Incidence of Nerve Palsies During Pavlik Harness Treatment for Developmental Dysplasia of the Hip: A Retrospective Cohort Study

BACKGROUND

The Pavlik harness has been used for approximately a century to treat developmental dysplasia of the hip (DDH). Femoral nerve palsy is a documented complication of Pavlik harness use, with an incidence ranging from 2.5% to 11.2%. Rare reports of brachial plexus palsy have also been documented. The primary purpose of the current study was to evaluate the incidence of various nerve palsies in patients undergoing Pavlik harness treatment for DDH. Secondary aims were to identify patient demographic or hip characteristics associated with nerve palsy.

METHODS

We performed a retrospective review of patients diagnosed with DDH and treated with a Pavlik harness from February 1, 2016, to April 1, 2023, at a single tertiary care orthopaedic hospital. Hip laterality, use of a subsequent rigid abduction orthosis, birth order, breech positioning, weight, and family history were collected. The median (and interquartile range [IQR]) or mean (and standard deviation [SD]) were reported for all continuous variables. Independent 2-sample t tests and Mann-Whitney U tests were conducted to identify associations between the variables collected at the initiation of Pavlik harness treatment and the occurrence of nerve palsy.

RESULTS

Three hundred and fifty-one patients (547 hips) were included. Twenty-two cases of femoral nerve palsy (4% of all treated hips), 1 case of inferior gluteal nerve palsy (0.18%), and 2 cases of brachial plexus palsy (0.37%) were diagnosed. Patients with nerve palsy had more severe DDH as measured by the Graf classification (p < 0.001) and more severe DDH as measured on physical examination via the Barlow and Ortolani maneuvers (p = 0.003).

CONCLUSIONS

Nerve palsies were associated with more severe DDH at the initiation of Pavlik harness use. Upper and lower-extremity neurological status should be scrutinized at initiation and throughout treatment to assess for nerve palsies. The potential for femoral, gluteal, and brachial plexus palsies should be included in the discussion of risks at the beginning of treatment. Families may be reassured that nerve palsies associated with Pavlik harness can be expected to resolve with a short break from treatment.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

My radius is broken - do I need a cast or is a splint enough?

PURPOSE OF REVIEW

The treatment of many distal radius fractures has shifted from casting to splinting or the application of a soft dressing. This review includes a review of the types of pediatric distal radius fractures and the most recent literature on the management of these injuries.

RECENT FINDINGS

Many nondisplaced distal radius fractures may be treated with removable splints or bandages. This mitigates complications with cast immobilization. Additionally, many of these injuries do not require follow-up treatment and thereby reduce healthcare costs.

SUMMARY

This update on distal radius fractures in the pediatric population highlights changes in the treatment paradigm and demonstrates an opportunity to diminish healthcare costs.

How Do Orthopedic Surgeons Stay Up-to-Date With the Literature? A Survey

Background: With the rise of social media and other web-based platforms, there has been a shift in how medical research findings are disseminated. Questions/Purposes: We sought to investigate how often orthopedic surgeons use different knowledge-seeking methods and how confident they were in their ability to stay up-to-date. Methods: We distributed a 23-question survey to 120 orthopedic surgeons employed at a single tertiary-care metropolitan orthopedic hospital. The survey collected the surgeons' use of reference managers, RSS feeds, and preferred methods of staying up-to-date. Respondents were asked to report the number of hours they spent staying up-to-date per week and their success with keeping up with orthopedic specialty literature. Results: A total of 85 physicians responded (median age, 52 years); 83% of respondents who spent 3 or more hours a week in keeping up-to-date with the literature said they felt successful in doing so, while 40% of participants who spent less than 1 hour a week said they felt successful. Fifty-five percent of surgeons under the median age used social media, while only 29% of surgeons over the median age used social media. Conclusions: This survey suggests that spending only 1 to 2 hours per week was enough to make the orthopedic surgeons we surveyed feel confident that they were keeping up with the literature in their specialty. These findings also suggest that it may be more important for surgeons to choose a convenient method of literature review that will enable them to maximize time spent reading, rather than attempting to use any one source.

The tilts, twists, and turns of torticollis

PURPOSE OF REVIEW

The purpose of this review is to outline the most recent understanding of torticollis in the pediatric population.

