Inhibition of IL-10-induced STAT3 activation by 15-deoxy-Δ12,14-prostaglandin J2

OBJECTIVES

15-Deoxy-Delta12,14-prostaglandin J2 (15d-PGJ2) is a natural ligand that activates the peroxisome proliferator-activated receptor (PPAR)-gamma, a member of the nuclear receptor family implicated in the regulation of lipid metabolism and adipocyte differentiation. Recent data have shown that 15d-PGJ2 exerts anti-inflammatory action via inhibition of the interferon gamma (IFN-gamma)-induced Jak-STAT signalling pathway. The anti-inflammatory effect of IL-10 is mediated via activated STAT3 (signal transducer and activator of transcription 3). In this study, we investigated whether 15d-PGJ2 inhibit IL-10-induced STAT activation.

METHODS

We used western blotting, flow cytometric analysis and a real-time polymerase chain reaction.

RESULTS

15d-PGJ2 blocked IL-10-induced STAT1 and STAT3 activation in primary human monocytes, macrophages and THP-1 cells. Inhibition was not specific for IL-10, as induction of STAT activation by IFN-gamma and IL-6 was also inhibited by 15d-PGJ2. Inhibition of IL-10 signalling was induced within 1 h after pretreatment of 15d-PGJ2. Other PPARgamma agonists, such as troglitazone, did not inhibit IL-10 signalling. Treatment with GW9662, a specific PPARgamma antagonist, had no effect on 15d-PGJ2-mediated inhibition of IL-10 signalling even at higher concentrations (50 microM), indicating that 15d-PGJ2 affects the IL-10-induced Jak-STAT signalling pathway via an PPARgamma-independent mechanism. Actinomycin D had no effect on 15d-PGJ2-mediated inhibition of IL-10 signalling, indicating that inhibition of IL-10 signalling occurs independently of de novo gene expression. Also, inhibitors of extracellular signal-regulated kinase (ERKs) (PD98059), p38 MAPK (mitogen-activated protein kinase) (SB203580) and protein kinase C (PKC) (GF109203X, calphostin C) had no effect on 15d-PGJ2-mediated inhibition of IL-10 signalling. These results show that MAPKs and PKC are not involved in the inhibition of IL-10 signalling.

CONCLUSIONS

We showed that 15d-PGJ2 non-specifically inhibits STAT signalling of the anti-inflammatory cytokine IL-10 as well as the proinflammatory cytokine IFN-gamma. These findings indicate the possibility that 15d-PGJ2 can have adverse effects in the management of diseases in which IL-10 plays a critical role in the suppression of inflammation.

Platelet-derived growth factor-AA increases IL-1beta and IL-8 expression and activates NF-kappaB in rheumatoid fibroblast-like synoviocytes

The effect of platelet-derived growth factor (PDGF)-AA on the inflammation in rheumatoid arthritis (RA) and osteoarthritis (OA) was investigated using cultured fibroblast-like synoviocytes (FLS) obtained from RA and OA patients as well as control nonarthritic (NA) individuals. PDGF-AA increased the mRNA and protein expressions of proinflammatory cytokines, interleukin (IL)-1beta and IL-8 in RA FLS. Biological activity of IL-1 in the culture supernatant of RA FLS was also increased by PDGF-AA stimulation. Interestingly, PDGF-AA synergized with tumour necrosis factor (TNF)-alpha to upregulate the protein expressions of IL-1beta and IL-8. PDGF-induced enhancement of the IL-1beta and IL-8 mRNA expressions was also observed in OA FLS. However, the expression of these proinflammatory cytokines in NA FLS did not change by PDGF treatment, suggesting that the inflammatory condition might have modified the biological effects of PDGF. In accordance with the enhanced expression of inflammatory cytokines, the activity of nuclear factor kappaB was also induced in response to PDGF-AA in RA FLS. These results suggest that PDGF-AA plays an important role in the progression of RA inflammation, and inhibiting PDGF activity may be useful for the effective RA treatment.

Remote hot spots mediate protein substrate recognition for the Cdc25 phosphatase

Cdc25B is a phosphatase that catalyzes the dephosphorylation and activation of the cyclin-dependent kinases, thus driving cell cycle progression. We have identified two residues, R488 and Y497, located >20 A from the active site, that mediate protein substrate recognition without affecting activity toward small-molecule substrates. Injection of Cdc25B wild-type but not the R488L or Y497A variants induces germinal vesicle breakdown and cyclin-dependent kinase activation in Xenopus oocytes. The conditional knockout of the cdc25 homolog (mih1) in Saccharomyces cerevisiae can be complemented by the wild type but not by the hot spot variants, indicating that protein substrate recognition by the Cdc25 phosphatases is an essential and evolutionarily conserved feature.

Various conditioning methods for root canals influencing the tensile strength of titanium posts

Conditioning the root canal is frequently advised to achieve high post-retention when resin composite luting cements are used. However, manufacturers' instructions for this purpose differ widely from one another. The aim of this study was to compare the tensile bond strengths of passive, tapered, titanium root posts that were luted with four different resin composite cements (Compolute Aplicap, Flexi-Flow cem, Panavia 21 EX, Twinlook) in the root canals at three conditions, namely (i) no conditioning, (ii) etching with 37% phosphoric acid, and (iii) etching + bonding agent application. Panavia 21 EX was further tested after using the primer for the post-surface according to the manufacturer's recommendations. The posts luted with zinc phosphate cement (Tenet) acted as the control group. Following endodontic preparation of 140 intact anterior teeth with hand instruments, the post-spaces were prepared using the opening drills of the corresponding size of the posts. The samples were first stored in water at 37 degrees C for 24 h and then thermocycled (5000 cycles, 5-55 degrees C, 30 s). The tensile strength values were measured with the universal testing machine at a crosshead speed of 0.5 mm min(-1). The data were analysed statistically using anova and corrected with Scheffé test due to the significance levels (P < 0.05). The tensile bond strengths of the titanium posts after luting with various cements and thermocycling were affected by the conditioning systems used for the root canals. Tensile bond strengths were the highest with Flexi-Flow (475 +/- 78 N) followed in descending order by Panavia 21 EX (442 +/- 97 N), Twinlook (430 +/- 78 N) and Compolute Aplicap (352 +/- 76 N) after conditioning the root canal. The use of primer on the post improved the tensile bond strength compared with the non-conditioned group for the Panavia 21 EX group (375 +/- 77 N) (P < 0.001). Tensile bond strengths obtained after luting the posts with zinc phosphate cement (414 +/- 102 N) were not significantly different (P < 0.05) than those of resin composite cements. Although the importance of conditioning the root canal was evident for Panavia 21 EX, it was not the case for the other luting cements tested.

