The antral follicle count predicts the outcome of pregnancy in a controlled ovarian hyperstimulation/intrauterine insemination program

PURPOSE

Our purpose was to test whether age-related changes in antral follicle counts can predict the pregnancy outcome in the early follicular phase of a controlled ovarian hyperstimulation/intrauterine insemination (COH/IUI) program.

METHODS

A selected group of 107 women (36 healthy women requesting child sex preselection, 52 women with unexplained infertility, and 19 with minimal endometriosis) who underwent controlled ovarian hyperstimulation with clomiphene citrate (CC) plus human menopausal gonadotrophin (hMG) and subsequent intrauterine insemination were enrolled in the study. Transvaginal ultrasonography (7.0 MHz) was used to determine the total number of antral follicles (2-8 mm) in the right and left ovaries. The association among the antral follicle count, age, dominant follicle, and estradiol (E2) level on the day of human chorionic gonadotropin (hCG) was analyzed. The association of the pregnancy rate and OHSS with the antral follicle count, dominant follicle count, and age was also examined.

RESULTS

The total antral follicle number decreased with age (P < 0.0001). Dominant follicle number increased with total antral follicle number in women who received CC plus hMG/ IUI(P < 0.0001). The pregnant group had a higher number of antral follicle and dominant follicles in comparison with the nonpregnant group (P < 0.01 and P < 0.02, respectively). The E2 level on the day of hCG injection increased positively with the total number of antral follicles (P < 0.0001) and the total number of dominant follicles (P < 0.0001). In women aged younger than 35 years, the pregnancy rate and dominant follicle number rose as the number of antral follicles increased (P < 0.03 and P < 0.0001, respectively). The pregnancy rate was low (2/39) in women aged older than 35 years regardless of the number of antral follicles (P < 0.05) and the extent of hMG administration (P < 0.02). Women aged older than 35 also produced fewer dominant follicles (P < 0.001). No pregnancy was achieved in a patient with an antral follicle number of less than five (17 cases).

CONCLUSIONS

Age-related changes in antral follicle count significantly predicted the dominant follicle count and the pregnancy outcome. In women with antral follicle counts of less than five or who are older than 35 years, the application of COH/IUI may not be indicated.

Interleukin-1 in ischemia-reperfusion acute lung injury

Interleukin-1 (IL-1) is a proinflammatory cytokine produced by blood-borne and resident inflammatory lung tissue involved in the thrombotic occlusion of the pulmonary microcirculation and the increase of the vascular permeability following a wide variety of injuries and sepsis. The locally accentuated, organ-related activation of this cytokine seems to be responsible for the development of acute lung injury. The present study was conducted to determine if IL-1beta was produced in an ischemia-reperfusion (I/R) rat model subjected to lung injury. We measured sequential perfusate levels of IL-1beta by ELISA and we measured IL-1 gene expression in the rat lung tissue by a reverse-transcriptase polymerase chain reaction method. Little IL-1beta gene expression was observed in normal rat lung tissue. Perfusate IL-1beta slightly increased 2 h after induced ischemia and 3 h after reperfusion. IL-1beta gene expression rapidly increased as early as 30 min after ischemia and continued to increase for up to 120 min. IL-1beta gene expression was dramatically upregulated during reperfusion after cessation of ischemia, reached a peak at 1 h, and then gradually decreased (2 to 3 h) to near baseline levels. During ischemia, the increased IL-1 gene expression was not significantly different between the ventral and dorsal sites of the lung. However, IL-1 gene expression markedly increased on the dorsal part (the dependent site for a rat in a supine position) after reperfusion. From these results, it appears that IL-1 may have an important role in I/R lung injury.

Dibutyryl cAMP prevents increased vascular permeability caused by air embolism in isolated rat lungs

BACKGROUND AND HYPOTHESIS

Venous gas bubbles are routinely detected in astronauts undergoing extravehicular activities at lower suit pressure. Venous air embolism increases the pulmonary arterial pressure and the vascular permeability leading to acute lung injury. In the present study we evaluated the protective effect of dibutyryl cAMP, aminophylline, and pentoxifylline on the pulmonary vasculatures after air embolism.

