A retrospective study of implant-abutment connections on crestal bone level.

This study compared the effects of external hex, internal octagon, and internal Morse taper implant-abutment connections on the peri-implant bone level before and after the occlusal loading of dental implants. Periapical radiographs of 103 implants (63 patients) placed between 2002 and 2010 were collected, digitized, standardized, and classified into groups based on the type of implant-abutment connection. These radiographs were then analyzed with image-processing software to measure the peri-implant crestal bone change during the healing phase (4 months after implant placement) and at loading phases 1 and 2 (3 and 6 months after occlusal loading, respectively). A generalized estimating equation method was employed for statistical analysis. The amount of peri-implant crestal bone change differed significantly among all time-phase pairs for all 3 types of implant-abutment connection, being greater in the healing phase than in loading phase 1 or 2. However, the peri-implant crestal bone change did not differ significantly among the 3 types of implant-abutment connections during the healing phase, loading phase 1, or loading phase 2. This retrospective clinical study reveals that the design of the implant-abutment connection appears to have no significant impact on short-term peri-implant crestal bone change.

Quality of life, health satisfaction and family impact on caregivers of children with developmental delays.

OBJECTIVE: To study the quality of life, health satisfaction and family impact on caregivers of children with developmental delays in Taiwan. DESIGN: Cross-sectional study. SUBJECTS: The caregivers of children with diagnoses of developmental delays recruited from a teaching hospital in northern Taiwan. METHODS: The main caregivers of 48 male and 22 female children with developmental delays were recruited. WHOQOL-BREF for health-related quality of life (HRQOL), PedsQL-Health Satisfaction for health satisfaction, PedsQL-Family Impact Module and Impact on Family Scale for family impact were evaluated. The correlation of caregivers' HRQOL, health satisfaction and family impact were also studied. RESULTS: Caregivers in nuclear families had higher health satisfaction scores (78.2 for nuclear families vs. 66.9 for extended families, P < 0.05) when assessed by the PedQL-Health Satisfaction questionnaire. Children's age was negatively correlated with family impact, including parent (-0.272, P = 0.023), family (-0.262, P = 0.029) and total scores (-0.281, P = 0.018) as assessed using the PedsQL-Family Impact Module. CONCLUSION: A negative relation between impact of burden and child's age suggests that family members gradually adapt to the delayed developmental status in their children as they grow. Caregivers in nuclear families having higher health satisfaction than those in extended families may be due to Chinese cultural effects.

Herpes zoster during varicella.

A 4-year-old boy had varicella infection. Two days later vesicular lesions clustered within the left 10th thoracic dermatome. Varicella-zoster virus IgM antibody in serum was positive. He was diagnosed with varicella infection combined with herpes zoster. This is the first case report in the medical literature.

Neurocutaneous melanosis with epilepsy: report of one case.

Neurocutaneous melanosis is a rare congenital syndrome characterized by the association of large or multiple congenital melanocytic nevi and benign or malignant melanotic tumors in the central nervous system. Patients with neurocutaneous melanosis usually have neurological symptoms early in life that progress rapidly due to the development of increased intracranial pressure or malignant melanoma. We report a 2-month-old female infant with multiple congenital melanocytic nevi and frequent seizure attacks. Magnetic resonance imaging of the brain demonstrated several regions compatible with melanotic deposits. During follow-up for one year, she had normal development and was seizure-free under the treatment of phenobarbital and valproic acid. We suggest that infants with large or multiple congenital melanocytic nevi should receive regular clinical check-up and brain imaging to exclude the possibility of central nervous system lesions.

Brain derived neurotrophic factor is an endothelial cell survival factor required for intramyocardial vessel stabilization.

