Analysis of polycaprolactone scaffolds fabricated via precision extrusion deposition for control of craniofacial tissue mineralization

OBJECTIVES

Recurrence of cranial bone fusion following surgical resection in craniosynostosis patients commonly requires additional surgical procedures. Surgical implantation of engineered 3D scaffolds that control tissue mineralization could be utilized to diminish recurrence of fusion. This study investigated the ability of composite scaffolds to control tissue mineralization when cultured in vitro.

SETTING AND SAMPLE POPULATION

Precision-engineered scaffolds with calvarial cells were cultured in vitro at the Department of Orthodontics and Pediatric Dentistry, University of Michigan.

MATERIAL & METHODS

Polycaprolactone (PCL) scaffolds were fabricated using a novel precision extrusion deposition technique. Polyethylene glycol (PEG) hydrogel was coated onto select scaffolds to inhibit mineralization. MC3T3E1(C4) calvarial cells were cultured with scaffolds in media containing ascorbate and phosphate to promote osteoblast differentiation and mineralization. Scaffolds were assayed for osteoblast differentiation by alkaline phosphatase assay. Scaffolds were assayed for mineralization by nano-computed tomography (nano-CT) and by von Kossa staining of histologic sections.

RESULTS

MC3T3E1(C4) cells differentiated into osteoblasts and formed mineral when cultured on uncoated PCL scaffolds. MC3T3E1(C4) cells were significantly diminished in their ability to differentiate into osteoblasts when cultured on hydrogel-coated scaffold.

CONCLUSION

Results of this study indicate that this novel printing technology can be used to fabricate 3D scaffolds to promote and inhibit tissue mineralization in a region-specific manner. Future studies are needed to establish utility of such scaffolds in vivo.

The effects of tissue-non-specific alkaline phosphatase gene therapy on craniosynostosis and craniofacial morphology in the FGFR2C342Y/+ mouse model of Crouzon craniosynostosis

OBJECTIVES

Craniosynostosis, the premature fusion of cranial bones, has traditionally been described as a disease of increased bone mineralization. However, multiple mouse models of craniosynostosis display craniosynostosis simultaneously with diminished cranial bone volume and/or density. We propose an alternative hypothesis that craniosynostosis results from abnormal tissue mineralization through the downregulation of tissue-non-specific alkaline phosphatase (TNAP) enzyme downstream of activating mutations in FGFRs.

MATERIAL AND METHODS

Neonatal Crouzon (FGFRC342Y/+) and wild-type (FGFR+/+) mice were injected with lentivirus to deliver a recombinant form of TNAP. Mice were sacrificed at 4 weeks postnatal. Serum was collected to test for alkaline phosphatase (AP), phosphorus, and calcium levels. Craniofacial bone fusion and morphology were assessed by micro-computed tomography.

RESULTS

Injection with the TNAP lentivirus significantly increased serum AP levels (increased serum AP levels are indicative of efficient transduction and production of the recombinant protein), but results were variable and dependent upon viral lot and the litter of mice injected. Morphological analysis revealed craniofacial form differences for inferior surface (p=0.023) and cranial height (p=0.014) regions between TNAP lentivirus-injected and vehicle-injected Crouzon mice. With each unit increase in AP level, the odds of lambdoid suture fusion decreased by 84.2% and these results came close to statistical significance (p=0.068).

CONCLUSION

These results suggest that TNAP deficiency may mediate FGFR2-associated craniosynostosis. Future studies should incorporate injection of recombinant TNAP protein, to avoid potential side effects and variable efficacy of lentiviral gene delivery.

Comparison of erythrocyte membrane fatty acid contents in renal transplant recipients and dialysis patients

BACKGROUND

Alterations of erythrocyte membrane fatty acid (FA) composition play important roles in cellular function because they change the membrane microenvironment, including transmembrane receptors. The erythrocyte membrane oleic acid content is higher among patients with acute coronary syndrome and also in dialysis patients. However, available data are limited concerning erythrocyte membrane FA content in kidney transplant recipients (KTP). We sought to test the hypothesis that erythrocyte membrane FA content among KTP were different from those in dialysis patients.

METHODS

In this cross-sectional study, we recruited 35 hemodialysis, 33 peritoneal dialysis 49 KTP, and 33 normal control subjects (CTL). Their erythrocyte membrane FA content were measured by gas chromatography.

