Maternal heterozygosity and progeny fitness association in an inbred Scots pine population.

Associations between heterozygosity and fitness traits have typically been investigated in populations characterized by low levels of inbreeding. We investigated the associations between standardized multilocus heterozygosity (stMLH) in mother trees (obtained from12 nuclear microsatellite markers) and five fitness traits measured in progenies from an inbred Scots pine population. The traits studied were proportion of sound seed, mean seed weight, germination rate, mean family height of one-year old seedlings under greenhouse conditions (GH) and mean family height of three-year old seedlings under field conditions (FH). The relatively high average inbreeding coefficient (F) in the population under study corresponds to a mixture of trees with different levels of co-ancestry, potentially resulting from a recent bottleneck. We used both frequentist and Bayesian methods of polynomial regression to investigate the presence of linear and non-linear relations between stMLH and each of the fitness traits. No significant associations were found for any of the traits except for GH, which displayed negative linear effect with stMLH. Negative HFC for GH could potentially be explained by the effect of heterosis caused by mating of two inbred mother trees (Lippman and Zamir 2006), or outbreeding depression at the most heterozygote trees and its negative impact on the fitness of the progeny, while their simultaneous action is also possible (Lynch. 1991). However,since this effect wasn't detected for FH, we cannot either rule out that the greenhouse conditions introduce artificial effects that disappear under more realistic field conditions.

Simultaneous estimation of multiple quantitative trait loci and growth curve parameters through hierarchical Bayesian modeling.

A novel hierarchical quantitative trait locus (QTL) mapping method using a polynomial growth function and a multiple-QTL model (with no dependence in time) in a multitrait framework is presented. The method considers a population-based sample where individuals have been phenotyped (over time) with respect to some dynamic trait and genotyped at a given set of loci. A specific feature of the proposed approach is that, instead of an average functional curve, each individual has its own functional curve. Moreover, each QTL can modify the dynamic characteristics of the trait value of an individual through its influence on one or more growth curve parameters. Apparent advantages of the approach include: (1) assumption of time-independent QTL and environmental effects, (2) alleviating the necessity for an autoregressive covariance structure for residuals and (3) the flexibility to use variable selection methods. As a by-product of the method, heritabilities and genetic correlations can also be estimated for individual growth curve parameters, which are considered as latent traits. For selecting trait-associated loci in the model, we use a modified version of the well-known Bayesian adaptive shrinkage technique. We illustrate our approach by analysing a sub sample of 500 individuals from the simulated QTLMAS 2009 data set, as well as simulation replicates and a real Scots pine (Pinus sylvestris) data set, using temporal measurements of height as dynamic trait of interest.

Dose-related cellular effects of platelet-derived growth factor-BB differ in various types of rabbit tendons in vitro.

Cellular responsiveness to growth factors that can affect tendon healing may be site-specific. We have compared the dose-response effects of platelet-derived growth factor-BB (PDGF-BB) on proteoglycan, collagen, noncollagen protein and DNA synthesis between intrasynovial intermediate and proximal segments of deep flexor tendons, and extrasynovial peroneal tendons of rabbits during short-term cultures. PDGF-BB stimulated matrix and DNA synthesis of the three types of tendon segments in a dose-dependent manner in the range from 0.1 to 100 ng/mL. PDGF-BB stimulated collagen synthesis and noncollagen protein synthesis (calculated from LogED50) in proximal intrasynovial tendon segments more than in extrasynovial peroneal tendon segments, and DNA synthesis less in proximal than in intermediate intrasynovial tendons. However, the estimated maximal stimulations (Emax) by PDGF-BB were similar in the three types of tendon segments. These findings show that PDGF-BB stimulates DNA and matrix synthesis differently in various types and regions of tendons during short term explant culture and suggests that there may be differences in cellular responsiveness during tendon healing.

The effects of reduced oxygen tension on cell proliferation and matrix synthesis in synovium and tendon explants from the rabbit carpal tunnel: an experimental study in vitro.