Brain derived neurotrophic factor, BDNF, is a neurotrophin best characterized for its survival and differentiative effects on neurons expressing the trk B receptor tyrosine kinase. Although many of these neurons are lost in the BDNF(-)(/)(- )mouse, the early postnatal lethality of these animals suggests a wider function for this growth factor. Here, we demonstrate that deficient expression of BDNF impairs the survival of endothelial cells in intramyocardial arteries and capillaries in the early postnatal period, although the embryonic vasculature can remodel into arteries, capillaries and veins. BDNF deficiency results in a reduction in endothelial cell-cell contacts and in endothelial cell apoptosis, leading to intraventricular wall hemorrhage, depressed cardiac contractility and early postnatal death. Vascular hemorrhage is restricted to cardiac vessels, reflecting the localized expression of BDNF and trk B by capillaries and arterioles in this vascular bed. Conversely, ectopic BDNF overexpression in midgestational mouse hearts results in an increase in capillary density. Moreover, BDNF activation of endogenous trk B receptors supports the survival of cardiac microvascular endothelial cells cultured from neonatal mice. These results establish an essential role for BDNF in maintaining vessel stability in the heart through direct angiogenic actions on endothelial cells.

Trk C receptor signaling regulates cardiac myocyte proliferation during early heart development in vivo.

Neurotrophin-3 (NT-3) is a member of the neurotrophin family of growth factors, best characterized by its survival- and differentiation-inducing effects on developing neurons bearing the trk C receptor tyrosine kinase. Through analysis of NT-3 and trk C gene-targeted mice we have identified NT-3 as critically regulating cardiac septation, valvulogenesis, and conotruncal formation. Although these defects could reflect cardiac neural crest dysfunction, the expression of NT-3 and trk C by cardiac myocytes prior to neural crest migration prompted analysis of cell-autonomous actions of NT-3 on cardiac myocytes. Retroviral-mediated overexpression of truncated trk C receptor lacking kinase activity was used to inhibit activation of trk C by endogenous NT-3, during early heart development in ovo. During the first week of chicken development, expression of truncated trk C reduced myocyte clone size by more than 60% of control clones. Direct mitogenic actions of NT-3 on embryonic cardiac myocytes were demonstrated by analysis of BrdU incorporation or PCNA immunoreactivity in control and truncated trk C-expressing clones. Inhibition of trk C signaling reduced cardiac myocyte proliferation during the first week of development, but had no effect at later times. These studies demonstrate that endogenous NT-3:trk C signaling regulates cardiac myocyte proliferation during cardiac looping and the establishment of ventricular trabeculation but that myocyte proliferation becomes NT-3 independent during the second week of embryogenesis.

An approach for enhancing heterologous production of Providencia rettgeri penicillin acylase in Escherichia coli.

Heterologous production of Providencia rettgeri penicillin acylase (PAC) was optimized in Escherichia coli. Several factors, including carbon, temperature, and host effects, were identified to be critical for the enzyme overproduction. The optimum culture conditions for the enzyme production vary for different host/vector systems. With the optimization, both volumetric and specific PAC activities could be significantly improved by more than 50-fold compared to the native expression in P. rettgeri. The heterologous production could be possibly limited by translation or posttranslational steps, depending on the culture temperature and host/vector system. To our knowledge, this is the first evidence demonstrating the limiting step for the production of P. rettgeri PAC and the existence of the P. rettgeri PAC precursor.

Trk C signaling is required for retinal progenitor cell proliferation.

Although neurotrophin actions in the survival of specific retinal cell types have been identified, the biological functions for neurotrophin-3 (NT-3) in early retinal development remain unclear. Having localized NT-3 and trk C expression at early developmental stages when retinal neuroepithelial progenitor cells predominate, we sought to modulate NT-3 signaling in these cells by overexpressing a truncated isoform of the NT-3 receptor, trk C. We have demonstrated that this non-catalytic receptor can inhibit NT-3 signaling when coexpressed with the full-length kinase-active trk C receptor. Using a replication-deficient retrovirus to ectopically express the truncated trk C receptor to limited numbers of progenitor cells in ovo, we examined the effects of disrupted trk C signaling on the proliferation or differentiation of retinal cells. Clones expressing truncated trk C exhibited a 70% reduction in clone size, compared with clones infected with a control virus, indicating that inhibition of trk C signaling decreased the clonal expansion of cells derived from a single retinal progenitor cell. Additionally, impaired NT-3 signaling resulted in a reduction of all retinal cell types, suggesting that NT-3 targets retinal precursor cells rather than differentiated cell types. BrdU labeling studies performed at E6 indicate that this reduction in cell number occurs through a decrease in cell proliferation. These studies suggest that NT-3 is an important mitogen early in retinal development and serves to establish the size of the progenitor pool from which all future differentiated cells arise.

