Effect of growth factors on the proliferation of ligament fibroblasts from skeletally mature rabbits

Growth factors have been shown to stimulate fibroblast proliferation during wound and ligament healing. In this study, we analyzed individual effects of eight growth factors in vitro on the proliferation of fibroblasts from the medial collateral (MCL) and anterior cruciate (ACL) ligaments of skeletally mature rabbits. We compared the proliferative response of growth factor-treated and nontreated fibroblasts of both ligaments. The growth-factor treated fibroblasts of the MCL and ACL were also compared. We found that the fibroblasts exposed to epidermal growth factor, basic fibroblast growth factor and platelet-derived growth factor-BB proliferated significantly more than untreated fibroblasts. Acidic fibroblast growth factor at a dose of 1.0 ng/ml caused significant increases in fibroblast proliferation only in the MCL. Transforming growth factor-beta 1, insulin-like growth factor-1, platelet-derived growth factor-AA, and interleukin-1 alpha did not significantly stimulate fibroblast proliferation. MCL fibroblasts generally did not proliferate significantly more than ACL fibroblasts with the exception of MCL fibroblasts exposed to the highest doses of basic fibroblast growth factor, acidic fibroblast growth factor and platelet-derived growth factor-BB. The data were also compared with those obtained earlier using fibroblasts from skeletally immature rabbits (Schmidt et al., JOR 1995). The proliferative response of both the MCL and the ACL fibroblasts was found to decrease with skeletal maturation. Thus, our findings suggest that animal age and fibroblast origin are important factors in determining the proliferative response to growth factors.

Hemodynamics, intramucosal pH and regulators of circulation during perioperative epidural analgesia

PURPOSE

To evaluate the effects of perioperative epidural analgesia on hemodynamics, splanchnic perfusion and regulators of circulation.

METHODS

Twenty patients undergoing aortic surgery were randomised into two groups: epidural analgesia group (EAG): epidural analgesia with bupivacaine (15 ml, 0.125%) was started before surgery. Eight and 16 hr postoperatively 10 ml bupivacaine 0.125% and 1 mg morphine were given. Control group (COG): patients received no epidural catheter. Monitoring included pulmonary artery catheter and gastric tonometer. Norepinephrine, epinephrine, renin, ADH, ANP and endothelin were measured: before epidural analgesia (T0), before aortic clamping (T1), 20 min after aortic clamping (T2), after declamping the first leg (T3), at end of surgery (T4), one hour (T5) and 24 hr postoperatively (T6).

RESULTS

At T5 mean arterial blood pressure decreased in EAG compared with baseline (86 +/- 16 to 75 +/- 8 mmHg) and compared with COG (75 +/- 8 vs 84 +/- 11 mmHg). At T2 pulmonary capillary wedge pressure and cardiac index increased and at T6 decreased in both groups. Systemic vascular resistance decreased at T I and at T3-T5 in EAG compared with COG and at T1 and T3-T6 to baseline (1472 +/- 448 to 1027 +/- 184 dyn x sec x cm(-5) x m(-2)). In EAG and in COG, pHi decreased compared with baseline but without group differences. In both groups, epinephrine, norepinephrine, renin, and ADH levels increased from baseline. Endothelin and ANP levels showed no changes.

CONCLUSIONS

Perioperatively administrated epidural bupivacaine has no beneficially effects on hemodynamics, pHi or release of regulators of circulation.

