Functional characterization of human N-methyl-D-aspartate subtype 1A/2D receptors

The human NMDAR2D subunit was cloned, and the pharmacological properties of receptors resulting from injection of transcripts encoding human NMDAR1A and NMDAR2D subunits in Xenopus oocytes were characterized by profiling NMDA receptor agonists and antagonists. We found that glutamate, NMDA, glycine, and D-serine were significantly more potent on hNMDAR1A/2D than on hNMDAR1A/2A or hNMDAR1A/2B. Also, the potencies of NMDA and glycine were higher for hNMDAR1A/2D than for hNMDAR1A/2C. Ifenprodil was more potent at hNMDAR1A/2B than at hNMDAR1A/2D, whereas 5,7-dichlorokynurenate was more potent at hNMDAR1A/2A than at hNMDAR1A/2D. As measured in transiently transfected human embryonic kidney 293 cells, the maximal inward current in the presence of external Mg2 occurred at -40 mV, and full block was not observed at negative potentials. Kinetic measurements revealed that the higher affinity of hNMDAR1A/2D for both glutamate and glycine relative to hNMDAR1A/2A and hNMDA1A/2B can be explained by slower dissociation of each agonist from hNMDAR1A/2D. The hNMDAR1A/2D combination represents a pharmacologically and functionally distinct receptor subtype and may constitute a potentially important target for therapeutic agents active in the human CNS.

Effects of ovarian steroid hormones and thyroxine on calcitonin secretion in pregnant rats

In the present study, the roles of ovarian steroid hormones and thyroxine (T4) in regulating the secretion of calcitonin (CT) in pregnant rats were examined. The levels of plasma progesterone, pre- and post-CaCl2 plasma CT, and recovery time of plasma CT and calcium after calcium challenge were greatest in midterm pregnant rats. The levels of basal plasma progesterone, CT, calcium, and recovery time of plasma CT after calcium challenge were less in late pregnant rats, but basal plasma estradiol was highest in late pregnancy. The concentrations of plasma T4 were gradually decreased in rats during pregnancy. Regardless of the presence of estradiol, administration of progesterone in ovariectomized (Ovx) rats resulted in an increase of plasma T4 as well as the basal and calcium-induced secretion of CT. Administration of estradiol alone did not alter the CaCl2-induced levels but decreased the post-CaCl2 levels of plasma calcium in Ovx rats. The basal levels of plasma CT were decreased in Ovx rats treated with T4. These results suggest that the hypercalcitoninemia in midterm pregnant rats is due to an increased secretion of progesterone. Hypocalcitoninemia in late pregnant rats, however, is due in part to lower plasma calcium.

Acute effects of thyroid hormones on the production of adrenal cAMP and corticosterone in male rats

The acute effects of thyroid hormones on glucocorticoid secretion were studied. Venous blood samples were collected from male rats after they received intravenous 3,5,3'-triiodothyronine (T3) or thyroxine (T4). Zona fasciculata-reticularis (ZFR) cells were treated with adrenocorticotropic hormone (ACTH), T3, T4, ACTH plus T3, or ACTH plus T4 at 37 degrees C for 2 h. Corticosterone concentrations in plasma and cell media, and also adenosine 3',5'-cyclic monophosphate (cAMP) production in ZFR cells in the presence of 3-isobutyl-1-methylxanthine, were determined. The effects of thyroid hormones on the activities of steroidogenic enzymes of ZFR cells were measured by the amounts of intermediate steroidal products separated by thin-layer chromatography. Administration of T3 and T4 suppressed the basal and the ACTH-stimulated levels of plasma corticosterone. In ZFR cells, both thyroid hormones inhibited ACTH-stimulated corticosterone secretion, but the basal corticosterone was inhibited only with T3 > 10(-10) M or T4 > 10(-8) M. Likewise, T3 or T4 at 10(-7) M inhibited the basal- and ACTH-stimulated levels of intracellular cAMP. Physiological doses of T3 and T4 decreased the activities of 3 beta-hydroxysteroid dehydrogenase, 21-hydroxylase, and 11 beta-hydroxylase. These results suggest that thyroid hormones counteract ACTH in adrenal steroidogenesis through their inhibition of cAMP production in ZFR cells.

