Abnormal ornithine decarboxylase activity in transgenic mice increases tumor formation and infertility.

A transgenic mouse line carrying ornithine decarboxylase cDNA as the transgene under the control of a mouse mammary tumor virus long terminal repeat (MMTV LTR) promoter was generated in order to study whether ornithine decarboxylase transgene expression will have any physiological or pathological effect during the entire life of a transgenic mouse. The high frequency of infertile animals and the loss of pups made the breeding of homozygous mice unsuccessful. However, a colony of heterozygous transgenic mice was followed for 2 years. In adult heterozygous transgenic mice, ornithine decarboxylase activity was significantly increased in the testis, seminal vesicle and preputial gland when compared to non-transgenic controls. In contrast, ornithine decarboxylase activity was decreased in the kidney and prostate of transgenic mice. No significant changes in ornithine decarboxylase activity were found in the ovary and mammary gland and only moderate changes in ornithine decarboxylase activity were detected in the heart, brain, pancreas and lung. The most common abnormalities found in adult animals (12 males and 20 females) of the transgenic line were inflammatory processes, including pancreatitis, hepatitis, sialoadenitis and pyelonephritis. Spontaneous tumors were observed in eight animals, including two benign tumors (one dermatofibroma, one liver hemangioma) and six malignant tumors (one lymphoma, one intestinal and three mammary adenocarcinomas and one adenocarcinoma in the lung). No significant pathological changes were found in 17 nontransgenic controls.

The effects of early mobilisation and immobilisation on the healing process following muscle injuries.

The biological processes following muscle injury include 2 competitive events; regeneration of muscle fibres and the simultaneous production of granulation tissue. We have studied the effects of early mobilisation and immobilisation on the healing of rat gastrocnemius muscle following partial rupture by a controlled contusion mechanism. Muscle fibre regeneration is inhibited by the formation of dense connective tissue scar. Immobilisation following injury limits the size of the connective tissue area formed within the site of injury; the penetration of muscle fibres through the connective tissue is prominent but their orientation is complex and not parallel with the uninjured muscle fibres. Immobilisation for longer than 1 week is followed by marked atrophy of the injured gastrocnemius muscle. Mobilisation started immediately after injury is followed by a dense scar formation in the injury area prohibiting muscle regeneration. When mobilisation is started after a short period of immobilisation a better penetration of muscle fibre through the connective tissue is found and the orientation of regenerated muscle fibres is aligned with the uninjured muscle fibres. Although a little delay in healing processes in muscles mobilised after short immobilisation was found morphologically, the gain in strength and energy absorption capacity was quite similar and as good as that of muscles treated by early mobilisation alone.

Chronic Achilles paratenonitis in athletes: a histological and histochemical study.

Pathological alterations of chronic Achilles paratenonitis were studied histologically and histochemically in tissue samples obtained operatively from 16 athletes with this complaint and from 3 control patients. The activities of 11 different enzymes--lactate, succinate, malate, glucose-6-phosphate and glutamate dehydrogenases, lipoamide dehydrogenase and glutathione reductase (NADH2- and NADPH2-diaphorases), acid and alkaline phosphatases, phosphorylase and leucylaminopeptidase--were studied. Pathological findings were located diffusely around the tendon. A slight inflammatory cell reaction was found in all cases. The fatty areolar tissue was clearly thickened and edematous, and showed fibrinous exudations, widespread fat necrosis, considerable connective tissue proliferation and adhesion formation. The blood vessels showed profound degenerative and necrotizing changes. The thin membranes of the paratenon were clearly hypertrophied. Increased enzyme activities were mainly found in the fibroblasts, inflammatory cells and vascular walls. A moderate activity of lysosomal enzymes, an increased activity of enzymes of electron transport, anaerobic glycolysis, pentose phosphate shunt and decreased activity of those of aerobic energy metabolism were found. Simultaneously an increased amount of both neutral and acid mucopolysaccharides and a locally increased amount of elastic fibres were found in the inflamed paratenon. These results indicate that marked metabolic changes occur in paratenonitis, i.e. an increased catabolism and decreased oxygenation of the inflamed areas. The morphological alterations suggest that the gliding function of the paratenon may be impaired.

Classification of fractures of the tibial condyles.

