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R Malekzadeh

Publications and source records attributed to R Malekzadeh.

At least 19 recordsLinked to original sources
PubMed2024

Long-term exposure to particulate matter and all-cause and cause-specific mortality in an analysis of multiple Asian cohorts.

BACKGROUND: Exposure to ambient air pollution is associated with a significant number of deaths. Much of the evidence associating air pollution with adverse effects is from North American and Europe, partially due to incomplete data in other regions limiting location specific examinations. The aim of the current paper is to leverage satellite derived air quality data to examine the relationship between ambient particulate matter and all-cause and cause-specific mortality in Asia. METHODS: Six cohorts from the Asia Cohort Consortium provided residential information for participants, recruited between 1991 and 2008, across six countries (Bangladesh, India, Iran, Japan, South Korea, and Taiwan). Ambient particulate material (PM2·5) levels for the year of enrolment (or 1998 if enrolled earlier) were assigned utilizing satellite and sensor-based maps. Cox proportional models were used to examine the association between ambient air pollution and all-cause and cause-specific mortality (all cancer, lung cancer, cardiovascular and lung disease). Models were additionally adjusted for urbanicity (representing urban and built characteristics) and stratified by smoking status in secondary analyses. Country-specific findings were pooled via random-effects meta-analysis. FINDINGS: More than 300,000 participants across six cohorts were included, representing more than 4-million-person years. A positive relationship was observed between a 5 µg/m (Dockery et al., 1993) increase in PM2·5 and cardiovascular mortality (HR: 1·06, 95 % CI: 0.99, 1·13). The additional adjustment for urbanicity resulted in increased associations between PM2.5 and mortality outcomes, including all-cause mortality (1·04, 95 % CI: 0·97, 1·11). Results were generally similar regardless of whether one was a current, never, or ex-smoker. INTERPRETATION: Using satellite and remote sensing technology we showed that associations between PM2.5 and all-cause and cause-specific Hazard Ratios estimated are similar to those reported for U.S. and European cohorts. FUNDING: This project was supported by the Health Effects Institute. Grant number #4963-RFA/18-5. Specific funding support for individual cohorts is described in the Acknowledgements.

Humans↗
PubMed2006

Injection of botulinum toxin before pneumatic dilatation in achalasia treatment: a randomized-controlled trial.

BACKGROUND: Pneumatic dilatation is the first line therapy in achalasia, but half of patients relapse within 5 years of therapy and require further dilatations. AIM: To assess whether botulinum toxin injection before pneumatic dilatation is superior to pneumatic dilatation alone in achalasia patients. METHODS: Newly diagnosed achalasia patients were randomly assigned to receive botulinum toxin 1 month before pneumatic dilatation (botulinum toxin-pneumatic dilatation group: 27 patients with median age of 38) or to undergo pneumatic dilatation alone (pneumatic dilatation group: 27 patients with median age of 30). Response to therapy was assessed by clinical and objective methods at various intervals. RESULTS: One-year remission rate of patients in botulinum toxin-pneumatic dilatation group was 77% compared with 62% in pneumatic dilatation group (P = 0.1). In pneumatic dilatation group, the oesophageal barium volume significantly (P < 0.001) decreased at 1 month, but this reduction did not persist over 1-year follow-up. Botulinum toxin-pneumatic dilatation group showed a significant (P < 0.001) reduction in barium volume at the various times intervals post-treatment. In the botulinum toxin-pneumatic dilatation group, 10/11 (91%) patients over 40 were in remission at 1 year, comparing with only five of nine (55%) cases in pneumatic dilatation group (P = 0.07). CONCLUSION: Injection of botulinum toxin before pneumatic dilatation does not significantly enhance the efficacy of pneumatic dilatation.

Adult↗
PubMed2006

Percutaneous needle aspiration, injection, and reaspiration with or without benzimidazole coverage for uncomplicated hepatic hydatid cysts.