Low-flow desflurane and sevoflurane anesthesia minimally affect hepatic integrity and function in elderly patients

Hepatic blood flow is reduced in a dose-related manner by all inhaled anesthetics now in use. We assessed hepatic function in elderly patients anesthetized with desflurane or sevoflurane. We measured the cytosolic liver enzyme alpha glutathione S-transferase (alpha GST), the formation of the lidocaine metabolite monoethylglycinexylidide (MEGX), and gastric mucosal tonometry-derived variables as sensitive markers of hepatic function and splanchnic perfusion. Thirty patients, 70 to 90 yr old, were allocated randomly to receive desflurane or sevoflurane anesthesia. Anesthetic exposure ranged from 2.1-4.5 minimum alveolar concentration hours. No significant changes in standard liver enzyme markers were seen throughout the study. In both anesthetic groups, tonometric measurements showed a significant decrease from baseline in regional PCO(2), regional to arterial difference in PCO(2), and intramucosal pH at 90 min after skin incision. alpha GST concentrations increased significantly in both groups (desflurane: median peak concentrations 5.8 microg/L [25th, 75th percentile 5.3 microg/L, 7.2 microg/L]; sevoflurane: 7.0 microg/L [5.8 microg/L, 7.3 microg/L]) without showing differences between both anesthetic groups. A return to baseline values in tonometric values and alpha GST levels was seen 24 h postoperatively. MEGX formation did not change significantly after surgery. Median MEGX concentrations postoperatively were 70.0 ng/mL (56.2 ng/mL, 102.0 ng/mL) and 70.0 ng/mL (60.0 ng/mL, 94.2 ng/mL) in the desflurane and sevoflurane groups, respectively. We conclude that, overall, liver function in elderly patients is well preserved during desflurane and sevoflurane anesthesia. Increased serum levels of alpha GST and changes of gastric tonometry-derived variables imply a reduction in splanchnic perfusion, leading to a temporary impairment of hepatocyte oxygenation.

IMPLICATIONS

We measured the lidocaine metabolite monoethylglycinexylidide, the cytosolic liver enzyme, alpha glutathione S-transferase, and gastric mucosal tonometry-derived variables to evaluate the effects of desflurane and sevoflurane on hepatic function in elderly patients. Liver function was well preserved, whereas increased alpha glutathione S-transferase levels and changes in tonometry-derived variables indicated a reduction in splanchnic blood flow and a temporary impairment of hepatocyte oxygenation for both anesthetics.

Influence of dopexamine on hemodynamics, intramucosal pH, and regulators of the macrocirculation and microcirculation in patients undergoing abdominal aortic surgery

OBJECTIVE

To investigate whether dopexamine hydrochloride beneficially influences splanchnic perfusion and regulators of the macrocirculation and microcirculation in patients undergoing surgery of the abdominal aorta.

DESIGN

Prospective, blinded, and randomized study.

SETTING

University-affiliated hospital.

PARTICIPANTS

Twenty patients undergoing elective abdominal aortic surgery.

INTERVENTIONS

The patients were randomized to one of two groups. In the dopexamine group (DOP, n = 10), dopexamine, 1 microg/kg/min, was started before surgery and continued for 24 hours. In the control group (COG, n = 10), patients received saline solution as placebo. Extensive hemodynamic monitoring was carried out using a pulmonary artery catheter, and intramucosal pH was measured using a gastric tonometer. From arterial blood samples, important regulators of the circulation were measured before dopexamine was administered (T0), before aortic clamping (T1), 20 minutes after aortic clamping (T2), after declamping the first leg (T3), at the end of surgery (T4), 1 hour postoperatively (T5), and 24 hours postoperatively (T6).

MEASUREMENTS AND MAIN RESULTS

Heart rate increased significantly in DOP (63+/-16 to 84+/-18 beats/min). At T5, mean pulmonary artery pressure was significantly lower in DOP (15+/-6 mmHg) than in COG (22+/-6 mmHg). During aortic clamping, pulmonary capillary wedge pressure increased significantly in both groups. Cardiac index increased significantly from baseline only in the dopexamine patients. No significant differences between the groups were seen with regard to oxygenation parameters and intramucosal pH. Renin plasma levels increased significantly only in COG (46+/-32 to 99+/-55 microU/mL). Endothelin and atrial natriuretic peptide plasma levels showed no significant differences between the two groups. Atrial natriuretic peptide increased significantly only in DOP (366+/-171 pg/mL; COG, 159+/-71 pg/mL). Antidiuretic hormone, norepinephrine, and epinephrine plasma levels increased significantly from baseline in both groups, without showing significant differences between the groups.

