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.

Distribution of ganglion neurons in the trachea of the rat

The nerve plexuses and ganglionic nerve cells of rat trachea were studied quantitatively in whole-mount preparations stained for acetylcholinesterase. Two nerve plexuses were observed overlaying the smooth muscle layer of the membranous part or the rat trachea. On average, 70 ganglia (range 63-78, S.D. = 6) and 549 neurons (range 334-661, S.D. = 125) were found on the nerve plexuses. About 80% of ganglia are distributed in the thoracic part of the trachea. The ganglia are relatively small, 77% of the tracheal ganglia contain only 5 (or fewer) neurons. The profile area of neurons are about 474 microns2 (range 207 microns2-918 microns2). It appears that the uneven distribution of neurons is attributed to the increased volume of the thoracic tracheal smooth muscle. The ultrastructural features of the rat tracheal ganglia is similar to that of other species. A few regular processes of fibroblasts form the perineurium of the ganglia. Collagen fibrils, myelinated and unmyelinated nerve fibers and blood vessels are present inside the ganglia. The presence of muscular blood vessel within the tracheal ganglion has nerve been reported before. This may further support the possibility that the tracheal ganglion receives a separate blood supply.

The mucoceles or pyoceles of the paranasal sinuses

Fifty-five mucopyoceles in 53 patients were diagnosed during the 10-year period from 1982 to 1992 in our department. These included 8 from the frontal sinus, 25 from the maxillary sinus, 10 from the ethmoidal sinus, 1 from the maxillary and ethmoidal sinuses, 7 from the frontoethmoidal sinuses and 4 from the sphenoethmoidal sinuses. The patients ranged in age from 8 to 78 years (mean 47.1 years). The ratio of males to females was 31 to 22. The rhinologic symptoms occurred most often in maxillary mucopyoceles and were rare in the other groups whereas ophthalmic symptoms were noticed in most of the cases. All of the cases received surgery and postoperatively most of the initial symptoms subsided except that two patients still had occasional diplopia and one did not recover at all from complete blindness. Two cases had a recurrence and one suffered from subarachnoid hemorrhage shortly after discharge. Surgery is the only treatment modality for mucopyoceles and the building of a new patent communication between the lesion and nasal cavity is important for the success of this surgery.

Protamine-induced acute lung injury and the protective effect of agents that increase cAMP

Polycations, such as protamine sulfate and polylysine, have been implicated in acute lung injury. We studied the vascular effect of protamine sulfate and the protective effect of agents that increase cAMP in isolated rat lungs perfused with a cell- and plasma-free solution. Protamine sulfate (3 mg) markedly increased pulmonary artery pressure (PAP) from 15.6 +/- 0.5 to 30.8 +/- 1.2 mmHg (P < 0.01) and lung weight gain (LWG) by 7.8 +/- 1.5 g within 30 min (P < 0.001). The protective effects of pharmacological agents that increase intracellular cAMP were investigated. These agents included dibutyryl adenosine 3',5'-cyclic monophosphate (DBcAMP, a cAMP analogue), aminophylline and pentoxifylline (both are phosphodiesterase inhibitors). Pretreatment with these agents 5 min before protamine administration largely attenuated the increases in PAP and LWG. Because DBcAMP, aminophylline and pentoxifylline all share the effects of increasing intracellular cAMP and were effective on the protamine-induced lung changes, the intracellular level of cAMP could be a major determinant of lung injury. Since there is no blood in the perfusate, the mechanism of cAMP on cellular components in the blood such as neutrophils, can be ruled out. The endothelial cells are likely to be the target cells because charge interaction is believed to occur on the endothelial surface. This result will be very important in the elucidation of the protective effect of cAMP in acute lung injury.

