Changes in glutathione homeostasis during liver regeneration in the rat

We have shown previously that plating primary cultures of rat hepatocytes under low density, which stimulates hepatocytes to shift from the G0 to the G1 phase of the cell cycle, resulted in increased levels of glutathione (GSH) and cysteine, and increased activity of gamma-glutamylcysteine synthetase (GCS), the rate-limiting enzyme in GSH synthesis (Lu et al., Am. J. Physiol. 1992;263:C1181-C1189). In the current work we examined changes in GSH homeostasis after two-thirds partial hepatectomy (PH). Male Sprague-Dawley rats underwent two-thirds PH or sham operation. GSH, oxidized glutathione (GSSG), cysteine, GSH efflux, DNA synthesis, changes in GCS subunit messenger RNA (mRNA), and protein levels were measured 12 and 24 hours after PH. Both liver GSH and cysteine levels were doubled at 12 hours and remained elevated at 24 hours after PH. GSSG levels also increased, but the ratio of GSH to GSSG levels remained unchanged. The increase in GSH and cysteine levels preceded the increase in DNA synthesis. Sinusoidal GSH efflux was unchanged after two-thirds PH, but biliary GSH efflux decreased. However, total GSH efflux was minimally altered after two-thirds PH. The increase in GSH can be largely accounted for by the increase in both cysteine availability and the activity of GCS. The steady-state mRNA and protein levels of the GCS heavy subunit were increased at 12 hours after PH. The mRNA level of the GCS light subunit was unchanged. In summary, early in the course of liver regeneration the steady-state hepatic GSH levels double because of an increase in the biosynthesis of GSH.

The effect of age on the association between body-mass index and mortality

BACKGROUND

The effect of age on optimal body weight is controversial, and few studies have had adequate numbers of subjects to analyze mortality as a function of body-mass index across age groups.

METHODS

We studied mortality over 12 years among white men and women who participated in the American Cancer Society's Cancer Prevention Study I (from 1960 through 1972). The 62,116 men and 262,019 women included in this analysis had never smoked cigarettes, had no history of heart disease, stroke, or cancer (other than skin cancer) at base line in 1959-1960, and had no history of recent unintentional weight loss. The date and cause of death for subjects who died were determined from death certificates. The associations between body-mass index (defined as the weight in kilograms divided by the square of the height in meters) and mortality were examined for six age groups in analyses in which we adjusted for age, educational level, physical activity, and alcohol consumption.

RESULTS

Greater body-mass index was associated with higher mortality from all causes and from cardiovascular disease in men and women up to 75 years of age. However, the relative risk associated with greater body-mass index declined with age. For example, for mortality from cardiovascular disease, the relative risk associated with an increment of 1 in the body-mass index was 1.10 (95 percent confidence interval, 1.04 to 1.16) for 30-to-44-year-old men and 1.03 (95 percent confidence interval, 1.02 to 1.05) for 65-to-74-year-old men. For women, the corresponding relative risk estimates were 1.08 (95 percent confidence interval, 1.05 to 1.11) and 1.02 (95 percent confidence interval, 1.02 to 1.03).

CONCLUSIONS

Excess body weight increases the risk of death from any cause and from cardiovascular disease in adults between 30 and 74 years of age. The relative risk associated with greater body weight is higher among younger subjects.

Aerosol cyclosporine prevents acute allograft rejection in experimental lung transplantation

BACKGROUND

The incidence of acute rejection and the morbidity of systemic cyclosporine (INN: cyclosporine) after lung transplantation is significant. Experimental evidence suggests that the allograft locally modulates the immune mechanisms of acute rejection. The purpose of this study was to determine whether aerosolized cyclosporine would prevent acute cellular rejection, achieve effective graft concentrations with low systemic drug delivery, and locally affect production of the inflammatory cytokines involved in acute rejection.

METHODS

Unilateral orthotopic left lung transplantation was performed in 64 rats (ACI to Lewis), which were divided into eight groups (each group, n = 8): group A, no treatment; groups B to D, aerosol cyclosporine 1 to 3 mg/kg per day, respectively; group E to H, systemic cyclosporine 2, 5, 10, and 15 mg/kg per day, respectively. After the animals were killed on postoperative day 2, 4, or 6, the transplanted lung, native lung, spleen, and blood were collected. Histologic studies, high-pressure liquid chromatography for trough cyclosporine concentrations, and reverse-transcriptase polymerase chain reaction for cytokine gene expression were performed.

