Nociceptin/orphanin FQ in spinal nociceptive mechanisms under normal and pathological conditions

Nociceptin and its receptor are present in dorsal spinal cord, indicating a possible role for this peptide in pain transmission. The majority of functional studies using behavioral and electrophysiological studies have shown that nociceptin applied at spinal level produces antinociception through pre- and post-synaptic mechanisms. The spinal inhibitory effect of nociceptin is not sensitive to antagonists of opioid receptors such as naloxone. Thus, nociceptin-induced antinociception is mediated by a novel mechanism independent of activation of classic opioid receptors. This has raised the possibility that agonists of the nociceptin receptor may represent a novel class of analgesics. Supporting this hypothesis, several groups have shown that intrathecal nociceptin alleviated hyperalgesic and allodynic responses in rats after inflammation or partial peripheral nerve injury. Electrophysiological studies have also indicated that the antinociceptive potency of spinal nociceptin is maintained or enhanced after nerve injury. It is concluded that the predominant action of nociceptin in the spinal cord appears to be inhibitory. The physiological role of nociceptin in spinal nociceptive mechanisms remains to be defined. Moreover, further evaluation of nociceptin as a new analgesic calls the development of non-peptide brain penetrating agents.

Intracerebroventricular infusion of nerve growth factor induces pain-like response in rats

New strategies have recently been developed where infusion of neurotrophic factors into the brain can rescue different neuronal populations. However, negative side effects have been observed in clinical trials infusing nerve growth factor (NGF) into the lateral ventricle in man, namely pain. Little is known about pain behavior in animals after intracerebroventricular (i.c.v.) neurotrophic injections. Thus, we have examined the effects of i.c.v. infusion of NGF for 2 weeks on the behavioral response of rats to mechanical, cold and heat stimulation. Seven micrograms/day of NGF elicited a significant decrease in vocalization threshold to mechanical stimulation and a significantly increased response to cold and heat stimuli as compared with control. The concentration of NGF in cerebrospinal fluid (CSF) was significantly increased as compared with non-allodynic rats. The enhanced responses to mechanical and heat, but not to cold, stimulation were significantly reduced by CP-99994, a selective antagonist to tachykinin NK-1 receptors. When NGF was infused into the brain parenchyma (striatum, cortex and septum) no allodynic nor hyperalgesic responses could be detected. These results indicate that in rats i.c.v. but not intraparenchymal infusion of NGF induce mechanical and cold allodynia as well as heat hyperalgesia, which is mediated, at least in part, by activation of NK-1 receptors.

Particulate concentration measured from scattered light fluctuations

Scintillation of scattered radiation caused by particulate matter is studied. By use of stochastic theory, expressions for mathematical expectation, variance, and scintillation index are derived. A method of measuring particulate-mass concentration with the scintillation index is proposed. The major advantage of this method is its insensitivity to lens contamination and particle-color change.

Electric-field-induced soft-mode hardening in SrTiO3 films

We have studied electric-field-induced Raman scattering in SrTiO3 thin films using an indium-tin-oxide/SrTiO3/SrRuO3 structure grown by pulsed laser deposition. The soft mode polarized along the field becomes Raman active. Experimental data for electric-field-induced hardening of the soft modes and the tuning of the static dielectric constant are in agreement described by the Lyddane-Sachs-Teller formalism. The markedly different behavior of the soft modes in thin films from that in the bulk is explained by the existence of local polar regions.

Effect of chronic AT(1) receptor blockade on cardiac Smad overexpression in hereditary cardiomyopathic hamsters

OBJECTIVE

As the pharmacological suppression of angiotensin has been associated with cardioprotective effects in cardiomyopathy, our primary aim was to determine whether the expression of Smad protein components of the cardiac TGF-beta signaling cascade is modulated by chronic AT(1) receptor blockade. Furthermore, we examined the relationship between cardiac Smad protein expression and altered collagen turnover in the cardiomyopathic heart.

METHODS

Male UM-X7. 1 cardiomyopathic (CMP) Syrian hamsters at early (65 days) and late (200 days) stages of cardiomyopathy were subjected to 4 week losartan (15 mg/kg/day) treatment. Expression of left ventricular (LV) receptor-activated (Smad 2) and common-mediator (Smad 4) Smads from control (F1-beta strain) hamsters, non-treated cardiomyopathic (CMP), and losartan-treated CMP animals was assessed. Collagen turnover, including fibrillar collagen synthesis/accretion and cardiac MMP activity was assessed.

RESULTS

Elevated mRNA abundance of fibrillar collagens and ANF were present in cardiomyopathic hearts and these trends were normalized in the early stage losartan-treated group. 4-Hydroxyproline and zymographic assays confirmed fibrosis and elevated MMP-1 and -2 activities in CMP hearts. Losartan treatment was associated with a modest reduction of cardiac 4-hydroxyproline concentration, and a significant reduction of both MMP-1 and MMP-2 activities. While TGF-beta(1) mRNAs were elevated in both CMP groups vs. controls, total TGF-beta protein content was not different in CMP vs. controls. In LV preparations containing nuclear extract, elevated Smad 2 and Smad 4 protein expression was noted in cardiomyopathic hearts vs. controls. Losartan treatment of late-stage CMP hamsters was associated with a significant reduction in Smad 2 and a modest reduction of Smad 4 protein expression vs. untreated CMP samples.

CONCLUSIONS

Altered cardiac Smad expression, present in both early and late stage cardiomyopathy, is positively correlated with the occurrence of cardiac fibrosis and elevated collagen turnover in failing CMP hearts. Four week AT(1) blockade is associated with normalized expression of cardiac Smad 2 proteins, and these changes occur in parallel with some aspects of collagen turnover in failing cardiomyopathic hearts.

Actions of bovine plasma fibronectin on cultured human dental pulp cells

OBJECTIVE

Fibronectin (FN) has been shown to play a crucial role in odontoblast differentiation, and it is involved in the repair of dentine and pulp. The responsiveness of human dental pulp (HDP) cells to bovine plasma FN was investigated.

MATERIALS AND METHODS

After isolation and selection noncarious freshly extracted third molars in vitro, HDP cells were incubated for 72 hours one of four concentrations (10, 20, 40, 80 micrograms/ml) of bovine plasma FN with Dulbecco's modified eagle medium (DMEM) containing 1% fetal calf serum (FCS). We examined cell proliferation (using an MTT assay), DNA synthesis (using incorporation of [3H]-thymidine), the cell area, and alkaline phosphatase (ALPase) activity of the culture supernatant. The expression of FN, types I and III collagens, binding of lectins concanavalin(ConA), or wheat germ agglutinin (WGA) in vitro was examined by means of immunocytochemistry. The expression degree and the cell area were analyzed semi-quantitatively with an image processing and analysis system.

