CAMKK2 is upregulated in primary human osteoarthritis and its inhibition protects against chondrocyte apoptosis

OBJECTIVE

To investigate the role of calcium/calmodulin-dependent protein kinase kinase 2 (CAMKK2) in human osteoarthritis.

MATERIALS AND METHODS

Paired osteochondral plugs and articular chondrocytes were isolated from the relatively healthier (intact) and damaged portions of human femoral heads collected from patients undergoing total hip arthroplasty for primary osteoarthritis (OA). Cartilage from femoral plugs were either flash frozen for gene expression analysis or histology and immunohistochemistry. Chondrocyte apoptosis in the presence or absence of CAMKK2 inhibition was measured using flow cytometry. CAMKK2 overexpression and knockdown in articular chondrocytes were achieved via Lentivirus- and siRNA-mediated approaches respectively, and their effect on pro-apoptotic and cartilage catabolic mechanisms was assessed by immunoblotting.

RESULTS

CAMKK2 mRNA and protein levels were elevated in articular chondrocytes from human OA cartilage compared to paired healthier intact samples. This increase was associated with elevated catabolic marker matrix metalloproteinase 13 (MMP-13), and diminished anabolic markers aggrecan (ACAN) and type II collagen (COL2A1) levels. OA chondrocytes displayed enhanced apoptosis, which was suppressed following pharmacological inhibition of CAMKK2. Levels of MMP13, pSTAT3, and the pro-apoptotic marker BAX became elevated when CAMKK2, but not its kinase-defective mutant was overexpressed, whereas knockdown of the kinase decreased the levels of these proteins.

CONCLUSIONS

CAMKK2 is upregulated in human OA cartilage and is associated with elevated levels of pro-apoptotic and catabolic proteins. Inhibition or knockdown of CAMKK2 led to decreased chondrocyte apoptosis and catabolic protein levels, whereas its overexpression elevated them. CAMKK2 may be a therapeutic target to prevent or mitigate human OA.

Abstract P4-10-16: Neoadjuvant chemotherapy infusion in the arm ipsilateral to breast cancer increases the risk of lymphedema

Background: Neoadjuvant chemotherapy (NAC) has been administered to clinically axillary positive breast cancer (BC) patients. Current guidelines still recommend axillary lymphadenectomy (AL) in patients with persistent positive axillary lymph node disease. We aimed to evaluate the association of NAC and/or adjuvant chemotherapy (CT) infusion in the ipsilateral upper limb (IA) with AL and the occurrence of lymphedema (LE) secondary to BC treatment. Methods: A prospective cohort study of 683 women subjected to AL and treated with NAC and/or adjuvant CT for BC. The patients were evaluated before treatment, immediate and every 6 months after surgery. Cumulative incidence and population attributable risks of LE were calculated. Results: 8-year cumulative incidence of LE was 33.1%. NAC and CT infusion and infusion of >2 cycles into the IA respectively increased by 1.68, 1.67 and 1.78 times the risk of LE respectively (all P<0.01). LE could be avoided in 9.4% of cases if the CT infusion had not been administered in the IA. Conclusions: 33.1% of women developed LE. The risk of LE was increased among women who received CT in the IA. Avoidance of NAC or adjuvant CT in the IA could prevent 9% of the LE cases observed in this population.

Citation Format: Bergmann A, Bello MA, Thuker LC, Andrade MF, Bevilacqua JI. Neoadjuvant chemotherapy infusion in the arm ipsilateral to breast cancer increases the risk of lymphedema [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-10-16.

A review of neonatal tetanus in University of Maiduguri Teaching Hospital, North-eastern Nigeria

BACKGROUND

Neonatal tetanus is a vaccine preventable disease and is a leading cause of neonatal mortality in developing countries. The effectiveness of immunization and hygienic umbilical cord care practices in the prevention of the disease has been established.

OBJECTIVE

The objective of this study was to audit the scourge of neonatal tetanus in a tertiary health facility in a resource-limited setting.

MATERIALS AND METHODS

The study was a retrospective study. Case notes of neonates admitted with clinical diagnosis of tetanus into the Special Care Baby Unit (SCBU) between January 2009 and December 2010 were retrieved and evaluated to identify socio-demographic and clinical characteristics, mode of acquisition and severity of the disease, presence of co-morbidities, duration of hospital stay and outcome.

