Endoscopic treatment for early duodenal papillary carcinoma: long-term outcomes

BACKGROUND AND AIM

This study aims to determine whether endoscopic papillectomy (EP) is a safe and effective treatment for early duodenal papillary carcinoma with long-term follow-up.

METHODS

From June 2012 to September 2022, 48 patients with early duodenal papilloma carcinoma who received endoscopic treatment were included. The histological types, percentage of complete resections, postoperative residuals, adverse events, and recurrences were evaluated.

RESULTS

EP was successful in all patients; 46 were lumped, and two were fragmented, with a 95.8% intact removal rate (46/48). The preoperative biopsy pathological positive rate was 70.8% (34/48). The incidence of early postoperative adverse events (within 1 month after EP) were 16.7% (8/48), including four cases of acute pancreatitis, three cases of delayed bleeding, and one case of acute cholangitis. In addition, 4.2% (2/48) of the late adverse events were bile duct stenosis. After 6 months, the postoperative residual rate was 0%. The median time to recurrence was 17.5 months, and the postoperative recurrence rate was 16.7% (8/48) in patients treated with radiofrequency ablation. The median progression-free survival was 18.6 months (95% CI, 12.1-25.1), and the median overall survival was 121.5 months (95% CI, 105.6-120.9).

CONCLUSIONS

EP is a safe and efficient alternative therapy for early duodenal papillary carcinoma. Endoscopic follow-up and treatment are essential because of the potential for recurrence.

The Impact of Noninvasive Ventilator Assisted Ventilation Nursing Combined with Mechanical Vibration on the Level of Heart Failure Indexes in ICU Patients with Acute Heart Failure

The acute attack of acute heart failure or the continuous deterioration of cardiac function leads to a series of changes such as reduced cardiac contractility, increased cardiac load, and a sudden drop of acute cardiac output, which eventually cause pulmonary circulation congestion and acute dyspnea due to acute pulmonary congestion. To observe the impact of noninvasive ventilator-assisted ventilation nursing combined with mechanical vibration on the level of heart failure indexes in intensive care unit (ICU) patients with acute heart failure, 120 patients with acute heart failure who were treated in the ICU ward of our hospital from September 2018 to March 2021 were selected, and the qualified subjects were divided into two groups according to the 1 : 1 principle by a simple random method. 120 patients were given conventional symptomatic treatment and noninvasive ventilator-assisted ventilation. The control group received conventional nursing intervention, and the observation group was given noninvasive ventilator-assisted ventilation nursing and mechanical vibration intervention. The respiratory system indexes, heart rate, blood pressure, central venous pressure, N-terminal B-type natriuretic peptide precursor (NT-proBNP), cardiac troponin T (cTnT), and cardiac function indexes of the two groups of patients are recorded, and the prognosis of the two groups is compared. After intervention, the partial pressure of oxygen (PaO2) and blood oxygen saturation (SpO2) in the two groups were higher than those before intervention, while the partial pressure of carbon dioxide (PaCO2), respiration (RR), heart rate, blood pressure, and central venous pressure were lower than those before intervention (P < 0.05). Compared with the control group, PaO2, SpO2, systolic blood pressure, diastolic blood pressure, and central venous pressure of the observation group after intervention were significantly higher, while PaCO2, RR, and heart rate were significantly lower (P < 0.05). Compared with the control group, the LVEF of the observation group after intervention was significantly higher, while NT-proBNP, cTnT, LVESD, and LVEDD were markedly lower (P < 0.05). The ventilation time and ICU hospitalization time in the observation group were shorter than those in the control group, and the pulmonary infection rate was lower than in the control group. The remission time of infection in patients with pulmonary infection was shorter than that in the control group. When comparing the 28d mortality rate with the control group, the difference was not statistically significant (P > 0.05). Noninvasive ventilator-assisted ventilation nursing combined with mechanical vibration can improve hypoxemia symptoms and heart function, stabilize hemodynamics, shorten the course of disease and reduce the occurrence of lung infections for those patients with acute heart failure in the ICU.

