RESUMO
Aquaponics is an agricultural practice incorporating aquaculture and hydroponic principles. This study assesses the current system design and production practices of the aquaponic industry, compares these metrics by stakeholder group, identifies trends, and provides recommendations for future development. An electronic survey of aquaponic stakeholders was conducted from December 2019 to June 2020 targeting hobbyists, producers, and educators from various aquaponic-focused professional associations, email and social media groups. Of 378 total responses, 84% came from the United States and were clustered in plant hardiness zones five to nine. Aquaponic systems were commonly homemade/do-it-yourself (DIY), many of which incorporated commercially available (turn-key) technology. Most growers used coupled systems that integrated recirculating aquaculture systems and either deep-water culture (DWC) or media bed hydroponic units. Common plant lighting sources were sunlight and light emitting diode (LED). Water sources were typically municipal or wells. Personal labor input was typically less than 20 hrs/wk. Funding sources were primarily personal funds, followed by government grants, and private investor funds. System sizes varied greatly, but the median area was 50 to 500 ft2 for hobbyists and educators and 500 to 3,000 ft2 for producers. Respondents commonly sold vegetable produce, training and education, food fish, and microgreens. Tilapia and ornamental fish were commonly grown, with 16 other species reported. Common crops were lettuce, leafy greens, basil, tomatoes, peppers, and herbs with many additional lesser-grown crops reported, including cannabis. Overall, the industry still growing, with a large portion of stakeholders having less than two years of experience. However, veteran growers have remained in operation, particularly in the producer and educator groups. The survey results suggest a shift away from outdoor systems, media beds, tomatoes, ornamental fish, and perch production, and a shift toward decoupled systems, DWC, drip irrigation, and wicking beds, larger system area, leafy greens, and trout/salmon production compared to previous industry surveys. The reduced diversity of plant species grown suggest some level of crop standardization. Commercial producers tended to sell more types of products than other stakeholders, suggesting that diversification of offerings may be key to profitability. The combined production area specified by respondents indicates the industry has grown substantially in recent years. Finally, the presence of bank loan-funded operations suggests increased knowledge and comfort with aquaponics among lenders.
Assuntos
Aquicultura , Solanum lycopersicum , Agricultura , Animais , Aquicultura/métodos , Peixes , Humanos , Hidroponia/métodos , Lactuca , ÁguaRESUMO
The benefit of class II major histocompatibility complex (MHC) antigen matching to renal allograft survival, in the absence of immunosuppression, has been studied in partially inbred miniature swine. Permanent (greater than 6 mo) renal allograft survival was found in 30% of recipients of either class II only or fully matched grafts. Analysis of the survival of the class II-only matched grafts by specific recipient/donor haplotype combinations indicated that survival was regulated by at least three genetic factors, including antigen gene dose, a class I MHC allele-dependent effect, and non-MHC-linked immune response phenomenon. Animals accepting class II-matched kidneys developed spontaneous tolerance to the graft, despite mounting an initial immune response marked by renal damage and the development of serum cytotoxic antibodies directed at the donor MHC antigens. The antibodies were only of the IgM class, suggesting that conversion of the humoral response to IgG was blocked. After acceptance of the kidney, three out of five animals showed specific prolongation of donor skin grafts. At the time of rejection of these skin grafts, no decrease in renal function nor reappearance of anti-donor antibodies was observed.
Assuntos
Sobrevivência de Enxerto , Antígenos de Histocompatibilidade/imunologia , Teste de Histocompatibilidade , Transplante de Rim , Porco Miniatura/imunologia , Animais , Soro Antilinfocitário/biossíntese , Rejeição de Enxerto , Antígenos de Histocompatibilidade/análise , Antígenos de Histocompatibilidade/genética , Humanos , Tolerância Imunológica , Imunoglobulina G/biossíntese , Imunoglobulina M/biossíntese , Longevidade , Suínos , Doadores de TecidosRESUMO
BACKGROUND: Several approaches to gene therapy for cancer have yielded promising results in rodent models. The translation of these results to the clinical realm has been delayed by the lack of tumor models in large animals. We investigated the pattern of transgene (i. e., foreign or introduced gene) expression and virus vector elimination after systemic gene delivery using a thymidine kinase-negative vaccinia virus in a rabbit model of disseminated liver metastases. METHODS: VX-2 rabbit carcinoma cells were maintained by serial transplantation in the thigh muscles of New Zealand White rabbits, and disseminated liver metastases were established by direct injection of tumor cells into the portal vein of the animals. Different doses of a recombinant thymidine kinase-negative vaccinia virus vector encoding the firefly luciferase reporter gene (i.e., transgene) were injected into tumor-bearing rabbits. Transgene activity in tumors and other organs was measured at multiple time points thereafter. The pattern of development of antibodies against the vaccinia virus vector was also examined. Two-tailed Student's paired t test was used for comparisons of transgene activity. RESULTS: Transgene expression was increased in tumors by at least 16-fold in comparison with expression in other tissues by day 4 after vector injection (all P<. 001) and was maintained for approximately 1 week, providing evidence of tumor-specific gene delivery in this model. Rapid elimination of the circulating vector by the host immune system was observed. Anti-vector antibodies were detectable in serum as early as day 6 and were maintained for more than 3 months. CONCLUSIONS: Tumor-specific gene delivery is possible after systemic injection of a thymidine kinase-negative vaccinia virus vector in a model of rabbit liver metastases. Although the period of transgene expression appears limited because of a rapid immune response, the therapeutic window might be sufficient for an enzyme/prodrug gene therapy approach in clinical application.
