Radiological osteoarthritic knee joint changes in high school and collegiate sumo wrestlers: The observational study

We examined the effects of sumo on their knee joints, and investigated the relationship between radiological changes and knee joints symptoms, and the relationship between knee radiological changes and the physical characteristics of the wrestlers. Fifty-six high-school and 128 college freshman sumo wrestlers who belonged to the Japanese Sumo Federation. To evaluate radiological changes in the knee joints of high-school and college freshmen sumo wrestlers. They underwent routine radiographic examination of their knee joints and were instructed to answer a questionnaire regarding their knee symptoms as a medical check. The mean height, weight, body mass index (BMI), and sumo career/experience of the participants were 174.1 cm, 106.9 kg, 35.1 kg/m², and 7.9 years, respectively. Twenty-five high-school (44.6%) and 54 collegiate (42.2%) sumo wrestlers had some knee symptoms, which was significantly associated with sumo career as a risk factor. Five high-school (8.9 %) and 18 collegiate (14.1 %) sumo wrestlers had joint space narrowing. Considering the relationship between knee symptoms and radiological changes, significant correlations between osteophyte formation and bony sclerosis and knee symptoms were observed. According to the Kellgren-Laurence (KL) classification, 7 high-school (12.5%) and 26 collegiate (20.3%) sumo wrestlers were grade 2, 3, or 4. The risk factors of degenerative radiographic changes in the knee joints of the participants were heavyweight, large BMI, and older age. The knee osteoarthritic changes had already appeared in 12.5% high-school sumo wrestlers at the admission.     

Estradiol levels predict bone mineral density in male collegiate athletes: a pilot study

Objective Strenuous training commonly results in amenorrhoea, which contributes to bone loss in some female collegiate athletes. However, the impact of athletic training on endocrine function and bone mineral density (BMD) in male collegiate athletes is less well understood. The objective of the study was to investigate the specific endocrine determinants of BMD in male collegiate runners and wrestlers, including the potential impact of gonadal steroid levels. Design Cross‐sectional study. Patients Twenty‐six division I collegiate male athletes (wrestlers, runners and golfers). Measurements Main outcome measures included (i) BMD endpoints measured by dual energy x‐ray absorptiometry (DXA); (ii) endocrine end‐points: total and free oestradiol, total and free testosterone; (iii) body composition end‐points: lean and fat mass, measured by DXA; and (iv) exercise end‐points: maximal oxygen uptake (VO₂ max), number of miles run weekly and grip strength. Results Free and total oestradiol levels were important positive determinants of BMD. In contrast, total and free testosterone levels were not significant predictors of BMD at any skeletal site (except for free testosterone at the radius). In addition, lean body mass, % ideal body weight, total body weight, body mass index (BMI) and hours per week of resistance training were positive predictors of BMD. VO₂ max was a negative predictor of BMD. Mean BMD was higher at all skeletal sites in the wrestlers compared with the runners and a comparison group (golfers). Conclusions Our data suggest that oestradiol levels, BMI, and resistance training are more important determinants of BMD in male collegiate athletes than testosterone.     

Molecular epidemiology of Trichophyton tonsurans strains isolated in Japan between 2006 and 2010 and their susceptibility to oral antimycotics

Trichophyton tonsurans has been isolated among judo practitioners, wrestlers, and sumo wrestlers during an epidemic of tinea corporis and tinea capitis in Japan. A previous study using restriction fragment length polymorphism (RFLP) analysis of the non-transcribed spacer (NTS) region of the ribosomal RNA gene revealed that different sources for the causative fungus in epidemics among judo practitioners and among wrestlers. Many different fungal strains have since been isolated from practitioners of these sports. The present study evaluated fungal characteristics of strains newly isolated between July 2006 and December 2010 using this molecular method. PCR-RFLP analysis using MvaI and AvaI was performed on 263 strains, composed of 186 isolates from judo practitioners, 32 from wrestlers, 30 from sumo wrestlers, 5 from other sports, 7 from family members or friends of the sports practitioner patients, and 3 from sporadic (non-epidemic) cases. Four molecular types, NTS I, II, III, and VII were detected. Of these, NTS I was the most predominant, occurring in 243 of 263 strains (92.4%). All of the 30 strains isolated from sumo wrestlers were classified as NTS I, suggesting that the epidemic among sumo wrestlers originated from an earlier epidemic among judo practitioners. Thirteen strains were classified as NTS II; all were related to wrestling and were isolated mainly from Chubu and Kansai areas in the central part of Honshu island. NTS III was detected in 6 strains, and one strain classified as NTS VII was isolated from a sporadic case of tinea capitis in a Peruvian immigrant. The minimum inhibitory concentrations (MICs) of terbinafine, itraconazole, fluconazole, and griseofulvin on 10 strains of NTS I and NTS II and 4 strains of NTS III were examined; there were no differences in MIC between these molecular types.     

