Not Dandy Walker variant: a review of prominent retrocerebellar CSF space in children.

The prominent retrocerebellar cerebrospinal fluid (CSF) space can be frequently encountered on paediatric neuroimaging studies. In cases involving abnormal vermian development where imaging does not align with the established criteria of Dandy-Walker malformation (DWM), the term "Dandy-Walker variant or continuum" has been historically employed to describe the aberrant posterior fossa development. Instead, the emphasis is on a more elaborate description of the findings in the posterior fossa. Moreover, combining the findings in the supratentorial brain can occasionally predict certain neurogenetic disorders that mimic Dandy-Walker phenotype. The present review demonstrates and differentiates the imaging features of various entities that result in an enlarged retrocerebellar CSF space, such as inferior vermian hypoplasia (IVH) and several neurogenetic conditions.

The paediatric thymus: recognising normal and ectopic thymic tissue.

The appearance of the paediatric thymus changes as the normal process of thymic involution occurs. Thymic tissue may be orthotopic within the anterior mediastinum or ectopically located along the course of its embryological development. The variable appearance of orthotopic and ectopic thymic tissue in children on imaging studies may lead to misinterpretation of the normal thymus as pathology. Recognition of normal thymic tissue can mitigate unnecessary further diagnostic testing and patient anxiety. In this review, we discuss the embryological development and anatomical variants of normal thymus, and demonstrate the multimodality imaging features of the normal thymus in children, including positron-emission tomography, and diffusion-weighted imaging and in- and opposed-phase imaging on magnetic resonance imaging. We demonstrate the normal thymus mimicking pathological processes and discuss features that distinguish normal thymus, including thymic rebound hyperplasia, from pathology.

Adult human metapneumovirus encephalitis: A case report highlighting challenges in clinical management and functional outcome.

We report a rare case of adult human metapneumovirus (HMPV) in a healthy 32-year-old man. There was dramatic deterioration in his condition developing pneumonia with Type-I respiratory failure and encephalitis. He needed mechanical ventilation in the intensive care setting and was treated with intravenous ribavirin. Post-extubation he remained severely physically and cognitively impaired despite rehabilitation. Treatment of HMPV pneumonia is at present, still without specific antiviral therapy. Managing HMPV-encephalitis remained supportive and challenging. More definite treatment strategies are needed.

Biochemical and molecular characteristics of Malaysian patients with lysinuric protein intolerance.

Lysinuric protein intolerance (LPI) is an inborn error of dibasic amino acid transport due to a defect in the dibasic amino acid transporter in the renal and intestine and has a heterogenous presentation. Three Malaysian patients with LPI were studied and their biochemical and molecular findings compared. There were differences and similarities in the biochemical and molecular findings. Molecular analysis of SLC7A7 gene revealed a novel mutation c.235G>A; p.(Gly79Arg) in exon three in Patient 1 and a mutation c.1417C>T; p.(Arg473*) in exon 10 in patient 2 and 3. The degree of concentration of dibasic amino acids may determine the type of disease of the cell membrane transport, however, a positive molecular confirmation will secure the diagnosis.

Treatment of Lesch-Nyhan disease with S-adenosylmethionine: experience with five young Malaysians, including a girl.

BACKGROUND: Lesch-Nyhan disease (LND) is a rare X-linked recessive neurogenetic disorder caused by deficiency of the purine salvage enzyme hypoxanthine phosphoribosyltransferase (HPRT, EC 2.4.2.8) which is responsible for recycling purine bases into purine nucleotides. Affected individuals have hyperuricemia leading to gout and urolithiasis, accompanied by a characteristic severe neurobehavioural phenotype with compulsive self-mutilation, extrapyramidal motor disturbances and cognitive impairment. AIM: For its theoretical therapeutic potential to replenish the brain purine nucleotide pool, oral supplementation with S-adenosylmethionine (SAMe) was trialed in 5 Malaysian children with LND, comprising 4 related Malay children from 2 families, including an LND girl, and a Chinese Malaysian boy. RESULTS: Dramatic reductions of self-injury and aggressive behaviour, as well as a milder reduction of dystonia, were observed in all 5 patients. Other LND neurological symptoms did not improve during SAMe therapy. DISCUSSION: Molecular mechanisms proposed for LND neuropathology include GTP depletion in the brain leading to impaired dopamine synthesis, dysfunction of G-protein-mediated signal transduction, and defective developmental programming of dopamine neurons. The improvement of our LND patients on SAMe, particularly the hallmark self-injurious behaviour, echoed clinical progress reported with another purine nucleotide depletion disorder, Arts Syndrome, but contrasted lack of benefit with the purine disorder adenylosuccinate lyase deficiency. This first report of a trial of SAMe therapy in LND children showed remarkably encouraging results that warrant larger studies.

