PubMed Health⌕ Search

Biomedical subjects

C Croft

Publications and source records attributed to C Croft.

15 recordsLinked to original sources
PubMed2003

Bone morphogenetic protein 9: a potent modulator of cartilage development in vitro.

Few publications describe the activity of bone morphogenetic protein-9 (BMP-9), but the consensus of these largely in vivo studies is that while BMP-9 can induce ectopic bone formation at relatively large concentrations, it is primarily active in non-skeletal locations--including the liver, nervous system and marrow. To study the effects of BMP-9 on chondrogenesis in a well-defined environment, calf articular chondrocytes were seeded onto biodegradable PGA scaffolds. The resulting cell-polymer constructs were cultured in either control medium or medium supplemented with 1, 10, 50 or 100 ng/ml of BMP-9. After 4 weeks of in vitro culture, all concentrations of BMP-9 increased the total mass of the constructs, and the amounts of collagen, glycosaminoglycans (GAG) and cells per construct. On a mass percentage basis, BMP-9 tended to increase GAG, to decrease the relative amount of collagen and had little effect on the relative amount of cells. BMP-9 elicited qualitatively similar responses as BMP-2, -12 and -13. However, in contrast to BMP-12 and -13, BMP-9 (at concentrations > or = 10 ng/ml) induced hypertrophic chondrocyte formation and was the only BMP tested to induce mineralization. Taken together, these data suggest that BMP-9 is a potent modulator of cartilage development in vitro.

Alkaline Phosphatase↗
PubMed2001

Longitudinal change in parenting associated with developmental delay and catch-up.

The current study examined the predictors of parent-child relationship quality and developmental change in a sample of children adopted into the U.K. following severe early privation, and in a comparison sample of nondeprived, within-country adoptees. One hundred and fifty-eight children adopted from Romania and 52 U.K. adoptees were assessed at age 6 years; longitudinal data (age 4 and 6 years) were available on the 110 Romanian adoptees placed into U.K. homes before 24 months of age and all U.K. adoptees. Ratings of parent-child positivity and negativity during a semistructured interaction task were obtained from coders who were blind to the child's background. Results indicated that adoptive parent-child relationship quality was related to duration of deprivation and that cognitive/developmental delay mediated this association. The magnitude of this effect was modest and diminished over time. Longitudinal analyses revealed that positive change in parent-child relationship quality was most marked among children who exhibited cognitive catch-up between assessments. The direction of effects appeared to be primarily child to parent. The findings underscore the need for further research on the long-term impact of early experiences on psychosocial development.

Adoption↗
PubMed2000

The contributions of behavioural genetic studies to attachment theory.

This review considers the ways in which the methods and theories of behavioural genetics and attachment theory are mutually informative. Four issues are discussed. First, the benefits of the adoptive and twin research designs for testing attachment theory proposals are examined. Second, the ways in which attachment research may elucidate the behavioural genetic concepts of 'shared' and 'non-shared' environment are assessed. Third, the methods use to clarify the role of child effects on child-parent attachment quality are addressed. Finally, the limitations and data analytic considerations of synthesizing behavioural genetic and attachment research are outlined.

Adoption↗
PubMed1988

Effect of hyaluronidase on mortality and morbidity in patients with early peaking of plasma creatine kinase MB and non-transmural ischaemia. Multicentre investigation for the limitation of infarct size (MILIS).