Assuntos
Expressão Gênica , Terapia Genética/métodos , Vetores Genéticos , Neoplasias Hepáticas Experimentais/genética , Neoplasias Hepáticas Experimentais/terapia , Transgenes/genética , Vaccinia virus/genética , Animais , Anticorpos Antivirais/sangue , Linhagem Celular , Modelos Animais de Doenças , Ensaio de Imunoadsorção Enzimática , Feminino , Genes de Insetos/genética , Genes Reporter/genética , Genes Virais/genética , Vetores Genéticos/uso terapêutico , Haplorrinos , Células HeLa , Humanos , Neoplasias Hepáticas Experimentais/secundário , Luciferases/genética , Plasmídeos , Coelhos , Proteínas Recombinantes/genética , Timidina Quinase/deficiência , Timidina Quinase/genética , Fatores de Tempo , Vaccinia virus/enzimologia , Vaccinia virus/imunologiaRESUMO
Radiation injury to peripheral nerve is a dose-limiting toxicity in the clinical application of intraoperative radiotherapy, particularly for pelvic and retroperitoneal tumors. Intraoperative radiotherapy-related peripheral neuropathy in humans receiving doses of 20-25 Gy is manifested as a mixed motor-sensory deficit beginning 6-9 months following treatment. In a previous experimental study of intraoperative radiotherapy-related neuropathy of the lumbro-sacral plexus, an approximate inverse linear relationship was reported between the intraoperative dose (20-75 Gy range) and the time to onset of hind limb paresis (1-12 mos following intraoperative radiotherapy). The principal histological lesion in irradiated nerve was loss of large nerve fibers and perineural fibrosis without significant vascular injury. Similar histological changes in irradiated nerves were found in humans. To assess peripheral nerve injury to lower doses of intraoperative radiotherapy in this same large animal model, groups of four adult American Foxhounds (wt 20-25 kg) received doses of 10, 15, or 20 Gy to the right lumbro-sacral plexus and sciatic nerve using 9 MeV electrons. The left lumbro-sacral plexus and sciatic nerve were excluded from the intraoperative field to allow each animal to serve as its own control. Following treatment, a complete neurological exam, electromyogram, and nerve conduction studies were performed monthly for 1 year. Monthly neurological exams were performed in years 2 and 3 whereas electromyogram and nerve conduction studies were performed every 3 months during this follow-up period. With follow-up of greater than or equal to 42 months, no dog receiving 10 or 15 Gy IORT shows any clinical or laboratory evidence of peripheral nerve injury. However, all four dogs receiving 20 Gy developed right hind limb paresis at 8, 9, 9, and 12 mos following intraoperative radiotherapy. These experimental data suggest that intraoperative doses of less than 20 Gy may not result in clinically significant peripheral nerve injury with follow-up of 3.5 years. Longer (5 yrs) follow-up with planned sacrifice of the remaining dogs is scheduled to assess any late peripheral nerve damage.