Immunologic evidence that the properties of human antihemophilic factor (factor VIII) are attributes of a single molecular species.

Preparations of human plasma rich in antihemophilic factor (AHF, factor VIII) correct the coagulative defect of classic hemophilic plasma, form precipitates with specific heterologous antiserum, and support aggregation of platelets by ristacetin and retention of platelets by columns of glass beads. Whether these various properties can all be attributed to a single molecular species is disputed. Antiserums were prepared in rabbits to partially purified AHF and to high molecular weight (MW) and low MW fragments separated by gel filtration through columns of agarose in the presence of 0.25 M calcium chloride. Antiserums to AHF and to its high or low MW fragments all inactivated procoagulant AHF in plasma or in preparations of AHF. In contrast, antiserums to AHF and its low MW fragment inactivated procoagulant AHF in the low MW fragment, while that against the high MW fragment lacked this property. Thus, the low MW fragment appeared to have some antigenic sites not present or accessible to the antiserum against the high MW fragment. In agreement with this, the low MW fragment did not block antiserum against the high MW fragment as tested by the capacity of this antiserum to inactivate functional AHF in plasma. These immunologic studies support the view that the various properties of preparations of human AHF are attributes of a single molecular species.     

The Prevalence of Asthma in an NCAA Division I Collegiate Athletic Program

Purpose. To determine the prevalence of asthma among all varsity athletes in a large National Collegiate Athletic Association (NCAA) Division I program. Methods. We retrospectively reviewed the medical records for all varsity athletes at The Ohio State University (OSU). Data were abstracted from patient charts that contained a Medical Health Questionnaire, annual physical examinations, and medical encounters by the OSU Sports Medicine staff. A diagnosis of asthma was defined by self-report of physician diagnosis as recorded in the medical record. Results. Overall, 130 of 763 (17.0%) athletes had a diagnosis of asthma. Females (67/280 or 23.9%) had a significantly higher prevalence of asthma than males (63/483 or 13.0%) (p value = 0.001). There was no significant difference in the prevalence of asthma between high- and low-ventilation sports. (p value = 0.201). Conclusions. The prevalence of asthma among varsity athletes at The Ohio State University is 17.0%, which is significantly higher than the reported prevalence of asthma in the general United States population between 18 to 24 years of age. More females had asthma in our study population than males. These data will allow for future studies and development of focused screening programs of collegiate athletes.     

Potential mechanism of action of intra-articular hyaluronan therapy in osteoarthritis: are the effects molecular weight dependent?

