Anti-carcinogenic and anti-metastatic properties of indole-3-carbinol in prostate cancer

Indole-3-carbinol (I3C), a compound present as glucobracissin in cruciferous vegetables has anticancer activities which is in line with some of the epidemiological evidence that suggests a beneficial effect of consumption of cruciferous vegetables on cancer incidence and progression. The precise target of indole-3-carbinol has not been determined. We examined the effect of I3C on prostate cancer in a well-defined R3327 model using Copenhagen rats and the transplantable cell line, MAT-LyLu. This cell line derived from a tumor in Copenhagen rats is androgen independent and metastasizes to the lung and lymph nodes. Tumors were induced in Copenhagen rats by injecting MAT-LyLu subcutaneously and the animals treated with I3C that was administered either intraperitoneally or intravenously, in order to achieve maximal systemic exposure. This was a departure from the traditional chemopreventive route of indole-3-carbinol where the compound was incorporated in the diet. Our results indicate that I3C inhibited the incidence, growth and metastases of MAT-LyLu cells and both i.p. and i.v. injections of I3C were equally effective. Statistical analysis (Kaplan-Meier curves) clearly indicates a tumor-free and overall survival benefit as a result of treatment with I3C. These studies show for the first time that I3C in an injectible form has anti-prostate cancer activity.

Peptide mimotopes of oncoproteins as therapeutic agents in breast cancer

Generation of an immune response to oncoproteins can lead to a cancer specific protective immunity. Several such oncoproteins are being examined as tumor targets with mixed results. We are evaluating the clinical utility of synthetic peptides that would mimic the antigen immunologically and elicit a tumor specific immune response. HER-2/neu, an oncoprotein whose expression in breast cancer is associated with poor prognosis, lower disease free-survival and a propensity for metastases was chosen as a model. Antibodies, Ab2, Ab4 and Ab5 directed towards the extracellular domain of HER-2/neu were reacted to peptides from two synthetic phage display peptide libraries, LX-8 (12-mer peptide library containing disulfide bridge) and X-15 (linear 15-mer). The isolated peptides were sequenced and characterized for ability to produce high titer antibodies and cross-reactivity. The peptides isolated did not show any sequence homology to protein databases but did show a hierarchy of immunogenic epitopes. Antibodies generated against peptides selected against the same antibody Ab2 or Ab4 showed affinity variation. Phages selected against Ab2 were also able to compete with binding of Ab2 to HER-2/neu. These results validate our hypothesis that synthetic peptides that mimic the antigenic epitope of oncoprotein can be generated and their clinical utility rests on devising a screening mechanism to identify peptides that can elicit an immune response directed to the oncoprotein and if possible its antigenic variants.

Induction of heat shock protein gp96 by immune cytokines

Cytokines play a major role in regulating both humoral and cell-mediated immune responses. Recent advances in our understanding of cell-mediated immune responses have focused on the antigen presentation machinery and the proteins in the endoplasmic reticulum (ER). These proteins help the formation and stabilization of the major histocompatibility complex (MHC)-peptide interaction. A 96-kDa, ER-resident glycoprotein (gp96) is being evaluated as a therapeutic agent in cancer because of its ability to associate with a vast number of cellular peptides irrespective of size or sequence. Because the antigen presentation complex is assembled in the ER and a number of ER-resident proteins are modulated by cytokines, it is important to examine the regulation of gp96 in response to immune cytokines interferon gamma (IFN-gamma), and interleukin 2 (IL-2). Defects in signaling pathway in either of the cytokines can result in suboptimal immune response. We examined the effect of the cytokines IFN-gamma and IL-2 on the induction of gp96 in different cancer cell lines and examined the induction of DNA-binding proteins that recognize gamma interferon-activating sequence (GAS), present in the promoter region of gp96. The induction of GAS binding protein correlated with the induction of STAT 1 protein, a transcriptional regulator and mediator of IFN-gamma-mediated gene expression. The use of cytokines in inducing gp96 levels may have significance in maintaining high levels of gp96 for a sustained immune response.

Multiple molecular targets of indole-3-carbinol, a chemopreventive anti-estrogen in breast cancer

The mechanism of action of the anti-estrogen indole-3-carbinol (I3C), present in cruciferous vegetables, is being examined in our laboratory with a view to promote the use of this naturally occurring chemopreventive as an alternative to synthetic anti-estrogens in human breast cancer. Our previous results clearly demonstrated that despite its low affinity for the estrogen receptor (ER), I3C abrogated estradiol-mediated cellular and biochemical effects in estradiol-responsive cells and tissues. In an earlier report, we identified ER phosphorylation as one of the targets of I3C, and in this communication we describe the consequence of inhibition of ER phosphorylation. Estradiol-induced DNA-binding proteins that bound to several DNA-responsive elements were inhibited by I3C and this effect was not at the level of DNA-protein physical interaction as inclusion of I3C in vitro in the reaction mix did not affect the binding. We analyzed the spectrum of genes induced by estradiol and modulated and/or intercepted by I3C. Our results conclude that although estradiol-mediated functions are affected by I3C, its biochemical targets are multiple and some of these may be modulated by the oligomeric products of I3C.

