Primary Sjögren's syndrome and deficiency of ICA69

BACKGROUND

Sjögren's syndrome is a common (about 1% of the population) autoimmune disease of salivary and lacrimal glands. Its cause and pathogenesis are poorly understood, and treatments are mostly for symptoms of the disease. ICA69 is a self-antigen expressed in brain, pancreas, salivary, and lacrimal glands. NOD-strain mice are an animal model of spontaneous Sjögren's syndrome. We aimed to assess the role of ICA69 in autoimmunity against Sjögren's syndrome.

METHODS

We inactivated the genomic ICA69 locus, generated NOD congenic mice that were deficient in ICA69, and assessed development of Sjögren's syndrome. ICA69 autoimmunity was investigated in controls and in patients with primary Sjögren's syndrome or systemic lupus erythematosus, and in various NOD mice, some of which were given an ICA69-directed prototype peptide vaccine.

FINDINGS

Disruption of the ICA69 locus prevented lacrimal gland disease and greatly reduced salivary gland disease in NOD mice. In healthy NOD mice, ICA69-specific T cells accumulated in lymph nodes that drain salivary tissue. T-cell and B-cell autoreactivity against ICA69 was much the same in patients with primary Sjögren's syndrome, but not in those with systemic lupus erythematosus or in healthy controls. Immunotherapy with a high-affinity mimicry peptide targeting ICA69-specific T-cells reduced established Sjögren's syndrome in wild-type NOD mice in the long term.

INTERPRETATION

ICA69 is a new autoantigen in primary Sjögren's syndrome that has an important role in progression of disease and could be of diagnostic value. Immunotherapy of primary Sjögren's syndrome is promising, since autoimmunity in NOD mice with Sjögren's syndrome seems to be uniquely susceptible to such treatment even late in disease.

A study of doxorubicin loading onto and release from sulfopropyl dextran ion-exchange microspheres

The objective of this study was to investigate various factors that influence doxorubicin (Dox) loading onto and release from sulfopropyl dextran ion-exchange microspheres (MS), and to evaluate the anticancer activity of the released drug in vitro. Dox was incorporated into the MS by incubating the MS with aqueous solutions of Dox at room temperature. The drug release was carried out at 37 degrees C in aqueous solutions containing NaCl with or without CaCl2. The kinetics of drug absorption and release, the amount of Dox released, and the stability of Dox after loading, freeze-drying, and release were determined by spectrophotometry. The cytotoxicity of Dox (the original drug or that released from MS) against murine EMT6 breast cancer cells was assessed using a clonogenic assay. An increase in the MS to drug ratio resulted in a higher absorption rate and a higher fraction of the drug extracted from the solution. The release rate and the equilibrium fraction of Dox released increased with a decrease in the initial amount of Dox loaded or an increase in the salt concentration. The addition of divalent ions (Ca2+) promoted drug release compared to NaCl alone. The percent loss of colony forming ability of the cells, a measure of cytotoxicity of the released Dox, was the same as parent Dox solutions, indicating that the drug bioactivity was fully preserved after the drug loading and release cycle. This work demonstrated that various drug release rates were achieved by varying the drug loading and that the MS-delivered Dox was effective against the cancer cells in vitro.

Quantitative analysis of hepatitis C virus in peripheral blood and liver: replication detected only in liver

Prior studies seeking evidence of viral replication in peripheral lymphocytes of hepatitis C virus (HCV)-infected patients have yielded conflicting results. This study sought to quantitatively determine whether a permissive HCV cell interaction could be detected in leukocytes from infected patients. Peripheral leukocytes from chronically infected patients were purified and were tested for HCV RNA. The results show that virus load is highest in B cells. Other subsets of peripheral leukocytes consistently had very low levels of viral RNA or were negative. Negative-strand HCV was found only in hepatocytes. To determine whether HCV replication could be induced by activation, B cells from HCV-infected patients were stimulated in vitro. No HCV replicating in peripheral leukocytes was detected by a highly sensitive assay. If HCV replication occurs in the leukocyte subsets analyzed here, it is at extremely low levels or occurs under alternate physiological conditions.

Using the receiver operating characteristic curve to select pretreatment and pathologic predictors for early and late postprostatectomy PSA failure

OBJECTIVES

Pretreatment prostate-specific antigen (PSA), prostatectomy Gleason score, margin status, and pathologic T stage are known explanatory variables for the postprostatectomy PSA outcome. We used the receiver operating characteristic (ROC) curve to select those factors that were optimal for predicting early and late postoperative PSA failure.

