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Results for “in vivo experiments”

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At least 19 recordsLinked to original sources

PubMed1984

Laser myoplasty for hypertrophic cardiomyopathy. In vitro experience in human postmortem hearts and in vivo experience in a canine model (transarterial) and human patient (intraoperative).

The feasibility of performing a myotomy/myectomy for hypertrophic cardiomyopathy (HC) by means of laser phototherapy was evaluated experimentally in vitro and in vivo, and the procedure then applied to a patient intraoperatively. In vitro experience revealed that the beam of an argon laser, delivered directly or via an optical fiber, could both cut and vaporize myocardium, producing a myotomy/myectomy morphologically similar to that produced by the conventional blade technique. In vivo experiments, in which the beam of an argon laser was delivered via an optical fiber to the ventricular septum of a canine heart, confirmed that a laser myoplasty could be achieved in 4 of 5 dogs by a transarterial approach. Finally, laser myoplasty was performed intraoperatively in a patient with HC, using a 200-mu fiber interfaced with an argon laser. Measured laser power was 1.5 W; cumulative exposure was less than 4 minutes; the myoplasty was 4 X 1 X 0.5 cm. These investigations establish the feasibility of using laser therapy to create a myoplasty trough that is similar in appearance to that typically achieved by the conventional blade technique. Illumination of the intraventricular operative field and precise modeling of the myoplasty trough constitute the principal advantages of laser myoplasty for HC.

Adult↗

PubMed2006

Pathway-specific trafficking of native AMPARs by in vivo experience.

An accumulating body of evidence supports the notion that trafficking of AMPA receptors (AMPARs) underlies strengthening of glutamatergic synapses and, in turn, learning and memory in the behaving animal. However, without exception, these experiments have been performed using artificial stimulation protocols, cultured neurons, or viral-overexpression systems that can significantly alter the normal function of AMPARs. Using a single-whisker experience protocol that significantly enhances neuronal responses in vivo, we have targeted neurons in and around the spared whisker column of fosGFP transgenic mice for whole-cell recording. Here we show that in vivo experience induces the pathway-specific strengthening of neocortical excitatory synapses. By assaying AMPARs for rectification and sensitivity to joro spider toxin, we find that in vivo experience induces the delivery of native GluR2-lacking receptors at spared, but not deprived, inputs. These data demonstrate that pathway-specific trafficking of GluR2-lacking AMPARs is a normal feature of synaptic strengthening that underlies experience-dependent plasticity in the behaving animal.

Analysis of Variance↗

PubMed1986

[Effect of types of field used in nuclear magnetic resonance tomography on core and surface temperature in the human body. Results of in vitro and in vivo experiments].

Deep and superficial body temperature was measured by in vitro and in vivo experiments, using a fluoro-optic procedure and a variety of magnetic and electromagnetic fields in the course of magnetic resonance tomography. The in vitro experiments had shown that measured temperature changes resulting from a static magnetic field were reversible and could be reproduced readily. Temperature measurements in the human body were carried out centrally (oesophageal and rectal measurements) and at the periphery (intravascular). In vivo experiments on 30 experimental subjects showed no significant changes (p = 0.05) in central or surface temperatures as a result of static or dynamic magnetic fields or electromagnetic high frequency fields.

Body Temperature↗

PubMed2026

Validation of the Mechanism of Action of Jiedu Shengji Oil in the Treatment of Radiation Dermatitis based on Network Pharmacology and In vivo Experiments.

BACKGROUND: Radiation Dermatitis (RD) is a common complication of radiation therapy, with approximately 90% of patients experiencing moderate to severe radiation dermatitis injury after radiotherapy. Jiedu Shengji oil (JDSJY) is a commonly used herbal topical preparation in our hospital, with remarkable clinical efficacy in treating radiation dermatitis. However, the mechanism of JDSJY in treating RD is unclear. AIMS: The aim of the study is to explore JDSJY's mechanism of action in treating RD through methods, such as network pharmacology and in vivo experiments. METHODS: The active components and disease targets of JDSJY were screened and intersected via network pharmacology for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. The pharmacodynamics of JDSJY was evaluated by establishing a rat model of RD. RESULTS: Network pharmacology showed that the pathway network of JDSJY action involved 64 targets and 6 pathways and might act by targeting key targets, such as C-reactive protein (CRP) and regulating the MAPK signalling pathway. In addition, in vivo experiments showed that JDSJY reduced skin inflammation and inhibited apoptosis, significantly ameliorated mitochondrial damage in keratinocytes, and reduced the levels of antioxidant-related indicators. CONCLUSION: Comprehensive network pharmacology and in vivo experiments revealed that JDSJY's therapeutic efficacy in RD is mediated by ameliorating oxidative stress and maintaining mitochondrial homeostasis in keratinocytes.