RECENT FINDINGS

It is important to diagnose the underlying condition of torticollis early in childhood, as some conditions that cause torticollis may result in major developmental delays in early motor milestones. Recent studies have highlighted that many of the rarer causes of torticollis are often misdiagnosed as congenital muscular torticollis, suggesting that physicians should pay close attention to the results of clinical and radiographic examinations when patients present with torticollis.

SUMMARY

Congenital muscular torticollis is the most common cause of torticollis. Other, less common causes of torticollis include vertebral abnormalities, ocular torticollis, gastrointestinal disorders, soft tissue infections of the neck, posterior fossa tumors, and benign paroxysmal torticollis. Although rare, these differential diagnoses should be considered during a clinical work-up for a patient who presents with torticollis.

Are you sure that ankle is just sprained? A review of common ankle conditions, diagnoses and treatment

PURPOSE OF REVIEW

Acute ankle sprains frequently occur in active children and adolescents but may be the initial clinical presentation of other less common disorders affecting the lower extremities. There are many conditions that may cause one or multiple episodes of ankle injury that are misdiagnosed as an acute ankle sprain. This manuscript highlights diagnoses that should be considered when evaluating and managing a child or adolescent who presents initially and/or repeatedly with an acute ankle sprain.

RECENT FINDINGS

In recent years, various studies have continued to note the prevalence of misdiagnosed ankle sprains, especially amongst the paediatric population. If ankle radiographs demonstrate no abnormalities during an initial clinical examination, often the patient is diagnosed with an acute ankle sprain. However, this can be a misdiagnosis, especially when the patient has had recurrent episodes of ankle injury and ancillary studies are not performed.

SUMMARY

There are many diagnoses that can go unnoticed in the initial evaluation of a paediatric or adolescent ankle sprain. It is important for physicians to be aware of these other conditions to ensure proper treatment plans. This manuscript will analyse five conditions that may be misdiagnosed as an ankle sprain, including juvenile idiopathic arthritis, osteochondritis dissecans of the talus, hereditary sensory motor neuropathy (Charcot-Marie Tooth disease), tarsal coalition and transitional ankle fractures.

Clubfoot for the primary care physician: frequently asked questions

PURPOSE OF REVIEW

This review aims to provide primary care physicians with updates on recent literature regarding clubfoot and answer questions asked by parents and caregivers of children with clubfoot. The topics discussed include prenatal counseling, relapse after Ponseti treatment, long-term outcomes following successful treatment of clubfoot, and the effect of diagnosis and treatment on the parent or caregiver.

RECENT FINDINGS

Clubfoot is one of the most commonly searched orthopaedic conditions on the internet by parents. There is a lack of evidence-based guidelines on clubfoot worldwide. Recent systematic reviews have identified emerging evidence of genetic and modifiable risk factors that lead to clubfoot. Patients treated by the Ponseti method show better ankle power and strength compared with those treated with surgery for residual deformity or recurrence.

SUMMARY

The treatment of clubfoot is a long and involved process. Exposure to and familiarity with the Ponseti method will aid primary care physicians and parents in the optimization of children's clubfoot deformity correction using largely nonoperative management.

Reliability of the Modified Clavien-Dindo-Sink Complication Classification System in Pediatric Orthopaedic Surgery

Background

There is no standardized complication classification system that has been evaluated for use in pediatric or general orthopaedic surgery. Instead, subjective terms such as major and minor are commonly used. The Clavien-Dindo-Sink complication classification system has demonstrated high interrater and intrarater reliability for hip-preservation surgery and has increasingly been used within other orthopaedic subspecialties. This classification system is based on the magnitude of treatment required and the potential for each complication to result in long-term morbidity. The purpose of the current study was to modify the Clavien-Dindo-Sink system for application to all orthopaedic procedures (including those involving the spine and the upper and lower extremity) and to determine interrater and intrarater reliability of this modified system in pediatric orthopaedic surgery cases.

Methods

The Clavien-Dindo-Sink complication classification system was modified for use with general orthopaedic procedures. Forty-five pediatric orthopaedic surgical scenarios were presented to 7 local fellowship-trained pediatric orthopaedic surgeons at 1 center to test internal reliability, and 48 scenarios were then presented to 15 pediatric orthopaedic surgeons across the United States and Canada to test external reliability. Surgeons were trained to use the system and graded the scenarios in a random order on 2 occasions. Fleiss and Cohen kappa (κ) statistics were used to determine interrater and intrarater reliabilities, respectively.

