Secondary Injuries After Pediatric Anterior Cruciate Ligament Reconstruction: A Systematic Review With Quantitative Analysis.

BACKGROUND: In the skeletally mature anterior cruciate ligament (ACL) reconstruction population, patients aged <25 years are at significantly increased risk of graft failure and injury to the contralateral ACL. Skeletal immaturity often affects graft selection and reconstruction technique. PURPOSE: To examine the incidence of ipsilateral graft failure and contralateral ACL injury in the skeletally immature patient population. STUDY DESIGN: Systematic review and meta-analysis. METHODS: Using the PRISMA (Preferred Reporting Items for Systematic Meta-Analyses) guidelines, we reviewed all literature that involved ACL reconstruction performed on skeletally immature patients between May 1976 and May 2019. Patient demographics, surgical technique, and the prevalence of ipsilateral graft failure or subsequent contralateral ACL injury were recorded. Ipsilateral, contralateral, and secondary ACL injuries were then compared between sexes via chi-square tests. RESULTS: A total of 24 articles (1254 children; 1258 knees) met inclusion criteria for analysis. Ipsilateral graft failures occurred in 105 of 1258 patients (8.3%), and there were no statistically significant sex differences in the prevalence of graft failures (female, 9.7%; male patients, 7.1%; P = .14). The prevalence of contralateral ACL injury was significantly greater in female (29/129; 22.5%) than male (18/206; 8.7%; P = .0004) patients in the 9 studies that reported contralateral injury. Skeletally immature female patients were at significantly increased risk of contralateral ACL injury (odds ratio = 3.0; P = .0006) when compared with their male counterparts. CONCLUSION: In the literature to date, 1 in 3 female skeletally immature patients experienced an ipsilateral graft failure or contralateral ACL injury. Regardless of sex, the 24% prevalence of secondary injury after pediatric ACL reconstruction is almost identical to previously published secondary injury rates in skeletally mature patients <25 years old. As such, skeletal maturity alone does not seem to be a determinant of secondary injury; however, there is a clear need to improve postoperative rehabilitation, activity progression, and return-to-play testing to allow a safe return to sports that protects the long-term health of the reconstructed and contralateral limbs, especially for female patients.

Evaluation of a Workplace Exercise Program for Control of Shoulder Disorders in Overhead Assembly Work.

OBJECTIVE: The aim of this study was to assess effects of exercise on shoulder musculoskeletal symptoms among employees with overhead assembly work exposures. METHODS: A voluntary workplace shoulder exercise program was offered to employees in two automotive assembly departments, while two similar departments served as controls. N = 76 total workers participated. Shoulder Rating Questionnaire (SRQ) and Discomfort of the Arm Shoulder and Hand (DASH) symptoms were queried monthly for 7 baseline months, followed by 6 months that included exercise. RESULTS: SRQ scores were higher for exercisers than among controls in the 6 exercising months, but not in the baseline months. Although the group x month interaction was significant (P < 0.05), the temporal trend was inconsistent. CONCLUSIONS: Exercise may have temporarily lessened decline in SRQ. It is not clear whether shorter term differences were clinically meaningful or predictive of longer term disability prevention.

Cloning, sequencing, purification, and crystal structure of Grenache (Vitis vinifera) polyphenol oxidase.

The full-length cDNA sequence (P93622_VITVI) of polyphenol oxidase (PPO) cDNA from grape Vitis vinifera L., cv Grenache, was found to encode a translated protein of 607 amino acids with an expected molecular weight of ca. 67 kDa and a predicted pI of 6.83. The translated amino acid sequence was 99%, identical to that of a white grape berry PPO (1) (5 out of 607 amino acid potential sequence differences). The protein was purified from Grenache grape berries by using traditional methods, and it was crystallized with ammonium acetate by the hanging-drop vapor diffusion method. The crystals were orthorhombic, space group C222(1). The structure was obtained at 2.2 A resolution using synchrotron radiation using the 39 kDa isozyme of sweet potato PPO (PDB code: 1BT1 ) as a phase donor. The basic symmetry of the cell parameters (a, b, and c and alpha, beta, and gamma) as well as in the number of asymmetric units in the unit cell of the crystals of PPO, differed between the two proteins. The structures of the two enzymes are quite similar in overall fold, the location of the helix bundles at the core, and the active site in which three histidines bind each of the two catalytic copper ions, and one of the histidines is engaged in a thioether linkage with a cysteine residue. The possibility that the formation of the Cys-His thioether linkage constitutes the activation step is proposed. No evidence of phosphorylation or glycoslyation was found in the electron density map. The mass of the crystallized protein appears to be only 38.4 kDa, and the processing that occurs in the grape berry that leads to this smaller size is discussed.

Broccoli processing wastes as a source of peroxidase.

