Circumnipple-incision, longitudinal-breast dissection augmentation mammaplasty

A modification of circumnipple breast augmentation is described, which confines the minimal scar to the base of the nipple. Furthermore, a longitudinal breast parenchyma dissection is performed for breast pocket dissection that limits the injury of the lactiferous ducts and nerves to a minimum, and makes dissection and exposure of the pocket easier, even in patients whose nipples are small. This technique is especially useful in small breasts. We have performed this procedure in 57 patients, and the few complications to date are discussed in this paper.

Reactive oxygen species and substance P in monocrotaline-induced pulmonary hypertension

We attempted to evaluate whether the antioxidants 1,3-dimethyl-2-thiourea (DMTU) and hexa(sulfobutyl)fullerenes (FC(4)S) attenuate monocrotaline (MCT)-induced pulmonary hypertension (PH) by lowering lung substance P (SP) in Wistar rats. Sixty-three rats weighing 297 +/- 8 g were divided into six groups: control; MCT; capsaicin + MCT; MCT + DMTU-1; MCT + DMTU-2; and MCT + FC(4)S. Three weeks before the functional study, saline was injected into each control rat, whereas each MCT rat received 60 mg/kg sc MCT. Rats in the third group received capsaicin pretreatment followed by MCT. A 3-day injection of DMTU was performed during the early (DMTU-1) or the late (DMTU-2) post-MCT period. For the last group, each MCT-treated rat received a daily FC(4)S injection until the commencement of the functional study. Compared to the control group, MCT caused significant increases in pulmonary arterial pressure (Ppa), right ventricular hypertropy, pulmonary arterial medial thickness, lung SP level, and luminol-enhanced chemiluminescence counts in bronchoalveolar lavage. Both capsaicin and antioxidants significantly attenuated the above MCT-induced alterations. SP-induced acute increase in Ppa was exaggerated in MCT-treated rats. These results suggest that oxygen radicals play an important role in MCT-induced PH via elevating lung SP level.

Capsaicin pre- and post-treatment on rat monocrotaline pneumotoxicity

Monocrotaline (MCT) produces respiratory dysfunction, pulmonary hypertension (PH), and right ventricular hypertrophy (RVH) in rats. Tachykinins, such as substance P (SP) and neurokinin A (NKA), may mediate these effects. The purpose of this study was to investigate the length of tachykinin depletion (via capsaicin treatment) is needed to prevent (or attenuate) PH and/or RVH. Six groups of rats were injected subcutaneously with saline (3 ml/kg); capsaicin followed by saline or MCT (60 mg/kg); or MCT followed 7, 11, or 14 days later by capsaicin. Capsaicin (cumulative dose, 500 mg/kg) was given over a period of 4-5 days. Respiratory function, pulmonary vascular parameters, lung tachykinin levels, and tracheal neutral endopeptidase (NEP) activity were measured 21 days after MCT or saline injection. Capsaicin significantly decreased lung levels of SP but not NKA. Both capsaicin pretreatment and posttreatment blocked the following MCT-induced alterations: increases in lung SP and airway constriction; decreases in tracheal NEP activity and dynamic respiratory compliance. Administration of capsaicin before or 7 days after MCT blocked MCT-induced PH and RVH. The above data suggest that the early tachykinin-mediated airway dysfunction requires only transient elevated tachykinins, while progression of late tachykinin-mediated effects (PH and RVH) requires elevated tachykinins for more than one week.

Identifying attitudinal barriers to family management of cancer pain in palliative care in Taiwan

The purpose of this study was threefold: (1) to examine attitudes held by Taiwanese family caregivers of hospice inpatients with cancer that serve as barriers to cancer pain management; (2) to determine the relationship of attitudinal barriers to family caregiver hesitancy to report pain and to administer analgesics; and (3) to determine the relationship of attitudinal barriers to the adequacy of analgesics used by the patient. A total of 80 pairs of palliative care inpatients and their primary family caregivers participated in this study. Family caregivers completed the Barriers Questionnaire-Taiwan (BQT) form and a demographic questionnaire. The instruments completed by patients consisted of the Brief Pain Inventory-Chinese version and a demographic questionnaire. The data revealed that Taiwanese family caregivers of palliative care patients with advanced cancer had concerns about reporting pain and administering analgesics, particularly as they related to disease progression, side-effects and p.r.n. analgesics. Older and less-educated family caregivers scored significantly higher on the BQT than did their younger, more educated counterparts. Family caregivers' concerns measured by the BQT were related to family caregivers' reluctance to administer analgesics to their patients. Implications for a broader understanding of analgesics in the advancement of pain management in palliative care in Taiwan are discussed.

