Bridging the gaps: recent advances in diagnosis, care, and outcomes in congenital hyperinsulinism

PURPOSE OF REVIEW

To highlight advances in congenital hyperinsulinism (HI), including newly described molecular mechanisms of disease, novel therapeutic interventions, and improved understanding of long-term outcomes.

RECENT FINDINGS

Important advances have been made elucidating the molecular mechanisms responsible for HI. Non-coding variants in HK1 have been found to cause aberrant hexokinase expression. Inactivating mutations in SLC25A36 have been identified in children with features of the hyperinsulinism hyperammonemia syndrome. Low-level mosaic mutations in known HI genes have been detected in cases of 'genetic testing negative' HI. Identification and localization of focal HI lesions remains a priority, since focal HI can be cured with surgery. Use of 68 Ga-NODAGA-exendin-4 PET has been proposed to localize focal lesions. Additional studies are needed before this technique replaces 18 F-DOPA PET as standard of care. Treatment options for children with diffuse HI remain limited. The long-acting somatostatin analog, lanreotide, was shown to significantly improve glycemic control in a large series of children with HI. New therapies are under development, with promising preliminary results. Long-term quality of life and neurodevelopmental outcomes remain suboptimal.

SUMMARY

Advanced genetic and epigenomic analytic techniques have uncovered novel molecular mechanisms of HI. Development of new drugs holds promise to improve long-term outcomes for individuals with HI.

Using Automated Speech Processing for Repeated Measurements in a Clinical Setting of the Behavioral Variability in the Stroop Task

The Stroop interference task is indispensable to current neuropsychological practice. Despite this, it is limited in its potential for repeated administration, its sensitivity and its demands on professionals and their clients. We evaluated a digital Stroop deployed using a smart device. Spoken responses were timed using automated speech recognition. Participants included adult nonpatients (N = 113; k = 5 sessions over 5 days) and patients with psychiatric diagnoses (N = 85; k = 3-4 sessions per week over 4 weeks). Traditional interference (difference in response time between color incongruent words vs. color neutral words; M = 0.121 s) and facilitation (neutral vs. color congruent words; M = 0.085 s) effects were robust and temporally stable over testing sessions (ICCs 0.50-0.86). The performance showed little relation to clinical symptoms for a two-week window for either nonpatients or patients but was related to self-reported concentration at the time of testing for both groups. Performance was also related to treatment outcomes in patients. The duration of response word utterances was longer in patients than in nonpatients. Measures of intra-individual variability showed promise for understanding clinical state and treatment outcome but were less temporally stable than measures based solely on average response time latency. This framework of remote assessment using speech processing technology enables the fine-grained longitudinal charting of cognition and verbal behavior. However, at present, there is a problematic lower limit to the absolute size of the effects that can be examined when using voice in such a brief 'out-of-the-laboratory condition' given the temporal resolution of the speech-to-text detection system (in this case, 10 ms). This resolution will limit the parsing of meaningful effect sizes.

Undiagnosed hypoglycaemia disorders in children detected when hypoglycaemia occurs in the setting of illness: a retrospective study

OBJECTIVE

Whether hypoglycaemia incidentally detected during intercurrent illness in children requires an endocrine workup remains controversial. This study aimed to determine the yield of conducting a diagnostic evaluation in this setting and to compare clinical and biochemical features between patients ultimately diagnosed with a hypoglycaemic disorder and those who were not.

DESIGN

Single-center, retrospective review of children referred to endocrinology between January 2013 and December 2018 for evaluation of hypoglycaemia (defined as plasma glucose<3.9 mmol/L (<70 mg/dL)) in the setting of acute illness.

RESULTS

145 patients met eligibility criteria. A hypoglycaemia disorder was identified in 12 patients (8% of the cohort, 17% of those who underwent a diagnostic fast). There were no cases in which diagnosis was established in the absence of a diagnostic fast. Characteristics associated with identifying an underlying disorder included younger age (1.03 years (IQR: 0.05-1.54) vs 2.18 years [IQR: 1.29-3.99], p<0.001), higher bicarbonate level (22±5.5 mmol/L vs 16±3.6 mmol/L, p<0.001), lower frequency of elevated plasma or urine ketones (25% vs 92%, p=0.004) and lower frequency of other documented medical problems (17% vs 50%, p=0.03).

CONCLUSIONS

The yield of diagnostic evaluation among children with incidental detection of hypoglycaemia in the setting of illness is not insignificant. We thus recommend that all children with hypoglycaemia in the setting of illness undergo guided diagnostic evaluation. Younger age and absence of ketosis and acidosis at presentation may serve as useful predictors for establishing a diagnosis. Future studies are needed to confirm these findings.

Mosaic GLUD1 Mutations Associated with Hyperinsulinism Hyperammonemia Syndrome

INTRODUCTION

The hyperinsulinemia-hyperammonemia syndrome (HIHA) is the second most common cause of congenital hyperinsulinism and is caused by activating heterozygous missense mutations in GLUD1. In the majority of HIHA cases, the GLUD1 mutation is found to be de novo. We have identified 3 patients in whom clinical evaluation was suggestive of HIHA but with negative mutation analysis in peripheral blood DNA for GLUD1 as well as other known HI genes.

METHODS

We performed next-generation sequencing (NGS) on peripheral blood DNA from two children with clinical features of HIHA in order to look for mosaic mutations in GLUD1. Pancreas tissue was also available in one of these cases for NGS. In addition, NGS was performed on peripheral blood DNA from a woman with a history of HI in infancy whose child had HIHA due to a presumed de novo GLUD1 mutation.

