Plastic pellets make Excirolana armata more aggressive: Intraspecific interactions and isopod mortality differences between populations

Plastic pellets represent a significant component of microplastic (< 5 mm) pollution. Impacts caused by plastic pellets involve physical harm and toxicity related to ingestion and non-ingestion (such as the release of chemicals in leachates). The latter is the main route of exposure for invertebrate macrobenthic populations. This study aimed to compare the toxicity of plastic pellets in distinct marine macrobenthic populations, considering the influence of sediment characteristics (organic matter and grain size) and quality (contamination by hydrophobic chemicals) on ecotoxicological effects, as well as the influence of color on the toxicity of beach-stranded plastic pellets. We performed three experiments on plastic pellet exposure using Excirolana armata from beaches with high and low pellet density. When exposed to pellets, populations that inhabit beaches without pellets demonstrate higher mortality than those inhabiting beaches with high pellet densities. The mortality of E. armata to pellets was higher when the exposure occurred in sediment with high organic matter (OM), suggesting that chemicals were transferred from pellets to OM. Yellowish beach-stranded pellets induced higher mortality of E. armata than the white tones did. We also observed lethargic (near-dead) and dead individuals being preyed upon by healthy individuals, a cannibalistic behavior that raises an ecological concern regarding the negative effects of this exposure on intraspecific interactions in marine macrobenthic populations.

Utilizing distinct CAR and TCR signaling to generate enhanced cellular immunotherapy

CAR-T cells utilize TCR signaling cascades and the recognition functions of antibodies. CAR-T technology has achieved significant success in treatment of certain, primarily liquid, cancers. Nonetheless, many challenges hinder the development of this therapy, for example the efficacy for solid tumors. These challenges show our inadequate understanding of this technology, particularly regarding CAR signaling, and how it may differ from TCR signaling. To dissect CAR signaling, CAR and TCR targeting the same antigen were compared directly. This comparison revealed that CAR was sufficient to bind monomeric antigens due to its high affinity but required oligomeric antigens for its activation. CAR sustained the transduced signal significantly longer than did TCR. CD8 coreceptor was recruited to the CAR synapse but played a negligible role in signaling, unlike for TCR signaling. Surprisingly, we identified a non-canonical CAR signaling triggered in the absence of SRC family kinase (SFK) LCK, which is essential for TCR signaling. We show that LCK-deficient CAR-T cells are strongly signaled through CAR and have a better in vivo efficacy because of reduced exhaustion phenotype and enhanced induction of memory. This non-canonical signaling of CAR-T cells provides new insight into the initiation of TCR and CAR signaling as well as important clinical implications for improvement of CAR function.

Supported by grants from Singapore Ministry of Health’s National Medical Research Council: OFIRG19nov-0066; and Ministry of Education, NUHSRO/2020/110/T1/SEED-MAR/06, and NUS ILO TAP Grant: TAP2002019-04-25. LW, QW and JL were supported by research scholarships from Yong Loo Lin School of Medicine.

Patterns of middle-ear cholesteatoma and implications for surgical approach

OBJECTIVES

Understanding the pattern of middle-ear cholesteatoma becomes pertinent with the rise of endoscopic surgery as surgeons decide on the optimal approach to visualise and extirpate disease. With modifications to the Telmesani attic-tympanum-mastoid staging system, this study aimed to evaluate the commonest patterns of middle-ear cholesteatoma and their implications for surgical approach.

METHODS

A retrospective study was conducted in a single tertiary institution in Singapore. All patients undergoing cholesteatoma surgery between January 2012 and June 2015 were included. Staging of cholesteatoma was based on clinical assessment corroborated by radiological findings.

RESULTS

Out of the 55 ears included, 98.2 per cent had cholesteatoma involving the attic. The disease extended into the mastoid antrum and beyond in 43 cases (78.2 per cent). The facial recess and/or sinus tympanum was affected in 26 cases (47.3 per cent).

CONCLUSION

The majority of cholesteatoma cases present with extensive attic disease and significant mastoid involvement. In these cases, endoscopes may be best suited to adjunctive rather than exclusive use in surgery.

MR Imaging Criteria for the Detection of Nasopharyngeal Carcinoma: Discrimination of Early-Stage Primary Tumors from Benign Hyperplasia

BACKGROUND AND PURPOSE

MR imaging can detect nasopharyngeal carcinoma that is hidden from endoscopic view, but for accurate detection carcinoma confined within the nasopharynx (stage T1) must be distinguished from benign hyperplasia of the nasopharynx. This study aimed to document the MR imaging features of stage T1 nasopharyngeal carcinoma and to attempt to identify features distinguishing it from benign hyperplasia.

MATERIALS AND METHODS

MR images of 189 patients with nasopharyngeal carcinoma confined to the nasopharynx and those of 144 patients with benign hyperplasia were reviewed and compared in this retrospective study. The center, volume, size asymmetry (maximum percentage difference in area between the right and left nasopharyngeal halves), signal intensity asymmetry, deep mucosal white line (greater contrast enhancement along the deep tumor margin), and absence/distortion of the adenoidal septa were evaluated. Differences were assessed with logistic regression and the χ² test.

RESULTS

The nasopharyngeal carcinoma center was lateral, central, or diffuse in 134/189 (70.9%), 25/189 (13.2%), and 30/189 (15.9%) cases, respectively. Nasopharyngeal carcinomas involving the walls showed that a deep mucosal white line was present in 180/183 (98.4%), with a focal loss of this line in 153/180 (85%) cases. Adenoidal septa were absent or distorted in 111/111 (100%) nasopharyngeal carcinomas involving the adenoid. Compared with benign hyperplasia, nasopharyngeal carcinoma had a significantly greater volume, size asymmetry, signal asymmetry, focal loss of the deep mucosal white line, and absence/distortion of the adenoidal septa (P < .001). Although size asymmetry was the most accurate criterion (89.5%) for nasopharyngeal carcinoma detection, use of this parameter alone would have missed 11.9% of early-stage T1 nasopharyngeal carcinomas.