RESULTS

Untreated animals showed grade 4 rejection by postoperative day 6. Aerosol cyclosporine prevented acute rejection in a dose-dependent fashion, with group D animals (3 mg/kg per day) showing minimal grade 1 changes. Among animals receiving systemic cyclosporine, only group H (15 mg/kg per day) controlled (grade 1) rejection. However, aerosol cyclosporine, at an 80% lower dose, achieved significantly lower concentrations of cyclosporine in the graft (12,349 vs 28,714 ng/mg, p = 0.002004) and blood (725 vs 3306 ng/ml, p = 0.000378). Group F (systemic 5 mg/kg per day) had higher cyclosporine concentrations in the blood than group D (p = 0.004572) and similar tissue concentrations (p = 0.115180), yet had grade 2 rejection. Reverse-transcriptase polymerase chain reaction demonstrated equivalent suppression of inducible nitric oxide synthase but a 20- to 25-fold higher expression of interleukin-6, interleukin-10, and interferon-gamma in group D versus group H recipient allografts.

CONCLUSION

Local delivery of cyclosporine by aerosol inhalation dose-dependently prevented acute pulmonary allograft rejection. Effective graft levels and low systemic drug delivery required significantly lower doses than systemic therapy alone. The gene expression of proinflammatory cytokines involved in allograft rejection was suppressed by aerosol cyclosporine therapy.

Gap junctional communication and the tyrosine phosphorylation of connexin 43 in interaction between breast cancer and endothelial cells

Abnormal gap junction communication (GJC) has been associated with carcinogenesis. We investigated the role of endothelial cell GJC and connexin 43 (Cx43), the main gap junction protein in these cells, during tumour cell extravasation. GJC was determined by the ability of cells to transfer Lucifer yellow, to neighbouring cells. Tumour-endothelial interaction was assessed by DiI assay. Connexin 43 expression and tyrosine phosphorylation were measured by immunoprecipitation and Western blotting. Co-culturing of ECV304 endothelial cells with human breast cancer cells resulted in a rapid and transient loss of communication competence of ECV304. This inhibition was maximal within 5 min. GJC was almost fully restored in 2 h. The co-culturing also resulted in an increase in the tyrosine phosphorylation of CX43. The pattern of phosphorylation was similar to the loss and the recovery of GJC in ECV304. We conclude that interaction of tumour cells with endothelium effectively inhibits GJC of endothelial cells, which is attributed to the increased tyrosine phosphorylation of connexin 43. This may contribute to the extravasation of tumour cells from the circulation, an essential step in the establishment of metastasis.

Effects of Tripterygium wilfordii hook F extracts on induction of cyclooxygenase 2 activity and prostaglandin E2 production

OBJECTIVE

Extracts of the Chinese herbal remedy Tripterygium wilfordii Hook F (TWHF) have been reported to be effective in the treatment of patients with a variety of inflammatory and autoimmune diseases, but the mechanism of this therapeutic effect has not been completely delineated. The present study was designed to assess the effects of TWHF on the in vitro synthesis of prostaglandin E2 (PGE2) and on the expression of the cyclooxygenase isoforms, COX-1 and COX-2, in various human cell types.

METHODS

Monocytes from human peripheral blood (HM), fibroblasts from rheumatoid arthritis synovial tissue (RASF), human neonatal foreskin fibroblasts (HFF), and the histiocytic cell line U937 were cultured for designated time periods with or without lipopolysaccharide (LPS), and in the presence or absence of varying concentrations of the following inhibitors: the methanol/chloroform (T2) extract of TWHF, the ethyl acetate (EA) extract of TWHF, a purified diterpenoid component of TWHF (triptolide), dexamethasone, and indomethacin. Culture supernatants were harvested for PGE2 content assays. Total RNA was extracted from the cells and analyzed for COX-1 and COX-2 messenger RNA (mRNA) expression using reverse transcriptase-polymerase chain reaction or Northern blotting.

RESULTS

Both the T2 and EA extracts inhibited PGE2 synthesis in the LPS-stimulated HM, RASF, and HFF cells, which was reflected by a marked suppression in the levels of mRNA for COX-2. In contrast, neither extract inhibited PGE2 production in U937 cells that did not express COX-2. Triptolide also inhibited LPS-stimulated induction of COX-2 mRNA and synthesis of PGE2, at the same inhibitory concentration as seen with the EA extract. The effects of T2, EA, and triptolide paralleled the inhibitory action of dexamethasone.