RESULTS

Mosaic GLUD1 mutations were identified in these 3 cases at percent mosaicism ranging from 2.7% to 10.4% in peripheral blood. In one case with pancreas tissue available, the mosaic GLUD1 mutation was present at 17.9% and 28.9% in different sections of the pancreas. Two unique GLUD1 mutations were identified in these cases, both of which have been previously reported (c.1493c>t/p.Ser445Leu and c.820c>t/p.Arg221Cys).

CONCLUSION

The results suggest that low-level mosaic mutations in known HI genes may be the underlying molecular mechanism in some children with HI who have negative genetic testing in peripheral blood DNA.

The earliest known reported occurrence of dentigerous cyst in a six-month-old child

The earliest reported case of the occurrence of a dentigerous cyst is described; the cyst surrounded an unerupted permanent tooth bud in a 6-month-old infant. Most commonly these lesions present between the second and third decades of life. They rarely occur before 10 years of age and have not been documented prior to 1 year of age. In the case reported here, the treatment instituted was extraction of the adjacent deciduous tooth and enucleation of the cyst along with the permanent molar tooth bud. Clinicians should be aware of the potential for this lesion to occur across a wide range of ages and the importance of prompt diagnosis and treatment to prevent complications and reduce morbidity.

Characterizing the neurological phenotype of the hyperinsulinism hyperammonemia syndrome

BACKGROUND

Hyperinsulinism hyperammonemia (HI/HA) syndrome is caused by activating mutations in GLUD1, encoding glutamate dehydrogenase (GDH). Atypical absence seizures and neuropsychological disorders occur at high rates in this form of hyperinsulinism. Dysregulated central nervous system (CNS) glutamate balance, due to GDH overactivity in the brain, has been hypothesized to play a role. This study aimed to describe the neurologic phenotype in HI/HA syndrome and investigate CNS glutamate levels using glutamate weighted chemical exchange saturation transfer magnetic resonance imaging (GluCEST MRI). In this cross-sectional study, 12 subjects with HI/HA syndrome had plasma ammonia measurement, self- or parent-completed neurocognitive assessments, electroencephalogram (EEG), and GluCEST MRI at 7 T performed. GluCEST MRI measures were compared to a historic reference population of 10 healthy adults.

RESULTS

Subjects were five males and seven females with median age of 25.5 years. Seventy-five percent of subjects reported a history of neurodevelopmental problems and 42% had neurocognitive assessment scores outside the normal range. Fifty percent had interictal EEG findings of generalized, irregular spike and wave discharges. Higher variability in hippocampal GluCEST asymmetry (p = 0.002), and in peak hippocampal GluCEST values (p = 0.008), was observed in HI/HA subjects (n = 9 with interpretable MRI) compared to the healthy reference population (n = 10).

CONCLUSIONS

The high prevalence of abnormal neurocognitive assessment scores and interictal EEG findings observed highlights the importance of longitudinal neuropsychological assessment for individuals with HI/HA syndrome. Our findings demonstrate the potential application of GluCEST to investigate persistent knowledge gaps in the mechanisms underlying the unique neurophenotype of this disorder.

Incidence and risk factors for hypoglycemia during maintenance chemotherapy in pediatric acute lymphoblastic leukemia

BACKGROUND

Fasting hypoglycemia is a recognized occurrence among pediatric patients with acute lymphoblastic leukemia (ALL) during maintenance therapy. Existing publications describing this finding are limited to small studies and case reports. Our objective was to determine the incidence of hypoglycemia during maintenance chemotherapy and to investigate the association of age, as well as other potential risk factors, with this outcome in pediatric patients with ALL.

PROCEDURE

This retrospective cohort study included individuals 1 to 21 years of age with ALL treated with antimetabolite-containing maintenance chemotherapy at a large children's hospital between January 2011 and December 2014. The primary endpoint was time to first documented episode of hypoglycemia during maintenance therapy, defined as single measurement of plasma glucose <60 mg/dL. Cox regression was used to evaluate the association with age and identify other potential risk factors.

RESULTS

We identified 126 eligible patients, of whom 63% were documented as White, non-Hispanic, 28% as non-White, non-Hispanic, and 9% as Hispanic. Twenty-eight children (22%) had documented hypoglycemia during maintenance therapy. Younger age at the start of maintenance and hepatotoxicity documented during chemotherapy prior to maintenance initiation were associated with hypoglycemia (adjusted HR age = 0.88; 95% CI, 0.78-0.99; adjusted HR prior hepatotoxicity = 3.50; 95% CI, 1.47-8.36).

CONCLUSIONS

Nearly one quarter of children in our cohort had hypoglycemia documented during maintenance chemotherapy. Younger age at maintenance initiation and hepatotoxicity during chemotherapy prior to maintenance initiation emerged as risk factors. These findings highlight the importance of counseling about the risk of, and monitoring for, hypoglycemia, particularly in young children.

Case Report: Two Distinct Focal Congenital Hyperinsulinism Lesions Resulting From Separate Genetic Events

Focal hyperinsulinism (HI) comprises nearly 50% of all surgically treated HI cases and is cured if the focal lesion can be completely resected. Pre-operative localization of the lesion is thus critical. Few cases of hyperinsulinism with multiple focal lesions have been reported, and assessment of the molecular mechanisms driving this rare occurrence has been limited. We present two cases of multifocal HI, each resulting from two independent, pancreatic focal lesions. ¹⁸Fluoro-dihydroxyphenylalanine positron emission tomography/computed tomography detected both lesions preoperatively in one patient, whereas identification of the second lesion was an incidental finding during surgical exploration in the other. Complete resection of the focal lesions resulted in cure of the HI in both cases. In each patient, genetic testing of the individual focal lesions revealed different regions of loss of heterozygosity for the maternal 11p15 allele, confirming that each lesion arose from independent somatic events in the setting of a paternally inherited germline ABCC8 mutation. These cases highlight the importance of a multidisciplinary and personalized approach to the management of infants with HI.