Local ischemia may play an important role in the development of tendon degeneration as well as entrapment neuropathies. In order to investigate the cellular effects of hypoxia on tendon and synovial tissue from the carpal canal, dose response effects of oxygen on cell proliferation and synthesis of matrix components were examined in segments of synovial and flexor digitorum profundus tendon from the carpal tunnel of rabbits during short term culture. Explants were incubated in airtight containers flushed with either 0%, 1%, 3%, 20% O2 plus 2% CO2 and N2 to balance and labeled with either 3H-thymidine or 3H-proline and 35S-sulfate. Cell proliferation was significantly inhibited by hypoxia in synovium but not in tendon (P = 0.03). In parallel, the synthesis of non-collagenous proteins was significantly reduced in synovium but not in tendon (P = 0.006). In both tissues hypoxia significantly inhibited collagen synthesis. On the other hand, hypoxia had no significant effect on the synthesis of new proteoglycans as determined by 35S-sulfate incorporation. Hypoxia can inhibit cell proliferation and alter synthesis of matrix components in synovial tissue, but may only have minor effects on non-collagen protein synthesis in tendon explants from the carpal canal of rabbit forepaws.

Hyaluronic acid modulates cell proliferation unequally in intrasynovial and extrasynovial rabbit tendons in vitro.

As tendons differ in biochemical composition and cellular capacities, we have compared dose response effects of hyaluronic acid on cell proliferation and synthesis of matrix components in intermediate and proximal segments of intrasynovial deep flexor tendons and extrasynovial peroneus rabbit tendons in vitro. Compared with matched control tendons, hyaluronic acid inhibited cell proliferation in intermediate and proximal intrasynovial flexor tendon segments at the concentrations of 0.1-2.0 mg/ml and 0.5-2.0 mg/ml respectively, but in extrasynovial tendon segments only at the concentration of 0.5 mg/ml. Hyaluronic acid did not affect synthesis of proteoglycan, collagen and non-collagen protein in either type of tendon. These results show that hyaluronic acid modulates cell proliferation unequally in intra- and extrasynovial tendons without affecting the synthesis of matrix components in the two types of tendons, indicating differential hyaluronic acid sensitivity and a possible mechanism of action.

Rehabilitation after subcutaneous transposition of the ulnar nerve: immediate versus delayed mobilization.

We studied 36 patients who had clinical signs and symptoms consistent with cubital tunnel syndrome and in whom nonoperative management failed. These patients underwent anterior subcutaneous transposition of the ulnar nerve followed by either immediate (20 patients) or delayed (16 patients) mobilization. All patients were evaluated with an outcomes assessment questionnaire, and 35 of the 36 were given repeat physical examinations. After surgery, there were no significant differences between the two groups in pain relief, weakness, or patient satisfaction (71% of the immediate mobilization group and 74% of the delayed group) were satisfied. Secondary quantitative outcomes such as grip strength, lateral pinch, or two-point discrimination were also not significantly different between the groups. Both groups had a statistically significant improvement in first dorsal interosseous and adductor pollicis muscle strength. In the immediate mobilization group, however, patients returned to work and resumed activities of daily living earlier (median 1 month) than patients in the delayed mobilization group (median 2.75 months). Therefore, we conclude that anterior subcutaneous transposition provides a high degree of satisfaction and relief of symptoms regardless of when mobilization is initiated. However, immediately mobilizing the patient significantly influenced how early the patient returned to work and resumed activities of daily living.

Tendon repair--cellular activities in rabbit deep flexor tendons and surrounding synovial sheaths and the effects of hyaluronan: an experimental study in vivo and in vitro.

One deep flexor tendon and its surrounding sheath of each hindpaw of 48 rabbits were transected and repaired in order to investigate the abilities of rabbit flexor tendons and synovial sheaths to synthesize DNA and matrix components during healing and to study the effects of hyaluronan (HA). After repair, HA or saline was injected between the tendon and the sheath. Short-term culture and labeling in vitro were used up to 6 weeks after surgery to determine synthesis of DNA, proteoglycan, collagen, and noncollagen protein. Within tendon repair sites, the rate of cell proliferation increased and reached a maximum 5 days after surgery; within repaired synovial sheaths, the rate immediately decreased. In the healing tendons, the rate of collagen synthesis decreased and the rate of noncollagen protein synthesis remained unchanged. The opposite results were found within the healing synovial sheaths. HA did not affect the rate of cell proliferation or matrix synthesis in healing tendons or surrounding sheaths. These results show that cellular activities differ between tendons and synovial sheaths during healing and that those activities may not be affected by HA.

