Common regulation of feeding and mating in Aplysia fasciata: pheromones released by mating and by egg cordons increase feeding behavior

We examined whether pheromones released by reproductive behaviors (mating and egg-laying) affect feeding behavior. A preliminary experiment demonstrated that the quantity of food eaten can be used to measure the effects of pheromones on feeding. Using this measure, we then showed that Aplysia that were prevented from mating, but that were in the same aquarium as mating conspecifics, eat more food than do Aplysia in a medium lacking mating animals. Mating and feeding were not temporally correlated, indicating that pheromones released by mating probably do not initiate feeding, but rather modulate feeding after it has begun. Aplysia that were in the same aquarium as freshly deposited egg cordons also ate more than did animals in a medium lacking eggs.

Sequencing of behaviors in Aplysia fasciata: integration of feeding, reproduction, and locomotion

To begin studying the neural basis of higher-order decision-making in Aplysia fasciata, we examined individual bouts of behavior in various conditions of access to food and/or mates. We then determined rules governing transitions between bouts. The data indicate that a single intermediate condition, moving in place, may be centrally related to transitions between behaviors. In all conditions, over 85% of all transitions between behaviors were via moving in place. Moving in place tended to precede and follow other categories of activity (crawling, swimming, immobile), and feeding. Also, moving in place apparently represents a fixed proportion of all bouts of behavior. In each condition, moving in place represented approximately 40% of all bouts, while the number of bouts of other behaviors varied markedly. After a bout of moving in place there was a strong tendency for the animal to return to the behavior performed before moving in place. Additional preferred sequences of behavior were also seen. Courtship tended to precede mating, and crawling preceded swimming.

Oscillations of cortical oxidative metabolism and microcirculation in the ischaemic brain

A new in vivo model for studying brain metabolic and haemodynamic oscillatory phenomena during ischaemia is described. In this model acute or chronic occlusion of one or two carotid arteries in the rat is performed. Due to the partial ischaemia developed, oscillations in the level of intramitochondrial pyridine nucleotides (NADH) as well as flavoproteins (Fp) were recorded from the brain by monitoring the fluorescence of these respiratory chain components. The two fluorescent signals (NADH and Fp) were measured by using the time sharing or DC fluorometer/reflectometer. The changes in the reflected light at the excitation wavelengths (366 and 450 nm) were recorded simultaneously. Bilateral carotid artery occlusion induced immediate oscillations (6-9 waves per min) in the mitochondrial redox state as well as in tissue blood volume in both hemispheres. To verify the accuracy of the NADH monitoring system, including the correction technique for haemodynamic and other artifacts, we used the intracarotid artery saline bolus injection approach. The results could be summarized as follows: (1) unilateral carotid artery occlusion resulted in delayed development of oscillations, particularly in the ipsilateral hemisphere; (2) the oscillation phenomenon was reversible if recirculation restarted within 5 min. Occlusion for more than 30 min resulted in irreversible oscillations; (3) the oscillation appearances and intensities were affected by various physiological conditions. Vasoconstriction, induced by hyperoxia, stimulated the oscillations while vasodilation, induced by hypercapnia, depressed them. Anoxia, hypoxia and spreading depression (SD) abolished the oscillations. Glucose injection was not effective.(ABSTRACT TRUNCATED AT 250 WORDS)

Daily variation of multiple behaviors in Aplysia fasciata: integration of feeding, reproduction, and locomotion

Daily variations in feeding, reproductive behaviors, and activity level were examined under three conditions: (1) animals had access to food and mates; (2) there was access only to food; (3) neither food nor mates were present. Behaviors differed in amplitude of variations from their daily mean value. Egg-laying had the strongest tendency to be clustered. Amplitude of variations in courtship and swimming was larger than those of immobility, crawling, and feeding, while moving in place was the least clustered behavior. Changes in state affected the tendency to be clustered. When food and mates were present, amplitude of variations became progressively larger for immobility, moving in place, crawling, and swimming. Behaviors differed in the degree to which variations were patterned as a 1/day oscillation. Relatively little of the variability in crawling, moving in place, courtship, and egg-laying was due to a 1/day oscillation under any condition. By contrast, a large proportion of the variability of immobility, swimming, mating, and eating was modulated by a 1/day oscillation in at least one condition. The contribution of a 1/day oscillation to variability differed in the conditions examined. For immobility and swimming, when food and mates were present, the 1/day component of variability became smaller. By contrast, presence of mates led to an increase in the 1/day component of variability modulating feeding. Daily peaks of swimming and feeding were in phase with one another, and out of phase with mating and feeding. The ratio of locomotion to inactivity is constant, independent of change in external conditions. However, this ratio varied throughout the day. When food and mates were absent, variations of immobility and swimming were strongly related to variations in the inactivity ratio. When food and mates were added, this tendency decreased. The data suggest that daily variations in occurrence of behaviors can be accounted for by interactions between oscillators affecting Aplysia behavior and motivational variables. A 1/day oscillator has strong effects on mating, swimming, and immobility. The effect of the oscillator is modified by changes in motivational state.