MON-110 Utilization of GluCEST, a Novel Neuroimaging Technique, to Characterize the Brain Phenotype in Hyperinsulinism/Hyperammonemia Syndrome

BACKGROUND: Hyperinsulinism/Hyperammonemia (HI/HA) syndrome is the second most common form of congenital hyperinsulinism. It is caused by gain-of-function mutations in glutamate dehydrogenase (GDH), a mitochondrial enzyme expressed in pancreatic β-cells, liver, kidney, and brain, and is responsible for metabolizing glutamate into α-ketoglutarate and ammonia. In addition to hyperinsulinemic hypoglycemia due to abnormal GDH activity in pancreatic β-cells, ~80% of patients have developmental delays, learning, or behavioral disorders and &gt;60% have atypical absence seizures (Bahi-Buisson, 2008). These neurologic symptoms are not fully explained by hypoglycemia and are hypothesized to result from central nervous system (CNS) glutamate imbalance due to CNS GDH overactivity. Newer magnetic resonance imaging (MRI) techniques have allowed for sensitive estimation of CNS glutamate using Glutamate Chemical Exchange Saturation Transfer (GluCEST). We aimed to comprehensively characterize the biochemical and clinical neurologic phenotype of HI/HA leveraging GluCEST MRI.

Methods: Subjects with confirmed HI/HA diagnosis and without contraindication to MRI had electroencephalogram (EEG), serum ammonia, and the following validated neurodevelopmental assessments: ABAS-3, BRIEF, and ASEBA CBCL (if &lt;18 years) or ASR (if &gt;18 years) completed. GluCEST MRI axial hippocampal and midsagittal slices were acquired on a 7.0T Siemens scanner and reported as GluCEST % contrast. Healthy control GluCEST % contrast data were obtained from a separate study using the same neuroimaging protocol.

Results: 8 HI/HA subjects (4 female; mean age 28 years [range 16-56] years) participated to date. Median serum ammonia was 58 umol/L (IQR 39-89). 50% self-reported learning impairments and 37.5% self-reported prior ADHD diagnosis. Marked unilateral increase in hippocampal GluCEST % contrast was observed in 3/6 subjects (2 L&gt;R; 1 R&gt;L). Overall, median peak GluCEST % contrast level was significantly higher in HI/HA subjects than controls (10.3% [IQR 8.9-11.3] v. 8.0% [IQR 7.8-8.4], p=0.0013, n=6).

Conclusions: This is the first study to evaluate CNS glutamate via GluCEST in HI/HA. Hippocampal glutamate, measured by GluCEST % contrast, was significantly higher in HI/HA subjects than healthy controls. Laterality in hippocampal glutamate was observed in half of subjects. These findings are remarkable given the known role of abnormal glutamate signaling in the development of epilepsy and neurocognitive impairment. Next steps are to complete midsagittal GluCEST image processing, EEG and neurodevelopmental assessment interpretations to explore correlations between CNS phenotype and brain glutamate pattern. GluCEST holds promise for elucidating the pathophysiology of CNS manifestations in HI/HA syndrome.

Single-Spin Magnetomechanics with Levitated Micromagnets

We demonstrate a new mechanical transduction platform for individual spin qubits. In our approach, single micromagnets are trapped using a type-II superconductor in proximity of spin qubits, enabling direct magnetic coupling between the two systems. Controlling the distance between the magnet and the superconductor during cooldown, we demonstrate three-dimensional trapping with quality factors around 1×10^{6} and kHz trapping frequencies. We further exploit the large magnetic moment to mass ratio of this mechanical oscillator to couple its motion to the spin degrees of freedom of an individual nitrogen vacancy center in diamond. Our approach provides a new path towards interfacing individual spin qubits with mechanical motion for testing quantum mechanics with mesoscopic objects, realization of quantum networks, and ultrasensitive metrology.

Initial Safety and Tumor Control Results From a "First-in-Human" Multicenter Prospective Trial Evaluating a Novel Alpha-Emitting Radionuclide for the Treatment of Locally Advanced Recurrent Squamous Cell Carcinomas of the Skin and Head and Neck

PURPOSE

Our purpose was to report the feasibility and safety of diffusing alpha-emitter radiation therapy (DaRT), which entails the interstitial implantation of a novel alpha-emitting brachytherapy source, for the treatment of locally advanced and recurrent squamous cancers of the skin and head and neck.

METHODS AND MATERIALS

This prospective first-in-human, multicenter clinical study evaluated 31 lesions in 28 patients. The primary objective was to determine the feasibility and safety of this approach, and the secondary objectives were to evaluate the initial tumor response and local progression-free survival. Eligibility criteria included all patients with biopsy-proven squamous cancers of the skin and head and neck with either primary tumors or recurrent/previously treated disease by either surgery or prior external beam radiation therapy; 13 of 31 lesions (42%) had received prior radiation therapy. Toxicity was evaluated according to the Common Terminology Criteria for Adverse Events version 4.03. Tumor response was assessed at 30 to 45 days at a follow-up visit using the Response Evaluation Criteria in Solid Tumors, version 1.1. Median follow-up time was 6.7 months.

