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Biomedical subjects

Mohammad Farhadi

Publications and source records attributed to Mohammad Farhadi.

10 recordsLinked to original sources
PubMed2005

GJB2 mutations: passage through Iran.

Hereditary hearing loss (HHL) is a very common disorder. When inherited in an autosomal recessive manner, it typically presents as an isolated finding. Interestingly and unexpectedly, in spite of extreme heterogeneity, mutations in one gene, GJB2, are the most common cause of congenital severe-to-profound deafness in many different populations. In this study, we assessed the contributions made by GJB2 mutations and chromosome 13 g.1777179_2085947del (the deletion more commonly known as del (GJB6-D13S1830) that includes a portion of GJB6 and is hereafter called Delta(GJB6-D13S1830)) to the autosomal recessive non-syndromic deafness (ARNSD) genetic load in Iran. Probands from 664 different nuclear families were investigated. GJB2-related deafness was found in 111 families (16.7%). The carrier frequency of the 35delG mutation showed a geographic variation that is supported by studies in neighboring countries. Delta(GJB6-D13S1830) was not found. Our prevalence data for GJB2-related deafness reveal a geographic pattern that mirrors the south-to-north European gradient and supports a founder effect in southeastern Europe.

Connexin 26↗
PubMed2005

Human papillomavirus in squamous cell carcinoma of esophagus in a high-risk population.

AIM: To investigate the relation of human papillomavirus (HPV) and esophageal squamous cell carcinoma (ESCC) in Iranian patients as compared to normal controls. METHODS: Using MY09/MY11 consensus primers, we compared the prevalence of a HPV L1 gene in tumor tissues from 38 ESCC cases and biopsied tissues from 38 endoscopically normal Iranian individuals. We also compared the presence of HPV16 and HPV18 in the same samples using type-specific E6/E7 primers. RESULTS: Fourteen (36.8%) of the 38 ESCC samples but only 5 (13.2%) of the 38 control samples were positive for the HPV L1 gene (P = 0.02). Five (13.2%) of the ESCC samples but none of the control samples were positive for the HPV16 E6/E7 gene (P = 0.05). Three (7.9%) of the ESCC samples and 5 (13.2%) of the control samples were positive for the HPV18 E6/E7 gene (P = 0.71). CONCLUSION: Our data are consistent with HPV DNA studies conducted in other high-risk areas for ESCC. HPV should be considered as a potential factor contributing to the high incidence of ESCC in Iran and other high-incidence areas of the world.

Adult↗
PubMed2005

Blink reflex and auditory speech perception in prelingually cochlear-implanted children.

CONCLUSION: The results of this study show that R- prelingually cochlear-implanted children are not optimal candidates for cochlear implantation. However, if this group are implanted, other rehabilitation methods should be incorporated into their rehabilitation program in order to achieve better results and maximize the efficacy of their prosthesis. OBJECTIVE: To demonstrate that the blink reflex or auropalpebral reflex evaluation can be used as a prognostic factor for the assessment of auditory and speech perception levels in prelingually cochlear-implanted children. MATERIAL AND METHODS: In an observational, analytical, prospective study conducted at a single cochlear implant rehabilitation center in 85 prelingually cochlear-implanted children, the presence or absence of the blink reflex (BR) was evaluated and the results of auditory and speech perception tests were compared between reflex-positive (R+) and reflex-negative (R-) patients. To obtain the BR, four electrodes were applied in both the Nucleus and MED-EL systems and then stimulated by means of current levels higher than the previously detected most comfortable level of the patient until the reflex appeared. Auditory and speech perception levels were measured using the vowels-confusion test and the categorization of auditory perception scale. RESULTS: The mean results of auditory and speech perception tests were significantly higher in R+ compared to R- patients.

Auditory Threshold↗
PubMed2003

High prevalence of coeliac disease in apparently healthy Iranian blood donors.

BACKGROUND/OBJECTIVE: Studies about the prevalence of coeliac disease in countries in western Asia are scarce and there is no study on the prevalence of coeliac disease in Iran. The aim of this study was to determine the prevalence of coeliac in healthy, Iranian, blood donors. STUDY DESIGN AND METHODS: Blood samples were obtained from 2000 apparently healthy blood donors (1580 males, 420 females; mean age 35.5 years, range 18-65 years) at the Tehran Blood Donation Centre during a 4 month period from November 1998 through February 1999. Total serum IgA was measured in all donors, and IgA deficient cases were excluded. All cases were analysed for IgA anti-gliadin (AGA) by an ELISA test and those with positive results were tested for IgA anti-endomysium antibody (EMA) using immunofluorescence. All donors who had a positive serology for both AGA and EMA underwent small intestinal biopsy. The biopsy samples were classified according to revised Marsh criteria (UEGW 2001). RESULTS: Forty-nine cases showed positive IgA AGA (38 males and 11 females, mean age 38.6 years). Of the 49 AGA positive cases 12 were EMA positive. All subjects with positive serology (both AGA and EMA) were found to have small bowel biopsies compatible with gluten sensitive enteropathy. Three of 12 had Marsh I, 4/12 Marsh II and 5/12 showed a Marsh IIIa lesion. CONCLUSION: The minimum prevalence of gluten sensitivity among apparently healthy urban Iranian blood donors is 1/166. Further epidemiological studies in adults from the general population and in high risk groups seems indicated.