Results

The Fleiss κ value for interrater reliability (and standard error) was 0.76 ± 0.01 (p < 0.0001) and 0.74 ± 0.01 (p < 0.0001) for the internal and external groups, respectively. For each grade, interrater reliability was good to excellent for both groups, with an overall range of 0.53 for Grade I to 1 for Grade V. The Cohen κ value for intrarater reliability was excellent for both groups, ranging from 0.83 (95% confidence interval [CI], 0.71 to 0.95) to 0.98 (95% CI, 0.94 to 1.00) for the internal test group and from 0.83 (95% CI, 0.73 to 0.93) to 0.99 (95% CI, 0.97 to 1.00) for the external test group.

Conclusions

The modified Clavien-Dindo-Sink classification system has good interrater and excellent intrarater reliability for the evaluation of complications following pediatric orthopaedic upper extremity, lower extremity, and spine surgery. Adoption of this reproducible, reliable system as a standard of reporting complications in pediatric orthopaedic surgery, and other orthopaedic subspecialties, could be a valuable tool for improving surgical practices and patient outcomes.

Low Vitamin D Levels in Children with Fractures: a Comparative Cohort Study

BACKGROUND

The currently accepted ranges for "normal" serum vitamin D have recently been challenged in adults on the basis that healthy bone metabolism requires higher levels of vitamin D than previously thought.

PURPOSE

The purpose of this study was to evaluate whether a new "biologically based" classification based on 25(OH)vitamin D levels that invoke an endocrine biomarker response (<20 ng/mL for deficiency and <32 ng/mL for insufficiency) is more appropriate for children with fractures than historical criteria.

METHODS

Serum 25(OH)vitamin D levels were collected from 58 children with acute low-energy fractures from an outpatient orthopedic clinic from 2009 to 2012. These vitamin D levels were compared with a cohort of 103 children with chronic kidney disease (CKD) from an adjacent clinic, a condition with acknowledged low levels of vitamin D. Then, the prevalence of vitamin D sufficiency in the fracture cohort was evaluated and compared using both historical guidelines and newer biologically based criteria.

RESULTS

25(OH)vitamin D levels in the fracture cohort did not differ from levels in the CKD cohort (27.5 vs. 24.6 ng/mL) indicating a similar distribution of vitamin D levels. This finding was consistent when controlling for significant covariables using linear regression analyses. In the fracture cohort, there was a discrepancy between historical and biologically based criteria in 64% of children.

CONCLUSIONS

The results of the current study suggest that fracture patients are more frequently vitamin D deficient than previously thought. This finding is more readily apparent when newer biologically based criteria for vitamin D sufficiency are used.

Breeder age influences embryogenesis in broiler hatching eggs

The effects of dietary fat and broiler breeder age on egg and embryo characteristics during incubation were investigated. Breeders were fed diets containing no added fat or 3.0% added poultry fat (PF) for peak energy intakes of 430 and 467 kcal/hen day (pC/d), or 1.5% PF or 3.0% corn oil at 449 pC/d. Feeding of diets was initiated at 22 wk, and eggs were collected for incubation at 27 and 36 wk of age. Percentage incubational egg weight loss was determined between day of set and Days 6, 12, and 18. Percentage wet and dry embryo weights, embryo moisture content, and eggshell weights were determined at 6, 12, and 18 d of incubation. Percentage yolk sac weight and wet and dry liver weights and moisture content were determined on Days 12 and 18. Percentage gall bladder weight was determined on Day 18. There were no observed effects due to breeder diet. However, eggshell weight at Days 6, 12, and 18 was higher in 27-wk-old hens compared with 36-wk-old hens. Conversely, egg weight loss between Day 0 and Days 6, 12, and 18 and yolk sac weight across Days 12 and 18 of incubation were lower in eggs at 27 wk of age compared with 36 wk. At Day 18, dry embryo weight was higher and wet liver weight was lower at 27 wk compared with 36 wk. A slower rate of DM accumulation in embryos at Week 36 compared to Week 27 was associated with increased incubational water loss and decreased embryo moisture content, eggshell percentage, and yolk sac absorption rate. These data demonstrate that changes in eggshell characteristics with broiler breeder age can alone impact yolk uptake, growth, and body composition in subsequent embryos.

