Anti-MUC-1 immunoliposomal doxorubicin in the treatment of murine models of metastatic breast cancer

The fate of breast cancer patients is dependent upon elimination or control of metastases. We studied the effect of antibody-targeted liposomes containing entrapped doxorubicin (DXR) on development of tumours in two models of breast cancer, pseudometastatic and metastatic, in mice. The former used the mouse mammary carcinoma cell line GZHI, which expresses the human MUC-1 gene (L. Ding, E.N. Lalani, M. Reddish, R. Koganty, T. Wong, J. Samuel, M.B. Yacyshyn, A. Meikle, P.Y.S. Fung, J. Taylor-Papadimitriou, B.M. Longenecker, Cancer Immunol. Immunother. 36 (1993) 9--17). GZHI cells seed into the lungs of Balb/c mice following intravenous injection. The latter used the 4T1-MUC1 cell line, a MUC-1 transfectant of the mouse mammary carcinoma cell line 4T1, which metastasizes from a primary mammary fatpad (mfp) implant to the lungs (C.J. Aslakson, F.R. Miller, Cancer Res. 52 (1992) 1399--1405). B27.29, a monoclonal antibody against the MUC-1 antigen, was used to target sterically stabilized immunoliposomes (SIL[B27.29]) to tumour cells. In vitro, SIL[B27.29] showed high specific binding to both GZHI and 4T1-MUC1 cells. The IC(50) of DXR-loaded SIL[B27.29] was similar to that of free drug for GZHI cells. In the pseudometastatic model, mice treated with a single injection of 6 mg DXR/kg in DXR-SIL[B27.29] at 24 h after cell implantation had longer survival times than those injected with non-targeted liposomal drug. In the metastatic model, severe combined immune deficiency mice given weekly injectionsx3 of 2.5 mg DXR/kg encapsulated in either targeted or non-targeted liposomes were almost equally effective in slowing growth of the primary tumour and reducing development of lung tumours. Surgical removal of the primary tumour from mfp, followed by various chemotherapy regimens, was attempted, but removal of the primary tumour was generally incomplete; tumour regrowth occurred and metastases developed in the lungs in all treatment groups. DXR-SL reduced the occurrence of regrowth of the primary tumour, whereas neither targeted liposomal drug or free drug prevented regrowth. We conclude that monoclonal antibody-targeted liposomal DXR is effective in treating early lesions in both the pseudometastatic and metastatic models, but limitations to the access of the targeted liposomes to tumour cells in the primary tumour compromised their therapeutic efficacy in treating the more advanced lesions.

Melatonin prevents delta-aminolevulinic acid-induced oxidative DNA damage in the presence of Fe2+

Delta-aminolevulinic acid (ALA), a heme precursor which accumulates during lead poisoning and acute intermittent porphyria, is reported to cause liver cancer. The carcinogenic mechanisms of ALA may relate to its ability to generate free radicals through metal-catalyzed oxidation which cause oxidative DNA damage. The aim of this study was to compare the efficacy of melatonin, trolox (vitamin E) and mannitol in altering DNA damage induced by ALA. Herein, we found, in the presence of Fe2+, that ALA-induced formation of 8-hydroxydeoxyguanosine in calf thymus DNA was dose and time-dependent. Melatonin, mannitol and trolox, all of which are free radical scavengers, inhibited the formation of 8-hydroxydeoxyguanosine in a concentration-dependent manner. The concentration of each (melatonin, mannitol and trolox) required to reduce DNA damage by 50%, i.e., the IC50, was 0.52, 0.84 and 0.90 mM, respectively.

Morphologic conversion of a neuroblastoma-derived cell line by E6-mediated p53 degradation

Neuroblastoma-derived tumor cells, unlike cells from other tumor types, characteristically express a wildtype but cytoplasmically sequestered p53 protein. To ascertain whether the p53 in these cells retained any physiological activity, we inactivated it in SK-N-SH cells, a neuroblastoma-derived cell line, by introducing the human papilloma virus type 16 E6 expression plasmid. Parent SK-N-SH cell cultures are composed of two cell types exhibiting characteristic morphologies designated neuroblastic (N-type) or substrate-adherent fibroblastic (S-type) cells, both of which have been shown to spontaneously transdifferentiate or interconvert. We report here that down-regulation of p53 resulted in conversion of SK-N-SH cells to the substrate-adherent fibroblast-like S-type cells. The morphologic conversion was accompanied by a loss of neurofilament expression, a marker for the neuronal N-type cells, an increase in the expression of vimentin, and a lack of responsiveness to retinoic acid-induced neuronal differentiation. Importantly, we did not observe N-type cells in the E6-transfected cell population, suggesting that they were incapable of transdifferentiating to the N-type morphology. We also tested the ability of these E6-transfected S-type cells to form colonies in soft agar and observed a markedly reduced capacity of these cells to do so when compared with the parent and mutant E6-transfected cells. These results suggest that p53 is required for the maintenance of the neuroblastic tumorigenic phenotype.

Melatonin directly scavenges hydrogen peroxide: a potentially new metabolic pathway of melatonin biotransformation

A potential new metabolic pathway of melatonin biotransformation is described in this investigation. Melatonin was found to directly scavenge hydrogen peroxide (H(2)O(2)) to form N(1)-acetyl-N(2)-formyl-5-methoxykynuramine and, thereafter this compound could be enzymatically converted to N(1)-acetyl-5-methoxykynuramine by catalase. The structures of these kynuramines were identified using proton nuclear magnetic resonance, carbon nuclear magnetic resonance, and mass spectrometry. This is the first report to reveal a possible physiological association between melatonin, H(2)O(2), catalase, and kynuramines. Melatonin scavenges H(2)O(2) in a concentration-dependent manner. This reaction appears to exhibit two distinguishable phases. In the rapid reaction phase, the interaction between melatonin and H(2)O(2) reaches equilibrium rapidly (within 5 s). The rate constant for this phase was calculated to be 2.3 x 10(6) M(-1)s(-1). Thereafter, the relative equilibrium of melatonin and H(2)O(2) was sustained for roughly 1 h, at which time the content of H(2)O(2) decreased gradually over a several hour period, identified as the slow reaction phase. These observations suggest that melatonin, a ubiquitously distributed small nonenzymatic molecule, might serve to directly detoxify H(2)O(2) in living organisms. H(2)O(2) and melatonin are present in all subcellular compartments; thus, presumably, one important function of melatonin may be complementary in function to catalase and glutathione peroxidase in keeping intracellular H(2)O(2) concentrations at steady-state levels.

Enalaprilat directly ameliorates in vitro cyclosporin nephrotoxicity in human tubulo-interstitial cells

BACKGROUND/AIMS

Several recent studies have suggested that angiotensin-converting enzyme (ACE) inhibitors ameliorate chronic cyclosporin A (CyA) tubulo-interstitial disease by mechanisms independent of their antihypertensive effects. The aim of the present study was to determine whether ACE inhibition exerts a direct beneficial effect on the tubulo-interstitium in an in vitro model of chronic CyA nephropathy.

METHODS

Primary cultures of human proximal tubular cells (PTC) and renal cortical fibroblasts (CF) were exposed for 24 h to CyA in the presence or absence of enalaprilat. Parameters of tubulo-interstitial nephrotoxicity were then measured including collagen synthesis (proline incorporation), tubular viability and function (thymidine incorporation, lactate dehydrogenase release, and apical sodium-hydrogen exchange), and secretion of insulin-like growth factor I, transforming growth factor beta 1 (TGFbeta1), and platelet-derived growth factor.

