vaccination with Japanese encephalitis (JE) vaccine nonsimultaneously and simultaneously, 145 babies, aged 15 months were enrolled into two groups. Group A received MMR and JE vaccines nonsimultaneously at an interval of 6 weeks; group B received the vaccinations simultaneously. Antibody titers of MMR and JE were detected before and 8 weeks after vaccination. A total of 118 babies (61 in group A; 57 in group B) completed the study. In group A, mean increments of logarithmic geometric mean titers (GMTs) of MMR and JE were 4.51, 5.93, 4.07 and 1.99; seroresponse rates were 100% (61/61), 77.05% (47/61), 96.72% (59/61) and 59.02% (36/61) respectively. In group B, mean increments of logarithmic GMTs of MMR and JE were 4.35, 5.37, 4.44 and 1.93; seroresponse rates were 98.25% (56/57), 77.19% (44/57), 98.25% (56/57) and 57.89% (33/57) respectively. There were no significant differences between these two groups. These results suggest that simultaneous and nonsimultaneous vaccination with MMR and JE vaccines were similar in immunogenicity.

Effects of estradiol on aldosterone secretion in ovariectomized rats

The effects and action mechanisms of estradiol on aldosterone secretion in female rats were studied. Replacement of estradiol benzoate (EB) increased the levels of plasma estradiol and aldosterone in ovariectomized (Ovx) rats. The aldosterone release from zona glomerulosa (ZG) cells was higher in EB-treated rats than in oil-treated animals. EB treatment potentiated the responses of aldosterone release to adrenocorticotropic hormone (ACTH), forskolin (FSK), and 8-bromoadenosine 3',5'-cyclic monophosphate (8-Br-cAMP). Administration of EB in vivo did not alter cAMP production in response to ACTH or FSK. Although angiotensin II (Ang II) increased aldosterone secretion by rat ZG cells, the stimulatory effect of Ang II on the release of aldosterone was not altered by EB treatment. The conversions of [3H]-deoxycorticosterone to [3H]-corticosterone and [3H]-corticosterone to [3H]-aldosterone in EB-treated groups were greater than those in the oil-treated group. These results suggest that estradiol increases aldosterone secretion in part through the mechanisms involving the activation of the post-cAMP pathway, 11beta-hydroxylase and aldosterone synthase activity.

Effects of hyperprolactinemia on calcitonin secretion in male rats

The role of prolactin (PRL) in calcitonin (CT) release by the thyroid C cell in male rats was studied. Anterior pituitary (AP)-grafted male rats were characterized by hyperprolactinemia. Brain cortex (CX)-grafted male rats were used as control animals. AP- and CX-grafted rats were infused intravenously with CaCl2 and bled from the jugular catheter at 0, 30, 60, and 120 minutes following the CaCl2 challenge. Rat thyroid gland was incubated with or without 3-isobutyl-1-methylxanthine (IBMX) at 37 degrees C for 30 minutes. Thyroid C cells were incubated in culture medium at 37 degrees C for 60 minutes. Cyclic adenosine 3',5'-monophosphate (cAMP) in rat thyroid tissues following incubation with IBMX was extracted by 65% ethanol. AP-grafted rats had higher plasma levels of PRL and CT compared with CX-grafted rats. Both the release of CT and accumulation of cAMP in thyroid glands were higher in AP-grafted versus CX-grafted rats. Direct administration of ovine PRL (oPRL) on the thyroid glands did not increase CT secretion in vitro. Thyroid C cells of AP-grafted rats secreted more CT compared with CX-grafted rat cells. These results suggest that hyperprolactinemia increases the release of CT by thyroid C cells in rats through a cAMP-dependent pathway caused by an indirect effect of PRL.