CONCLUSIONS

In patients undergoing abdominal aortic surgery, prophylactic perioperative administration of dopexamine hydrochloride produced effects on hemodynamics but without improving oxygenation and intramucosal pH. From the measured regulators of the circulation, only renin was beneficially affected.

Basal joint arthroplasty using an allograft tendon interposition versus no interposition: a radiographic, vascular, and histologic study

To assess the role of a tendon spacer that fills the trapezial void, the trapeziums were excised and anterior oblique ligaments were reconstructed in 25 monkeys. In addition to the ligament reconstruction, 20 of the monkeys had the trapezial void filled with a tendon allograft. The trapezial space was investigated at 0, 3, 6, 15, and 40 weeks using routine histologic staining, arterial perfusion (Spalteholz), and standardized radiographs. There was a statistically greater decline in trapezial height in the animals without tendon interposition allografts. The tendon grafts became progressively neovascularized and populated with fibroblasts. By 40 weeks, the allograft was no longer a folded tendon but a homogeneous mass of collagen, fibroblasts, and capillaries. The specimens without an interpositional tendon graft had loose fibroadipose tissue filling the carpal void. Polarized light microscopy showed fibers crossing the subchondral bone and moving into the adjacent fibrous spacer in the specimens implanted with a tendon graft. The results indicate that filling the trapezial void with an interposition tendon spacer may aid in maintaining normal wrist anatomy.

A comparison of urapidil, clonidine, meperidine and placebo in preventing postanesthetic shivering

This placebo-controlled study was performed to evaluate the efficacy of urapidil compared with clonidine and meperidine in preventing postanesthetic shivering, which is common after anesthesia administration and may be very distressing. We studied 120 patients undergoing elective abdominal or orthopedic surgery under standardized general anesthesia. After surgery, patients were randomly assigned to one of four groups (each group n = 30) using a double-blinded protocol: Group A received 0.2 mg/kg urapidil; Group B, 3 microg/kg clonidine; Group C, 0.4 mg/kg meperidine; and Group D, saline 0.9% as placebo. Postanesthetic shivering was scored by using a five-point scale. Clonidine and meperidine significantly reduced the incidence and the severity of shivering in comparison with placebo, whereas there were no significant differences between the urapidil and placebo groups. Both clonidine and meperidine caused a significantly prolonged emergence time (13.4 +/- 5.8 and 13. 3 +/- 5.0 min, respectively) compared with placebo (10.4 +/- 5.3 min) and urapidil (11.4 +/- 2.9 min). We confirmed that both clonidine and meperidine are effective in preventing postanesthetic shivering, whereas urapidil, in our setting and dosage, was not effective. Patients who received clonidine or meperidine had a prolonged emergence time. In the dosage used, urapidil seems to be unable to prevent postanesthetic shivering.

IMPLICATIONS

Shivering (irregular muscle activity) is common after surgery and anesthesia. This study compared urapidil (an antihypertensive drug) as a prophylaxis with two established antishivering drugs (meperidine and clonidine) and placebo. In the dosage used, we were unable to show a significant benefit of urapidil.

Acute phase response to nitroprusside-induced controlled hypotension in patients undergoing radical prostatectomy

This study evaluated the effects of sodium nitroprusside-induced controlled hypotension on the acute phase response in patients undergoing radical prostatectomy. Thirty patients were randomly allocated to two groups, a hypotension group (mean arterial blood pressure was adjusted to 50 mmHg) and a control group (mean arterial blood pressure > 70 mmHg). C-reactive protein increased significantly in the hypotension group from 0.13 (0.23) to 9.85 (2.84) microg x ml-1 and in the control group from 0.15 (0.27) to 7.38 (3.02) microg x ml-1. In both groups, serum amyloid A increased significantly, but levels were higher in the hypotension group [585 (125) microg x l-1] than in the control group [460 (187) microg x l-1]. Interleukin-6 increased significantly in both groups, but was higher in the hypotension group [139 (124) pg x ml-1] than the control group [56 (27) pg x ml-1]. Elastase showed no significant changes in the control group but in the hypotension group there was a significant increase from 65 (51) to 122 (75) ng x ml-1. Sodium nitroprusside-induced hypotension was associated with a more pronounced acute phase reaction.

