Clinical recovery from concussion-return to school and sport: a systematic review and meta-analysis

OBJECTIVE

To define the time frames, measures used and modifying factors influencing recovery, return to school/learn (RTL) and return to sport (RTS) after sport-related concussion (SRC).

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

8 databases searched through 22 March 2022.

ELIGIBILITY CRITERIA

Studies with diagnosed/suspected SRC and interventions facilitating RTL/RTS or investigating the time and modifying factors for clinical recovery. Outcomes included days until symptom free, days until RTL and days until RTS. We documented study design, population, methodology and results. Risk of bias was evaluated using a modified Scottish Intercollegiate Guidelines Network tool.

RESULTS

278 studies were included (80.6% cohort studies and 92.8% from North America). 7.9% were considered high-quality studies, while 23.0% were considered high risk of bias and inadmissible. The mean days until symptom free was 14.0 days (95% CI: 12.7, 15.4; I²=98.0%). The mean days until RTL was 8.3 (95% CI: 5.6, 11.1; I²=99.3%), with 93% of athletes having a full RTL by 10 days without new academic support. The mean days until RTS was 19.8 days (95% CI: 18.8, 20.7; I²=99.3%), with high heterogeneity between studies. Several measures define and track recovery, with initial symptom burden remaining the strongest predictor of longer days until RTS. Continuing to play and delayed access to healthcare providers were associated with longer recovery. Premorbid and postmorbid factors (eg, depression/anxiety, migraine history) may modify recovery time frames. Though point estimates suggest that female sex or younger age cohorts take longer to recover, the heterogeneity of study designs, outcomes and overlap in CIs with male sex or older age cohorts suggests that all have similar recovery patterns.

CONCLUSION

Most athletes have full RTL by 10 days but take twice as long for an RTS.

PROSPERO REGISTRATION NUMBER

CRD42020159928.

Targeted interventions and their effect on recovery in children, adolescents and adults who have sustained a sport-related concussion: a systematic review

OBJECTIVES

We evaluated interventions to facilitate recovery in children, adolescents and adults with a sport-related concussion (SRC).

DESIGN

Systematic review including risk of bias (modified Scottish Intercollegiate Guidelines Network tool).

DATA SOURCES

MEDLINE(R) and Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Embase, APA PsycINFO, Cochrane Central Register of Controlled Trials, CINAHL Plus with Full Text, SPORTDiscus and Scopus searched until March 2022.

STUDY ELIGIBILITY CRITERIA

(1) Original research including randomised controlled trials (RCTs), quasi-experimental designs, cohort, comparative effectiveness studies; (2) focus on SRC; (3) English; (4) peer-reviewed and (5) evaluated treatment.

RESULTS

6533 studies were screened, 154 full texts reviewed and 13 met inclusion (10 RCTs, 1 quasi-experimental and 2 cohort studies; 1 high-quality study, 7 acceptable and 5 at high risk of bias). Interventions, comparisons, timing and outcomes varied, precluding meta-analysis. For adolescents and adults with dizziness, neck pain and/or headaches >10 days following concussion, individualised cervicovestibular rehabilitation may decrease time to return to sport compared with rest followed by gradual exertion (HR 3.91 (95% CI 1.34 to 11.34)) and when compared with a subtherapeutic intervention (HR 2.91 (95% CI 1.01 to 8.43)). For adolescents with vestibular symptoms/impairments, vestibular rehabilitation may decrease time to medical clearance (vestibular rehab group 50.2 days (95% CI 39.9 to 60.4) compared with control 58.4 (95% CI 41.7 to 75.3) days). For adolescents with persisting symptoms >30 days, active rehabilitation and collaborative care may decrease symptoms.

CONCLUSIONS

Cervicovestibular rehabilitation is recommended for adolescents and adults with dizziness, neck pain and/or headaches for >10 days. Vestibular rehabilitation (for adolescents with dizziness/vestibular impairments >5 days) and active rehabilitation and/or collaborative care (for adolescents with persisting symptoms >30 days) may be of benefit.

Socioeconomic status and parent perceptions about the costs and benefits of youth sport

Objectives

Describe what costs and benefits parents across the socioeconomic spectrum weight most heavily when making decisions about sport participation for their children.

Method

Cross-sectional survey of a nationally representative online panel of parents of children between the ages of 5 and 18 (n = 1025, 52% response rate). Parents rated the importance of a series of potential costs and benefits of youth sport and these responses were compared across tertiles of per capita family income. We first examined the association between family income tertiles and cost and benefit variables. Model-based cluster analysis was then used to identity homogeneous groups of responses to costs and benefits.

