SMAD3 mutation in LDS3 causes bone fragility by impairing the TGF-β pathway and enhancing osteoclastogenesis

Loss-of-function mutations in SMAD3 cause Loeys-Dietz syndrome type 3 (LDS3), a rare autosomal-dominant connective tissue disorder characterized by vascular pathology and skeletal abnormalities. Dysregulation of TGF-β/SMAD signaling is associated with abnormal skeletal features and bone fragility. To date, histomorphometric and ultrastructural characteristics of bone with SMAD3 mutations have not been reported in humans and the exact mechanism by which SMAD3 mutations cause the LDS3 phenotype is poorly understood. Here, we investigated bone histomorphometry and matrix mineralization in human bone with a SMAD3 mutation and explored the associated cellular defect in the TGF-β/SMAD pathway in vitro. The index patient had recurrent fractures, mild facial dysmorphism, arachnodactyly, pectus excavatum, chest asymmetry and kyphoscoliosis. Bone histomorphometry revealed markedly reduced cortical thickness (−68 %), trabecular thickness (−32 %), bone formation rate (−50 %) and delayed mineralization. Quantitative backscattered electron imaging demonstrated undermineralized bone matrix with increased heterogeneity in mineralization. The patient's SMAD3 mutation (c.200 T > G; p.I67S), when expressed from plasmid vectors in HEK293 cells, showed reduced phosphorylation and transcription factor activity compared to normal control and SMAD3 (p.S264Y), a gain-of-function mutation, somatic mosaicism of which causes melorheostosis. Transfection study of the patients' SMAD3 (p.I67S) mutation displayed lower luciferase reporter activity than normal SMAD3 and reduced expression of TGF-β signaling target genes. Patient fibroblasts also demonstrated impaired SMAD3 protein stability. Osteoclastogenic differentiation significantly increased and osteoclast-associated genes, including ACP5 (encoding TRAP), ATP6V0D2, and DCSTAMP, were up-regulated in CD14 (+) peripheral blood mononuclear cells (PBMCs) with the SMAD3 (p.I67S) mutation. Upregulation of osteoclastogenic genes was associated with decreased expression of TGF-β signaling target genes. We conclude that bone with the SMAD3 (p.I67S) mutation features reduced bone formation, and our functional studies revealed decreased SMAD3 activation and protein stability as well as increased osteoclastogenesis. These findings enhance our understanding of the pathophysiology of LDS3 caused by SMAD3 mutations. Emerging therapies targeting in the TGF-β/SMAD pathway also raise hope for treatment of LDS3.

•

Increased bone fragility

•

Low bone matrix mineralization

•

SMAD3 (p.I67S) decreased TGF-b signaling and SMAD3 activity.

•

SMAD3 (p.I67S) reduced SMAD3 protein stability.

•

SMAD3 (p.I67S) mediated osteoclastogenesis.

DNA fragmentation of sperm: a radical examination of the contribution of oxidative stress and age in 16 945 semen samples

STUDY QUESTION

What is the relationship between sperm DNA fragmentation and oxidative stress (OS) with increasing male age?

SUMMARY ANSWER

Sperm DNA fragmentation increases with age and is likely related to both defective spermatogenesis and increasing OS levels.

WHAT IS KNOWN ALREADY

Sperm quality declines with age. The presence of DNA damage in a high fraction of spermatozoa from a raw semen sample is associated with lower male fertility in natural conception and intrauterine insemination.

STUDY DESIGN, SIZE, DURATION

A retrospective cohort study of 16 945 semen samples analysed at a single reference laboratory between January 2010 and December 2018.

PARTICIPANTS/MATERIALS, SETTING, METHODS

All males were undergoing an infertility evaluation. The cohort was divided into seven age categories: <30, 30-34, 35-39, 40-44, 45-49, 50 to <54 and ≥55 years. The mean age was 37.6 years (SD 6.8). Sperm DNA fragmentation index (DFI) and high DNA stainability (HDS) were calculated using flow cytometry. OS levels were measured using the oxidative stress adducts (OSA) test, by spectrophotometry. ANOVA with weighted polynomial contrast analysis was used to evaluate trends for DFI, OSA and HDS values across age categories.