RESULTS

CyA promoted CF collagen synthesis, PTC cytotoxicity (suppressed viability, growth and sodium transport), and tubulo-interstitial fibrogenic cytokine release (CF secretion of insulin-like growth factor I and PTC secretion of TGFbeta1 and platelet-derived growth factor). Enalaprilat completely reversed the stimulatory effects of CyA on CF collagen synthesis (CyA + enalaprilat 6.40 +/- 0.50% vs. CyA alone 8.33 +/- 0.56% vs. control 6.57 +/- 0.62% vs. enalaprilat alone 5.55 +/- 0.93%, p < 0.05) and PTC secretion of TGFbeta1 (0.71 +/- 0.11, 1.13 +/- 0.09, 0.89 +/- 0.07, and 0.67 +/- 0.09 ng/mg protein/day, respectively, p < 0.05). However, the other manifestations of CyA toxicity were not significantly reversed by concomitant enalaprilat administration.

CONCLUSIONS

ACE inhibition directly prevents CyA-induced interstitial fibrosis, but not proximal tubule cytotoxicity, independently of haemodynamic and systemic renin-angiotensin system effects. Renoprotection may be partially afforded by directly preventing the tubular secretion of TGFbeta1.

High levels of melatonin in the seeds of edible plants: possible function in germ tissue protection

The seeds of plants represent the anlage of the next generation and are vital to their existence. Melatonin has been identified in the leaves and flowers of plants but not in seeds. In this study, we examined the seeds of 15 edible plants for the presence of melatonin which was extracted using cold ethanol. Melatonin was initially identified by radioimmunoassay and subsequently quantified and confirmed using high performance liquid chromatography. The physiological concentrations of melatonin in the 15 seeds studied ranged from 2 to 200 ng/g dry weight. The highest concentrations of melatonin were observed in white and black mustard seeds. This level of melatonin is much higher than the known physiological concentrations in the blood of many vertebrates. Since the seed, particularly its germ tissue, is highly vulnerable to oxidative stress and damage, we surmise that melatonin, a free radical scavenger, might be present as an important component of its antioxidant defense system. Thus, melatonin in seeds may be essential in protecting germ and reproductive tissues of plants from oxidative damage due to ultraviolet light, drought, extremes in temperature, and environmental chemical pollutants.

[Dynamic changes of serum pro-inflammatory cytokines and anti-inflammatory cytokines in patients with acute infection and the effect of Chinese herbal medicine intervention]

OBJECTIVE

To study the dynamic changes of serum pro-inflammatory cytokines and anti-inflammatory cytokines in patients with acute infection and to explore the effect of 912 compound, a Chinese herbal preparation for intervention.

METHODS

Forty patients with acute infection were randomly divided into 2 groups, 20 in the 912 group and 20 in the control group, and the levels of plasma endotoxin (lipopolysaccharide, LPS), serum pro-inflammatory cytokines, including tumor necrosis factor alpha (TNF alpha) and interleukin-6 (IL-6) and anti-inflammatory cytokines, including soluble TNF-RI, IL-4 and IL-10 were measured before and after treatment by using limulus reagent stroma azo-colored quantitative method and enzyme-linked immunosorbent assay (ELISA).

RESULTS

The level of LPS increased at the early stage of acute infection, the levels of pro- and anti-inflammatory cytokines were all elevated in various degrees, particularly obvious in IL-6, sTNF-RI, IL-4 and IL-10 and the elevations of the two were basically parallel. The TNF alpha, IL-6 and sTNF-RI were positively related with APACHE III scoring. The levels of LPS and inflammatory cytokines reduced to a different extent in accord with the improvement of condition after treatment, the levels of LPS, TNF alpha, IL-6 and IL-10 lowered more significantly in the 912 group than those in the control group (P < 0.05).

CONCLUSIONS

LPS, pro-inflammatory and anti-inflammatory cytokines play important roles in the acute infection process, they were important indexes for evaluating severity of infectious diseases. The Chinese herbal preparation 912 compound could reduce the blood levels of LPS, TNF alpha, IL-6, IL-10 and prevent the decrease of sTNF-RI so as to promote the recovery of patients.

Melatonin reduces rat hepatic macromolecular damage due to oxidative stress caused by delta-aminolevulinic acid

Delta-aminolevulinic acid, precursor of heme, accumulates in a number of organs, especially in the liver, of patients with acute intermittent porphyria. The potential protective effect of melatonin against oxidative damage to nuclear DNA and microsomal and mitochondrial membranes in rat liver, caused by delta-aminolevulinic acid, was examined. Changes in 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels, an index of DNA damage, and alterations in membrane fluidity (the inverse of membrane rigidity) and lipid peroxidation in microsomal and mitochondrial membranes, as indices of damage to lipid and protein molecules in membranes, were estimated. Measurements were made in rat liver after a 2 week treatment with delta-aminolevulinic acid (40 mg/kg b.w., every other day). To test the potential protective effects of melatonin, the indole was injected (i.p. 10 mg/kg b.w.) 3 times daily for 2 weeks. 8-OHdG levels and lipid peroxidation in microsomal membranes increased significantly whereas microsomal and mitochondrial membrane fluidity decreased as a consequence of delta-aminolevulinic acid treatment. Melatonin completely counteracted the effects of delta-aminolevulinic acid. Melatonin was highly effective in protecting against oxidative damage to DNA as well as to microsomal and mitochondrial membranes in rat liver and it may be useful as a cotreatment in patients with acute intermittent porphyria.

Molecular mimicry of human tumor antigen by heavy chain CDR3 sequence of the anti-idiotypic antibody

We isolated and characterized an anti-idiotype monoclonal antibody (AR42.1) which is capable of mimicking a distinct and specific epitope of MUC-1 antigen. The cDNA sequences coding for the AR42.1 variable regions were determined. We found significant amino acid homology between complementary determining regions 3 (CDR3) in the heavy chain of AR42.1 and the determinant epitope sequence of MUC-1. This 10 amino acid sequence may represent an "internal image" of the anti-idiotype antibody to the MUC-1 antigen, and could be used for development of a MUC-1 surrogate for immunotherapy.

Gelatinase and inhibitor expression in soft tissue sarcomas: lack of correlation with distant metastasis

The predominant mode of death for most patients with soft tissue sarcomas (STS) remains distant metastasis (DM). Current clinical predictors of DM are unreliable. Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) correlate with biologic aggression in other tumors. The gene expression of the gelatinase, MMP-2 and MMP-9, and their respective inhibitors, TIMP-1 and TIMP-2, in STS was evaluated. Twelve fresh-frozen surgical specimens from patients with large (>5 cm) STS were analyzed. Six patients developed DM while 6 survived disease-free (DFS) at a minimum follow-up of 13 months. Following mRNA isolation, reverse transcription-polymerase chain reaction was performed using primers for MMP-2, MMP-9, TIMP-1, and TIMP-2. Gene expression was determined by band densitometry. Ratios of MMP-9/TIMP-1 and MMP-2/ TIMP-2 gene expression as well as MMP-2 protein activation ratio (active/inactive enzyme determined by gelatin zymography) were analyzed for correlation with DM and DFS. MMP-2 gene was expressed in 12 specimens, while MMP-9 was detectable in 9. Relative levels of MMP-2 and MMP-9, MMP2/TIMP-2 ratio, and MMP-9/TIMP-1 ratio were not significantly correlated with DM. Poor DFS was significantly correlated with high MMP-9/TIMP-1 ratio (p = 0.02). Active MMP-2 protein was detected in 12 specimens, while active MMP-9 protein was detected in 2. No association was found between MMP-2 protein activation ratio and DM or DFS. While MMP-2 gene expression and protein activity occurred in these 12 specimens, gelatinase/inhibitor ratios (for both MMP-2 and MMP-9) appear to be poor predictors of DM in STS.

