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Biomedical subjects

K Hein

Publications and source records attributed to K Hein.

At least 37 records · Page 2Linked to original sources
PubMed1991

Theophylline disposition in adolescents with asthma.

Adolescents frequently require medication for acute and chronic illnesses. A proper dosage schedule is needed to achieve efficacy without toxicity during adolescence when there are marked changes in body size and organ function. Theophylline disposition was studied in 70 asthmatic adolescents, ages 8-18 years, to determine if pubertal changes in body size, composition, and organ function are associated with changes in drug disposition. Forty-eight youngsters were studied as outpatients and 22 while hospitalized. Half-life (t1/2) was computed for all patients. Volume of distribution and clearance were determined for inpatients only. Chronological age and anthropometric growth parameters were measured. Lean body mass (LBM) was derived from anthropometric measurements. Half-life was significantly correlated with developmental stage (Tanner r = 0.42, age r = 0.33, p less than 0.01), and body size (height r = 0.39, LBM r = 0.33, weight r = 0.33, p less than 0.01). LBM (kg/kg) was significantly correlated with volume of distribution (L/kg) (r = 0.59, p less than 0.01). Best-fits for t1/2 contained two variables: t1/2 = -4.57 + 1.31 (sex) + 0.0687 (height) (r = 0.48) and t1/2 = -3.54 + 1.32 (sex) + 0.0725 (LBM) (r = 0.43). Chronological age alone is not a useful basis for determining medication dosages due to the heterogeneity in rates of development and body size among adolescents. Half-life increases with increasing height or LBM. Although compliance is clearly an important factor in achieving optimal control of symptoms, this study demonstrates that dose adjustment during times of rapid growth during puberty is equally important.

Adolescent↗
PubMed1990

HIV infection and AIDS during adolescence.

It is clear from the evidence that a growing number of adolescents are acquiring HIV infection and developing AIDS. The impact this epidemic will have on all teenagers is overwhelming. Given the high prevalence of risk-related sexual behaviors, many adolescents are likely to become HIV infected, thus requiring extensive medical and psychosocial services. Other adolescents will lose a parent, relative, or friend to AIDS, and these adolescents will similarly require special services and psychological counseling. Thus, there is an immediate need for the development of methods for (1) providing all adolescents with age-appropriate and culturally relevant interventions for prevention and risk reduction, (2) identifying high-risk adolescents and triaging them to different levels of care and risk reduction counseling, and (3) providing ongoing medical and psychosocial treatments. Accessing adolescents at risk for HIV infection will require networking between the health care system and youth-serving and community-based agencies, particularly agencies servicing high-risk adolescents. We must begin addressing these needs now, in order to prevent further infection and to provide appropriate care for those adolescents who are or will become infected with HIV.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Model for the kinetics of imipramine and its metabolites in adolescents.

A kinetic model for imipramine (IMI) has been developed, based upon a study of 16 teenagers who received IMI 4-5 mg/kg/day for treatment of a major depressive disorder. Serial measurements of plasma concentrations of IMI, desmethylimipramine (DMI), 2-hydroxy-IMI, and 2-hydroxy-DMI were made. Mean residence times, volumes of distribution, clearances of IMI and DMI, and rate constants for formation and elimination of the hydroxy metabolites were determined from a multicompartment model fitted to the concentration-time data. Mean residence time for DMI was significantly longer than for IMI (47.1 +/- 21.2 vs. 13.4 +/- 4.8 h, p less than 0.001). A different volume of distribution for IMI and DMI was not supported by the data. Clearance of DMI was considerably slower than that of IMI (0.67 +/- 0.45 vs. 2.18 +/- 1.33 l(kg.h), p less than 0.001). A statistically significant increase in mean residence time with increasing age during adolescence was found (r = 0.57, p less than 0.05).

Adolescent↗
PubMed1990

Acquired Immunodeficiency Syndrome (AIDS) in Adolescents.

This chapter reviews the epidemiology of acquired immunodeficiency syndrome (AIDS) and human immunodeficiency virus (HIV) infection among adolescents, presents a theoretical model for defining risk, and reviews factors that put adolescents at risk for HIV infection. Issues pertaining to risk assessment, HIV counseling and testing, and approaches to care for HIV-infected teens are discussed. Finally, practical strategies for HIV prevention and risk reduction are provided.

Journal Article↗
PubMed1990

Lysosomal beta-galactosidase from rat liver: purification, molecular forms and association with neuraminidase.

A simple procedure for purification of lysosomal beta-galactosidase from rat liver was developed. The association state of the purified enzyme has been found to depend on pH and ionic strength. Under acidic conditions and at high ionic strength, the enzyme is aggregated into a high molecular weight complex having a molecular weight of about 700,000. Increasing pH and lowering the ionic strength favour the disaggregation of the complex to an enzyme species whose molecular weight is 160,000. These two enzyme forms differ markedly in their hydrophobicity, but no significant differences in kinetic properties have been found. Galactose and galactose-1-amine were competitive inhibitors of beta-galactosidase. Neuraminidase is associated with the multimeric form of beta-galactosidase, whereas the low molecular weight form did not show any neuraminidase activity. The stability of neuraminidase has been found increase in the presence of magnesium ions.

Animals↗
PubMed1990

[Dermatophyte infections caused by Microsporum canis and Microsporum audouinii in the Greifswald area].

Report of serial diseases of dermatophytoses caused by M. canis (5 patients) and M. audouinii (9 patients). Two cats and a dog were the infective source of M. canis-infection. M. audouinii-infection was stated in a children ward; here the infective source had not been detected. Remarkable are the identical morphological lesions of tinea capitis resp. corporis and the affections of adults in the two groups of patients. Griseofulvin therapy and additional veterinary hygienical treatment in case of M. canis-infection the two endemis were dissipated in few weeks.

Adult↗
PubMed1989

Acquired immunodeficiency syndrome among adolescents. Case surveillance profiles in New York City and the rest of the United States.

Adolescents engaging in certain sexual or drug-related behavior are at risk of contracting the human immunodeficiency virus infection in endemic locales. Local and national surveillance data were analyzed to determine the characteristics of the acquired immunodeficiency syndrome (AIDS) epidemic on adolescents. Of the 605 cases of AIDS in people aged 13 to 21 years reported through 1987, 518 were males (83 from New York City [NYC], NY), and 87 were females (28 from NYC). Over half of all adolescent males with AIDS reported homosexual contact. Transfusion/blood product-related human immunodeficiency virus acquisitions (especially in males with hemophilia) represented 11% of adolescent cases from NYC (1% of NYC adults) and 22% of adolescent cases in the United States (US) outside of NYC (4% of adults in the US). Intravenous drug use was more frequently reported among adolescents with AIDS from NYC (23%) than among adolescents outside NYC (14%). In females, heterosexual transmission accounts for about half of all adolescent AIDS cases and 29% of all adult cases. Age-appropriate services and behavioral interventions are urgently needed for high-risk adolescents.

Acquired Immunodeficiency Syndrome↗