[Development and clinical application of the full automatic animal rearing cabin of low oxygen and high carbon dioxide]

This paper introduces a kind of automatic animal rearing cabin of low oxygen and high carbon dioxide. It can mimic the environment of low oxygen and high carbon dioxide at atmospheric pressure and automatically measure and control the concentrations of oxygen and carbon dioxide as well as temperature and humidity in the cabin. The system may provide the equipment support for clinical COPD study. The clinical applications show that the cabin with accurate measurement and control is practical and reliable.

Effect of ipratropium bromide on airway and pulmonary muscarinic receptors in a rat model of chronic obstructive pulmonary disease

OBJECTIVE

To observe the level of muscarinic receptors in airway and lung tissues, and the effect of inhaled ipratropium bromide on these receptors in a rat model of chronic obstructive pulmonary disease (COPD).

METHODS

This model was developed by exposure of rats to 250 ppm SO2 gas, 5 h/d, 5 d/wk, for a period of 7 wk. The COPD rats inhaled 0.025% aerosolized iratropium bromide for 20 min, 2 times daily, in an airtight chamber. Muscarinic receptors in airway and lung tissues of normal rats, ipratropium bromide-treated COPD rats and the recovering COPD rats were measured by the radio-ligand binding assay.

RESULTS

Airway/lung pathology and pulmonary function tests showed that chronic SO2 exposure caused pathophysiologic changes similar to those observed in human COPD. The density (0.038 +/- 0.011, pmol/mg protein) and affinity (Kd, 23 +/- 11 pmol/L) of muscarinic receptors in airway and lung tissues of COPD rats were not changed compared with those of normal control rats (0.030 +/- 0.008 and 29 +/- 19, respectively, P > 0.05). Densities of the muscarinic receptors were not changed after inhalation of ipratropium bromide for 5 days, but increased significantly after inhalation for 30 days, as compared with those of the untreated COPD rats. The muscarinic receptors returned the normal levels at day 6 after cessation of ipratropium bromide treatment. There were no differences among different groups of rats in equilibrium dissociation constants (Kd).

CONCLUSION

A rat model of COPD with pathophysiologic changes similar to the human counterpart was developed using chronic SO2 exposure. There was no significant change in the number and function of muscarinic receptors in airway and lung tissues of the COPD rats, but upregulation of the muscarinic receptors was observed after long-term inhalation of ipratropium bromide.

Erect bipedal stance exercise partially prevents orchidectomy-induced bone loss in the lumbar vertebrae of rats

This study investigates the responses of the fourth and fifth lumbar vertebral bodies of 6-month-old male Sprague-Dawley (SD) rats to orchidectomy (orx) and to erect bipedal stance for feeding for 12 weeks in specially designed raised cages (RC) for which the heights were raised from 20 cm to 35.5 cm. A total of 30 rats were divided into groups of: baseline; sham + housed in normal height cage (NC); orx + NC; sham + RC; and orx + RC. Bone histomorphometry was performed on the triple-labeled undecalcified fourth sagittal (LVL-4) and fifth transverse (LVX-5) sections. We found that orchidectomy induced high-turnover trabecular and cortical bone loss in the lumbar vertebrae. Forcing the rats to rise to erect stance for feeding reduced trabecular and cortical bone loss caused by orx. Apparently, depressing the elevated bone resorption next to the marrow induced by orx, and stimulating bone formation at the ventral periosteal surfaces, caused these effects. Orchidectomy and raised cage had similar effects on the two vertebrae except that the percentage of trabecular bone loss was greater in the LVL-4 than in LVX-5, and that bipedal stance exercise increased the total tissue area and mineral apposition rates (0-80 day interval) of ventral periosteal and dorsal endocortical surfaces of LVX-5 to a greater extent than it did in LVL-4. Such findings suggest that forcing rats to rise to an erect bipedal stance for feeding helps prevent loss of trabecular and cortical bone "mass," and presumably bone strength, in orchidectomized rats. This method also provides an inexpensive, noninvasive, reliable model to increase in vivo vertebral loading in rats that is similar in humans.

Measurement of J/psi and psi(2S) polarization in pp collisions at sqrt[s] = 1.8 TeV

We have measured the polarization of J/psi and psi(2S) mesons produced in pp collisions at sqrt[s] = 1.8 TeV, using data collected at the Collider Detector at Fermilab during 1992-1995. The polarization of promptly produced J/psi [psi(2S)] mesons is isolated from those produced in B-hadron decay, and measured over the kinematic range 4 [5.5]<P(T)<20 GeV/c and |y|<0.6. For P(T) greater than or approximately equal 12 GeV/c we do not observe significant polarization in the prompt component.

Signal transduction by GABA(B) receptor heterodimers

GABA(B) receptors are G-protein-coupled receptors that mediate inhibition throughout the central and peripheral nervous systems. A single cloned receptor, GABA(B)R1, which has at least three alternatively spliced forms, appears to account for the vast majority of binding sites in the brain for high-affinity antagonists. In heterologous expression systems GABA(B)R1 is poorly expressed on the plasma membrane and largely fails to couple to ion channels. A second gene, GABA(B)R2, which exhibits moderately low homology to GABA(B)R1, permits surface expression of GABA(B)R1 and the appearance of baclofen-sensitive K(+) and Ca(+1) currents. We review the data that supports a model of the native GABA(B) receptor as a heterodimer composed of GABA(B)R1 and GABA(B)R2 proteins. New data from mutagenesis experiments are presented that point to amino acid residues on GABA(B)R1 critical for ligand activation of the heterodimer. The possible role of GABA(B)R2 in signal transduction is also discussed. The interdependent nature of the two subunits for receptor function makes the GABA(B) receptor a useful model to explore the larger significance of GPCR dimerization for G-protein activation.