CONCLUSIONS

MR imaging features can help distinguish stage T1 nasopharyngeal carcinoma from benign hyperplasia in most cases.

Micro-textured films for reducing microbial colonization in a clinical setting

BACKGROUND

Transmission of microbes in the hospital environment occurs frequently through human interactions with high-touch surfaces such as patient beds and over-bed tables. Although stringent cleaning routines are implemented as a preventive measure to minimize transmission of microbes, it is desirable to have high-touch surfaces made of antimicrobial materials. Physical texturing of solid surfaces offers a non-bactericidal approach to control the colonization of such surfaces by microbes.

AIM

To investigate the efficacy of micro-textured polycarbonate films in reducing bacterial load on over-bed tables in a hospital ward.

METHODS

Two different micro-patterns were fabricated on polycarbonate film via a thermal imprinting method. Micro-textured films were then mounted on patient over-bed tables in a general hospital ward and the bacterial load monitored over 24 h. Total colony counts, which represented on-specific bacterial loading, and meticillin-resistant Staphylococcus aureus counts were monitored at each time-point.

FINDINGS

Over a period of 24 h, both micro-textured surfaces showed consistently lower bacterial load as compared to the unpatterned polycarbonate and the bare over-bed table laminate. This study supports the findings of earlier laboratory-scale studies that microscale physical texturing can reduce bacterial colonization on a solid surface.

CONCLUSION

Results of the current study suggest that micro-textured surfaces could provide a viable method for reducing microbial contamination of high-touch surfaces in hospitals.

Do we need transbronchial lung biopsy if we have bronchoalveolar lavage Xpert® MTB/RIF?

BACKGROUND

Studies evaluating the role of transbronchial lung biopsy (TBLB) in diagnosing pulmonary tuberculosis (PTB) date back decades and have shaped current practice. However, with the recent advent of bronchoalveolar lavage (BAL) Xpert® MTB/RIF, it is time to re-evaluate the role of TBLB.

OBJECTIVE

To assess the impact of BAL and TBLB with the addition of BAL Xpert on diagnostic PTB yields and time to treatment initiation in sputum-scarce or acid-fast bacilli (AFB) smear-negative PTB patients.

METHODS

We retrospectively reviewed all sputum-scarce or AFB smear-negative patients who underwent both BAL and TBLB for suspected PTB between March 2011 and October 2013. Xpert was performed on all BAL specimens.

RESULTS

Of 158 patients included in our analysis, 44 were culture-proven PTB. Ninety-four per cent of the patients had AFB smear-negative BAL samples. The sensitivity and specificity of Xpert in AFB smear-negative BAL samples were respectively 60% and 98%. The addition of BAL Xpert expedited the institution of PTB treatment while having diagnostic yields comparable to those of conventional BAL with TBLB.

CONCLUSIONS

The use of BAL Xpert may obviate the need for TBLB in increasing the diagnostic yield of PTB in sputum-scarce or AFB smear-negative patients.

Results from the Survey of Antibiotic Resistance (SOAR) 2012-14 in Thailand, India, South Korea and Singapore

OBJECTIVES

To provide susceptibility data for community-acquired respiratory tract isolates of Streptococcus pneumoniae, Streptococcus pyogenes, Haemophilus influenzae and Moraxella catarrhalis collected in 2012-14 from four Asian countries.

METHODS

MICs were determined using Etest(®) for all antibiotics except erythromycin, which was evaluated by disc diffusion. Susceptibility was assessed using CLSI, EUCAST and pharmacokinetic/pharmacodynamic (PK/PD) breakpoints. For macrolide/clindamycin interpretation, breakpoints were adjusted for incubation in CO2 where available.

RESULTS

Susceptibility of S. pneumoniae was generally lower in South Korea than in other countries. Penicillin susceptibility assessed using CLSI oral or EUCAST breakpoints ranged from 21.2% in South Korea to 63.8% in Singapore. In contrast, susceptibility using CLSI intravenous breakpoints was much higher, at 79% in South Korea and ∼95% or higher elsewhere. Macrolide susceptibility was ∼20% in South Korea and ∼50%-60% elsewhere. Among S. pyogenes isolates (India only), erythromycin susceptibility (∼20%) was lowest of the antibiotics tested. In H. influenzae antibiotic susceptibility was high except for ampicillin, where susceptibility ranged from 16.7% in South Korea to 91.1% in India. South Korea also had a high percentage (18.1%) of β-lactamase-negative ampicillin-resistant isolates. Amoxicillin/clavulanic acid susceptibility for each pathogen (PK/PD high dose) was between 93% and 100% in all countries except for H. influenzae in South Korea (62.5%).

CONCLUSIONS

Use of EUCAST versus CLSI breakpoints had profound differences for cefaclor, cefuroxime and ofloxacin, with EUCAST showing lower susceptibility. There was considerable variability in susceptibility among countries in the same region. Thus, continued surveillance is necessary to track future changes in antibiotic resistance.

Sinonasal angioleiomyoma

BACKGROUND

Angioleiomyoma of the nasal cavity is an extremely rare benign neoplasm. It usually occurs in the lower extremities. Up to date, only few cases of angioleiomyoma have been reported. First case of angioleiomyoma of nasal cavity was reported in 1966. We report a rare case of angioleiomyoma arising from the right maxillary sinus.

CASE REPORT

A 43-year-old lady presented with recurrent epistaxis and right nasal obstruction for two months duration. Clinical examination revealed a huge right nasal mass obstructing the right nasal cavity. The tumour was excised completely via endoscopic endonasal surgical approach. Histopathological examination confirmed the tumour is sinonasal angioleiomyoma. Postoperatively, she recovered well without any recurrence after a year of followup.

CONCLUSION

This tumour has an excellent prognosis and recurrence is extremely rare if excised completely.

Superior cervical ganglion mimicking retropharyngeal adenopathy in head and neck cancer patients: MRI features with anatomic, histologic, and surgical correlation

INTRODUCTION

To describe the unique MRI findings of superior cervical ganglia (SCG) that may help differentiate them from retropharyngeal lymph nodes (RPLNs).