A peroxidase isozyme (BP) was purified to homogeneity from broccoli stems ( Brassica oleraceae var. maraton) discarded from industrial processing wastes. BP specific activity was 1216 ABTS [2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid)] units/mg, representing 466-fold that of crude extract. BP is a monomeric glycoprotein containing 16% carbohydrates, with a molecular mass of 49 kDa and an isoelectric point close to 4.2. From kinetic data it showed a two-substrate ping-pong mechanism, and the catalytic efficiency measured as the rate-limiting step of free BP regeneration was 3.4 x 10(6) M(-1) s(-1). The ABTS K m value was 0.2 mM, which was about 20 times lower than that reported for acidic commercial horseradish peroxidase (HRP). Assessment of BP secondary structure showed 30% helical character, similar to HRP and cytochrome c peroxidase. BP lost only 25% activity after 10 min of heating at 55 degrees C and pH 6; it was stable in the pH range from 4 to 9 and showed an optimum pH of 4.6 using ABTS as substrate. BP was active on substrates normally involved in lignin biosynthesis, such as caffeic and ferulic acids, and also displayed good catechol oxidation activity in the presence of hydrogen peroxide. Reverse micellar extraction was successfully used as potential large-scale prepurification of broccoli peroxidase, achieving a purification factor of 7, with 60% activity yield. Stems from the broccoli processing industry have a high potential as an alternative for peroxidase purification.

Reactivation of broccoli peroxidases: structural changes of partially denatured isoenzymes.

UNLABELLED: Structural changes involved in the reactivation of peroxidases (PODs) from broccoli and horseradish (HRP) following heat denaturation were investigated by using circular dichroism and absorption spectroscopy. Cooling heat-treated enzymes resulted in rapid refolding of the secondary structure into an inactive structural species, similar in conformation to the native enzyme. Reassociation of heme to the refolded peroxidase, as well as molecular rearrangement of the structure around the heme, occurs during incubation at approximately 25 degrees C and results in the return of biological activity. The secondary structure of neutral broccoli POD (N) is relatively heat labile, resulting in a rapid loss of activity, but the level of reactivation is high because the structure at the heme pocket is relatively stable. Acidic broccoli POD and HRP are more heat stable than N, but have a low degree of reactivation. Loss of activity is due primarily to alteration of the structure at the heme pocket. Effects of bovine serum albumin and pH on reactivation of PODs are also discussed. KEYWORDS: Peroxidase; reactivation; horseradish; broccoli; circular dichroism; absorption spectroscopy.

Are molecular weights of proteins determined by superose 12 column chromatography correct?

Our research on several proteins indicates that accurate molecular weights cannot be determined by Superose 12 column chromatography. In support of this statement, we present data on molecular weights of purified red kidney bean alpha-amylase inhibitor (RKB alphaAI) and white kidney bean alpha-amylase inhibitor (WKB alphaAI) to document this problem. The molecular weight of purified RKB alphaAI determined by Sephadex G-100 gel filtration, polyacrylamide gel electrophoresis, Superose 12 gel filtration and cDNA were 49.0, 51.0, 22.9, and 49.805 kDa (not glycosylated), respectively. The molecular weights of WKB alphaAI by several methods were as follows: Sephadex G-100 gel filtration, 51.0 kDa; Superose 12 gel filtration in 0.2 M NaCl buffer, 23.1 kDa; polyacrylamide gel electrophoresis (PAGE), 51.0 kDa; sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), 45.0 kDa; multiangle laser light scattering (MALLS), 49.940 kDa; laser-assisted time-of-flight mass spectrometry (LATOFMS), 56.714 kDa; and cDNA sequence (with 12.2% carbohydrate), 55.9 kDa. The data indicate there is ionic interaction between proteins and the matrix of Superose 12 in low ionic strength buffers and hydrophobic interaction at higher ionic strength buffers. Researchers should be cautious when using Superose 12 columns for molecular weight determinations.

Unusual structural characteristics and complete amino acid sequence of a protease inhibitor from Phaseolus acutifolius seeds.

Two isoforms of a protease inhibitor were isolated by ion-exchange chromatography of tepary bean (Phaseolus acutifolius G.) seed proteins. The main isoform was used to determine the amino acid sequence of the protein. It is an 80 amino acid residue protein with a molecular mass of 8765 Da, showing sequence homology with the Bowman-Birk family of protease inhibitors. Several regions with amino acid microheterogeneity were found, corroborating the possible presence of isoforms. Mass spectrometry analysis was carried out to confirm isoforms. The presence of dimer and trimer forms of the inhibitor was shown through electrophoresis and mass spectrometry. Another unusual characteristic for this inhibitor was its ability to bind metals. The presence of four sequential histidines at the N-terminal end of the protein could account for this binding. Mass spectrometry and atomic absorption spectroscopy support the presence of calcium in the native inhibitor.

Isolation and thermal characterization of an acidic isoperoxidase from turnip roots.

