Induced Regeneration of Hindlimbs in the Newborn Opossum

The North American marsupial, Didelphys virginiana, has provedto be uniquely suited for studies of replacement of mammalianlimb. The newborn opossum provides the rare opportunity to performchronic experiments on extremely young mammalian limbs. Sincethis marsupial is born without lymphocytes, xenoplastic as wellas homoplastic transplants are tolerated; supplementary nervetissue was transplanled to newborn hindlimbs and the limbs wereamputated immediately above the ankle. When the implant remainedin place, a regenerative response ensued. Results of controlexperiments indicate that neither the trauma of simple amputation,the trauma of implantation, nor the implantation of other tissuescan evoke the response which results after implanting nervetissue. These studies demonstrate that young opossum limbs arecapable of regenerating when additional nervous tissue is supplied.     

Molecular mechanisms underlying delayed apoptosis in neutrophils from multiple trauma patients with and without sepsis

Delayed neutrophil apoptosis and overshooting neutrophil activity contribute to organ dysfunction and subsequent organ failure in sepsis. Here, we investigated apoptotic signaling pathways that are involved in the inhibition of spontaneous apoptosis in neutrophils isolated from major trauma patients with uneventful outcome as well as in those with sepsis development. DNA fragmentation in peripheral blood neutrophils showed an inverse correlation with the organ dysfunction at d 10 after trauma in all patients, supporting the important role of neutrophil apoptosis regulation for patient's outcome. The expression of the antiapoptotic Bcl-2 protein members A1 and Mcl-1 were found to be diminished in the septic patients at d 5 and d 10 after trauma. This decrease was also linked to an impaired intrinsic apoptosis resistance, which has been previously shown to occur in neutrophils during systemic inflammation. In patients with sepsis development, delayed neutrophil apoptosis was found to be associated with a disturbed extrinsic pathway, as demonstrated by reduced caspase-8 activity and Bid truncation. Notably, the expression of Dad1 protein, which is involved in protein N-glycosylation, was significantly increased in septic patients at d 10 after trauma. Taken together, our data demonstrate that neutrophil apoptosis is regulated by both the intrinsic and extrinsic pathway, depending on patient's outcome. These findings might provide a molecular basis for new strategies targeting cell death pathways in apoptosis-resistant neutrophils during systemic inflammation.     

Risk of infection following penetrating abdominal trauma: a selective review

Post-operative infectious complications following penetrating abdominal trauma are a major cause of morbidity and contribute significantly to increased length of hospitalization and costs of patient care. Our recent study suggests the individual patient's probability of major infection following traumatic intestinal perforation is high and can be predicted from risk factors identified at the time of surgery. The determinant of primary importance for development of infection confirmed by this study is peritoneal contamination by intestinal contents. Other significant risk factors (p less than 0.05) were number of organs injured, number of units of blood administered, ostomy formation for left colon injury, and the patient's age. Risk of infection can be calculated from these data and could potentially be used to guide post-operative decisions. Areas of trauma care in which alteration of therapy might result in significant savings include choice of antibiotics, duration of antibiotic administration, and wound management. This study supports the use of standardized operative procedures and parenteral antibiotics effective against endogenous aerobic and anaerobic organisms. If such observations continue to be supported by further randomized prospective studies, there is tremendous potential to further tailor surgical management for the individual patient in a more cost-effective manner.     

Survival of both young and aged sympathetic neurons in the adrenal cortex after autotransplantation

Sympathetic ganglion tissue of 3-months- and 18-months-old Fischer-344 rats was autotransplanted into the adrenal gland in order to determine the effect of aging on the survival of grafted neurons. Adrenal cortex was chosen as the host tissue because it is well vascularized and has a high concentration of glucocorticoids, which stimulate the synthesis of catecholamines. At 4 weeks following the transplantation, the density of neurons was decreased in all transplants, but approximately the same proportion of remaining neurons showed tyrosine hydroxylase immunoreactivity as in intact ganglia. At 8 weeks, a subpopulation of large neurons showed an increased accumulation of age pigment. The heavily pigmented neurons were usually devoid of catecholamines, whereas small non-pigmented neurons frequently showed strong catecholamine histofluorescence and tyrosine hydroxylase immunoreactivity. There was no marked difference between old and young animals in the survival of transplanted neurons. The results show that the sympathetic neurons from both 3-months-and 18-months-old animals survived the autotransplantation procedure. The humoral environment of the adrenal cortex may be beneficial for the restoration of the integrity of sympathetic neurons.     