Similar effects of recombinant human insulin-like growth factor-I and II on cellular activities in flexor tendons of young rabbits: experimental studies in vitro.

To improve the understanding of factors with the potential of affecting the healing of flexor tendons, this study compared the cellular effects of recombinant human insulin-like growth factor-II with those of recombinant human insulin-like growth factor-I in matched pairs of deep flexor tendons of young rabbits. Dose-response effects on the synthesis of DNA and matrix proteins of either factor alone or in combination were investigated in short-term culture, and effects on synthesis and turnover of matrix components were compared in long-term culture. Both factors stimulated proteoglycan, collagen, noncollagen protein, and DNA synthesis in a dose-dependent manner in the range of 10-500 ng/ml. Insulin-like growth factor-I increased proteoglycan synthesis to as much as six times that of controls but was less potent than insulin-like growth factor-II. Both factors stimulated increased cell proliferation by as much as five times compared with control values, but insulin-like growth factor-I was more potent than insulin-like growth factor-II. The two factors in combination did not enhance the synthesis of matrix proteins and DNA as compared with either factor alone. Insulin-like growth factor-I counteracted the decrease in collagen synthesis and stimulated protein synthesis to a higher degree than insulin-like growth factor-II in long-term culture. Both factors had similar effects on matrix turnover, with estimated half times (t1/2) for elimination of newly labeled proteoglycans and proteins of 11 and 8 days, respectively. Insulin-like growth factor-II is capable of stimulating cell proliferation and matrix metabolism in tendon explants of young rabbits at levels similar to those of insulin-like growth factor-I; in combination, the two growth factors are unable to augment the stimulatory effects of either of the factors alone.

Biomechanical effects of operative nerve mobilization and transposition in a canine ulnar nerve model.

The purpose of this study was to evaluate the effects that operative mobilization and transposition of the ulnar nerve have on both neural excursion and mechanical properties. Twelve dogs underwent ulnar nerve transposition and postoperative casting. Four animals were killed at 3 weeks and four animals were killed at 6 weeks. Four animals had their casts removed at 3 weeks, were allowed to ambulate, and were killed at 6 weeks. Operated and contralateral control nerves were compared. Neural excursion was measured near the elbow and 12 cm proximally. The nerves were harvested and their mechanical properties determined. Repeated measures analysis of variance revealed significant differences in longitudinal excursion between control and experimental groups at both sites. Ultimate strain, ultimate strength, and modulus were significantly reduced in the experimental groups. No differences were seen in cross-sectional area or stiffness between control and experimental groups. Analysis revealed no independent effect of the rehabilitation method. Results of this study indicate that significant changes in neural excursion, ultimate strain, ultimate strength, and modulus occur following ulnar nerve mobilization and transposition and that these changes persist throughout the early postoperative period.

Sensory function after median nerve decompression in carpal tunnel syndrome. Preoperative vs postoperative findings.

The sensory recovery was monitored for up to 1 year after decompression of the median nerve in 69 patients with carpal tunnel syndrome. Special attention was paid to the rate of recovery, the importance of constant or intermittent numbness or paraesthesiae preoperatively and the influence of gender. Most patients with numbness/paraesthesiae and those with abnormal two-point discrimination recovered within 10 days. Perception of touch and vibration recovered within 3 weeks in most patients but those with abnormal nerve conduction/sensory amplitude recovered slowly during follow-up. After 1 year patients with intermittent preoperative symptoms were significantly more likely to achieve normal nerve conduction and perception of touch. Women were more likely to achieve normal nerve conduction and perception of touch. A comparison of recovery between matched men and women with identical preoperative status showed no significant difference. The results indicate the importance of early treatment of carpal tunnel syndrome.

