Radiographic Evaluation of Bone Adaptation Adjacent to Percutaneous Osseointegrated Prostheses in a Sheep Model

Background

Percutaneous osseointegrated prostheses (POPs) are being investigated as an alternative to conventional socket suspension and require a radiographic followup in translational studies to confirm that design objectives are being met.

Questions/purposes

In this 12-month animal study, we determined (1) radiographic signs of osseointegration and (2) radiographic signs of periprosthetic bone hypertrophy and resorption (adaptation) and (3) confirmed them with the histologic evidence of host bone osseointegration and adaptation around a novel, distally porous-coated titanium POP with a collar.

Methods

A POP device was designed to fit the right metacarpal bone of sheep. Amputation and implantation surgeries (n = 14) were performed, and plane-film radiographs were collected quarterly for 12 months. Radiographs were assessed for osseointegration (fixation) and bone adaptation (resorption and hypertrophy). The cortical wall and medullary canal widths were used to compute the cortical index and expressed as a percentage. Based on the cortical index changes and histologic evaluations, bone adaptation was quantified.

Results

Radiographic data showed signs of osseointegration including those with incomplete seating against the collar attachment. Cortical index data indicated distal cortical wall thinning if the collar was not seated distally. When implants were bound proximally, bone resorbed distally and the diaphyseal cortex hypertrophied.

Conclusions

Histopathologic evidence and cortical index measurements confirmed the radiographic indications of adaptation and osseointegration. Distal bone loading, through collar attachment and porous coating, limited the distal bone resorption.

Clinical Relevance

Serial radiographic studies, in either animal models or preclinical trials for new POP devices, will help to determine which designs are likely to be safe over time and avoid implant failures.     

Temporal lobe discharges and glossolalia

Glossolalia (speaking in tongues) is a religious phenomenon of which there has been only limited scientific investigation. Described here is the case of a 44-year-old woman who had clonic jerking of the left forearm while speaking in tongues. Waking EEG while she was thinking of nothing in particular was normal. After several minutes of silently praying in tongues she manifested right temporal sharp wave discharges and may have been in a state resembling light sleep. Possible relationships between glossolalia, ecstatic religious phenomena, and temporal lobe electrical discharges are discussed.     

Autism spectrum disorder severity reflects the average contribution of de novo and familial influences

Autism spectrum disorders (ASDs) are a highly heterogeneous group of conditions—phenotypically and genetically—although the link between phenotypic variation and differences in genetic architecture is unclear. This study aimed to determine whether differences in cognitive impairment and symptom severity reflect variation in the degree to which ASD cases reflect de novo or familial influences. Using data from more than 2,000 simplex cases of ASD, we examined the relationship between intelligence quotient (IQ), behavior and language assessments, and rate of de novo loss of function (LOF) mutations and family history of broadly defined psychiatric disease (depressive disorders, bipolar disorder, and schizophrenia; history of psychiatric hospitalization). Proband IQ was negatively associated with de novo LOF rate (P = 0.03) and positively associated with family history of psychiatric disease (P = 0.003). Female cases had a higher frequency of sporadic genetic events across the severity distribution (P = 0.01). High rates of LOF mutation and low frequencies of family history of psychiatric illness were seen in individuals who were unable to complete a traditional IQ test, a group with the greatest degree of language and behavioral impairment. These analyses provide strong evidence that familial risk for neuropsychiatric disease becomes more relevant to ASD etiology as cases become higher functioning. The findings of this study reinforce that there are many routes to the diagnostic category of autism and could lead to genetic studies with more specific insights into individual cases.The set of conditions diagnosed as autism spectrum disorders (ASDs) vary enormously in their presentation (1). The most severely impaired individuals—often those with intellectual disabilities, limited speech, and severe behavioral problems—can require lifelong care. At the other end of the functional spectrum, people diagnosed with ASDs can be verbally fluent and academically gifted and can achieve independence in adulthood (2, 3). The broad range of cognitive and behavioral profiles seen in diagnosed ASDs has been long viewed as a challenge by the research community (4). Although it is well established that (i) the cognitive/behavioral profile of people diagnosed with ASDs varies widely and (ii) the set of genetic factors related to ASDs varies widely (5, 6), the degree to which phenotype can be used to predict patterns in disease architecture remains unclear.Recent insights into the genetic influences on ASDs offer an opportunity to investigate this question through the lens of de novo vs. familial effects. On average, ASDs run in families. The siblings of children with ASDs are 10–20 times more likely to receive a diagnosis of ASD themselves (7, 8); the parents of children with ASDs are more likely to manifest autistic features, as well as a variety of other neuropsychiatric conditions, such as schizophrenia and bipolar disorder (9, 10). These epidemiologic observations are consistent with analyses suggesting that ASDs are influenced by thousands of common genetic variants transmitted between generations. It has been estimated that common, genotyped SNPs account for 20–60% of variation in ASD risk, although the effect of any individual SNP is likely very small (11–13). Many of these influences are shared with other psychiatric disorders (12, 14), which at least in part explains the familial clustering of different types of behavior problems.However, statistics about ASD heritability reflect an average. For example, there are likely many affected families for whom sibling recurrence risk is less than 10–20%. The strongest evidence toward this claim comes from studies of rare, severely deleterious genetic events that are associated with ASDs (15–20). Events of this type, for example copy number variants and loss of function (LOF) mutations, are often de novo (not seen in an affected individual’s parents). Although cases of ASDs involving a de novo mutation could reflect a concert of spontaneous and inherited genetic events, de novo events of large effect may reduce the likelihood of seeing psychiatric problems in an affected individual’s family members.     

