A psychological approach to learning causal networks

We examine the role of a common cognitive heuristic in unsupervised learning of Bayesian probability networks from data. Human beings perceive a larger association between causal than diagnostic relationships. This psychological principal can be used to orient the arcs within Bayesian networks by prohibiting the direction that is less predictive. The heuristic increased predictive accuracy by an average of 0.51 % percent, a small amount. It also increased total agreement between different network learning algorithms (Max Spanning Tree, Taboo, EQ, SopLeq, and Taboo Order) by 25 %. Prior to use of the heuristic, the multiple raters Kappa between the algorithms was 0.60 (95 % confidence interval, CI, from 0.53 to 0.67) indicating moderate agreement among the networks learned through different algorithms. After the use of the heuristic, the multiple raters Kappa was 0.85 (95 % CI from 0.78 to 0.92). There was a statistically significant increase in agreement between the five algorithms (alpha <?0.05). These data suggest that the heuristic increased agreement between networks learned through use of different algorithms, without loss of predictive accuracy. Additional research is needed to see if findings persist in other data sets and to explain why a heuristic used by humans could improve construct validity of mathematical algorithms.     

Automated Monitoring to Detect H1N1 Symptoms Among Urban, Medicaid-Eligible, Pregnant Women: A Community-Partnered Randomized Controlled Trial

In response to the H1N1 epidemic, we used community health workers to design and implement a randomized controlled trial to test the efficacy of a new automated call-monitoring system for second and third trimester predominantly Medicaid-eligible pregnant women in an urban free standing birth center to promptly detect symptoms of influenza and assure rapid treatment to prevent adverse outcomes from influenza. Daily automated telephone call to second and third trimester pregnant women asking if the woman experienced flu-like symptoms. Calls continued daily until 38 weeks gestation. A community health worker’s voice was used for the automated call recording. Positive responses triggered an immediate referral to a nurse-midwife for prompt treatment with anti-viral medication. Fifty pregnant participants were randomized into daily-automated call group (n = 26) or health information group (n = 24). The automated call group participants ranged in age from 14 to 36 (mean = 23.5, SD = 6.3), 84.7 % identified their race/ethnicity as African-American Non-Hispanic, and 80.7 % were Medicaid-Eligible. In the automated call group, 11.5 % chose to be immunized against H1N1. The mean percent of patients reached daily was 45.1 % (SD = 3.2 %) and at least once every 3 days was 65.1 % (SD = 3.1 %). One pregnant woman in the automated call group contracted H1N1 influenza and received prompt anti-viral treatment without any serious outcomes. Participation in daily-automated telephone calls did not differ significantly between patients younger than 18 years old versus patients 18 years or older. There was also no difference in participation between patients with parity of 0 versus patients with parity ≥1. Participation in daily telephone calls significantly (alpha ≤0.05) increased when a community health worker provided personal follow-up of non-responsive participants. 93.3 % of surveyed pregnant women, who received automated daily calls, recommended to use a similar daily call system in response to a future health crisis. Automated daily phone calls, designed and produced by community health workers, is a feasible, well received strategy to provide urgent health information to an urban, Medicaid-eligible group of pregnant women, regardless of age or parity.     

The outcome of arginase activity inhibition in BALB/c mice hosting Leishmania tropica

Two species of Leishmania (L), L. tropica and L. major, are among the main causative agents of cutaneous leishmaniasis. Arginase (ARG) is an essential enzyme for cell growth, thus an attractive drug target. In this study, we tried to survey the inhibitory impact of ARG by nor-NOHA (N-ω-hydroxy-L-nor-arginine) on in vivo infection caused by L. tropica. BALB/c mice were inoculated with L. tropica^EGFP-LUC (Ltrop) or L. major^EGFP-LUC (Lmj) and then were treated by nor-NOHA. ARG inhibitor only indicated a delay in generation of a cutaneous lesion in inoculated footpad with nor-NOHA-Ltrop and nor-NOHA-Lmj. ARG activity has been significantly reduced in nor-NOHA-Ltrop group. In this group, ARG activity inhibition correlated with increased levels of nitric oxide (NO). In both inoculated mice with Ltrop or Lmj, parasite load showed a significant decrease at later steps during the CL course post-treatment. In vivo bioluminescence intensity did not show any ARG's inhibitory effect on treated-Ltrop. The findings verified that the ARG activity may partially control the L. tropica infection in BALB/c mice through reduction of parasite proliferation and parasite killing through NO generation. This effect is dose-dependent.     