RESULTS

The mean ages of the enrolled dialysis patients, KTP, and CTL were 56.4 ± 10.1, 48.9 ± 10.4, and 49.5 ± 8.3 years, respectively. Mean kidney transplant duration was 89.8 ± 64.8 months and mean dialysis duration, 49.0 ± 32.6 months. The intakes of vegetable lipid and vegetable protein including total calories were significantly increased among KTP versus dialysis patients. Total cholesterol (P < .001) and high density lipoprotein cholesterol (HDL; P < .001) levels were significantly higher and C-reactive protein was significantly lower among KTP compared with dialysis patients. The erythrocyte membrane content of palmitoleic acid (P < .001) was significantly higher but oleic acid (P < .001) significantly lower in KTP compared with dialysis patients. The erythrocyte membrane contents of arachidonic acid and docosahexaenoic acid were significantly higher, and linoleic acid and the omega-6 FA to omega-3 FA ratio (P < .001) significantly lower in KTP compared with dialysis patients. The erythrocyte membrane content of oleic acid was independently associated with monounsaturated fatty acid (beta = 0.771, P < .001), eicosapentaeonic acid (beta = -0.244, P = .010), and HDL (beta = -0.139, P = .049) in KTP.

CONCLUSIONS

FA contents of erythrocyte membranes were significantly different in KTP compared with dialysis patients. These differences may have been associated with improved dietary intake and immunosuppression after kidney transplantation.

Ultra-rapid freezing of human multipronuclear zygotes using electron microscope grids

Developmental capacity of human multipronuclear (PN) zygotes cryopreserved using an ultra-rapid freezing method and electron microscope (EM) grids was studied. Multipronuclear zygotes obtained from a human IVF programme were used as an alternative to normal 2PN zygotes; they were divided into 3PN or >or =4PN zygotes and their in-vitro development and cryo-injury were compared according to PN number. EFS30, which consisted of 30% ethylene glycol, 18% Ficoll, 0. 5 mol/l sucrose and 10% fetal bovine serum with added modified Dulbecco's phosphate buffered saline was used as the freezing solution. After ultra-rapid freezing and thawing 85.5% of multipronuclear zygotes survived. A comparison of cleavage rates between the control and cryopreserved groups showed no significant difference (3PN; 81.3 and 85.4% and > or =4PN; 90.0 and 95.7% respectively). Comparing the in-vitro development after thawing up to blastocyst formation on day 5 after IVF, the outcome of the frozen 3PN group (22.0%) was not different from that of control 3PN group (38.5%), while the outcome of the frozen > or =4PN group (4.5%) was significantly lower than that of control > or =4PN group (44.4%) (P < 0.05).

The first discovery of an endemic focus of Heterophyes nocens (Heterophyidae) infection in Korea

A highly endemic focus of human infection with Heterophyes nocens (Heterophyidae) was discovered from a small coastal village of Shinan-gun, Chollanam-do, for the first time in Korea. Fecal examinations by cellophane thick smear and formalin-ether sedimentation techniques revealed 42.9% heterophyid egg positive rate out of 98 inhabitants examined. It was difficult to confirm the species of heterophyids only by eggs. In order to collect the adult flukes, the egg positive cases were treated with 10 mg/kg single dose of praziquantel and purged with magnesium sulfate, and the adult worms were collected from the diarrheic stools. From each of 18 cooperative patients 1 to 1,124 (total 4,730) H. nocens worms were recovered, together with a few to large numbers of heterophyids (Pygidiopsis summa, Stictodora fuscatum) and/or gymnophallids (Gymnophalloides seoi). It is speculated that H. nocens might be widely distributed along the southwestern coastal areas where the brackish water fish such as the mullets or gobies are popularly eaten raw.