Podiatrist care and outcomes for patients with diabetes and foot ulcer

We examined whether outcomes of care (amputation and hospitalisation) among patients with diabetes and foot ulcer differ between those who received pre‐ulcer care from podiatrists and those who did not. Adult patients with diabetes and a diagnosis of a diabetic foot ulcer were found in the MarketScan Databases, 2005–2008. Multivariate Cox proportional hazard models estimated the hazard of amputation and hospitalisation. Logistic regression estimated the likelihood of these events. Propensity score weighting and regression adjustment were used to adjust for potentially different characteristics of patients who did and did not receive podiatric care. The sample included 27 545 patients aged greater than 65+ years (Medicare‐eligible patients with employer‐sponsored supplemental insurance) and 20 208 patients aged lesser than 65 years (non Medicare‐eligible commercially insured patients). Care by podiatrists in the year prior to a diabetic foot ulcer was associated with a lower hazard of lower extremity amputation, major amputation and hospitalisations in both non Medicare‐eligible commercially insured and Medicare‐eligible patient populations. Systematic differences between patients with diabetes and foot ulcer, receiving and not receiving care from podiatrists were also observed; specifically, patients with diabetes receiving care from podiatrists tend to be older and sicker.     

The effects of aerobic exercise on glucose and counterregulatory hormone concentrations in children with type 1 diabetes

OBJECTIVE: To examine the acute glucose-lowering effects of aerobic exercise in children and adolescents with type 1 diabetes. RESEARCH DESIGN AND METHODS: Fifty children and adolescents with type 1 diabetes (ages 10 to <18 years) were studied during exercise. The 75-min exercise session consisted of four 15-min periods of walking on a treadmill to a target heart rate of 140 bpm and three 5-min rest periods. Blood glucose and plasma glucagon, cortisol, growth hormone, and norepinephrine concentrations were measured before, during, and after exercise. RESULTS: In most subjects (83%), plasma glucose concentration dropped at least 25% from baseline, and 15 (30%) subjects became hypoglycemic (< or = 60 mg/dl) or were treated for low glucose either during or immediately following the exercise session. The incidence of hypoglycemia and/or treatment for low glucose varied significantly by baseline glucose, occurring in 86 vs. 13 vs. 6% of subjects with baseline values <120, 120-180, and >180 mg/dl, respectively (P < 0.001). Exercise-induced increases in growth hormone and norepinephrine concentrations were marginally higher in subjects whose glucose dropped < or = 70 mg/dl. Treatment of hypoglycemia with 15 g of oral glucose resulted in only about a 20-mg/dl rise in glucose concentrations. CONCLUSIONS: In youth with type 1 diabetes, prolonged moderate aerobic exercise results in a consistent reduction in plasma glucose and the frequent occurrence of hypoglycemia when preexercise glucose concentrations are <120 mg/dl. Moreover, treatment with 15 g of oral glucose is often insufficient to reliably treat hypoglycemia during exercise in these youngsters.