Autonomous functional domains of chemically synthesized human immunodeficiency virus tat trans-activator protein

HIV-1 encodes a potent trans-activator protein, tat, which is essential for viral gene expression. To study tat domains that function in trans-activation, we chemically synthesized the 86 amino acid tat protein (tat-86) and tat mutant peptides. Remarkably, tat-86 is rapidly taken up by cells, and produces a massive and specific stimulation of HIV-LTR-driven RNA synthesis. Mutant peptides of 21 to 41 amino acids exhibit significant activity. Only two regions are essential for trans-activation; we suggest that one represents an activation region and the other, a nucleic acid binding or nuclear targeting region. Amino acid substitutions within these regions greatly reduce trans-activation, demonstrating the functional significance of these domains. The N-terminal 37 amino acids and exon 2 are not essential. Thus, tat is similar to regulatory proteins of Ad E1A and BPV1 E5 oncogenes, requiring only small domains for autonomous function.

The UDP glycosyltransferase gene superfamily: recommended nomenclature update based on evolutionary divergence

This review represents an update of the nomenclature system for the UDP glucuronosyltransferase gene superfamily, which is based on divergent evolution. Since the previous review in 1991, sequences of many related UDP glycosyltransferases from lower organisms have appeared in the database, which expand our database considerably. At latest count, in animals, yeast, plants and bacteria there are 110 distinct cDNAs/genes whose protein products all contain a characteristic 'signature sequence' and, thus, are regarded as members of the same superfamily. Comparison of a relatedness tree of proteins leads to the definition of 33 families. It should be emphasized that at least six cloned UDP-GlcNAc N-acetylglucosaminyltransferases are not sufficiently homologous to be included as members of this superfamily and may represent an example of convergent evolution. For naming each gene, it is recommended that the root symbol UGT for human (Ugt for mouse and Drosophila), denoting 'UDP glycosyltransferase,' be followed by an Arabic number representing the family, a letter designating the subfamily, and an Arabic numeral denoting the individual gene within the family or subfamily, e.g. 'human UGT2B4' and 'mouse Ugt2b5'. We recommend the name 'UDP glycosyltransferase' because many of the proteins do not preferentially use UDP glucuronic acid, or their nucleotide sugar preference is unknown. Whereas the gene is italicized, the corresponding cDNA, transcript, protein and enzyme activity should be written with upper-case letters and without italics, e.g. 'human or mouse UGT1A1.' The UGT1 gene (spanning > 500 kb) contains at least 12 promoters/first exons, which can be spliced and joined with common exons 2 through 5, leading to different N-terminal halves but identical C-terminal halves of the gene products; in this scheme each first exon is regarded as a distinct gene (e.g. UGT1A1, UGT1A2, ... UGT1A12). When an orthologous gene between species cannot be identified with certainty, as occurs in the UGT2B subfamily, sequential naming of the genes is being carried out chronologically as they become characterized. We suggest that the Human Gene Nomenclature Guidelines (http://www.gene.acl.ac.uk/nomenclature/guidelines.html++ +) be used for all species other than the mouse and Drosophila. Thirty published human UGT1A1 mutant alleles responsible for clinical hyperbilirubinemias are listed herein, and given numbers following an asterisk (e.g. UGT1A1*30) consistent with the Human Gene Nomenclature Guidelines. It is anticipated that this UGT gene nomenclature system will require updating on a regular basis.

Amiodarone to prevent recurrence of atrial fibrillation. Canadian Trial of Atrial Fibrillation Investigators

BACKGROUND

The restoration and maintenance of sinus rhythm is a desirable goal in patients with atrial fibrillation, because the prevention of recurrences can improve cardiac function and relieve symptoms. Uncontrolled studies have suggested that amiodarone in low doses may be more effective and safer than other agents in preventing recurrence, but this agent has not been tested in a large, randomized trial.

METHODS

We undertook a prospective, multicenter trial to test the hypothesis that low doses of amiodarone would be more efficacious in preventing recurrent atrial fibrillation than therapy with sotalol or propafenone. We randomly assigned patients who had had at least one episode of atrial fibrillation within the previous six months to amiodarone or to sotalol or propafenone, given in an open-label fashion. The patients in the group assigned to sotalol or propafenone underwent a second randomization to determine whether they would receive sotalol or propafenone first; if the first drug was unsuccessful the second agent was prescribed. Loading doses of the drugs were administered and electrical cardioversion was performed (if necessary) within 21 days after randomization for all patients in both groups. The follow-up period began 21 days after randomization. The primary end point was the length of time to a first recurrence of atrial fibrillation.