METHODS

A retrospective review of post-treatment NPC patients from 1999 to 2012 identified three patients previously irradiated for NPC that were suspected of having recurrent nodal disease in retropharyngeal lymph nodes during surveillance MRI. Subsequent surgical exploration revealed enlarged SCG only; no retropharyngeal nodal disease was found. A cadaveric head specimen was also imaged with a 3T MRI before and after dissection. In addition, SCG were also harvested from three cadaveric specimens and subjected to histologic analysis.

RESULTS

The SCG were found at the level of the C2 vertebral body, medial to the ICA. They were ovoid on axial images and fusiform and elongated with tapered margins in the coronal plane. T2-weighted (T2W) signal was hyperintense. No central elevated T1-weighted (T1W) signal was seen within the ganglia in non-fat-saturated sequences to suggest the presence of a fatty hilum. Enhancement after gadolinium was present. A central "black dot" was seen on axial T2W and post-contrast images in two of the three SCG demonstrated. Histology showed the central black line was comprised of venules and interlacing neurites within the central portion of the ganglion.

CONCLUSIONS

The SCG can be mistaken for enlarged RPLNs in post-treatment NPC patients. However, there are features which can help differentiate them from RPLNs, preventing unnecessary therapy. These imaging findings have not been previously described.

Delineation of clinical features in Wiedemann-Steiner syndrome caused by KMT2A mutations

Wiedemann-Steiner syndrome (WSS) is an autosomal dominant congenital anomaly syndrome characterized by hairy elbows, dysmorphic facial appearances (hypertelorism, thick eyebrows, downslanted and vertically narrow palpebral fissures), pre- and post-natal growth deficiency, and psychomotor delay. WSS is caused by heterozygous mutations in KMT2A (also known as MLL), a gene encoding a histone methyltransferase. Here, we identify six novel KMT2A mutations in six WSS patients, with four mutations occurring de novo. Interestingly, some of the patients were initially diagnosed with atypical Kabuki syndrome, which is caused by mutations in KMT2D or KDM6A, genes also involved in histone methylation. KMT2A mutations and clinical features are summarized in our six patients together with eight previously reported patients. Furthermore, clinical comparison of the two syndromes is discussed in detail.

Female ageing and reproductive outcome in assisted reproduction cycles

INTRODUCTION

Fertility in women declines with increasing age. With the deferment of marriage and childbearing, couples are turning to assisted reproductive technology to counteract this decline. We aimed to evaluate the results of in vitrofertilisation (IVF)/intracytoplasmic sperm injection (ICSI) in women of different age groups, and highlight the cost-effectiveness of IVF treatment in these groups while assessing its implications on the national healthcare provision model.

METHODS

Retrospective analysis of 3,412 stimulated IVF/ICSI cycles in a hospital-based IVF centre was performed from January 2008 to December 2010. Patients were stratified into seven age groups: < 30 years; 30-35 years; 36-37 years; 38 years; 39 years; 40-44 years; and ≥ 45 years.

RESULTS

Age had a significant effect on the number of cycles leading to embryo transfer (p < 0.001). The number of oocytes retrieved decreased across the various age groups (p < 0.001) and was the highest among women aged < 30 (mean 18.5 ± 10.3) years. With increasing age, there was a trend toward a lower fertilisation rate. Age also had a significant effect on the rates of clinical pregnancy, live birth and multiple pregnancies (p < 0.001).

CONCLUSION

Patients aged < 30 years had the best IVF outcomes, reflecting optimal reproductive capacity. Age-related decline in fertility starts after 30 years. Women opting for IVF should be counselled about age-specific success rates while taking into account individual risk factors.

Diagnosing features of Jacobson's nerve schwannoma

Jacobson's nerve schwannoma is a rare middle ear tumour presenting as a mass along the cochlear promontory. It can be differentiated from other masses along the promontory based on clinical findings, and computed tomography and magnetic resonance imaging features. For small-sized masses, it is possible to differentiate the various middle ear schwannomas from one another. We present the case of a 40-year-old woman with a ten-year history of left hearing loss who was diagnosed with Jacobson's nerve schwannoma.

Epidemiology of invasive fungal diseases among patients with haematological disorders in the Asia-Pacific: a prospective observational study

We conducted a 2-year multicentre prospective observational study to determine the epidemiology of and mortality associated with invasive fungal diseases (IFDs) among patients with haematological disorders in Asia. Eleven institutions from 8 countries/regions participated, with 412 subjects (28.2% possible, 38.3% probable and 33.5% proven IFDs) recruited. The epidemiology of IFDs in participating institutions was similar to Western centres, with Aspergillus spp. (65.9%) or Candida spp. (26.7%) causing the majority of probable and proven IFDs. The overall 30-day mortality was 22.1%. Progressive haematological disorder (odds ratio [OR] 5.192), invasive candidiasis (OR 3.679), and chronic renal disease (OR 6.677) were independently associated with mortality.

Kimura's Disease: Diagnostic Challenge and Treatment Modalities

CASE REPORT

Five cases of Kimura's disease had been treated in our centre from year 2003 to 2010. All cases were presented with head and neck mass with cervical lymphadenopathy. Surgical excision was performed for all cases. Definite diagnosis was made by histopathological examination of the resected specimens. One out of five cases developed tumour recurrence four years after resection.

CONCLUSION

Surgical excision is our choice of treatment because the outcome is immediate and definite tissue diagnosis is feasible after resection. Oral corticosteroid could be considered as an option in advanced disease. However, tumour recurrence is common after cessation of steroid therapy.

