Three-dimensional simulation of clouds of multi-disperse evaporating saliva droplets in a train cabin.

In line with recent ongoing efforts to collect crucial information about the mechanisms of virus diffusion and put them in relation to the effective complexity of the several natural or artificial environments where human beings leave and operate, the present study deals with the dispersion of evaporating saliva droplets in the cabin of an interregional train. A relevant physical model is constructed taking into account the state of the art in terms of existing paradigms and their ability to represent some fundamental aspects related to the evolution in time of a cloud of multi-disperse droplets. Conveniently, such a theoretical framework is turned into a computational one that relies on low Mach-number asymptotics and can therefore take advantage of the typical benefits (relatively low computational cost) associated with pressure-based methods. Numerical simulations are used to predict the flow established in the cabin as a result of the ventilation systems and related settings dictated by considerations on passenger comfort. The solution of two-way coupled Lagrangian evolution equations is used to capture the associated dynamics of the dispersed phase and predict its transport in conjunction with the peculiar topology of the considered flow and morphology of solid surfaces, which bound it (including the human beings). Typical physiological processes such as talking or coughing are considered. An analysis on the impact of the multiplicity of droplet sources is also conducted, thereby providing some indications in terms of potential risks for the cabin occupants.

Vascularized bone marrow transplantation model in rats as an alternative to conventional cellular bone marrow transplantation: preliminary results.

The aim of the study was to follow the development of microchimerism after allogeneic vascularized bone marrow transplantation (VBMT) versus conventional bone marrow transplantation (BMT). In one group, a VBMT model consisted of donor Brown Norway rat hind limb heterotopic transplanted on recipient Lewis rats. An intravenous infusion of donor bone marrow cells in suspension equivalent to that grafted in the vascularized femur limb was administered intravenously to recipient rats in the second group. Cellular microchimerism was investigated in recipients of VBMT versus BMT. Donor-derived cells could be detected in VBMT recipients at 30 and 60 days but not in recipients of intravenous suspension of BMC. VBMT provides a theoretical alternative to conventional cellular bone marrow transplantation by addressing crucial clinical problems such as failure of engraftment or graft-versus-host disease.

Long-term follow-up in composite tissue allotransplantation: in-depth study of five (hand and face) recipients.

Composite tissue allotransplantations (CTAs) have clinically shown little, if any, evidence of chronic rejection. Consequently, the effect of chronic rejection on bones, joints, nerves, muscles, tendons and vessels may still have undescribed implications. We thoroughly assessed all allograft structures by histology, magnetic resonance imaging, ultrasonography and high resolution peripheral quantitative computed tomography scan in four bilateral hand-grafted patients (10, 7, 3 and 2 years of follow-up, respectively) and in one facial allotransplantation (5 years of follow-up). All the recipients presented normal skin structure without dermal fibrosis. Vessels were patent, without thrombosis, stenosis or intimal hyperplasia. Tendons and nerves were also normal; muscles showed some changes, such as a variable degree of muscular hypotrophy, particularly of intrinsic muscles, accompanied by fatty degeneration that might be related to denervation. In the majority of hand-grafted patients graft radius and recipient tibia showed a decrease in trabecular density, although in the graft radius the alterations also involved the cortices. No deterioration of graft function was noted. In these cases of CTA no signs of chronic graft rejection have been detected. However, the possibility that chronic rejection may develop in CTA exists, highlighting the necessity of close continuous follow-up of the patients.

Sentinel skin allograft-a reliable marker for monitoring of composite tissue transplant rejection.

