FGF and Shh signals control dopaminergic and serotonergic cell fate in the anterior neural plate

During development, distinct classes of neurons are specified in precise locations along the dorso-ventral and anterior-posterior axes of the neural tube. We provide evidence that intersections of Shh, which is expressed along the ventral neural tube, and FGF8, which is locally produced at the mid/hindbrain boundary and in the rostral forebrain, create induction sites for dopaminergic neurons in the midbrain and forebrain. The same intersection, when preceded by a third signal, FGF4, which is expressed in the primitive streak, defines an inductive center for hindbrain 5-HT neurons. These findings illustrate that cell patterning in the neural plate is a multistep process in which early inducers, which initially divide the neural plate into crude compartments, are replaced by multiple local organizing centers, which specify distinct neuronal cell types within these compartments.

Pulsatilloside C from the roots of Pulsatilla chinensis

A new lupane-type triterpene saponin, pulsatilloside C (1), was isolated from the roots of Pulsatilla chinensis. Its structure was established to be 3beta,23-dihydroxylup-20(29)-en-28-oic acid 28-O-alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)- beta-D-glucopyranoside.

Ribosomal binding of modified tRNA anticodons related to thermal stability

The physicochemical contributions of modified nucleosides to tRNA functions are not well understood. In order to determine the contributions of specific modifications to tRNA stability as well as to ribosomal binding, ten variously modified yeast tRNA(Phe) anticodon stems and loops (tRNA(Phe)AC) were synthesized. Thermal denaturation studies on these synthetic 17mers show dramatic stabilization (or destabilization) by the presence of the various naturally occurring nucleoside modifications. Adapting a novel molecular biology approach (initially pioneered by Moazed and Noller), the interactions of these variously modified anticodons with the E. coli 16S rRNA "P-site" residues are being quantitated. The binding (affinity) constant (kD) of the tRNA(Phe)AC to the 8 of the ten 16S rRNA nucleosides that interact with tRNA and synthetic anticodons are being examined. We postulate that the "stabilizing" modifications (m1G37, psi 39, and m5C40) in the presence of an "open loop" will dramatically increase the binding affinity of the tRNA(Phe)AC to the 30S E. coli ribosomal subunit when compared to unmodified tRNA(Phe)AC. On the other hand, "destabilizing" modifications are expected to reduce the binding affinity of the tRNA(Phe)AC to the E. coli 30S ribosomal subunit. The results from these experiments have demonstrated the importance of nucleoside modifications to tRNA stability and ribosomal binding affinity, and will relate the structural contributions of nucleoside modifications to tRNA function.

[Hepatectomy for hepatolithiasis treatment of 354 cases]

OBJECTIVE

To evaluate the effect of hepatectomy for hepatolithiasis.

METHOD

354 patients with hepatolithiasis underwent hepatectomy in the past 10 years. The results were analysed retrospectively, including clinical findings, distribution of stones, patterns of operation, postoperative complications, and residual stones. The clinical data of the patients before 1990 were compared with those thereafter.

RESULT

Left hepatolithiasis was the most common form (323 patients). Left lateral lobectomy and left hepatectomy were most commonly employed (91.2%). 166 of the patients underwent concurrent cholangiojejunostomy. 13.8% patients had residual stones, and postoperative complications occurred in 60 patients, including 4 deaths. Few patients were reoperated on and the incidence of residual stones was lower after 1990. 88% the patients showed excellent or good result.

CONCLUSION

Hepatectomy is a procedure for the management of hepatolithiasis, but still requires combined plasty of stenotic intrahepatic bile ducts and cholangiojejunostomy to reduce the incidence of residual stones and recurrence.

[A case-control study on diet and gastric cancer]

OBJECTIVE

To study the relationship between consumption of fish sauce, diet, living-habit and risk of gastric cancer.

METHODS

A population-based 1:2 matched case-control study was conducted in Changle and Fuqing Cities of Fujian Province during May 1994 to July 1995. Totally, 272 matched pairs were investigated.