Compounds from Kadsura ananosma

The 18-(13-->12 beta)-abeo-lanostene triterpenoid acid, ananosic acid A (1), and the dibenzocyclooctadiene lignan, ananosin A (2), were isolated from the stem bark of Kadsura ananosma. Their structures were elucidated by extensive spectral studies and the structure of 1 was confirmed by single crystal X-ray diffraction analysis.

[New progress of serial analysis of gene expression]

As an efficient tool that has been developed recently, serial analysis of gene expression (SAGE) allows the qualitative and quantitative analysis of a large number of transcripts. It can define the transcripts at relatively low levels and characterize the genomic expression near completion. In addition, it provides insights into the timely and orderly expression of genes by comparing the profiles constructed for a pair of cells that are kept at different conditions, thus identifying a set of novel genes. In this review, the newest progress of SAGE's application and research is mentioned in details with its original method and principle outlined.

[Studies on chemical constituents of Schisandra propinqua (Wall.) Hook. f. et Thoms]

OBJECTIVE

To isolate and characterize compounds from the stems of Schisandra propinqua.

METHOD

Extracting with solvent, isolating by column chromatography and identifying by the spectroscopic methods.

RESULT

Six dibenzocyclooctadiene lignans were isolated and identified as tigloylgomisin P(1), angeloylgomisin O(2), angeloylisogomisin O(3), kadsulignan L(4), (+/-) 5,8-epoxyl-6, 7-dimethyl-2',3',2",3"-dimethylenedioxy-4', 1"-dimethyl-1,2:3,4-dibenzo-1, 3-cyclooctadiene(5) and wuweizisu C(6).

CONCLUSION

Compounds 4 and 5 were the first two dibenzocyclooctadiene lignans with an 6,9-epoxy bridge cycle discovered in the genus Schisandra. The others were originally isolated from S. propinqua.

The TGF beta receptor activation process: an inhibitor- to substrate-binding switch

The type I TGF beta receptor (T beta R-I) is activated by phosphorylation of the GS region, a conserved juxtamembrane segment located just N-terminal to the kinase domain. We have studied the molecular mechanism of receptor activation using a homogeneously tetraphosphorylated form of T beta R-I, prepared using protein semisynthesis. Phosphorylation of the GS region dramatically enhances the specificity of T beta R-I for the critical C-terminal serines of Smad2. In addition, tetraphosphorylated T beta R-I is bound specifically by Smad2 in a phosphorylation-dependent manner and is no longer recognized by the inhibitory protein FKBP12. Thus, phosphorylation activates T beta R-I by switching the GS region from a binding site for an inhibitor into a binding surface for substrate. Our observations suggest that phosphoserine/phosphothreonine-dependent localization is a key feature of the T beta R-I/Smad activation process.

[Studies on chemical constituents of Stellera chamejasma L]

OBJECTIVE

Isolate and identify the bioactive compounds from the root of Stellera chamejasma.

METHOD

The compounds were extracted with solvents, isolated by column chromatography and identified by spectroscopic methods.

RESULT

Seven compounds were isolated and identified as umbelliferone(1); daphnoretin (2); 2,6-dimethoxyl p-benzoquinone(3); (-)-eudesmin(4); (+)-matairesinol(5); lirioresinol B(6) and daucosterol(7).

CONCLUSION

Compounds 3, 4 and 5 were isolated from the plant for the first time.

Triterpenoid acids from Schisandra propinqua with cytotoxic effect on rat luteal cells and human decidual cells in vitro

Three triterpenoid acids, nigranoic acid (1), manwuweizic acid (2), schisandronic acid (3), and other four compounds were isolated from the stems of Schisandra propinqua. Compounds 1 and 2 showed significant cytotoxic effect against human decidual cells and rat luteal cells in vitro.

A cDNA from human bone marrow encoding a protein exhibiting homology to the ATP1gamma1/PLM/MAT8 family of transmembrane proteins

A cDNA clone, IWU-1, was cloned from human bone marrow. Its putative open reading frame encoded a protein of 115 amino acids with a calculated molecular mass of 12.9 kDa. The deduced amino acid sequence exhibited high homology (>68%) to members of the ATP1gamma1/PLM/MAT8 family of single transmembrane proteins, primarily in the region containing the putative transmembrane domain. The sequence at the amino-terminal side exhibited high homology (>61%) to the cytoplasmic region of the angiotensin II type 1 receptors.