BACKGROUND: Hepatic hydatid cyst is an important public health problem in parts of the world where dogs are used for cattle breeding. Management of uncomplicated hepatic hydatid cysts is currently surgical. However, the puncture, aspiration, injection, and re-aspiration (PAIR) method with or without benzimidazole coverage has appeared as an alternative to surgery over the past decade. OBJECTIVES: To assess the benefits and harms of PAIR with or without benzimidazole coverage for patients with uncomplicated hepatic hydatid cyst in comparison with sham/no intervention, surgery, or medical treatment. SEARCH STRATEGY: The Cochrane Hepato-Biliary Group Controlled Trials Register, The Cochrane Controlled Trials Register in The Cochrane Library, MEDLINE, EMBASE, DARE, and ACP Journal Club and full text searches were combined (all searched October 2004). Reference lists of pertinent studies and other identified literature were scanned. Researchers in the field were contacted. SELECTION CRITERIA: Only randomised clinical trials using the PAIR method with or without benzimidazole coverage as the experimental treatment of uncomplicated hepatic hydatid cyst (ie, hepatic hydatid cysts which are not infected and do not have any communication with the biliary tree or other viscera) versus no intervention, sham puncture (ie, performing all steps for puncture, pretending that PAIR is being performed, but actually not performing the procedure proper), surgery, or chemotherapy were included. DATA COLLECTION AND ANALYSIS: Data were independently extracted and methodological quality of each trial was assessed by the authors. Principal authors of the trials were contacted to retrieve missing data. MAIN RESULTS: We found no randomised clinical trials comparing PAIR versus no or sham intervention. We identified only two randomised clinical trials, one comparing PAIR versus surgical treatment (n = 50) and the other comparing PAIR (with or without albendazole) versus albendazole alone (n = 30). Both trials were graded as 'adequate' for allocation concealment; however, generation of allocation sequence and blinding methods were 'unclear' in both of them. Compared to surgery, PAIR plus albendazole obtain similar cyst disappearance and mean cyst diameter with fewer adverse events (32% versus 84%, P < 0.001) and fewer days in hospital (mean + SD) ( 4.2 + 1.5 versus 12.7 + 6.5 days, P < 0.001). Compared to albendazole, PAIR with or without albendazole obtain significantly more often (P < 0.01) cyst reduction and symptomatic relief. AUTHORS' CONCLUSIONS: PAIR seems promising, but there is insufficient evidence to support or refute PAIR with or without benzimidazole coverage for treating patients with uncomplicated hepatic hydatid cyst. Further well-designed randomised clinical trials are necessary to address the topic.

Albendazole↗
PubMed2006

Validity and reliability of a new food frequency questionnaire compared to 24 h recalls and biochemical measurements: pilot phase of Golestan cohort study of esophageal cancer.

BACKGROUND: A pilot study was carried out to evaluate validity and reproducibility of a food frequency questionnaire (FFQ), which was designed to be used in a prospective cohort study in a population at high risk for esophageal cancer in northern Iran. METHODS: The FFQ was administered four times to 131 subjects, aged 35-65 years, of both sexes. Twelve 24-h dietary recalls for two consecutive days were administered monthly during 1 year and used as a reference method. The excretion of nitrogen was measured on four 24-h urine samples, and plasma levels of beta-carotene, retinol, vitamin C and alpha-tocopherol was measured from two time points. Relative validity of FFQ and 24-h diet recall was assessed by comparing nutrient intake derived from both methods with the urinary nitrogen and plasma levels of beta-carotene, retinol, vitamin C and alpha-tocopherol. RESULTS: Correlation coefficients comparing energy and nutrients intake based on the mean of the four FFQ and the mean of twelve 24-h diet recalls were 0.75 for total energy, 0.75 for carbohydrates, 0.76 for proteins and 0.65 for fat. Correlation coefficients between the FFQ-based intake and serum levels of beta-carotene, retinol, vitamin C and vitamin E/alpha-tocopherol were 0.37, 0.32, 0.35 and 0.06, respectively. Correlation coefficients between urinary nitrogen and FFQ-based protein intake ranged from 0.23 to 0.35. Intraclass correlation coefficients used to measure reproducibility of FFQ ranged from 0.66 to 0.89. CONCLUSION: We found that the FFQ provides valid and reliable measurements of habitual intake for energy and most of the nutrients studied.

