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Biomedical subjects

M Azimi

Publications and source records attributed to M Azimi.

13 recordsLinked to original sources
PubMed2001

Universal newborn screening for Hb H disease in California.

Newborn screening is an accepted public health measure to ensure that appropriate health care is provided in a timely manner to infants with hereditary/metabolic disorders. Alpha-thalassemia is a common hemoglobin (Hb) disorder, and causes Hb H (beta4) disease, and usually fatal homozygous alpha(0)-thalassemia, also known as Hb Bart's (gamma4) hydrops fetalis syndrome. In 1996, the State of California began to investigate the feasibility of universal newborn screening for Hb H disease. Initial screening was done on blood samples obtained by heel pricks from newborns, and stored as dried blood spots on filter paper. Hb Bart's levels were measured as fast-moving Hb by automated high-performance liquid chromatography (HPLC) identical to that currently used in newborn screening for sickle cell disease. Subsequent confirmation of Hb H disease was done by DNA-based diagnostics for alpha-globin genotyping. A criterion of 25% or more Hb Bart's as determined by HPLC detects most, if not all cases of Hb H disease, and few cases of alpha-thalassemia trait. From January, 1998, through June, 2000, 89 newborns were found to have Hb H disease. The overall prevalence for Hb H disease among all newborns in California is approximately 1 per 15,000. Implementation of this program to existing newborn hemoglobinopathy screening in populations with significant proportions of southeast Asians is recommended. The correct diagnosis would allow affected infants to be properly cared for, and would also raise awareness for the prevention of homozygous alpha(0)-thalassemia or Hb Bart's hydrops fetalis syndrome.

Asia, Southeastern↗
PubMed1999

Overexpression of the EphA2 tyrosine kinase in prostate cancer.

BACKGROUND: Molecules that are highly expressed by human prostate cancers may serve as therapeutically relevant targets or tumor markers. Tyrosine kinases are frequently overexpressed in metastatic tumor cells and this prompted us to screen for tyrosine kinases that are overexpressed in prostate cancer cells. METHODS: Expression levels of the EphA2 receptor tyrosine kinase were determined by Western blot analysis in canine and human prostate cancer cell lines and in immortalized and transformed variants of 267B1 prostatic epithelial cells. EphA2 levels in benign human prostate and prostate cancers were also determined in formalin-fixed, paraffin-embedded tissues using immunohistochemical staining. RESULTS: Metastatic prostate cancer cells overexpressed EphA2 by 10-100 fold as compared with non-invasive prostatic epithelial cells. EphA2 immunoreactivity in vivo was also significantly greater in human prostate cancers as compared with benign prostate epithelium. CONCLUSIONS: The EphA2 receptor tyrosine kinase is differentially expressed in human and canine prostate cancer cell lines and overexpressed in human prostate cancers as compared with benign prostate tissues. Metastasis-derived canine prostate carcinoma cell lines overexpress EphA2 and may provide pre-clinical models to further evaluate the role of EphA2 in prostate carcinogenesis. Further investigations are needed to determine the utility of EphA2 as a tumor marker and a novel target in human prostate cancer.

Animals↗
PubMed1999

E-cadherin regulates the function of the EphA2 receptor tyrosine kinase.

EphA2 is a member of the Eph family of receptor tyrosine kinases, which are increasingly understood to play critical roles in disease and development. We report here the regulation of EphA2 by E-cadherin. In nonneoplastic epithelia, EphA2 was tyrosine-phosphorylated and localized to sites of cell-cell contact. These properties required the proper expression and functioning of E-cadherin. In breast cancer cells that lack E-cadherin, the phosphotyrosine content of EphA2 was decreased, and EphA2 was redistributed into membrane ruffles. Expression of E-cadherin in metastatic cells restored a more normal pattern of EphA2 phosphorylation and localization. Activation of EphA2, either by E-cadherin expression or antibody-mediated aggregation, decreased cell-extracellular matrix adhesion and cell growth. Altogether, this demonstrates that EphA2 function is dependent on E-cadherin and suggests that loss of E-cadherin function may alter neoplastic cell growth and adhesion via effects on EphA2.

Breast Neoplasms↗
PubMed1985

An analytical study of Doppler ultrasound systems.

The past theoretical contributions in Doppler ultrasonic imaging have borrowed heavily from the electromagnetic case. In these contributions, most points of departure between the ultrasonic and electromagnetic cases were taken care of by heuristic incorporation of factors in the derived formulas. A theory is presented that is more complete in the sense that it specifically accounts for the diffracted fields of the transducer aperture (assumed to be a source of a Gaussian focussed beam), the interaction of these fields with the scattering sites, and the interaction of the transducer aperture with the back scattered fields. The theoretical formulation was used to perform a series of computer simulation studies on Doppler ultrasound. The control afforded by the theory over different parameters of the system has allowed us to study the effect of the different signal bandwidths, tissue attenuation constants, and the role of transducer design in the ultrasound Doppler systems.

Blood↗
PubMed1978

[Aneurysm of Valsalva's sinus, apropos of 7 surgical cases[].

The authors describe 7 cases of rupture of the Valsalva sinus. Until rupture the aneurysm is silent. Aortic insufficiency and left to right shunt are major components of this syndrome. Surgical treatment under extra-corporal circulation needs aortotomy and an approach of the ruptured extremity to close the defect and maintaining the integrity of the valvular structures.

Adolescent↗
PubMed1977

[Surgery of aneurysm of the thoracic aorta. Operative results in 47 cases (author's transl)].

The authors report personal experience of surgical treatment of 47 aneurysms of the thoracic aorta, showing that the symptoms, the etiology, the treatment and the prognosis are variable depending on the site of the aneurysm. One may note regression of syphilis as a cause and an increase in the number of degenerative and traumatic aneurysms. In aneurysms of the ascending aorta, total replacement of the ascending aorta with reimplantation of the coronary arteries, according to a simplified technic, seems to give the best immediate and long term results.

Adult↗