Single-Molecule DNA Methylation Reveals Unique Epigenetic Identity Profiles of T Helper Cells

Both identity and plasticity of CD4 T helper (Th) cells are regulated in part by epigenetic mechanisms. However, a method that reliably and readily profiles DNA base modifications is still needed to finely study Th cell differentiation. Cytosine methylation in CpG context (5mCpG) and cytosine hydroxymethylation (5hmCpG) are DNA modifications that identify stable cell phenotypes, but their potential to characterize intermediate cell transitions has not yet been evaluated. To assess transition states in Th cells, we developed a method to profile Th cell identity using Cas9-targeted single-molecule nanopore sequencing. Targeting as few as 10 selected genomic loci, we were able to distinguish major in vitro polarized murine T cell subtypes, as well as intermediate phenotypes, by their native DNA 5mCpG patterns. Moreover, by using off-target sequences, we were able to infer transcription factor activities relevant to each cell subtype. Detection of 5mCpG and 5hmCpG was validated on intestinal Th17 cells escaping transforming growth factor β control, using single-molecule adaptive sampling. A total of 21 differentially methylated regions mapping to the 10-gene panel were identified in pathogenic Th17 cells relative to their nonpathogenic counterpart. Hence, our data highlight the potential to exploit native DNA methylation profiling to study physiological and pathological transition states of Th cells.

Regulatory T cell differentiation is controlled by αKG-induced alterations in mitochondrial metabolism and lipid homeostasis

Suppressive regulatory T cell (Treg) differentiation is controlled by diverse immunometabolic signaling pathways and intracellular metabolites. Here we show that cell-permeable α-ketoglutarate (αKG) alters the DNA methylation profile of naive CD4 T cells activated under Treg polarizing conditions, markedly attenuating FoxP3+ Treg differentiation and increasing inflammatory cytokines. Adoptive transfer of these T cells into tumor-bearing mice results in enhanced tumor infiltration, decreased FoxP3 expression, and delayed tumor growth. Mechanistically, αKG leads to an energetic state that is reprogrammed toward a mitochondrial metabolism, with increased oxidative phosphorylation and expression of mitochondrial complex enzymes. Furthermore, carbons from ectopic αKG are directly utilized in the generation of fatty acids, associated with lipidome remodeling and increased triacylglyceride stores. Notably, inhibition of either mitochondrial complex II or DGAT2-mediated triacylglyceride synthesis restores Treg differentiation and decreases the αKG-induced inflammatory phenotype. Thus, we identify a crosstalk between αKG, mitochondrial metabolism and triacylglyceride synthesis that controls Treg fate.

Pediatric "PSC-IBD": a descriptive report of associated inflammatory bowel disease among pediatric patients with psc

BACKGROUND

Inflammatory bowel disease (IBD) in adults with primary sclerosing cholangitis (PSC) is characterized by pancolonic involvement, a high frequency of rectal sparing, and an increased risk of pouchitis and colorectal neoplasia. The clinical features of IBD in pediatric patients with PSC have not been well described. The aim of this study was to characterize the frequency, clinical features, and natural history of IBD in pediatric patients diagnosed with PSC.

METHODS

A retrospective chart review was performed for all patients 18 years of age or younger diagnosed with PSC seen at the Mayo Clinic between 1975 and 1999. Endoscopic and histologic features and surgical and postsurgical outcomes were recorded.

RESULTS

Fifty-two children with PSC were identified. Forty-three patients (84%) were also diagnosed with IBD. In 36 of 43 cases, there was a sufficient diagnostic evaluation to allow a detailed review. Thirty-two of 36 patients (89%) had ulcerative colitis and 4 of 36 patients (11%) had Crohn's disease. In 4 of 36 patients (11%), IBD was asymptomatic. Although the most frequent endoscopic presentation of IBD was universal colitis, endoscopic rectal sparing was frequently noted (27% of colonoscopic studies). Of the four patients diagnosed with Crohn disease, in none did perianal, fistulizing, or stricturing disease develop. Proctocolectomy was performed in six patients (17%); three operations were performed for dysplasia. Pouchitis complicated four of the five ileal pouch-anal anastomoses procedures.

CONCLUSIONS

Among pediatric patients (1) PSC without IBD is uncommon; (2) asymptomatic IBD may be associated with PSC; (3) because the time to dysplasia may be accelerated, once the diagnosis of IBD is made in the setting of PSC, heightened endoscopic surveillance may be indicated; (4) pouchitis occurs frequently in these patients.

Hereditary pancreatitis. Historical perspectives

Clinically, hereditary pancreatitis was not distinguishable from any other cause of pancreatitis. But astute clinical observations demonstrated an evolution toward chronic pancreatitis that could develop into carcinoma in some patients. A chromosomal abnormality was identified on chromosome 7q35, and then three separate genetic abnormalities were identified. It is now understood that a defect in trypsinogen is at the basis of the anomaly, and further developments should help identify new therapeutic approaches.

JNK2 and IKKbeta are required for activating the innate response to viral infection

Viral infection or double-stranded (ds) RNA induce interferons (IFN) and other cytokines. Transcription factors mediating IFN induction are known, but the signaling pathways that regulate them are less clear. We now describe two such pathways. The first pathway leading to NF-kappaB depends on the dsRNA-responsive protein kinase (PKR), which in turn activates IKB kinase (IKK) through the IKKbeta subunit. The second viral-and dsRNA-responsive pathway is PKR independent and involves Jun kinase (JNK) activation leading to stimulation of AP-1. Both IKKbeta and JNK2 are essential for efficient induction of type I IFN and other cytokines in response to viral infection or dsRNA. This study establishes a general role for these kinases in activation of innate immune responses.

Antineutrophil cytoplasmic antibody subtypes in children and adolescents after ileal pouch-anal anastomosis for ulcerative colitis

BACKGROUND

Perinuclear antineutrophil cytoplasmic antibodies occur frequently in adult patients with chronic pouchitis after colectomy and ileal pouch-anal anastomosis for ulcerative colitis. The purpose of the study was to determine the prevalence of perinuclear antineutrophil cytoplasmic antibodies and cytoplasmic antineutrophil cytoplasmic antibody in children and adolescents who undergo colectomy and ileal pouch-anal anastomosis for ulcerative colitis and familial adenomatous polyposis.

METHODS

Five groups of children and adolescents (age, <20 years) were studied, with the following histories: acute pouchitis and history of ulcerative colitis; chronic pouchitis and history of ulcerative colitis; pouchitis with Crohn's disease features and a history of ulcerative colitis; no pouchitis and a history of ulcerative colitis; and familial adenomatous polyposis, with or without pouchitis. Antineutrophil cytoplasmic antibody levels and titers were detected in postoperative sera by enzyme-linked immunosorbent assay, and positive results were subtyped by indirect immunofluorescence.