Common and differential mechanisms of gonadotropin receptors

The gonadotropin receptors are G-protein-coupled receptors with unique structural and functional features, consisting of two halves. The N-terminal extracellular half (exodomain) binds the hormones, whereas the C-terminal membrane-associated half (endodomain) is responsible for receptor activation. In this review, the novel ternary interactions, contact points and mutual modulations among the exodomain, endodomain and hormone for hormone binding and signal generation are described based on the latest observations. This discussion is contrary to the yiew that the exodomain and endodomain are independent, at least functionally, and provides new insights into the receptor mechanisms for the gonadotropins and other G-protein-coupled receptors.

Polymorphsims of CTLA-4 exon 1 +49, CTLA-4 promoter -318 and Fas promoter -670 in spondyloarthropathies

The aim of the study was to investigate a possible association between the CTLA-4 exon 1 +49, CTLA-4 promoter -318 and Fas promoter -670 and spondyloarthropathies (SpA). Polymerase chain reaction of genomic DNA-restriction fragment length polymorphism was used to determine genotypes of the CTLA-4 exon 1 +49, CTLA-4 promoter -318 and Fas promoter -670 in 54 SpA patients, 84 healthy control subjects and 87 bronchial asthma patients as disease controls. There were no significant differences in the genotype and allele frequencies of the CTLA-4 exon 1, promoter and Fas promoter genes among SpA, asthma patients and controls. No significant differences were found in age at onset, sex, disease duration, history of enthesopathy, peripheral arthritis and uveitis, Schober test, chest expansion, white blood cell count, C-reactive protein and erythrocyte sedimentation rate among patients with SpA according to the CTLA-4 exon 1, CTLA-4 promoter and Fas promoter polymorphisms. We found no association between the polymorphisms of the CTLA-4 exon 1 +49, CTLA-4 promoter -318 and Fas promoter -670 genes and SpA. However, further studies are required to discover the possible contribution of the polymorphisms of the CTLA-4 and Fas to the pathogenesis of SpA.

Polymorphisms of the CTLA-4 exon 1 and promoter gene in systemic lupus erythematosus

The objective of this study was to determine whether the polymorphisms of the CTLA-4 exon 1 (+49) and promoter (-318) are associated with susceptibility to systemic lupus erythematosus (SLE) and its clinical features. Polymerase chain reaction of genomic DNA-restriction fragment length polymorphism was used to determine genotypes of the CTLA-4 exon 1 (+49) and promoter (-318) in 80 SLE patients and 86 healthy control subjects. The genotype distribution of the CTLA-4 exon 1 (+49) differed between SLE patients and controls (chi2 = 6.74, 2 degrees of freedom (d.f.), P = 0.03). The CTLA-4 AG genotype occurred more frequently in patients with SLE (46.3% vs 33.7% controls). On the other hand, the CTLA-4 AA genotype as well as the CTLA-4 GG genotype was less frequent among SLE patients than among control subjects (1.3% vs 9.3% and 52.5% vs 57.0%, respectively). The genotype distribution of the CTLA-4 promoter (-318) differed between SLE patients and control subjects (CT, TT, CC; genotypes 27.5%, 0%, 72.5% vs 16.3%, 4.7%, 79.1% controls respectively, chi2 = 6.36, 2 d.f., P = 0.04). However, Fischer's exact or chi2 P-values for each genotypes of the CTLA-4 exon 1 (+49) and promoter (-318) between SLE and control group were > 0.05. Clinically, in the lupus patients there was no significant difference according to the CTLA-4 polymorphisms. In conclusion, no correlation was found between CTLA-4 exon 1 (+49) and promoter (-318) polymorphisms and SLE in our study.

Increased expression of pro-inflammatory cytokines and metalloproteinase-1 by TGF-beta1 in synovial fibroblasts from rheumatoid arthritis and normal individuals

Transforming growth factor (TGF)-beta1 is expressed abundantly in the rheumatoid synovium. In this study, the inflammatory effect of TGF-beta1 in rheumatoid arthritis (RA) was investigated using cultured fibroblast-like synoviocytes (FLS) from RA and osteoarthritis (OA) patients, as well as non-arthritic individuals. mRNA expressions of IL-1beta, tumour necrosis factor (TNF)-alpha, IL-8, macrophage inflammatory protein (MIP)-1alpha and metalloproteinase (MMP)-1 were increased in RA and OA FLS by TGF-beta1 treatment, but not in non-arthritic FLS. Enhanced protein expression of IL-1beta, IL-8 and MMP-1 was also observed in RA FLS. Moreover, TGF-beta1 showed a synergistic effect in increasing protein expression of IL-1beta and matrix metalloproteinase (MMP)-1 with TNFalpha and IL-1beta, respectively. Biological activity of IL-1 determined by mouse thymocyte proliferation assay was also enhanced by 50% in response to TGF-beta1 in the culture supernatant of RA FLS. DNA binding activities of nuclear factor (NF)-kappaB and activator protein (AP)-1 were shown to increase by TGF-beta1 as well. These results suggest that TGF-beta1 contributes for the progression of inflammation and joint destruction in RA, and this effect is specific for the arthritic synovial fibroblasts.

p53 codon 72 polymorphism and rheumatoid arthritis

OBJECTIVE

To investigate whether the p53 codon 72 polymorphism is associated with susceptibility to rheumatoid arthritis (RA) and its clinical features.

METHODS

A polymerase chain reaction of genomic DNA-restriction fragment length polymorphism was used to determine genotypes of the p53 codon 72 in 114 patients with RA and 114 healthy controls. Clinical/serological manifestations were analyzed in each patient and correlated with the genotypes.

RESULTS

The genotype distribution of the p53 codon 72 did not differ between patients with RA and controls (Arg/Arg, Arg/Pro, Pro/Pro genotypes 38, 58, 18 vs 37, 60, 17 controls, respectively; chi-square = 0.08, 2 df, p = 0.96). No significant difference was found in allele frequencies between the groups. Clinically there was no significant difference in age at onset, functional class, physician's global assessment, ESR, CRP, RF titer, extraarticular and cervical spine involvement, frequencies of joint operation, and admission in RA patients according to the p53 codon 72 genotypes. However, the number of patients within each group was extremely small, for example only 5 patients with cervical spine involvement. No firm conclusions could safely be reached about clinical manifestations from this study.

