A cross-country qualitative study on contraceptive method mix: contraceptive decisionmaking among youth.

Background: Youth ages 15 to 24, who comprise a large portion of sub-Saharan Africa, face a higher burden of unmet contraceptive need than adults. Despite increased international and national commitments to improving young people's access to contraception, significant barriers impede their access to a full range of methods. To further explore these barriers among youth in Kenya, Nigeria, and Uganda, we conducted a qualitative study to capture the challenges that affect contraceptive method decisionmaking and complicate youth access to the full method mix.

Infant attention to same- and other-race faces.

We recorded visual attention to same- and other-race faces in Hispanic and White 11-month-old infants, an age at which face processing is presumably biased by an own-race recognition advantage. Infants viewed pairs of faces differing in race or ethnicity as their eye movements were recorded. We discovered consistently greater attention to Black over Hispanic faces, to Black faces over White faces, and to Hispanic over White faces.

Determinants of growth-promoting activity reside in the A-domain of insulin-like growth factor I.

A two-chain, disulfide linked, insulin-like compound embodying the A-domain of insulin-like growth factor I (IGF-I) and the B-chain of insulin has been synthesized and characterized with respect to insulin-like biological activity and growth-promoting potency. The compound displays a potency of ca. 41% relative to insulin in assays for insulin-like activity (e.

Possible involvement of the A20-A21 peptide bond in the expression of the biological activity of insulin. 3. [21-Desasparagine,20-cysteine ethylamide-A]insulin and [21-desasparagine,20-cysteine 2,2,2-trifluoroethylamide-A]insulin.

We have synthesized [21-desasparagine,20-cysteine ethylamide-A]insulin and [21-desasparagine,20-cysteine 2,2,2-trifluoroethylamide-A]insulin, which differ from natural insulin in that the C-terminal amino residue of the A chain, asparagine, has been removed and the resulting free carboxyl group of the A20 cysteine residue has been converted to an ethylamide and a trifluoroethylamide group, respectively. [21-Desasparagine,20-cysteine ethylamide-A]insulin displayed equivalent potency in receptor binding and biological activity, ca. 12% and ca.

Possible involvement of the A20-A21 peptide bond in the expression of the biological activity of insulin. 2. [21-Asparagine diethylamide-A]insulin.

We have synthesized [21-asparagine diethylamide-A]insulin, which differs from the parent molecule in that the free carboxyl group of the C-terminal amino acid residue, asparagine, of the A chain moiety has been converted to a diethylamide group. The analogue displays equivalent potency in receptor binding and biological activity, 48% and 56%, respectively, relative to bovine insulin. In contrast, we have reported previously [Burke, G.

Possible involvement of the A20-A21 peptide bond in the expression of the biological activity of insulin. 1. [21-Desasparagine,20-cysteinamide-A]insulin and [21-desasparagine,20-cysteine isopropylamide-A]insulin.

The C-terminal region of the A chain of insulin has been shown to play a significant role in the expression of the biological activity of the hormone. To further delineate the contribution of this segment, we have synthesized [21-desasparagine,20-cysteinamide-A]insulin and [21-desasparagine,20-cysteine isopropylamide-A]insulin, in which the C-terminal amino acid residue of the A chain of insulin, asparagine, has been removed and the resulting free carboxyl group of the A20 cysteine residue has been converted to an amide and an isopropylamide, respectively. Both insulin analogues display biological activity, 14-15% for the unsubstituted amide analogue and 20-22% for the isopropylamide analogue, both relative to bovine insulin.

Effect of N-methylation of selected peptide bonds on the biological activity of insulin. [2-N-methylisoleucine-A]insulin and [3-N-methylvaline-A]insulin.

Hydrogen bonding involving peptide bonds of the backbone of the insulin molecule may play an important role in insulin-receptor interaction. Our previous work suggested that the A2-A8 helical segment of the hormone molecule participates in this interaction. To investigate the possible involvement of peptide bonds of this segment in insulin-receptor interaction the [2-N-methylisoleucine-A]insulin and [3-N-methylvaline-A]insulin ([MeIle2-A]- and [MeVal3-A]insulins) were synthesized.

Interaction between the A2 and A19 amino acid residues is of critical importance for high biological activity in insulin: [19-leucine-A]insulin.

