Utility of next-generation sequencing technologies for the efficient genetic resolution of haematological disorders

Next-generation sequencing (NGS) has now evolved to be a relatively affordable and efficient means of detecting genetic mutations. Whole genome sequencing (WGS) or whole exome sequencing (WES) offers the opportunity for rapid diagnosis in many paediatric haematological conditions, where phenotypes are variable and either a large number of genes are involved, or the genes are large making sanger sequencing expensive and labour-intensive. NGS offers the potential for gene discovery in patients who do not have mutations in currently known genes. This report shows how WES was used in the diagnosis of six paediatric haematology cases. In four cases (Diamond-Blackfan anaemia, congenital neutropenia (n = 2), and Fanconi anaemia), the diagnosis was suspected based on classical phenotype, and NGS confirmed those suspicions. Mutations in RPS19, ELANE and FANCD2 were found. The final two cases (MYH9 associated macrothrombocytopenia associated with multiple congenital anomalies; atypical juvenile myelomonocytic leukaemia associated with a KRAS mutation) highlight the utility of NGS where the diagnosis is less certain, or where there is an unusual phenotype. We discuss the advantages and limitations of NGS in the setting of these cases, and in haematological conditions more broadly, and discuss where NGS is most efficiently used.

Nicotine Absorption from Smokeless Tobacco Modified to Adjust pH

INTRODUCTION

Nicotine delivery from smokeless tobacco (ST) products leads to addiction and the use of ST causes pathology that is associated with increased initiation of cigarette smoking. The rapid delivery of nicotine from ST seems to be associated with the pH of the aqueous suspension of the products - high pH is associated with high nicotine absorption. However, early studies compared nicotine absorption from different commercial products that not only differed in pH but in flavoring, nicotine content, and in format-pouches and loose tobacco.

METHODS

The present study compared nicotine absorption from a single unflavored referent ST product (pH 7.7) that was flavored with a low level of wintergreen (2 mg/g) and the pH was amended to either high (8.3) or low (5.4) pH with sodium carbonate or citric acid, respectively.

RESULTS

In a within-subject clinical study, the higher pH products delivered more nicotine. No significant differences were seen between perceived product strengths and product experience in all conditions. Heart rate increased by 4 to 6 beats per minute after the high pH flavored and the un-amended product but did not change after the low pH flavored product.

CONCLUSIONS

These results indicate that pH is a primary determinant of buccal nicotine absorption. The role of flavoring and other components of ST products in nicotine absorption remain to be determined.

Understanding, compliance and psychological impact of the SARS quarantine experience

This study examines a cohort of persons quarantined during the 2003 SARS outbreak in Canada and describes their understanding of, difficulties and compliance with, and the psychological impact of the quarantine experience. A mailed questionnaire was administered to 1912 eligible adults and included the Impact of Events Scale - Revised (IES-R) to assess symptoms of post-traumatic stress disorder (PTSD). Self-reported compliance with all required quarantine measures was low (15.8+/-2.3%), although significantly higher when the rationale for quarantine was understood (P=0.018). Health-care workers (HCW) experienced greater psychological distress, including symptoms of PTSD (P<0.001). Increasing perceived difficulty with compliance, HCW, longer quarantine and compliance with quarantine requirements were significant contributors to higher IES-R scores. The low compliance with quarantine requirements introduces concerns about the effectiveness of quarantine as a public health measure. Improvements in compliance and reduced psychological distress may be possible by minimizing duration, revising requirements, and providing enhanced education and support.

The effects of medical group practice and physician payment methods on costs of care

OBJECTIVE

To assess the effects of payment methods on the costs of care in medical group practices.

DATA SOURCES

Eighty-six clinics providing services for a Blue Cross managed care program during 1995. The clinics were analyzed to determine the relationship between payment methods and cost of care. Cost and patient data were obtained from Blue Cross records, and medical group practice clinic data were obtained by a survey of those organizations.

STUDY DESIGN

The effects of clinic and physician payment methods on per member per year (PMPY) adjusted patient costs are evaluated using a two-stage regression model. Patient costs are adjusted for differences in payment schedules; patient age, gender, and ACG; clinic organizational variables are included as explanatory variables.

DATA COLLECTION

Patient cost data were extracted from Blue Cross claims files, and patient and physician data from their enrollee and provider data banks. Medical group practice data were obtained by a mailed survey with telephone follow-up.

PRINCIPAL FINDINGS

Capitation payment is correlated with lower patient care costs. When combined with fee-for-service with withhold provisions, this effect is smaller indicating that these two clinic payment methods are not interchangeable. Clinics with more physician compensation based on measures of resource use or based on some share of the net revenue of the clinic have lower patient care costs than those with more compensation related to productivity or based on salary. Salary compensation is strongly associated with higher costs. The use of physician profiles and clinical guidelines is associated with lower costs, but referral management systems have no such effect. The lower cost clinics are the smaller, multispecialty clinics.