CONCLUSION

No association was found between the p53 codon 72 polymorphism and RA. Studies are needed to clarify the role of the p53 polymorphism in the pathogenesis of RA.

Effects of peroxisome proliferator-activated receptor-gamma (PPAR-gamma) on the expression of inflammatory cytokines and apoptosis induction in rheumatoid synovial fibroblasts and monocytes

This study was performed to investigate whether peroxisome proliterator-activated receptor-gamma (PPAR-gamma) exerted an anti-inflammatory effect on rheumatoid synovial cells and inhibited dysregulated proliferation. The expression of PPAR-gamma mRNA in cultured human synoviocytes and THP-1 cells was analysed by RT-PCR. PPAR-gamma was expressed in normal, osteoarthritis (OA), rheumatoid arthritis (RA) synovial cells as well as a human monocytic cell line, THP-1. In RA and OA synoviocytes, the induction of inflammatory cytokine mRNA expression such as TNF-alpha and IL-1beta was significantly inhibited by the natural PPAR-gamma agonist, 15 deoxy-Delta(12,14)prostaglandin J(2)(15d-PGJ(2)). The effect of PPAR-gamma on the nuclear factor (NF)-kappaB activity was tested by electrophoretic mobility shift assay (EMSA). Both troglitazone and 15d-PGJ(2)markedly inhibited TNF-alpha-induced NF-kappaB activation at 30 microM. However, PPAR-gamma agonist neither reduced proliferation nor induced apoptosis in RA synoviocytes when measured by XTT assay and fluorescence activated cell sorter (FACS) analysis. In contrast, it induced apoptosis in a dose-dependent manner in THP-1 cells and augmented TNF-related apoptosis-inducing ligand (TRAIL)-induced apoptosis as well. In conclusion, these data demonstrate that PPAR-gamma is expressed in human synoviocytes and THP-1 cells, and the PPAR-gamma activation inhibits expression of inflammatory cytokines in RA synoviocytes. Furthermore, PPAR-gamma activation induces apoptosis by itself and augments TRAIL/Apo2L-induced apoptosis in THP-1 cells. These results suggest that PPAR-gamma agonists may provide a new therapeutic approach for RA.

Fas promoter -670 polymorphism is associated with development of anti-RNP antibodies in systemic lupus erythematosus

OBJECTIVE

To evaluate whether the polymorphism of Fas promoter -670 is associated with susceptibility to systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) and their clinical features.

METHODS

A polymerase chain reaction of a genomic DNA-restriction fragment length polymorphism was used to determine genotypes of the Fas promoter -670 in 87 patients with SLE, 87 with RA, and 87 healthy controls. A second cohort of SLE patients (n = 85) was included. Clinical manifestations were analyzed in each patient and correlated with the genotypes.

RESULTS

The genotype distribution of the Fas promoter -670 did not differ between patients with SLE and control subjects (AA, GA, GG genotypes 31, 54, 15% vs 30, 55, 15% controls, respectively; chi-squared = 0.03, 2 df, p = 0.99) and between RA patients and controls (AA, GA, GG genotypes 38, 44, 18% vs 30, 55, 15% controls, respectively; chi-squared = 2.30, 2 df, p = 0.32). Regarding the clinical status of lupus patients according to Fas promoter -670 genotypes, there was no significant difference in age at onset, anti-dsDNA titer, C3, C4 level, renal involvement, number of American College of Rheumatology (ACR) criteria met, SLE Disease Activity Index, SLE International Collaborating Clinics/ACR Damage Index, or autoantibody profiles. However, the frequency of anti-RNP antibody was significantly different in the AA, GA, and GG groups (71, 25, 30%; chi-squared = 13.29, 2 df, p = 0.001). To confirm this finding, the Fas promoter -670 genotype was examined in a second cohort of SLE patients (n = 85). The result in the second cohort replicated the association shown in the first. In patients with RA, there was no significant difference in clinical and laboratory findings according to the Fas promoter -670 genotypes.

CONCLUSION

Our data suggest that the Fas promoter -670 polymorphism is associated with development of anti-RNP antibodies in SLE.

Monitoring and modeling of disinfection by-products (DBPs)

In the United States, the newly promulgated disinfectant/disinfection by-product (D/DBP) regulations force water treatment utilities to be more concerned with finished and distributed water qualities. In this study, monitoring of DBP formation was conducted from three French water treatment plants trying to assess DBP variations through time and space. Compared to the in-plant total trihalomethanes (TTHM) levels, TTHM levels in the distribution system increased from less than 150% to more than 300%. Significant variations for TTHM and bromate (BrO3-) levels throughout the seasons were also observed; generally higher levels in the summer and lower levels in the winter. Combining chemical DBP models (empirical power functional models) and hydraulic simulations, DBPs including TTHM and BrO3- were successfully simulated from the full-scale monitoring data, indicating that empirical DBP model can be a potential tool to access DBP formation in actual plants. This study also provides the protocols to assess DBP simulations in the water treatment systems.

Sequence variations of hepatitis B virus promoter regions in persistently infected patients

The HBV in the sera of two chronic active hepatitis patients were analyzed for the promoter sequence heterogeneity. In most cases, the proportion of any particular clone in the total viral populations was less than 50%, showing high mutation rates. In contrast, promoter sequences of HBV from asymptomatic carriers revealed only a few point mutations with no deletions. HBV in chronic patient harbored variants with multiple mutations throughout promoters including 1762 (A-to-T), 1764 (G-to-A) double mutation in C promoter and deletions near CCAAT site in S promoter. Unlike other three promoter regions, C, pre-S1 and S, of HBV which revealed a high level of sequence heterogeneity, the X promoter region (from nt985 to 1430) showed little sequence heterogeneity within a patient. However, the predominant viral clones in two patients were quite different from each other. In addition to mutations in promoter regions, a deletion mutation in the translation start codon was also found in pre-S1 gene. The results in this report indicate that the mutation rates are not the same in all four promoters and that one of the strategies for maintaining persistent infection could be through mutations in viral promoters which then impair the balance of viral gene expressions.

