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Paul Harris

Publications and source records attributed to Paul Harris.

13 recordsLinked to original sources
PubMed2006

Non-invasive diagnosis of gastric mucosal atrophy in an asymptomatic population with high prevalence of gastric cancer.

AIM: To validate a non-invasive method to detect gastric mucosal atrophy in a Chilean population with high prevalence of gastric cancer and a poor survival rate. METHODS: We first determined the optimal cut-off level of serum pepsinogen (PG)-1, PG-1/PG-2 ratio and 17-gastrin in 31 voluntary symptomatic patients (mean age: 66.1 years), of them 61% had histologically confirmed gastric atrophy. Then, in a population-based sample of 536 healthy individuals (209 residents in counties with higher relative risk and 327 residents in counties with lower relative risk for gastric cancer), we measured serum anti-H pylori antibodies, PG and 17-gastrin and estimated their risk of gastric cancer. RESULTS: We found that serum PG-1 < 61.5 microg/L, PG-1/PG-2 ratio < 2.2 and 17-gastrin > 13.3 pmol/L had a high specificity (91%-100%) and a fair sensitivity (56%-78%) to detect corpus-predominant atrophy. Based on low serum PG-1 and PG-1/PG-2 ratio together as diagnostic criteria, 12.5% of the asymptomatic subjects had corpus-predominant atrophy (0% of those under 25 years and 20.2% over 65 years old). The frequency of gastric atrophy was similar (12% vs 13%) but H pylori infection rate was slightly higher (77% vs 71%) in the high-risk compared to the low-risk counties. Based on their estimated gastric cancer risk, individuals were classified as: low-risk group (no H pylori infection and no atrophy; n = 115; 21.4%); moderate-risk group (H pylori infection but no atrophy; n = 354, 66.0%); and high-risk group (gastric atrophy, with or without H pylori infection; n = 67, 12.5%). The high-risk group was significantly older (mean age: 61.9+/-13.3 years), more frequently men and less educated as compared with the low-risk group. CONCLUSION: We propose to concentrate on an upper gastrointestinal endoscopy for detection of early gastric cancer in the high-risk group. This intervention model could improve the poor prognosis of gastric cancer in Chile.

Adult↗
PubMed2006

Polysomnographic findings in 320 infants evaluated for apneic events.

Apnea is a common problem that causes significant parental anxiety. The aim of this study was to describe polysomnographic findings in infants who were referred over a 4-year period for an apnea and/or cyanotic event. Our hypothesis was that most infants with apnea or cyanosis events will have normal polysomnography (PSG). In total, 320 patients younger than 2 years old were recruited sequentially and prospectively. Patients underwent a day or overnight PSG by computerized polysomnograph; 78% of studies were performed with pH probe in situ. Subjects' ages ranged from 10 days to 21 months (55% male and 84% full-term babies); 55% and 74% were younger than 3 and 6 months, respectively. The average total sleep time was 473.4 min (SD, 52.3), with mean sleep efficiency of 83.5%. The distribution of sleep stages was 56.5% active, 38.5%, quiet and 5.1% indeterminate sleep. Sixty-nine percent (n = 220) of PSG studies were done overnight. There were significant differences in average sleep efficiency (78.1% vs. 83.3%) and REM sleep time (63.6% vs. 59.1%) between PSGs done during the day and overnight (P < 0.05). In total, 34 patients with apneas were studied. The median apnea index for the whole study population was 1.01 (range, 0.1-9.1). In conclusion, our study showed a high prevalence of normal polysomnographic findings in infants referred because of apnea and/or cyanotic events. New clinical prospective studies should be conducted to evaluate whether there is a correlation between PSG findings and outcome at follow-up of infants with a history of apnea and cyanosis.

Age Distribution↗
PubMed2005

Hemolytic uremic syndrome associated with Entamoeba histolytica intestinal infection.