Results

In all income tertiles, the top two benefits of sport were the same: having fun and being physically active. Sport as a means of keeping children out of trouble was very important for 64% of low-income parents as compared to 40% of high-income parents. Obtaining a college athletic scholarship was very important for 26% of low-income parents, as compared to 8% of high-income parents. Relative rankings of potential costs were similar by income tertile, with risk of concussion and other injury and the impact of sport on schoolwork prioritized across tertiles.

Conclusions

Parents prioritized fun and fitness in sport, and were concerned about injury and the impact of sport on academics. Lower income parents were the most likely to view keeping their child out of trouble, and the potential for a college athletics scholarship, as benefits of sport. Efforts to support parental decision making should be grounded in an understanding that family preferences are contextually constrained. While all parents should be appropriately informed about the potential costs and benefits they are weighting in their sports-related decision making, such family-focused efforts should be balanced with the recognition that structural change is needed to address income-related concerns about sport participation.

Selected issues in sport-related concussion (SRC|mild traumatic brain injury) for the team physician: a consensus statement

Selected Issues in Sport-Related Concussion (SRC|Mild Traumatic Brain Injury) for the Team Physician: A Consensus Statement is title 22 in a series of annual consensus documents written for the practicing team physician. This document provides an overview of selected medical issues important to team physicians who are responsible for athletes with sports-related concussion (SRC). This statement was developed by the Team Physician Consensus Conference (TPCC), an annual project-based alliance of six major professional associations. The goal of this TPCC statement is to assist the team physician in providing optimal medical care for the athlete with SRC.

Selected Issues in Sport-Related Concussion (SRC | Mild Traumatic Brain Injury) for the Team Physician: A Consensus Statement

ABSTRACT

Selected Issues in Sport-Related Concussion (SRC | Mild Traumatic Brain Injury) for the Team Physician: A Consensus Statement is title 22 in a series of annual consensus articles written for the practicing team physician. This document provides an overview of select medical issues important to team physicians who are responsible for athletes with sports-related concussion (SRC). This statement was developed by the Team Physician Consensus Conference (TPCC), an annual project-based alliance of six major professional associations. The goal of this TPCC statement is to assist the team physician in providing optimal medical care for the athlete with SRC.

Consensus Statement on Sports-Related Concussions in Youth Sports Using a Modified Delphi Approach

IMPORTANCE

Given the importance of sports-related concussions among youth athletes, the rapid progress of research on this topic over the last decade, and the need to provide further guidance to youth athletes, their families, medical professionals, and athletic personnel and organizations, a panel of experts undertook a modified Delphi consensus process to summarize the current literature and provide recommendations regarding the prevention, assessment, and management of sports-related concussions for young athletes.

METHODS

A consensus panel of 11 experts was created to represent a broad spectrum of expertise in youth sports and concussions. The specific questions to be addressed were developed through an iterative process consisting of 3 rounds, and a review of the literature was conducted to identify research studies related to each question. The consensus panel used a modified Delphi process to reach consensus on the conclusions and recommendations for each question.

RESULTS AND CONCLUSIONS

In 3 Delphi consensus rounds, 7 questions were addressed by the consensus panel of 11 experts, and 26 recommendations for the prevention, assessment, and management of sports-related concussions among young athletes were developed. For many of the questions addressed in this consensus statement, limitations existed in the quantity and quality of the evidence available to develop specific recommendations for youth sports stakeholders.

American Medical Society for Sports Medicine position statement on concussion in sport

Sport-related concussion (SRC) is a common injury in recreational and organised sport. Over the past 30 years, there has been significant progress in our scientific understanding of SRC, which in turn has driven the development of clinical guidelines for diagnosis, assessment and management of SRC. In addition to a growing need for knowledgeable healthcare professionals to provide evidence-based care for athletes with SRC, media attention and legislation have created awareness and, in some cases, fear about many issues and unknowns surrounding SRC. The American Medical Society for Sports Medicine (AMSSM) formed a writing group to review the existing literature on SRC, update its previous position statement, and to address current evidence and knowledge gaps regarding SRC. The absence of definitive outcomes-based data is challenging and requires relying on the best available evidence integrated with clinical experience and patient values. This statement reviews the definition, pathophysiology and epidemiology of SRC, the diagnosis and management of both acute and persistent concussion symptoms, the short-term and long-term risks of SRC and repetitive head impact exposure, SRC prevention strategies, and potential future directions for SRC research. The AMSSM is committed to best clinical practices, evidence-based research and educational initiatives that positively impact the health and safety of athletes.