RESULTS

Acute toxicity included mostly local pain and erythema at the implantation site followed by swelling and mild skin ulceration. For pain and grade 2 skin ulcerations, 90% of patients had resolution within 3 to 5 weeks. Complete response to the Ra-224 DaRT treatment was observed in 22 lesions (22/28; 78.6%); 6 lesions (6/28, 21.4%) manifested a partial response (>30% tumor reduction). Among the 22 lesions with a complete response, 5 (22%) developed a subsequent local relapse at the site of DaRT implantation at a median time of 4.9 months (range, 2.43-5.52 months). The 1-year local progression-free survival probability at the implanted site was 44% overall (confidence interval [CI], 20.3%-64.3%) and 60% (95% CI, 28.61%-81.35%) for complete responders. Overall survival rates at 12 months post-DaRT implantation were 75% (95% CI, 46.14%-89.99%) among all patients and 93% (95% CI, 59.08%-98.96%) among complete responders.

CONCLUSIONS

Alpha-emitter brachytherapy using DaRT achieved significant tumor responses without grade 3 or higher toxicities observed. Longer follow-up observations and larger studies are underway to validate these findings.

Psychiatric Risk Assessment from the Clinician's Perspective: Lessons for the Future

Accurate prediction of risk-states in Serious Mental Illnesses (SMIs) is critical for reducing their massive societal burden. Risk-state assessments are notably inaccurate. Recent innovations, including widely available and inexpensive mobile technologies for ambulatory "biobehavioral" data, can reshape risk assessment. To help understand and accelerate clinician involvement, we surveyed 90 multi-disciplinary clinicians serving SMI populations in various settings to evaluate how risk assessment is conducted and can improve. Clinicians reported considerable variability in conducting risk assessment, and few clinicians explicated their procedures beyond tying it to broader mental status examinations or interviews. Very few clinicians endorsed using currently-available standardized risk measures, and most reported low confidence in their utility. Clinicians also reported spending approximately half the time conducting individual risk assessments than optimally needed. When asked about improvement, virtually no clinicians acknowledged biobehavioral, objective technologies, or ambulatory recording. Overall, clinicians seemed unaware of meaningful ways to improve risk assessment.

Congenital hyperinsulinism disorders: Genetic and clinical characteristics

Congenital hyperinsulinism (HI) is the most frequent cause of persistent hypoglycemia in infants and children. Delays in diagnosis and initiation of appropriate treatment contribute to a high risk of neurocognitive impairment. HI represents a heterogeneous group of disorders characterized by dysregulated insulin secretion by the pancreatic beta cells, which in utero, may result in somatic overgrowth. There are at least nine known monogenic forms of HI as well as several syndromic forms. Molecular diagnosis allows for prediction of responsiveness to medical treatment and likelihood of surgically-curable focal hyperinsulinism. Timely genetic mutation analysis has thus become standard of care. However, despite significant advances in our understanding of the molecular basis of this disorder, the number of patients without an identified genetic diagnosis remains high, suggesting that there are likely additional genetic loci that have yet to be discovered.

Moving psychological assessment out of the controlled laboratory setting: Practical challenges

Behavioral assessment using smart devices affords novel methods, notably remote self-administration by the individuals themselves. However, this new approach requires navigating complex legal and technical terrain. Given the limited empirical data that currently exists, we provide and discuss anecdotes of the methodological, technical, legal, and cultural issues associated with an implementation in both U.S. and European settings of a mobile software application for regular psychological monitoring purposes. The tasks required participants to listen, watch, speak, and touch to interact with the smart device, thus assessing cognition, motor skill, and language. Four major findings merit mention: First, moving assessment out of the hands of a trained investigator necessitates excellent usability engineering, such that the tool is easily usable by the participant and the resulting data relevant to the investigator. Second, remote assessment requires that the data are transferred safely back to the investigator, and that risk of compromising participant confidentiality is minimized. Third, frequent data collection over long periods of time is associated with a possibility that participants may choose to withdraw consent for participation thus requiring data retraction. Fourth, data collection and analysis across international borders creates new challenges and new opportunities because of important cultural and language issues that may inform the underlying behavioral constructs of interest. In conclusion, the new technological frameworks provide unprecedented opportunities for remote self-administered behavioral assessments but will be most productive in multidisciplinary teams to ensure the highest level of user satisfaction and data quality, and to guarantee the highest level of data protection. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

OR05-2 Targeted Inhibition of Glutamate Dehydrogenase by Alpha-Tocopherol: A Potential Novel Treatment for Hyperinsulinism Hyperammonemia Syndrome