METHOD

In isolated and perfused rat lungs, we induced air embolism by introducing air bubbles into the pulmonary artery. We measured the pulmonary arterial pressures and capillary pressure. Vascular permeability was determined by measuring the filtration coefficient (Kf) and the protein concentration in the lung lavage fluid.

RESULTS

Air infusion caused pulmonary hypertension and increased vascular permeability, resulting in pulmonary edema. The Kf (in g.min-1.cm H2O-1.100 g-1) increased from 0.44 +/- 0.05 at baseline to 2.98 +/- 0.47 after air infusion. Pretreatment with DBcAMP prevented the increase in Kf (0.63 +/- 0.09) caused by air embolism without altering the hemodynamics. Aminophylline and pentoxifylline did not prevent lung injury induced by air embolism. Although aminophylline did not alter the response of pulmonary arterial pressure to air infusion, it elevated the capillary pressure to 5.1 +/- 0.4 mmHg, which was significantly greater than that in the lung receiving air infusion alone.

CONCLUSION

Our results suggest that DBcAMP prevents the increase in vascular permeability caused air embolism. The ineffectiveness of aminophylline and pentoxifylline on the prevention of air embolism-induced lung injury remains for further investigation.

Cardiac tamponade in Taiwan

We retrospectively reviewed all of the patients who were treated for cardiac tamponade at Linkou Chang Gung Memorial Hospital between January 1991 and December 1995. There were a total of 112 patients (57 males, 55 females) with a mean age of 51 +/- 14 years (53 +/- 15, 49 +/- 13, respectively). Dyspnea was the most common complaint (85%). The mean blood pressure was 129 +/- 24/78 +/- 17 mmHg, and only 8% had a systolic blood pressure of less than 90 mmHg. Sinus tachycardia was the most frequent electrocardiographic finding (72%, 62/86). Diffuse low voltage was noted in 35% (30/86) of the patients and electrical alternans was seen in 17% (15/86). The mean volume of pericardial effusion was 610 +/- 263 ml. Sixty-five percent of the pericardial effusions were bloody, 31% were serosanguineous, 2% were purulent and 2% were chylous. Overall, 54.5% of the patients had malignant diseases. Of the 61 patients who died, 79% had malignancies. Thirty-five (57%) of these 48 patients had lung cancer. The mean survival time from emergent pericardiocentesis was 3.4 months. In conclusion, non-traumatic cardiac tamponade had a poor prognosis because most patients had malignant etiologies. There is still no definitive treatment for recurrent malignant pericardial effusion-induced cardiac tamponade. Percutaneous pericardiocentesis as clinically required may be the most appropriate treatment, since it is questionable whether such subjects should be subjected to the unnecessary pain and suffering associated with an operative procedure, considering their short mean survival time.

PGE1, dexamethasone, U-74389G, or Bt2-cAMP as an additive to promote protection by UW solution in I/R injury

A method to reduce ischemia-reperfusion (I/R) injury can be an important criterion to improve the preservation solution. Although University of Wisconsin solution (UW) works as a lung preservation solution, its attenuation effect on I/R injury has not been investigated. We attempted to determine whether, by adding various protective agents, modified UW solutions will enhance the I/R attenuation by UW. We examined the I/R injury in an isolated rat lung model. Various solutions, e.g., physiological salt solution (PSS), UW, and modified UW solutions containing various protective agents such as prostaglandin E1, dexamethasone, U-74389G, or dibutyryl adenosine 3',5'-cyclic monophosphate were perfused individually to evaluate the I/R injury. Isolated rat lung experiments, with ischemia for 45 min, then reperfusion for 60 min, were conducted in a closed circulating system. Hemodynamic changes, lung weight gain (LWG), capillary filtration coefficient (Kfc), protein content of lavage fluid, concentration of cytokines, and lung histopathology were analyzed. Results showed that the acute I/R lung injury with immediate permeability pulmonary edema was associated with an increase in tumor necrosis factor-alpha (TNF-alpha) production. A significant correlation existed between TNF-alpha and Kfc (r = 0.8, P < 0.0001) and TNF-alpha and LWG (r = 0. 9, P < 0.0001), indicating that TNF-alpha is an important cytokine modulating early I/R injury. Significantly lower levels of Kfc, LWG, TNF-alpha, and protein concentration of lung lavage (P < 0.05) were found in the UW-perfused group than in the control group perfused with PSS. Modified UW promoted the protective effect of UW to further decrease Kfc, LWG, and TNF-alpha (P < 0.05). Histopathological observations also substantiated this evidence. In the UW+U-74389G group, bronchial alveolar lavage fluid contained lowest protein concentration. We conclude that the UW solution attenuates I/R injury of rat lung and that the modified UW solutions further enhance the effect of UW in reducing I/R injury. Among modified solutions, UW+U-74389G is the best. Further investigation of the improved effects of the modified UW solutions would be beneficial in lung transplantation.