What are the critical elements of sideline screening that can be used to establish the diagnosis of concussion? A systematic review

BACKGROUND

Sideline detection is the first and most significant step in recognising a potential concussion and removing an athlete from harm. This systematic review aims to evaluate the critical elements aiding sideline recognition of potential concussions including screening tools, technologies and integrated assessment protocols.

DATA SOURCES

Bibliographic databases, grey literature repositories and relevant websites were searched from 1 January 2000 to 30 September 2016. A total of 3562 articles were identified.

STUDY SELECTION

Original research studies evaluating a sideline tool, technology or protocol for sports-related concussion were eligible, of which 27 studies were included.

DATA EXTRACTION

A standardised form was used to record information. The QUADAS-2 and Newcastle-Ottawa tools were used to rate risk of bias. Strength of evidence was assessed using the Grades of Recommendation, Assessment, Development and Evaluation Working Group system.

DATA SYNTHESIS

Studies assessing symptoms, the King-Devick test and multimodal assessments reported high sensitivity and specificity. Evaluations of balance and cognitive tests described lower sensitivity but higher specificity. However, these studies were at high risk of bias and the overall strength of evidence examining sideline screening tools was very low. A strong body of evidence demonstrated that head impact sensors did not provide useful sideline concussion information. Low-strength evidence suggested a multimodal, multitime-based concussion evaluation process incorporating video review was important in the recognition of significant head impact events and delayed onset concussion.

CONCLUSION

In the absence of definitive evidence confirming the diagnostic accuracy of sideline screening tests, consensus-derived multimodal assessment tools, such as the Sports Concussion Assessment Tool, are recommended. Sideline video review may improve recognition and removal from play of athletes who have sustained significant head impact events. Current evidence does not support the use of impact sensor systems for real-time concussion identification.

The effects of tooth extraction on alveolar bone biomechanics in the miniature pig, Sus scrofa

OBJECTIVE

This study investigated the role of occlusion in the development of biomechanical properties of alveolar bone in the miniature pig, Sus scrofa. The hypothesis tested was that the tissues supporting an occluding tooth would show greater stiffness and less strain than that of a non-occluding tooth.

DESIGN

Maxillary teeth opposing the erupting lower first molar (M(1)) were extracted on one side. Occlusion developed on the contralateral side. Serially administered fluorochrome labels tracked bone mineralisation apposition rate (MAR). A terminal experiment measured in vivo buccal alveolar bone strain on occluding and non-occluding sides during mastication. Ex vivo alveolar strains during occlusal loading were subsequently measured using a materials testing machine (MTS/Sintech). Whole specimen stiffness and principal strains were calculated.

RESULTS

MAR tended to be higher on the extraction side during occlusion. In vivo buccal shear strains were higher in the alveolar bone of the occluding side vs. the extraction side (mean of 471 microvarepsilon vs. 281 microvarepsilon, respectively; p=0.04); however, ex vivo shear strains showed no significant differences between sides. Stiffness differed between extraction and occlusion side specimens, significantly so in the low load range (344 vs. 668 MPa, respectively; p=0.04).

CONCLUSIONS

Greater in vivo shear strains may indicate more forceful chews on the occluding side, whereas the similarity in ex vivo bone strain magnitude suggests a similarity in alveolar bone structure and occlusal load transmission regardless of occlusal status. The big overall change in specimen stiffness that was observed was likely attributable to differences in the periodontal ligament rather than alveolar bone.

Behaviour and emotional problems in toddlers with pervasive developmental disorders and developmental delay: associations with parental mental health and family functioning

BACKGROUND

Behavioural and emotional problems occur at a high rate in children and adolescents with intellectual disability, often from a young age. Some studies have indicated that children and adolescents with autism present with even higher rates. Less is known about the presentation, development and family impact of these difficulties in young children with autism. This study aimed to explore these issues in toddlers with pervasive developmental disorders (PDDs), those with delay without a PDD, and their families.

METHODS

Participants were 123 children aged 20-51 months, referred to a developmental assessment clinic. Parents completed a checklist on child behavioural and emotional problems, and individual questionnaires on family functioning, their own mental health, and stress in relation to parenting their child. The child's language and cognitive skills, adaptive functioning and behaviour were assessed by standardized measures. Measures were repeated 1 year postdiagnosis. Behavioural and emotional problems in young children with a PDD were compared with those in children with developmental delay without a PDD, and their impact on parental outcomes explored over time.