CONCLUSION

The data indicate that both the T2 and EA extracts of TWHF, as well as the triptolide component, inhibit PGE2 production in a variety of human cells by blocking the up-regulation of COX-2.

[Surgical treatment of extrahepatic bile duct carcinoma]

OBJECTIVE

To evaluate the experience in the diagnosis and surgical treatment of the extrahepatic bile duct carcinomas.

METHODS

242 patients with extrahepatic bile duct carcinoma over the past 20 years was retrospectively studied.

RESULTS

The origin points were carcinomas of the upper bile duct in 168, of the middle bile duct in 18, and of the lower bile duct in 56 patients. The preoperative diagnostic rates for the location and the nature of the lesion were respectively raised to 97.2% and 94.5% by combination of ultrasonography and CT. The curative resection rates for the tumors in the upper, middle, and lower bile duct over the recent five years reached to 50.0%, 50.0% and 71.4%. respectively. Follow-up of patients with curative resection showed a one year recurrent rate of 73.9% and a three year recurrent rate of 100.0% with a mean recurrent time of 9.6 months in patients with local metastasis, in contrast to 13.3%, 71.4% and 17.5 months in those without metastasis. Metastasis was mainly responsible for the recurrence. Liver or multiple organ failure, intra-abdominal infection and gastrointestinal hemorrhage were the common and serious complications.

CONCLUSION

The case number of the bile duct carcinoma presented a remarkable increment tendency. Ultrasonography and CT were satisfactory enough for diagnosis. To reduce the recurrent rate, resection of the tumor together with the lymph, nervous, fatty and connective tissues in the hepatic hilus, even the right celiac ganglia, should be considered the necessary procedure. Monitoring and protecting the main organs to prevent the multiple organ failure, controlling the gastrointestinal hemorrhage and the intra-abdominal infection are important to decreasing the mortality.

[Study on microsatellite instability in gastric cancer]

OBJECTIVE

To evaluate the microsatellite instability (MIN) in gastric cancers (GC).

METHODS

MIN was examined in 106 cases of GC, using the radioactive polymerase chain reaction-based method.

RESULTS

The frequency of MIN was significantly higher in expanding type of GC as compared with the infiltrative type (P < 0.005, chi 2 test). No significant association with histologic type, pTNM stage, age and sex was found (P > 0.05, chi 2 test).

CONCLUSIONS

These findings reveal that MIN might be an important contributor to the development and progress of a significant number of GC, especially the expanding type which, as acknowledged traditionally, has a favorable prognosis.

Boron-containing polyamines as DNA targeting agents for neutron capture therapy of brain tumors: synthesis and biological evaluation

Three series of new boron-containing spermidine/spermine (SPD/SPM) analogues have been synthesized: N1- and N5-(4-carboranylbutyl) SPD/SPM derivatives (SPD-1, SPD-5, SPM-1, SPM-5); N1,N10-diethyl-N5-(4-carboranylbutyl)spermidine (DESPD-5), N1,N14-diethyl-N5-(4-carboranylbutyl)spermine (DESPM-5); and N5,N10-bis(4-carboranylbutyl)spermine (SPM-5,10). In vitro studies using rat F98 glioma cells have shown that these polyamines retain the ability to displace ethidium bromide from calf thymus DNA and are rapidly taken up by F98 glioma cells. However, their cytotoxicities, especially those with terminal N-substituted (SPD-1, SPM-1) boron compounds, are greater than those of SPD/SPM. Nevertheless, the groundwork has been created for a new class of boron-containing compounds that maybe useful for boron neutron capture therapy of tumors.

Elevations in cathepsin B protein content and enzyme activity occur independently of glycosylation during colorectal tumor progression