METHODS

We designed and implemented a clinical outcome prediction expert that performs, assesses, and optimizes the actuarial prediction on individual cases. A postprostatectomy database of 1022 patients was divided into 60% for training and 40% for validation. The ROC areas of the predictors were calculated over a range of cutoff time from 24 to 60 months.

RESULTS

Multivariate pathologic T stage/prostatectomy Gleason score/margin status had the highest ROC area of 0.900. Patients with Stage T disease less than T3, negative surgical margins, and Gleason score of 6 or less had a 90% probability to be PSA failure free at 4 years versus 36% otherwise. The pathologic T stage/margin status accurately predicted PSA failure at 24 months or less after prostatectomy with an ROC area of 0.800. Lower risk patients (less than Stage T3, negative surgical margins) had a 94% probability to be PSA failure free at 2 years versus 46% otherwise.

CONCLUSIONS

A combination of actuarial analysis and ROC optimization accurately identified the individual patients at high risk of early and late postprostatectomy PSA failure.

Manganese intake and cholestatic jaundice in neonates receiving parenteral nutrition: a randomized controlled study

Infants requiring parenteral nutrition (n = 244) were randomized to receive either 1 (group 1, n = 121) or 0.0182 micromol/kg/d (group 2, n = 123) of manganese supplementation. The whole-blood manganese and serum direct bilirubin concentrations of the infants were monitored, as was the development of cholestasis (peak serum direct bilirubin concentration >50 micromol/L). Subgroup analysis was carried out on the data of 78 infants in group 1 and 82 in group 2 who had received manganese supplementation and more than three-quarters of their total daily fluid as parenteral nutrition for >14 d. Of all the infants randomized, the high manganese group (group 1) showed a trend towards developing higher peak whole-blood manganese concentration [group 1 versus group 2: median (interquartile range): 606.0 (421.0; 1005.0) vs 566.0 (336.0: 858.0); p=0.061] and higher peak serum direct bilirubin concentration [37.0 (10.5; 122.5) vs 19.0 (8.0; 112.5); p=0.153], but the differences between the 2 groups did not reach statistical significance. The 2 groups did not differ in terms of the occurrence of cholestasis during parenteral nutrition (63/121 vs 57/123; p=0.444). Subgroup analysis of infants who had received more than three-quarters of their total daily fluid as parenteral nutrition showed, however, that the high manganese group developed significantly higher whole-blood manganese concentration [743.5 (498.0; 1211.0) vs 587.0 (438.0; 982.0); p=0.037] and serum direct bilirubin concentration [84.0 (28.0; 170.0) vs 25.5 (9.0; 117.0): p < 0.001]. Although there was no significant difference in the occurrence of cholestasis (58/78 vs 49/82; p = 0.073), more infants in the high manganese group developed a more severe degree of direct hyperbilirubinaemia, with peak serum direct bilirubin >100 micromol/L (32/78 vs 20/82; p = 0.038).

CONCLUSION

We conclude that the pathogenesis of parenteral nutrition-related cholestasis is probably multifactorial, and that high manganese intake is a significant contributory factor.

Comparison of craniofacial skeletal characteristics of infants with bilateral choanal atresia and an age-matched normative population: computed tomography analysis

Choanal atresia (CA) results from the developmental failure of the posterior nasal cavity to communicate with the nasopharynx. Computed tomographic (CT) scanning is often used as a diagnostic tool for CA as it is able to provide information regarding the extent and type of atresia. Studies have used CT measurements to analyze the skeletal deformities of children with CA. Computed tomographic analysis of the complete craniofacial skeletal characteristics of children with CA has not been previously reported. This study analyzed the craniofacial skeletal characteristics of infants with bilateral choanal atresia (BCA) and compared them with age-matched standards. Eight patients with BCA under the age of 3 months were evaluated. Fourteen cranio-orbitozygomatic variables were used to represent the craniofacial skeletal configuration. The measurements from the control group were compared with the available values of age-matched normal controls. Statistically significant differences between the means of the sample group and control group were demonstrated in 10 of 14 variables. The sample group means were consistently smaller than the control group mean. Detailed knowledge of the underlying anatomy of infants with BCA will help in the development of treatment strategies and will provide data for evaluation of operative intervention on craniofacial growth.