Congenital hyperinsulinism is a rare genetic disorder that causes severe hypoglycemia and can lead to permanent brain damage if inadequately controlled. Gain of function mutations in glutamate dehydrogenase (GDH) result in hyperinsulinism hyperammonemia (HI/HA) syndrome, the second most common cause of congenital hyperinsulinism. Current therapies inhibit insulin secretion but do not target GDH overactivity directly and thus fail to treat the spectrum of clinical manifestations observed, which in addition to hyperinsulinism and hyperammonemia, include seizures and developmental delays. The neurological symptoms are profound and occur independent of the hypoglycemia. We investigated the efficacy of alpha-tocopherol as a targeted GDH inhibitor in vitro and in vivo models of HI/HA syndrome. Human embryonic kidney (HEK293T) cells were transduced with lentivirus to overexpress either wild-type GDH or H454Y GDH, a well-characterized disease-causing mutant. GDH enzyme kinetics were determined spectrophotometrically in cell homogenates perfused with escalating concentrations of alpha-tocopherol on a background of 10mM glutamine. To evaluate the inhibitory effect of alpha-tocopherol on GDH in vivo, wild-type (WT, n=10) and H454Y GDH transgenic (Tg, n=13) adult mice were treated with oral alpha-tocopherol (75 μg/g body weight/dose) or vehicle twice daily for 3 doses and then fasted for 6 hours. Nadir fasting plasma glucoses were measured as a clinical correlate of GDH activity and compared between alpha-tocopherol and vehicle-treated wild-type and transgenic mice, respectively. Alpha-tocopherol effectively inhibited activity of wild-type and H454Y mutant GDH in HEK293T cells with 50% inhibitory concentration (IC50) of 4.1 and 3.1 μM, respectively. In vivo, nadir fasting plasma glucose was significantly higher in alpha-tocopherol-treated versus vehicle-treated WT and Tg mice (WT: mean nadir plasma glucose 94.3 ± 9.6 mg/dl v. 80.1 ± 9.6 mg/dl, p=0.003; Tg: mean nadir plasma glucose 71.9± 11.3 mg/dl v. 57.2 ± 12.6 mg/dl, p=0.002). Alpha-tocopherol effectively inhibits GDH in vitro and ameliorates fasting hypoglycemia in vivo in a mouse model of HI/HA syndrome. Based upon these findings, alpha-tocopherol is a promising potential treatment for HI/HA syndrome. Our next step will be to study the safety and efficacy of oral alpha-tocopherol supplementation in human subjects with HI/HA syndrome.

[Bone augmentation of the extremely atrophic anterior mandible, using allogeneic block grafts, via submental approach]

Edentulous patients with advanced resorption of the mandible (atrophic mandible) suffer major discomfort when using dentures. Furthermore, placing dental implants is impossible due to lack of sufficient bone volume. In the past, several methods of bone grafting to the anterior mandible have been proposed. Most of them were unpredictable in either the short or long-term. In 2002 a technique for bone grafting of the anterior mandible via a submental approach was published. A wide reflection of the soft tissue was followed by implant placement. Autogenous particulate posterior iliac crest bone graft was used. The presence of the implants did not allow for contraction of the soft tissue and bone resorption. The addition of bone volume to the chin improved the facial aesthetics of the patients due to a fuller appearance of the chin and tightening of the skin of the neck. The submental approach changes the spatial orientation of the surgeon and placement of implants in the correct location and angle become challenging. Placement of the implants too far buccally was a prosthetic problem. A major disadvantage of autogenous bone grafting is the necessity to operate a donor site. The increasing experience in use of allogenic bone grafts with resorbable collagen membranes, allowed us to modify the submental approach for bone grafting of the anterior atrophic mandible, avoiding a donor site surgery. We chose to perform the bone graft as a first stage surgery, in which, via a submental approach allogenic bone blocks were adapted and fixated to the anterior mandible with titanium screws, xenograft and resorbable collagen membranes were used. A few months (>4) were allowed for graft consolidation and then a second stage surgery was performed, via an intraoral approach dental implants were placed. In this way we avoided loss of orientation and had a familiar setting for implant location and angulation. Five patients with atrophic mandibles were treated using this surgical protocol. Based on cone beam CT imaging, average bone height in the anterior mandible prior to treatment was 5.52 mm. After bone graft, the average gain in bone height was 12.74 mm. No major post-operative complications were noted. After bone graft consolidation, 4 or 5 dental implants were placed, most of the implants used were longer than 11.5 mm. 22 implants were placed, out of which 21 integrated (95.5%). Some of the patients were rehabilitated with overdentures and locators and some with PFM bridges. All patients were followed up for more than a year and no implant failure was recorded. Bone grafting to the anterior mandible using allogenic blocks with collagen membranes via a submental approach with second stage implant placement seems to be a viable solution for rehabilitation of the atrophic mandible.

How perfect are you with defective probes? Information on the results of the mini-trial on technical quality assurance during the "Ultraschall 2012" conference in Davos

This article deals with the technical quality assurance of ultrasound B-systems. As part of a mini-trial during the Dreiländertreffen in Davos "Ultrasound 2012", we addressed the question as to whether physicians can detect faulty probes spontaneously during live scanning B-mode. For this purpose a special diagnostic device had been prepared so that groups of piezoelectric elements in the array were without function. Then the images had to be characterized by test persons without knowledge of the faulty elements. The results show that a deterioration of the image could be detected starting at five disabled elements. Due to the small number of test persons, our statements are only preliminary.

Investigation of the suitability of tissue phantoms for testing the constancy of ultrasonic transducer arrays in quality assurance

PURPOSE

To ensure high quality ultrasound diagnostics, proper functioning of the devices used is a necessary prerequisite. Ultrasound transducers have proven to be the most failure-prone part of the signal chain. Their technical monitoring is possible in principle with the help of tissue phantoms. The background of the present study is to determine which type of phantoms and which measurement parameters are best suited to a consistency test as part of routine quality assurance of ultrasound imaging systems.

MATERIALS AND METHODS

A classic wire-type phantom (ATS Mod. 539, ATS Labs Bridgeport, USA) and a 3 D cyst phantom (TCC, Timelkam, Austria) were used for the studies and comparative tests were conducted between intact transducers and those in which faults had been simulated. The collected measurement data show a relatively large scatter. Therefore, statistical analysis methods were used, and the discrimination analysis proved to be a useful tool.