Genotype and clinical care correlations in craniosynostosis: findings from a cohort of 630 Australian and New Zealand patients

Craniosynostosis is one of the most common craniofacial disorders encountered in clinical genetics practice, with an overall incidence of 1 in 2,500. Between 30% and 70% of syndromic craniosynostoses are caused by mutations in hotspots in the fibroblast growth factor receptor (FGFR) genes or in the TWIST1 gene with the difference in detection rates likely to be related to different study populations within craniofacial centers. Here we present results from molecular testing of an Australia and New Zealand cohort of 630 individuals with a diagnosis of craniosynostosis. Data were obtained by Sanger sequencing of FGFR1, FGFR2, and FGFR3 hotspot exons and the TWIST1 gene, as well as copy number detection of TWIST1. Of the 630 probands, there were 231 who had one of 80 distinct mutations (36%). Among the 80 mutations, 17 novel sequence variants were detected in three of the four genes screened. In addition to the proband cohort there were 96 individuals who underwent predictive or prenatal testing as part of family studies. Dysmorphic features consistent with the known FGFR1-3/TWIST1-associated syndromes were predictive for mutation detection. We also show a statistically significant association between splice site mutations in FGFR2 and a clinical diagnosis of Pfeiffer syndrome, more severe clinical phenotypes associated with FGFR2 exon 10 versus exon 8 mutations, and more frequent surgical procedures in the presence of a pathogenic mutation. Targeting gene hot spot areas for mutation analysis is a useful strategy to maximize the success of molecular diagnosis for individuals with craniosynostosis.

Biallelic DICER1 mutations occur in Wilms tumours

DICER1 is an endoribonuclease central to the generation of microRNAs (miRNAs) and short interfering RNAs (siRNAs). Germline mutations in DICER1 have been associated with a pleiotropic tumour predisposition syndrome and Wilms tumour (WT) is a rare manifestation of this syndrome. Three WTs, each in a child with a deleterious germline DICER1 mutation, were screened for somatic DICER1 mutations and were found to bear specific mutations in either the RNase IIIa (n = 1) or the RNase IIIb domain (n = 2). In the two latter cases, we demonstrate that the germline and somatic DICER1 mutations were in trans, suggesting that the two-hit hypothesis of tumour formation applies for these examples of WT. Among 191 apparently sporadic WTs, we identified five different missense or deletion somatic DICER1 mutations (2.6%) in four individual WTs; one tumour had two very likely deleterious somatic mutations in trans in the RNase IIIb domain (c.5438A>G and c.5452G>A). In vitro studies of two somatic single-base substitutions (c.5429A>G and c.5438A>G) demonstrated exon 25 skipping from the transcript, a phenomenon not previously reported in DICER1. Further we show that DICER1 transcripts lacking exon 25 can be translated in vitro. This study has demonstrated that a subset of WTs exhibits two 'hits' in DICER1, suggesting that these mutations could be key events in the pathogenesis of these tumours.

Primary lacrimal sac lymphoma with recurrence: a case report

Primary lacrimal sac lymphoma is rare. The common clinical features are epiphora and medial canthal swelling which mimic nasolacrimal duct obstruction. Histological examination is therefore important to avoid delay in diagnosis and treatment. We report a case of primary lacrimal sac lymphoma in a 72-year-old female who developed a metachronous tumour at the hard palate one year after excision of the lacrimal sac tumour.

Review of congenital inner ear abnormalities on CT temporal bone

The aetiology of profound hearing loss in children is complex and multifactorial. Congenital inner ear abnormality is a major cause of hearing loss in children. CT temporal bone imaging is the modality of choice in the investigation of hearing loss. Recognising the congenital abnormalities of the inner ear guides the clinician's management of the condition. This pictorial essay illustrates the congenital abnormalities of the inner ear on high resolution CT temporal bone images and correlation with developmental arrest during embryology.

Head and neck cancer: possible causes for delay in diagnosis and treatment

OBJECTIVE

To explore the possible causes for delay in diagnosis and treatment of head and neck cancer at Sarawak General Hospital (SGH).

STUDY DESIGN

This is a prospective study of time interval between onset of symptom, first medical consultation, first specialist clinic consultation, diagnosis and treatment of head and neck cancer in otorhinolaryngology head and neck (ORL-HNS) and dental clinics at Sarawak General Hospital. Forty-two consecutive cases diagnosed to have cancer between July to December 2006 were studied.

RESULTS

Mean interval between onset of symptom and medical consultation was 3.8 months, mean interval between first medical consultation to ORL-HNS or dental clinic referral was 8.4 weeks, mean duration between first ORL-HNS or dental specialist consultation to histopathological diagnosis was 18.8 days while duration between diagnosis to definite treatment was 26.9 days.

CONCLUSION

Most cases were diagnosed at advanced stage. Patient delay was the main problem. There was significant delay by frontier health workers in identifying sinister symptoms of malignancy. Timing for diagnosis and treatment after specialist referral were comparable with other published studies.

CT features of parotid gland oncocytomas: a study of 10 cases and literature review

Oncocytomas of the salivary glands are rare benign epithelial tumors which occur most commonly in the parotid gland. The aim of our study was to characterize the clinical-radiologic-pathologic spectrum of parotid oncocytomas in a series of 10 cases seen in our institution between January 2003 and November 2008. The CT features of parotid oncocytomas in the largest imaging series of this rare but important benign lesion include a well-defined enhancing tumor with a "deformable" appearance when large, and a non-enhancing curvilinear cleft or cystic component. These CT findings are potentially helpful in distinguishing these benign lesions from other parotid tumors in clinical scenarios that preclude surgical resection or when biopsy results are non-diagnostic. Further studies are advocated to validate the specificity and positive predictive value of these imaging features.

Imaging characteristics of schwannoma of the cervical sympathetic chain: a review of 12 cases

BACKGROUND AND PURPOSE

SCSCs are rare. This study reviews our experience with CT and MR imaging of SCSCs.

MATERIALS AND METHODS

We retrospectively reviewed the CT and MR imaging studies as well as clinical data of 12 patients (6 men, 6 women; mean age, 41 years; range, 27-55 years) with surgicopathologic evidence of SCSC, referred to our institution between January 1999 to October 2008. Images were evaluated with respect to the location, number, morphology, attenuation/signal intensity, enhancement characteristics, and patterns of mass effect of the schwannomas.