Subconjunctival retention of C3F8 gas increased the success rates of trabeculectomy in young people

In this study, the effect of subconjunctival retention of perfluoropropane (C3F8) gas on trabeculectomy was evaluated to determine if this maneuver would increase the success rate of the surgery. Thirty-two patients (under 35 years old) with a diagnosis of primary open-angle glaucoma or steroid-induced glaucoma were randomized into two groups to receive trabeculectomy: Group A (trabeculectomy alone, 16 eyes) and Group B (trabeculectomy with subconjunctival retention of 0.5 mL pure C3F8 gas, 16 eyes). The results showed that the typical appearance of a subconjunctivally retained C3F8 filtering bleb is highly distended in the first two weeks after surgery, followed by flattening and diffusing gradually. The average retention time of C3F8 gas within the subconjunctival space is 28 +/- 6 days. A higher success rate was noted in Group B than in Group A (94% versus 50%, p = 0.016) at a mean follow-up time of 12 months. However, there were no differences in complication rates and results of final visual acuity between the two groups (both groups had two patients lose more than two lines of vision, p = 1.0). Our study suggests that subconjunctival retention of C3F8 gas increases the success rate of trabeculectomy in young people in the intermediate-term (12 months) follow-up period.

The influence of endometriosis on the success of gamete intrafallopian transfer (GIFT)

PURPOSE

Our purpose was to evaluate the outcomes of gamete intrafallopian transfer (GIFT) therapy in patients with endometriosis.

METHODS

One hundred eight GIFT cycles performed under the indication of endometriosis were compared to 156 GIFT cycles with indications of other disease entities. A maximum of seven oocytes was transferred into one or both fimbriate ends with prepared spermatozoa. Clinical pregnancy rates and outcomes were evaluated according to Mantel-Haenszel's chi-square test. Multiple logistic regression analysis was performed to determine factors influencing the success on pregnancy in the total treatment cycles.

RESULTS

The anthropological variables, such as age of patients, duration of infertility, and semen grading, were comparable in both groups. The responses to controlled ovarian hyperstimulation (COH) were progressively decreased while increasing the severity of endometriosis conditions such as nonendometriosis, mild-form endometriosis, and advanced-form endometriosis patients. However, there were no significant differences in the clinical pregnancy rates (40.4, 36.7, and 41.7%, respectively), multiple pregnancy rates (34.9, 27.3, and 45.0%, respectively), and early pregnancy loss rates (27.0, 18.2, and 30.0%, respectively). Multivariate statistics of pregnancy rates that adjusted the effects of patients' age, tubal health, presence of active endometriosis and/or endometriomas, number of oocytes transferred, and quality of sperm exhibited no statistical significance between endometriosis and nonendometriosis groups.

CONCLUSIONS

Our data show that patients with records of endometriosis have both a decreased ovarian response to gonadotropin stimulation and a decreased number of retrieved oocytes. Since the number of oocytes needed for the GIFT procedure is limited, pregnancy results for patients in the study group were comparable with those for patients in the control group.