Animals↗

PubMedDate not supplied

[Interferon induction by lacticacid bacteria in vitro and in vivo experiments].

Interferonogenic acitivity of lacticacid bacteria was studied in experiments in vitro and in vivo. It have been shown, that interferon induction depends both on strain species and on culture medium used for lactobacteria harvesting. Streptococcus thermophilus induces interferon more actively in leucocytes (in vitro)--1280 AU/ml on the bines broth medium, and less actively--320 AU/ml on fermented corn medium. Interferon induction in human leucocytes was not registered in case of L. plantarum 200 strain. In vivo experiments show that E. faecium strain and strain mixture of streptococcus termophilus are active interferon inductors. Induced interferon is recognized as alpha- and gamma-interferon, with domination of alpha-interferon.

Cells, Cultured↗

PubMed1996

In vivo visualization of hippocampal cells and dynamics of Ca2+ concentration during anoxia: feasibility of a fiber-optic plate microscope system for in vivo experiments.

The feasibility of a fiber-optic plate (FOP) microscope system employing a bundle of optical fibers and videomicroscopy for in vivo experiments was investigated. The FOP used here consisted of optical fibers 3 microns in diameter. By inserting the FOP into an animal, optical signals from the deep-lying tissue invisible from the surface could be obtained as two-dimensional images. Using this system, hippocampal cells stained with a fluorescent dye in an anesthetized rat were visualized. Elevation of intracellular free calcium concentration ([Ca2+]i) in the hippocampus of the rat during anoxic exposure was also detected with a fluorescent indicator dye. These results showed that the FOP microscope system was sufficiently applicable to in vivo experiments for studying tissue structure and physiological activity even in the deep regions with fluorometric techniques.

Animals↗

PubMed1986

[In vivo experiments, in vitro assays in experimental oncology: establishment of LA 795 Vv-Vt].

In vivo experiment, in vitro assays (in vivo-in vitro system) is a kind of experimental technique which is different from both in vitro cell line and tumor line. The new model can be grown and studied either as an animal tumor or a cell culture. The specimen could be assayed for cell survival in vitro. This model can be used to study the response of malignant cells to the treatment in a precision and depth that is impossible in tumors grown in vivo. LA 795 Vv-Vt is the first in vivo-in vitro system developed in China. It was established with lung adenocarcinoma of T-739 mouse. The tumor cells could grow freely both in vivo and in vitro with a plating efficiency of 20%. Characteristics of LA 795 Vv-Vt tumor and cell in culture were described and compared. In order to estimate the radiation response of different doses, cell survival curves of tumors irradiated under oxic and hypoxic conditions were drawn and compared. The oxygen enhance ratio was 2.98. The experiments indicate that in vivo-in vitro system has a good dependent relation in dose and effect and is worth extensive application.

Adenocarcinoma↗

PubMed2006

Intraoperative radiofrequency ablation using a loop internally cooled-perfusion electrode: in vitro and in vivo experiments.