Type I diabetes and multiple sclerosis patients target islet plus central nervous system autoantigens; nonimmunized nonobese diabetic mice can develop autoimmune encephalitis

Type I diabetes and multiple sclerosis (MS) are distinct autoimmune diseases where T cells target either islet or CNS self-proteins. Unexpectedly, we found that autoreactive T cells in diabetic patients, relatives with high diabetes risk, nonobese diabetic (NOD) mice, and MS patients routinely target classical islet as well as CNS autoantigens. The pathogenic potential of CNS autoreactivity was testable in NOD mice. Pertussis holotoxin, without additional Ags or adjuvants, allowed development of an NOD mouse-specific, autoimmune encephalitis with variable primary-progressive, monophasic, and relapsing-remitting courses. T cells from diabetic donors transferred CNS disease to pertussis toxin-pretreated NOD.scid mice, with accumulation of CD3/IFN-gamma transcripts in the brain. Diabetes and MS appear more closely related than previously perceived. NOD mouse-specific, autoimmune encephalitis provides a new MS model to identify factors that determine alternative disease outcomes in hosts with similar autoreactive T cell repertoires.

ROC optimization may improve risk stratification of prostate cancer patients

OBJECTIVES

Rational treatment decision requires accurate projection of the clinical course of a patient. Current methods in clinical outcome analysis mostly focus on population data. We investigated the applicability and optimization of the widely used actuarial method to project individual clinical outcomes.

METHODS

We designed and implemented a Clinical Outcome Prediction Expert (COPE) that performs, assesses, and optimizes actuarial prediction on individual cases. We analyzed a post-prostatectomy database, consisting of 1043 patients. Sixty percent of the database was used for training and 40% for validation. Stratified actuarial curves are used to project individual outcomes. The prostate-specific antigen (PSA) level, the Gleason score, and the clinical American Joint Commission on Cancer Staging T-stage before treatment were used as predictors. The area under the receiver operator characteristic (ROC) curve was used to measure predictive performance.

RESULTS

We obtained simple optimized stratification of pretreatment PSA level of 10 ng/mL or less, or more than 10 ng/mL; Gleason score of 6 or lower, or higher than 6; and clinical AJCC T-stage of T2a or lower, or higher. The optimized univariate risk scores were used to generate a multivariate score. After optimization, we found the higher risk group consisted of patients with PSA more than 10 ng/mL, or with PSA of 10 ng/mL or less and Gleason score higher than 6 and clinical AJCC T-stage higher than T2a. The optimized multivariate risk score has the highest ROC area of 0.77 among all predictors.

CONCLUSIONS

The best conditions to perform actuarial prediction on individual cases are not known a priori and require optimization. This study shows that ROC optimization simplifies risk stratification and may improve the accuracy of clinical outcome prediction.

Dissociation of G-protein alpha from rhabdomeric membranes decreases its interaction with rhodopsin and increases its degradation by calpain

Photoactivation of invertebrate rhodopsin activates a GTP-binding protein, Gq, which in turn activates a phospholipase C (PLC) enzyme. Gqalpha is a membrane-associated protein that is progressively released from the membrane by washing with buffers containing increasing concentrations of beta-mercaptoethanol (beta-ME). Isolated, soluble Gqalpha showed a decreased ability to be activated by rhodopsin but was more active in stimulating PLC when compared with the membrane-associated form of Gqalpha. The calcium-activated protease, calpain, selectively cleaved the soluble but not the membrane-bound form of Gqalpha. Calpain cleaved a small peptide from the amino-terminus of Gqalpha reducing the ability of the G-protein to bind GTP. The uncoupling of Gqalpha from rhodopsin and subsequent calcium-dependent proteolysis to further inactivate the G-protein may therefore be a regulatory mechanism of light adaptation in rhabdomeric photoreceptors.

Intracellular mechanisms regulating apoB-containing lipoprotein assembly and secretion in primary hamster hepatocytes