RESULTS

Most of the mothers had no tetanus immunization (66.7%) and the main social class of the children was class V (45.1%) and IV (41.2%), respectively. Only 29.4% of the mothers attended ante-natal care (ANC) while majority of the patients were delivered at home (94.1%). Half of the neonates presented with the severe form of the disease (51.0%). Sepsis is a prominent co-morbidity (59.2%). Morality was high with case fatality of 66.7%.

CONCLUSION

This high prevalence of neonatal tetanus with high mortality is not only disappointing but unacceptable in the 21(st) century. Therefore, all efforts must be re-focused on current preventive strategies while pursuing new areas such as slow-release mono-dose tetanus vaccine and school health programme as well as advocacy on political will for the sustainability of immunization programmes of women of child-bearing age.

Abstract P3-11-04: Male breast cancer: Overall survival in a single institution

Background: Male breast cancer is an uncommon disease and the therapy is mainly based on what is know from female breast cancer. Objective: To investigate the clinicopathologic characteristics of male breast cancer and the overall survival in a single institution.

Methods: The clinical data and survival status of 75 male breast cancer treated in a Brazilian public cancer hospital from 2000 to 2009 were collected. The association with clinicopathological characteristics and overall survival was analyzed using Kaplan-Meier curves and the Cox proportional hazards regression (enter method) was used to assess survival differences after adjusting for confounders. The study was approved by National Cancer Institute Research and Ethics Committee (number 128/11).

Results: The median patient age was 64 years (range 33–86). Estrogen receptor (ER) was positive in 58 (77.3%) patients, while progesterone receptor (PR) were positive in 47 (62.7%). Histology type was ductal infiltrant carcinoma for 57 (76.0%) and 51 (68.0%) patients underwent surgery. The median follow-up period was 43,1 months (range 2.7–147.8). The median survival from the diagnosis of breast cancer was 97.0 months (95%CI 53.6 −140.4) with a 61.7% 5-year overall survival (OS). In the final Cox regression model, independent factors associated with increased risk of death were metastasis at diagnosis (HR = 18.1; 95%CI: 5.9–55.2), ≥ 65 years old (HR = 4.3; 95%CI: 1.7–10.5); tumor stages ≥ IIb (HR = 3.5; 95%CI: 1.3–9.7) and smoking (HR = 1.6; 95%CI: 1.04–2.6).

Conclusions: Invasive ductal carcinoma is the main pathologic type. The median survival from the diagnosis of breast cancer was 97.0 months and metastasis at diagnosis, patient age, tumor stage and smoking are independent prognostic factors.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-11-04.

Abstract P6-07-44: Overall survival and the prognostic factors among women with infiltrating lobular carcinoma of the breast in National Cancer Institute of Brazil

BACKGROUND: The infiltrating lobular carcinoma (ILC) comprises approximately 10% of breast cancers and appears to have a distinct biology. Because it is less common than infiltrating ductal carcinoma (IDC), there are less data published regarding about their clinical outcomes. This study estimates survival rates in women with infiltrating lobular carcinoma of the breast, diagnosed between 2000 to 2009 that had undergone treatment in the National Cancer Institute of Brazil.

OBJECTIVES: Analyze overall survival and the main prognostic factors among women with infiltrating lobular carcinoma of the breast, diagnosed from 2000 to 2009 that had undergone treatment in the National Cancer Institute of Brazil.

MATERIALS AND METHODS: The survival curves were obtained in a hospital cohort of 843 patients with infiltrating lobular carcinoma of the breast diagnosed and treated between 2000 to 2009. The study variables were: age, race, tobacco, alcohol consumption, tumor-related variables, and treatment-related variables. Survival functions were calculated by the Kaplan-Meier method.

