[Application of acellular dermal matrix in periodontal soft tissue augmentation surgery].

The substitute materials of autologous tissue graft for periodontal soft tissue augmentation surgery develop rapidly. The use of substitute material can avoid the second operation area, shorten the operation time, reduce the postoperative reaction and pain, and is not limited by the quantity, suitable for a wide range of cases. In this paper, the characteristics, histological study, clinical application and therapeutic effect of acellular dermal matrix as a substitute material for autologous tissue transplantation were introduced to provide reference for clinical work.

[Evaluation of the effects of plaque and inflammation control on treatment of gingival enlargement].

Gingival enlargement or hypertrophy is one of the common clinical symptoms in patients with periodontitis. Plaque stimulation, hormones and drug use could be the promoting factors for the occurrence of gingival enlargements. This paper reviews the literature on the pathogenesis, treatment methods and the effect of plaque and inflammation control in the treatment of various types of gingival hypertrophy. The therapeutic effect of controlling plaque and inflammation on various types of gingival hypertrophy is also discussed and the treatment scheme of gingival hypertrophy is proposed, which may provide reference for clinical work.

The lateral "backdoor" approach to open thyroid surgery: A comparative study.

INTRODUCTION: The traditionally taught technique for conventional open thyroidectomy is via a midline splitting of the strap muscles following a skin crease neck incision - midline approach (MA). The lateral "backdoor" approach (LA) uses the same central neck incision but approaches the thyroid gland between the anterior border of sternocleidomastoid (SCM) and strap muscles. This technique is usually reserved for re-do thyroid surgery. We compared the results of the two approaches in patients undergoing conventional thyroidectomy for the first time. METHODS: A case-control study was performed on 90 patients undergoing conventional open thyroidectomy from 2012 to 2014. The first 45 patients underwent MA and subsequent 45 patients underwent LA. All patients were given 10 ml of 1% Marcaine infiltration into the neck incision before closure. Basic demographic data, operative time, incision length, weight of gland, need for transection of strap muscles and complications were recorded. Revision thyroid surgery and minimally invasive thyroid operations were excluded. RESULTS: The demographics, operative timing, gland weight and incisional length showed no significant difference. Post-operative pain was significantly lower in the LA group. 5 patients (11%) in MA group needed horizontal transection of strap muscles to extract large goitres compared to 1 patient (2.2%) in the LA group. No major complications occurred in either group. CONCLUSION: The LA method is as safe as the midline technique with comparable operative time and significantly lower pain scores. It avoids midline separation and suturing of strap muscles and reduces the need for strap muscle transection to removal large goitres.

Dual-faced SH3BGRL: oncogenic in mice, tumor suppressive in humans.

Despite abundant data supporting c-Src as a metastasis-promoting oncogene, activating mutations of c-Src are rare. This suggests that trans-interacting proteins may have a critical role in regulating c-Src activation. Here, we first report the discovery of Src homology 3 (SH3) domain-binding glutamic acid-rich-like protein (SH3BGRL), a novel c-Src activator in mice. Ectopic expression of murine SH3BGRL (mSH3BGRL) strongly promoted both tumor cell invasion and lung metastasis. Molecularly, mSH3BGRL specifically bound the inactive form of c-Src phosphorylated at Tyr527, promoting Tyr416 phosphorylation of c-Src and subsequent FAK-mediated activation of ERK and AKT signaling pathways. Targeting endogenous c-Src alone was sufficient to abolish mSH3BGRL-induced cancer metastasis in vivo. Unexpectedly, human SH3BGRL (hSH3BGRL) in turn suppressed tumorigenesis and metastasis in nature. We attempted site-specific reversion of hSH3BGRL amino-acid sequence to mSH3BGRL and found V108A substitution sufficient to restore SH3BGRL function as a c-Src activator and metastasis promoter. Notably, the somatic mutation R76C of hSH3BGRL can similarly act as hSH3BGRL-V108A and mSH3BGRL in tumorigenesis and metastasis. Our results uncover an evolutionarily controversial role of SH3BGRL in driving tumor metastasis through c-Src activation, and suggests that hSH3BGRL mutation status could be relevant to cancer diagnosis and therapy.