Alteration of amino acid in plasma and cerebrospinal fluid of children with seizure disorders

Amino acid levels in plasma were measured by amino acid autoanalyser in 130 convulsive children. The levels of taurine, serine and tryptophan were significantly lower in convulsive children as compared to normal control; in contrast, isoleucine, homocystine, GABA, histidine, arginine and ammonia were higher. The children with paroxysmal disorders (headache, dizziness and abdominal epilepsy) had the highest levels of isoleucine, histidine and arginine and the lowest levels of glutamate and cystein. Clinical seizure activity within 6 months prior to the test seemed to have no obvious effect on the plasma amino acid pattern, except for the levels of glycine and arginine tended to return to normal, and the level of GABA was significantly increased in patients with the seizure being controlled. The patients treated with carbamazepin as a single anticonvulsant had the highest GABA level compared to those with other anticonvulsants. Hyperglycinemia and hyperammonaemia were also noted in patients who took valproic acid. The levels of serine, isoleucine and phenylalanine in the CSF within 6 hours after convulsion were significantly lower than the normal control; while asparagine, tyrosine, lysine and arginine were significantly higher. The concentration of ammonia in the CSF was also elevated after convulsion as compared to the normal control. Amino acids play an important role in the generation of epilepsy and recently there has been an increasing number of studies to help determine their effects during an epileptic attack. However, there still is much debate and controversy on this topic. Therefore, further studies are needed and researchers should carefully consider factors that might affect the accurate assessment of the results.

Duchenne muscular dystrophy: MR grading system with functional correlation

The pelvic girdle, thigh, and calf muscles of 29 patients with Duchenne muscular dystrophy (DMD) were evaluated with magnetic resonance (MR) imaging. The muscles that were most resistant to disease were the gracilis, followed by the sartorius, semitendinous, and semimembranous. Sixteen patients had asymmetric involvement in part of the muscle bundles of thigh. An MR grading system was developed to assess the number of preserved pelvic and thigh muscles, the severity of fatty infiltration of the calf, and the increase of subcutaneous fat. Statistically significant correlations were obtained between MR grade and clinical functional grade (P < .01), MR grade and disease duration (P < .01), and MR grade and patient age (P < .01). An inverse correlation was observed between the creatine kinase values and the MR grade (P < .05). The MR grading system helped identify disease severity in patients with low clinical functional grades. Twenty-four follow-up studies were performed in 22 patients. In 13 of the 24 cases, the MR grade progressed while the clinical functional grade remained unchanged. Both the MR and clinical functional grades progressed in six cases. The results suggest that MR imaging may be useful in prebiopsy mapping and may help accurately monitor the progression of DMD.

Studies of topical carbonic anhydrase inhibitors: ocular hypotensive effect of thiadiazole derivatives

A series of thiadiazole derivatives were topically applied in gels or suspensions to rabbits to determine their ocular hypotensive effect. As a result, the compounds with higher corneal permeabilities showed stronger effect in lowering IOP. In addition, gels also caused stronger effect than suspensions. Different concentrations of gel preparations produced diverse ocular hypotensive effects. A linear relationship between the integrated IOP response and logarithm concentration of inhibitor was found. It is proposed that the ocular hypotensive effect was attributed to the level of inhibitor in ciliary body.

Studies of carbonic anhydrase inhibitors: physicochemical properties and bioactivities of new thiadiazole derivatives

A series of thiadiazole derivatives of carbonic anhydrase inhibitors were prepared and their physicochemical properties and pharmacological activities such as corneal permeabilities, inhibition of carbonic anhydrase activities were evaluated. The solubilities and pKa values were determined in varied pH of phosphate buffers at 35 degrees C after equilibrium. Intrinsic solubility and pKa value were calculated from the plot of solubility versus the reciprocal of hydrogen ion concentration. The distribution coefficient was determined in the system of octanol/pH 7.65 phosphate buffer. As a result, the sigma (Hammett constant) and pi (hydrophobic substituent constant) values of substituents were found to be correlated to the logarithm of Ka and partition coefficient. Corneal permeabilities of the analogue were determined in a specially designed diffusion cell using excised rabbit cornea, which ranged from 1.32 x 10(-5) (compound II) to 3.48 x 10(-7) cm/sec (compound VI). Compound with high permeability might be expected to be absorbed well after topical administration into the eye. The methodology of pH-stat was used to determine the inhibition of the carbonic anhydrase activity of the analogue. The IC50 values of the analogue around 10(-8) M as determined were less than that of acetazolamide. The results suggest that the analogue had good pharmacological activity. Finally, an equation for quantitative structure-activity relationship was established for the analogue, which is as follows: [formula: see text]