RESULTS

The frequency of perinuclear antineutrophil cytoplasmic antibodies and cytoplasmic antineutrophil cytoplasmic antibody in patients with a history of ulcerative colitis were 67% and 15%, compared with a 0% presence in patients with familial adenomatous polyposis (p < 0.001). There was no significant correlation between the frequency of perinuclear antineutrophil cytoplasmic antibodies and ulcerative colitis patient subgroups (patients with and without pouchitis, 66% and 75%). Similarly, there was no significant correlation between the frequency of cytoplasmic antineutrophil cytoplasmic antibodies among ulcerative colitis patient subgroups (patients with and without pouchitis, 19% and 8%). The frequency of cytoplasmic antineutrophil cytoplasmic antibody in patients with Crohn's disease features (50%), was increased, but this difference was not significant.

CONCLUSIONS

There is a high frequency of perinuclear antineutrophil cytoplasmic antibodies in children and adolescents who undergo ileal pouch-anal anastomosis for ulcerative colitis, whether or not they have pouchitis. The frequency of cytoplasmic antineutrophil cytoplasmic antibody is lower in this patient population. Additional studies will be required to determine whether the presence of cytoplasmic antineutrophil cytoplasmic antibody is associated with the postoperative development of features of Crohn's disease.

Hereditary pancreatitis and the risk of pancreatic cancer. International Hereditary Pancreatitis Study Group

BACKGROUND

Hereditary pancreatitis is an autosomal-dominant disease, with a variable expression and an estimated penetrance of 80%. The gene for this disease has recently been mapped to chromosome 7q35, and the defect is believed to be caused by a mutation in the cationic trypsinogen gene. Acute attacks of abdominal pain begin early in life and the disease often progresses to chronic pancreatitis. Although the risk of pancreatic cancer is thought to be increased in more common types of chronic pancreatitis, the frequency of pancreatic cancer in the inherited type of pancreatitis is uncertain.

PURPOSE

The aim of this study was to assess the frequency of pancreatic cancer and other tumors in patients with hereditary form of pancreatitis.

METHODS

To determine the natural history of hereditary pancreatitis, we invited all members of the American Pancreatic Association and the International Association of Pancreatology to participate in a longitudinal study of this rare form of pancreatitis. The initial criteria for patient eligibility were as follows: early age (< or = 30 years) at onset of symptoms, positive family history, and absence of other causes. From April 1995 through February 1996, 37 physicians from 10 countries contributed medical records of 246 (125 males and 121 females) patients thought to have hereditary pancreatitis as the most likely diagnosis. This group included 218 patients where the diagnosis appeared to be highly probable and 28 additional patients where the diagnosis of hereditary pancreatitis was less certain: 25 patients who had relatively late onset of disease and a positive family history and three patients with onset of disease before age 30 years but with an uncertain family history. We reviewed all causes of death and compared the observed to the expected frequency of cancer in this historical cohort of patients with hereditary pancreatitis. The strength of the association between pancreatitis and pancreatic cancer was estimated by the standardized incidence ratio (SIR), which is the ratio of observed pancreatic cancer cases in the cohort to the expected pancreatic cancers in the background population, adjusted for age, sex, and country.

RESULTS

The mean age (+/- standard deviation [SD]) at onset of symptoms of pancreatitis was 13.9 +/- 12.2 years. Compared with an expected number of 0.150, eight pancreatic adenocarcinomas developed (mean age +/- SD at diagnosis of pancreatic cancer: 56.9 +/- 11.2 years) during 8531 person-years of follow-up, yielding an SIR of 53 (95% confidence interval [CI] = 23-105). The frequency of other tumors was not increased: SIR = 0.7 (95% CI = 0.3-1.6). Eight of 20 reported deaths in the cohort were from pancreatic cancer. Thirty members of the cohort have already been tested for the defective hereditary pancreatitis gene: all 30 carry a mutated copy of the trypsinogen gene. The transmission pattern of hereditary pancreatitis was known for 168 of 238 patients without pancreatic cancer and six of eight with pancreatic cancer. Ninety-nine of the 238 patients without pancreatic cancer and six of the patients with pancreatic cancer inherited the disease through the paternal side of the family. The estimated cumulative risk of pancreatic cancer to age 70 years in patients with hereditary pancreatitis approaches 40%. For patients with a paternal inheritance pattern, the cumulative risk of pancreatic cancer is approximately 75%.

CONCLUSIONS

Patients with hereditary pancreatitis have a high risk of pancreatic cancer several decades after the initial onset of pancreatitis. A paternal inheritance pattern increases the probability of developing pancreatic cancer.

Isolation and characterization of vesicular stomatitis virus PoIR revertants: polymerase readthrough of the leader-N gene junction is linked to an ATP-dependent function

The switch from transcription to replication of the VSV genome is coupled to assembly of nascent chains and involves an unspecified change in the P-L polymerase complex when it reaches the leader-N gene junction. PoIR VSV mutants, in contrast to wild-type virus, read through this first gene junction at high frequency without concurrent assembly, and they show altered ATP requirements for transcription in vitro. The mutation(s) responsible for the poIR phenotype segregates to the N-RNA template fraction. We report here that both poIR1 and poIR2 mutants display severe growth restriction in mouse L cells but not in BHK cells. Four of six poIR1 revertant viruses, originating from rare plaques on L cells, showed wild-type characteristics for growth, readthrough of leader-N gene junction, and ATP utilization, while two showed partial and quantitatively parallel coreversion of all properties. Sequence analysis of N and P genes of poIR mutants and revertants provided proof that a single mutation in the N protein, Arg179 to His, is responsible for the poIR phenotype. PoIR1, but not poIR2, also displayed a phenotypically silent GA-to-GG change in the N-P intergenic dinucleotide sequence Five of six revertants retained the poIR1 N protein mutation and showed no change in their P gene. We conclude that the L protein likely contains second-site suppressors of the poIR phenotype, and we propose that the switch from transcription to replication is modulated by an ATP-dependent interaction between the template-associated N protein and the L subunit of the P L polymerase complex.

Initiation of vesicular stomatitis virus mutant polR1 transcription internally at the N gene in vitro

The vesicular stomatitis virus (VSV) polymerase is thought to initiate transcription of its genome by first copying a small leader RNA complementary to the 3' end of the template. The polR VSV mutants, in contrast to wild-type virus, frequently read through the leader termination site during transcription in vitro. To shed light on polymerase termination and reinitiation events at the crucial leader-N gene junction, we employed RNase protection assays to precisely measure molar ratios of leader, N, and readthrough transcript accumulation in vitro. Wild-type virus synthesized essentially equimolar amounts of leader and N transcripts, but, unexpectedly, the polR1 mutant yielded about twice as much N mRNA as leader (ratio of 1.9 +/- 0.1). Primer extension assays ruled out an increase in abortive N transcript synthesis for polR1. Transcription entailed multiple rounds of synthesis, with transcript ratios remaining the same after 0.5 or 2 h of synthesis, ruling out a significant contribution from polymerases "pre-positioned" at the N gene. No significant degradation of either leader or N transcripts was observed after incubating purified products with virions. Our data lead us to conclude that transcription can initiate internally at the N gene, at least in the case of polR1 VSV. We propose, however, that productive internal initiation of transcription is a fundamental property of the VSV polymerase and that of related viruses. A model postulating two distinct polymerase complexes, one for leader synthesis and one for internal initiation, is presented.