RESULTS

Local failures which arise, e. g. due to the breakdown of individual piezoelectric elements or element groups in the transducer array, can be detected with the help of the gray value targets of the ATS phantom, but only in those cases in which the error-affected sound field part actually overlaps with the target under consideration. The TCC phantom is not suitable for the detection of such errors. Global transducer failures, i. e. those that affect the entire array, can even be detected with both types of phantoms.

CONCLUSION

When the emphasis of quality assessment is on the detection of local defects in the array that make up the largest part of the transducer faults, studies with conventional phantoms are only of limited value.

Physical activity and gestational weight gain: a meta-analysis of intervention trials

BACKGROUND

high gestational weight gain (GWG) has been found to be associated with a number of adverse perinatal and long-term outcomes.

OBJECTIVES

we aimed to perform a systematic review and meta-analysis to find out whether physical activity in pregnancy might help avoid high GWG.

SEARCH STRATEGY

a literature search in relevant databases and an additional search by hand through bibliographies of various publications were performed.

SELECTION CRITERIA

we included randomised controlled trials on healthy women, with increased physical activity as the only intervention. GWG had to be documented for the intervention and control group separately.

DATA COLLECTION AND ANALYSIS

two reviewers independently extracted data and performed quality assessment. Data from the included trials were combined using a random-effects model. The effect size was expressed as mean difference (MD).

MAIN RESULTS

of 1380 studies identified, 12 trials met the inclusion criteria. In seven trials, GWG was lower in the exercise group compared with the control group, whereas five trials showed a lower GWG in the control groups. The meta-analysis resulted in an MD of GWG of -0.61 (95% CI: -1.17, -0.06), suggesting less GWG in the intervention groups compared with the control groups. We found no indication for publication bias or dose effects.

AUTHOR'S CONCLUSIONS

in summary, our analyses suggest that physical activity during pregnancy might be successful in restricting GWG.

High yield expression of biologically active recombinant full length human tuftelin protein in baculovirus-infected insect cells

Tuftelin is an acidic protein expressed at very early stages of mouse odontogenesis. It was suggested to play a role during epithelial-mesenchymal interactions, and later, when enamel formation commences, to be involved in enamel mineralization. Tuftelin was also detected in several normal soft tissues of different origins and some of their corresponding cancerous tissues. Tuftelin is expressed in low quantities, and undergoes degradation in the enamel extracellular matrix. To investigate the structure and function of tuftelin, the full length recombinant human tuftelin protein was produced. The full length human tuftelin cDNA was cloned using Gateway recombination into the Bac-to-Bac system compatible transfer vector pDest10. This vector adds a hexahistidine tag to the N-terminus of the expressed protein, enabling one-step affinity purification on nickel column. The recombinant human tuftelin protein was transposed into the bacmid and expressed in Spodoptera frugiperda (Sf9) insect cells. The yield of the purified, his-tagged recombinant full length human Tuftelin (rHTuft+) was 5-8 mg/L culture. rHTuft+ was characterized by SDS-PAGE, Western blot, ESI-TOF spectrometry, restriction mapping and MS/MS sequencing. The availability of the purified, full length recombinant human tuftelin protein opened up the possibility to investigate novel functions of tuftelin. Application of rHTuft+ agarose beads onto embryonic mouse mandibular explants caused changes in the surrounding epithelial cells, including morphology, orientation and spatial organization. Further studies using DiI labeling, revealed that rHTuft+, placed on the tooth germ region, brought about recruitment of adjacent embryonic mesenchymal cells. These findings support the hypothesis that tuftelin plays an important role during embryogenesis.

Anaerobic cells of Bacillus cereus F4430/73 respond to low oxidoreduction potential by metabolic readjustments and activation of enterotoxin expression

In the present study, a food-borne pathogen strain of Bacillus cereus (F4430/73) was anaerobically grown in controlled-batch conditions under low initial oxidoreduction potential (ORP=-148 mV) using hydrogen gas as reducing agent. Its physiological characteristics, including growth, glucose fermentation capacity and enterotoxin production, were compared with anaerobic conditions generated by nitrogen gas (ORP=+ 45 mV). The results showed that low ORP affected growth mainly during the early stages. Maximal specific rates of growth and glucose consumption were reduced, and drastic changes in time profiles of fermentation product concentration were observed. Production of lactate was promoted at the expense of acetate. Nevertheless, low ORP did not affect final biomass yield. Under both ORP conditions, Non-haemolytic enterotoxin (Nhe) was produced early during the exponential growth phase as a first enterotoxin and Haemolysin BL (Hbl) later during the early stationary growth phase as a second enterotoxin. The major effect of low ORP was the strong stimulation of Hbl production and, to a lesser extent, Nhe production. This control was complex, involving different levels of regulation. We discussed the regulation of enterotoxin expression and the involvement of the pleiotropic regulator PlcR.

The human tuftelin gene and the expression of tuftelin in mineralizing and nonmineralizing tissues

Tuftelin has been suggested to play an important role during the development and mineralization of enamel, but its precise function is still unclear. This article reviews major milestones in the discovery, structural characterization, expression, localization, and conservation of tuftelin in different vertebrate species. It focuses on the structure of the human tuftelin gene, which has recently been deciphered [12]. It describes the exon-intron organization, sizes and structure, the promoter structure, and the newly discovered alternatively spliced human tooth-bud tuftelin mRNA transcripts. It also examines information on the structural motifs in the human-derived tuftelin protein and how they relate to tuftelin from other species. It reviews our recent results on the transcription of tuftelin mRNA and protein expression in several nonmineralizing soft tissues, using reverse-transcription polymerase chain reaction (RT-PCR) followed by DNA cloning and sequencing, indirect immunohistochemistry, immunohistochemistry combined with confocal microscopy, and in situ hybridization. These results and earlier Northern blot results show that tuftelin, in addition to being expressed in the developing and mineralizing tooth, is also expressed in several nonmineralizing soft tissues, suggesting that tuftelin has a universal function and/or a multifunctional role.