Assuntos
Nervos Periféricos/efeitos da radiação , Lesões Experimentais por Radiação/fisiopatologia , Radioterapia/efeitos adversos , Animais , Cães , Eletromiografia , Período Intraoperatório , Músculos/inervação , Condução Nervosa/efeitos da radiação , Dosagem Radioterapêutica , Nervo Isquiático/efeitos da radiaçãoRESUMO
Radiation has been given intraoperatively to various abdominal structures in dogs, using a fixed horizontal 11 MeV electron beam at the Armed Forces Radiobiologic Research Institute. Animals were irradiated with single doses of 2000, 3000 and 4500 rad to a field which extended from the bifurcation of the aorta to the rib cage. All animals were irradiated during laparotomy under general anesthesia. Because the clinical use of intraoperative radiotherapy in cancer treatment will occasionally require irradiation of anastomosed large vessels and blind loops of bowel, the tolerance of aortic anastomoses and the suture lines of blind loops of jejunum to irradiation were studied. Responses in these experiments were scored at times up to one year after irradiation. In separate experiments both aortic and intestinal anastomoses were performed on each animal for evaluation of short term response. Response was graded by arteriography, gastrointestinal roentgenography, blind loop bursting pressure, and pathologic findings at autopsy and microscopic evaluation. The dogs with aortic anastomoses showed adequate healing at all doses with no evidence of suture line weakening. On long-term follow-up one animal (2000 rad) had stenosis at the anastomosis and one animal (4500 rad) developed an arteriovenous fistula. Three of the animals that had an intestinal blind loop irradiated subsequently developed intussusception, with the irradiated loop acting as the lead point. One week after irradiation, bursting pressure of an intestinal blind loop was normal at 3000 rad, but markedly decreased at 4500 rad. No late complications were noted after the irradiation of the intestinal anastomosis. Thus, it appears that adequate healing can take place with minimal risk of suture line breakdown even after a high single dose of irradiation (up to 3000 rad) to an anastomotic site. No late complications were observed after irradiation of intestinal anastomoses, but one needs to be cautious with regards to possible late stenosis at the site of an irradiated vascular anastomosis.
Assuntos
Aorta/cirurgia , Jejuno/cirurgia , Radioterapia/efeitos adversos , Animais , Aorta/efeitos da radiação , Cães , Feminino , Período Intraoperatório , Jejuno/efeitos da radiação , Masculino , Aceleradores de Partículas , Radioterapia de Alta Energia , Cicatrização/efeitos da radiaçãoRESUMO
Adult dogs were subjected to laparotomy and intraoperative electron irradiation after division and reanastomosis of aorta or after construction of a blind loop of small intestine having a transverse suture line and an end-to-side anastomosis. Dogs received intraoperative irradiation of both intact and anastomosed aorta or intestine in doses of 0, 2000, 3000, or 4500 rad. Animals were sacrificed at seven days or three months following treatment. At 24 hours prior to sacrifice, dogs received 5 mCi tritiated thymidine intravenously. Irradiated and non-irradiated segments of aorta and small intestine, including intact and anastomotic regions, were analyzed for tritiated thymidine incorporation and were subjected to autoradiography. Incorporation studies showed diminution in tritiated thymidine uptake by irradiated portions of aorta and small intestine, in both intact and anastomotic regions. Autoradiograms revealed that irradiated areas of intact or anastomotic aorta or intestine had diminished labeling of stromal cells, suggesting a lowered cell proliferative capacity of irradiated tissue compared to non-irradiated portions. Inflammatory cells showed similar labeling indices in irradiated and non-irradiated tissues, both intact and surgically-manipulated, suggesting that irradiation does not significantly affect a subsequent local inflammatory response. Radiation-induced decreases in tritiated thymidine incorporation in irradiated aorta and small intestine were generally more marked at seven days than at three months following irradiation, suggesting that radiation-induced depression of cell turnover rates decreases with time. The presence of tritiated thymidine uptake after irradiation demonstrates the ability of intact and surgically-manipulated aorta and intestine to recover from radiation-induced damage.
Assuntos
Aorta Abdominal/cirurgia , Divisão Celular/efeitos da radiação , Intestino Delgado/cirurgia , Radioterapia de Alta Energia , Animais , Aorta Abdominal/efeitos da radiação , Autorradiografia , Cães , Feminino , Inflamação/etiologia , Intestino Delgado/efeitos da radiação , Período Intraoperatório , Masculino , Radioterapia/efeitos adversosRESUMO
In our clinical experience combining wide excision and intraoperative radiotherapy (IORT), five patients have developed clinical signs of lumbosacral or sciatic neuropathy within 9 months of receiving IORT to a dose of 20-25 Gy. Three patients showed recovery of nerve function over several months while two patients have shown no recovery and have near complete loss of extremity function. In an attempt to investigate this clinical observation further, the lumbosacral plexus and sciatic nerve of American foxhounds were surgically exposed and received a single dose of IORT ranging from 20-75 Gy. An approximate linear relationship between radiation dose and time to onset of hind limb paresis is found with 19 of 21 irradiated dogs showing clinical signs of nerve injury within an interval of 1-19 months. No recovery of nerve function is seen in these dogs. Histological study of the irradiated nerves demonstrates a loss of nerve fibers, particularly those of the large myelinated type without evidence of vascular occlusion or thrombosis. These studies suggest that peripheral nerve may be a dose-limiting normal tissue in clinical studies of IORT.