RESULTS

Initial and follow-up measures of child behaviour and emotional problems, parent mental health problems, parent stress and family functioning were significantly correlated, providing some evidence of stability over time. Child emotional and behavioural problems contributed significantly more to mother stress, parent mental health problems, and perceived family dysfunction than child diagnosis (PDD/non-PDD), delay or gender. Compared with mothers, all fathers reported significantly less stress in relation to parenting their child.

CONCLUSION

Results highlighted the importance of addressing emotional and behavioural problems in very young children with autism and/or developmental delay. The need for early support and intervention for mothers, fathers and families in this context was also evidenced. As research has shown that behavioural and emotional problems persist into adolescence and young adulthood, understanding of these issues in very young children and their parents has important implications for intervention and long-term outcomes.

Shape of the particulate beam attenuation spectrum and its inversion to obtain the shape of the particulate size distribution

The link between the spectral shape of the beam attenuation spectrum and the shape of the particle size distribution (PSD) of oceanic particles is revisited to evaluate the extent to which one can be predicted from the other. Assuming a hyperbolic (power-law) PSD, N(D) ? D(-xi), past studies have found for an infinite distribution of nonabsorbing spheres with a constant index of refraction that the attenuation spectrum is hyperbolic and that the attenuation spectral slope gamma is related to the PSD slope xi by xi = gamma + 3. Here we add a correction to this model because of the finite size of the biggest particle in the population. This inversion model is given by xi = gamma + 3 - 0.5 exp(-6gamma). In most oceanic observations xi > 3, and the deviation between these two models is negligible. To test the robustness of this inversion, we perturbed its assumptions by allowing for populations of particles that are nonspherical, or absorbing, or with an index of refraction that changes with wavelength. We found the model to provide a good fit for the range of parameters most often encountered in the ocean. In addition, we found that the particulate attenuation spectrum, c(p)(lambda), is well described by a hyperbolic relation to the wavelength c(p) ? lambda(-gamma) throughout the range of the investigated parameters, even when the inversion model does not apply. This implies that knowledge of the particulate attenuation at two visible wavelengths could provide, to a high degree of accuracy, the particulate attenuation at other wavelengths in the visible spectrum.

Aggregation kinetics of extended porphyrin and cyanine dye assemblies

The kinetics of J-aggregate formation has been studied for two chromophores, tetrakis-4-sulfonatophenylporphine in an acid medium and pseudoisocyanine on a polyvinylsulfonate template. The assembly processes differ both in their sensitivity to initiation protocols and in the reaction profiles they produce. The porphyrin's assembly kinetics, for example, displays an induction period unlike that of the cyanine dye. Two kinetic models are presented. For the porphyrin, an autocatalytic pathway in which the formation of an aggregation nucleus is rate-determining appears to be applicable; for the pseudoisocyanine dye, an equation derived for diffusion-limited aggregation of a fractal object satisfactorily fits the data. These models are shown to be useful for the analysis of kinetic data obtained for several biologically important aggregation processes.

How incubation temperature influences the physiology and growth of embryonic lizards

Eggs of two small Australian lizards, Lampropholis guichenoti and Bassiana duperreyi, were incubated to hatching at 25 degrees C and 30 degrees C. Incubation periods were significantly longer at 25 degrees C in both species, and temperature had a greater effect on the incubation period of B. duperreyi (41.0 days at 25 degrees C; 23.1 days at 30 degrees C) than L. guichenoti (40.1 days at 25 degrees C; 27.7 days at 30 degrees C). Patterns of oxygen consumption were similar in both species at both temperatures, being sigmoidal in shape with a fall in the rate of oxygen consumption just prior to hatching. The higher incubation temperature resulted in higher peak and higher prehatch rates of oxygen consumption in both species. Total amount of oxygen consumed during incubation was independent of temperature in B. duperreyi, in which approximately 50 ml oxygen was consumed at both temperatures, but eggs of L. guichenoti incubated at 30 degrees C consumed significantly more (32.6 ml) than eggs incubated at 25 degrees C (28.5 ml). Hatchling mass was unaffected by either incubation temperature or the amount of water absorbed by eggs during incubation in both species. The energetic production cost of hatchling B. duperreyi (3.52 kJ x g(-1)) was independent of incubation temperature, whereas in L. guichenoti the production cost was greater at 30 degrees C (4.00 kJ x g(-1)) than at 25 degrees C (3.47 kJ g(-1)). Snout-vent lengths and mass of hatchlings were unaffected by incubation temperature in both species, but hatchling B. duperreyi incubated at 30 degrees C had longer tails (29.3 mm) than those from eggs incubated at 25 degrees C (26.2 mm). These results indicate that incubation temperature can affect the quality of hatchling lizards in terms of embryonic energy consumption and hatchling morphology.