Contributing factors of mandibular deformation during mouth opening

OBJECTIVES

A decrease in mandibular arch width during forced opening has been documented. However, the contributing factors of mandibular deformations are still unclear. This study investigated the mandibular deformation during mouth opening, and searched for contributing factors related to this phenomenon.

METHODS

Sixty-two dental students volunteered for this study. A linear variable differential transducer (LVDT) was cemented on the mandibular first molars to record mandibular deformation during mouth opening. Proposed factors including geometric factors of the mandible such as lower gonial angle, mandibular length, symphyseal width and height were measured from cephalometric analysis. Densitometric analysis was performed to detect symphyseal area and bone density.

RESULTS

The changes in width between the mandibular first molars ranged from 20 to 437 microm, which was negatively correlated to the symphyseal width, area, and bone density. Where the lower gonial angle had a positive influence, the arch width changed during mouth opening. A multifactorial model showed a significant correlation between the set of predictor variables (symphyseal area, bone density, and mandibular length) and mandibular deformation.

CONCLUSIONS

Mandibular arch width narrowed during forced opening. Subjects with smaller symphysis, lower bone density and longer mandible tend to have larger arch width changes.

Mediators and oxygen radicals in hyperpnea-induced airway constriction of guinea pigs

Leukotrienes (LTs), tachykinins (TKs), and oxygen radicals have been suggested to be important modulating factors for the hyperpnea-induced bronchoconstriction (HIB) of guinea pigs. In this study, we tested the hypothesis that LTs and oxygen radicals modulate HIB by triggering TK release. Eighty-five Hartley guinea pigs were divided into four groups: control, dimethylthiourea (DMTU), FPL 55712, and A63162. DMTU is the scavenger for hydroxyl radical. FPL 55712 is an antagonist of LT receptor, whereas A63162 is an inhibitor of lipoxygenase. Each group was further divided into three subgroups: baseline, hyperpnea, and recovery. Each animal was anesthetized, cannulated, paralyzed, and artificially ventilated. We measured dynamic respiratory compliance (Crs), maximal expiratory flow at 50% total lung capacity (V(max(50))), and forced expiratory volume in 0.1 s (FEV(0.1)) during the baseline and recovery periods. Hyperpnea caused significant decreases in Crs, V(max(50)), and FEV(0. 1), indicating HIB in the control group. Pretreatment with DMTU, FPL 5712, or A63162 attenuated HIB. Plasma substance P (SP) levels increased progressively during the experiment in all groups. However, both FPL 55712 and A63162, but not DMTU, significantly decreased SP levels. Similarly, lung malondialdehyde (MDA) contents increased progressively during the experiment in the control group. Neither FPL 55712 nor A63162 significantly affected the increase. On the contrary, DMTU significantly attenuated the increase in MDA during the recovery period. These results suggest that inhibition of LTs leads to suppression at SP levels and HIB, whereas DMTU attenuates HIB by means of other mechanisms.

Native and oxidized low-density lipoproteins enhance superoxide production from diabetic rat glomeruli

Oxygen free radicals have been implicated in mediating diabetic complications, and patients with diabetic nephropathy frequently show increased levels of circulating and oxidized low-density lipoproteins (LDL). In the present study, we measured the superoxide production of glomeruli isolated from poorly controlled diabetic (streptozotocin) rats sacrificed 1 week and 1, and 3 months after the induction of diabetes. The animals were stimulated with native and oxidized LDL isolated from normal humans with normolipidemia. The superoxide ion was measured by using a spectrophotometer. The results demonstrated that the poorly controlled diabetic rat glomeruli showed a significantly higher production of superoxide than normal glomeruli under basal conditions, and this production increased further with the progression of diabetes. Stimulation with either LDL or oxidized LDL enhanced superoxide production by diabetic glomeruli, with oxidized LDL being more potent than LDL. Our results suggest that oxidized LDL may play important roles in the pathogenesis of diabetic nephropathy through enhanced generation of oxygen free radicals.