Biliary Microbial Structure of Gallstone Patients With a History of Endoscopic Sphincterotomy Surgery

The biliary microbiota is related to the pathogenesis of human bile duct stones. However, the extent to which a history of invasive endoscopic sphincterotomy (EST) affects the biliary bacterial community remains largely unknown. We collected bile samples from the common bile duct of 100 choledocholithiasis patients. We performed 16S rRNA sequencing to investigate and compare the biliary microbial community. The patients without antibiotic treatment (AT) were grouped into three clusters based on their biliary microbial compositions. The patients with a history of EST were significantly enriched in one cluster mainly consisting of gastrointestinal bacteria compared with the other two clusters consisting of oral and environmental bacteria. The β-diversities of patients with and without EST were also significantly different, whereas the α-diversities were comparable. The only significantly enriched bacterial genus associated with a history of EST was Pyramidobacter, while eight other genera were significantly decreased. For patients with AT, seven of these genera maintained their association with EST, including Pyramidobacter. However, after AT, the difference in β-diversities was diminished. EST induced a marked shift in the biliary microbial composition. A cluster of biliary bacteria was associated with a history of EST, and Pyramidobacter was specific to EST.

Successful Therapeutic ERCP in a 99-Day-Old Child With Common Bile Duct Stones: A Case Report and Discussions on the Particularities of the ERCP in Children

Backgroud: At present, therapeutic endoscopic retrograde cholangiopancreatography (ERCP) has gradually been used in the diagnosis and treatment of biliary and pancreatic diseases in children, but reports on and the application of ERCP in children, especially in infants, are still highly limited. Case Presentation: This case report describes a 99-day-old infant with choledocholithiasis who successfully underwent ERCP to relieve an obstruction. The infant developed obstructive jaundice during chemotherapy for a malignant tumor, and a routine blood examination showed signs of infection. Liver damage also occurred. B-ultrasound suggested stones in the lower segment of the common bile duct (CBD). After sufficient communication and preparation, biliary drainage was successfully carried out in the infant using adult duodenoscope (JF240) and related instruments with cooperation from the Department of Anesthesiology. Conclusions: This paper preliminarily introduces our experience with adult duodenoscope in children, providing a good example for hospitals without a special duodenoscope for children to carry out pediatric ERCP. Clinicians should pay close attention to the need of careful use of ERCP in infants.

Rectal Indomethacin and Spraying of Duodenal Papilla With Epinephrine Increases Risk of Pancreatitis Following Endoscopic Retrograde Cholangiopancreatography

BACKGROUND & AIMS

Rectal indomethacin and spraying of the duodenal papilla with epinephrine might reduce the incidence of pancreatitis after endoscopic retrograde cholangiopancreatography (ERCP). We performed a randomized trial to compare the effects of the combination of indomethacin and epinephrine (IE) vs indomethacin plus saline (IS) in prophylaxis of post-ERCP pancreatitis (PEP).

METHODS

We performed a double-blind trial at 10 centers in China, from February 2017 to October 2017, of 1158 patients with native papilla undergoing ERCP. The patients were assigned randomly to groups given IE (n = 576) or IS (n = 582). All patients received a single dose of rectal indomethacin within 30 minutes before ERCP; 20 mL of dilute epinephrine (IE group) or saline (IS group) then was sprayed on the duodenal papilla at the end of ERCP. The primary outcome was the incidence of overall PEP. Data were analyzed on an intention-to-treat principle.

RESULTS

The study was terminated at the interim analysis for safety concerns and futility. The groups had similar baseline characteristics. PEP developed in 49 patients in the IE group (8.5%) and in 31 patients in the IS group (5.3%) (relative risk, 1.60, 95% CI, 1.03-2.47; P = .033). There were no significant differences between groups in proportions of patients with postsphincterotomy bleeding (2.1% in the IE group and 1.5% in the IS group) and biliary infection (1.2% in the IE group and 2.2% in the IS group).