RESULTS

After 72 hours, HDP cells appeared contracted and smaller in the absence of FN when compared to cells incubated with FN. HDP cells were in spread state with all four concentrations of FN. FN (20, 40 micrograms/ml) stimulated cell proliferation, promoted incorporation of [3H]-thymidine, and increased the levels of ALPase activity in supernatant. The binding of ConA, the expression of type I collagen, and FN were significantly increased, while the binding of WGA, and the expression of type III collagen were significantly decreased in the FN (40, 80 micrograms/ml) groups when compared to the FN (10, 20 micrograms/ml) groups.

CONCLUSION

These findings suggest that HDP cells utilize FN for attachment and subsequent spreading. FN might have mitogenic activity and some role in the regulation of differentiation of pulp cells into odontoblasts.

[Surgical correction of complete atrioventricular septal defect with tetralogy of Fallot]

OBJECTIVE

To report the surgical correction of complete atrioventricular septal defect with tetralogy of Fallot (AVSD-TOF).

METHODS

Six consecutive patients aged 3 - 9 years underwent correction of complete AVSD-TOF. The two-patch technique for atrioventricular septal defect was used. The ventricular septal defect was closed through a right ventriculotomy and right atriotomy in each case. The commissure between the superior and inferior bridging leaflets of the left portion of the common atrioventricular valve was closed in each patient. RVOT obstruction was relieved by a transannular autologous pericardium with monocuspid valve.

RESULTS

Postoperative complications included respiratory failure in 1 patient, low cardiac output syndrome in 1, and MOF in 1. There was one mortality because of MOF in the early postoperative period. Five survivors were followed up from 6 months to 5.5 years (mean 2.3 years). There was no late mortality and only one patient had mild left atrioventricular valve regurgitation. NYHA cardiac function was class I in 4 patients and class II in 1.

CONCLUSIONS

AVSD-TOF can be corrected using the two-patch technique and closure of the ventricular septal defect through a combined approach using a right ventriculotomy and right atriotomy. Routine closure of the commissure of the left portion of the atrioventricular valve results in a low incidence of regurgitation. Good functional result can be achieved in most patients postoperatively.

Critical loads of acidity for surface waters in China

For further control of acid rain and sulphur dioxide pollution, the Chinese government has designated the Acid Rain Control Zone and the Sulphur Dioxide Pollution Control Zone for those areas that are, or could become, affected by acid deposition or ambient sulphur dioxide concentrations. One of the most important principles for designating the Acid Rain Control Zone is that the critical load is exceeded by the sulphur deposition. Through the steady-state water chemistry method (SSWC), critical loads of acidity for surface waters were mapped based on available data. Results show that surface waters sensitive to acid deposition, i.e. surface waters with low critical loads, are mainly found in north-east China, on the Tibetan Plateau, and in north-west China. Compared with the critical loads of soils, critical loads of surface waters are usually higher in almost all areas in China. The reason for very low critical loads of surface waters in some regions dominated by soils geologically not sensitive to acid deposition may be attributed to the low temperature, high altitude and low runoff. In contrast, surface waters in south China are not susceptible to acid deposition, and so far acidification of surface water has not been found in spite of the heavy acid rain. As can be seen from the critical load exceedance map, nearly 10% of the surface waters are subject to risk of acidification in 1995.

Screening of novel epilepsy-related genes and isolation and identification of cDNAs

Twenty cDNA differential fragments were isolated from the hippocampus of rats in epileptic state using mRNA differential display technique. Four fragments were sequenced and compared with the known sequences in the Genebank, which showed that ERG8, ERG11, ERG12 had no significant identity to any known sequences; ERG14 had 64%-69% identity to microtubulin-associated protein of the rat. Because the differential expression of these genes was caused by epilepsy inducer coriaria lactone (CL) and anti-epilepsy drug MK-801 and ERG8 might be a novel candidate epilepsy gene; ERG11 and ERG12 might be novel candidate anti-epilepsy genes. Since the microtubulin-associated protein is closely associated with the collateral sprouting of mossy fibers in the hippocampus of seizured rat, the high expression of ERG14 in the early stage of epilepsy might predict the growth of axon and formation of synapse.

[Effect on keratocyte-mediated collagen degradation by Pseudomonas aeruginosa]

OBJECTIVE

To study the pathogenesis of cornea melting (ulceration) by pseudomona (P) aeruginosa for instruction of clinical treatment.

METHODS

Type I collagen gels with or without suspended keratocytes were incubated for 24 hours under medium containing sterile P. aeruginosa culture broth. Native collagen fibrils were removed from the media by ultrafiltration. The ultrafiltrates were then hydrolyzed, and the amount of hydroxyproline was measured spectrophotometrically. The effect of a synthetic matrix metalloproteinase (MMP) inhibitor, Galardin, on collagen degradation was also examined.

RESULTS

P. aeruginosa broth induced type I collagen gel degradation directly. In the presence of keratocytes, degradation by P. aeruginosa broth was enhanced. Galardin significantly reduced the amount of collagen degraded by P. aeruginosa culture broth, no matter keratocytes were present or not.

CONCLUSION

P. aeruginosa culture broth directly degrades type I collagen and also increases keratocyte-mediated collagen degradation. The result is helpful to the clinical treatment of cornea melting caused by P. aeruginosa, and the mechanism should be further studied.

The effect of coriaria lactone on NMDA receptor mediated currents in rat hippocampal CA1 neurons

To investigate the exact mechanism of epileptogenesis induced by coriaria lactone (CL), the effect of CL on NMDA receptor mediated current (IAsp) in rat hippocampal CA1 neurons was investigated by using nystatin perforated whole-cell patch clamp. 10(-6)-10(-4) mol/L Asp acted on NMDA receptors and elicited an inward current (IAsp) at a holding potential (VH) of -40 mV in presence of 10(-6) mol/L glycine and absence of Mg2+ extracellularly. CL enhanced NMDA receptor mediated current induced by Asp, but had no effect on threshold concentration, EC50, Hill coefficient as well as maximal-effect concentration and reversal potential of IAsp. The effect had no relationship with holding potential. These results showed that CL could enhance NMDA receptor mediated current to increase [Ca2+]i of neurons by acting on Gly site, thereby inducing epilepsy.

[Modified total cavopulmonary connection for treating patients with functional single ventricle]

OBJECTIVE

To modify the classic procedure for better surgical results of total cavopulmonary connection (TCPC).