CONCLUSIONS

This study indicates that payment methods at both the medical group practice and physician levels influence the cost of care. However, the methods by which that influence is manifest is not clear. Although the organizational structure of clinics and their use of managed care programs appear to play a role, this influence is less than expected.

Eye drops--the hidden poison

Eye drops are very commonly prescribed but their potential for systemic absorption and serious toxicity may be forgotten. This paper examines patterns of prescription of eye drops in Scotland by general practitioners. A review of the serious systemic features and toxicity, and their management, of commonly used eye drops is undertaken. Practical recommendations for the monitoring of such effects in clinical practice are made.

Dyspnea in ambulatory patients with SLE: prevalence, severity, and correlation with incremental exercise testing

OBJECTIVE

We sought to determine the prevalence and severity of dyspnea, and to correlate dyspnea with clinical features and exercise limitation in ambulatory patients with systemic lupus erythematosus (SLE).

METHODS

Twenty-five consecutive patients were evaluated with a validated pulmonary questionnaire, chest radiograph, 2-dimensional echocardiography, resting pulmonary function tests, and incremental exercise testing.

RESULTS

Dyspnea was reported by 60% (95% CI 39-79) of patients; 20% (95% CI 7-40) had severe dyspnea (inability to dress without dyspnea) and 12% (95% CI 3-31) had moderate dyspnea (dyspnea after walking 100 yards). Compared to patients without dyspnea, patients with dyspnea were more likely to have had a history of clinical lupus involving the lung (80 vs 40%, p = 0.05), a lower total lung capacity (77.5 vs 94.8%, p = 0.002), and a reduced maximum oxygen consumption (VO2max of 53.4 vs 67.7%, p = 0.01). Patients with severe dyspnea and patients without dyspnea did not differ in duration of prednisone use, activity of disease, weight, or in frequency of Raynaud's phenomenon (p > 0.05). Only 4% of all patients had abnormal left ventricular motion on 2-dimensional echo; patients with moderate or severe dyspnea had normal left ventricular motion. Of the 5 patients with severe dyspnea, 4 (80%) had restrictive lung disease and 1 (20%) had an isolated diffusion defect. All patients with dyspnea had an abnormal exercise test, but so did 9/10 without dyspnea (p > 0.05). Severity of dyspnea correlated highly with maximum exercise tolerance measured by VO2max (R2 = 0.51, p = 0.0001).

CONCLUSION

In ambulatory patients with SLE, dyspnea is common, frequently disabling, associated with a history of lupus involvement of the lung, and correlates highly with objective measures of exercise limitation.

Infective endocarditis in a dairy farmer in association with bovine Staphylococcus aureus mastitis

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Effects of chlorhexidine and four antimicrobial compounds on plaque, gingivitis, and staining in beagle dogs

Solutions containing 0.2% of a bis-biguanide, chlorhexidine (positive control), and four bis-amidinourea antimicrobial agents were tested in beagle dogs in a 12-week study. The five agents significantly reduced clinical plaque and gingivitis scores, and gingival fluid volumes in treated dogs, compared with water. All compounds reduced the stain area scores compared to water controls. Stain intensity scores were higher for chlorhexidine than for the four new antimicrobial agents and the water controls. There were no overt behavioral changes. Histological examination of oral tissues revealed no irritation.

Osteopoietin-humoral induction factor in osteogenesis

A heat-stable, glycoprotein-like material, osteopoietin, produced during bone marrow regeneration, has been shown to induce bone formation when implanted in the rat eye. The material was separated by ultrasonic treatment or by acid buffer (pH 3-5) from sponges implanted in the marrow. The extracted material free of bone or cell solids, induced bone formation in the anterior eye chamber of the rat, whereas the cell solids and control sponges similarly implanted did not.

The measurement of the effect of toothbrushes on soft tissue abrasion

The effect of toothbrushes on soft tissue abrasion was measured using hamster cheek pouch tissue brushed mechanically for various intervals. The detection of protein removed during brushing was used as an index of tissue abrasion. The method was found to be sensitive in detecting the effects of brush load, number of strokes applied, and the texture of the brush. The results further showed that the mechanical removal of sharp edges from bristle tips substantially reduced the level of soft tissue abrasion while a dentifrice polishing agent applied to the tissue with a brush did not increase the abrasive effect of the brush.

Production of levan and dextran in plaque in vivo

Frequent eating of small amounts of sucrose for a period of three days resulted in the in vivo accumulation in plaque of about 1% dextran and about 3% levan.

Dextranglucosidase activity in supragingival plaque

Enzyme activity was present in pooled dental plague that hydrolyzed dextran added to glucose. Hydrolysis of dextran occurred in the pH range of 5.15 to 7.1. Glucose released endogenously from plague alone was equivalent in amount to that released by amyloglucosidase; therefore, it was from starchy sources.