MAIN RESULTS AND THE ROLE OF CHANCE

Mean DFI significantly increased across all age groups (Ptrend < 0.001). OSA was lowest in patients <30 years old (mean 3.6, SD 1.0) and also increased as age increased (Ptrend < 0.001). There was a statistically significant difference between age groups for each of the three parameters (P < 0.001). There was a significant linear trend for DFI, OSA and HDS across the seven age categories (P < 0.001). Among patients with high DFI, there was a decreasing age-dependent trend in the patients observed with high OSA (P < 0.001).

LIMITATIONS, REASONS FOR CAUTION

This is a retrospective study. All males included in the study were undergoing a work-up for infertility and may not be representative of a fertile population. Additional patient demographics and clinical data were not available.

WIDER IMPLICATIONS OF THE FINDINGS

DNA and/or oxidative damage in sperm may be just as important to understand as the chromosomal aberrations that are carried in the oocyte. Further studies are needed to evaluate the effect of advancing paternal age on the male genome and, ultimately, on the health of the offspring.

STUDY FUNDING/COMPETING INTEREST(S)

No funding was obtained for this study. V.D. is an employee of Reprosource/Quest Diagnostics. D.S. reports he was a Scientific Advisor to Cooper Surgical.

TRIAL REGISTRATION NUMBER

N/A.

Intrinsic predictors of prolonged length of stay in a colorectal enhanced recovery pathway: a prospective cohort study and multivariate analysis

AIM

This was a prospective cohort study to determine the intrinsic non-modifiable factors influencing length of stay (LOS) in unselected consecutive patients undergoing elective colorectal surgery within an enhanced recovery pathway.

METHODS

This study interrogated a prospective database of consecutive elective procedures from October 2006 to April 2011 at a tertiary referral academic hospital in the UK to identify independent predictors of prolonged length of stay (pLOS). pLOS was defined as longer than median length of stay (mLOS). Differences in determinants were identified in three groups of increasing operative complexity.

RESULTS

In all, 872 procedures were identified and ranged from a simple ileostomy reversal to complex total pelvic exenteration. Preoperative anaemia and American Society of Anesthesiologists (ASA) Grade III+ predicted pLOS in stoma reversal surgery patients (n = 191, mLOS 4 days). In colonic and small bowel surgery (n = 444, mLOS 8 days), an open procedure, new stoma formation, planned critical care admission and ASA III+ predicted pLOS. New stoma formation and planned critical care admission predicted pLOS in patients undergoing pelvic rectal surgery (n = 237, mLOS 11 days). pLOS was associated with significantly higher morbidity across Dindo-Clavien grades and a longer time to postoperative functional recovery and discharge.

CONCLUSIONS

Operative complexity is associated with longer LOS even with an established enhanced recovery pathway in place. Intrinsic non-modifiable predictors of pLOS differ with operative complexity, and this should be taken into account when planning benchmarking and research across units.

The cost of treating diabetic ketoacidosis in an adolescent population in the UK: a national survey of hospital resource use

AIMS

Adolescents with Type 1 diabetes commonly experience episodes of ketoacidosis. In 2014, we conducted a nationwide survey on the management of diabetic ketoacidosis in young people. The survey reported how individual adolescents with diabetes were managed. However, the costs of treating diabetic ketoacidosis were not reported.

METHODS

Using this mixed population sample of adolescents, we took a 'bottom-up' approach to cost analysis aiming to determine the total expense associated with treating diabetic ketoacidosis. The data were derived using the information from the national UK survey of 71 individuals, collected via questionnaires sent to specialist paediatric diabetes services in England and Wales.

