X-ray structure of 5-aminolaevulinate dehydratase, a hybrid aldolase

5-Aminolaevulinate dehydratase (ALAD) is a homo-octameric metallo-enzyme that catalyses the formation of porphobilinogen from 5-aminolaevulinic acid. The structure of the yeast enzyme has been solved to 2.3 A resolution, revealing that each subunit adopts a TIM barrel fold with a 39 residue N-terminal arm. Pairs of monomers wrap their arms around each other to form compact dimers and these associate to form a 422 symmetric octamer. All eight active sites are on the surface of the octamer and possess two lysine residues (210 and 263), one of which, Lys 263, forms a Schiff base link to the substrate. The two lysine side chains are close to two zinc binding sites one of which is formed by three cysteine residues (133, 135 and 143) while the other involves Cys 234 and His 142. ALAD has features at its active site that are common to both metallo- and Schiff base-aldolases and therefore represents an intriguing combination of both classes of enzyme. Lead ions, which inhibit ALAD potently, replace the zinc bound to the enzyme's unique triple-cysteine site.

A taxonomy of voice therapy

PURPOSE

Voice therapy practice and research, as in most types of rehabilitation, is currently limited by the lack of a taxonomy describing what occurs during a therapy session (with enough precision) to determine which techniques/components contribute most to treatment outcomes. To address this limitation, a classification system of voice therapy is proposed that integrates descriptions of therapeutic approaches from the clinical literature into a framework that includes relevant theoretical constructs.

METHOD

Literature searches identified existing rehabilitation taxonomies/therapy classification schemes to frame an initial taxonomic structure. An additional literature search and review of clinical documentation provided a comprehensive list of therapy tasks. The taxonomy's structure underwent several iterations to maximize accuracy, intuitive function, and theoretical underpinnings while minimizing redundancy. The taxonomy was then used to classify established voice therapy programs.

RESULTS

The taxonomy divided voice therapy into direct and indirect interventions delivered using extrinsic and/or intrinsic methods, and Venn diagrams depicted their overlapping nature. A dictionary was developed of the taxonomy's terms, and 7 established voice therapy programs were successfully classified.

CONCLUSION

The proposed taxonomy represents an important initial step toward a standardized voice therapy classification system expected to facilitate outcomes research and communication among clinical stakeholders.

Endoscopic laser foraminoplasty on the lumbar spine--early experience

Since April 1995 this endoscope assisted laser technique has been used for widening the lumbar exit route foramina. Patient selection included individuals with primarily unilateral sciatica as well as low back pain and referred buttock pain following various operative interventions. Endoscopic laser foraminoplasty (ELF) utilises an endoscope, a uniportal posterolateral approach and a side firing holmium laser probe. Under direct vision and within the protection of saline solution, epidural scarring, extruded and sequestrated disc protrusions and/or osteophytes are removed by holmium laser ablation. The patient is responsive and aware under neurolept analgesia and this ensures the protection and the integrity of the nerve root. A total of 219 such interventions has been performed up to January 1, 1997. The first 48 cases with a follow-up exceeding 12 months have been included in this preliminary review. Initial experience is encouraging. The ELF seems to provide another means of addressing sequelae of primary degenerative disorders as well as the common consequences of conventional spine surgery. ELF provides an alternative to minimal intervention fenestrectomy and open surgical undercutting for predominantly unisegmental and unilateral lateral recess stenosis and in selected cases it may prevent or delay the indication of spinal fusion.

Angiosarcoma of the liver in children

The clinico-pathological features of four cases of pediatric hepatic angiosarcomas are described. One case was initially diagnosed in infancy and underwent resection of a left-sided benign hemangioendothelioma of the liver. Further resection of a lesion in the right liver was followed by malignant transformation. Primary hepatic resection of the tumor was not possible in three other cases, and all received courses of chemotherapy without significant tumor shrinkage. One child underwent liver transplantation but died 4 months later of immunosuppression complications. The remaining three children died of disseminated malignancy. Histological verification of malignancy was difficult in three cases in which there was discrepancy between the rapid growth of the liver tumor and the microscopic features of benign hemangioendothelioma.

Helicobacter pylori infection in children: population-based age-specific prevalence and risk factors in a developing country

AIM

We estimated the prevalence, age of acquisition and risk factors for Helicobacter pylori (H. pylori) seroprevalence in children aged 1-15 years.

METHODS

Exposure was assessed using ELISA. Parents responded to a questionnaire regarding number of individuals sharing house, rooms, water source, latrines, housing and assessment of socioeconomic status (SES) by Hollingshead Index.

