Evaluation of a Home Visiting and Befriending Scheme for Young Mothers: Newpin

Befriending schemes to support families with young children are now widespread in the United Kingdom. One such scheme, Newpin, which aims to prevent child abuse is described. Evaluation compared those recruited to befriend as well as those befriended. Assessments at baseline and 6 months' follow-up comprised interviews with mothers, developmental assessments of the children and observation of mother–child interaction using video tapes. All assessments were conducted in the home and similar measures were applied to a control sample in an area where a Newpin scheme was planned. Newpin recruits, whether befrienders or befriended had high rates of adverse early experiences, but depression was more common amongst those referred for befriending. Approximately a third did not sustain involvement in the scheme, but those that did were more likely to have had training as volunteers and mental health problems of more than 2 years' duration.

Molecular-weight dependence of the glass transition temperature of freely-standing poly(methyl methacrylate) films

We have used transmission ellipsometry to measure the glass transition temperature, T(g), of freely-standing films of atactic and syndiotactic poly(methyl methacrylate) (PMMA). We have prepared films with different molecular weights, MW, (159 x 10(3) < M (w) < 1.3 x 10(6)) and film thicknesses, h, ( 30 nm < h < 200 nm). For the high-MW ( M (w) > 509 x 10(3)) atactic PMMA films, we find that T(g) decreases linearly with decreasing h, which is qualitatively similar to previous results obtained for high-MW freely-standing polystyrene (PS) films. However, the overall magnitude of the T(g) reduction is much less (by roughly a factor of three) for the high-MW freely-standing PMMA films than for freely-standing PS films of comparable MW and h. The observed differences between the freely-standing PMMA and PS film data suggest that differences in chemical structure determine the magnitude of the T(g) reduction and we discuss the possible origins of these differences. Our analysis of the MW-dependence of the T(g) reductions suggests that the mechanism responsible for the MW-dependent T(g) reductions observed in the high-MW freely-standing films is different than that responsible for the MW-independent T(g) reductions observed in the low-MW freely-standing and supported films.

Expression of human chorionic gonadotropin uniformly labeled with NMR isotopes in Chinese hamster ovary cells: an advance toward rapid determination of glycoprotein structures

Most secreted eukaryotic proteins are modified by glycosylation, and it has been difficult to solve their structures by crystallographic or NMR techniques because of problems posed by the presence of the carbohydrate. The structure of a chemically deglycosylated form of the human pregnancy hormone, human chorionic gonadotropin (hCG), has been solved by crystallographic methods. Since chemical deglycosylation may have induced changes in the structure, and since it is known that deglycosylated hCG is biologically inactive, the crystallographic structure confirmation by NMR techniques. Also, it has not been possible to determine the structures of the isolated subunits, nor the nature of interactions between the carbohydrate side chains and the protein backbone by crystallographic methods. Structural information via NMR techniques can be obtained from proteins in solution if they can be uniformly labeled with 13C and 15N isotopes. We report the first such uniform labeling of a glycoprotein using a universal 13C- and 15N-labeling medium to express 13C, 15N-labeled hCG, suitable for solving the structure in solution of the native, biologically active form of hCG as well as that of its free subunits. The 13C, 15N-labeled recombinant hCG and its separated subunits are shown to be nearly identical to urinary hCG reference preparations on the basis of protein chemical studies, immunochemistry, biological activity, and the capability of isolated hormone subunits to recombine to form biologically active hormone. Mass spectrometric analysis and preliminary NMR studies indicate that the isotopic labeling is uniform and greater than 90% after only two growth passages in the labeling media. One unexpected finding during subunit purification was that lyophilization of glycoproteins from trifluoroacetic acid HPLC buffers may result in the loss of a significant portion of sialic acid.

Isolation and characterization of human pituitary chorionic gonadotropin

Human CG (hCG) is the hormone associated with the maintenance of pregnancy. Although three related glycoprotein hormones, LH, hFSH, and hTSH, are secreted by the pituitary, HCG is the only one of this family of glycoprotein hormones that is produced by the placenta in primates to maintain the steroid hormone secretions of the corpus luteum. Although hCG is not considered to be a pituitary hormone, hCG-like immunoreactive materials have been reported in pituitary tissue, blood, and urine from healthy nonpregnant individuals for 2 decades, but it was never isolated. We now report the purification and characterization of pituitary hCG from acetone-preserved human pituitary glands. After gell permeation chromatography, the fractions containing hCG molecules were pooled and purified by immunoaffinity chromatography using antibodies to the COOH-terminal region of hCGbeta. Amino acid analyses, amino-terminal sequence analyses, as well as mass spectrometric studies gave similar results for both pituitary hCG and hCG purified from the urine of pregnant women. Analyses for sulfate and sialic acid contents demonstrated that pituitary hCG contained both sulfate and sialic acid. In vitro biological activity of pituitary hCG indicated that it was 50% as active as hCG purified from the urine of pregnant women in cAMP assays.

Expression and DNA-binding properties of the 14K carboxyl terminal fragment of Escherichia coli DNA topoisomerase I

DNA sequence coding for the last 121 amino acids of Escherichia coli topoisomerase I was synthesized by PCR and cloned into a plasmid under the control of the T7 promoter. Induction of T7 RNA polymerase in E. coli carrying the plasmid clone resulted in over-expression of this C-terminal domain fragment previously shown to confer higher DNA binding affinity to the enzyme. Purification to homogeneity was achieved by phosphocellulose and single-stranded DNA agaraose chromatography. Direct interaction between this 14K domain and poly(dA) was demonstrated by UV spectroscopy. Noncovalent complexes formed between this fragment and oligo(dT) 8 and oligo(dT) 16 can also be trapped by photo-crosslinking.

The impact of maternal depression in young children

An urban working class sample of depressed mothers with two-yr-old children was compared with a control group of non-depressed mothers using maternal interviews, home observation of mother/child interaction, and developmental assessment of the children. Measures were repeated after six months. Children of depressed mothers showed more emotional and behavioural disturbance and delay in expressive language development. Depressed mothers had more past and current adverse experiences, particularly in close relationships. In general depressed mothers were less responsive to their children and less able to sustain social interaction: their children were more often distressed, but there was a big variation in quality of mother/child interaction within the depressed group.