[A procedure for developing selective isolation of Pseudonocardiacetes from soil samples]

Pseudonocardiacetes are a group of rare-actinomyces with type IV cell walls and without mycolic acids. Five different selective isolation media S1, S2, S3, S4 and S5 were devised and practiced to improve their selective isolation efficiency. The media were detected by 33 type strains of Pseudonocardiaceae, 4 strains of Saccharothrix and 15 type strains of Streptomyces cultured on them. Soil samples were examined on media S1 ad S2 compared with glucose-asparagine agar. It shows that media S1 and S2 are effective for growth and isolation of Amycolata, Pseudonocardia, Saccharomonospora and other genera of Pseudonocardiaceae.

Increased levels of oxidatively damaged DNA induced by chromium(III) and H2O2: protection by melatonin and related molecules

Chromium (Cr) compounds are known occupational and environmental carcinogens. This trace element is found in the workplace primarily in the valence forms Cr(III) and Cr(VI). Cr(III), which was thought originally to be relatively nontoxic, was recently found to be more reactive toward purified DNA than was chromium(VI). Herein, we examined the ability of Cr(III) to induce oxidative DNA damage by measuring the formation of 8-hydroxydeoxyguanosine (8-OH-dG) in purified calf thymus DNA incubated with CrCl3 plus H2O2. In this system we observed that the Cr(III)-induced formation of 8-OH-dG in isolated DNA was both dose- and time-dependent. When melatonin and related molecules, including 6-methoxy-1,2,3,4-tetrahydro-beta-carboline (pinoline), N-acetylserotonin, 6-hydroxymelatonin and indole-3-propionic acid, were co-incubated with CrCl3 plus H2O2, the accumulations of 8-OH-dG in DNA samples were markedly inhibited in a concentration-dependent manner. The concentrations of each indole required to reduce DNA damage by 50%, i.e. the IC50 values, were 0.48, 0.51, 0.88, 1.00 and 3.08 microM for pinoline, melatonin, N-acetylserotonin, 6-hydroxymelatonin and indole-3-propionic acid, respectively. These results suggest that one of the mechanisms by which Cr(III) may induce cancer is via Fenton-type reactions which generate the hydroxyl radical (*OH). The findings also indicate that the protective effects of melatonin and related molecules against Cr(III)-induced carcinogenesis relate to their direct *OH scavenging ability which thereby reduces the formation of the damaged DNA product, 8-OH-dG.

Protective effects of melatonin against oxidation of guanine bases in DNA and decreased microsomal membrane fluidity in rat liver induced by whole body ionizing radiation

The aim of the study was to examine the potential protective effect of melatonin against whole body ionizing radiation (800 cGy). Changes in 8-hydroxy-2'-deoxyguanosine (8-OH-dG) levels, an index of DNA damage, and alterations in membrane fluidity (the inverse of membrane rigidity) and lipid peroxidation in microsomal membranes, as indices of damage to lipid and protein molecules in membranes, were estimated. Measurements were made in rat liver, 12 h after their exposure to radiation. To test the potential protective effects of melatonin, the indole was injected (i.p. 50 mg/kg b.w.) at 120, 90, 60 and 30 min prior to radiation exposure. Both 8-OH-dG levels and microsomal membrane rigidity increased significantly 12 h after radiation exposure. Melatonin completely counteracted the effects of ionizing radiation. Changes in 8-OH-dG levels and membrane fluidity are early sensitive parameters of DNA and microsomal membrane damage, respectively, induced by ionizing radiation and our findings document the protective effects of melatonin against ionizing radiation.

Bone morphogenetic protein-2 blocks MDA MB 231 human breast cancer cell proliferation by inhibiting cyclin-dependent kinase-mediated retinoblastoma protein phosphorylation

Bone morphogenetic protein-2 (BMP-2) has been shown to act as an antiproliferative agent for a number of different cell types. We show that BMP-2 dose-dependently inhibits growth of MDA MB 231 human breast cancer cells. Epidermal growth factor (EGF) stimulates DNA synthesis and entry of these cells into the S-phase. BMP-2 inhibits EGF-induced DNA synthesis by arresting them in G1 phase of the cell cycle. BMP-2 increases the level of cyclin kinase inhibitor p21. Furthermore, we show that exposure of MDA MB 231 cells to BMP-2 stimulates association of p21 with cyclin D1 and with cyclin E resulting in the inhibition of their associated kinase activities. Finally, BMP-2 treatment is found to cause hypophosphorylation of the retinoblastoma protein (pRb), a key regulator of cell cycle progression. Our data provide a mechanism for the antiproliferative effect of BMP-2 in the breast cancer cells.

Cardiac natriuretic peptides and continuously monitored atrial pressures during chronic rapid pacing in pigs

Changes in atrial natriuretic peptide (ANP), N-terminal proatrial natriuretic peptide and brain natriuretic peptide (BNP) were evaluated in relation to continuously monitored atrial pressures in a pacing model of heart failure. Pigs were subjected to rapid atrial pacing (225 beats min-1) for 3 weeks with adjustments of pacing frequencies if the pigs showed overt signs of cardiac decompensation. Atrial pressures were monitored by a telemetry system with the animals unsedated and freely moving. Left atrial pressure responded stronger and more rapidly to the initiation of pacing and to alterations in the rate of pacing than right atrial pressure. Plasma natriuretic peptide levels were measured by radioimmunoassay and all increased during pacing with BNP exhibiting the largest relative increase (2.9-fold increase relative to sham pigs). Multiple regression analysis with dummy variables was used to evaluate the relative changes in natriuretic peptides and atrial pressures and the strongest correlation was found between BNP and left atrial pressure with R 2=0.81. Termination of pacing resulted in rapid normalization of ANP values in spite of persistent elevations in atrial pressures. This may reflect an increased metabolism or an attenuated secretory response of ANP to atrial stretch with established heart failure. In conclusion, 3 weeks of rapid pacing induced significant increases in atrial pressures and natriuretic peptide levels. All the natriuretic peptides correlated with atrial pressures with BNP appearing as a more sensitive marker of cardiac filling pressures than ANP and N-terminal proatrial natriuretic peptide.

Chromium(III)-induced 8-hydroxydeoxyguanosine in DNA and its reduction by antioxidants: comparative effects of melatonin, ascorbate, and vitamin E

Chromium compounds are well documented carcinogens. Cr(III) is more reactive than Cr(VI) toward DNA under in vitro conditions. In the present study, we investigated the ability of Cr(III) to induce oxidative DNA damage by examining the formation of 8-hydroxydeoxyguanosine (8-OH-dG) in calf thymus DNA incubated with CrCl(3) plus H(2)O(2). We measured 8-OH-dG using HPLC with electrochemical detection. In the presence of H(2)O(2), we observed that Cr(III)-induced formation of 8-OH-dG in isolated DNA was dose and time dependent. Melatonin, ascorbate, and vitamin E (Trolox), all of which are free radical scavengers, markedly inhibited the formation of 8-OH-dG in a concentration-dependent manner. The concentration that reduced DNA damage by 50% was 0.51, 30.4, and 36.2 microM for melatonin, ascorbate, and Trolox, respectively. The results show that melatonin is 60- and 70-fold more effective than ascorbate or vitamin E, respectively, in reducing oxidative DNA damage in this in vitro model. These findings also are consistent with the conclusion that the carcinogenic mechanism of Cr(III) is possibly due to Cr(III)-mediated Fenton-type reactions and that melatonin's highly protective effects against Cr(III) relate, at least in part, to its direct hydroxyl radical scavenging ability.