The effects of sodium nitroprusside-induced hypotension on splanchnic perfusion and hepatocellular integrity

The purpose of our study was to investigate the effects of sodium nitroprusside-induced hypotension on splanchnic perfusion and hepatocellular integrity. Thirty patients undergoing radical prostatectomy were allocated randomly to a sodium nitroprusside (SNP) or control group (control). Regional pco2 was measured using gastric tonometry, and the regional to arterial difference in partial pressure of CO2 and intramucosal pH were calculated. The cytosolic liver enzyme alpha-glutathione S-transferase and standard liver enzyme markers (alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyltransferase) were also measured. Mean arterial pressure in the SNP group was 50 mm Hg for 97 min during surgery. A significant increase from baseline in regional pco2 (from 40.0+/-4.2 mm Hg to 45.3+/-1.3 mm Hg) and regional to arterial difference in partial pressure of CO2 (from 4.1+/-1.1 mm Hg to 9.7+/-1.4 mm Hg) was seen at 90 min after skin incision only in the SNP group. Intramucosal pH decreased significantly from 7.40+/-0.02 to 7.35+/-0.03 during the same period in this group. Tonometric variables returned to baseline values within 2 h postoperatively. Alpha-glutathione S-transferase concentrations increased significantly in the SNP group from baseline to peak concentrations at the end of surgery (SNP: 9.93+/-4.94 microg/L; control: 5.85+/-1.86 microg/L). A return to baseline values was seen 24 h postoperatively. No significant changes in standard liver enzyme markers were seen throughout the study period. It is concluded, that splanchnic perfusion was transiently impaired during controlled hypotension. This is supported by significant changes in tonometric data. Increased serum levels of alpha-glutathione S-transferase may indicate a disturbance in hepatocellular integrity.

IMPLICATIONS

We studied gastric mucosal tonometry and the cytosolic liver enzyme alpha-glutathione S-transferase to evaluate the effects of controlled hypotension induced by sodium nitroprusside on splanchnic perfusion and hepatocellular integrity. Splanchnic perfusion decreased and alpha-glutathione S-transferase increased during and after a hypotensive period, but returned to baseline values within the first postoperative day, indicating a transient impairment of splanchnic perfusion and hepatocellular integrity.

Comparison of the effects of desflurane and isoflurane anaesthesia on hepatocellular function assessed by alpha glutathione S-transferase

The purpose of this study was to investigate the influence of isoflurane and desflurane on hepatocellular function. Twenty male patients undergoing elective surgery were randomly assigned to receive either isoflurane or desflurane anaesthesia. Alpha glutathione S-transferase concentrations and aminotransferase activities were measured at induction of anaesthesia (t0), 15 min (t1), 90 min after induction (t2), end of surgery (t3) and 2 h thereafter (t4). A significant increase in alpha glutathione S-transferase concentration was observed only in the isoflurane group. Alpha glutathione S-transferase levels increased significantly from 2.3 microg.l-1 at t0 to 6.1 (1.9) microg.l-1 at t2 and to 7.8 (2.1) microg.l-1 at t3. A significant difference in alpha glutathione S-transferase concentration between the two groups was found at t2 and t3. The significant increases in alpha glutathione S-transferase concentrations in patients receiving isoflurane suggest a transient disturbance of hepatocellular function.