Diagnosis of virus infection in orchid plants with high-resolution optical coherence tomography.

This work investigates the use of optical coherence tomography (OCT) to identify virus infection in orchid plants. Besides revealing the cross-sectional structure of orchid leaves, highly scattering upper leaf epidermides are detected with OCT for virus-infected plants. This distinct feature is not observable under histological examination of the leaf samples. Furthermore, the leaf epidermides of stressed but healthy plants, which exhibit similar visual symptoms as virus-infected plants, are not highly scattering and are similar to those of healthy plants. The results suggest that virus-infected orchid plants can be accurately identified by imaging the epidermal layers of their leaves with OCT. The OCT modality is suitable for fast, nondestructive diagnosis of orchid virus infection, which may potentially lead to significant cost savings and better control of the spread of viruses in the orchid industry.

Racial differences in responses to interferon-beta-1a in chronic hepatitis C unresponsive to interferon-alpha: a better response in Chinese patients.

Re-treatment with interferon-alpha alone for chronic hepatitis C nonresponders to interferon-alpha monotherapy is almost ineffective. This multicentre, randomized, parallel-group, dose-finding study evaluated the efficacy of interferon-beta-1a in the treatment of chronic hepatitis C patients unresponsive to interferon-alpha. A total of 267 patients were randomized to one of four groups: subcutaneous interferon-beta-1a 12 MIU (44 microg) or 24 MIU (88 microg) administered three times weekly or daily. Patients were treated for 48 weeks and then followed up for an additional 24 weeks. There was a trend towards a dose-response relationship regarding virological [loss of detectable serum hepatitis C virus (HCV) RNA] and biochemical response (normalization of serum alanine aminotransferase). Overall, 22 patients (8.3%) had a virological response at the end of treatment; nine patients (3.4%) had a sustained virological response (SVR). Strikingly, 21.7% (5/23) of Chinese patients achieved SVR. Univariate analysis revealed that race was the only variable related to SVR [odds ratio (OR) 16.6; 95% CI 4.1-67.3; P < 0.0001]. Multiple logistic regression analysis also confirmed that more Chinese patients achieved SVR than non-Chinese patients (OR 12.3; 95% CI 2.6-59.3; P = 0.0017). In addition, complete clearance of HCV-RNA occurred earlier in Chinese than in non-Chinese responders (median 2 vs 30 weeks; P = 0.020). Thirty-six patients were withdrawn from treatment because of adverse events. Most adverse events were mild or moderate in severity. In conclusion, interferon-beta-1a provided considerable clinical benefit in Chinese patients with chronic hepatitis C unresponsive to interferon-alpha. The evaluation of interferon-beta-1a in this setting is progressing.

Survival among Chinese women with lung cancer in Singapore: a comparison by stage, histology and smoking status.