Interaction between triiodothyronine and ovarian steroid hormones on the regulation of the release of thyrotropin and thyrotropin-releasing hormone in vitro

In vivo and in vitro experiments were designed to examine [1] the effect of triiodothyronine (T3) and/or ovarian steroids on the spontaneous and thyrotropin-releasing hormone (TRH)-stimulated release of thyrotropin (TSH) by the anterior pituitary gland (AP) in vitro; and [2] the in vivo effects of T3 and ovarian steroids on TRH-release in vitro. In the experiment 1, ovariectomized-thyroidectomized (Ovx-Tx) rats were injected with triiodothyronine (T3, 2 micrograms/kg), estradiol benzoate (EB, 25 micrograms/kg), progesterone (P, 10 mg/kg), T3 plus EB, T3 plus P, EB plus P, or T3 plus EB and P for 6 days before decapitation. The AP was incubated with Locke's medium, challenged with TRH (30 nM), recovered and then with T3 (10 nM) only or with T3+TRH, 30 min for each interval. Mediobasal hypothalami (MBHs) were challenged with high potassium (60 mM) for 30 min. In the experiment 2, the APs of Ovx-Tx rats were enzymatically dispersed and the AP cells were pretreated with or without EB (0-6 nM) for 72 h, and further with T3 (10 nM) for 24 h, followed by an incubation for 30 min with TRH (0-100 nM). The spontaneous and TRH-induced release of TSH in vitro from rat APs, and pituitary TSH content were increased by T3, or T3 plus P as compared with the animals injected with vehicle, or P alone. EB inhibits the effect of T3 on TSH release in vitro. Application of T3 in vitro prevented the release of TSH in response to TRH. EB dose-dependently relieved the inhibitory effect of T3 on TRH-induced TSH release in vitro. TRH release from MBH was increased by EB and inhibited by T3 or P. EB prevented the inhibitory effect of T3 on TRH release. P plus T3 potentiated the stimulatory effects of EB on TRH release. These results suggest that [1] the reduction of the concentration of plasma TSH by T3 is at least in part due to the inhibitory effects of T3 on TRH release from mediobasal hypothalamus, and TSH release in response to TRH, [2] the increased content and release of TSH from rat AP tissue by T3 via an in vivo effect may be involved in a short feedback loop of TSH on TRH release, and [3] ovarian steroid hormones play an inhibitory role in regulating T3 effects on the release of TSH and TRH.

Bronchodilator therapy for chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a heterogeneous group of diseases characterized by cough, sputum production, dyspnoea, airflow limitation and bronchial hyperreactivity. The airflow limitation declines progressively and is irreversible or partially reversible. Bronchodilator therapy is prescribed to relieve the symptoms, reverse airway obstruction and hopefully slow the rate of disease progression and decelerate the decline in pulmonary function. During acute exacerbation, inhalation of beta2-agonists remain the therapy of choice. The usefulness of anticholinergic inhalation in acute attacks is investigated in order to determine if a higher dose and more frequent administration have same benefit as beta2-agonists inhalation. Theophylline is usually given orally as a sustained release formulation for chronic maintenance therapy. Some patients may benefit from theophylline infusion during an acute phase when appropriately used; however, sympathomimetic agents fail to produce adequate bronchodilation. During interim periods of stability, inhalation of ipratropium bromide has increased in popularity as a regular long-term bronchodilator therapy. Although ipratropium and beta2-agonists are equally efficacious when the dosage is adequate enough, a combination of both provides a rapid onset of action of the adrenergic agents and a prolonged action of the anticholinergic. Furthermore, this combination can be given in a reduced dose, thereby avoiding side-effects. Inhalation techniques can influence the efficacy of bronchodilator therapy. For severe dyspnoeic patients or patients with poor technique of co-ordination with metered-dose inhaler (MDI), attachment of a spacer to the MDI or using a nebulizer will overcome these difficulties. Bronchodilator therapy can not prevent the development of COPD or slow down the decline of pulmonary function, other interventions should be included in a comprehensive management programme.

Inhibition of bufalin on pituitary and testicular function in rats

The effects of bufalin on the secretion of testosterone and luteinizing hormone (LH) and the accumulation of testicular adenosine 3':5'-cyclic monophosphate (cAMP) were studied. Male rats were injected with bufalin, human chorionic gonadotropin (hCG), gonadotropin releasing hormone (GnRH), hCG plus bufalin or GnRH plus bufalin via a jugular catheter. Blood samples were collected at several intervals subsequent to the challenge. In the in vitro study, rat testis blocks were incubated with bufalin, hCG or both for 1 h. The anterior pituitary gland was incubated with bufalin, GnRH or both for 30 min. The media were analyzed for testosterone or LH. For studying cAMP accumulation, testicular blocks were incubated for 1 h with the medium containing isobutyl-1-methylxanthine. After incubation, tissues were extracted by ethanol before measuring cAMP concentration. A single intravenous injection of bufalin decreased the basal and hCG-stimulated levels of plasma testosterone. Administration of bufalin in vitro resulted in an inhibition of both basal and hCG-stimulated release of testosterone. Bufalin diminished cAMP accumulation in rat testes. However, the basal levels of plasma and medium LH were not altered by bufalin administration. Likewise, the LH response to GnRH was diminished by bufalin administration, both in vivo and in vitro. These results suggest that the inhibition of testosterone production by bufalin is partly caused by a decrease of testicular cAMP accumulation and LH response to GnRH in rats.