We studied the biogenesis of apolipoprotein B (apoB) in primary hepatocytes isolated from hamster liver, an animal model with striking resemblance to humans in lipoprotein metabolism. Hamster hepatocytes were found to assemble and secrete apoB-containing lipoproteins at a density of VLDL. Intracellular mechanisms of apoB biogenesis were investigated in both intact and permeabilized hamster hepatocytes. Translocational status of hamster apoB-100 was examined using trypsin protection assays in permeabilized cells as well as isolated microsomes which revealed that 27-42% of newly synthesized apoB was trypsin accessible as opposed to a control protein, transferrin, which was found to be essentially insensitive to exogenous trypsin. Subcellular fractionation of membrane and lumenal apoB pools indicated, however, that only a minor fraction of hamster apoB was associated with the microsomal membrane. Approximately 40% of newly synthesized apoB was found to be degraded post-translationally in a process sensitive to MG132. Immunoblotting analysis of apoB immunoprecipitates revealed ubiquitination of hamster apoB suggesting the involvement of the proteasome in its intracellular turnover. In addition to MG132, o-phenanthroline, a metalloprotease inhibitor, was also effective in stabilizing hamster apoB. Experiments in permeabilized hamster hepatocytes further confirmed post-translational instability of hamster apoB which was degraded over a 3-h chase generating proteolytic fragments including 167, 70, 57, and 46 kDa intermediates. Of these only the 70 kDa fragment was ALLN sensitive. Oleate treatment of hamster hepatocytes provided protection against intracellular apoB degradation, but did not stimulate its extracellular secretion. ApoB was assembled in the microsomal lumen into lipoprotein particles with densities of LDL and VLDL which were subsequently secreted as VLDL with a minor fraction forming HDL-like particles. In summary, hamster hepatocytes appear to efficiently assemble and secrete apoB-containing VLDL, although a significant pool of newly synthesized apoB is retained intracellularly and becomes sensitive to proteasome-mediated degradation as well as other proteases in the secretory pathway, generating specific degradative intermediates.

The effect of valsartan and captopril on lipid parameters in patients with type II diabetes mellitus and nephropathy

The study compared valsartan 80 mg or 160 mg o.d. with captopril 25 mg t.i.d. or placebo on plasma lipids in normotensive and treated hypertensive patients with type II diabetes and microalbuminuria. One hundred and twenty-two adult outpatients were randomised to receive either valsartan 80 mg or 160 mg, captopril 25 mg or placebo for 360 days. Changes from baseline to endpoint in plasma lipid parameters were measured. The primary criterion for tolerability was the incidence of adverse events. All treatment groups showed minor changes in lipid parameters. Triglyceride increased by 2.7% (valsartan 160 mg) to 9.1% (placebo). Total cholesterol decreased under valsartan 80 mg, while other groups showed increases of up to 0.031 mmol/l. Decreases in total cholesterol (p = 0.018), apolipoprotein B (p = 0.042) and apolipoprotein A1 (p = 0.025), were significant for the comparison of 80 mg valsartan and captopril. Valsartan 80 mg or 160 mg o.d. does not cause deleterious changes in the diabetic lipid profile and, unlike captopril, is not associated with dry cough.

Atorvastatin increases ecNOS levels in human platelets of hyperlipidemic subjects

BACKGROUND

The purpose of this study was to probe the pleiotrophic effects of Atorvastatin on intraplatelet-nitric oxide metabolism.

METHODS AND RESULTS

Hyperlipidemic subjects (n = 19) were treated for 1 month (following a 3-week washout) with either Atorvastatin or placebo in a double-blinded randomized (n = 2, crossover), placebo-controlled study. Changes in the levels of intraplatelet nitric oxide synthase, nitrotyrosine were correlated with cholesterol, LDL-C, HDL-C and triglyceride levels. These studies indicate that with atrovastatin ecNOS levels increased on average by approximately approximately 1.7-fold (paired t-test p = 0.009). Interestingly, levels of nitrotyrosylated platelet proteins, an indication of peroxynitrite damage, decreased as ecNOS levels increased in presence of the drug (paired t-test p = 0.33). Atorvastatin, at 10 mg per day, lowered cholesterol and LDL-C levels in all patients with the average lowering of approximately 21% and approximately 17% respectively. The effect on HDL was not significant whilst triglyceride levels were lowered by an average of approximately 18%.

CONCLUSIONS

This study adds to the volume of evidence that statins have beneficial effects other than lipid lowering. Here, Atorvastatin is shown to significantly elevate intraplatelet ecNOS levels in hyperlipidemic subjects without affecting iNOS expression. The net result of this would be the elevation of NO production which would promote platelet deaggregation and vasodilation.