Changes in lipid peroxidation during pregnancy and after delivery in rats: effect of pinealectomy

Pregnancy is a physiological state accompanied by a high energy demand of many bodily functions and an increased oxygen requirement. Because of the increased intake and utilization of oxygen, increased levels of oxidative stress would be expected. In the present study, the degree of lipid peroxidation was examined in different tissues from non-pregnant and pregnant rats after the delivery of their young. Melatonin and other indole metabolites are known to be direct free radical scavengers and indirect antioxidants. Thus the effect of pinealectomy at 1 month before pregnancy on the accumulation of lipid damage was investigated in non-pregnant and pregnant rats after the delivery of their young. Malonaldehyde and 4-hydroxyalkenal concentrations were measured in the lung, uterus, liver, brain, kidney, thymus and spleen from intact and pinealectomized pregnant rats soon after birth of their young and at 14 and 21 days after delivery. The same parameters were also evaluated in intact and pinealectomized non-pregnant rats. Shortly after delivery, lipid oxidative damage was increased in lung, uterus, brain, kidney and thymus of the mothers. No differences were detected in liver and spleen. Pinealectomy enhanced this effect in the uterus and lung. It is concluded that during pregnancy high levels of oxidative stress induce an increase in oxidative damage to lipids, which in some cases is inhibited by the antioxidative actions of pineal indoles.

Pharmacology and physiology of melatonin in the reduction of oxidative stress in vivo

This brief resume summarizes the evidence which shows that melatonin is a significant free radical scavenger and antioxidant at both physiological and pharmacological concentrations in vivo. Surgical removal of the pineal gland, a procedure which lowers endogenous melatonin levels in the blood, exaggerates molecular damage due to free radicals during an oxidative challenge. Likewise, providing supplemental melatonin during periods of massive free radical production greatly lowers the resulting tissue damage and dysfunction. In the current review, these findings are considered in terms of neurodegenerative diseases, cancer, ischemia/reperfusion injury and aging. Besides being a highly effective direct free radical scavenger and indirect antioxidant, melatonin has several features that make it of clinical interest. Thus, melatonin is readily absorbed when it is administered via any route, it crosses all morphophysiological barriers, e.g., blood-brain barrier and placenta, with ease, it seems to enter all parts of every cell where it prevents oxidative damage, it preserves mitochondrial function, and it has low toxicity. While blood melatonin levels are normally low, tissue levels of the indoleamine can be considerably higher and at some sites, e.g., in bone marrow cells and bile, melatonin concentrations exceed those in the blood by several orders of magnitude. What constitutes a physiological level of melatonin must be redefined in terms of the bodily fluid, tissue and subcellular compartment being examined.

Changes in lipid peroxidation during pregnancy and after delivery in rats: effect of pinealectomy

Pregnancy is a physiological state accompanied by a high energy demand of many bodily functions and an increased oxygen requirement. Because of the increased intake and utilization of oxygen, increased levels of oxidative stress would be expected. In the present study, the degree of lipid peroxidation was examined in different tissues from non-pregnant and pregnant rats after the delivery of their young. Melatonin and other indole metabolites are known to be direct free radical scavengers and indirect antioxidants. Thus the effect of pinealectomy at 1 month before pregnancy on the accumulation of lipid damage was investigated in non-pregnant and pregnant rats after the delivery of their young. Malonaldehyde and 4-hydroxyalkenal concentrations were measured in the lung, uterus, liver, brain, kidney, thymus and spleen from intact and pinealectomized pregnant rats soon after birth of their young and at 14 and 21 days after delivery. The same parameters were also evaluated in intact and pinealectomized non-pregnant rats. Shortly after delivery, lipid oxidative damage was increased in lung, uterus, brain, kidney and thymus of the mothers. No differences were detected in liver and spleen. Pinealectomy enhanced this effect in the uterus and lung. It is concluded that during pregnancy high levels of oxidative stress induce an increase in oxidative damage to lipids, which in some cases is inhibited by the antioxidative actions of pineal indoles.

Molecular basis of androgen receptor diseases

androgens act through a single intracellular androgen receptor (AR) which is encoded by a single-copy gene in the X chromosome. Disruption of the AR by genetic mutation results in complete androgen insensitivity syndrome (CAIS) and the female phenotype in otherwise healthy 46XY individuals. Although CAIS is the best known phenotype, recent studies from our laboratory and elsewhere show that malfunction of the AR is associated with many androgen-regulated diseases or conditions that cross traditional clinical disciplines ranging from paediatrics (ambiguous genitalia), gynaecology (primary amenorrhoea), urology (prostate cancer), neurology (spinal bulbar muscular atrophy), reproductive medicine (male infertility), orthopedics (rheumatoid arthritis), oncology (breast cancer) and dermatology (hirsutism, baldness and acne). Of particular interest are the roles that polymorphic CAG trinucleotide repeat tracts and subtle mutations in the AR ligand-binding domain have in the aetiology of male infertility and prostate cancer, two conditions affecting large numbers of patients. Novel mechanisms of pathogenesis have been uncovered in these cases, and they involve defective protein-protein interactions with coregulator molecules such as TIF2 (transcriptional intermediary factor 2). Knowledge of the critical role that the AR plays in the pathogenesis of these diverse conditions has led to improved diagnostic methods and successful therapy.

Differential responses of plasma atrial and brain natriuretic peptides to acute alteration in atrial pressure in pigs

To describe the differential dynamic responses of atrial natriuretic peptide (ANP), N-terminal proatrial natriuretic peptide (Nt-proANP) and brain natriuretic peptide (BNP) to acute changes in atrial pressure, 6 pigs were studied during and after a 24-h period of rapid atrial pacing (225 bpm). During pacing, left atrial pressure increased acutely. ANP plasma concentrations showed a sharp initial peak followed by a decline, but remained significantly increased throughout the 24-h period. Nt-proANP followed a smoother pattern, increasing significantly only after 24 h. BNP increased significantly after 8 h after pacing and even more after 24 h. An opposite but similarly differential pattern of peptide responses was found in the post-pacing period. The different responses in ANP, Nt-proANP and BNP plasma concentrations may reflect the different mechanisms of regulation of secretion as well as plasma clearance. If the present findings reflect the acute clinical situation in humans, they may be of diagnostic relevance. An isolated ANP elevation would indicate a recent acute pressure increase, while elevation of two or more natriuretic peptides would point to a pressure increase of longer duration.