Assuntos
Neoplasias/radioterapia , Nervos Periféricos/efeitos da radiação , Radioterapia/efeitos adversos , Adulto , Idoso , Animais , Terapia Combinada , Cães , Feminino , Humanos , Período Intraoperatório , Masculino , Pessoa de Meia-Idade , Neoplasias/cirurgia , Traumatismos dos Nervos Periféricos , Lesões por Radiação/etiologia , Tolerância a RadiaçãoRESUMO
PURPOSE: The clinical late effects of intraoperative radiotherapy (IORT) on peripheral nerve were investigated in a foxhound model. METHODS AND MATERIALS: Between 1982 and 1987, 40 animals underwent laparotomy with intraoperative radiotherapy of doses from 0-75 Gy administered to the right lumbosacral plexus. Subsequently, all animals were monitored closely and sacrificed to assess clinical effects to peripheral nerve. This analysis reports final clinical results of all animals, with follow-up to 5 years. RESULTS: All animals treated with > or = 25 Gy developed ipsilateral neuropathy. An inverse relationship was noted between intraoperative radiotherapy dose and time to neuropathy, with an effective dose for 50% paralysis (ED50) of 17.2 Gy. One of the animals treated with 15 Gy IORT developed paralysis, after a much longer latency than the other animals. CONCLUSIONS: Doses of 15 Gy delivered intraoperatively may be accompanied by peripheral neuropathy with long-term follow-up. This threshold is less than that reported with shorter follow-up. The value of ED50 determined here is in keeping with data from other animal trials, and from clinical trials in humans.
Assuntos
Paralisia/etiologia , Nervos Periféricos/efeitos da radiação , Animais , Cães , Seguimentos , Período Intraoperatório , Doenças do Sistema Nervoso Periférico/etiologia , Doses de Radiação , Radioterapia/efeitos adversos , Fatores de TempoRESUMO
PURPOSE: The effects of intraoperative radiotherapy +/- external beam radiotherapy on prosthetic vascular grafts were investigated in a canine model. METHODS AND MATERIALS: In 1986 and 1987, 30 adult beagles underwent laparotomy with transection and segmental resection of the infrarenal aorta followed by immediate reconstruction with a prosthetic graft. Intraoperative radiotherapy at varying doses from 0-30 Gy was then administered to all animals. Half of the dogs received 36 Gy external beam radiotherapy in 10 fractions postoperatively. Animals were sacrificed and necropsied at predetermined intervals and as clinically indicated to assess early (< or = 6 months) and late (> 6 months) effects to the vascular graft and surrounding normal tissue. RESULTS: Histopathologic analyses of irradiated vascular structures were performed and correlations were made with the clinical outcome. The most frequent early clinical toxicity was graft thrombosis, occurring in 7 of 10 animals followed for < or = 6 months. Early graft thrombus formation appeared unrelated to radiotherapy dose and probably represented a technical surgical complication. Anastomotic stenosis of varying severity occurred in most animals followed > 6 months. Late (> 6 months) graft stenosis was correlated with intraoperative radiotherapy dose. At < or = 20 Gy of intraoperative irradiation, 3 of 14 animals developed late graft occlusion; at > 25 Gy, five of six animals developed late occlusion. On histopathologic review, increasing intraoperative dose and increasing total radiotherapy dose (intraoperative+external beam) appeared to correspond with increasing severity of graft changes seen after 6 months of follow-up. CONCLUSIONS: Thrombus formation is a frequent early complication of vascular graft placement of the infrarenal aorta in our beagle dog model. Intraoperative doses up to 20 Gy appear to contribute minimally to late graft occlusion, while doses > or = 25 Gy contribute to late occlusion with high likelihood. Both intraoperative dose and total radiotherapy dose correlated with late graft occlusion, and with histopathologic changes in the graft and anastomoses.
Assuntos
Aorta Abdominal/efeitos da radiação , Aorta Abdominal/cirurgia , Prótese Vascular , Cuidados Intraoperatórios , Modelos Biológicos , Animais , Aorta Abdominal/patologia , Cães , Feminino , Oclusão de Enxerto Vascular/etiologia , Lesões Experimentais por Radiação/etiologia , Tolerância a Radiação , Trombose/etiologiaRESUMO
PURPOSE: Late effects of intraoperative radiation therapy (IORT) on bladder were investigated in a canine model. METHODS AND MATERIALS: After laporatomy and cystotomy in adult female foxhounds weighing 25-35 kg, 12 MeV electrons were delivered intraoperatively to a 5 cm circular bladder field which included the trigone and both uretero-vesicle junctions. Each animal received doses of 0, 20, 25, 30, 35, or 40 Gy. All the dogs were followed 5 years postoperatively. An unoperated dog receiving no surgery or radiation treatment was followed as a control. Close clinical monitoring was performed with regular cystometrics and intravenous pyelography. Animals were killed as scheduled with complete necropsies, including histopathology, with special attention to genitourinary structures. RESULTS: There were no acute or late bladder complications detected clinically in any animal. The dog receiving 30 Gy IORT developed rhabdomyosarcoma in the treatment field at 58 months. On follow-up testing over 5 years, there was no loss of bladder contractility on cystometry, and mild changes in the ureters on intravenous pyleography when animals receiving IORT were compared with baseline pretreatment values or with control animals. Histologically, a difference was evident between irradiated and unirradiated animals, but the changes were not clearly dose-related. CONCLUSION: Intraoperative radiation therapy may by safely delivered to the canine bladder with few acute or chronic complications. It is an approach which has potential for clinical use and should continue to be explored in human clinical trials.
