Bromelain in the early phase of healing in acute crush Achilles tendon injury.

UNLABELLED: Bromelain, an enzyme extracted from the stem of the pineapple plant has been proposed as a treatment for reducing pain and swelling following acute muscle injuries but studies are yet to be done on its effect on tendon healing. This study therefore investigated the effects of bromelain on tenocyte proliferation and the tendon malondialdehyde (MDA) level in the early stage of healing in a crush injury to the Achilles tendon of Sprague-Dawley rats. Twenty four male rats were divided randomly into three groups; groups 2 and 3 had induced crush injury to the left Achilles tendon. Group 1; nil injury and nil treatment, Group 2; nil treatment, Group 3; oral bromelain treatment. Bromelain was given at a dosage of 7 mg/kg body weight daily over the first 14 days post-injury. On day 15 post injury, the animals were killed and the tendons excised and processed for histological study and MDA assay. The results showed a significant increase in the tenocyte population in the bromelain group; p < 0.05. There was, however, no significant difference in the MDA level. CONCLUSION: Based on this study, 600 GDU bromelain given once daily in acute tendon injury at a dosage of 7 mg/kg promoted healing by stimulating tenocyte proliferation.

Effects of torsion, detorsion and melatonin on testicular malondialdehyde level.

BACKGROUND: Unilateral testicular torsion is a cause of bilateral testicular damage, which has ischaemic and reperfusion components. The damage may involve lipid peroxidation leading to production of lipid peroxides in the testes, including malondialdehyde (MDA). OBJECTIVE: To investigate the MDA variations in the ipsilateral and contralateral testes following ischaemia-reperfusion and the effect of melatonin. METHODS: Mature adult male Sprague-Dawley rats were divided into 13 groups of 10 each. One control group underwent sham operation. Three groups were subjected to right sided testicular torsion by twisting the testes 720 degrees counterclockwise for one, three and five hours; three groups were subjected to de-torsion following torsion lasting one, three and five hours; three groups were treated with intra-peritoneal melatonin (1 mg/kg) before torsion lasting one, three and five hours, and three groups were treated with intra-peritoneal melatonin before de-torsion following torsion lasting one, three and five hours. At the end of the experiment all animals were sacrificed by decapitation and testes were collected for MDA level estimation. RESULTS: The MDA level was significantly higher in ipsilateral torted testis than the control testis in all groups (P < 0.05), with the levels increasing with the duration of torsion. Detorsion significantly increased the MDA level only if the initial torsion was for less than three hours. Melatonin did not significantly affect the MDA level in the ipsilateral testis if administered before torsion, but significantly reduced the level if administered before detorsion. CONCLUSION: Malondialdehyde levels are altered in the both testes following unilateral testicular torsion-detorsion injuries. The reperfusion component of the injury is significant and may be reduced by melatonin.

The effect of quinine and ascorbic acid on rat testes.

BACKGROUND: We have previously demonstrated that quinine is a testicular toxicant in Sprague-Dawley rat. OBJECTIVE: To describe the changes in the testicular levels of testosterone and lipid peroxidation secondary to quinine and ascorbic acid administration in rats. METHODS: Twenty male Sprague-Dawley rats per group were assigned to one of three treatment groups: 0 mg quinine and 0 mg ascorbic acid/kg body weight (control); 10 mg quinine/ kg BW; and 10 mg quinine plus 0.1 mg ascorbic acid/kg BW. Rats were intramuscularly administered their respective doses of quinine five days in a week and ascorbic acid three days in a week for eight weeks. All the animals were sacrificed at the end by decapitation. Seminal analysis was performed on tubular fluid from caudal epididymides. Evaluations were made for testicular levels of testosterone and lipid peroxidation through malondialdehyde (MDA). Testicular specimens were also processed for histology under light microscopy. RESULTS: Quinine significantly (p < 0.01) increased free radicals (from elevation of MDA) and decreased testosterone in the testis compared with those of the control group and those treated with a combination of quinine and ascorbic acid. The semen of rats treated with only quinine demonstrated a significantly (p < 0.001) lower sperm concentration and motility compared to the controls and those treated with quinine plus ascorbic acid. Microscopic examination of cross-sections of seminiferous tubules also showed that ascorbic acid partially protected against quinine -induced testicular effects. CONCLUSION: Ascorbic acid has beneficial effect and protects against quinine-induced testicular reduction of testosterone.