Effects of conspecifics on feeding in Aplysia fasciata

The presence of other Aplysia in the environment increases the time spent feeding. This finding is consistent with the hypothesis that a common arousal mechanism modulates feeding and reproductive behaviors. The arousal level is presumably increased by pheromones released by additional animals.

Osteoid osteoma of the scapula. A case report and review of the literature

The scapula is a rare location for osteoid osteoma, which in most cases does not involve the flat bones. The en bloc excision in this uncommon location can be problematic since the surgical exposure is difficult, and shoulder joint function can be affected if the lesion is subchondral. In an 18-year-old man, an osteoid osteoma was located in the subchondral area of the glenoid. A guided needle biopsy of the nidus resulted in complete healing. This mode of treatment, with proper follow-up examination, is acceptable for a benign lesion situated in a problematic location.

Effects of food and mates on time budget in Aplysia fasciata: integration of feeding, reproduction, and locomotion

This study examines the time budgeted to different behaviors in Aplysia fasciata under three conditions: (1) animals have constant access to food and mates: (2) there is access to food, but not to mates; (3) neither food nor mates are present. The data suggest a number of rules underlying behavioral integration: (1) Feeding, reproductive behaviors, and activity seem to be natural categories for behavioral choice. Feeding and reproductive behaviors are controlled in tandem by a common arousal mechanism, while time left over after animals feed and reproduce is distributed in a fixed ratio between locomotion (crawling and swimming) and inactivity (immobility and movement in place). (2) Relative distribution between different forms of locomotion and inactivity is modified by changes in motivational state. More time is spent swimming than crawling when feeding and/or mating is prevented, while more time is spent moving in place than immobile when the arousal level is increased. (3) Feedback control of feeding and reproduction is asymmetric. Satiation of feeding inhibits the common arousal. In the absence of food, time spent on reproductive behaviors increases due to disinhibition of the common arousal. By contrast, positive feedback arising from sexual behavior excites the common arousal. When mating is prevented by removing potential mates, time spent feeding decreases. (4) Generally, animals choose between performing the three main categories of behavior. Although Aplysia simultaneously can feed and mate, or locomote and mate, they do so infrequently. By contrast, different types of reproductive behaviors (male mating, female mating, egg-laying) are commonly performed simultaneously.

Immediate care of crush injuries and compartment syndromes with the split-thickness skin excision

Prospective evaluation of the one-stage procedure in 32 patients who suffered from 37 severe friction-avulsion injuries was carried out. Most injuries (81%) were in the lower extremity. Split-thickness skin excision was used for immediate diagnosis of flap vascularity and wound coverage. Split-thickness skin was harvested from the avulsed flap surfaces after they were temporarily sutured back to their original bed. Dermal capillary bleeding served as an indicator for tissue viability, thus delineating a clear line for debridement. All compartments were decompressed, and debridement of all devascularized tissues was performed. Most fractures were fixed with interfragmentary screws and external fixators. Viable parts of the avulsed flaps were sutured back to their original bed and exposed bones were covered with transposed muscles. Skin defects were grafted with the split-thickness skin that was harvested in the first stage and was meshed 1:3 to allow drainage. Most patients (26 out of 32) had only one surgical procedure for their extensive injuries. The split-thickness skin excision is effective in the establishment of debridement borders and helps in saving maximal viable flap area (49.4%). All wounds healed with no major wound complications. The split-thickness skin excision can be used immediately in the care of severe crush injuries, compartment syndromes, and open fractures as a one-stage procedure with the following advantages: (1) reliable diagnosis of flap vascularity, (2) immediate wound coverage with the possibility of drainage, (3) elimination of further debridements procedures, (4) elimination of distant skin donor wounds, and (5) less hospitalization.