Residual abnormalities of pulmonary function in asymptomatic young adult asthmatics with childhood-onset asthma

We investigated the pulmonary function of male asthmatics with childhood-onset asthma. Our results revealed that adult asthmatics with mild symptoms apparently have abnormal pulmonary function. On the other hand, after a 3-6-month symptom-free period, and even after inhalation of bronchodilator, they still showed significant residual abnormalities in pulmonary function. Pulmonary function tests are very sensitive tools for the assessment of airway limitations during an acute asthmatic attack. However, these tests are not sensitive enough to detect residual abnormalities in asymptomatic asthmatics. Although the positive predictive rate for detecting small airway dysfunction in asymptomatic asthmatics is not high, FEF25-75 proved to be the best (63.2%) among the conventional pulmonary function parameters. We therefore suggest using FEF25-75 instead of FEV1 or peak flow rate in clinical practice for the conventional assessment of effectiveness of treatment, especially in the follow-up of asthmatic patients. More sensitive and simple tests are required in the future for detection of small airway dysfunction in asymptomatic asthmatics. Moreover, strict and early treatment of this abnormality with steroids is mandatory to prevent the formation of sequelae.

Pneumocephalus in a case of nasopharyngeal carcinoma

An extensive mass involving the skull base was found in a 49-year-old male patient with nasopharyngeal carcinoma. Deteriorating neurologic status developed 2 weeks after radiation to the nasopharynx with the initial dosage of 5480 cGy and boosted dosage of 3520 cGy. Computerized tomography revealed multiple foci of air occupying the subarachnoid space, and an air-fluid level was found in the lateral ventricle. Antibiotics and conservative treatments were administered to the patient and consciousness returned gradually. Unfortunately, he died of hypovolemic shock owing to massive bleeding from the nasopharynx 7 days later.

Respiratory distress and selective muscle involvement in central core disease: report of a case

A 10-year-old girl who had suffered life-threatening respiratory distress in late infancy and mild muscle weakness in the extremities was found to have central core disease (CCD). Her developmental milestones were markedly delayed and she became ambulant at the age of 6 years. On physical examination, she had a high-arched palate, nasal tone vocalization, a positive Gowers' sign, waddling gait, and decreased deep tendon reflexes. On magnetic resonance imaging (MRI) examination, the thigh, calf, arm, and paravertebral muscles were selectively involved, especially in the paravertebral, biceps brachii, gluteus maximus and medius, vastus lateralis and medialis, sartorius, adductor magnus, tibialis anterior, soleus, lateral head of gastrocnemius, and peroneus longus muscles. Two biopsy specimens from the left biceps brachii and rectus femoris muscles showed the common histochemical findings of CCD, including type 1 fiber atrophy and predominance, and core structures. Proliferation of adipose tissue was only present in the biceps brachii muscle. The patient improved clinically in muscle strength after three year follow-up. Muscle MRI may provide a non-invasive evaluation of gross muscle involvement in CCD.

Microscopic Particle Motions in Strongly Coupled Dusty Plasmas

The microscopic particle motions from the crystal to the disordered state of a dusty plasma with micrometer-sized silicon dioxide particle suspensions in a radio-frequency glow discharge system were studied through an optical microimaging system. Small-amplitude random motion around the lattice sites of the crystal state, relative domain motion with varying boundaries, cooperative hopping in the liquid state, and highly disordered motion with increasing radio-frequency power were observed. Chaotic states with different spatial scales under the coherent and stochastic coupling between dust particles and self-organized background plasma fluctuations were also demonstrated.

Nasal septal cyst--a case report

The usual complications of submucous resection of the nasal septum (SMR) are septal hematoma, infection, hemorrhage, septal perforation, and nasal deformity. We present a case of nasal septal cyst which may be a rare complication of SMR. Entrapment of free nasal mucosal remnants or inward folding of incised septal mucosa is thought to be the cause. The patient underwent deroofment of the left cystic wall by lateral rhinotomy. There was no recurrence after one year.

Mitochondrial NADH-coenzyme Q reductase deficiency in Leigh's disease

A 4 1/2-month-old girl suffered from psychomotor retardation, generalized hypotonia, poor feeding, hyperreflexia, nystagmus, optical atrophy and choreoathetosis from the age of 3 months. Her blood lactate level was elevated to 40 mg/dL. Magnetic resonance imaging of her brain showed low T1 and high T2 signal intensities in the bilateral putamen, thalamus, red nuclei, substantia nigra, superior and inferior colliculi, cerebral peduncles and periaqueductal lesions. Muscle histochemistry and electron microscopic examinations were all normal except for variation in fiber size showing a myopathic change. An assay of muscle mitochondrial respiratory enzyme activities revealed a deficiency of NADH-coenzyme Q reductase. Molecular analysis did not reveal the putative T to G transversion at the nucleotide 8,993 of mitochondrial DNA in muscle biopsies. Leigh's disease was indicated by the clinical and radiologic manifestations. The patient died at 10 months of age from pneumonia and respiratory failure. There have been only sporadic reports of patients with Leigh's disease in Taiwan, and, to our knowledge, this is the first documented case of a Taiwanese patient with mitochondrial NADH-coenzyme Q reductase deficiency.