An ultra-high common-mode rejection ratio (CMRR) AC instrumentation amplifier for laplacian electrocardiographic measurement

Laplacian electrocardiograms (LECGs) localize the moment of activation (MOA) of the heart noninvasively at a nearby point on the chest surface. Tripolar concentric ring (TCR) electrodes provide small, but well-defined, site-specific second spatial derivative signals of the potential on the chest surface for studying the activation sequence of the myocardium. A battery-powered, modified AC instrumentation amplifier (IA) was used as preamplifier to obtain signals with a high common-mode rejection ratio (CMRR). The authors' direct-coupled quasi-high-pass IA has high input impedance and high CMRR, without the need to match capacitors and resistors. The amplifier circuit and two lithium cells were integrated with the substrate for the TCR sensor to minimize inductive pickup by the leads. Combining the natural ability of the TCR electrodes to reject common-mode signals with the high CMRR of the IA made it possible to obtain LECG signals in real time with good signal-to-noise ratio (SNR). The authors observed and recorded the MOAs from 16 sites in a 4-by-4 matrix from the left side of the thorax of each subject. Beat-by-beat changes were observed from one subject showing episodes of bigeminal rhythm. The authors were able to obtain localized signals representing the right and left ventricles from surface TCR electrodes in real time.

Increase of thyrotropin response to thyrotropin-releasing hormone (TRH) and TRH release in rats during pregnancy

Regulation of thyrotropin (TSH) release by thyrotropin releasing hormone (TRH) in the anterior pituitary gland (AP) of pregnant rats was studied. The pregnant (day 7, 14, and 21) and diestrous rats were decapitated. AP was divided into 2 halves, and then incubated with Locke's solution at 37 degrees C for 30 min following a preincubation. After replacing with media, APs were incubated with Locke's solution containing 0, or 10 nM TRH for 30 min. Both basal and TRH-stimulated media were collected at the end of incubation. Medial basal hypothalamus (MBH) was incubated with Locke's medium at 37 degrees C for 30 min. Concentrations of TSH in medium and plasma samples as well as the cyclic 3':5' adenosine monophosphate (cAMP) content in APs and the levels of TRH in MBH medium were measured by radioimmunoassay. The levels of plasma TSH were higher in pregnant rats of day 21 than in diestrous rats. The spontaneous release of TSH in vitro was unaltered by pregnancy. TRH increased the release of TSH by AP, which was higher in pregnant than in diestrous rats. Maternal serum concentration of total T3 was decreased during the pregnancy. The basal release of hypothalamic TRH in vitro was greater in late pregnant rats than in diestrous rats. After TRH stimulation, the increase of the content of pituitary cAMP was greater in late pregnant rats than in diestrus animals. These results suggest that the greater secretion of TSH in pregnant rats is in part due to an increase of spontaneous release of TRH by MBH and a decrease of plasma thyroid hormones. Moreover, the higher level of plasma TSH in rats during late pregnancy is associated with the greater response of pituitary cAMP and TSH to TRH.

Inhibitory effect of digoxin on testosterone secretion through mechanisms involving decreases of cyclic AMP production and cytochrome P450scc activity in rat testicular interstitial cells

1. In vivo and in vitro experiments were performed to examine inhibitory effects of digoxin on testosterone secretion and to determine possible underlying mechanisms. 2. A single intravenous injection of digoxin (1 microg kg(-1)) decreased the basal and human chorionic gonadotropin (hCG)-stimulated plasma testosterone concentrations in adult male rats. 3. Digoxin (10(-7) - 10(-4) M) decreased the basal and hCG-stimulated release of testosterone from rat testicular interstitial cells in vitro. 4. Digoxin (10(-7) - 10(-4) M) also diminished the basal and hCG-stimulated production of cyclic 3':5'-adenosine monophosphate (AMP) and attenuated the stimulatory effects of forskolin and 8-Br-cyclic AMP on testosterone production by rat testicular interstitial cells. 5. Digoxin (10(-4) M) inhibited cytochrome P450 side chain cleavage enzyme (cytochrome P450sec) activity (conversion of 25-hydroxy cholesterol to pregnenolone) in the testicular interstitial cells but did not influence the activity of other steroidogenic enzymes. 6. These results suggest that digoxin inhibits the production of testosterone in rat testicular interstitial cells, at least in part, via attenuation of the activities of adenylyl cyclase and cytochrome P450sec.