Previous studies have demonstrated that composite tissue transplants such as limbs reject more slowly than skin transplants. This has led to the hypothesis that a simultaneous skin graft may act as an effective marker of limb rejection. The aim of this study was to test the predictive value of a sentinel skin graft as a marker of rejection, using a hind limb transplantation model in rats. Lewis rat recipients received hind limb transplants alone from a Brown Norway donor (control; n = 15) or combined with a full-thickness 15 cm(2) sentinel skin graft (n = 45). All animals received drug therapy (tacrolimus, mycophenolate mofetil, and prednisone) for 6 weeks; then, treatment was ceased entirely. Rejection of the skin graft and limb skin was assessed both by visual and histologic grading systems. Detectable visual rejection (grade 1) was observed earlier in the sentinel skin graft than in the limb skin (P < .0005); the clearest visual rejection (grade 2) appeared earlier in the sentinel skin graft (P < .005). The average histologic grade for early rejection of the skin graft was 1.46 and 1.08 for the limb skin (P < .05). These findings confirmed a visual and histologic delay in the rejection of limb skin compared with a distant sentinel skin graft. Skin grafts transplanted simultaneously with hind limbs may be a useful marker of early rejection.

Health technology assessment of a homecare device for telemonitoring and telerehabilitation for patients after hand transplantation.

Hand rehabilitation requires continuous and frequent monitoring of the functionality in order to assess therapy and/or refine it. In order to contain costs for the rehabilitation program, a telehomecare rehabilitation system is suitable. The purpose of this paper was to describe the setup and configuration of a homecare device for telemonitoring/telerehabilitation of patients who underwent hand transplant. The telehomecare device allows the assessment of dynamics and kinematics of hand function by integrating dedicated software in two components. The first was a commercial glove, the HumanGlove by Humanware (Pisa, Italy). The second was a set of instruments for the measurement of digit force using an Instrumented Keyboard and an Instrumented Mouse-Like device. The software integrating the devices is composed of two modular components. The first is to drive the devices; the second is for the data-analysis and display. The methodology was validated at the Istituto Superiore di Sanit (the Italian National Institute of Health) in the framework of an Italian National Project, funded by the Ministry of Health.

Atypical acute rejection after hand transplantation.

Skin rejection after hand transplantation is characterized by a maculopapular erythematous rash that may be diffuse, patchy or focal, and distributed over forearms and dorsum of the hands. This 'classical' pattern of rejection usually spares the skin of the palm and does not affect the nails. Herein, we report the experience on four cases presenting with an 'atypical' pattern of rejection that is novel in involving the palmar skin and the nails. All patients were young and exposed to repetitive and persistent mechanical stress of the palm. Characteristic features of rejection included a desquamative rash associated with dry skin, red papules, scaling and lichenification localized to the palm. Skin lesions were associated with nail dystrophy, degeneration, deformation or loss. Histology of the skin and nail bed revealed a lymphocytic infiltrate with predominance of T cells (CD3+, CD4+ and CD8+), with small numbers of B cells (CD20+ and CD79a+) and a low number of Forkhead transcription factor 3 (FOXP3)-positive cells in one patient. The lesions persisted over weeks to months, responded poorly to steroid treatment and were managed with antithymocyte globulin (ATG; Thymoglobulin, Genzyme, Cambridge, MA), alemtuzumab and/or intensified maintenance immunosuppression.

Bilateral hand transplantation: six years after the first case.

In this study we present our experience concerning bilateral hand transplantation. Two cases were performed: the first in January 2000 and the second in April 2003. Both recipients received the same immunosuppressive treatment, which was similar to those used in solid organ transplantation, including tacrolimus, prednisone and mycophenolate mofetil while antithymocyte globulins were added for induction. Both recipients presented two episodes of acute rejection (maculopapular lesions) in the first 3 months after transplantation; however, these were easily reversed after a few days increasing oral steroid doses and using topical immunosuppressants. The first recipient presented hyperglycemia and serum sickness while the second recipient suffered a thrombosis of the right ulnar artery and an osteomyelitis of left ulna. All the complications were successfully treated. Functional Magnetic Resonance Imaging (fMRI) showed that cortical hand representation progressively shifted from the lateral to the medial region in the motor cortex. After 6 and 2 years respectively, they showed a relevant sensorimotor recovery particularly of sensibility and activity of intrinsic muscles. They were able to perform the majority of daily activities and to lead a normal social life. The first recipient has been working since 2003. They are both satisfied with their grafted hands.