The role of cyclic AMP production, calcium channel activation and enzyme activities in the inhibition of testosterone secretion by amphetamine

1. The aim of this study was to investigate the mechanism by which amphetamine exerts its inhibitory effect on testicular interstitial cells of male rats. 2. Administration of amphetamine (10(-12)-10(-6) M) in vitro resulted in a dose-dependent inhibition of both basal and human chorionic gonadotropin (hCG, 0.05 iu ml(-1))-stimulated release of testosterone. 3. Amphetamine (10(-9) M) enhanced the basal and hCG-increased levels of adenosine 3':5'-cyclic monophosphate (cyclic AMP) accumulation in vitro (P<0.05) in rat testicular interstitial cells. 4. Administration of SQ22536, an adenylyl cyclase inhibitor, decreased the basal release (P<0.05) of testosterone in vitro and abolished the inhibitory effect of amphetamine. 5. Nifedipine (10(-6) M) alone decreased the secretion of testosterone (P<0.01) but it failed to modify the inhibitory action of amphetamine (10(-10)-10(-6) M). 6. Amphetamine (10(-10)-10(-6) M) significantly (P<0.05 or P<0.01) decreased the activities of 3beta-hydroxysteroid dehydrogenase (3beta-HSD), P450c17, and 17-ketosteroid reductase (17-KSR) as indicated by thin-layer chromatography. (t.l.c.). 7. These results suggest that increased cyclic AMP production, decreased Ca2+ channel activity and decreased activities of 3beta-HSD, P450c17, and 17-KSR are involved in the inhibition of testosterone production induced by the administration of amphetamine.

Lactate and the effects of exercise on testosterone secretion: evidence for the involvement of a cAMP-mediated mechanism

The effects of swimming and lactate on the release of testosterone were examined in male rats. During in vivo experiments, male rats were catheterized via the right jugular vein and blood was collected at 0, 10, 15, 30, and 60 min following the exercise, or they were catheterized via the right jugular vein and the left femoral vein and blood was collected at 0, 2, 5, 10, 15, 30, 60, and 120 min after a 10-min infusion at lactate (13 mg.kg-1.min-1). Trunk blood and blood from the testicular vein were also collected after 10 min of swimming or water immersion. In an in vitro experiment, testicular fragments were challenged with lactate (0.01-10 mM) and/or human chorionic gonadotropin (hCG; 0.5 IU.mL-1), and the mediobasal hypothalamus (MBH) was challenged with lactate (8 mM). The post-exercise levels of plasma lactate and testosterone at 10, 15, and 30 min were higher than resting levels. Plasma luteinizing hormone (LH) was increased following 30 min of swimming. Administration of lactate or hCG increased in a dose dependent manner testicular cyclic adenosine 3':5' monophosphate (cAMP) and testosterone release. Plasma testosterone increased after swimming and lactate infusion. Incubation of MBH with lactate increased the gonadotropin-releasing hormone (GnRH) level in the medium. These results suggest that the increased plasma testosterone levels in male rats during exercise is at least partially a result of a direct and LH-independent stimulatory effect of lactate on the secretion of testosterone by increasing testicular cAMP production. Swim-elevated plasma LH may be a result of a rise of GnRH caused by lactate.

Diagnostic imaging in the evaluation of constipation in adults

Acute and chronic constipation are common conditions. In most instances, a thorough history and digital rectal examination provide sufficient information to begin treatment. Occasionally, imaging studies can be useful to confirm the presence of a suspected abnormality. The acute onset of constipation suggests colonic obstruction. Plain abdominal radiographs may be sufficient to determine the level and cause of the obstruction, such as sigmoid or cecal volvulus. Barium enema radiographic examination or colonoscopy may also be useful to detect the cause of obstruction. In patients with chronic constipation, plain abdominal radiographs can be used to show the extent of fecal impaction. Colonic transit time can be assessed on serial abdominal radiographs after the patient has ingested radiopaque markers. Evacuation proctography can be used to diagnose a variety of functional disorders of the rectum and anus, such as rectocele, intussusception and abnormal perineum floor descent.