Division of flexor tendons causes progressive degradation of tendon matrix in rabbits.

Deep flexor tendons of 30 rabbits were divided at the ankle level. The effects of unloading on the synthesis and content of matrix components, the synthesis of DNA, and dry weight were investigated. The ability of the tendons to synthesize collagen during short-term culture and the contents of matrix components decreased inversely to the time of unloading. 12 weeks following division, the fibrocartilagnious segments had lost 2/5 of their dry weight, 2/3 of proteoglycan and 1/3 of collagen and non-collagen protein content. Less pronounced losses were observed in the non-fibrocartilaginous segments. A transient increase in cell proliferation in both types of segments was found. These findings indicate that divided flexor tendons undergo a progressive degradation, degradation, which may have implications for delayed suture of deep flexor tendon injuries.

Matrix synthesis and cell proliferation in repaired flexor tendons within e-PTFE reconstructed flexor tendon sheaths.

Expanded polytetrafluoroethylene (e-PTFE) may be used as a barrier to reduce formation of restrictive adhesions following tendon surgery within the flexor tendon sheath region. In order to assess its effects on the cellular activity of healing tendons, synthesis and contents of matrix components and synthesis of DNA were compared in divided and sutured flexor tendons that either had been covered with e-PTFE membranes or with sham-operated tendon sheaths in 30 rabbits. At intervals of up to 12 weeks segments of the tendon repair sites were harvested, placed in wells and labelled with 35S-sulphate, 3H-proline and 3H-thymidine during short-term culture in vitro. Adverse tissue reactions and tendon disruptions were not observed at harvest. At each time interval synthesis of matrix components and DNA and contents of protein and collagen in the repaired tendon segments were similar in the two groups. Measured over all intervals, synthesis of non-collagen protein and contents of protein and collagen were lower in the e-PTFE groups. These results show that reconstruction of flexor tendon sheaths with e-PTFE membranes may not significantly impair cell proliferation but to some extent may reduce protein synthesis of healing tendons.

Effects of hyaluronan on cell proliferation and collagen synthesis: a study of rabbit flexor tendons in vitro.

Hyaluronan (HA), a high-molecular-weight polysaccharide, has been suggested to play a possible role during the early stages of healing of a variety of connective tissues and when topically applied to decrease the formation of adhesions following tendon surgery. As the mechanisms of HA actions are still being discussed, this study was designed to assess the effects of HA on cell proliferation and synthesis of matrix components of deep flexor tendons in a well-defined culture system. Cell proliferation, measured as the radioactive 3H-thymidine uptake by cultured segments of rabbit flexor tendons, was inhibited by the addition of HA to the culture medium. HA of molecular weight 0.5 x 10(6) inhibited the uptake significantly at concentrations within the range of 0.1-2.0 mg/mL, HA of molecular weight 1.6 x 10(6) at 0.5-2.0 mg/mL, and HA of molecular weight 3.6 x 10(6) at 1.0-2.0 mg/mL, as compared to matched control groups. At the concentration of 2 mg/mL, HA of the molecular weights of 0.5, 0.8, 1.6, and 3.6 x 10(6) equally inhibited cell proliferation. No effect on synthesis of matrix components, measured as the radioactive incorporation of 35S-sulfate, 3H-hydroxyproline, and 3H-proline by cultured segments of rabbit flexor tendons, was observed. These findings show that exogenously applied HA may act as a modulator of flexor tendon fibroblast proliferation, indicating a possible mechanism for antiadhesive effects following administration after flexor tendon surgery.

Exposure to air during surgery inhibits cellular activity in flexor tendons.