oto is a homeotic locus with a role in anteroposterior development that is partially redundant with Lim1.

Genetic control of mammalian head development involves mechanisms that are shared with trunk development as well as mechanisms that are independent. For example, mutations in the nodal gene disrupt axis formation and head development while mutations in the Otx2 or Lim1 genes block head development without disrupting development of the trunk. We show here that the oto mutation on mouse chromosome 1 defines a locus with a critical role in anterior development. The oto mutation disrupts development of the telencephalic and optic vesicles, the pharyngeal endoderm and the first branchial arch. Also, oto embryos have dose-dependent, posterior homeotic transformations throughout the axial skeleton. To further dissect the role of the oto locus in head development, we crossed mice carrying oto and Lim1 mutations. Interactions between the two mutations indicate that the role of oto in the regulation of head development is partially redundant with that of Lim1. The phenotype of oto embryos points to an early and critical role for oto in the development of forebrain subregions. Transformations of the vertebrae in oto embryos reveal a Lim1-independent role in the establishment of positional information in the trunk.

Effect of SecB chaperone on production of periplasmic penicillin acylase in Escherichia coli.

The effect of SecB chaperone on production of periplasmic penicillin acylase (PAC) in Escherichia coli was investigated. It appears that formation of PAC required the function of SecB chaperone and the amount of SecB required was at a basal level. The secB mutant was defective in production of PAC, and the impairment could be complemented by extrachromosomally supplementing SecB in trans. The function of SecB might be primarily stabilizing the cytoplasmic PAC precursors. Overproduction of SecB chaperone usually resulted in an increase in the amount of PAC precursors without enhancing PAC activity. In addition, most of the PAC precursors were located in the periplasm, suggesting that formation of active PAC was likely limited by periplasmic processing steps.

Manipulation of carbon assimilation with respect to expression of the pac gene for improving production of penicillin acylase in Escherichia coli.

A strategy of genetically manipulating carbon assimilation with respect to expression of the pac gene was employed for overproduction of recombinant penicillin acylase (PAC). Two expression plasmids of pCLL2902 and pCLL3201, which contain the pac coding region but differ in the pac regulatory region, were constructed for the production experiments. Expression of the pac gene was subjected to phenyl acetic acid (PAA-) induction and glucose catabolite repression for pCLL3201, whereas it was subjected to neither of the two transcriptional regulations for pCLL2902. The specific PAC activity for strains harboring pCLL2902 was significantly higher than that for strains harboring pCLL3201 due to an improved transcription efficiency. In addition, no inclusion bodies were observed upon production of PAC using the current expression systems. The results suggest that using the native pac promoter instead of a strong promoter such as tac for regulation is a feasible approach for production of PAC. The impact of the current expression systems is also significant from a process viewpoint since, using strains harboring pCLL2902, not only could glucose replace PAA as a carbon source of Escherichia coli cultures for production of PAC but also the volumetric PAC activity was highly improved.

Genetic manipulation to identify limiting steps and develop strategies for high-level expression of penicillin acylase in Escherichia coli.

