Courtesy Authorship in Academic Surgery Publications

Importance

Courtesy authorship is defined as including an individual who has not met authorship criteria as an author. Although most journals follow strict authorship criteria, the current incidence of courtesy authorship is unknown.

Objective

To assess the practices related to courtesy authorship in surgical journals and academia.

Design, Setting, and Participants

A survey was conducted from July 15 to October 27, 2017, of the first authors and senior authors of original articles, reviews, and clinical trials published between 2014 and 2015 in 8 surgical journals categorized as having a high or low impact factor.

Main Outcomes and Measures

The prevalence of courtesy authorship overall and among subgroups of authors in high impact factor journals and low impact factor journals and among first authors and senior authors, as well as author opinions regarding courtesy authorship.

Results

A total of 203 first authors and 254 senior authors responded (of 369 respondents who provided data on sex, 271 were men and 98 were women), with most being in academic programs (first authors, 116 of 168 [69.0%]; senior authors, 173 of 202 [85.6%]). A total of 17.2% of respondents (42 of 244) reported adding courtesy authors for the surveyed publications: 20.4% by first authors (32 of 157) and 11.5% by senior authors (10 of 87), but 53.7% (131 of 244) reported adding courtesy authorship on prior publications and 33.2% (81 of 244) had been added as a courtesy author in the past. Although 45 of 85 senior authors (52.9%) thought that courtesy authorship has decreased, 93 of 144 first authors (64.6%) thought that courtesy authorship has not changed or had increased (P = .03). There was no difference in the incidence of courtesy authorship for low vs high impact factor journals. Both first authors (29 of 149 [19.5%]) and senior authors (19 of 85 [22.4%]) reported pressures to add courtesy authorship, but external pressure was greater for low impact factor journals than for high impact factor journals (77 of 166 [46.4%] vs 60 of 167 [35.9%]; P = .04). More authors in low impact factor journals than in high impact factor journals thought that courtesy authorship was less harmful to academia (55 of 114 [48.2%] vs 34 of 117 [29.1%]). Overall, senior authors reported more positive outcomes with courtesy authorship (eg, improved morale and avoided author conflicts) than did first authors.

Conclusions and Relevance

Courtesy authorship use is common by both first and senior authors in low impact factor journals and high impact factor journals. There are different perceptions, practices, and pressures to include courtesy authorship for first and senior authors. Understanding these issues will lead to better education to eliminate this practice.

See one, do one, but never teach one? An analysis of resident teaching assist cases under various levels of attending supervision

BACKGROUND

Surgical training has traditionally relied on increasing levels of resident autonomy. We sought to analyze the outcomes of senior resident teaching assist (TA) cases performed with a structured policy including varying levels of staff supervision.

METHODS

Retrospective review at a military medical center of TA cases from 2009 to 2014. The level of staff supervision included staff scrubbed (SS), staff present and not scrubbed (SP), or staff not present but available (NP). Operative variables were analyzed. An anonymous survey of residents and attendings at 6 military programs regarding experience and opinions on TA cases was distributed.

RESULTS

389 TA cases were identified. The majority (52%) were performed as NP. Operative times were shorter for NP cases (p < 0.05). Overall complication rate and length of stay were not different between groups (p > 0.05). Survey results demonstrated agreement amongst staff and residents that allowing selective NP was critical for achieving resident competence.

CONCLUSION

There were no identified adverse effects on intraoperative or postoperative complications. This practice is a critical component of training senior residents to transition to independent practice.

Plasma coadministration improves resuscitation with tranexamic acid or prothrombin complex in a porcine hemorrhagic shock model

BACKGROUND

Traumatic coagulopathy has now been well characterized and carries high rates of mortality owing to bleeding. A 'factor-based' resuscitation strategy using procoagulant drugs and factor concentrates in lieu of plasma is being used by some, but with little evidentiary support. We sought to evaluate and compare resuscitation strategies using combinations of tranexamic acid (TXA), prothrombin complex concentrate (PCC), and fresh frozen plasma (FFP).

METHODS

Sixty adult swine underwent 35% blood volume hemorrhage combined with a truncal ischemia-reperfusion injury to produce uniform shock and coagulopathy. Animals were randomized to control (n = 12), a single-agent group (TXA, n = 10; PCC, n = 8; or FFP, n = 6) or combination groups (TXA-FFP, n = 10; PCC-FFP, n = 8; TXA-PCC, n = 6). Resuscitation was continued to 6 hours. Key outcomes included hemodynamics, laboratory values, and rotational thromboelastometry. Results were compared between all groups, with additional comparisons between FFP and non-FFP groups.

RESULTS

All 60 animals survived to 6 hours. Shock was seen in all animals, with hypotension (mean arterial pressure, 44 mm Hg), tachycardia (heart rate, 145), acidosis (pH 7.18; lactate, 11), anemia (hematocrit, 17), and coagulopathy (fibrinogen, 107). There were clear differences between groups for mean pH (p = 0.02), international normalized ratio (p < 0.01), clotting time (CT; p < 0.01), lactate (p = 0.01), creatinine (p < 0.01), and fibrinogen (p = 0.02). Fresh frozen plasma groups had significantly improved resuscitation and clotting parameters (Figures), with lower lactate at 6.5 versus 8.4 (p = 0.04), and increased fibrinogen at 126 versus 95 (p < 0.01). Rotational thromboelastometry also demonstrated shortened CT at 60 seconds in the FFP group vs 65 seconds in the non-FFP group (p = 0.04).

CONCLUSION

When used to correct traumatic coagulopathy, combinations of FFP with TXA or PCC were superior in improving acidosis, coagulopathy, and CT than when these agents are given alone or in combination without plasma. Further validation of pure factor-based strategies is needed.

