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Biomedical subjects

A English

Publications and source records attributed to A English.

36 records · Page 2Linked to original sources
PubMed1995

Guidelines for adolescent health research: a position paper of the society for adolescent medicine.

Their ambiguous legal and ethical status has become a barrier to adolescents' appropriate involvement in research from which they may benefit and which is needed to improve adolescent health care and to inform health policy. Involvement of adolescents in research should be based on a scientific and empathetic understanding of their developing capabilities and a careful assessment of risks and benefits. The important role of parents and communities as protectors of adolescents should be respected and enhanced as we acknowledge and respect developing adolescent autonomy. These guidelines provide a framework to interpret the federal regulations for protection of human subjects in light of the unique legal, ethical, developmental, contextual, and racial issues that affect adolescents. The guidelines are designed to protect individual adolescent research subjects and to facilitate important youth research that would promote the health of adolescents.

Adolescent↗
PubMed1992

Expression of a lactogen-dependent insulin-like growth factor-binding protein in cultured mouse mammary epithelial cells.

The ability of normal mouse mammary epithelial cells (MECs) to express insulin-like growth factor-binding proteins (IGFBPs) was examined. MECs were isolated from day 11 pregnant mice and cultured on floating collagen gels in serum-free basal medium. After 24 h, the medium was replaced with fresh medium with/or without mouse PRL (mPRL), mouse placental lactogen-I (mPL-I), mPL-II, mouse GH (mGH), IGF-I, and IGF-II, either alone or in combinations. The MECs were cultured for an additional 5 days before collection of conditioned medium (CM). The relative amount of IGFBPs present in the CM was determined by Western ligand blotting, and alpha-lactalbumin content was determined with a specific RIA. The CM of the MECs contained two IGFBPs, with approximate mol wt of 29K and 40-45K. The 40-45K IGFBP appears to be the mouse equivalent of IGFBP-3, but the identity of the 29K IGFBP is not presently known. The 29K IGFBP was not N-glycosylated and did not cross-react with antiserum to rodent IGFBP-2 or human IGFBP-1. Basal IGFBP expression was very low, but the addition of mPL-I, or mPL-II stimulated a marked increase in the amount of 29K IGFBP that was released into the CM and a lesser increase in the release of IGFBP-3. This increase in the release of 29K IGFBP was dose dependent, with increases found at concentrations as low as 1 ng/ml lactogen. mGH also stimulated the release of 29K IGFBP, but was less potent than any of the three lactogens. Treatment of MECs with either IGF-I or IGF-II increased the amount of both the 29K IGFBP and IGFBP-3 in the CM, with relative potencies similar to those of the lactogenic hormones. However, when either IGF-I or IGF-II was added together with one of the lactogenic hormones, the release of 29K IGFBP was increased in an additive manner. While the IGFs acted additively with the lactogenic hormones on the expression of 29K IGFBP, they did not stimulate alpha-lactalbumin production by the MECs or act to enhance the effects of the lactogenic hormones in stimulating alpha-lactalbumin production. This study demonstrates that IGFBPs are expressed in normal mouse MECs, and the release of these IGFBPs into the CM is hormonally regulated by both lactogenic hormones and IGFs.

Animals↗
PubMed1991

Runaway and street youth at risk for HIV infection: legal and ethical issues in access to care.

Significant numbers of runaway and street youth are at risk for human immunodeficiency virus (HIV) infection. These youth are physically, socially, and psychologically vulnerable and need access to health care and related services. Legal and ethical concerns of consent and confidentiality may limit their access, although in many states the law allows some minors to consent to HIV testing and treatment and protects confidentiality of HIV-related information. Appropriate pretest and posttest counseling and follow-up for youth at risk of infection are essential. Limited access to HIV treatment for youth testing positive raises serious ethical concerns. Access to comprehensive treatment is currently limited by lack of adequate financing, despite a patchwork of numerous public funding sources providing some coverage for treatment of HIV and acquired immunodeficiency syndrome (AIDS). Research studies and clinical trials are critical elements in the planning and delivery of HIV-related services to adolescents, but require consideration of special ethical and legal concerns.

Adolescent↗
PubMed1991

Mandatory parental involvement/judicial bypass laws: do they promote adolescents' health?

Laws mandating parental involvement in the abortion decisions of pregnant adolescents exist in contrast to "medical emancipation" laws permitting competent minors to consent to their own care. Mandatory parental involvement laws have been the subject of extensive litigation. The Constitution of the United States requires states mandating parental consent or notification to offer the option of a "judicial bypass." In court proceedings, mature minors must be permitted to make their own decisions. Parental involvement/judicial bypass laws, when implemented, have failed to promote family consultation and have had adverse consequences for the pregnant adolescents they affect. States are permitted but not required by the federal Constitution to enact parental involvement/judicial bypass laws. Courts have prevented some of these laws from taking effect based on privacy guarantees in state constitutions. A few states have enacted alternative laws to ensure careful decision making and appropriate family or adult guidance and support.

Abortion, Legal↗
PubMed1991

Overcoming Obstacles to Adolescent Care: Legal Issues.