Wood smoke-induced airway hyperreactivity in guinea pigs: time course, and role of leukotrienes and hydroxyl radical

A prior airway exposure to wood smoke induces a tachykinin-dependent increase in airway responsiveness to the subsequent smoke inhalation in guinea pigs (Life Sci. 63: 1513, 1998). To further investigate the time course of, and the contribution of other chemical mediators to, this smoke-induced airway hyperresponsiveness (SIAHR), two smoke challenges (each 10 ml) separated by 30 min were delivered into the lungs of anesthetized guinea pigs by a respirator. In the control animals, the SIAHR was evidenced by the bronchoconstrictive response to the second smoke challenge (SM2) which was approximately 5.2-fold greater than that to the first challenge (SM1). This SIAHR was alleviated by shortening the elapsed time between SM1 and SM2 to 10 min or by extending it to 60 min, and was abolished by extending it to 120 min. This SIAHR was reduced by pretreatment with either MK-571 (a leukotriene D4-receptor antagonist) or dimethylthiourea (a hydroxyl radical scavenger), but was not affected by pretreatment with either pyrilamine (a histamine H1-receptor antagonist) or indomethacin (a cyclooxygenase inhibitor). The smoke-induced reduction in the neutral endopeptidase activity (a major enzyme for tachykinin degradation) measured in airway tissues excised 30 min post SM1 was largely prevented by pretreatment with dimethylthiourea. However, this reduction was not seen in airway tissues excised 120 min post SM1. These results suggest that 1) the SIAHR to inhaled wood smoke has a rapid onset time following smoke inhalation and lasts for less than two hours, 2) leukotrienes and hydroxyl radical may play contributory roles in the development of this SIAHR, and 3) hydroxyl radical is the major factor responsible for the smoke-induced inactivation of airway neutral endopeptidase, which may possibly participate in the development of this SIAHR.

Respiratory mechanics and maximal expiratory flow in the anesthetized mouse

Mice have been widely used in immunologic and other research to study the influence of different diseases on the lungs. However, the respiratory mechanical properties of the mouse are not clear. This study extended the methodology of measuring respiratory mechanics of anesthetized rats and guinea pigs and applied it to the mouse. First, we performed static pressure-volume and maximal expiratory flow-volume curves in 10 anesthetized paralyzed C57BL/6 mice. Second, in 10 mice, we measured dynamic respiratory compliance, forced expiratory volume in 0.1 s, and maximal expiratory flow before and after methacholine challenge. Averaged total lung capacity and functional residual capacity were 1.05 +/- 0.04 and 0.25 +/- 0.01 ml, respectively, in 20 mice weighing 22.2 +/- 0.4 g. The chest wall was very compliant. In terms of vital capacity (VC) per second, maximal expiratory flow values were 13.5, 8.0, and 2.8 VC/s at 75, 50, and 25% VC, respectively. Maximal flow-static pressure curves were relatively linear up to pressure equal to 9 cm H(2)O. In addition, methacholine challenge caused significant decreases in respiratory compliance, forced expiratory volume in 0.1 s, and maximal expiratory flow, indicating marked airway constriction. We conclude that respiratory mechanical parameters of mice (after normalization with body weight) are similar to those of guinea pigs and rats and that forced expiratory maneuver is a useful technique to detect airway constriction in this species.

Retentive and compressive strengths of modified zinc oxide-eugenol cements

OBJECTIVES

This investigation sought to improve the handling and physical properties of a commonly used temporary zinc oxide-eugenol cement by changing the base/accelerator (B/A) ratio or combining it with a petroleum jelly or fluoride varnish.

METHODS

Twelve modifications of a temporary cement were evaluated in terms of retentive strength, compressive strength at 24 h, film thickness and by scanning electron microscopy.

RESULTS

Decreasing the B/A mixing ratio increased the retentive and compressive strengths, but reduced the film thickness of the cement. By increasing the percentage of incorporated petroleum jelly or fluoride varnish in the cement, there was a progressive decrease in the retentive and compressive strengths and in film thickness.

CONCLUSIONS

Modifications of a zinc oxide-eugenol temporary cement to change the B/A ratio or to incorporate additives resulted in variations in physical properties. All modified forms of the cement had a film thickness less than 25 microns and a compressive strength below 35 MPa. With a wide range of retentive strength, modified forms of zinc oxide-eugenol cement may be found to have diverse clinical applications.

Cough threshold in people with spinal cord injuries

BACKGROUND AND PURPOSE

The purpose of this study was to compare the cough threshold between people with and without spinal cord injury (SCI). The effect of smoking on cough threshold was also investigated.

SUBJECTS

The participants were 26 people with SCI (15 smokers, 11 nonsmokers) and 18 people without SCI (9 smokers, 9 nonsmokers).