Electrocardiographic findings in children with spinal muscular atrophy

Most of the patients in this study with spinal muscular atrophy were found to have tremors of the isoelectric line in the electrocardiogram (ECG) tracings. There were a total of 47 cases of SMA (mean age 40.8 months). All three types of SMA had a similar incidence (about 80%) of tremors in the tracings (p = 0.885). In 7 cases the ECG tremors had an intermittent pattern. ECG tremors were commonly found in the majority of SMA patients and this finding, though non-specific, may suggest a possible SMA diagnosis.

Mushroom poisoning in children: report of an accident

There were very few cases of mushroom poisoning every year in Taiwan and yet no fatal incident have been reported. A species named Amanita phalloides had high lethality rate (22-33%). Physicians should be aware of it's toxic property and be able to treat the patient in case of mushroom poisoning. However, mycologist sometimes might not distinguish edible from toxic mushroom so that educating people not to ingest wild mushroom is very important. We present 4 children with gastrointestinal syndrome after ingesting wild mushroom. We also introduce some basic approaches in treating mushroom poisoning in this paper.

Reduction in lymphocyte beta-adrenergic receptor density in infants and children with heart failure secondary to congenital heart disease

To identify changes in catecholamine levels and beta-adrenergic receptor density in children with varying degrees of congestive heart failure, we measured plasma norepinephrine (NE), epinephrine, and beta-adrenergic receptor levels in 91 noncyanotic patients using high-performance liquid chromatography and a radioligand binding assay. Plasma NE levels in 41 patients with heart failure (694 +/- 236 pg/ml) were significantly higher than those in 50 patients without it (274 +/- 68 pg/ml, p < 0.001). In addition, beta-adrenergic receptor density was significantly lower in patients with heart failure (0.81 +/- 0.48 fmol/10(6) cells) than in those without it (2.43 +/- 1.09 fmol/10(6) cells, p < 0.001), but epinephrine levels were not significantly different between the 2 groups. The receptor reduction in heart failure correlated well with elevated plasma NE levels (r = -0.60, p < 0.001). The degree of left to right shunt flow and pulmonary systolic pressure correlated directly with plasma NE levels and inversely with beta-adrenergic receptor density. From the best compromise between sensitivity and specificity, the optimal cutoff point for heart failure was > 390 ng/ml for NE and < 1.30 fmol/10(6) cells for beta-adrenergic receptor density, respectively. A follow-up study in 15 of 30 patients with heart failure after surgery showed a significant decrease in plasma NE and an increase in beta-adrenergic receptor density. Changes in plasma NE levels and beta-adrenergic receptor density occur concurrently with clinical symptoms of heart failure and may be used as indexes for assessing the presence and severity of heart failure in infants and children.

Pharmacokinetics and intraocular pressure lowering effect of timolol preparations in rabbit eyes

Two timolol preparations, a gel and an eyedrop with a thickening agent, and one commercial eyedrop without a thickening agent, were studied in rabbits. After topical administration of these three preparations in rabbits, aqueous humor was withdrawn and the proteins removed from the samples by precipitation with acetonitrile. Timolol concentrations were determined directly by an HPLC method. The HPLC mobile phase was composed of methanol and 5 mM d-camphorsulfonic acid (in 1% acetic acid) with a ratio of 49:51 (v/v). A reversed phase C18 column was used to separate samples with a flow rate of 0.8 mL/min and a UV detector set at 284 nm. A two-compartment pharmacokinetic model was used to fit the aqueous humor level for determining the drainage (kd) and absorption rate constants (ka) in the precorneal area as well as the elimination rate constant (ke) of timolol in aqueous humor. For ka +kd, the eyedrop without a thickening agent had the highest value (0.160 min-1), followed by the eyedrop with a thickening agent (0.030 min-1), and the gel had the lowest value (0.009 min-1). It suggests that the gel has a longer retention time in eyes to improve ocular bioavailability and decrease side effects. The AUC0 approximately infinity for the aqueous humor profile with time coordinates were 4142, 2974, and 1604 micrograms min/mL, for the gel, the eyedrop with a thickening agent, and the eyedrop without a thickening agent, respectively. In another study, timolol preparations were also topically administered in alpha-chymotrypsin-induced glaucoma rabbits for determining the lowering effect on intraocular pressure (IOP). The durations of depressing IOP for the gel, the eyedrop with a thickening agent, and the eyedrop without a thickening agent were 24, 14 and 10 hrs, respectively. Thus, the gel preparation has a longer duration and a higher ocular bioavailability which might be further developed in the treatment of open-angle glaucoma.