RESULTS

Serum of 1976 children was tested. Helicobacter pylori seropositivity in children aged 11-15 years was 53.5% (OR: 2.0, 95% CI: 1.58-2.5). It increased with moderate crowding index (CRI) of 2-4 to 45.9% (OR: 1.23, 95% CI: 0.92-1.63) and to 51.2% with CRI >4 (OR: 1.52, 95% CI: 1.12-2.06). In middle SES, seropositivity was 50.5% (331/655) (OR: 1.7, 95% CI: 1.29-2.35), whereas in lower SES, it was 47.1% (500/1062) (OR: 1.5, 95% CI: 1.1-2.0). Multivariate analysis showed that Helicobacter pylori seroprevalence was high in children aged 6-10 and 11-15 years (OR: 1.5, 95% CI: 1.2-1.9 and OR: 1.9, 95% CI: 1.56-2.47 respectively), in lower-middle SES (OR: 1.6, 95% CI: 1.2-2.1 and OR: 1.5, 95% CI: 1.10-2.0 respectively) and in uneducated fathers (OR: 1.58, 95% CI: 1.27-1.95).

CONCLUSION

Helicobacter pylori seropositivity increases with age, in low-middle SES and is related to father's educational status. Reducing H. pylori seroprevalence will require improvement in sanitary conditions and educational status of the population.

Helicobacter pylori: correlation of the virulence marker iceA allele with clinical outcome in a high prevalence area

The association of Helicobacter pylori virulence marker 'induced by contact with epithelium A' (iceA) allele types was determined in H. pylori-related diseases and virulence markers. Gastric biopsies were obtained at EGD from patients for culture, histopathology and polymerase chain reaction (PCR) for iceA types, cagA and vacA alleles. Two hundred and eighty-four H. pylori isolates were examined. iceA type 1 was positive in 177 (62%) and iceA type 2 in 158 (56%). In iceA type 2, gastric ulcer was present in 34 (21%) (P < 0.001) and carcinoma in 28 (25%) (P = 0.002), compared to nine (8%) and 2 (2%) in iceA type 2-negative cases. For iceA type 2, 139 (88%) were associated with chronic active gastritis compared to 95 (75%) (P = 0.006) in iceA type 2-negative. H. pylori cagA was positive in 101 (64%) iceA type 2 strains compared to 57 (45%) in negative strains (P = 0.002). H. pylori iceA type 2 was dominant and associated with cagA, chronic active inflammation, gastric ulcer and carcinoma.

Crystallization of 5-aminolaevulinic acid dehydratase from Escherichia coli and Saccharomyces cerevisiae and preliminary X-ray characterization of the crystals

5-Aminolaevulinic acid dehydratase (ALAD) catalyzes the formation of porphobilinogen from two molecules of 5-aminolaevulinic acid. Both Escherichia coli and Saccharomyces cerevisiae ALADs are homo-octameric enzymes which depend on Zn2+ for catalytic activity and are potently inhibited by lead ions. The E. coli enzyme crystallized in space group I422 (unit cell dimensions a = b = 130.7 A, c = 142.4 A). The best crystals were obtained in the presence of the covalently bound inhibitor laevulinic acid. The yeast enzyme (expressed in E. coli) crystallized in the same space group (I422) but with a smaller unit cell volume (a = b = 103.7 A, c = 167.7 A). High resolution synchrotron data sets were obtained from both E. coli and yeast ALAD crystals by cryocooling to 100 K.

ShcA promotes chondrocyte hypertrophic commitment and osteoarthritis in mice through RunX2 nuclear translocation and YAP1 inactivation

OBJECTIVE

Chondrocyte hypertrophic differentiation, a key process in endochondral ossification, is also a feature of osteoarthritis leading to cartilage destruction. Here we investigated the role of the adaptor protein Src homology and Collagen A (ShcA) in chondrocyte differentiation and osteoarthritis.

METHODS

Mice ablated for ShcA in osteochondroprogenitor cells were generated by crossing mice carrying the Twist2-Cre transgene with ShcA^flox/flox mice. Their phenotype (n = 5 to 14 mice per group) was characterized using histology, immuno-histology and western-blot. To identify the signaling mechanisms involved, in vitro experiments were conducted on wild type and ShcA deficient chondrocytes (isolated from n = 4 to 7 littermates) and the chondroprogenitor cell line ATDC5 (n = 4 independent experiments) using western-blot, cell fractionation and confocal microscopy.