RESULTS

Of the 403 patients in the study, 201 were assigned to amiodarone and 202 to either sotalol (101 patients) or propafenone (101 patients). After a mean of 16 months of follow-up, 71 of the patients who were assigned to amiodarone (35 percent) and 127 of those who were assigned to sotalol or propafenone (63 percent) had a recurrence of atrial fibrillation (P<0.001). Adverse events requiring the discontinuation of drug therapy occurred in 18 percent of the patients receiving amiodarone, as compared with 11 percent of those treated with sotalol or propafenone (P=0.06).

CONCLUSIONS

Amiodarone is more effective than sotalol or propafenone for the prevention of recurrences of atrial fibrillation.

Effect of granulocyte colony stimulating factor on neutropenia induced by cytotoxic chemotherapy

A phase I/II study of granulocyte colony stimulating factor (G-CSF) was undertaken in patients with advanced malignancy receiving melphalan to determine the granulocyte response, side-effects, and pharmacokinetics. Patients received doses of 1-60 micrograms/kg intravenously. There were 3 patients at each dose level. Before chemotherapy the immediate effect of G-CSF was a transient depression in circulating neutrophils followed by a dose-dependent rise. Neutrophil counts up to 80 X 10(9)/l were achieved. G-CSF administration following melphalan reduced the period of neutropenia caused by melphalan. G-CSF was well tolerated and the only clinical observation that appeared related to G-CSF administration was slight bone pain during some infusions. G-CSF was rapidly cleared from the blood with a mean half-life of 110 min for the second phase. Reductions in the number of days of neutropenia following cytotoxic chemotherapy may reduce the morbidity and mortality of chemotherapy.

Epstein-Barr virus-induced posttransplant lymphoproliferative disorders. ASTS/ASTP EBV-PTLD Task Force and The Mayo Clinic Organized International Consensus Development Meeting

Epstein-Barr virus-induced posttransplant lymphoproliferative disease (EBV-PTLD) continues to be a major complication after solid organ transplantation in high-risk patients. Despite the identification of risk factors that predispose patients to develop EBV-PTLD, limitations in our knowledge of its pathogenesis, variable criteria for establishing the diagnosis, and lack of randomized studies addressing the prevention and treatment of EBV-PTLD hamper the optimal management of this transplant complication. This review summarizes the current knowledge of EBV-PTLD and, as a result of two separate international meetings on this topic, and provides recommendations for future areas of study.

Intraperitoneal cisplatin with systemic thiosulfate protection

Seventeen patients with intraperitoneal tumors were treated by 4-hour intraperitoneal dialysis with cisplatin alone, or in combination with an intravenous neutralizing agent, sodium thiosulfate. Cisplatin alone, 90 mg/m2 body surface area intraperitoneally, produced nephrotoxicity. When intraperitoneal cisplatin therapy was combined with intravenous thiosulfate treatment, the dose of cisplatin could be escalated to 270 mg/m2 body surface area without causing an increase in serum creatinine levels or undue myelosuppression. Even at doses up to 270 mg/m2, no local toxicity occurred. The peak peritoneal concentration of free reactive cisplatin averaged 21-fold higher than the plasma level, and the area under the peritoneal cisplatin elimination curve averaged 12-fold more than the area under the plasma curve. Neither of these ratios varied significantly with cisplatin dose. Regression of intraperitoneal tumor masses was observed in patients with far-advanced ovarian carcinoma, mesothelioma, and malignant carcinoid.

An adenovirus E1a protein region required for transformation and transcriptional repression

The adenovirus E1a region encodes two closely related gene products: 243 and 289 amino acid phosphoproteins. These proteins differ in their primary sequence only by 46 amino acids unique to the 289 amino acid protein. By constructing single-base substitution mutants we localized two functional regions of these E1a proteins: one required for efficient transcriptional activation, another required for efficient transcriptional repression. The 289 amino acid protein contains both regions and appears to function primarily as a transcriptional activator. The 243 amino acid protein lacks the transcriptional activation domain and appears to function primarily as a transcriptional repressor. Mutations within a highly conserved region define a novel class of transformation-defective mutants. These mutant E1a proteins can still efficiently activate transcription of early viral and cellular genes but cannot repress transcription of target genes. The fact that viral transformation may require a transcriptional repression function provides new insights into the mechanism by which adenovirus transforms cells.