Amebiasis secondary to Entamoeba histolytica (E. histolytica) continues to be a major source of morbidity and mortality worldwide, mainly in developing countries. An association between amebic dysentery and hemolytic uremic syndrome (HUS) has been mentioned, but a cause-and-effect relationship has never been confirmed. We report the case of an 11-year-old healthy white female who developed severe bloody diarrhea after drinking contaminated unboiled water, developing classic HUS and requiring acute intermittent hemodialysis. The etiological study confirmed numerous cysts and hematophagous trophozoites of E. histolytica on stool smear, but without evidence of other pathogens. This report contributes to the concept that classic post-diarrheal HUS, usually related to colitis secondary to enterohemorragic Shiga-toxin producing Escherichia coli (E.coli) strains, may be associated with other pathogens, including E. histolytica. Additional information regarding mechanisms of virulence of E. histolytica and host immunological reaction is needed to clarify the temporal association of these two disorders (HUS and amebiasis).

Child↗
PubMed2005

Hyperadrenergic postural tachycardia syndrome in mast cell activation disorders.

Postural tachycardia syndrome (POTS) is a disabling condition that commonly affects otherwise normal young females. Because these patients can present with a flushing disorder, we hypothesized that mast cell activation (MCA) can contribute to its pathogenesis. Here we describe POTS patients with MCA (MCA+POTS), diagnosed by episodes of flushing and abnormal increases in urine methylhistamine, and compared them to POTS patients with episodic flushing but normal urine methylhistamine and to normal healthy age-matched female controls. MCA+POTS patients were characterized by episodes of flushing, shortness of breath, headache, lightheadedness, excessive diuresis, and gastrointestinal symptoms such as diarrhea, nausea, and vomiting. Triggering events include long-term standing, exercise, premenstrual cycle, meals, and sexual intercourse. In addition, patients were disabled by orthostatic intolerance and a characteristic hyperadrenergic response to posture, with orthostatic tachycardia (from 79+/-4 to 114+/-6 bpm), increased systolic blood pressure on standing (from 117+/-5 to 126+/-7 mm Hg versus no change in POTS controls), increased systolic blood pressure at the end of phase II of the Valsalva maneuver (157+/-12 versus 117+/-9 in normal controls and 119+/-7 mm Hg in POTS; P=0.048), and an exaggerated phase IV blood pressure overshoot (50+/-10 versus 17+/-3 mm Hg in normal controls; P<0.05). In conclusion, MCA should be considered in patients with POTS presenting with flushing. These patients often present with a typical hyperadrenergic response, but beta-blockers should be used with great caution, if at all, and treatment directed against mast cell mediators may be required.

Adrenergic beta-Antagonists↗
PubMed2005

Relevance of adjusted cut-off values in commercial serological immunoassays for Helicobacter pylori infection in children.

We assessed the sensitivity and specificity of H. pylori IgG and IgA with a commercial immunoassay performed in Chile and a second non-commercial immunoassay performed in a reference laboratory in the United States, in serum of 80 children and adults referred for gastrointestinal endoscopies in a developing country. Overall, 56% of the patients were infected with H. pylori based on rapid urease test and staining techniques on gastric biopsies. When Receiver Operator Curves (ROC) were developed, the sensitivity and specificity were similar for IgG and IgA. Both immunoassays exhibited better specificity, positive and negative predictive value (NPV) in children than in adults when cut-off values were corrected according to the local population than when they were assessed using the cut-off values pre-defined in other populations. These results underline the need to establish more precise cut-off values corrected in the local populations where assessments of antibodies as diagnostic markers of H. pylori infection are planning.

Adolescent↗
PubMed2005

'Word-learning wizardry' at 1;6.

This article explores whether infants are able to learn words as rapidly as has been reported for preschoolers. Sixty-four infants aged 1;6 were taught labels for either two moving images or two still images. Each image-label pair was presented three times, after which comprehension was assessed using an adaptation of the intermodal preferential looking paradigm. Three repetitions of each label were found to be sufficient for learning to occur, fewer than has previously been reported for infants under two years. Moreover, contrary to a previous finding, learning was equally rapid for infants who were taught labels for moving versus still images. The findings indicate that infants in the early stages of acquiring a vocabulary learn new word-referent associations with ease, and that the learning conditions that allow such learning are less restricted that was previously believed.