Parathyroid hormone and parathyroid hormone related protein assays in the investigation of hypercalcemic patients in hospital in a Chinese population

There are many pathological causes and potential mechanisms for hypercalcemia. We measured intact parathyroid hormone (PTH) and parathyroid hormone related protein (PTHrP) in the hypercalcemic in-patients and attempted to evaluate the roles of PTH and PTHrP in hypercalcemia due to malignancy. We performed a prospective study of 178 patients with corrected serum calcium concentrations greater than 2.74 mmol/l in a hospital over a 3-year period. We measured calcium and albumin using a Hitachi 747 autoanalyzer, and we measured PTH and PTHrP by two-site immunoradiometric assays (IRMA). Hypercalcemia was attributed to malignancy alone in 93 patients (52.3%), primary hyperparathyroidism (HPT) alone in 28 patients (15.7%), uremia with hemodialysis in 23 patients (12.9%), unknown in 16 patients (9%), primary HPT coexisting with malignancy in 7 patients (3.9%) and other rare causes (6.2%). Plasma PTHrP levels were elevated in 71/93 (76.3%) patients with hypercalcemia due to malignancy, but the elevated PTHrP percentage differed for each kind of tumor. PTHrP levels were elevated in 100% of patients with squamous carcinomas (CA) in the lung, esophagus, skin, cholangiocarcinoma of liver, and breast CA. The positive bony metastatic rate was 44.1% (41/93). There was no correlation between high PTHrP and bony metastasis. There was a good correlation between the corrected serum calcium and PTHrP levels (r = 0.476, p < 0.001), but no correlation between survival time and serum calcium level or PTHrP level. There was no significant difference in life expectancy after cancer diagnosis between the high PTHrP group and normal PTHrP group, and there was no significant difference in life expectancy after the first occurrence of hypercalcemia between the two groups. Measurement of both PTH and PTHrP levels led to a change in the initial diagnosis in 7 patients. In routine practice, measurement of serum PTH alone is not enough. This study suggests that the appropriate combination of PTH and PTHrP assays results in a more accurate diagnosis of the hypercalcemic causes. In addition, especially high PTHrP levels should be screened for malignancy. However, the prognosis in cancer patients after hypercalcemia with high PTHrP group, as compared to those with the normal PTHrP group is not significantly different.

Gastric emptying and gastrointestinal transit during lactation in rats

Female sex hormones can influence gastrointestinal function. To understand whether postpartum changes in female sex hormones may affect such function, gastric emptying and gastrointestinal transit were measured in rats on days 1-2, 10, 15, and 21 of lactation, on day 7 postweaning, and at the nonpregnant diestrous stage. Gastric emptying and gastrointestinal transit were assessed in conscious rats 15 min after intragastric instillation of a test meal containing charcoal and (51)Cr. The results showed that gastric emptying was increased throughout the first 2 wk of lactation, with a gradual decrease as lactation proceeded toward weaning, and returned to the level of the virgin rats by 1 wk postweaning. Gastrointestinal transit was greater in the early stage of lactation and was related to gastric emptying (P < 0.001). Increases in gastric emptying and intestinal length were correlated with lactation (P < 0.001) and plasma prolactin levels (P < 0.05) but not with plasma progesterone or estradiol levels. We concluded that the sex steroid hormones associated with lactation do not mediate a change in gastric emptying and gastrointestinal transit during lactation.

Pre-emptive analgesia with ketamine, morphine and epidural lidocaine prior to total knee replacement

PURPOSE

Pre-emptive analgesia can improve postoperative pain management. The purpose of this study was to examine the effectiveness of ketamine as a pre-emptive analgesic as previous studies have shown the involvement of N-methyl-D-Aspartate (NMDA) receptor in neuroplasticity.

METHODS

Forty-five ASA 1-2 patients, undergoing unilateral total knee replacement were studied. In the study groups, epidural lidocaine was used as the primary anaesthestic. Patients received ketamine + morphine epidurally 30 min either before (group EB) or after skin incision (group EA). Group G patients received general anaesthesia and ketamine + morphine were given 30 min after skin incision via an epidural catheter used for postoperative pain control. Epidural morphine and ketamine in lidocaine was given to all patients at the end of surgery and every 12 hr for three days for analgesia supplemented with PCA morphine. The time until first PCA trigger, morphine consumption, pain scores, satisfaction scores, and morphine related side effects were recorded at 6, 12, 24, 48 and 72 hr after surgery.

RESULTS

Epidural ketamine plus morphine with lidocaine before surgical incision produced better pain relief and patient satisfaction than when given after incision. A longer time to PCA and decreased morphine consumption were observed in group EB than in group G. In group EA, epidural anaesthesia also produced some pre-emptive analgesic effect compared with general anaesthesia shown by decreased morphine consumption.

CONCLUSIONS

Administration of ketamine plus morphine with epidural lidocaine anesthesia before surgery provided improved postoperative analgesia compared with general anaesthesia alone or when analgesics were given after skin incision.