RESULTS

Deletion of ShcA decreases the hypertrophic zone of the growth plate (median between group difference -11.37% [95% confidence interval -17.34 to -8.654]), alters the endochondral ossification process, and leads to dwarfism (3 months old male mice nose-to-anus length -1.48 cm [-1.860 to -1.190]). ShcA promotes ERK1/2 activation, nuclear translocation of RunX2, the master transcription factor for chondrocyte hypertrophy, while maintaining the Runx2 inhibitor, YAP1, in its cytosolic inactive form. This leads to hypertrophic commitment and expression of markers of hypertrophy, such as Collagen X. In addition, loss of ShcA protects from age-related osteoarthritis development in mice (2 years old mice OARSI score -6.67 [-14.25 to -4.000]).

CONCLUSION

This study reveals ShcA as a new player in the control of chondrocyte hypertrophic differentiation and its deletion slows down osteoarthritis development.

An 8- to 10-year review of the Rotaglide total knee replacement

Mobile-bearing knee arthroplasty (MBKA) is an alternative to fixed-bearing knee arthroplasty. This was a retrospective study of the Rotaglide Total Knee System. We present the results of the monitoring of 77 patients (85 knees) with a median duration to failure or end of follow up of 8.5 years (range 0.4 to 10.1 years). Patients were clinically and radiologically assessed at dedicated follow up clinics. The Hospital for Special Surgery (HSS) and Knee Society Score (KSS) systems were used to describe the clinical and radiological findings. The prosthesis had an estimated survival probability of 93.5% (standard error 3.4%) at 9 years. It is associated with good rates of patient satisfaction and high scores on the HSS and KSS systems. No knees were revised for aseptic loosening. This knee replacement has a survival rate equivalent to other prostheses. It is a safe and reliable prosthesis associated with good clinical outcome.

Phonation With a Variably Occluded Facemask: Effects of Task Duration

OBJECTIVE

Semioccluded vocal tract (SOVT) exercises are routinely included in many voice therapy programs because they have been shown to improve acoustic, aerodynamic, and patient-reported voice outcomes. One limitation of the traditional SOVT exercise is that the nature of phonation through straws or semioccluded oral postures allows only for single phoneme production. A variably occluded facemask (VOFM) allows for use of articulated connected speech beyond the production of single phonemes, while still providing occlusion and, presumably, the vocal efficiency benefits that arise from it. This study reports on the effect of time duration of phonation with a variably occluded facemask on voice outcomes in patients with voice disorders.

DESIGN

Prospective, randomized cohort study.

METHODS

Fifteen patients with voice disorders phonated for 5 minutes through a VOFM with diameter openings of 3.2, 6.4, and 9.6 mm. Acoustic and aerodynamic voice measures were collected before and after each occlusion trial. These results were compared to a historical patient group that received the same phonation training for 2 minutes.

RESULTS

Positive effect sizes were found for acoustic and aerodynamic improvements for all patients for at least one occlusion diameter. Effect sizes for aerodynamic outcomes were greater in the 5-minute conditions for both the 9.6- and 6.4-mm occlusions than the 2-minute condition. Effect sizes for acoustic outcomes were greater in the 5 minute than 2-minute trial for the 9.6- and 6.4-mm occlusion diameter, but greater in the 2 minute than 5-minute trial for 3.2-mm diameter.

DISCUSSION

This study provides evidence that all three occlusion sizes may elicit beneficial changes for different patients; however, 5 minutes of phonation into a facemask with end occlusion of 6.4-mm diameter results in improved acoustic and aerodynamic voice outcomes for many patients with voice disorders. Future studies should further explore phonatory physiologic changes of the VOFM in a larger sample of patients and translate effects into clinical treatment for patients with voice disorders.

Seroprevalence of hepatitis E and Helicobacter pylori in a low socioeconomic area of a metropolitan city in a developing country

This study aims to determine the prevalence of coinfection of H. pylori and hepatitis E virus (HEV) in the paediatric age group in an urban slum area of Karachi and identify risk factors associated with co-infection. Five hundred and forty children aged one to 15 years were investigated. Blood samples were collected and questionnaires completed on socio-demographic characteristics. Anti-H. pylori, HEV IgG and IgM antibodies were analysed by enzyme immunoassays (EIAs). The seroprevalence of H. pylori antibody was 47.2%, while that of HEV IgG and IgM was 14.4% and 2.4%, respectively. 12.4% exhibited seroprevalence for both H. pylori and HEV (IgG). In 67 (26%) cases positive for H. pylori IgG, HEV IgG positivity was also seen (P < 0.001). Only 13 (5%) positive for H. pylori were also positive for HEV IgM (P < 0.001). Only 11 (4%) HEV IgG-positive cases were H. pylori antibody-negative (P < 0.001). Hepatitis E virus was common in children who had access to municipal piped water (P = 0.025). H. pylori was common in children who used a non-flush toilet system (P < 0.001). Children exposed to H. pylori infection were also exposed to the risk of HEV.