We analysed 131 fractures of the tibial condyles in 130 patients, using a modification of the classification of Schatzker, McBroom and Bruce (1979). The patients were reviewed at an average of 7.6 years after the injury. Fifty-five (42%) fractures had been treated conservatively and 76 (58%) operatively. Medial unicondylar and medially tilted bicondylar fractures tended to redisplace into varus position and lateral unicondylar and laterally tilted bicondylar fractures into valgus. There were significant differences when the results were evaluated according to the methods of Hohl and Luck (1956) and Rasmussen (1973). Using our method in conservatively treated cases, the subjective results were acceptable in 49.1%, the functional results in 60.0% and the clinical results in 52.7%. In cases treated by operation the equivalent figures were 57.9%, 73.7% and 52.6%. The poorest results followed displaced medial condylar and medially tilted bicondylar fractures. Varus alignment of the tibial plateau was tolerated worse than valgus alignment.

Functional treatment of closed humeral shaft fractures.

We treated 93 consecutive patients, average age 53 (16-90) years, with closed humeral shaft fractures applying a functional brace immediately after injury. Seventy-two (77%) fractures healed without problems. There were significantly more consolidation problems in fractures in the proximal third (46% consolidated) compared to those at the middle (81% consolidated) and distal third (86% consolidated) of the shaft. Logistic regression analysis revealed the only predictive factor in respect to successful brace treatment was fracture location. No significant difference was found in respect to healing between different AO-type fractures.

Muscle injuries, their healing process and treatment.

Muscle injuries represent one of the most common traumas in sports medicine. They have different clinical manifestations depending on the trauma mechanism: laceration, contusion and strain. The range of lesions varies from minor partial ruptures to complete ruptures of the muscle. The muscular tissue has a capacity to regenerate and the healing process consists of regeneration of muscle fibres and formation of a connective tissue scar. The healing is also greatly dependent on the ingrowth of vascularity and regeneration of intramuscular nerve branches. Immobilization and mobilization have a notable impact on the recovery, the former being of importance initially by reducing the size of injury and the latter later on by inducing greater granulation tissue production. Mobilization treatment is also a prerequisite for intensive muscle fibre regeneration and better preconditions to achieve the original tensile properties of the muscle. Surgical intervention is occasionally needed in complete ruptures to evacuate the haematoma or to suture the ruptured ends of the muscle to apposition.

Effect of the position of immobilization upon the tensile properties of the rat gastrocnemius muscle.

This study compared the tensile properties of the atrophied gastrocnemius unit after immobilization in a shortened position (SP) and lengthened position (LP). The left hind legs of 52 male Wistar rats were fixed with plaster casts either with the knee in flexion and the ankle in extension, or vice versa. After seven to 21 days of immobilization the load-deformation curves and the weights of both gastrocnemius muscle-tendon units from each rat were evaluated. The initial length increased about 4% in the LP immobilized muscles and decreased about 5% in the SP immobilized muscles when compared to the contralateral controls. The decrease in force to failure averaged 21% in the LP and 31% in the SP immobilized muscles after one week and continued to about 26% and 48%, respectively, in three weeks. The corresponding elongation decreased 13% and 21% in one week and 17% and 36% at the end of the third week when immobilized in the LP and SP, respectively. The decrease in elastic stiffness was similar in both groups, but the loss of energy absorption capacity before failure was more prominent in SP fixed muscles (64%) than in LP fixed muscles (49%). The loss of weight of the muscle-tendon units due to the immobilization was greater in the SP (36%) than in the LP (12%). We conclude that immobilization of the rat gastrocnemius muscle-tendon unit in an SP is followed by a more marked muscle atrophy and a greater decrease in tensile properties than immobilization in an LP.

Isokinetic performance of the thigh muscles after tibial plateau fractures.

The isokinetic performance of thigh muscles was evaluated in 37 patients at an average of 7 years after sustaining a fracture of the tibial plateau. The mean torque deficit in the quadriceps of the injured limb was an average of 15% at a speed of 60 degrees/s and 16% at 180 degrees/s, while the corresponding deficits in the hamstrings were 3% and 8%. The radiological appearance of the injured knee correlated significantly to the quadriceps deficit at both speeds. Limited knee movement and thigh atrophy also correlated with the deficit at the lower speed. The strength deficit tended to decrease during follow-up. A multiple step-wise regression analysis showed that the radiological result, length of follow-up and thigh atrophy accounted for 47% of the variation in loss of quadriceps strength. At the higher speed, the functional result was associated with the deficit in quadriceps strength, and older patients had greater deficits than younger. Regression analysis indicated that the radiological and functional result accounted for 31% of the variation in quadriceps strength. Anatomical restoration of the tibial plateau and good muscle rehabilitation are important in obtaining good long term results after this fracture.