Inactivation of germline mutant APC alleles by attenuated somatic mutations: a molecular genetic mechanism for attenuated familial adenomatous polyposis

Germline mutations of the adenomatous polyposis coli (APC) tumor-suppressor gene result in familial adenomatous polyposis (FAP). Patients with FAP typically develop hundreds to thousands of benign colorectal tumors and early-onset colorectal cancer. A subset of germline APC mutations results in an attenuated FAP (AFAP) phenotype, in which patients develop fewer tumors and develop them at an older age. Although a genotype-phenotype correlation between the locations of APC germline mutations and the development of AFAP has been well documented, the mechanism for AFAP has not been well defined. We investigated the mechanism for AFAP in patients carrying a mutant APC allele (APC(AS9)) that has a mutation in the alternatively spliced region of exon 9. APC(AS9) was found to down-regulate beta-catenin-regulated transcription, the major tumor-suppressor function of APC, as did the wild-type APC. Mutation analysis showed that both APC(AS9) and the wild-type APC alleles were somatically mutated in most colorectal tumors from these patients. Functional analysis showed that 4666insA, a common somatic mutation in APC(AS9) in these tumors, did not inactivate the wild-type APC. Our results indicate that carriers of APC(AS9) develop fewer colorectal tumors than do typical patients with FAP because somatic inactivation of both APC alleles is necessary for colorectal tumorigenesis. However, these patients develop colorectal tumors more frequently than does the general population because APC(AS9) is inactivated by mutations that do not inactivate the wild-type APC.

Voltage- and use-dependent effect of 7-chlor-benzyltetrahydropalmatine on sodium currents in guinea pig ventricular myocytes

The whole-cell patch-clamp technique was employed to obtain information about the voltage-dependence and kinetics of interaction of 7-chlor-benzyltetrahydropalmatine (7-Cl-BTHP) with cardiac sodium channels. 7-Cl-BTHP (30 mol/L) significantly decreased the peak sodium current (from 7.8 +/- 1.8 nA to 5.3 +/- 1.4 nA, P < 0.01, n = 5), without producing a shift of the current-voltage curve. It shifted the inactivation curves of sodium current to hyperpolarized potentials, and the V0.5 was shifted from -(82.5 +/- 2.5) mV to -(95 +/- 2.4) mV (P < 0.05, n = 4). 7-Cl-BTHP produced a significant use-dependent effect that was proportional to the duration of the voltage step. In addition, 7-Cl-BTHP slowed the recovery of sodium channel from inactivation, which could explain its use-dependent effects on sodium current. The characteristics of 7-Cl-BTHP blockage suggest that this agent binds preferentially to inactivated sodium channels.

Search for scalar top and scalar bottom quarks in pp collisions at square root s=1.8 TeV

We have searched for direct pair production of scalar top and scalar bottom quarks in 88 pb-1 of pp collisions at sqrt[s]=1.8 TeV with the CDF detector. We looked for events with a pair of heavy flavor jets and missing energy, consistent with scalar top (bottom) quark decays to a charm (bottom) quark and a neutralino. The numbers of events that pass our selections show no significant deviation from standard model expectations. We compare our results to the next-to-leading order scalar quark production cross sections to exclude regions in scalar quark-neutralino mass parameter space.

Search for a W' boson via the decay mode W'-->munumu in 1.8 TeV pp collisions

We report the results of a search for a W' boson produced in pp collisions at a center-of-mass energy of 1.8 TeV using a 107 pb-1 data sample recorded by the Collider Detector at Fermilab. We consider the decay channel W'-->&munumu and search for anomalous production of high transverse mass munumu lepton pairs. We observe no excess of events above background and set limits on the rate of W' boson production and decay relative to standard model W boson production and decay using a fit of the transverse mass distribution observed. If we assume standard model strength couplings of the W' boson to quark and lepton pairs, we exclude a W' boson with invariant mass less than 660 GeV/c2 at 95% confidence level.

Prof. Sheng Canruo's experience in acupuncture treatment of throat diseases with yan si xue

Yan Si Xue ([symbol: see text]) refer to four points in the throat summarized by Prof. Sheng Canruo in his long-year clinical experience based on the combination of TCM theory and the knowledge of modern medical anatomy. By taking "Yan Si Xue" as main points, and other differential adjunct points, Prof. Sheng has obtained satisfactory therapeutic results in treating various throat diseases such as hoarseness, paralysis of vocal cord, dysphonia after radiotherapy on throat tumor, vocal nodules, disorder of the glossopharyngeal nerve, hysteric aphasia, and acute or chronic laryngopharyngitis.

Making rats rise to erect bipedal stance for feeding partially prevented orchidectomy-induced bone loss and added bone to intact rats

The objectives of this study were to investigate the different effects on muscle mass and cancellous (proximal tibial metaphysis [PTM]) and cortical (tibial shaft [TX]) bone mass of sham-operated and orchidectomized (ORX) male rats by making rats rise to erect bipedal stance for feeding. Specially designed raised cages (RC) were used so that the rats had to rise to erect bipedal stance to eat and drink for 12 weeks. Dual-energy X-ray absorptiometry (DEXA) and peripheral quantitative computerized tomography (pQCT) were used to estimate the lean leg mass and bone mineral. Static and dynamic histomorphometry were performed on the triple-labeled undecalcified sections. We found that making the intact rats rise to erect bipedal stance for feeding increased muscle mass, cortical bone volume, and periosteal bone formation. Orchidectomy increased net losses of bone next to the marrow by increasing bone turnover. Making the ORX rats rise to erect bipedal stance increased muscle mass, partially prevented cancellous bone loss in the PTM, and prevented net cortical bone loss in TX induced by ORX by depressing cancellous and endocortical high bone turnover and stimulating periosteal bone formation. The bone-anabolic effects were achieved mainly in the first 4 weeks in the PTM and by 8 weeks in the TX. These findings suggested that making the rats rise to erect bipedal stance for feeding helped to increase muscle mass and cortical bone mass in the tibias of intact rats, increase muscle mass, and partially prevented cancellous and net cortical bone loss in ORX rats.