Analysis of Ig kappa light chain gene variable regions expressed in the rheumatoid synovial B cells

Sequence analysis of antibody variable (V) regions can provide an insight regarding whether B cells have gone through an antigen-driven process of affinity maturation. In this study, we analyzed 16 V-regions of immunoglobulin (Ig) kappa light chain genes obtained from a cDNA library of a rheumatoid arthritis (RA) synovial tissue. A salient feature of our results is the high frequency utilization of germline V kappa I family genes, especially the O2/O12 gene (38%). All kappa V-regions showed extensive somatic hypermutation with 5.4% of an average mutation rate. Replacement to silent mutation (R/S) ratio in the complementarity determining region (CDR) was > 2.9 in 12 out of 16 clones, indicating that the majority of the RA synovial B cells had undergone affinity maturation. However, the four other clones showed R/S ratios of < 2.9 in the CDR despite a high mutation rate. In contrast to the previous reports, long CDR3 was not a characteristic feature of these clones. In summary, these data show the high frequency utilization of the germline O2/O12 gene and a high rate of mutation with an evidence of antigen selection in most of the Ig kappa genes expressed in the RA synovium.

Purification of soluble beta-glucan with immune-enhancing activity from the cell wall of yeast

Beta-glucan, one of the major cell wall components of Saccharomyces cerevisiae, has been found to enhance immune functions, especially by activating macrophages. However, a major obstacle to the clinical application of beta-(1-->3)-glucan is its low solubility in aqueous media. In this study, soluble beta-glucan, free of mannoprotein, was prepared, and its effects on TNF-alpha secretion and phagocytosis by macrophages were evaluated. Beta-glucan was first rendered soluble from the yeast cell wall by alkaline extraction (glucan-p1). The extract contained 2.8% of protein which was subsequently removed by successive DEAE-cellulose and ConA chromatography. Beta-glucan thus prepared was completely free of mannoprotein and was soluble at neutral pH (glucan-p3). The effects of beta-glucan on phagocytosis and TNF-alpha release activity were investigated. While glucan-p1 moderately induced TNF-alpha secretion at 200 microg/ml (550 pg of TNF-alpha/5 x 10(5) cells), glucan-p3 markedly stimulated macrophages at 200 microg/ml (2,860 pg of TNF-alpha/5 x 10(5) cells). Furthermore, glucan-p3 stimulated phagocytosis about 20% more than glucan-p1 did. In conclusion, we purified water-soluble beta-glucan which was completely devoid of mannoprotein and effectively stimulated the macrophage function, enabling it to be used as an intravenous injection for sepsis.

Unusual patterns of hepatic steatosis caused by the local effect of insulin revealed on chemical shift MR imaging

OBJECTIVE

We reveal the chemical shift MR findings of unusual patterns of hepatic steatosis caused by the local effect of insulin.

CONCLUSION

Unusual patterns of hepatic steatosis can be seen on MR imaging. Such patterns result from localized high concentrations of insulin. A rim of hepatic steatosis surrounding insulinoma metastases and a subcapsular distribution of hepatic steatosis in patients with diabetes treated with peritoneal dialysis are two such patterns that can be revealed on chemical shift imaging.

Characterization of muscles associated with the articular membrane in the dorsal surface of the crayfish abdomen

The anatomy, physiology, and biochemistry of the dorsal membrane muscle (DMA) and the superficial extensor muscle accessory head (SEAcc) in the abdomen of the crayfish, Procambarus clarkii and lobster, Homarus americanus, are reported. These muscles have not been previously characterized physiologically or biochemically. The anatomy was originally described by Pilgrim and Wiersma (1963. J Morph 113:453-587). The arrangement of these muscles varies depending on the abdominal segment. The function of the dorsal membrane muscle is to retract the thin articulating membrane joining the cuticular segments so that the dorsal membrane does not evert during extension of the abdomen. Consequently, the articular membrane does not protrude, and thus potential damage to the membrane is minimized. Examination of nerve terminal morphology revealed strings of varicosities, usually only associated with tonic terminals. The electrophysiological data indicate that there are at least four tonic excitatory and one inhibitory motor neuron innervating these muscles. Facilitation indices and fatigue-resistance indicate physiologically the tonic nature of innervation. Anti-GABA antibodies demonstrate the anatomical presence of an inhibitor motor neuron. The SDS electrophoretic analysis of myofibrillar proteins and Western blots of key protein isoforms for these muscles in crayfish and lobsters also indicate that the DMA and SEAcc muscles are tonic phenotype. J. Exp. Zool. 287:353-377, 2000.

Depletion of intracellular zinc induces macromolecule synthesis- and caspase-dependent apoptosis of cultured retinal cells

Although zinc deficiency may contribute to age-related macular degeneration (ARMD), the pathogenic mechanism is as yet uncertain. In light of evidence that cellular zinc depletion induces apoptosis in cortical neurons and thymocytes, in the present study, we examined the possibility that the same phenomenon occurs also in retinal cells. Exposure of primary retinal cell cultures to 1-3 microM of a cell membrane-permeant zinc chelator TPEN for 24 h induced concentration-dependent death of neurons, photoreceptor cells, and astrocytes. Addition of zinc or copper reversed TPEN toxicity to all cell components, indicating the particular involvement of zinc chelation in cell death. Consistent with apoptosis, oligonucleosomal DNA fragmentation and chromatin condensation accompanied, and the protein synthesis inhibitor cycloheximide blocked the TPEN-induced retinal cell death. During TPEN-induced retinal cell apoptosis, cleavage/activation of procaspase-1, but little of procaspase-3, was observed. Consistent with this finding, a broad-spectrum caspase inhibitor (zVAD-fmk) was significantly more protective than a caspase-3-selective inhibitor (DEVD-fmk). The present study has demonstrated that depletion of intracellular zinc is sufficient to induce macromolecule synthesis- and caspase-dependent apoptosis of cultured retinal cells. In light of the possibility that zinc depletion may contribute to the pathogenesis of ARMD, the current culture model may be a useful tool for the investigation of the mechanism of zinc depletion-induced retinal cell death.