Melatonin reduces oxidative neurotoxicity due to quinolinic acid: in vitro and in vivo findings

The in vivo and in vitro effects of melatonin on quinolinic acid-induced oxidative damage in rat brain were determined. The concentrations of malonaldehyde and 4-hydroxyalkenals were assayed as an index of oxidatively damaged lipid. In in vitro experiments, the increase in malonaldehyde and 4-hydroxyalkenals concentrations induced by quinolinic acid were concentration-dependent and time-dependent. The accumulation of products of lipid peroxidation induced by quinolinic acid were very significantly reduced by melatonin in a concentration-dependent manner. Additionally, at the highest concentrations of melatonin used in quinolinic acid treated homogenates, it reduced the levels of oxidatively damaged lipid products below those measured in control homogenates (no quinolinic acid or melatonin). When quinolinic acid (200 mg/kg) was intraperitonally injected into 11-day-old rats, lipid peroxidation in the brain was significantly increased 24 hours later compared to levels in control rats. When melatonin (10 mg/kg) was injected i.p. 30 min before and 4 and 20 hours after the administration of quinolinic acid, the increased lipid peroxidation induced by quinolinic acid was significantly reduced. Likewise, neurobehavioral signs associated with quinolinate administration were attenuated by melatonin. These results show that both in vitro and in vivo pharmacological levels of melatonin confer protection against quinolinic acid-induced oxidative toxicity in the brain. The findings also indicate that melatonin may be pharmacologically useful in combatting quinolinic neurotoxicity which is associated with several acute and chronic neurodegenerative neurological diseases.

5-methoxytryptophol preserves hepatic microsomal membrane fluidity during oxidative stress

Lipid peroxidation is a degenerative chain reaction in biological membranes that may be initiated by exposure to free radicals. This process is associated with changes in the membrane fluidity and loss of several cell membrane-dependent functions. 5-methoxytryptophol (ML) is an indole isolated from the mammalian pineal gland. The purpose of this study was to investigate the effects of ML (0. 01mM-10mM) on membrane fluidity modulated by lipid peroxidation. Hepatic microsomes obtained from rats were incubated with or without ML (0.01-10 mM). Then lipid peroxidation was induced by FeCl(3), ADP, and NADPH. Membrane fluidity was determined using fluorescence spectroscopy. Malonaldehyde (MDA) +4-hydroxyalkenals (4-HDA) concentrations were estimated as an indicator of the degree of lipid peroxidation. With oxidative stress, membrane fluidity decreased and MDA+4-HDA levels increased. ML (0.01-3 mM) reduced membrane rigidity and the rise in MDA+4-HDA formation in a concentration-dependent manner. 10 mM ML protected against lipid peroxidation but failed to prevent the membrane rigidity. In the absence of oxidative reagents, ML (0.3-10 mM) decreased membrane fluidity whereas MDA+4-HDA levels remained unchanged. This indicates that ML may interact with membrane lipids. The results presented here suggest that ML may be another pineal indoleamine (in addition to melatonin) that resists membrane rigidity due to lipid peroxidation.

Finite element study on 1-D array transducer design

A comprehensive study using finite element analysis (FEA) was performed on 1-D transducer arrays. Crosstalk reduction, subdicing effects, directivity pattern, and baffle effects were quantified numerically. It was found that the directivity pattern strongly depends on the transducer size and kerf filling materials. The FEA is particularly powerful in revealing the inhomogeneous nature of the vibrational characteristics of the transducer surface, which allows more accurate beam pattern computation in 3-D. The simulated directivity pattern also was satisfactorily verified by experimental measurements.

Inhibitory effects of melatonin on ferric nitrilotriacetate-induced lipid peroxidation and oxidative DNA damage in the rat kidney

Ferric nitrilotriacetate (Fe-NTA) is a known complete renal carcinogen which induces lipid peroxidation and oxidative DNA damage in rat kidney. In this study, the in vivo and in vitro effects of melatonin on Fe-NTA-induced lipid and oxidative DNA damage were determined. The levels of malondialdehyde (MDA) and 4-hydroxyalkenals (4-HDA) were assayed as an index of lipid peroxidation and the levels of 8-hydroxydeoxyguanosine (8-OH-dG) as an endpoint of oxidative DNA damage. In in vitro studies, the increased levels of MDA and 4-HDA induced by Fe-NTA were observed to be dose-dependent and time-dependent. The increase in lipid peroxidation was inhibited by melatonin in a concentration-dependent manner. When Fe-NTA(15 mg Fe/kg body weight) was intraperitoneally injected into rats, the levels of MDA + 4-HDA and 8-OH-dG in the rat kidney were increased 1 h after its administration as compared to levels of these constituents in the control group. Pretreatment with melatonin (25 mg/kg or 50 mg/kg) 30 min before the Fe-NTA injection resulted in a significant reduction in the levels of lipid peroxidation and 8-OH-dG induced by Fe-NTA in the rat kidney. These results are consistent with the conclusion that the toxicity of Fe-NTA is due to the generation of reactive oxygen species and that melatonin's protective effects relate to its direct radical scavenging ability and due to other antioxidative processes induced by the indole.

Melatonin reduces lipid peroxidation and tissue edema in cerulein-induced acute pancreatitis in rats

Since oxygen free radicals and lipid peroxidation have been implicated in the pathogenesis of an early stage of acute pancreatitis, we examined whether melatonin, a recently discovered free-radical scavenger, could attenuate pancreatic injury in Sprague-Dawley rats with cerulein-induced pancreatitis. Acute pancreatitis was induced by four intraperitoneal injections of cerulein (50 microg/kg body wt) given at 1-hr intervals. Thirty minutes after the last cerulein injection, the rats were killed and the degree of pancreatic edema, the level of lipid peroxidation in the pancreas, and serum amylase activity were increased significantly. Pretreatment with melatonin (10 or 50 mg/kg body wt) 30 min before each cerulein injection resulted in a significant reduction in pancreatic edema and the levels of lipid peroxidation. Serum amylase activity, however, was not significantly influenced by either dose of melatonin. Moreover, we found that cerulein administration was associated with stomach edema as well as high levels of lipid peroxidation in the stomach and small intestine, which were also reduced by melatonin. Melatonin's protective effects in cerulein-treated rats presumably relate to its radical scavenging ability and to other antioxidative processes induced by melatonin.

High physiological levels of melatonin in the bile of mammals

Bile is an important physiological bodily fluid which functions in the regulation of cholesterol metabolism, promotes the absorption of lipid and fat-soluble vitamins by the gut and serves in the excretion of toxic substances from the liver. Conversely, due to autooxidative processes bile is highly toxic to the hepatocyte and gastrointestinal epithelium. In this investigation, extremely high day time physiological levels of the endogenous antioxidant, melatonin, were measured in the bile of several mammals including rat, guinea pig, rabbit, pig, monkey and humans. Melatonin concentrations in the bile samples ranged from 2,000 to 11,000 pg/ml when measured by radioimmunoassay (RIA). These melatonin levels in bile are 2 to 3 orders of magnitude higher than those in day time serum. The presence of melatonin in bile was confirmed by HPLC with an electrochemical detector. This method, like the RIA, also documented very high levels of melatonin in bile. The presence of high levels of melatonin in bile may be essential to prevent oxidative damage to biliary and small intestinal epithelium induced by bile acids and oxidized cholesterol derivatives.

Augmentation of indices of oxidative damage in life-long melatonin-deficient rats

The chief pineal secretory product, melatonin, is an efficient free radical scavenger and antioxidant. The current study tested whether the life-long reduction of endogenous melatonin levels due to pinealectomy would influence the accumulation of oxidatively damaged products as the animals aged. Rats were either pinealectomized or sham operated when they were 2-months-old. At 25 months of age these animals were killed along with 2-month-old controls. Aging in the pineal-intact animals was associated with increased levels of lipid peroxidation products (malondialdehyde and 4-hydroxyalkenals in the lung, kidney and skin), rises in an oxidatively damaged DNA product (8-hydroxy-deoxyguanosine in liver, kidney and pancreas), and in the levels of protein carbonyls (in the liver). Likewise, advanced age was associated with a significant decrease in membrane fluidity (increased membrane rigidity) of hepatic microsomes in pineal-intact rats. For all of these parameters and in a number of organs, pinealectomy caused further increases in the indices of oxidative damage. Consistent with previous suggestions, the implications of these findings is that aging is associated with the augmented accumulation of oxidatively damaged macromolecules and that these increases are exaggerated when a relative melatonin deficiency is induced by pinealectomy. The findings are consistent with the idea that the accelerated accumulation of oxidatively damaged products after pinealectomy was due to reduction in melatonin since it functions as a free radical scavenger and antioxidant. On the other hand, other pineal secretory products that were reduced as a consequence of pineal removal may have also been responsible for some of the observed changes.