Ten years of mechanical complications of central venous catheterization in trauma patients

The study purpose was to determine the incidence of mechanical complications (MC) associated with central venous catheterization (CVC) and to evaluate their impact on outcomes. This was a retrospective review of trauma morbidity and mortality records at a Level I trauma center (1999 to 2009). Demographics and outcomes were extracted for all trauma patients with CVC. Patients developing MC were compared with those who did not. Four thousand eight hundred eighteen lines were placed in 2935 patients. Of these, 1.5 per cent (n = 73) had MC. A total of 64.4 per cent (n = 47) were pneumothoraces followed by arterial cannulation at 8.2 per cent (n = 6) and thrombosis at 6.8 per cent (n = 5). The rate of MC by access site was: subclavian 1.8 per cent (n = 52), internal jugular 1.2 per cent (n = 10), and femoral 0.3 per cent (n = 3) (P value for trend = 0.001). Change in management was required in 31.5 per cent (n = 23). Number of lines (P < 0.001), Injury Severity Score (P < 0.001), body mass index less than 20 kg/m(2) (P = 0.036), and chest Abbreviated Injury Score greater than 3 (P = 0.034) were significant predictors of MC. Patients with MC had a longer intensive care unit length of stay (18.8 ± 25.7 vs 11.4 ± 13.3; adjusted odds ratio, 5.75; 95% confidence interval, 2.24-9.25; P = 0.001). Incidence of MC was 1.5 per cent. Complications were clinically significant in 31.5 per cent and resulted in longer intensive care unit stays.

Individual variations in protective effects of experimentally formed salivary pellicles

Salivary proteins protect teeth against acid-induced softening and demineralization by forming a pellicle. However, little is known about individual, gender and ethnic variations in this effect. Therefore, we aimed to determine differences in protective effects of experimentally formed pellicles from 10 healthy young Scandinavians (3 women and 7 men) and 10 healthy young non-Scandinavians (4 women and 6 men) including Arabic, Persian, Pakistan, Indian, and Chinese subjects. Bovine enamel blocks, which were precoated with parotid and submandibular salivary proteins for 12 h, were exposed to an acidic solution with surface microhardness (SMH) determinations before and after. No change in SMH equalled 100% protection, whereas SMH corresponding to no protein coating equalled 0%. The results showed that experimentally formed pellicles from non-Scandinavians protected enamel better than pellicles from Scandinavians (p < 0.001). Within groups protective effects of pellicles formed from parotid and submandibular saliva were equal and subjects with high protection from parotid saliva pellicles also had high protection from submandibular saliva pellicles (r = 0.78; p < 0.001). Within groups considerable differences were obtained among individuals ranging from 25 to 51% protection. However, SDS-PAGE and HPLC did not reveal any systematic relation between saliva protein composition and protective effects, although slightly more of the SN-isoform of S-type cystatin was found in pooled parotid saliva from those non-Scandinavian subjects showing highest protection. We conclude that individual variations in experimental pellicle protection against erosive challenges exist and that such variations appear not to be due to differences in a single protein component.

Optimal Drinking Water Composition for Caries Control in Populations

Apart from the well-documented effect of fluoride in drinking water on dental caries, little is known about other chemical effects. Since other ions in drinking water may also theoretically influence caries, as well as binding of fluoride in the oral environment, we hypothesized that the effect of drinking water on caries may not be limited to fluoride only. Among 22 standard chemical variables, including 15 ions and trace elements as well as gases, organic compounds, and physical measures, iterative search and testing identified that calcium and fluoride together explained 45% of the variations in the numbers of decayed, filled, and missing tooth surfaces (DMF-S) among 52,057 15-year-old schoolchildren in 249 Danish municipalities. Both ions had reducing effects on DMF-S independently of each other, and could be used in combination for the design of optimal drinking water for caries control in populations.

Analyses of Pseudomonas aeruginosa Lectin Binding to α-Galactosylated Glycans

The specificity and binding capacity of the galactophilic lectin from the Gram negative bacterium Pseudomonas aeruginosa (PA-IL) was determined by solid phase measurements using galactosylated neoglycoproteins immobilized on microtiter plates. The bacterial lectin reacted with both short chain (monosaccharide) and long chain (pentasaccharide) glycoconjugates. Among the Galalpha1-XGal disaccharides, the highest affinity was observed towards the Galalpha1-3Gal structure. Raising the incubation temperature enhanced the lectin-polysaccharide agglutination, and it is suggested that binding to certain conformations of polysaccharides could vary between lectins with the same monocarbohydrate specificity and that this activity may, in part, be temperature dependent. Histochemical examination of lectin binding to different porcine tissues suggests a differential glycosylation of the carbohydrate antigens on endothelial cells in various parts of the vascular system. In the pancreas, PA-IL also adhered to the excretory ducts. These observations on PA-IL binding could be of importance both to determine infection foci in P. aeruginosa-mediated vacuities and to determine its role for pancreatic involvement in cystic fibrosis.

The effect of spironolactone on experimental periodontitis in rats

BACKGROUND

Elevated levels of tumour necrosis factor (TNF) have been found in patients with adult periodontitis. Animal studies have shown that TNF plays an important role in the pathogenesis of periodontitis. New findings suggest that the aldosterone-inhibitor spironolactone possesses an anti-TNF effect. The purpose of the study was to determine the anti-TNF effect of spironolactone in an endotoxic shock rat model and to disclose the effect of oral administration of spironolactone on the development of experimental periodontitis in rats.

METHODS

The study was divided in two parts. Part 1: oral administration of spironolactone (100 mg/kg) followed by intravenous lipopolysaccharide (1 mg/kg) infusion 45 min later. Blood samples were taken before and 90 min after lipopolysaccharide infusion to determine the TNF levels in spironolactone treated and non-treated rats. Part 2: oral administration of spironolactone [100 mg/(kg day)] starting 2 days prior to induction of experimental periodontitis established by peridental ligatures. Morphometrical and radiographical registrations of alveolar bone destruction were carried out to determine the effect of spironolactone on the progression of experimental periodontitis.

RESULTS

In part 1 the endotoxic shock model showed a significant reduction in TNF levels in the spironolactone-treated group compared to the non-treated group, suggesting that spironolactone acts as a TNF inhibitor. In part 2 spironolactone-treated rats did not demonstrate significantly less alveolar bone destruction compared to non-treated rats.

CONCLUSIONS

The insignificant effect of spironolactone treatment could be explained by the fast metabolism of spironolactone and that spironolactone does not completely inhibit TNF production in rats. Moreover, many other cytokines and mediators involved in alveolar bone destruction may account for the lacking response to spironolactone.