RESULTS

Several assumptions had to be made when analysing the data because the initial survey collection tool was not designed with a health economic model in mind. The mean time to resolution of diabetic ketoacidosis was 15.0 h [95% confidence interval (CI) 13.2, 16.8] and the mean total length of stay was 2.4 days (95% CI 1.9, 3.0). Based on data for individuals and using the British Society of Paediatric Endocrinology and Diabetes (BSPED) guidelines, the cost analysis shows that for this cohort, the average cost for an episode of diabetic ketoacidosis was £1387 (95% CI 1120, 1653). Regression analysis showed a significant cost saving of £762 (95% CI 140, 1574; P = 0.04) among those treated using BSPED guidelines.

CONCLUSION

We have used a bottom-up approach to calculate the costs of an episode of diabetic ketoacidosis in adolescents. These data suggest that following treatment guidelines can significantly lower the costs for managing episodes of diabetic ketoacidosis.

Young people's experiences of managing Type 1 diabetes at university: a national study of UK university students

AIM

Little is known about the challenges of transitioning from school to university for young people with Type 1 diabetes. In a national survey, we investigated the impact of entering and attending university on diabetes self-care in students with Type 1 diabetes in all UK universities.

METHODS

Some 1865 current UK university students aged 18-24 years with Type 1 diabetes, were invited to complete a structured questionnaire. The association between demographic variables and diabetes variables was assessed using logistic regression models.

RESULTS

In total, 584 (31%) students from 64 hospitals and 37 university medical practices completed the questionnaire. Some 62% had maintained routine diabetes care with their home team, whereas 32% moved to the university provider. Since starting university, 63% reported harder diabetes management and 44% reported higher HbA_1c levels than before university. At university, 52% had frequent hypoglycaemia, 9.6% reported one or more episodes of severe hypoglycaemia and 26% experienced diabetes-related hospital admissions. Female students and those who changed healthcare provider were approximately twice as likely to report poor glycaemic control, emergency hospital admissions and frequent hypoglycaemia. Females were more likely than males to report stress [odds ratio (OR) 4.78, 95% confidence interval (CI) 3.19-7.16], illness (OR 3.48, 95% CI 2.06-5.87) and weight management issues (OR 3.19, 95% CI 1.99-5.11) as barriers to self-care. Despite these difficulties, 91% of respondents never or rarely contacted university support services about their diabetes.

CONCLUSION

The study quantifies the high level of risk experienced by students with Type 1 diabetes during the transition to university, in particular, female students and those moving to a new university healthcare provider.

The Alphabet Strategy and standards of care in young adults with type 1 diabetes

The Alphabet Strategy is a mnemonic-based approach to assist commitment to important aspects of diabetes care: Advice; Blood pressure lowering; Cholesterol and creatinine control; Diabetes control; Eye examination; Foot examination; and use of Guardian drugs. This strategy reported high standards of care of patients with type 2 diabetes. This study assesses the impact of the Alphabet Strategy on diabetes management in young adults with type 1 diabetes and compared data with those of a recently published multicentre study. Results were analysed using the chi-square test and Student's t-test.

Data were collected retrospectively from 68 patients with type 1 diabetes aged 16—25 years attending the George Eliot Hospital (GEH) adolescent diabetes clinic and who were being managed as per The Alphabet Strategy.

Standards of diabetes care in the GEH clinic were better than those reported in the multicentre study. GEH versus multicentre study: clinic non-attendance 12% vs. 24.6%: mean HbA1C% 8.4 vs. 9.5, p<0.001: screening rates; hypertension 100% vs. 88%, p<0.05; nephropathy 80% vs. 56%, p<0.01; retinopathy 98% in GEH clinic: prevalence of complications; nephropathy 5% vs. 21%, p<0.02; retinopathy 24% vs. 28%, not significant.

In conclusion, we found regular clinic visits and separate adolescent clinics improve glycaemic control. The Alphabet Strategy may be considered an effective approach in monitoring/screening and attaining targets in young adults with type 1 diabetes.