We have identified the bottleneck steps limiting expression of penicillin acylase (PAC) through comparison of the expression performance for various PAC-expression vectors constructed by genetically modulating the efficiencies of transcription and/or translation of the pac gene. To our knowledge, this is the first report demonstrating that expression of PAC could be limited by various steps, such as transcription, translation, and post-translational steps (i.e. translocation and periplasmic processing), depending on the host/vector systems. Results also indicate that the structure of the wild-type pac gene might not be optimal for direct use in production of PAC using recombinant DNA technology. To improve the gene expression, transcription was enhanced by manipulating certain DNA bases in the pac regulatory region, whereas translation was enhanced by enlarging the spacing between the ribosome binding site and the ATG initiation codon to increase the initiation efficiency. The information is useful in terms of developing genetic strategies for overproduction of recombinant PAC in Escherichia coli.

Holocord intramedullary spinal cord astrocytoma: report of one case.

Intramedullary spinal cord astrocytoma in infants is relatively uncommon. Its occurrence is usually confined to the cervical and cervicothoracic regions. In this paper, we report on the case of a 4-month old male infant with low grade holocord intramedullary spinal cord astrocytoma. He had developed progressive weakness of the lower extremities over a month period. Neurological examination revealed flaccid paraplegia as well as complete loss of all modalities of sensation below the T10 level. MRI revealed a large intramedullary mass which was found to be an intramedullary astrocytoma at surgery. This case report presents the clinical features, radiographic findings, and treatment and outcome for this patient together with a review of relevant literature.

Simulatory effect of porcine insulin on noradrenaline secretion in guinea-pig ileum myenteric nerve terminals.

1. The effect of insulin on the release of noradrenaline (NA) from nerve terminals was investigated in isolated ileal synaptosomes of guinea-pig. Release was determined as the amount of NA, quantified by h.p.l.c.-electrochemical detection, from samples incubated with insulin minus that in parallel blanks treated with some volume of vehicle. 2. Porcine insulin stimulated the secretion of NA in a concentration-dependent manner from 0.01 i.u. ml-1, while the value of lactate dehydrogenase in the incubated medium was not influenced by insulin. 3. The presence of insulin receptors in this preparation was illustrated by immunoblotting with insulin receptor monoclonal antibodies. 4. The release of NA by insulin was reduced by guanethidine and bretylium and it was markedly lowered in the samples obtained from guinea-pigs that had received an intraperitoneal injection of DSP-4, the noradrenergic neurotoxin. 5. Tetrodotoxin attenuated the action of insulin at concentrations sufficient to block sodium channels. The depolarizing effect of insulin on the membrane potential was also illustrated by a concentration-dependent increase in the fluorescence of bisoxonol, a potential-sensitive dye. 6. The action of insulin was attenuated by removal of calcium chloride from the bathing medium. The induction of calcium ion influx by insulin into the synaptosomes is supported by the inhibitory effects of the calcium channel blockers omega-conotoxin GVIA (for the N-type channels) and nifedipine (for the L-type channels). 7. These findings suggest that insulin can stimulate NA release from noradrenergic terminals via activation of calcium influx.

Pseudomonas aeruginosa endophthalmitis in prematurity: report of two cases.

Invasive bacterial eye infections in the neonate range from perforating keratitis to endophthalmitis. Endophthalmitis secondary to Pseudomonas aeruginosa has gained clinical and therapeutic importance since mortality rates are high and prognosis concerning preservation of vision is poor, especially in premature infants. We presented two cases with meningitis, septicemia and P. aeruginosa endophthalmitis. If premature infants develop a sepsis-like picture with cloudy cornea and purulent conjunctivitis, we have to consider the possibility of endophthalmitis and do a full ophthalmologic evaluation. Treatment should be started early and consists of systemic antibiotic therapy, as in septicemia. As P. aeruginosa spreads easily, prompt isolation and strict handwashing are indicated.

Functional activity of sporamin from sweet potato (Ipomoea batatas Lam.): a tuber storage protein with trypsin inhibitory activity.