SecA folds via a dimeric intermediate

Though many proteins in the cell are large and multimeric, their folding has not been extensively studied. We have chosen SecA as a folding model because it is a large, homodimeric protein (monomer molecular mass of 102 kDa) with multiple folding domains. SecA is the ATPase for the Sec-dependent preprotein translocase of many bacteria. SecA is a soluble protein that can penetrate into the membrane during preprotein translocation. Because SecA may partially unfold prior to its insertion into the membrane, studies of its stability and folding pathway are important for understanding how it functions in vivo. Kinetic folding transitions in the presence of urea were monitored using circular dichroism and tryptophan fluorescence, while equilibrium folding transitions were monitored using the same techniques as well as a fluorescent ATP analogue. The reversible equilibrium folding transition exhibited a plateau, indicating the presence of an intermediate. Based on the data presented here, we propose a three-state model, N(2) if I(2) if 2U, where the native protein unfolds to a dimeric intermediate which then dissociates into two unfolded monomers. The SecA dimer was determined to have an overall stability (DeltaG) of -22.5 kcal/mol. We also investigated the stability of SecA using analytical ultracentrifugation equilibrium and velocity sedimentation, which again indicated that native or refolded SecA was a stable dimer. The rate-limiting step in the folding pathway was conversion of the dimeric intermediate to the native dimer. Unfolding of native, dimeric SecA was slow with a relaxation time in H(2)O of 3.3 x 10(4) s. Since SecA is a stable dimer, dissociation to monomeric subunits during translocation is unlikely.

GroEL binds a late folding intermediate of phage P22 coat protein

GroEL recognizes proteins that are folding improperly or that have aggregation-prone intermediates. Here we have used as substrates for GroEL, wildtype (WT) coat protein of phage P22 and 3 coat proteins that carry single amino acid substitutions leading to a temperature-sensitive folding (tsf) phenotype. In vivo, WT coat protein does not require GroEL for proper folding, whereas GroEL is necessary for the folding of the tsf coat proteins; thus, the single amino acid substitutions cause coat protein to become a substrate for GroEL. The conformation of WT and tsf coat proteins when in a binary complex with GroEL was investigated using tryptophan fluorescence, quenching of fluorescence, and accessibility of the coat proteins to proteolysis. WT coat protein and the tsf coat protein mutants were each found to be in a different conformation when bound to GroEL. As an additional measure of the changes in the bound conformation, the affinity of binding of WT and tsf coat proteins to GroEL was determined using a fluorescence binding assay. The tsf coat proteins were bound more tightly by GroEL than WT coat protein. Therefore, even though the proteins are identical except for a single amino acid substitution, GroEL did not bind these substrate polypeptides in the same conformation within its central cavity. Therefore, GroEL is likely to bind coat protein in a conformation consistent with a late folding intermediate, with substantial secondary and tertiary structure formed.

Effects of breeder age and dietary fat source and level on broiler hatching egg characteristics

The effects of breeder age and added dietary fat source and level on broiler hatching egg characteristics were evaluated. Diets included no added fat (NAF) or 3.0% added poultry fat (PF) for peak energy intakes of 430 and 467 kcal/hen-day (PCD) or 1.5% PF or 3.0% corn oil (CO) at 449 PCD. As added dietary fat was changed from CO to PF, the percentage of unsaturated dietary fatty acids, including linoleic acid, decreased. Feeding of experimental diets was initiated when breeders were 22 wk old. Total fresh egg weight; eggshell weight; percentages of yolk (PYK), albumen (PAB), and eggshell (PSHL) weights; and yolk:albumen ratio were measured at various weeks between 26 and 47 wk of age. Egg weight increased progressively with hen age. Significant increases in yolk:albumen ratio occurred between Weeks 26 and 31 and between Weeks 31 and 35. Low (430 PCD) dietary energy levels significantly reduced PYK at 35 wk and increased PAB across breeder age. Eggshell weight was lower in birds fed moderate (449 PCD) compared to low energy levels at Week 26, moderate compared to high (467 PCD) energy levels at Week 41, and PF compared to CO across fat level at Week 31. At Weeks 31 and 41, PSHL was increased by the use of 3.0% PF compared to 1.5%, and PSHL was increased at Weeks 26 and 41 by using added PF compared to CO across fat level. Increased dietary energy decreased PAB and the use of added dietary CO rather than PF decreased PSHL in broiler breeders between 26 and 47 wk of age.