Novel ligands lacking a positive charge for the delta- and mu-opioid receptors

Recently we reported using minilibraries to replace Lys(9) [somatostatin (SRIF) numbering] of the potent somatostatin agonist L-363,301 (c[-Pro-Phe-D-Trp-Lys-Thr-Phe-]) to generate the potent neurokinin receptor (NK-1) antagonist c[-Pro-Phe-D-Trp-p-F-Phe-Thr-Phe-]. This novel cyclic hexapeptide did not bind the SRIF receptor. Thus, a single mutation converted L-363,301, a SRIF agonist with potency ca. 2-8 times the potency of SRIF in laboratory animals,(24) into a selective NK-1 receptor antagonist with an IC(50) of 2 nM in vitro. During the screening of the same libraries for ligands of the delta-opioid receptor, we identified four compounds (1-4) which represent a new class of delta-opioid antagonists, some of which were also NK-1 receptor antagonists. The most potent delta-opioid antagonist, c[-Pro-1-Nal-D-Trp-Tyr-Thr-Phe-] (2), showed a K(e) value of 128 nM in the mouse vas deferens assay and a delta-receptor binding affinity constant of 152 nM in the rat brain membrane binding assay. These results are of interest because they represent a novel class of delta-opioid antagonists and, like two previously reported delta-opioid antagonists, they lack a positive charge. To examine further the requirement for a positive charge in the delta-opioid ligands, we prepared two analogues of the beta-casomorphin-derived mixed mu-agonist/delta-antagonist, H-Dmt-c[-D-Orn-2-Nal-D-Pro-Gly-] (7), in which we eliminated the positive charge either through formylation of the primary amino group (5) or by the deletion of this N-terminal amino group (6). These latter compounds proved to be delta-opioid antagonists with K(e) values in the 16-120 nM range, as well as fairly potent mu-opioid antagonists (K(e) approximately 200 nM). These six compounds provide the most convincing evidence to date that there is no requirement for a positive charge in mu- and delta-opioid receptor antagonists. In addition, cyclic hexapeptide 4 lacks a phenolic hydroxyl group. Taken together, these data suggest that the prevailing assumptions about delta- and mu-opioid receptor binding need revision and that the receptors for these opioid ligands have much in common with the NK-1 and somatostatin receptors.

Double-spin-flip resonance of rhodium nuclei at positive and negative spin temperatures

Sensitive SQUID-NMR measurements were used to study the mutual interactions in the highly polarized nuclear-spin system of rhodium metal. The dipolar coupling gives rise to a weak double-spin-flip resonance. The observed frequency shifts allow deducing separately the dipolarlike contribution and the isotropic exchange term. For the first time, such measurements were extended to negative absolute temperatures as well. We find an effective dipolar moment 0. 10&mgr;(N) of which about 15% is attributed to a conduction electron mediated pseudodipolar interaction. The isotropic exchange is described by R = -0.9+/-0.1.

Motor-unit synchronization increases EMG amplitude and decreases force steadiness of simulated contractions

The purpose of the study was to determine the effect of motor-unit synchronization on the surface electromyogram (EMG) and isometric force using a computer model of muscle contraction. The EMG and force were simulated by generating muscle fiber action potentials, defining motor-unit mechanical characteristics and territories, estimating motor-unit action potentials, specifying motor-unit discharge times, and imposing various levels of motor-unit synchronization. The output (EMG and force) was simulated at 11 levels of excitation, ranging from 5 to 100% of maximum. To synchronize motor-unit activity, selected motor-unit discharge times were adjusted; however, the number of motor units recruited and the average discharge rate of each unit was constant across synchronization conditions for a given level of excitation. Two levels of synchronization were imposed on the discharge times: a moderate and a high level, which approximated the experimentally observed range of motor-unit synchronization. The moderate level of synchrony caused the average EMG to increase by approximately 65%, whereas the high level caused a 130% increase in the EMG with respect to the no-synchrony condition. Neither synchrony condition influenced the magnitude of the average force. However, motor-unit synchronization did increase the amplitude of the fluctuations in the simulated force, especially at intermediate levels of excitation. In conclusion, motor-unit synchronization increased the amplitude of the average rectified EMG and decreased the steadiness of the force exerted by the muscle in simulated contractions.

Anabolic effect of prostaglandin E2 on cortical bone of aged male rats comes mainly from modeling-dependent bone gain

In this study, prostaglandin E2 (3 mg/kg per day) was administered to 20-month-old male Wistar rats for 10 and 30 days. Histomorphometric analyses were performed on double-fluorescent-labeled undecalcified tibial shaft sections. Thirty days of prostaglandin E2 (PGE2) administration increased bone formation rate/total bone surface from undetectable levels to 0.6 microm/day at the periosteal surface and from 0.5 to 2.1 microm/day at the endocortical surface. Endocortical osteoid surface area increased from 2% to 67% at day 10 and decreased to 6% at day 30; woven and lamellar bone formation started at day 0, but was most obvious at day 30, resulting in a 12% increase of total bone mass. The red to yellow marrow ratio was 0.2 in pretreatment controls, and increased to 1.6 by day 10 and 2.4 by day 30 with PGE2 administration. Intracortical cavity number and area increased after 10 days of PGE2 treatment, but with forming osteon number and area far exceeding those of resorption cavities at day 30. Endocortical modeling surface/endocortical surface was only 1.5%, and remodeling was 11.1% in pretreatment controls. PGE2 treatment increased modeling to 24.5% in the 10 day group and 93.7% in the 30 day group, whereas remodeling remained unchanged at 10 days, and decreased to 6.2% at 30 days. Osteoprogenitor cells and osteoblasts could not be detected in pretreatment controls, but increased by day 10, and returned almost to control levels by 30 days. Our data indicate that PGE2 induced periosteal and endocortical bone formation mainly by modeling-dependent bone gain, accompanied by increases in intracortical remodeling and red bone marrow, and a transient increase in the osteoprogenitor cells adjacent to the endocortical surface. These findings suggest that 20-month-old male Wistar rats were very responsive to the anabolic action of PGE2 in the tibial shaft, a site consisting mainly of cortical bone and yellow marrow.

