hTid-1, a human DnaJ protein, modulates the interferon signaling pathway.

The Jak family of protein-tyrosine kinases are crucial for the signaling of a large number of different polypeptide ligands, including the interferons, many cytokines, erythropoietin, and growth factors. Through their interaction with receptors, the Jaks initiate a signaling cascade resulting in the activation of gene transcription and ultimately a cellular response to various ligands. In addition to their role in cellular signaling, alteration of Jak activity has been implicated in several disease states. In identifying Jak2-interacting proteins with the yeast two-hybrid system, we cloned the human homologue of the Drosophila melanogaster tumor suppressor gene lethal () tumorous imaginal discs, which encodes the protein Tid56. Drosophila Tid56 and its human homologue hTid-1 represent members of the DnaJ family of molecular chaperones. The TID1 gene encodes two splice variants hTid-1(S) and hTid-1(L). We confirmed the interaction between Jak2 and hTid-1(S) or hTid-1(L) by immunoprecipitation from COS-1 cells expressing these proteins. The interaction between endogenous hTid-1 and Jak2 was shown in HEp2 cells. We further showed that hTid-1 interacts with the human interferon-gamma (Hu-IFN-gamma) receptor subunit IFN-gamma R2. In addition, using a chimeric construct where the extracellular domain of IFN-gamma R2 was fused to the kinase domain of Jak2, we showed that hTid-1 binds more efficiently to the chimera with an active kinase domain than to a similar construct with an inactive kinase domain. Additionally, the data demonstrate that hTid-1 isoforms as well as Jak2 interact with Hsp70/Hsc70 in vivo, and the interaction between Hsp70/Hsc70 and hTid-1 is reduced after IFN-gamma treatment. Furthermore, both hTid-1(S) and hTid-1(L) can modulate IFN-gamma-mediated transcriptional activity.

Factors that predict incomplete colonoscopy: thinner is not always better.

OBJECTIVE: The aim of this study was to determine whether anatomic factors such as body mass index (BMI) impacts the success rate of cecal intubation during colonoscopy. METHODS: We retrospectively reviewed the cecal intubation rate of 2000 colonoscopies performed at our institution from March 1997 to March 1999. The analysis sample was composed of charts for all incomplete procedures and a sample (23%) of complete examinations that were randomly selected. Data collected included age, gender, height, weight, bowel habits, abdominal surgery, psychiatric medication use, the presence of diverticular disease, amount of sedation administered, and location and reason for halting the examination. Patients were divided by BMI: thin (BMI < or = 22.1), average weight (BMI > 22.1-25.0), overweight (BMI = 25.1-29.9), and obese (BMI > 30). RESULTS: Colonoscopies in women had a lower adjusted completion rate (94.8%) than in men (98.2%) (p < 0.005). A low BMI in women was predictive of an incomplete examination (p < 0.001). Factors that did not predict incomplete examinations in women included age and previous hysterectomy. The small number of male patients with an incomplete examination (n = 16) precluded accurate identification of any factors. CONCLUSIONS: Women with a low BMI (especially < 22) were more likely to have an incomplete procedure. This finding may have implications for colorectal cancer screening in female patients.

PROXIMITY: an update and expansion of the PROXTIME computer program.

A new program, called PROXIMITY, was created as a tool for proximity calculation and to update and expand upon Kirste and Monge's (1983) PROXTIME program. The purpose of PROXIMITY is to calculate the fluctuating proximity between individuals within organizations. PROXIMITY provides output for three types of relationships: (1) an overall organizational proximity, (2) pairwise proximity between individuals, and (3) individual proximity to multiple others. PROXIMITY also updates some of PROXTIME's features such as the computer platform, the type of data the program can handle, and the form of output available.

Hsl7p, the yeast homologue of human JBP1, is a protein methyltransferase.