RESULTS

The schwannomas were solitary, well-circumscribed, and medial to the carotid sheath. Seven were hypoattenuated to skeletal muscle on CT with poor postcontrast enhancement, 4 were isoattenuated, and a single lesion showed intense heterogeneous enhancement. At MR imaging, they were heterogeneously bright on T2WI with intense inhomogeneous postgadolinium enhancement. The ICA was displaced anteriorly in 9 patients with a component of lateral displacement in 8 of these patients. The ICA was in a neutral position in 2 patients and posterolaterally displaced in 1 patient. A single patient demonstrated separation of the ICA and IJV. There was splaying of the carotid bifurcation in 4 patients.

CONCLUSIONS

We present the patterns of mass effect and the spectrum of CT and MR imaging characteristics of SCSC, including certain observations that are infrequently described in the published literature.

Hypertensive retinopathy and sensorineural hearing loss

OBJECTIVE

To determine the correlation between hypertensive retinopathy (which is the end-organ damage of the vessels due to chronic hypertension) with sensorineural hearing loss.

METHODS

Pure tone hearing threshold of 56 hypertensive patients were compared with 56 normal age and sex matched control. Comparisons of pure tone hearing threshold are made among different group (grade) of hypertensive retinopathy patients and control (non-hypertensive patients).

RESULTS

The mean hearing thresholds were higher (worse) in all the frequencies on both sides in the hypertensive study group compared with normal subjects. However it was found to be statistically significant when tested using independent sample test (p < 0.05) on right ear at 2,000 Hz, 4,000 Hz and 8,000 Hz only. The mean hearing threshold is higher in all frequencies in the presence of retinopathy compared to control. However, the difference was found to be only statistically significant in the mean hearing threshold between grade I and control at 4,000 Hz and 8,000 Hz on both sides and at 1,000 Hz and 2,000 Hz on right ear. Hypertensive patient with grade I retinopathy had higher pure tone hearing thresholds at 4,000 Hz and 8,000 Hz compared to hypertensive without retinopathy and normal control.

CONCLUSIONS

Hypertensive retinopathy appears to be associated with high frequency sensor neural hearing loss.

Endoscopic nasopharyngectomy: the Sarawak experience

Shifting the paradigm of treatment of a locally recurrent nasopharyngeal carcinoma (NPC) from the non-surgical management to a surgical modality has always been a challenge. However, many studies on endoscopic nasopharyngectomy have proven it to be a reliable form of treatment with an excellent outcome. Since 2007, in Sarawak General Hospital, six cases of endoscopic nasopharyngectomy for locally recurrent NPC have been performed with encouraging results.

Long-range regulation at the SOX9 locus in development and disease

The involvement of SOX9 in congenital skeletal malformation was demonstrated 15 years ago with the identification of mutations in and around the gene in patients with campomelic dysplasia (CD). Translocations upstream of the coding sequence suggested that altered expression of SOX9 was capable of severely impacting on skeletal development. Subsequent studies in humans and animal models pointed towards a complex regulatory region controlling SOX9 transcription, involving approximately 1 Mb of upstream sequence. Recent data indicate that this regulatory domain may extend substantially further, with identification of several disruptions greater than 1 Mb upstream of SOX9 associated with isolated Pierre Robin sequence (PRS), a craniofacial disorder that is frequently a component of CD. The translocation breakpoints upstream of SOX9 can now be clustered into three groups, with a trend towards less severe skeletal phenotypes as the distance of each cluster from SOX9 increases. In this review we discuss how the identification of novel lesions surrounding SOX9 support the existence of tissue specific enhancers acting over a large distance to regulate expression of the gene during craniofacial development, and we highlight the potential for discovery of additional regulatory elements within the extended SOX9 control region.

Prenatal diagnosis of cri-du-chat syndrome: importance of ultrasonographical markers

Cri-du-chat syndrome is a chromosomal abnormality involving a 5p deletion and is characterised by a cat-like cry, mental retardation, microcephaly and abnormal facial features. We report a case of prenatally-diagnosed cri-du-chat syndrome. Although PAPP-A was low at first trimester screening (FTS), the combined risks of trisomies 21, 18 and 13 were low. Amniocentesis was, however, carried out following the ultrasonographical observation of a severely hypoplastic nasal bone, cerebellar hypoplasia, choroid plexus cyst and a single umbilical artery during the second trimester. This case report highlights the importance of careful examination of basic and extended foetal biometry and structures, as well as soft markers for the detection of rarer chromosomal abnormalities that may be missed at FTS.

Reducing antimicrobial resistance through appropriate antibiotic usage in Singapore

Two alarming trends threaten the future utility of antimicrobial agents: rise of antimicrobial resistance and decline in development of new antibiotics. The continuing emergence and spread of antimicrobial-resistant microbes--a global public health issue--exacerbates the problem of paucity of new antimicrobial agents. Singapore's public sector hospitals currently have some of the highest rates of antimicrobial resistance worldwide, evolving with surprising speed over the past two decades. Because there was no systematic surveillance until fairly recently, this healthcare problem has not been emphasised. In contrast, it is difficult to assess the scale of antimicrobial resistance in the community in view of the lack of recent research, although indirect evidence suggests that this is also a source of concern. A panel comprising representatives from multiple professional healthcare societies was convened to address the issue of antimicrobial resistance in Singapore, focusing on the conservation of antibiotics against resistance. From a review of the medical literature, potentially successful strategies involve facilitating prudent and appropriate use of antimicrobial agents in tandem with other interventions in infection control. Presently, there is a lack of data on the appropriate use of antibiotics in Singapore. The recommendations of the panel are: The professions should look into ways and means to support systematic data collection on antibiotic use and appropriateness of use; The Ministry of Health should take a more active and positive role in regulating antibiotic usage; Hospitals should actively support effective antimicrobial stewardship programmes; Educators should coordinate programmes to give greater emphasis on appropriate antimicrobial prescription, and support good clinical practice; and, Local and regional branches of pharmaceutical companies should adopt the Pharmaceutical Research and Manufacturers of America's updated code of conduct on interactions with physicians as a step towards re-aligning the industry-physician relationship in the direction of educational and informational support.