Quantitative analysis of hepatitis C virus-specific CD8(+) T cells in peripheral blood and liver using peptide-MHC tetramers

It is believed that the hepatitis C virus (HCV)-specific CD8(+) cytotoxic T lymphocytes (CTLs) play a role in the development of liver cell injury and in the clearance of the virus. To develop a direct binding assay for HCV-specific CTLs, we generated two peptide-MHC tetramers by using the recombinant HLA A2.1 molecule and A2-restricted T cell epitopes of the HCV NS3 protein. With these reagents we are able to detect specific CD8(+) cells in the blood of 15 of 20 HLA-A2(+), HCV-infected patients, at a frequency ranging from 0.01% to 1.2% of peripheral CD8(+) T cells. Phenotypic analysis of these specific cells indicated that there is a significant variation in the expression of the CD45 isoforms and CD27 in different patients. A 6-hour incubation of one patient's blood with NS3 peptides resulted in the activation of the epitope-specific CD8(+) cells, as indicated by their expression of CD69 and IFN-gamma. We also detected NS3-specific CD8(+) T cells in the intrahepatic lymphocyte population isolated from liver biopsies of two HCV-infected patients. The frequency of these specific CD8(+) cells in the liver was 1-2%, at least 30-fold higher than in the peripheral blood. All of the intrahepatic NS3-specific CD8(+) T cells were CD69(+), suggesting that they were activated CTLs. Direct quantitation and characterization of HCV-specific CTLs should extend our understanding of the immunopathogenesis and the mechanism of clearance or persistence of HCV.

Replacements of single basic amino acids in the pleckstrin homology domain of phospholipase C-delta1 alter the ligand binding, phospholipase activity, and interaction with the plasma membrane

The pleckstrin homology (PH) domain of phosphatidylinositol-specific phospholipase C-delta1 (PLC-delta1) binds to both D-myo-inositol 1,4, 5-trisphosphate (Ins(1,4,5)P3) and phosphatidylinositol 4, 5-bisphosphate (PtdIns(4,5)P2) with high affinities. We have previously identified a region rich in basic amino acids within the PH domain critical for ligand binding (Yagisawa, H., Hirata, M., Kanematsu, T., Watanabe, Y., Ozaki, S., Sakuma, K., Tanaka, H., Yabuta, N., Kamata, H., Hirata, H., and Nojima, H. (1994) J. Biol. Chem. 269, 20179-20188; Hirata, M., Kanematsu, T., Sakuma, K., Koga, T., Watanabe, Y., Ozaki, S., and Yagisawa, H. (1994) Biochem. Biophys. Res. Commun. 205, 1563-1571). To investigate the role of these basic residues, we have performed site-directed mutagenesis replacing each of the basic amino acid in the N-terminal 60 residues of PLC-delta1 (Lys24, Lys30, Lys32, Arg37, Arg38, Arg40, Lys43, Lys49, Arg56, Lys57, and Arg60) with a neutral or an acidic amino acid. The effects of these mutations on the PH domain ligand binding properties and their consequence for substrate hydrolysis and membrane interactions of PLC-delta1 were analyzed using several assay systems. Analysis of [3H]-Ins(1,4,5)P3 binding, measurement of the binding affinities, and measurements of phospholipase activity using PtdIns(4,5)P2-containing phospholipid vesicles, demonstrated that residues Lys30, Lys32, Arg37, Arg38, Arg40, and Lys57 were required for these PLC-delta1 functions; in comparison, other mutations resulted in a moderate reduction. A subset of selected mutations was further analyzed for the enzyme activity toward substrate present in cellular membranes of permeabilized cells and for interaction with the plasma membrane after microinjection. These experiments demonstrated that mutations affecting ligand binding and PtdIns(4,5)P2 hydrolysis in phospholipid vesicles also resulted in reduction in the hydrolysis of cellular polyphosphoinositides and loss of membrane attachment. All residues (with the exception of the K43E substitution) found to be critical for the analyzed PLC-delta1 functions are present at the surface of the PH domain shown to contain the Ins(1,4,5)P3 binding pocket.

Regulation of inositol lipid-specific phospholipase cdelta by changes in Ca2+ ion concentrations

Studies of inositol lipid-specific phospholipase C (PLC) have elucidated the main regulatory pathways for PLCbeta and PLCgamma but the regulation of PLCdelta isoenzymes still remains obscure. Here we demonstrate that an increase in Ca2+ ion concentration within the physiological range (0.1-10 microM) is sufficient to stimulate PLCdelta1, but not PLCgamma1 and PLCbeta1, to hydrolyse cellular inositol lipids present in permeabilized cells. The activity of PLCdelta1 is further enhanced in the presence of phosphatidylinositol transfer protein (PI-TP). Both full activation by Ca2+ ions and stimulation in the presence of PI-TP require an intact PH domain involved in the membrane attachment of PLCdelta1. The physiological implication of this study is that PLCdelta1 could correspond to a previously uncharacterized PLC responsible for Ca2+ ion-stimulated inositol lipid hydrolysis observed in many cellular systems.