Systematic review of clinical outcomes after prophylactic surgery

Introduction Prophylactic appendicectomy is performed prior to military, polar and space expeditions to prevent acute appendicitis in the field. However, the risk-benefit ratio of prophylactic surgery is controversial. This study aimed to systematically review the evidence for prophylactic appendicectomy. It is supplemented by a clinical example of prophylactic surgery resulting in life-threatening complications. Methods A systematic review was performed using MEDLINE(®) and the Cochrane Central Register of Controlled Trials. Keyword variants of 'prophylaxis' and 'appendicectomy' were combined to identify potential papers for inclusion. Papers related to prophylactic appendicectomy risks and benefits were reviewed. Results Overall, 511 papers were identified, with 37 papers satisfying the inclusion criteria. Nine reported outcomes after incidental appendicectomy during concurrent surgical procedures. No papers focused explicitly on prophylactic appendicectomy in asymptomatic patients. The clinical example outlined acute obstruction secondary to adhesions from a prophylactic appendicectomy. Complications after elective appendicectomy versus the natural history of acute appendicitis in scenarios such as polar expeditions or covert operations suggest prophylactic appendicectomy may be appropriate prior to extreme situations. Nevertheless, the long-term risk of adhesion related complications render prophylactic appendicectomy feasible only when the short-term risk of acute appendicitis outweighs the long-term risks of surgery. Conclusions Prophylactic appendicectomy is rarely performed and not without risk. This is the first documented evidence of long-term complications following prophylactic appendicectomy. Surgery should be considered on an individual basis by balancing the risks of acute appendicitis in the field with the potential consequences of an otherwise unnecessary surgical procedure in a healthy patient.

Chromosome 6q24 transient neonatal diabetes mellitus and protein sensitive hyperinsulinaemic hypoglycaemia

AIM

We describe the novel clinical observation of protein induced hyperinsulinaemic hypoglycaemia following remission of transient neonatal diabetes mellitus (TNDM) in a patient with 6q24 methylation defect.

METHODS

A male infant of non-consanguineous Caucasian parents, born at 40 weeks of gestation with a birth weight of 3330 g (-0.55 standard deviation score) presented with hyperglycaemia in the first week of life and was diagnosed with 6q24 TNDM. At 22 months of age, he developed recurrent hypoglycaemic episodes. Controlled diagnostic fast, oral glucose tolerance test, protein loading test and mixed meal tolerance test were undertaken. Sequencing of ABCC8, KCNJ11, GLUD1 and HADH were performed.

RESULTS

Investigations suggested a diagnosis of protein sensitive hyperinsulinaemic hypoglycaemia with normal serum ammonia, acylcarnitine profile and urine organic acids. Sequencing of ABCC8, KCNJ11, GLUD1 and HADH did not identify a pathogenic mutation to explain his hyperinsulinaemic hypoglycaemia.

CONCLUSION

This clinical case demonstrates the novel observation of protein sensitive hyperinsulinaemic hypoglycaemia in a patient with 6q24 TNDM. Long-term follow-up of patients with chromosome 6q24 TNDM is warranted following remission.

Mutational analysis of the adaptor protein 2 sigma subunit (AP2S1) gene: search for autosomal dominant hypocalcemia type 3 (ADH3)

CONTEXT

Autosomal dominant hypocalcemia (ADH) types 1 and 2 are due to calcium-sensing receptor (CASR) and G-protein subunit-α11 (GNA11) gain-of-function mutations, respectively, whereas CASR and GNA11 loss-of-function mutations result in familial hypocalciuric hypercalcemia (FHH) types 1 and 2, respectively. Loss-of-function mutations of adaptor protein-2 sigma subunit (AP2σ 2), encoded by AP2S1, cause FHH3, and we therefore sought for gain-of-function AP2S1 mutations that may cause an additional form of ADH, which we designated ADH3.

OBJECTIVE

The objective of the study was to investigate the hypothesis that gain-of-function AP2S1 mutations may cause ADH3.