RESULTS

Risk state single-factor analysis indicated that there were significant associations between occurrence of gastric cancer and over consumption of fish sauce (OR = 2.57), pickled vegetables (OR = 1.41) and sea food (OR = 1.57), low consumption of fresh vegetables (OR = 1.95), citrus fruits (OR = 1.41), other fruits (OR = 1.31) and green tea (OR = 1.72), exposure to moldy cereals (OR = 2.32), taking meals at irregular times (OR = 5.47) and familial history of malignancy (OR = 3.27). No associations between risk of gastric cancer and smoking, alcohol drinking, amount of salft consumption, use of refrigerator were found. Analysis of risk state conditional logistic regression showed that fish sauce, pickled sea food, irregularly taking meals and familial history of malignancy were included in a set of risk factors for gastric cancer, with a summary attributable risk percentage of 75.49%.

CONCLUSION

Over consumption of fish sauce, pickled food, moldy cereals, irregularly taking meals and familial history of malignancy may be the local risk factors for high occurrence of gastric cancer, and fresh vegetables and fruits, green tea may have protective effects on it.

Matrix metalloproteinase inhibitors: a structure-activity study

Modifications around the dipeptide-mimetic core of a hydroxamic acid based matrix metalloproteinase inhibitor were studied. These variations incorporated a variety of natural, unnatural, and synthetic amino acids in addition to modifications of the P1' and P3' substituents. The results of this study indicate the following structural requirements: (1) Two key hydrogen bonds must be present between the enzyme and potent substrates. (2) Potent inhibitors must possess strong zinc-binding functionalities. (3) The potential importance of the hydrophobic group at position R3 as illustrated by its ability to impart greater relative potency against stromelysin when larger hydrophobic groups are used. (4) Requirements surrounding the nature of the amino acid appear to be more restrictive for stromelysin than for neutrophil collagenase, 72 kDa gelatinase, and 92 kDa gelatinase. These requirements may involve planar fused-ring aryl systems and possibly hydrogen-bonding capabilities.

[Study on GC fingerprint characteristic features of wuji baifeng pills]

In this paper, the fingerprint characteristic features that can be used for identification of Wuji Baifeng Pills were obtained by gas chromatographic analysis.

The non-uniform distribution of albumin in human and bovine cornea

In our previous studies, we noted a non-uniform distribution of protein tracer preferentially entering the anterior stromal lamellae of the cornea from the limbus. Given other differences reported previously between the anterior and posterior lamellae of the cornea, and the number of corneal disorders in which abnormalities are preferentially confined to either the anterior or posterior lamellae, we were prompted to examine the distribution of albumin in normal human and bovine cornea. The distribution of albumin in bovine and human cornea was studied immunohistochemically. Total soluble protein and albumin in the anterior 1/3 and posterior 2/3 of the central, middle and peripheral cornea of bovine eyes was measured biochemically. To aid in interpreting the findings, a theoretical model was developed based upon the combined effects of diffusive and convective transport. Using immunohistochemical methods, in both bovine and human eyes, intense staining of albumin was found in the anterior 1/3 of the corneal stroma. There was a gradual reduction in staining intensity from the limbus to the central cornea in the anterior corneal stroma. Less staining was found in the posterior 2/3 of corneal stroma. Additionally, a greater concentration of soluble protein and albumin was found in the anterior stroma than in the posterior stroma of the bovine eyes by biochemical analyses. The theoretical model demonstrated that this distribution of protein required a difference in excluded volume fraction between the anterior and posterior stroma and was consistent with a convective flux originating at the limbus and passing through the corneal stroma. The soluble proteins of the bovine and human cornea are preferentially concentrated in the anterior cornea and near the limbus. This distribution is likely due to differences in excluded volume fraction between the anterior and posterior stroma and a small convective flux passing through the cornea.

Signal model of noise in open-loop fiber-optic gyros

The characteristics of noise in fiber-optic gyros are analyzed quantitatively. Based on its physical characteristics and on autocorrelation function evidence, the noise is modeled as the addition of fractal Brownian motion (FBM) and Gaussian white noise (GWN). The value of self-similarlity parameter H in FBM and the intensity of GWN, sigma(w), in the model are robustly determined with an algorithm based on an orthonormal wavelet transform, which demonstrates well the coexistence of the long- and short-term correlation components of the gyro noise. Moreover, it is revealed that FBM dominates the gyro noise, whereas the GWN is minor.

Interendothelial junctions in normal human Schlemm's canal respond to changes in pressure

PURPOSE

To determine if changes in the structure and complexity of junctions between endothelial cells lining Schlemm's canal (SC) occur in normal human eyes with changes in perfusion pressure.