Assuntos
Tolerância a Radiação , Bexiga Urinária/efeitos da radiação , Animais , Cães , Relação Dose-Resposta à Radiação , Feminino , Período Intraoperatório , Radiografia , Fatores de Tempo , Bexiga Urinária/diagnóstico por imagem , Bexiga Urinária/patologia , Neoplasias da Bexiga Urinária/radioterapiaRESUMO
Tolerance of esophagus to intraoperative radiotherapy (IORT) was investigated in dogs. Thirteen adult foxhounds were subjected to right thoractomy, mobilization of the intrathoracic esophagus, and IORT to a 6 cm full-thickness esophageal segment using 9 MeV electrons at doses of 0, 2,000, or 3,000 cGy. Dogs were followed clinically and were evaluated at regular intervals after treatment with fiberoptic esophagoscopy, barium swallows, and postmortem histologic evaluations. One sham-irradiated control dog showed no abnormalities during follow-up of 24 months. Seven dogs receiving 2,000 cGy IORT showed transient mild dysphagia and mild esophagitis, but no clinically or pathologically significant complications. Five dogs receiving 3,000 cGy demonstrated severe ulcerative esophagitis within 6 weeks of treatment which progressed to chronic ulcerative esophagitis with stricture formation by 9 months following IORT. One 3,000 cGy dog died at 13 months from an esophageal perforation. On the basis of a pilot experience using 13 experimental animals, it was concluded that intact canine esophagus tolerates IORT well to doses of 2,000 cGy, but doses of 3,000 cGy pose serious and potentially lethal risks. The clinical application of IORT to the treatment of human intrathoracic neoplasms requiring esophageal irradiation should be approached with caution, particularly at doses exceeding 2,000 cGy.
Assuntos
Esôfago/efeitos da radiação , Cuidados Intraoperatórios/métodos , Radioterapia de Alta Energia , Animais , Transtornos de Deglutição/etiologia , Cães , Relação Dose-Resposta à Radiação , Esofagite/etiologia , Masculino , Tolerância a RadiaçãoRESUMO
IORT may be a potentially useful adjunctive treatment combined with surgery and/or external beam irradiation in treating locally advanced lung and esophageal tumors. To begin investigation of this modality, the tolerance of intact mediastinal structures to IORT was studied using adult American Foxhounds (wt. 25-30 kg). Groups of six animals received IORT to doses of 20, 30, or 40 Gy to two separate intrathoracic ports, using 9 MeV electrons to treat a portion of the collapsed right upper lobe, and 12 MeV electrons to treat the mediastinal structures. A group of three dogs received thoracotomy with sham irradiation. Two dogs from each treatment dose group, as well as one sham-irradiated control, were sacrificed electively at 1, 3, and 12 months following IORT. There were no acute nor late IORT related mortalities. Post-operative weight loss was minimal (average 4.5% of pre-operative weight) for all dogs. Serial esophagrams showed no inflammation or ulceration. No cardiac nor pulmonary changes were noted clinically. At autopsy, the irradiated lung showed evidence of acute pneumonitis at 1 month with progressive fibrosis at 3 months and 1 year. Esophageal reactions were minimal, with only two dogs (one 30 Gy and one 40 Gy) demonstrating histologically confirmed esophagitis at 1 month. Tracheal changes were minimal. Cardiac damage was evident in the right atrial tissues. In several dogs, this cardiac damage ranged from myocardial vascular changes to frank ischemic necrosis noted at 1 and 3 months, and dense fibrosis at 1 year. The phrenic nerves showed normal function, but had evidence of perineural fibrosis. The large vessels demonstrated only mild histologic evidence of irradiation. The results of this large animal study suggest that intact mediastinal structures will tolerate small volume IORT to doses of 20 Gy without significant clinical sequellae. Although the histologic changes in the right atrium and contralateral lung are worrisome, no cardiac nor pulmonary problems arose over the 1 year follow-up. Irradiation of the contralateral lung and other sensitive structures can be reduced by careful selection of electron beam energy and use of custom lead shielding.