Protein-losing enteropathy after the Fontan operation

Patients were observed after the Fontan operation to determine the frequency and severity of protein-losing enteropathy. A total of 427 patients who survived for 30 days after the Fontan operation, performed between 1973 and January 1987, were analyzed and, thus far, protein-losing enteropathy has developed in 47 of 427. The cumulative risk for the development of protein-losing enteropathy by 10 years was 13.4% among 30-day survivors, and 5-year survival after the diagnosis was 46%. Hemodynamic studies done coincident with the diagnosis of protein-losing enteropathy have shown increased systemic venous pressure, decreased cardiac index, increased pulmonary vascular resistance, and increased ventricular end-diastolic pressure. Medical management of protein-losing enteropathy was only partially successful. Statistical analysis has shown that factors related to protein-losing enteropathy were ventricular anatomy, increased preoperative ventricular end-diastolic pressure, longer operative bypass time, increased length of hospital stay, and postoperative renal failure. This study suggests that scrupulous selection of cases for the Fontan operation is mandatory and that certain perioperative factors may predispose to this serious complication of the Fontan procedure.

Constitutive phosphorylation of the vesicular stomatitis virus P protein modulates polymerase complex formation but is not essential for transcription or replication

As a subunit of both the P-L polymerase complex and the P-N assembly complex, the vesicular stomatitis virus (VSV) P protein plays a pivotal role in transcription and replication of the viral genome. Constitutive phosphorylation of this protein is currently thought to be essential for formation of the P-L complex. We recently identified the three relevant phosphate acceptor sites in the VSV Indiana serotype P protein (R. L. Jackson, D. Spadafora, and J. Perrault, Virology 214:189-197, 1995). We now report the effects of substituting Ala at these acceptor sites on transcription reconstitution in vitro and replication of defective interfering virus (DI) templates in vivo. The singly substituted S60A, T62A, and S64A mutants and the doubly substituted S60A/T62A and T62A/S64A mutants, all of which retain some constitutive phosphorylation, were nearly as active as the wild type in both assays. Surprisingly, the nonphosphorylated S60A/S64A protein was also active in transcription (> or = 28%)) and replication (> or = 50%) under optimal conditions. However, this mutant was much less active in in vitro transcription (< or = 5% of wild type) at low P concentrations (<27 nM). In addition, S60A/S64A required higher concentrations of L protein than did the wild type for optimal DI replication in vivo. DI replication efficiency and intracellular accumulation of L, P, and N proteins in the transfected system were very similar to those in VSV-infected cells. We conclude that P protein constitutive phosphorylation is not essential for VSV RNA synthesis per se but likely plays an important role in vivo in facilitating P multimerization and possibly P-L complex formation.

Measurement of heparin concentration in whole blood with the Hepcon/HMS device does not agree with laboratory determination of plasma heparin concentration using a chromogenic substrate for activated factor X

Measurement of circulating heparin concentration has been suggested to optimize anticoagulation during cardiopulmonary bypass. The Hepcon/HMS device (Medtronic HemoTec, Inc., Parker, Colo.) uses heparin/protamine titration to quantitatively determine heparin concentration. Extensive validation of this instrument is still lacking.

METHODS

Agreement between heparin concentrations measured by the Hepcon/HMS system and by laboratory determination was evaluated in 16 patients undergoing cardiac operations. For laboratory determinations, plasma heparin concentration was derived from the measure of anti-Xa activity by means of chromogenic substrate technique. The Hepcon/HMS instrument and cartridges measured whole blood heparin concentration. Samples were analyzed 5 minutes after administration of heparin, 15 and 30 minutes after the start of cardiopulmonary bypass, 5 minutes after aortic unclamping, at the end of cardiopulmonary bypass, and after administration of protamine. Data were plotted and interpreted according to the method of Bland and Altman: First, a difference less than 1.4 U/ml (i.e., +/- 0.7 U/ml) was chosen as acceptable, because it would not cause major difficulties in clinical interpretation; second, the difference between the two measurement techniques was plotted against the mean of the two measures.

RESULTS

The mean difference (bias) between heparin concentrations derived by the Hepcon/HMS device and those obtained by laboratory determination was as expected for measures performed on whole blood versus plasma (1.45 U/ml). Nevertheless, heparin concentrations derived by the Hepcon/HMS device may be as much as 2.76 U/ml above or 6.17 U/ml below the concentrations measured in the laboratory, differences well outside the predetermined limits of agreement and clearly unacceptable for clinical purposes.

CONCLUSION

We conclude that heparin concentrations determined with the Hepcon/HMS instrument do not agree with laboratory determination of heparin concentration. Monitoring of heparin concentrations during bypass with the Hepcon/HMS device cannot be recommended.

Stabilization of vesicular stomatitis virus L polymerase protein by P protein binding: a small deletion in the C-terminal domain of L abrogates binding

We showed previously that cells expressing the vesicular stomatitis virus (VSV) L polymerase gene via the vaccinia-T7 RNA polymerase system accumulated 2- to 5-fold more L protein when the P protein was coexpressed (Canter et al., 1993, Virology 194, 518-529). The results presented here provide an explanation for this phenomenon. Pulse-chase analysis revealed that L was unstable with a half-life of 3 to 6 hr if expressed in the absence of P protein, but was stable for at least 16 hr when coexpressed with a 10- to 15-fold molar excess of P. The P protein, in contrast, was stable under both conditions. Stabilization correlated with formation of a P:L polymerase complex evidenced both by coimmunoprecipitation and by glycerol gradient sedimentation analyses. A mutant L protein, lacking amino acids 1638 to 1673, was not stabilized by coexpression and showed no binding to P protein. Its anomalous sedimentation, however, suggested misfolding and/or aggregation as the cause for the failure to bind P. Transcription reconstitution in vitro, using extracts from cells expressing excess of P over L protein, strongly depended on coexpression of the proteins for optimal activity. We propose that the coexpression dependence for polymerase reconstitution documented here for VSV, as well as that reported previously for the Sendai paramyxovirus, reflects the protective effect of P protein on L protein stability.