Survival of both young and aged sympathetic neurons in the adrenal cortex after autotransplantation

Summary Sympathetic ganglion tissue of 3-months- and 18-months-old Fischer-344 rats was autotransplanted into the adrenal gland in order to determine the effect of aging on the survival of grafted neurons. Adrenal cortex was chosen as the host tissue because it is well vascularized and has a high concentration of glucocorticoids, which stimulate the synthesis of catecholamines. At 4 weeks following the transplantation, the density of neurons was decreased in all transplants, but approximately the same proportion of remaining neurons showed tyrosine hydroxylase immunoreactivity as in intact ganglia. At 8 weeks, a subpopulation of large neurons showed an increased accumulation of age pigment. The heavily pigmented neurons were usually devoid of catecholamines, whereas small non-pigmented neurons frequently showed strong catecholamine histofluorescence and tyrosine hydroxylase immunoreactivity. There was no marked difference between old and young animals in the survival of transplanted neurons. The results show that the sympathetic neurons from both 3-months-and 18-months-old animals survived the autotransplantation procedure. The humoral environment of the adrenal cortex may be beneficial for the restoration of the integrity of sympathetic neurons.     

Difference in shape of bone formed by isolated calvarial and scapular osteoblasts transplanted under various conditions

To study the influence of transplantation conditions on early stages of osteogenesis, isolated calvarial or scapular osteoblasts were injected into the leg or dorsal muscles (free transplants) or implanted after seeding on fragments of devitalized parietal bones (supported transplants) into dorsal muscles. The cross-sections of bone islands formed by calvarial osteoblasts in the different types of transplants were then compared according to their maximal breadth and length. Moreover, the same dimensions of pieces of bone formed by scapular osteoblasts in supported transplants were compared with those of bones formed in free transplants into leg muscles. Finally, comparison of the dimensions of cross-sections of supported transplants of calvarial and scapular osteoblasts was done. Calvarial osteoblasts in dorsal muscles produced a slightly higher percentage of wider and longer islands than those in leg muscles. In supported transplants of calvarial osteoblasts the percentage of narrow bone islands (breadth less than 100 microns) was considerably higher than in free transplants. Similarly, the percentage of narrow cross-sections in bones formed by scapular osteoblasts was higher in supported than in free transplants. In supported transplants of calvarial osteoblasts the percentage of narrow islands was higher than in similar transplants of scapular bone cells. It is suggested that the differences in shape of pieces of bone formed in supported and free transplants reflect the difference in mechanical conditions to which the bone cells were subjected. Furthermore, in supported transplants devitalized parietal bones could form a barrier for diffusion of nutrients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Total ear reconstruction in the devascularized temporoparietal region: I. Use of the contralateral temporoparietal fascial free flap

Total ear reconstruction by the use of contralateral temporoparietal fascial free flap and autogenous costal cartilage was performed in 16 patients presenting with a devascularized temporoparietal region resulting from trauma or prior surgery. The microsurgical success rate was 87.5 percent (14 of 16 transplants). On evaluation of the final aesthetic result in 11 patients followed up for more than 3 years, nine patients were graded good-to-excellent and two patients exhibited fair-to-poor results. Despite the relatively long operating hours and the comparatively low microsurgical success rate, ear reconstruction by autogenous tissue transplantation has proved to be an encouraging and worthwhile experience. This article presents the clinical cases and discusses the technical details.     

Regenerative medicine in Parkinson's disease: generation of mesencephalic dopaminergic cells from embryonic stem cells

Cell replacement therapy has been proposed as a means of replacing specific populations of cells lost through trauma, disease or ageing. Parkinson's disease is a progressive neurodegenerative disorder caused by the loss of midbrain dopaminergic neurons. Intrastriatal transplants of human foetal mesencephalic tissue in Parkinson's patients have demonstrated clinical efficacy, but the limited availability of tissue precludes systematic use of this treatment. Human embryonic stem cells are capable of unlimited self-renewal and can differentiate into cells representative of all three germ layers, including cells of the central nervous system. These cells may thus provide a relatively unlimited source of cells for transplantation, if appropriate differentiation protocols to generate highly enriched and specific populations of neural cells can be developed.     