Donor leukocytes combine with immunosuppressive drug therapy to prolong limb allograft survival.

Donor leukocytes administered at the time of transplantation may prolong organ allograft survival. This study examined the effectiveness of donor leukocyte injection combined with immunosuppression for limb transplantation across the strong histocompatibility barrier of a Brown Norway donor to a Lewis recipient. Eight animals received 6 x 10(7) donor leukocytes injected on the day of transplantation. From day 1, FK506 (2 mg/kg/d), mycophenolate mofetil (MMF) (15 mg/kg/d), and prednisone (0.5 mg/kg/d) were administered for 2 weeks. After week 2, prednisone and MMF were both tapered by 20% of the initial dosage per week. After week 7, the animals received only FK506 (2 mg/kg/d). From week 8, FK506 was tapered to the maintenance dose of 0.8 mg/kg/d at week 10 and was stopped on week 24. A control group of 8 animals underwent identical treatment except that the leukocyte injection was omitted. Rejection was observed in both groups during FK506 monotherapy; however, the onset of early rejection episodes was significantly later, the period for reversal of the first rejection was significantly shorter, and the dosage of FK506 at the time of rejection was significantly lower among leukocyte-treated recipients. After completion of immunosuppression, survival was modestly prolonged in the leukocyte-treated group. One animal is surviving without immunosuppression on day 234. This trial of donor leukocyte injection combined with immunosuppression in limb transplantation showed a modest, but significant, improvement in outcome.

Donor leukocytes combined with delayed immunosupressive drug therapy prolong limb allograft survival.

Donor leukocytes administered at the time of transplantation may prolong organ allograft survival. Delayed administration of calcineurin inhibitors, such as FK506 or cyclosporine, may enhance their efficacy. Herein the effectiveness of this strategy to promote limb transplant survival was investigated in the strong histocompatibility barrier of Brown-Norway donor to Lewis recipients. Donor leukocytes (6 x 10(7) intravenously) were injected on the day of transplantation followed on day 1 to 14 with mycophenolate mofetil (MMF; 15 mg/kg/d) and prednisone, (0.5 mg/kg/d) which were then tapered by 20% each week and stopped at week 7. Administration of of FK506 (2 mg/kg/d) was started on day 4 and continued for 8 weeks, then tapered for 4 weeks to a maintenance dose of 0.8 mg/kg/d, which was continued for 12 weeks (group A; n = 8). A control group (n = 8) underwent identical treatment save for donor leukocyte injection but rather commencement of FK506 on day 1. Rejection was common during FK506 tapering in both groups. However group A showed a significantly later onset, a shorter period for reversal of the first rejection, and a significantly lower dosage of FK506 at the time of rejection. After the completion of immunosuppression, rejection occurred significantly later in group A than the control group with one animal surviving without immunosuppression on day 344. This is the first trial of a donor leukocyte injection combined with delayed FK506 administration in limb transplantation, which suggested that it could produce a modest but significant improvement in outcome.

Concerns on clinical application of composite tissue allotransplantation.

Composite tissue allograft has become a clinical reality: hands, vascularized femoral diaphyses, abdominal walls, a larynx have all been transplanted throughout the world. Conventional immunosuppressive protocol has shown to be sufficient and effective. Rejection has been prevented in most cases and when it did occur it was successfully reversed. Skin has been confirmed as the principal target of acute and chronic rejection. There has been no mortality or early graft losses and, particularly in hand transplantation, the survival graft rate is 91% with a follow-up period ranging from 6 months to 61 months. The side effects of immunosuppression are limited and include primarily transient hyperglycemia, an increase in creatinine values and some opportunistic infections (i.e. cytomegalovirus infection). Nerve regeneration and cortical reorganization have been demonstrated in hand transplantation. Functional results have been encouraging particularly for hand and larynx transplantation. Appropriate indications and patient selection, based particularly on patient motivation and compliance, are essential requirements for composite tissue allograft success.