New-Onset Atrial Fibrillation

Background —Although sex differences in coronary artery disease have received considerable attention, few studies have dealt with sex differences in the most common sustained cardiac arrhythmia, atrial fibrillation (AF). Differences in presentation and clinical course may dictate different approaches to detection and management. We sought to examine sex-related differences in presentation, treatment, and outcome in patients presenting with new-onset AF.

Methods and Results —The Canadian Registry of Atrial Fibrillation (CARAF) enrolled subjects at the time of first ECG-confirmed diagnosis of AF. Participants were followed at 3 months, at 1 year, and annually thereafter. Treatment was at the discretion of the patients’ physicians and was not directed by CARAF investigators. Baseline and follow-up data collection included a detailed medical history, clinical, ECG, and echocardiographic measures, medication history, and therapeutic interventions. Three hundred thirty-nine women and 560 men were followed for 4.14±1.39 years. Compared with men, women were older at the time of presentation, more likely to seek medical advice because of symptoms, and experienced significantly higher heart rates during AF. Compared with older men, older women were half as likely to receive warfarin and twice as likely to receive acetylsalicylic acid. Compared with men on warfarin, women on warfarin were 3.35 times more likely to experience a major bleed.

Conclusions —Anticoagulants are underused in older women with AF relative to older men with AF, despite comparable risk profiles. Women receiving warfarin have a significantly higher risk of major bleeding, suggesting the need for careful monitoring of anticoagulant intensity in women.

Characteristic magnetic resonance imaging entheseal changes of knee synovitis in spondylarthropathy

OBJECTIVE

To use magnetic resonance imaging (MRI) in patients with rheumatoid arthritis (RA) and spondylarthropathy (SpA) to determine if the primary site of abnormality differs.

METHODS

Twenty patients with recent-onset knee effusion (10 with SpA and 10 with RA) were evaluated using fat-suppressed MRI. Knee joint effusion and synovitis were confirmed using ultrasonography. MRI scans were independently scored by 2 observers who were blinded to the patient's diagnosis.

RESULTS

All 10 of the SpA patients, but only 4 of the 10 RA patients, had focal peri-entheseal high signal (compatible with fluid or edema) outside the joint (P = 0.01). Six of the SpA patients had bone marrow edema that was maximal at entheseal insertions; in 4 cases this was multifocal. No RA patients showed such an abnormality (P = 0.01).

CONCLUSION

Prominent entheseal abnormalities on MRI are a consistent feature of new-onset synovitis in SpA, but are a minor feature of RA. This finding has important implications for the diagnosis, classification, and mechanisms of synovitis in patients with SpA.

Functional domains of adenovirus type 5 E1a proteins

Adenovirus E1a proteins function in transcriptional activation, transcriptional repression, cellular DNA synthesis induction, and cellular transformation. Here we examine the role of the previously undefined E1a region 1, the last of three conserved E1a regions to be characterized. Region 1 is required for transcriptional repression, transformation, and DNA synthesis induction, but not transcriptional activation. These results support our previous suggestion that transcriptional repression is the basis of E1a-mediated transformation. Two conserved regions (regions 1 and 2), present in both early E1a proteins, are essential for transcriptional repression, transformation, and induction of DNA synthesis. In contrast, mutagenesis suggests that transcriptional activation requires only 49 amino acids (region 3) unique to the 289 amino acid E1a protein. This we prove by demonstrating that a 49 amino acid region 3 synthetic peptide efficiently activates an E1a-inducible promoter. This peptide is the smallest known protein fragment functioning as a transcriptional activator.