Inhibition of corticosterone secretion by thyroxine in male rats

The effects of thyroxine (T4) on the secretion of corticosterone both in vivo and in vitro in male rats were studied. Rats were thyroidectomized (Tx) or sham Tx. The Tx rats were subcutaneously with T4 (20 micrograms/kg) or saline once daily for two weeks. In an in vitro experiment, adrenal glands were incubated with ACTH, T4, or ACTH plus T4 in the presence or absence of 0.5 mM 3-isobutyl-1-methylxanthine (IBMX) at 37 degrees C for 60 min. Medium and ether-extracted plasma samples were analyzed for corticosterone by radioimmunoassay (RIA). The accumulation of cyclic adenosine monophosphate (cAMP) in adrenal tissues after incubation with IBMX was measured by RIA. The levels of plasma corticosterone in Tx rats were significantly increased as compared with euthyroid rats. T4 replacement in Tx rats restored plasma corticosterone to euthyroid level. Administration of T4 in vitro resulted in an inhibition of both basal and ACTH-stimulated release of corticosterone. Both basal and ACTH-stimulated generations of cAMP in adrenal tissues were decreased by T4. These results suggest that T4 inhibits the spontaneous and ACTH-stimulated secretion of corticosterone by acting directly at adrenal glands via a decrease in cAMP production.

Activation of the hepatitis B virus S promoter by transcription factor NF-Y via a CCAAT element

The middle and small surface proteins of hepatitis B virus are translated from 5'-heterogeneous transcripts specified by the S promoter. We have generated a series of linker-substitution mutants that encompass the 130 base pairs comprising this promoter and measured the amount of transcripts and protein products synthesized from each mutant. The results confirm our previous finding that a CCAAT element is an important up-stream activating element for this promoter, as mutation of this element leads to a >20-fold decrease in promoter activity. In vitro binding assays showed that the cellular transcription factor NF-Y (CCAAT-binding factor) binds to this element, and expression of a dominant-negative NF-Y subunit in transfected cells specifically reduced surface protein expression from the S promoter via the CCAAT element. In addition, two Sp1 sites also contribute to S promoter activity by a total of approximately 6-fold. Therefore, the S promoter is activated by both NF-Y and Sp1, but more strongly by the former factor.

Effect of aging on erythropoietin secretion in male rats

The secretion of erythropoietin (EPO) and testosterone in response to hypoxia in old (22-25 months), middle (mid)-aged (15-17 months), adult (6-7 months), and young (3 months) male rats was studied. Rats of different ages were bled by cardiac puncture before and subsequent to 8 h exposure to 12% O2. The metabolic clearance rate of EPO was determined by a single-injection method. The effects of orchidectomy and replacement of testosterone propionate on plasma EPO concentrations were also investigated. Analysis of the direct effects of testosterone on EPO release from kidney tissue was carried out in an in vitro study. Both basal and hypoxia-induced EPO levels were lower in old rats than in mid-aged, adult, and young rats (p < .01). Plasma testosterone levels decreased in response to hypoxia in all rats (p < .01 for young, adult, and mid-aged rats, and p < .05 for old rats). The old rats also had lower plasma testosterone levels following hypoxia when compared with other rats (p < .05). The metabolic clearance rate of EPO was not affected by age. Orchidectomy decreased rat plasma EPO concentration (p < .05). This decrease could be restored to intact levels after testosterone propionate replacement. Both 10(-10) M (p < .05) and 10(-9) M (p < .01) testosterone stimulate EPO release from kidney tissue in vitro. Our findings indicate that the basal levels of plasma EPO and testosterone are decreased, and the hypoxia-induced EPO is also diminished with aging in male rats. These data suggest that the mechanism of tolerance to hypoxia and the endocrine function of the kidneys in male rats during the aging process are testosterone-dependent.

Lactate stimulates progesterone secretion via an increase in cAMP production in exercised female rats