Quinine lowers serum and testicular testosterone in adult Sprague-Dawley rats.

We have earlier demonstrated that quinine (QU) is a testicular toxicant. This present study was aimed at evaluating the effects of QU on both the serum and testicular levels of testosterone (TT) in an attempt to elucidate one of the potential mechanisms of QU-induced testicular toxicity. Thirty adult male Sprague-Dawley rats weighing 180-200g were used and were randomly divided into 3 groups of 10 rats each. Rats in group 1 had distilled water. Rats in group 2 had QU only at the dose of 10 mg/kg body weight per day (5 days in a week) for 8 weeks. Rats in group 3 rats had 10 mg/kg of QU (5 days in week) and 0.05 mg/kg of TT (3 days in a week) for 8 weeks. All the animals were sacrificed at the end of 8 weeks by decapitation. Seminal analysis was done on the tubular fluid aspirated from the caudal epididymides. The two testes were excised, weighed, and volume estimated. One testis of each rat (0.25 g of tissue) was homogenized with Potassium Chloride and TT level determined in the supernatant of the homogenate, while the other testis was processed for histology. Morphometry was carried out by assessing the diameter, cross-sectional area, number of profiles per unit area, length density and numerical density of the seminiferous tubules, and the relative and absolute volume of testicular components. The serum levels of TT in all the animals were also determined at the time of sacrifice. Both the serum and testicular levels of TT in rats administered QU only were significantly (P < 0.001) lower than those of the control and QU plus TT-treated rats. We conclude that QU induces spermatogenic epithelial toxicity by possibly interfering with the steroidogenic function of the Leydig cell.

Effects of different cervical traction weights on neck pain and mobility.

AIMS AND OBJECTIVES: This study investigated the effects of 3 different traction weights on neck pain and range of motion/mobility. MATERIALS AND METHODS: Ninety subjects, 42 men and 48 women, with neck pain due to cervical spondylosis participated in the study. They were assigned into three groups, each of which was subjected to a different cervical traction(CT) weight namely: group A = 7.5% total body weight(TBW), group B = 10%TBW, and group C =15%TBW CT respectively. Pain intensity and neck mobility, pre-treatment and post-treatment, were assessed using visual analogue scale(VAS) and universal goniometer respectively. RESULTS: There was no significant difference(p < 0.05) pre-treatment, but existed post-treatment (p < 0.05) between the groups for neck pain and mobility. Nineteen subjects had reactions due to the CT application: 3,5 and 11 in groups A,B and C respectively. The least reactions were recorded with the use of 7.5% TBW traction and the highest with the 15% TBW traction. The 10%TBW CT recorded the most significant pain relief and neck flexibility/mobility compared with the 7.5% TBW and 15% TBW CT therapy. CONCLUSION: This study established the 10% TBW CT as the ideal weight with minimal side effects and with highest therapeutic efficacy. Therefore clinicians could adopt this weight in managing neck disorders requiring traction.

Effect of cervical traction on cardiovascular and selected ECG variables of cervical spondylosis patients using various weights.

BACKGROUND: There is currently no consensus among the clinicians regarding the tractive force to be employed during cervical traction (CT) that will correlate precisely with the percentage body weight of the patient and reduce the side effects associated with CT therapy. OBJECTIVE: This study therefore aimed to investigate the response of cervical spondylosis (CS) patients to different CT weights and to establish the effect of CT on the cardiovascular system of patients with cervical spondylosis (CS). METHODS: Sixty out of 78 subjects participated in the study. They were randomly assigned into three experimental groups A, B and C. Their systolic and diastolic blood pressures (SBP and DBP) and heart rates (HR) were measured. Rate pressure product (RPP) was calculated using standard equation18 and ECG recorded using the KENZ, 201 machine. Subjects' cardiovascular and ECG responses were monitored in a supine resting position (baseline) and under three experimental conditions using the subjects' 7.5% kg total body weights (TBW), 10% kg TBW and 15% TBW at different time intervals (5, 10 and 15 minutes respectively). RESULTS: Compared with the baseline values, there was a drop in SBP, DBP and RPP for all subjects in the three groups. The SBP, DBP and RPP alteration were not significant for the 7.5% TBW CT, but significant (p <0.05) for the 10% and 15% TBW tractions. The HR and ECG variables revealed no significant difference in all the groups, these results signified that the cardiac muscles were not adversely affected by any of the traction weights during application. Twenty subjects had side-effects including 5 subjects that terminated the treatment due to pain during the CT application. CONCLUSIONS: Cardiovascular alterations do occur during the application of cervical traction weights resulting in untoward patient's reactions. Efforts should be made to monitor the cardiovascular variables during and immediately after CT especially in "high risk" patients, that is, elderly patients and patients with unstable cardiovascular systems.