Nefopam and clonidine in the prevention of postanaesthetic shivering

Postanaesthetic shivering affects up to 70% of patients after general anaesthesia, and may be very distressing. Various drugs have been used to treat or prevent postanaesthetic shivering, but the ideal one has not yet been found. Sixty patients undergoing elective abdominal or orthopaedic surgery under general anaesthesia were included in a randomised, double-blind study. Patients received clonidine (3 microgram.kg-1), nefopam (0.15 mg.kg-1) or saline 0.9% as a placebo at the end of surgery, prior to extubation. Nefopam and clonidine significantly reduced the incidence and severity of shivering in comparison with the placebo. The recovery time, between the end of anaesthesia and extubation, was significantly longer in the clonidine-treated patients [13.6 (5.2) min] than in either the nefopam [9.6 (2.8) min] or the placebo [10.0 (5.4) min] groups. Mean arterial blood pressure and heart rate were significantly lower in the clonidine group compared with both other groups. Our results suggest that nefopam and clonidine are effective in the prevention of postanaesthetic shivering. However, following clonidine administration the recovery time was prolonged and hypotension was significantly greater than after nefopam.

[Prevention of postoperative nausea and vomiting after hysterectomy with oral dolasetron, intravenous dehydrobenzperidol or a combination of both substances]

OBJECTIVE

PONV is a frequent postoperative complication. The aim of this study was to assess the efficacy of oral dolasetron in comparison to intravenous droperidol (DHB) and to a combination of both drugs for prophylaxis of PONV.

METHODS

80 patients (ASA I-III) were randomly allocated to one of four groups and received the following medication: group A: 50 mg dolasetron was given orally 45-60 minutes before anaesthesia was induced, group B: 2.5 mg i.v. DHB + placebo p.o. was administered while inducing anaesthesia (positive control group), group C: 50 mg dolasetron was given 45-60 minutes before anaesthesia was induced and 2.5 mg i.v. DHB was given while inducing anaesthesia, group D: placebo tablet was administered 45-60 minutes before anaesthesia was induced (negative control group). PONV was assessed using a 5-point score: 0 = no symptoms, 1 = nausea, 2 = retching, 3 = vomiting, 4 = multiple vomiting. Metoclopramid was given as antiemetic if a patient reached two or more score points.

RESULTS

PONV scores were significantly lower in group A and C (p < 0.001) compared to the control group. Patients treated with DHB showed a significantly lower PONV score in comparison to the placebo treated patients (p < 0.05). Between the groups A, B and C we found no significantly different PONV scores. Postoperative consumption of metoclopramid was significantly lower in the groups A (2.4 +/- 5.2 mg) and C (1.0 +/- 3.1 mg) than in the placebo group (6.0 +/- 6.8 mg), whereas between group B (3.0 +/- 5.7 mg) and D we found no significant differences.

CONCLUSIONS

Single dose of oral dolasetron and single dose of intravenous DHB reduced PONV effectively, in patients undergoing gynaecologic surgery. A combination of dolasetron and DHB has no better effect than a single dose of oral dolasetron. Contrary to DHB the application of dolasetron decreased the postoperative antiemetic requirement significantly.

The anconeus muscle flap: its anatomy and clinical application

The arterial anatomy, coverage area, and potential donor site morbidity of the anconeus muscle flap are described. Using 17 cadaveric upper extremities, we investigated the muscle's arterial anatomy in 12 specimens and defined the coverage area of the anconeus flap in 5 specimens. We also reviewed the records of 9 patients who underwent a pedicle anconeus muscle flap for elbow coverage to assess clinical results of the procedure. The anconeus muscle is supplied from 3 arterial pedicles: the recurrent posterior interosseus artery, the medial collateral artery, and the posterior branch of the radial collateral artery. The recurrent posterior interosseus artery and the medial collateral artery were present in all dissected cadavers and consistently anastomosed with each other underneath the anconeus muscle. By harvesting the muscle on the medial collateral artery, the anconeus muscle flap can be expected to cover a 7.3 cm2 defect over the radiocapitellar joint, a 6.1 cm2 defect over the distal triceps tendon, and a 7.2 cm2 defect over the olecranon. In this series, none of the patients experienced loss of elbow motion, stability, or extension strength. The results of this study indicate that the anconeus can be harvested with minimal risk of morbidity and provides effective coverage for soft tissue defects of the elbow.