METHODS

Twelve normal human eyes were either perfusion-fixed (at 15 or 45 mm Hg) or immersion-fixed (0 mm Hg) in modified Karnovsky's fluid. 'Outflow facility was measured continually during the perfusion fixation. The intercellular junctions of the endothelial cells of SC were ultrastructurally examined in thin sections, including serial sections and freeze-fracture replicas. Morphometric data on the number of junctional strands per total length of tight junction were documented and categorized by the number of strands (one, two, or three or more). The length of endothelial cell overlap was measured on thin sections.

RESULTS

In freeze-fracture replicas, perfusion-fixed eyes demonstrated less complex junctions. At 15 mm Hg, 18.06% of the total junctional length was represented by three or more strands; at 45 mm Hg, this percentage decreased to 8.59%. In immersion-fixed eyes, 24.17% of the total junctional length was represented by three or more strands. These differences were statistically significant (P < 0.0012). In sections, the amount of endothelial cell overlap, and thus the length of paracellular pathway, was reduced in perfusion-fixed versus immersion-fixed eyes (P < 0.02). Extensive serial sectioning demonstrated that giant vacuoles were formed, either by individual endothelial cells or by two or more adjacent endothelial cells.

CONCLUSIONS

When compared with specimens fixed at zero pressure, overlap between endothelial cells of SC is reduced significantly when this cell layer is under conditions of flow similar to those encountered in vivo. The tight junctions between cells of the inner wall of SC become less complex with increasing pressure. Our data suggest that the paracellular pathway into SC in the normal eye is sensitive to modulation within a range of physiologically relevant pressures.

Thalidomide and thalidomide analogs reduce HIV type 1 replication in human macrophages in vitro

Thalidomide is currently being evaluated for efficacy in alleviating some manifestations of HIV-1 infection. To determine whether thalidomide has any direct effects on HIV-1 infection, we investigated the effect of thalidomide and also of three structural analogs of thalidomide on HIV-1 replication in vitro in human monocyte-derived macrophages. The thalidomide analogs were previously shown to inhibit TNF-alpha production in vitro at much lower concentrations than thalidomide. In HIV-1-infected macrophages treated with thalidomide or thalidomide analogs, viral replication was reduced by 60 to 80% as determined by measuring viral RT activity in the culture supernatants. In all experiments the analogs inhibited HIV-1 replication more efficiently than did thalidomide. The drugs also reduced HIV-1 gag mRNA expression. Furthermore, the drugs caused a decrease in NF-kappaB-binding activity in nuclear extracts of HIV-1-infected macrophages. The role of NF-kappaB in the drug-induced inhibition of HIV-1 replication was confirmed using an NF-kappaB-defective mutant virus to infect macrophages.

[Microbore liquid chromatography with dual electrode electrochemical detection of monoamine transmitters in brain microdialysates]

In the present work, the method of microbore liquid chromatography(MLC) with dual electrode electrochemical detection (DEED) was used to determine the monoamine transmitters and their metabolites in the striatal microdialysates from the anaesthetized rats. The potentials applied on the upstream (anodic) electrode and downstream (cathodic) electrode were set at +0.72V and +0.05V versus an Ag/AgCl reference electrode respectively. The interference of the large early-eluting peaks from brain dialysate was well eliminated on cathodic detection on the basis of electrochemical reversibility of catechol compounds. The collection efficiency of catecholamine (NA, A and DA) and DOPAC, that is the ratio of their responses in downstream electrode to those in upstream, was found to be in the range of 0.690 to 0.768, thereby providing reliable identification and measurement of early elutes. MLC-DEED is one of the best methods for the determination of monoamine transmitters at trace level. To optimize separation and detection, these adaptations were made to the system with respect to the injection valve, flow rate of the pump, connections between injector, column and detector, and cell volume of the detector. The detection limit could reach 1pg or less per injection, and the amounts, at least in the range of 2-200pg, were linearly correlated with the peak areas both at anodic detection and at cathodic detection. Prior to the collection of samples the probe recovery was measured in vitro at room temperature, and the recovery (%) for NA, DA, DOPAC, 5-HIAA, 5-HT and HVA were 19.5, 18.9, 22.1, 14,6, 16.5 and 19.3 respectively. The reported concentration of each compound was corrected according to probe recovery. The basal concentration of DA and 5-HT in striatal microdialysates was 12.5 +/- 1.8 and 5.0 +/- 0.7nmol/L. The perfussion of high K+ (100 mmol/L) through the dialysis probe induced a large increase of the concentration of NA, DA and 5-HT in microdialysates, and further increase of the concentration was observed in rat postmortem. The critical points for MLC-DEED are briefly discussed.