Assuntos
Período Intraoperatório , Radioterapia de Alta Energia/efeitos adversos , Procedimentos Cirúrgicos Operatórios , Animais , Aorta/efeitos da radiação , Cães , Esôfago/efeitos da radiação , Feminino , Átrios do Coração/efeitos da radiação , Pulmão/efeitos da radiação , Masculino , Nervo Frênico/efeitos da radiação , Tolerância a Radiação , Traqueia/efeitos da radiaçãoRESUMO
PURPOSE: The late histopathological effects of intraoperative radiotherapy (IORT) on retroperitoneal tissues, intestine, and bile duct were investigated in dogs. METHODS AND MATERIALS: Fourteen adult foxhounds were subjected to laparotomy and varying doses (0-45 Gy) of IORT (11 MeV electrons) delivered to retroperitoneal tissues including the great vessels and ureters, to a loop of defunctionalized small bowel, or to the extrahepatic bile duct. One control animal received an aortic transection and reanastomosis at the time of laparotomy; another control received laparotomy alone. This paper describes the late effects of single-fraction IORT occurring 3-5 years following treatment. RESULTS AND CONCLUSION: Dogs receiving IORT to the retroperitoneum through a 4 x 15 cm portal showed few gross or histologic abnormalities at 20 Gy. At doses ranging from 30-45 Gy, radiation changes in normal tissues were consistently observed. Retroperitoneal fibrosis with encasement of the ureters and great vessels developed at doses > or = 30 Gy. Radiation changes were present in the aorta and vena cava at doses > or = 40 Gy. A 30 Gy dog developed an in-field malignant osteosarcoma at 3 years which invaded the vertebral column and compressed the spinal cord. A 40 Gy animal developed obstruction of the right ureter with fatal septic hydronephrosis at 4 years. Animals receiving IORT through a 5 cm IORT portal to an upper abdominal field which included a defunctionalized loop of small bowel, showed a few gross or histologic abnormalities at a dose of 20 Gy. At 30 Gy, hyaline degeneration of the intestinal muscularis layer of the bowel occurred. At a dose of 45 Gy, internal intestinal fistulae developed. One 30 Gy animal developed right ureteral obstruction and hydronephrosis at 5 years. A dog receiving 30 Gy IORT through a 5 cm portal to the extrahepatic bile duct showed diffuse fibrosis through the gastroduodenal ligament. These canine studies contribute to the area of late tissue tolerance to IORT.
Assuntos
Ductos Biliares Extra-Hepáticos/efeitos da radiação , Intestino Delgado/efeitos da radiação , Cuidados Intraoperatórios , Modelos Biológicos , Radioterapia/métodos , Ureter/efeitos da radiação , Anastomose Cirúrgica , Animais , Aorta Abdominal/efeitos da radiação , Aorta Abdominal/cirurgia , Terapia Combinada , Cães , Relação Dose-Resposta à Radiação , Laparotomia , Lesões Experimentais por Radiação/etiologia , Radioterapia/efeitos adversos , Fibrose Retroperitoneal/etiologia , Espaço Retroperitoneal/efeitos da radiação , Veia Cava Inferior/efeitos da radiaçãoRESUMO
Although studies on the control of photoperiod-related shedding by rod photoreceptors in frogs suggested that the mechanisms which initiate shedding are intrinsic features of the eye, attempts to observe light-evoked shedding in opened eye cups in balanced salt solutions have been unsuccessful. We have examined disc shedding in eye cups kept in a complex tissue culture medium. Eye cups were prepared in red light from dark-adapted animals or in white light from constant light-treated animals. Light-evoked shedding did not occur in the standard medium with -20 mM sodium bicarbonate, but a large light-evoked response was consistently seen when medium bicarbonate was raised to 030 mM. In high-bicarbonate medium, light-evoked shedding was comparable in magnitude, size distribution of phagosomes, and time course to similar responses observed in intact animals. Preliminary analysis of culture conditions which support shedding suggests that bicarbonate ion concentration is of critical importance. However, lack of light-evoked shedding in a high-bicarbonate Ringer solution suggests that some additional unidentified factor(s) in the complex medium is also necessary. The data indicate that both light- and dark-dependent processes involved in the control of photoperiod-related shedding are sustained in appropriate culture medium.