Spondylosis in sand rats: a model of intervertebral disc degeneration and hyperostosis

This study defines gross, histopathologic, and radiologic changes associated with intervertebral disc degeneration in a spontaneously occurring form of the disease in aging sand rats (Psammomys obesus). Sand rats (male/female) fed lab chow supplemented with desert salt bush were sacrificed at periods of 3-30 months. Lateral thoracolumbar spine films were obtained. At sacrifice, spines were surgically exposed and gross findings were recorded; after fixation/decalcification, histopathologic studies were carried out using hematoxylin and eosin, and Safranin-O with fast green counterstain. Metabolic studies included correlations of pathologic and radiologic findings with blood glucose and insulin levels. Disc-space narrowing and subchondral endplate sclerosis increased radiologically with age, with more severe lower lumbar disc lesions. Ligamentous calcifications ventral to involved discs and caudal vertebrae were common. Disc thinning and anterior vertebral bony/cartilaginous spurs were more marked with age. Microscopy revealed loss of nucleus pulposus physaliform cells, chondrocyte replication, disc necrosis, and ossification. Hyperglycemia with and without hyperinsulinemia was common. No statistically significant differences in pathologic findings were noted, neither in diabetic versus nondiabetic nor in hyperinsulinemic animals. The sand rat is a model of disc degeneration; similarities with possible overlap with diffuse idiopathic skeletal hyperostosis syndrome were noted.

Motivational control of sexual behavior in Aplysia fasciata: sequencing and modulation by sexual deprivation and by addition of partners

Variables similar to those affecting feeding behavior also modulate sexual behavior in Aplysia fasciata, indicating that mating is under motivational control. Motivated behaviors are often patterned into appetitive and consummatory components. Courtship, the appetitive phase of male sexual behavior, was temporally related to subsequent mating. Although many bouts of courtship failed to lead to mating, most incidents of mating were preceded by courtship. Motivation is also characterized by satiation after the goal of the behavior is achieved. We found an increase in likelihood to mate following a period of sexual isolation. Motivated behaviors are also modulated by environmental stimuli that induce arousal. Time spent mating was found to be a function of the number of potential mates accessible for mating. Number of A. fascinata participating in a mating group was also found to be a function of number of potential mates available.

One-stage treatment of gunshot wounds

Delayed primary closure has been advocated for the treatment of gunshot wounds owing to the fact that they are highly contaminated. The authors believe that with meticulous debridement, contaminants are removed; thus, early wound coverage with meshed split-thickness skin graft allows for drainage along with faster healing of all tissues. Split-thickness skin excision was found to be a useful procedure in the immediate management of gunshot injuries.

Crush injuries of the foot with compartment syndrome: immediate one-stage management

Severe crush injuries with compartment syndrome were treated in five patients by an immediate one-stage procedure. This procedure included the assessment of skin flap viability with accurate debridement of devascularized tissues. It was performed according to the split-thickness skin excision technique. Compartment pressures were measured and the fasciotomies were performed through open wounds or separate medial and lateral incisions. The medial incision was extended to release the tarsal tunnel. Fractures were reduced and internally fixed and exposed bones were covered with locally transposed muscles. Skin grafts, taken earlier for the skin viability assessment, were meshed and applied to replace skin loss. All wounds and fractures healed uneventfully with no major functional loss. In multiple trauma, the physician should maintain a high index of suspicion for early diagnosis and treatment of severe foot injuries. Early treatment leads to more desirable results, shorter hospitalization, and faster rehabilitation.

Osteogenesis in in vivo diffusion chamber cultures of human marrow cells

The osteogenic diffusion chamber culture of rodent marrow cells is a well established system. In the present study, marrow cells from children and adult human donors were incubated in diffusion chambers implanted intraperitoneally in athymic mice. After 4 or 8 weeks, the chamber content was examined by light and electron microscopy. Child-cell cultures showed osteogenic tissue consisting of a mineralizing fibrous component and cartilage. Ultrastructurally, the fibrous tissue was similar to osteoid and exhibited osteoblast-like cells and mineralizing nodules. Mineral aggregates were also found in the cartilage. These features in child-cell chambers were similar to those found in control chambers of rabbit marrow cells. Adult-cell chambers showed only unmineralized fibrous tissue. These results render previous findings in animal-cell diffusion chamber systems relevant to the understanding of bone formation in man. It is suggested that the difference between child- and adult-cell chambers reflects an age-related decline in the number of marrow osteoprogenitor cells or their potential to undergo terminal osteogenic differentiation.