Unique site- and time-specific patterns of recurrence following resection of colorectal carcinoma hepatic metastases in patients staged by FDG-PET

Background/Purpose

We recently reported that patients staged by positron emission tomography (PET) with F-18 fluorodeoxyglucose (FDG) prior to liver resection for metastatic colorectal cancer had an excellent 5-year survival. In this study, the site- and time-specific patterns of recurrence were examined in patients staged by FDG-PET and the results compared to historical literature control data.

Methods

From March 1995 to June 2002, all patients having hepatic resection for colorectal cancer metastases had preoperative FDG-PET. A prospective database was maintained.

Results

One hundred patients were studied; 48 patients had no evidence of recurrence, 30 patients had recurrence within 12 months of resection, and 22 patients had recurrence after 12 months. Seventy percent of patients with recurrence within 1 year of resection had intrahepatic recurrence. Furthermore, 86% of patients with recurrence more than 1 year after resection had extrahepatic recurrence. We reviewed all published case series of conventionally staged patients. This pattern of early recurrence in the liver and later recurrence in extrahepatic sites has not been reported in any of the conventionally staged series.

Conclusions

There is an interesting difference in the pattern of recurrence of FDG-PET-staged patients and conventionally staged patients who undergo liver resection. Several explanations seem possible. One potential explanation requiring further study is that the pattern of recurrence is due to the convergence of two factors—that FDG-PET more effectively detects extrahepatic disease than conventional staging and that liver resection gives a growth spurt to hepatic metastases.     

Metabolic improvement of morbid obese patients following Roux-en-Y gastric bypass surgery: A prospective study in Mashhad,Iran

Background and Aim

Obesity is one of the greatest public health concerns worldwide. Weight loss surgeries have been increased in recent decades due to the world’s epidemic of obesity. The aim of this prospective study is investigating metabolic factors of morbid obese patients following Roux-en-Y gastric bypass surgery.

Methods

This was a nonrandomized prospective cohort study conducted from 2010 to 2013 on 60 consecutive patients who had body mass index (BMI) of more than 40 kg/m² and met the surgical indication criteria of bariatric surgery. Upon discharge, patients were followed in outpatient clinic of Qaem Hospital, Mashhad, Iran, each 3 months for 12 months. Measurement of anthropometric and metabolic indices was done in each postoperative visit.

Results

Mean BMI reduction was 15.26?±?3.45 kg/m² in the patients with an average value of 28.84?±?3.94 (range from 22 to 40 kg/m²), which was significantly lower than the base value (p?<?0.001). After a 12-month follow up, patients had lower low-density lipoprotein, triglycerides, and total cholesterol (p?<?0.001 for all the variables), while achieving a greater high-density lipoprotein (p?=?0.004). An improvement was seen in all of hypertensive patients after a 3-month follow up and blood pressure remained within normal limit in further follow ups. Complete remission was observed in all the patients with obstructive sleep apnea.

Conclusion

It appears reasonable that multidisciplinary treatment including surgical alternatives should be concerned for all morbidly obese patients, considering high rate of failure of conservative medical therapy in this setting.

     

Prevalence of colonic diverticular disease in Southern Iran

Five hundred fifty-six barium enema examinations performed in male and female patients (aged 20–70+years) were studied retrospectively to estimate the prevalence of colonic diverticulosis in southern Iran. The frequency of diverticulosis in all subjects above the age of 20 years was 1.6 per cent, in persons above the age of 50 years, 2.4 per cent, and in persons below the age of 50 years, 1.2 per cent. This is in marked contrast to the high prevalence of the disease in Western countries,e.g., the 20 per cent overall prevalence in the United States. The high dietary fiber intake of the Iranian people may explain the rarity of the disease in Iran.     