Effect of Saliva Composition on Experimental Root Caries

The aim of this study was to determine the effect of saliva composition on caries lesion development independently of the flow rate of unstimulated whole saliva (UWS) and other caries-related variables such as lesion progression time, oral hygiene level, and fluoride exposure. We hypothesized that this could be done by developing experimental root caries under carefully controlled conditions in situ in test subjects with UWS flow rates within a narrow window of normalcy. Fifteen female and 5 male subjects (66 +/- 6 years) were selected for the study according to their UWS flow rates between 0.2 and 0.4 ml/min. All subjects developed experimental root caries lesions during a 62-day period in which UWS as well as stimulated whole saliva (SWS) were repeatedly collected and analysed for flow rate, pH, buffer capacity, inorganic, and organic composition. Caries lesion development was determined by quantitative microradiography. The mean UWS flow rate was 0.30 +/- 0.05 ml/min. Significant negative correlations were obtained between UWS total phosphate concentration and mineral loss (DeltaZ; r(s) = -0.72, p < 0.001) and UWS total protein concentration and DeltaZ (r(s) = -0.70, p < 0.01). SWS and its constituents had only limited or no effect on DeltaZ. Qualitative UWS protein analysis (SDS-PAGE) revealed that subjects with low DeltaZ values had broader and more stained amylase bands than subjects with high DeltaZ values. These findings were confirmed quantitatively by HPLC. We conclude that, within a group of subjects with normal UWS flow rates, the UWS composition was more important for caries lesion development than the SWS composition. Furthermore, high UWS concentrations of phosphate, protein, and amylase were caries-protective.

Binding of Griffonia simplicifolia 1 isolectin B4 (GS1 B4) to alpha-galactose antigens

Glycoconjugates with terminal Galalpha1-3Galbeta1-4GlcNAc sequences (alpha-galactosyl epitopes, natural xenoreactive antigens) are present on various tissues in pigs and are recognized by human anti-alphagalactosyl (alphaGal) antibodies1. Hence xenotransplantation (pig-to-human) would trigger immune reactions involving complement activation and lead to the hyperactute rejection of the graft. Xenoreactive antigens are often studied by using the lectin Griffonia simplicifolia 1 isolectin B4 (GS1 B4), which shows high affinity to galactose. We here estimate the specificity of GS1 B4 for detecting various galactosyl epitopes by measuring lectin binding to neoglycoproteins, thyroglobulin and pig skeletal muscle. Enzyme linked lectin assays confirmed that GS1 B4 was highly specific to alpha-galactosylated neoglycoproteins while the lectin did not detect a beta-galactosylated ligand. The length of the sugar chains influenced the lectin-carbohydrate interaction. A monosaccharide linked to serum albumin showed higher lectin affinity than did neoglycoproteins with di- and tri-alpha-galactosyl epitopes. When the carbohydrate was extended, as in the xenoreactive pentasaccharide (Galalpha1-3Galbeta1-4GlcNAcbeta1-3Galbeta1-4Glc), the carbohydrate- lectin interaction was meagre. Not only the terminal, but also the subterminal sugar affected the lectin binding because the GS1 B4 affinity to Galalpha1-3Gal was much stronger than to Galalpha1-3GalNAc. In bovine and porcine thyroglobulin most alphaGal epitopes appear to be cryptic, but are unmasked by a heat denaturation. In pig skeletal muscle there was lectin reaction not only in the muscle capillaries, but also in the connective tissue and intracellularly in muscle fibres. In Western blots of isolated proteins from pig muscle at least three bands were strongly stained after incubation with lectin.

The buffer capacity and buffer systems of human whole saliva measured without loss of CO2

The buffer capacity of unstimulated (UWS) and stimulated (SWS) whole-mouth saliva involves three major buffer systems. The aim was to determine the buffer capacity of UWS and SWS at specific pH in the interval from pH 7.5 down to pH 3.0. The contribution of each of the buffer systems was also determined under conditions resembling those in the mouth. UWS and SWS were collected from 20 healthy volunteers; the saliva was collected under paraffin oil in order to avoid loss of CO2. The buffer capacity of UWS and SWS in samples with and without bicarbonate (HCO3-) and CO2 were measured at various pH by acid titration in a closed system at 36 C. The mean concentrations of the buffer systems in UWS (mean flow rate 0.55 ml/min) were 4.4 mmol/l HCO3-, 4.5 mmol/l phosphate (of which 1.3 mmol/l was present in the form of HPO4(2-)), 1876 microg/ml protein; the saliva pH was 6.8 and the P(CO2) 29.3 mmHg. The corresponding mean concentrations in SWS (mean flow rate 1.66 ml/min) were 9.7 mmol/l HCO3-, 3.8 mmol/l phosphate (of which 1.9 mmol/l was present in the form of HPO4(2-)), 1955 microg/ml protein; pH 7.2 and P(CO2) 25.7 mmHg, The highest buffer capacity of UWS and SWS was 6.0 and 8.5 mmol H+ /(1 saliva*pH unit) at pH 6.25, respectively. At saliva pH in the range from pH 7 down to pH 5, the following had significant impact on buffer capacity: the HCO3- concentration (p < 0.001), the flow rate (p < 0.01), and the pH of the saliva (p < 0.05). At acidic pH in the range from pH 5 down to pH 4, however, only the protein concentration had a significant impact on buffer capacity (p < 0.01).

Galalpha1-->4Gal-glycans are expressed on myofibrillar associated proteins

There is evidence that glycans carrying terminal galactose residues are differently expressed in the sarcoplasm of different muscle fiber types. In this study monoclonal antibodies directed against P blood group antigens Pk: Galalpha1-4Galbeta1-4Glcbeta- and P1: Galalpha1-4Galbeta1-4GlcNAcbeta- were used to detect terminal alpha-galactosylated glycoconjugates on muscle proteins. Electrotransfer of proteins, extracted from human masseter and biceps muscles, to nitrocellulose after polyacrylamide gel electrophoresis (PAGE) and incubation with anti-Pk (CD77) consistently showed two bands with apparent molecular weights of 66 kDa and 64 kDa. In fresh frozen muscle sections from some humans there was endothelial reaction with anti-CD77 in capillaries, venules and veins but not in arterioles and arteries. In muscle samples from other humans there was no staining of endothelial cells. Formalin-fixed human muscle displayed a CD77 reaction with highest accumulation of reaction product at the periphery of the fibers. This may be explained by the presence of Pk glycoconjugates on intermediate filaments in muscle fibers. In preparations of cat masseter muscle proteins the antibodies against P1Pk antigens reacted with a 170 kDa and a 55 kDa band while in preparations of cat biceps brachii only a 55 kDa band was reactive. The specificities of the antibodies were investigated by fluorescence-activated cell sorter (FACS), alpha- and beta-galactosidase digestion and inhibitory sugars. This study indicates that glycans carrying Galalpha1-4Galbeta1- epitopes are expressed on myofibrillar associated proteins.