Effects of pathway and neuronal aging on the specificity of motor axon regeneration

Youth is a strong predictor of functional recovery after peripheral nerve repair, while adulthood is commonly associated with poor outcome. Identification of the factors responsible for this difference could form the basis for strategies to improve regeneration in adults. Preferential reinnervation of motor pathways by motor axons (PMR) occurs strongly in young rats, but is often absent in older animals, and thus parallels the overall trend for superior results in young individuals. These experiments evaluate the individual contributions of peripheral nerve age and motoneuron age to the decline in regeneration specificity (PMR) which accompanies the aging process. The femoral nerves of young and old Lewis rats were removed as inverted "Y" grafts from the femoral trunk proximally to the terminal muscle and cutaneous branches distally. These grafts were transferred from (1) old to young, (2) young to old, (3) old to old, and (4) young to young bilaterally in 10 individuals per group. After 8 weeks of regeneration, reinnervation of cutaneous and muscle branches was assessed by dual labeling with HRP and Fluoro-Gold. Motor neuron regeneration was random in old to old (mean muscle branch (M) = 159, mean cutaneous branch (C) = 168), but PMR was seen when young pathways were used in old animals (M = 163, C = 116). PMR was vigorous when either type of graft was used in young animals (young graft, M = 218, C = 134; old graft, M = 204, C = 127). In this model, motoneuron age appears to be the primary determinant of specificity. However, the pathway also makes significant contributions, as shown by the ability of young pathways to generate specificity in old animals. Manipulation of graft Schwann cell behavior might therefore be an appropriate strategy to improve outcome in older individuals.

Expression of mPer1 and mPer2, two mammalian clock genes, in murine bone marrow

Although circadian variations in hematopoiesis have been well documented, the molecular mechanism of the circadian rhythms remains elusive. To determine if a clock system exists in bone marrow to mediate the circadian rhythms, we analyzed the expression of mPer1 and mPer2, both mouse homologues of the Drosophila period gene and known regulators of the clock system, in murine bone marrow by relative quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). We demonstrated that both genes were expressed in bone marrow. Furthermore, the expression patterns of mPer1 and mPer2 in total bone marrow cells exhibited two peaks over a 24-h period. In contrast, the expression patterns of these two genes in the Gr-1-positive cells isolated from bone marrow mainly contributed to one of the two peaks. These results indicate that a clock system exists in bone marrow and suggest that the circadian rhythms in bone marrow are lineage- and/or differentiation stage-dependent.

Engagement of bone morphogenetic protein type IB receptor and Smad1 signaling by anti-Müllerian hormone and its type II receptor

Anti-Müllerian hormone induces the regression of fetal Müllerian ducts and inhibits the transcription of gonadal steroidogenic enzymes. It belongs to the transforming growth factor-beta family whose members signal through a pair of serine/threonine kinase receptors and Smad effectors. Only the anti-Müllerian hormone type II receptor has been identified. Our goal was to determine whether anti-Müllerian hormone could share a type I receptor with another family member. Co-immunoprecipitation of known type I receptors with anti-Müllerian hormone type II receptor clearly showed that the bone morphogenetic protein type IB receptor was the only cloned type I receptor interacting in a ligand-dependent manner with this type II receptor. Anti-Müllerian hormone also activates the bone morphogenetic protein-specific Smad1 pathway and the XVent2 reporter gene, an anti-Müllerian hormone type II receptor-dependent effect abrogated by a dominant negative version of bone morphogenetic protein type IB receptor. Reverse amplification experiments showed that bone morphogenetic protein type IB receptor is co-expressed with anti-Müllerian hormone type II receptor in most anti-Müllerian hormone target tissues. Our data support a model in which a ligand, anti-Müllerian hormone, gains access to a shared type I receptor and Smad1 system through a highly restricted type II receptor.

Preparation of Der p 1 specific monoclonal antibodies and use in a two-site-ELISA to detect Der p 1 allergen

It has been well documented that the mite Dermatophoides pteronyssinus (Der p) is the major allergen in house dust in Taiwan. The purpose of this study is to develop a sandwich immunometric assay which can be used for the standardization of mite allergen extracts or house dust, for assessing the procedures of mite avoidance, and for identifying species in epidemiological studies. Der p 1 allergen (both recombinant and native Der p 1) was purified and a panel of Der p 1 specific monoclonal antibodies was developed. The monoclonal antibodies were biotinylated and a two-site enzyme-linked immunosorbent assay (ELISA) with peroxidase-conjugated streptavidin was developed for the detection of Der p 1 allergen. The results suggest that these monoclonal antibodies could be applied both in affinity columns for the purification of native Der p 1 antigen and in sandwich-ELISA for epidemiological study.

A new trinortriterpenoid from Cleome chrysantha

A new trinortriterpenoid, 1-epibrachyacarpone, was isolated from aerial parts of Cleome chrysantha. Its structure was elucidated as 1 by NMR investigations and X-ray crystallographic studies.

Structural basis of Smad2 recognition by the Smad anchor for receptor activation

The Smad proteins mediate transforming growth factor-beta (TGFbeta) signaling from the transmembrane serine-threonine receptor kinases to the nucleus. The Smad anchor for receptor activation (SARA) recruits Smad2 to the TGFbeta receptors for phosphorylation. The crystal structure of a Smad2 MH2 domain in complex with the Smad-binding domain (SBD) of SARA has been determined at 2.2 angstrom resolution. SARA SBD, in an extended conformation comprising a rigid coil, an alpha helix, and a beta strand, interacts with the beta sheet and the three-helix bundle of Smad2. Recognition between the SARA rigid coil and the Smad2 beta sheet is essential for specificity, whereas interactions between the SARA beta strand and the Smad2 three-helix bundle contribute significantly to binding affinity. Comparison of the structures between Smad2 and a comediator Smad suggests a model for how receptor-regulated Smads are recognized by the type I receptors.