Effects of dietary fat type and level on broiler breeder performance

The effects of added dietary fat type and level on broiler breeder performance were evaluated in two trials. In Trial 1, diets included no added fat (NAF) or 3.0% added poultry fat (PF) for individual bird energy intakes of 430 and 467 kcal/d at peak production (PCD), or 1.5% PF or 3.0% corn oil (CO) at 449 PCD. In Trial 2, diets contained NAF, 1.5 or 3.0% added CO or PF, or 3.0% lard (LA) for peak energy intakes of 463 PCD. All diets in Trial 2 were isocaloric and isonitrogenous. Feeding of experimental diets was initiated when breeders were 22 wk old in both trials, and hen BW was measured at various weeks between 22 and 47 wk in Trial 1 and between 27 and 65 wk in Trial 2. Egg production, egg weight (EW), eggshell quality, and hatchability were recorded at various weeks between 24 and 48 wk in Trial 1 and between 27 and 64 wk in Trial 2. Body weights and EW increased progressively, and eggshell quality fluctuated variably with age. Egg production peaked between Weeks 32 and 35, and hatchability was significantly depressed at Week 63. Egg weight and hatchability were not affected by dietary treatment; however, BW increased with energy level in the diet between Weeks 27 and 47. Body weight was also higher in birds fed 1.5 or 3.0% added fat compared with NAF and was higher in birds fed LA compared with CO at the 3.0% level. Egg specific gravity and shell weight per unit of surface area at Week 41 were increased by feeding low or high energy compared with moderate energy, and relative eggshell conductance was increased by using moderate compared with high energy diets and by feeding 1.5% PF compared with 3.0% PF. Egg specific gravity was increased by PF when compared with CO across fat level at Weeks 26 and 47 and by LA when compared with PF across fat level and breeder age. These data suggest that certain dietary energy and fat regimens may affect BW and eggshell quality without associated effects on EW and hatchability at various breeder ages.

Resection arthroplasty of the hip for patients with cerebral palsy: an outcome study

Thirteen patients (18 hips) with cerebral palsy and painful hip subluxation or dislocation underwent proximal femoral resection-interposition arthroplasty (PFRIA) as a salvage procedure for intractable pain or seating difficulty. Eleven patients (14 hips) had a prior failed soft-tissue or bony reconstruction. The average age at surgery was 26.6 years (range, 10.7-45.5 years), and average follow-up was 7.4 years (range, 2.2-20.8 years). All patients/caregivers noted significant improvement in subjective assessment of pain after the surgery. Upright sitting tolerance improved from an average preoperative value of 3.2-8.9 h postoperatively (p < 0.01). Four patients who were unable even to sit in a customized wheelchair before the operation could be easily seated in a custom chair after surgery. Hip range of motion including flexion, extension, and abduction was significantly improved postoperatively (p < 0.05). Single-dose radiation therapy was used postoperatively for five hips and resulted in a significantly lower grade of heterotopic ossification at final follow-up (p < 0.005). Skeletal traction in the postoperative period did not prevent proximal migration of the femur compared with skin traction. Maximal pain relief was achieved at an average of 5.6 months postoperatively (range, 0.03-14 months). Complications included transient postoperative decubitus ulceration (four patients), pneumonia (two patients), and symptomatic heterotopic bone (two patients). The significant improvements in pain management, sitting tolerance, and range of motion suggest that PFRIA is a reasonable salvage procedure for the painful, dislocated hip in cerebral palsy. Resolution of pain may not be immediate, as was noted in this series.