Hierarchal constitutive phosphorylation of the vesicular stomatitis virus P protein and lack of effect on P1 to P2 conversion

In vitro reconstitution of a transcriptionally active VSV polymerase complex (P:L) reportedly requires phosphorylation of the N-terminal domain of P by CKII. Two constitutively phosphorylated sites have been implicated in this activation for both VSV Indiana and New Jersey serotype P proteins. We show here that, in contrast to New Jersey, the Indiana P protein is constitutively phosphorylated on three sites in vivo. The evidence rests on assessing the phosphorylation status of transfected P gene constructs containing all possible combinations of Ala substitutions at Ser60, Thr62, and Ser64. All mutants containing the T62A substitution showed a reduced level of phosphorylation and yielded no P-Thr. Surprisingly the S60A/S64A mutant behaved like the triple substitution and displayed no significant phosphorylation, while the S64A mutant yielded no P-Thr. Phosphorylation of Thr62 therefore depended on prior modification of Ser64. We also tested the ability of our mutant P proteins to convert to the more highly phosphorylated P2 species, a modification essential for transcription in the New Jersey serotype and thought to be carried out by an L-protein-associated kinase. All of our transfected mutant P proteins readily converted to P2 in the presence or absence of L cotransfection, and the latter had no significant effect on P phosphorylation. We conclude that VSV Indiana P protein differs in significant ways from New Jersey P. It is hierarchically and constitutively phosphorylated on a cluster of three sites, not two, suggesting that an additional kinase may be involved. Moreover, Indiana P1 to P2 conversion is independent of prior constitutive phosphorylation and does not require the presence of L protein.

Molecular characterization of Vibrio cholerae O139 isolates from Asia

In 1992, a serologically novel clone of Vibrio cholerae, designated O139, caused large epidemics of diarrhea in India and Bangladesh. To determine the extent of the spread of V. cholerae O139 worldwide, 484 V. cholerae non-O1 strains isolated from different patients with diarrhea in Thailand, Indonesia, the Philippines, and Peru in 1993 were tested for agglutination in O139 antisera. One hundred fifty-one of these 484 isolates were examined for genes encoding cholera toxin, zonula occlulans toxin, the repetitive sequence 1, and the toxin coregulated pilin A (the V. cholerae virulence gene complex). Thirty-three percent (122 of 364) of V. cholerae non-O1 strains isolated from different patients with diarrhea in Thailand agglutinated in O139 antisera. Ninety-eight percent (120 of 122) of V. cholerae O139 contained the V. cholerae virulence gene complex. None of the 104 V. cholerae non-O1 strains isolated from patients with diarrhea in Indonesia or the 14 strains from patients with diarrhea in the Philippines were serotype O139. Four different ribotypes were found in V. cholerae O139 isolated in Asia. Twenty-three (47%) of 49 Thai O139 strains examined were of different ribotypes than isolates from India and Bangladesh; V. cholerae strains that were not O1 or O139 that were isolated from flies and water in Thailand 11 years previously in 1981 contained the same V. cholerae virulence gene complex found in V. cholerae O1 and O139. This suggests that other unidentified virulence determinants are involved in V. cholerae O139 pathogenesis.

Hereditary pancreatitis

Hereditary pancreatitis is a clinical condition in which typical pancreatitis is associated with an inheritance pattern strongly suggestive of an autosomal dominant trait. Different variants have been described, some with aminoaciduria and some with ductal anomalies. Recurrent attacks are typical and lead to complications more often than in the idiopathic variety. Pancreatic enzyme supplements or antioxidants may help reduce the frequency and/or severity of attacks.

Hydromorphone patient-controlled analgesia (PCA) after coronary artery bypass surgery

We conducted a study to compare the effectiveness of patient-controlled analgesia (PCA) technique to conventional analgesic therapy (CAT) after coronary artery bypass graft (CABG). The PCA group received hydromorphone 0.1 mg.hr-1 basal infusion and bolus doses of 0.2 mg Q 5 min (maximum 1.2 mg.hr-1) while the CAT group received morphine 2.5 mg iv Q 30 min prn until extubation followed by prn meperidine 1 mg.kg-1 im Q 4 hr or acetaminophen 325 mg with codeine 30 mg po (1 or 2 tablets) when oral intake was possible. The degree of pain was assessed using a Visual Analogue Scale (VAS) starting after extubation and every 6-8 hr for the next 60 hr. Holter monitoring was initiated one hour after patient arrival in the Intensive Care Unit (ICU) and continued for 72 hr. Other measured variables were pulmonary function, sedation, side effects and total opioid requirements. Results show that the day-to-day VAS pain score decreased in the PCA group (P < 0.001) while it remained unchanged in CAT patients. The PCA patients had lower VAS pain scores at extubation (P < 0.05). During the third postoperative day, the PCA group had a lower VAS pain score, a lower incidence of severe pain defined as a score > 5 on the VAS scale, and a reduced incidence of myocardial ischaemia (P < 0.01). However, there was no difference in the duration, severity, area under the curve (AUC), or heart rate during ischaemic events. Postoperative pulmonary function was abnormal in both groups (NS) with minimal recovery by the fourth day.(ABSTRACT TRUNCATED AT 250 WORDS)

Enteric protein loss after the Fontan operation

OBJECTIVE

The current study was undertaken to assess the frequency of excessive enteric protein loss and protein-losing enteropathy in the relatively early period after the Fontan operation.

DESIGN

Protein excretion was determined in 26 of 27 consecutive patients who underwent the Fontan procedure between January and June 1990 at the Mayo Clinic.

MATERIAL AND METHODS

At two testing intervals during the first 4 months after the Fontan operation, alpha 1-antitrypsin clearance and fecal alpha 1-antitrypsin concentration studies were done.

RESULTS

All results were normal for the first postoperative test period (2 to 8 weeks). For the second study period, all 17 patients tested had normal alpha 1-antitrypsin clearances. One of the 17 patients had an appreciably increased fecal alpha 1-antitrypsin concentration and transient protein-losing enteropathy.

CONCLUSION

Excessive enteric protein loss and protein-losing enteropathy are relatively uncommon during the first 4 months after the Fontan operation.

A new approach for quality of life assessment in cardiac patients: rationale and validation of the Quality of Life Systemic Inventory

OBJECTIVE

To validate an interview-like questionnaire measuring quality of life, based on the subject's capacity to reach personal goals in different life domains.

DESIGN

One group repeated measures for test-retest reliability (two-week interval) and correlational approach for concurrent validity.

PARTICIPANTS

A total of 171 normal subjects (95 males and 76 females) was interviewed. Mean age was 43.6 years.

OUTCOME MEASURES

The Quality of Life Systemic Inventory (QLSI), the Beck Depression Inventory, the State-Trait Anxiety Inventory, the Marlowe and Crowne Social Desirability Scale, the Buss and Durkee Hostility Inventory, the Carver and Sheerer self-efficacy scale and the Derogatis Stress Profile were used.