Results of unrelated umbilical cord blood hematopoietic stem cell transplantation

The number of umbilical cord blood transplants is increasing worldwide. The purpose of Eurocord is to evaluate the results and to compare the outcome of umbilical cord blood transplants with allogeneic bone marrow transplants. Data have been reported to Eurocord by multiple transplant centers. Close links have been established with the cord blood banks through Netcord. Bone marrow transplant data have been provided by transplant centers and also through the European Group for Blood and Marrow Transplantation (EBMT) and International Bone Marrow Transplant Registries (IBMTR). Eurocord has analyzed the outcome of unrelated umbilical cord blood transplants from 121 transplant centers and 29 countries. The results showed that survival with unrelated mismatched umbilical cord blood transplants was comparable to that with unrelated bone marrow transplants. Engraftment with cord blood was delayed, resulting in an increased incidence of early transplant complications. The incidence of acute and chronic graft-vs.-host disease was reduced with cord blood grafts even in human leukocyte antigen (HLA)-mismatched transplants and in adults. In patients with leukemia, the rate of relapse was similar to the rate of relapse after bone marrow transplant. The overall event-free survival with umbilical cord blood transplantation was not statistically different when compared to bone marrow transplants. This large registry study confirms the potential benefit of using umbilical cord blood hematopoietic stem cells for allogeneic transplants.     

Effects of different numbers of ectopic pituitary transplants on regulation of testicular LH/hCG and prolactin receptors in the hamster (Mesocricetus auratus)

Adult male hamsters were given transplants of 1/2, 1, 2, 3 or 4 pituitaries under the kidney capsule and were killed 4 weeks later. Pituitary transplants produced a significant, dose-related increase in plasma prolactin levels, no changes in plasma LH and an increase in plasma FSH. Concentration of LH/hCG receptors in the testes was significantly increased in animals with 2 or 3 transplants and concentration of testicular prolactin receptors was significantly increased in those given 2 transplants. The apparent stimulatory effects of 1/2, 1 or 4 transplants on testicular LH/hCG and prolactin binding were not statistically significant. Some of the animals were injected with 0.3 i.u. hCG/g body weight 24 h before being killed. This produced a significant reduction in the levels of prolactin receptors and an apparent reduction in the levels of LH/hCG receptors in the testes. Elevation of plasma testosterone concentrations in response to hCG was significantly greater in animals given 3 or 4 pituitary transplants than in the remaining groups. These results provide further evidence that prolactin increases the number of LH/hCG and prolactin receptors in the hamster testis and suggest that changing the number of ectopic pituitary transplants may result in biphasic effects on the testis, with 2 or 3 transplants being maximally stimulatory.     

Morphological aspects of muscle fiber regeneration

Although striated muscle displays remarkable regenerative potential, the three-dimensional cytoarchitecture of the regenerated myofibers is different from that of myofibers formed during fetal development. It has been demonstrated with spaced, serial ultrathin sections that the regenerating myotubes that occur spontaneously (i.e., without secondary trauma) in dystrophic (dy2J) murine muscle and the regenerating fibers found in free whole-muscle transplants of normal, murine extensor digitorum longus muscles branch and recombine, forming a complex syncytium. Multiple motor end-plate regions are observed on the branched syncytia found in dystrophic muscle. Branched fibers persist in long-term grafts and are found with a frequency that indicates that they should be of physiological significance. Although the number of myofibers found in long-term grafts is approximately 68% of that found in control muscle, comparison of the diameter distributions of the regenerated muscle fibers with age-matched control fibers indicates that many of the regenerating fibers fail to achieve normal size. Type IIb fibers appear to be more growth inhibited than type IIa fibers. The size of the motoneuron pool to grafted muscles is smaller than that to control muscles.     

Human lymphomas transplanted in nude mice

This study was carried out to determine the take rate of malignant lymphomas transplanted subcutaneously in nude mice. Lymphoid tissue from patients with a variety of lymphoproliferative and lymphomatous disorders was employed, but only four (8.3% of total) non-Hodgkin's lymphomas of various types grew in the nude mice. These transplants were from patients with lymphoplasmacytic, lymphoblastic, immunoblastic and centroblastic lymphomas; two of them were serially transferred. High grade malignant lymphomas seem easier to transplant than low grade ones. In each case, the tumor growing in nude mice was similar to the patient's tumor. In one case, metastases were found in mesenteric lymph nodes and lung. Electron microscopic study showed that neoplastic cells were associated with peculiar dark cells the nature of which is discussed. Furthermore, in two transplanted lymphomas, neoplastic cells contained C type virus particles, indicating contamination by the murine xenotropic type C virus.     