METHODS

Modified TCPC was performed in 13 patients with functional single ventricle. In the modified TCPC procedure, the distal end of the superior vena cava (SVC) was connected with the upper edge of the right pulmonary artery (RPA) with the anastomosis orifice near the left side, and the proximal end with the lower edge of RPA with the anastomosis orifice near the right side. Among them, intra-atrial tunnel was established with a partial tube of PTFE using the lateral tunnel technique in 8 patients, and the distal end of the inferior vena cava (IVC) was directly connected with the lower edge of RPA using extracardiac conduit in the beating heart in 5.

RESULTS

One patient (7.7%) died early. Twelve patients survived and had the SatO(2) (94.6 +/- 1.2)% postoperatively while inspiring air. Angiography showed that most blood from IVC enters the right lung and most blood from SVC the left lung. No late mortality was seen during the follow up for 6 months to 2 years and 2 months. NYHA class I was noted in 10 patients and class II in 2. Echocardiography showed that left ventricular volume reduced significantly and ventricular function was normal.

CONCLUSIONS

Modified TCPC produces optimal blood flow between the two lungs, elevates postoperative Sat O(2) effectively, decreases ventricular volume load and improves ventricular functions.

[A study on hemostatic and immunological actions of fresh and dry Dihuang]

OBJECTIVE

To investigate the difference between fresh and dry Dihuang (Radix Rehmanniae) in hemostatic and immunological actions.

METHODS

The hemostatic action was assessed in aspirin-treated mice; immunological action was assessed by phagocytosis of macrophages in dexamethasone-treated mice; and Con A-induced mitogenesis and LPS-induced alkaline phosphatase activity of splenocytes were determined in thyroxin-treated mice.

RESULT

The blood clotting in mice induced by aspirin was inhibited by oral administrations of juice decoction of fresh Dihuang or decoction of dry Dihuang alike. The action of fresh Dihuang juice was stronger than that of dry Dihuang decoction. Oral administrarion of fresh Dihuang juice or decoction for 10 days enhanced LPS-induced alkaline phosphatase activity of splenocytes in thyroxin-treated mice. The juice also enhanced Con A-induced splenocyte mitogenesis. The action of dry Dihuang decoction was weaker than that of fresh juice in increasing LPS-induced alkaline phosphatase activity.

CONCLUSION

It is recommended to follow the tradition of using fresh Dihuang juice or decoction to treat some diseases such as hemorrhagenic troubles.

[Cloning and partially sequencing of mouse dentin sialophosphoprotein encoding mature protein]

OBJECTIVE

Cloning and partially sequencing of mouse dentin sialophosphoprotein (DSPP) encoding mature protein.

METHODS

Total RNA was extracted from the tooth germs of newborn mouse by acid guanidinium thiocyanata-phenol-chloroform method, the desired DNA product was obtained from the total RNA by RT-PCR with the primers including Oligo(dt) and two gene specific primers. The segment (about 3 Kbp) was inserted into pBluescript vector and the interesting plasmid was transformed into E. Coli host strain XL1-Blue. The double-stranded DNA of the positive clone was analyzed by restriction endonuclease mapping and DNA sequencing.

RESULTS

The restriction endonuclease map and sequence of mouse DSPP encoding mature protein were consistent with those of the published.

CONCLUSION

The mouse DSPP cDNA encoding mature protein was obtained for further study.

[Prevention of postoperative recurrence of bladder cancer: a clinical study]

OBJECTIVE

To lower postoperative recurrence rate of bladder cancer, the prophylactic effects of five kinds of method on bladder cancer were evaluated.

METHODS

Between 1982 and 1997, 313 patients after TURBT or partial cystectomy were followed up for 2 to 15 years (average 7.6 years). These patients were divided into six groups: BCG, mitomycin C (MMC), thiotepa, Chinese herb medicine Zhuling (Grifola umbellata pilat), afterloading brachytherapy and control group. The prophylactic effects of them on postoperative recurrence of bladder cancer was evaluated.

RESULTS

During the follow-up, the recurrence rates were 35.1% in BCG group, 34.9% in Zhuling group, 41.7% in MMC group, 52.6% in thiotepa group, 64.7% in control group, respectively. 25 high-risk patients with invading or multiple bladder cancer were treated by afterloading brachytherapy. They were followed up from 12 to 42 months, with a recurrence rate being 24.0%.

CONCLUSIONS

The prophylactic effect of Zhuling and BCG on bladder cancer recurrence was better than MMC. The vale of thiotepa was not significant. The afterloading brachytherapy was of great vale to invading or recurrent, multiple bladder cancer.

Genetic studies on a family with acute myelogenous leukemia

Seven cases of myelogenous leukemia--two acute erythroleukemia (AEL), four acute myelogenous leukemia (AML), and one acute myelomonocytic leukemia (AMMoL)--were found in 22 members of three consecutive generations of a family in the past 16 years (1973-1989). By using cytogenetic, hematologic, and biochemical analyses of those surviving in this family, we also found four members who might develop leukemia in the future. Southern blot analysis of one of the four members and her father (an acute leukemia patient) with a v-ERBB probe showed that the gene abnormalities consisted of a c-ERBB rearrangement (hereditary) and a rearrangement/amplification of the same gene.

[Effect of fodder components on the product of obese gene expression--leptin in rats]

OBJECTIVE

To study the effects of different fodder components and levels of caloric uptake on the product of obese gene expression -- leptin and in vivo secretion of insulin and growth hormone, and to study the relationship between them in rats.

METHODS

Plasma leptin was determined by Western blot, and serum insulin and growth hormone were determined by radioimmunoassay (RIA).

RESULTS

There was no significant effects of fodder components, including high protein, fat and carbohydrate, on the levels of leptin, insulin and growth hormone in rats, with the same caloric uptake in them. However, with the higher caloric uptake, level of obese gene expression increased, showing increased levels of plasma leptin and serum insulin and decreased level of serum growth hormone.

CONCLUSION

There could existed an interaction between expression of obese gene and secretions of leptin, insulin and growth hormone, which could be modified by the same metabolic signal.

[The effects of basic fibroblast growth factor on proliferation and differentiation of human dental pulp cells in vitro]

OBJECTIVE

To evaluate the effects of human basic fibroblast growth factor (hbFGF) on proliferation and differentiation of human dental pulp cells in vitro.

METHODS

The syntheses of DNA, collagen, fibronection (FN), alkaline phosphatase (ALP) and bone morphogenetic protein (BMP), and the expression of agglutinin were measured with imagine processing and analysis system.