RESULTS

The quality of life score (a gap score representing the difference between a subject's actual state and personal goal) has a high test-retest reliability of 0.838. The two other scores (goal and potential for conflict) also have good test-retest reliability: 0.858 for both. Intercorrelations between scores are low-gap-goal, 0.293; gap-conflict, 0.172; and goal-conflict, 0.115--suggesting their distinctiveness. Correlations between scores and social desirability are also low-gap, 0.106; conflict, -0.024; and goal, -0.128. Finally, correlations with other psychological variables such as depression, anxiety, self-efficacy and stress are moderate to low, showing that the questionnaire measures dimensions different from these variables.

CONCLUSIONS

The QLSI has good test-retest reliability, and scores are not much influenced by social desirability despite the fact that the test is used in an interview setting. The questionnaire may be administered in small groups or face-to-face situations. It yields a wealth of clinical information and is easily used in research. Furthermore, patients much prefer this interactive exchange to the long self-administered questionnaires.

Low-dose aprotinin infusion is not clinically useful to reduce bleeding and transfusion of homologous blood products in high-risk cardiac surgical patients

A high-dose regimen of aprotinin 5-6 million KIU is effective in reducing bleeding and the need for homologous blood products (HBP) associated with cardiopulmonary bypass (CPB). These high doses aim at achieving plasmin and plasma kallikrein concentrations which in vitro are inhibitory but, theoretically, smaller doses could suffice in vivo. Also, aprotinin is an expensive drug, so efficiency requires using the smallest effective dose. Therefore, the efficacy of prophylactic aprotinin 1 million KIU (the maximal dose approved currently) was evaluated in a patient population at high risk of bleeding and of being transfused. Forty-one patients undergoing reoperation or a complex surgical procedure were included in a prospective, randomized, placebo-controlled, double-blind study. Before skin incision, a bolus of 200,000 KIU aprotinin was administered in 20 min, followed by an infusion of 100,000 KIU.hr-1 over eight hours. Control patients received an equal volume of saline. Dryness of the operative field, chest drainage, transfusion of HBP, haemoglobin concentrations, and coagulation variables (including bleeding time) were compared. There were no differences between aprotinin and placebo-treated patients for all clinical and laboratory variables. The apparent ineffectiveness of aprotinin may be explained by the use of an insufficient dose, by a different protocol of administration (e.g., no bolus in CPB prime), or by the inability of aprotinin to decrease bleeding and transfusions any further. Also, the number of patients studied does not exclude the possibility of a Type II error.(ABSTRACT TRUNCATED AT 250 WORDS)

Amrinone, in combination with norepinephrine, is an effective first-line drug for difficult separation from cardiopulmonary bypass

A crucial element for weaning patients from cardiopulmonary bypass (CPB) rests on the selection of an appropriate therapeutic regimen. Amrinone, a phosphodiesterase III inhibitor, combines inotropic support with pulmonary and systemic vasodilatation, without increasing heart rate (HR) or myocardial oxygen consumption. These characteristics should be useful in the failing heart during weaning from CPB. Nineteen patients were included in this prospective, open-labelled, phase IV study when systolic blood pressure (DPAP) > 15 mmHg or central venous pressure (CVP) > 15 mmHg, during progressive separation from CPB. At that moment, CPB flow was increased to alleviate heart failure and amrinone administered as a bolus (0.75 mg.kg-1) followed by an infusion (10 micrograms.kg-1.min-1). Weaning from CPB was then resumed and haemodynamic variables (SBP, DPAP, CVP and HR) were compared with those measured at CPB flow when failure had first occurred. Failure to wean from CPB occurred at 57 +/- 28% of full pump flow. After the amrinone bolus, DPAP and CVP decreased by 20% and 21% respectively. Subsequently, 16 patients required the infusion of norepinephrine (4-8 micrograms.min-1) to maintain a SBP > 80 mmHg. Heart rate remained unchanged after the bolus of amrinone, after separation from CPB, and no arrhythmias were noted. Successful weaning from CPB was possible 12 +/- 8 min after the amrinone bolus. Weaning resulted in a cardiac index similar to that measured pre-bypass. Amrinone is rapidly effective during weaning from CPB and, in combination with norepinephrine, provides the necessary inotropic support during this unstable period.

Faithful and efficient in vitro reconstitution of vesicular stomatitis virus transcription using plasmid-encoded L and P proteins

We demonstrate here that plasmid-expressed polymerase proteins of a negative-strand RNA virus can faithfully reconstitute all aspects of the transcription process carried out by virion cores in vitro. The assay is based on adding purified nucleocapsid templates of vesicular stomatitis virus to extracts of cells expressing L and P viral polymerase proteins via the vaccinia-T7 RNA polymerase recombinant virus. No significant differences were seen between the native virion core reaction and the optimally reconstituted system including ratio of transcripts produced, polyadenylation, net synthesis per template, amounts of polymerase proteins and template, and competence to initiate infection in vivo. Reconstitution was not dependent on cotranslation of P and L proteins in the same cell since nearly as much activity was obtained by mixing extracts expressing each protein individually. Cotransfection with P plasmid, however, stimulated L protein accumulation two- to fivefold relative to transfection with L alone. Surprisingly, deleting a small region in the C-terminal half of the L polymerase protein (amino acids 1638 to 1673) abolished transcription as well as stimulation by P coexpression. Since the polymerase domain of L presumably lies in the N-terminal half of the protein, these results suggest that the putative nucleotide-binding motif in the deleted segment may be involved in an accessory function essential for the transcription process.

Multicenter trial of d-alpha-tocopheryl polyethylene glycol 1000 succinate for treatment of vitamin E deficiency in children with chronic cholestasis

BACKGROUND

Malabsorption and deficiency of vitamin E causing neurological degeneration are common consequences of chronic childhood cholestatic liver disease. The objective of this study was to determine the long-term efficacy and safety of d-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS) in correcting vitamin E deficiency in children with chronic cholestasis who were unresponsive to other forms of oral vitamin E.

METHODS

Sixty vitamin E-deficient children with chronic cholestasis unresponsive to 70-212 IU.kg-1.day-1 of oral vitamin E were entered into a trial at eight centers in the United States. After initial evaluation, treatment was started with 25 IU.kg-1.day-1 of TPGS. Vitamin E status, neurological function quantitated by a specific scoring system, and clinical and biochemical parameters were monitored during therapy.

RESULTS

All children responded to TPGS with normalization of vitamin E status. Neurological function, which had deteriorated before entry in the trial, improved in 25 patients, stabilized in 27, and worsened in only 2 after a mean of 2.5 years of therapy. No adverse effects were observed.

CONCLUSIONS

TPGS (20-25 IU.kg-1.day-1) appears to be a safe and effective form of vitamin E for reversing or preventing vitamin E deficiency during chronic childhood cholestasis.