DESIGN

The sample size required for the detection of at least one mutation with a greater than 95% likelihood was determined by binomial probability analysis. Nineteen patients (including six familial cases) with hypocalcemia in association with low or normal serum PTH concentrations, consistent with ADH, but who did not have CASR or GNA11 mutations, were ascertained. Leukocyte DNA was used for sequence and copy number variation analysis of AP2S1.

RESULTS

Binomial probability analysis, using the assumption that AP2S1 mutations would occur in hypocalcemic patients at a prevalence of 20%, which is observed in FHH patients without CASR or GNA11 mutations, indicated that the likelihood of detecting at least one AP2S1 mutation was greater than 95% and greater than 98% in sample sizes of 14 and 19 hypocalcemic patients, respectively. AP2S1 mutations and copy number variations were not detected in the 19 hypocalcemic patients.

CONCLUSION

The absence of AP2S1 abnormalities in hypocalcemic patients, suggests that ADH3 may not occur or otherwise represents a rare hypocalcemic disorder.

Lipoatrophy with insulin analogues in type I diabetes

Lipoatrophy is a rare complication of treatment with insulin analogues. It has been reported with insulin Lispro (Eli Lilly, Indianapolis, Indiana, USA) and insulin Glargine (Sanofi-Aventis, Paris, France). To our knowledge, this is one of the first reports of lipoatrophy with Aspart, biphasic Aspart and Detemir insulin analogues (Novo Nordisk, Bagsvaerd, Denmark). We report the cases of four children with type I diabetes who were commenced on NovoMix 30 or NovoRapid/Levemir insulin injections. They developed lipoatrophy at the injection sites after 2-3 years of treatment. In two of our patients, lipoatrophy resolved when the injection sites were changed, suggesting that local factors could be the cause of lipoatrophy. However, lipoatrophy developed at the new sites in the other two patients, requiring a change of insulin preparation. Regular examination of the injection sites facilitated early detection of lipoatrophy in our patients. Lipoatrophy completely resolved over 1-2 years in all patients with no recurrence after 3-4 years of follow-up.

Neonatal abstinence syndrome

Intrauterine exposure to drugs by mothers is not an uncommon finding ine our society. Due to the mother's suppression of a medical history, the diagnosis of neonatal abstinence syndrome is often missed. We report a case of a term, female, newborn, who presented with the following features;e restlessness, inconsolable crying, along with sweating, vigorous sucking; andadiarrhoea. No conclusion was derived from routine investigations. Eventually, with a high degree of suspicion regarding maternal drug addiction, her history was reviewed and it was discovered that the mother was a heroin addict. The baby was diagnosed as a case of Neonatal Abstinence Syndrome. The neonate was successfully managed thereafter and discharged.

Objective assessment comparing hand-assisted and conventional laparoscopic surgery

BACKGROUND

Although several reports have subjectively highlighted the benefits of hand-assisted as compared with conventional laparoscopic surgery, there has been little objective analysis comparing these two techniques.

METHODS

For this study, 12 trained laparoscopic surgeons completed standardized knot-tying and dissection tasks in a laparoscopic trainer using both hand-assisted (HandPort) and traditional laparoscopic techniques. Motion analysis with the Imperial College Surgical Assessment Device was used to assess performance, measuring the number of movements made, the path length of hand travel, and the time taken. Mann-Whitney U tests were used to compare hand-assisted (HA) and conventional laparoscopic (L) performance. A p value less than 0.05 was deemed significant. Means and standard deviations are shown in the results.

RESULTS

In knot tying, for both the dominant and nondominant hands, hand-assisted rather than conventional laparoscopic techniques resulted in reduced movements (dominant: HA [114 +/- 50] vs L [321 +/- 118, p < 0.001], nondominant: HA [89 +/- 36] vs L [296 +/- 96, p < 0.001]); path length (dominant: HA [1,083 +/- 680 mm] vs L [3,637 +/- 1,852 mm, p < 0.001], nondominant: HA [549 +/- 339 mm] vs L [2,556 +/- 1,042 mm, p < 0.001]); and time taken (HA [162 +/- 50 s] vs L [460 +/- 179 s, p < 0.001]). However, there was no statistical difference for any measured variable with respect to the dissection task.