METHODS

Aerosols of citric acid were delivered with incremental doubling concentration from 62.5 mmol to 2 mol. Cough threshold was defined as the first concentration of citric acid that induced at least 2 coughs, which is associated with large chest excursion and concurrently acoustic response.

RESULTS

The mean cough thresholds of smokers and nonsmokers with SCI (209 and 417 mmol, respectively) were lower than those of smokers and nonsmokers without SCI (467 and 1,072 mmol, respectively). The mean citric acid cough thresholds decreased in smokers with and without SCI when compared with nonsmokers with and without SCI.

CONCLUSION AND DISCUSSION

The cough sensitivity increased in subjects with SCI, and smoking could also increase the cough sensitivity. Training about the frequency and technique of cough in patients with SCI should be carefully monitored.

Mediators in hyperpnea-induced bronchoconstriction of guinea pigs

Both tachykinins and leukotrienes (LTs) have been demonstrated to be the mediators for hyperpnea-induced bronchoconstriction (HIB) of guinea pigs. We tested the hypothesis that leukotrienes modulate HIB indirectly by triggering tachykinin release. Ninety nine young guinea pigs were divided into four groups: control; LTC4; FPL 55712 (a LT receptor antagonist); and MK-886 (an inhibitor of LT synthesis). Each animal was anesthetized, cannulated, paralyzed, and artificially ventilated. The protocol included the baseline, hyperpnea, and recovery periods. Thus, animals in each group were further divided into three subgroups: baseline; recovery-3 min; and recovery-8 min. We measured dynamic respiratory compliance (Crs), forced expiratory volume in 0.1 s (FEV0.1) and maximal expiratory flow at 30% total lung capacity (Vmax30), as well as determined substance P (SP) and LT levels in plasma and bronchoalveolar lavage (BAL) during either the baseline or the recovery (3 or 8 min) period. Hyperpnea caused decreases in Crs, FEV0.1 and Vmax30, indicating HIB, in the control group at 3 min and 8 min of the recovery period. Both FPL 55712 and MK-886 significantly attenuated HIB. In the control group, hyperpnea caused significant increases in SP and LT levels in both plasma and BAL. These increases in SP levels were significantly suppressed, however, by FPL 55712 and MK-886. Compared to the control group, infusion of LTC4 did not significantly alter either HIB, SP or LT levels in most cases. An additional group of 24 animals treated with neurokinin-2 receptor antagonist, SR 48968, demonstrated that SR 48968 significantly suppressed hyperpnea-induced increases in plasma, but not in BAL, LT levels. Since FPL 55712 and MK-886 first suppress LT activities, these results suggest that suppressed LT activities attenuate HIB indirectly via reducing tachykinin release.

The relationship between placental histology and cervical ultrasonography in women at risk for pregnancy loss and spontaneous preterm birth

OBJECTIVE

Our objective was to determine whether there were any differences in the placental lesions of high-risk patients with versus without ultrasonographic evidence of cervical shortening between 15 and 24 weeks' gestation.

STUDY DESIGN

Women who were at risk for pregnancy loss and spontaneous preterm birth were followed by serial transvaginal cervical ultrasonography with transfundal pressure between 15 and 24 weeks' gestation. Two groups of women were identified: those in whom progressive cervical shortening developed to below 2 cm, either spontaneously or induced by transfundal pressure, and those in whom it did not. A perinatal pathologist who was blinded to the pregnancy outcome retrospectively examined placental histologic slides. The histologic placental lesions were categorized as acute or chronic inflammatory lesions, decidual vascular lesions, and coagulation-related lesions.

RESULTS

There were 278 women who were followed during the study. Placentas were submitted for histologic examination in 189 cases (125 singleton, 45 twin, and 19 triplet gestations). There were 72 pregnancies with and 117 pregnancies without an ultrasonographic diagnosis of cervical shortening, respectively. Overall, there were significantly more acute inflammatory lesions in patients in whom cervical shortening developed, as determined by ultrasonographic examination. However, there were significantly more decidual vascular lesions in women in whom cervical shortening did not develop. When we examined the distribution of the placental histologic lesions in the 64 cases of multiple gestations, the only significant finding was again a greater frequency of acute inflammatory lesions in patients in whom cervical shortening developed. There was no difference in the distribution of the placental histologic lesion categories among women treated with bed rest versus cervical cerclage because of the ultrasound diagnosis of cervical shortening.