The effect of exercise on the production of ovarian progesterone was examined in female rats. During in vivo experiments, diestrous rats were catheterized via the right jugular vein (RJV), and blood samples were collected before and after 10, 15, 30, and 60 min of swimming. In addition, blood samples were collected from the RJV before and 2, 5, 10, 15, 30, 60, and 120 min after 10 min of infusion of lactate (13 mg.kg-1.min-1) through the left femoral vein. To explore if lactate modulates progesterone secretion by acting directly on rat ovary or on anterior pituitary gland (AP), an in vitro experiment that mimicked the in vivo condition was performed. The ovarian tissue was challenged with lactate (0.01-10 mM) or porcine follicle-stimulating hormone (1 microgram/ml) and 3-isobutyl-1-methylxanthine (1 mM) for 60 min, and the AP was challenged with lactate ranging from 0.1 to 10 mM or 10 nM gonadotropin-releasing hormone for 30 min. The postexercise levels of plasma glucose, lactate, and progesterone at 10, 15, and 30 min were significantly higher than the corresponding basal levels. Plasma luteinizing hormone (LH) did not change after exercise. An elevation of plasma lactate and progesterone was found at 15 and 30 min subsequent to 10 min of infusion of lactate. Lactate ranging from 0.01 to 10 mM significantly increased ovarian adenosine 3',5'-cyclic monophosphate (cAMP) and progesterone production in a dose-dependent manner. LH concentration in plasma was not changed subsequent to lactate infusion. LH level in media samples was not altered after incubation of AP with lactate. These results suggest that the increase of plasma progesterone level in rats during exercise is independent of LH secretion and at least in part is due directly to a stimulatory effect of lactate on the production of ovarian cAMP.

Use of the silicone tracheal T-tube for tracheostenosis or tracheomalacia

BACKGROUND

Tracheobtenosib and tracheomalacia are trivial diseases. The conventional choice of managements with tracheostomy, either temporary or long-term usage, can only partially resolve the problems of airway obstruction. Silicone tracheal T-tube presents a substitute for it.

METHODS

We present 5 patients with tracheostenosis or tracheomalacia managed with nine procedures of long silicone Montgomery T-tube prothesis between 1984 and 1994 in VGH-Taipei. The primary diagnosis included tracheal injury (2), postintubation tracheal stenosis (2), and stenosis due to endotracheal tuberculosis (1). Three patients received a long segmental T-tube for permanent endotracheal stenting and the other two patients used T-tube insertion for temporary stenting of the trachea for 7 and 11 months, respectively, with satisfactory results.

RESULTS

All patients got immediate benefit from the prothesis in respiration with simple postoperative care. Two patients with temporary T-tube placement had it successfully removed in 7 and 11 months, respectively. Placement of the T-tube for subglottic stenosis also protected the function of phonation. The tracheal T-tube restored airway patency reliably with good long-term results and could be the preferred management of chronic upper airway obstructive disease not amenable to surgical repair. The most common complication was airway obstruction caused by either granulations or sticky mucoid substance. Three patients and six tubes (60%) developed granulation obstruction and the average duration of granuloma formation was 7.7 months. Laser phototherapy or surgical intervention, such as tracheoplasty, with change of the T-tube was carried out for granuloma obstruction.

CONCLUSIONS

T-tube is a good endoprothesis for tracheostenosis and tracheomalacia with minimal complication for cases of long tracheostenosis or complex tracheal injury.

Direct measurement of neutrophil F-actin content in microvolume whole blood samples

BACKGROUND

The traditional methods of measuring F-actin content in neutrophils required a large blood sample and a series of isolation procedures. To reduce the disturbing effect on neutrophils, a new method was designed to measure the neutrophil F-actin content directly in microvolume whole blood samples.

METHOD

The neutrophil F-actin content was measured in 100 microliters of whole blood directly after formyl-Met-Leu-Phe (FMLP) stimulation and lysis of red blood cells (with FACS lysing solution, Becton, Dickinson Immunocytometry Systems, San Jose, Calif.).

RESULTS

This method resulted in a typical dose-dependent increase in the neutrophil F-actin content in response to FMLP similar to that using isolated neutrophils. However, the relative F-actin content of whole blood samples was significantly higher than those of isolated neutrophils at 60 and 300 s after stimulation (2.44 +/- 0.21 vs. 2.00 +/- 0.22 at 60 s, p < 0.05, n = 16; 1.77 +/- 0.19 vs. 1.48 +/- 0.19 at 300 s, p < 0.05, n = 16). The histograms of whole blood samples at 30 and 60 s after stimulation showed a subpopulation (17.5 +/- 2.7%) of lower F-actin content, which cannot be definitely identified in the isolated neutrophil samples. Furthermore, the neutrophil actin response to FMLP in a pair of premature twins was analyzed using this method. The response of the healthy twin is similar to that of the adult volunteers while that of the septic one is characterized by an increasing number of nonresponsive cells as the clinical condition deteriorated.

CONCLUSION

This new method is effective in evaluating the neutrophil F-actin content even in premature infants. It is characterized by avoiding most of the isolation procedures which might have an activating effect on neutrophils. Besides, the study of the twins also indicated the usefulness of this method in monitoring the clinical course of neonatal sepsis.

