Sub-50 fs Yb-doped laser with anomalous-dispersion photonic crystal fiber

We report on the generation of 42 fs pulses at 1 μm in a completely fiber-integrated format, which are, to the best of our knowledge, the shortest from all-fiber-integrated Yb-doped fiber lasers to date. The ring fiber cavity incorporates anomalous-dispersion, solid-core photonic crystal fiber with low birefringence, which acts as a broadband, in-fiber Lyot filter to facilitate mode locking. The oscillator operates in the stretched-pulse regime under slight normal net cavity dispersion. The cavity generates 4.7 ps long pulses with a spectral bandwidth of 58.2 nm, which are dechirped to 42 fs via a grating pair compressor outside of the cavity. Relative intensity noise (RIN) of the laser is characterized, with the integrated RIN found to be 0.026% in the 3 Hz-250 kHz frequency range.

Congenital Descending Colonic Stenosis with Perforation of Transverse Colon in a Neonate: A Case Report

Colonic atresia and stenosis are rare causes of intestinal obstruction in the infant. Only 10 cases have been reported in Literature since 1966 and only one late-onset case has been reported in Literature until now. We describe the case of a 3 day old baby presenting with abdominal distension, failure to pass meconium and vomiting. X-ray of the abdomen showed dilated gut loops. Exploratory laparotomy was performed. At the junction of descending and sigmoid colon a stenosis was found, laparotomy also revealed a perforation of transverse colon. Transverse colostomy and a mucous fistula of sigmoid colon was performed after resecting stenosing segment and colon distal to perforation site upto stenosing site. Diagnosis was confirmed on histopathology. Colostomy was close after six weaks with uneventful recovery. Considering both the Literature and our case, congenital colonic stenosis should be considered one of the rare differential diagnoses in a neonate presenting as complete or partial intestinal obstruction. Key words: Colonic Stenosis; Perforation; Obstruction DOI: http://dx.doi.org/10.3126/jnps.v32i1.5446   J. Nepal Paediatr. Soc. Vol.32(1) 2012 73-75  

Transcripts from a novel BMPR2 termination mutation escape nonsense mediated decay by downstream translation re-initiation: implications for treating pulmonary hypertension

Bone morphogenetic protein receptor type 2 (BMPR2) gene mutations are a major risk factor for heritable pulmonary arterial hypertension (HPAH), an autosomal dominant fatal disease. We have previously shown that BMPR2 transcripts that contain premature termination codon (PTC) mutations are rapidly and nearly completely degraded through nonsense mediated decay (NMD). Here we report a unique PTC mutation (W13X) that did not behave in the predicted manner. We found that patient-derived cultured lymphocytes (CLs) contained readily detectable levels of the PTC-containing transcript. Further analysis suggested that this transcript escaped NMD by translational re-initiation at a downstream Kozak sequence, resulting in the omission of 173 amino acids. Treatment of CLs containing the PTC with an aminoglycoside decreased the truncated protein levels, with a reciprocal increase in full-length BMPR2 protein and, importantly, BMPR-II signaling. This is the first demonstration of aminoglycoside-mediated 'repair' of a BMPR2 mutation at the protein level in patient-derived cells and has obvious implications for treatment of HPAH where no disease-specific treatment options are available. Our data also suggest the need for a more thorough characterization of mutations prior to labeling them as haploinsufficient or dominant negative based simply on sequencing data.

Alterations in oestrogen metabolism: implications for higher penetrance of familial pulmonary arterial hypertension in females

Mutations in bone morphogenetic protein receptor type 2 (BMPR2) cause familial pulmonary arterial hypertension (FPAH), but the penetrance is reduced and females are significantly overrepresented. In addition, gene expression data implicating the oestrogen-metabolising enzyme CYP1B1 suggests a detrimental role of oestrogens or oestrogen metabolites. We examined genetic and metabolic markers of altered oestrogen metabolism in subjects with a BMPR2 mutation. Genotypes for CYP1B1 Asn453Ser (N453S) were determined for 140 BMPR2 mutation carriers (86 females and 54 males). Nested from those subjects, a case-control study of urinary oestrogen metabolite levels (2-hydroxyoestrogen (2-OHE) and 16alpha-hydroxyoestrone (16alpha-OHE(1))) was conducted in females (five affected mutation carriers versus six unaffected mutation carriers). Among females, there was four-fold higher penetrance among subjects homozygous for the wild-type genotype (N/N) than those with N/S or S/S genotypes (p = 0.005). Consistent with this finding, the 2-OHE/16alpha-OHE(1) ratio was 2.3-fold lower in affected mutation carriers compared to unaffected mutation carriers (p = 0.006). Our findings suggest that variations in oestrogens and oestrogen metabolism modify FPAH risk. Further investigation of the role of oestrogens in this disease with profound sex bias may yield new insights and, perhaps, therapeutic interventions.