[Neurologic symptoms in acute thoracic aortic dissection--a case report]

Acute thoracic aortic dissection is a life-threatening illness. It is often difficult to diagnose preclinically due to its many possible symptoms. One out of three patients has neurological deficits. The prognosis depends on rapid diagnosis and immediate adequate therapy. Therefore, every emergency physician should know the signs and risk factors of this disease. The most important goals of prehospital therapy are management of pain and anxiety and pharmacological control of the systolic blood pressure and heart rate. We report on a 46-year-old female patient who developed neurological deficits caused by an acute thoracic aortic dissection.

[Prophylactic nefopam administration for post-anesthetic shivering]

PURPOSE

Shivering is a frequent postanaesthetic complication. Its definite reason is unknown. Patients with cardiovascular or pulmonary diseases are endangered by postanaesthetic shivering. The aim of this study was to assess the efficacy of nefopam in prophylaxis of shivering. Additionally we investigated the influence of nefopam on haemodynamic parameters and on the time until extubation.

METHODS

30 patients (ASA I-II) were randomly allocated in a double-blind fashion to one of two groups to receive directly after the end of isoflurane application either nefopam (0.15 mg/kg) or placebo (0.9% saline). The period of anaesthesia had to be longer than 60 minutes. All patients received a premedication with lorazepam (0.02 mg/kg) 30-45 minutes prior to surgery. Induction of anaesthesia was standardised: fentanyl (3 micrograms/kg), thiopentone (5 mg/kg), atracurium (0.4 mg/kg). Intraoperatively a mixture of isoflurane, nitrous oxide (60%) and oxygen was used to maintain anaesthesia. The following parameters were evaluated: Age, sex, duration of operation and anaesthesia and the time between the end of application of volatiles and extubation. Heart rate (HR), mean arterial blood pressure (MAP), rectal temperature and O2-saturation were measured at predefined data points. Postoperatively the consumption of analgesic was documented. The severity of shivering was classified in five grades.

RESULTS

In the control-group nine patients shivered (60%), whereas in the nefopam group only one patient (6.6%) shivered (p < 0.05). In comparison to the placebo group we observed in the nefopam group a significantly decreased HR 30 and 60 minutes postoperatively (p < or = 0.007 and p < or = 0.002). We did not observe prolonged awakening in the nefopam-treated patients. MAP and O2-saturation showed similar reactions in both groups.

CONCLUSION

The data indicate that prophylactic administration of nefopam can suppress postanaesthetic shivering. Prolonged awakening was not observed.

Pyogenic flexor tenosynovitis

The clinical features of an infected finger flexor tendon sheath have changed dramatically since the pre-antibiotic time of Kanavel. The hand surgeon is encountering increasing numbers of gram-negative and mixed organism infections, especially in immunocompromised patients or those with comorbidities such as diabetes mellitus. The prognosis is directly related to the early recognition of the disease process and prompt surgical drainage and sheath irrigation, in combination with an appropriate antibiotic regimen. Despite appropriate management, some patients still develop significant complications. This possibility must be particularly recognized in diabetic and immunocompromised patient populations.

The effects of platelet-derived growth factor-BB on healing of the rabbit medial collateral ligament. An in vivo study