A multicentred, randomised, blind study was started in 1978 to compare propranolol or hyaluronidase with placebo in patients with acute myocardial infarction admitted within 18 hours of onset of symptoms. Patients were randomised to group A and received hyaluronidase, propranolol, or placebo, or, if propranolol was contraindicated, to group B and received hyaluronidase or placebo. Hyaluronidase (500 U/kg given every six hours for 48 hours) had no effect on mortality or infarct size in the overall population. Because spontaneous reperfusion was more common in patients with early peaking of plasma creatine kinase MB or non-transmural electrocardiographic changes or both, the results were reanalysed for two subgroups: those in whom plasma creatine kinase peaked less than 15 hours after the onset of symptoms (early peak, n = 184) and those with a peak greater than 15 h after the onset of symptoms (late peak, n = 546). The distribution of time to peak activity of creatine kinase MB was similar in the hyaluronidase and placebo groups. In the early peak patients who were given hyaluronidase (groups A and B) total mortality and cardiac-specific four year mortality were significantly lower. This was most pronounced in group B in which the total mortality was 45% and cardiovascular mortality was 47% less than in the placebo group. Similarly, mortality from cardiovascular disease in patients (groups A and B) with nontransmural ischaemia (ST-T changes) given hyaluronidase was significantly lower, with group B showing a 50% reduction. In the subsets of patients with late peaking of creatine kinase MB or those presenting with transmural electrocardiographic changes there was no difference in total mortality or deaths from cardiac disease between those given hyaluronidase and those given placebo. Hyaluronidase was associated with improved survival in patients with early peaking of plasma creatine kinase MB, suggesting the possibility of salvage of myocardium in patients who have early spontaneous reperfusion and possibly after therapeutic reperfusion.

Clinical Trials as Topic↗
PubMed1986

The treatment of recurrent tonsillitis in adults.

A prospective study comparing surgical and antibiotic treatment for recurrent tonsillitis in adults suggests that, whilst tonsillectomy is very effective, adequate medical treatment provides an equally good alternative in the majority of patients.

Adolescent↗
PubMed1984

Effect of propranolol on myocardial-infarct size in a randomized blinded multicenter trial.

A multicenter randomized single-blind study was performed to evaluate the effects of propranolol administered during the evolution of myocardial infarction. Five centers enrolled a total of 269 patients, with 134 receiving propranolol and 135 placebo. Propranolol or placebo was given intravenously upon randomization (0.1 mg per kilogram of body weight) and then orally for nine days to keep the heart rate between 45 and 60 beats per minute. Less than 2 per cent of patients were treated within 4 hours after the onset of symptoms, but 50 per cent received therapy within 8 hours of onset of chest pain, and the remainder between 8 and 18 hours. The heart rates in the propranolol-treated group were significantly lower than those in the placebo group (P less than 0.001). Base-line characteristics, including the mean heart rate (79.6 vs. 81.3) and the left ventricular ejection fraction (49.0 vs. 49.5), were similar in the two groups. The primary end point evaluated--infarct size as estimated from plasma MB creatine kinase activity--was virtually identical in the two groups, averaging 13.3 and 13.6 gram-equivalents of MB creatine kinase per square meter of body-surface area. Peak plasma levels of the enzyme were also similar in the two groups. No significant difference was observed between the propranolol and placebo groups in the change in left ventricular ejection fraction, extent of area involved in pyrophosphate uptake, R-wave loss on electrocardiograms, or mortality (after three years). These results do not support the use of propranolol administered four or more hours after the onset of symptoms to limit infarct size.

Administration, Oral↗
PubMed1979

Pharyngeal hypoplasia in Treacher Collins syndrome.

Examination of 11 patients with Treacher Collins syndrome (TCS), with the use of multiple-view videofluoroscopy and nasopharyngoscopy of the pharynx, disclosed marked narrowing of the airway. In several patients, the pharynx was less than 1 cm in width at its most narrow point. It is thought that reduced airway in TCS may help to explain the frequent reports of neonatal death associated with the syndrome. Pharyngeal narrowing was found throghout the entire vertical height of the pharynx in all 11 patients. Pharyngeal hypoplasia is probably responsible for reported difficulties in intubating patients with TCS for endotracheal anesthesia and for respiratory complications after palatoplasty and pharyngoplasty. Pharyngeal hypoplasia is considered to be a primary feature of the syndrome and may aid in its diagnosis.

Adolescent↗