Intermittent high glucose enhances cell growth and collagen synthesis in cultured human tubulointerstitial cells

AIMS/HYPOTHESIS

We investigated the effects of constant and intermittently increased glucose concentrations on human proximal tubule cells and cortical fibroblasts in primary culture.

METHODS

Cells were grown to confluence and then exposed for 4 days to 6.1 mmol/l D-glucose (normal), 25 mmol/l D-glucose (high), or 6.1 mmol/l alternating with 25 mmol/l D-glucose on a daily basis.

RESULTS

In proximal tubular cells, exposure to high glucose caused an 11 % increase in thymidine uptake (p < 0.05), a 230 % increase in secretion of transforming growth factor beta 1 (TGF-beta1; p < 0.05) and a 393 % increase in platelet derived growth factor. Intermittent exposure to high glucose caused thymidine uptake to further increase by 42 % (p < 0.01) and TGF-beta1 secretion by 352 % (p < 0.01) but no additional increase in platelet-derived growth factor secretion was observed. Cellular protein content increased by 27 % (p < 0.05) and collagen synthesis by 29 % (p < 0.05), changes that were not observed in cells constantly exposed to high glucose. In cortical fibroblasts constant exposure to high glucose caused a 35 % increase in thymidine uptake (p < 0.01). Intermittently high glucose increased thymidine incorporation a further 58 % (p < 0.001), collagen synthesis by 65 % (p < 0.01) and insulin-like growth factor binding protein 3 secretion by 216 % (p < 0.01).

CONCLUSION/INTERPRETATION

In cultured human tubulointerstitial cells, increased glucose concentrations change cell growth, collagen synthesis and cytokine secretion. These effects are enhanced following intermittent exposure to high glucose, indicating that short lived excursions in glycaemic control have important pathological effects on the human tubulointerstitium.

[Clinical observation on 51 patients of acute myocardial infarction treated with thrombolytic therapy combined with Chinese herbal medicine]

OBJECTIVE

To assess the efficacy of thrombolytic therapy combined with Chinese herbal medicine (CHM) in treating acute myocardial infarction (AMI).

METHODS

One hundred and one cases of AMI were divided randomly into two groups. The treated group treated with thrombolytic therapy combined with CHM and the control group treated with thrombolytic therapy alone. The criteria of patency of coronary artery were conducted according to the referential standard of thrombolytic therapy in treating AMI introduced by Chinese Angiocardiopathy Medical Journal, 1991.

RESULTS

The patency rate of coronary artery of the two groups were 68.63% and 56.00%, the four-week mortality 3.92% and 10.00%, hemorrhage occurrence 1.96% and 10.00%, congestive heart failure occurrence 5.88% and 16.00%, severe arrhythmia occurrence 11.76% and 22.00%, and the shock occurrence 3.92% and 8.00% respectively. The difference between the two groups was significant, P < 0.01, P < 0.05.

CONCLUSION

The effect of the treated group was better and the complication occurrence of the treated group was lower than those of the control group.

[The thumb reconstruction by transferring the injured index finger with pedicles]

OBJECTIVE

In order to inquire the methods of thumb reconstruction by transferring the index finger with incomplete conditions of nerve or blood vessels.

METHODS

From April 1987 to October 1997, 6 cases were treated by 3 kinds of operative methods according to the damage type of thumb and complications injures of the rest of hand: 1. transferring the index finger with pedicle without proximal phalanx, 2. transferring the index finger with palmar nerve and blood vessels, and dorsal skin pedicle, 3. transferring the index finger with compound pedicle.

RESULTS

All 6 cases of thumb reconstruction were successful. Followed up 6 months to 2 years, the pinching and gribing functions in 6 cases were completely recovered, and the sensation were partly recovered.

CONCLUSION

The operative method of thumb reconstruction had following advantages: Simple operation, high survival rate and certain function recovery. It can enlarge the indications of thumb reconstruction.

Defense mechanisms of urinary bladder: studies on antimicrobial polypeptides from bladder mucosa

The acid-soluble extract of the bladder mucosal surface was obtained by washing out the bladder with dilute acetic acid in the presence of protease inhibitors. The wash-out materials from rats, rabbits, pigs, and humans manifested strong bactericidal activity against E. coli in vitro. The ultrafiltrate of the human material, which contained two major peptides with apparent molecular masses of 6.7 kD and 8.5 kD, respectively, showed potent bactericidal activity against E. coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Streptococcus sanguis. Three antibacterial polypeptides (PiBPs) were purified from the porcine material. The molecular masses of PiBP-5, PiBP-11 and PiBP-25 were 5773.3 Da, 11127.8 Da and 25073 Da, respectively. PiBP-5 was unusually rich in glycine, serine and threonine residues (20.0, 16.3 and 10.4 mol%, respectively), and N-terminal amino acid sequencing revealed that PiBP-5 was homologous (83.3% identity in an 18 residue overlay) to the "tail" of human cytokeratin-7. Although the amino acid compositions of PiBP-11 and PiBP-25 were established, both had blocked N-termini and primary sequence data were not obtained. These results provided evidence indicating that the presence of peptides in the bladder mucosa could enable it to kill adherent bacteria.

[Determination of 14 rare earth impurities in Y2O3 by petroleum sulfoxide extraction chromatography]

Petroleum sulfoxide-NH4SCN extraction chromatography was developed for the separation of Y from other rare earth elements. Some chromatographic parameters were chosen and separation factors between Y and other rare earth elements were determined. A column of resin coated with petroleum sulfoxide was used. The Y in the sample was eluted with NH4SCN, then titrated with EDTA. The recovery was 67%-120% and relative standard deviation +/- 4.0%-19.4%. This method can be applied to the determination of trace amounts of rare earth impurities in Y2O3 with a purity of 99.9999%-99.99999%.

[Determination of rare-earth impurities in ultra-highly pure Er2O3 and Ho2O3 by [HEH(HEP)] extraction chromatography-atomic emission spectrometry]

This article applied [HEH(HEP)] (2-ethyhexyldrogen-2-ethylhexyl phosphonate) extraction chromatography to separate 14 rare earth impurities from ultra-highly pure Er2O3 and Ho2O3, and then the impurities were determined by atomic emission spectrometry. The average percentage recovery for each element is in the range of 70%-140%. The relative standard deviations of the determination are +/- 3.3%-2.2%. This method can be applied to the determination of the trace amounts of rare eath impurities in Er2O3 and Ho2O3 with a purity of 99.9999%-99.99999%.