RESULTS

hbFGF at concentration of 1-10 micrograms/L stimulated the cell proliferation measured by MTT colorimetric assay, and promoted incorporation of 3H-thymidine at 1-100 micrograms/L. The expression of type I collagen, FN, Con A receptor, and ALP significantly increased at hbFGF concentration of 10-1,000 micrograms/L, but the expression of type III collagen and WGA receptor markedly decreased at the same concentration. There was no significant difference in expression of BMP.

CONCLUSION

bFGF has the capability to promote the differentiation of dental pulp cells to odontoblasts in culture.

[The effect of combined endocrine therapy on prostate and testis]

OBJECTIVE

To study the pathological changes of the effect of combined endocrine therapy on normal prostate, benign prostatic hyperplasia, prostatic adenocarcinoma and testis.

METHODS

11 radical prostatectomy specimens, 3 core-needle biopsies of prostate and 3 testes obtained after at least 3 months of enatone-flutamide inhibition therapy were studied. Step-section was performed on radical specimens and average 16 sections per case were reviewed. PSA, PSAP and AE1/AE3 were immunostained on 14 cases of prostate cancer and a comparative study pre- and post-treatment was made.

RESULTS

No residual tumor was recognized in 2 cases. Such characteristic changes were found in 9 cases as prominent acinar atrophy, decreased ratio of acini to stroma, stromal fibrosis, squamous metaplasia of carcinoma, cytoplasmic vaculation, nuclear shrinkage, and nucleolar shrinkage. No apparent change was discovered in 3 cases. Secretory epithelial atrophy and basal cell hyperplasia were the popular change in BPH and normal prostate. The expressions of both PSA and PSAP were markedly reduced in prostate carcinoma and nonneoplastic glands. Pathological downstaging of the tumor was not found statistically. Epithelial atrophy also existed in seminal vesicles and Leydig cells of the testes after hormone therapy.

CONCLUSIONS

Combined endocrine therapy results in histologically distinctive changes that can be found in both nonneoplastic and neoplastic prostate tissue. However, the drugs can not eradicate prostate cancer completely. Testis atrophy is the direct action of the therapy.

Elevation of expression of Smads 2, 3, and 4, decorin and TGF-beta in the chronic phase of myocardial infarct scar healing

We have previously shown that non-myocytes present in healed 8-week infarct scar overexpress transduction proteins required for initiating the elevated deposition of structural matrix proteins in this tissue. Other work suggests that TGF-beta 1 may be involved in cardiac fibrosis and myocyte hypertrophy. However, the significance of the altered TGF-beta signaling in heart failure in the chronic phase of post-myocardial infarction (MI), particularly in the ongoing remodeling of the infarct scar, remains unexplored. Patterns of cardiac TGF beta 1 and Smad 2, 3, and 4 protein expression were investigated 8 weeks after MI and were compared to relative collagen deposition in border tissues (containing remnent myocytes) and the infarct scar (non-myocytes). Both TGF-beta 1 mRNA abundance and protein levels were significantly increased in the infarct scar v control values, and this trend was positively correlated to increased collagen type I expression. Cardiac Smad 2, 3, and 4 proteins were significantly increased in border and scar tissues v control values. Immunofluorescent studies indicated that Smad proteins localized proximal to the cellular nuclei present in the infarct scar. Decorin mRNA abundance was elevated in border and infarct scar, and the pattern of decorin immunostaining was markedly altered in remote remnant heart and scar v staining patterns of control sections. Expression of T beta RI (53 kDa) protein was significantly reduced in the scar, while the 75 kDa and 110 kDa isoforms of T beta RII were unchanged and significantly increased in scar, respectively. These results indicate that TGF-beta/Smad signaling may be involved in the remodeling of the infarct scar after the completion of wound healing per se, via ongoing stimulation of matrix deposition.

Expression of Gi-2 alpha and Gs alpha in myofibroblasts localized to the infarct scar in heart failure due to myocardial infarction

OBJECTIVE

Patients surviving large transmural myocardial infarction (MI) are at risk for congestive heart failure with attendant alteration of ventricular geometry and scar remodeling. Altered Gi-2 alpha and Gs alpha protein expression may be involved in cardiac remodeling associated with heart failure, however their expression in scar tissue remains unclear.

METHODS

MI was produced in Sprague-Dawley rats by ligation of the left coronary artery. Gi-2 alpha and Gs alpha protein concentration, localization and mRNA abundance were noted in surviving left ventricle remote to the infarct, in border and in scar tissues from 8 week post-MI hearts with moderate heart failure.

RESULTS

We observed a 4.5- and 5.0-fold increase in immunoreactive Gi-2 alpha protein concentration occurs in the border and scar regions vs. control values, respectively, in 8-week post-MI rat hearts. Similarly, immunoreactive Gs alpha protein concentration was increased 3.4- and 8.2-fold, respectively, in these tissues vs. controls. Double-fluorescence labeling and phenotyping studies revealed that both Gi-2 alpha and Gs alpha proteins were localized to myofibroblasts in the infarct scar and to viable myocytes bordering the scar. Northern analysis revealed that the Gi-2 alpha/GAPDH ratio was increased in both viable and scar regions (1.24- and 1.85-fold respectively) from experimental hearts when compared to sham-operated control values when compared to noninfarcted left ventricle, the value of this ratio in scar tissue was elevated approximately 1.5 fold. The Gs alpha/GAPDH ratio was significantly increased (1.28-fold) only in the scar region vs. control.

CONCLUSION

Our results indicate a marked increase in the expression of Gi-2 alpha and Gs alpha from myofibroblasts of the infarct scar as well as remnant myocytes bordering the scar in 8-week post-MI rat hearts. We suggest that these changes may be associated with ongoing remodeling in the infarct scar in chronic post-MI phase of this experimental model.

[Malignant pheochromocytoma: diagnosis and treatment]

OBJECTIVE

To review the experience with the diagnosis and treatment of malignant pheochromocytoma.

METHODS

Between 1986 and 1996, 7 patients with malignant pheochromocytoma were analysed.

RESULTS

Compared with benign pheochromocytoma of adrenal gland, the malignant one usually exceeded 7.0 cm in diameter, irregular in shape, invading the surrounding tissue and the normal structure of the effected adrenal gland disappeared. Bleeding and necrotic area were seen in tumor mass, even seemed as a cystic lesion with thick wall. In some patients, blood catecholamine and urine VMA significantly elevated without hypertension. The separating phenomenon and progressive weight loss, accelerated ESR were characteristics of malignant pheochromocytoma.