Morphometric and stereological assessment of the effects of long-term administration of quinine on the morphology of rat testis.

BACKGROUND AND OBJECTIVES: Quinine (QU) has been used worldwide in the suppression and treatment of malaria for more than 350 years. The aim of this study was to determine the long-term morphological response of the testis to long-term administration of QU using stereological parameters. MATERIALS AND METHODS: 64 adult male Sprague-Dawley rats weighing 180-200g were used. The animals were randomly divided into 8 groups of 8 rats each. Every experimental animal had intramuscular QU at a dose of 10mg/kg body weight per day (5 times in a week, with the exception of group 1 animals). Group 1 rats had QU for 1 week (7 days consecutively) and were sacrificed on the last day of injection. Groups 2 and 3 rats had QU for 4 and 6 weeks and were sacrificed at the end of the 4th and 6th week respectively. Group 4, 5, 6 and 7 rats had QU for 8 weeks and were sacrificed at the end of week 8, 12, 16 and 20 respectively. Group 8 animals constituted the controls and had equal volume of distilled water intramuscularly for 8 weeks. All sacrifices were by decapitation. The testes were carefully dissected out, their volumes measured, weighed and histological sections prepared. Morphometric assessment was carried out using the diameter, cross-sectional area, number of profiles per unit area, numerical density and volume density of the seminiferous tubules and the relative and absolute volume of the seminiferous epithelium, stroma and lumen of tubules. RESULTS: The results showed that there was a general destruction of cells of the seminiferous tubules and the testicular interstitium that persisted even after the discontinuation of QU and to the end of our experiment that lasted 20 weeks. CONCLUSION: We conclude that QU has deleterious effect on the seminiferous tubules of Sprague-Dawley rats, though the mechanism of damage is unclear.

Attenuation of quinine-induced testicular toxicity by ascorbic acid in rat: a stereological approach.

Quinine (QU), an alkaloid derived from the cinchona bark is presently the mainstay of treatment for severe malaria and nocturnal leg cramps. We have recently demonstrated that QU is toxic to testicular gonocytes and interstitial endocrinocytes. This present study sought to determine whether co-administration of ascorbic acid (AA) with QU will modify the deleterious effects of QU on the testes of Sprague-Dawley rats. 50 male Sprague-Dawley rats weighing 160-180g were used for the experiments. The animals were randomly divided into 5 groups of 10 rats each and were variously administered QU for 7 days, QU for 8 weeks, QU plus AA for 7 days, QU plus AA for 8 weeks and distilled water. They were all sacrificed on the 56th day. Histological slides of the testes were prepared and morphometric parameters that included diameter and cross-sectional area of the seminiferous tubules, number of profiles of seminiferous tubules per unit area of testis and numerical density of the seminiferous tubules, volume density and absolute volume of testicular components were determined using a systematic random scheme. Our results showed that the cytoarchitecture of seminiferous tubules of rats treated with QU only was grossly distorted, while that of rats that had both QU and AA was not significantly different from that of the controls. The testicular volume; diameter and cross-sectional area of seminiferous tubules; and the relative and absolute volume of seminiferous epithelium of QU-treated rats were significantly (P < 0.05) reduced, while those of QU plus AA-treated Ones were not significantly different from those of the controls. In contrast, the numerical density of the tubules were significantly (P < 0.05) increased in rats administered QU only, while it was not significantly different in the QU plus AA-treated and control rats. We conclude that co-administration of AA with QU could play an important role in the modulation of QU-induced testicular damage.

Standards of craniofacial dimension for an African population.

