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Biomedical subjects

A Bodnar

Publications and source records attributed to A Bodnar.

9 recordsLinked to original sources
PubMed1999

Human endothelial cell life extension by telomerase expression.

Normal human endothelial cells, like other somatic cells in culture, divide a limited number of times before entering a nondividing state called replicative senescence. Expression of the catalytic component of human telomerase, human telomerase reverse transcriptase (hTERT), extends the life span of human fibroblasts and retinal pigment epithelial cells beyond senescence without causing neoplastic transformation (Bodnar, A. G., Ouellette, M., Frolkis, M., Holt, S. E., Chiu, C. P., Morin, G. B., Harley, C. B., Shay, J. W., Lichtsteiner, S., and Wright, W. E. (1998) Science 279, 349-352; Jiang, X., Jimenez, G., Chang, E., Frolkis, M., Kusler, B., Sage, M., Beeche, M., Bodnar, A., Wahl, G., Tlsty, T., and Chiu, C.-P. (1999) Nat. Genet. 21, 111-114). Here, we show that both human large vessel and microvascular endothelial cells also bypass replicative senescence after introduction of hTERT. For the first time, we report that hTERT expression in these life-extended vascular cells does not affect their differentiated and functional phenotype and that these cells maintain their angiogenic potential in vitro. Furthermore, hTERT(+) microvascular endothelial cells have normal karyotype, and hTERT(+) endothelial cell strains do not exhibit a transformed phenotype. Relative to parental cells at senescence, hTERT-expressing endothelial cells exhibit resistance to induction of apoptosis by a variety of different conditions. Such characteristics are highly desirable for designing vascular transplantation and gene therapy delivery systems in vivo.

Apoptosis↗
PubMed1997

Subacute sclerosing panencephalitis manifesting as viral retinitis: clinical and histopathologic findings.

PURPOSE AND METHODS: To describe the clinical and histopathologic features of a patient with viral retinitis secondary to subacute sclerosing panencephalitis. RESULTS: The patient was a human immunodeficiency virus-negative intravenous drug abuser with an acute retinitis that later progressed to encephalitis despite aggressive treatment for possible viral, protozoal, bacterial, and rickettsial infections. The patient had many of the characteristic findings of subacute sclerosing panencephalitis, including a history of measles in early childhood, myoclonus, periodic complexes on electroencephalographic testing, persistently elevated serum and cerebrospinal fluid antimeasles immunoglobulin G (IgG) titers, and a cerebrospinal fluid oligoclonal IgG gammopathy. Ultrastructural examination demonstrated numerous filamentous microtubular intranuclear viral inclusions in the nuclear layers of the retina consistent with the measles virus. This case is unusual in that our patient developed subacute sclerosing panencephalitis later in life and because there was an 8-year period between presumed viral infections in the two eyes. CONCLUSIONS: An acute retinitis in an intravenous drug abuser is not always caused by human immunodeficiency virus-related infections; not all viral retinitis responds to therapy; and mortality as well as the usual morbidity may be associated with viral retinitis. One might consider the diagnosis of subacute sclerosing panencephalitis in a young person with an acute retinitis with little or no vitreal inflammation and lack of response to anticytomegalovirus and antitoxoplasmosis therapy.

Adult↗
PubMed1997

Gradual phenotypic conversion associated with immortalization of cultured human mammary epithelial cells.

Examination of the process of immortal transformation in early passages of two human mammary epithelial cell (HMEC) lines suggests the involvement of an epigenetic step. These lines, 184A1 and 184B5, arose after in vitro exposure of finite lifespan 184 HMEC to a chemical carcinogen, and both are clonally derived. Although early-passage mass cultures of 184A1 and 184B5 maintained continuous slow growth, most individual cells lost proliferative ability. Uniform good growth did not occur until 20-30 passages after the lines first appeared. Early-passage cultures expressed little or no telomerase activity and telomeres continued to shorten with increasing passage. Telomerase activity was first detected when the telomeres became critically short, and activity levels gradually increased thereafter. Early-passage cultures had little or no ability to maintain growth in transforming growth factor-beta (TGFbeta); however, both mass cultures and clonal isolates showed a very gradual increase in the number of cells displaying progressively increased ability to maintain growth in TGFbeta. A strong correlation between capacity to maintain growth in the presence of TGFbeta and expression of telomerase activity was observed. We have used the term "conversion" to describe this process of gradual acquisition of increased growth capacity in the absence or presence of TGFbeta and reactivation of telomerase. We speculate that the development of extremely short telomeres may result in gradual, epigenetic-based changes in gene expression. Understanding the underlying mechanisms of HMEC conversion in vitro may provide new insight into the process of carcinogenic progression in vivo and offer novel modes for therapeutic intervention.

Adult↗
PubMed1996

[Femoropatellar pain syndrome--conservative therapeutic possibilities].

Patello-femoral knee pain is a frequent problem the general practitioners, rheumatologists and orthopedists are confronted with. Very often, no exact structural diagnosis can be made. Studies on the natural history of PFPS are lacking. Nevertheless, conservative treatment has been successful in most of the cases. In this respect, management being pertinent to each patient and problem is important. Four categories of frequently affected patients are discussed in this article: young people in their adolescence, well trained athletes, athletes at the end of their career and patients in the 'second half' of their life. The stages of soft-tissue healing in the course of treatment over a long time are of importance. In the sense of a secondary prevention, the intrinsic and extrinsic risk factors have to be considered as well. The taping technique offers an easy and effective treatment method. It usually pulls the patella medially, thereby 'unloading' the joint and the surrounding soft tissues. In an early stage, this results in an analgesic effect and allows an early functional load. In a later stage, the patella tape helps to prevent reinjury.

Adolescent↗
PubMed1981

Subglottic stenosis in newborn intensive care unit graduates.

Five infants with postintubation subglottic stenosis were identified among 64 intubated patients in a follow-up clinic. The presence of laryngeal lesions was not suspected until three weeks to three months after discharge from their initial hospitalization. The onset of stridor, often precipitated by respiratory illness, led to the diagnosis, which in one case was delayed for as long as three months. No correlation was found between the presence of the severity of laryngeal pathology and the gestational age of the infants or the duration of intubation in this study. In spite of the precautions taken for the intubation of neonates requiring assisted ventilation, subglottic stenosis may develop in these infants and should always be considered in newborn intensive care unit graduates when they manifest refractory or recurrent respiratory obstruction in the first year of life. Routine follow-up of all intubated neonates to detect subglottic stenosis is recommended.

Critical Care↗
PubMedDate not supplied

The visually inattentive preterm infant.

A retrospective study was made of 16 premature infants who were visually inattentive despite normal eye findings and a lack of factors predisposing them to cerebral blindness. A comparison of this study group with other premature infants who were visually attentive revealed a much greater incidence of upper motor neuron disease and mental retardation in the study infants.

Female↗