BACKGROUND: Hyaluronan, or hyaluronic acid (HA), is the major hydrodynamic nonprotein component of joint synovial fluid (SF). Its unique viscoelastic properties confer remarkable shock absorbing and lubricating abilities to SF, while its enormous macromolecular size and hydrophilicity serve to retain fluid in the joint cavity during articulation. HA restricts the entry of large plasma proteins and cells into SF but facilitates solute exchange between the synovial capillaries and cartilage and other joint tissues. In addition, HA can form a pericellular coat around cells, interact with proinflammatory mediators, and bind to cell receptors, such as cluster determinant (CD)44 and receptor for hyaluronate-mediated motility (RHAMM), where it modulates cell proliferation, migration, and gene expression. All these physicochemical and biologic properties of HA have been shown to be molecular weight (MW) dependent. OBJECTIVE: Intra-articular (IA) HA therapy has been used for the treatment of knee osteoarthritis (OA) for more than 30 years. However, the mechanisms responsible for the reported beneficial clinical effects of this form of treatment remain contentious. Furthermore, there are a variety of pharmaceutic HA preparations of different MW available for the treatment of OA, but the significance of their MWs with respect to their pharmacologic activities have not been reviewed previously. The objective of the present review is to redress this deficiency. METHODS: We reviewed in vitro and in vivo reports to identify those pharmacologic activities of HA that were considered relevant to the ability of this agent to relieve symptoms and protect joint tissues in OA. Where possible, reports were selected for inclusion when the pharmacologic effects of HA had been studied in relation to its MW. In many studies, only a single HA preparation had been investigated. In these instances, the experimental outcomes reported were compared with similar studies undertaken with HAs of different MWs. RESULTS: Although in vitro studies have generally indicated that high MW-HA preparations were more biologically active than HAs of lower MW, this finding was not confirmed using animal models of OA. The discrepancy may be partly explained by the enhanced penetration of the lower MW HA preparation through the extracellular matrix of the synovium, thereby maximizing its concentration and facilitating its interaction with target synovial cells. However, there is accumulating experimental evidence to show that the binding of HAs to their cellular receptors is dependent on their molecular size; the smaller HA molecular species often elicits an opposite cellular response to that produced by the higher MW preparations. Studies using large animal models of OA have shown that HAs with MWs within the range of 0.5 x 10(6)-1.0 x 10(6) Da were generally more effective in reducing indices of synovial inflammation and restoring the rheological properties of SF (visco-induction) than HAs with MW > 2.3 x 10(6) Da. These experimental findings were consistent with light and electron microscopic studies of synovial membrane and cartilage biopsy specimens obtained from OA patients administered 5 weekly IA injections of HA of MW = 0.5 x 10(6)-0.73 x 10(6) Da in which evidence of partial restoration of normal joint tissue metabolism was obtained. CONCLUSIONS: By mitigating the activities of proinflammatory mediators and pain producing neuropeptides released by activated synovial cells, HA may improve the symptoms of OA. In addition, HAs within the MW range of 0.5 x 10(6)-1.0 x 10(6) Da partially restore SF rheological properties and synovial fibroblast metabolism in animal models. These pharmacologic activities of HA could account for the reported long-term clinical benefits of this OA therapy. However, clinical evidence has yet to be described to support the animal studies that indicated that HAs with MW > 2.3 x 10(6) Da may be less effective in restoring SF rheology than HAs of half this size.     

Isolation and partial characterization of human low molecular weight protein associated with pulmonary surfactant

A low molecular weight (MW) protein was isolated from the bronchoalveolar lavage fluid of a patient with alveolar proteinosis. The protein was isolated on DEAE-cellulose and CM-cellulose columns by a cross-reaction with the monoclonal antibody against pig low MW protein (15 kDa) used as a marker. Acidic ethanol-soluble proteins obtained from the fractions eluted by 0.09 to 0.16 M NaCl concentration from the CM-cellulose column migrated mainly as a 15-kDa band in the SDS-PAGE system without urea but mainly as a 5-kDa band in a system with 8 M urea. The isoelectric point of the protein was pH 10 to 11, and it contained a large proportion of hydrophobic amino acids (72%), especially leucine (17%). The arginine content was also high (9%). Two monoclonal antibodies were raised against this low MW protein, and immunohistochemical studies revealed that the antigen was located in the inclusions of alveolar wall cells in normal lungs and in lungs from a patient with alveolar proteinosis. These results indicate that the low MW protein originates from lamellar inclusions of alveolar wall cells (possibly type II epithelial cells) and is secreted into alveolar spaces.     

Early Cardiovascular Mortality in Professional Football Players: Fact or Fiction?

Present data about the increased incidence of early cardiovascular disease and mortality in National Football League (NFL) players is conflicting. These findings are particularly concerning given the escalating weight of current football players at the high school, collegiate, and professional levels. Recent studies have confirmed that heavier former NFL linemen have an increased prevalence of cardiovascular disease compared with an age- and sex-matched reference population. Former linemen had a higher prevalence of obesity, lower high-density lipoprotein cholesterol, increased left ventricular mass and left atrial area, and the metabolic syndrome, compared with nonlinemen. There have been sparse data on the cardiovascular health of current players. A recent analysis of one team demonstrated that the cardiometabolic syndrome and its individual components were significantly more common in linemen versus nonlinemen. Because current heavier NFL players already have evidence of the cardiometabolic syndrome and its individual markers, careful medical evaluation of former and active players is warranted to reduce their risks. This medically and ethically indicated intervention, however, might limit interpretation of future longitudinal studies designed to assess mortality endpoints.     