CONCLUSION

Acute inflammatory lesions of the placenta were more frequent in patients with second-trimester cervical shortening. These findings support that patients with cervical shortening in the second trimester are prone to acute placental inflammation.

Breast reconstruction following excision of phylloides tumor

There are few papers published on breast reconstruction after excision of phylloides tumor. Six patients who had reconstruction of the breast following excision of phylloides tumor are described. All underwent wide excision or subcutaneous mastectomy followed by immediate or delayed reconstruction with implants or autologous tissue. The mean follow-up was 5 years (range, 2.5-7 years). One patient died of metastases; the others survived without evidence of recurrence. The etiology, incidence, diagnosis, and treatment of these tumors are discussed. The aesthetic results in these patients is also described.

The effect of tetrandrine and extracts of Centella asiatica on acute radiation dermatitis in rats

Radiation injury to the skin is one of the major limiting factors in radiotherapy. We designed this study using Sprague-Dawley rats to evaluate the reduction in skin injury achieved using natural products from plant extracts as protection. The acute skin reaction in tetrandrine- and Madecassol-treated animals appeared earlier, but was significantly less severe, than in the control group. The peak skin reactions in the tetrandrine group were less serious than those of the control group at three different radiation doses. At a high dose irradiation, the healing effect of tetrandrine is better than Madecassol and vaseline. The histologic findings indicate that tetrandrine and Madecassol are able to reduce acute radiation reactions by their anti-inflammatory activity.

Vulvovaginal reconstruction following radical tumor resection: report of 12 cases

BACKGROUND

The absence of the vulva and vagina is a distressful problem, especially for the sexual life of a woman. The potential benefit associated with the use of various vaginal reconstructive methods was studied.

METHODS

Between April 1987, and June 1997, 12 patients undergoing gynecologic carcinoma surgery were treated with simultaneous vulvovaginal reconstruction using local labia majora flaps (1), gracilis myocutaneous flaps (3), and innervated pudendal-thigh flaps (8).

RESULTS

The mean follow-up period was 32 months. There were no major surgical complications, with the exception of one patient who had a ureteroileal fistula after bilateral gracilis myocutaneous flap reconstruction and radiotherapy. One patient received pelvic radiation after bilateral gracilis myocutaneous flap reconstruction, and the complication of perineal bleeding occurred 90 days after the vaginal reconstruction. Another patient had introital stenosis of the neovagina after reconstruction using bilateral labia majora flaps. Seven patients had regular and satisfactory sexual lives. These patients were all treated by innervated pudendal-thigh flap reconstruction.

CONCLUSION

The innervated pudendal-thigh flap provides a sensitized flap for reconstruction of the vulva and vagina following vulvovaginal carcinoma surgery. For extended carcinoma with vulvovaginal involvement, the gracilis myocutaneous flap is would be better for reconstruction of a large defect.

Maternal chorioamnionitis and umbilical vein interleukin-6 levels for identifying early neonatal sepsis

OBJECTIVE

The purpose of this study was to determine whether elevated levels of umbilical vein IL-6 would be a better marker for early neonatal sepsis than the clinical signs of maternal chorioamnionitis.

METHODS

Patients delivering preterm because of spontaneous preterm labor or premature rupture of the membranes were evaluated for clinical signs of chorioamnionitis, which was defined as a temperature of > or =100.4 degrees F along with > or =2 of the following: significant maternal tachycardia (> or = 120 bpm), fetal tachycardia (> or =160 bpm), purulent discharge, uterine tenderness, and leukocytosis (WBC > or =18,000 cells/mm3). Umbilical vein blood was assayed for interleukin-6. An elevated interleukin-6 level was determined to be 25 pg/mL. Infants were evaluated for evidence of early neonatal sepsis. The abilities of clinical chorioamnionitis and interleukin-6 levels > or =25 pg/mL to predict early neonatal sepsis were compared.

RESULTS

There were 28 patients delivering 14 (50%) neonates with evidence for early neonatal sepsis. The incidence of suspected neonatal sepsis in women with and without clinical chorioamnionitis was 6/10 (60%) vs. 8/18 (44.4%), P = 0.43. Using receiver operator characteristic curves, the best cutoff for interleukin-6 was found to be 25 pg/mL. The compared sensitivity, specificity, and positive and negative predictive values of clinical chorioamnionitis vs. interleukin-6 levels > or =25 pg/mL for predicting early neonatal sepsis were 42.9% vs. 92.9%, 71.4% vs. 92.9%, 60% vs. 92.9%, and 55.6% vs. 92.9%, respectively.