Child Language↗
PubMed2004

[Congenital hepatic fibrosis. Report of five cases].

BACKGROUND: Congenital hepatic fibrosis (CHF) is an autosomic dominant disease that has been associated with polycystic kidney disease. AIM: To describe the medical management of 5 children with CHF and to evaluate the presence and extension of the associated renal disease. PATIENTS AND METHODS: Retrospective review of the medical charts of 5 children with CHF, aged 2 to 14 years. RESULTS: Three children presented autosomic recessive polycystic kidney disease, which was diagnosed before the appearance of liver disease manifestations. They presented a more severe liver damage, with a more aggressive clinical course requiring use of transjugular intrahepatic porto-systemic shunts (TIPS) or surgical porto-systemic shunts to control portal hypertension. The other two children, in whom the diagnosed was based on asymptomatic hepatomegaly, had normal renal function and structure with a more benign clinical course. CONCLUSIONS: The diagnosis of CHF should be suspected not only in children with polycystic kidney disease but in those children with persistent, hard consistency, left lobe predominance hepatomegaly.

Adolescent↗
PubMed2003

[Cholelithiasis in children: a clinical and morphological study].

BACKGROUND: The use of ultrasonography increased the frequency of diagnosis of cholelithiasis in childhood. AIM: To determine the clinical and laboratory features and follow up of children with biliary stones. PATIENTS AND METHODS: Twenty six children (13 male, aged 1 month to 14 years) were prospectively enrolled. RESULTS: Nine children had a past medical history of factors potentially predisposing to stones. A clinical presentation with vomiting (50%), abdominal pain (46%) and jaundice (23%) was the most common indication for surgery. The diagnosis was based on abdominal ultrasound in all children. Cholecystectomy was performed in 15 children (laparoscopy in 13 and open surgery in 2). Children who underwent surgery were older than those who did not undergo surgery (p < 0.001), but they did not have differences in liver function tests. Eight children had pigmented stones and seven had cholesterol stones. CONCLUSIONS: In our patients, neither family history nor laboratory tests were useful in the diagnosis as well as in the clinical decision of surgery, which was based on symptoms. The presence of cholesterol stones in a high proportion of these children may be a unique situation in Chile, considering the high prevalence of this disease in the adult population.

Adolescent↗
PubMed2003

[Polysomnographic abnormalities in infants with gastroesophageal reflux].

BACKGROUND: Infant apnea is a common problem that conveys significant burden to families and physicians. Its temporal relationship with gastroesophageal reflux (GER) is controversial. AIM: To establish whether infants with GER of different magnitude have a higher incidence of respiratory events than children without GER. PATIENTS AND METHODS: 146 consecutive patients were evaluated with polisomnography (PSG) and with an esophageal pH probe. Those infants without GER episodes or with an esophageal pH below 4.0 in less than 5% of total sleep time were considered as physiologic GER (Group I), between 5-10% as mild GER (Group II), and over 10% as severe GER (Group III). These groups were evaluated for demographic and polysomnographic characteristics. RESULTS: There were no differences in the demographic and global PSG characteristics neither in oxymetry, heart rate or electroencephalographic abnormalities. Group III infants had a higher percentage of active sleep compared to infants of Group I (p < 0.05) and higher incidence of central pauses and apneas compared to infants of Group I (p < 0.05). CONCLUSIONS: The presence of severe GER may modify the sleep pattern in infants, increasing the percentage of active sleep. The presence of central pauses and apneas in infants with severe GER suggest an association between the inmaturity of the respiratory centers and the adaptation of the anti-reflux mechanisms.

Apnea↗
PubMed2002

Revising the Competitiveness Index using factor analysis.