Loss of self-tolerance to ICA69 in nonobese diabetic mice

Islet cell antigen p69 (ICA69) is a target autoantigen in IDDM. Studies of T-cells from newly diabetic children suggested possible antigenic mimicry between human ICA69 (in particular the Tep69 T-cell epitope, aa 36-47) and the ABBOS region in bovine serum albumin (BSA; aa 152-169), one of several cow's milk proteins that evoke abnormal immunity in diabetes-prone hosts. We recently found the sequence of Tep69 regions to be identical in the four alternatively spliced human and rodent ICA69 isoforms. Immunization of nonobese diabetic (NOD) mice with BSA or ICA69 generates fully cross-reactive T-cell responses to both Tep69 and ABBOS as the immunodominant, naturally generated, and presented T-cell mimicry epitopes. Such responses are absent or weak in healthy strains of mice. NOD mouse recipients of adoptive spleen cell grafts from diabetic donors spontaneously generate easily detectable pools of T-cells specific for ICA69/BSA, as well as the unrelated GAD65. NOD mice injected neonatally with ABBOS or Tep69 show cross-tolerance, but ABBOS-induced tolerance is transient. Neonatal injection of Tep69 reduces disease incidence (23 vs. 68% IDDM, P < 0.02), while neonatal injection of ABBOS has little effect. In contrast, systemic immunization of young NOD females with ABBOS (but not Tep69) reduces the diabetes incidence and delays disease expression, with protected mice generating ABBOS-specific T-cell repertoires unable to recognize the Tep69 mimicry antigen. Our observations demonstrate a loss of self-tolerance to ICA69 in NOD mice, and they establish antigenic mimicry between the two T-cell epitopes in ICA69 and BSA. Further studies are necessary to understand the molecular basis of this mimicry and how either T-cell peptide can modify the disease course.

Molecular cloning of murine ICA69: diabetes-prone mice recognize the human autoimmune-epitope, Tep69, conserved in splice variants from both species

The islet cell antigen ICA69 is an autoimmune target in most patients with insulin-dependent diabetes. Understanding its role in diabetic autoimmunity would be facilitated by an animal model. We therefore cloned mouse ICA69. The different splice variants now identified conserve Tep69, the single T cell epitope recognized by patient T cells. We show that diabetes-prone NOD mice had Tep69-specific, autoreactive T cell repertoires and thus provide a relevant model for the study of ICA69's role in diabetic autoimmunity.

Crystal structure of a mammalian phosphoinositide-specific phospholipase C delta

Mammalian phosphoinositide-specific phospholipase C enzymes (PI-PLC) act as signal transducers that generate two second messengers, inositol-1,4,5-trisphosphate and diacylglycerol. The 2.4-A structure of phospholipase C delta 1 reveals a multidomain protein incorporating modules shared by many signalling proteins. The structure suggests a mechanism for membrane attachment and Ca2+-dependent hydrolysis of second-messenger precursors. The regulation and reversible membrane association of PI-PLC may serve as a model for understanding other multidomain enzymes involved in phospholipid signalling.

Strontium increases vertebral bone volume in rats at a low dose that does not induce detectable mineralization defect

Low doses of strontium and fluoride were shown to increase bone formation and trabecular bone density in rodents. To assess whether strontium or fluoride affect the quality of the mineral at doses known to increase bone density, we have determined the effects of low doses of strontium and fluoride on bone formation and bone mineral characteristics in rats. Adult rats were given strontium alone (0.20%), fluoride alone (1 mg/kg per day), or the combined treatment for 8 weeks. Strontium levels in serum and femur were similar in groups treated with strontium alone or in combination, being about 5% of calcium levels. Biochemical and neutron activation analyses in femur showed that calcium and magnesium contents did not differ in the four group of rats, suggesting that strontium was incorporated in the apatite lattice of the bone minerals in the strontium-treated rats. The mineralized bone volume was significantly increased by 17% in the strontium-treated group, by 20% in the fluoride-treated group, and by 19% in rats given with the combined treatment. This was associated with increased osteoid surface, osteoblast surface, and double tetracycline labeled surfaces in the strontium-treated and fluoride-treated groups, showing that the number of bone forming sites was increased. However, the mineral apposition rate, the osteoid thickness, and the mineralization lag time were similar in controls and treated groups, reflecting the lack of deleterious effects of low doses of strontium and fluoride on bone mineralization. The density fractionation analysis measured in the femur also showed that neither strontium, nor fluoride at the low doses used, significantly altered the mineralization profile. The results indicate that treatment with low doses of strontium or fluoride increase the number of bone forming sites and vertebral bone volume in rats, but does not have detectable adverse effects on the mineral profile, bone mineral chemistry or bone matrix mineralization.