CONCLUSION

Hand-assisted surgery significantly improves the knot-tying ability among trained laparoscopic surgeons. However, there appears to be no improvement in performance for this specific dissection task.

Technical skills examination for general surgical trainees

BACKGROUND

The technical skills of surgical trainees are difficult to assess and compare objectively. This study involved a structured, multistation, technical skills examination that enables the stratification of surgical trainees.

METHODS

Twenty-two surgeons (five basic surgical trainees, eight junior specialist trainees, four senior specialist trainees and five consultants) participated in the study. All undertook a five-station technical skills examination consisting of three synthetic simulations (bowel anastomosis, vascular anastomosis, saphenofemoral dissection) and two virtual reality-based (flexible sigmoidoscopy and laparoscopy) assessment stations. Video-based analyses and in-built computer scoring were used to measure each surgeon's performance. The mean rank was determined for each variable, and the sum of the mean ranks produced a total score.

RESULTS

There was a significant improvement in overall performance with increasing seniority (P<0.001). Significant differences were observed between basic surgical trainees and junior specialist trainees (P=0.019), and between junior and senior specialist trainees (P=0.048), but not between senior trainees and consultants.

CONCLUSION

This examination successfully differentiated surgical skill, both between surgeons with different grades of experience and within the target study group of specialist trainees. The examination is feasible in terms of the timeframe needed to complete tasks, cost, and efficiency in performing video-based assessments.

Graves' disease in DiGeorge syndrome: patient report with a review of endocrine autoimmunity associated with 22q11.2 deletion

DiGeorge syndrome, which falls within a wider phenotypic spectrum associated with deletions of 22q11.2, is associated with a number of endocrine disorders. These include hypoparathyroidism, hypothyroidism and growth hormone deficiency. We report an unusual case of autoimmune hyperthyroidism (Graves' disease) presenting in a 3 year-old male with DiGeorge syndrome. The development of endocrine specific autoimmune disease in a syndrome associated with immune deficiency and the spectrum of endocrine autoimmunity associated with deletions of 22q11.2 are described. Paediatricians and patients with 22q11.2 deletions should be particularly aware of the risks of developing disorders of thyroid function.

Qualitative and quantitative analysis of the learning curve of a simulated surgical task on the da Vinci system

BACKGROUND

Robotic telemanipulation systems provide solutions to the problems of less dexterity and visual constraints of minimally invasive surgery (MIS). However, their influence over surgeons' dexterity and learning curve needs to be assessed. We present motion analysis as an objective method to measure performance and learning progress.METHODS. Thirteen surgeons completed five synthetic small bowel anastomoses using the da Vinci system. Objective Structured Assessment of Technical Skills (OSATS) allowed qualitative analysis. Quantitative analysis used API software of the system to retrieve real-time robotic signal data of time, path length, and number of movements. Wilcoxon signed ranks test was used for statistical analysis. A p value <0.05 was considered significant.RESULTS. OSATS global scores were 18.6 points for the first attempt and 26 for the fifth attempt ( p < 0.02, Cronbach's alpha = 0.894). Paired data of motion analysis for attempts 1 vs 5 showed significant change: time taken 3507 sec and 2287 sec ( p < 0.008), total number of movements 2411 and 1387 ( p = 0.01), total path length 21,630 cm and 13,941 cm ( p = 0.01).CONCLUSIONS. A rapid learning curve to a competent level using the da Vinci system is possible aided by the system's intuitive motion. Motion analysis is a useful tool to measure performance in the da Vinci system compared to OSATS and time alone.