OBJECTIVE: We sought to validate the efficiency of intraoperative radiofrequency ablation (RFA) using a prototype loop internally cooled-perfusion (LICP) electrode to induce coagulation in the subcapsular portion of the liver. MATERIALS AND METHODS: In in vitro experiments, 30 ablation regions were created using a 200-W generator and a LICP electrode featured simultaneous intraelectrode cooling and continuous flow of hypertonic saline along the shaft in explanted bovine liver. In the in vivo experiments, 26 ablation zones were created according to one of the five protocols in 10 dogs: group A, RFA using a cooled-tip electrode (n = 6); group B, RFA using a LICP electrode with 2 cm loop tip (n = 6); group C, RFA using a LICP electrode with a 3-cm loop tip (n = 6); group D, RFA using a cooled-tip electrode and Pringle maneuver (n = 4); and group E, RFA using a LICP electrode with 2 cm loop tip and Pringle maneuver (n = 4). The dimensions of the coagulation parameters were compared between the groups. RESULTS: In the in vitro experiments, RFA using a 2- or 3-cm diameter LICP electrode (3.6 +/- 0.3 cm, 3.4 +/- 0.5 cm, respectively) created deeper dimensions of coagulation than did a 4-cm electrode (2.3 +/- 0.2 cm; P < 0.05). In the in vivo experiments, the RFA using the LICP electrodes in porcine liver with normal perfusion induced wider but superficial ablation regions when compared to standard RFA using an internally cooled electrode (P < 0.05). However, using a Pringle maneuver, RFA with a LICP electrode created a larger volume of ablation area when compared to RFA using an internally cooled electrode with a similar range of axial diameter along the electrode axis: 30.0 +/- 6.1 cm3 (group D) versus 68.5 +/- 14.0 cm3 (group E; P < 0.05) CONCLUSIONS: Intraoperative RFA using the LICP electrode induced a well-defined semicircular coagulation with a 3.5-cm axial diameter in the subcapsular region of the liver. This device appears to be promising for the treatment of superficial tumors during intraoperative RFA.

Animals↗

PubMed1986

In vivo experiments with the excimer laser--technical parameters and healing processes.

In vivo experiments on rabbit corneae with the excimer laser (lambda = 193 nm) are presented. A new delivery system using total-reflecting prisms is described. For corneal surgery a repetition rate of about 50 Hz seems to be optimal. Healing processes of the cornea are demonstrated. It is supposed that the corneal incisions by excimer laser have not to be as deep as those induced by knives to change corneal curvature.

Animals↗

PubMed1982

Effects of dilazep on fibrinolytic system in animals. I. Enhancement of fibrinolytic activity by administered dilazep in ex vivo experiment.

The effects of dilazep on blood fibrinolytic system were studied in ex vivo experiment. Fibrinolytic activity in plasma was determined by the fibrin plate method at designed times after the administration of dilazep in guinea pigs, rabbits and mongrel dogs. In guinea pigs, fibrinolytic activity of euglobulin (plasminogen activator level, 1.10+/-0.08 CU/ml in control animals) rose to 1.53+/-0.24, 1.92+/-0.13 and 2.35+/-0.15 CU/ml 2 h after the p.o. administration of 30, 100 and 300 mg/kg of dilazep, respectively. Plasminogen levels in euglobulin were unchanged, however, plasmin inhibitory activities were lowered following the increase of plasminogen activator levels. About 2-fold increase of plasminogen activator level was also observed in rabbits 60 min after the p.o. administration of 300 mg/kg dilazep and returned to the initial level (0.054 CU/ml) within 3 h after the administration. A rapid increase of plasminogen activator level was observed in a case of the i.v. administration of dilazep into rabbits and mongrel dogs. In in vitro experiment, dilazep added to whole blood or plasma of guinea pigs ranging 0.1 to 1000 microgram/ml did not reveal any effects on plasminogen activator level or plasmin inhibitory activity in plasma.

Animals↗

PubMed2003

Initial in vivo experience with steady-state subzone-based MR elastography of the human breast.

PURPOSE: To describe initial in vivo experiences with a subzone-based, steady-state MR elastography (MRE) method. This sparse collection of in vivo results is intended to shed light on some of the strengths and weaknesses of existing clinical MRE approaches and to indicate important areas of future research. MATERIALS AND METHODS: Elastic property reconstruction results are compared with data compiled from the limited existing body of published studies in breast elasticity. Mechanical parameter distributions are also investigated in terms of their implications for the nature of biological soft tissue. Additionally, a derivation of the statistical variance of the elastic parameter reconstruction is given and the resulting confidence intervals (CIs) for different parameter solutions are examined. RESULTS: By comparison with existing estimates of the elastic properties of breast tissue, the subzone-based, steady-state MRE method is seen to produce reasonable estimates for the mechanical properties of in vivo tissue. CONCLUSION: MRE shows potential as an effective way to determine the elastic properties of breast tissue, and may be of significant clinical interest.

Adipose Tissue↗

PubMed1987

Verification of theoretical modeling of heat transmission in teeth by in vivo experiments.