ADAR1 deaminase contributes to scheduled skeletal myogenesis progression via stage-specific functions.

Adenosine deaminases acting on RNA 1 (ADAR1) catalyzes cellular RNA adenosine-to-inosine editing events on structured RNA molecules. In line with this critical role, ADAR1 exhibits ubiquitous expression and is essential for embryonic development. However, regulation and developmental significance of this RNA editor in a spatiotemporal context are largely elusive. Here we unveil a novel tissue-specific role of ADAR1 in skeletal myogenesis. ADAR1 expression displayed programmed alteration that is coordinated with differentiation cues, and mediated negatively by miRNA-1/206. Coincidently, ADAR1 exerts stage-dependent functions-suppression of apoptosis at the onset of differentiation and preservation of timely myotube formation through later phase. Furthermore, the post-transcriptional aspect of its myogenic role was illustrated by the spectrum of binding RNAs, as revealed by high-throughput approach, as well as by direct regulation of myogenesis-associated targets such as dynamin 1/2 (Dnm1/2) and annexin A4. Consequently, maintenance of target gene expression profiles likely contributes to a state of cytoskeleton and membrane dynamics that is amenable to myoblast morphogenesis. Collectively, these findings uncover a critical link of ADAR1 to myogenesis, and further highlight an epigenetic mechanism by which ADAR1 and miR-1/206 interplay to control scheduled myoblast-myotube transition.

Population genetic structure of the tropical moss Acanthorrhynchium papillatum as measured with microsatellite markers.

Mosses and other bryophytes are vital components of forests, because they sustain a tremendous diversity of invertebrates and influence significant ecological functions. There have been few studies on moss population diversity in Southeast Asia, despite the escalating deforestation in this region of rich biodiversity. The genetic diversity of the tropical moss Acanthorrhynchium papillatum (Harv.) Fleisch., collected from forested areas in Singapore and Peninsular Malaysia, was elucidated using eight microsatellite markers developed for this species. Significant levels of allelic and haplotypic diversity were observed among clumps of the moss. Differences in allelic richness and genotypic diversity among the populations were higher in less disturbed forests compared to the more disturbed areas, suggesting that genetic diversity is affected by habitat quality. Genetic diversity levels within the clumps studied were low, indicating that vegetative reproduction was more important within clumps than sexual reproduction. However, multilocus genotypes of samples within the clumps studied were not all alike, providing evidence of microsatellite mutation or of occasional sexuality. Despite the isolation of populations, A. papillatum can introduce genetic variability by mutation among vegetatively propagated individuals. This study provides baseline information on the genetic diversity of A. papillatum tropical rain forests.

Basic fibroblast growth factor modulates cell cycle of human umbilical cord-derived mesenchymal stem cells.

BACKGROUND: Mesenchymal stem cells (MSC) have great potential in regenerative medicine, immunotherapy and gene therapy due to their unique properties of self-renewal, high plasticity, immune modulation and ease for genetic modification. However, production of MSC at sufficient clinical scale remains an issue as in vitro generation of MSC inadequately fulfils the demand with respect to patients. OBJECTIVES: This study has aimed to establish optimum conditions to generate and characterize MSC from human umbilical cord (UC-MSC). MATERIALS AND METHODS: To optimize MSC population growth, basic fibroblast growth factor (bFGF) was utilized in culture media. Effects of bFGF on expansion kinetics, cell cycle, survival of UC-MSC, cytokine secretion, expression of early stem-cell markers and immunomodulation were investigated. RESULTS: bFGF supplementation profoundly enhanced UC-MSC proliferation by reducing population doubling time without altering immunophenotype and immunomodulatory function of UC-MSC. However, cell cycle studies revealed that bFGF drove the cells into the cell cycle, as a higher proportion of cells resided in S phase and progressed into M phase. Consistent with this, bFGF was shown to promote expression of cyclin D proteins and their relevant kinases to drive UC-MSC to transverse cell cycle check points, thus, committing the cells to DNA synthesis. Furthermore, supplementation with bFGF changed the cytokine profiles of the cells and reduced their apoptotic level. CONCLUSION: Our study showed that bFGF supplementation of UC-MSC culture enhanced the cells' growth kinetics without compromising their nature.