Clinical picture of craniopharyngioma in childhood

This cross sectional and observational study was carried out among the admitted patients of the department of Neurosurgery, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka during the period of 1st March 2004 to 31st March 2005. Among the all intracranial tumours, 2.5-04% are Craniopharyngiomas. Although there is a bi-modal age distribution-1st peak at 5-10 years and the 2nd peak at 55-65 years, the common patients are children (9% of childhood tumour). A typical child with Craniopharyngioma (CP) is short, obese and half blind and has a poor school record. The study has been undertaken to know in details, how child patients with Craniopharyngiomas in Bangladesh present their disease at the hospital. Earlier diagnosis and management may improve the quality of life and longivity. The average age of the patients was 13 years ranging from 07 to 17 years. The vast majority patients were admitted with visual problems as their presenting complaints. Among the patients 33% had total blindness of which 03 had primary optic atrophy and 1 has secondary optic atrophy. Among the remaining 08 patients, 75% were found to have field defect. All patients showed fundal changes ranging from early papilloedema to optic atrophy. We found major endocrinological deficiency in child patients with Craniopharyngioma in 17% cases. Raised Prolactin level may not be significant, because it could be due to stalk effect. Although 25% patients were of short stature, their hormonal profile was within normal range according to age and sex.

Long-term urological outcomes in paediatric spinal cord injury

STUDY DESIGN

Retrospective review.

OBJECTIVE

This retrospective review observes the evolution of bladder management by time and reports adult urological outcomes and complications in paediatric onset spinal cord injury (SCI).

SETTING

Spinal Injuries Unit RNOH Stanmore.

METHOD

In total, 10 traumatic SCI patients with mean age at injury of 13.6 years underwent treatment, for a mean period of 13.1 years. Characteristics of injury were noted. Two diagnostic subgroups, neurogenic detrusor overactivity (NDO), and acontractile detrusor were made. Complications, treatment changes, operative procedures with follow-up were noted.

RESULTS

In group 1 (6/10 patients) with NDO, five had DSD. Initial bladder management was reflex/urge voiding (n=4), suprapubic catheterisation (SPC), (n=1) and self-intermittent catheterisation (SIC), (n=1). Two patients had multiple upper tract complications with decreased renal function, two recurrent symptomatic urinary infections and one; bladder calculus. In total, 12 operative procedures were performed to treat complications and change bladder management to, SIC+oxybutynin (n=3), ileal conduit (n=1), sacral anterior root stimulator implant (SARSI), (n=1), voiding on urge (n=1). In group 2 (4/10 patients) with a-contractile detrusor two had low compliance. Initial bladder management was SIC (n=3) and voiding on urge/straining (n=1). Two patients converted from SIC to permanent catheter drainage and reported complications. Incidental kidney stone was diagnosed in one. A total of four interventions were carried out with final management of SIC (n=2), voiding on urge/straining (n=1) and Mitrofanoff+ileocystoplasty (n=1).

CONCLUSION

Bladder management in paediatric SCI is dependent on neurological level and type of injury; it changes with growth and is affected by changes in bladder management.

Effects of repeated ejaculations on semen characteristics following spinal cord injury

STUDY DESIGN

Prospective randomised controlled study.

OBJECTIVE

To evaluate the effects of repeated ejaculation on semen characteristics following spinal cord injury (SCI) in a prospective randomised controlled study.

SETTING

Spinal Research Centre, Stanmore, UK and Institute of Urology and Nephrology, London, UK.

METHODS

A total of 74 patients with SCI above T10 were tested by vibro-ejaculation using a Ferticare penile vibrator (Multicept A/S Horsholm, Denmark) using a standardised technique. The ejaculate was examined according to WHO protocol. The successfully vibro-ejaculated subjects (n = 32) were randomised into a study group (n = 18) and a control group (n = 14). The patients in the study group vibro-ejaculated weekly for 3 months with semen analysis performed at baseline and then monthly. The control group vibro-ejaculated at baseline and at the end of the 3-month period. Two experienced observers performed the semen analysis independently. All measures were compared for statistical significance across the two groups at the beginning and at the end of the 3-month period using a two-tailed student t-test. Significance was determined at the 95% confidence interval (P < 0.05).

RESULTS

In total, 10 patients in the study group and nine in the control group have completed the study so far. Six patients have dropped out of the study group and three from the control group for varied reasons. Two patients are currently enrolled in the study and control groups. The morphology and forward progression of sperm shows a statistically significant increase in the study group. The motility improves but is not statistically significant in the study group. No significant adverse effects were reported.