Although the complex patchwork of laws governing adolescent health care remains imperfect and continues to present obstacles for some adolescents seeking care, the recent trend in the law represents a move toward a beneficial accommodation of the interest of adolescents, their parents, and the state.

Journal Article↗
PubMed1990

Treating adolescents. Legal and ethical considerations.

Treating adolescents in the health care system raises significant legal and ethical issues related to consent for treatment, confidentiality of communications and records, and payment for care. The law provides many opportunities for adolescents to consent to their own care and offers significant protections of confidentiality. Publicly funded programs provide access to free care for some adolescents, but financial considerations continue to limit access for many poor and low-income adolescents. In addition to legal concerns, serious ethical dilemmas arise, particularly with respect to treatment of special populations of adolescents. Resolution of the legal and ethical questions requires cooperation of professionals from many disciplines.

Adolescent↗
PubMed1988

Guidelines for the control of human immunodeficiency virus infection in adolescents.

Although adolescents account for only 0.4% of reported cases of the acquired immunodeficiency syndrome (AIDS) in the United States, they are sexually active and, therefore, at risk of acquiring human immunodeficiency virus (HIV) infection. To address issues of HIV control in adolescents, we developed guidelines that emphasize education and medical care and deemphasize antibody testing. For adolescents known to be infected with HIV, we recommend no restrictions on access to educational or treatment programs except when their health providers recommend such restrictions to protect them from exposure to opportunistic infections. For adolescents of unknown antibody status with a possible previous exposure to HIV, we recommend that as long as the incidence of HIV infection and clinical AIDS remains low, there should be no restrictions on residential placements and no routine antibody testing.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Transient resonance Raman spectroscopy shows unrelaxed heme following CO photodissociation from cytochrome-c peroxidase.

The 7 ns 436 nm pulses of an H2-shifted YAG laser have been used to photolyze the CO adduct of cytochrome-c peroxidase and produce the resonance Raman spectrum of the photoproduct. A 3 cm-1 downshift, relative to the spectrum of reduced enzyme, was observed for the porphyrin C-N breathing mode, v4. The downshift diminishes with decreasing CO /protein ratio, implying, in conjunction with a recent study of CO binding, that the unrelaxed heme is associated with adduct having a tilted, H-bonded FeCO unit. The downshift is eliminated when the phosphate buffer concentration is increased from 0.01 to 0.1 M. It is proposed that the heme relaxation under study involves a transition between two conformations, B and A, differing in the disposition of the distal residues, and having different v4 frequencies for unligated Fe(II) heme. Conformation B allows H-bonding to bound CO, and is favored at high CO and phosphate concentrations, while conformation A, which is unfavorable to CO H-bonding, is favored at low CO and phosphate concentrations. The recently reported absence of unrelaxed frequencies in the 7 ns photo-product of the CO adduct of horseradish peroxidase has been confirmed, and is attributed to lower stability for conformation B and a smaller A - B v4 difference.

Carbon Monoxide↗
PubMed1986

Raman and infrared spectra of cytochrome c peroxidase-carbon monoxide adducts in alternative conformational states.

Resonance Raman (RR) spectra are reported for CO-bound cytochrome c peroxidase (CCP). At low pH, two forms are observed: form II, with nu Fe-C = 530 cm-1 and delta FeCO = 585 cm-1, and form I, with nu Fe-C = 495 cm-1 and no detectable delta FeCO. They appear to have coincident nu CO infrared bands, at 1922 cm-1. These low-pH forms, similar to those observed for horseradish peroxidase (HRP), are attributed to tilted, H-bonded CO and perpendicular CO, respectively. The frequencies differ between the two proteins, a weaker H bond to CO being indicated for CCP. As with HRP, the equilibrium between forms I and II is shifted toward the latter at increasing CO concentrations, suggesting that secondary binding of CO perturbs the distal residues. At high pH [8.4, tris(hydroxymethyl)aminomethane buffer] the form II fraction converts to another form, II', with nu FeC = 503 cm-1, delta FeCO = 575 cm-1, and nu CO = 1948 cm-1; a tilted, non-H-bonded geometry is suggested. If phosphate buffer is used, however, form II (H bonded) persists at pH 8.4. This result establishes a role for phosphate in stabilizing the H-bonded form of the enzyme; it is suggested that phosphate binds near the distal imidazole and substantially increases its pKa. The conformational state is also influenced by aging. Fresh protein contains purely high spin FeIII heme, as monitored by the high-frequency RR spectrum, and yields form II almost exclusively at elevated CO concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Carbon Monoxide↗
PubMed1978

Intellectual impairment in chronic renal failure.

In a dialysis centre with a high tap water aluminium content and a known high incidence of dialysis encephalopathy, 29 patients undertaking regular home dialysis, without clinical evidence of encephalopathy, were studied with a battery of psychological tests that have proved useful in detecting early organic intellectual deterioration in other conditions. Full-scale intelligence quotient, as measured by the Wechsler Adult Intelligence Scale, did not differ significantly from that of the normal population, but the patients showed significant deficiencies in three tests of performance--namely, digit symbol, block design, and picture arrangement. The ability to acquire new information in relation to performance was impaired and the abnormality increased with time on dialysis. Such tests should be useful in early detection of dialysis dementia at a reversible stage.

Adolescent↗