Treatment of low-energy tibial shaft fractures: plaster cast compared with intramedullary nailing.

We analyzed data from 87 patients who had displaced closed or open grade I simple or spiral wedge tibial shaft fractures caused by low-energy impact. Fifty-four patients were treated with plaster cast and 33 with intramedullary locking nail (IMLN). Delayed union only occurred in 8 patients after plaster cast treatment. Forty-two patients in the IMLN group and one in the plaster cast group suffered from anterior knee pain. Final treatment outcome, healing time, hospitalization time and duration of sick leave were assessed on the basis of 25 matched pairs of patients. Mean healing time, hospitalization time and sick leave in the plaster cast and IMLN groups were 19 (SD 6.7) and 12 (SD 4.4) weeks (P<0.001); 8 (SD 4.8) and 7 (SD 2.7) days (P=0.686); and 195 (SD 81) and 106 (SD 31) days (P=0.001), respectively. No difference was found between plaster cast and IMLN groups when the outcome was evaluated using the criteria of Johner and Wruhs.

Correlation of specific keratins with different types of epithelial differentiation: monoclonal antibody studies.

We have prepared three monoclonal antibodies against human epidermal keratins. These antibodies were highly specific for keratins and, in combination, recognized all major epidermal keratins of several mammalian species. We have used these antibodies to study the tissue distribution of epidermis-related keratins. In various mammalian epithelia, the antibodies recognized seven classes of keratins defined by their immunological reactivity and size. The 40, 46 and 52 kilodalton (kd) keratin classes were present in almost all epithelia; the 50 kd and 58 kd keratin classes were detected in all stratified squamous epithelia, but not in any simple epithelia; and the 56 kd and 65-67 kd keratin classes were unique to keratinized epidermis. Thus the expression of specific keratin classes appeared to correlate with different types of epithelial differentiation (simple versus stratified; keratinized versus nonkeratinized).

Which displaced spiral tibial shaft fractures can be managed conservatively?

The aim of the present study was to establish a threshold for the initial displacement of a spiral tibial shaft fracture beyond which its retention in an acceptable position cannot be guaranteed by plaster immobilization. We reviewed the records and radiographs of 131 plaster cast-treated patients with spiral tibial shaft fracture, initially displaced 50% or less, for patients whose fracture had either lost its acceptable retention or consolidated in an unacceptable position. The fractures were classified, according to the true initial displacement as measured on the first radiographs, into four pairs of categories using cut-off points of 10, 20, 30 and 40% of the diameter of the tibial diaphysis. Comparison was then made of the proportions of failed treatments between each of these pairs. Plaster cast treatments failed in 28% when the true initial displacement was 30% or less, and in 46% when the true initial displacement was more than 30%. The risk of failed plaster cast treatment increased when true initial displacement exceeded 30%. In all patients whose plaster cast treatment was interrupted the true initial displacement was more than 30%. We therefore conclude that diaphyseal fractures of the tibia for which the initial displacement exceeds 30% are not suitable for plaster cast treatment.

Cast treatment and intramedullary locking nailing for simple and spiral wedge tibial shaft fractures--a cost benefit analysis.

BACKGROUND AND AIMS: The aim of this retrospective study was to compare the relative costs of treating simple and spiral wedge (requiring closed reduction under anaesthesia) tibial shaft fractures in a plaster cast or with intramedullary locking nail. MATERIAL AND METHODS: The material consisted of 26 fractures treated in a plaster cast and 51 fractures treated with an intramedullary locking nail. The costs caused by the direct costs (treatment, hospitalisation, and outpatient appointments) as well as indirect costs (lost productivity) were taken into account. Costs caused by complications were also included in the analysis. RESULTS: Mean direct costs per patient were FIM 22920 and FIM 26952 and mean overall costs per patient were FIM 120486 and FIM 82224 in plaster cast and intramedullary locking nailing groups, respectively (FIM 1 = USD 0.19). The higher mean overall costs of the plaster cast group were attributable to the longer sick leave periods in this group (218 days in plaster cast group and 124 in intramedullary nailing group). CONCLUSION: Plaster cast treatment of simple and spiral wedge tibial shaft fractures requiring closed reduction under anaesthesia is more expensive to society than operative treatment with intramedullary locking nail.