RESULTS: The mean follow up time was 64,27 months (sd 33,76), with 30,2% of deaths occurred in the period where the mean patients age was 58,58 years (sd 13,22). The overall survival (OS) was 105,61 months (95% CI, 101,68 to 109,54). The OS for patients with 4 or more positives axillary lymph nodes was 91,66 months (95% CI, 83,19 to 100,13; p < 0,0001) worse than patients with no positive axillary lymph node, where the overall survival was 124,26 months (95% CI, 119,41 to 129,12; p < 0.0001). The OS in patients with estrogen receptor positive was 109,05 months (95% IC, 104,83 to 113,28; p < 0.001) whereas in patients with hormone estrogen receptor negative, the OS was 81,75 months (95% CI, 69,93 to 93,58; p < 0,0001). Among smokers patients, the OS was 97,46 months (95% CI, 90,80 to 104,12; p = 0,012) and for no smoking patients, the OS was109,01 months (95% CI, 104,24 to113,79; p = 0,012). Patients in stage 1 and 2 show an mean overall survival of 126,76 months (95% CI, 122,77 to130,75; p < 0.0001) and patients in stage 3 and 4 show a worse overall survival with mean 74,61 months (95% CI, 68,59 to 80,62; p < 0.0001). The patients younger than 40 years old had worse overall survival, with mean 88,88 months (95% C, 72,98 to 104,72; p = 0.032) than those with more than 40 years old, where the mean was 106,77 months (95% CI, 102,74 to 110,79; p = 0,032). The consumption of alcoholic beverages and pleomorphic histological variant showed no statistically significant difference in overall survival.

CONCLUSION: The mean follow up time was 64,27 months with 30,2% of deaths occurred in the period. The overall survival (OS) was 105,61 months. The OS was asssociated with axillary involvement, estrogen and progesterone receptor hormone, age and tobacco.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-07-44.

Temporal evolution of linear alkylbenzene sulfonates and heavy metals in sludge from wastewater treatment plant

Five homologues of linear alkylbenzene sulfonates (LAS)-LAS C-10, LAS C-11, LAS C-12, and LAS C-13 and total LAS-were monitored during a one-year period in primary, secondary, and digested sludge to evaluate their presence and temporal evolution. Extraction of LAS was carried out using microwaves energy, and determination was performed using high-performance liquid chromatographic- fluorescence (HPLC-FL). The results showed that concentrations of total LAS were between 9 337 mg/kg(-1) dry matter for primary sludge and 33.3 mg/kg(-1)(DM) for secondary sludge. Concentrations of total LAS were greater than 2 113 mg/kg(-1) in primary and digested sludge and were less than 260 mg/kg(-) in secondary sludge. On the other hand, the highest concentrations of LAS in primary sludge were found in summer, probably because of lack of rain during those months. Concentrations tend to be constant throughout the year in digested sludge. In addition heavy metals also were analyzed. Heavy metals, including zinc, copper, nickel, lead, and chromium are persistent environmental contaminants that cannot be destroyed. Biomagnification through the food-chain and potential accumulation in human tissues can cause both human health and environmental concerns. Concern regarding total heavy metal content of sludge limits sludge recycling for use on agricultural lands. This paper presents a comparative study of wastewater sludge that are going to be used as fertilizer based on the requirements of legislation proposed in the European Union. This research found that concentrations of total LAS in digested sludge are higher than the limits established in the proposed new draft.

Recurrent generalized tetanus: a case report

We describe recurrent generalized tetanus in a four-year-old unimmunized boy following recurrent suppurative otitis media (SOM) within an 11-month period. There are not many published reports on recurrent tetanus. We highlight the importance of both primary immunizations and the need for active immunization before discharge as the infection does not confer a lifelong immunity. The usefulness of booster doses of tetanus toxoid and missed opportunities for immunization are emphasized.

Floral morphology and development in Quillajaceae and Surianaceae (Fabales), the species-poor relatives of Leguminosae and Polygalaceae

BACKGROUND AND AIMS

Molecular phylogenies have suggested a new circumscription for Fabales to include Leguminosae, Quillajaceae, Surianaceae and Polygalaceae. However, recent attempts to reconstruct the interfamilial relationships of the order have resulted in several alternative hypotheses, including a sister relationship between Quillajaceae and Surianaceae, the two species-poor families of Fabales. Here, floral morphology and ontogeny of these two families are investigated to explore evidence of a potential relationship between them. Floral traits are discussed with respect to early radiation in the order.

METHODS

Floral buds of representatives of Quillajaceae and Surianaceae were dissected and observed using light microscopy and scanning electron microscopy.

KEY RESULTS

Quillajaceae and Surianaceae possess some common traits, such as inflorescence morphology and perianth initiation, but development and organization of their reproductive whorls differ. In Quillaja, initiation of the diplostemonous androecium is unidirectional, overlapping with the petal primordia. In contrast, Suriana is obdiplostemonous, and floral organ initiation is simultaneous. Independent initiation of five carpels is common to both Quillaja and Suriana, but subsequent development differs; the antesepalous carpels of Quillaja become fused proximally and exhibit two rows of ovules, and in Suriana the gynoecium is apocarpous, gynobasic, with antepetalous biovulate carpels.