Cloning and functional characterization of human heteromeric N-methyl-D-aspartate receptors

Human cDNAs encoding N-methyl-D-aspartate receptor type (NMDAR)1A, NMDAR2A and NMDAR2B subunits were cloned and receptors encoded by these cDNAs were functionally expressed by injection of the respective mRNAs in Xenopus oocytes. The pharmacological properties of recombinant human N-methyl-D-aspartate (NMDA) receptors were characterized by profiling two agonists and four antagonists at both the NMDA and glycine sites in voltage-clamped oocytes. NMDA, glycine and D-serine were significantly more potent at human NMDAR (hNMDAR)1A/2B receptors than at nNMDAR1A/2A, whereas there was no detectable subtype-dependent difference in the potency of glutamate. Of the NMDA-site antagonists tested, CGP 43487 and 3-(2-carboxypiperazin-4-yl) propyl-1-phosphonate exhibited 5.8- and 3.9-fold greater potency, respectively, at hNMDAR1A/2A receptors than at hNMDAR1A/2B. Of the four glycine-site competitive antagonists tested, L-689,560 displayed 5-fold greater potency at hNMDAR1A/2A, whereas 5,7-dichlorokynurenic acid, HA-966 and CGP 58411 did not discriminate between hNMDAR1A/2A and hNMDAR1A/2B. Receptors resulting from injection of hNMDAR1A, hNMDAR2A and hNMDAR2B transcripts in a 1:1:1 ratio were indistinguishable from hNMDAR1A/2B receptors in terms of their sensitivity to NMDA, glycine, D-serine, CGS 19755 and CGP 40116. Ifenprodil was approximately 350-fold more potent at hNMDAR1A/2B than at hNMDAR1A/2A receptors. Ifenprodil sensitivities of receptors formed in oocytes injected with a constant amount of hNMDAR1A mRNA but varying ratios of hNMDAR2A or hNMDAR2B mRNAs were compared. The receptors expressed at a 10:1 ratio of 2A:2B transcripts displayed an ifenprodil sensitivity that would be predicted for a population in which 51% was represented by hNMDAR(1A)2(2A)3 complexes. Our results underscore the need for subtype-selective compounds acting at novel sites to sufficiently probe the pharmacological differences between NMDA receptor subtypes formed by different subunit combinations.

Inhibition by amphetamine of testosterone secretion through a mechanism involving an increase of cyclic AMP production in rat testes

1. The effect of amphetamine on the secretion of testosterone and the production of testicular adenosine 3':5'-cyclic monophosphate (cyclic AMP) in rats was studied. 2. A single intravenous injection of amphetamine decreased the basal and human chorionic gonadotropin (hCG)-stimulated levels of plasma testosterone. Plasma LH levels were not altered by the injection of amphetamine. 3. Administration of amphetamine in vitro resulted in a dose-dependent inhibition of both basal and hCG-stimulated release of testosterone. 4. Amphetamine enhanced the basal and hCG-increased levels of cyclic AMP accumulation in vitro in rat testes. 5. These results suggest that amphetamine inhibits the spontaneous and hCG-stimulated secretion of testosterone from the testes through a mechanism involving an increase in cyclic AMP production.

Diagnostic imaging in the evaluation of dysphagia

Evaluation of dysphagia is a challenge commonly encountered by family physicians. Dysphagia may be classified as either the oropharngeal type or the esophageal type and may have a variety of etiologies. Possible causes of oropharyngeal dysphagia include Zenker's diverticulum, pharyngeal carcinoma, pharyngeal webs and strictures, lateral pharyngeal pouches and neuromuscular diseases. Esophageal dysphagia can be caused by esophageal carcinoma, esophageal stricture and webs, achalasia, diffuse esophageal spasm and scleroderma, caustic esophagitis and infectious esophagitis. Studies using different textures of barium allow evaluation of the swallowing mechanism. Static images are obtained to evaluate the integrity of the mucosa.

Late-onset idiopathic hypoparathyroidism with thymoma: a case report

A 62-year-old male was admitted because of numbness and twitching of both hands. Hypocalcemia with positive Trousseau's sign was noted. Chest X-ray and computed tomography (CT) showed an anterior mediastinal mass. Skull X-ray and whole body bone scan could not rule out bony metastasis to the left parietal bone, causing an anterior mediastinal tumor with bony metastasis to be suspected initially. Median sternotomy and extended thymectomy were done, and Stage II thymoma with negative calcitonin staining was noted. However, hypocalcemia persisted after thymectomy and the results of pre-operative and post-operative intact-parathyroid hormone (intact-PTH) were less than the detection limit (<13.3 pg/ml). Tumor markers and gallium tumor scan were all negative. Brain CT disclosed calcification over the bilateral basal ganglia and bilateral dentate nuclei of the cerebellum; the supposed metastatic osteolytic lesions of parietal bone were considered to result from pacchionion arachnoid granulation tissues. The coexistence of late-onset idiopathic hypoparathyroidism and thymoma has not been reported before. Long-term replacement therapy with vitamin D and calcium was necessary for this case.