We report a biologic approach to improve medial collateral ligament healing using growth factors normally expressed in healing tissue. Our previous in vitro work demonstrated that platelet-derived growth factor-BB and transforming growth factor-beta 1 promoted fibroblast proliferation and matrix synthesis, respectively. There-fore, these growth factors were used in vivo to determine whether they could improve medial collateral ligament healing, whether this effect was dose-dependent, and if combinations of growth factors could improve healing more than individual growth factors. Thirty-seven rabbits had various doses of growth factors applied to the ruptured right medial collateral ligaments using a fibrin sealant delivery vehicle. The five groups consisted of 1) two groups receiving two doses of platelet-derived growth factor-BB, 2) two groups receiving two doses of this growth factor plus transforming growth factor-beta 1, and 3) one group receiving fibrin sealant only. After sacrifice at 6 weeks, biomechanical and histologic evaluations of the healing ligament were performed. Femur-medial collateral ligament-tibia complexes of the knees given the higher dose of platelet-derived growth factor-BB had ultimate load, energy absorbed to failure, and ultimate elongation values that were 1.6, 2.4, and 1.6 times greater than the same complexes of the control group. Adding transforming growth factor-beta 1 did not lead to any further increase in the structural properties of the complex compared with treatment with platelet-derived growth factor-BB. These encouraging results suggest that use of platelet-derived growth factor-BB may improve the quality of the healing medial collateral ligament, and that it may also have a similar potential for promoting healing of other ligaments.

Ulnar ray deficiency

Longitudinal deficiencies of the ulna are very rare deformities. Despite the cosmetic appearance, patients usually have very functional extremities. The limb function has been adversely related to ipsilateral hand deformities and radiohumeral synostosis. Surgical treatment should be aimed at correcting such deformities. It is prudent to wait and observe patients before definitive wrist or forearm treatment is recommended.

Who decides the law of the land?

A cornerstone of American-Indian cultures is a deep sense of interconnectedness with the natural environment. To preserve this sense of interconnectedness on tribal lands, many American Indians believe that sovereignty over environmental affairs on tribal lands is essential. But a number of shortcomings have historically and continually weakened tribal authority, and years of federal neglect have left most tribes unprepared to deal with their environmental problems.

Effect of partial laceration on the structural properties of the canine FDP tendon: an in vitro study

The appropriate management of partially lacerated digital flexor tendons in zone 2 is controversial. Tenorrhaphy has been advocated by some on the basis of improving tendon gliding function, whereas others have recommended foregoing tenorrhaphy because of the negative impact of repair on the tensile strength of the tendon. In light of this division, we undertook a study of the effect of varying degrees of partial laceration on the structural properties of the canine flexor digitorum profundus tendon. Lacerations up to 90% of the tendon cross-sectional area were surgically fashioned. We conclude that the structural properties of the tendon are increasingly adversely affected as laceration size increases. However, based on previous estimates of in vivo forces, even tendons with up to 60% cross-sectional area involvement may be strong enough to withstand an early active mobilization regimen. Further, we conclude that neither calipers nor naked-eye estimates provide a reliable means of assessing the extent of tendon laceration.

Healing of the medial collateral ligament after a combined medial collateral and anterior cruciate ligament injury and reconstruction of the anterior cruciate ligament: comparison of repair and nonrepair of medial collateral ligament tears in rabbits

The optimal treatment for a combined injury of the medial collateral and anterior cruciate ligaments is controversial, and the question remains as to whether repair of the medial collateral ligament and reconstruction of the anterior cruciate ligament improves healing of the medial collateral ligament. We compared reconstruction of the anterior cruciate ligament with and without repair of the medial collateral ligament in a rabbit model of a combined injury of these two ligaments. The anterior-posterior translation and varus-valgus rotation of the knee, the structural properties of the femur-medial collateral ligament-tibia complex, and the mechanical properties of the midsubstance of the medial collateral ligament were evaluated immediately after surgery and at 6 and 12 weeks postoperatively. Repair of the medial collateral ligament led to significantly less varus-valgus rotation of the knee than did no repair, but the anterior-posterior translation of the knees in the repair and nonrepair groups were not significantly different at any study time. At 12 weeks, the cross-sectional area and ultimate load in the repair group were 60 and 53% greater, respectively, than in the nonrepair group. Among 12 specimens that were repaired (six specimens at 6 weeks and six specimens at 12 weeks), failure occurred within the midsubstance in four (two at each time period); in all of the specimens that were not repaired, failure occurred at the tibial insertion site. There was no significant difference between the modulus of the modulus of the midsubstance in the repaired and the nonrepaired medial collateral ligaments.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of growth factors on the proliferation of fibroblasts from the medial collateral and anterior cruciate ligaments