Sirius red and acid fuchsin staining mechanisms

The purpose of the study was to investigate the staining mechanism of acid fuchsin and Sirius red. Acid (poly-glutamic acid), neutral (poly-hydroxyproline) and basic (poly-arginine, poly-histidine, poly-lysine) poly-amino acids, collagen types I, II and III, and arginine- and lysine-containing histones were used as test substances applied to nitrocellulose membranes as dot blots. Five micrometer sections of granulation tissue on slides were tested in parallel. Some dots and sections were treated with chloramine-T before staining with acid fuchsin and Sirius red and some with 1 M NaOH after staining. The acid and neutral poly-amino acids were not stained, but the basic amino acids polylysine and poly-arginine, poly-amino acids containing these basic amino acids and the histones and the collagens exhibited intense staining. Oxidative deamination by chloramine-T abolished the staining and 1 M NaOH removed the staining except in the case of poly-arginine. Tissue sections treated in the same way showed a considerable decrease in staining after oxidative deamination with chloramine-T; in particular, the staining of the smaller fibers was abolished. The staining was totally removed by destaining with 1 M NaOH. Therefore, acid fuchsin and Sirius red are not selectively bound to collagen; they are also bound to other proteins containing basic amino acids, and staining to a large extent is influenced by electrostatic forces. The staining seems not to be selective for collagen, and one must account for this when quantitative conclusions are drawn from collagen methods using these stains.

Dose response profiles of human growth hormone in subcutaneous wound chambers in rats

OBJECTIVE

To investigate dose response profiles of human growth hormone in soft connective tissue healing when it is given locally in subcutaneous wound chambers.

DESIGN

Placebo controlled parallel study.

SETTING

Institute of Medical Anatomy, Denmark.

MATERIAL

36 male Sprague Dawley rats, in three group of 12.

INTERVENTIONS

Stainless steel wire mesh cylinders 7 mm in diameter and 20 mm long were implanted subcutaneously in pairs in the upper and lower back on either side of the midline in three groups of male Sprague Dawley rats. Two groups were each given two different doses of growth hormone (group 1, 0.2 and 0.7 IU; and group 2, 0.02 and 2 IU) in two cylinders and vehicle alone in the two cylinders on the opposite side. Group 3 were given vehicle alone in two cylinders and needle puncture (sham) on the opposite side. Injections of growth hormone or vehicle (placebo) were given every three days for 16 days.

MAIN OUTCOME MEASURES

Body weight, weight of granulation tissue, and concentrations of hydroxyproline and aminoterminal propeptide of procollagen type III.

RESULTS

The dose response curves for weight of granulation tissue and deposition of collagen were upward convex (ANOVA p < 0.001 and 0.001, respectively). Growth hormone in doses of 0.2 and 0.7 IU stimulated formation of granulation tissue to means of 180% (95% confidence interval (Cl) 149% to 210%) and 174% (95% Cl 148% to 200%) more than in the placebo treated cylinders (group 3) (p < 0.05 and < 0.01, respectively). Doses of 0.2 and 2 IU, however, had less effect. The placebo cylinders in animals in groups 1 and 2 contained a mean of 157% (95% Cl 137% to 177%) more granulation tissue than the cylinders in group 3, indicating that locally applied growth hormone also had a systemic effect.

CONCLUSION

The clinical use of topical growth hormone in wound healing may be complicated by the relatively narrow therapeutic interval.

The protein effect on determination of DNA with Hoechst 33258

The present study was designed to afford a critical review of the effect of proteins on the Hoechst 33258 method for determination of DNA of crude homogenates. A considerable effect of proteins on the fluorescence was observed when the concentration exceeded 100 micrograms BSA equivalent protein. Below that value, practically no effect of proteins was noted. We used proteinase K to remove the proteins, but dilution of homogenates could be used as well. Moreover, we found that the concentration of the fluorochrome should be between 1 microgram and 2 micrograms when microgram levels DNA are to be determined.

Immunohistochemistry of the intercellular matrix components and the epithelio-mesenchymal junction of the human tooth germ

The immunohistochemical localization of heparan sulphate, collagen type I, III and IV, laminin, tenascin, plasma- and cellular fibronectin was studied in tooth germs from human fetuses. The lamina basalis ameloblastica or membrana preformativa, which separates the pre-ameloblasts from the pre-dentin and dentin, contained heparan sulphate, collagen type IV, laminin and fibronectin. Enamel reacted with antifibronectin, but the reaction varied depending on the type of fibronectin and the source of antibody. In early pre-dentin, collagen type I, laminin, tenascin and fibronectin were present. In late pre-dentin and dentin collagen type I was found in intertubular dentin and in the zone between enamel and dentin. The close relationship between collagen type I in dentin and fibronectin in immature enamel is interesting, as it may contribute to the stabilization of the amelodentinal interface. In dental pulp, collagen type IV and laminin were found in the endothelial basement membranes. Collagen type I and III, tenascin and fibronectin were localized to the mesenchymal intercellular matrix. The results of this study have supported the assumption that the lamina basalis ameloblastica is a basement membrane, and have lead to the suggestion that ameloblasts are producers of fibronectin or a fibronectin-like substance.

Influence of human growth hormone on granulation tissue formation, collagen deposition, and the aminoterminal propeptide of collagen type III in wound chambers in rats

The influence of growth hormone on granulation tissue formation was investigated in wire mesh cylinders implanted subcutaneously in rats. Two groups of 10 rats (study 1) and 1 group of 12 rats (study 2) were used for the investigation. Growth hormone, 0.02 and 0.2 IU (study 1), 0.05 and 0.2 IU (study 2), or vehicle only, was injected into the cylinders every third day for 16 days. In study 2, wound fluid was aspirated before injection of growth hormone and saved for later analysis of the aminoterminal propeptide of collagen type III. In both studies, growth hormone significantly increased the formation of granulation tissue and of total collagen content dose-dependently, whereas the relative amount of collagen was unaffected by growth hormone treatment. Wound fluid aminopropeptide increased significantly after implantation of the cylinders until day 7, before declining slightly, with no difference between the groups. We conclude that growth hormone stimulated granulation tissue formation and collagen deposition dose-dependently in the wound cylinders when injected every third day. The results suggest that growth hormone treatment does not cause excessive collagen deposition in newly formed granulation tissue.