Significance of ventricular arrhythmias initiated by programmed ventricular stimulation: the importance of the type of ventricular arrhythmia induced and the number of premature stimuli required

An increasing number of premature ventricular stimuli are being used during programmed stimulation of the heart in the investigation of patients with documented or suspected ventricular arrhythmias. To analyze the significance of the different types of ventricular arrhythmias that are initiated, we evaluated in a prospective study the effect of from one to four ventricular premature stimuli in 52 patients without (non-VT group) and 50 patients with (prior-VT group) documented ventricular tachycardia or ventricular fibrillation. More than half of the patients in the prior-VT group had coronary heart disease. In the majority of patients of the non-VT group the heart was normal. In 44 of the 50 patients in the prior-VT group the clinically documented ventricular arrhythmia was initiated by programmed ventricular stimulation of the heart. In 88% of these 44 patients, one or two ventricular premature beats were required to initiate the clinical arrhythmia. A ventricular arrhythmia could be initiated in 31 of the 52 patients in the non-VT group. The ventricular arrhythmias included nonsustained monomorphic ventricular tachycardia (two patients), six to 25 complexes of sustained polymorphic ventricular tachycardia (24 patients), and ventricular fibrillation (five patients). In 70% of patients in the non-VT group three or four ventricular premature beats were required to initiate the ventricular arrhythmia. Our results indicate that not only the number of extrastimuli required to initiate ventricular arrhythmias but also the type of ventricular arrhythmia initiated differed between the two groups of patients. Nonsustained polymorphic ventricular tachycardia and ventricular fibrillation are nonspecific responses to aggressive stimulation protocols.

Use of quantitative competitive PCR to measure Epstein-Barr virus genome load in the peripheral blood of pediatric transplant patients with lymphoproliferative disorders

A quantitative competitive PCR (QC-PCR) assay for Epstein-Barr virus (EBV) has been developed to provide accurate measurement of EBV genome load in pediatric transplant recipients at risk for developing posttransplant lymphoproliferative disorder (PTLD). The assay quantifies between 8 and 5,000 copies of the EBV genome in 10(5) lymphocytes after a 30-cycle amplification reaction. For 14 pediatric patients diagnosed with PTLD, the median EBV genome load was 4,000, and 13 of the 14 patients had values of >500 copies per 10(5) lymphocytes. Only 3 of 12 control transplant recipients not diagnosed with PTLD had detectable viral genome loads (median value, 40). This median was calculated by using the highest value obtained by PCR testing on each of these patients posttransplantation. PCR values of >500 copies per 10(5) lymphocytes appear to correlate with a diagnosis of PTLD. By a modified protocol, the EBV genome copy number in latently infected adults was estimated to be <0.1 copy per 10(5) lymphocytes.

Clinical evaluation of ZD6474, an orally active inhibitor of VEGF and EGF receptor signaling, in patients with solid, malignant tumors

BACKGROUND

ZD6474 selectively inhibits the tyrosine kinase activity of vascular endothelial growth factor receptor and epidermal growth factor receptor. The safety, tolerability and pharmacokinetics of ZD6474 were assessed in a phase I dose-escalation study of patients with advanced solid tumors.

PATIENTS AND METHODS

Adult patients with tumors refractory to standard treatments received once-daily oral ZD6474 (50-600 mg) in 28-day cycles, until disease progression or unacceptable toxicity was observed.

RESULTS

Seventy-seven patients were treated at doses of 50 mg (n=9), 100 mg (n=19), 200 mg (n=8), 300 mg (n=25), 500 mg (n=8), and 600 mg (n=8). Adverse events were generally mild, and the most common dose-limiting toxicities (DLT) were diarrhea (n=4), hypertension (n=4), and rash (n=3). The incidence of most adverse events appeared to be dose-dependant. In the 500 mg/day cohort, 3/8 patients experienced DLT and this dose was therefore considered to exceed the maximum tolerated dose. Pharmacokinetic analysis confirmed that ZD6474 was suitable for once-daily oral dosing.

CONCLUSIONS

Once-daily oral dosing of ZD6474 at 300 mg/day is generally well tolerated in patients with advanced solid tumors, and this dose is being investigated in phase II trials.