The effect of hypertransfusion on the growth of mouse foetal liver cells transplanted into irradiated, adult recipients: failure to detect a differential effect between cells from early and late foetuses

Erythropoiesis can be reinstated in lethally irradiated mice by transplantation of adult bone marrow or liver cells from foetuses at any stage of gestation beyond the eleventh day. Hypertransfusion of the recipients abolishes erythropoiesis resulting from the transplants, even when the transplants are derived from foetuses at a very early stage of development. This suggests that erythropoietin is necessary for the successful growth of these early foetal transplants, at least in the environment of the irradiated recipient. These results are at variance with an earlier report on the susceptibility of early foetal liver transplants to suppression by hypertransfusion.     

Formation of a functional adrenergic input to intraocular cerebellar grafts: ingrowth of inhibitory sympathetic fibers.

The intraocular transplantation technique was used to study the ingrowth of peripheral sympathetic adrenergic nerves from the iris into transplants of fetal rat cerebellum, and the possible function of these nerves. The transplants, grown in oculo for one-half to eight months, were analyzed by fluorescence histochemistry and electrophysiological techniques. Peripheral sympathetic adrenergic fibers from the iris were able to grow into the cerebellar transplants and arborize in a pattern similar to that in situ, appearing in all three cortical layers and the noncortical areas of the transplants. The density of visible nerves without pretreatment and after preincubation in 10(-6) or 10(-5) M alpha-methylnorepinephrine was comparable to mature rat cerebellum. The spontaneous discharge of the Purkinje cells in oculo was inhibited by microiontophoresis of norepinephrine (NE) and amphetamine in sympathetically innervated, as well as sympathectomized transplants denervated by ganglionectomy. The NE response was blocked by the adrenergic beta-receptor blocker MJ-1999. GABA also inhibited the Purkinje cell activity while glutamate accelerated the discharge. Parenteral amphetamine inhibited Purkinje cell activity in sympathetically innervated transplants, but was ineffective in denervated transplants. The Purkinje cell spontaneous activity was inhibited by electrical stimulation of the NE fiber input through the cervical sympathetic trunk. This inhibition could be antagonized by parenteral reserpine or the beta-adrenergic antagonist propranolol. The responses of the Purkinje cells within the transplants to drugs and transmitters mimic those of the adult rat in situ. In view of the fluorescence histochemical evidence for an ingrowth of peripheral sympathetic adrenergic fibers into the cerebellar transplants, and the results of stimulating the sympathetic trunk, it is suggested that peripheral adrenergic fibers may be able to establish functional connections with the Purkinje cells similar to the cerebellar adrenergic synapses normally formed in situ by fibers from the locus coeruleus.     

Polyploidization of transplanted cardiac myocytes

Pieces of cardiac ventricular tissue of late embryonic or 1-day postnatal rats, implanted beneath the kidney capsule of adult syngeneic hosts, formed viable, beating transplants. these transplants were investigated over a 40-day postoperative course. In the transplants, cellular binucleation and nuclear polyploidization occurred according to the same schedule as in the heart in situ. The composition of the classes of myocytes was identical both in the hearts in situ and in transplants, but the number of non-diploid myocytes in the intact heart reached 90%, whereas in transplants it varied from 30 to 60%. In contrast to the heart in situ, myocytes in transplants grew feebly after the phase of polyploidization. From these data one can conclude that under conditions of transplantation the temporal sequence of cellular binucleation and nuclear polyploidization follows the normal course, but that a greater number of myocytes remain in a diploid state than is the case in the normal heart. The growth of cardiac myocytes seems to be related to their level of function.     

Effect of donor cell cycle stage on chromatin and spindle morphology in nuclear transplant rabbit embryos.