The human N-methyl-D-aspartate receptor 2C subunit: genomic analysis, distribution in human brain, and functional expression

cDNAs encoding four isoforms of the human NMDA receptor (NMDAR) NMDAR2C (hNR2C-1, -2, -3, and -4) have been isolated and characterized. The overall identity of the deduced amino acid sequences of human and rat NR2C-1 is 89.0%. The sequences of the rat and human carboxyl termini (Gly925-Val1,236) are encoded by different exons and are only 71.5% homologous. In situ hybridization in human brain revealed the expression of the NR2C mRNA in the pontine reticular formation and lack of expression in substantia nigra pars compacta in contrast to the distribution pattern observed previously in rodent brain. The pharmacological properties of hNR1A/2C were determined by measuring agonist-induced inward currents in Xenopus oocytes and compared with those of other human NMDAR subtypes. Glycine, glutamate, and NMDA each discriminated between hNR1A/2C-1 and at least one of hNR1A/2A, hNR1A/2B, or hNR1A/2D subtypes. Among the antagonists tested, CGS 19755 did not significantly discriminate between any of the four subtypes, whereas 5,7-dichlorokynurenic acid distinguished between hNR1A/2C and hNR1A/2D. Immunoblot analysis of membranes isolated from HEK293 cells transiently transfected with cDNAs encoding hNR1A and each of the four NR2C isoforms indicated the formation of heteromeric complexes between hNR1A and all four hNR2C isoforms. HEK293 cells expressing hNR1A/ 2C-3 or hNR1A/2C-4 did not display agonist responses. In contrast, we observed an agonist-induced elevation of intracellular free calcium and whole-cell currents in cells expressing hNR1A/2C-1 or hNR1A/2C-2. There were no detectable differences in the macroscopic biophysical properties of hNR1A/2C-1 or hNR1A/2C-2.

Age-related differences in the secretion of calcitonin in female rats

The mechanism that causes hypercalcitonemia in female rats and is associated with aging was investigated. Young (3 mo), adult (8 mo), middle-aged (12 mo), and old (21 mo) rats were infused with CaCl2 and were bled from a jugular catheter after a CaCl2 challenge. To mimic some of the hormonal changes caused by aging, the anterior pituitary (AP)-grafted ovariectomized rats with hyperprolactinemic syndrome were used to mimic the physiological status of aging. The rat thyroid gland was incubated with or without ovine prolactin (oPRL; 40 or 80 ng/ml) at 37 degreesC for 30 min. Old rats possessed the lowest levels of plasma estradiol and progesterone yet had the highest levels of plasma prolactin and calcitonin (CT) compared with young, adult, and middle-aged rats. The basal release of thyroid CT in vitro in thyroid glands gradually increased with age. Compared with cortex (CX)-grafted rats, the AP-grafted rats possessed higher levels of plasma PRL, basal and CaCl2-induced levels of plasma CT, and the release of thyroid CT in thyroid glands. After stimulation with oPRL, the in vitro release of thyroid CT increased in both CX- and AP-grafted rats. These results suggest that the hypersecretion of CT in old rats is due at least in part to hyperprolactinemia.

Effects of methanol extract of Chansu on hypothalamic-pituitary-testis function in rats

Chansu, a galenical preparation of the dried white venom of Chinese Bufo bufo gargarizans, is one of the major components of Kyushin, a traditional Chinese medicine. Kyushin is reported to have a cardiotonic effect that has been suggested to be due to the action of bufadienolides such as bufalin and cinobufagin. Recently, we found that administration of bufalin in male rats diminished the luteinizing hormone (LH) response to gonadotropin-releasing hormone (GnRH) and the secretion of testosterone both in vivo and in vitro. These observations suggest that Chansu may possess hypogonadal effects in male rats. In the present study, the effects of the methanol extract of Chansu on hypothalamic-pituitary-testicular function in male rats were examined. Crude Chansu was extracted by methanol and purified by a Sep-Pak C18 column. No activity of bufalin, cinobufagin, estradiol, or digoxin in purified methanol extract was detected; all Chansu used in this study was the purified methanol extract. A single intravenous injection of Chansu resulted in a decrease of the basal (20% to 55%) and human chorionic gonadotropin (hCG)-induced (35% to 40%) levels of plasma testosterone and the GnRH-induced level of plasma LH (25% to 30%). Administration of Chansu in vitro decreased basal and hCG-stimulated testosterone production by 60% to 70% and 40% to 60%, respectively, as well as spontaneous and forskolin- or 3-isobutyl-1-methylxanthine (IBMX)-induced accumulation of adenosine 3',5'-cyclic monophosphate (cAMP) by 30% to 45% in rat testicular interstitial cells. Although LH release by rat anterior pituitary glands was diminished, GnRH release by the rat mediobasal hypothalamus was enhanced by administration of Chansu in vitro. These results suggest that the bufalin-free extracts of Chansu inhibit testosterone secretion in rats, in part, due to (1) a decreased production of testicular cAMP, (2) a decreased response of testosterone to gonadotropin, and (3) a reduction of the LH response to GnRH.