Lung cancer generally carries a poor prognosis and the determinants of survival have been of interest. However, survival estimates in Asian populations are scarce. This study describes survival rates and their determinants in Singapore Chinese women, a primarily non-smoking population. Three hundred and twenty-six Chinese women, diagnosed with primary lung carcinoma in three major hospitals in Singapore between April 1996 and December 1998, were followed up till 31 December 2000. The Kaplan-Meier method was used for survival analysis. Two hundred and eighty (85.7%) died from the disease during follow-up. The median survival time was 0.7 years and the three-year survival was 15.8%. These survival rates are similar to those of Western populations, and they provide a basis for examining trends over time. Age at diagnosis was an independent prognostic factor [adjusted hazard ratio (relative risk) 1.4, 95% confidence intervals (CI) 1.1-1.9 for women above 65 years relative to younger women]. Most (70.5%) tumours were stage III/IV at diagnosis. Three-year survival ranged from 72% among patients with stage I tumours to 7% for stage IV tumours. Overall, there was no survival difference among different histological types in all stages combined. When limited to stages I and II cancers, adenocarcinomas were associated with a better outcome relative to other histological subtypes combined (adjusted relative risk 0.4, 95% CI 0.1-1.0). Smoking was an independent risk factor (adjusted relative risk 1.3, 95% CI 1.0-1.8). Nevertheless, non-smokers comprised 57.4% of this series, highlighting the importance of increased awareness among health professionals and the public that lung cancer is not only a disease of smokers. The high proportion of late-stage tumours in this study and the impact of disease stage on outcome underline the importance of early detection in improving survival of lung cancer.

Light and scanning electron microscopic evaluation of Glyde File Prep in smear layer removal.

AIM: To evaluate the effectiveness of Glyde File Prep used in conjunction with sodium hypochlorite irrigation in the removal of smear layer produced during root canal instrumentation. METHODOLOGY: Thirty-nine extracted human teeth with single root canals were used. Access cavities were prepared and the teeth divided into three groups of 13 teeth each. Each group was treated by one of the three different regimes of irrigation and conditioning during root canal instrumentation. Group A: 0.5 mL of 1% NaOCl irrigation after each file size with an additional final irrigation of 10 mL 1% NaOCl; group B: 0.5 mL of 1% NaOCl irrigation after each file size with an additional final irrigation of 10 mL 17% EDTA; group C: Glyde File Prep coated on each instrumentation file used in conjunction with 0.5 mL 1% NaOCl irrigation after each file size and an additional final irrigation of 10 mL 1% NaOCl. The teeth were then longitudinally grooved and sectioned. Root canal cleanliness was evaluated with the aid of a Nikon light microscope (x40 and x100) and scanning electron microscope (x1000 and x3000). The debris scores obtained at three canal regions were compared statistically within the same group and among different groups using repeated measurements of analysis of variance (anova) with Bonferroni adjustments and anova with posthoc Tukey HSD, respectively. RESULTS: The canals treated with EDTA and Glyde File Prep were significantly cleaner than those treated with NaOCl alone. The apical region of the root canals generally displayed more residual smear layer, but the difference was not significant. CONCLUSIONS: Used in conjunction with NaOCl irrigation, Glyde File Prep was effective in removing smear layer produced during root canal instrumentation.

Effective monosomy or trisomy of chromosome band 2q37.3 due to the unbalanced segregation of a 2;11 translocation.

We report a seven generation family in which a 2;11 chromosome translocation is segregating. Both unbalanced segregants have been found in the family, and cytogenetic analysis demonstrates that this results in effective monosomy or trisomy for chromosome band 2q37.3. Those family members who are monosomic exhibit a variable phenotype with a number of features associated with an Albright's Hereditary Osteodystrophy-like phenotype (AHO-like) whilst those who are trisomic have a phenotypic spectrum ranging from mild facial anomalies and growth retardation to apparent normality. The latter group of patients represent the first reported patients with pure trisomy for chromosome band 2q37.3.

Excimer laser photorefractive keratectomy for the correction of myopia.

AIM OF STUDY: To ascertain the efficacy, predictability, safety and stability of photorefractive keratectomy (PRK) for the correction of myopia. METHODS: Nine-hundred and seventy-one eyes of 628 patients had PRK performed for the correction of myopia. The mean pre-operative myopia was -5.7 D +/- 2.21 D (range -1.0 D to -15.25 D). The mean attempted correction was -5.0 D +/- 1.9 D (range -1.0 D to -9.90 D). RESULTS: Four-hundred and sixty-seven eyes had a follow-up of 6 months or more. Ninety-three percent of low myopic eyes (pre-operative myopia of less than or equal to 6.0 D) and 75% of high myopic eyes (pre-operative myopia of more than 6.0 D) attained an unaided visual acuity of 6/12 or better. Seventy-four percent of low myopic and 50% of high myopic eyes were within 1 D of the intended correction. The mean post-operative refraction at 6 months was 0.60 D +/- 1.46 D. Eight eyes in the high myopia group and 1 eye in the low myope group lost 2 or more lines or best-corrected visual acuity. CONCLUSION: PRK was safer and produced better results for low myopes.