High level activation of vitamin B1 biosynthesis genes in haustoria of the rust fungus Uromyces fabae

In the rust fungus Uromyces fabae, the transition from the early stages of host plant invasion toward parasitic growth is accompanied by the activation of many genes (PIGs = in planta induced genes). Two of them, PIG1 (= THI1) and PIG4 (= THI2), were found to be highly transcribed in haustoria, and are homologous to genes involved in thiamine (vitamin B1) biosynthesis in yeast. Their functional identity was confirmed by complementation of Schizosaccharomyces pombe thiamine auxotrophic thi3 (nmt1) and thi2 (nmt2) mutants, respectively. In contrast to thiamine biosynthesis genes of other fungi that are completely suppressed by thiamine, THI1 and THI2 expression was not affected by the addition of thiamine to rust hyphae grown either in vitro or in planta. Immunoblot analysis revealed decreasing amounts of THI1p in extracts from spores, germlings, and in vitro-grown infection structures with increasing time after inoculation. Immunofluorescence microscopy of rust-infected leaves detected high concentrations of THI1p in haustoria, and only low amounts in intercellular hyphae. In the sporulating mycelium, THI1p was found in the basal hyphae of the uredia, but not in the pedicels and only at very low levels in uredospores. These data indicate that the haustorium is an essential structure of the biotrophic rust mycelium not only for nutrient uptake but also for the biosynthesis of metabolites such as thiamine.

Induction of G(1) cell cycle arrest and p27(KIP1) increase by panaxydol isolated from Panax ginseng

Polyacetylenic compounds of Panax ginseng roots have been shown to inhibit growth of several human malignant tumor cell lines. Panaxydol is known to be one of the cytotoxic polyacetylenic compounds of P. ginseng. In this study, we first showed that panaxydol decreased markedly the proliferation, and to a lesser extent, the number of cells in a human melanoma cell line, SK-MEL-1. Next, the effect of panaxydol on cell cycle progression and its mechanism of action were investigated. Cell cycle analysis revealed that panaxydol inhibited cell cycle progression of a human malignant melanoma cell line, SK-MEL-1, at G(1)-S transition. At the same time, panaxydol increased the protein expression of p27(KIP1) as early as 1 hr after treatment. Cyclin-dependent kinase 2 (Cdk2) activity was decreased in a dose-dependent manner after 24 hr of panaxydol treatment. Protein levels of p21(WAF1), p16(INK4a), p53, pRb (retinoblastoma protein), and E2F-1 were not changed. It was also found that cycloheximide reversed the growth inhibition induced by panaxydol and partially abrogated the increase in p27(KIP1) expression. These results indicate that panaxydol induces G(1) cell cycle arrest by decreasing Cdk2 activity and up-regulating p27(KIP1) protein expression.

Regulation of bcl-2 family in hydrogen peroxide-induced apoptosis in human leukemia HL-60 cells

Numerous types of cells have been shown to undergo apoptosis when exposed to oxidant agent such as hydrogen peroxide. In order to understand the functional relationship between the anti- and pro-apoptotic regulatory proteins in the cells under oxidant stress, we have studied the level of expression of apoptosis regulatory proteins, bcl-2 and bax, in human leukemia HL-60 cells. The exposure of HL-60 cells to different concentrations of H2O2 for 6 h resulted in a typical apoptosis of the cells as characterized by flow cytometry, cell cycle analysis, and DNA fragmantation. There was a block in G1 to S transition and apoptotic cells were mainly derived from S and G2 cells. Kinetic study demonstrated that the levels of both bcl-2-mRNA and -protein expression were decreased with the progression of cellular apoptosis whereas the level of bax-mRNA was unchanged but the expressed bax-protein was not detectable. Cycloheximide, a nonspecific translation inhibitor, did not prevent the hydrogen peroxide-mediated apoptosis in HL-60 cells. These results suggest that the regulation of bcl-2, but not of bax are important factor in the oxidative stress-induced apoptosis in HL-60 cells.

Cross-linking of CD4 induces cytoskeletal association of CD4 and p56lck

A membrane glycoprotein CD4 functions as a co-receptor of a T lymphocyte. The co-receptor function has been attributed to a protein tyrosine kinase, p56lck, which is activated upon CD4 binding to MHC molecule. In this study, we present evidences that one of the pathways through which CD4 transmits its signal is cytoskeleton association of p56lck tyrosine kinase as well as CD4 itself. Cytoskeletal association of both proteins is inhibited by a tyrosine kinase inhibitor, genistein, indicating that tyrosine protein kinase activation is important for cytoskeletal association of CD4 and p56lck. Cytoskeletal association of these proteins by CD4 cross-linking is not affected by inhibitors of protein kinase C nor PI3-kinase. Taken together, these results suggest that CD4 cross-linking activates a tyrosine kinase which then induces the simultaneous association of CD4 and p56lck with cytoskeleton.

Reducing scatter radiation to the contralateral breast with a mobile, conformal shield during breast cancer radiotherapy

During a standard course of breast radiotherapy, the contralateral breast generally receives approximately 2.5 to 6.0 Gy of scattered radiation. Although most studies have not found an overall increase in metachronous contralateral breast cancers in patients undergoing radiotherapy, a cohort of younger women may be genetically more susceptible to radiation-induced breast cancers and may thus be adversely affected by the scattered radiation. We are attempting to develop a simple, convenient, effective mechanism for minimizing the scattered radiation to the contralateral breast during the process of clinical breast radiotherapy. We therefore designed a conformal, platform-based breast shield consisting of 2.5 cm of molded lead in a mobile counterweighted polystyrene casing. This shield was intended to serve as a physical barrier to prevent both low and high energy scattered photons from the medial and lateral tangential fields. We conducted a prospective trial of 20 women, each woman serving as her own control. Each woman received breast radiotherapy with and without shield, and an array of thermoluminescent dosimeters was positioned across the contralateral breast to evaluate the in vivo dosimetry and the impact of the breast shield on surface absorption of scattered radiation. We found that the use of the breast shield reduced the median dose of scattered radiation by approximately 60% (p < 0.0001). This represented a median dose reduction of approximately 300 cGy at the nipple. The shield was easily positioned and added < 1 min to daily setup time. We conclude that the use of this sort of surface barrier shielding technique was feasible, effective, and practical for clinical use. The degree of scatter reduction accomplished through the use of this breast shield may be biologically significant, especially for those patients with biologic or epidemiologic risk factors that may predispose them to the development of radiogenic breast cancers.

An unusual type of cancer-associated retinopathy in a patient with ovarian cancer

We studied a case of unusual retinopathy in a 35-year-old woman who presented with bilateral visual deterioration due to retinal pigmentary mottling and serous elevation in the posterior pole. Two years before, she had undergone hysterectomy and bilateral salphingo-oophorectomy for ovarian cancer. Her electroretinogram became subnormal, and her fluorescein angiogram exhibited multiple deep retinal pigment epithelial leakages and subretinal dye pooling in both eyes. Corticosteroid therapy failed to prevent visual loss. She was found to possess antibodies against retinal 45 kd protein. This led to a diagnosis of cancer-associated retinopathy with atypical protein profile. We report a rare variety of cancer-associated retinopathy in a patient with-ovarian cancer.