Association of Helicobacter pylori and protozoal parasites in patients with chronic diarrhoea

Introduction An association of Helicobacter pylori and common protozoal parasites in patients with abdominal discomfort and chronic diarrhoea is unclear and may be pathological. Materials and methods One hundred and sixty-one patients with diarrhoea were compared to 114 age and sex matched controls. Stool samples were examined by microscopy and DNA extracted for PCR with specific primers for H. pylori and protozoal parasites Blastocystis sp., Entamoeba sp. (Entamoeba histolytica, Entamoeba dispar and Entamoeba moshkovskii) and Giardia duodenalis (G. duodenalis). Results There was a marked difference in the presence of parasites between patients and controls: no parasite 42/75%, one parasite 42/15%, two or more parasites 16/10%, respectively (p < 0.001). Patients with diarrhoea were more likely to be infected with Blastocystis sp (p < 0.001), E. histolytica (p = 0.027) and E moshkovskii (p = 0.003). There was no difference in the frequency of H. pylori (p = 0.528), G duodenalis (p = 0.697) or E dispar (p = 0.425). Thirty-three patients and 27 controls had H. pylori infection. Of these, 22 patients and 6 controls were infected with Blastocystis sp (p = 0.001), 6 patients and no controls were infected with E. histolytica (p = 0.02), whilst 7 patents and 9 controls were infected with E dispar (p = 0.292). Conclusion In this population, diarrhoea is linked to infection with Blastocystis sp, E. histolytica and E moshkoviskii. In H. pylori infection, diarrhoea is linked to Blastocystis sp and E. histolytica infection. These associations may be linked pathogenically.

Medical mortality in Pakistan: experience at a tertiary care hospital

AIM

To acquire systematic data on the causes of hospital mortality in Pakistan, a developing country with scant mortality records.

STUDY DESIGN

Retrospective review of death certificates and hospital charts of patients dying on general and specialty medical services at our hospital during one calendar year.

RESULTS

Of a total 10,590 admissions, 657 (6.2%) died in hospital. The deceased included 357 (54.4%) males and 299 (45.6%) females, with a collective median age of 63 years and mean length of stay 6.71 days (median 4 days, range 1-56 days). Primary cause of death was categorised as infectious (21.2%), pulmonary (17.2%), cancer related (15.7%), cardiovascular (12.6%), gastrointestinal and hepatic (10.8%), neurological (11.4%) and miscellaneous (11.1%). Within each category, the most common diagnoses were septicaemia (76.9% of infectious cases), pneumonia (55.7% of pulmonary cases), myocardial infarction (40.9% of cardiovascular), intracranial haemorrhage (37.3% of neurological), and cirrhosis (45.0% of gastrointestinal). There were multiple causes among malignant disorders with no single cause dominating. Patients with cardiovascular and pulmonary deaths tended to be older than the median age (p = 0.001), while patients with gastrointestinal and cancer related deaths tended to be younger than the median age (p = 0.001). Length of stay did not differ significantly among the various subgroups. About a quarter (26.4%) deaths occurred within 24 h of admission.

CONCLUSIONS

Infections, including septicaemia and pneumonia, are the leading causes of hospital mortality in our setting, followed by malignancy and cardiovascular causes. The overall mortality rate is comparable to published mortality data from other hospital settings.

Reasons for failure to quit: a cross-sectional survey of tobacco use in major cities in Pakistan

BACKGROUND

Tobacco dependence has been defined as a chronic relapsing disease. Around 5 million annual tobacco-related deaths have been reported worldwide. The majority of smokers want to quit but are not successful.

OBJECTIVES

To screen our population for tobacco use, gauge the baseline demographics of tobacco users and assess factors associated with failed attempts to quit.

METHODS

Free health camps supervised by a physician were held across two major cities of Pakistan. All consenting participants were administered a questionnaire and had their exhaled carbon monoxide (CO) levels measured.

RESULTS

Of 12 969 participants successfully enrolled, the mean age was 31.4 ± 10.0 years. More than three quarters were aged 20-40 years (n = 10 168, 78.4%). The overall average CO level was 12.0 ± 8.0 ppm. The majority of the participants wanted to quit, and nearly everyone had received advice about quitting. The majority had tried smoking cessation pharmacotherapy. Friends/peer pressure (n = 1554, 12%), anxiety (n = 681, 5.3%), tobacco dependence (n = 1965, 15.2%) and stress/mood changes (n = 390, 3.0%) were the most widely observed reasons for failure to quit in study participants.