CONCLUSIONS

Differences in the reproductive development and organization of Quillajaceae and Surianaceae cast doubt on their potential sister relationship. Instead, Quillaja resembles Leguminosae in some floral traits, a hypothesis not suggested by molecular-based phylogenies. Despite implicit associations of zygomorphy with species-rich clades and actinomorphy with species-poor families in Fabales, this correlation sometimes fails due to high variation in floral symmetry. Studies considering specific derived clades and reproductive biology could address more precise hypotheses of key innovation and differential diversification in the order.

Floral morphology and development in Quillajaceae and Surianaceae (Fabales), the species-poor relatives of Leguminosae and Polygalaceae

BACKGROUND AND AIMS

Molecular phylogenies have suggested a new circumscription for Fabales to include Leguminosae, Quillajaceae, Surianaceae and Polygalaceae. However, recent attempts to reconstruct the interfamilial relationships of the order have resulted in several alternative hypotheses, including a sister relationship between Quillajaceae and Surianaceae, the two species-poor families of Fabales. Here, floral morphology and ontogeny of these two families are investigated to explore evidence of a potential relationship between them. Floral traits are discussed with respect to early radiation in the order.

METHODS

Floral buds of representatives of Quillajaceae and Surianaceae were dissected and observed using light microscopy and scanning electron microscopy.

KEY RESULTS

Quillajaceae and Surianaceae possess some common traits, such as inflorescence morphology and perianth initiation, but development and organization of their reproductive whorls differ. In Quillaja, initiation of the diplostemonous androecium is unidirectional, overlapping with the petal primordia. In contrast, Suriana is obdiplostemonous, and floral organ initiation is simultaneous. Independent initiation of five carpels is common to both Quillaja and Suriana, but subsequent development differs; the antesepalous carpels of Quillaja become fused proximally and exhibit two rows of ovules, and in Suriana the gynoecium is apocarpous, gynobasic, with antepetalous biovulate carpels.

CONCLUSIONS

Differences in the reproductive development and organization of Quillajaceae and Surianaceae cast doubt on their potential sister relationship. Instead, Quillaja resembles Leguminosae in some floral traits, a hypothesis not suggested by molecular-based phylogenies. Despite implicit associations of zygomorphy with species-rich clades and actinomorphy with species-poor families in Fabales, this correlation sometimes fails due to high variation in floral symmetry. Studies considering specific derived clades and reproductive biology could address more precise hypotheses of key innovation and differential diversification in the order.

Floral morphology and development in Quillajaceae and Surianaceae (Fabales), the species-poor relatives of Leguminosae and Polygalaceae

BACKGROUND AND AIMS

Molecular phylogenies have suggested a new circumscription for Fabales to include Leguminosae, Quillajaceae, Surianaceae and Polygalaceae. However, recent attempts to reconstruct the interfamilial relationships of the order have resulted in several alternative hypotheses, including a sister relationship between Quillajaceae and Surianaceae, the two species-poor families of Fabales. Here, floral morphology and ontogeny of these two families are investigated to explore evidence of a potential relationship between them. Floral traits are discussed with respect to early radiation in the order.

METHODS

Floral buds of representatives of Quillajaceae and Surianaceae were dissected and observed using light microscopy and scanning electron microscopy.

KEY RESULTS

Quillajaceae and Surianaceae possess some common traits, such as inflorescence morphology and perianth initiation, but development and organization of their reproductive whorls differ. In Quillaja, initiation of the diplostemonous androecium is unidirectional, overlapping with the petal primordia. In contrast, Suriana is obdiplostemonous, and floral organ initiation is simultaneous. Independent initiation of five carpels is common to both Quillaja and Suriana, but subsequent development differs; the antesepalous carpels of Quillaja become fused proximally and exhibit two rows of ovules, and in Suriana the gynoecium is apocarpous, gynobasic, with antepetalous biovulate carpels.

CONCLUSIONS

Differences in the reproductive development and organization of Quillajaceae and Surianaceae cast doubt on their potential sister relationship. Instead, Quillaja resembles Leguminosae in some floral traits, a hypothesis not suggested by molecular-based phylogenies. Despite implicit associations of zygomorphy with species-rich clades and actinomorphy with species-poor families in Fabales, this correlation sometimes fails due to high variation in floral symmetry. Studies considering specific derived clades and reproductive biology could address more precise hypotheses of key innovation and differential diversification in the order.