This is a study of 247 children, aged 1-5 years in whom Interpupillary distance (IP) and Cephalic Index have been estimated. A reference curve for UP was determined. The data were compared to those of other populations. It was concluded that the genetic component of the negro hypertelorism manifest with growth and not at birth. Secondly, the Nigerian child appeared to become dolicocephalic at an earlier age of two years than his caucasian counterpart. While the explanation for the relative hypertelorism is obscure, it is suggested that the earlier closure of the anterior fontanelle might be responsible for the early dolicocephalic skull shape.

Morphometric analysis of the effect of chloroquine on rat foetal lung maturation.

Pregnant Sprague-Dawley rats were injected with chloroquine phosphate (40mg/kg b. wt 1.p) in the late canalicular (day 20) and early terminal-sac (day 21) and sacrificed in the late terminal sac (day 22 = term) stage of foetal lung development. The control animal received normal saline. Morphometric evaluation of the lungs by light microscopy revealed three important exposure-related lesions. They were: (a) reduction in the volume density of parenchyma and saccular space, (b) reduction in the volume of an average saccule and, (c) an increase in the number of saccules per unit volume (Numerical Density). The observations suggest that chloroquine retards foetal lung maturation by reducing the saccular expansion which takes place immediately preterm. However, the possible practical implications are unclear.

An investigation into the effects of chloroquine on fertility of male rats.

We investigated the effect of chloroquine on the fertility of adult male rats. Rats were administered chloroquine at a daily intra-peritoneal dose of 10mg/kg body weight and 40mg/kg body weight per rat, five days a week for 16 weeks. Females mated with treated males showed a dose dependent decrease in the number of litter per female rat. In the in-vitro studies, more than 80% os spermatozoa were immotile in all concentrations of chloroquine tested. These results suggest that chloroquine brings about its antifertility effect by decreasing sperm motility.

The effects of chloroquine on pulmonary saccular growth near term.

The Antimalaria drug, chloroquine is an amphiphilic cationic compound and might therefore be suspected to interfere with foetal lung maturity as previously observed with other amphilphilic cationic drugs. Single doses of chloroquine phosphate (40mg/kg b. wt) was administered to pregnant rats on days 20 and 21 of gestation (term = 22 days). Morphometric analysis revealed a decrease in volume density (Vv) of parenchyma, saccular space and average saccular volume. Concurrent administration of single doses hydrocortisone on day 21 increased the Vv of the Parenchyma saccules and average saccular volume. This result suggests that the retardation of foetal lung maturity induced by chloroquine could be reversed by a concurrent administration of hydrocortisone. Questions concerning the mechanism by which these effects are produced must remain open.

Sterological estimation of seminiferous tubular dysfunction in chloroquine treated rats.

We have used the simple-point sampling of linear intercept lengths and the optical dissector method to describe the effects of chloroquine on rat testicular morphology. The rats were injected intraperitoneally with chloroquine phosphate (CQ), an antimalaria and amphiphilic drug known to induce generalized lipidosis. The result showed that CQ (10 mg/kg/day) treatment for 7 weeks significantly reduced (i) the weight of the testis, (ii) the daily sperm production count, (iii) the total spermatoid count per testis and (iv) the star volume of the seminiferous tubules. There was however an increase in the total spermatocyte count per testis. Together, these findings suggest that disruption of spermatogenesis accompanied a decrease in tubular size in CQ treated rats.

Chloroquine-induced retardation of foetal lung maturation in rats.

Chloroquine (CQ) is a widely used drug and its administration has been reported to increase surfactant- associated phospholipids in lungs. We have used histomorphometric techniques to study the effects of CQ on foetal lung maturation in rats. CQ (40mg/kg BW) or saline was administered to pregnant rats on days 20 and 21 of gestation. A third group received the same dose of CQ on days 20 and 21, and in addition, hydrocortisone (HD; 25 mg/kg BW) on day 21 of pregnancy. Foetuses were delivered by hysterotomy on day 22. The lungs were weighed, fixed in Bouin's fixative and embedded in paraffin. Morphometric studies were performed on 5 microns-thick sections. The lung weight/100g BW, the volume density of lung saccular spaces, and the cross-sectional area and volume of the saccular spaces were reduced but the numerical density of the saccules was not decreased in foetuses exposed to CQ. With the exception of lung weights, which were lower in the foetuses exposed to CQ and HD, there were no other differences between this group and that exposed to CQ only. The results suggest that CQ attenuates the expansion of saccular spaces which occurs in preparation for post-natal gaseous exchange, and thus CQ retards foetal lung maturation. Although HD further reduced lung weights as expected from its reported action on foetal lungs, it did not reverse the CQ-induced retardation in lung maturation.