Detection of plasmid-mediated AmpC in Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis

AIMS

This study investigated the prevalence of plasmid-mediated AmpC production in selected clinical isolates of Escherichia coli, Klebsiella species and Proteus mirabilis, and compared the results of boronic acid disc screening with conventional susceptibility testing for the detection of AmpC-positive isolates.

METHODS

E coli, Klebsiella species and P mirabilis with reduced susceptibility to amoxycillin-clavulanate, cefuroxime and cephalexin, but without phenotypic evidence of extended-spectrum beta-lactamases were screened for AmpC activity using enzyme-extraction methods. The presence of plasmid-mediated ampC was determined by multiplex PCR. Antibiotic susceptibilities were determined using both disc and dilution-based methods. A disc-based screening method for detection of AmpC-producing strains was evaluated using boronic acid as an inhibitor of AmpC, and cefoxitin as the antibiotic substrate.

RESULTS

Plasmid-mediated ampC was present in 26% of study isolates, with CMY-like enzymes detected predominantly in E coli and DHA-like enzymes predominantly in Klebsiella pneumoniae. Current susceptibility methods failed to detect a significant proportion of plasmid-mediated AmpC-producing isolates, with 33% of such strains interpreted as susceptible to third-generation cephalosporins using current Clinical Laboratory Standards Institute breakpoints. The boronic acid disc method showed sensitivity and specificity of 90% and 98% respectively in detecting AmpC-positive isolates.

CONCLUSION

The prevalence of plasmid-mediated ampC was high in the study population, and may be missed by conventional susceptibility testing methods. Inhibitor-based screening methods would improve detection of this emerging resistance phenotype.

Evaluation of disc susceptibility tests performed directly from positive blood cultures

AIMS

To evaluate the accuracy of direct disc susceptibility testing performed from positive BACTEC blood culture vials, using a predetermined dilution protocol.

METHODS

Direct susceptibility testing was performed from 432 positive blood culture vials, generating 3829 antibiotic-organism results. Results were compared with those obtained by standard disc susceptibility testing according to Clinical Laboratory Standards Institute (CLSI) methods.

RESULTS

When results were compared with the reference method, no very major errors were detected. One (0.03%) major error and 89 (2.3%) minor errors were found. Error rates by organism group ranged from 1.3% for Pseudomonas aeruginosa to 8.2% for beta-haemolytic streptococci.

CONCLUSIONS

Direct susceptibility testing provided accurate susceptibility results for most organism-antibiotic combinations, with the exception of the beta-haemolytic streptococci.

Comparison of Etest, Vitek and agar dilution for susceptibility testing of colistin

In total, 172 isolates of Enterobacteriaceae, Acinetobacter spp., Pseudomonas aeruginosa and Stenotrophomonas maltophilia were tested for susceptibility to colistin by agar dilution, Etest and the Vitek 2 system. Isolates with a colistin MIC < or =2 mg/L were considered to be susceptible. Fifty-four (31%) Gram-negative isolates were resistant to colistin. Categorical agreement between agar dilution and Etest was 87%, and between agar dilution and Vitek 2 was 82%. Based on the data obtained, the Vitek 2 system was unreliable for detecting colistin resistance, and results obtained by Etest may require confirmation by a standard MIC susceptibility testing method.

First-line gemcitabine and carboplatin in advanced ovarian carcinoma: a phase II study

OBJECTIVES

To evaluate tumour response rate and toxicities of gemcitabine and carboplatin in chemonaive subjects with advanced epithelial ovarian cancer.

DESIGN

A phase II study.

SETTING

Gynaecologic oncologic unit.

POPULATION

Twenty chemonaive International Federation of Gynecology and Obstetrics (FIGO) stage IIIc and stage IV subjects with ovarian cancer.

MAIN OUTCOME MEASURES

Tumour response, disease free and overall survival and toxicity.

METHODS

Intravenous gemcitabine 1000 mg/m2 on day 1 and day 8 and carboplatin at area under centre (AUC) = 5 on day 1 were administered three weekly for six cycles. Subjects who received more than three cycles of chemotherapy were eligible for assessment of tumour response, while all the cycles of chemotherapy were assessed for toxicities.

RESULTS

The mean age of the subjects was 57.3 years, and the median follow up was 38.7 months. Of the 18 eligible subjects analysed, 11 (61.1%) showed a complete clinical response, and the overall response rate was 83.3% (15/18). The median overall survival was 29.2 [95% (confidence interval) CI 22.8-35.6] months, and the median progression-free survival was 11.6 (95% CI 4.7-18.5) months. WHO grade 3 anaemia, neutropenia and thrombocytopenia was 7.6, 9.5 and 0%, respectively, on day 8, and 15.5, 12.2 and 15.5%, respectively, on day 15. Two subjects required a total of three hospital admissions for neutropenic sepsis, and two required five hospital admissions for platelet transfusion for severe thrombocytopenia.

CONCLUSION

Chemonaive advanced ovarian cancer showed a high response rate to combined gemcitabine and carboplatin chemotherapy. The subjects developed moderate adverse reactions. Phase III study to evaluate the role of combined gemcitabine and carboplatin as first-line chemotherapy in ovarian cancer is warranted.

The in-vitro activity of colistin in gram-negative bacteria

INTRODUCTION

Colistin is a polypeptide antibiotic belonging to the polymyxins, and has been increasingly used for the treatment of multiresistant gram-negative infections. There is little current available data on the susceptibility of gram-negative bacilli to colistin, in part because susceptibility testing for colistin remains problematic, and also because the use of colistin is not widespread. This study tested clinical isolates of gram-negative bacilli for susceptibility to colistin using the reference susceptibility testing method of agar dilution.

METHODS

102 strains of gram-negative bacilli were collected over a one-year period. Antibiotic susceptibility profiles were derived from disc susceptibility testing, and organisms were identified by standard microbiological methods. Isolates were selected for inclusion in the study using susceptibility profiles and epidemiological data. Minimum inhibitory concentrations to colistin were obtained by performing agar dilution according to a standardised method.