Familiarity and pop-out in visual search

In this paper, we report that when the low-level features of targets and distractors are held constant, visual search performance can be strongly influenced by familiarity. In the first condition, a [symbol: see text] was the target amid [symbol: see text]s as distractors, and vice versa. The response time increased steeply as a function of number of distractors (82 msec/item). When the same stimuli were rotated by 90 degrees (the second condition), however, they became familiar patterns--2 and 5--and gave rise to much shallower search functions (31 msec/item). In the third condition, when the search was for a familiar target, N (or Z), among unfamiliar distractors, [symbol: see text]s (or [symbol: see text]s), the slope was about 46 msec/item. In the last condition, when the search was for an unfamiliar target, [symbol: see text] (or [symbol: see text]), among familiar distractors, Ns (or Zs), parallel search functions were found with a slope of about 1.5 msec/item. These results show that familiarity speeds visual search and that it does so principally when the distractors, not the targets, are familiar.

Multiple functional domains of human transcription factor IIB: distinct interactions with two general transcription factors and RNA polymerase II

Transcription factor IIB (TFIIB) plays a pivotal role in the formation of transcription-competent initiation complexes. TFIIB was found to interact with the TATA-binding protein, the small subunit of TFIIF, and RNA polymerase II. These interactions require distinct domains in TFIIB. Using the gel mobility-shift assay, it was found that the amino terminus of TFIIB was necessary for the formation of complexes containing RNA polymerase II and TFIIF, whereas the carboxy-terminal domain, which is composed of two imperfect direct repeats and includes a putative amphipathic alpha-helix, was sufficient for the formation of complexes containing the TATA-binding protein and TFIIB (DB complex). Protein-protein interaction analyses demonstrate that the amphipathic alpha-helix in TFIIB is important for the interaction with the TATA-binding protein. Specific residues mapping to the carboxyl terminus of the second direct repeat were found to be crucial for the interaction of TFIIB and RNA polymerase II. The interaction with the small subunit of TFIIF was mapped to the amino terminus of TFIIB, which includes a zinc finger.

Histopathological biomarkers in estuarine fish species for the assessment of biological effects of contaminants

The increasing emphasis on the assessment and monitoring of estuarine ecosystems has highlighted the need to deploy appropriate biological indices for these locations. Fish diseases and histopathology, with a broad range of causes, are increasingly being used as indicators of environmental stress since they provide a definite biological end-point of historical exposure. This study reports on the histopathological alterations observed in selected organs and tissues of three species of estuarine fish (Platichthys flesus, Pomatoschistus minutus and Zoarces viviparus), captured from four British estuaries (the Tyne, Tees, Mersey and Alde), differently impacted by contaminants, including PAHs. A biannual sampling regime was used to identify the important seasonal variations that occur in terms of the observed biological effects. Inflammatory lesions and hepatocellular fibrillar inclusions attained their highest prevalence in P. flesus captured from the Tyne, Tees and Mersey. The presence of pre-neoplastic and neoplastic toxicopathic lesions was highest in P. flesus captured from these sites, when compared to fish from the Aide reference site. In particular, the prevalence of hepatic foci of cellular alteration (up to 43.3%) and hepatocellular adenoma (up to 10%) were highest in P. flesus captured from the Mersey estuary. Intersex (ovotestis) was only recorded in male P.flesus captured from the Mersey estuary (up to 8.3%) and from male Z. viviparous captured from the Tyne estuary (25%). Pathologies associated with the gill and the kidney were also most prevalent in fish captured from the Tyne, Tees and Mersey estuaries. This study has successfully applied histopathology to an estuarine monitoring program, both for the recording of toxicopathic lesions in the liver and other organs, and for the detection of the endpoint of endocrine disruption, intersex. As such, it provides a powerful integrative tool for the assessment of biological effects of contaminants in these environments.

Mutational analysis of HIV-1 Tat minimal domain peptides: identification of trans-dominant mutants that suppress HIV-LTR-driven gene expression

The HIV-1 Tat protein is a potent trans-activator essential for virus replication. We reported previously that HIV-1 Tat peptides containing residues 37-48 (mainly region II), a possible activating region, and residues 49-57 (region III), a nuclear targeting and putative nucleic acid binding region, possess minimal but distinct trans-activator activity. The presence of residues 58-72 (region IV) greatly enhances trans-activation. We postulate that Tat mutant peptides with an inactive region II and a functional region III can behave as dominant negative mutants. We synthesized minimal domain peptides containing single amino substitutions for amino acid residues within region II that are conserved among different HIV isolates. We identify four amino acid residues whose substitution within Tat minimal domain peptides leads to defects in transactivation. Some of these mutants are trans-dominant in several peptide backbones, since they strongly inhibit trans-activation by wild-type Tat protein added to cells or expressed from microinjected plasmid. Significantly, trans-activation of integrated HIV-LTRCAT is blocked by some trans-dominant mutant peptides. These results suggest an attractive approach for the development of an AIDS therapy.