A theoretical axisymmetric tooth model, simulating the conditions involved in the drinking of a liquid of a certain temperature, was compared with results of a similar in vivo experiment. The temperature changes as a result of one draught of a hot/cold liquid were recorded within the model as well as in the surrounding environment. The experimental data obtained were compared with the calculated results for the theoretical model as determined by the Finite Element Analysis. The temperatures recorded experimentally agreed reasonably with the calculated results. It can be concluded that the assumptions which have been made concerning the described thermal loading conditions lead to a good approximation of the physical reality.

Cold Temperature↗

PubMed1993

Urethral function after cystectomy: a canine in vivo experiment.

To study the function of the pelvic floor and the isolated urethra after removal of the bladder, 5 male and 5 female mongrel dogs were used in an acute in vivo experiment. Urethral pressure changes secondary to unilateral stimulation of the pelvic and pudendal nerves were recorded. After baseline data of the intact system were documented, the following procedures were carried out: separation of the urethra from the bladder neck (prostate), nerve-sparing cystectomy (cystoprostatectomy), and cold-knife incision through the entire length of the proximal urethra. Pressure recordings were repeated after each step of surgery. Pudendal nerve stimulation resulted in rapid and large pressure rises in the distal urethra (reaction typical of striated muscle). This response remained unchanged after all three surgical steps. Pelvic nerve stimulation provoked pressure rises within the urethra of a pattern typical of smooth muscle. The findings persisted after separation of the urethra from the bladder neck (prostate) and after cystectomy, but were not observed after urethrotomy. Contractions secondary to pudendal nerve stimulation were inhibited by curare, which did not affect the reaction to pelvic nerve stimulation. Our experiments demonstrate that in the dog the continuity of bladder and urethra is not required for the function of urethral closure mechanisms. The contractile potency of the urethral smooth muscles remains intact after nerve-sparing cystectomy. We believe that problems with the baseline continence of surrogate bladders should mainly be ascribed to a lack of surgical caution in preserving the autonomic nerves of cystectomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1997

Radiofrequency interstitial tumor ablation (RITA) is a possible new modality for treatment of renal cancer: ex vivo and in vivo experience.

Small renal tumors are increasingly diagnosed and are frequently treated by nephron-sparing surgery. Tumors can be ablated by radiofrequency (RF) energy, which allows the operator to create very localized necrotic lesions. Radiofrequency interstitial tumor ablation (RITA) has been used in human kidneys in an ex vivo experiment to assess the necrotic lesions produced in a model close to physiologic conditions and then in three patients with localized renal cancer prior to radical nephrectomy. In the ex vivo model, four freshly removed kidneys were treated. Bipolar RF energy was delivered by a generator connected to two needles introduced parallel to each other into the renal parenchyma. A thermocouple was inserted between the two active electrodes. The renal artery at physiologic conditions was maintained at a constant temperature of perfusion of 37 degrees C by a computer-assisted Hot-line monitor. Two lesions were produced in each pole of each kidney including the cortex and the medulla. In an initial human study focusing on safety, feasibility, and pathology, three patients were treated by RITA with bipolar and monopolar energy. One patient with a peripheral 2-cm upper-pole tumor was treated percutaneously under ultrasound guidance with local anesthesia only 1 week prior to surgery. The other patients, with 3- and 5-cm tumors, were treated during surgery under general anesthesia just before nephrectomy. Ex vivo, the maximum temperature at the active needles ranged from 84 degrees C to 130 degrees C with 10 to 14 W applied during 10 to 14 minutes. Lesions were on average 2.2 x 3 x 2.5 cm.3 Microscopic examination showed stromal edema with intensive pyknosis. No damage was seen to adjacent untreated tissue. In the in vivo procedure, tolerance of RTA as an anesthesia-free procedure was excellent. The size of the observed lesions was comparable to the forecast size depending on the needle deployment. No side effects were noted, and no adjacent structures were affected by the RF ablation. These preliminary studies demonstrate the ability of RITA to produce localized extensive necrosis in kidney parenchyma and tumors safely under local anesthesia. Further studies could evaluate this new minimally invasive treatment in small kidney tumors considered for nephron-sparing surgery.

Aged↗

PubMed1990

[Adhesion of liners to dentin. In vivo experiments].

Research was performed in vivo on 42 vital teeth. Cavities of I and V Class where made, than restored with glass ionomer liners and composites. The teeth were extracted, stained and sectioned. Optic microscope did not show any stain under the ionomer liner, even in cases where composites were infiltrated. Electron microscope did not show any gap between ionomer liner and dentin.

