Evaluation of NaOH treatment of human dura mater implants to obviate Creutzfeldt-Jakob disease transmission.

One of the few disinfectants known to inactivate the causative agent of Creutzfeldt-Jakob Disease is NaOH. In this study, NaOH was evaluated as a possible routine treatment for human dura mater alloimplants. Use of high concentration NaOH (1 M) resulted in protein loss and macroscopic changes to the tissue. Lower concentrations (0.1 M), although exhibiting little direct detrimental effect, greatly increased the susceptibility of the tissue to collagenase digestion. The use of NaOH treated commercial or institutionally prepared human dura mater should be approached with caution.     

Pretreatment of bone with osteoclasts affects phenotypic expression of osteoblast-like cells.

Implant surface morphology regulates osteoblast phenotypic expression. Osteoblast sensitivity to non-biologic surfaces suggests that native bone surface features may also affect osteoblast response. To test this, MG63 osteoblast-like cells were grown for 7 days on bovine cortical bone wafers pretreated with rat bone marrow osteoclasts for 0, 10 or 20 days. Response to osteoclast-treated surfaces was compared to the response of MG63 cells to titanium surfaces with smooth and rough microtopographies. Cell number, differentiation (alkaline phosphatase activity and osteocalcin levels), and local factors (PGE(2) and TGF-beta1) were measured in confluent cultures. Compared to culture on plastic, cell number was reduced on all three types of bone wafers; this effect was dose-dependent with increasing resorption of the surface. Alkaline phosphatase specific activity was increased (P相似文献   

Source agreement in assessing youth stress and negative affectivity: New evidence for an old problem

The present study examined dichotomies potentially relevant to parentchild and interparent agreement in the assessment of internalizing problems in youngsters. Specifically, 98 children and their parents completed the Daily Life Stressors Scale or a variant to examine child ratings of daily stress, parent ratings of their children's daily stress, and parent predictions of how their children would self-rate their stress. In addition, a distinction was made between subscores of negative affectivity and stressful life events. Results indicated moderate parent-child and interparent agreement, with the latter somewhat more influenced by a negative affectivity-stressful events dichotomy. Parent-child agreement appeared more enhanced for items involving more parental contact. Implications of these data for future research are discussed.     

Primary care residents and the management of hypercholesterolemia

A survey of primary care residents' attitudes, beliefs, and knowledge and a medical record audit were used to assess barriers to appropriate detection, identification, and management of hypercholesterolemia. Previous studies have focused on either self-reports or audits alone. This study compares survey results to recorded clinical performance. Family practice and internal medicine residents were compared to determine if previous findings were specialty-specific. The results of the survey indicate that, even prior to the publication of the National Cholesterol Education Program, residents demonstrated positive attitudes and appropriate knowledge of risk levels, in contrast with previous reports on practicing physicians. The medical record audit, however, showed that residents were not providing care that approximated their own recommendations for hypercholesterolemia management. Results of the survey and audit demonstrated little or no difference between specialty groups. The results indicated that training in management skills and reducing practice barriers are important to improve resident physicians' management of patients with hypercholesterolemia. The use of a survey and audit provide a useful needs assessment for designing educational programs.     

Outcome of frozen embryo replacement cycles following elective cryopreservation of all embryos in women at risk of developing ovarian hyperstimulation syndrome

Aim: Our aim was to compare the outcome in subsequent frozen embryo replacement cycles in four groups of patients who had elective cryopreservation of all their embryos because they were considered to be at increased risk of developing severe ovarian hyperstimulation syndrome. Design: Sixty-two (91%) of 68 IVF cycles (68 patients) in which elective cryopreservation of all embryos was performed were analyzed. All patients continued on the GnRH agonist, buserelin, after oocyte recovery until the onset of vaginal bleeding. Frozen embryo replacement occurred in a hormone replacement cycle that started either on day 3 of the withdrawal bleed (group I;N=15) or after serum estradiol levels had fallen to <100 pmol/L (group II;N=16). The other patients commenced a frozen embryo replacement cycle several months later in either a hormone replacement (group III;N=15) or a natural (group IV;N=16) cycle. Results: Two patients developed severe ovarian hyperstimulation syndrome. There were no significant differences among the four groups regarding demographic variables, the dose of hMG used, and the clinical outcome. There was a higher but not significantly different clinical pregnancy rate in group I (26.7%), compared to group II (12.5%), group III (13.3%), and group IV (18.8%). Conclusions: Several options exist for the timing and protocol used for frozen embryo replacement in patients who had elective cryopreservation for the prevention of ovarian hyperstimulation syndrome, none of which was found to be clearly superior in this observational report.Presented at the 1994 Annual Conference of the American Fertility Society.     