Human hand transplantation: what have we learned?

Hand transplantation may become an important procedure for upper limb functional restoration. To date, 18 patients have been undergone 24 hand operations in the world. Initial results are extremely promising; the functional results are apparently superior to those obtained with prostheses. We report on the combined French and Italian experience of six patients (eight hands), which is based on a jointly devised protocol and represents the largest available clinical series. Six male patients aged 43, 33, 35, 32, 33, and 22 years received either a single right hand-dominant transplantation (four cases) or a simultaneous double hand transplantation (two cases). The time since the amputation ranged from 3 to 22 years. The level of transplantation was at the wrist in five cases (six hands) and at the distal forearm in two cases (two hands). Cold ischemia averaged 11.5 hours. Three patients simultaneously received additional full-thickness skin taken from the donor and transplanted onto their left hip area. This skin served as a source for biopsies and as an additional area to monitor rejection (distant sentinel skin graft). The immunosuppressive protocol included polyclonal antibodies (three patients) or monoclonal anti-CD 25 antibody (three patients), tacrolimus, mycophenolate mofetil, and prednisolone. No surgical complications occurred. Skin rejection occurred at least once in all patients at a mean of 40 days postoperatively. Three patients recovered protective and some discriminative sensation in their palm and fingers. Two patients are recovering sensation, but are still in the early phases of the regenerative process, due to the short time since the transplantation. One patient was not compliant with the immunosuppressive therapy, and underwent uncontrolled rejection and reamputation.

Experimental limb transplantation, part II: excellent return of function and indefinite survival after withdrawal of immunosuppression.

In this study the three components of an immunosuppressive combination therapy were gradually withdrawn in a rat limb transplantation model to evaluate the effects on long-term survival of the grafted limbs, rejection rate, and functional recovery. The procedure was performed in 16 rats across a strong Brown Norway to Fischer 344 histocompatibility barrier. Eight animals served as a control group that was not given any antirejection therapy and rejected their limb within a few days. The remaining eight animals were administered a 2-week course of immunosuppressive therapy including tacrolimus (TRL; 2 mg/kg/d), mycophenolate mofetil (MMF; 15 mg/kg/d), and prednisolone (Pred; 0.5 mg/kg/d). At 2 weeks, Pred and MMF were simultaneously tapered by 20% of the dosage every week; by week 7 the animals were on TRL only. TRL was then tapered at the same rate (20% every week) to a maintenance dose of 0.6 mg/kg/d at week 12. After 6 months the immunosuppression was stopped. Four of 8 animals did not reject throughout the study up, to the 1-year endpoint. At this stage they show excellent functional outcomes, evaluated by clinical tests and walking tract analysis. The remaining four rats developed a rejection at an average of 267 days postoperatively (range 224 to 302 days), corresponding to an average of 87 days (range 44 to 122 days) without any immunosuppression. They were sacrificed as soon as rejection was confirmed for histological examination of the various tissues. This study showed that a triple combination therapy provides excellent long-term functional outcomes of the transplanted limbs, with no rejection episodes, no side effects, or complications, even 6 months after withdrawal of all immunosuppressive components, suggesting the possible emergence of tolerance.

Experimental limb transplantation, part I: identification of an effective tapered triple combination immunosuppressive regime.