Types of persistent dysplasia in congenital dislocation of the hip

This article reports five types of persistent bony dysplasia in patients with congenital dislocation of the hip (CDH), suggests the pathogeneses, and discusses the treatment options. We consider the five types to be (1) maldirected acetabulum, (2) capacious acetabulum, (3) false acetabulum, (4) lateralized acetabulum, and (5) femoral deformity. The maldirected acetabulum persists when the acetabulum continues to face forward and laterally. The capacious acetabulum arises from joint instability; capsular laxity permits the proximal femur to slide within the acetabulum. The false acetabulum results from an ectopic fibrocartilaginous cavity in the pelvis created by the subluxated or dislocated femoral head.44 The lateralized acetabulum occurs with ossification of the cotyloid cavity from longstanding lateral subluxation or dislocation or premature closure of the triradiate cartilage. Femoral deformities include valgus and anteversion of the femoral neck, capital femoral physeal growth arrest, discrepancy between the greater trochanter and the femoral head, and femoral head asphericity. After clinical and radiographic evaluation, we believe that an understanding of the pathogeneses and types of dysplasia will facilitate appropriate treatment programs. Treatments consist of acetabular redirection, acetabular reconstruction, femoral osteotomies, and salvage procedures.

Automated system for capture and detection of nucleic acids

A fully automated nucleic acid analysis system is described, which offers positive sample identification, improved sensitivity and reduced user interaction compared to conventional techniques. The system relies on the sequence-specific capture of DNA onto solid-phase particles, confirming product identity without the problems of interpretation and lack of sequence information inherent in gel-based analyses. The system can be used for sequence confirmation, mutation analysis and semiquantitative detection of PCR products.

Symptomatic talonavicular coalition

Talonavicular coalition is reported as an asymptomatic congenital anomaly of the foot that is noticed incidentally on radiographs of the foot, and is often associated with symphalangism, clinodactyly, ball-and-socket ankle joint, a great toe that is shorter than the second toe, and an autosomal dominant inheritance pattern. We describe here three patients with five involved feet. All three patients had chronic foot pain not secondary to trauma, and all five feet required treatment to alleviate the pain.

Effects of breeder age and dietary fat on subsequent broiler performance. 2. Slaughter yield

The effects of breeder age (35, 51, and 63 wk) and added dietary fat on subsequent broiler slaughter yield were evaluated. Beginning at 22 wk of age, diets included 0, 1.5, or 3.0% added poultry fat (PF), 1.5 or 3.0% added corn oil (CO), or 3.0% added lard (LA). Slaughter yields were greatest in broilers from 63-wk-old breeders. Added CO in broiler breeder diets significantly increased subsequent 43-d live BW and chilled carcass yields compared to LA. Furthermore, CO diets significantly increased relative front-half yields compared to PF diets; and compared to the 3.0% fat level, 1.5% added fat significantly increased 43-d live BW, regardless of fat type. In conclusion, breeder age influenced broiler slaughter yield, and fat added at the 1.5% level to breeder hen diets was an effective energy source. However, less saturated fat improved subsequent slaughter yield.

Effects of breeder age and dietary fat on subsequent broiler performance. 1. Growth, mortality, and feed conversion

The effects of breeder age (35, 51, and 63 wk) and added dietary fat on subsequent broiler growth, mortality, and feed conversion through 42 d were evaluated. Beginning at 22 wk of age, diets included 0, 1.5, or 3.0% added poultry fat (PF), 1.5 or 3.0% added corn oil (CO), or 3.0% added lard (LA). Broilers from hens 35 wk of age performed better between 0 and 21 d than those from 51- and 63-wk-old hens. Conversely, between 22 and 42 d, broilers from hens 51 wk of age performed better than those at 35 and 63 wk. In relation to PF, CO added to breeder diets increased 0 to 21 d BW gain in broilers; whereas, feed conversion between 22 and 42 d was reduced in broilers from hens fed PF compared to those fed CO. In conclusion, breeder age influenced broiler performance differently throughout the growout period. Fat added at the 1.5% level to breeder hen diets was an effective energy source. However, less saturated fat improved growout performance.

Effects of dietary fat and eggshell cuticle removal on egg water loss and embryo growth in broiler hatching eggs

The effects of dietary fat and eggshell cuticle removal on egg water loss, embryo growth, and hatchability were determined in eggs from broiler breeder hens at different ages. Hens were fed isocaloric diets containing one of three different types and levels of added fat. In addition, eggs were either left intact or washed to remove the eggshell cuticle prior to set. Cuticle removal increased egg water loss between 43 and 62 wk. Cuticle removal increased relative wet embryo weight at Week 52 and relative dry embryo weight at 52 and 62 wk. Furthermore, at 62 wk, diet and day of incubation interacted to affect wet embryo weight, and diet variably affected dry embryo weight. No treatment differences were observed for cumulative hatchability, rate of hatch, and relative yolk sac weight at Day 19 of incubation. It was concluded that cuticle removal and the addition of fat to breeder diets may influence embryonic growth without having any subsequent effects on hatchability.