CONCLUSIONS

In some patients with malignant pheochromocytoma, histological findings are not consistent with their biological behaviors. Follow-up studies is mandatory in malignant pheochromocytoma as well as in benign one. Recurrence and/or metastasis after operation often occur in patients with malignant pheochromocytoma. In addition to early diagnosis and surgery, radiotherapy of tumor bed and systematic chemotherapy should be emphasized.

[A clinical study on solute removal index as an index to quantitate the adequacy of hemodialysis]

OBJECTIVE

In order to find a proper hemodialysis dosage and improve the life quality of the patients undergoing hemodialysis.

METHODS

A clinical study of solute removal index (SRI) was performed in 20 stable maintenance hemodialysis patients. Plasma BUN level was tested before and at the end of hemodialysis as well as 1 hr post-hemodialysis. Urea regeneration rate (G), protein catabolic rate (PCR), solute removal amount (R) and SRI were calculated by double-pool urea kinetic model.

RESULTS

It is shown that urea rebound rate was (18.50 +/- 3.35)% 1 hr post-hemodialysis, R was (13.82 +/- 5.48)g, G was (4.85 +/- 1.39)g, PCR was (0.94 +/- 0.29)g x kg(-1) x d(-1), SRI was (71.33 +/- 6.80)% respectively.

CONCLUSION

The results indicated that SRI is a better index to quantitate the adequacy of hemodialysis.

Coexistence of immune-neuro-endocrine substances in the rat central neurons

To investigate the expression of interleukin-2 (IL-2), metabotropic glutamate receptor subunit 1 (mGluR1) and estrogen receptor (ER) in neurons of the rat central nervous system (CNS) and identify the coexistence possibility of these immune-neuro-endocrine substances in the central neurons, the tri-labeling immunocytochemical technique with different species-specific primary antibodies (goat anti-IL-2 antibody, rabbit anti-mGluR1 antibody and mouse anti-ER antibody) were used to incubate two serial neighbor sections (one for demonstrating IL-2, another for mGluR1 and ER) of the cerebral cortex, medulla oblongata and spinal cord. There were IL-2-, mGluR1- and ER-immunoreactivity (IR)-positive labeled neurons in the above-mentioned central areas. The IL-2-IR production showed brown color, located in the cytoplasm; In the neighbor serial section, the mGluR1-IR, production showed blue-black color, located on the cell membrane; the ER-IR production also showed brown color, located in the cytoplasm and nuclei. There were mGluR1/ER double-labeled cells in the same section, which accounted for about 50%-60% of the total single and double labeled neurons. It was identified by projection check of serial neighbor sections that had mGluR1/ER/IL-2 tri-labeled cells, which accounted for about 30% of total mGluR1/ER double-labeled neurons. The results indicate that mGluR1, ER and Il-2 can coexist in the same rat central neurons, therefore, providing morphological basis for the theory about immune-neuro-endocrine network at the cellular level for the first time.

Antiproliferative and antifibrotic effects of mimosine on adult cardiac fibroblasts

Prolyl 4-hydroxylase catalyzes the hydroxylation of collagen pro-alpha chains for the deposition of cardiac collagen. The effect of prolyl 4-hydroxylase on synthesis and degradation of collagen was studied in cultured adult cardiac fibroblasts using mimosine, a prolyl 4-hydroxylase inhibitor. Mimosine inhibited [3H]thymidine incorporation in cultured fibroblasts in a dose-dependent manner (100-600 microM). Immunofluorescence in fibroblasts and biochemical detection of mature type I collagen in culture serum revealed a strong inhibition of synthesis and secretion of mature collagens, respectively, in the presence of 200 microM mimosine. Western blot analysis for procollagen was carried out in cultured fibroblasts, and 200 microM mimosine treatment was associated with increased intracellular accumulation of procollagen from 4.14+/-0.27 to 10. 19+/-0.37 (arbitrary units). Immunofluorescence studies confirmed a marked increase of intracellular procollagens in fibroblasts treated with mimosine, which suggests a loss of coordinated monomeric procollagen synthesis and secretion of triple helical mature collagens. Modest inhibition of collagen type I mRNA abundance was observed in mimosine-treated fibroblasts, whereas no effect was noted for mRNAs of collagen type III, alpha-prolyl 4-hydroxylase or beta-prolyl 4-hydroxylase when compared to untreated control values. Treatment of fibroblasts with 200 microM mimosine was associated with elevation of matrix metalloproteinase (MMP)-9 activity. The cytotoxicity of mimosine treatment was found minimal at the concentrations indicated above. Thus the antifibrotic effects induced by mimosine on cultured adult cardiac fibroblasts was associated with inhibition of prolyl 4-hydroxylase and diminished extracellular secretion of procollagen, despite the reactive elevation of intracellular procollagen synthesis. We suggest that specific inhibition of prolyl 4-hydroxylase may provide a novel therapeutic approach for the modulation of cardiac fibrosis.

[Effect of bovine plasma fibronectin on rat papilla cells in vitro]

OBJECTIVE

To observe the effect of exogenous fibronectin (FN) on the rat dental papilla tissues and cells.

METHODS

Tooth germs of first mandibular molars obtained from 17-day-old rat (SD) embryos were cultured for 3, 6, 9 days on millipore filters in DMEM supplemented with 10% FCS, 50 mg/L Vitamin c. The dental papilla were isolated by trypsin treatment of homologous tooth germs and cultured on uncoated (control) and FN coated millipore filters for 3, 6 days, bovine plasma FN deposited on millpore filters by treated for 2 hours with 80 mg/L FN.

RESULTS

As shown by histological and cytological data, some mesenchymal cells differentiated into odontoblasts and deposited predentine in cultured tooth germs. In cultured dental papillas, polarized functional cells were observed in FN coated group, odontoblast-like cells never differentiated in control cultures.

CONCLUSION

FN may be involved in odontoblast polarization.

Visualization of penicillin-binding proteins during sporulation of Streptomyces griseus

We used fluorescein-tagged beta-lactam antibiotics to visualize penicillin-binding proteins (PBPs) in sporulating cultures of Streptomyces griseus. Six PBPs were identified in membranes prepared from growing and sporulating cultures. The binding activity of an 85-kDa PBP increased fourfold by 10 to 12 h of sporulation, at which time the sporulation septa were formed. Cefoxitin inhibited the interaction of the fluorescein-tagged antibiotics with the 85-kDa PBP and also prevented septum formation during sporulation but not during vegetative growth. The 85-kDa PBP, which was the predominant PBP in membranes of cells that were undergoing septation, preferentially bound fluorescein-6-aminopenicillanic acid (Flu-APA). Fluorescence microscopy showed that the sporulation septa were specifically labeled by Flu-APA; this interaction was blocked by prior exposure of the cells to cefoxitin at a concentration that interfered with septation. We hypothesize that the 85-kDa PBP is involved in septum formation during sporulation of S. griseus.