Spectrofluorimetric determination of velnacrine in human serum and urine

A simple, sensitive and rapid spectrofluorimetric method to determine velnacrine, a cholinesterase inhibitor, has been developed and validated. The influence of pH, temperature, ionic strength, presence of excipients, metal ions and surfactants on the fluorescence intensity has been studied. The proposed method allows the determination of 5-100 ng ml(-1) of velnacrine in aqueous solution containing sodium acetate buffer (pH 5.6; 0.04 M) with lambda(excitation) 242 nm and lambda(emission) 359 nm. The detection and quantitation limits were 1.7 and 4.5 ng ml(-1) respectively. The method was successfully applied to the determination of velnacrine in human serum and urine.

Association between parasitic intestinal infections and acute or chronic diarrhoea in HIV-infected patients in Caracas, Venezuela

A cross sectional survey was conducted to determine the association between enteric parasites and diarrhoea in HIV-infected adults in Caracas. Three hundred and four patients were evaluated: 104 had acute diarrhoea, 113 chronic diarrhoea and 87 were controls. Isopora belli infection was associated with acute (P = 0.022) and chronic diarrhoea (P = 0.003), Entamoeba histolytica/dispar infection was also associated with both acute (P = 0.015) and chronic diarrhoea (P = 0.017). Strongyloides stercoralis (P = 0.003), and Cryptosporidium parvum (P = 0.017) infections were associated mainly with chronic episodes. Weight loss (P < 0.001), a non-infectious factor investigated, was significantly associated with diarrhoea. Eosinophilia, a laboratory parameter studied, was found to be associated with strongyloidiasis (P = 0.001), giardiasis (P = 0.001) and isoporiasis (P = 0.003). In summary, the presence of enteric parasites in HIV-infected patients from tropical urban areas with diarrhoea, with or without significant weight loss, must be considered. Similarly, eosinophilia might suggest parasitic infection in these patients.

Electrochemical oxidation at carbon paste electrode of tacrine and 1-hydroxytacrine and differential pulse voltammetric determination of tacrine in pharmaceuticals and human urine

The electrochemical oxidation of tacrine and its 1-OH-metabolite, has been studied by cyclic voltammetry and differential pulse voltammetry by using carbon paste electrodes. The peak current-concentration relationship was found to be linear up to 20 micrograms ml-1 with detection limits of 0.06 microgram ml-1 for tacrine and 0.18 microgram ml-1 for 1-OH-tacrine and quantitation limits of 0.20 microgram ml-1 for tacrine and 0.37 microgram ml-1 for 1-OH-tacrine. A method for determining tacrine by differential pulse voltammetry in pharmaceuticals and human urine, in the presence of 1-OH-tacrine, has been developed.

Spectrofluorimetric determination of cisatracurium and mivacurium in spiked human serum and pharmaceuticals

Spectrofluorimetric methods to determine cisatracurium and mivacurium are proposed and applied to the determination of both substances in human serum and to the determination of mivacurium in pharmaceuticals. The fluorimetric methods allow the determination of 5-500 ng ml(-1) of mivacurium in aqueous solutions and 5-500 ng ml(-1) of cisatracurium in water-acetonitrile solutions, both containing acetic acid-sodium acetate buffer (pH 5.5) with lambda(exc)=230 nm and lambda(em)=324 nm.

Spectrofluorimetric determination of tacrine in pharmaceuticals and spiked human serum

A spectrofluorimetric method to determine tacrine is proposed and applied to the determination of tacrine in human serum and pharmaceuticals. The fluorimetric method allows the determination of 1-70 ng ml-1 of tacrine in aqueous solutions containing acetic acid-sodium acetate buffer (pH 5.6) with lambda exc = 242 nm and lambda em = 362 nm.

Determination of beta-blocker drugs in pharmaceutical preparations by non-suppressed ion chromatography

A rapid and feasible chromatographic method for determining atenolol, metoprolol, alprenolol, oxprenolol, acebutolol and propranolol by non-suppressed ion chromatography is proposed. The mobile phase consisted of 50 mM nitric acid in an aqueous solution of 4% (v/v) acetonitrile. Detection limits are in the range 0.1-2.7 mg l-1. The method was successfully applied to the determination of beta-blockers in several pharmaceutical formulations.