Biotin carboxylases in mitochondria and the cytosol from skeletal and cardiac muscle as detected by avidin binding

Biotin carboxylases in mammalian cells are regulatory enzymes in lipogenesis and gluconeogenesis. In this study, endogenous biotin in skeletal and cardiac muscle was detected using avidin conjugated with alkaline phosphatase and applied in high concentrations to muscle sections. The avidin binding was subsequently visualized by histochemical demonstration of the alkaline phosphatase activity. All cardiac muscle cells showed high affinity for avidin with only the nuclei and the intercalated discs remaining unstained. In skeletal muscle a diffuse reaction could be detected in the sarcoplasm of the muscle fibres. A granular reaction was noted in the same fibres that showed activity for succinic dehydrogenase. The specificity of the coloured reaction product in the muscle sections was investigated and is suggested to be caused by avidin binding to biotin moieties in mitochondria and the cytosol. Mitochondrial and cytosolic preparations of skeletal muscle were electrophoresed in sodium dodecyl sulphate gels. After blotting and incubation with conjugated avidin, two bands with molecular weights of 75 kDa and 130 kDa respectively were evident in the mitochondrial preparation. It is suggested that the 75-kDa band represents comigration of the biotin-containing subunits of propionyl-CoA carboxylase and methylcrotonyl-CoA carboxylase. The 130-kDa band may represent the biotin-containing pyruvate carboxylase. In the cytosolic preparation a 270-kDa band was stained in blots that had been incubated with conjugated avidin; this band is suggested to represent acetyl-CoA carboxylase. A 190-kDa cytosolic band might be a cleavage product of acetyl-CoA carboxylase. We propose that using alkaline phosphatase-conjugated avidin it is possible to detect the mitochondrial and cytosolic biotin-dependent carboxylases in striated muscle.

Exaggerated abrasion/erosion of human dental enamel surfaces: a case report

An atypical, rapidly proceeding abrasion/erosion of the labial enamel surfaces of the maxillary and mandibular incisors and canines in a 27-yr-old man is reported. Ultrastructural examination of a replica of the teeth showed a practically structureless enamel surface both at the initial examination and after 12 months. However, at the end of the period, minor areas of dentin tubules became visible, indicating that a substantial loss of the tooth substance had taken place. The patient's occupation involved daily environmental contact with proteolytic enzymes. In vitro study of enamel exposed to one of the actual proteolytic enzymes showed dissolution of enamel substance, and it cannot be excluded that enzymatic decomposition of the organic enamel matrix is a contributing cause of the observed exaggerated loss of tooth substance.

Fucose expression in skeletal muscle: a lectin histochemical study

Binding sites for three fucose specific lectins, Aleuria aurantia agglutinin (AAA), Lotus tetragonolobus agglutinin (LTA) and Ulex europeus I agglutinin (UEA I), were investigated in sections from normal human and rat muscles, in muscle from patients with Duchenne muscular dystrophy (DMD) and in denervated and devascularized rat muscle. In normal human and rat muscle AAA detected fucosylated glycocompounds in the sarcoplasm, sarcolemma, interfibre connective tissue and vascular structures. In normal human muscle addition of fucose to the AAA incubation medium or treatment of the sections with formaldehyde followed by periodic oxidation before lectin incubation strongly inhibited the staining at all sites other than endothelial cells. In normal rat muscle the same staining procedures strongly inhibited the AAA binding at all sites other than the sarcolemma. Incubation with LTA resulted in a diffuse reaction around the vascular structures in rat muscle, while in human muscle a moderate, homogeneous staining was present in all muscle fibres. Treatment of the sections with formaldehyde and periodic acid before incubation with LTA resulted in strongly labelled muscle capillaries in both human and rat muscle. The only elements in the muscle tissues that were stained with UEA I were human endothelial cells. In denervated and devascularized rat muscle incubation with AAA revealed a novel fucose expression that appeared intracellularly in some necrotic fibres. The AAA-positive fucose residues in the sarcolemma of normal muscle fibres that were resistant to periodic acid oxidation could not be shown by AAA in denervated muscle. In DMD muscle a cryptic sarcolemmal fucose expression could be shown with AAA.(ABSTRACT TRUNCATED AT 250 WORDS)

The silver staining procedure of sodium dodecyl sulfate-gels may be accelerated by shortening fixation time

In most silver staining methods the first step in the staining of proteins separated after sodium dodecyl sulfate-polyacrylamide gel electrophoresis is a rather protracted fixation of the gels. Optimum fixation should be short, cause no background staining and effectively immobilize the proteins in the gel without masking the proteins for reaction with the staining solution. Further, the concentration of the fixing compounds should be as low as possible due to the potential toxicity of fixatives. Fixation for only 5 min with mixtures of very low concentrations of formaldehyde and glutaraldehyde in ethanol, or a solution of formaldehyde or glutaraldehyde in picric acid and ethanol, fulfill these demands, provided that the gels were prefixed in ethanol-acetic acid for 10 min. As a consequence of these results a fast and sensitive silver staining procedure is proposed.

Mosaic lectin and enzyme staining patterns in rat skeletal muscle

We compared the localizations of lectin binding and activity for myosin ATPase and succinic dehydrogenase in sections of the gracilis, soleus, and masseter muscles from 10- and 60-day-old rats. In the 60-day-old rats, incubation of the muscle sections with the lectins ConA, GS-II, HPA, and jacalin gave rise to a mosaic staining pattern, especially in the gracilis muscle, in which the same fibers were strongly stained for ConA, GS-II, and HPA, whereas the staining with jacalin in these fibers was weak, and vice versa. There was no correspondence in the staining patterns for the enzymes and the lectins. In the masseter muscle only GS-II gave rise to distinct differences in the staining intensity between muscle fibers. In 10-day-old rats all fibers in the muscles were moderately stained with ConA, HPA, and jacalin, whereas a chessboard staining pattern could be observed after incubation with GS-II. In an extract of hindleg muscle from 60-day-old rats there was strong affinity for ConA and HPA and weak affinity for GS-II and jacalin, as shown by dot-blotting. After electrophoresis and blotting to nitrocellulose membranes, three muscle protein bands with apparent molecular weights of 100,000, 90,000, and 43,000 showed affinity for ConA, HPA, and GS-II, whereas no bands were jacalin positive. The complex lectin staining pattern in skeletal muscle might be related to development, specialization, and function of the muscles.