CONCLUSION

The information provided by this study can guide the development of more targeted intervention programmes for smokers who wish to quit.

Parental knowledge and attitudes towards dental radiography for children

BACKGROUND

Radiographs are an essential part of most clinical dental examinations and diagnoses. The aim of the study was to assess the knowledge and attitudes of parents towards dental radiographs for their children.

METHODS

A 21-item questionnaire, covering parental level of radiation knowledge and socio-demographics was applied. Sliding scales were used to assess attitude towards dental radiographs.

RESULTS

There were 1467 questionnaires distributed between five primary schools in the Perth (Western Australia) metropolitan area, with 309 surveys (21%) returned for collection. Most parents displayed a low level of knowledge, but had a positive attitude towards dental radiographs. Parents with children who have previously had dental radiographs perceived dental radiographs as 'good', 'useful' and 'pleasant'. A higher level of education and parents with children who have previously had radiographs were significantly associated with a higher level of knowledge about dental radiography. Parents who had higher scores on questions assessing radiation knowledge were more likely to perceive dental radiographs as 'safe' and 'beneficial'.

CONCLUSIONS

Most parents have a positive attitude towards dental radiographs on their children. However, the majority of parents lack knowledge regarding dental radiography, especially regarding the risks involved.

[Quantitative diagnosis of hypernasality in cleft lip and palate patients by computerized nasal quality assessment]

In patients with cleft lip and palate (CLP), the assessment of velopharyngeal morphology and function and the quantitative analysis of perceptual consequences of velopharyngeal insufficiency are of major importance regarding the effective planning of velopharyngoplasties for speech improvement. The NasalView, a new instrument for the objective assessment of rhinophonia, is presented. The NasalView measures nasalance, the relative sound pressure level of the nasal signal in speech, expressed as a percentage. In order to evaluate the effectiveness of the computerised measurement of nasalance, 156 patients with surgically treated CLP were examined. The NasalView differentiated with high sensitivity and specificity between patients with normal nasal resonance and patients with varying degrees of hypernasality. To illustrate the importance of the NasalView for making the decision for a velopharyngoplasty, a single case is presented.

An unusual case of patella dislocation

Images

Giant intra-abdominal cyst in a 13-year-old girl

A case of a massive unilocular intra-abdominal cyst arising in a 13-year-old girl is presented. This appeared to be a foregut duplication cyst of gastric origin, and thus one of the largest recorded in the literature.

Clinician and Patient Perception of a Voice Therapy Program Utilizing a Variably Occluded Face Mask: A Pilot Study

OBJECTIVE

The purpose of this investigation was to assess clinician and patient feedback about voice therapy using a variably occluded face mask (VOFM) and to determine if voice therapy augmented via a VOFM would result in favorable changes in patient self-perceived handicap, as well as acoustic and aerodynamic measures.

METHODS/DESIGN

This pilot study used a prospective, pre-post single group design. Eleven patients with dysphonia due to primary muscle tension dysphonia (8) or benign vocal fold lesions (3) were recruited. Data collected included patient and clinician feedback of voice therapy using a VOFM, voice handicap index (VHI)-10, acoustic and aerodynamic measures. Data were collected before treatment (baseline) and 1-week post-therapy. Wilcoxon signed-rank tests were used to compare data pre- and post-therapy.

RESULTS

Statistically significant improvement was observed for the VHI-10 with a median delta of -7. Clinician feedback generally reported that patients liked the VOFM, using the VOFM within the first two sessions of therapy, and within less than 10 min of use. All clinicians ranked the conversation level of the hierarchy as the most effective level. Three themes emerged from the Therapy Feedback Form: the VOFM was a (1) "Facilitator for Sensation," (2) a "Physical Tool," and that there was (3) "No Program Needed" to use the VOFM in voice therapy. There was a statistically significant improvement in cepstral peak prominence (p = 0.0329) and cepstral spectral index of dysphonia (p = 0.0164) in sustained vowels.

DISCUSSION

This pilot study represents the first investigation into clinician and patient perceptions of using a VOFM. Reported measures via patient perception, as well as clinician perceptions, and some acoustic and aerodynamic measures showed that participants got better with VOFM voice therapy. Last, in general, both clinicians and patients liked utilizing a VOFM in voice therapy.