Western blots, enzyme assays, protein glycosylation studies, and immunohistochemical staining were used to characterize cathepsin B expression at successive stages of colorectal tumor progression. In normal colon mucosa and premalignant adenomas, cathepsin B expression was predominantly due to mature two-chain protein detected on Western blots as the nonglycosylated 27-kDa form, with overexpression of this protein occurring in only 4 of 18 adenomas. Overexpression increased significantly in Dukes A and B carcinomas (26 of 37 cases), with cathepsin B protein generally detectable in carcinomas as a combination of both 27-kDa nonglycosylated and 28-kDa glycosylated mature two-chain forms. Glycosylated cathepsin B protein in carcinoma extracts was sensitive to PNGase F but resistant to Endo H, indicating a pattern consistent with complex rather than high mannose type glycosylation. When sorted by advancing tumor stage, peak expression of cathepsin B protein occurred in carcinomas involved in local invasion compared with adenomas or metastatic cancers. At all stages, cathepsin B activity correlated significantly with the levels of heavy chain mature cathepsin B protein (r = 0.6682, p < 0.0001) irrespective of glycosylation. Immunohistochemical staining of cathepsin B protein revealed fine diffuse cytoplasmic staining in both adenomas and carcinomas compared with coarse granular cytoplasmic staining (typical of lysosomes) seen in matched normal mucosa. Our results demonstrate several sequential, apparently independent changes in cathepsin B expression during colorectal tumor progression including early changes in subcellular localization, up-regulation of cathepsin B protein and activity in invasive cancers, and altered protein glycosylation detected in malignant tumors at all stages.

[Recovery of motor function of spinal cord with embryonic spinal cord graft in adult rat]

The capacity of embryonic spinal cord tissue in the repair of injured structure of spinal cord has been noted for years. In order to investigate the embryonic spinal cord graft in the repair of motor function of injured spinal cord, the embryonic spinal cord tissue was transplanted to the hemisection cavity in spinal cord in adult rat. One hundred adult Wistar Rats were used to simulate the hemisectional injury of spinal cord by drilling 2-3 mm cavity in lumbar enlargement. Sixty rats were treated with rat embryonic spinal cord tissue grafting while the other forty were chosen as control. The outcome was evaluated according the combined behavioural score (CBS) and motor evoked potential (MEP) in the 1, 2, 4 and 12 weeks. The grafting group was superior to the control as assessed by CBS (P < 0.05), especially within 4 weeks. (P < 0.01). The restoration of the latent peak of early wave(P1, N1) was better in the grafting group, too. This suggested that embryonic spinal cord graft could improve the recovery of motor function of injured spinal cord in adult rat. The effect of the embryonic spinal cord tissue graft might be concerned with its secretion of several kinds of neurotrophic factors, nerve growth factor, nerve transmitted factor, or adjustment of hormone.

Use of a luminescent bacterial biosensor for biomonitoring and characterization of arsenic toxicity of chromated copper arsenate (CCA)

An arsenic oxyanion-inducible Escherichia coli chromosomal operon (arsRBC) has been previously identified. Construction of a luciferase transcriptional gene fusion (arsB::luxAB) showed that ars operon expression, plus concomitant cell luminescence, was inducible in a concentration-dependent manner by arsenic salts. The present study was conducted to evaluate the potential of the arsB::luxAB transcriptional gene fusion for use as a biosensor in monitoring the toxicity of arsenic compounds. Cultures from this gene fusion strain were exposed to increasing concentrations of the wood preservative chromated copper arsenate (CCA), as well as its constituents, sodium arsenate and chromated copper solution (CC). Analysis of luciferase activity revealed that the arsB::luxAB gene fusion was expressed in response to CCA and sodium arsenate, but not to the CC solution. The detection limit of arsenic was found to be 0.01 microgram As/ml (10 parts per billion, 10 ppb) and therefore well within the range of environmental concerns. A greater induction of luminescence by arsenate was observed when cells were limited for phosphate, as phosphate can act as a competitive inhibitor of arsenate ions. Our results suggest that the E. coli arsB::luxAB fusion strain has a promising future as a specific and sensitive biosensor for monitoring bioavailable levels and toxicity of arsenic near sites where CCA-treated wood has been used.

[Therapy for 29 sarcoma of the breast]

We discuss the best therapeutic method for sarcoma of the breast. The data of all cases treated from March 1964 to May 1994 were analyzed retrospectively. Of all cases, 7 died, 9 recurred, and 15 survived more than 15 years and 5 over 20 years. The follow-up time was 4 months to 25 years. Most sarcomas were pathologically proved. The best therapeutic method was operation. The sarcomas of all cases must be extensively resected including surrounding tissues. The recurrent sarcoma should be resected again. The axillary lymphnodes should not be eliminated when lymphnodes is not discovered.