CONCLUSIONS

In a randomized trial, we found the combination of rectal indomethacin with papillary epinephrine spraying increased the risk of PEP compared with indomethacin alone. Spray epinephrine should not be used with rectal indomethacin for prevention of post-ERCP pancreatitis. ClincialTrials.gov no: NCT03057769.

Efficacy and safety of endoscopic radiofrequency ablation for unresectable extrahepatic cholangiocarcinoma: a randomized trial

BACKGROUND

Endoscopic placement of biliary stents to relieve jaundice is the main palliative treatment for unresectable extrahepatic cholangiocarcinoma. Endoscopic biliary radiofrequency ablation (RFA) has been reported to prolong stent patency, which may be beneficial in improving patient survival. However, available evidence is still insufficient, as most reported studies are retrospective case series. The aim of this study was to explore the clinical effect and safety of RFA in patients with unresectable extrahepatic cholangiocarcinoma.

METHODS

65 patients with unresectable extrahepatic cholangiocarcinoma, except Bismuth type III and IV hilar cholangiocarcinoma, were enrolled and randomly underwent either RFA combined with biliary stenting (RFA + stent group; n = 32) or biliary stent only (stent-only group; n = 33). Overall survival time, stent patency period, and postoperative adverse events were recorded.

RESULTS

In the 21-month follow-up period, the overall mean survival time was significantly longer in the RFA + stent group than in the stent-only group (13.2 ± 0.6 vs. 8.3 ± 0.5 months; P < 0.001). The mean stent patency period of the RFA + stent group was also significantly longer than that of the stent-only group (6.8 vs. 3.4 months; P = 0.02). There was no significant difference in the incidence of postoperative adverse events between the two groups (6.3 % [2/32] vs. 9.1 % [3/33]; P = 0.67).

CONCLUSION

Endoscopic RFA combined with stenting can significantly prolong survival and the stent patency period without increasing the incidence of adverse events in patients with extrahepatic cholangiocarcinoma patient, except Bismuth type III and IV hilar cholangiocarcinoma. This approach can be considered as a safe and effective palliative treatment for these patients.

Detection of hand-foot-mouth disease and its spatial-temporal Epidemiological characteristics with GIS platform

The aim of this study is to investigate the main category of hand-foot-mouth (HFM) virus and analyze the distribution characteristics and susceptible population of HFM disease in China. Infants who have had HFM disease for less than 7 days were selected from the First Affiliated Hospital of Guangxi Medical University, Guangxi, China. Various specimens were collected from the infants, and EV71 and CA16 nucleic acid detections were performed using fluorescence quantitative assay. The positive results of the specimens were compared to determine the components of the pathogen. Moreover, the data of the target cases were analyzed based on Geographic Information System (GIS) to obtain the spatial-temporal epidemiological features of HFM disease in China. The detection rate of HFM virus in the throat swab, feces, bleb fluid and cerebrospinal fluid were 75%, 81.13%, 85.71% and 25%, respectively, indicating that the detection rate of virus in the bleb fluid was the highest. When the detection was based on more than one specimen, it was found that the positive rate was higher compared to detection based on a single specimen. The positive detection rate of EV71 in the target specimens was significantly higher than that of CA16 and mixed infection. Moreover, CA16 infection was usually accompanied by EV71 infection. As to spatial-temporal distribution, hand-foot-month disease broke out in the South of China in April, then spread to the north, and diminished in July. There was a notable difference in the number of cases between different provinces. EV71 and CA16 are the main viruses inducing HFM disease, especially EV71. Fluorescence quantitative polymerase chain reaction with high sensitivity can be used to detect the copy number of viruses, which is applicable to the early diagnosis of HFM disease. The incidence of HFM disease is notably different according to the influence of time, geographical space, gender and the living conditions of the children. Early diagnosis and treatment based on scientific methods are needed to reduce the incidence of severe diseases and avoid death.