Influence of referral source on return compliance of adolescents

PURPOSE

To determine the effect of the source of referral on appointment compliance of adolescents to referring doctors or to consultants at tertiary medical centers.

METHODS

This analysis included 421 adolescent patients aged 10-18 years who were referred to the tertiary teaching hospital in Taiwan by 75 primary care doctors, including 56 pediatricians and 19 general practitioners in 1987-1996. Medical records were abstracted to determine clinical severity and demography. Data of compliance with return appointments were collected by an independently trained interviewer.

RESULTS

A total of 18.07% of referrals were initiated by patients or families and 81.93% were initiated by primary care doctors. More severe illness was found in patient-initiated referrals than in doctor-initiated referrals. After controlling for demographic, family features, medical payment, and doctor specialty, this study showed that if the referral were initiated by patients or families, adolescent patients were less likely to return to either the primary care doctors or tertiary teaching hospitals.

CONCLUSIONS

Although in a competitive environment, follow-up care is more likely to occur for both primary care doctors and consultants at tertiary teaching hospitals when the referral was initiated by primary care doctors.

Randomized, double-blind, placebo-controlled study of transdermal nicotine patch for smoking cessation

Smoking cessation is an arduous process because nicotine withdrawal syndrome, which occurs following sudden interruption of nicotine use in long-term smokers, frequently prevents them from giving up the habit. Nicotine supplement systems may relieve smokers' nicotine withdrawal symptoms and, thus, help in the process of abstinence from smoking. The purpose of the present study was to investigate the effectiveness and safety of a 30-mg transdermal nicotine patch in a smoking cessation program for Chinese smokers. In this randomized, double-blind, placebo-controlled study, 30 heavy smokers, who had smoked more than 20 cigarettes per day for more than a year, were treated with 30-mg transdermal nicotine patches, and 32 heavy smokers were given placebo patches during a 6-week smoking cessation program. The clinical characteristics of the two groups were similar. After 6 weeks, the use of the transdermal nicotine patch was associated with markedly reduced nicotine dependence and severity of withdrawal symptoms. Nineteen (63%, 95% confidence interval, CI, 46%-80%) of the smokers treated with the transdermal nicotine patch had successfully quit smoking at the end of the program (6 weeks) and nine (30%, 95% CI 14%-46%) remained abstinent 1 year later. In contrast, only 11 (34%, 95% CI 18%-50%) of the smokers in the placebo group had successfully stopped smoking after 6 weeks, and three remained abstinent 1 year later (9%, 95% CI 0%-19%). However, there was no statistically significant difference between the two groups of smokers after 1 year of follow-up (p = 0.08). Side-effects were minimal and did not affect the efficacy of the skin patch. The results indicate that the transdermal nicotine patch is an effective aid in smoking cessation programs.

Inhibition of gastric emptying and intestinal transit by amphetamine through a mechanism involving an increased secretion of CCK in male rats

1. The effect of amphetamine on gastrointestinal (GI) transit and the plasma levels of cholecystokinin (CCK) were studied in male rats. 2. Gastric emptying was inhibited both acutely and chronically by the administration of amphetamine. GI transit was decreased by the acute administration of amphetamine but not affected by the chronic administration of amphetamine. 3. Plasma CCK levels were increased dose-dependently by amphetamine. 4. Proglumide, a CCK receptor antagonist, prevented amphetamine-induced inhibition of gastric emptying and the decrease in GI transit in male rats. 5. The selective CCK(A) receptor antagonist, lorglumide, dose-dependently attenuated the amphetamine-induced inhibition of gastric emptying in male rats. In contrast, the selective CCK(B) receptor antagonist, PD 135,158, did not reverse the effect of amphetamine on gastric emptying. 6. Both lorglumide and PD 135,158 reversed the inhibitory effect of amphetamine on GI transit in male rats. 7. These results suggest that amphetamine-induced inhibition of gastric emptying and intestinal transit is due in part to a mechanism associated with the hypersecretion of endogenous CCK.