Innervation of the metacarpophalangeal and interphalangeal joints: a microanatomic and histologic study of the nerve endings

Six pairs of fresh human cadaver hands were dissected under the surgical microscope at x28 to x32 and selectively silver stained. In addition, 18 proximal interphalangeal and metacarpophalangeal joints of fresh cadaver hands were processed with protein gene product 9.5 for measurement and analysis of nerve endings in those joints. The results demonstrated that the proximal interphalangeal joints are innervated by 2 palmar articular nerves (mean diameter, 0.21-0.53 mm). Each metacarpophalangeal joint of the second through fifth fingers is predominantly supplied by 1 palmar articular nerve (mean diameter, 0.41-0.59 mm), which comes from the deep branches of the ulnar nerve, as well as by 2 dorsal articular nerves (mean diameter, 0.11-0.24 mm). The metacarpophalangeal joint of the thumb also had 2 dorsal articular nerves (mean diameter, 0.18-0.24 mm) and 2 palmar joint nerves (mean diameter, 0.29-0.31 mm). The mean densities of the type IV free nerve endings and the mean numbers of the encapsulated endings in the palmar capsules were consistently much greater than in the dorsal or lateral capsules. The majority of encapsulated endings were pacinian corpuscles. The anatomic and histologic information may help the surgeon avoid damaging these small joint nerves during operative procedures and to reconstruct or de-innervate them if necessary. (J Hand Surg 2000; 25A:128-133.

[Studies on fermentation conditions for the accumulation of poly-beta-hydroxybutyrate in Alcaligenes eutrophus]

The results of the cultivation of Alcaligenes eutrophus showed that nitrogen limitation or exhaustion could stimulate the substantial accumulation of PHB. But the exhaustion of nitrogen source in PHB formation period would result in the rapid drop of PHB synthetic rate. Oxygen limitation could also stimulate the formation of PHB, but the content of PHB in the cell was much less than that in case of nitrogen controlled conditions. Obvious influences were observed on PHB fermentation when ammonia water feeding was stopped at different cell growth phases, and better results could be obtained when it was performed at 20 g/L to 30 g/L of residual biomass. Cell dry weight, PHB content and PHB concentration reached 61.9 g/L, 80.5% and 49.0 g/L, respectively under desired conditions.

TbetaR-I(6A) is a candidate tumor susceptibility allele

We have previously described a type I transforming growth factor (TGF)-beta receptor (TbetaR-I) polymorphic allele, TbetaR-I(6A), that has a deletion of three alanines from a nine-alanine stretch. We observed a higher than expected number of TbetaR-I(6A) homozygotes among tumor and nontumor DNA from patients with a diagnosis of cancer. To test the hypothesis that TbetaR-I(6A) homozygosity is associated with cancer, we performed a case-control study in patients with a diagnosis of cancer and matched healthy individuals with no history of cancer and who were identical in their gender and their geographical and ethnic background to determine the relative germ-line frequencies of this allele. We found nine TbetaR-I(6A) homozygotes among 851 patients with cancer. In comparison, there were no TbetaR-I(6A) homozygotes among 735 healthy volunteers (P < 0.01). We also observed an excess of TbetaR-I(6A) heterozygotes in cancer cases compared to controls (14.6% versus 10.6%; P = 0.02, Fisher's exact test). A subset analysis revealed that 4 of 112 patients with colorectal cancer were TbetaR-I(6A) homozygotes (P < 0.01). Using mink lung epithelial cell lines devoid of TbetaR-I, we established stably transfected TbetaR-I and TbetaR-I(6A) cell lines. We found that, compared to TbetaR-I, TbetaR-I(6A) was impaired as a mediator of TGF-beta antiproliferative signals. We conclude that TbetaR-I(6A) acts as a tumor susceptibility allele that may contribute to the development of cancer, especially colon cancer, by means of reduced TGF-beta-mediated growth inhibition.

Silencing of TGF-beta signalling by the pseudoreceptor BAMBI

Members of the transforming growth factor-beta (TGF-beta) superfamily, including TGF-beta, bone morphogenetic proteins (BMPs), activins and nodals, are vital for regulating growth and differentiation. These growth factors transduce their signals through pairs of transmembrane type I and type II receptor kinases. Here, we have cloned a transmembrane protein, BAMBI, which is related to TGF-beta-family type I receptors but lacks an intracellular kinase domain. We show that BAMBI is co-expressed with the ventralizing morphogen BMP4 (refs 5, 6) during Xenopus embryogenesis and that it requires BMP signalling for its expression. The protein stably associates with TGF-beta-family receptors and inhibits BMP and activin as well as TGF-beta signalling. Finally, we provide evidence that BAMBI's inhibitory effects are mediated by its intracellular domain, which resembles the homodimerization interface of a type I receptor and prevents the formation of receptor complexes. The results indicate that BAMBI negatively regulates TGF-beta-family signalling by a regulatory mechanism involving the interaction of signalling receptors with a pseudoreceptor.