Long-term follow-up of young patients with chronic hereditary or idiopathic pancreatitis

We conducted a retrospective study of patients younger than 20 years of age who had a diagnosis of chronic pancreatitis and underwent assessment at the Mayo Clinic between 1960 and 1990. Those with a known etiologic factor for the pancreatitis (such as a virus, trauma, alcohol, or hyperlipidemia) were excluded from the study. We compared the clinical course of the 42 patients who had hereditary pancreatitis (HP)--defined as at least two family members affected by the condition--with that of the 28 patients who had idiopathic pancreatitis (IP). The mean age at initial assessment was 7 years for those with HP and 12 years for those with IP. All patients in both groups had abdominal pain. Vomiting was more frequent in patients with HP than in those with IP; otherwise the initial symptoms were similar in both groups. Patients with HP, however, had more complications, including pseudocysts (seven patients), steatorrhea (four), ascites (three), portal hypertension (two), and diabetes (one), than did patients with IP (one each had diabetes, steatorrhea, and a pseudocyst). Complications or pain necessitated surgical intervention in 23 of 42 patients with HP versus 4 of 28 patients with IP. Overall in comparison with IP, HP seems to be a more severe variant of chronic pancreatitis, inasmuch as it is associated with more frequent complications and need for surgical intervention.

Assessment of the arterial tonometer (N-CAT) for the continuous blood pressure measurement in rapid atrial fibrillation

The N-CAT is a newly developed arterial tonometer (TBP) able to determine systolic, diastolic and mean arterial blood pressures continuously and noninvasively. The aim of this study was to evaluate the accuracy and reliability of TBP relative to directly measured invasive blood pressure (IBP) in ten haemodynamically stable postoperative cardiac patients who were in rapid atrial fibrillation (HR > or = 100 bpm). There were differences between TBP and IBP for systolic (-1.7 mmHg) and diastolic (+0.9 mmHg) values but not for the mean arterial blood pressures. The N-CAT was able to follow blood pressure changes closely and demonstrated an average systolic, diastolic and mean bias (+/-SD) of -1.71 +/- 4.6, 0.99 +/- 4.6 and 0.33 +/- 4.2 mmHg, respectively. Although these biases are within the required standards for equivalency for noninvasive blood pressure to invasively determined blood pressure, approximately 20% of the readings were > +/- 10 mmHg while only 5% were > +/- 20 mmHg. Moreover, there were occasional discrepancies of sufficient magnitude and duration which may limit the clinical usefulness of the N-CAT in patients in whom continuous and accurate blood pressure measurement is required.

A simple classification of the risk in cardiac surgery: the first decade

Since 1980, the operative risk in all our cardiac surgical patients has been assessed before surgery. In light of reports of changes in cardiac surgical populations, we reexamined our practice and risk classification. The purpose of this study was to compare the surgery performed, the characteristics of the patients operated upon and the hospital mortality in our institution in two epochs ten years apart. In 1989-90, the 2029 consecutive cardiac surgical patients who had the same operations as the 500 patients of a 1980 study in our institution were prospectively stratified using our risk classification based on the number of risk factors (RFs) present: normal-risk patient = no RF, increased risk = 1 RF, high risk > or = 2 RFs. These two cohorts of patients were compared. From 1980 to 1990, the proportion of high-risk patients tripled whereas the proportion of normal-risk patients diminished by one third and the proportion of increased risk remained unchanged. The incidence of the following RFs increased: poor left ventricular function, advanced age, emergency surgery, reoperation and other systemic disorders. In coronary artery surgery patients, the incidence of unstable angina/recent myocardial infarction and of obesity also increased. In noncoronary artery surgery patients, the incidence of heart failure increased while obesity remained unchanged. The difference in hospital mortality among the three risk classes was significant within both study periods. The mortality in each risk class and total mortality did not change between 1980 and 1990.(ABSTRACT TRUNCATED AT 250 WORDS)

Measurement of colonic tissue cyclosporine concentration in children with severe ulcerative colitis

Recent studies suggest that cyclosporine may be an alternative to colectomy in children with severe ulcerative colitis who fail traditional therapy with bowel rest and high-dose corticosteroids. We report the clinical course of two such children. Patient 1 received oral cyclosporine at 15 mg/kg/day for 1 week followed by 8 mg/kg/day for 6 weeks. Clinical remission occurred within 5 days and has been sustained for 24 weeks after azathioprine was substituted for cyclosporine. Patient 2 received oral cyclosporine at 7-8 mg/kg/day for 7 days after which colectomy was performed due to lack of clinical improvement. Blood cyclosporine levels for patient 1 ranged from 95 to 406 ng/ml and for patient 2 from 36 to 65 ng/ml. Sigmoid colonic tissue cyclosporine concentrations for patients 1 and 2 were 10,058 and 3,205 ng/g, respectively. The patient who responded had significantly higher blood and colonic tissue cyclosporine concentrations than the patient who did not respond. Further studies with larger numbers of patients are needed to determine if there is a correlation between blood and colonic tissue cyclosporine concentrations and clinical response.

Stepwise phosphorylation of vesicular stomatitis virus P protein by virion-associated kinases and uncoupling of second step from in vitro transcription

Transcription-competent cores of vesicular stomatitis virus (VSV) contain two tightly bound protein kinase activities capable of phosphorylating the viral P protein (Beckes and Perrault, Virology 184, 383-386, 1991). We examined here the specificity of these kinases for the P protein substrate and their activity during the in vitro transcription process. Conditions favoring the VSVK1 kinase activity resulted in phosphorylation of the P1 species predominantly whereas conditions favoring VSVK2, or transcription conditions, led to an increase in the proportion of the faster migrating P2 and P3 species. A minimum of 2 mol phosphate/mol P protein was incorporated in 1 hr under optimal transcription conditions. Pulse-chase experiments revealed that the VSVK2 activity converted phosphorylated P1 to P2/P3 species. Most or all of the sites modified by VSVK1 (serines only) mapped to the 78 amino acid-long N-terminal fragment of the P protein; additional serine acceptor sites of undetermined location were also phosphorylated under VSVK2 conditions. Pretreatment of virion cores with 5'-p-fluorosulfonylbenzoyl adenosine had little or no effect on P1 phosphorylation but inhibited P1 to P2/P3 conversion nearly completely, with no effect on subsequent transcription. Likewise, the addition of cell extracts had relatively little effect on P1 phosphorylation but strongly inhibited the appearance of P2/P3, without affecting concurrent transcription. We conclude that phosphorylation of the P protein during transcription in vitro is a two-step process carried out by two distinct kinase activities, but only the first step may be essential for viral mRNA synthesis.