Transcriptional regulation of the gltA and TLC genes in Rickettsia prowazekii growing in a respiration-deficient host cell

The regulation of the citrate synthase (gltA) and ATP/ADP translocase (tlc) genes of the obligate intracellular bacterium, Rickettsia prowazekii, was analyzed in rickettsia-infected respiration-deficient G14 cells. The level of the gltA mRNAII and the tlc mRNA was much lower in the total RNA isolated from the infected G14 cells grown in 1 g/l glucose (low glucose, GL) medium than in that from infected G14 cells grown in 4.5 g/l glucose (high glucose, GH) medium. However, the level of the gltA mRNAI relative to 16 S rRNA was the same in GL and GH media. An increase in the level of the gltA mRNAII and the tlc mRNA could be observed as early as 2 hrs after shifting from GL to GH medium. We conclude that, under these experimental conditions, the tlc promoter and the gltA promoter P2, but not gltA promoter P1, were transcriptionally regulated.

Estimating the mean hazard ratio parameters for clustered survival data with random clusters

We consider a latent variable hazard model for clustered survival data where clusters are a random sample from an underlying population. We allow interactions between the random cluster effect and covariates. We use a maximum pseudo-likelihood estimator to estimate the mean hazard ratio parameters. We propose a bootstrap sampling scheme to obtain an estimate of the variance of the proposed estimator. Application of this method in large multi-centre clinical trials allows one to assess the mean treatment effect, where we consider participating centres as a random sample from an underlying population. We evaluate properties of the proposed estimators via extensive simulation studies. A real data example from the Studies of Left Ventricular Dysfunction (SOLVD) Prevention Trial illustrates the method.

Vascular MADs: two novel MAD-related genes selectively inducible by flow in human vascular endothelium

Vascular endothelium is an important transducer and integrator of both humoral and biomechanical stimuli within the cardiovascular system. Utilizing a differential display approach, we have identified two genes, Smad6 and Smad7, encoding members of the MAD-related family of molecules, selectively induced in cultured human vascular endothelial cells by steady laminar shear stress, a physiologic fluid mechanical stimulus. MAD-related proteins are a recently identified family of intracellular proteins that are thought to be essential components in the signaling pathways of the serine/threonine kinase receptors of the transforming growth factor beta superfamily. Smad6 and Smad7 possess unique structural features (compared with previously described MADs), and they can physically interact with each other, and, in the case of Smad6, with other known human MAD species, in endothelial cells. Transient expression of Smad6 or Smad7 in vascular endothelial cells inhibits the activation of a transfected reporter gene in response to both TGF-beta and fluid mechanical stimulation. Both Smad6 and Smad7 exhibit a selective pattern of expression in human vascular endothelium in vivo as detected by immunohistochemistry and in situ hybridization. Thus, Smad6 and Smad7 constitute a novel class of MAD-related proteins, termed vascular MADs, that are induced by fluid mechanical forces and can modulate gene expression in response to both humoral and biomechanical stimulation in vascular endothelium.

Differential regulation of gamma-glutamylcysteine synthetase heavy and light subunit gene expression

gamma-Glutamylcysteine synthetase (GCS) is the rate-limiting enzyme in the biosynthesis of glutathione and is composed of a heavy and a light subunit. Although the heavy subunit is enzymically active alone, the light subunit plays an important regulatory role by making the holoenzyme function more efficiently. In the current study we examined whether conditions which are known to influence gene expression of the heavy subunit also influence that of the light subunit, and the mechanisms involved. Treatment of cultured rat hepatocytes with hormones such as insulin and hydrocortisone, or plating hepatocytes under low cell density increased the steady-state mRNA level of the heavy subunit only. Treatment with diethyl maleate (DEM), buthionine sulphoximine (BSO) and t-butylhydroquinone (TBH) increased the steady state mRNA level and gene transcription rates of both subunits. These treatments share in common their ability to induce oxidative stress and activate nuclear factor kappa B (NF-kappa B). Treatment with protease inhibitors 7-amino-1-chloro-3-tosylamido-2-heptanone (TLCK) or L-1-tosylamido-2-phenylethyl chloromethyl ketone (TPCK) had no influence on the basal NF-kappa B and GCS subunit mRNA levels, but blocked the activation of NF-kappa B by DEM, BSO and TBH, and the increase in GCS heavy subunit mRNA level by BSO and TBH. On the other hand, the DEM-, BSO- and TBH-induced increase in GCS light-subunit mRNA level was unaffected by TLCK and TPCK. Thus only the heavy subunit is hormonally regulated and growth sensitive, whereas both subunits are regulated by oxidative stress. Signalling through NF-kappa B is involved only in the oxidative-stress-mediated changes in the heavy subunit gene expression.

