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PubMedDate not supplied

Is oxygen consumption of surviving tissues determined by the oxygen tension of the suspension medium?

Oxygen tension in the suspension medium and oxygen uptake of the isolated diaphragm of the mouse have been determined simultaneously with systematic variation of shaking frequency and oxygen concentration of the gas phase. Oxygen tension in the suspension medium reaches its final value during the usual equilibration period of 10 minutes and remains constant for the whole measuring period. Each combination of shaking frequency and oxygen concentration of the gas phase results in a reproducible value of oxygen tension in the medium. Equal oxygen tension in the fluid phase can be attained by different combinations of shaking frequency and oxygen concentration of the gas phase. Oxygen uptake at the same oxygen tension of the suspension medium can be very different; it is the higher the higher the shaking rate in the combination. On the other hand the same oxygen consumption of the tissue samples can be observed with highly different oxygen tensions in the medium. It must be concluded from the data in this paper, that the influence of shaking rate per se on the oxygen uptake of isolated tissue can be of the same order as the influence of oxygen tension.

Animals↗
PubMed1979

Factors from fibroblasts promote pancreatic islet B cell survival in tissue culture.

A possible role for fibroblasts in promoting the survival and function of islet B cells in tissue culture was examined by the addition of fibroblasts from a mouse embryo cell line (3T3-L2) to islet cell monolayer cultures prepared from newborn rat pancreases. Co-culture of islet cells with fibroblasts significantly increased the recovery of insulin in medium and cells after 7 days of culture in medium supplemented with 10% serum, and prevented the deterioration of islet cells cultured in serum-free medium. Similarly- serum-free medium, conditioned by cultures of either 3T3-L2 fibroblasts or fibroblasts freshly isolated from newborn rat pancreases, maintained the release and content of insulin in islet cell monolayer cultures at levels four- to eightfold higher than in control serum-free medium. Serum-free, fibroblast-conditioned medium also enhanced the survival of intact islets maintained in free-floating culture for 28 days. The active factor(s) in fibroblast-conditioned medium has a high molecular weight and is heat-stable. We conclude that fibroblastic cells produce a macromolecular factor(s) capable of enhancing the survival of functional islet B cells in tissue culture.

Animals↗
PubMed1978

[Comparative investigations concerning the influence of pilocarpine and aceclidine on the glucose consumption of surviving ocular tissues (author's transl)].

Conservative glaucoma therapy repeated during a whole lifetime raises the question of medicamentuous tolerance. Recently, cultivation of normal lens epithelia and of iris tissue has made possible determination of metabolic functions with and without application of different medicaments. Preceding experiments revealed a diminution in glucose consumption by these tissues after addition of pilocarpine. Comparative studies show 0.25 g/100 ml medium to be maximum concentration of aceclidine allowing cellular survival. With this dilution, the glucose metabolism of lens epithelia was much more sensitive to aceclidine than to pilocarpine. This was less true for iris tissue. Accordingly, the lens of an aceclidine-treated patient requires careful observation.

Animals↗
PubMed1977

Correlation between local oxygen tension in muscle tissue and survival time in tourniquet shock.

Tourniquet shock was induced in rabbits by constricting one hind leg for 4 hr. Local pO2 on muscle surface was measured by a multiwire platinum electrode according to the method of Kessler. Untreated animals showed anoxic tissue areas after a period of 30 min of reperfusion. All these animals died in shock within 3-4 hr. The glucocorticoid, prednisolone (20 mg/kg), and the proteinase inhibitor, Trasylol (20,000 KIU/kg), were administered 5 min bfore release of the tourniquet. These animals showed normal pO2 values during the 2-3 hr observation period. Tourniquet shock was prevented and survival time prolonged by these agents. This protective effect could be correlated to the oxygen tension in the ischemic region.

Animals↗
PubMed2026

Beyond survival: Testicular tissue cryopreservation for fertility preservation during childhood cancer, experiences from a single center.

INTRODUCTION: Approximately 30% of all male childhood cancer survivors receive gonadotoxic therapy increasing their risk for infertility. The only current option for potential fertility preservation in prepubertal males is through testicular tissue cryopreservation (TTC), available through clinical trials. Our aim was to evaluate our experience and identify barriers to enrollment in the TTC study. METHODS: A retrospective review was conducted to describe a single center experience with TTC, including an assessment of factors impacting the decision to enroll or not enroll in the TTC trial. RESULTS: A total of 61 patients were found to be eligible for enrollment in the TTC trial, with 23 patients (34%) choosing to enroll and undergo testicular tissue cryopreservation including 19 (83%) oncology patients. In patients who underwent TTC there were no unexpected delays in starting disease directed therapy. For families that declined enrollment, many did not see fertility preservation as a priority at the time of counseling. (n = 17, 44%). Other barriers included concerns about post-operative complications and a feeling of being overwhelmed at the time of counseling. DISCUSSION: Despite being the only preservation option for pre-pubertal boys facing risk of infertility, TTC enrollment was not pursued by a majority of eligible patients and families. Identifying potential barriers or misconceptions, particularly in regard to post operative complication risks, offer opportunities for improved counseling and education. Early introduction of the Fertility Navigation team allows for procedural coordination success and access for patients that are interested. Success is not measured in how many patients proceed with TTC, rather that all patients have the opportunity for counseling and discussion. CONCLUSION: TTC can be offered and completed safely without delays in disease-directed treatment timelines. A Fertility Navigation Program allows for equal opportunity for education and enrollment on TTC protocol which should be the goal for pediatric institutions, though is not pursued by many patients. A majority of those who declined the study did not see fertility as a priority at the time of treatment while others were concerned regarding peri-operative risks.