Adult↗
PubMed2006

Patterns of K-ras mutation in colorectal carcinomas from Iran and Italy (a Gruppo Oncologico dell'Italia Meridionale study): influence of microsatellite instability status and country of origin.

BACKGROUND: K-ras mutations are a key step in colorectal cancer progression. Such mutations have been widely studied in case series from Western countries but there are few data on the rate and spectrum of mutations in tumors from countries where the epidemiological features of the disease are different. PATIENTS AND METHODS: Tumor samples from 182 Iranian colorectal cancer patients (170 sporadic cases and 12 HNPCC cases) were screened for K-ras mutations at codons 12, 13 and 61 by sequencing analysis. The cases were also characterized for microsatellite instability at mononucleotide repeats by PCR and fragment analysis, and classified according to microsatellite instability status. The frequency and the spectrum of K-ras mutations were compared with those observed in a series of colorectal cancer patients from Italy. RESULTS: K-ras mutations were observed in 68/182 (37.4%) cases. Mutation frequencies were similar in HNPCC-associated, sporadic MSI-H and sporadic microsatellite-stable (MSS) tumors. However, the G13D substitution was more frequent in HNPCC (3/4, 75%) and sporadic MSI-H (7/11, 63.6%) tumors compared to sporadic MSS tumors (11/53, 20.4%) (P <0.01). Comparison of mutations in the two series from Iran and Italy showed a significantly higher frequency of G13D among Italian patients. CONCLUSIONS: While the frequency of K-ras mutations could be similar, the mutational spectrum could be differentially influenced by genetic and environmental factors.

Codon↗
PubMed2005

The effect of fluoxetine in patients with pain and constipation-predominant irritable bowel syndrome: a double-blind randomized-controlled study.

BACKGROUND: Irritable bowel syndrome has been treated with selective serotonin reuptake inhibitors but there is not enough evidence from controlled trials to prove their effectiveness. AIM: To compare the effects of fluoxetine and placebo in the treatment of pain and constipation-predominant irritable bowel syndrome in a double-blind randomized-controlled trial. METHODS: Forty-four cases meeting Rome II criteria for irritable bowel syndrome with predominance of pain and constipation were included in this study. Organic causes were ruled out by detailed history, physical examination, laboratory tests and colonoscopy. Participants were then randomly assigned to receive either fluoxetine or placebo for 12 weeks. Symptoms addressed by the Rome II criteria were recorded during treatment and 4 weeks after termination of treatment. RESULTS: Fluoxetine was significantly more effective than placebo in decreasing abdominal discomfort, relieving feeling and sense of bloating, increasing frequency of bowel movements and decreasing consistency of stool. Mean number of symptoms per patient decreased from 4.6 to 0.7 in the fluoxetine group vs. 4.5 to 2.9 in controls (P < 0.001). CONCLUSIONS: Fluoxetine is an effective and well-tolerated short-term treatment for pain and constipation-predominant irritable bowel syndrome.

Abdominal Pain↗
PubMed2005

Lower oesophageal sphincter pressure and timed barium oesophagogram: two objective parameters in the non-invasive assessment of primary achalasia.