Surgical therapy and long-term follow-up of childhood hereditary pancreatitis

Treatment and a 15-year follow-up survey of 42 patients with hereditary pancreatitis (HP) were compared with 28 patients with idiopathic recurrent pancreatitis (RP) of childhood. There was no difference between the two groups except for pancreatic ductal dilatation and stones in patients with HP. Longitudinal pancreaticojejunostomy (20) or resection and drainage procedures (7) were more commonly required in patients with HP than RP (55% v 14%). There was no surgical mortality. Postoperatively, immediate and complete relief of symptoms was obtained in 43% of patients with HP and 25% of patients with RP. In the remainder, recurrent attacks of pancreatitis abated over 2 years such that 81% of the surgical patients were in good or excellent health. Occasional symptoms persisted in 52% of HP patients and 25% of RP patients. Of the 20 patients with HP or RP undergoing longitudinal pancreaticojejunostomy extending from the head to the tail, 75% were symptom-free on follow-up. However, 3 of 6 patients with poor results had also undergone this procedure. At long-term follow-up of patients who did not undergo operation, 75% of HP patients and 90% of RP patients reported excellent or good health despite the persistent symptoms in 68% and 42%, respectively. Surgery for childhood HP is dependent on the complications present. Longitudinal pancreaticojejunostomy is beneficial for ductal dilatation and associated pseudocysts or pancreatic ascites. The performance of this procedure in the absence of consistent pancreatic duct dilatation will give poor results. Patients without ductal dilatation and the majority of patients with RP may eventually lead near normal lives without resorting to surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Two distinct protein kinase activities in vesicular stomatitis virions phosphorylate the NS transcription factor

Two vesicular stomatitis virion proteins, NS and M, are phosphorylated in vivo before packaging and in vitro during the transcription process carried out with disrupted virions. Phosphorylation of NS is thought to be essential for transcription but which of the many acceptor sites is or are involved in this function and which protein kinase(s) is responsible still need to be resolved. We recently reported that the virion-associated kinase which modifies M protein is most likely a different enzyme than that phosphorylating NS (Beckes et al., Virology 169, 161-171 1989). Here we present additional evidence for the presence of distinct enzymes modifying M vs NS substrates and also show that at least two distinct kinase activities modify NS protein. Each of the three activities displayed different optimum reaction conditions, phosphate donor preferences, and sensitivity to inhibition by N-ethylmaleimide.

6-mercaptopurine therapy in selected cases of corticosteroid-dependent Crohn's disease

Nineteen patients (12 children and 7 adults) with severe Crohn's disease, all of whom were dependent on corticosteroids, were treated with 6-mercaptopurine. All patients received a daily dose of 6-mercaptopurine of 50 mg; in two pediatric patients with a poor response after 2 months, the dosage was increased to 75 mg/day. A complete or partial response to 6-mercaptopurine therapy was noted in 47% of patients, and therapy failed in 53%. The age of the patients, prior resection, or initial symptoms did not influence the response. The clinical response was better in male than in female patients and in patients with involvement of both the small intestine and the colon than in those with only enteritis. 6-Mercaptopurine is a possible alternative to long-term corticosteroid therapy or surgical treatment in selected patients with severe Crohn's disease.

The stratification of cardiac surgical procedures according to use of blood products: a retrospective analysis of 1480 cases

The use of blood products in 1480 consecutive cases of adult cardiac surgical procedures over a period of 15 mth was studied retrospectively using the database of the Department of Anaesthesia of the Institut de Cardiologie de Montréal. Use of blood products was compared in patients having (1) coronary artery bypass grafting, (2) valvular surgery, (3) or a combination of 1 and 2. First operations were compared with reoperations. Overall, the use of homologous blood products was greatest in patients of Group 3, intermediate in patients of Group 2, and smallest in patients of Group 1. Reoperations were associated with an increase in intraoperative transfusion of packed red blood cells, but postoperative chest drainage was similar to first operations. When all blood products (packed red blood cells, fresh frozen plasma and platelets) were taken into consideration, patients undergoing primary CABG or valve surgery were the least exposed to homologous blood donors (five and six units transfused respectively). Repeat CABG was associated with an intermediate exposure to homologous blood products (eight units). Finally, primary and repeat combined procedures, and repeat valve surgery were associated with the greatest exposure to foreign blood products (10, 13 and 10 units respectively). The data presented in this study provide a rational basis for stratification of procedures according to the expected use of blood products, particularly in view of future studies which may be planned to examine the efficiency of blood conservation strategies.

The surgical management of children with ulcerative colitis. The old vs. the new

The authors' experience with children who have chronic ulcerative colitis was reviewed to compare their current surgical approach (ileoanal anastomosis) with earlier methods of management. Between 1960 and 1984, 137 children with chronic ulcerative colitis underwent surgery (mean duration of follow-up, 7.1 years). In 91 patients, the procedures were a total proctocolectomy with ileostomy or Kock pouch (66) or a lesser colectomy with either an ileostomy (16) or an ileorectal anastomosis (9) (group I). Forty-six patients underwent an ileoanal anastomosis procedure (group II). Children in group I were more likely to have significant preoperative loss of weight, a debilitated condition, and malnutrition. Urgent or emergency surgical intervention was required in 25 percent of patients in group I but in only 4 percent of patients in group II. Trends included 1) a younger age at operation in group II, 2) a higher mortality in group I (7.7 percent) than group II (0 percent), and 3) a higher perioperative mortality with emergency operations (23 percent) than elective procedures (1.6 percent). In group I, 98 percent of patients had an abdominal ostomy, but no patients in group II had an abdominal ostomy. The children with an ileoanal anastomosis had an average of 4.8 stools during waking hours and 1.3 stools each night. On the basis of this experience, the authors recommend use of the ileoanal anastomosis procedure in the surgical treatment of chronic ulcerative colitis in children.

Long-term follow-up of the ileoanal anastomosis in children and young adults

The purpose of this study was to carry out a long-term study of the ileoanal anastomosis (IAA) in children and young adults, comparing the straight IAA to the J pouch. One hundred twenty-one young people who had undergone IAA were studied, with 114 available for long-term follow-up. One hundred one were 18 years and under. Forty-nine patients had a straight IAA and 72 had a J-pouch reservoir. There were no deaths. After surgery, three children had intraabdominal sepsis and one had pelvic sepsis, but it did not lead to excision of the IAA. The mean stool frequency in all 114 patients was 5.0 +/- 2.5 per day and 1.2 +/- 1.1 at night. The mean number of stools for the straight IAA was 6 per day and 2.1 at night. The mean number of stools for the straight IAA with balloon dilations was 5.8 per day and 1.2 at night, and for the J pouch it was 4 per day and 1 at night. Patients with both the J pouch and straight IAA had good to excellent sensation, with patients with the J pouch always able to distinguish flatus from stool in 87% of patients and almost always in 13%. Daytime continence was very good in both groups. Moderate nighttime loss of stool occurred in 10 patients, 6 with a straight IAA and 4 with a J pouch. Ninety-five percent of the 114 patients were satisfied or very satisfied, with most children with a J pouch very satisfied. The J pouch remains the procedure of choice in young people.