Cloning and first functional characterization of a plant cyclic nucleotide-gated cation channel

Cyclic nucleotide-gated (cng) non-selective cation channels have been cloned from a number of animal systems. These channels are characterized by direct gating upon cAMP or cGMP binding to the intracellular portion of the channel protein, which leads to an increase in channel conductance. Animal cng channels are involved in signal transduction systems; they translate stimulus-induced changes in cytosolic cyclic nucleotide into altered cell membrane potential and/or cation flux as part of a signal cascade pathway. Putative plant homologs of animal cng channels have been identified. However, functional characterization (i.e. demonstration of cyclic-nucleotide-dependent ion currents) of a plant cng channel has not yet been accomplished. We report the cloning and first functional characterization of a plant member of this family of ion channels. The Arabidopsis cDNA AtCNGC2 encodes a polypeptide with deduced homology to the alpha-subunit of animal channels, and facilitates cyclic nucleotide-dependent cation currents upon expression in a number of heterologous systems. AtCNGC2 expression in a yeast mutant lacking a low-affinity K(+) uptake system complements growth inhibition only when lipophilic cyclic nucleotides are present in the culture medium. Voltage clamp analysis indicates that Xenopus laevis oocytes injected with AtCNGC2 cRNA demonstrate cyclic-nucleotide-dependent, inward-rectifying K(+) currents. Human embryonic kidney cells (HEK293) transfected with AtCNGC2 cDNA demonstrate increased permeability to Ca(2+) only in the presence of lipophilic cyclic nucleotides. The evidence presented here supports the functional classification of AtCNGC2 as a cyclic-nucleotide-gated cation channel, and presents the first direct evidence (to our knowledge) identifying a plant member of this ion channel family.

[Studies on male reproductive toxicity caused by hexavalent chromium]

OBJECTIVE

To study male reproductive toxicity caused by hexavalent chromium (Cr(VI +)).

METHODS

Morphology of semen and spermatozoa was observed and chromium level in blood, chromium and zinc level in sperm plasma, leuteinizing hormone (LH) and follicle stimulating hormone (FSH) levels in serum were determined for male workers exposed to (Cr(VI +)) (CrO(3)X = 0.0195 mg/m(3)) with occupational epidemiologic investigation and laboratory analysis.

RESULTS

For the exposed workers, their seminal counting was (52.21 +/- 45.51) x 10(9)/L, and zinc level in seminal plasma (4,811.85 +/- 1,401.88) micromol/L, significantly lower than those in controls (88.96 +/- 74.82) x 10(9)/L and (5 718.49 +/- 2 827.90) micromol/L, respectively, P < 0.05. Serum FSH was (7.34 +/- 6.88) IU/L in the exposed groups, significantly higher than that of controls (2.41 +/- 1.69) IU/L, P < 0.01. There were no significant difference in semen volume, semen liquefaction time, prevalence of teratospermia, serum Cr(VI +) and LH level in seminal plasma between exposed group and control group (P > 0.05). Prevalence of teratospermia was 0.24 +/- 0.09, and serum LH and FSH were (7.94 +/- 2.67) IU/L and FSH (9.33 +/- 6.47) IU/L, respectively, in workers exposed to high concentration of Cr(VI +) (CrO(3)X = 0.2351 mg/m(3)) significantly higher than those exposed to lower concentration of Cr(VI +) (CrO(3)X = 0.0172 mg/m(3)), with 0.17 +/- 0.06 of prevalence of teratospermia, (5.05 +/- 3.05) IU/L of LH, and (3.74 +/- 3.04) IU/L of FSH, respectively (P < 0.05).

CONCLUSION

The results suggested that damage to convoluted seminiferous tubules epithelium, reduction of spermatozoa formation and increase in prevalence of teratospermia could be caused by exposure to certain concentration of Cr(VI +).

[Effects of Rg1 on calcium channel of guinea pig ventricular myocytes]

OBJECTIVE

To evaluate the effect of Rg1 (purified saponin of Panax notoginseng) on L-Ca2+ channel of guinea pig ventricular myocytes.

METHOD

The whole-cell patch clamp recording technique.

RESULT

When the holding potential was kept at -40 mV, and the cell was depolarized to +40 mV for 150 ms at a frequency of 0.5 Hz.Rg1 10 mumol.L-1 and 30 mumol.L-1 could not reduce Bay K 8644 and nifedipine-sensitive L-type Ca2+ inward current (P > 0.05, n = 5).

CONCLUSION

Rg1 should not be a Ca2+ channel antagonist.

[Arterial infusion chemotherapy combined with concurrent radiotherapy for local advanced pancreatic cancer]

OBJECTIVE

To analyze the treatment results of un-resectable local pancreatic cancer by arterial infusion chemotherapy plus concurrent radiotherapy or radiotherapy alone.

METHODS

A total of 50 patients with local advanced pancreatic cancer from January 1992 through October 1995 were treated either by arterial infusion chemotherapy (C) plus concurrent radiotherapy (R) (22 cases) or by radiotherapy alone (28 cases). Radiation given was the same in the two groups of patients (50-60 Gy in 5 to 6 weeks, 1.8-2 Gy/Fx, 5 Fx/wk). Infusion chemotherapy was performed once every 4 weeks, consisting of 5-fluorouracil 1.0 g, mitomycin C 10 mg, cisplatin 60 mg. An average of 2.3 cycles was given to each patient.

RESULTS

Although the remission rate of jaundice and pain did not show significant difference between the two groups, patients in C + R treatment group had longer period of symptomatic remission (P < 0.05). The response rate (CR + PR) was 68.2% in C + R treatment group and 35.7% in R treatment group, respectively. The 1-, 2-, and 3-year survival rate was 75.3%, 36.8%, 25.4% in C + R treatment group, and 51.3%, 22.6%, 8.7% in R treatment group, respectively.

CONCLUSION

Arterial infusion chemotherapy combined with concurrent radiotherapy is a treatment of choice for patients with local unresectable cancer of the pancreas.

[Molecular cloning of rat OB gene and its expression in Escherichia coli]

In order to provide rat OB gene product for studying the relationship between obesity and noninfectious diseases, rat OB cDNA was amplified by RT-PCR technique. 460 bp fragment of OB cDNA was subcloned into EcoRI/BamHI site of plasmid pUC 19. Sequence analysis of OB cDNA revealed that the translation reading frame was identical with that reported in the literature. Thereby plasmid pBV220-rOB was constructed and the specific expression of OB gene in E. coli identified by SDS-PAGE electrophoresis was obtained.

Late course accelerated fractionation in radiotherapy of esophageal carcinoma

PURPOSE

To evaluate the efficacy of adding accelerated fractionation after completing two thirds of routine fractionated radiotherapy in esophageal carcinoma.