[Non-thermal non-cavitational effects of ultrasound]

The non-thermal, non-cavitational (NTNC-) effects of medical ultrasound are based essentially on the direct and indirect effects of the sound radiation pressure. This article introduces the biophysics of the basic mechanisms and describes possible clinical implications using selected examples. It has been determined that generally no additional risks ensue through the effects of NTNC used purely for diagnostic purposes. Significant effects can only be detected under the conditions which prevail during therapeutic exposure. The question as to whether the pulse Doppler technique is completely harmless cannot be answered conclusively at this time. The synergetic effects between ultrasound and contrast media have not yet been examined thoroughly.

Diabetes complications and risk factors in an Australian population. How well are they managed?

BACKGROUND

This study aimed to explore the relationship between complications and risk factors in the type 2 diabetes population, and to assess the level of assistance people with diabetes receive in controlling their risk factors.

METHODS

Participants were recruited from representative population surveys of South Australians aged over 18 years. Participants were asked a series of questions about their risk factors and the advice and assistance they received from their general practitioner (GP) in modifying their risk factors. Additionally, participants were clinically tested for a number of macro and microvascular complications.

RESULTS

South Australians with type 2 diabetes have a high prevalence of risk factors, with the majority being overweight or obese, doing no vigorous exercise and having high blood pressure. They also have a high prevalence of complications, with 53% having at least one macrovascular complication and 66% having at least one microvascular complication. Additionally, participants reported high levels of GP advice and assistance on the risk factors where pharmacological controls were available, but low levels of assistance where non-pharmacological interventions were needed to control the risk factor.

CONCLUSIONS

The prevalence of diabetes risk factors and complications among South Australians with type 2 diabetes is a cause for concern, as is the lack of assistance offered by GPs to modify risk factors. Multi-disciplinary approaches to the control of risk factors and patient self-management and education are critical to the progression and success of diabetes care.

Prospects for smoking cessation among people with insulin-dependent diabetes

As part of an initiative to develop a smoking cessation resource tailored to the needs of smokers with diabetes, we undertook a survey of 223 people with insulin-dependent diabetes (IDDM) aged 15-40 years, 54 of whom were smokers. Smokers had high levels of awareness that smoking increases the risk of heart and peripheral vascular disease, but were less aware of the risk of microvascular complications. Nearly half of the smokers had other members of the household who were smokers, and 56% indicated they would expect to receive no more than a little encouragement from friends and family members to quit. Concern about weight gain and dietary adherence was a barrier to quitting smoking for approximately one-third of smokers. Seventy percent of smokers recalled advice to quit smoking from a general practitioner, but this most often had involved minimal advice to quit. There is scope for patient education with respect to microvascular complications exacerbated by smoking, and a need to consider the smoking habits of other household members and enlist their active support for smoking cessation.

Visualization of the reaction layer in the immediate membrane vicinity

Coupled processes of diffusion and chemical reaction are quantitatively analyzed by means of proton concentration profile measurements in the immediate membrane vicinity. Because mass transfer across the unstirred layer (USL) is thought to proceed via diffusion, only the size of the USL is used as a scale for diffusion restrictions. Limitations associated with the finiteness of the reaction rate are characterized by the size of the reaction layer (RL). The latter is defined as the distance from the membrane where equilibrium is reached if transmembrane diffusion is followed by chemical reactions proceeding in the solution layers adjacent to the membrane. The well-known reaction of acetaldehyde oxidation catalyzed by alcohol dehydrogenase in the presence of NADH was selected because it is accompanied by an easily measurable alkalinization of the solution. The enzyme/coenzyme and the substrate were added to opposite sides of the membrane. A theoretical model describing the reaction and diffusion kinetics enabled us to calculate the size of the RL from the pH profile within the USL of a planar bilayer membrane showing a high proton permeability. As the enzyme concentration increased, the initially reaction-limited kinetics of the total turnover became diffusion limited under our experimental conditions due to a dramatic shortening of the RL.

Large outbreak of pertussis among young children in Chicago, 1993: investigation of potential contributing factors and estimation of vaccine effectiveness

BACKGROUND

An outbreak of pertussis from July, 1993, to April, 1994, in Chicago was investigated to identify potential contributing factors.

METHODS

Surveillance was enhanced to identify cases. Information from a vaccination coverage survey was used to define a retrospective cohort to estimate vaccine effectiveness of three or more doses of pertussis vaccine.

RESULTS

The median age of 218 reported cases was 8 months, 46% had Hispanic surnames and cases were clustered geographically. Vaccination status was known for 173 of 191 (91%) children younger than 6 years of age. Of these 173, 90 (52%) were younger than 7 months, and 35 (20%) children at least 7 months of age had received fewer than 3 doses of pertussis vaccine. Pertussis vaccine effectiveness was 76% (95% confidence interval, 29 to 92).

CONCLUSIONS

The limited ability of the current pertussis vaccination schedule to protect young infants accounted for 52% of cases, primary vaccine failure accounted for 28% of cases and failure to vaccinate children on time accounted for 20% of cases in young children. Low vaccine effectiveness did not appear to be a contributing factor.