Treatment of unresectable extrahepatic cholangiocarcinoma using hematoporphyrin photodynamic therapy: A prospective study

BACKGROUND

The available evidence of Photodynamic therapy (PDT) combined with stent placement treatment for unresectable extrahepatic cholangiocarcinoma (EHCC) is still insufficient. It also remains unclear whether PDT influences systemic inflammatory response.

AIM

To explore the clinical efficacy and safety of the combination treatment and the systemic inflammatory response in patients with EHCC.

METHODS

Patients with unresectable EHCC underwent either the combined treatment using Hematoporphyrin PDT and stent placement (PDT+stent group, n=12) or stent-only (stent group, n=27). The primary end-point was overall survival. Tumor necrosis factor (TNF)-α and interleukin (IL)-6 levels were measured. Quality of life was assessed using the Karnofsky performance scale (KPS) every 3 months.

RESULTS

Average survival time (13.8 vs. 9.6 months), and 6-month (91.7% vs. 74.1%), and 1-year (58.3% vs. 3.7%) survival rates of PDT+stent group were significantly increased compared with the stent group. KPS scores in the PDT+stent group were significantly improved. TNF-α and IL-6 levels were significantly increased in the PDT+stent group.

CONCLUSION

Hematoporphyrin-PDT combined with stent placement is an effective and safe treatment for EHCC. The treatment might promote systemic inflammatory response.

Development and characterization of potent and specific peptide inhibitors of p60c-src protein tyrosine kinase using pseudosubstrate-based inhibitor design approach

The cytoplasmic protein p60c-src, an ubiquitous non-receptor protein tyrosine kinase (PTK) is a potential anticancer target as it is over-expressed and/or constitutively active in several cancer types. In addition, the phenotype of c-src knock-out mice is consistent with osteopetrosis, which suggests that inhibitors against this enzyme may also be therapeutic for osteoporosis. Using a known peptide substrate for c-src, MIYKYYF, as a template, we have developed a series of pseudosubstrate-based peptide inhibitors. Structure-activity relationship studies have been performed on one of these inhibitors, CIYKYYF. In a kinase assay using YIYGSFK as the substrate, CIYKYY has been demonstrated to inhibit p60c-src, with an IC50 of 0.6 microm. Further truncation has led to the determination that even the smaller peptide, CIYK, is a moderately potent inhibitor with IC50 of 15 microm. Some improvement in inhibitory potency (IC50 = 11.8 microm) has been observed with the replacement of Tyr3 in CIYK with beta-phenylalanine (beta-Phe). The tetrapeptide CI(beta-Phe)K will be used as a lead compound for future development of peptidomimetics and small molecule inhibitors that have the capacity to penetrate the plasma membrane of intact cells.

A comparison of the effect of three sedatives on esophageal sphincters in cats

BACKGROUND/AIMS

Children 5 years old and younger often require sedation for esophageal motility studies (EMS). At our institution, an intramuscular cocktail of meperidine, promethazine and chlorpromazine (MPC) has been used as the standard sedative for young children undergoing EMS. Administering the intramuscular sedative may, however, be more traumatic to the child than the procedure. Moreover, its effect on esophageal motility is not known and prolonged sedation is common. The aim of this study was to determine the effects of MPC and two orally-administered sedatives on esophageal sphincter function, using the cat model, with a goal to identify a potentially suitable orally-administered sedative for use in young children requiring sedation for EMS.

METHODS

We measured upper (UESP) and lower (LESP) esophageal sphincter pressures in 25 cats initially without sedation, and then following sedation with midazolam, chloral hydrate and MPC. The results were compared.