METHODS AND MATERIALS

From April 1988 to April 1990, 85 patients with histologically confirmed carcinoma of the esophagus were randomized into two groups. (1) The conventional fractionation (CF) group, received 1.8 Gy per day five times a week to a total dose of 68.4 Gy in 7-8 weeks, and (2) the late course accelerated hyperfractionated (LCAF) group which received the same schedule as the CF group during the first two thirds of the course of radiotherapy to a dose of 41.4 Gy/23 fx/4 to 5 weeks. This was then followed by accelerated hyperfractionation using reduced fields. In the LCAF portion of the radiotherapeutic course, the irradiation schedule was changed to 1.5 Gy twice a day, with an interval of 4 h between fractions, to a dose of 27 Gy/18 fx. Thus the total dose was also 68.4 Gy, the same as the CF group, but the course of radiotherapy was shorter, being only 6.4 weeks. The same Cobalt 60 teletherapy unit was used to treat all the cases.

RESULTS

The 5 year actuarial survival and disease-free survival rates in the LCAF group were 34% and 42%, as compared to 15% and 15% respectively in the CF group, all statistically significant. Better local control was seen in the LCAF group than in the CF group, the 5 year control rates being 55% versus 21% (P = 0.003). The acute reactions were increased but acceptable in the LCAF patients, the radiation treatments could be completed without any breaks. The late reactions as observed after 5 years were not increased in comparison with the CF patients.

CONCLUSIONS

The results from this study show that the late course accelerated hyperfractionated radiotherapy regime can improve results in esophageal carcinoma, with acceptable acute reactions as compared to conventional radiotherapy.

Immunolocalization of alpha4 and alpha7 subunits of nicotinic receptor in rat cochlear nucleus

The rat cochlear nucleus (CN) is known to receive cholinergic input. To investigate the prevalence of nicotinic acetylcholine receptor (nAChR), immunohistochemistry for alpha4 and alpha7 subunits, which represent nAChRs with high binding affinities for nicotine and alpha-bungarotoxin, respectively, was performed on perfusion-fixed rat brain sections. Microscopic observations and densitometric measurements show dense labeling for alpha7 but not alpha4. Within the CN, alpha7 receptors are found in all subregions, with relatively high densities in granular regions. The distribution of alpha7 within the CN appears to correlate more closely with that of acetylcholinesterase than with mAChR or choline acetyltransferase. Our results suggest a role of nicotinic cholinergic transmission in the rat CN associated with high affinity for alpha-bungarotoxin.

[The effect of inhaled ipratropium bromide on airway and lung tissue muscarinic receptors in a rat model of COPD]

OBJECTIVE

To observe the effect of inhaled ipratropium bromide on airway and lung tissue muscarinic receptors (MR) in a rat model of chronic obstructive pulmonary disease (COPD).

METHODS

The rat model of COPD was established by chronic exposure with high concentrations of SO(2) gas, COPD rats inhaled aerosolized 0.025% ipratropium bromide solution 10 ml (twice/d, 20min/time). The MR was determined by radioligand binding studies with (3)H-QNB as the ligand.

RESULTS

Compared with that of control, there was a marked increase in MR density on day 30 of treatment with ipratropium but not on day 5. The MR density decreased and close to normal level on the 6th day after cessation of regular therapy with inhaled ipratropium for 30 days. No significant difference was observed in antagonist affinity (Kd) among different time groups of ipratropium therapy.

CONCLUSIONS

Chronic exposure to the anticholinergic agent ipratropium bromide produces an up-regulation of airway MR. The airway MR density can recover to normal when treatment stopped. Up-regulation of airway MR is associated with transient bronchoconstriction following cessation of regular ipratropium therapy and lung function deteriorated following long-term inhaled ipratropium bromide.

[The effects of inhaled bronchodilators on central inspiratory drive in patients with COPD]

OBJECTIVE

To evaluate the effects of inhaled bronchodilators on the central inspiratory drive in patients with COPD.

METHODS

91 patients with COPD were divided into three groups (A, B, C) randomly. Lung functions and P(0.1) were measured at baseline and 20 min and 60 min after inhalation (A: albuterol; B: iprotropium; C: albuterol + iprotropium).

RESULTS

P(0.1) decreased after inhalation in all three groups (P < 0.05 approximately 0.001). A positive correlation between DeltaP(0.1) and DeltaFRC was found in the three groups (r = 0.4325 - 0.5230, P < 0.05 approximately 0.01). V(E)/P(0.1) increased in the three groups after inhalation (P < 0.05 approximately 0.005). There was significant improvement of V(E)/P(0.1) in group B and C as compared with that of group A (P < 0.05, P < 0.001); There was a different correlative factor with V(E)/P(0.1) in group B and C.

CONCLUSIONS

(1) P(0.1) decreased after inhalation, It may be caused by decreased FRC. (2) V(E)/P(0.1) became appropriate after inhalation in all groups; The improvement in group B and C was superior to that of group A. There may be different mechanisms to improve V(E)/P(0.1) by different inhalators.

Vesicular acetylcholine transporter in the rat cochlear nucleus: an immunohistochemical study

After being synthesized in the cytoplasm of axon terminals, acetylcholine is packaged into synaptic vesicles by a proton-dependent transporter, vesicular acetylcholine transporter (VAChT). Localization of VAChT is restricted to cholinergic neurons, especially their terminals. We used an anti-VAChT antibody from INCSTAR to localize cholinergic terminals in the rat cochlear nucleus (CN), an important brainstem auditory center. VAChT immunoreactivity in the rat CN appears as labeled puncta and a few connecting fibers. In ventral CN (VCN), VAChT-labeled puncta are closely associated with somatic profiles of medium to large neurons. In and near the granular regions of VCN, VAChT-labeled puncta are more diffusely scattered. In the subpeduncular corner and the medial sheet, some VAChT-labeled fibers are seen in connection with especially prominent VAChT-labeled puncta. In dorsal CN (DCN), VAChT-labeled puncta show no clear association with somata and are found in all layers. Ultrastructurally, VAChT labeling is seen in the cytoplasm and is associated with synaptic vesicle membrane of terminals with small round vesicles. Such VAChT-labeled terminals synapse with cell bodies and dendrites in the CN.(J Histochem Cytochem 47:83-90, 1998)

[Effects of inhalated isosorbide dinitrate on endothelin and nitric oxide and its therapeutic efficacy for experimental guinea-pigs with asthma]