Cervical instability in an achondroplastic infant

Cervical spine instability is a rare finding in achondroplasia. We present the previously unreported case of C2-C3 subluxation producing progressive quadriparesis in an achondroplastic infant. Operative treatment with appropriate fusion was performed, and an excellent result was obtained.

Cultured human bone marrow-derived mast cells, their similarities to cultured murine E-mast cells

Homogeneous populations of human mast cells were differentiated and grown by culturing bone marrow cells in the presence of conditioned medium derived from lectin-stimulated human peripheral blood mononuclear cells. The cells obtained were similar in ultrastructure, proteoglycan type and lipid products generated upon calcium ionophore A23187, and immunological activation to the murine E-mast cells (E-MC) differentiated in culture containing IL-3. Fluorescence analysis revealed that the human E-MC expressed IgE-Fc receptors which retained bound IgE through several washes. These cells did not express cell-surface lymphoid determinants (T11, T4, T8 and B4) and myeloid determinants 'My'. However, 40% of these cells expressed monocytic surface determinants, such as M-1. The amount of histamine that was found per 10(6) cells was 525 +/- 106 ng (mean +/- SE, n = 4). These cultured mast cells possessed granular chondroitin sulphate E proteoglycan of about 180,000 MW. Following activation with either calcium ionophore A23187 or anti-hIgE challenge, these mast cells released their preformed mediators and generated mainly leukotriene C4 leukotriene B4, and platelet-activating factor. In conclusion, according to all of these criteria, these human cultured mast cells show many similarities to the murine cultured E-mast cells, and therefore could be considered as the culture analogue of the human intestinal E-mast cells identified recently.

Split-thickness skin excision in severe open fractures

Split-thickness skin excision can be used as a one-stage procedure for the accurate diagnosis of flap viability and the immediate treatment of friction-avulsion injuries in severe open fractures. After cleaning the wound, the avulsed flap is temporarily sutured back to its original bed and a split thickness graft is taken from it and meshed to a 1:3 ratio. Surface dermal capillary bleeding then serves as an indicator of viability, clearly displaying a line for the excision of devascularized skin and correlating well with a concomitant fluorescein test. The wounds are re-opened and, after fixation of the fracture, the viable part of the flap is returned to its original bed and the remaining defects are covered with the meshed graft. We have treated 16 patients with extensive degloving injuries in this way, 15 needing only the single surgical procedure. All retained flaps survived, no other donor sites were needed and the split-thickness grafts took with 90% to 100% success.

Spondylolysis in the upper lumbar spine. A study of 32 patients

Reports of spondylolysis in vertebrae other than those of the lower lumbar spine are rare. We report 32 patients with upper lumbar spondylolysis who have been studied clinically, radiologically and scintigraphically. Twenty patients had bilateral lesions, and seven of those with unilateral lesions had structural changes or anomalies in the opposite posterior arch. Positive scans were found to be associated with a short clinical history, and indicated stress-related lesions. Our findings suggest that mechanical factors may play a role in the aetiology of spondylolysis in the upper lumbar spine similar to that which they play in the lower lumbar spine, and that local structural anomalies may contribute to abnormal loading of these vertebrae.

How to harvest skin graft from the avulsed flap in degloving injuries

A new and simple way of harvesting skin graft from a degloved flap is presented. This technique allows precise harvesting and does not require assistance. The split-thickness skin excision is also a reliable diagnostic tool for determining degloved flap avascularity.

Unusual combination of Monteggia, Colles', and navicular fractures

A rare combination of an ulnar fracture with posterior dislocation of the head of the radius and intraarticular fracture of the distal radius concomitant with an ipsilateral navicular fracture is presented. To the best of our knowledge, no such case has been reported. The mechanism of this fracture combination is discussed with respect to its role in producing the Monteggia type II fracture. Treatment consisted of a combination of closed and open reduction with external fixation.

The "instantaneous" deformation of cartilage: effects of collagen fiber orientation and osmotic stress