Loss of maternally-acquired measles antibody during infancy in Ilorin, Nigeria

In a study of the prevalence of measles antibody in infants aged 1-9 months detectable antibody was present in 32 per cent. Prevalence was highest in the 4-7 week age group and dropped rapidly with increasing age. In infants 28-35 weeks old, only 7 per cent had detectable antibody. Logistic regression analysis showed that by the end of the seventh month of life only 10 per cent would carry antibody against measles.

Size and metabolic properties of fibers in rat fast-twitch muscles after hindlimb suspension

Hindlimb suspension (HS) results in whole muscle atrophic and metabolic changes that vary in magnitude in different hindlimb muscles. The present study was designed to investigate these effects in single fibers. Fiber type and size and the activities of two metabolic marker enzymes were determined in a deep (close to the bone) and a superficial (away from the bone) region of the medial gastrocnemius (MG) and the tibialis anterior (TA) of control (CON) and 28-day HS adult female rats. Fibers were classified as dark or light adenosinetriphosphatase (ATPase) based on their qualitative staining reaction for myosin ATPase following alkaline preincubation. Fiber area and succinate dehydrogenase (SDH) and alpha-glycerophosphate dehydrogenase (GPD) activities were determined in tissue sections by use of an image analysis system. After 28 days of HS, the mean body weights of the CON and HS were similar. MG atrophied 28%, whereas TA weight was maintained in the HS. Both dark and light ATPase fibers in the deep region of the MG had smaller cross-sectional areas following HS, with the atrophic response being approximately twice as great in the light ATPase fibers. No significant changes in fiber type composition in either muscle or in fiber sizes in the superficial region of the MG or in either region of the TA were observed. Mean SDH activities of both fiber types were significantly lower in the MG and TA following HS. In contrast, mean GPD activities were either increased or maintained in light and dark ATPase fibers of both muscles in HS. Changes in SDH and GPD activity could not be directly linked to changes in fiber cross-sectional area. In summary, these data suggest an independence of the mechanisms determining muscle fiber size and metabolic adaptations associated with HS.

Predictability of skeletal muscle tension from architectural determinations in guinea pig hindlimbs

The maximum tetanic tension (Po) generated by a skeletal muscle is determined by its functional cross-sectional area (CSA) and its specific tension (tension/CSA). Measurements of average fiber length (normalized to a sarcomere length of 2.2 micron), muscle mass, and approximate angle of pinnation of muscle fibers within a muscle were taken from 26 different guinea pig hindlimb muscles and were used to calculate CSA. The specific tension was assumed to be 22.5 N X cm-2 and was used to determine the estimated Po of each muscle studied. In a second group of guinea pigs the in situ Po of 11 selected hindlimb muscles and muscle groups were determined. Estimated and measured Po values were found to have a strong linear relationship (r = 0.99) for muscle and muscle groups tested. The specific tension of the soleus, a homogeneously slow-twitch muscle, was shown to be approximately 15.4 N X cm-2 (P less than 0.01). Therefore, in our hands a specific tension value of 22.5 N X cm-2 appears to be a reasonable value for all mixed muscles studied in the guinea pig hindlimb and can be used to estimate their Po.

Architectural design and fiber-type distribution of the major elbow flexors and extensors of the monkey (cynomolgus)

Because the architectural and biochemical properties of skeletal muscle dictate its force, velocity, and displacement properties, the major extensors (triceps brachii) and flexors (biceps brachii, brachialis, and brachioradialis) of the elbow in a primate (cynomolgus, monkey) were studied. Functional cross-sectional areas (CSA) were calculated from muscle mass, mean fiber length (normalized to a 2.20 microns sarcomere length), and angle of fiber pinnation measurements from each muscle. Fiber-type distributions were determined and used as a gross index of the biochemical capacities of the muscle. The extensor group had a shorter mean fiber length (31 vs. 47 mm), a larger CSA (13 vs. 8 cm2), and a higher overall percentage of slow-twitch fibers (47 vs. 26%). Consequently, the elbow extensors had a relatively greater potential for force production and force maintenance than the flexors. In contrast, the flexors were designed to optimize their length-velocity potentials; i.e., they had relatively long fibers and a higher fast-twitch fiber composition than the extensors. These morphologic differences between antagonistic muscle groups should be considered when evaluating the motor control mechanisms regulating reciprocal movements about the elbow.