[Taxonomic study of four isolates of Saccharomonospora]

Four strains, 19.1, 22.1, 202, and 212, were isolated from the soil samples of Guangxi province in China. Basing on their morphological and cell chemical characteristics(cell wall type IV, sugar type A, without mycolic acids), they were circled into the genus of Saccharomonospora. They were studied with 7 type strains of the 5 currently recognized species in the genus. The results of Ribotyping suggest that strain 19.1 blongs to the species of S. viridis, strain 202 is a member of S. caesia, strain 22.1 and strain 212 are the same species, which is different to the 5 currently known species. It is closely related to S. viridis. However, the further classification of these two strains at species level needs 16S rRNA sequence date.

[Simultaneous analysis of histamine and noradrenaline in human plasma by high performance liquid chromatography/electrochemical detection]

This paper reports a reversed-phase high performance liquid chromatographic method for the simultaneous separation and determination of histamine(Hist) and noradrenaline(NA) in human plasma by means of pre-column derivatization of Hist and NA with OPA in the presence of 2-mercaptoethanol. The analysis was carried out with Partisil ODS column, V[sodium acetate buffer solution(pH 4.90)]:V(acetonitrile) = 7:3 as mobile phase and 3-methylhistamine as internal standard. The detector potential was +0.7 V for both compounds to keep minimum background noise. A linear relationship between the electrochemical signal and the compound mass concentrations was obtained. The minimum detectable limit was 15 ng/L (S/N = 3). An example of application of the method to the determination of Hist and NA in human plasma is presented.

Melatonin protects hippocampal neurons in vivo against kainic acid-induced damage in mice

In this investigation, 40 mg/kg of the excitatory neurotoxin kainic acid (KA) was subcutaneously administered to CD2-F1 mice. In this mouse strain morphological damage induced by KA in the hippocampus was markedly concentrated in the CA3 pyramidal neurons. Neuronal injury was accompanied by several pathological neurobehavioral activities including arching of tail, tremors and seizures, and by certain biochemical changes, i.e., increased lipid peroxidation products (LPO) in the brain. When melatonin was injected intraperitoneally at a single dose of 5 mg/kg 10 min before KA administration, it significantly reduced these pathological neurobehavioral changes and almost completely attenuated the increase in LPO and morphological damage induced by KA. The neuroprotective effect of melatonin against KA-induced brain damage in mice is believed to be in part related to its oxygen radical scavenging properties as well as its antiepileptic and GABA receptor regulatory actions. Considering melatonin's relative lack of toxicity and ability to enter the brain, these results along with previous evidence suggest that melatonin, which is a natural substance, may be useful in combating free radical-induced neuronal injury in acute situations such as stroke and brain trauma as well as neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease that have free radicals as causative factors.

Expression of a fusion protein of scFv-biotin mimetic peptide for immunoassay

We constructed two fusion proteins of scFv linked to biotin mimetic sequence (BMS) via different linkers, and expressed them in the Pichia pastoris expression/secretion system. We found that both bi-functional scFv proteins exhibited their intrinsic binding activities to antigen CA125 determined in competitive radioimmunoassay experiments, but the fusion protein with a spacer between the scFv and BMS (scFv-spacer-BMS) showed higher binding activity of streptavidin than the one with c-Myc peptide as a linker.

Ischemia/reperfusion-induced arrhythmias in the isolated rat heart: prevention by melatonin

Cardiac arrhythmias during ischemia/reperfusion are believed to be related to free radicals generated in the heart especially during the period of reperfusion. Since melatonin functions as a free radical scavenger and antioxidant, the ability of this molecule to influence cardiac arrhythmias was investigated. The pineal secretory product, melatonin, reduced the incidence and severity of arrhythmias induced by ischemia/reperfusion due to ligation of the anterior descending coronary artery in the isolated rat heart. Melatonin was either infused during both the ischemia and reperfusion periods or only late in the ischemia period and throughout reperfusion. The percentage of hearts that developed cardiac arrhythmias during reperfusion as indicated by the incidence of premature ventricular contraction (PVC) and ventricular fibrillation (VF) were recorded. Melatonin either infused during both the ischemia and reperfusion periods or during essentially the period of reperfusion greatly reduced PVC and VF due to occlusion and reopening the anterior descending coronary artery. Presumably melatonin's beneficial effect in reducing cardiac arrhythmias was due in part to its free radical scavenging activity, which is greatly assisted by the rapidity with which it is taken up into cells. Previous studies have shown that vitamin C is effective in reducing the severity of cardiac arrhythmias induced by ischemia/reperfusion; thus, we also compared the efficacy of melatonin with this well-known antioxidant. Melatonin was more potent than vitamin C in protecting against arrhythmias induced by ischemia/reperfusion. Besides melatonin's function as a broad spectrum free radical scavenger, melatonin may have also reduced cardiac arrhythmias due to its regulation of intracellular calcium levels, i.e., by preventing calcium overloading, or due to its ability to suppress sympathetic nerve function and reduce adrenergic receptor function in the myocardium. Additional studies into the mechanisms of melatonin's action in reducing cardiac arrhythmias due to ischemia/reperfusion or other causes are warranted because of the possible application of this information to humans with heart disease.

2-Nitropropane-induced lipid peroxidation: antitoxic effects of melatonin

The degree of lipid peroxidation (LPO) as indicated by the levels of thiobarbituric acid reactive substances, malondialdehyde (MDA) and 4-hydroxyalkenals (4-HDA), and the activity of sorbitol dehydrogenase (SDH) in serum as parameters of hepatotoxicity were studied in rats treated with a single intraperitoneal (i.p.) injection of the hepatocarcinogen 2-nitropropane (2-NP). Since melatonin, the main secretory product of the pineal gland, has been shown to protect against a number of toxic agents, it was given 30 min before 2-NP to test its protective effect against 2-NP toxicity. Significant increases in LPO in liver (P<0.0001), lung (P<0.05) and kidney (P<0.0001) were observed 24 h after 4 mmol/kg 2-NP while serum SDH activity was increased 470-fold. All parameters showed time (0, 4, 8, 24 h) and dose (0, 1, 2, 3, 4 mmol/kg) dependency. The induction of LPO by 2-NP was significantly reduced in lung and kidney when melatonin (2.5, 5 or 10 mg/kg) was given prior to 2-NP administration. The elevation in serum SDH caused by 2-NP was also reduced when melatonin was given. These findings show that 2-NP induces LPO and that pharmacological levels of melatonin can reduce the toxicity of this hepatocarcinogen.

Regulation of alphaIIb beta3 function in human B lymphocytes

We studied the function of the platelet integrin alphaIIb beta3 using a B lymphocyte model in which alphaIIb beta3 can be induced to interact with fibrinogen using phorbol myristate acetate (PMA). To determine whether a G protein-coupled receptor could also activate alphaIIb beta3 in lymphocytes, we coexpressed the human formyl peptide receptor (fPR) and alphaIIb beta3, finding that the fPR agonist formyl Met-Leu-Phe (fMLP)-stimulated lymphocyte adherence to immobilized fibrinogen and binding of soluble fibrinogen to the lymphocyte surface. The response to fMLP, but not PMA, was abrogated by pertussis toxin, indicating that the fPR was coupled to the G-protein Galphai, whereas the protein kinase C inhibitor bisindolylmaleimide I inhibited the response to both fMLP and PMA, indicating that signaling from the fPR included protein kinase C. On the other hand, the tyrosine kinase inhibitor genistein, the Syk inhibitor piceatannol, and the RhoA inhibitor C3 exoenzyme had no effect, implying that neither tyrosine phosphorylation nor the GTPase RhoA were involved. Furthermore, whereas micromolar concentrations of cytochalasin D inhibited the PMA-stimulated interaction of alphaIIb beta3 with fibrinogen, nanomolar concentrations actually induced fibrinogen binding to unstimulated cells. Our studies demonstrate that alphaIIb beta3 expressed in B lymphocytes can be activated by a physiologic agonist and outline an activating pathway that includes Galphai, protein kinase C, and the actin cytoskeleton.