The present study was undertaken with two objectives in view. The first was to distinguish between the "instantaneous" deformation and creep of articular cartilage when subjected to a step loading in unconfined compression. This was done by observing changes in the specimen's diameter rather than its thickness. The second objective was to investigate experimentally the anisotropic behaviour of cartilage in a compressive loading mode, corresponding to the physiological situation. An apparatus was thus developed and constructed which enabled us to follow the "instantaneous" changes of the surface area of the sample as the latter was being loaded in unconfined compression. Specimens of human articular cartilage from normal femoral heads and condyles were tested. Full thickness specimens were tested with and without the underlying bone, as well as partial thickness specimens, characterizing the different zones of cartilage. Solutions of different ionic strength were used to vary the osmotic stress and specimens covering a considerable range of proteoglycan concentrations were selected. The effects of hydration and proteoglycan removal on the "instantaneous" deformation were also studied. The "instantaneous" deformation was found to be of a strongly anisotropic nature in all zones. The deformation was always smaller along the Indian-ink prick pattern than at 90 degrees to it, and this effect was most pronounced in the superficial zone of cartilage. The results reveal an analogy with the tensile properties of cartilage and indicate that the collagen network is mainly responsible for controlling the "instantaneous" deformation. The proteoglycans play an indirect role by modulating the stiffness of the collagen network through their osmotic pressure.

Studies of hydration and swelling pressure in normal and osteoarthritic cartilage

An experimental study was carried out which involved comparing cartilage from normal and osteoarthritic joints with respect to (a) swelling pressure and (b) variation of hydration with applied pressure. The main conclusion was that whilst osteoarthritic cartilage is undoubtedly less able to resist water loss under a given applied pressure than normal cartilage, this is not due to a change in the "quality" of the proteoglycans, resulting in a change in the osmotic pressure of the latter, but simply to a decreased fixed charge density. The latter decrease is either caused by an increase in the water content - and this we attribute to a weakened collagen network - and/or to a loss of part of the proteoglycans from the tissue.

Roll-over test--errors in interpretation, due to inaccurate blood pressure measurements

In order to make the earliest possible prediction of the type of woman likely to develop pregnancy-induced hypertension (PIH), one hundred and ninety-six primigravidas underwent a roll-over test (ROT) during wk 28-32 of their pregnancy. Blood pressure (BP) readings were taken with a standard 12 cm cuff as well as with cuffs adapted to various arm circumferences. We found that the prediction rate of ROT readings with a standard 12 cm cuff was relatively low (38.5%) as compared with Gant's study (94%) (Amer. J. Obstet. Gynec., 120 (1974) 1). When a suitably sized cuff was used, the prediction rate dropped (to 14.7%). Data analysis at term for the whole population of this study shows that, by measuring with a standard 12 cm cuff, 10.2% of the women were found to have PIH, whereas measuring with a suitable cuff showed PIH in only 2.55% of the cases (1:4 ratio). We suggest that the low prediction rates in this and other studies demonstrate that the ROT test is not sufficiently reliable as a tool for predicting which women are liable to develop PIH, but there is definitely enough in it to predict which group will not develop PIH (in this study 89-93%). It has been recommended that ROT be considered only as a test of possible reliability. It should be done according to proper criteria for BP measuring, and a repeat ROT should be considered after several days before starting any kind of treatment.

Correction of the malunited forearm fracture

Malunion of a child's forearm fracture is a functional and cosmetic disability. Drill osteoclasis is an alternative to open osteotomy. Fifteen consecutive cases demonstrate the following advantages of the technique: (1) the absence of an unsightly scar, (2) full, reliable correction of the deformity, (3) no need for a second operation to remove a plate, and (4) no risk of fracture occurring subsequently through a screw hole.

Femoral intramedullary nailing in the growing child

The outcome of intramedullary nailing in 17 femoral fractures was studied in children aged 5 to 12 years. By this age independent vascularity of the capital femoral epiphysis has become established. Indications were: severely displaced diaphyseal fractures uncontrolled by closed reduction in patients with head injury or multiple trauma. All were treated by open reduction and retrograde nailing using Rush pins or Kuntscher nails. All children became community ambulators and were followed until maturity. There were no significant rotational deformities and leg length discrepancy due to overgrowth was less than 1.0 cm at termination of growth. Growth arrest of the greater trochanter was seen in three hips that were reamed for Kuntscher nailing but in none of those fixed with Rush pins. Retrograde Rush pinning appears to be a safe and effective procedure that avoids insult to the proximal femoral blood supply. Growth plate changes did not significantly affect hip function.

Muscle growth in normal and spastic mice

Longitudinal muscle growth was studied in normal and spastic mice. Muscle growth takes place at the musculotendinous junction--the 'muscle growth-plate'. In spastic mice muscle growth is reduced by 45 per cent, resulting in contractures.

Treatment of femoral fracture in the child with head injury

The outcome of various types of treatment for femoral fracture in children with head injury was studied retrospectively in 51 patients with 56 fractures. Of these, 36 patients (71 per cent) were in deep coma and scored 5 to 7 on the Glasgow scale. Forty-three children (84 per cent) were eventually able to walk freely. Open reduction and internal fixation proved an attractive solution for femoral fractures in children with head injury who could tolerate general anaesthesia: intramedullary nailing was safe and gave satisfactory results in 16 fractures but infection complicated three of the five fractures which were plated.