BACKGROUND: The non-invasive assessment of primary achalasia is not precise. AIM: To compare investigations before and 1 month after balloon dilation in achalasia. METHODS: Fifty-two patients with primary achalasia were enrolled. Subjective and objective variables of oesophageal functions were analysed before and 1 month after balloon dilation. RESULTS: The mean predilation symptom score, lower oesophageal sphincter pressure, height and volume of barium at 5 min were 7.7 +/- 2.6, 62.0 +/- 25.1 mmHg, 9.2 +/- 6.1 cm and 53.2 +/- 49.8 mL respectively; the mean postdilation values were 3.0 +/- 3.0, 34.1 +/- 12.5 mmHg, 7.9 +/- 5.1 cm and 28.0 +/- 30.1 mL respectively. The before dilation volume of barium at 5 min correlates significantly with lower oesophageal sphincter pressure (P < 0.01). The mean symptom scores, lower oesophageal sphincter pressure and volume of barium at 5 min dropped significantly after intervention (P < 0.01), but the reduction in barium height at 5 min was not significant. The percentage changes in volume at 5 min significantly predicted the percentage changes in lower oesophageal sphincter pressure (P < 0.01). CONCLUSIONS: The volume of barium retention at 5 min can predict the lower oesophageal sphincter pressure before and after balloon dilation in primary achalasia. This could be used as a non-invasive objective tool for initial and post-dilation assessment.

Adult↗
PubMed2005

Golestan cohort study of oesophageal cancer: feasibility and first results.

To investigate the incidence of oesophageal cancer (EC) in the Golestan province of North-East Iran, we invited 1349 rural and urban inhabitants of Golestan province aged 35-80 to undergo extensive lifestyle interviews and to provide biological samples. The interview was repeated on a subset of 130 participants to assess reliability of questionnaire and medical information. Temperature at which tea was consumed was measured on two occasions by 110 subjects. Samples of rice, wheat and sorghum were tested for fumonisin contamination. An active follow-up was carried out after 6 and 12 months. A total of 1057 subjects (610 women and 447 men) participated in this feasibility study (78.4% participation rate). Cigarette smoking, opium and alcohol use were reported by 163 (13.8%), 93 (8.8%) and 39 (3.7%) subjects, respectively. Tobacco smoking was correlated with urinary cotinine (kappa = 0.74). Most questionnaire data had kappa > 0.7 in repeat measurements; tea temperature measurement was reliable (kappa = 0.71). No fumonisins were detected in the samples analysed. During the follow-up six subjects were lost (0.6%), two subjects developed EC (one dead, one alive); in all, 13 subjects died (with cause of death known for 11, 84.6%). Conducting a cohort study in Golestan is feasible with reliable information obtained for suspected risk factors; participants can be followed up for EC incidence and mortality.

Adult↗
PubMed2004

Pneumatic balloon dilatation in achalasia: a prospective comparison of safety and efficacy with different balloon diameters.

BACKGROUND: Pneumatic dilatation is considered to be the first line therapy for achalasia, but long-term outcome studies are scarce and limited by their retrospective design. There is also no consensus on the optimal method for performing pneumatic dilation as regard to balloon diameter, amount and the rate inflation pressure. AIM: To address these questions in a large long-term prospective study. METHODS: Over a period of 10 years 262 achalasia patients referred to our centre were enrolled. All patients underwent a pre-treatment clinical evaluation and were followed every 6 months. The first 62 patients (group A) underwent dilatation with initial use of a 35 mm balloon with inflation pressure of 10 psi in 10 seconds (s). In group B (200 patients) we initially used a 30 mm balloon with inflation pressure of 10 psi in 30 s. Dilatation was repeated with incrementally larger balloons (35 and 40 mm) in case of relapse. We used rigiflex balloon and maintained pressure for 60 s after inflation in both groups. RESULTS: Three perforations occurred in group A whereas no perforation took place in Group B. The cumulative proportional remission rate with single dilatation in groups A and B decreased from 83 and 75% in 6 months to 60 and 57% after 30 months of therapy respectively, the differences did not reach statistical significance. In patients who had undergone further dilatations the probability of remaining in remission at 1 year after the first and the second dilatation was 38 and 88% in group A, 20 and 89% in group B respectively. The probability of remaining in remission for 2 years increased from 20% after the first dilatation to 70% after the second dilatation. CONCLUSION: Graded pneumatic balloon dilatation with 30 mm diameter and slower rate of balloon inflation is an effective and safe initial method of therapy for achalasia. The duration of remission can be extended by repeated dilatation with larger size balloon.