Iron-induced cytotoxicity in cultured rat retinal neurons

Oxidative stress has been proposed as a major injury mechanism in the central nervous system including the retina. In this study, as an initial attempt to study the mechanism of oxidative injury in the retina, we developed a cell culture model by utilizing the iron exposure paradigm. Exposure of rat retinal cultures for 24 hours to 10-40 MicroM ferrous or ferric chloride induced a concentration-dependent death of retinal neurons but not of photoreceptors or astrocytes. An antioxidant, trolox effectively attenuated the iron-induced death of neurons and photoreceptors in a dose-dependent manner whereas neither glutamate receptor antagonists nor cycloheximide were protective. Of retinal interneurons, GABAergic neurons were more vulnerable to the iron toxicity than calbindin (+) horizontal neurons. These findings show that iron exposure induces anti-oxidant-sensitive neuronal injury in retinal culture, independent of the excitotoxic or the apoptotic mechanisms. Of retinal neurons, different cell types exhibit differential vulnerabilities to the iron-induced oxidative injury. This simplified culture model system may be useful in elucidating mechanisms of oxidative injury in the retina.

Effect of Chagas' disease on nitric oxide-containing neurons in severely affected and unaffected intestine

PURPOSE

The pathophysiology of Chagas' disease is incompletely understood. Neuronal nitric oxide has been cited as a candidate neurotransmitter responsible for relaxation of the internal anal sphincter. Neuronal nicotinamide adenine dinucleotide phosphate diaphorase can be used as a marker for neuronal nitric oxide synthase. This study was designed to examine the alterations of the nitric oxide-containing neurons in the enteric nervous system of the colon of patients who underwent resections for advanced megacolon and to compare these specimens with small-bowel specimens from the same patients and with specimens from control subjects.

METHODS

Specimens from resected rectum and extramucosal small-bowel biopsy specimens from 11 patients with Chagas megacolon but no apparent small-bowel clinical involvement were compared with the uninvolved colon and jejunum of 10 control patients with colon cancer. Tissues were fixed in Zamboni solution and evaluated by histochemistry for nicotinamide adenine dinucleotide phosphate diaphorase-containing neurons. Reactivity was evaluated on a 0 to 4 scale in the longitudinal muscle, myenteric plexus, circular muscle, submucosal plexus, and mucosa.

RESULTS

Specimens from control patients showed well-stained myenteric and submucosal neurons and an abundant network of terminal nerve fibers in the muscle layers. Chagasic specimens had decreased staining in all layers of the gut. Overall there was a statistically significant decrease in nicotinamide adenine dinucleotide phosphate diaphorase-containing neurons. Biopsy specimens from clinically uninvolved small bowel of patients with Chagas' disease also showed decreased reactivity, but to a lesser degree.

CONCLUSIONS

Nicotinamide adenine dinucleotide phosphate diaphorase activity is decreased in patients with advanced megacolon. The alterations are more relevant in the myenteric plexus and the circular muscle. Reactivity is also diminished in the clinically uninvolved small bowel, but to a lesser extent.

Survival and function of hepatocytes on a novel three-dimensional synthetic biodegradable polymer scaffold with an intrinsic network of channels

OBJECTIVE

To evaluate the survival and function of hepatocytes (HCs) on a novel three-dimensional (3D) synthetic biodegradable polymer scaffold with an intrinsic network of interconnected channels under continuous flow conditions.

SUMMARY BACKGROUND DATA

The authors' laboratory has investigated HC transplantation using 3D biodegradable polymers as scaffolding as an alternative approach to treatment of end-stage liver disease. Previous studies have demonstrated survival of HCs transplanted on polymer discs in peripheral tissue sites and partial correction of single enzyme liver defects. One of the major limitations has been the insufficient survival of an adequate mass of transplanted cells; this is thought to be caused by inadequate oxygen diffusion.

METHODS

HCs and nonparenchymal liver cells from Lewis rats were seeded onto 3D biodegradable polymer scaffolds. Microporous 3D polymers were created using 3D printing on copolymers of polylactide-coglycolide. The cell/polymer constructs were placed in static culture or continuous flow conditions. The devices were retrieved after 2 days and examined by scanning electron microscopy and histology. Culture medium was analyzed for albumin by enzyme-linked immunosorbent assay (ELISA). Differences in culture parameters including pH, PCO2, PO2, glucose, lactate, and HCO3 were examined.

RESULTS

Scanning electron microscopy revealed successful attachment of HCs on the 3D polymer in both static and flow conditions. Histology demonstrated viable HCs in both conditions. ELISA demonstrated a significantly higher mean concentration of albumin in flow conditions than in static conditions. Culture parameter analysis revealed a significantly higher PO2 and glucose level, and a more physiologic pH in flow conditions than in static conditions.

CONCLUSIONS

HCs cocultured with nonparenchymal cells can attach to and survive on the 3D polymer scaffolds in both static and flow conditions in the size and configuration used in this study. Flow conditions may provide a more conducive environment for HC metabolism and albumin synthesis than static conditions. The authors hypothesize that flow through directed channels will be necessary for the transfer of large masses of cells when implantation studies are initiated.

Effect of petroleum ether extract of Panax ginseng roots on proliferation and cell cycle progression of human renal cell carcinoma cells

Panax ginseng roots have long been used as a medicinal herb in oriental countries. We have investigated anti-proliferative effects of lipid soluble Panax ginseng components on human renal cancer cell lines. Petroleum ether extract of Panax ginseng roots (GX-PE) or its partially purified preparation (7:3 GX) was added to cultures of three human renal cell carcinoma (RCC) cell lines, A498, Caki-1, and CURC II. Proliferation of RCC cells was estimated by a [3H]thymidine incorporation assay and cell cycle distribution was analyzed by flow cytometry. GX-PE, 7:3 GX, panaxydol and panaxynol inhibited proliferation of all three RCC cell lines in a dose dependent manner in vitro with an order of potency, 7:3 GX > panaxydol > panaxynol = GX-PE. Additive effect of interleukin 4 was also demonstrated, most prominently in Caki-1 which responded poorly to GX-PE alone. Analysis of cell cycle in CURC II and Caki-1 treated with GX-PE demonstrated increase in G1 phase population and corresponding decrease in S phase population. The present study demonstrated that proliferation of human RCC cell lines were inhibited by lipid soluble components of Panax ginseng roots by blocking cell cycle progression at G1 to S phase transition.