CONCLUSIONS

Elevated umbilical vein levels of interleukin-6 predict those preterm infants with early sepsis better than the presence of clinical chorioamnionitis.

Chronic activation of neurokinin-1 receptor induces pulmonary hypertension in rats

In this study we explored the hypothesis that chronic activation of neurokinin-1 (NK-1) receptor induces pulmonary hypertension in Wistar rats. First, the activation of NK-1 receptor on the pulmonary circulation was investigated by use of a chronic injection of NK-1 agonist [Ser9,Met(O2)11]-substance P (1 x 10(-9) mol/kg) for 2 wk at sea level (rats breathed room air) and during hypoxia (rats were placed in a hypobaric 380-Torr chamber). Second, we studied the effect of NK-1 antagonist (CP-96345) on developing and developed (after 4 wk of chronic hypoxia) pulmonary hypertension. Pulmonary arterial pressure, the weight ratio of right ventricle to left ventricle + septum, hematocrit, and substance P (SP) were measured. We found that NK-1 agonist significantly increased pulmonary arterial pressure in the sea-level but not in the hypoxic group. However, NK-1 agonist induced neither right heart hypertrophy nor polycythemia. CP-96345 significantly decreased pulmonary arterial pressure in the hypoxic group but had no effect in the sea-level group. Furthermore, CP-96345 significantly attenuated the acute SP-induced increase in pulmonary arterial pressure in the sea-level and hypoxic groups, with a larger increase in the hypoxic group. These results suggest that chronic activation of NK-1 receptor induces pulmonary hypertension and that there is an increase in the sensitivity of pulmonary vessels in response to SP in chronically hypoxic rats.

Laparoscopically assisted full thickness skin graft for reconstruction in congenital agenesis of vagina and uterine cervix

In patients with agenesis of the vagina and cervix but with a functional endometrium, the traditional treatment is hysterectomy with construction of a neovagina. We report successful treatment by laparoscopically assisted full thickness skin graft for reconstruction in a patient with congenital agenesis of the vagina and uterine cervix concomitant with haematometra and ovarian endometrioma in a 12 year old girl. Postoperatively, the vaginal skin graft healed well, and menstruation first appeared 4 weeks later. In our opinion, a combined laparoscopic and vaginal procedure with full thickness skin graft is an efficacious alternative in managing such genital defects.

Roles of oxygen radicals and elastase in citric acid-induced airway constriction of guinea-pigs

Antioxidants attenuate noncholinergic airway constriction. To further investigate the relationship between tachykinin-mediated airway constriction and oxygen radicals, we explored citric acid-induced bronchial constriction in 48 young Hartley strain guinea-pigs, divided into six groups: control; citric acid; hexa(sulphobutyl)fullerenes + citric acid; hexa(sulphobutyl)fullerenes + phosphoramidon + citric acid; dimethylthiourea (DMTU) + citric acid; and DMTU + phosphoramidon + citric acid. Hexa(sulphobutyl)fullerenes and DMTU are scavengers of oxygen radicals while phosphoramidon is an inhibitor of the major degradation enzyme for tachykinins. Animals were anaesthetized, paralyzed, and artificially ventilated. Each animal was given 50 breaths of 4 ml saline or citric acid aerosol. We measured dynamic respiratory compliance (Crs), forced expiratory volume in 0.1 (FEV0.1), and maximal expiratory flow at 30% total lung capacity (Vmax30) to evaluate the degree of airway constriction. Citric acid, but not saline, aerosol inhalation caused marked decreases in Crs, FEV0.1 and Vmax30, indicating marked airway constriction. This constriction was significantly attenuated by either hexa(sulphobutyl)fullerenes or by DMTU. In addition, phosphoramidon significantly reversed the attenuating action of hexa(sulphobutyl)fullerenes, but not that of DMTU. Citric acid aerosol inhalation caused increases in both lucigenin- and t-butyl hydroperoxide-initiated chemiluminescence counts, indicating citric acid-induced increase in oxygen radicals and decrease in antioxidants in bronchoalveolar lavage fluid. These alterations were significantly suppressed by either hexa(sulphobutyl)fullerenes or DMTU. An elastase inhibitor eglin-c also significantly attenuated citric acid-induced airway constriction, indicating the contributing role of elastase in this type of constriction. We conclude that both oxygen radicals and elastase play an important role in tachykinin-mediated, citric acid-induced airway constriction.