Quantitative PAS assay of some carbohydrate compounds and detergents

A spectrophotometric method for determination of color development of glycocompounds subjected to PAS reaction was investigated with various carbohydrate compounds and related chemicals. The conditions of the oxidation with periodic acid was found to influence the amount of the colored Schiff dye produced. Mono- and di-saccharides (mannose, glucose and maltose) were PAS-negative. Glycogen was more reactive than dextran. When glycogen was hydrolyzed by amylase the intensity of the PAS product dropped until a certain limit probably reflecting the limit dextrin. The presence of proteins (albumin) or electrolytes (NaCl) did not influence the PAS reaction. Many non-ionic detergents commonly used in membrane biology such as alkyl glycosides and gluco-methyl alkanamides were strongly PAS-positive and so was the anionic detergent SDS while the zwitterionic detergents tested, such as CHAPS and CHAPSO, were PAS-negative. The color development of the spectrophotometric PAS reaction showed linearity with the concentration of a simple glycoprotein solution (peroxidase) and a complex solution (bovine serum). By the PAS reaction it was also possible to measure the content of soluble and membrane bound carbohydrate compounds in a pellet of liver cell membranes. We find that the PAS reaction is sensitive and reliable for quantitative estimations of complex carbohydrates as well as soluble and membrane-bound carbohydrate compounds. The latter should be treated with PAS-unreactive zwitterionic detergents.

Changes of soluble glycoproteins in dystrophic (dy/dy) mouse muscle shown by lectin binding

Lectin binding sites in skeletal muscle from normal and dystrophic (dy/dy) C57 BL/6J mice were demonstrated by use of histochemistry and electrophoresis combined with electron microscopy. The following lectins were used: Canavalia ensiformis Con A, Triticum vulgaris (WGA), Glycine max (SBA), Griffonia simplicifolia (GS II), Arachis hypogaea (PNA), Pisum sativum (PSA) and Lens culinaris (LCA). After incubation of frozen sections with Con A, WGA, GS II, PSA and LCA a sarcoplasmic staining was observed in both normal and dystrophic muscle. The most consistent light microscopic observations in the dystrophic muscles were a decreased staining intensity of the sarcoplasm after incubation with Con A, WGA, PSA and LCA, but not with GS II, and a strong staining of the interfiber connective tissue. Supernatants, deprived of organelles and membranes, were prepared from normal and dystrophic muscle by high speed centrifugation. Lectin stained Western blots of the supernatant from dystrophic muscle showed two bands (120 and 67 K) with high affinities to avidin. Further this supernatant contained two glycoprotein bands (180 and 140 K) with affinities to Con A and a number of glycoprotein bands with apparent molecular weights below 67 K showing affinities to LCA and PSA. None of these glycoprotein bands could be detected in the supernatant from normal muscle. These changes of the muscle carbohydrate components might be involved in the expression of the dystrophic syndrome This seems to be the first report on changes of soluble glycoproteins in muscular dystrophy.

Lectin binding in skeletal muscle. Evaluation of alkaline phosphatase conjugated avidin staining procedures

Cryostat sections from rat gracilis muscles were incubated with different biotinylated lectins: Con A (Concanavilin A), WGA (Wheat germ agglutinin), SBA (soybean agglutinin), GS I and GS II (Griffonia simplicifolia agglutinin), LCA (Lens culinaris agglutinin), PNA (peanut agglutinin) and PSA (Pisum sativum agglutinin). The sections were subsequently treated with alkaline phosphatase conjugated avidin. The lectin binding sites were visualized after incubation in substrate media containing: (1) 5-bromo-4-chloro indoxyl phosphate and Nitro Blue tetrazolium or copper sulphate; (2) naphthol AS-MX phosphate or naphthol AS-BI phosphate and various types of diazonium salts; (3) alpha-naphthylphosphate and Fast Blue BB; (4) beta-glycerophosphate according to the method of Gomori. The results obtained with the alkaline phosphatase methods were compared with those seen with a streptavidin-horseradish peroxidase procedure. Several chromogen protocols for visualizing alkaline phosphatase activity showed differences in the ability to detect lectin binding sites. A sarcoplasmic reaction was evident for Con A, GS II, WGA, LCA, and PSA after incubation in the indoxyl phosphate medium. Sarcoplasmic reaction for GS II was also noticed after incubation with naphthol AS-MX Fast Blue BB and beta-glycerophosphate. The latter substrate also gave rise to a sarcoplasmic Con A reaction. With the indoxylphosphate tetrazolium salt method some muscle fibres showed a very strong intracellular reaction after incubation with Con A and GS II while the staining intensity was weak in other fibres. The same muscle fibres were stained with PAS. No sarcoplasmic reactions were observed with either naphthol phosphate media or with the diaminobenzidine peroxidase methods. Further, the staining of the muscle fibre periphery, connective tissue, an capillaries was intensified using the indoxyl method. The indoxylphosphate-tetrazolium salt method seems to be suitable for future investigations of lectin binding sites in muscle sections.

Non-specific esterases in partly mineralized bovine enamel

Activity for non-specific esterase was demonstrated in the matrix of developing bovine enamel with alpha-naphthyl acetate and 5-bromoindoxyl acetate as the esterase substrates. By use of high-performance liquid chromatography gel filtration, ion-exchange chromatography, and electrophoresis three esterases were shown to be present in the enamel matrix. The enzymes showed highest activity at pH 6.5-7.5. In sections a strong reaction was observed in the secretory ameloblasts. The esterases may be proteolytic enzymes that participate in the degradation of the matrix proteins.