Recombinant bone morphogenetic protein (BMP)-2 regulates costochondral growth plate chondrocytes and induces expression of BMP-2 and BMP-4 in a cell maturation-dependent manner

This study examined the effect of recombinant human bone morphogenetic protein-2 on several parameters of growth, differentiation, and matrix synthesis and on the endogenous production of mRNA of bone morphogenetic proteins 2 and 4 by growth plate chondrocytes in culture. Chondrocytes from resting and growth zones were obtained from rat costochondral cartilage and cultured for 24 or 48 hours in medium containing 0.05-100 ng/ml recombinant human bone morphogenetic protein-2 and 10% fetal bovine serum. Incorporation of [³H]thymidine, cell number, alkaline phosphatase specific activity, incorporation of [³H]proline into collagenase-digestible protein and noncollagenase-digestible protein, and incorporation of [³⁵S]sulfate were assayed as indicators of cell proliferation, differentiation, and extracellular matrix synthesis. mRNA levels T for bone morphogenetic proteins 2 andv4 were determined by Northern blot analysis. Recombinant human bone morphogenetic protein-2 increased the incorporation of [³H]thymidine by quiescent resting-zone and growth-zone cells in a similar manner, whereas it had a differential effect on nonquiescent cultures. At 24 and 48 hours, 12.5-100 ng/ml recombinant human bone morphogenetic protein-2 caused a dose-dependent increase in cell number and DNA synthesis in resting-zone chondrocytes. No effect was seen in growth-zone cell Recombinant human bone morphogenetic protein-2 stimulated alkaline phosphatase specific activity in resting-zone chondrocytes in a bimodal manner, causing significant increases between 0.2 and 0.8 ng/ml and again between 25 and 100 ng/ml. In contrast, alkaline phosphatase specific activity in growth-zone chondrocytes was significantly increased only between 12.5 and 100 ng/ml. Recombinant human bone morphogenetic protein-2 increased the production of both collagenase-digestible protein and noncollagenase-digestible protein by resting-zone and growth-zone cells, but incorporation of [³⁵S]sulfate was unaffected. Administration of recombinant human bone morphogenetic protein-2 also increased incorporation of [³H]uridine in both resting-zone and growth-zone chondrocytes; these cells produced mRNA for bone morphogenetic proteins 2 and 4. Bone morphogenetic protein-2 mRNA levels in both resting-zone and growth-zone chondrocytes increased in the presence of recombinant human bone morphogenetic protein-2; however, bone morphogenetic protein-4 mRNA levels in growth-zone cells decreased under its influence, and those in resting-zone cells were upregulated only with a dose of 10 ng/ml. This indicates that recombinant human bone morphogenetic protein-2 regulates chondrocyte proliferation, differentiation, and matrix production, and the effects are dependent on the stage of cell maturation. Resting-zone chondrocytes were more sensitive, suggesting that they are targeted by bone morphogenetic protein-2 and that this growth factor may have autocrine effects on these cells.     

Age and gender interactions on verbal memory performance.

Age and gender effects on verbal episodic memory are well established. However, the possibility of interactions between age and gender has been raised by studies linking estrogen and verbal memory performance, and by research suggesting gender differences in age-related cortical atrophy. We evaluated whether age by gender interactions in verbal memory were present. Subjects within three years of the median age of menopause were excluded from a large cohort of normal subjects, resulting in a younger sample (16-47 years) of 288 men and 285 women, and an older sample (55-89 years) of 201 men and 245 women. All subjects were administered the CVLT-2, a multiple-trial list-learning task. Verbal memory was negatively correlated with age for younger men, older men, and older women, but not for younger women. Multivariate analyses indicated age by gender interactions on memory for the younger group but not the older group. Results indicate that verbal memory declines with age for younger men but not younger women, whereas both older men and older women show age-related declines. These findings are consistent with hypotheses linking estrogen and verbal memory performance, and with imaging data suggesting that age-related hippocampal atrophy is found in younger men but not younger women. The role of estrogen on cognition in normal aging warrants further study.