Effect of methanolic seed extract of Momordica charantia on body weight and serum cholesterol level of male Sprague-Dawley rats.

BACKGROUND: A steady weight increase disproportionate to height is by far the most prevalent type of body weight imbalance (overweight and obesity) in apparently healthy individuals of growing age. Many subsisting weight-reduction regimes or formulations are ineffective. Therefore, an effective and affordable weight-reduction product will add to the options available for the management of weight-related conditions. OBJECTIVE: This study aimed to investigate the effects of graded oral doses of methanolic seed extract of Momordica charantia (MC) on the body weights and cholesterol levels of male rats. MATERIALS AND METHODS: Twenty adult male Sprague-Dawley rats, weighing 176 +/- 70 g, were used for this study. The animals, divided randomly into 4 groups (A-D) received daily graded oral doses of 15, 25 and 50 mg/100 g body weight of methanolic seed extract of MC, respectively, while Group D rats had distilled water for 56 days. The weights of the animals in each group were recorded weekly throughout the duration of the experiment. Serum cholesterol levels were assayed from blood obtained from a left ventricular puncture. RESULTS: Treatment of rats with MC extract resulted in a dose-dependent, statistically significant (p < 0.05; p < 0.01) reduction in the body weight compared to control. The mean serum cholesterol levels in response to graded doses of MC in the different groups A to C also showed a statistically significant decrease (p < 0.05) from the baseline control value of 4.4 +/- 1.0 mMol/L to 3.4 +/- 0.7, 2.5 +/- 0.4 and 2.0 +/- 1.3 mMol/L, respectively. CONCLUSIONS: Present study demonstrated that MC caused dose-dependent reductions in body weight and serum cholesterol concentration in male Sprague-Dawley rats. MC may, therefore, be useful in controlling body weight increase in individuals of growing age as well as be a potential agent in the management of overweight and obesity.

Effect of aqueous extract of the bark of Carica papaya on testicular histology in Sprague-Dawley rats.

BACKGROUND: Males generally have few options for controlling their fertility and these options are far from being satisfactory. There is a great need for research to develop more contraceptive modalities for males. OBJECTIVE: The overall aim of this research was to determine the histological responses of the testes of Sprague-Dawley rats to aqueous extract of bark of Carica papaya using a single daily dose of 100 mg/kg and also to investigate if these responses are reversible or not. MATERIALS AND METHODS: Sixty mature (6-8 weeks old) male Sprague-Dawley rats, divided into 2 equal groups, were used for this experiment. Group 1 rats were fed with 100 mg/kg/day of the extract for 4 and 8 weeks, while group 2 rats served as the control subjects. Each cauda epididymis of the rats was exteriorized, incised and sperm motility and count conducted on expressed fluid. The testes were harvested and processed for histological examination under light microscope. Phytochemical analysis was done to ascertain the main constituents in the extract, while the LD50 was conducted to guide in the dose of administration of the extract. A subgroup of the animals was allowed a recovery period of 8 weeks before sacrifice. RESULTS: The results showed that 500 mg/kg (LD50) of the extract of bark of Carica papaya produced signs of toxicity with mortality of 50% of the rats. The extract at a dose of 100 mg/kg caused histological changes ranging from seminiferous tubular distortion to outright destruction/ degeneration of the seminiferous tubules. In addition, the testicular interstitia of extract-treated rats showed disorganization and hypocellularity. The extract also caused a significant (p < 0.05) reduction in both sperm count and motility. There was no significant reversal of these antispermatogenic effects following a recovery period of 8 weeks. CONCLUSION: Aqueous extract of the bark of Carica papaya has deleterious effects on both the seminiferous tubules and testicular interstitium and deserves to be further investigated as a potential male contraceptive agent.

Intrasound therapy in tendon healing: is intensity a factor?