RESULTS

30 percent of tested isolates were resistant to colistin. All Acinetobacter spp. and Escherichia coli were susceptible to colistin. Colistin resistance was detected predominantly in Stenotrophomonas maltophilia and Pseudomonas aeruginosa, but was also present in Enterobacter spp. and Klebsiella spp.

CONCLUSION

Colistin resistance is uncommon in the Enterobacteriaceae, but present in a significant proportion of S. maltophilia and P. aeruginosa isolates. From the results of this study, we recommend that susceptibility testing be performed whenever the clinical use of the polymyxins is considered.

Enlarged cervical sympathetic ganglion: an unusual parapharyngeal space tumour

Primary parapharyngeal space tumours are rare, but they pose not only diagnostic but also therapeutic challenges in head and neck surgery. Imaging studies, in particular magnetic resonance (MR) imaging, play a central role in the diagnosis of parapharyngeal space (PPS) tumours. Besides schwannomas, primary lesions arising from the sympathetic chain within the PPS are extremely rare. We describe a 49-year-old man in whom the cervical sympathetic ganglion became enlarged after radiotherapy for nasopharyngeal carcinoma, and appeared as a parapharyngeal mass. This phenomenon has not been reported in the literature. We also discuss the features of the enlarged cervical sympathetic ganglion on MR imaging.

Emergence of community-associated methicillin-resistant Staphylococcus aureus in Singapore: a further six cases

INTRODUCTION

The clinical features and molecular epidemiology of further cases of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infection in Singapore are described.

METHODS

Six cases of CA-MRSA infection that occurred between April and October 2004 are described. The bacterial isolates were tested for the presence of Panton-Valentine leukocidin (PVL) genes and typed via pulsedfield gel electrophoresis, staphylococcal chromosomal cassette mec (SCCmec) and multi-locus sequence typing. The results were compared with that of previously-reported local and international CA-MRSA isolates.

RESULTS

There were four cases of cutaneous abscesses and one each of chronic osteomyelitis and endocarditis. CA-MRSA isolates from the last two cases tested negative for PVL genes. Three isolates were identical and related to the Oceanian clone, and one isolate to the predominant Taiwanese clone. The isolate causing osteomyelitis had a novel sequence type.

CONCLUSION

CA-MRSA, though uncommon, is being isolated with increasing frequency in Singapore. A predominant clone (ST30- MRSA-IV) seems to be emerging locally.

Point-of-care controls for nosocomial legionellosis combined with chlorine dioxide potable water decontamination: a two-year survey at a Welsh teaching hospital

This study reports a two-year programme of attempted eradication of Legionella colonization in the potable water supply of a 1000-bed tertiary care teaching hospital in Wales. There was a simultaneous, point-of-care, sterile-water-only policy for all intensive care units (ICU) and bone marrow and renal transplant units in order to prevent acquisition of nosocomial Legionnaires' disease. The programme was initiated following a case of nosocomial pneumonia caused by Legionella pneumophila serogroup 1-Bellingham-like genotype A on the cardiac ICU. The case occurred 14 days after mitral and aortic valve replacement surgery. Clinical and epidemiological investigations implicated aspiration of hospital potable water as the mechanism of infection. Despite interventions with chlorine dioxide costing over 25000 UK pounds per annum, Legionella has remained persistently present in significant numbers (up to 20000 colony forming units/L) and with little reduction in the number of positive sites. Two further cases of nosocomial disease occurred over the following two-year period; in one case, aspiration of tap water was implicated again, and in the other case, instillation of contaminated water into the right main bronchus via a misplaced nasogastric tube was implicated. These cases arose because of inadvertent non-compliance with the sterile-water-only policy in high-risk locations. Enhanced clinical surveillance over the same two-year period detected no other cases of nosocomial disease. This study suggests that attempts at eradication of Legionella spp. from complex water systems may not be a cost-effective measure for prevention of nosocomial infections, and to the best of our knowledge is the first study from the UK to suggest that the introduction of a sterile-water-only policy for ICUs and other high-risk units may be a more cost-effective approach.

Facial palsy from temporal bone lesions

INTRODUCTION

Facial nerve palsy results in the loss of facial expression and is most commonly caused by a benign self-limiting inflammatory condition, known as Bell's palsy. However, there are other conditions which may result in injury of the seventh cranial nerve and the radiologist should be familiar with their imaging appearances.

MATERIALS AND METHODS

The relevant anatomy of the facial nerve and pathology which may affect the intratemporal portion of the nerve is described. The role of imaging and choice of imaging modality is also reviewed.

RESULTS

High-resolution computer tomography(HRCT) images of the temporal bone and magnetic resonance(MR) images of the facial nerve from 11 patients who presented with facial nerve palsy were used to illustrate how intratemporal facial nerve injury of other aetiologies can mimic Bell's palsy. The typical imaging appearance of Bell's palsy was also presented.

CONCLUSIONS

Most patients with suspected Bell's palsy do not require radiologic imaging. However, when symptoms progress, persist or when there is multiple cranial nerve involvement, recurrent symptoms or subacute onset of facial nerve palsy, causes other than Bell's palsy should be considered.

Spontaneous cerebrospinal fluid otorrhoea via oval window: an obscure cause of recurrent meningitis

Spontaneous cerebrospinal fluid (CSF) leak via the oval window is uncommon and can result in recurrent bacterial meningitis. Current understanding of spontaneous CSF otorrhoea is reviewed and a diagnostic algorithm is presented. A seven-year-old boy presented with bilateral congenital deafness and recurrent meningitis. High-resolution computed tomography (HRCT) of the temporal bone showed a labyrinthine deformity and communication between the internal auditory canal (IAC) and the cochlea. Subtotal petrosectomy with closure of the external acoustic meatus and eustachian tube was performed. Post-operatively, the child had no further episodes of meningitis. This rare and obscure cause of recurrent childhood meningitis requires a high index of suspicion and the use of diagnostic tools, especially HRCT.