Phospholipase C delta 1 requires a pleckstrin homology domain for interaction with the plasma membrane

The structural requirements of phospholipase C delta 1 for interaction with the plasma membrane were analysed by immunofluorescence after microinjection into living cells. Microinjection of deletion mutants revealed that the region required for membrane attachment and binding of inositol 1,4,5-trisphosphate in vitro corresponded to the pleckstrin homology domain, a structural module described in more than 90 proteins.

Biliary sludging in critically ill trauma patients

We used serial weekly ultrasonography to prospectively screen 19 critically ill trauma victims for the development of biliary sludge. Fourteen patients had sludge formation during their hospitalization. Sludge development was positively associated with increased transfusion requirements, but not with any other laboratory or clinical findings, including injury severity scores. The enteral feedings administered to most patients did not prevent sludge formation in the majority of cases; all five patients receiving total parenteral nutrition had sludge. Three patients had complications that could possibly be attributed to the sludge (one case of acalculous cholecystitis and two cases of mild pancreatitis). No such problems occurred in the five patients who did not have sludge. No long-term clinical problems related to sludge have occurred. We conclude that gallbladder sludge frequently develops in critically ill trauma patients and that sludge may be associated with pancreatobiliary complications.

T cells from children with IDDM are sensitized to bovine serum albumin

Epidemiological and experimental evidence suggested that denial of dietary cow milk protein early in life protects genetically susceptible children and animals from insulin-dependent diabetes (IDDM). Bovine serum albumin (BSA) was proposed as a candidate milk-borne mimicry antigen responsible for the diabetogenic cow milk effect. Elevated anti-BSA antibodies have been observed in patients and diabetic rodents, and these antibodies precipitate p69 from islet cell lysates. IDDM is a T cell mediated disorder but efforts to detect BSA-specific T cells in diabetic children have so far failed. We describe here a culture system which allowed the detection of BSA-specific T cells and we mapped this response to the ABBOS peptide (pre-BSA position 152-169) previously identified as a possible mimicry epitope. ABBOS-sensitized T cells were found in 28/31 children with recent onset IDDM but not in non-diabetic controls nor in children with SLE or JRA. T cell proliferative responses declined within the first few years of diabetes diagnosis. Although no effector cell role for BSA/ABBOS specific T lymphocytes has been demonstrated, the presence of BSA peptide-specific T cells strengthens the postulated link between a cow milk protein and IDDM.

A cell surface protein that binds avian hepatitis B virus particles

We have identified a 180-kDa cellular glycoprotein (gp180) that binds with high affinity to duck hepatitis B virus (DHBV) particles. The protein was detected by coprecipitating labeled duck hepatocyte proteins with virions or recombinant DHBV envelope proteins, using nonneutralizing monoclonal antibodies to the virion envelope. Binding of gp180 requires only the pre-S region of the viral large envelope protein, since recombinant fusion proteins bearing only this region efficiently coprecipitate gp180. The DHBV-gp180 interaction is blocked by two independent neutralizing monoclonal antibodies. The protein is found on both internal and surface membranes of the cell, and the species distribution of gp180 binding activity mirrors the known host range of DHBV infection. Functional gp180 is expressed in a wide variety of tissues in susceptible ducks.

Diethylstilbestrol liver carcinogenicity and modification of DNA in rats

Administration of diethylstilbestrol to female Sprague-Dawley rats at 10 mg/kg body weight daily by gavage for 1 year induced liver adenomas and carcinomas and pituitary adenomas. Using the 32P-postlabeling assay for DNA alterations, at 24 h after administration of a single dose of 100 mg/kg, modified bases were found.