Carboxylic ester hydrolases in mitochondria from rat skeletal muscle

A mitochondrial pellet, prepared from rat skeletal muscle, contained a number of carboxylic ester hydrolase isoenzymes. The esterases which split alpha-naphthyl acetate were organophosphate sensitive, whereas two out of three indoxyl acetate hydrolysing enzymes were resistant to both organophosphate and organomercury. The activity of the indoxyl acetate esterases was enhanced by the non-ionic detergents Tween-40 and Lubrol. After freezing, thawing and high speed centrifugation most of the alpha-naphthyl acetate splitting enzymes were found in the supernatant, indicating that the enzymes are loosely bound to mitochondrial membranes.

Electrophoretic demonstration of glycoproteins, lipoproteins, and phosphoproteins in human and bovine enamel

Enamel proteins from fully mineralized human molars and from bovine tooth germs were separated by electrophoresis. The gels were stained for detection of glycoproteins, lipoproteins, and phosphoproteins. Glycoproteins were shown by periodic acid-Schiff staining and lectin blotting. In mature human enamel a number of high molecular weight proteins could be demonstrated after ethylenediaminetetra-acetic acid demineralization and subsequent Triton X-100 extraction. These proteins are suggested to be lipoproteins. Phosphoproteins could only be visualized in enamel matrix from the tooth germs.

Non-specific esterases and esterproteases in masticatory muscles from the muscular dystrophic mouse

With the aid of histochemical and electrophoretic techniques activities for esterase and esterprotease were investigated in the digastric and masseter muscles from normal and dystrophic mice. The substrates used were alpha-naphthyl acetate and N-acetyl-L-alanine alpha-naphthyl ester. According to the microscopic observations of the dystrophic muscles the histopathological changes in the masseter muscle were much more pronounced than in the digastric muscle. The connective tissue surrounding the myofibers of the dystrophic masseter contained a large number of cells with pronounced enzyme activity. Among them were mast cells that were strongly stained for esterprotease. The connective tissue of the dystrophic digastricus was much less infiltrated with cellular elements reacting for esterprotease. In zymograms the normal digastricus, the dystrophic masseter and the dystrophic digastricus showed a strong activity for certain isoenzymes that were absent or weakly expressed in the normal masseter.

Chromatographic separation of alkaline phosphatase from dental enamel

Alkaline phosphatase (AP) was prepared from partly mineralized bovine enamel by extraction in phosphate buffer, centrifugation and various chromatographic techniques. Chromatofocusing showed that the enamel enzyme possessed five isoelectric points at the acid pH level ranging from pH 5.7 to pH 4.4. Three enzyme peaks were eluted using low pressure chromatography with a Bio-gel column. With a HPLC gel filtration column the separation of the enamel extract resulted in only one peak with AP activity. The fractions of this peak were used to produce an antibody against bovine AP.

Antikeratin antibodies in routine diagnostic pathology. A comparison of 10 different commercial antikeratins

Ten commercially available antikeratin antisera were tested immunohistochemically on fresh frozen and formalin-fixed paraffin-embedded tissue. Eight of the antisera were in addition tested on protein-immunoblottings. For six of the antisera a good correspondence was found between our immunoblots and data given by the manufacturers. Two monoclonal antisera did not react with keratin proteins. On immunohistochemical testing two of the antibodies showed qualitatively identical staining on both frozen and paraffin sections without background staining. Three of the antibodies reacted weakly or not at all on paraffin sections but gave acceptable staining on frozen sections. Three of the antibodies showed acceptable staining on paraffin sections, but background staining on frozen sections and one antibody gave the reverse staining pattern. For one of the antibodies it was impossible to obtain an acceptable staining due to high non-specific binding of the secondary antibody. None of the antikeratins were true panepithelial tumour markers as all of them failed to detect keratin in at least one of the epithelial tumours. However, a combination of two or three antikeratins (Hybritech AE1 + AE3, Becton Dickinson No 7650, DAKO A622) covered most or all epithelial tumours examined. It is concluded that commercially available antisera show great variability with respect to quality and reactivity indicating that the majority need further purification, characterization and testing on tissues before they are introduced on the commercial market.

Esterase profile of human masseter muscle

The esterase profile of fresh human masseter muscle was investigated by use of histochemistry and electrophoresis. The histochemical methods included reactions for alpha-naphthyl esterase, myofibrillar ATPase, reverse myofibrillar ATPase and succinic dehydrogenase. In frozen sections of the muscle the coloured reaction product for esterases was present both as a diffuse sarcoplasmic coloration and as distinct granules. The intensity of diffuse reaction was used to classify the muscle fibres as strongly, moderately and weakly reacting. The fibres with strong esterase activity belonged to Type I and iiC. iM and Type II A fibres showed a moderate esterase reaction and Type II B fibres had a low activity. The electrophoretic gels stained for esterase activity showed that the human masseter muscle possesses a slow migrating double band with high enzyme activity and a cascade of faster migrating isoenzymes. In isoelectric focused gels the major esterases showed isoelectric points around pH 5.

A comparison between activities for non-specific esterases and esterproteases

Electrophoretic separation of non-specific esterases and esterproteases from kidney, lung, and liver have been carried out in polyacrylamide gels. By use of zone electrophoresis, isoelectric focusing, and 2-dimensional electrophoresis it was found that most of the esterprotease bands had the same localization in the gels as non-specific esterase bands. A number of esterase bands showed no activity towards the esterprotease substrates and a single kidney band possessed esterprotease activity only. Isozymes of the ES-6 and ES-9 zones showed sex dependent esterprotease reactions. In sections esterase activity was located to all parts of the proximal tubule. In male kidneys, esterprotease activity was present in the 2nd segment of the convoluted tubule which is not connected to glomeruli and in the descending part of the proximal tubule. In female kidney only the descending part of the proximal tubule showed esterprotease activity.

Biochemical characterization of alkaline phosphatase from partly mineralized bovine enamel

Alkaline phosphatase (AP) from partly mineralized bovine enamel was studied. The enzyme resembles alkaline phosphatases in other calcifying tissues. The Km was 0.46 mM; the phosphatase was strongly inhibited by 1 mM Levamisol or EDTA and it showed the same sensitivity towards heating as bone alkaline phosphatase. The inactivation caused by phosphate ions was approximately about 30%. In a zymogram, five isozymes of enamel alkaline phosphatase can be recognized. In a SDS-polyacrylamide gel a single band showing enzyme activity was visualized. This enzyme has an apparent molecular weight of 140,000.