Characterization of monoclonal antibodies against hepatitis C virus nonstructural protein 3: different antigenic determinants from human B cells

The nonstructural (NS3) region protein of hepatitis C virus (HCV) possesses major B-cell epitopes that induce antibodies after infection. To elucidate further the characteristics of these B cells and their role in the immune regulation of HCV infection, T9 (portion of NS3 region, amino acids [a.a.] 1188-1493)-specific monoclonal antibodies were derived and mapped for B-cell antigenic determinants with recombinant proteins. A total of 10 T9-specific hybridomas were generated and tested for B-cell antigenic determinants. To analyze the B-cell antigenic determinants, eight recombinant proteins including NS3-e (a.a. 1175-1334), NS3-a' (a.a. 1175-1250), NS3-a (a.a. 1251-1334), NS3-b (a.a. 1323-1412), NS3-c (a.a. 1407-1499), NS3-a/b (a.a. 1251-1412), NS3-bc (a.a. 1323-1499), and NS3-abc (a.a. 1251-1499) encoded by NS3-region internal clones were expressed and tested for immunoblotting. The data suggested IgG hybridomas recognized NS3-a, NS3-a', or NS3-b protein by immunoblotting. By contrast, the NS3-e protein bears the major antigenic determinant recognized by human sera. Half of the hybridomas were found to react with protein NS3-a', which is not a major B-cell antigenic determinant in humans. These data suggested that conformational epitopes in vivo may be important for B-cell recognition.

Smad1 recognition and activation by the ALK1 group of transforming growth factor-beta family receptors

Two structural elements, the L45 loop on the kinase domain of the transforming growth factor-beta (TGF-beta) family type I receptors and the L3 loop on the MH2 domain of Smad proteins, determine the specificity of the interactions between these receptors and Smad proteins. The L45 sequence of the TGF-beta type I receptor (TbetaR-I) specifies Smad2 interaction, whereas the related L45 sequence of the bone morphogenetic protein (BMP) type I receptor (BMPR-I) specifies Smad1 interactions. Here we report that members of a third receptor group, which includes ALK1 and ALK2 from vertebrates and Saxophone from Drosophila, specifically phosphorylate and activate Smad1 even though the L45 sequence of this group is very divergent from that of BMPR-I. We investigated the structural elements that determine the specific recognition of Smad1 by ALK1 and ALK2. In addition to the receptor L45 loop and the Smad1 L3 loop, the specificity of this recognition requires the alpha-helix 1 of Smad1. The alpha-helix 1 is a conserved structural element located in the vicinity of the L3 loop on the surface of the Smad MH2 domain. Thus, Smad1 recognizes two distinct groups of receptors, the BMPR-I group and the ALK1 group, through different L45 sequences on the receptor kinase domain and a differential use of two surface structures on the Smad1 MH2 domain.

Crystal structure of the cytoplasmic domain of the type I TGF beta receptor in complex with FKBP12

Activation of the type I TGFbeta receptor (TbetaR-I) requires phosphorylation of a regulatory segment known as the GS region, located upstream of the serine/threonine kinase domain in the cytoplasmic portion of the receptor. The crystal structure of a fragment of unphosphorylated TbetaR-I, containing both the GS region and the catalytic domain, has been determined in complex with the FK506-binding protein FKBP12. TbetaR-I adopts an inactive conformation that is maintained by the unphosphorylated GS region. FKBP12 binds to the GS region of the receptor, capping the TbetaR-II phosphorylation sites and further stabilizing the inactive conformation of TbetaR-I. Certain structural features at the catalytic center of TbetaR-I are characteristic of tyrosine kinases rather than Ser/Thr kinases.

Contributions of pathway and neuron to preferential motor reinnervation

Motor axons regenerating after transection of mixed nerve preferentially reinnervate distal muscle branches, a process termed preferential motor reinnervation (PMR). Motor axon collaterals appear to enter both cutaneous and muscle Schwann cell tubes on a random basis. Double-labeling studies suggest that PMR is generated by pruning collaterals from cutaneous pathways while maintaining those in motor pathways (the "pruning hypothesis"). If all collaterals projecting to muscle are saved, then stimulation of regenerative sprouting should increase specificity by increasing the number of motoneurons with at least one collateral in a muscle pathway. In the current experiments, collateral sprouting is stimulated by crushing the nerve proximal to the repair site before suture, a maneuver that also conditions the neuron and predegenerates the distal pathway. Control experiments are performed to separate these effects from those of collateral generation. Experiments were performed on the rat femoral nerve and evaluated by exposing its terminal cutaneous and muscle branches to HRP or Fluoro-Gold. Crush proximal to the repair site increased motor axon collaterals at least fivefold and significantly increased the percentage of correctly projecting motoneurons, consistent with the pruning hypothesis. Conditioning the nerve with distal crushes before repair had no effect on specificity. A graft model was used to separate the effects of collateral generation and distal stump predegeneration. Previous crush of the proximal femoral nerve significantly increased the specificity of fresh graft reinnervation. Stimulation of regenerative collateral sprouting thus increased PMR, confirming the pruning hypothesis. However, this effect was overshadowed by the dramatic specificity with which predegenerated grafts were reinnervated by fresh uncrushed proximal axons. These unexpected effects of predegeneration on specificity could involve a variety of possible mechanisms and warrant further study because of their mechanistic and clinical implications.