Percutaneous management of a bladder-drained pancreas transplant pseudocyst by a transcystic approach

BACKGROUND

We describe a 35-year-old male type 1 diabetic who underwent a cadaveric combined kidney-bladder-drained pancreas transplant with a duodenocystostomy for exocrine drainage who developed a large pelvic pseudocyst associated with a dilated pancreatic duct and an elevated serum amylase level.

METHODS

Due to the risk of surgical revision and the possibility of creating a cutaneous fistula with conventional percutaneous drainage, a pseudocyst-to-bladder drainage was performed. After the procedure, the catheter was capped to allow drainage of the pancreatic secretions into the bladder.

RESULTS

After drainage, the patient's serum amylase and lipase normalized along with resolution of the pseudocyst. The tube was removed after 19 weeks with no evidence of a recurrent pseudocyst and a normal serum amylase level.

CONCLUSION

The percutaneous pseudocyst-cystostomy obviated the need for surgical revision of the exocrine gland drainage and thus eliminated the morbidity and the potential risk of graft loss associated with such surgery.

[Diagnosis of blood flow in breast tumors with increased blood pressure. New possibility in tumor field diagnosis]

On the assumption that the architecture of blood vessels of malignant tumors, formed by neoangiogenesis, shows characteristics that are different from those of blood vessels of benign tumors or physiological findings, we have tried in the present study to investigate the behavior of these different vessels under increased blood pressure. Using a special stand, the same sonographic section could be stably maintained during an examination time of approx. 4 minutes. Using a new computer program, the color pixels of the employed Angio color technique were quantified and recorded as a function of the measured blood pressure. To increase blood pressure, the patient had to press a hand grip, which practically always caused a systolic blood pressure elevation of more than 15-20 mmHg. Seventy patients with sonographically detected breast tumors were examined; 54 (14 benign and 40 malignant tumors) could be included in the evaluation. We found four typical types of curves: Curve type 1 is associated with an instantaneous increase in blood flow with increased blood pressure, followed by a drop in the blood pressure, with a slow decrease in blood flow as the blood pressure drops (with 29 malignant and 3 benign tumors). Curve type 2 shows a continuous increase in blood flow-though somewhat delayed with respect to the rise in blood pressure-which is also observed when the blood pressure drops (exclusively benign tumors). In curve type 3, maximum blood flow is reached after the blood pressure maximum, and then the blood flow decreases (1 benign and 3 malignant tumors). Curve type 4 features decreased blood flow in spite of increased blood pressure (3 benign and 5 malignant tumors). The described quantification method, in combination with the stand, permits for the first time analysis of a tumor under increased blood pressure as to its blood flow behavior over time in an examination using a challenge test. Here one can find two distinctive curve types (types 1 and 2) that correlate mostly with malignant (type 1) or benign (type 2) breast tumors. Should this tendency be substantiated by additional large-scale studies, it would seem that a new ultrasonic possibility for differential diagnosis has been found.

Inhibitory effects of interleukin-4 on human renal cell carcinoma cells in vitro: in combination with interferon-alpha, tumor necrosis factor-alpha or interleukin-2

BACKGROUND

Immune cytokines have been shown to play important roles in regulating the growth of neoplastic cells, as well as the function of immune cells. The present study assessed the effects of interleukin (IL)-4 alone, and in combination with recombinant interferon (IFN)-alpha 2b, or with IL-2, or with tumor necrosis factor (TNF)-alpha on the in vitro proliferation of human renal cell carcinoma (RCC) cell-lines.

METHODS

Growth-inhibitory effects of IL-4 alone, and in combination with other cytokines, on three human RCC cell-lines, Caki-1, CURC-II, and A-498, were measured by the [3H]thymidine incorporation assay.

RESULTS

IL-4 inhibited proliferation of all three human RCC cell-lines (P < 0.001). The maximum growth inhibition of RCC cell-lines by IL-4 alone was observed at the concentration of 1 to 3 ng/mL, depending on the cell-line. Antihuman IL-4 antisera was able to reverse the growth-inhibitory effects of IL-4 on Caki-1 in a dose-dependent manner, proving that the growth inhibition was mediated by IL-4 itself. When other cytokines were added in combination with IL-4, only IFN-alpha 2b resulted in significant additional growth inhibition (P < 0.005). However, when the proliferation was compared to that of RCC cells that were not treated with any cytokine, all combinations produced marked growth inhibition.

CONCLUSION

Our data suggest that IL-4 alone, or in combination with IFN-alpha 2b, can be used to develop new strategies for treatment of human RCC.

Helicobacter pylori gastritis: radiographic findings

PURPOSE

To determine whether there are useful radiographic criteria for diagnosing Helicobacter pylori.

MATERIALS AND METHODS

Radiographs from double-contrast upper gastrointestinal examinations of 88 patients with H pylori and 41 control subjects were blindly reviewed. The results were analyzed by means of receiver operating characteristic (ROC) curves.

RESULTS

Thickened gastric folds were detected in 39 patients with H pylori (44%) and nine control subjects (22%). The area under the ROC curve was 0.62 (standard deviation [SD] = 0.05, P < .01). Among the 48 subjects with thickened gastric folds, polypoid gastritis with thickened, lobulated folds was detected in 24 patients with H pylori (62%) and four control subjects (44%). The area under the ROC curve was 0.59 (SD = 0.05, P < .01). No substantial differences were observed in the frequencies of gastric ulcers, erosive gastritis, gastric narrowing, duodenal ulcers, duodenitis, and duodenal narrowing in patients with and without H pylori.

CONCLUSION

The presence of thickened gastric folds was the best radiographic criterion for differentiating subjects with from those without H pylori.

Regulatory regions 3' of the immunoglobulin heavy chain intronic enhancer differentially affect expression of a heavy chain transgene in resting and activated B cells

We have compared the expression patterns of three Ig heavy chain transgenes. The three constructs differ only by deletion of J-C intron sequences located downstream of the Emu enhancer region. When stably transfected into a myeloma cell line, all three constructs are expressed at comparable levels. However, transgenic mice carrying each construct show dramatic differences in transgene expression. Our results indicate that, in addition to the Emu enhancer, at least two regions, RegA and RegS, within the J-C intron influence transgene expression. RegA, located directly downstream of the core Emu enhancer, is involved in up-regulation of transgene expression after LPS activation of splenocytes. RegS, located within or downstream of the Smu switch region, is important for normal levels of transgene expression in splenocytes of heavy chain transgenic mice.