Effect of maternal labor and mode of delivery on neutrophil actin response to N-formylmethionyl-leucyl-phenylalanine in healthy neonates

Diminished actin response to N-formyl-methionyl-leucyl-phenylalanine (FMLP) has been used to explain the impaired chemotaxis of neonatal neutrophils, but the effect of labor on this response has not been evaluated before. Therefore, we tested the hypothesis that labor stress may have an effect on actin response of cord blood neutrophils to FMLP. This response is compared by phallacidin stain of neutrophil F-actin and flow cytometry analysis among 3 groups of healthy neonates: group I, 16 vaginally delivered neonates; group II, 16 neonates delivered by elective cesarean section without labor; and group III, 16 neonates delivered by cesarean section after labor. In the group III, 10 infants were delivered by an emergency cesarean section because of fetal heart rate deceleration indicating fetal distress (one minute Apgar score < 7 in 5 cases [50%]), and the other 6 infants were delivered because of failure of progression of labor (one minute Apgar score < 7 in 2 cases [33.3%]). Stimulated relative F-actin content of neutrophils in group III was increased compared with groups I and II. There was no such difference between neutrophils from infants of groups I and II. The results of this study indicate that fetal distress may enhance neutrophil actin response to FMLP, while labor or mode of delivery might not have such effect.

Outbreak of obstructive ventilatory impairment associated with consumption of Sauropus androgynus vegetable

BACKGROUND

Forty four individuals, suffering from temporary insomnia and poor appetite followed by progressive difficulty breathing after four weeks or more ingestion of the Sauropus androgynus or Sabah vegetable, were reported to the National Poison Center of Taiwan by physicians between August 23, 1994 and August 25, 1995.

OBJECTIVE

A telephone questionnaire survey was designed and conducted to collect demographic data, information about use of the vegetable, past medical history and clinical presentation. Laboratory data were obtained from their physicians as available.

RESULTS

Forty one patients, predominantly women, 43 +/- 11 years old, were identified in our survey. They reported a variety of sources and preparation methods for the vegetable. Difficulty breathing, identified in 36 cases, was the clinical hallmark. Twenty people gave a history of dyspnea delayed until 44 +/- 40 days after discontinuing vegetable consumption. Laboratory evidence of obstructive ventilatory impairment (FEV1/FVC 56 +/- 12%, FEV1 31 +/- 6%, PaO2 71 +/- 15%) was observed in 12 cases tested. An open lung biopsy performed in a demonstration case disclosed bronchiolitis obliterans organizing pneumonia.

CONCLUSION

In this case series of 41 victims, we have identified a severe pulmonary effect and hypothesize that it is related to consumption of sauropus androgynus vegetable. Papaverine has been previously identified in this vegetable but is unlikely to be responsible for the full range of toxicity seen.

Evolutionary origins of retroposon lineages of Mhc class II Ab alleles

Major histocompatibility complex (Mhc) class II Ab genes have evolved into three distinct lineages. While lineage 2 alleles differ from lineage 1 alleles by the insertion of a retroposon in intron 2, the basis for the extremely large intron 2 in lineage 3 alleles has heretofore been undetermined. In this report, we demonstrate by nucleotide sequencing that the genomic sequences of prototypic alleles from all three lineages diverge significantly and that lineage 3 is derived from lineage 2 by two insertional events in intron 2. One insert, composed of a member of B1 short interspersed repetitive elements (SINEs), occurs 508 base pairs (bp) 3' of exon 2, and the other, 1141 bp 3' of exon 2 within the retroposon that distinguishes lineage 2 from lineage 1. To assess the evolutionary stability of these lineages and the extent of ancestral polymorphisms of Ab within Mus species, we extended our restriction site polymorphism analysis to include 86 alleles from 120 independently derived H2 haplotypes from 12 separate species and subspecies of Mus. A phylogenetic tree revealing the relationships of these Ab alleles with respect to restriction site polymorphisms, but excluding the retroposon insertions, demonstrated that these lineages have distinctive genomic structures beyond the retroposon polymorphisms. In summary, these mouse Ab genes were produced from successive retroposon insertion events. Lineage 1 and 2 were detected in a variety of Mus species, including Mus caroli, indicating that these lineages diverged more than 2 million years ago. Lineage 3 alleles were found only in the Mus musculus subspecies, suggesting that it diverged from lineage 2 more recently. These results indicate that all three lineages of Ab have persisted through several speciation events in the genus Mus.