Humans↗
PubMed1977

Effect of a new antithrombotic agent at microvenous anastomotic sites.

In the search for a suitable agent to prevent thrombosis at microvenous anastomotic sites, a double-blind sequential trial was performed to evaluate the effect of a new potent antithrombotic agent, 6-methyl-1,2,3,5-tetrahydroimidazo [2, 1-b] quinazolin-2-one hydrochloride monohydrate (BL3459). Rabbit neck veins 1.5 mm in diameter, were chosen for study and were anastomosed with Nakayama ring pins. In a comparison with heparin, the results show a highly statistical diminution in thrombosis rates when using BL3459. It would appear that this new compound would substantially improve tissue survival if it were adopted for use clinically for grafting autologous tissue that is based on an anastomosed microvascular pedicle. It could also prove to be clinically useful to treat a variety of problems requiring an antithrombotic agent.

Animals↗
PubMed1992

Attenuation of reperfusion-induced lipoperoxidation by systemic use of oxygen radical scavengers after pedicle occlusion.

Oxygen free radicals are implicated to cause tissue injury during ischemia and reperfusion and may play a central role in the no-reflow phenomena. Modulation of these substances has been suggested as a means of decreasing the amount of tissue loss due to ischemia and subsequent reperfusion. Pretreatment of tissues with a variety of agents has been reported to minimize the production of oxygen radicals and augment tissue survival after an ischemic insult. Ischemic clinical situations, however, usually present unexpectedly and thus pretreatment is not feasible. Our study evaluated the activity and effect of free radical scavengers delivered systemically during the ischemic interval to an ischemia/reperfusion rat intestinal model. Superoxide dismutase and dimethylthiourea were given systemically after occlusion and reperfusion to simulate a clinical sequence of a failing flap, that is, the vascular compromise, the diagnosis, and the successful resolution of the vascular embarrassment. Measurements of malonyldialdehyde (MDA), the end product of lipoperoxidation of cell walls, were compared with controls. Tissue histology was assessed and correlated with the use of these agents. A third group of rats was systemically alkalinized to attempt to shift the Bohr curve and decrease free oxygen substrate in the ischemic tissues on reperfusion. Rats treated with superoxide dismutase and dimethylthiourea showed significant reductions of MDA compared with nontreated rats (p less than 0.05), indicating attenuation of reperfusion lipoperoxidation. Systemic alkalinization of the rats did not significantly change the levels of MDA. Tissue histology showed severe injury in all ischemic groups regardless of the level of MDA.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Human cortical neuronal cell line (HCN-1): further in vitro characterization and suitability for brain transplantation.

The human neuronal cell-1 (HCN-1) line has recently been established. Under favorable conditions, these cells differentiate into mature neuronal phenotypes. Here we report on further characterization of these cells. Cultured HCN-1 cells express fibronectin immunoreactivity and grow well on fibronectin substrate but do not respond to human bFGF. In the undifferentiated state, some HCN-1 cells show MHC class I antigen expression. After differentiation, HCN-1 cells and their processes are MHC class I negative. On the other hand, interferon-gamma stimulation enhances MHC class I expression but does not induce MHC class II immunoreactivity. Our in vitro data indicate that HCN-1 cells express mixed characteristics, including both neuronal and mesenchymal markers, and are consistent with the suggestion that the HCN-1 cell line resembles an immature neuroepithelial cell precursor with a complex origin. One possible application of the use of the HCN-1 cells includes intracerebral transplantation. We also examined the survival of dissociated HCN-1 cells implanted into rat brain parenchyma. The host animals were not immunosuppressed. Despite expression of MHC class I antigens, small clusters of HCN-1 cells survived in the rat brain. These xenografts did not induce distinct immunological responses within the host brain tissue. Surviving HCN-1 cells demonstrated similar features to those observed in culture. Our preliminary results suggest that the HCN-1 cell line would be suitable for intracerebral transplantation in primates or humans. However, it may be that short-term host immunosuppression or addition of HCN-1 cell differentiation factors would be beneficial for enhanced cell survival.

Animals↗
PubMed1975

Readjustment of retinotectal projection following reimplantation of a rotated or inverted tectal tissue in adult goldfish.