Prophylactic valacyclovir to prevent outbreaks of primary herpes gladiatorum at a 28-day wrestling camp

Herpes gladiatorum (HG) plagues the sport of wrestling, especially in high school wrestlers and summer camps they attend. This study evaluated the usage of valacyclovir to prevent acquisition of primary HG, due to herpes simplex virus type 1 (HSV-1), in high school wrestlers at a 28-day wrestling camp. At the beginning and end of camp, IgM and IgG anti-HSV-1 antibodies were collected. Out of 332 male wrestlers, aged 13-20, who entered camp, 94 elected to participate in blood sampling. Sixty-four were on antiviral medication. Among the 94 wrestlers, 28 (29.8%) had positive IgG anti-HSV-1 titers. Of this group, 66 of 94, were HSV-1 IgG seronegative. At the end of camp, 55 of these original seronegative individuals elected to participate in blood sampling and none had detectable IgM anti-HSV-1 and -2 antibodies. Compared to previous years without antiviral usage, introducing prophylactic valacyclovir reduced clinical HG outbreaks by 87% at this 28-day wrestling camp. Due to the high prevalence of this virus in high school wrestlers, serological testing should be done at the beginning of each season. HSV-1 seropositive individuals should consider being on antiviral medication throughout the season to minimize the risk of transmitting the virus to other wrestlers.     

心率变异性和应激激素基础水平在评价运动致应激中的价值

目的:探讨心率变异性(HRV)和应激激素在运动致应激中的价值和应用方法。方法:在大运动量训练阶段(共5周),跟踪监测30例摔跤运动员催乳素、皮质醇等激素血清基础水平及HRV变化。结果:通过聚类分析,受试者的激素血清基础水平变化特点被划分为催乳素变化敏感类(12例)和皮质醇变化敏感类(18例),且两类受试者的HRV均呈现下降的变化趋势。结论:在评价运动致应激时,应激激素血清基础水平变化存在明显的个体差异;HRV具有反应灵敏、个体差异影响小、与运动要素关联度高等应用价值,应作为运动训练监控的常规指标。     

Sample pre-treatment determines the clinical usefulness of acid-labile subunit immunoassays in the diagnosis of growth hormone deficiency and acromegaly

OBJECTIVE: The usefulness of measuring the GH-dependent acid-labile subunit (ALS) in the management of GH deficiency (GHD) and acromegaly remains in question and is investigated in this study, comparing several different immunoassays for ALS. METHOD: We compared the diagnostic accuracy of a commercially available polyclonal Ab-based ELISA with SDS pre-treatment (SDS-ELISA) with a monoclonal Ab-based immunofluorometric assay, using two unfolding methods (urea (UREA) and Glycine-HCl (Gly)). The corresponding molecular weight (MW) of ALS and IGFBP-3 immunoreactivity was determined. The clinical usefulness of each assay was examined in adult GH disorders. RESULTS: ALS was lower in GHD and higher in acromegaly using all assays. In GHD, UREA had higher sensitivity and specificity than SDS-ELISA (59 and 69% versus 41 and 51% respectively). In acromegaly, sensitivity and specificity was 94 and 87% for UREA, 81 and 36% for Gly, and 44 and 44% for SDS-ELISA. After UREA, immunoreactivity for ALS and IGFBP-3 eluted at their predicted free MW using size-exclusion chromatography, whereas ALS immunoreactivity in SDS (300-600 kDa) and Gly (250-500 kDa) was at a high apparent MW consistent with aggregation. CONCLUSION: The diagnostic accuracy of ALS varies with assay choice and pre-treatment modality. UREA, which results in migration of ALS at the expected MW on a sizing column, has the highest specificity and sensitivity. Thus, if measured in an assay in which ALS is unfolded without aggregation, ALS is a clinically highly useful parameter for the assessment of GH.     

Consequences of sport training during puberty.