Vaccination against hepatitis B in patients with chronic liver disease awaiting liver transplantation

BACKGROUND

Most transplant centers in the United States immunize patients awaiting liver transplantation against hepatitis B to prevent acquisition of hepatitis B through transplantation (de novo hepatitis B). A recent study showed that only 16% of patients with cirrhosis awaiting liver transplantation responded to single-dose recombinant vaccine.

METHODS

We studied the immunogenicity of double-dose recombinant vaccine in patients with cirrhosis awaiting liver transplantation.

RESULTS

Over a 4-year period (January 1994 to December 1997), 140 patients with cirrhosis without past or current hepatitis B infection were given double-dose recombinant vaccine (40 microg of Engerix B; SmithKline Beecham, Philadelphia, PA) at 0, 1 to 2, and 2 to 4 months. Hepatitis B surface antibody (HBsAb) was measured 1 to 3 months after completing vaccination. The response rate was 37%. However, HBsAb titers became undetectable in 35% of the responders during the post-transplant follow-up period. One hundred and thirty-seven patients underwent 144 liver transplantation procedures during the study period, and 3 patients developed de novo hepatitis B (2.2%). Livers transplanted from hepatitis B core antibody (HBcAb)-positive donors was the source of de novo hepatitis B in all cases. Two of the 3 patients who developed de novo hepatitis B were immunized before transplantation and one of them was a responder.

CONCLUSION

Although the response rate to double-dose recombinant vaccines is higher than the previously reported response to single-dose vaccine, it still is less than optimal.

Reaction strains on the condylar neck during mastication and maximum muscle stimulation in different condylar positions: an experimental study in the miniature pig

Most researchers agree that the primate temporomandibular joint (TMJ) is loaded compressively during function and that condylar position must play a role in mediating such loads. However, the precise nature of that role remains unclear. Using a pig model in this study, we attempted to analyze strain on the neck of the condyle during normal mastication and during simulated function in different condylar positions. Miniature three-element rosette strain gauges were bonded to the lateral surface of the condylar neck in 4 female miniature pigs (one per condyle). Measurements of strain were made during normal mastication and with the pigs under general anesthesia during maximum stimulation of the masseter and temporalis muscles in each of five condylar positions--centric occlusion, centric relation, anterior, relaxed and wide open--established through use of acrylic splints. Condylar position was evaluated by superimposition of lateral and dorsoventral cephalograms, with measurement of horizontal and vertical changes in location of implants placed on the zygomatic arch. As in primates, the TMJ was found to be load-bearing during mastication, with compressive strain oriented approximately perpendicular to the occlusal plane. In 3 pigs, strain was higher during balancing than during working function. During stimulation, the TMJ reaction strains were significantly lower with the condyles in the anterior position compared with the other positions, and the compressive strain was directed more anteriorly along the neck of the condyle in that position.

Reference standards for quantification of skeletal alkaline phosphatase activity in serum by heat inactivation and lectin precipitation

Putative standards of skeletal alkaline phosphatase (ALP) (from bone, bone cells, osteosarcoma cells, and Pagetic serum) and hepatic ALP (from cholestatic serum and bile) were used to compare three methods for quantifying skeletal ALP activity in serum: heat inactivation, precipitation with wheat germ agglutinin (WGA), and precipitation with concanavalin A (Con A). All the skeletal ALP standards were similarly sensitive to heat inactivation, as were the hepatic ALP standards. Heat inactivation separated skeletal from hepatic ALP by a 50% difference in remaining ALP activities (e.g., 23% and 74% remaining skeletal and hepatic ALP activities after 30 min at 52 degrees C). Differential precipitations with WGA and with Con A were less efficient at separating skeletal from hepatic ALP (maximum differences of < 30% remaining ALP activity). Although both types of hepatic ALP standard (cholestatic serum and bile) were precipitated with similar efficiencies by WGA and Con A, the skeletal ALP standards were not (e.g., at 2.7 g/L, WGA precipitated 78-86% of the ALP activity in Pagetic serum, but only 49% of the ALP activity in extracts of human bone). These data suggest that heat inactivation is preferable to precipitation with WGA or Con A for quantifying skeletal ALP activity in serum: it better separates skeletal from hepatic ALP activity and is not sensitive to glycosyl heterogeneity.