The yeast protein Hsl7p is a homologue of Janus kinase binding protein 1, JBP1, a newly characterized protein methyltransferase. In this report, Hsl7p also is shown to be a methyltransferase. It can be crosslinked to [(3)H]S-adenosylmethionine and exhibits in vitro protein methylation activity. Calf histones H2A and H4 and bovine myelin basic protein were methylated by Hsl7p, whereas histones H1, H2B, and H3 and bovine cytochrome c were not. We demonstrated that JBP1 can complement Saccharomyces cerevisiae with a disrupted HSL7 gene as judged by a reduction of the elongated bud phenotype, and a point mutation in the JBP1 S-adenosylmethionine consensus binding sequence eliminated all complementation by JBP1. Therefore, we conclude the yeast protein Hsl7p is a sequence and functional homologue of JBP1. These data provide evidence for an intricate link between protein methylation and macroscopic changes in yeast morphology.

Behavioral interventions for lung cancer-related breathlessness.

PURPOSE: The purpose of this report is to present behavioral interventions to assist persons with lung cancer in the management of feelings of breathlessness and, thus, also to enhance their quality of life. OVERVIEW: Breathlessness is a serious symptom that adversely affects the quality of life of persons with lung cancer. A review of the literature points to the value of exercises in assisting patients to breathe more effectively and to manage related anxiety. However, the professional literature frequently does not describe these basic interventions in enough detail to enable oncology professionals to learn them. Instructional materials, found in the popular wellness and self-help literature, are included in this article to more easily facilitate acquisition of these skills. Interventions described include exercises that enhance the use of the diaphragm when breathing and those that help to alter the breathing rhythm and to exhale more effectively. CLINICAL IMPLICATIONS: All oncology professionals should be aware of the importance of breathlessness as a problem that diminishes the quality of life for patients with lung cancer. Addressing breathlessness through the use of psychosocially oriented behavioral interventions can act as an adjunct to the medical management of this debilitating symptom.

The human homologue of the yeast proteins Skb1 and Hsl7p interacts with Jak kinases and contains protein methyltransferase activity.

To expand our understanding of the role of Jak2 in cellular signaling, we used the yeast two-hybrid system to identify Jak2-interacting proteins. One of the clones identified represents a human homologue of the Schizosaccaromyces pombe Shk1 kinase-binding protein 1, Skb1, and the protein encoded by the Saccharomyces cerevisiae HSL7 (histone synthetic lethal 7) gene. Since no functional motifs or biochemical activities for this protein or its homologues had been reported, we sought to determine a biochemical function for this human protein. We demonstrate that this protein is a protein methyltransferase. This protein, designated JBP1 (Jak-binding protein 1), and its homologues contain motifs conserved among protein methyltransferases. JBP1 can be cross-linked to radiolabeled S-adenosylmethionine (AdoMet) and methylates histones (H2A and H4) and myelin basic protein. Mutants containing substitutions within a conserved region likely to be involved in AdoMet binding exhibit little or no activity. We mapped the JBP1 gene to chromosome 14q11.2-21. In addition, JBP1 co-immunoprecipitates with several other proteins, which serve as methyl group acceptors and which may represent physiological targets of this methyltransferase. Messenger RNA for JBP1 is widely expressed in human tissues. We have also identified and sequenced a homologue of JBP1 in Drosophila melanogaster. This report provides a clue to the biochemical function for this conserved protein and suggests that protein methyltransferases may have a role in cellular signaling.

Endoscopic ultrasound in restaging of esophageal cancer after neoadjuvant chemoradiation.