Adolescent↗
PubMed2002

GJB2 mutations in Iranians with autosomal recessive non-syndromic sensorineural hearing loss.

Hereditary hearing loss (HHL) is an extremely common disorder. About 70% of HHL is non-syndromic, with autosomal recessive forms accounting for approximately 85% of the genetic load. Although very heterogeneous, the most common cause of HHL in many different world populations is mutations of GJB2, a gene that encodes the gap junction protein connexin 26 (Cx26). This study investigates the contribution of GJB2 to the autosomal recessive non-syndromic deafness (ARNSD) load in the Iranian population. One hundred sixty eight persons from 83 families were studied. GJB2-related deafness was diagnosed in 9 families (4, 35delG homozygotes; 3, 35delG compound heterozygotes; 1, W24X homozygote; 1, non-35delG compound heterozygote). The carrier frequency of the 35delG allele in this population was approximately 1% (1/83). Because the relative frequency of Cx26 mutations is much less than in the other populations, it is possible that mutations in other genes play a major role in ARNSD in Iran.

Connexin 26↗
PubMed2002

The effects of age on auditory speech perception development in cochlear-implanted prelingually deaf children.

One of the most important factors in auditory speech perception of cochlear-implanted children is age. The goal of this study was to compare auditory speech perception among children implanted from 6 different age groups: 0 to 3, 4 to 5, 6 to 7, 8 to 9, 10 to 11, and >12 years. The subjects of this study were matched based on socioeconomic status, residual hearing before cochlear implantation, the kinds of cochlear implant device, speech processing strategy, communication mode after implantation, and primary language in family. All of them have used the device minimally for 2 years. The subjects were tested with a range of closed and open-set auditory speech perception tests, and the levels of auditory speech perception in different age groups were compared. Results showed that the children who received an implant at 0 to 3 years of age had maximum auditory speech perception.

Adolescent↗
PubMed2002

Three familial cases of Michel's aplasia.

Complete agenesis of the bony labyrinth, first described by Michel, represents the most severe form of inner ear defect. A search of the literature yielded only one report of this rare anomaly, affecting two siblings. Three familial cases of bilateral inner ear aplasia are reported here, and the probable inheritance pattern of this condition is discussed.

Child↗
PubMed2002

Microtumor growth initiates angiogenic sprouting with simultaneous expression of VEGF, VEGF receptor-2, and angiopoietin-2.

Tumors have been thought to initiate as avascular aggregates of malignant cells that only later induce vascularization. Recently, this classic concept of tumor angiogenesis has been challenged by the suggestion that tumor cells grow by co-opting preexisting host vessels and thus initiate as well-vascularized tumors without triggering angiogenesis. To discriminate between these two mechanisms, we have used intravital epifluorescence microscopy and multi-photon laser scanning confocal microscopy to visualize C6 microglioma vascularization and tumor cell behavior. To address the mechanisms underlying tumor initiation, we assessed the expression of VEGF, VEGF receptor-2 (VEGFR-2), and angiopoietin-2 (Ang-2), as well as endothelial cell proliferation. We show that multicellular aggregates (<< 1 mm(3)) initiate vascular growth by angiogenic sprouting via the simultaneous expression of VEGFR-2 and Ang-2 by host and tumor endothelium. Host blood vessels are not co-opted by tumor cells but rather are used as trails for tumor cell invasion of the host tissue. Our data further suggest that the established microvasculature of growing tumors is characterized by a continuous vascular remodeling, putatively mediated by the expression of VEGF and Ang-2. The results of this study suggest a new concept of vascular tumor initiation that may have important implications for the clinical application of antiangiogenic strategies.

Angiopoietin-2↗
PubMedDate not supplied

Cochlear implantation in Mondini dysplasia.

The use of cochlear implantation to treat patients with inner ear malformations such as Mondini dysplasia has been increasingly successful. Until now, conventional hearing aids in these patients have not performed well. Consequently, the hearing problem for patients with this condition has been somewhat improved with the use of cochlear implants. Various results of cochlear implantation have been reported in these patients so far. This is a report of 5 patients with Mondini malformation who have undergone cochlear implant surgery.

Child, Preschool↗