Reference standards for quantification of skeletal alkaline phosphatase activity in serum by heat inactivation and lectin precipitation

Putative standards of skeletal alkaline phosphatase (ALP) (from bone, bone cells, osteosarcoma cells, and Pagetic serum) and hepatic ALP (from cholestatic serum and bile) were used to compare three methods for quantifying skeletal ALP activity in serum: heat inactivation, precipitation with wheat germ agglutinin (WGA), and precipitation with concanavalin A (Con A). All the skeletal ALP standards were similarly sensitive to heat inactivation, as were the hepatic ALP standards. Heat inactivation separated skeletal from hepatic ALP by a 50% difference in remaining ALP activities (e.g., 23% and 74% remaining skeletal and hepatic ALP activities after 30 min at 52 degrees C). Differential precipitations with WGA and with Con A were less efficient at separating skeletal from hepatic ALP (maximum differences of &lt; 30% remaining ALP activity). Although both types of hepatic ALP standard (cholestatic serum and bile) were precipitated with similar efficiencies by WGA and Con A, the skeletal ALP standards were not (e.g., at 2.7 g/L, WGA precipitated 78-86% of the ALP activity in Pagetic serum, but only 49% of the ALP activity in extracts of human bone). These data suggest that heat inactivation is preferable to precipitation with WGA or Con A for quantifying skeletal ALP activity in serum: it better separates skeletal from hepatic ALP activity and is not sensitive to glycosyl heterogeneity.

Fluoride increases net 45Ca uptake by SaOS-2 cells: The effect is phosphate dependent

Previous in vitro studies have shown that the effect of fluoride to increase avian osteoblast-like cell proliferation was dependent on the phosphate concentration. In vitro studies have further revealed that fluoride could also have direct effects on osteoblast-like cells to increase phosphate uptake and transiently increase cytosolic calcium. The current studies were intended to determine whether fluoride could increase net 45Ca uptake by human osteosarcoma (SaOS-2) cells and, if so, whether those effects would also be phosphate dependent. The results of these studies indicate that fluoride increased net 45Ca uptake by SaOS-2 cells, with biphasic dose and time dependencies. After 30 minutes of exposure, net 45Ca uptake was increased to a greater extent by 50 microM fluoride (217 +/- 16% of control, P < 0.001) than by 200 microM fluoride; and the stimulatory effect of 100 microM fluoride on net 45Ca uptake was greater after 20 minutes (187 +/- 22% of control, P < 0.001) than after 60 minutes (122 +/- 7% of control, P < 0.05). These effects of fluoride to increase net 45Ca uptake were dependent on the phosphate concentration in the medium. Fluoride had no effect on net 45Ca uptake in medium containing 0.4 mM phosphate, but increased net 45Ca uptake in medium containing 1.2 or 2.0 mM phosphate (P < 0.005). As the phosphate concentration was increased, the biphasic fluoride dose-response curve was shifted to a lower range of fluoride concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcitonin acutely increases net 45Ca uptake and alters alkaline phosphatase specific activity in human osteosarcoma cells

Although the primary skeletal action of exogenous calcitonin is to inhibit bone resorption, calcitonin also has effects on bone formation. In-vitro data indicate that the latter may include direct effects on bone cells of osteoblastic lineage. In the current studies, we examined the effects of calcitonin on cyclic adenosine monophosphate (cAMP) and PGE2 synthesis and 45Ca uptake in human osteosarcoma cells, specifically, TE-85 cells and subpopulations of SaOS-2 cells with low-, intermediate-, and high-steady-state levels of skeletal alkaline phosphatase (ALP) activity. Since previous in-vivo studies had shown that calcitonin could acutely decrease skeletal ALP activity in rat periosteal osteoblasts, we also measured the effects of calcitonin treatment on ALP specific activity. Neither salmon nor human calcitonin altered the net synthesis of cAMP or PGE2 by SaOS-2 cells, but human calcitonin gene-related peptide increased both (P < .001 and P < .005, respectively). Both salmon and human calcitonin had short-term effects to alter ALP activity in TE-85 and SaOS-2 cells. The effects were different in SaOS-2 subpopulations with different pretreatment ALP levels. Four hours of exposure to salmon calcitonin had dose-dependent, biphasic effects on ALP levels in SaOS-2 cells with intermediate pretreatment ALP levels, increasing ALP at doses between 0.16 and 1.6 nmol/L (P < .005) and decreasing ALP at higher concentrations (P < .05). Both salmon and human calcitonin, but not human calcitonin gene-related peptide, also had short-term effects to increase net 45Ca uptake by SaOS-2 cells; these effects were dose-dependent and long-lasting.(ABSTRACT TRUNCATED AT 250 WORDS)