RESULTS

All three sedatives significantly decreased LESP compared to the control (p<0.05). Midazolam decreased LESP the most; however, the difference from the other sedatives did not reach statistical significance. All three sedatives decreased UESP, compared to control, but the differences were not statistically significant. Of the two oral sedatives, chloral hydrate had the least effect on the esophageal sphincters although its effect was not statistically different from that of midazolam.

CONCLUSIONS

Ethically appropriate studies are needed to determine which oral sedative would be most beneficial for use in sedating children undergoing esophageal motility studies. Until studies can be done, the choice between chloral hydrate and midazolam should be based on the experience and comfort of the attending physician with regard to the potential side effects of the medications.

Comparison of five PCR methods for detection of Helicobacter pylori DNA in gastric tissues

Five different PCR methods for the detection of Helicobacter pylori were evaluated. The results of this study indicate that of the five PCR methods examined, the ureC (glmM) gene PCR is the most sensitive and specific for the detection of H. pylori in gastric biopsy specimens.

A Lewis(y) epitope mimicking peptide induces anti-Lewis(y) immune responses in rabbits and mice

Lewis(y) carbohydrate antigens are abundant on the surface of many carcinomas. Mab B3 directed against this carbohydrate antigen has been used to make an immunotoxin that is very cytotoxic to cancer cells expressing the Lewis(y) antigen. Mab B3 was also used to screen a phage-displayed peptide library and identified a peptide mimicking the Lewis(y) epitope. In this report, we demonstrate that the Lewis(y) epitope-mimicking peptide induces anti-Lewis(y)immune responses in both rabbits and mice. In addition, Lewis(y) antigens induce anti-peptide immune responses. These results indicate that carbohydrate-mimicking peptides provide a novel strategy to elicit immune responses for tumor-associated carbohydrates.

Prevalence of immunoglobulin G to Helicobacter pylori among endoscopy nurses/technicians

The purpose of this study was to compare the prevalence of Helicobacter pylori (HP) seropositivity among gastroenterology nurses and technicians with that of the general population. Nurses attending the 1996 Indiana Society of Gastroenterology Nurses and Associates Spring and Fall Education Courses were asked to complete a checklist regarding employment, current symptoms, and use of universal precautions, and to have 3 ml blood drawn. These 138 blood specimens as well as 112 serum samples from generally age- and sex-matched blood donors (representing the general population) underwent qualitative HP antibody testing. Results showed that the prevalence of seropositivity for immunoglobulin G (IgG) antibody for HP among the gastroenterology nurses and technicians was 19 of 138 (13.8%), which was less than that of the blood donor control group, whose seropositivity was 20 of 112 (17.9%). However, this difference failed to reach statistical significance. Seropositivity tended to increase with age, but there was no association between clinical symptomatology and seropositivity. Likewise, there was no difference in seropositivity between nurses assisting with endoscopic procedures for more than 10 years and those assisting for less than 10 years. Although the differences were not significant, these findings refute those of an earlier study in which the researchers found 122 gastroendoscopists and endoscopy nurses significantly more likely to be positive for HP antibodies. Therefore, the findings reported here provide important information.

Discovery of a novel series of potent and selective substrate-based inhibitors of p60c-src protein tyrosine kinase: conformational and topographical constraints in peptide design