Smoke-induced airway hyperresponsiveness to inhaled wood smoke in guinea pigs: tachykininergic and cholinergic mechanisms

The smoke-induced airway hyperresponsiveness (SIAHR) to inhaled wood smoke was investigated in anesthetized guinea pigs. Two smoke challenges (each 10 ml) separated by 30 min were delivered into the lungs by a respirator. In control animals, SIAHR was evidenced by an average bronchoconstrictive response (an increase in total lung resistance) to the second smoke challenge (SM2) that was approximately 4.3-fold greater than that to the first challenge (SM1). Pretreatment with CP-96,345 and SR-48,968 (neurokinin-1 and -2 receptor antagonists; each 1 mg/kg) in combination totally prevented this SIAHR, while pretreatment with CP-96,344 and SR48,965 (inactive enantiomers of CP-96,345 and SR-48,968, each 1 mg/kg) in combination failed to do so. Pretreatment with CP-96,345 (1 mg/kg), SR48,968 (1 mg/kg), or atropine (50 microg/kg) significantly alleviated this SIAHR. Pretreatment with phosphoramidon [an inhibitor of neutral endopeptidase (NEP); 2 mg/kg], which suppresses the degradation of tachykinins, induced an increase in airway reactivity that largely mimicked this SIAHR. The NEP activity measured in airway tissues excised 30 min after SM1 was significantly lower than that in air control value. These results suggest that 1) a prior wood smoke exposure induces an airway hyperresponsiveness to the subsequent wood smoke inhalation, 2) a tachykininergic mechanism involving both neurokinin-1 and -2 receptors is essential for, and a cholinergic mechanism is also involved in the development of this SIAHR, and 3) inactivation of airway NEP by wood smoke may contribute to this SIAHR.

Acetylcholine and tachykinin receptor antagonists attenuate wood smoke-induced bronchoconstriction in guinea pigs

To study the mechanisms of wood smoke-induced bronchoconstriction, we measured total lung resistance (RL) and dynamic lung compliance (Cdyn) in anesthetized and mechanically ventilated guinea pigs. Airway exposure to various doses of wood smoke (lauan wood; 5, 10, and 15 breaths) resulted in a dose-dependent increase in RL and decrease in Cdyn. The smoke-induced changes in RL and Cdyn were significantly attenuated by pretreatment with atropine, CP-96,345 [(2S,3S)-cis-2-(diphenylmethyl)-N-((2-methoxyphenyl)-methyl)-1-aza bicyclo(2.2.2.)-octan-3-amine; a tachykinin NK1 receptor antagonist], and SR-48,968 [(S)-N-methyl-N(4-(4-acetylamino-4-phenylpiperidino)-2-(3,4-dichlorophen yl)-butyl)benzamide; a tachykinin NK2 receptor antagonist] in combination, atropine alone, and SR-48,968 alone, but were not significantly affected by pretreatment with the inactive enantiomers of CP-96,345 and SR-48,968, CP-96,345 alone, indomethacin (a cyclooxygenase inhibitor), and MK-571 [((3-(3-(2-(7-chloro-2-quinolinyl)ethenyl)phenyl((3-dimethyl amino-3-oxo-propyl)thio)methyl)propanoic acid; a leukotriene D4 receptor antagonist]. The activity of airway neutral endopeptidase, a major enzyme for tachykinin degradation, was not significantly influenced by wood smoke during the development of bronchoconstriction. We conclude that: (1) both cholinergic mechanisms and endogenous tachykinins, but not cyclooxygenase products or leukotriene D4, play an important role in the acute bronchoconstriction induced by wood smoke, and (2) the contribution of tachykinins to this airway response is primarily mediated via the activation of tachykinin NK2 receptors, but is not associated with inactivation of the airway neutral endopeptidase.