Microalbuminuria and other cardiovascular risk factors in nondiabetic subjects

The association between urinary albumin:creatinine ratio and other cardiovascular risk factors such as age, blood pressure, obesity, glycemic indices, insulin and lipid profile was examined in a population in a Chinese community consisting of 795 men (mean age 35.8 +/- 8.8 yr) and 538 women (mean age 37.9 +/- 8.9 yr) with a normal glucose tolerance defined by WHO criteria. Men with a urinary albumin:creatinine ratio above the 90th percentile had higher systolic and diastolic blood pressures, fasting plasma glucose, 2-h glucose after a 75 g oral glucose load, and fasting serum insulin. Women with high urinary albumin:creatinine values had higher systolic and diastolic blood pressures, body mass index, waist-hip ratio, fasting insulin and triglycerides. Multivariate analysis showed that only systolic blood pressure and fasting glucose in men, and diastolic blood pressure and fasting insulin in women, independently contributed to urinary albumin:creatinine. When the effect of blood pressure was eliminated by excluding subjects with systolic blood pressure > 140 and diastolic > 90 mm Hg, only fasting insulin was associated with urinary albumin:creatinine in women. No associations were found for men. We conclude that microalbuminuria may be a marker for cardiovascular disease only because of its association with blood pressure in men, while in women, there is an additional independent association with fasting serum insulin.

Differential bacteriology in adenoid disease

In order to define the differential bacteriology in adenoid disease, adenoids were obtained from 10 children with adenoid hypertrophy and 29 children with chronic adenoiditis. The patients' ages ranged from 18 months to 13 years. After removal of the adenoids, the surface organisms were destroyed by alcohol and flame disinfection. One gram of tissue was sampled for aerobic and anaerobic culture. There was an average of 4.8 isolates per specimen, with 4.2 aerobes and 0.6 anaerobes. The most common isolates were: Haemophilus influenzae (84%), diphtheroids (66%), non-pathogenic Neisseria species (66%), alpha-hemolytic streptococci (64%) and non-hemolytic streptococci (59%). Anaerobes were present in 56% of all cases. The distribution of organisms was similar, regardless of clinical diagnosis. Only eight (21%) of the 39 cases had 'significant' (> or = 10(5) organisms/gm) colony counts. Our study detected no difference in either organism distribution or in total colony counts in chronic adenoiditis vs. adenoid hypertrophy.

Aerobic fitness and opioidergic inhibition of cardiovascular stress reactivity

The role of endogenous opioids in aerobic fitness-induced decrements in cardiovascular stress reactivity was examined by comparing the effects of opioid antagonism with naltrexone on responses to stress in young adults with high versus low levels of aerobic fitness. Two hundred forty subjects were given an activity questionnaire and males with the highest (Fit) and lowest (Nonfit) aerobic activity profiles were recruited for maximal oxygen consumption (VO2max) treadmill testing and psychological stress testing (final sample N = 28). Heart rate and blood pressures were measured during performance on a computer-controlled arithmetic task after pretreatment with either naltrexone (Trexan, DuPont) or a placebo. During placebo challenges, Fit subjects, compared with Nonfit, showed lower heart rate reactivity during stress and lower mean arterial blood pressures immediately before and during recovery from stress. Naltrexone eliminated these reactivity differences by increasing heart rate reactivity and raising mean arterial blood pressure in Fit subjects. These data suggest that aerobic fitness is associated with enhanced opioidergic inhibition of circulatory stress reactivity. Opioidergic modulatory effects on stress reactivity may comprise an important mechanism in fitness-associated risk reduction for cardiovascular disease.

Hepatitis C viremia in patients with hepatitis C virus infection

Sera from 103 patients were tested for hepatitis C virus RNA by nested polymerase chain reaction assay. Using primers from the highly conserved 5'-untranslated region, we detected hepatitis C virus RNA in 67 (88.2%) of 76 patients positive for antibody to hepatitis C virus by both second-generation and neutralization enzyme immunoassays. Hepatitis C virus RNA was detected in 93% of patients who had been infected for 10 yr or less and in 89% of those who had been infected for longer than 10 yr. Hepatitis C virus RNA was detected in all patients with chronic hepatitis, active cirrhosis or hepatocellular carcinoma and in 50% of those with nonspecific reactive hepatitis or inactive cirrhosis. Hepatitis C virus RNA was not detected in sera from 22 patients negative for antibody to hepatitis C virus or in 5 patients positive for antibody to hepatitis C virus by second-generation but not by neutralization enzyme immunoassay. Using primers from the less conserved nonstructural region 4, we detected hepatitis C virus RNA at a lower frequency, in 66% of patients who were positive for antibody to hepatitis C virus by both second-generation and neutralization enzyme immunoassays. The detection rate was higher in patients with frequent parenteral exposure. Our study showed that hepatitis C viremia can be detected in most patients with hepatitis C virus infection, including those with long-standing infection or advanced liver disease.