Growth at puberty depends on one's genetic potential, nutritional status and a series of hormones. Energy expenditure may modify the effects of these three factors on the linear growth rate and the relative proportions of fat-free and fat mass. Participation in sports where weight control is not required does not seem to affect pubertal timing or alter linear growth rate. The growth and maturation of athletes in weight control sports have the additional burden of energy output greater than intake; however, in only a minority the energy deficit is great enough to slow growth and maturation. Studies focusing on male wrestlers and female gymnasts are reviewed. In the wrestlers the hormonal picture is consistent with mild-to-moderate GH resistance and perhaps mild maturational delay, especially in the lower weight classes. The deficits in lean body mass and fat mass "catch-up" quickly following the end of training and competitive season. The situation with the gymnasts is somewhat different, the goal being to develop muscular strength within a shorter and lighter physique. Marked under-nutrition can keep these adolescents pre-pubertal for many years of training and competition. Whether subsequent growth is disproportionate or not remains indeterminate, but the marked delay in the onset of estrogen action can permanently cause the skeleton to be under-mineralized. In conclusion, most athletes continue to track along the centiles of their genetic potential. To define the mechanisms of growth and maturational delay one must longitudinally study children in weight-control sports.     

Effect of bone-derived growth factor on DNA, RNA, and proteoglycan synthesis in cultures of rabbit costal chondrocytes

Calvariae and chondrocytes in culture have been reported to release growth factors which stimulate bone and cartilage growth respectively. In the present studies, we examined the effects of bone-derived growth factor (BDGF) on DNA, RNA and proteoglycan synthesis in cultured rabbit chondrocytes. Two partially purified fractions of BDGF were tested, one with an approximate molecular weight (MW) of 20-30,000 and with greater activity on calvarial DNA labeling (BDGF I) and another with an approximate MW 6-13,000 and greater activity on bone collagen labeling (BDGF II). Both fractions had a similar effect and increased the incorporation of -3H-uridine into acid insoluble residues in chondrocytes and the incorporation of 35SO4(2-), 3H-glucosamine and 3H-serine into proteoglycans. However, BDGF II had a greater stimulatory effect on the incorporation of 3H-thymidine than BDGF I. These findings suggest that factor(s) released by bone cells are capable of stimulating cartilage metabolism and growth.     

Standard aggregating media to test the "aggregability" of rat red blood cells

Rat red blood cells (RBC) exhibit low aggregation tendency in autologous plasma and in standard aggregating media (e.g., 3% Dextran 70; MW: 70 kD). In experimental studies performed on rats, 3% Dextran 70 was found to be an unsuitable suspending medium to test the "aggregability" of RBC in a standard medium. It has been observed that solutions of higher molecular weight polymers (i.e., dextran, MW: 500 kD; polyethylene glycol , MW: 35 kD; polyvinylpyrrolidone, MW: 360 kD), at low concentrations were strong aggregators for rat RBC. Among these polymer solutions 0.5% Dextran 500 and 0.75% polyvinylpyrrolidone 360 were found to be the most suitable suspending media, to distinguish between the aggregability of RBC from septic and control rats. Therefore, these two polymer solutions are recommended as the standard aggregating media for rat RBC, to test the RBC aggregability.     

Heparin inhibition of human vascular smooth muscle cell hyperplasia.

BACKGROUND: Vascular smooth muscle cell (VSMC) growth is responsible for intimal hyperplasia, a major cause of failure after vascular surgery and angioplasty. Heparin is the first described inhibitor of VSMC growth, but has not proved effective in the prevention of human intimal hyperplasia. Heparin is a heterogeneous substance, which may contain a mixture of components which differ in antiproliferative activity. Isolation of an active component may favourably influence its therapeutic profile. METHODS AND RESULTS: Growth of human VSMC cultured from operative specimens, assessed by cell counting and labelled thymidine incorporation, was used as a model of VSMC proliferation in intimal hyperplasia. Unfractionated (UFH) and low molecular weight (LMWH) heparins inhibit cell growth and thymidine uptake by human VSMCs in response to 15% foetal calf serum. UFHs are more active than LMWHs and this difference increases with increasing heparin dose. To confirm this effect, size-based fractions of heparin were prepared by gel permeation chromatography, and characterised by high performance liquid chromatography. High molecular weight fractions (MW > 21000) have higher activity than fractions of medium (MW 12000-21000) or low molecular weight (MW < 12000). These differences become more pronounced at higher dose, and are statistically significant at 100 micrograms/ml (Mann-Whitney, p < 0.05). CONCLUSIONS: The antiproliferative activity of heparin appears to be maximal in its high molecular weight component.     