The Competitiveness Index is a 20-item true-false measure designed to assess the desire to win in interpersonal situations. To develop a more psychometrically sound form of the scale, 213 undergraduates were administered the original form and a modified version containing a 5-point Likert-type scale. An initial principal component analysis using a varimax rotation of the modified version yielded a four-factor solution accounting for 54.5% of the explained variance. Based on a subsequent reliability analysis. six items were dropped from the modified scale. A second analysis produced a two-factor solution accounting for 54.1% of the explained variance. Both factors (Enjoyment of Competition and Contentiousness) formed reliable subscales. The 14-item Revised Competitiveness Index had high internal consistency and was positively correlated with the original Competitiveness Index, the competitiveness subscales of the Work and Family Orientation Questionnaire, the Sports Orientation Questionnaire, and the Nach Naff measure of Need for Achievement.

Adolescent↗
PubMed2002

[Correlation between phenotype and genotype in a group of patients with cystic fibrosis].

BACKGROUND: Cystic fibrosis (CF) is the most common lethal autosomic disease in Caucasians, with a global incidence of 1:3000 newborns. More than 900 mutations have been described, involving the Cystic Fibrosis Transmembrane Regulator (CFTR). The delta F508 mutation is present in 60% of alleles studied worldwide. AIM: To report 25 patients with cystic fibrosis in whom a genetic study was done. MATERIAL AND METHODS: Twenty five patients (14 men, aged between 18 months and 25 years) with a diagnosis of cystic fibrosis based on clinical features plus two abnormal sweat tests are reported. The genetic study considered the 20 most common mutations in cystic fibrosis and was done in genomic DNA of peripheral lymphocytes, by polymerase chain reaction. RESULTS: A mutation was found in 75% of analyzed alleles. delta F508 was present in 50% of cases (delta F508/delta F508 in 8 and delta F508/other in 11). When delta F508 was present, pancreatic insufficiency was always a feature and nutritional status was worse. Respiratory involvement was variable, both for homozygous and heterozygous cases. Other severe mutations such as W128X and G542X were related to clinical manifestations similar to those found in delta F508 mutation. Diagnosis was made before six months of age in 12 patients. The clinical presentation was meconium ileus and there was a family history of the disease in most cases. The majority of cases of early diagnosis presented severe mutations, but milder respiratory symptoms and lesser nutritional compromise at the time of assessment. CONCLUSIONS: Most patients studied had a severe cystic fibrosis mutation, which was associated with more severe respiratory, pancreatic and nutritional involvement. The early diagnosis of the disease, which would allow to improve the prognosis and the quality of life, must be emphasized.

Adolescent↗
PubMedDate not supplied

Efficiency of new fungal cellulase systems in boosting enzymatic degradation of barley straw lignocellulose.

This study examined the cellulytic effects on steam-pretreated barley straw of cellulose-degrading enzyme systems from the five thermophilic fungi Chaetomium thermophilum, Thielavia terrestris, Thermoascus aurantiacus, Corynascus thermophilus, and Myceliophthora thermophila and from the mesophile Penicillum funiculosum. The catalytic glucose release was compared after treatments with each of the crude enzyme systems when added to a benchmark blend of a commercial cellulase product, Celluclast, derived from Trichoderma reesei and a beta-glucosidase, Novozym 188, from Aspergillus niger. The enzymatic treatments were evaluated in an experimental design template comprising a span of pH (3.5-6.5) and temperature (35-65 degrees C) reaction combinations. The addition to Celluclast + Novozym 188 of low dosages of the crude enzyme systems, corresponding to 10 wt % of the total enzyme protein load, increased the catalytic glucose yields significantly as compared to those obtained with the benchmark Celluclast + Novozyme 188 blend. A comparison of glucose yields obtained on steam-pretreated barley straw and microcrystalline cellulose, Avicel, indicated that the yield improvements were mainly due to the presence of highly active endoglucanase activity/activities in the experimental enzyme preparations. The data demonstrated the feasibility of boosting the widely studied T. reeseicellulase enzyme system with additional enzymatic activity to achieve faster lignocellulose degradation. We conclude that this supplementation strategy appears feasible as a first step in identifying truly promising fungal enzyme sources for fast development of improved, commercially viable, enzyme preparations for lignocellulose degradation.

Ascomycota↗