Digital radiography in paediatrics: radiation dose considerations and magnitude of possible dose reduction

The purpose of this study was to evaluate the radiation doses received by paediatric patients examined using a digital radiography unit, and to compare these doses with those received from conventional screen-film systems. In this way, guidelines could be drawn up concerning the magnitude of possible dose reductions achievable using digital radiography. The study was undertaken on approximately 900 patients undergoing abdomen, chest, pelvis and skull examinations. Patients were categorized into the following age groups: 0-1 month, 1-12 months, 1-5 years, 5-10 years and 10-15 years. Approximately half were X-rayed using a Fuji computed radiography system and half using a conventional screen-film system. Entrance surface dose was calculated from the recorded exposure parameters and measured X-ray tube outputs. Dose-area product was recorded directly. Image quality was assessed clinically using criteria recommended by a working group of the Commission of the European Communities. Apart from chest examinations, it was found possible to reduce doses by about 40% on average, by using a computed radiography system instead of a 600 speed screen-film combination. There was no significant difference in the dose for chest examinations. Satisfactory image quality can therefore be achieved by using computed radiography as a 1000 speed system for abdomen, pelvis and skull examinations, and as a 600 speed system for chests. Since very few departments appear to use screen-film systems of speeds greater than 400, then, for most departments, the use of computed radiography would result in dose reductions of at least 60%, or 33% for chests.

Broiler breeder age and dietary fat influence the yolk fatty acid profiles of fresh eggs and newly hatched chicks

The purpose of the present study was to investigate the combined effects of breeder age (36-, 51-, or 64-wk) and different dietary fat sources (3% added corn oil, poultry fat, or lard) on lipids in fresh egg yolks and yolks of newly hatched chicks. Isocaloric breeder diets were altered by the inclusion of different types of dietary fat such that the poultry fat and lard diets had the highest levels of saturated fatty acids when compared to the corn oil diet. Fresh egg yolks obtained from 36-wk-old breeders exhibited higher levels of palmitoleic acid when compared to the levels observed in fresh egg yolks of 51- or 64-wk-old breeders. Furthermore, these levels decreased significantly by 21 d of incubation only in eggs from 36-wk-old hens. At 36 wk of breeder age, the levels of oleic and arachidonic acid were higher in yolks from hatched chicks than in previous fresh egg values, regardless of type of added dietary fat; whereas the level of linoleic acid was higher only in yolks from hatched chicks compared to those of fresh eggs from 36-wk-old hens fed 3% added corn oil. These data suggest that breeder age influences the utilization of yolk lipid by developing embryos, and that the type of fat provided in the diet may have an additional influence.

Binding of beta-amyloid to the p75 neurotrophin receptor induces apoptosis. A possible mechanism for Alzheimer's disease

Alzheimer's disease is a neurodegenerative disorder characterized by the extracellular deposition in the brain of aggregated beta-amyloid peptide, presumed to play a pathogenic role, and by preferential loss of neurons that express the 75-kD neurotrophin receptor (p75NTR). Using rat cortical neurons and NIH-3T3 cell line engineered to stably express p75NTR, we find that the beta-amyloid peptide specifically binds the p75NTR. Furthermore, 3T3 cells expressing p75NTR, but not wild-type control cells lacking the receptor, undergo apoptosis in the presence of aggregated beta-amyloid. Normal neural crest-derived melanocytes that express physiologic levels of p75NTR undergo apoptosis in the presence of aggregated beta-amyloid, but not in the presence of control peptide synthesized in reverse. These data imply that neuronal death in Alzheimer's disease is mediated, at least in part, by the interaction of beta-amyloid with p75NTR, and suggest new targets for therapeutic intervention.