The effect of denervated muscle and Schwann cells on axon collateral sprouting

The effects of denervated muscle and Schwann cells on collateral sprouting from peripheral nerve were studied in the peroneal and tibial nerves of 48 Sprague-Dawley rats. Three groups were prepared. In group MSW (muscle-Schwann cell-window), the peroneal nerves were transected 3 mm below the sciatic bifurcation. The proximal stumps were sealed in a blocked tube to prevent regeneration and the distal stumps were implanted into denervated muscle cells that were wrapped around the ipsilateral tibial nerve, which had a window of perineurium resected. Schwann cells from the ipsilateral sural nerve were implanted into the muscle. Group MS (muscle-Schwann cell) was similar to group MSW, except that the tibial nerve perineurium was kept intact. In group MW (muscle-window), the muscle was prepared without Schwann cells and the tibial nerve perineurium was windowed. S-100 immunostain was used to identify the Schwann cells surviving 1 week after transplantation. After 16 weeks of regeneration, horseradish peroxidase tracer was used to label motor neurons and sensory neurons reinnervating the peroneal nerve. Myelinated axons of the reinnervated peroneal nerves were quantified with the Bioquant OS/2 computer system (R&M Biometrics, Nashville, TN). A mean of 169 motor neurons in group MSW, 64 in group MW, and 26 in group MS reinnervated the peroneal nerve. In the dorsal root ganglion, the mean number of labeled sensory neurons was 1,283 in group MSW, 947 in group MS, and 615 in group MW. The mean number of myelinated axons in the reinnervated peroneal nerve was 1,659 in group MSW, 359 in group MS, and 348 in group MW. Reinnervated anterolateral compartment muscles in group MSW were significantly heavier than those in group MS or MW. This study demonstrates that the transplantation of denervated muscle and Schwann cells promotes motor and sensory nerve collateral sprouting through a perineurial window.

Determinants of specificity in TGF-beta signal transduction

Signal transduction by the TGF-beta family involves sets of receptor serine/threonine kinases, Smad proteins that act as receptor substrates, and Smad-associated transcription factors that target specific genes. We have identified discrete structural elements that dictate the selective interactions between receptors and Smads and between Smads and transcription factors in the TGF-beta and BMP pathways. A cluster of four residues in the L45 loop of the type I receptor kinase domain, and a matching set of two residues in the L3 loop of the Smad carboxy-terminal domain establish the specificity of receptor-Smad interactions. A cluster of residues in the highly exposed alpha-helix 2 of the Smad carboxy-terminal domain specify the interaction with the DNA-binding factor Fast1 and, as a result, the gene responses mediated by the pathway. By establishing specific interactions, these determinants keep the TGF-beta and BMP pathways segregated from each other.

Microarterial anatomy of the lesser toe proximal interphalangeal joints

Successful free tissue transfer requires detailed knowledge of the pertinent microvascular anatomy of the donor site. The lesser toe proximal interphalangeal joints are a source of vascularized autologous tissue. In 20 adult cadaver feet, the arterial anatomy of the second, third, and fourth toes was studied using colored latex and India ink injection. The second, third, and fourth dorsal metatarsal arteries produced small or absent dorsal digital arteries in 72.5% of distal dissections. The proper digital arteries were 0.93 to 1.37 cm in length. An additional 2.3 to 2.83 cm of length can be gained by use of the plantar metatarsal arteries if the dorsal metatarsal or dorsal digital arteries are inadequate. The diameter of the medial proper digital arteries (range, 1.2-1.26 mm) was larger than the lateral proper digital arteries (range, 0.66-0.99 mm). The proper digital arteries of the lesser toes provide the predominant arterial supply of the proximal interphalangeal joints through a system of transverse and longitudinal arches.

The L3 loop: a structural motif determining specific interactions between SMAD proteins and TGF-beta receptors

Signal transduction specificity in the transforming growth factor-beta (TGF-beta) system is determined by ligand activation of a receptor complex which then recruits and phosphorylates a subset of SMAD proteins including Smads 1 and 2. These then associate with Smad4 and move into the nucleus where they regulate transcription. We have identified a discrete surface structure in Smads 1 and 2 that mediates and specifies their receptor interactions. This structure is the L3 loop, a 17 amino acid region that protrudes from the core of the conserved SMAD C-terminal domain. The L3 loop sequence is invariant among TGF-beta- and bone morphogenetic protein (BMP)-activated SMADS, but differs at two positions between these two groups. Swapping these two amino acids in Smads 1 and 2 induces a gain or loss, respectively, in their ability to associate with the TGF-beta receptor complex and causes a switch in the phosphorylation of Smads 1 and 2 by the BMP and TGF-beta receptors, respectively. A full switch in phosphorylation and activation of Smads 1 and 2 is obtained by swapping both these two amino acids and four amino acids near the C-terminal receptor phosphorylation sites. These studies identify the L3 loop as a determinant of specific SMAD-receptor interactions, and indicate that the L3 loop, together with the C-terminal tail, specifies SMAD activation.