On the basis of the efficient substrate for p60c-src protein tyrosine kinase (PTK) YIYGSFK-NH2 (1) (Km = 55 microM) obtained by combinatorial methods, we have designed and synthesized a series of conformationally and topographically constrained substrate-based peptide inhibitors of this enzyme, which showed IC50 values in the low-micromolar range (1-3 microM). A "rotamer scan" was performed by introducing the four stereoisomers of beta-Me(2')Nal in the postulated interaction site of the peptide inhibitor 23(IC50 = 1.6 microM). This substitution led to selective and potent inhibitors of p60c-src PTK; however, no substantial difference in potency was observed among them. This and the results of the "stereochemical scan" performed at residues 2 and 7 of 3 (peptides 19-21), which form the disulfide bond, may suggest that the enzyme active site does not have rigid topographic requirements and thus is able to achieve important conformational changes to bind the ligand as long as the pharmacophore pattern in the inhibitor is conserved. Two new potent iodo-containing nonphosphorylatable tyrosine analogues were also incorporated into our lead inhibitory sequence 23, producing the most potent inhibitors for p60c-src PTK identified thus far in our studies. Compounds 29 and 30 exhibit IC50 values of 0.13 and 0.54 microM, respectively. Peptide 29 is 420-fold more potent than the parent peptide 1. Selectivity studies of peptides 23-30 toward p60c-src, Lyn, and Lck PTK showed in general high Lyn/Src and moderate Lck/Src selectivity ratios. We found that the chi1 space constraints of the specialized amino acids, introduced at position 3 of the peptide lead 23, were not as important as the configuration of the Calpha of that residue to recognize the subtle chemical environment surrounding the active site of Src and Lck PTK, as reflected on the obtained Lck/Src selectivity ratios.

Application of "one-bead one-compound" combinatorial library methods in signal transduction research

Using a "split-synthesis" solid phase synthetic approach, bead libraries can be generated such that each bead displays only one chemical entity. This "one-bead one-compound" combinatorial library can then be assayed for specific biological properties using either a solid-phase on-bead binding or functional assay, or a releasable solution phase assay. Positive compound-beads can then be isolated for structure determination. Various assay systems to screen such a "one-bead one-compound" library are described. We have used this combinatorial library method to discover peptides that bind to the cell surface immunoglobulins of murine lymphoma cells. Such peptides, when presented in an oligomeric form to a lymphoma cell are able to induce signal transduction. Additionally, we have also applied the "one-bead one-compound" combinatory library approach to elucidate peptide substrate motifs for protein tyrosine kinases. Multiple distinct peptide motifs were identified for p60(c-src) protein tyrosine kinase. Using the identified peptide substrates as templates, potent and highly specific pseudosubstrate-based peptide inhibitors were developed.

Idiotype specific peptides bind to the surface immunoglobulins of two murine B-cell lymphoma lines, inducing signal transduction

Using a random combinatorial synthetic peptide library method based on a one-bead one-peptide concept for ligand identification (Lam et. al, Nature 1991, 354, 82-84.), idiotype specific peptides were retrieved and optimized for interaction with the cell surface immunoglobulins [IgM(kappa)] of two murine B lymphoma cell lines. Several of the identified peptides were characterized with respect to cell binding and signal transduction. These peptides were able to bind specifically to the surface immunoglobulins of these lymphoma cells. In addition to binding, when synthesized in tetrameric or multimeric forms, the peptides were able to trigger signal transduction resulting in an increase in protein tyrosine phosphorylation. Since D-amino acid peptide libraries were used in some of our efforts to identify binding ligands, several of the idiotype-specific peptides are composed of all D-amino acids (e.g. wGeyvmvnG). These findings may have important therapeutic implications for targeted-therapy of B-cell lymphoma as these D-amino acid ligands are more resistant to proteolysis resulting in a prolonged pharmacokinetic disposition in vivo.

Potent pseudosubstrate-based peptide inhibitors for p60(c-src) protein tyrosine kinase

We recently reported the identification of GIYWHHY as an efficient and specific substrate for p60(c-src) protein tyrosine kinase (PTK) by screening a secondary random peptide library (Q. Lou et al., Bioorg. Med. Chem., 4: 677-682, 1996). Based on the primary structure of GIYWHHY, we designed and synthesized several pseudosubstrate-based peptide inhibitors. Some of these peptide inhibitors are highly potent and specific with IC50 in the low micromolar range. Because both YIYGSFK and GIYWHHY are efficient and specific substrates for p60(c-src) PTK, chimeric branched peptides based on these two sequences were synthesized. These branched peptides inhibit p60(c-src) PTK with high potency, indicating that the enzyme-active site of p60(c-src) PTK can accommodate more than a linear motif. This may explain why seemingly several peptides with very different linear structures can all be phosphorylated by this enzyme.