Hyaluronic acid in the normal and glaucomatous optic nerve

Eighteen normal human eye-bank eyes (age: 18-81 years), five fetal eyes (16-24 weeks), 11 primary open-angle glaucoma (POAG) eyes (age: 76-89 years), and two Schnabel's cavernous optic atrophy eyes were examined using a biotinylated-hyaluronan binding protein to study the changes in the distribution of hyaluronic acid (HA) in the fetal, adult and glaucomatous optic nerve head. The vitreous body served as a positive control. Sections treated with Streptomyces hyaluronidase were used to confirm specificity. Monoclonal antibodies to myelin basic protein (MBP) and glial fibrillary acidic protein (GFAP) were used as additional controls. In fetal optic nerve, HA was localized in blood vessels, peripapillary sclera and the pial septae in the retrolaminar nerve. No staining was associated with axons. Staining for MBP was negative. In adults, HA was found surrounding the myelin sheaths in the retrolaminar nerve; staining decreased with age. In contrast, HA staining in myelinated peripheral nerves (e.g. ciliaries) remained unchanged with age. HA also was localized to the adventitia of arteries and veins throughout the posterior segment. Compared to age-matched normal eyes, HA staining was virtually absent around myelin sheaths of the retrolaminar nerve in POAG eyes. Similar changes were not found in other HA positive structures. In Schnabel's cavernous optic atrophy. HA was present in increased amount in the atrophic area, but virtually absent in the remaining retrolaminar nerve. HA staining was invariably positive in vitreous, and Streptomyces hyaluronidase treated sections were negative. In adults, staining of MBP was associated with the myelin sheath in the retrolaminar nerve. In contrast to HA, staining of MBP was unchanged with age and in POAG. In Schnabel's atrophy, MBP staining disappeared only in the atrophic area. HA in the retrolaminar optic nerve appears to be associate with the space-filling matrix between myelin sheaths. HA is not present in the axon bundles prior to myelination of the optic nerve. HA in the retrolaminar optic nerve appears to decrease with age and is further reduced in POAG; however, corresponding changes are not found in MBP or in peripheral nerves. Perhaps, decreased amounts of HA is related to a higher susceptibility to elevated intraocular pressure or to optic nerve atrophy. In Schnabel's cavernous optic atrophy, HA is present in increased amount only in the atrophic area while MBP is markedly decreased, suggesting in situ production of HA in areas of optic nerve atrophy.

Percutaneous transluminal coronary angioplasty for acute myocardial infarction: initial experience in 43 cases

OBJECTIVE

To evaluate the initial experience with the use of percutaneous transluminal coronary angioplasty (PTCA) in the set of acute myocardial infarction (AMI).

METHODS

Between October 1993 and April 1996, PTCA was performed in 43 patients (34 male, 9 female) with initial onset of AMI. These patients ranged in age from 40 to 74 years (mean +/- SD, 60.3 3 +/- 9.2). Primary PTCA was performed in 16, rescue PTCA in 8, and semi-elective PTCA in 19 patients.

RESULTS

The initial success was achieved in 95.3% (41/ 43). Failed angioplasty occurred in 2 patients, with acute reocclusion after rescue PTCA (this patient died of cerebral stroke 3 days later) in one patient, and small local intimal dissection during semi-elective PTCA in another patient.

CONCLUSION

PTCA was a safe and effective approach in the treatment of AMI in the present study patients, with a high primary success and low acute complication rate.