1. The pattern of visual projection from the retina on to the optic tectum following reimplantation of a piece of the tectal tissue was studied with neurophysiological mapping methods in adult goldfish. 2. When a rectangular piece of the tectum was dissected, lifted free, and then reimplanted to the same tectum after rotation by 180 degrees around the dorsoventral axis, the re-established visual projection later showed a complete reversal of retinotopic order within the reimplanted area with reference to the normal projection on to the intact surrounding area of the same tectum. The localized reversal was observed as early as 65 days, and also as late as 721 days after the 180 degree rotated reimplantation. 3. If a square piece of the tectal tissue was reimplanted after rotation by 90 degrees anticlockwise around the dorsoventral axis, the restored visual projection later showed a corresponding localized 90 degrees rotation within the reimplanted ares. 4. When the entire laminar structure of a dissected tectal tissue was inverted, and the reimplanted upside-down along the same rostrocaudal axis of the tectum, the restored visual projection on to the inverted tectal reimplant was found to be organized in a reverse retinotopic order along only the mediolateral axis within the reimplanted area. The restored visual projection retained a correct retinotopic order along the rostrocaudal axis. The same trends were also observed after regeneration of the optic fibres following section of the contralateral optic nerve. 5. If the inverted tectal tissue was reimplanted along the same mediolateral axis of the tectum, the re-established visual projection showed a localized reversal of retinotopic order along only the rostrocaudal axis within the reimplanted area. Sectioning the contralateral optic nerve made no difference to the result. 6. These results suggest that a piece of adult tectal tissue retains its original topographic polarity regardless of the orientation of reimplantation after either a rotation or an inversion. Furthermore the retention is not a short-lived transitory phenomenon. It persisted as long as the reimplanted tissue survived. 7. Histological examination of the operated tecta revealed that the reimplanted tectal tissues underwent a severe derangement in their laminar structures. It was impossible to identify the main target zone of retinotectal projection (the stratum fibrosum et griseum superficiale) or the central cellular layer (the stratum griseum centrale) in the reimplants. The prominent feature of the deranged tectal tissue was irregular vortices of tangled fibre bundles. Sparse tectal neurones of bipolar and granular types were irregularly scattered in the deranged structure of the reimplant. 8. Thus, the retention of original topographic polarity did not require an integrity of the cytoarchitectonic structure of the reimplanted tectal tissue.

Action Potentials↗
PubMed1979

Histometric analysis of human skin in organ culture.

A histometric method is used for the study of human skin kept in organ culture in a defined medium for up to 10 days. The method provides quantitative, reproducible data on tissue survival, cell migration, and cellular differentiation (keratinization). With this method, the behavior of epidermal skin tissue can be effectively monitored during organ culture. As quantitative data are obtained, even subtle changes can be accurately demonstrated, and accumulated data may be subjected to statistical analysis. The various applications of this method are pointed out.

Adult↗
PubMed1979

The anatomic rationale for abdominal lipectomy.

Changes occur in the vascular and lymphatic flow and in the sensory pattern of the superficial abdominal wall during abdominal lipectomy. The development of these systems, their anatomic descriptions in the abdominal wall, and the changes created by the surgery are documented to explain tissue survival following the procedure.

Abdominal Muscles↗
PubMed1978

External skeletal fixation in severe limb trauma.

Ten patients with 12 severe limb injuries managed by external skeletal fixation over 2 years are presented. Two major indications for external skeletal fixation divided the fractures into groups: A) extensively open fractures requiring wound care and closure by other than primary methods, and B) grossly unstable fractures requiring stabilization for soft-tissue support and fracture alignment. Group A was composed of five extremity fractures with skin and muscle loss and deep tissue contamination. Wound management was the primary problem. Wound closure, prevention of an infection, and limb salvage were the treatment goals in this group. Group B was seven severely comminuted extremity fractures with significant swelling and in some cases, questionable soft-tissue survival. Five were open, but not extensively. Instability was the primary problem. Fracture control, soft-tissue support, and limb salvage were the treatment goals in this group. Mean followup period for all fractures was 9.4 months. No amputations, deep infections, or deaths resulted. Wound care and closure were facilitated in all open fractures. Loss of contused tissues with marginal vascular supply was felt to be minimized. Delayed unions were common in both groups. Two malunions and one nonunion occurred. Treatment goals in both groups were accomplished.

Adolescent↗
PubMed1992

The evaluation of pharmacologic agents on composite graft survival.

This study assessed the efficacy of various pharmacologic agents in improving composite graft viability in 60 New Zealand white rabbits given bilateral auricular composite grafts. Treatments included methylprednisolone preoperatively and for 3 days postoperatively or for 7 days postoperatively only; chlorpromazine, dimethylsulfoxide, or superoxide dismutase preoperatively; or indomethacin preoperatively and for either 3 or 7 days postoperatively. Four treatment modalities yielded a statistically significant decrease in percentage of necrosis. Methylprednisolone, when given preoperatively and continued postoperatively, produced the greatest increase (77%) in composite graft tissue survival. Dimethylsulfoxide, chlorpromazine, and indomethacin for 3 days were also effective, but to a much lesser extent. It is speculated that these agents may help stabilize cell membranes during the anoxic phase of plasmic imbibition and minimize cellular edema until revascularization can occur.

Animals↗