Rapid and effective method for preparation of fecal specimens for PCR assays

We have developed a novel method for the preparation of fecal specimens for PCR assays. Approximately 100 mg of solid stool or 200 microliters of liquid fecal sample was thoroughly suspended in 1 ml of water. Fecal debris was removed by low-speed centrifugation (2,800 x g for 2 min). The supernatant was then boiled for 10 min in a water bath and further clarified by high-speed centrifugation (12,000 x g for 5 min). Fifty microliters of the clarified supernatant was then purified by Sepharose CL-6B spin column chromatography, and a portion of the purified supernatant was used for PCR. By this method, stools containing enterotoxigenic Escherichia coli H10407 were amplified by colonization factor antigen I fimbrial gene PCR, with a sensitivity of 100 organisms per reaction. The method was also effective for processing stool specimens for Clostridium difficile toxin A and B gene PCRs. This method is rapid, effective, and simple to perform and will improve the applications of PCR to stool specimens for diagnostic purposes.

Evaluation of 16S rRNA gene PCR with primers Hp1 and Hp2 for detection of Helicobacter pylori

The PCR primer set Hp1-Hp2, which amplifies a 109-bp fragment of the 16S rRNA gene of Helicobacter pylori, has been widely used for the detection of H. pylori in clinical specimens. We have examined 34 stool samples and 50 human tissue samples from H. pylori-infected and uninfected patients, five human leukocyte samples, and one human cell line by this PCR method. All of these specimens produced a 109-bp PCR product. When Escherichia coli DNA was used as the template, several nonspecific bands, but not the 109-bp band, were observed. No PCR products were generated when DNA samples from five different fungi were used as templates. These results indicate that this 109-bp PCR product was amplified from the human genome. The 109-bp PCR product generated from various clinical specimens also hybridized with the probe pHp, corresponding to a region internal to the PCR product of Hp1-Hp2. We conclude that the 16S rRNA gene PCR with the primer set Hp1-Hp2 is not specific and cannot be used to detect H. pylori in clinical specimens.

Identification of GIYWHHY as a novel peptide substrate for human p60c-src protein tyrosine kinase

We have recently determined that -Ile-Tyr- were the two critical residues as a peptide substrate for p60c-src protein tyrosine kinase (Lou, Q. et al., Lett. Peptide Sci., 1995, 2, 289). Here, we report on the design and synthesis of a secondary 'one-bead, one-compound' combinatorial peptide library based on this dipeptide motif (XIYXXXX, where X = all 19 eukaryotic amino acids except for cysteine). This secondary library was screened for its ability to be phosphorylated by p60c-src PTK using [gamma 32P]ATP as a tracer. Five of the strongest [32P]-labeled peptide-beads were identified and microsequenced: GIYWHHY, KIYDDYE, EIYEENG, EIYEEYE, and YIYEEED. A solid-phase phosphorylation assay was used to evaluate the structure-activity relationship of GIYWHHY. It was determined that Ile2, Tyr3, His5, and His6 were crucial for its activity as a substrate.

Helicobacter pylori infection in recurrent abdominal pain in childhood: comparison of diagnostic tests and therapy

OBJECTIVE

To determine the role of Helicobacter pylori infection in children with recurrent abdominal pain and the usefulness of serologic tests in screening H pylori infection and monitoring treatment of H pylori-associated gastritis.