An acidic peroxidase (pI approximately 2.5) was purified from turnip roots (TAP), and its thermal properties were evaluated. TAP is a monomeric protein having a molecular weight (MW) of 49 kDa and a carbohydrate content accounting for 18% of the MW. The yield of pure TAP was relatively high ( approximately 2 mg/kg of fresh roots), with a specific activity of 1810 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) units/mg at pH 6. The activity increased 4-fold at the optimum pH (4.0) to 7250 ABTS units/mg, higher than that of most peroxidases. TAP was heat stable; heat treatment of 25 min at 60 degrees C resulted in 90% initial activity retention, whereas an activity of 20% was retained after 25 min of heating at 80 degrees C. TAP regained 85% of its original activity within 90 min of incubation at 25 degrees C, following heat treatment at 70 degrees C for 25 min. Thermal inactivation caused noticeable changes in the heme environment as evaluated by circular dichroism and visible spectrophotometry. TAP was rapidly denatured by heating in the presence of 1.0 mM ethylene glycol bis(beta-aminoethyl ether) N,N,N',N'-tetraacetic acid, but the Soret band and activity were fully recovered by adding an excess of Ca(2+). This is further evidence that Ca(2+) plays an important role in the stability of TAP. The high specific activity of TAP, together with its relatively high thermal stability, has high potential for applications in which a thermally stable enzyme is required.

Crystallochemical characterization of calcium oxalate crystals isolated from seed coats of Phaseolus vulgaris and leaves of Vitis vinifera.

Calcium oxalate crystals are a major biomineralization product in higher plants. Their biological function and use are not well understood. In this work, we focus on the isolation and crystallochemical characterization of calcium oxalate crystals from seed coats of Phaseolus vulgaris (prisms) and leaves of Vitis vinifera (raphides and druses) using ultrastructural methods. A proposal based on crystal growth theory was used for explaining the existence of different morphologies shown by these crystals grown inside specialized cells in plants.

Monosaccharide composition and properties of a deglycosylated turnip peroxidase isozyme.

A neutral peroxidase isozyme (TP) purified from turnip (Brassica napus L. var. purple top white globe) was partially deglycosylated, using chemical and enzymatic treatment. A 32% carbohydrate removal was achieved by exposing TP to a mixture of PNGase F, O-glycosidase, NANase, GALase III and HEXase I, while m-periodate treatment removed about 88% of TP carbohydrate moiety. The glycoprotein fraction of the TP contained a relatively high mannose and fucose content (37 and 31%, w/w, respectively), 16% (w/w) galactose, and 15% (w/w) GlcNAc. Thus, the carbohydrate moiety was classified as a hybrid type. Partially deglycosylated TP had reduced activity (by 50-85%), was more susceptible to proteolysis, and showed a slight decrease in thermostability compared to the native enzyme. Circular dichroism studies strongly suggested that although the carbohydrate moiety of TP did not influence the conformation of the polypeptide backbone, its presence considerably enhanced protein conformational stability toward heat. Removal of oligosaccharide chains from TP caused a decrease in K(m) and V(max) for hydrogen peroxide. Native and chemically deglycosylated TP were similarly immunodetected by rabbit polyclonal antibodies raised against TP. The results suggest that the carbohydrate moiety of TP is important for peroxidase activity and stability.

Protein structures of common bean (Phaseolus vulgaris) alpha-amylase inhibitors.

Two nucleotide sequences for genes that encode alpha-amylase inhibitor 4 (alphaAI-4) from white kidney bean (WKB) cv. 858, designated gene alphaAI-4 (Accession No. ), and alpha-amylase inhibitor 5 (alphaAI-5) from black bean (BB), designated gene alphaAI-5 (Accession No. ), were determined. Genes alphaAI-4 and alphaAI-5 encode 244 amino acid prepro-alphaAI-4 and prepro-alphaAI-5 polypeptides that are 93 and 95% identical with alpha-amylase inhibitor l (alphaAI-l; Hoffman, L. M.; Ma, Y.; Barker, R. F. Nucleic Acids Res. 1982, 10, 7819-7828), 40 and 43% identical with red kidney bean lectin, and 52 and 55% identical with arcelin l of wild-type bean. The high degree of sequence similarity indicates the evolutionary relationship among these genes. PCR analysis of genomic DNA purified from six genotypes of Phaseolus vulgaris showed very similar band patterns in 2% agarose gel, another indication of the conserved size homology among these genes. Proteolytic processing sites were located between Asn77 and Ser78 for pro-alphaAI-4 and pro-alphaAI-5. A bend next to Asn77 in three-dimensional model structures of alphaAI-4 and alphaAI-5 proinhibitors indicates that the proteolytic cleavage is necessary to remove the conformational constraint for activation to the mature protein. Mature WKB alphaAI-4 was composed of four subunits (2alpha2beta) and had a molecular weight of 50000 determined by multiangle laser light scattering and 56714 determined by laser-assisted time-of-flight mass spectrometry.