Epstein-Barr virus infection and posttransplant lymphoproliferative disorder

Epstein-Barr virus (EBV) is an important pathogen in recipients of solid organ transplants (SOT). Infection with EBV manifests as a spectrum of diseases/malignancies ranging from asymptomatic viremia through infectious mononucleosis to posttransplant lymphoproliferative disorder (PTLD). EBV disease and its associated PTLD is more frequently seen when primary EBV infection occurs after transplant, a common scenario in pediatric SOT recipients. Intensity of immunosuppressive therapies also influences the risk for PTLD. The use of EBV viral load monitoring facilitates the diagnosis and management of EBV/PTLD as well as being used to inform preemptive therapy with reduction of immunosuppression, the most effective intervention for prevention of and treatment for PTLD. Other therapies, including the rituximab (anti-CD20 monoclonal antibody) and traditional chemotherapy, are also useful in the treatment of established PTLD. The future development of standards for management based on EBV viral load and routine monitoring of EBV-specific CTL responses promise further improvement in outcomes with EBV and PTLD.

The maximal sniff in the assessment of diaphragm function in man

We studied diaphragm function in a total of 64 normal subjects, who had no past or present respiratory or neuromuscular impairment. We measured transdiaphragmatic pressure (Pdi) during maximal sniffs and compared these values with Pdi during maximal static inspiratory efforts (PImax.). The range of Pdi during maximal sniffs (82-204 cm H2O) had better defined lower limits than Pdi during PImax. (16-164 cm H2O) and a higher mean value: mean +/- SD for maximal sniffs was 137 +/- 28 cm H2O and for PImax. was 90 +/- 37 cm H2O. The reproducibility of sniff Pdi was assessed in eight randomly chosen subjects over 3 days: the mean coefficient of variation was 7.2%. By comparison the coefficient of variation of Pdi during PImax. was 13.0% in seven subjects. The maximal sniff is a spontaneous manoeuvre, easily performed, repeatable without tiring, and reproducible. Its measurement provides a more reliable quantitative method for assessment of diaphragm strength, which has potential in clinical practice.

Risk of lung cancer associated with residential radon exposure in south-west England: a case-control study

Studies of underground miners occupationally exposed to radon have consistently demonstrated an increased risk of lung cancer in both smokers and non-smokers. Radon exposure also occurs elsewhere, especially in houses, and estimates based on the findings for miners suggest that residential radon is responsible for about one in 20 lung cancers in the UK, most being caused in combination with smoking. These calculations depend, however, on several assumptions and more direct evidence on the magnitude of the risk is needed. To obtain such evidence, a case-control study was carried out in south-west England in which 982 subjects with lung cancer and 3185 control subjects were interviewed. In addition, radon concentrations were measured at the addresses at which subjects had lived during the 30-year period ending 5 years before the interview. Lung cancer risk was examined in relation to residential radon concentration after taking into account the length of time that subjects had lived at each address and adjusting for age, sex, smoking status, county of residence and social class. The relative risk of lung cancer increased by 0.08 (95% CI -0.03, 0.20) per 100 Bq m(-3) increase in the observed time-weighted residential radon concentration. When the analysis was restricted to the 484 subjects with lung cancer and the 1637 control subjects with radon measurements available for the entire 30-year period of interest, the corresponding increase was somewhat higher at 0.14 per 100 Bq m(-3) (95% CI 0.01, 0.29), although the difference between this group and the remaining subjects was not statistically significant. When the analysis was repeated taking into account uncertainties in the assessment of radon exposure, the estimated increases in relative risk per 100 Bq m(-3) were larger, at 0.12 (95% CI -0.05, 0.33) when all subjects were included and 0.24 (95% CI -0.01, 0.56) when limited to subjects with radon measurements available for all 30 years. These results are consistent with those from studies of residential radon carried out in other countries in which data on individual subjects have been collected. The combined evidence suggests that the risk of lung cancer associated with residential radon exposure is about the size that has been postulated on the basis of the studies of miners exposed to radon.