Assuntos
Bicarbonatos/farmacologia , Células Fotorreceptoras/efeitos da radiação , Animais , Adaptação à Escuridão , Técnicas In Vitro , Luz , Periodicidade , Células Fotorreceptoras/efeitos dos fármacos , Células Fotorreceptoras/fisiologia , Xenopus laevisRESUMO
BACKGROUND: Hyperthermic isolated hepatic perfusion (IHP) has been shown to cause significant regression of advanced unresectable liver metastases in patients. Although there are different agents and treatment modalities used in IHP, the contribution of perfusion hyperthermia is unknown. PURPOSE: A large animal model of unresectable liver metastases and a technical standard for IHP in this model were established. This model was used to assess the effects of hyperthermia on vascular permeability of tumors and normal liver tissue during IHP. METHODS: Sixty-five New Zealand White rabbits were used in a series of experiments. Disseminated liver tumors were established by direct injection of 1 x 10(6) VX-2 cells into the portal vein by laparotomy in anesthetized animals. Several surgical perfusion techniques were explored to determine a reliable and reproducible IHP model. Vascular permeability in tumor versus liver was then assessed with Evan's Blue labeled bovine albumin under normothermic (tissue temperature 36.5 degrees C +/- 0.5 degree C), moderate hyperthermic (39 degrees C +/- 0.5 degree C), or severe hyperthermic (41 degrees C +/- 0.5 degree C) conditions. RESULTS: Tumor model and perfusion techniques were successfully established with inflow through the portal vein and outflow through an isolated segment of the inferior vena cava. A gravity driven perfusion circuit with stable perfusion parameters and complete vascular isolation was used. Vascular permeability was higher in tumor than in normal tissues (P = .03) at all time points during IHP. Hyperthermia resulted in a significant (up to 5-fold) increase in permeability of neovasculature; when severe hyperthermia was used, tumor vascular permeability was increased even more than normal liver permeability (P = .01). CONCLUSIONS: The VX-2/New Zealand White rabbit system can be used as a reproducible large-animal model for IHP of unresectable liver metastases. It can be used to characterize the contribution and mechanism of action of different treatment parameters used in IHP. Hyperthermia preferentially increases vascular permeability in tumors compared with liver tissue in a dose-dependent fashion, thus providing a mechanism for its presumed benefit during isolated organ perfusion.
Assuntos
Permeabilidade Capilar , Hipertermia Induzida , Circulação Hepática , Neoplasias Hepáticas Experimentais/irrigação sanguínea , Neoplasias Hepáticas Experimentais/secundário , Neovascularização Patológica/metabolismo , Animais , Vasos Sanguíneos/metabolismo , Bovinos/sangue , Feminino , Hipertermia Induzida/métodos , Perfusão , Coelhos , Valores de ReferênciaRESUMO
Isolated lung perfusion with tumor necrosis factor (TNF) potentially could deliver high doses of drug and avoid systemic toxicity in patients with unresectable lung cancer or metastases. We investigated the feasibility of isolated lung perfusion with TNF in a pig model. Eleven animals had left-sided isolated lung perfusion with no TNF (n = 3), 40 micrograms/kg TNF (n = 2), 80 micrograms/kg TNF (n = 3), and 40 micrograms/kg TNF at moderate (39.5 degrees C) hyperthermia (n = 3). Hemodynamic monitoring and measurement of systemic and pulmonary circuit TNF levels were performed. Surviving animals were electively sacrificed a minimum of 6 months after isolated lung perfusion. All sham-perfused pigs survived. Isolated lung perfusion elevated pulmonary artery pressure, decreased cardiac output, and had minimal effects on mean pressure (15 +/- 0 versus 32 +/- 8 mm Hg, 4.5 +/- 1.1 versus 3.03 +/- 0.03 L/min, 67 +/- 11 versus 61 +/- 2 mm Hg; before versus after 90 minutes of isolated lung perfusion). Both 40 micrograms/kg animals and 2 of the 3 hyperthermic perfusion pigs survived, with 1 requiring pneumonectomy. Of the three 80 micrograms/kg animals, 1 survived, 1 died, and 1 required pneumonectomy. Survivors, compared with dying animals, had lower systemic/pulmonary TNF ratios and lower peak systemic TNF levels. All surviving pigs were electively sacrificed. These data justify phase I human protocols of isolated lung perfusion with TNF and hyperthermia; however, intraoperative leak rates must be monitored to ensure pulmonary isolation because systemic TNF levels may dictate treatment morbidity/mortality.