To probe into the correlation between the changes of endothelin and nitric oxide in bronchial alveolar lavage fluid (BALF) and the treatment of inhaling isosorbide dinitrate on experimental guinea pigs with asthma, we divided 25 guinea pigs randomly into three groups (Control group, Asthma group, Isosorbide dinitrate group), and induced some subjects by inhalation of aerosolized ovalbumin as the model of asthma to investigate the endothelin (ET) and nitric oxide (NO) level in BALF as well as the pathological change of the respiratory tract. We found that the level of endothelin and nitric oxide in BALF were all elevated in experimental guinea pigs with asthma, but the degree of increase of NO in BALF was lower than that of ET. The NO and the ET levels in BALF were negative correlation (r = -0.8050, P < 0.01). After having been treated with aerosolized isosorbide dinitrate, the NO level in BALF was significantly elevated and the ET level in BALF was decreased in comparison with the asthma group (P < 0.001, respectively). Moreover, the eosinophile infiltration, exoserosis, and epithalaxia of the respiratory tract of the guinea-pigs were all lightened. The results suggest that inhaled isosoratory dinitrate could be used for treating asthma, and its mechanism may be elevation of NO level and decrease of ET level in BALF.

Transport characteristics of peptidomimetics. Effect of the pyrrolinone bioisostere on transport across Caco-2 cell monolayers

PURPOSE

To compare the permeation characteristics of amide bond-containing HIV-1 protease inhibitors and their pyrrolinone-containing counterparts across Caco-2 cell monolayers, a model of the intestinal mucosa.

METHODS

Transepithelial transport and cellular uptake of three pairs of amide bond-containing and pyrrolinone-based peptidomimetics were assessed in the presence and absence of cyclosporin A using the Caco-2 cell culture model. The potential of the peptidomimetics to interact with biological membranes was estimated by IAM chromatography.

RESULTS

In the absence of cyclosporin A, apical (AP) to basolateral (BL) flux of all compounds studied was less than the flux determined in the opposite direction (i.e., BL-to-AP). The ratio of the apparent permeability coefficients (Papp) calculated for the BL-to-AP and AP-to-BL transport (P(BL-->AP)/P(AP-->BL)) varied between 1.7 and 36.2. When individual pairs were ompared, P(BL-->AP)/P(AP-BL) ratios of the pyrrolinone-containing compounds were 1.5 to 11.5 times greater than those determined for the amide bond-containing analogs. Addition of 25 microM cyclosporin A to the transport buffer reduced the P(BL-->AP)/P(AP-->BL) ratios for all protease inhibitors to a value close to unity. Under these conditions, the amide bond-containing peptidomimetics were at least 1.6 to 2.8 times more able to permeate Caco-2 cell monolayers than were the pyrrolinone-containing compounds. The intrinsic uptake characteristics into Caco-2 cells determined in the presence of 25 microM cyclosporin A were slightly greater for the amide bond-containing protease inhibitors than for the pyrrolinone-containing analogs. These uptake results are consistent with the transepithelial transport results determined across this in vitro model of the intestinal mucosa.

CONCLUSIONS

The amide bond-containing and pyrrolinone-based peptidomimetics are substrates for apically polarized efflux systems present in Caco-2 cell monolayers. The intrinsic permeabilities of the amide bond-containing protease inhibitors are slightly greater than the intrinsic permeabilities of the pyrrolinone-based analogs through Caco-2 cell monolayers.

Immunohistochemical evaluation of cholinergic neurons in the rat superior olivary complex

The cholinergic system in the rat superior olivary complex (SOC) was evaluated by immunohistochemistry for choline acetyltransferase (ChAT) and vesicular acetylcholine transporter (VAChT) and histochemistry for acetylcholinesterase (AChE). ChAT-positive somata were found mostly in the lateral superior olive (LSO) and ventral nucleus of the trapezoid body (VNTB). In the LSO, there were both rostral-caudal and medial-lateral gradients in concentration of ChAT-positive somata; the highest concentration was in the middle of the rostral-caudal extent and the most medial part. The estimated total number of ChAT-positive neurons in the LSO was similar to previous estimates of the total number of lateral olivocochlear neurons. Two groups of ChAT-positive somata were found in the VNTB: a dorsolateral group of larger, multipolar, and more darkly labeled neurons and a ventromedial group of smaller, oval, and more lightly labeled neurons, which was about 5 times as numerous. There was a caudal-to-rostral increase in number of neurons in each group. VAChT immunoreactivity, predominantly localized in puncta, was seen in LSO, VNTB, and LNTB, and, to a lesser extent, in other parts of the SOC. VAChT-positive somata were also found in the VNTB and medial LSO. This distribution pattern of VAChT was generally similar to that of ChAT. AChE labeling had a similar appearance to ChAT labeling in the VNTB but differed in the LSO, where AChE labeling was lighter and associated more with neuropil than with somata.

Modulation of receptor and receptor subtype affinities using diastereomeric and enantiomeric monosaccharide scaffolds as a means to structural and biological diversity. A new route to ether synthesis

We show that carbohydrates constitute an attractive source of readily available, stereochemically defined scaffolds for the facile attachment of side chains contained in genetically encoded and other amino acids. beta-D- and beta-L-glucose, L-mannose, and the 6-deoxy-6-N-analogue of beta-D-glucose have been employed to synthesize peptidomimetics that bind the SRIF receptors on AtT-20 mouse pituitary cells, five cloned human receptor subtypes (hSSTRs), and the NK-1 receptor. The affinity profile of various sugar-based ligands at the hSSTRs is compared with that of SRIF. Compound 19 bound hSSTR4 with a Ki of 100 nM. Subtle structural changes affect affinities. Evidence is presented that suggests that one compound (8) binds both the AtT-20 cell receptors and the five hSSTRs via a unique mode. The SARs of the glycosides at SRIF receptors differ markedly from those at the NK-1 receptor. For example a 4-benzyl substituent is important for SRIF receptor binding, but the 4-desbenzyl analogue 27 was highly potent (IC50 of 27 nM) at the NK-1 receptor. A new, nonbasic method for the synthesis of base-sensitive ethers from primary and secondary alcohols is also described.