[The use of laparoscopy in urology: report of 141 cases]

OBJECTIVE

To modify laparoscopy in urology.

METHOD

From May 1992 to Nov. 1996, 141 patients (110 males and 31 females) were subjected to laparoscopy in the treatment of urological diseases. The age of the patients ranged from 9 to 76 years (mean 39 years). Five patients had nephrectomy, 12 adrenalectomy, 48 renal cyst resection, 61 high ligation of internal spermatic vein, 5 pelvic staging lymphadenectomy, 9 orchiectomy, and 1 removal of bladder diverticulum.

RESULT

The rate of successful operation was 95.7% and that of complications was 2.22%. The mean hospitalization was 4.9 +/- 4.1 days.

CONCLUSION

Laparoscopy can be used widely in clinical practice.

[Analysis of blood flow in ophthalmic arteries in patients with middle and late stages of glaucoma with Doppler sonography]

OBJECTIVE

To understand the actual blood flow in cases with middle and late stages of glaucoma and the role of vascular factor in the deterioration of visual function in such patients.

METHODS

The blood flow in ophthalmic arteries was determined with color Doppler sonography (CDS) in 156 cases of patients with middle and late stages of glaucoma as well as in 75 cases of normal individuals as controls.

RESULTS

The average peak systolic velocity (PSV) and end diastolic velocity (EDV) of ophthalmic artery in normal control are 35.98 +/- 9.13 cm/s and 11.98 +/- 3.90 cm/s; the PSV and EDV in primary open-angle glaucoma (POAG) group are 24.13 +/- 4.65 cm/s and 7.10 +/- 1.85 cm/s; and in primary close-angle glaucoma (PCAG) group are 22.89 +/- 5.43 cm/s and 7.06 +/- 1.92 cm/s, respectively. No significant difference was found between POAG group and PCAG group (P > 0.05). However, significant differences were shown between normal group and patients with glaucoma for both PSV and EDV (P < 0.01).

CONCLUSION

The blood flow in ophthalmic arteries in patients with middle and late stages of glaucoma decreases significantly and the disorder in local blood circulation is evident, that is highly related to the deterioration of visual function and supports the vascular factor theory in the pathogenesis of glaucoma.

[Studies on GBV-C infection in blood donors in four provinces of China]

Plasma antibody against GBV-C (anti-GBV-C) and GBV-C RNA were detected with enzyme immunoassay (EIA) and reverse transcription nested polymerase chain reaction (RT-nPCR) in blood donors to study the prevalence of GBV-C infection in blood donors. Positivity of anti-GBV-C was 4.92 percent in 1,200 plasma donors (59/1,200), and that of GBV-C RNA was 64.41 percent in those with positive anti-GBV-C (38/59). Positivity of anti-GBV-C was 2.86 percent in 350 whole blood donors (10/350) and that of GBV-C RNA was 60.00 percent in those with positive anti-GBV-C (6/10). Positive rate of anti-GBV-C in those who donated blood for more than 10 years was higher than in control group. It suggests that infection with GBV-C was more often in plasma and blood donors. There were blood donors with positive GBV-C RNA but normal ALT activities and those both positive in GBV-C RNA and HCV RNA. It is urgent to detect the markers of GBV-C infection in blood donors as soon as possible.

Mineralized nodule formation by human dental papilla cells in culture

Human dental papilla cells were enzymatically separated from deciduous tooth germs of an 8-month-old embryo legally aborted. The second passage cells were cultured up to 35 days in 3 groups. The beta-GP group was cultured in the Dulbecco MEM containing ascorbic acid and beta-glycerophosphate supplemented with 15% fetal bovine serum. The Dex group was in the same medium, in addition containing dexamethasone. The control group contained none of the 3 chemicals. Mineralized nodules were formed after 15 days in the beta-GP and Dex groups. Only in the presence of ascorbic acid and organic phosphate did they mineralize. The addition of dexamethasone caused a significant increase in the number of nodules. By electron microscopy, the nodules contained needle-shaped crystals associated with a network of collagen fibrils. Calcium and phosphorus were detected by energy-dispersive X-ray microanalysis in the nodules. Furthermore, the crystalline material exhibited a pattern consistent with hydroxyapatite and dentin when examined by X-ray diffractometry. Cells showed high levels of alkaline phosphatase activity, which was increased 2-3 times in the presence of the 3 chemicals. These results indicated that human dental papilla cells have the ability to form dentin in culture. The formation of mineralized nodules by human dental papilla in vitro provides a useful model for studying the morphogenesis and differentiation of dental papilla ectomesenchyme.

Determination of Association Constants for Cyclodextrin-Surfactant Inclusion Complexes: A Numerical Method Based on Surface Tension Measurements

Inclusion complexes of beta-cyclodextrin (beta-CD) with sodium octyl sulfonate (C8As), sodium dodecyl sulfonate (C12As), and sodium hexadecyl sulfonate (C16As) in aqueous solutions are studied by surface tension measurement at the air/water interface at different temperatures. At fixed concentrations of the surfactants, the surface tension increases with an increase in beta-CD concentration to a maximum value, at which it holds. The surface tension curves of the surfactants in the presence of beta-CD are higher than those in the absence of beta-CD. The curves rise higher with the increase in beta-CD concentration for each surfactant. The apparent critical micelle concentrations (CMC*) of the surfactants vary linearly with beta-CD concentration. The CMC* and surface tension values (including those after the CMC*) for the same system decrease with increase in temperature. A numerical method based on surface tension measurements is developed to determine the association constants for 1:1 inclusion complexes. This method is very reliable and easy to perform. The results demonstrate that the longer the hydrophobic tail of the surfactant, the greater the association constant with beta-CD, and that for the same surfactant the association constant is higher at lower temperatures.

[Reoperations on prosthetic heart valves: an analysis of 64 cases]

During the period of Fabruary 1988 to May 1996, 64 reoperations were performed for prosthetic valve malfunction. Degeneration of bioprosthesis occurred in 46 patients, failure of mechanical prosthesis in 9, and periprosthetic leakage without evidence of infection in 9. In accordance with the status of cardiac function, 9 patients with acute dysfunction of mechanical prosthesis received emergency operations, and the remaining 55 patients with bioprosthetic valve failure or periprosthetic leakage received selective operation. There were 8 early deaths with a overall hsopital mortality rate of 12.5%. Three of the deaths occurred among the 55 selective procedures for a mortality of 5.3% and 3 of the deaths occurred among the 9 emergence procedures for mortality of 33.3%. The 56 long-term survivors were followed up from 3 months to 7 years (mean 2.1 years). There were 3 late deaths (5.3%). Forty-eight patients have been living more than 1 year. Their cardiac function after reoperation was class I (42 patients), class II (5), and class III (1). The timing of reoperation and surgical technique were discussed.