METHODS

During a 3 year period, we investigated the presence of serum immunoglobulin G (IgG) antibody to H pylori in 456 children using the high-molecular-weight cell-associated protein H pylori enzyme immunoassay kit. Among the 456 children studied, 218 (age range, 3 to 18 years; mean age, 9.5 years) had symptoms of recurrent abdominal pain (RAP syndrome) with or without vomiting, and the remaining 238 (age range, 3 to 18 years; mean age, 9.8 years) had no RAP (non-RAP syndrome). We performed upper gastrointestinal endoscopy on 111 consecutive children of the 218 with RAP syndrome and obtained mucosal biopsies for culture, histologic analysis, CLO test (Delta West, Perth, Australia), and H pylori detection by polymerase chain reaction.

RESULTS

Thirty-eight (17.4%) of 218 children in the RAP group and 25 (10.5%) of 238 children in the non-RAP group were seropositive for H pylori. Of the 111 children endoscoped, 95 were found to be negative, and 12 were positive by all five assays. Specimens from 2 children were negative by culture and the CLO test but positive by the other three assays. Specimens from 1 child were negative by histologic analysis but positive by all other tests. The remaining child was positive for anti-H pylori IgG but negative by all of the other four assays. Upper gastrointestinal endoscopy detected 14 children with peptic ulcer disease (9 duodenal ulcer and 5 gastric ulcer) and 12 with antral nodular gastritis. Only 4 of the 14 diagnosed with peptic ulcer were H pylori positive by all five assays, whereas all 12 children with antral nodular gastritis were H pylori positive. Nine of the 12 H pylori-positive children were treated with a combination of bismuth subsalicylate, amoxicillin, and metronidazole for 2 weeks. Sera obtained at 2, 4, and 6 months after treatment from all 9 children showed a decrease in anti-H pylori IgG titer. Three H pylori-infected children who did not receive any treatment served as control children, and their IgG levels remained elevated or increased over time.

CONCLUSION

The results from our study indicate that screening for the serum IgG antibody to H pylori is a practical method for diagnosing H pylori infection in children, and that serial measurements of the H pylori IgG antibody are useful for monitoring treatment of H pylori because of its high sensitivity and ease of performance. Only 4 of the 14 children diagnosed with peptic ulcer disease were confirmed to be infected with H pylori, whereas all 12 children with antral nodular gastritis were found to be infected by H pylori. These observations suggest that H pylori infection is more frequently associated with gastritis than with peptic ulcer disease in children, and that H pylori gastritis is a cause of RAP syndrome in children.

Identification and characterization of a novel synthetic peptide substrate specific for Src-family protein tyrosine kinases

Using a random combinatorial peptide library method [Wu, J., Ma, Q. N. & Lam, K. S. (1994) Biochemistry 33, 14825-14833] a novel peptide, YIYGSFK, was identified as a substrate for p60c-src protein tyrosine kinase. Mass spectrometric analysis showed that tyrosine-3 from the N-terminus was the phosphorylation site. Kinetic studies showed that the Km of YIYGSFK for p60c-src was 55 microM, about 6.4-fold lower than a peptide derived from p34cdc2 [cdc2(6-20), KVEKIGEGTYGVVYK], which had been reported to be a specific and efficient substrate for the Src-family protein tyrosine kinases. Comparison of the specificity of YIYGSFK and cdc2(6-20) as a substrate for various Src-family and non-Src-family protein tyrosine kinases suggests that YIYGSFK is a much more specific and efficient substrate for the Src-family protein tyrosine kinases.

Operation of a Ti:sapphire laser pumped by a 499-nm green laser

We report, for the first time, to our knowledge, the operation of a tunable Ti:sapphire laser pumped by a third-order Raman XeCl-H(2) laser system at 499 nm with a 60-ns pulse duration. The slope efficiency is 59% for this laser, producing pulses of 20-ns duration. The highest conversion-energy efficiency obtained is 41%, with an output energy of 1.2 mJ. The tuning range for a single set of cavity mirrors is 680-834 nm and is limited mainly by the mirror reflectivity. This study shows that a combined laser system based on a XeCl excimer laser can offer wavelength diversity.