A method for more efficient source localization of interstitial implants with biplane radiographs

The conventional method for source localization in an interstitial ribbon implant by means of biplane radiographs can be difficult, especially when a large number of seeds are involved. We present a new algorithm for more efficient source localization with the same conventional biplane radiographs. The method does not require a one-to-one source correspondence between two radiographs. The user needs only to digitize several points, following the shape of each ribbon from both films. The points that are digitized do not need to be the location of the seeds, and they do not have to correspond to the same points on both films. The algorithm uses the multidimensional minimization method to reconstruct the three-dimensional locus of the ribbon. The location of each seed is then determined by its pathlength relative to the corresponding starting point. We have used phantom experiments and clinical cases to test the reliability of the algorithm. The results show that the errors in the determination of seed locations are less than 2 mm, and the efficiency in source digitization for data entry can be increased by a factor up to 5.

[Changes of cardiac function during +Gz exposure in rabbits]

Changes of cardiac function was studied during +Gz exposure in rabbits. Seven New Zealand rabbits were anesthetized and exposed to +2, +4, and +6 Gz (each for 30s, onset rate 1G/s, with 15 min interval in between). The left ventricular systolic pressure (LVSP), peak rate of left ventricular pressure rising (+dp/dtmax) and ECG were recorded. The results showed that during +2, +4 and +6 Gz exposures, LVSP decreased by 62.96% (P<0.01), 63.34% (P<0.01) and 82.01% (P<0.01) respectively, and +dp/dtmax decreased by 58.46% (P<0.01), 53.59% (P<0.01) and 63.06% (P<0.01) respectively, and the left ventricular end diastolic pressure decreased by 67.78 % (P>0.05), 332.74 % (P<0.01) and 500.54% (P<0.01) respectively, as compared with those of control. It is suggested that cardiac function is depressed with +Gz exposure.

Seven outbreaks of trichinosis in China (1992-1996)

Seven outbreaks of trichinosis occurred in Zhengzhou (central China) from 1992 to 1996, 250 patients were diagnosed. Trichinella larvae were found in 3 of 4 portions of the pork examined and in 5 of 7 cases by muscle biopsy. There was a higher occurrence of outbreaks in winter. Young and middle-aged workers, cadres and merchants were the majority of patients, (higher in males than in females). The most important clinical manifestations were fever, eyelid edema, tiredness and eosinophilia without any gastrointestinal symptoms, rash and with less myalgia. Anti-Trichinella antibodies were detected by IF in 62.6% individuals with the history of infection. The specific antibodies were only observed in 78% patients one week after onset of disease, while the antibody positive rate was increased to 92.5%, 97.6% and 100% two, three, four and five weeks after the onset and evidently increased from 89.6% before therapy to 100% one week after therapy, and decreased to 74.6% and 23.7% one and four months after therapy respectively, which suggested that IF was a useful tool for immunodiagnosis and checking up therapeutic effect of trichinosis.

Interleukin 6 and interferon-gamma gene expression in lung transplant recipients with refractory acute cellular rejection: implications for monitoring and inhibition by treatment with aerosolized cyclosporine

BACKGROUND

The purpose of this study was to correlate cytokine gene expression from bronchoalveolar lavage (BAL) cells and peripheral blood lymphocytes (PBL) with graft histology in recipients with persistent acute rejection treated with aerosolized cyclosporine (ACsA).

METHODS

We measured mRNA for interleukin (IL) 6, interferon (IFN)-gamma, and IL-10 in recipients (1) without rejection (n=13), (2) with acute rejection that responded to pulsed methylprednisolone (n=7), and (3) with "refractory" acute rejection that failed to respond to conventional immunosuppression (n=17). In the latter group, ACsA was initiated.

RESULTS

BAL cell IL-6 and IFN-gamma were highest in recipients with refractory rejection compared with recipients with steroid-responsive rejection and recipients with no rejection. Improvement in rejection histology occurred in 15 of 17 recipients who were treated with ACsA. IL-6 and IFN-gamma mRNA levels from BAL cells decreased during treatment with ACsA (median IL-6:actin ratio: before treatment, 0.40 vs. after treatment, 0.003, P=0.001; IFN-gamma:actin ratio: before treatment, 0.32 vs. after treatment, 0.04, P=0.001). PBL IL-6 and IFN-gamma mRNA expression also decreased during ACsA treatment after 180 days. Expression of IL-10 mRNA from BAL and PBL did not change during ACsA treatment (0.0 vs. 0.03 and 0.0 vs. 0.02, respectively).