Compression neuropathy of the common peroneal nerve secondary to a ganglion cyst.

There are various causes of the common peroneal nerve palsy. However, common peroneal nerve palsy caused by ganglia are uncommon. We hereby present a case of a 55-year-old man with a 1 week history of foot drop and swelling in the region of the right leg. Physical examination and nerve conduction study studies confirmed a diagnosis of common peroneal nerve palsy. Magnetic resonance imaging (MRI) revealed a lobulated, elongated cystic-appearing mass anterior to the head of fibula. Surgical decompression of the nerve with removal of the mass was performed. Surgical pathology reports confirmed the diagnosis of a ganglion cyst. Findings on physical examination, nerve conduction study and MRI results of this interesting case are being discussed. We wish to highlight that even a tumour which is benign and within the nerve sheath can cause compression.

High prevalence of human papillomavirus DNA detected in cervical swabs from women in southern Selangor, Malaysia.

Persistent high-risk human papillomavirus (HPV) infection is known to play an important role in the genesis of cervical cancer. Since new screening and prevention strategies, namely improved HPV testing and HPV vaccination have been aggressively promoted recently, it is crucial to investigate the HPV distribution in Malaysia in order to maximize their cost-effectiveness. This study was therefore conducted to assess the HPV type distribution in the most populous region, the state of Selangor. A total of 200 cervical swab samples were collected in two health-screening campaigns, and also from women attending obstetrics and gynecology clinics in several hospitals in Selangor. DNA extraction was performed and HPV DNA was detected via nested PCR using MY09/MY11 as outer primers and GP5+/GP6+ as inner primers which target the L1 gene of the viral genome. The purified PCR products were subjected to automated DNA sequencing to determine the HPV genotype. Out of 180 ß-globin positive samples, 84 (46.7%) were positive for HPV DNA. The most common HPV type found was high-risk oncogenic type 16 (40%), followed by HPV type 18 (3.3%), HPV 33 (1.7%), HPV 31 (0.6%), and low-risk HPV 87 (0.6%). Our study confirmed that nested PCR method is highly sensitive in detecting HPV DNA even in low risk patients. Since a relatively high prevalence rate of HPV infection was found in this population, prompt healthcare policy changes to bring about implementation of early HPV vaccination program is desirable to prevent a high incidence of cervical cancer.

Lichens as bioindicators of atmospheric heavy metal pollution in Singapore.

Lichens have been used as bioindicators in various atmospheric pollution assessments in several countries. This study presents the first data on levels of heavy metals (As, Cd, Cu, Ni, Pb, and Zn) in lichens at different locations in Singapore, Southeast Asia. Singapore is a fully industrialised island nation, with a prevailing tropical climate and a population of 4 million people within a confined land area of less than 700 km2. The ubiquitous lichen species, Dirinaria picta was collected from six sample sites across Singapore and analysed for heavy metals using inductively coupled plasma mass spectrometry (ICPMS). No significant relationship existed between metal levels in lichen and soil, indicating that accumulated metals in lichen are primarily derived from the atmosphere. Peak concentrations of zinc (83.55 microg g(-1)), copper (45.13 microg g(-1)) and lead (16.59 microg g(-1)) in lichens were found at Sembawang, Jurong and the National University of Singapore campus which are locations associated with heavy petroleum and shipping industries, and road traffic respectively. The mean heavy metal levels of lichen samples in Singapore were found to be at the upper range of values reported in the literature for temperate countries.

Marjolin's ulcer--a near forgotten entity.