The folded conformation of phage P22 coat protein is affected by amino acid substitutions that lead to a cold-sensitive phenotype

Three cold-sensitive mutants in phage P22 coat protein have been characterized to determine the effects of the amino acid substitutions that cause cold sensitivity on the folding pathway and the conformation of refolded coat protein. Here we find that the three cold-sensitive mutants which have the threonine residue at position 10 changed to isoleucine (T10I), the arginine residue at position 101 changed to cysteine (R101C), or the asparagine residue at position 414 changed to serine (N414S) were capable of folding from a denatured state into a soluble monomeric species, but in each case, the folded conformation was altered. Changes in the kinetics of folding were observed by both tryptophan and bisANS fluorescence. In contrast to the temperature-sensitive for folding coat protein mutants which can be rescued at nonpermissive temperatures in vivo by the overproduction of molecular chaperones GroEL and GroES [Gordon, C. L., Sather, S. K., Casjens, S., & King, J. (1994) J. Biol. Chem. 269, 27941-27951], the folding defects associated with the cold-sensitive amino acid substitutions were not recognized by GroEL and GroES.

Effects of breeder hen age and dietary fat on embryonic and neonatal broiler serum lipids and glucose

In two experiments, the effects of dietary fat and breeder hen age on relative yolk sac weight (RYSW) and total serum cholesterol (CHOL), high (HDLC) and low (LDLC) density lipoprotein cholesterol, triglycerides (TRI), and glucose (GLU) were monitored in broiler embryos and chicks. In Experiment 1, embryos at 18 d of incubation and chicks at hatch were sampled from eggs laid by breeder hens at 26 (young), 36, and 48 wk of age. No dietary effects were noted in either experiment; however, chicks from young hens exhibited elevated serum CHOL, HDLC, LDLC, and lower GLU when compared with chicks from hens at either 36 or 48 wk of age. Additionally, embryos from young breeders displayed a lower RYSW at 18 d of incubation. Conversely, by hatch there was no difference in RYSW among offspring from different aged hens. In Experiment 2, newly hatched chicks were sampled from breeder hens at 36, 51, and 64 wk of age. Dietary effects were also not evident in this experiment; however, chicks from 51-wk-old breeders displayed the highest and lowest serum HDLC and TRI, respectively, compared to the other two age groups, whereas chicks from either 51- or 64-wk-old breeders exhibited higher levels of CHOL than those at 36 wk. Chicks from 64-wk-old breeders displayed an increase in LDLC when compared with the other two ages. These data suggest that serum concentrations of lipids and GLU, and RYSW in 18 d embryos and newly hatched chicks are influenced by hen age and not by added dietary fat.

Nerve growth factor rescues pigment cells from ultraviolet-induced apoptosis by upregulating BCL-2 levels

Apoptosis plays an important role in eliminating dysfunctional damaged cells. For skin, the best characterized injurious environmental agent is ultraviolet (UV) irradiation. Most of the damaging UV irradiation is absorbed in the epidermis and leads to apoptosis of keratinocytes. However, epidermal melanocytes appear to be protected from UV-induced apoptosis. We now report that in pure cultures melanocytic cells undergo characteristic apoptosis after physiologic UV exposures. However, nerve growth factor (NGF) supplementation protects them from this programmed cell death. Furthermore, we show that NGF protects melanocytic cells from UV-induced apoptosis by upregulating BCL-2 protein in these cells and that prior downregulation of BCL-2 abrogates the NGF protective effect on melanocytes. Our data suggest that NGF, known to be constitutively produced by epidermal keratinocytes and induced in these cells after UV irradiation, may preserve the population of cutaneous melanocytes that would otherwise be depleted by casual sun exposure.

Time-averaged indoor Rn concentrations and infiltration rates sampled in four U.S. cities

Indoor Rn concentrations, measured in 58 houses during a 4- to 5-mon period during the winter and spring of 1981-1982, varied from 0.1-16 pCi l-1 (4-590 Bq m-3). Average infiltration rates were determined for each house during the same period, based on a measurement of the effective leakage area and an infiltration model, and found to range from 0.2-2.2 air changes per hour (h-1). Indoor Rn concentrations correlated poorly with infiltration rates for houses within each city as well as for the entire sample. Differences in Rn entry rates among houses thus appear to be more important than differences in infiltration rates in determining whether a house has high indoor Rn levels, consistent with previous indications from grab-sample measurements. Radon entry rates and indoor Rn concentrations were generally higher in houses in Fargo, ND, and Colorado Springs, CO, than in houses in Portland, ME, and Charleston, NC.