Adult↗
PubMed2004

Epidemiologic features of upper gastrointestinal tract cancers in Northeastern Iran.

Previous studies have shown that oesophageal and gastric cancers are the most common causes of cancer death in the Golestan Province, Iran. In 2001, we established Atrak Clinic, a referral clinic for gastrointestinal (GI) diseases in Gonbad, the major city of eastern Golestan, which has permitted, for the first time in this region, endoscopic localisation and histologic examination of upper GI cancers. Among the initial 682 patients seen at Atrak Clinic, 370 were confirmed histologically to have cancer, including 223 (60%) oesophageal squamous cell cancers (ESCC), 22 (6%) oesophageal adenocarcinomas (EAC), 58 (16%) gastric cardia adenocarcinomas (GCA), and 58 (16%) gastric noncardia adenocarcinomas. The proportional occurrence of these four main site-cell type subdivisions of upper GI cancers in Golestan is similar to that seen in Linxian, China, another area of high ESCC incidence, and is markedly different from the current proportions in many Western countries. Questioning of patients about exposure to some known and suspected risk factors for squamous cell oesophageal cancer confirmed a negligible history of consumption of alcohol, little use of cigarettes or nass (tobacco, lime and ash), and a low intake of opium, suggesting that the high rates of ESCC seen in northeastern Iran must have other important risk factors that remain speculative or unknown. Further studies are needed to define more precisely the patterns of upper GI cancer incidence, to test other previously suspected risk factors, and to find new significant risk factors in this high-risk area.

Adenocarcinoma↗
PubMed2004

Low-dose furazolidone in triple and quadruple regimens for Helicobacter pylori eradication.

BACKGROUND: Furazolidone-based regimens for the eradication of Helicobacter pylori are low cost and effective. Unfortunately, the usual dose of furazolidone is not tolerable in many patients. Lower doses of furazolidone are expected to cause fewer adverse effects. AIM: To investigate the efficacy of low-dose furazolidone in the eradication of H. pylori. METHODS: One hundred and fifty patients with duodenal ulcer and H. pylori infection were randomly assigned to one of three treatment groups: omeprazole 20 mg b.d., amoxicillin 1000 mg b.d. and furazolidone 100 mg b.d. for 14 days (OAF); omeprazole 20 mg b.d., amoxicillin 1000 mg b.d., furazolidone 100 mg b.d. and bismuth subcitrate 240 mg b.d. for 14 days (OABF1); or omeprazole 20 mg b.d., amoxicillin 1000 mg b.d., furazolidone 200 mg b.d. and bismuth subcitrate 240 mg b.d. for 14 days (OABF2). RESULTS: Of the 150 patients, 145 completed treatment. The intention-to-treat and per protocol eradication rates were 54% (27/50), 72% (36/50) and 92% (46/50) for the OAF, OABF1 and OABF2 groups, respectively. The OAF and OABF1 groups showed significantly lower eradication rates than the OABF2 group (P<0.001 and P<0.01, respectively). CONCLUSIONS: Triple and quadruple furazolidone-based H. pylori eradication regimens do not yield acceptable success rates when a low dose of furazolidone (100 mg b.d.) is used.

Adult↗
PubMed2004

Coeliac disease in Iranian type I diabetic patients.