We investigated the influence of the cell cycle stage of the nuclear donor on prematurely condensed chromatin (PCC) and spindle morphology and on chromosome constitution in rabbit nuclear transplant embryos. The configuration of PCC following nuclear transplantation with G1, early S, and late S phase donor nuclei (G1, early S, and late S transplants, respectively) was characterized in whole mounts and chromosome spreads. In addition, the influence of the donor cell cycle stage on chromosome constitution in cleavage stage-manipulated embryos was determined. Within 2 h after fusion of the donor blastomere, the recipient oocyte cytoplasm was able to induce formation de novo of a metaphase plate associated with a spindle in G1, early S, and late S transplants. Metaphase chromosomes and spindle were intact in most cases of PCC in G1 transplants. However, these structures displayed minor abnormalities in early S transplants and gross abnormalities in late S transplants, such as incomplete or absent spindle formation and incomplete chromatin condensation. Normal chromosomes were present in G1 and early S transplants, whereas chromosome abnormalities were detected in late S transplants. The results indicate that morphology of prematurely condensed G1 and early S chromatin has a minor influence on chromosome constitution of manipulated embryos. That of late S chromatin, however, affects chromosome constitution in embryos and may account for reduced development of nuclear transplant embryos when late S phase donor nuclei are used.     

Permanent lip augmentation employing polytetrafluoroethylene grafts.

There is a paucity of literature regarding aesthetic enhancement of the lips. This is due to the lack of reliable techniques employing autogenous tissue and the reluctance on the part of surgeons to use an alloplastic implant in this anatomic region, which is superficial, subject to trauma, and must conform to innumerable geometric shapes. The ideal lip augmentation procedure should provide for a predictable, permanent enlargement without visible scars or donor-site deformity, can be customized to the particular patient's anatomy, and can be reversed if so desired. A series of 21 alloplastic lip implants employing polytetrafluoroethylene with a mean follow-up of 14.33 months is presented. The overall complication rate was 9.52 percent. Permanent lip augmentation can be achieved with alloplastic sheet grafts of polytetrafluoroethylene in a safe and predictable fashion. Stiffness of the lips develops with progressive thickness of the grafts. Grafts exceeding 3 mm in thickness should be avoided.     

The Importance of Transplant Size and Gap Width in the Botanical Enrichment of Species-Poor Grasslands in Britain

A series of five grasslands of differing agricultural productivity and species diversity was chosen for this study. Four of these areas were divided into three sub-plots, each under a different management regime (either mown, sheep, or cattle grazed). Each sub-plot was inoculated with 180 transplants comprised of 12 individuals of 15 perennial species. These species were chosen to provide a spectrum of ‘phytometers’ to evaluate the receptivity of the grasslands to species introduction. Half of the plants were 9-cm pot-grown transplants, the other half, 2-cm plug plants. One-third of each of the transplant sizes was inserted into either 0-cm, 15-cm, or 30-cm-diameter gaps. Evaluation of species enrichment success was made by monitoring the survivorship of the transplants over a three-year study period. The fifth grassland was already species-rich and, therefore, left untreated and used as a reference community. The species could be classified into three main groups on the basis of their survivorship: (a) species with higher survivorship for pot than plug transplants; (b) species that established significantly better as plug than as pot transplants; and (c) species that suffered equally high mortalities as either pot or plug transplants. For three out of the four grasslands, the size of competition-free gaps was not significant in enhancing survivorship for either pot or plug transplants. Gap creation only aided survivorship for the set of plug plants inserted into the most productive grassland. Transplant survival was strongly negatively correlated with soil P and K concentrations, and peak biomass. In this, the establishment phase, the three management treatment regimes did not have a significant differential effect on transplant survival. The results are discussed in relation to practical techniques for restoring species-poor grasslands using transplants.     

Craniocerebral injuries

The postconcussion syndrome is a definite entity, and the patient's complaints are due to legitimate injury. The following three factors contribute to the symptomatology:1. Headaches, caused by the associated sprain of the cervical spine with resultant radiculitis-giving rise to muscle spasm and suboccipital headaches.2. Vertigo, due to trauma of the vestibular and labyrinthine apparatus.3. A vasomotor imbalance and instability resulting from the reaction to "stress."In treatment of an unconscious patient great care must be taken to prevent anoxia and to balance the fluids and electrolytes. If coma develops following brain injury, hemorrhage into the cerebellar fossa as well as above the tentorium must be considered.