In order to investigate the cellular effects of exposure to air during surgery and to compare the effects of simultaneous irrigation with physiological saline, the deep flexor tendons of both forepaws of 12 rabbits were surgically exposed. In one experiment, the extent of surgical exposure and, in a second experiment, the time of exposure was evaluated. Treated segments of the flexor tendons were collected and labelled in vitro for determination of the ability to synthesize DNA, proteoglycan, collagen and non-collagen protein. With increasing surgical exposure in vivo, an increasing rate of cellular proliferation was observed in segments of the exposed deep flexor tendons examined in vitro. Synthesis of matrix components and the rate of cellular proliferation were reduced by 50% after 40 to 100 minutes of exposure to air and by nearly 100% after 120 minutes of exposure. In contrast, irrigated tendons retained their cellular capacity to proliferate.

Cellular activity in e-PTFE reconstructed pulleys and adjacent regions of deep flexor tendons. An experimental biochemical study in rabbits.

The biological adaptation and integration of flexor tendon pulleys reconstructed with expanded polytetrafluorethylene (e-PTFE) were investigated 3 months after operation. E-PTFE pulleys showed no signs of failure, adverse tissue reactions or detrimental effects on the surface of underlying tendons. Cells in pulleys reconstructed with e-PTFE synthesized proteoglycan, collagen and non-collagen protein at a higher rate, and DNA at a lower rate, than cells in sham operated pulleys. Cells in pulleys reconstructed with e-PTFE synthesized proteoglycan at a lower rate, and protein at a higher rate, than cells in e-PTFE strips placed subcutaneously. Flexor tendon segments underlying reconstructed or sham operated pulleys synthesized matrix components and DNA at comparable rates.

Differential effects of insulin-like growth factor-I on matrix and DNA synthesis in various regions and types of rabbit tendons.

Tendon healing and integration of tendon grafts may be site or donor specific. To determine if differences exist in sensitivity to growth factors that have the potential to influence tendon repair, we compared the effects of recombinant human insulin-like growth factor-I on various types of tendon segments. The dose response effects on proteoglycan, collagen, noncollagen protein, and DNA synthesis were investigated in short-term explant cultures of intrasynovial intermediate and proximal segments of deep flexor tendons extrasynovial segments of deep flexor tendons, and Achilles tendons of rabbits. The four different types of tendon segments cultured in media without recombinant human insulin-like growth factor-I synthesized similar amounts of each of the matrix components. Intrasynovial proximal segments synthesized 15 times less DNA than other tendon segments. Recombinant human insulin-like growth factor-I stimulated matrix and DNA synthesis of all tendon segments in a dose-dependent manner in intervals from 10 to 1,000 ng/ml. The potency (LogED50) of the stimulation did not differ between the segments. The estimated maximal stimulation (E(max)) of proteoglycan synthesis by recombinant human insulin-like growth factor-I was higher, and of collagen and noncollagen protein synthesis was lower, in intrasynovial proximal segments as compared with that of the other types of segments. In contrast, the estimated maximal stimulation of DNA synthesis by recombinant human insulin-like growth factor-I was 6-fold higher than controls in all types of tendons. These findings demonstrate differences in mitotic capacity between anatomical regions of tendons during culture without recombinant human insulin-like growth factor-I and in matrix synthesis after stimulation with it.

Autogenous intrasynovial and extrasynovial tendon grafts: an experimental study of pro alpha 1(I) collagen mRNA expression in dogs.

On the basis of recent evidence that the healing processes of tendon grafts are donor-tissue specific, in situ hybridization, using a 372 bp cDNA fragment complementary to a portion of pro alpha 1(I) collagen mRNA, was utilized to compare the cellular responses to transplantation exhibited by autogenous intrasynovial and extrasynovial flexor tendon grafts. Intrasynovial and extrasynovial tendons from the hindpaw were transferred to synovial sheaths in the forepaw of 12 mongrel dogs (24 tendons) and treated with immediate controlled passive motion. The tendon grafts were harvested at 2, 4, and 6 weeks, and each was divided into a proximal, central (8 mm), and distal portion. Sections from the central portion were embedded in paraffin and subjected to in situ hybridization, autoradiography, and staining; levels of procollagen mRNA then were assessed by microscopic examination. The two types of tendon grafts exhibited different levels of pro alpha 1(I) collagen mRNA expression at all three time points. Intrasynovial tendon grafts displayed no areas of increased type-I procollagen mRNA at 2, 4, and 6 weeks. The extrasynovial tendon grafts displayed increased surface levels of type-I procollagen mRNA at 2 and 4 weeks; the levels decreased to background levels by 6 weeks. The high levels of procollagen mRNA exhibited by the extrasynovial grafts suggest increased collagen synthetic activity, indicative of a cellular response to injury, whereas the preservation of low levels of expression in the intrasynovial grafts may signify a less inflammatory cellular response.