Perforin, a cytotoxic molecule which mediates cell necrosis, is not required for the early control of mycobacterial infection in mice

Host defense against mycobacterial infection requires the participation of monocytes and T cells. Both CD4+ and CD8+ T cells have been shown to be important in resistance to mycobacterial infection in vivo. The main contribution of CD4+ T cells to the protective antituberculosis response involves the production of Th1-type cytokines, including interleukin-2 (IL-2) and gamma interferon (IFN-gamma). CD8+ T cells have been considered to be responsible primarily for cytotoxicity mediated by toxic molecules, including perforin. CD8+ T cells may also elaborate Th1-type cytokines, such as IFN-gamma, in response to the infection. To elucidate the contribution of perforin-mediated target cell death to the control of mycobacterial infection in vivo, mice with a disruption in the perforin gene (P-/-) were infected with Mycobacterium bovis BCG or M. tuberculosis Erdman for 5 and 13 weeks, respectively. At 1, 3, 5, and 13 weeks postinfection, the number of viable mycobacteria in the lungs, spleens, and livers of mice were determined by CFU assay. The infected tissues were examined histologically, and cytokine mRNA levels in the spleens of these mice were determined. Similar studies were carried out in Fas receptor-defective (CBA/lpr(cg)) mice to evaluate the contribution of this alternative cytotoxic pathway to the control of mycobacterial infection. The absence of either perforin gene function or Fas receptor gene function did not modify the course of experimental mycobacterial infection in these mice. In addition, both P-/- and Fas receptor-defective mice appeared to have a compensatory activation of cytokine genes, even in the absence of the experimental infection. P-/- mice had a mean 3.4- to 5-fold increase in mRNA levels for IL-10, IL-12p35, IL-6, and IFN-gamma. Similarly, Fas receptor-defective mice had a mean 3- to 3.6-fold increase in mRNA levels for IFN-gamma, IL-12p35, and IL-10. Our results indicate that both perforin-mediated cytotoxicity and Fas-mediated cytotoxicity do not appear to be necessary for the early control of mycobacterial infection in vivo.

The involvement of interleukin (IL)-15 in regulating the differentiation of granulated metrial gland cells in mouse pregnant uterus

Previous studies have suggested that granulated metrial gland (GMG) cells are bone marrow-derived lymphoid cells, which differentiate in situ in the mouse pregnant uterus into natural killer (NK)-like cells. Similar to NK cells, GMG cells express an abundant level of cytolytic mediators such as perforin. The factor(s) regulating the differentiation of GMG cells remain(s) to be identified, although cytokines previously implicated in the stimulation/activation of NK cells (e.g., IL-2, IL-6, IL-7, and IL-12) can be considered as potential candidates. Recently, IL-15, a novel cytokine, which displays biological activities similar to IL-2, has also been shown to be capable of activating NK cells. Using reverse transcription-polymerase chain reaction (RT-PCR) analysis, we have demonstrated in the present study that IL-15 and its cognate receptor, but not the other cytokines, are expressed in the mouse pregnant uterus, with a time course concomitant with those of cytolytic mediators in differentiated GMG cells. Moreover, IL-15, though not IL-2, is capable of inducing the expression of perforin and granzymes in pregnant uterine tissues explanted in vitro. Data obtained from in situ hybridization study have suggested that the macrophages present in the pregnant uterus may be responsible for the production of IL-15. These results suggest that IL-15 is involved in regulating the differentiation of GMG cells during mouse pregnancy.

Interleukin-15 induces the expression of mRNAs of cytolytic mediators and augments cytotoxic activities in primary murine lymphocytes

Interleukin-15 (IL-15) is a novel cytokine displaying biological activities that overlap those of interleukin-2 (IL-2). Like IL-2, IL-15 has been shown to be capable of stimulating the proliferation of human natural killer cells and PHA-treated T lymphocytes and of generating cytotoxic activity in stimulated lymphocyte populations. Using primary murine lymphocytes as a model in the present study, we have investigated the effects of IL-15 on the induction of the expression of mRNAs encoding different lymphocyte cytolytic mediators and the enhancement of cytolytic activities. Using reverse transcription-polymerase chain reaction analysis, both IL-15 and IL-2 have been shown to induce the expression of mRNAs for perforin, granzymes A and B, interferon-gamma, and Fas ligand in primary murine splenic lymphocytes. The induction effect of IL-15 has been shown to be at least partially independent of cell proliferation. Although IL-15 and IL-2 appear to be comparably effective in inducing the expression of cytolytic mediator mRNAs, the former is less potent in eliciting functional cytolytic activity in stimulated lymphocyte populations. The inadequate cytolytic activity of IL-15-stimulated lymphocytes may in part be due to the less efficient production of cytolytic mediator proteins, e.g., perforin and granzyme A, in these cells.