Castleman's disease of the neck: a description of four cases on contrast-enhanced CT

Castleman's disease of the neck is an uncommon benign lymphoproliferative disease that usually presents as homogeneously enhancing enlarged lymph nodes on contrast-enhanced CT scan. We described the appearance of four confirmed cases of Castleman's disease of the neck on contrast-enhanced CT scan. Three of these presented as a solitary enhancing lymph node and the fourth case presented with multiple bilateral enhancing lymph nodes. A central non-enhancing area was present in two of the three cases that presented as a solitary node. Pathological correlation of one of these cases showed that this was due to a central fibrotic scar. One of the enhancing nodes in the fourth case with multiple and bilateral lymphadenopathy also contained a central non-enhancing area. We would like to propose that if a central non-enhancing scar is observed in an enhancing lymph node in the neck on CT scan, Castleman's disease should be considered as a possible diagnosis.

Temporal lobe encephalocoele presenting with seizures and hearing loss

A case of a bilateral temporal lobe encephalocoele that presented as seizures and hearing loss for many years. Diagnosis was confirmed on CT and MR imaging, which showed deficiencies in the temporal bone. The patient subsequently underwent surgical repair and recovered from his presenting symptoms.

Idiopathic chronic fetomaternal haemorrhage resulting in hydrops--a case report

INTRODUCTION

We report a case of idiopathic chronic fetomaternal haemorrhage (FMH) that developed in the late trimester.

CLINICAL PRESENTATION

The patient presented with decreased fetal movement at 38 weeks gestation. Antenatal follow-up was uneventful with normal serial ultrasound performed at 22 and 35 weeks. Prior to delivery, the cardiotocography (CTG) was abnormal with decreased baseline variability and late deceleration. Emergency lower segment caesarean section was performed. Upon delivery, a hydropic neonate with a haemoglobin level of 3.9 g/dL was noted. The Kleihauer-Betke test was positive, confirming FMH.

OUTCOME

The neonate later developed intraventricular haemorrhage (IVH) and spastic cerebral palsy on follow-up.

DISCUSSION

It is possible for FMH to occur late at the third trimester leading to detrimental effect. The fact that FMH can occur without antecedent risk factors underscores the importance of further research, and a high index of suspicion.

Severe newborn encephalopathy unrelated to intrapartum hypoxic events: 3 case reports

INTRODUCTION

Newborn encephalopathy is an important clinical problem associated with considerable morbidity and mortality and is pertinent in the assignment of blame in obstetrics litigation.

CLINICAL PICTURE

We report 3 babies with severe neonatal encephalopathy.

OUTCOME

In all 3 cases, intrapartum hypoxic insult was unlikely to be a significant contributing factor towards the development of neonatal encephalopathy. The aetiology was unclear in the first 2 cases and there was antecedent antenatal cause of feto-maternal haemorrhage in the last case.

CONCLUSION

Prevention of neonatal encephalopathy was not possible in these 3 cases. We recommend that umbilical cord blood gases be clearly documented in such cases to reduce unnecessary obstetrics litigation of intrapartum asphyxia as the significant contributing factor to the poor neonatal outcome. Clinicians must have a high index of suspicion of antecedent causes and perform the necessary investigations to elucidate the aetiology of the neonatal encephalopathy.

A case series of pre-viable severe twin-twin transfusion syndrome

INTRODUCTION

We present a case series of pre-viable severe twin-twin transfusion syndrome (TTTS).

CLINICAL PICTURE

In year 2000, there were 16,688 deliveries in KK Women's and Children's Hospital. Four cases that presented before 24 weeks gestation satisfied the sonographic criteria for severe TTTS: same-sex fetuses, absence of twin peak sign, thin intertwine membrane, polyhydramnios associated with large bladder in recipient twin, and oligohydramnios and small or absent bladder in donor twin.

TREATMENT

Amnioreduction, septostomy and termination of pregnancy were offered.

OUTCOME

In 1 case abortion was chosen. The follow-up was at least 18 months postnatal. There was 1 intrauterine death, 2 with severe neurological handicap and 3 with normal outcome.

CONCLUSION

Pre-viable severe TTTS is associated with significant mortality and morbidity rates and should be diagnosed promptly and managed in a tertiary fetal medicine unit with multi-disciplinary input.

Imaging of congenital middle ear deafness

INTRODUCTION

Conductive hearing loss, in the presence of a normal external ear, is usually due to an interference with the normal transmission of sound from the tympanic membrane across the ossicular chain to the oval window. If conductive hearing loss occurs in a young child, congenital middle ear pathology is the most likely cause.

MATERIALS AND METHODS

High resolution computed tomography of the middle ear is the diagnostic modality of choice. Details of the imaging technique are outlined in this article. Eight cases of congenital middle ear deafness imaged in the radiological departments of Changi General Hospital and Tan Tock Seng Hospital in Singapore are illustrated.

RESULTS

Congenital middle ear deafness may be classified into ossicular chain abnormalities, congenital ossicular fixation, congenital oval window atresia and congenital round window atresia. The imaging features for each category are described.

CONCLUSION

With proper imaging technique and a systemic analysis of the images, the abnormalities that result in congenital middle ear deafness can usually be demonstrated on most occasions.

Advances in imaging in prenatal diagnosis and fetal therapy

Technological advances in ultrasound have contributed to improvements in prenatal diagnosis. Transvaginal scanning and harmonic imaging have allowed better resolution and improved structural characterisation. Doppler techniques have further been improved, which allow accurate flow studies of vessels in the placenta and fetus. These have contributed much to the management of intrauterine growth restriction, fetal anaemia and twin-twin transfusion syndrome (TTTS). Three-dimensional sonography and magnetic resonance imaging ultrafast sequences are useful adjuncts to conventional 2-dimensional sonography, increasing the confidence and diagnostic accuracy of prenatal diagnosis. Fetal therapy has seen major advances in recent years as well, secondary to improvements in endoscopic instruments and surgical techniques. Selective Nd:YAG laser photocoagulation of communicating vessels and cord occlusion have been used to treat complications of monochorionic twins like TTTS and twin-reversed arterial perfusion sequence.