The replacement of tyrosine at position A19 by leucine in the insulin molecule led to an analogue, [19-leucine-A]insulin [( Leu19-A]insulin), displaying insignificant receptor binding affinity and in vitro biological activity less than 0.1 and 0.05%, respectively, compared to the natural hormone.

Critical role of the A2 amino acid residue in the biological activity of insulin: [2-glycine-A]- and [2-alanine-A]insulins.

We report the synthesis of [2-glycine-A]insulin ([ Gly2 -A]insulin) and [2-alanine-A]insulin ([ Ala2-A]insulin) in which the indicated amino acid has been substituted for isoleucine found in this position in the natural hormone. The circular dichroic (CD) spectra of the analogues were obtained, and their properties were examined in several biological assays. CD studies suggested that the analogues remain monomeric at concentrations at which insulin is partly or mostly dimeric.

An insulin analogue possessing higher in vitro biological activity than receptor binding affinity. [21-Proline-B]insulin.

To study the effect of an increase in the potential for beta-turn formation of the B20-B23 segment of the B-chain moiety on the biological behavior of insulin, the [21-proline-B]insulin [( Pro21-B]insulin) was synthesized. The in vitro biological activity and the receptor binding affinity of this analogue were compared with that of insulin. In stimulating labeled glucose incorporation into lipids in rat fat cells, the analogue displayed 33.

Lithium-induced changes in plasma amino acid levels during treatment of affective disorders.

Plasma amino acid (AA) profiles were determined in patients with bipolar affective disorders before and during treatment with lithium (Li) carbonate. After 90 days of Li intake, there were moderately (20-60%) but significantly decreased plasma levels of isoleucine, leucine, and valine. After 150 days of Li intake, the plasma lysine was also significantly decreased (12%).

Elevation of erythrocyte glycine levels during lithium treatment of affective disorders.

An elevation of erythrocyte (RBC) glycine was observed in a group of patients with bipolar affective disorder who were being treated with lithium (Li) carbonate. A maximal increase of 90% or more was generally attained after about 100 days of Li intake and was maintained for 2 years or longer. After 3 or more years of Li therapy, the RBC glycine had often returned to the normal range.

[A2-Norleucine]insulin. An analog with unanticipated biological properties.

The simple replacement of the A2-isoleucine by norleucine in the insulin molecule gave an analog [A2-norleucine]insulin ([Nle A2]-insulin) which was found to possess insignificant receptor-binding affinity and in vitro biological activity, 0.6 and 0.9 percent, respectively, compared to the natural hormone.

Divergence of the in vitro biological activity and receptor binding affinity of a synthetic insulin analogue, [21-asparaginamide-A]insulin.

The [21-asparaginamide-A]insulin ([Asn-(NH2)21-A]insulin) was synthesized by the procedures developed in this laboratory to investigate the contribution of the C-terminal residue, asparagine, of the A chain to the biological activity and receptor binding affinity of insulin. Its secondary structure was investigated by circular dichroism studies. The biological behavior of this analogue was compared with that of insulin in in vitro and in vivo tests and in receptor binding assays.

Determination of erythrocyte amino acids by gas chromatography.

Erythrocyte amino acid levels were determined, by gas chromatography, in a group of 34 normal human adults. No significant sex or age correlations were noted. A method for the quantitative gas chromatographic analysis of free amino acids in erythrocytes is described.

Amino acids in bipolar affective disorders: increased glycine levels in erythrocytes.

The authors measured the concentrations of 20 amino acids in the erythrocytes and plasma of 13 female bipolar patients and 10 female normal controls. The concentration of glycine in the erythrocyte was significantly elevated in the patient group. No differences were present in the plasma.

Dopamine-beta-hydroxylase: evidence for increased activity in sympathetic neurons during psychotic states.

Tritiated dopamine was infused into psychiatric patients during acute psychotic episodes and in remission. An index of the activity of dopamine-beta-hydroxylase of salivary gland sympathetic neurons was determined by measuring the distribution of tritiated metabolites in salivary fluid. Increased synthesis of norepinephrine occurred in acute schizophrenia and in the manic state of manic-depressive psychosis but not in the depressed phase.