We report a case of a 55-year-old man who presented with a 6-month history of a fungating ulcer on the right hand at the site of a previously healed ulcer that had been present for 40 years. Histopathological examination of four-quadrant biopsy specimens showed a moderately differentiated squamous cell carcinoma (SCC). A transradiocarpal amputation with stump closure using radial flap was performed as it was not possible to achieve a functionally and cosmetically acceptable hand after a wide excision with 2 cm tumour-free margin. It is our intention to highlight this rare condition as reminder to consider this entity as a differential diagnosis of chronic non-healing skin ulcer.

Localization and targeting of the VP14 epoxy-carotenoid dioxygenase to chloroplast membranes.

Abscisic acid (ABA) is a key regulator of seed dormancy and plant responses to environmental challenges. ABA is synthesized via an oxidative cleavage of 9-cis epoxy-carotenoids, the first committed and key regulatory step in the ABA biosynthetic pathway. Vp14 of maize encodes an epoxy-carotenoid dioxygenase that is soluble when expressed in E. coli. An important goal has been to determine how the soluble VP14 protein is targeted to epoxy-carotenoid substrates that are located in the thylakoid and envelope membranes of chloroplasts and other plastids. Using an in vitro chloroplast import assay, we have shown that VP14 is imported into chloroplasts with cleavage of a short stroma-targeting domain. The mature VP14 exists in two forms, one which is soluble in stroma and the other bound to thylakoid membranes. Analysis of a series of truncated VP14 mutants mapped the membrane targeting signal to the 160 amino acid N-terminal sequence. A putative amphipathic alpha-helix within this region is essential, but not sufficient, for the membrane targeting. Either deletion of or insertion of helix breaking residues into this region abolished the membrane binding, whereas a chimeric protein carrying just the amphipathic region fused with bacterial glutathione S-transferase failed to associate with the thylakoid membrane. The membrane-bound VP14 was partially resistant to chaotropic washes such as 0.1 M Na2CO3 (pH 11.5) and 6 M urea. Unlabelled recombinant VP14 inhibited the tight binding of imported VP14, suggesting that VP14 is associated with specific components of the thylakoid membrane.

Causes of childhood blindness in Malaysia: results from a national study of blind school students.

A national study was conducted in children attending six schools for the blind in Malaysia to identify the anatomical site and underlying causes of blindness (BL) and severe visual impairment (SVI), with a view to determine the potentially preventable and treatable causes so that appropriate control measures can be implemented in the future. The standardized clinical examination of eyes was performed and the findings were recorded on the WHO Prevention of Blindness Programme eye examination record form for children with blindness and low vision. A total of 358 children aged between 7 and 17 years were examined, of whom 332 (92.7%) were blind or severely visually impaired. The results relate to these 332 children. Lens was the major anatomical site (22.3%) of visual loss followed by retina (20.8%), whole globe (17.2%), cornea (15.1%), optic nerve (8.7%) and uvea (5.1%). Glaucoma was responsible for BL/SVI in 7.2% and others in 3.6% of cases. Hereditary diseases were responsible for visual loss in 29.5%, intrauterine factors in 4.5%, perinatal factors in 9% and childhood factors in 7.8% of cases. However, the aetiology was unknown in 49.1% of cases which included congenital anomalies of the globe. Childhood cataract and corneal scarring are major treatable causes of BL/SVI that can benefit from future intervention strategies. Perinatal screening for intrauterine factors and hereditary eye diseases, and appropriate interventional therapy will help in reducing the prevalence of childhood blindness.

Genetic control of abscisic acid biosynthesis in maize.