CONCLUSIONS

We have shown in this unique randomised controlled study that repeated ejaculation does improve the sperm characteristics in SCI patients. It is suggested that SCI men should undergo repeated ejaculation for at least 3 months before trying intravaginal or intrauterine insemination techniques. If this fails then in vitro fertilisation can be used. This method promotes natural conception, is intimate and cost effective.

Long-term efficacy of AMS 800 artificial urinary sphincter in male patients with urodynamic stress incontinence due to spinal cord lesion

STUDY DESIGN

Retrospective analysis.

OBJECTIVES

To evaluate long-term efficacy and complications of AMS 800 (American Medical Systems) artificial urinary sphincter (AUS) in treatment of urodynamic stress incontinence (USI) in male patients with spinal cord lesion (SCL).

SETTING

London Spinal Injuries Unit, Stanmore, UK and Institute of Urology and Nephrology, London, UK.

PATIENTS AND METHODS

A retrospective analysis identified nine males with SCL (five thoracic, three lumbar, one cervical) with USI, who underwent AMS 800 AUS implantation by a single surgeon at a specialist spinal injuries unit. The mean age was 38.2 years (range 27-47 years), with the mean time since injury of 13.8 years (range 6-26 years). In all, seven were complete and two were incomplete SCL (traumatic spinal injury eight, tranverse myelitis one). All implants were inserted with the urethral cuff around the bulbar urethra with a 61-70 cm water pressure reservoir in the retropubic space. Implant activation was carried out at 6 weeks postoperatively. All patients were regularly followed up in outpatient clinics at the interval of 3 months, 6 months and yearly thereafter. An ultrasound examination for the upper tracts and a video-cystometrogram (VCMG) was carried out at 3 months postsurgery and then yearly.

RESULTS

The follow-up ranged from 3 to 133 months (mean 70.2 months). All implants were activated successfully with no intra- or immediate-postoperative complications. At activation all patients reported total urinary continence with seven out of nine implants (77%) currently working well. Two patients reported significant recurrent incontinence at 3 month follow-up, one of whom underwent a removal of the entire implant at the end of 3 months and the other was continent after a pump and cuff revision. The implant removed at 3 months was due to erosion and infection while the second was removed at 24 months due to secondary implant infection. Three out of seven (43%) successful implants required one revision each. One patient continues to report minimal leakage only during transfers with no leak demonstrated on postoperative VCMG. One patient with indwelling urethral catheter, two with suprapubic catheter and one voiding on urge have changed their bladder management to intermittent catheterisations postoperatively. All removals and revision procedures were carried out in the first 53 months of follow-up and four out of seven implants (57%) required no revisions.

CONCLUSION

On a long term, AMS 800 is a viable option to treat USI in men with SCL. Mechanical revisions are frequent but effective. Strict patient selection, optimum preoperative bladder management and regular follow-up ensure low complication and high efficacy rates in the long term.

Stress urinary incontinence: current understanding

Many new concepts were introduced in epidemiology, a etiopathology and treatment of stress urinary incontinence. This review gives a short account of these concepts and compares the results of commonly used treatment options with new ones recently introduced.

Stress urinary incontinence: current understanding

Many new concepts were introduced in epidemiology, a etiopathology and treatment of stress urinary incontinence. This review gives a short account of these concepts and compares the results of commonly used treatment options with new ones recently introduced.

Comparison of alamar blue and MTT assays for high through-put screening

The performance of alamar blue and 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) cell viability assays in a high through-put format were compared. A total of 117 drugs chosen for their wide range of therapeutic areas were screened at 10 microM using both assays in human hepatoma cell line HepG2. Except for terfenadine and astemizole, which performed consistently in both assays, the alamar blue assay was slightly more sensitive than the MTT assay for most compounds. The MTT assay was less sensitive detecting an effect for daunorubicin and trifluoperazine. Seven drugs, astemizole, daunorubicin, ellipticine, fluphenazine, terfenadine, thioridazine and trifluoperazine, had percent viability results of 55% or less in the alamar blue assay at the single point screen. These were re-tested in both assays for reconfirmation of cytotoxicity and determination of the EC50 values. Except for daunorubicin, the EC50 values were comparable in both assays. Based on these results and the Z'-factor assessment of assay quality, both assays provided useful information to identify in vitro cytotoxic drugs at early stages of drug candidate selection. However, careful interpretation of data is warranted due to the possibility of false positive or negative results caused by inducers and/or inhibitors of metabolic enzymes that are responsible for transformation of cell toxicity end points, as we demonstrated using dicumarol.

Intratesticular cysts and malignant potential: conservative management is an option

Benign intratesticular cysts are rare, but recognition is essential to prevent unnecessary surgical intervention. The diagnostic dilemma is to differentiate these cysts from testicular malignancy. As they are extremely uncommon, experience of their management is limited and controversial. We present a case of a simple intratesticular cyst and discuss the diagnostic and management principles.