Assuntos
Quimioterapia do Câncer por Perfusão Regional , Pulmão/efeitos dos fármacos , Fator de Necrose Tumoral alfa/farmacologia , Animais , Pressão Sanguínea/efeitos dos fármacos , Bradicardia/induzido quimicamente , Débito Cardíaco/efeitos dos fármacos , Modelos Animais de Doenças , Tolerância a Medicamentos , Feminino , Frequência Cardíaca/efeitos dos fármacos , Humanos , Hipertermia Induzida , Hipotensão/induzido quimicamente , Injeções Intravenosas , Pulmão/diagnóstico por imagem , Pulmão/patologia , Oxigênio/sangue , Artéria Pulmonar , Edema Pulmonar/induzido quimicamente , Edema Pulmonar/patologia , Radiografia , Taxa de Sobrevida , Suínos , Fator de Necrose Tumoral alfa/administração & dosagem , Fator de Necrose Tumoral alfa/análise , Fator de Necrose Tumoral alfa/toxicidade , Resistência Vascular/efeitos dos fármacosRESUMO
The pressure effects of urinary reflux on renal structure and function were studied using a canine model in which the kidney was autotransplanted to the iliac fossa and the urine drained through a pyelocystostomy. This provided grade III reflux of urine (distention of the renal pelvis and calyces). A control group of nonrefluxing animals with the ureter and ureterovesical valve intact was studied in an identical fashion, and all animals were observed for one year. The reflux of sterile urine was not associated with any impairment of the inulin clearance or transport maximum of para-aminohippuric acid. There were no histologic abnormalities of glomeruli, tubules, or interstitium noted in the animals exposed to sterile reflux, nor were any differences found between the study and control groups. The transmission of bladder pressures into the renal pelvis and calyces during reflux is considered an unimportant factor in explaining the renal damage noted from sterile reflux of short duration in adults. The pyelocystostomy provides a satisfactory means of urinary drainage, and may be used effectively to study the properties of urinary reflex.
Assuntos
Modelos Animais de Doenças , Rim/fisiopatologia , Refluxo Vesicoureteral/fisiopatologia , Animais , Cães , Feminino , PressãoRESUMO
The effects of denervation upon the Meissner corpuscle were evaluated by sequential fingertip biopsies in 3 rhesus monkeys, following transection of all the sensory innervation of the hand. Histological techniques were used to identify changes in the neural, connective, and enzymatic components of the Meissner corpuscles. Denervation of the Meissner corpuscle resulted in rapid and complete degeneration of the axon terminal and a slowly progressive degeneration of the connective tissue component of the corpuscle, characterized by loss of lobulation, lamellar collapse, and a steadily diminishing corpuscular size. The physiological basis and the clinical implications of these findings are discussed. The literature is reviewed.
Assuntos
Denervação , Plexo Submucoso/patologia , Animais , Biópsia , Feminino , Macaca mulatta , Microscopia Eletrônica , Degeneração Neural , Coloração e RotulagemRESUMO
PIP: China's principle of self-reliance appears to have 4 sources: 1) having known the pain of dependence in the period of the Manchu Dynasty's encounter with the West, the Chinese are determined to be totally independent; 2) self-reliance appears to be related to China's long tradition of cultural self-containment; 3) a key tenet of Marxism to which history and culture pushed Mao is that internal factors are always decisive in a country's affairs; and 4) objective facts of China's great size and agricultural economy have made self-reliance in part the rationalization of necessity. The first 3 of these 4 sources of the principle of self-reliance are not immutable. In fact, self-reliance is being severely modified economically and politically, although not as yet militarily. China's trade with the world increased markedly in value during the 1970s, from U.S. $3.86 billion in 1969 to about U.S. $15 billion in 1975. A certain institutionalization of the country's international economic involvement also seems to be taking place. Behind all these developments is an apparent rejection of strict self-reliance in the sense of buying only what cannot be made and selling only waht is left over in favor of tentative acceptance of the law of comparative advantage in international economic relationships. On the political level a certain acceptance of an interdependent world is evident. The Chinese leadership, however has not been compltely united on these departures from self-reliance. Certain specific natural and socio-political factors that bear on the fate of self-reliance are identified. The 4th source of self-reliance--objective facts of China's size and agricultural character--appears the most persistent and will continue to be the major constraint against any clear-cut abandonment of self-reliance.^ieng
Assuntos
Comunismo , Economia , Organização e Administração , Sistemas Políticos , Política , Política Pública , Planejamento Social , Ásia , China , Países em Desenvolvimento , Ásia Oriental , Crescimento Demográfico , SocialismoRESUMO
Chronic wrist pain can be frustrating for the hand surgeon. The most critical portion of the evaluation is the history and physical examination, which will lead to the various diagnostic modalities available. Table 2 is a summary of some of the more common tests and their uses. Wrist arthroscopy is one of the more useful tools available to the hand surgeon, being both diagnostic and therapeutic. The algorithms developed in this paper are by no means exhaustive or all encompassing. Rather they should be viewed as a guide to assist the hand surgeon in the treatment of these difficult problems.