Increase of ocular blood flow by some phytogenic compounds

The effects of a number of phytogenic compounds on ocular blood flow were measured by the colored microsphere technique in rabbits. Methyltyramine and coumarin increased blood flow in all eye tissues tested. The blood flow of iris, ciliary body-iris root, retina and choroid was increased by methyltyramine for 255%, 322%, 189%, and 189%, respectively, and by coumarin for 375%, 193%, 139% and 299%, respectively, at 120 minutes after drug administration. Rescinnamine, apocynin and hesperetin also increased ocular blood flow in all eye tissues except retina. The blood flow of iris, ciliary body-iris root, and choroid was increased by rescinnamine for 344%, 234%, and 199%, respectively; by apocynin for 355%, 152%, and 414%, respectively; and by hesperetin for 265%, 136%, and 204%, respectively, at 120 minutes after drug instillation. These results indicate that these compounds could be used to treat ischemic eye diseases in the future.

Ethanol and acetaldehyde metabolism in chinese with different aldehyde dehydrogenase-2 genotypes

Alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) are the major enzymes responsible for ethanol metabolism in humans. Both enzymes exhibit genetic polymorphisms among racial populations. About half of the Chinese population lack mitochondrial ALDH2 activity and such a deficiency has been believed to be a negative risk factor for the development of alcoholism. To assess ethanol and acetaldehyde metabolism in Chinese with different ALDH2 genotypes, we genotyped 273 male adults at the ADH2, ADH3, and ALDH2 loci by using polymerase chain reaction-directed mutagenesis and restriction fragment length polymorphisms. Of the 143 individuals homozygous for both the ADH2*2 and the ADH3*1 alleles, 80, 55, and 8 were identified as ALDH2*1/*1, ALDH2*1/*2, and ALDH2*/*2, respectively. Five each from the above three ALDH2 genotypic subjects underwent alcohol elimination testing. Blood ethanol and acetaldehyde levels were determined at various times up to 130 min after intaking a low dose of ethanol (0.2 g/kg body weight) by using head-space gas chromatography and high-performance liquid chromatography with fluorescence detection, respectively. The mutant homozygotes of ALDH2*2/*2 and the heterozygotes exhibited significantly higher peak acetaldehyde concentrations and also greater areas under the blood concentrations-time curve (AUC) than did the normal homozygotes of ALDH2*1/*1, with the mutant homozygotes both being the largest. The mutant homozygotes displayed significantly higher peak ethanol levels and AUC compared to the normal homozygotes. Of the 17 subjective feeling items tested, palpitation, facial warming, effects of alcohol, and dizziness were found to be most pronounced among the mutant homozygotes.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in phrenic, hypoglossal and recurrent laryngeal nerve activities after intravenous infusions of aminophylline in cats