Regulatory regions 3' of the immunoglobulin heavy chain intronic enhancer differentially affect expression of a heavy chain transgene in resting and activated B cells

We have compared the expression patterns of three Ig heavy chain transgenes. The three constructs differ only by deletion of J-C intron sequences located downstream of the Emu enhancer region. When stably transfected into a myeloma cell line, all three constructs are expressed at comparable levels. However, transgenic mice carrying each construct show dramatic differences in transgene expression. Our results indicate that, in addition to the Emu enhancer, at least two regions, RegA and RegS, within the J-C intron influence transgene expression. RegA, located directly downstream of the core Emu enhancer, is involved in up-regulation of transgene expression after LPS activation of splenocytes. RegS, located within or downstream of the Smu switch region, is important for normal levels of transgene expression in splenocytes of heavy chain transgenic mice.

Artificial reflex arc: a potential solution for chronic aspiration. III: Stimulation of implanted cervical skin as a functional graft triggering glottic closure in the canine

Stroke often impairs the ability of the vocal cords to close during deglutition, resulting in aspiration. The current study is a further advance on the application of the concept of an artificial reflex arc during swallowing. The second and third cervical branches were bilaterally isolated in four dogs and baseline sensory nerve traffic was detected via tripolar perineural electrodes. Cervical skin pressure-induced suprathreshold signals were used to trigger vocal cord contraction via bipolar electrodes passed around the recurrent laryngeal nerves. Skin subtended by the cervical nerves was implanted over the lateral aspect of the pyriform sinuses for 1 week. After reexploration, glottic closure was verified on videotape as surges in sensory nerve traffic were induced by mechanical stimulation of the pharynx. The possibility of artifactual stimulation was ruled out by lack of electrode motion during pharyngeal stimulation, spontaneous firing in the sensory nerve during light anesthesia, and sensory frequency differing from ambient 60-Hz noise. This article introduces the concept of autogenous functional graft as a basis for afferent information in electronic systems for dynamic rehabilitation of swallowing disorders.

Photoastigmatic refractive keratectomy in 168 eyes: six-month results

Using a 193 nm excimer laser, we performed elliptical astigmatic and spherical corneal ablation on 168 eyes with compound myopic astigmatism and analyzed the three- and six-month postoperative results. Mean preoperative astigmatism was 1.51 +/- 0.81 diopters (D). Mean three- and six-month postoperative astigmatism was 0.70 +/- 0.58 D and 0.67 +/- 0.60 D, respectively. Six months after surgery, eyes with less than 1.00 D preoperative astigmatism improved 4.8%. The improvement was 53.5% and 59.1% for eyes with a preoperative astigmatism of 1.00 D to 2.00 D and above 3.00 D, respectively. Overall, astigmatism improved 55.6%. There was a wide distribution from overcorrection to undercorrection. Astigmatism six months after surgery was within 10 degrees of the preoperative axis in 46.1% of eyes.

Somatic hypermutation of an immunoglobulin mu heavy chain transgene

We have analyzed somatic hypermutation of an immunoglobulin (Ig) heavy chain transgene. Hybridomas expressing the transgene were produced from immunized transgenic mice and transgene copies were sequenced to assay for mutation. In two IgM-producing hybridomas, as well as in several IgG-producing hybridomas, mutations were found in the VDJ region of the transgene. In the IgM-producing hybridomas, both mutated and unmutated transgene copies were present and expressed as mRNA. Several mutated transgene copies were present in a single cell and these showed different patterns of mutation. Two IgG-producing hybridomas isolated from a single animal also showed a hierarchical pattern of mutation indicating that transgene mutations can accumulate during B cell proliferation, similar to the mutational process for endogenous antibody genes. Among hybridomas that expressed both IgG and IgM molecules derived from the transgene, the isotype-switched gamma transgene copy exhibited a higher level of mutation than the mu transgene copies. Our results indicate that the 15-kb ARSmu transgene contains all the sequence information required to target the Ig-specific hypermutational machinery, and raise the possibility that sequences associated with the endogenous CH locus might enhance somatic mutation.

Zinc does not acutely suppress prolactin in normal or hyperprolactinemic women

In rat pituitary cells in vitro physiological zinc concentrations selectively inhibit basal and stimulated PRL release. This study was done to investigate the serum PRL response to an oral zinc challenge in vivo. Eight hyperprolactinemic [mean serum PRL, 76.0 +/- 43.8 (+/- SD) micrograms/L] and 10 normal (mean serum PRL, 9.6 +/- 2.8 micrograms/L) women were studied. All women had normal thyroid, renal, and hepatic function, and none was taking any medications. Each was studied twice, after both oral zinc (50 mg) and placebo, given in random order. Blood was withdrawn every 15 min from 30 min before to 210 min after zinc or placebo administration; TRH (500 micrograms) was given iv at 180 min. Both hyperprolactinemic and normal women absorbed the zinc well, achieving similar maximal plasma zinc levels [hyperprolactinemic women, 39.5 +/- 6.9 (+/- SD) mumol/L; normal women, 33.3 +/- 7.0; P less than 0.001 vs. placebo]. When 2 women who became symptomatic after zinc administration were excluded, there were no significant differences in basal or TRH-stimulated serum PRL levels after zinc vs. placebo. These findings indicate that zinc is not involved in the acute in vivo regulation of PRL secretion in humans.

Multiple forms of human pancreatic growth hormone releasing factor-like immunoreactivity in teleost brain and pituitary

Two anatomically distinct neuronal GRF systems in the brain-pituitary of the teleost codfish (Gadus morhua), immunohistochemically localized by use of antisera directed against hpGRF1-44NH2 and hpGRF1-40OH are described. Chromatographic analysis additionally revealed the presence of three molecular variants of immunoreactive hpGRF1-44NH2, two of which differ from the authentic human material. However, all three forms released GH from rat pituitary cells in dispersed culture. These findings indicate that hpGRF is highly conserved in nature and suggest that peptides closely related to this human hypothalamic releasing hormone regulate the teleost pituitary.