Paraplegia in osteogenesis imperfecta. A case report

Paraplegia occurred in an adolescent girl with osteogenesis imperfecta after chiropractic manipulation. The child had been able to walk freely out of doors. Complete motor paralysis with sensory sparing resulted due to anterior compression of the cord by spondyloptotic cervical vertebrae. Reconstructed computerised tomography was very helpful in demonstrating the abnormality. Anterior and then posterior decompression relieved the tethered spinal cord and were supplemented with bone grafting. Early diagnosis and surgical treatment will prevent similar neurological accidents.

The importance of cuff width in measurement of blood pressure in pregnancy

Blood pressure was measured indirectly in 218 normotensive primigravidas with arm circumferences ranging from 21.7 to 36.1 cm using three standard blood pressure cuffs. It was found that the medical profession's lack of awareness as to the proper use of cuffs in prenatal care may involve 40% of the patients--20% of these have a small arm circumference, will not show a true blood pressure reading, and may fail to get the proper treatment. On the other hand, 20% of these patients who have a rather large arm circumference, may be grouped among those who need special care and attention, and may be given unnecessary treatment--a fact which may bring about clinical complications, unnecessary expense, incorrect statistical data and a misleading demographic impact.

The role of arthroscopy in children

The records for 156 consecutive arthroscopic examinations in children with knee complaints were reviewed. Diagnostic accuracy was based on subsequent arthrotomy and the clinical course in the absence of arthrotomy. All arthroscopies were performed by one person (NCC) between 1975 and 1979. Children under 12 years (most of them aged 6-11 years) accounted for 43 of the patients. The arthroscopic diagnoses were classified into three categories: very useful, useful, and not useful. Arthroscopy was found to be very useful in 30% of children in both age groups, those under and those over 12 years. In all these patients, unnecessary arthrotomies were avoided. Most (63%) of the arthroscopies were found to be useful, since they provided additional findings and biopsies. Only in 5% of cases did the arthroscopy fail to add any information. There were no complications from the procedure. Arthroscopy is an effective diagnostic tool that can be used safely in children.

Orthotopic bone transplantation in mice. II. Studies of the alloantibody response

The alloantibody response of mice receiving cortical bone allografts was investigated. Such grafts were highly immunogenic, resulting in antibody responses at least as strong as those to skin allografts in the same combinations. The duration of the response to a single bone allograft was very prolonged (greater than 10 months). The antibody response was shown to be directed against H-2K, H-2D, Ia, and at least two non-H-2 antigens. Although the great majority of the parenchymal cells of the graft were dead, the immunogenicity of the graft required living cells, since bone that had previously been frozen and thawed was nonimmunogenic. By retransplanting bone allografts to a second recipient it was possible to demonstrate that the grafts remained immunogenic for at least 4 weeks after transplantation, indicating that the living immunogenic cells survived in the recipient for at least 4 weeks. Such cells may be certain cells of the cortical bone itself, or else residual bone marrow elements which adhere to the endosteal surface of the bone. The observation that a small subpopulation of living cells can provoke strong immune responses against a wide variety of antigens may have implications for understanding the immunogenicity of other types of allografts.

Orthotopic bone transplantation in mice. I. Technique and assessment of healing

A technique for orthotopic bone transplantation in mice has been developed. A section of recipient tibia was removed and replaced by a similar section from the donor animal. The graft was held in place by internal fixation. Bone healing was assessed clinically, histologically, radiologically, and by torsion testing. The most objective measurements of bone healing were the maximum torque and the energy absorbed by the bone to failure, which were derived from torsion testing. The degree of bone healing in donor-recipient combinations differing at H-2, non-H-2, or H-Y antigens was compared to the degree of healing in syngeneic controls. The incidence of nonunion was significantly increased in the H-2-disparate group. Furthermore, the extent of bone healing as measured by torsion testing was significantly reduced in both the H-2-and the H-Y-disparate groups. Thus, in the strain combinations tested, the order of importance of the genetic disparities influencing allogeneic bone grafts was H-2 greater than H-Y greater than non-H-2. The impaired healing of allogeneic bone grafts was probably immunologically mediated, as suggested by the observation that recipients of bone allografts rejected subsequent skin allografts in an accelerated manner.