[Clinical study on myxoma and chordoma in the skull base]

OBJECTIVE

The clinical manifestation, neuroimaging properties, and pathologic changes of myxoma and chordoma were studied.

METHODS

Their neuroimaging properties and pathologic changes of myxoma 7 cases and chordoma 13 cases were analyzed.

RESULTS

(1) Clinical manifestation: the injury of oculomotor nerve and exorbitism is dominant in myxoma, but the injury of posterior cranial nerves is dominant in chordomas. (2) Plain skull X-ray film: local irregular punctate calcification and osseous necrosis were common in myxoma. Clivus invasion moruloid calcification and cauliflower-like calcification are always seen in chordoma. (3) CT and MRI: Location of the tumor and their relations with the adjacent structure were clear. (4) Pathologic changes: Cells are punctately arranged in myxoma, and vesicularly arranged in chordoma.

CONCLUSION

The clinical study of myxoma and chordoma is not only useful for their differiental diagnosis, but can provide valuable clues for their surgical approach as well.

Differential expression of cytokeratin mRNA and protein in normal prostate, prostatic intraepithelial neoplasia, and invasive carcinoma

The expression of cytokeratin (CK) mRNA for CK5, -8, -14, -16, and -19 was investigated in normal prostate, prostatic intraepithelial neoplasia (PIN) lesions, and invasive carcinoma using in situ hybridization. Protein localization was carried out in adjacent sections using immunohistochemistry and correlated with mRNA expression. Snap-frozen human prostate samples including 22 examples of normal glands, 20 cases of PIN lesions, and 12 cases of invasive carcinoma were examined. CK5 and -14 mRNA and protein were prominently expressed only in the basal cells of normal glands and PIN lesions. CK14 mRNA was absent in the luminal cells of the most of the PIN lesions but was seen at a low level in some PIN lesions. CK14 protein was not detected in any PIN lesion, suggesting that, if the cell that makes up the PIN lesions is derived from a basal cell, CK14 translation is depressed although a low level of CK14 mRNA may persist. CK8 mRNA and protein were constitutively expressed in all epithelia of normal and abnormal prostate tissues. CK19 mRNA and protein were persistently expressed in both basal and luminal cells of the tubular portion of normal glands as well as PIN lesions, but were expressed heterogeneously in both basal and luminal cells of normal alveoli. CK16 mRNA was expressed in a similar pattern as CK19, but CK16 protein was not detected either in normal or in abnormal prostate tissues. In conclusion, the expression of CK19 in PIN lesions is similar to its tubular expression and would support an origin of PIN lesions from this structure rather than the alveolar portion of the glands. The similar cytokeratin expression between PIN lesions and invasive carcinoma further supports the concept that PIN is a precursor lesion of invasive carcinoma.

Differential expression of laminin 5 (alpha 3 beta 3 gamma 2) by human malignant and normal prostate

Laminin 5 is an extracellular matrix protein integral to the formation of the hemidesmosomes that attach normal basal cells to the underlying basal lamina. We have shown that these hemidesmosomal complexes are lost in prostate carcinoma, possibly allowing malignant cells to detach from the anchoring structures and then to invade and migrate through the adjacent tissue. Our previous immunohistochemical studies of normal and malignant human prostate tissue demonstrated that the laminin subchains alpha 1, alpha 2, beta 1, beta 2, gamma 1, and gamma 2 were all expressed as normal components of the basal lamina surrounding prostate glands. Although most of these subchains were also expressed by the de novo basal lamina synthesized by prostate carcinoma, the gamma 2 subchain of laminin 5 was not detected. In an effort to investigate the role laminin 5 plays in the tumorigenesis of prostate carcinoma, the protein expression of the three subchains of laminin 5 (alpha 3, beta 3, and gamma 2) was compared in normal prostate, prostatic intraepithelial neoplasia, and invasive carcinoma using immunohistochemistry. The results showed that the protein for the alpha 3 subchain of laminin 5 is retained by both normal prostate epithelium and prostate carcinoma, but the beta 3 and the gamma 2 subchains were not detected in invasive carcinoma. Despite the absence of the gamma 2 protein, however, the carcinoma cells continued to express substantial amounts of the gamma 2 mRNA. Although it is unclear how the gene for the gamma 2 subchain of laminin 5 is regulated, results of this study suggest that there is a post-transcriptional defect in the expression of the gamma 2 subchain that occurs during the progression from a premalignant lesion to invasive carcinoma. As laminin 5 is a component of the anchoring filaments, the failure to express the gamma 2 subchain may contribute to the failure to form anchoring filaments and hemidesmosomes. This failure of hemidesmosome formation results in a less stable epithelial-stromal junction, which may allow malignant cells more potential to invade and spread through adjacent structures.

[Protective effects of radix Salviae miltiorrhizae on azathioprine hepatotoxicity in rats]

The changes of liver function and malondialdehyde (MDA) and glutathione (GSH) were studied in rats intoxicated with azathioprine (Aza) 15mg/(kg.d) and in rats treated with Aza mixed Salviae 8g/(kg.d). The results showed that in the Aza group, the levels of ALT, AKP, MDA increased and GSH decreased significantly in week 1 and week 2. But in the Salviae group the levels of ALT, AKP, MDA decreased and GSH increased significantly, approaching the normal levels, It follows that Salviae has protective effects on Aza hepatotoxicity in rats.

Differences in pituitary expression of proopiomelanocortin in Dahl salt-resistant and salt-sensitive rats on a high salt diet

The Dahl strain of genetically salt resistant (R) and salt sensitive (S) rats affords an opportunity to explore mechanisms for salt resistance and sensitivity. Because of the evidence that opioid peptides and their receptors can be involved in cardiovascular regulation, the objective of this study was to test the hypothesis that proopiomelanocortin (POMC), the precursor of beta-endorphin, is involved in the development of hypertension, through the determination of POMC mRNA in the pituitary. Three-week-old inbred Dahl R and S rats were maintained on a high salt diet (8% NaCl) or low salt diet (0.4% NaCl) for 6 weeks. POMC mRNA and for comparison preproenkephalin A (preproENK) mRNA were examined from tissues of Dahl R and S rats as determined by Northern blot analysis using beta-actin as an internal standard. POMC mRNA was abundant in the pituitary tissues. There was more POMC mRNA in the pituitary tissue of R rats compared with that of S rats on the high salt diet. Differences in POMC mRNA in the pituitary were not observed between R and S on the low salt diet. There were no differences in the levels of preproENK mRNA in the pituitary tissues of R and S rats on high or low salt diet. From these data, we propose that inefficient production of POMC mRNA is a characteristic of the Dahl S rat on a high salt diet.