Abscisic acid (ABA), an apocarotenoid synthesized from cleavage of carotenoids, regulates seed maturation and stress responses in plants. The viviparous seed mutants of maize identify genes involved in synthesis and perception of ABA. Two alleles of a new mutant, viviparous14 (vp14), were identified by transposon mutagenesis. Mutant embryos had normal sensitivity to ABA, and detached leaves of mutant seedlings showed markedly higher rates of water loss than those of wild type. The ABA content of developing mutant embryos was 70% lower than that of wild type, indicating a defect in ABA biosynthesis. vp14 embryos were not deficient in epoxy-carotenoids, and extracts of vp14 embryos efficiently converted the carotenoid cleavage product, xanthoxin, to ABA, suggesting a lesion in the cleavage reaction. vp14 was cloned by transposon tagging. The VP14 protein sequence is similar to bacterial lignostilbene dioxygenases (LSD). LSD catalyzes a double-bond cleavage reaction that is closely analogous to the carotenoid cleavage reaction of ABA biosynthesis. Southern blots indicated a family of four to six related genes in maize. The Vp14 mRNA is expressed in embryos and roots and is strongly induced in leaves by water stress. A family of Vp14-related genes evidently controls the first committed step of ABA biosynthesis. These genes are likely to play a key role in the developmental and environmental control of ABA synthesis in plants.

Specific oxidative cleavage of carotenoids by VP14 of maize.

The plant growth regulator abscisic acid (ABA) is formed by the oxidative cleavage of an epoxy-carotenoid. The synthesis of other apocarotenoids, such as vitamin A in animals, may occur by a similar mechanism. In ABA biosynthesis, oxidative cleavage is the first committed reaction and is believed to be the key regulatory step. A new ABA-deficient mutant of maize has been identified and the corresponding gene, Vp14, has been cloned. The recombinant VP14 protein catalyzes the cleavage of 9-cis-epoxy-carotenoids to form C25 apo-aldehydes and xanthoxin, a precursor of ABA in higher plants.

Patient profile and survival in 270 computer tomography-staged patients with nasopharyngeal cancer treated at the Singapore General Hospital.

This is a report analysing the patient profile and survival results in 270 patients with nasopharyngeal carcinoma treated with radiation therapy between July 1987 and December 1988. The patients had a median age of 52.6 months, and a male-female ratio of 2.5:1. Ninety-four percent of patients were Chinese. The commonest presentation was that of a neck mass (found in approximately 65% of patients). Approximately two-thirds presented with disease more advanced than Ho's stage II. At a median follow-up of 52.6 months, the 5-year actuarial survival rate was 53% and the freedom from relapse rate was 57%. One hundred and seven patients died within the observation period. Of these, 46 patients had disease in the post nasal space, 41 in the neck and 60 in sites outside the head and neck.

Voltage-current relationship for flashlamps: an empirical approach.

This paper presents the results of an empirical study of the voltage-current relationship of flashlamps. It is shown that the Goncz and Marotta relationships are limited in that they can only be used in certain current density regimes. Based on empirical data, a generalized empirical voltage-current relationship is proposed. In particular, the generalized form is found to be a voltage-current relationship with a power factor. This power factor is found to be a function of the current density of the flashlamp. The relationships used in the past are found to fit this generalized form according to their respective current density regimes.

Subtractive Moire technique for evaluating the wedge angle of a beam splitter.

This Technical Note describes a method to measure the wedge angle of a beam splitter that relies on shear interferometry and the moire phenomenon.

Lung cancer metastases--management.

Distant metastases from lung cancer is a common occurrence in a common malignancy. Almost every organ may be involved but the extra-thoracic sites posing common clinical problems are brain metastases, cord compression, painful bone metastases or pathological fractures, nodal spread and liver involvement. A review of the records of 225 lung cancer patients referred to the Therapeutic Radiology Department, Singapore General Hospital, during the calender year 1985 showed a metastatic rate of 13.8% at referral. On subsequent follow up, an additional 49 patients (21.7%) developed metastases clinically. The organs involved were bone (21 patients), spinal cord (21 patients), brain (18 patients), liver (13 patients), other lung (7 patients) and other sites (17 patients). The management of metastases to the brain, bone and liver, and spinal cord compression will be discussed.

Conservation breast treatment: a viable option locally.

Conservation treatment in carcinoma of the breast is a viable option in the West but is still an uncommon practice locally. Many reasons have been put forth, including the late stage of the tumour we see and the small breast size. This paper presents 25 cases treated by lumpectomy and irradiation with satisfactory cosmetic results, although the follow-up period is short. The introduction of this technique may encourage women to seek treatment earlier, without the fear of losing their breasts.