Significance of the biopsy site of the latissimus dorsi muscle for fiber typing

The use of the latissimus dorsi muscle for cardiomyoplasty requires accurate assessment of the outcome of methods used to convert fast fibers to slow fibers. A knowledge of the normal distribution pattern of slow fibers within the latissimus dorsi is necessary for this endeavor. Fresh latissimus dorsi and teres major muscle tissues from seven pigs, one rabbit, two sheep, one monkey, and four dogs were studied with myosin adenosine triphosphatase staining. Fiber counts were made visually. With the exception of the rabbit, the distribution patterns were similar for all species: (1) intersegmentally--the number of slow fibers decreased steadily from the teres major to the anterior edge of the lateral segment; (2) intrasegmentally--slow fibers were more frequent in the deep layer than the superficial layer; and (3) intrasegmentally--the slow fibers tended to cluster in rosette formations around the neurovascular bundles. These patterns of distribution indicate the need for careful location of biopsies to ensure valid comparison of the amount of slow fibers in tissue before and after treatment.

Quantitation of skeletal alkaline phosphatase isoenzyme activity in canine serum

Pursuing the hypothesis that quantitation of skeletal alkaline phosphatase (ALP) activity in canine serum would provide an index of the rate of bone formation, we compared three methods for isoenzyme-specific identification of skeletal ALP activity in canine serum: heat inactivation, wheat germ agglutinin (WGA) precipitation, and concanavalin A (ConA) precipitation. ALP isoenzyme activities were extracted from canine bone, intestine, and liver, diluted into heat-inactivated canine serum (i.e., serum without ALP activity), and used as calibrators of ALP isoenzyme activities. Differential sensitivity to inhibition by 10 mM L-homoarginine was used to distinguish intestinal ALP activity from hepatic and skeletal ALP activities (i.e., 9, 80, and 72% inhibition, respectively). To allow resolution of skeletal ALP activity from hepatic ALP activity, we tested two established methods (heat inactivation and WGA precipitation) and a novel method, ConA precipitation. The organ-derived skeletal and hepatic ALP isoenzyme activities were used to compare these three methods with respect to linearity, isoenzyme separation, and precision. All three methods were linear, but the WGA and ConA methods afforded greater isoenzyme separation and precision. The relative extent of isoenzyme separation (i.e., the difference in percentage remaining skeletal and hepatic ALP isoenzyme activities) averaged 23, 40, and 47% remaining ALP activity for the heat, WGA, and ConA methods, respectively. However, when these methods were applied to the quantitation of skeletal ALP activity in sera from 10 young and 10 adult beagles, the WGA method was found to be unacceptable because most of the results fell outside the range of the WGA assay calibrators (i.e., greater than 100% skeletal ALP activity). The heat and ConA methods showed that the amount of skeletal ALP activity in the beagle sera decreased with age, both as ALP activity per liter and as percentage of total serum ALP activity (p less than 0.001 for each). Skeletal ALP activity levels determined by ConA were correlated with values determined by heat inactivation (r = 0.87, p less than 0.001) but not with WGA-determined levels (r = 0.26). Intestinal ALP activity was detected in only 1 of these 20 sera. We conclude that ConA precipitation can be used for quantitation of skeletal ALP activity in beagle serum.

Two biochemical indices of mouse bone formation are increased, in vivo, in response to calcitonin

In a series of four studies, adult female Swiss-Webster mice were used to measure the effects of salmon calcitonin on two biochemical indices of local and systematic bone formation: (1) skeletal alkaline phosphatase activity--in serum and in extracts of calvaria and tibiae, and (2) calvarial collagenase-digestible protein synthesis--measured, acutely, in vitro. Subcutaneous calcitonin doses ranged from 50 to 400 mU/mouse/day (0.95-18.1 U/kg/day), and treatment schedules were continuous (daily) for 2-14 days, acute, or intermittent (2 days/week for 6 weeks). The effects of calcitonin on these bone formation indices (skeletal alkaline phosphatase and collagenase-digestible protein synthesis) were biphasic with respect to dose and treatment time, being increased in response to short-term, low-dose treatment, but not long-term, continuous treatment. The effects of long-term intermittent calcitonin treatment were dose-dependent increases in skeletal alkaline phosphatase in calvaria and serum (r = 0.948, P less than 0.02, and r = 0.960, P less than 0.01, respectively).