Limb transplantation was performed across the Brown Norway to Fischer 344 histocompatibility barrier in rats to evaluate the effects of triple combination immunosuppressive therapeutic regimens. Sixty rats were divided into five groups: group I (F344 to F344) isograft controls group II (BN to F344) allograft controls received no immunosuppressive treatment. Groups III and V (BN to F344) received various exposures to tacrolimus (TRL), mycophenolate mofetil (MMF) and prednisolone (Pred) for two weeks: namely, group III: TRL 0.5 mg/kg/d; MMF 10 mg/kg/d; Pred 0.5 mg/kg/d; group IV: TRL 2 mg/kg/d, MMF 15 mg/kg/d, Pred 0.5 mg/kg/d; and group V: TRL 3 mg/kg/d; MMF 20 mg/kg/d; Pred 0.5 mg/kg/d. After 2 weeks, group III and V animals underwent a simultaneous 20% taper of Pred and MMF each further week such that by week 7 the animals were only on TRL. At this time TRL was tapered at the same rate (20% every week) to a maintenance dose of 0.6 mg/kg/d. Evidence of rejection was sought by daily visual observation for swelling, redness, erythema, edema, or skin necrosis. Salvage treatment was used only if rejection occurred after the first 7 weeks, namely, reversing to 100% of the initial TRL dose in that group for 2 weeks with a subsequent taper. Skin and muscle biopsies were obtained from grafted limbs on day 3, 13, 24, 35, and at the endpoint (9 months or uncontrollable rejection). There was no rejection in group I, while all animals showed acute rejection as expected in group II. All group III rats displayed a similar though delayed acute rejection, showing that the regimen was not therapeutic. Rats in group IV displayed the best results, namely, 10 of 12 (83%) with no rejection or side effects at 9 months. Rats in group V displayed numerous, unacceptable side effects due to overtreatment with a 1-month mortality rate of 50%. This study shows that low-dose TRL in combination with MMF and Pred may achieve excellent long-term results of composite tissue transplants. TRL can be used alone as maintenance therapy following an initial loading dose and a tapering period. Rejection is easily reversed by only temporarily increasing the TRL dose.

Experimental limb transplantation, part III: induction of tolerance in the rigorous strain combination of Brown Norway donor to Lewis recipient.

The complete withdrawal of immunosuppressive therapy after hind-limb transplantation across a strong histocompatibility barrier (Brown-Norway to Lewis) included a low-dose combination of FK506, mycophenolate mofetil (MMF), and prednisone. MMF and prednisone were tapered and withdrawn between weeks 2 and 7. From weeks 8 to 24, Group 1 animals (n=23) had FK506 tapered; for those in Group 2 (n=11) the dose of FK506 was not changed. At week 24, FK506 was stopped. The six limb grafts in Group 1 (26%) that achieved the 1-year end-point uneventfully showed chimerism by bone marrow and skin grafting supporting the presence of donor-specific tolerance. Rejection, which was common during tapering of FK506, was reversed by salvage therapy. All limbs were rejected postwithdrawal in Group 2. This study showed that tapering of FK506 combined with salvage therapy may allow long-term survival of some transplanted limbs after complete withdrawal of immunosuppressive therapy despite a complete MHC barrier.

[First transplantation of two hands: results after 18 months]. / Première transplantation des deux mains: résultats à 18 mois.

AIM OF THE STUDY: The previous results achieved in single hand transplantations confirmed the feasibility of this procedure and encouraged us to perform the first human double hand transplantation, which was performed in January 2000. In the present study we reported the results obtained eighteen months after transplantation. PATIENT AND METHODS: The recipient was a 33-year old man suffering from a traumatic amputation of both hands in 1996. Surgery included procurement of the upper extremities from a 18-year old multiorgan cadaveric donor, preparation of the graft and recipient's stumps, transplantation of the hands, which included bone fixation, arterial and venous anastomoses, nerve suture, joining of tendons and muscles, and skin closure. Immunosuppressive protocol included tacrolimus, prednisone and mycophenolate mofetil. An intensive rehabilitation program was performed. Follow-up included immunological tests, skin biopsies, arteriography, bone scintigraphy, electromyography and brain functional magnetic resonance imaging. RESULTS: No surgical complications, infectious complications and graft-versus-host-disease occurred. Two episodes of acute skin rejection were demonstrated and they were completely reversed increasing steroid dose. Nerve regeneration and cortical reorganization were shown. Sensorimotor recovery was encouraging and life quality improved. CONCLUSION: This double hand transplantation showed that conventional immunosuppressive protocol is effective and safe as well as that functional results are at least as good as those achieved in replanted upper extremities.