[A clinical study for promoting quality nursing care in a university hospital]

The purpose of this study was to develop a new nursing unit which can meet changing health care needs, enhance patients' satisfaction and nurses' job satisfaction, and finally guarantee quality nursing care with present manpower. For this, one medical unit was selected as a unit for quality care. And one medical unit which is similar in staffing and patients' characteristics was selected as a control unit. To assess present problems and identify the remedies to the problems a hospital-wide survey and a workshop were performed. According to the survey results, educational programs and improvement of the facilities and equipment supply system, managerial support for interdepartmental cooperation and intensification of bed-side nursing care were adopted as main principles for operating model unit. This model unit was operated for 3 months from Sep. 1, 1992 to Nov. 30, 1992. To evaluate the effectiveness of the model unit, direct/indirect nursing care hours, patients' satisfaction to nursing care, nurses' job satisfaction, and quality care index were measured. Direct/indirect nursing care hours were compared with that of the control unit, and patients' and nurses' satisfaction and quality care index were measured before and after operating model unit and compared with each other. The results of the study were as follows; 1. In the model unit mean direct nursing care hours per each shift was 146.88 minutes and indirect nursing care hours was 354.72 minutes. The ratio of the direct nursing care hour to indirect nursing hour was 29.6:70.4 and that of the control unit was 26.9:73.1. Direct nursing care hour in model unit was longer than that of the control unit. But, the difference was not significant. In subcategories of direct nursing care, the time spent in mobility and exercise, conservation of body temperature, hygiene, and communication and health education were longer than that of the control unit. 2. Indirect nursing care hour in model unit was shorter than that of the control unit. But, the difference was not significant. In subcategories of indirect nursing care, the time spent in drug management and ward arrangement was shorter than that of the control unit. 3. Patients' satisfaction to nursing care was increased significantly after operating the model unit (T = -3.48, P = 0.002) and satisfaction to subcategories of physical comfort measure, psychological care, and unit management components were significantly higher than before.(ABSTRACT TRUNCATED AT 400 WORDS)

[A study on comparisons of ice bag and heat lamp for the relief of perineal discomfort]

Perineal discomfort from episiotomy continues to be a problem for many postpartum women. The purposes of this study were to compare the effect of ice bag and heat lamp for the relief of perineal discomfort and to identify the sustaining time of each effect. Forty women took ice bag and heat lamp with random assignment of initial therapy. Women rated the degree of perineal discomfort before and after each therapy and at half-hour, tow-hour and four-hour intervals after each therapy. A discomfort scale, 18cm graphic rating scale, was used. The results of the study were as follows: 1. The ice bag group showed significantly lower discomfort score than the heat lamp group at the half-hour and two-hour intervals after therapy. 2. The ice bag group showed significantly lower discomfort score for 4hrs after than before therapy, but the heat lamp group did not show significantly lower discomfort score. 3. Neither the type of episiotomy nor the previous experience of heat therapy influenced on the effect of ice bag relieving the perineal discomfort. Therefore ice bag was significantly more effective in relieving perineal discomfort than heat lamp. Subjective responses of patients who took both therapy were very favorable toward ice bag. I suggested that nurses should provide women with adequate information about the use of ice bag and encourage to apply ice bag instead of heat lamp after episiotomy in order to promote the relief of perineal discomfort and the healing of perineal wound.

On the role of Fe2+ in bacterial photosynthesis. The effect of biosynthetic substitution of Fe2+ by Mn2+ on the electron transfer step Q-1Q2----Q1Q-2 in reaction centers

A test of the 'iron-wire' hypothesis for the role of Fe2+ in promoting the electron transfer between the primary (Q1) and secondary (Q2) quinones in bacterial reaction centers of Rhodopseudomonas sphaeroides strain R-26.1 has been conducted. Kinetics of this step, P+Q-1Q2----P+Q1Q-2, and of recombination with the oxidized donor, P+Q-1----PQ1 and P+Q-2----PQ2, were followed optically at 4 degrees C in normal iron-containing reaction centers and in reaction centers having 58% Mn2+, replacing Fe2+. This significant replacement is accomplished biosynthetically by control of the growth conditions, and so should preserve the native interactions between the cofactors. There are no significant differences observed in the recombination kinetics of the two types of reaction centers. The electron transfer between the quinones was observed to show apparent biphasic kinetics with major components of approx. 170 microseconds and 1.5 ms at 4 degrees C and pH = 7.5. There is no statistically significant difference observed between the two types of reaction centers. This major change in the electronic structure of the metal and the unaltered kinetics discount the likelihood of any direct orbital participation of the metal in the electron transfer between the quinones.