Localization of pNT22 70 kDa heat shock cognate-like protein in the plasma membrane

It has been argued that 70 kDa heat shock cognate (hsc73)-like molecules may be expressed on the surface of certain cells, but direct evidence of this has yet to be found. To clarify whether this molecule belongs to hsc73 itself, the membrane protein fraction of Daudi cells was isolated by Triton X-114 phase separation and the reactivity of this membrane protein fraction was assessed with monoclonal antibodies (mAbs) which react with 70 kDa heat shock protein (hsp) family, i.e., NT22, A15 and 3A3. In western blotting analysis, mAb NT22-defined protein (pNT22) was clearly detected as a membrane protein of Daudi cells with an approximate molecular size of 70 kDa, whereas pNT22 was not recognized by anti-cytoplasmic hsc73/hsp72 mAbs A15 or 3A3. By using deleted recombinant hsc73 proteins, it was determined that mAb NT22 recognizes the N-terminal 350-372 amino acid stretches of the hsc73 protein. mAb NT22 also reacted with the cell surface protein of Daudi cells in FACS analysis. Taken together, our present data strongly suggest that pNT22 may be a novel hsc73-like protein that is localized in the plasma membrane.

[Immunohistochemical study on the distribution and coexistence of SP, VIP and NPY in the rat submandibular gland]

The distribution and coexistence of SP, VIP and NPY in the submandibur gland of rat have been studied with immunohistochemical ABC methods. The results indicated that SP, VIP and NPY-IR nerve fibers were presented as varicose and linear profiles, which mainly travelled around acini, duct and blood vessels. The ganglion cells in submandibular gland showed SP, VIP and NPY-IR all positive immunocytochemically. The findings indicated that the neuropeptides were coexisted in the same neuron body and might play the role of regulation of the secretary activity and effective blood supply.

[Clinical analysis of 39 cases of hepatitis E in pregnancy]

OBJECTIVE

To introduce clinical manifestations and treatment of hepatitis E in pregnancy.

METHODS

Thirty-nine cases of hepatitis E in pregnancy, were analysed from June. 1992 to Jun. 1994, retrospectively on its epidemiologic characteristics, clinical manifestations and prognosis.

RESULTS

The prognosis of sporadic cases of hepatitis E in pregnancy was good and its main complications were premature rupture of membranes, uterine inertia and fetal distress.

CONCLUSIONS

Sporadic case is the main form of hepatitis E in pregnancy in Beijing. Active treatment and intensive monitoring would improve its prognosis.

Effect of cytoplasmic domain mutations on the agonist-stimulated ligand binding activity of the platelet integrin alphaIIbbeta3

Function of the platelet integrin alphaIIbbeta3 is regulated by agonist-generated signals interacting with its cytoplasmic tails. When alphaIIbbeta3 is expressed in Epstein-Barr virus-transformed B lymphocytes, stimulation of the cells with phorbol 12-myristate 13-acetate results in alphaIIbbeta3-mediated lymphocyte adherence to immobilized fibrinogen, as well as soluble fibrinogen binding to alphaIIbbeta3, indicating that agonists increase the affinity of alphaIIbbeta3 for fibrinogen in these cells. To address the contribution of the alphaIIb and beta3 cytoplasmic tails to this process, we mutated each tail and expressed the mutants in B lymphocytes. Truncation of the alphaIIb tail did not impair unstimulated or stimulated lymphocyte adherence to fibrinogen, regardless whether the truncation was proximal or distal to the conserved GFFKR sequence. However, deleting GFFKR or replacing it with alanines markedly reduced alphaIIbbeta3 expression due to impaired intracellular assembly of alphaIIbbeta3 heterodimers, probably due to a mutation-induced change in the conformation of alphaIIb. Introducing beta3 mutations known to impair alphaIIbbeta3 function in platelets into the cytoplasmic tail of beta3 in lymphocytes also impaired alphaIIbbeta3 function in these cells. These studies demonstrate that the cytoplasmic tail of alphaIIb is not required for alphaIIbbeta3 function in lymphocytes, although the presence of GFFKR in the alphaIIb tail is required for alphaIIb to interact with beta3. Additionally, they indicate that signals interacting with the beta3 cytoplasmic tail are responsible for the ability of agonists to stimulate alphaIIbbeta3 function.

[Dynamic change of beta 2-microglobulin in hemodialysis]

In order to study the dynamic clearance of total beta 2-microglobulin in the body, two-compartment theory and perturbation solution were applied in our study. Based on the rate of formation of beta 2-microglobulin in the body and the mode of transmission and mass transfer resistance of solute, the concept of week clearance index of beta 2-microglobulin (R value) was suggested. Its theoretical value is more than 40%. Thirty-two patients undergoing dialysis with high-efficiency dialyzer were studied and data were processed in a computer. The results showed that when R value was more than 40%, the clinical manifestation of amyloidosis carpal tunnel syndrome induced by increase of beta 2-microglobulin was alleviated obviously. It makes up for the limitation of KT/V or TA Curea that were used only to estimate adequate dialysis of small molecules. It is shown that the concept of week cleacance index of beta 2-microglobulin improves the estimation of adequate dialysis.

Inhibition of natural killer cell cytotoxicity by cell growth-related molecules

Certain MHC class I molecules on target cells are known to inhibit the cytotoxic action of NK cells. By using monoclonal antibody (mAb) Cho-1, we have found inhibitory non-MHC class I cell surface molecules that are noncovalently-associated with 200 kDa and 40 kDa antigens. Poly I-C-induced rat NK cells were not cytotoxic to rat fetus-derived fibroblast WFB cell line. In contrast, NK cells were cytotoxic to H-ras oncogene-induced transformants of WFB, W14 and W31. FACS analysis indicated that mAb Cho-1 reacts with WFB, but not with W14 and W31 cells. Thus, this antigen may disappear concomitantly with cell growth and transformation. Cho-1 antigens were also expressed on other NK-resistant lines, such as mouse BALB3T3 fibroblast, EL-4 lymphoma and human fibroblast HEPM. However, they were not expressed on NK-sensitive mouse YAC-1 and H-ras transformant (Brash) of BALB3T3 cells. Furthermore, treatment of target cells with IFN-gamma clearly induced the cell surface expression of Cho-1 antigens, and conferred a resistance to NK cytolysis on target cells. These data strongly suggest that Cho-1 antigen expression may correlate with target cell susceptibility to NK cells. Indeed, treatment of NK-resistant WFB as well as HEPM cells with F(ab')2 fragments of mAb Cho-1 resulted in the acquisition of susceptibility to NK cytolysis. Cho-1 antigens may be novel molecules that regulate the NK resistance of cells.

Finite element analysis and experimental studies on the thickness resonance of piezocomposite transducers

Finite element method (FEA) has been used to calculate the thickness resonance frequency and electromechanical coupling coefficient kt for 2-2 piezocomposite transducers. The results are compared with that of the effective medium theory and also verified by experiments. It is shown that the predicted resonance frequencies from the effective medium theory and the unit cell modeling using FEA deviate from the experimental observations for composite systems with a ceramic aspect ratio (width/length) more than 0.4. For such systems, full size FEA modeling is required which can provide accurate predictions of the resonance frequency and thickness coupling constant kt.