BACKGROUND: Endoscopic ultrasound (EUS) is established as the most accurate method currently available for determining the depth of primary cancer invasion (T stage). Standard EUS criteria may not be accurate in assessing depth of cancer invasion and nodal status after patients have received chemotherapy or radiotherapy. METHODS: We conducted a prospective study to determine whether EUS estimation of tumor size could be used to assess response to preoperative chemoradiation. Using EUS, TNM stage was assessed in 31 patients (22 men, 9 women; mean age 62 years) with cancer of esophagus or cardia (19 adenocarcinoma, 12 squamous cell cancer) before initiation of combined radiation and 5-fluorouracil/cisplatin (and/or carboplatinum) chemotherapy. The cross-sectional area of the tumor in the transverse plane at the location where the tumor had maximal thickness was calculated to estimate tumor size. EUS staging and measurement of maximal cross-sectional area were repeated at completion of chemoradiation just before surgery. Response to preoperative chemoradiation was defined as 50% reduction in maximal cross-sectional area. Surgical staging was compared between responders and nonresponders. RESULTS: Eight patients who did not undergo surgery were excluded from analysis. EUST stage in the remaining 23 patients before therapy was as follows: 3 T2, 16 T3, and 4 T4. After chemoradiation, EUS T staging was changed in 6 patients (3 T4 downstaged to T3, 2 T3 downstaged to T2, and 1 T3 downstaged to T1). At surgical pathological examination, 3 patients had no residual tumor in the esophagus (T0), 5 had T1, 3 had T2, 10 had T3, and 2 had T4 tumors. EUS T staging accuracy after adjuvant therapy was only 43%. Maximal cross-sectional area decreased from a mean of 5.5 +/- 2.4 to 1.6 +/- 0.9 cm2 in responders, whereas maximal cross-sectional area went from 7.0 +/- 3.0 to 5.4 +/- 2.2 cm2 in nonresponders (p = 0.009). Ten of thirteen patients with at least a 50% reduction in maximal cross-sectional area (responders) had T0, T1, or T2 tumors at surgery, whereas 9 of 10 nonresponders had T3 or T4 tumors at surgery (p = 0.001). CONCLUSIONS: (1) Standard EUS staging criteria are not accurate after neoadjuvant chemoradiation, (2) reduction in maximal cross-sectional area of tumor appears to be a more useful measure for assessing response of esophageal cancer to preoperative chemoradiation, and (3) responders have an increased likelihood of downstaging at surgery than nonresponders.

Enteroscopy for the initial evaluation of iron deficiency.

BACKGROUND: Occult gastrointestinal blood loss is generally investigated with colonoscopy and esophagogastroduodenoscopy in patients with iron-deficiency anemia. The aim of this study was to prospectively measure the additional diagnostic yield of examining the jejunum at the time of upper endoscopy in patients with iron-deficiency anemia. METHODS: Asymptomatic patients with newly diagnosed iron-deficiency anemia who had no identifiable source of blood loss at colonoscopy underwent standard esophagogastroduodenoscopy with the Olympus SIF100L enteroscope followed by overtube-assisted enteroscopy. Upper tract and jejunal sources of blood loss were noted. Biopsy samples from the small bowel were taken when a bleeding lesion was not identified. RESULTS: Thirty-one consecutive patients (13 men, mean age 71) with no gastrointestinal symptomatology were studied. Eleven patients (35%) had a bleeding source that required only esophagogastroduodenoscopy for identification; 8 patients (26%) had a source only in the jejunum; 2 patients (6%) (one with sprue) had a source in upper tract as well as jejunum. The enteroscopy was rated as causing minimal or mild discomfort in 25 of 31 patients (81%). Using Medicare reimbursement figures, a strategy of performing esophagogastroduodenoscopy first would have cost $656 per patient, whereas the strategy of performing esophagogastroduodenoscopy with enteroscopy as the initial test in all patients costs $467 per patient. CONCLUSIONS: Performance of push enteroscopy along with esophagogastroduodenoscopy increases the diagnostic yield from 41% to 67% when evaluating the upper gastrointestinal tract of asymptomatic patients with iron-deficiency anemia and, because of a lower cost, should be the preferred initial diagnostic test.

Identification and functional characterization of a second chain of the interleukin-10 receptor complex.

Interleukin-10 (IL-10) is a pleiotropic cytokine which signals through a specific cell surface receptor complex. Only one chain, that for ligand binding (IL-10Ralpha or IL-10R1), was identified previously. We report here that, although human IL-10 binds to the human IL-10R1 chain expressed in hamster cells, it does not induce signal transduction. However, the co-expression of CRFB4, a transmembrane protein of previously unknown function belonging to the class II cytokine receptor family, together with the IL-10R1 chain renders hamster cells sensitive to IL-10. The IL-10:CRFB4 complex was detected by cross-linking to labeled IL-10. In addition, the IL-10R1 chain was able to be co-immunoprecipitated with anti-CRF antibody when peripheral blood mononuclear cells were treated with IL-10. These results demonstrate that the CRFB4 chain is part of the IL-10 receptor signaling complex. Thus, the CRFB4 chain, which we designate as the IL-10R2 or IL-10Rbeta chain, serves as an accessory chain essential for the active IL-10 receptor complex and to initiate IL-10-induced signal transduction events.