Complete nucleotide sequence and genetic organization of papaya ringspot virus RNA

The complete nucleotide sequence of the RNA genome of papaya ringspot virus (PRSV) was determined from four overlapping cDNA clones and by direct sequencing of viral RNA. The genomic RNA is 10326 nucleotides in length, excluding the poly(A) tract, and contains one large open reading frame that starts at nucleotide positions 86 to 88 and ends at positions 10118 to 10120, encoding a polyprotein of 3344 amino acids. The highly conserved sequence AAAUAAAANANCUCAACACAACAUA at the 5' end of the RNA of PRSV and those of the other five reported potyviruses shows 80% similarity, suggesting that this region may play a common important role for potyvirus replication. Two cleavage sites of the polyprotein were determined by amino acid sequencing of the N termini of helper component (HC-Pro, amorphous inclusion) and cylindrical inclusion (CI) proteins. Other cleavage sites were predicted by analogy with the other potyviruses. The genetic organization of PRSV is similar to that of the other potyviruses except that the first protein processed from the N terminus of the polyprotein (NT protein) has an M(r) of 63K, 18K to 34K larger than those of the other potyviruses. The cleavage site for liberating the N terminus of the HC-Pro protein was found at the same location down-stream from the consensus sequence FI(V)VRG as that reported for tobacco vein mottling virus. The NT protein of potyviruses is the most variable and may be considered important for identification of individual potyviruses. The most conserved protein of potyviruses appears to be the NIb protein, the putative polymerase for the replication of the potyviral RNA. The genetic organization of PRSV RNA is tentatively proposed to be VPg-5' leader-63K NT-52K HC-Pro-46K-72K CI-6K-48K NIa-59K NIb-35K coat protein-3' non-coding region-poly(A) tract.

Role of platelets in microembolism-induced acute lung injury

The role of platelets in acute lung injury has not been well defined. In the present study of isolated perfused rat lungs, a significant increase in pulmonary arterial pressure (PAP), lung weight and the lung lavage fluid protein concentration occurred when 3 mL of a CaCl2 suspension (25 mg/mL) was mixed with blood-KHB (Krebs-Henseleit Buffer) perfusate; or when platelets were added instead of blood. However, such an increase was not observed (p > 0.05) when only KHB was used. When a comparatively small amount (0.75 mL) of the CaCl2 suspension (50 mg/mL) was added to the KHB perfusate, PAP, lung weight and the lung lavage protein concentration increased only when PAF (platelet activating factor) and platelets were both added before, but not separately. The above phenomena show that platelets are actively involved in the mechanism of acute lung injury and play an extremely important role in this microembolic model.

Dimethylthiourea ameliorates acute lung injury induced by phorbol myristate acetate in dogs

BACKGROUND AND METHODS

The protective effects of dimethylthiourea, a potent scavenger of hydroxy radical (.OH) and hydrogen peroxide, in experimental lung injury in large animals remain controversial. The present study was designed to determine whether dimethylthiourea can ameliorate the acute lung injury produced in dogs by phorbol myristate acetate. Six dogs were infused with dimethylthiourea (0.75 g/kg in saline) for 1.5 hrs, beginning 1 hr before an i.v. bolus injection of phorbol myristate acetate (17 micrograms/kg); six dogs received phorbol myristate acetate (17 micrograms/kg) alone; and six dogs were infused with saline alone. Hemodynamic changes, arterial oxygenation, and the development of lung edema were monitored for 4 hrs after phorbol myristate acetate injection to assess the extent of lung damage.