Antioxidants attenuate chronic hypoxic pulmonary hypertension

Because chronic hypoxia increases the production of oxygen radicals, we hypothesized that antioxidants attenuate chronic hypoxic pulmonary hypertension. In part 1, we examined the temporal progress in chronic hypoxic pulmonary hypertension in 46 Wistar rats exposed to hypoxia from 0-3 weeks. In part 2, we tested whether antioxidants attenuated chronic hypoxic pulmonary hypertension in 82 rats divided into 10 groups: control, fullerenol-1, U-83836E, dimethylthiourea-1, dimethylthiourea-2, hypoxia, hypoxia + fullerenol-1, hypoxia + U83836E, hypoxia + dimethylthiourea-1, and hypoxia + dimethylthiourea-2. Control animals breathed room air and were injected intraperitoneally with saline for 2 weeks. Fullerenol-1, U-83836E, and dimethylthiourea are antioxidants and were administered intraperitoneally for 2 weeks, except that dimethylthiourea was given either on days 3, 5, and 7 (dimethylthiourea-1), or on days 8, 10, and 12 (dimethylthiourea-2). Hypoxic animals were placed into a hypobaric chamber with a barometric pressure of 380 Torr for 2 weeks. Hypoxia + antioxidant groups were administered antioxidants during hypoxic exposure. We observed a gradual increase in pulmonary artery pressure, the weight ratio of right ventricle to left ventricle plus septum, and hematocrit during the 3 weeks of chronic hypoxia. These hypoxia-induced alterations were significantly attenuated by U-83836E and dimethylthiourea, but not by fullerenol-1. Neither the temporal alterations nor the antioxidant effects can be explained by the change in either tracheal neutral endopeptidase activity or the lung or plasma substance P level, perhaps because of the time lag in sampling. These results indicate that oxygen radicals play an important role in the development of chronic hypoxic pulmonary hypertension.

Elastase in hyperpnea-induced guinea pig airway constriction

Aerosolized elastase has been shown to produce airway constriction in guinea pigs. In this study, we examined whether endogenous elastase plays a role in isocapnic hyperpnea-induced airway constriction using an elastase inhibitor, eglin-c. The study was divided into three experiments. In the first experiment, we used an elastase inhibitor, eglin-c, to suppress hyperpnea-induced bronchoconstriction. Twenty-two young male Hartley guinea pigs were divided into three groups: control (n=8), eglin-c(1) (a lower dose of eglin-c, n=7), and eglin-c(2) (a higher dose of eglin-c, n=7). In the second experiment, we tested whether eglin-c affects pulmonary function following 15 min of normal air ventilation in two groups of animals: control (n=8) and eglin-c (n=8). In the third experiment, animals were divided into two groups: control (n=7) and compound 48/80 (a mast cell degranulating agent, n=7). Airway function was examined in the anesthetized-paralyzed animal. In the first and third experiments, 15 min of isocapnic hyperpnea caused marked decreases in dynamic respiratory compliance, forced expiratory flow at 0.1 s and maximal expiratory flow at 50% total lung capacity, demonstrating hyperpnea-induced airway constriction. This bronchoconstriction was significantly attenuated by eglin-c and by pretreatment with compound 48/80. In the second experiment, eglin-c did not significantly affect bronchial function following normal air ventilation. These data suggest that elastase released from mast cells directly or indirectly induces hyperpnea-induced bronchoconstriction.

The role of the inhibitory nonadrenergic noncholinergic system in antigen-induced pulmonary hypersensitivity

To study the role of the inhibitory nonadrenergic noncholinergic (i-NANC) system in regulating bronchial reactivity during antigen challenge, we first tested a blocker of the i-NANC system (oxyhemoglobin, HbO2, 2.5 microm) on the relaxation response of guinea pig tracheal strips (n=6) in vitro to electrical field stimulation (ES) in the presence of atropine (1 microg/ml) and propranolol (2 microg/ml). Fresh HbO2 significantly inhibited 35.3+/-4.5% (P<0.001) of the NANC relaxation response. Secondary, 26 anesthetized, ovalbumin-sensitized animals were divided into three groups: antigen challenged (n=10), pretreated with HbO2 (13 mg/kg) and challenged (n=9), and treated with HbO2 only (n=7). Pulmonary resistance (RL) and dynamic compliance (Cdyn) were measured 15-20 min prior to (baseline) and up to 30 min after antigen or HbO2 injection. Antigen challenge alone induced early maximal respiratory changes: RL increased 1646+/-115% above baseline (2 min) whereas Cdyn decreased 42+/-10% below baseline (4 min). These changes returned to baseline within 15 min. Pretreatment with HbO2 increased peak respiratory responses induced by antigen [RL, 3728+/-1680% above baseline; Cdyn, 69+/-7% below baseline (P<0.05)]. HbO2 delayed significantly (P<0.05) the time for recovery of RL and Cdyn. HbO2 alone had little effect on respiratory parameters. We conclude that HbO2 may antagonize the i-NANC system in the airway and this antagonism may accentuate pulmonary hypersensitivity during acute antigen challenge.