Electroretinographic profile in emmetropic Singaporean eyes.

OBJECTIVES: To characterise the electroretinographic (ERG) profile in 70 Singaporean emmetropic eyes. METHOD: Seventy eyes of thirty-five patients with refractive error of -1.00D or less and with a normal ophthalmic examination were chosen. They were subjected to three flash patterns generated with a Nihon-Kohden Flash Stimulator. The results were captured on a Nihon-Kohden Neuropack 8. RESULTS: The mean age of the patients was 25 years (range 20 to 30). The mean spherical refractive error was -0.3D (range 0D to -1.00D). For the scotopic dim flash, the mean amplitude for the 'b' wave was 304.6 +/- 69.2 mu v (range 175 mu v to 469 mu v) and the mean latency was 47.56 +/- 4.87 ms (range 41.2 ms to 62.0 ms). For the scotopic bright flash, the mean amplitude for the 'b' wave was 469.54 +/- 127.15 mu v (range 257 mu v to 750 mu v) and the mean latency was 40.54 +/- 3.91 ms (range 32.0 ms to 48.9 ms). In the flicker response, the mean amplitude for the 'b' wave was 34.19 +/- 12.97 mu v (range 14 mu v to 64 mu v) with mean latency at 34.46 +/- 0.58 ms (range 33.1 ms to 35.9 ms). CONCLUSION: With ERG normal values so generated, comparisons with these can then be made for abnormal cases.

Age-related changes in pharyngeal and supraglottic sensation.

As one ages, sensory discrimination in the oral cavity progressively diminishes, and dysphagia and aspiration are more likely to occur. Whether similar age-related laryngeal and pharyngeal sensory abnormalities exist and contribute to dysphagia and aspiration is unknown. The purpose of this study was to determine if sensory discrimination in the area innervated by the superior laryngeal nerve diminishes with increasing age. By applying a previously described new device and technique that utilizes brief air pulse stimulation of the anterior wall of the pyriform sinus, sensory discrimination can be reliably determined. We carried out 672 trials in 56 healthy adults divided into three age groups: 20 to 40, 41 to 60, and 61 to 90 years of age. Overall, the average sensory discrimination was 2.30 +/- 0.50 mm Hg. In subjects 20 to 40 years of age, sensory discrimination was 2.07 +/- 0.20 mm Hg, while in subjects 61 to 90 years of age, sensory discrimination was 2.68 +/- 0.63 mm Hg (p < .05). There also was a statistically significant difference between the 41- to 60-year and 61- to 90-year age groups (p < .05). Progressive diminution in pharyngeal and supraglottic sensitivity with increasing age might be a contributing factor in the development of dysphagia and aspiration in the elderly.

Achondroplasia-hypochondroplasia complex.

We report on a 14-year-old girl with the achondroplasia-hypochondroplasia complex. This patient has been reported previously [McKusick et al, 1973], and we offer an update on her condition. The patient has clinical features different from both achondroplasia and hypochondroplasia and is mentally retarded. Radiological changes, which have occurred over 14 years, are included.

Further delineation of Weaver syndrome.

Seven new cases of Weaver syndrome are described, including the first reported case in an adult. Overgrowth is usually but not always present. The combination of characteristic facies and developmental delay, with the peculiar radiographic findings of accelerated dysharmonic osseous maturation and splaying of the distal long bones, is diagnostic of Weaver syndrome.

Previously undescribed syndrome of craniofacial, hand anomalies, and sensorineural deafness.

We describe in a mother and her infant daughter a previously unreported syndrome of unusual craniofacial, hand, and digital anomalies. Both mother and child have a flat facial profile, hypertelorism, hypoplastic nose with slit-like nares, and a sensorineural hearing loss. Common radiographic manifestations include small maxilla, absent or small nasal bones, and ulnar deviation of the hands. This is either an autosomal dominant or X-linked trait.