Skeletal alkaline phosphatase specific activity is an index of the osteoblastic phenotype in subpopulations of the human osteosarcoma cell line SaOS-2

During continuous culture with serial passage, the human osteosarcoma cell line SaOS-2 showed a time-dependent decrease in skeletal alkaline phosphatase (ALP) activity. Because this was indicative of heterogeneity, subpopulations of SaOS-2 cells were isolated from replicate low-density cultures. The subpopulations were less heterogeneous and more stable (with respect to ALP) than the parent population. ALP specific activity in the subpopulations ranged from 0.05 to 2.3 U/mg protein, and cytochemical analyses indicated multiple steady-state levels of ALP activity per cell. The amount of ALP activity in SaOS-2 subpopulations was proportional to collagen production ([3H]proline incorporation into collagenase-digestible protein; r = .84, P less than .005), and to parathyroid hormone (PTH)-linked synthesis of cyclic adenosine monophosphate (cAMP) (r = .88, P less than .01). From these data, we inferred that ALP activity in SaOS-2 cells can provide a useful index of the osteoblastic phenotype, and that ALP activity, collagen production, and PTH-linked adenylate cyclase were coordinately regulated in these osteoblast-like osteosarcoma cells (ie, selection of subpopulations for ALP activity coselected for collagen synthesis and PTH-linked synthesis of cAMP). Further comparative studies showed that micromolar fluoride concentrations stimulated cell proliferation ([3H]thymidine incorporation into DNA) in low-ALP SaOS-2 subpopulations, but not in high-ALP cells (P less than .001), and that this differential sensitivity to fluoride was associated with an inverse correlation between fluoride-sensitive acid phosphatase and ALP activities (r = -.91, P less than .001).

Calcitonin has direct effects on 3[H]-thymidine incorporation and alkaline phosphatase activity in human osteoblast-line cells

Calcitonin had direct and dose-dependent actions on human osteoblast-line cells (in serum-free monolayer culture) to increase cell proliferation and alkaline phosphatase activity/mg cell protein. Salmon calcitonin increased (human osteosarcoma) SaOS-2 cell proliferation, as evidenced by dose-dependent increases in 3[H]-thymidine incorporation into DNA (e.g., 153% of control after 20 h exposure at 0.1 nM, P less than 0.01), and MTT (thyzolyl blue) reduction/deposition (e.g., 161% of control after 72 h exposure at 0.03 nM). Continuous exposure was not required to elicit these proliferative responses. These effects were not unique to salmon calcitonin or to SaOS-2 cells. Similar effects were seen with human calcitonin (but not heat-inactivated human calcitonin) and with (human osteosarcoma) TE-85 cells and human osteoblast-line cells prepared from femoral heads. In addition to effects on cell proliferation, calcitonin also increased alkaline phosphatase-specific activity in SaOS-2 cells (e.g., 180% of control after 72 h of exposure to 0.1 nM salmon calcitonin, P less than .005).

Absence of carbamazepine-induced hyponatremia among patients also given lithium

Of 33 chronically psychotic patients in a state hospital, 17 received carbamazepine, 13 received carbamazepine and lithium, and three received carbamazepine and then the combination. There was a significant difference in serum sodium level between the patients receiving carbamazepine alone (mean +/- SD = 138.4 +/- 4.3 meq/liter) and those also receiving lithium (141.8 +/- 1.6 meq/liter). (A similar difference was seen for the patients who received the two treatments serially.) Age, sex, diagnosis, age at diagnosis, seizure disorder, antipsychotic drugs, and serum carbamazepine level did not explain this difference. The protection against hyponatremia provided by the carbamazepine-lithium combination occurred despite lithium's tendency to increase polyuria.

A short screening device for identification of cerebral dysfunction in children

Many psychologists have been interested in the development of a screening battery for cerebral dysfunction. The purpose of the present study was to identify a short screening battery, drawn from the Halstead-Reitan Battery, that had a high degree of accuracy in differential identification of brain-damage and normal children. Fifty brain-damaged children and 50 controls (age 9-14 years) were identified and subdivided into two groups of 25 children in each category. The data based on the first pair of groups (25 brain-damaged and 25 control children) were processed with a discriminant analysis with linear transformation of the results, and a weighted screening index was developed based on eight measures. This screening index had an accuracy rate of 92% in differentiating the brain-damaged subjects from the controls. The screening index then was applied to the validational groups (25 brain-damaged and 25 normal children), and an 86% accuracy rate was achieved. Computation of the screening index, which requires less than an hour of testing, is illustrated in this paper.