OBJECTIVE: This study investigated the effects of low- and high-intensity intrasound therapy (LITR and HITR, respectively) given once daily and twice daily on the morphology and oxidative stress in healing tendon tissue following an acute injury. METHODS: Eighty-five male rats, randomized into six groups were further subdivided into groups A, B, and C, except for Group 1 which was subdivided into A and B only. Groups 2-6 underwent an induced crush injury. The six groups were allocated to: serve as controls (Group 1), receive no treatment (Group 2), HITR twice daily (Group 3), HITR once daily (Group 4), LITR twice daily (Group 5), and LITR once daily (Group 6). Intrasound therapy (ITR) was commenced 24 hours postinjury and was given once daily or twice daily over the first 14 days postinjury. The animals in subgroups A and B were sacrificed on day 15 postinjury, and those in subgroup C were sacrificed on day 31 postinjury. The tendons were excised, and processed for histology and malondialdehyde (MDA) assay. RESULTS: There was no significant difference in the tenocyte population between the HITR- and LITR-treated groups. However, twice-daily treatment in either the low- or high-intensity mode resulted in significant tenocyte proliferation compared with the once-daily treated groups, and also had the highest percentage of tenoblasts compared with the population of tenocytes in the proliferative phase of healing. All treatment protocols marginally lowered the MDA level. CONCLUSION: The role of IRT in tendon healing is influenced more by the frequency of treatment rather than the intensity of the delivered dosage.

The role of aqueous extract of pineapple fruit parts on the healing of acute crush tendon injury.

BACKGROUND: The Pineapple plant contains the enzyme bromelain which has been acclaimed to reduce pain and swellings following acute muscle injuries as well as carotenoids and polyphenols which are powerful antioxidants. It is yet to be determined if these constituents are distributed throughout the plant and what effect they have on the healing of acute tendon injuries. OBJECTIVE: This study therefore investigated the effects of the aqueous extract of different parts of the pineapple plant on tenoblast proliferation and the tendon Malondialdehyde (MDA) level in the early stage of healing in a crush injury to the achilles tendon of Sprague-Dawley rats. METHODS: Forty male rats were divided randomly into five groups; all had induced crush injury to the left Achilles tendon. Group 1; injury and nil treatment, Group 2; leaves extract, Group 3; fruit flesh extract, Group 4; bark extract, Group 5; core extract. The extract was given at a dosage of 30 mg/kg body weight daily over the first 14 days post-injury. On the 15th day post injury, the animals were sacrificed and the tendons excised and processed for histological study and MDA assay. RESULTS: The flesh and bark extract induced a proliferation of tenoblasts which however was not significantly different from that of the untreated tendon while the leaves and core extracts reduced the population of the tenocytes. The flesh extract significantly (p < 0.05) reduced the MDA level while the leaves and core extract significantly (p < 0.001) increased it. The bark extract had no significant impact on the MDA level compared with the untreated tendon. CONCLUSION: This study suggests that the anti-oxidant constituents of the pineapple plant are concentrated in the flesh while the bark and flesh extracts have the potential to promote healing by stimulating tenoblast proliferation.

The effects of varied intensities of intrasound therapy with indomethacin on the morphology of the healing tendon.

BACKGROUND: Patients undergoing intrasound therapy are often concurrently on NSAIDs. The effect of varied intensities of intrasound therapy with NSAIDs on tendon healing is yet to be determined. OBJECTIVE: The study investigated the effects of a concurrent admistration of low and high intensity intrasound therapy (LIRT&HIRT) with indomethacin (Indocid) on the morphology of the tendon in the early stage of healing. METHODS: Thirty five male rats were divided randomly into seven groups; groups 2-6 underwent an induced crush injury. Group 1, nil injury and nil treatment. Group 2: injury but nil treatment. Group 3: Indomethacin only. Group 4: LIRT only, Group 5: Indocidand LIRT, Group 6: HIRT, Group 7: Indocid and HIRT. Intrasound therapy (IRT) commenced 24 hours post-injury and was given alternate days for the first 10 days post injury. Indocid was given at a dosage of 0.4 mg/kg body weight daily. On the 11 day post injury, the animals were sacrificed and the tendons excised and processed for histological study. RESULTS: Indocid significantly (p < 0.05) reduced the tenocyte population when combined with LIRT but marginally increased it when combined with HIRT (p > 0.05). There was significant difference in the tenocyte population between the combined Indocid and LIRT and the combined Indocid and HIRT groups (p < 0.05). CONCLUSION: High intensity intrasound given concurrently with oral indomethacin resulted in tenoblast proliferation and promoted healing in the injured tendon.