CONCLUSIONS

IL-6 and IFN-gamma mRNA expression from BAL cells was highest in those recipients with refractory histologic acute rejection. ACsA was associated with decreased IFN-gamma and IL-6 gene expression in BAL cells and PBL.

A complex consisting of human replication factor C p40, p37, and p36 subunits is a DNA-dependent ATPase and an intermediate in the assembly of the holoenzyme

Human replication factor C (hRFC) is a multi-subunit protein complex capable of supporting proliferating cell nuclear antigen (PCNA)-dependent DNA synthesis by DNA polymerases delta and epsilon. The hRFC complex consists of five different subunits with apparent molecular masses of 140, 40, 38, 37, and 36 kDa. We have previously reported the expression of a three-subunit core complex, consisting of the p40, p37, and p36 subunits following coupled in vitro transcription-translation of the cDNAs encoding these proteins (Uhlmann, F., Cai, J., Flores-Rozas, H., Dean, F. B., Finkelstein, J. , O'Donnell, M., and Hurwitz, J. (1996) Proc. Natl. Acad. Sci. U. S. A. 93, 6521-6526). Here we describe the isolation of a stable complex composed of the p40, p37, and p36 subunits of hRFC from baculovirus-infected insect cells. The purified p40.p37.p36 complex, like the five-subunit RFC, contained DNA-dependent ATPase activity that was stimulated by PCNA, preferentially bound to primed DNA templates, interacted with PCNA, and was capable of unloading PCNA from singly-nicked circular DNA. In contrast to the five-subunit RFC, the three-subunit core complex did not load PCNA onto DNA. The p40. p37.p36 complex inhibited the elongation of primed DNA templates catalyzed by the DNA polymerase delta holoenzyme. Incubation of the p40.p37.p36 complex with the hRFC p140 and p38 subunits formed the five-subunit hRFC complex that supported PCNA-dependent DNA synthesis by DNA polymerase delta.

Exposure of infants to phyto-oestrogens from soy-based infant formula

BACKGROUND

The isoflavones genistein, daidzein, and their glycosides, found in high concentrations in soybeans and soy-protein foods, may have beneficial effects in the prevention or treatment of many hormone-dependent diseases. Because these bioactive phyto-oestrogens possess a wide range of hormonal and non-hormonal activities, it has been suggested that adverse effects may occur in infants fed soy-based formulas.

METHODS

To evaluate the extent of infant exposure to phyto-oestrogens from soy formula, the isoflavone composition of 25 randomly selected samples from five major brands of commercially available soy-based infant formulas were analysed, and the plasma concentrations of genistein and daidzein, and the intestinally derived metabolite, equol, were compared in 4-month-old infants fed exclusively soy-based infant formula (n = 7), cow-milk formula (n = 7), or human breast-milk (n = 7).

FINDINGS

All of the soy formulas contained mainly glycosides of genistein and daidzein, and the total isoflavone content was similar among the five formulas analysed and was related to the proportion of soy isolate used in their manufacture. From the concentrations of isoflavones in these formulas (means 32-47 micrograms/mL), the typical daily volume of milk consumed, and average bodyweight, a 4-month-old infant fed soy formula would be exposed to 28-47 per day, or about 4.5-8.0 mg/kg bodyweight per day, of total isoflavones. Mean (SD) plasma concentrations of genistein and daidzein in the seven infants fed soy-based formulas were 684 (443) ng/mL and 295 (60) ng/mL, respectively, which was significantly greater (p < 0.05) than in the infants fed either cow-milk formulas (3.2 [0.7] and 2.1 [0.3] ng/mL), or human breast-milk (2.8 [0.7] and 1.4 [0.1] ng/mL), and an order of magnitude higher per bodyweight than typical plasma concentrations of adults consuming soy foods.

INTERPRETATION

The daily exposure of infants to isoflavones in soy infant-formulas is 6-11 fold higher on a bodyweight basis than the dose that has hormonal effects in adults consuming soy foods. Circulating concentrations of isoflavones in the seven infants fed soy-based formula were 13000-22000 times higher than plasma oestradiol concentrations in early life, and may be sufficient to exert biological effects, whereas the contribution of isoflavones from breast-milk and cow-milk is negligible.