Growth factors have been shown to stimulate fibroblast division and thus may influence ligament healing. We analyzed the effects of individual growth factors on the proliferation of fibroblasts from the medial collateral and anterior cruciate ligaments of the rabbit in vitro in order to identify growth factors that might enhance proliferation of fibroblasts and to compare the responses of the fibroblasts from the two ligaments to these growth factors. Through measurement of the uptake of [3H]-thymidine into DNA, fibroblasts from these ligaments that had been treated with epidermal growth factor and basic fibroblast growth factor were found to proliferate nearly eight times more than control fibroblasts. Additionally, the fibroblasts of both ligaments proliferated at similar rates when exposed to platelet-derived growth factor-AA, platelet-derived growth factor-BB, basic fibroblast growth factor, insulin-like growth factor-1, and interleukin-1-alpha. However, epidermal growth factor and transforming growth factor-beta caused the fibroblasts from the medial collateral ligament to proliferate at a rate 1.3-1.4 times greater than that of fibroblasts from the anterior cruciate ligament. The reverse was true with acidic fibroblast growth factor, which stimulated the fibroblasts from the anterior cruciate ligament to proliferate at a rate 1.3-1.6 times greater than that of fibroblasts from the medial collateral ligament. This study demonstrated that growth factors can stimulate cell division in ligaments and may be effective in enhancing ligament healing but that these differences were not great enough to explain fully the clinical differences observed between healing of the medial collateral and anterior cruciate ligaments.

Non-extensile surgical approaches for two-column acetabular fractures

We reviewed the outcome, at a mean follow-up of 14 months, of 21 two-column fractures of the acetabulum treated by operation through one or two non-extensile approaches. Eighteen procedures resulted in reduction of the articular surfaces to within 3 mm. The blood loss and operating time when two combined non-extensile approaches were used were similar to those reported for extended acetabular approaches. The incidence of heterotopic ossification which limited joint motion was low, and the average Harris hip score was 81 points. The use of non-extensile approaches for acetabular fractures in which both columns are involved avoids iatrogenic injury to the abductors, and reduces the incidence of complications.

Choice of anesthetic alters the circulatory shock pattern as gauged by conscious rat endotoxemia

A standardized rat endotoxin shock model was used to assess the differential effects of four commonly used anesthetics upon hemodynamics before and during endotoxin shock. Forty-nine male Sprague-Dawley rats weighing 307 +/- 4 g were divided into five groups:freely-moving conscious, enflurane (2%), isoflurane (1.4%), pentobarbital (6 mg.kg-1.h-1 i.v.), and ketamine (45 mg.kg-1.h-1 i.v.). Anesthetic doses were chosen as 1.0 MAC equivalent. Anesthetized rats were intubated and ventilated with oxygen. The right carotid artery was cannulated with a thermocouple-catheter for aortic blood pressure, heart rate, and thermodilution cardiac output measurements. The right jugular vein was cannulated for measurement of central venous pressure and for i.v. injections. Data were collected over a 30-min baseline period and for 4 h after an i.v. bolus of endotoxin (40 mg.kg-1, LD100 within 24 h). Gross small intestinal pathology was rated on a 0-4 scale. Anesthetic effects were judged in terms of significant deviations from the awake data on each parameter. Despite differing patterns, total deviations were similar for enflurane, ketamine, and pentobarbital, although the latter drug was the least preferable due to particularly high systemic vascular resistance. Significantly less hemorrhagic small intestinal pathology occurred with enflurane. Ketamine offered no advantage over the inhalation anesthetics. Among the four anesthetics tested, results were closest to the awake pattern with isoflurane anesthesia, thus making it the logical choice for hemodynamic studies in experimental shock research.