BACKGROUND: The association between coeliac disease and type I diabetes mellitus has been evaluated in some previous studies, but its prevalence in Iranian diabetic patients remains unknown. AIM: To evaluate the prevalence of coeliac disease in patients with type I diabetes mellitus in Iran. PATIENTS: A total of 250 consecutive patients (102 male and 148 female) with type I diabetes mellitus. METHODS: Total serum immunoglobulin A level and immunoglobulin A endomysial antibody was measured for all patients. Endoscopy and biopsy of the duodenum were performed for immunoglobulin A endomysial antibody-positive patients and pathologic evaluation was done according to modified Marsh classification. RESULT: The mean age of the patients was 18.7 years (range: 2-55 years). Total serum immunoglobulin A was in the normal range for all patients. Immunoglobulin A endomysial antibody was positive in six (2.4%) patients (all of them were females; P = 0.04). Duodenal biopsy samples revealed grade I in two patients, grade II in three patients and grade IIIb in one patient (modified Marsh classification). Patients with coeliac disease and diabetes mellitus were older than patients with diabetes mellitus alone (mean age: 29.5 years versus 18.4 years; P < 0.001). There was a trend for longer duration of diabetes mellitus in coeliac patients than in patients without it (mean age: 17.3 years versus 12.5 years; P = 0.16). CONCLUSION: The prevalence of coeliac disease in Iranian patients with type I diabetes mellitus is relatively high (2.4%). Since almost half of the patients with coeliac disease are asymptomatic, all patients with type I diabetes mellitus should be screened for coeliac disease regardless of the presence of symptoms, at diagnosis of diabetes mellitus and with regular intervals in the follow up.

Adolescent↗
PubMed2004

Coeliac disease in Middle Eastern countries: a challenge for the evolutionary history of this complex disorder?

About 10,000 years ago domestication and farming of wheat and other cereals developed in the 'Fertile Crescent', an area including modern Turkey, Iraq and Iran. Agriculture then slowly spread from Middle East to Europe. Coeliac disease is the permanent intolerance to dietary gluten, the major protein component of wheat. It has been until relatively recently hypothesised that wheat consumption exerted a negative selective pressure on genes predisposing to coeliac disease, eventually leading to higher coeliac disease frequency in Northeastern Europe because of lack of exposure to cereals. This theory is at variance with recent studies showing that coeliac disease is as common in Middle Eastern countries as in Europe. High prevalence of coeliac disease has been found in Iran, in both the general population and at-risk groups, e.g. patients with irritable bowel syndrome or type 1 diabetes. Clinical manifestations of coeliac disease vary markedly with the age of the patient, the duration and the extent of disease. Clinical studies showed that presentation with non-specific symptoms or no symptoms is as common in the Middle East as in Europe. Wheat represented a major component of the Iranian diet for many centuries and it may be argued that the continuous and high level of exposure to wheat proteins has induced some degree of immune tolerance, leading to milder symptoms that may be misdiagnosed as irritable bowel syndrome or unexplained gastrointestinal disorders. The gluten-free diet represents a real challenge to both patients and clinicians in this area. This is particularly difficult in the absence of any supply for gluten-free diet in Middle Eastern countries.

Celiac Disease↗
PubMed2004

Efficacy of botulinum toxin injection before pneumatic dilatation in patients with idiopathic achalasia.

Graded pneumatic dilatation (PD) is an appropriate long-term therapy and botulinum toxin injection (BT) is a relatively short-term therapy in idiopathic achalasia. Their combination has not been previously scrutinized. This study aimed to evaluate the role of BT in enhancing the efficacy of PD with 30 mm balloons. Patients who underwent PD with 30 mm balloons after botulinum toxin injections and a group of age- and sex-matched controls who were treated only with PD were enrolled in the study. Symptom scores were taken before, 1 month after and then every 3 months after PD. There were no significant differences between the two groups in gender, duration or severity of symptoms. One of the 12 patients in the case group relapsed 30 months after PD but the others were in remission for an average of 25.6 months. In the control group, all the patients relapsed after a mean of 12.6 months and needed a 35-mm PD. The cumulative remission rate was significantly higher in the case group compared with the control group (P < 0.01). The mean symptom score decreased by 76% in the case group (P < 0.001) and 53% in the controls (P < 0.01) at the end of the first month. Neither age, sex, nor duration or severity of symptoms were predictive of patients' responses to treatment. It seems that BT may be a meaningful enhancing factor in long-term efficacy of PD. PD with a 30 mm balloon after a BT session may resolve the need for the future higher grade PD.

Adolescent↗