Prevalence of hypertension and its trends in Chinese populations

The third nation-wide survey of blood pressure level and hypertension was carried out in China in 1991. In total, 950,356 residents aged > or = 15 years were examined. Sampling population were composed of half urban and half rural from 27 provinces or autonomous regions and three municipalities. The results showed that: (1) the age-adjusted prevalence rate of hypertension (systolic blood pressure > or = 140 mmHg or diastolic blood pressure > or = 90 mmHg) was 11.26% (male 12.15%, female 10.32%) and the definite hypertension rate (systolic blood pressure > or = 160 mmHg or diastolic blood pressure > or = 95 mmHg, or on medication) was 5.29% (male 5.38%, female 5.21%); rate of borderline hypertension was evaluated from 2.82% to 6.15% during the 10-year period from 1979/1980 to 1991; (2) the prevalence rate was progressively increased with age, especially after age 35; prevalence rates were generally higher in men than women before about age 44, however by age 60, women had a higher prevalence of hypertension; (3) a general trend of decrease in prevalence from north-eastern to south-western China was confirmed; (4) there were significantly lower rates in rural than in urban areas. Results of preliminary analysis for prevalence of hypertension among different occupations, nationalities, and educational levels were presented.

Hypertension prevalence and status of awareness, treatment and control in China

A nation-wide survey of blood pressure (BP) and high BP was made in China in 1991, using standardized methods and covering 950,356 men and women aged 15 years and above, from 30 provinces, autonomous regions, and municipalities. The purpose of the study was to estimate the prevalence and the status of awareness, treatment, and control of hypertension. The overall prevalence rate of hypertension defined as systolic BP > or = 140 or diastolic BP > or = 90 mmHg or currently on antihypertensive medication was 13.6%, and was higher in urban (16.3%) than in rural (11.1%) setting. The rate was 6.6% if a BP cut-point of 160/95 mmHg was used. Rates were low in younger age-groups but rose sharply after age 45. The total number of hypertensives in 1990 was estimated to be close to 90 millions. Of all hypertensives, about 1/4 were aware of their high BP, half of these were on medication, and only 3% had their BP controlled. All the rates were higher if the BP cut-point was 160/95 mmHg. Higher rates were found in urban than rural setting and, to a lesser degree, for women than men. In conclusion, hypertension was found to be common in China, and the rates of awareness, drug treatment, and controlled BP were low, indicating an urgent need for developing a national program of treatment and prevention of high BP.

Expression of hemidesmosomal and extracellular matrix proteins by normal and malignant human prostate tissue

The progression of prostate carcinoma may be influenced by the biochemical nature of the basal lamina surrounding the primary carcinoma cells. As a first step toward understanding this process, the composition and structure of the basal lamina in normal prostate, prostatic intraepithelial neoplasia, and human carcinoma were determined. In addition, a comparison was made between the attachments of the normal basal cell to its underlying basal lamina and those made by primary prostate carcinoma. The normal basal cells form both focal adhesions and hemidesmosomal-like structures as observed by transmission electron microscopy. The normal basal cells exhibited a polarized distribution of hemidesmosomal associated proteins including BP180, BP230, HD1, plectin, laminin-gamma 2(B2t), collagen VII, and the corresponding integrin laminin receptors alpha 6 beta 1 and alpha 6 beta 4. The expression and distribution pattern of these proteins were retained in the prostate intraepithelial neoplasia lesions. In contrast, the carcinoma cells uniformly lacked hemidesmosomal structures, the integrin alpha 6 beta 4, BP180, laminin-gamma 2 (B2t), and collagen VII but did express BP230 (30%), plectin, HD1 (15%), and the integrin laminin receptors alpha 3 beta 1 and alpha 6 beta 1. These results suggest that, although a detectable basal lamina structure is present in carcinoma, its composition and cellular attachments are abnormal. The loss of critical cellular attachments may play a role in influencing the progression potential of prostate carcinoma.

Electric acupuncture treatment of peripheral nerve injury

54 cases of peripheral nerve injury were treated by electric acupuncture and compared with 54 control cases treated with supportive medication. The changes after treatment were observed chiefly by electromyography while sensory and motor improvement were also recorded as auxiliary indicators. The therapeutic results in the acupuncture group were 5 cases cured, 26 markedly effective, 19 improved, and 4 cases failed, a total effective rate of 92.6% in contrast to the 55.6% for the controls. Analysis of the therapeutic results showed that 1) those in the acupuncture group were significantly better than in the control group; 2) nerve injuries should be treated as early as possible; 3) the radial nerve and the common peroneal nerve recovered faster than others; 4) cases not surgically explored recovered faster than those that were, and 5) patients with prompt propagation of the needling sensation recovered significantly faster than those with slow propagation.

Predictive control of nonlinear systems based on identification by backpropagation networks

Using the property of universal approximation of multilayer perceptron neural network, a class of discrete nonlinear dynamical systems are modeled by a perceptron with two hidden layers. A backpropagation algorithm is then used to train the model to identify the nonlinear systems to a desired level of accuracy. Based on the identified model, a one-step-ahead predictive control scheme is proposed in which the future control inputs are obtained through some nonlinear optimization process. Making use of the online learning properties of neural networks, the predictive control scheme is further developed into an adaptive one which is robust to the incompleteness of identification. Simulation results show that this neural control scheme works well even for some very complicated nonlinear systems.

A new model of neural associative memories

In this paper, we present a new model of discrete neural associative memories and its design rule. The most important feature of this new model is that a static mapping instead of the dynamic convergent process is used to retrieve the stored messages. The new model features a two-layer structure, with feedforward connections only and uses two kinds of neurons which implement different output functions. Another important feature is that this new model employs an extremely simple weight setup rule and all the resulted weights can only assume two different values, -1 and +1, which facilitates the VLSI implementation. Compared to the famous discrete Hopfield model designed with the well-known Hebbian rule or any other rule, the new model can guarantee all the given patterns to be stored as fixed points. Moreover, each fixed point is surrounded by an attraction basin (which is a ball in the Hamming distance sense) with the maximal possible radius. The performances of the new model are compared through some illustrative examples with those of the Hopfield associative memory designed using different methods.