Lignans from Kadsura angustifolia

A new dibenzocyclooctadiene lignan named angustifolin D (1) together with four known lignans: kadsulignan L (2), kadsulignan N (3), schisantherin P (4) and meso-dihydroguaiaretic acid (5) were isolated from the stems of Kadsura angustifolia. Their structures and stereochemistries were elucidated by spectral studies. Compounds 2 and 5 showed moderate platelet-activating factor (PAF) antagonistic activities with IC50 values of 2.6 x 10(-5) and 4.1 x 10(-5) M, respectively.

Phospholipase D stimulates release of nascent secretory vesicles from the trans-Golgi network

Phospholipase D (PLD) is a phospholipid hydrolyzing enzyme whose activation has been implicated in mediating signal transduction pathways, cell growth, and membrane trafficking in mammalian cells. Several laboratories have demonstrated that small GTP-binding proteins including ADP-ribosylation factor (ARF) can stimulate PLD activity in vitro and an ARF-activated PLD activity has been found in Golgi membranes. Since ARF-1 has also been shown to enhance release of nascent secretory vesicles from the TGN of endocrine cells, we hypothesized that this reaction occurred via PLD activation. Using a permeabilized cell system derived from growth hormone and prolactin-secreting pituitary GH3 cells, we demonstrate that immunoaffinity-purified human PLD1 stimulated nascent secretory vesicle budding from the TGN approximately twofold. In contrast, a similarly purified but enzymatically inactive mutant form of PLD1, designated Lys898Arg, had no effect on vesicle budding when added to the permeabilized cells. The release of nascent secretory vesicles from the TGN was sensitive to 1% 1-butanol, a concentration that inhibited PLD-catalyzed formation of phosphatidic acid. Furthermore, ARF-1 stimulated endogenous PLD activity in Golgi membranes approximately threefold and this activation correlated with its enhancement of vesicle budding. Our results suggest that ARF regulation of PLD activity plays an important role in the release of nascent secretory vesicles from the TGN.

Mechanism of TGFbeta receptor inhibition by FKBP12

Transforming growth factor-beta (TGFbeta) signaling requires phosphorylation of the type I receptor TbetaR-I by TbetaR-II. Although TGFbeta promotes the association of TbetaR-I with TbetaR-II, these receptor components have affinity for each other which can lead to their ligand-independent activation. The immunophilin FKBP12 binds to TbetaR-I and inhibits its signaling function. We investigated the mechanism and functional significance of this effect. FKBP12 binding to TbetaR-I involves the rapamycin/Leu-Pro binding pocket of FKBP12 and a Leu-Pro sequence located next to the activating phosphorylation sites in TbetaR-I. Mutations in the binding sites of FKBP12 or TbetaR-I abolish the interaction between these proteins, leading to receptor activation in the absence of added ligand. FKBP12 does not inhibit TbetaR-I association with TbetaR-II, but inhibits TbetaR-I phosphorylation by TbetaR-II. Rapamycin, which blocks FKBP12 binding to TbetaR-I, reverses the inhibitory effect of FKBP12 on TbetaR-I phosphorylation. By impeding the activation of TGFbeta receptor complexes formed in the absence of ligand, FKBP12 may provide a safeguard against leaky signaling resulting from the innate tendency of TbetaR-I and TbetaR-II to interact with each other.

ADP-ribosylation factor-1 stimulates formation of nascent secretory vesicles from the trans-Golgi network of endocrine cells

ADP-ribosylation factor (ARF) is a small GTP-binding protein that has been implicated in intracellular vesicular transport. ARF regulates the budding of vesicles that mediate endoplasmic reticulum to Golgi and intra-Golgi transport. It also plays an important role in maintaining the function and morphology of the Golgi apparatus. Using a permeabilized cell system derived from GH3 cells, we provide evidence that ARF-1 regulates the formation of nascent secretory vesicles from the trans-Golgi network. Both myristoylated and non-myristoylated forms of recombinant human ARF-1 enhanced secretory vesicle budding about 2-fold. A mutant lacking the first 17 N-terminal residues, as well as one that preferentially binds GDP (T31N) did not stimulate vesicle formation. In contrast, a mutant defective in GTP hydrolysis (Q71L) promoted vesicle budding. Strikingly, a peptide corresponding to the N terminus of human ARF-1 (amino acids 2-17) also stimulated vesicle budding from the trans-Golgi network, in marked contrast to its inhibitory effect on vesicular transport from the endoplasmic reticulum to Golgi. These data demonstrate that in endocrine cells, ARF-1 and in particular its N terminus play an essential role in the formation of secretory vesicles.