Autogenous flexor tendon grafts: fibroblast activity and matrix remodeling in dogs.

To investigate rates of cellular proliferation and matrix turnover in autogenous flexor tendon grafts, hindlimb intrasynovial (flexor digitorum profundus) and extrasynovial (peroneus longus) tendons were placed within the synovial sheaths of the medial and lateral forepaw digits of 18 dogs and treated with controlled early passive motion. After the dogs had been killed, short-term culture and labeling in vitro were utilized to determine rates of DNA, proteoglycan, collagen, and noncollagen protein synthesis. Schiff base covalent collagen crosslink concentrations and total collagen and protein content also were evaluated at intervals through 6 weeks. Tendon grafts of extrasynovial origin showed greater rates of DNA synthesis and significantly elevated levels of proteoglycan, collagen, and noncollagen protein synthesis and Schiff base covalent collagen crosslink concentrations (dihydroxylysinonorleucine) compared with intrasynovial tendon grafts. It was not clear to what extent the increased activity in the extrasynovial graft was due to actual differences between the intrasynovial and extrasynovial tendons or to the responses of the connective tissue surrounding the extrasynovial tendon graft. Since both types of grafts demonstrated similar unaltered levels of collagen and protein content over time, these data suggest greater rates of matrix turnover in tendon grafts of extrasynovial origin than in those of intrasynovial origin. Coupled with previous findings showing increased cellular proliferation in extrasynovial tendon grafts, these data indicate that the process of translation to an intrasynovial environment necessitates a more active process of soft-tissue repair and remodeling when extrasynovial donor tendons are used.

Maintenance of the gliding surface of tendon autografts in dogs.

To determine whether there are differences in the extent to which the superficial cellular layers remain viable and contribute to the healing process, extra- and intrasynovial hindlimb donor tendons of 12 dogs (24 tendons) were labeled with 3H-thymidine in vitro and transferred to the medial and lateral toes of the forepaw. After transplantation, the distribution and amounts of remaining labeled cells within the healing tendon grafts were determined at 1 and 3 weeks after surgery by scintillation countings and autoradiographic examinations. The two types of tendon grafts showed different turnover rates for the elimination of labeled DNA. At 1 week, 25 percent of labeled DNA remained in the extrasynovial grafts and 65 percent in the intrasynovial grafts. The two types of tendon grafts also showed different healing responses histologically. Autradiographic examinations showed that the majority of labeled cells were located in the periphery of the control tendons and that the numbers of labeled cells within the newly proliferated superficial areas of both types of tendon grafts decreased over time. These findings indicate that intrasynovial flexor tendons may possess improved prerequisites for superficial cellular survival and tendon gliding following autogenous tendon grafting.

A preliminary scoring system for assessing the outcome of carpal tunnel release.

Multiple outcomes are assessed in most studies of carpal tunnel syndrome, yet there are no validated methods of synthesizing these distinct measures into a single global score. We report a global score in which outcomes were selected and weighted according to their independent association with patient satisfaction with the results of surgery. Preoperative and 3-month follow-up data were analyzed on 104 subjects in a randomized controlled trial of open vs endoscopic carpal tunnel release. Patient satisfaction with surgery and a variety of subjective and objective outcome parameters were measured. In multivariate analyses, independent correlates of dissatisfaction included persistent numbness and paresthesia, incisional pain at follow-up evaluation, and decrease in grip strength. A global score was calculated by rounding to the nearest integer the model coefficients for these three variables. The global score correlated with patient satisfaction with surgery and time until return to work or full activities in patients undergoing open carpal tunnel release.