Adhesiveness↗

PubMed1995

Dissociation of tissue thiols content from nitroglycerin-induced cyclic-3',5'-guanosine monophosphate and the state of tolerance: in vivo experiments in rats.

The in vivo effects of nitroglycerin (GTN) on the biochemical response [cyclic-3',5'-guanosine monophosphate (cGMP) levels] of vascular (aorta and inferior vena cava, IVC) and other tissues (heart and lung) were studied. GTN caused dose and time-dependent increases in cGMP content of aorta and IVC. Compared to base line, maximal concentrations of 3- to 4-fold the basal levels of cGMP were measured in the aorta, IVC and lung of rats after 2 mg i.v. bolus doses of GTN. Tolerance to GTN, as assessed by the reduction in the cGMP increase in response to an i.v. GTN dose, developed 12 to 18 hr after continuous i.v. infusion (100-200 micrograms/hr) of the drug. Significant differences in the pattern of formation and degradation of cGMP were noted between tolerant and nontolerant rats. Unlike the control IVC tissue, where elevated cGMP was measured throughout the 5-min post GTN administration, in tolerant IVC, cGMP levels were not significantly different from the basal values at time points 3 and 5 min post GTN. These results suggest that IVC is more prone to (or less recoverable from) the state of tolerance than the aorta. Furthermore, when tissue thiols were measured in control and tolerant rats, a complete dissociation was observed between the state of tolerance and the endogenous glutathione and cysteine concentrations. These data constitute strong evidence against an in vivo depletion of tissue thiols as being the primary determinant underlying the development of tolerance during nitrate therapy.

Animals↗

PubMedDate not supplied

[Size and shape of commercially available polyethylene particles for in-vitro and in-vivo-experiments].

AIM: The longevity of total hip arthroplasty is sometimes limited by osteolysis and aseptic loosening. Aseptic loosening may be caused by the biologic reaction to polyethylene wear particles. Particles of less than 1 micro m diameter are of particular importance. These particles are not easily available for experimental use. METHOD: We performed a morphologic analysis of commercially available, very small polyethylene particles (Ceridust(R)) in order to determine the specific size distribution. We measured 1 978 particles. Size analysis was performed using an electron microscope. Particle size was described as the equivalent circle diameter (ECD). Particle morphology was described as feret ratio. In addition, Ceridust(R) particles were compared to different particles stemming from a hip simulator experiment. RESULTS: More than 35 % of the particles were less than 1 micro m in size. The particle size was 1.75 micro m +/- 1.43 micro m (median 1.42 micro m). The minimum was 0.06 micro m, the maximum was 11.06 micro m. The feret ratio was 0.58 +/- 0.17 (median 0.63). The minimum was 0.07, the maximum was 0.93. The majority of Ceridust(R) particles had a rough surface. Compared to polyethylene particles stemming from a hip simulator experiment, Ceridust(R) particles had a rougher surface, were less longitudinal, and had a more even size distribution. CONCLUSIONS: The pure, commercially available polyethylene particles analyzed here are suitable for in vitro and in vivo experiments due to their easy availability, minor costs, and large fraction of very small particles.

Biocompatible Materials↗

PubMed1992

IMOCUR stimulates production of immunoglobulins; preliminary results concerning a correlation between in vitro and in vivo experiments.

The bacterial extract IMOCUR is described as an in vivo stimulant of antibody production during animal testing and human clinical trials. Using a slightly modified procedure (13) dealing with in vitro immunoglobulin production by C57B1/6 mouse spleen cells, we have shown that IMOCUR potentiates spontaneous IgM production. In order to explore the putative relation between this in vitro activity and the current in vivo control test (stimulation of plaque-forming cell production after sheep red blood cell injection to Balb/c mouse), we have assayed 10 lyophilisates in vitro and in vivo before and after heat inactivation (80 degrees C, 7 days in a saturated water atmosphere). Results have shown that this treatment inhibits, respectively, totally and partially in vivo and in vitro activities. Thus the in vitro technique seems to be appropriate for the control of activity of the various batches of IMOCUR. Experiments are under way to clarify the mathematical correlation which may exist between the in vitro and in vivo experiments.

Adjuvants, Immunologic↗