Influence of cations on enamel phosphatase activity

ATP and 5-Br-4-Cl-indoxyl phosphate were used as substrates for spectrophotometric measurement of phosphatase activity in partly mineralized bovine enamel. MgCl2, CaCl2, NaCl, and KCl were used as moderators of the enzyme activities. It is concluded that at least two phosphatases, active at alkaline pH, are present in the immature enamel matrix.

Effects of different extraction media on the electrophoretic pattern of proteins from partly mineralized bovine enamel

Five different extraction solutions were used to isolate matrix proteins from immature bovine enamel, to evaluate the effect of this procedure on the pattern obtained after electrophoresis. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the dominating protein fraction in the ethylenediaminetetraacetic acid extract had a molecular weight of 67,000 daltons. The acetic acid and phosphate buffer extracts contained mostly low molecular weight proteins. Isoelectric focusing showed that most of the enamel proteins had isoelectric points below pH 7.0.

Differentiation-dependent expression of keratins in human oral epithelia

The polypeptide composition of epithelial keratins varies with the state of differentiation. The epithelia lining the human oral cavity show regional variations in their histology. In the present study, paired samples of nonkeratinized buccal epithelium and keratinized hard palate epithelium were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and by immunoblots with monoclonal antibodies AE1, AE2, and AE3, and results were correlated with immunofluorescence staining of tissue sections of the same samples. Keratins from hard palate (Mr 67K, 63-65K, 58K, 56.5K, 56K, 50K, 48K) and epidermis (Mr 67K, 63-65K, 58K, 56.5K, 50K) were similar to each other but distinctly different from those of buccal epithelium (major bands of Mr 52K and 59K, minor bands of 50K and 58K). The immunoblot analysis further indicated the similarity of hard palate and epidermal keratins, in contrast to those of buccal epithelium. Each oral tissue expressed keratins of the type I (AE1, acidic) subfamily and type II (AE3, basic) subfamily. In tissue sections, the predominant staining pattern for nonkeratinized buccal epithelium was: AE1, positive in the basal layer; AE2, negative; AE3, positive in all layers. In contrast, the staining pattern for keratinized palatal epithelium was: AE1 and AE2, positive in the suprabasal layers; AE3, positive in all layers. Strong suprabasal AE1 staining in palate may be related to the presence of the 48K keratin. Some buccal samples showed an alternate staining pattern of spotty suprabasal staining with AE1 and AE2 which was correlated with the expression of the 56.5K and 63-67K keratins, as well as filaggrin. These results suggest differentiation-specific expression of the keratins and show immunologically detectable variation in the apparently normal differentiation pattern of nonkeratinized buccal epithelium.

Streptococci and activities of sucrases and alpha-amylases in supragingival dental plaque and saliva in three caries activity groups

Thirty-eight young adults participated in the study. They were divided in a caries-inactive group, a low caries activity group and a moderate to high caries activity group. Total cultivable bacteria, Streptococcus salivarius, and S. mutans in plaque and saliva were quantitated on TSA, MS, and MSB plates, respectively. Sucrase activity was determined by measuring reducing sugars in plaque and saliva after incubation with sucrose. alpha-Amylase activity was determined by Pharmacia Phadebas Amylase test. The data were analyzed with the non-parametric Mann-Whitney U test. The only significant difference was observed for plaque alpha-amylase activity between the caries-inactive group and the moderate-high caries activity group (P less than 0.05). The lack of differences concerning the other variables is discussed mainly on the basis of the multifactorial character of dental caries and the possible insufficiency of the applied methods.

Keratin proteins in human oral mucosa

We have examined the keratin proteins in normal human oral mucosa from 6 different regions including hard palate, buccal mucosa, tongue, gingiva and floor of the mouth. Urea-dithiothreitol extracts of EDTA separated epithelia were analysed by SDS-PAGE and immunoblotting. Eight samples from each region were investigated and showed very little individual variation in the keratin profile on Coomasie Blue-stained gels. The keratinizing hard palate and gingiva expressed identical patterns and resembled the pattern of epidermis from the flank region. The normally non-keratinizing buccal mucosa and the mucosa of the floor of the mouth expressed polypeptides distinctly different from those of the keratinizing epithelia and lacked the high molecular weight keratins. The dorsal surface of the tongue and the commissure region showed a pattern intermediate between keratinizing and non-keratinizing epithelia. The greater sensitivity of the immunoblotting technique revealed that the non-keratinizing epithelia synthesized one of the high molecular polypeptides and that the tongue produced all the bands found in keratinizing epithelia, but in very small quantities. There are, thus, distinct differences in the keratin expression of oral epithelia which are related to the pattern of keratinization assessed histologically.

Studies on the actions of glutaraldehyde, formaldehyde, and mixtures of glutaraldehyde and formaldehyde on tissue proteins

The effects of aldehyde fixation on tissue proteins was studied using SDS-polyacrylamide gel electrophoresis. Fixation with low concentrations of formaldehyde or glutaraldehyde had only a slight effect on the protein banding pattern. On the other hand, most of the original protein bands were absent after a short treatment with mixtures of formaldehyde and glutaraldehyde. Spectral absorption measurements showed a stronger absorption at both gamma = 280 nm and gamma = 235 nm with the glutaraldehyde-formaldehyde mixture than with glutaraldehyde alone.

Immunoblotting demonstration of antibodies to the organic matrix of developing bovine enamel

Antiserum was raised against an acetic acid extract of partly mineralized bovine enamel. By use of immunoblotting it was shown that rabbit antibodies react with both high and low molecular weight proteins. Most but not all of the enamel proteins isolated by different extraction solutions were antigenic identical. The blotting time was found to be important when immunoblotting of enamel proteins is carried out.

Biochemical and histochemical studies on alkaline phosphatase in normal and dystrophic muscle

In muscles from dystrophic mice the activity of alkaline phosphatase is 50-75% higher than in their control littermates. In the dystrophic animals all muscle fibres show strong enzyme activity. It is suggested that during dystrophy amounts of an already existing muscle alkaline phosphatase are produced rather than that a synthesis of a new isoenzyme should be initiated.