Heterotopic gastric mucosa in the common bile duct

Gastric heterotopia within the biliary system is rare and is generally an incidental finding. Only a few patients have biliary symptoms specifically attributable to heterotopia. A unique case of symptomatic gastric heterotopia of the common bile duct is presented and the literature reviewed.

Two domains distantly related to protein-tyrosine kinases in the vesicular stomatitis virus polymerase

We have carried out an exhaustive search for amino acid sequence similarities between vesicular stomatitis virus (VSV) proteins and database entries. Unexpectedly, we found that the L polymerase protein contains two blocks of sequence (residues 725-1102 and 1291-1671) with distant but statistically significant similarity to the catalytic domain of tyrosine-specific protein kinases. The first kinase-like region is most similar to members of the Abl subfamily, Fes and Fps (26.6% and 27.3% identity, respectively), whereas the second region is closest to members of the platelet-derived growth factor receptor (PDGFR) subfamily, PDGFR and Kit (30.4% and 25.9% identity, respectively). Multiple alignment of the catalytic domain of these kinases to all three rhabdovirus L protein sequences available (VSV Indiana, VSV New Jersey, and rabies) revealed that the polymerases contain many but not all residues well conserved in the protein kinase family. Similarity was highest for VSV Indiana and lowest for rabies. We conclude that the kinase-like regions in the rhabdoviral L proteins are probably very distantly related to the protein kinase family. The similarities could either reflect contemporary protein kinase activity or represent some other function(s) associated with these large multifunctional polymerase proteins. Our findings also shed new light on questions of the origins and evolution of RNA viruses.

Redistributive properties of the vesicular stomatitis virus polymerase

The template for transcription of the vesicular stomatitis virus (VSV) genome consists of a negative-strand RNA (approximately 11 kb) tightly associated with approximately 1250 copies of the nucleocapsid or N protein (N-RNA template). The interaction between the virion-associated polymerase and this template was probed with a novel assay using purified N-RNA complexes added to detergent-disrupted uv-irradiated standard virions or unirradiated defective interfering (DI) particles. In contrast to the well-known stability of assembled cellular transcription complexes, the VSV polymerase copied exogenously added templates efficiently and yielded products indistinguishable from control virus transcription. Addition of uv-irradiated N-RNA templates to unirradiated virus effectively competed for transcription of endogenous template indicating that most or all of the polymerase can freely redistribute. Furthermore preincubation of virus and added templates at high ionic strength to solubilize L and NS polymerase proteins did not release additional active enzyme for redistribution. Pretranscription of virus also had little or no effect on redistributed activity indicating that polymerase complexes are capable of multiple rounds of synthesis beginning at the 3' end promoter. Unexpectedly, titration with saturating amounts of added N-RNA showed that active polymerase complexes are only in slight excess relative to template in standard or DI particles despite the large surplus of packaged L and NS polypeptides. Moreover, added standard virus templates competed equally well for the redistributing polymerase from DI particles or standard virus indicating no significant polymerase-binding preference for interfering templates. These findings bear important implications regarding mechanisms of VSV transcription and replication.

Phosphorylation of vesicular stomatitis virus M protein: evidence for a second virion-associated protein serine kinase activity

The vesicular stomatitis virus (VSV) NS and M proteins are not only phosphorylated in vivo but are also further modified by the virion-associated protein kinase(s) concomitantly with the in vitro transcription process. Although NS phosphorylation is necessary for this transcription, no function has yet been ascribed for M protein phosphorylation. We show here that all phosphates added to M protein in vitro mapped to the trypsin-sensitive N-terminal basic domain (residues 1-43). The major site(s) (approximately 93%) corresponded to one or more of three serine residues within the first 17 amino acids. Nearly 1 mol phosphate/mol protein was added in vitro under optimal conditions suggesting that only one of these three candidate serine residues corresponds to the major site. This same M protein domain is thought to play an important role in virus RNA synthesis by inhibiting transcription. We show here that in vitro phosphorylation did not appear to affect this function. Two critical serine residues in the VSV NS protein were previously reported to be phosphorylated during in vitro transcription (D. Chattopadhyay and A. K. Banerjee, 1987, Cell 49, 407-414). The sequence flanking these NS serines is very acidic while that of all three candidate phosphoserines in the M protein is very basic. We therefore predict that at least two distinct serine-specific kinase activities are packaged in virions, one specific for M and one specific for NS.

Altered ATP utilization by the poIR mutants of vesicular stomatitis virus maps to the N-RNA template

In a continuation of previous efforts to study the modified ATP requirements for RNA synthesis by poIR mutants of vesicular stomatitis virus (VSV), we have used a novel reconstitution assay to show that it is the template moiety of the mutants, not the polymerase proteins, which governs both the increased utilization of the ATP analog, beta, gamma-imido ATP (AMP-PMP), and the loss of a positive cooperativity-like response to varying ATP concentrations. Assays utilized uv-irradiated virus as a source of polymerase proteins and purified N-RNA as templates. Homologous and heterologous transcriptase reactions were carried out with wild-type (wt) virus and each of the two independently isolated poIR mutants. We show that in the presence of wt N-RNA template, substitution of AMP-PNP for ATP resulted in only approximately 5% of control RNA synthesis regardless of which source of polymerase was used. Furthermore, all reactions containing wt N-RNA template responded to varying ATP concentrations with a concave, upward-shaped Lineweaver-Burke plot generally indicative of positive cooperativity effects. In contrast, all reactions which utilized N-RNA templates from the poIR mutants showed an increased utilization of AMP-PNP (greater than 20%) and a more characteristic Michaelis-Menten response to changing ATP concentrations. These findings strongly support the notion that the template-associated nucleocapsid protein modulates the utilization of an ATP site which is directly or indirectly involved in VSV RNA synthesis.

Surreptitious use of salicylates: a cause of chronic recurrent gastroduodenal ulcers

We describe five patients who had chronic recurrent gastroduodenal ulcers and pain, intestinal obstruction, bleeding, or a combination of these symptoms. Four patients required surgical intervention because of a poor response to medical therapy. The ulcers recurred in all patients, despite evidence of achlorhydria in two of them. Although the patients denied the use of salicylates, all of them had therapeutic blood levels of salicylates. A salicylate level should be determined in patients with severe ulcer disease that is resistant to medical therapy or that is recurrent after appropriate surgical therapy when the presence of hypergastrinemia or hyperchlorhydria has been definitely excluded. A low serum level of uric acid can also be a clue to the abuse of salicylates.