RESULTS

As compared with the dogs that received phorbol myristate acetate alone, the edematous lung damage was significantly reduced in those dogs that received dimethylthiourea as well as phorbol myristate acetate. In the dimethylthiourea-treated dogs, the lung wet/dry weight ratios were smaller (p less than .01); protein concentrations in lung lavage fluid were lower (p less than .01); the decrease in PaO2 was significantly reduced (p less than .01); and there were significant reductions in the alveolar-arterial oxygen tension difference (P[A-a]O2) (p less than .01) and shunt (Qsp/Qt) (p less than .05). Also, dimethylthiourea significantly lowered the increased mean pulmonary arterial pressure levels during the second half of the experiment.

CONCLUSIONS

These experimental data suggest that dimethylthiourea is capable of reducing the neutrophil-mediated lung injury produced by the release of hydroxy radical and/or hydrogen peroxide in dogs exposed to phorbol myristate acetate.

Stability studies of topical carbonic anhydrase inhibitor 6-hydroxyethoxy-2-benzothiazole sulfonamide

A new carbonic anhydrase inhibitor, 6-hydroxyethoxy-2-benzothiazole sulfonamide (6-hydroxyethyoxyzolamide), was studied to determine its stability in aqueous solution from pH 2.9 to 9.2 at a constant ionic strength of 0.15 M. This newly synthesized derivative of ethoxyzolamide has demonstrated clinical efficacy for use as an ophthalmic drug to lower intraocular pressure. Drug solution in sealed ampules was placed in a constant temperature over either at two temperatures (75 and 85 +/- 0.2 degrees C) or four temperatures (75, 80, 85, and 90 +/- 0.2 degrees C). Samples were analyzed by known HPLC methods. The results indicated that 6-hydroxyethoxyzolamide is most stable at pH 4 to 5.5. The aqueous drug solutions at pH 7.0 and 8.0 were, nevertheless, sufficiently stable, based on extrapolation of kinetic data at high temperatures using the experimentally determined Arrhenius equation. The degradation compound was identified by spectral analysis to have a hydroxyl group substituting for the original -SO2NH2 group.

Recombinant pseudorabies virus carrying a plasmodium gene: herpesvirus as a new live viral vector for inducing T- and B-cell immunity

In Balb/c mice, the sterile protective immunity induced by immunization with radiation-attenuated Plasmodium yoelii sporozoites is eliminated by in vivo depletion of CD8+ T lymphocytes, suggesting that cytotoxic T lymphocytes (CTL) against malaria antigens expressed on infected hepatocytes are required for mediating this protective immunity. To produce a vaccine that would induce CTL against the P. yoelii circumsporozoite protein (CS), we constructed an attenuated pseudorabies virus (PRV) containing a gene encoding this protein. Balb/c mice that received three doses of 10(7) plaque-forming units (p.f.u.) of this vaccine intravenously at 3 week intervals developed high levels of antibodies to sporozoites (indirect fluorescent antibody titre = 4096) and CTL against a 16 amino acid epitope (SYVPSAEQILEFVKQI, amino acids 281-296) from the P. yoelii CS protein designated PYCTL1. The cytotoxic activity of the CTL was antigen-specific, MHC-restricted, and dependent on CD8+ T cells. Furthermore, these CTL eliminated P. yoelii-infected hepatocytes from in vitro culture, indicating that they recognize this peptide on the surface of infected hepatocytes. However, all nine mice that were challenged with 200 sporozoites developed a blood-stage malaria infection. We attribute this lack of protection to the great difficulty of inducing sterile immunity against this highly infectious parasite P. yoelii. We conclude that recombinant pseudorabies virus (PRV) worked successfully as a live vaccine vector to induce both antibodies and CTL, albeit non-protective in vivo, and the herpesviruses should be considered as subunit vaccines where T- and B-cell immunity is required.