Suppression of TSH in congenital hypothyroidism is significantly related to serum levels and dosage of thyroxine

AIM

To assess thyrotropin (thyroid-stimulating hormone; TSH) suppression and serum thyroxine (T(4)) concentrations in infants with congenital hypothyroidism in relation to T(4) dose and pretreatment parameters.

METHOD

A retrospective study of all cases treated in a single centre since neonatal screening began was performed.

RESULTS

In 54 infants treated with a mean daily T(4) dose of 9.8 microg/kg, the TSH concentration was suppressed (<6 mU/l) in 65% of the cases by 6 months with the serum T(4) level at the upper end of the infant reference range. Infants who suppressed their TSH later did not differ in pretreatment serum TSH or T(4) concentration. T(4) dose and serum T(4) level were lower in infants whose TSH was not suppressed.

CONCLUSIONS

TSH suppression in congenital hypothyroidism is significantly related to serum levels and dosage of T(4). We suggest that a delay in TSH suppression is mainly due to undertreatment.

The PreOp flexible sigmoidoscopy trainer. Validation and early evaluation of a virtual reality based system

AIM

To demonstrate face and construct validity of a computer based flexible sigmoidoscopy trainer.

METHODS

The PreOp (Immersion Medical, USA) system is a virtual reality based flexible sigmoidoscopy simulator. The system records several performance parameters, such as percentage of colonic mucosa visualized, time taken, and pathlength of endoscope travel. Forty-five subjects were divided into three groups: novice (never performed a lower GI endoscopy), intermediate (5-50 examinations), and trained (greater than 200 examinations). After initial familiarization subjects were assessed three times on a case module. Results showed a nonparametric distribution.

RESULTS

There was a significant difference between all three groups with respect to percentage of mucosa visualized (novice 71.0 +/- 3.7%, intermediate 77.3 +/- 5.6%, expert 84.8 +/- 4.6%, Kruskal-Wallis p <0.001) and efficiency ratio (%mucosa/time, novice 0.163 +/- 0.055, intermediate 0.259 +/- 0.07, expert 0.306 +/- 0.058, p <0.001). The novice group was also slower and had a lower pathlength of instrument travel compared to the others.

CONCLUSION

PreOp virtual reality simulator is a valid discriminator of flexible sigmoidoscopic experience. Its effect on training needs to be explored.

Practice distribution in procedural skills training: a randomized controlled trial

BACKGROUND

"Massed" and "distributed" practice are important concepts in the acquisition of fine motor skills, and may be important in training in procedural skills.

METHODS

A total of 41 novice subjects were recruited and randomized to three groups to receive training on the MIST VR surgical trainer. There were 14 subjects in each of groups A and B and 13 subjects in group C. Training comprised 20 min of massed practice for group A, 20 min of distributed practice in 5 min blocks for group B, and 15 min of distributed practice in 5-min blocks for group C. Following the training period, all groups had a 5-min rest period, followed by a 5-min retention test. Comparisons were made between groups A and B, and groups A and C.

RESULTS

There was a statistically significant difference between groups A and B (p = 0.023) on the retention test, with group B performing better. The increment between the groups was 19% for the overall score on MIST VR. There were also significant differences in the time taken to complete the task during the training phase (p = 0.023, training blocks 3 and 4). Graphical representation suggests no effect between groups A and C, and statistical analysis confirms that the observed difference in median score is not significant.

CONCLUSION

This study demonstrates a benefit for distributed practice over massed practice in learning laparoscopic surgical skills on the MIST VR surgical trainer. This finding has potential implications for skills training in all areas of medicine.

Maternal knowledge, attitude and practices towards diarrhea and oral rehydration therapy in rural Maharashtra

OBJECTIVE

A cross sectional hospital based survey was undertaken in rural area of Wardha District of Maharashtra, to assess the knowledge, attitude and practices of mothers regarding diarrhea and oral rehydration therapy.

METHODS

75 mothers of under-five children participated [corrected] in the study. They were interviewed by an interviewer using a pre-designed and pre-tested questionnaire.