Potential in vitro activity of Kutapressin against Epstein-Barr virus

BACKGROUND

Kutapressin (KU), a porcine liver extract with bradykinin-potentiating effects but no vitamin B 12 activity, has been used in the treatment of Herpes zoster. We examined a phenol-free preparation of this drug for in vitro activity against Epstein-Barr Virus (EBV).

MATERIALS AND METHODS

Immortalization-inhibition assays were used to assess EBV infectivity. Mitogen stimulation and cell viability assays were used to assess kutapression toxicity. Lytic replication assays and flow cytometry were used to assess the mechanism of drug activity.

RESULTS

Seventy-five hundred mcg/ml of KU blocked the infection of 2 x 10(5) human umbilical cord mononuclear cells when added together with two strains of EBV (B95-8 and FF41). Doses as low as 250 mcg/ml were occasionally effective as well. Unlike acyclovir, KU does not inhibit viral DNA polymerase nor does it appear to compete with EBV as it binds to its receptor on the B-cell surface.

CONCLUSIONS

The mechanism whereby KU may inhibit EBV immortalization remains to be determined. KU, a drug which is safe in humans, deserves further study as an agent with potential to block EBV-induced immortalization of B-lymphocytes.

Effect of ultrasound on the pH profiles in the unstirred layers near planar bilayer lipid membranes measured by microelectrodes

A pH shift in the unstirred layers (USLs) near a planar lipid bilayer membrane was induced by the diffusion of acetic acid along a concentration gradient. By means of a microelectrode technique it was shown that ultrasound decreases the thickness of the USL and that this reduction was much more pronounced on the side facing the ultrasound transducer than on the opposite side of the membrane. The effect depending on sound frequency and pressure is caused by the unidirectional fluid flow built up between transducer surface and membrane, the so-called quartz wind. Theoretical considerations based on the equations of the acoustic streaming near interfaces combined with the diffusion equation allow to predict the thickness of the USL if the sound field parameters are known.

Effects of ultrasound on the steady-state transmembrane pH gradient and the permeability of acetic acid through bilayer lipid membranes

The irradiation of bilayer lipid membranes with continuous ultrasound of a frequency of 8.2 MHz and a spacial peak time average (SPTA) intensity of 0.4 W/cm2 reduces the thickness of the unstirred layer up to 40% of its initial value under our conditions. This result was obtained from measurements of the transmembrane potential which appears after the addition of a protonophore in the presence of a gradient of acetic acid. Ultrasound exposure decreases this potential when the pH of the buffer solutions is much higher than the pK of CH3COOH and has no effect at low pH values. The latter can be explained by a simultaneous increase of the permeability of acetic acid and the buffer substances, respectively, due to ultrasound irradiation.

[Meningeal myelomatosis. Presentation of a case]

The case of a 36-year old man with IgA kappa multiple myeloma in whom meningeal myelomatosis developed is reported, and a brief review of previously published cases is made. Meningeal involvement develops in patients with high tumoral mass myeloma. Because of its poor prognosis, central nervous system chemoprophylaxis based on clinical and cerebrospinal fluid data, and systemic treatment according to severity, is suggested.

The photodynamic effect of rose bengal on proteins of the mitochondrial inner membrane

Photodynamic action promoted by Rose Bengal was evaluated in solutions of unsaturated fatty acids or histidine, and on beef heart submitochondrial particles. Rose Bengal-promoted photooxidation of histidine was mainly due to the opening up of the imidazole ring by singlet oxygen. Photosensitization of polyunsaturated fatty acids (PUFA) resulted in oxygen consumption and thiobarbituric acid-reactive substances (TBARS) formation, the extent of which was linearly related to the increasing degree of unsaturation. Photosensitization of submitochondrial particles caused oxygen consumption and TBARS production. These processes involved two different reaction components: during the first, most of the mitochondrial proteins were inactivated, the most sensitive being succinate dehydrogenase and cytochrome c. The values for the rate ratios of [TBARS] formation/[O2] consumption for the first and second phase were 0.36 and 1.32%, respectively, pointing to a larger contribution of lipid peroxidation during the second phase. The calculation of the rate constants for reaction of singlet oxygen with mitochondrial proteins suggests that singlet oxygen is more reactive towards proteins than to PUFA. The biological role of this selectivity is discussed in terms of the mitochondria as one of the first targets for photosensitized reactions.

Photosensitization of single-strand breaks in pBR322 DNA by rose bengal

Rose bengal photosensitized the formation of frank single-strand breaks (SSBs) in double-stranded, supercoiled pBR322 DNA as measured by neutral agarose electrophoresis. The yield of SSBs followed first order kinetics with respect to light fluence and dye concentration. The efficiency of cleavage was more than 20 times greater in an argon atmosphere than in an oxygen atmosphere. The quantum yield in an air atmosphere was 1.7 (+/- 0.3) X 10(-8). Sodium azide quenched the cleavage more efficiently in an oxygen atmosphere than when the oxygen concentration was reduced. Isopropanol and mannitol were poor quenchers; ribose-5-phosphate and guanosine-5'-monophosphate did not quench the cleavage. Substituting D2O for H2O increased the yield of SSBs in both oxygen and oxygen-depleted atmospheres. The results are consistent with initiation of cleavage by reaction of the triplet state of rose bengal (or a radical derived from it) with DNA. In the presence of oxygen, an additional mechanism is introduced.