What predicts gastroenterologists' and surgeons' diagnosis and management of common bile duct stones?

BACKGROUND: Because the literature suggests numerous indicators of common bile duct stones, we undertook a systematic assessment of physicians' judgments of the clinical utility of eight indicators: patient age, history of jaundice, history of pancreatitis, levels of serum alanine aminotransferase, alkaline phosphatase, amylase, and total bilirubin, and common bile duct diameter on ultrasonography. METHODS: Random samples of 1500 gastroenterologists and 1500 surgeons were sent a survey asking them to indicate the importance of each potential indicator of common bile duct stones, the likelihood of common bile duct stones for each of nine clinical vignettes, and whether they would order a preoperative ERCP. An abbreviated survey was sent to nonrespondents. RESULTS: Although there was substantial variation in the importances assigned to each indicator, the most important indicators were serum total bilirubin and diameter of common bile duct on ultrasound. The best predictors of the decision to order an ERCP were perceived likelihood of stones and specialty. The average threshold for ordering an ERCP was 37%. Respondents did not differ from nonrespondents in the perceived importance of the eight indicators. CONCLUSIONS: The substantial variation among gastroenterologists and surgeons regarding the optimal approach to common bile duct stones has clinical implications. Patients will receive varying recommendations for care, depending on whom they see.

Localized thrombotic purpura: a rare complication of chickenpox.

We report three cases of localized thrombotic purpura that appeared during the convalescence phase of common chickenpox. This rare complication is characterized by localized symmetric ecchymotic purpura often affecting the lower limbs and often accompanied with signs of disseminated intravascular coagulation. In two cases we found transient protein S deficiency.

Other kinases can substitute for Jak2 in signal transduction by interferon-gamma.

Each cytokine which utilizes the Jak-Stat signal transduction pathway activates a distinct combination of members of the Jak and Stat families. Thus, either the Jaks, the Stats, or both could contribute to the specificity of ligand action. With the use of chimeric receptors involving the interferon gamma receptor (IFN-gammaR) complex as a model system, we demonstrate that Jak2 activation is not an absolute requirement for IFN-gamma signaling. Other members of the Jak family can functionally substitute for Jak2. IFN-gamma can signal through the activation of Jak family members other than Jak2 as measured by Statlalpha homodimerization and major histocompatibility complex class I antigen expression. This indicates that Jaks are interchangeable and indiscriminative in the Jak-Stat signal transduction pathway. The necessity for the activation of one particular kinase during signaling can be overcome by recruiting another kinase to the receptor complex. The results may suggest that the Jaks do not contribute to the specificity of signal transduction in the Jak-Stat pathway to the same degree as Stats.

Endoscopic ultrasonography.

Optimal treatment of gastric carcinoma requires accurate staging as there are marked differences in the prognosis of early and advanced gastric cancer which influence the decision for surgical resection versus nonsurgical palliation. Endoscopic ultrasonography (EUS), by virtue of its considerable accuracy, has become the method of choice for regional staging of gastric cancer. EUS is unique in its ability to image the gastric wall as a 5-layer structure that correlates with actual histological layers. Thus, tumor depth can be imaged very precisely. Peritumor inflammation is the most common cause for overstaging by EUS; difficulty in determining tumor involvement of, but not through, the subserosa is another important reason for inaccurate staging. EUS is able also to detect small lymph nodes in the perigastric region. Although assessment of malignancy in nodes can be difficult, ultrasound-guided fine needle aspiration cytology appears to be an accurate method to determine lymph node status. Surgery remains the standard treatment for gastric cancer, but new methods of endoscopic resection combined with high-frequency ultrasound may hold promise for future treatment of early gastric cancer. In addition to current radial and sector scanning instruments, recently introduced high-frequency ultrasound probes enhance the diagnostic possibilities of this technology.