RESULTS

69.3% of them had a per-capita income of less than rupees 500 [corrected]. 68% of mothers knew the correct definition of diarrhea but only 5.3% of them were aware that diarrhea leads to dehydration [corrected]. 90.7% of mothers were aware of ORT and ORS was easily available to the majority, but only 60% of mothers [corrected] practiced ORT. Nearly 1/3rd of mothers were mixing ORS in the wrong fluid. Nearly half of the mothers were not practicing adequate hand washing, 32% were using feeding bottles [corrected].

CONCLUSION

The maternal knowledge towards diarrhea and ORS was inadequate in the population studied [corrected] and there was a big gap between actual and desired practices.

The use of electromagnetic motion tracking analysis to objectively measure open surgical skill in the laboratory-based model

BACKGROUND

Technical performance has traditionally been assessed subjectively within the operating theater, with few successful attempts at objective analysis. The Imperial College Surgical Assessment Device (ICSAD) has already been shown to be a valid quantitative measure of dexterity in laparoscopic surgical simulation. We describe its application to the assessment of open surgical procedures.

STUDY DESIGN

Fifty-one participants were recruited from four different levels of general surgical experience: basic surgical trainees (n = 12), junior specialist registrars (n = 13), senior specialist registrars (n = 13), and consultants (n = 13). They completed two tasks: a small bowel anastomosis and a vein patch insertion into an artery. Surgical performance was measured with the Imperial College Surgical Assessment Device, a motion analysis system that measures the number of hand movements made and time taken to complete a task. The four groups were compared statistically using the Kruskal-Wallis test (K-W). Pairwise group comparisons used the Mann-Whitney U test and p values were adjusted for multiple comparisons to determine the statistical significance of these comparisons.

RESULTS

Mean values for number of movements and time (secs) for small bowel anastomosis were 2,080/1,236 (basic surgical trainees), 1,673/1,016 (junior specialist registrars), 1,375/862 (senior specialist registrars), and 1,337/782 (consultants), respectively. Comparison of the medians by K-W revealed a p < 0.001 for each variable (No. of movements, time), respectively. Mean vein patch insertion results were 1,653/1,258, 1,297/1,006, 1,090/912, and 925/736 for each of the four groups. Again, comparison of the medians by K-W revealed a p < 0.001 for each variable.

CONCLUSIONS

These findings suggest that hand motion analysis may be an effective objective measure of dexterity in open surgical simulation.

Hyperinsulinism in short-chain L-3-hydroxyacyl-CoA dehydrogenase deficiency reveals the importance of beta-oxidation in insulin secretion

A female infant of nonconsanguineous Indian parents presented at 4 months with a hypoglycemic convulsion. Further episodes of hypoketotic hypoglycemia were associated with inappropriately elevated plasma insulin concentrations. However, unlike other children with hyperinsulinism, this patient had a persistently elevated blood spot hydroxybutyrylcarnitine concentration when fed, as well as when fasted. Measurement of the activity of L-3-hydroxyacyl-CoA dehydrogenase in cultured skin fibroblasts with acetoacetyl-CoA substrate showed reduced activity. In fibroblast mitochondria, the activity was less than 5% that of controls. Sequencing of the short-chain L-3-hydroxyacyl-CoA dehydrogenase (SCHAD) genomic DNA from the fibroblasts showed a homozygous mutation (C773T) changing proline to leucine at amino acid 258. Analysis of blood from the parents showed they were heterozygous for this mutation. Western blot studies showed undetectable levels of immunoreactive SCHAD protein in the child's fibroblasts. Expression studies showed that the P258L enzyme had no catalytic activity. We conclude that C773T is a disease-causing SCHAD mutation. This is the first defect in fatty acid beta-oxidation that has been associated with hyperinsulinism and raises interesting questions about the ways in which changes in fatty acid and ketone body metabolism modulate insulin secretion by the beta cell. The patient's hyperinsulinism was easily controlled with diazoxide and chlorothiazide.