Sporamin accounts for about 60% to 80% of total soluble protein in sweet potato tubers, and the predicted protein sequence of sporamin shares significant amino acid sequence identity with some Kunitz-type trypsin inhibitors. We constructed three recombinant plasmids with cDNAs that encode preprosporamin, prosporamin, and sporamin, and these three were expressed in Escherichia coli cells as fusion proteins. All three forms of sporamin expressed in E. coli were shown to have strong inhibitory activity to trypsin in vitro, suggesting that post-translational modifications are not essential for trypsin inhibitory activity. Northern blot analysis showed that sporamin transcripts could be systemically induced in leaf tissue of sweet potato by wounding. Therefore, sporamin may have a defense role as a protease inhibitor, in addition to its role as a storage protein.

Sweet potato (Ipomoea batatas) trypsin inhibitors expressed in transgenic tobacco plants confer resistance against Spodoptera litura.

A sweet potato (Ipomoea batatas cv. Tainong 57) trypsin inhibitor gene was introduced into tobacco plants (Nicotiana tabaccum cv. W38) by Agrobacterium tumefaciens- mediated transformation. From 30 independent transformants, three lines with high level of expression were further analyzed. The trypsin inhibitor gene, under control of the 35S CaMV promoter, led to the production of the trypsin inhibitor proteins up to 0.2% of the total protein. In insecticidal bioassays of transgenic tobacco plants, larval, growth of Spodoptera litura (F.), the tobacco cutworm, was severely retarded as compared to their growth on control plants. This observation implied that expression of sweet potato trypsin inhibitor can provide an efficient method for crop protection.

Guillain-Barré syndrome in children: a cooperative study in Taiwan.

Seventy-two children with Guillain-Barré syndrome (GBS), diagnosed at 11 major teaching hospitals in Taiwan during the period 1986-1990, were studied retrospectively. There were 44 males and 28 females ranging in age from 7 months to 15 years. Preceding events could be traced in 61 patients (85%), including antecedent infection in 59 patients and previous vaccination in 2. As well as the consistent pictures of progressive weakness and generalized hyporeflexia, there were sensory complaints (26%), cranial nerve lesions (46%), respiratory failure (14%) and autonomic dysfunction (25%). Motor symptoms reached a maximum within 20 days in 88% of the patients, with the plateau lasting less than 2 weeks in 75%, and became stable within 3 months in 76%. Overall outcome showed complete recovery in 73% of the patients within 6 months after onset. Four (5.6%) had recurrence, and there was no mortality. The present study revealed that the annual incidence of GBS in Taiwan can be estimated roughly as 0.66 per 100,000 and that the course of childhood GBS is relatively benign.

Acute duodenal ulcer.

A series of 31 infants and children with acute duodenal ulcer verified by endoscopy was studied over an eight year period. Eighteen (58%) of them were under 2 years of age. The most common symptom was upper gastrointestinal bleeding (n = 27, 87%). Twenty nine patients (94%) had a preceding illness characterised by diarrhoea, upper respiratory tract infection, or fever, which was not necessarily treated with antipyretic drugs. Initial endoscopy showed that ulcer lesions were solitary in 14 patients and present on the anterior wall (n = 11), posterior wall (n = 2), or both (n = 1). Multiple ulcers were found in 17 patients, and present in the bulb with (n = 6) or without (n = 11) extension into the second part of duodenum. The most conspicuous finding was the irregularly shaped ulcers seen in eight young children with similar clinical and endoscopic features. Sixteen patients were re-endoscoped one to two weeks after the initial examination; the ulcers had entirely disappeared in 13, and there were only small residual ulcers in three. Thirty patients were treated medically and only one (with uncontrollable haemorrhage) required operation. Most patients were symptom free two to six years after the initial diagnosis. Our results suggest that young children may develop acute duodenal ulcers after viral illnesses whether or not they are treated with drugs, mainly antipyretics. This kind of acute duodenal ulcer usually heals quickly irrespective of the morphology, site, and number of ulcers.