Separate bisphosphatase domain of chicken liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase: the role of the C-terminal tail in modulating enzyme activity

The separate bisphosphatase domain (amino acid residues 243-468) of the chicken liver bifunctional enzyme 6-phosphofructo-2-kinase-fructose-2,6-bisphosphatase was expressed in Escherichia coli and purified to homogeneity. The fructose-2, 6-bisphosphatase activity of the separate domain was 7-fold higher than that of the native bifunctional enzyme, and exhibited substrate inhibition characteristic of the native enzyme. The inhibition of the enzymes by fructose 2,6-bisphosphate could be overcome by Pi, glycerol 3-phosphate and GTP. Deletion of 30 amino acid residues from the C-terminus of the separate domain resulted in around a 5-fold increase in the Vmax of the bisphosphatase. Also, the truncated form was more accessible to chemical modification by diethyl pyrocarbonate and N-ethylmaleimide, suggesting a more open structure than the wild-type form. In addition, the mutation of cysteine-389 to alanine increased bisphosphatase activity by 20% and the Km value for fructose 2,6-bisphosphate by 3-fold, and both the point mutation at cysteine-389 and the deletional mutation led to the predominantly insoluble expression of the enzyme. The results indicated that the C-terminal tail plays a role in modulating the enzyme activity and suggested that the difference in the C-terminal tail sequence is responsible for the difference in activity of the chicken and rat liver fructose-2,6-bisphosphatases. It is postulated that an interaction between the C-terminal tail and the active site might be present.

[Studies on the pharmacognosy of Cortex Illicii and its adulterants]

The traditional Chinese Medicine Cortex Illicii and its adulterants were studied on textual identification, botanical origin, morphological and histological characters. The TLC and UV spertra methods were established to separate and estimate Difengpin, Magnolol and beta-sitosterol in Cortex Illicii and its products.

Densitometric evaluation of markers for cholinergic transmission in rat superior olivary complex

Cholinergic transmission in the rat superior olivary complex (SOC) was assessed by densitometric measurements of labeling with several markers: acetylcholinesterase (AChE) histochemistry, choline acetyltransferase (ChAT) immunohistochemistry, and muscarinic acetylcholine receptor (M35) immunohistochemistry and N-methylscopolamine (NMS) binding autoradiography, as well as its subtype 2 (m2) immunohistochemistry. The markers which may occur in cholinergic neurons (ChAT, m2 receptor and AChE) showed dense labeling in the ventral nucleus of the trapezoid body (VNTB), in line with other evidence that it contains cholinergic neuron somata. The markers which are predominantly in cholinoceptive neurons (M35 and NMS) showed less labeling in the SOC, suggesting few muscarinic cholinergic inputs. These results are compared with those for the cochlear nucleus.

In vitro selection of packaging sites in a double-stranded RNA virus

The Saccharomyces cerevisiae double-stranded RNA virus ScVL1 recognizes a small sequence in the viral plus strand for both packaging and replication. Viral particles will bind to this viral binding sequence (VBS) with high affinity in vitro. An in vitro selection procedure has been used to optimize binding, and the sequences isolated have been analyzed for packaging and replication in vivo. The selected sequence consists of a stem with a bulged A residue topped by a loop of several bases. Four residues of the 18 bases are absolutely conserved for tight binding. These all fall in regions that appear to be single stranded. Eight more residues have preferred identities, and six of these are in the stem. The VBS is similar to the R17 bacteriophage coat protein binding site. Packaging and replication require tight binding to viral particles.

The effect of neuropeptides on vessel tone and cAMP production

The effect of VIP, PHM, PHV, PACAP-27, and PACAP-38 on vessel tone and cAMP production was investigated in rabbit ovarian arteries in vitro. The peptides (10(-7)M) induced a significant relaxation on NA-precontracted vessels and displayed similar potencies. The cAMP accumulation induced by PACAP-27 and PACAP-38 was five times higher than the cAMP content induced by VIP, PHM, and PHV. NPY (10(-7)M) markedly reversed the relaxations induced by VIP, PHM, PHV, PACAP-27, and PACAP-38 but did not at all affect the cAMP production induced by these peptides. We conclude that the relaxation induced by VIP, PHM, PHV, PACAP-27, and PACAP-38 and the contraction evoked by NPY are not solely related to the changes of cAMP contents, and that in addition to cAMP, another intracellular signal transduction pathway may be involved.

Immunolocalization of muscarinic acetylcholine subtype 2 receptors in rat cochlear nucleus

It has been suggested that cholinergic effects in the rat cochlear nucleus (CN) are mediated by muscarinic acetylcholine receptors. In this study, immunohistochemistry for muscarinic subtype 2 (m2) receptors using a monoclonal subtype-specific antibody (Levey et al. [1995] J. Comp. Neurol. 351:339-356) revealed an m2-like system in the rat CN. A prominent lamina of m2-immunoreactive fibers and puncta was located in a subgranular layer of the caudal anteroventral cochlear nucleus (AVCN) and the posteroventral cochlear nucleus (PVCN). The superficial granular layer of the rostral AVCN and the medial sheet region also contained notable immunoreactivity for m2. Some labeled somata and their processes were found in magnocellular regions of the ventral CN. A network of neurites and puncta was located in the fusiform soma and deep layers of the dorsal CN. The olivocochlear bundle and its branches to the CN were also m2 immunoreactive and possibly contributed m2-labeled fibers and terminals to the CN. Some similarities and some differences were found between this m2 receptor distribution pattern and previous results for choline acetyltransferase (ChAT), acetylcholinesterase (AChE), and muscarinic acetylcholine receptor immunohistochemistry and binding in the CN. The results suggest that m2 receptors that are located both pre- and postsynaptically mediate many cholinergic effects in the rat CN.