[Reversal of adriamycin or vincristine resistance by tetrandrine in human cancer cells in vitro]

In an in vitro culture system of human cancer cells MCF-7 and its adriamycin-resistant line MCF-7/Ad or KB and its vincristine-resistant line KBv200, tetrandrine was found to exhibit significantly selective anticancer activity against the drug-resistant cancer cell MCF-7/Ad. In addition, essentially complete reversal effects of tetrandrine on drug resistance were observed in MCF/Ad or KBv200.

[Effect of the T4 on the viscera and embryo of perinatal mice]

58 Female Kun Ming mice of perinatal stage (from the 15th day of pregnacy to the 21th day after birth) were fed with Tripcholorolide (T4) isolated from multiglycosides of Tripterygium wilfordii (GTW) at a doze of 0.6 mg/kg for group 1 or 0.3 mg/kg for group 2 per day for 4 weeks. Lactation was decreased in some females and some F1 off spring died. The succinic dehydrogenase (SDH) activity of the mice liver were increased due to the destruction of its mitocondian. Liver cells degenerated and glycogen decreased. Distal tubules of kidney degenerated. Heart and spleen were normal. T4 was also fed to 10 female mice from the 5th to 17th day of pregnacy. However, neither the absorbed fetus nor dead fetus increased.

An STS-based map of the human genome

A physical map has been constructed of the human genome containing 15,086 sequence-tagged sites (STSs), with an average spacing of 199 kilobases. The project involved assembly of a radiation hybrid map of the human genome containing 6193 loci and incorporated a genetic linkage map of the human genome containing 5264 loci. This information was combined with the results of STS-content screening of 10,850 loci against a yeast artificial chromosome library to produce an integrated map, anchored by the radiation hybrid and genetic maps. The map provides radiation hybrid coverage of 99 percent and physical coverage of 94 percent of the human genome. The map also represents an early step in an international project to generate a transcript map of the human genome, with more than 3235 expressed sequences localized. The STSs in the map provide a scaffold for initiating large-scale sequencing of the human genome.

[Protection from procarbazine induced testicular toxicity by gonadal steroid hormones]

To confirm the claims that the procarbazines (PCZ) effect on stem spermatogonia can be overcome by gonadal steroid hormones,mature,LBNF1 male rats were implanted with silastic capsules containing testosterone (T 200 mm) + estradiol (E 50 mm). The silastic capsules of control and TE groups were removed 24 hours after the PCZ injection and the rats were sacrificed 9 weeks later. The functional status of the testis and the hormonal parameters at the time of the injection of PCZ were measured and correlated with the degree of protection ,as measured by the recovery of sperm counts. The results indicated that testosterone and estradiol does protect spermatogenesis from PCZ intoxification. To determine whether the protection is specific for stem spermatogonia, we also measured body weight loss 3-4 days, lymphocyte counts 1 day, and spermatocyte count 9 days after PCZ treatment. There were no differences in the dose response curves of these three assays between the hormone and sham treated rats. The lack of protection indicates that the hormonal protection of stem spermatogonia was not due to the alterations in either systemic or testicular pharmacokinetics of spermatocyte. We conclude that A3 spermatogonia and preleptotene spermatocyte are sensitive to PCZ and there is no evidence of hormonal protection for the differentiated spermatogonia and preleptotene spermatocyte.

[Effect of Astragalus membranaceus on T-lymphocyte subsets in patients with viral myocarditis]

The efficacy of Astragalus membranaceus (AM) oral liquor combined with routine therapy and routine therapy alone on T-lymphocyte subsets of peripheral blood in viral myocarditis patients have been studied. The results showed that the T-lymphocyte subsets profile and OKT4/OKT8 ratio of peripheral blood were significantly lower in viral myocarditis patients than that in healthy control (P < 0.05, 0.01). Routine therapy combined with AM could significantly enhance OKT3, OKT4 and OKT4/OKT8 ratio in the above-mentioned patients (P < 0.05, 0.01). The possible pharmacodynamic mechanism of improved cell immunity in viral myocarditis patients by combining routine therapy with AM was discussed.