The propeptide of anglerfish preprosomatostatin-I rescues prosomatostatin-II from intracellular degradation

Polypeptide hormones and neuropeptides are initially synthesized as precursors possessing one or several domains that constitute the propeptide. Previous work from our laboratory demonstrated that expression of anglerfish prosomatostatin-I (proSRIF-I) in rat anterior pituitary GH3 cells resulted in efficient and accurate cleavage of the prohormone to generate the mature 14-amino acid peptide, SRIF-I. We also implicated the propeptide in mediating intracellular sorting to the trans Golgi network where proteolytic processing is initiated. In contrast, expression of a second form of the precursor, proSRIF-II in GH3 cells resulted in its intracellular degradation in an acidic, post-trans Golgi network compartment, most probably lysosomes. To further investigate the positive sorting signal present in proSRIF-I, we constructed a chimera comprising the signal peptide and proregion of SRIF-I fused to proSRIF-II and expressed the cDNA in GH3 cells. Here we demonstrate that the propeptide of SRIF-I rescued proSRIF-II from intracellular degradation quantitatively and diverted it to secretory vesicles. Furthermore, the chimera was processed to SRIF-28, an amino-terminally extended form of the hormone that is the physiological cleavage product of proSRIF-II processing in vivo. Most significantly, the SRIF-I propeptide functioned only in cis as part of the fusion protein and not in trans when expressed as a separate polypeptide. These data suggest that the SRIF-I propeptide may possess a sorting signal for sequestration into the secretory pathway rather than functioning as an intramolecular chaperone to promote protein folding.

Application of dot-immunogold-silver staining in the diagnosis of clonorchiasis

All 35 confirmed clonorchiasis cases showed a positive reaction in dot-immunogold-silver staining (Dot-IGSS) with a mean serum titre of 1:1656, while none of the sera from 35 normal individuals reacted. A seroepidemiological survey of middle-school students revealed a positive rate of 17.0% (142/836), and 76.1% (105/138) of the serologically positive students were egg positive in stool examination. The egg positive rates in those with antibody at levels of 1+ to 4+ were 57.1% (28/49), 75.7% (28/37), 94.7% (36/38) and 92.9% (13/14) respectively. It is believed that Dot-IGSS can be used for the clinical diagnosis and epidemiological survey of clonorchiasis.

[A study on histopathology of iris with Nd: YAG and/or argon laser iridotomy]

Laser iridotomy including Nd: YAG, argon and Nd: YAG combined with argon was performed on 42 eyes of 25 chinchilla rabbits. The postoperative follow-up was 8 months. The histopathological changes of the irides at the sites of the various laser shots under light, transmission and scanning electron microscopic examinations were compared. The results show: (1) In regard to the Nd: YAG laser effect on the target tissue, the inherent elasticity of the tissue may play a more important role in curative effects of the therapy than the thickness of the tissue. (2) Every iris hole, < 200 microns in diameter, performed by Nd: YAG or < 450 microns, by argon or argon combined with Nd: YAG was closed by the first postoperative week. The histopathological findings demonstrate that the pigment epithelial proliferation and migration are more marked in the irides with argon laser iridotomy. (3) An insufficient coagulative burn of the argon laser may cause congestion of iris blood vessels and possibly, result in more severe bleeding during succedent Nd: YAG laser shots.

[Biomechanics of traction for treatment of lumber disc prolapse]

The intervertebral distance in 31 prolapsed discs under traction increased on the average by 1.34 mm, but in normal discs 0.87 mm. Of 47 prolapsed discs without traction, 29 had negative intradisc pressure, 10 zero, and 8 positive. The total average value of the pressure before traction was -1.3 kPa. Under lumber traction, the pressure decreased in 30 discs, unchanged in 8, and increased in 9, with the average value being -3.2 kPa. The intradisc pressure in 7 normal discs was contrary to the pressure in the prolapsed disc. The difference between the two groups was highly significant (P < 0.01). The pressure unchanged when the intervertebral distance of prolapsed disc unchanged under traction, but the pressure decreased as the distance increased in most cases under traction.

Cryptosporidium infection and diarrhea in rural and urban areas of Jiangsu, People's Republic of China

Screening of infants and children under age 15 years for Cryptosporidium oocysts in their stools was carried out in the suburb of Xuzhou City and six rural areas of Jiangsu Province. The infection rate varied from 0.7 to 5.06%. Of the total of 5,089 children examined, 89 (1.75%) were oocyst positive. The incidence was evidently higher in the group of children under age 4 years than it was in children from 4 to 15 years (P less than 0.01). Routine blood examination and immunoassay performed on blood samples from some of the infected children indicated that more than half of them had anemia and lower cellular immunity. Diarrhea was the main symptom of cryptosporidiosis. It was intermittent or persistent and was present in 57 of the 89 children positive for Cryptosporidium oocysts, while the other 32 children were asymptomatic carriers. Examination of stool specimens of adult members and domestic animals of about half of the infected families showed that two mothers, one pig, and one dog were positive for Cryptosporidium oocysts.

Computer-based solution to a clinical education problem in a physical therapy course

This article describes the solution to a logistical problem involving the assignment of multiple clinical experiences to students in an undergraduate physical therapy course. Physical therapy faculty members collaborated with a computer programmer to formulate a computer program that would satisfy the organizational needs imposed by this problem. We suggest that the skills of the physical therapist combined with those of a computer programmer can be used to generate effective, computer-based solutions to many other problems related to the organization of data and to decision making in physical therapy.