Synthesis of potent cyclic hexapeptide NK-1 antagonists. Use of a minilibrary in transforming a peptidal somatostatin receptor ligand into an NK-1 receptor ligand via a polyvalent peptidomimetic

The endogenous peptides somatostatin (SRIF) and substance P comprise very different structures. Although both bind G-protein-coupled receptors, the SRIF receptors (SSTR 1-5) recognize SRIF and related peptides which retain its beta-turn such as the potent cyclic hexapeptide SRIF agonist L-363,301 (6a), but not substance P. Conversely the NK-1 receptor binds substance P but not the above ligands. In contrast, the beta-D-glucosides 1 and 2, designed to mimic the beta-turn of 6a, bind both receptors. This observation led us to attempt the conversion of 6a into the first potent, selective cyclic hexapeptide ligand for the NK-1 receptor. To this end, we combined design with a minilibrary approach. The goal was accomplished with surprising ease, leading to the NK-1 receptor antagonist 9 (IC50 2.0 +/- 0.4 nM). This demonstrates that peptidomimetics, incorporating in this case the promiscuous beta-D-glucose scaffold, can provide valuable clues about receptor similarities not revealed by their endogenous ligands. In addition, this work suggests that the use of libraries and rational design need not be mutually exclusive approaches to lead discovery.

Vascular effects and cyclic AMP production produced by VIP, PHM, PHV, PACAP-27, PACAP-38, and NPY on rabbit ovarian artery

The relationship between vessel tone and cAMP production induced by vasoactive intestinal polypeptide (VIP), peptide histidine methionine (PHM), peptide histidine valine (PHV), pituitary adenylate cyclase activating polypeptide (PACAP-27 and PACAP-38), and neuropeptide Y (NPY) was investigated in rabbit ovarian arteries in vitro. VIP, PHM, PHV, PACAP-27, and PACAP-38 added in single-dose experiments (10(-9), 10(-8), 10(-7), and 10(-6) M) induced all a significant dose-related relaxation of noradrenaline (NA)-precontracted vessels and displayed similar potencies. VIP, PHM, PHV, PACAP-27, and PACAP-38 all increased cyclic adenosine monophosphate (cAMP) accumulation. The cAMP accumulation induced by PACAP-27 and PACAP-38 was five times higher than the cAMP content induced by the other three peptides. The peptide-induced smooth muscle relaxation did not correlate to the cAMP accumulation. NPY (10(-7) M) markedly reversed the relaxations induced by VIP, PHM, PHV, PACAP-27, and PACAP-38, but did not influence the cAMP production induced by these peptides. In conclusion, the relaxation induced by VIP, PHM, PHV, PACAP-27, and PACAP-38 and the contraction induced by NPY are not solely related to the changes of cAMP contents. These findings indicate that in addition to cAMP, another intracellular signal transduction pathway may be involved in the relaxation and contraction induced by these peptides in rabbit ovarian artery.

Interference with replication of two double-stranded RNA viruses by production of N-terminal fragments of capsid polypeptides

It is possible to interfere with the replication of a number of plant RNA viruses by systemic production of viral capsid polypeptides or RNA-dependent RNA polymerases, or by production of untranslatable portions of viral plus strands or minus strands. Interference can occur by a number of mechanisms. We have discovered that the Saccharomyces cerevisiae double-stranded RNA viruses ScVL1 and ScVLa, which exist as permanent persistent infections of their host cells, can be cured very efficiently by production of N-terminal fragments of their capsid polypeptides. These totiviruses produce only two polypeptides: a capsid polypeptide (Cap) and a Cap-Pol fusion polypeptide with RNA-dependent RNA polymerase activity. Three types of interference can be detected: interference due to overproduction of both Cap and Cap-Pol, interference due to overproduction of Cap (and consequent distortion of the Cap to Cap-Pol ratio), and interference due to negative complementation by N-terminal fragments of Cap. Some N-terminal fragments of Cap appear to be incorporated into viral particles, but only in the presence of a complete Cap protein. We postulate that incorporation of N-terminal fragments of Cap results in the formation of defective particles.

[Analysis of biochemical components of seminal plasma in male workers exposed to mercury vapor]

Determinations of transferrin (Tf), fructose (Fru), citric acid (CA), zinc (Zn) and copper (Cu) levels of seminal plasma in 38 male workers exposed to mercury vapor and 18 male unexposed controls showed levels of Tf and total Fru, and sperm density adjusted Fru level of seminal plasma in workers exposed were significantly lower than those in controls, and the latter lowered gradually with increase of exposure to mercury. No significant difference of levels of CA, Zn and Cu of seminal plasma between the two groups was found. It suggests chronic exposure to mercury vapor may cause adverse effects on Sertoli's cells of spermatogenic epithelium and seminal vesicle function.

Immunohistochemistry of muscarinic acetylcholine receptors in rat cochlear nucleus

Neurons of the cochlear nucleus (CN) receive extrinsic and intrinsic cholinergic inputs, the effects of which appear to be mediated primarily by muscarinic acetylcholine receptors (mAChRs). To investigate the distribution of mAChRs and the correlation of pre- and post-synaptic cholinergic markers in CN, we used a monoclonal anti-mAChR antibody (M35) and a monoclonal antibody against choline acetyltransferase (ChAT) to perform immunohistochemistry on rat brain sections, and we also carried out histochemistry for acetylcholinesterase (AChE) activity. The density distributions of ChAT immunohistochemistry and AChE activity histochemistry agreed well with previous quantitative measurements of the activity distributions of these enzymes. A generally close correlation between densities of M35 and ChAT immunoreactivities was found across subregions of rat CN. The localizations of M35 and ChAT immunoreactivities suggest that cholinergic synapses are mostly axosomatic in ventral CN and possibly mostly axodendritic in dorsal CN. Prominent differences in density and appearance between M35 immunoreactivity and AChE activity were found in the regions of the rat CN where granule cells predominate.

Packaging in a yeast double-stranded RNA virus

The yeast virus ScV-L1 has only two genes, cap and pol, which encode the capsid polypeptide and the viral polymerase, respectively. The second gene is translated only as a cap-pol fusion protein. This fusion protein is responsible for recognition of a specific small stem and loop region of the viral plus strands, of 19 to 31 bases in length, ensuring packaging specificity. We have used a related virus, ScV-La, which has about 29% codon identity with ScV-L1 in the most conserved region of the pol gene, to map the region in pol that is responsible for packaging L1. Characterization of a number of chimeric viral proteins that recognize L1 but have the La capsid region delimits the region necessary for recognition of L1 to a 76- to 82-codon portion of pol. In addition, we show that overproduction of the La capsid polypeptide results in curing of the ScV-La virus, analogous to the production of plants resistant to RNA viruses by virtue of systemic production of viral coat protein.