Contactless experiments on individual DNA molecules show no evidence for molecular wire behavior

A fundamental requirement for a molecule to be considered a molecular wire (MW) is the ability to transport electrical charge with a reasonably low resistance. We have carried out two experiments that measure first, the charge transfer from an electrode to the molecule, and second, the dielectric response of the MW. The latter experiment requires no contacts to either end of the molecule. From our experiments we conclude that adsorbed individual DNA molecules have a resistivity similar to mica, glass, and silicon oxide substrates. Therefore adsorbed DNA is not a conductor, and it should not be considered as a viable candidate for MW applications. Parallel studies on other nanowires, including single-walled carbon nanotubes, showed conductivity as expected.     

Active and inactive renin in anephric man: a comparison of molecular weight studies with normal human plasma and the effect of a specific monoclonal anti-renin antibody

Measurements of active and inactive renin have been made in a group of six anephric patients and in 30 normal healthy volunteers. Plasma renin activity (PRA) was detected in all of the anephric patients but values were below the normal range. A trypsin-activatable totally inactive renin was present in the plasma of all six patients. In three patients, levels of inactive renin were greater than that found for the mean value of the control group. Gel filtration studies of anephric plasma revealed a degree of heterogeneity of molecular forms of active high molecular weight (HMW) renin. However, an active form of approximately 65,000 daltons was usually present. Inactive renin, partially purified from anephric plasma had an apparent molecular weight (MW) of 59,000 daltons. Affinity chromatography with H.77 Sepharose was used to purify active renin from anephric and normal plasma following treatment with trypsin. The increased PRA in plasma from both groups following trypsin was associated with a 56,000 daltons form indicating little, if any, change in MW upon activation. The active HMW forms and the activated inactive renin were all totally inhibited by a renin-specific monoclonal antibody raised against human kidney renin.     

Deacetylation of Chitosan: Material Characterization and in vitro Evaluation via Albumin Adsorption and Pre-Osteoblastic Cell Cultures

Degree of deacetylation (DDA) and molecular weight (MW) of chitosans are important to their physical and biological properties. In this study, two chitosans, HS (DDA = 73.3%) and AT (DDA = 76.8%), were deacetylated with 45% sodium hydroxide under nitrogen atmosphere at 80 °C or 90 °C for up to 120 min, to obtain two series of chitosans. The polymers produced were characterized for MW by gel permeation chromatography, DDA by titration and UV-vis methods, and crystallinity, hydrophilicity and thermal stability by X-ray diffraction, water contact angle and differential scanning calorimetry respectively. Films, made by solution casting in dilute acetic acid at ambient conditions, were evaluated for biological activity by albumin adsorption and the attachment and growth of a pre-osteoblast cell line. Chitosans with between 80–93% DDA’s (based on titration) were reproducibly obtained. Even though deacetylation under nitrogen was supposed to limit chain degradation during decetylation, MW decreased (by maximum of 37.4% of HS and 63.0% for AT) with increasing deacetylation reaction time and temperature. Crystallinity and decomposition temperature increased and water contact angles decreased with processing to increase DDA. Significantly less albumin was absorbed on films made with 93% DDA chitosans as compared with the original materials and the AT chitosans absorbed less than the HS chitosans. The cells on higher DDA chitosan films grew faster than those on lower DDA films. In conclusion, processing conditions increased DDA and influenced physicochemical and biological properties. However, additional studies are needed to unambiguously determine the influence of DDA or MW on in vitro and in vivo performance of chitosan materials for bone/implant applications.     

Heterogeneity of somatostatin like immunoreactivity (SLI) in extracts of porcine, canine and human pancreas

Four different extraction procedure representative of methods commonly employed in the isolation of somatostatin like immunoreactivity (SLI) were tested for their ability to extract large MW forms of SLI from porcine, canine and human pancreas. The yield of SLI and recovery of added somatostatin was much higher with methods involving traditional acid/ethanol extraction (methods I and II) than with methods involving boiling of tissues in water or 2 M CH3COOH (methods III and IV). Porcine and canine pancreas extracted by methods III and IV (but not methods I and II) revealed remarkable molecular heterogeneity upon gel filtration, but immuno-affinity-chromatography eliminated the largest forms. A component of approximately 3000 daltons was immunoabsorbable and resisted refiltration in 8 M urea. No large forms were detectable in human pancreas. The SLI peaks eluting at the position of synthetic somatostatin could be resolved into two components, one of which was lacking C-terminal immunoreactivity. It is concluded that the method of extraction as well as the species investigated and the specificity of the antisera employed will influence significantly the results of studies of the tissue forms of somatostatin.