Effect of Helicobacter pylori eradication in Iranian patients with functional dyspepsia: a prospective,randomized, placebo-controlled trial

Introduction

Whether patients with functional dyspepsia (FD) should receive Helicobacter pylori (H. pylori) eradication therapy remains controversial. The objective of this trial was to evaluate the effect of H. pylori eradication therapy on dyspeptic symptoms of patients with FD.

Material and methods

A prospective, randomized, placebo-controlled trial of H. pylori eradication for FD was conducted. A total of 720 FD patients diagnosed by Rome III criteria were consecutively enrolled. We randomly assigned 186 H. pylori infected patients with FD to receive quadruple therapy for 14 days and 173 such patients to receive identical-appearing placebos. Severity of abdominal symptoms was assessed with the Glasgow Dyspepsia Severity Score (GDSS), and eradication of H. pylori by ¹³C-urea breath test was evaluated during one year.

Results

The rate of eradication of H. pylori infection was 87.1% in the treatment group and 2.9% in the placebo group at 6 weeks (p = 0.001). The mean GDSS at 12 months was 4.9 ±2.8 in the treatment group, as compared to 5.2 ±3.4 in the placebo group (p = 0.064). The scores in both groups were lower than those at baseline. According to the intention-to-treat analysis, at 12 months, there was no significant difference between groups in the rate of successful treatment (48.6% in the treatment group and 51.2% in the placebo group; p = 0.84). There was no significant difference in mean symptom scores between the two treatment groups at any point during follow-up.

Conclusions

The results of our study provide no evidence that H. pylori eradication leads to relief of symptoms 12 months after treatment, and there is a need for further studies.     

Leishmaniasis recidivans among school children in Bam,South‐east Iran, 1994–2006

Background Leishmaniasis recidivans (LR) is a rare phenomenon in the world with high morbidity in children. Methods Overall 22 838 school children were examined during 1994–2006. Diagnosis was performed by combination of methods as clinical appearance, direct smears, cultures, polymerase chain reaction (PCR) and histology. Results Ninety‐eight cases were diagnosed as LR with duration of lesions varying from 2 to 8 years and diameter of lesions 1–5 cm, yellowish‐brown appearance with papules around or in the scar. Most of the lesions (95%) were on the face. No amastigote was found in direct smears. Identification of nine random isolates by PCR confirmed all species to be L. tropica. Tissue sections showed typical granulomatous reactions with various inflammatory cells but no visible amastigote was seen. Conclusions The presence of LR as an important cause of morbidity has future implications for treatment regimens and immunoprophylaxis.     

The role of positron emission tomography in the management of pancreatic cancer

The role of positron emission tomography (PET) and PET/computed tomography (CT) in the assessment of a patient presenting with cancer of the pancreas is discussed in the overall context of the management of this condition. The clinical limitations persist, with many patients presenting late with unresectable disease and poor prospects for novel drug therapies. PET and PET/CT are best at diagnosing and staging but are relatively inefficient in the detection of nodal disease. The detection of late disease manifestations such as metastatic spread is often of little clinical consequence. PET/CT may be considered as a first-line imaging investigation but evidence for this approach needs to accrue. Overall detection sensitivity at diagnosis varies between 90% and 95% and specificity from 82% to 100%, whereas for staging, sensitivity data vary from 61% to 100% and specificity data from 67% to 100%.     

The Effect of Altitude on Breaking Seed Dormancy and Stimulation of Seed Germination of Persian Hogweed (Heracleum Persicum)

Persian hogweed is a perennial herb and aromatic plant which has pharmaceutical and fodder values, and the main propagation method of this species is seed. The goal of this study was to investigate the effect of altitude on breaking dormancy and stimulate seed germination of this species. The study was designed and carried out using the test of seed analysis. For our purpose, seeds were collected from three different altitudes (1700, 2200, 2700 masl) in Kojoor area. After initial purification, germination percent (GP) and speed (GS) of each elevation were determined by cold stratification compared to control. According to results, control seeds did not germinate, showing that the seeds of this species need to be treated. Statistical analysis of results showed that there are significant differences between GP and GS of each elevation, as seeds of higher elevation had slower and less germination in longer periods. So, changes in elevation are an effective factor on seed germination characteristics of this species and this factor has to be considered in seed preparation and restoration with this species.