Aminophylline is known to have respiratory stimulant properties, and it has been suggested that it may also be effective in sleep apnoea. However, its role in this disorder remains uncertain. Theoretically, increasing upper airway motoneural activity in order to maintain airway patency might alleviate obstructive sleep apnoea. On the other hand, increasing the respiratory drive may also prove beneficial in treating central sleep apnoea. In these studies, we attempted to determine the effect of aminophylline on neural activities of the upper airway and diaphragm. We administered intravenously either a low dose (4 mg.kg-1) or a high dose (16 mg.kg-1) of aminophylline to decerebrated, vagotomized and paralysed cats, and continuously recorded the phrenic hypoglossal and recurrent laryngeal nerve activities for 3 h. Results showed that a high dose of aminophylline induced a marked increase in phrenic nerve activity, but not hypoglossal or recurrent laryngeal nerve activity. In a group treated with a low dosage of aminophylline, a significant increase of activity was found in all three nerves. Furthermore, phrenic nerve activity increased more with a high dose than with a low dose. We confirmed that aminophylline has dose-dependent and selective effects on respiratory neural activity. A low dose acts on the upper airway and diaphragm, but a high dose induces a marked increase in central respiratory drive. According to our results, low dose aminophylline might be beneficial in obstructive sleep apnoea, whereas, a high or low dose might improve some cases of central sleep apnoea.

Changes in phrenic, hypoglossal and recurrent laryngeal nerve activities after intravenous infusions of aminophylline in cats

Aminophylline is known to have respiratory stimulant properties, and it has been suggested that it may also be effective in sleep apnoea. However, its role in this disorder remains uncertain. Theoretically, increasing upper airway motoneural activity in order to maintain airway patency might alleviate obstructive sleep apnoea. On the other hand, increasing the respiratory drive may also prove beneficial in treating central sleep apnoea. In these studies, we attempted to determine the effect of aminophylline on neural activities of the upper airway and diaphragm. We administered intravenously either a low dose (4 mg.kg-1) or a high dose (16 mg.kg-1) of aminophylline to decerebrated, vagotomized and paralysed cats, and continuously recorded the phrenic hypoglossal and recurrent laryngeal nerve activities for 3 h. Results showed that a high dose of aminophylline induced a marked increase in phrenic nerve activity, but not hypoglossal or recurrent laryngeal nerve activity. In a group treated with a low dosage of aminophylline, a significant increase of activity was found in all three nerves. Furthermore, phrenic nerve activity increased more with a high dose than with a low dose. We confirmed that aminophylline has dose-dependent and selective effects on respiratory neural activity. A low dose acts on the upper airway and diaphragm, but a high dose induces a marked increase in central respiratory drive. According to our results, low dose aminophylline might be beneficial in obstructive sleep apnoea, whereas, a high or low dose might improve some cases of central sleep apnoea.

Ocular hypotensive effects of L-arginine and its derivatives and their actions on ocular blood flow

Effects of L-arginine and some related compounds on the intraocular pressure recovery (IOPR) and ocular blood flow in rabbits had been studied. It was found that L-arginine (RVC-579) and N alpha-benzoyl-L-arginine ethyl ester (RVC-578) delayed the IOPR markedly: The IOPR of the contralateral non-treated eye was delayed to the same extent as the treated eye. The effects of closely related congeners L-(+)-canavanine (RVC-581) and L-homoarginine (RVC-580) on the IOPR were qualitatively similar to RVC-579 and RVC-578 but less effective. RVC-578 was found to increase the blood flow significantly in ciliary body, retina and choroid. On the other hand, NG-nitro-L-arginine, a nitric oxide (NO) synthase inhibitor, reduced the blood flow in choroid at 60 and 120 min after drug administration and did not increase the blood flow in iris, ciliary body and retina. These results indicate that L-arginine and its derivative are capable of lowering the IOP possibly through the formation of nitric oxide to relax the blood vessel and to reduce the IOP as a result.

Effects of cromakalim and nicorandil on intraocular pressure after topical administration in rabbit eyes

In the study two potassium channel activators, cromakalim and nicorandil, were investigated in rabbits using three different levels of intraocular pressures (IOPs), including alpha-chymotrypsin-induced ocular hypertension, hypotension (IOP recovery method) and normal tension. Cromakalim significantly increased IOP during the initial period in normotensive and hypotensive rabbits, but in the later time, reduced IOP in the alpha-chymotrypsin-induced model. Nicorandil had a similar but less potent effect. In addition, cromakalim also affected ocular blood flows, which had a trend to reduce blood flow about 2-3 hr later, after topical administration of the eyedrop. Two possible mechanisms for increasing IOP effect of potassium channel activators were: (a) enhancing the formation of aqueous humor; (b) relaxing the trabecular meshwork to reduce the outflow of aqueous humor.