Detection of dentinal cracks after root-end resection: an ex vivo study comparing microscopy and endoscopy with scanning electron microscopy

Dentinal cracks are occasionally observed at the cut root face after root-end resection in apical surgery. The objective of this ex vivo study was to evaluate and compare the efficiency of visual aids to identify root-end dentinal cracks.

Steerable intravitreal inserts for drug delivery: in vitro and ex vivo mobility experiments

The progress of wet age-related macular degeneration can now be controlled by intravitreal drug injection. This approach requires repeated injections, which could be avoided by delivering the drug to the retina. Intraocular implants are a promising solution for drug delivery near the retina. Currently, their accurate placement is challenging, and they can only be removed after a vitrectomy. In this paper, we introduce an approach for minimally invasive retinal drug delivery using magnetic intraocular inserts. We briefly discuss the electromagnetic-control system for magnetic implants and then focus on evaluating their ability to move in the vitreous humor. The mobility of magnetic intraocular implants is estimated in vitro with synthesized vitreous humors, and ex vivo with experiments on cadaver porcine eyes. Preliminary results show that with such magnetic implants a vitrectomy can be avoided.

Impact of corneal cross-linking on drug penetration in an ex vivo porcine eye model

To analyze the influence of corneal cross-linking (CXL) using ultraviolet-A and riboflavin on corneal drug penetration of topically applied drugs.

Effect of topical anesthetic agents and ethanol on corneoepithelial wound healing in an ex vivo whole-globe porcine model

To assess the impact of topical anesthetic agents and ethanol on ocular surface wound healing using an ex vivo whole-globe porcine model.

Effects of Echinaforce® treatment on ex vivo-stimulated blood cells

The herb Echinacea purpurea, also called purple coneflower, is regarded as an immune modulator. This study examined changes in cytokine production in blood samples from 30 volunteers before and during 8-day oral administration with an ethanolic extract of fresh Echinacea purpurea (Echinaforce(®)). Daily blood samples were ex vivo stimulated by LPS/SEB or Zymosan and analysed for a series of cytokines and haematological and metabolic parameters. Treatment reduced the proinflammatory mediators TNF-α and IL-1β by up to 24% (p<0.05) and increased anti-inflammatory IL-10 levels by 13% (p<0.05) in comparison to baseline. This demonstrated a substantial overall anti-inflammatory effect of Echinaforce(®) for the whole group (n=28). Chemokines MCP-1 and IL-8 were upregulated by 15% in samples from subjects treated with Echinaforce(®) (p<0.05). An analysis of a subgroup of volunteers who showed low pre-treatment levels of the cytokines MCP-1, IL-8, IL-10 or IFN-γ (n=8) showed significant stimulation of these factors upon Echinaforce(®) treatment (30-49% increases; p<0.05), whereas the levels in subjects with higher pre-treatment levels remained unaffected. We chose the term "adapted immune-modulation" to describe this observation. Volunteers who reported high stress levels (n=7) and more than 2 colds per year experienced a significant transient increase in IFN-γ upon Echinaforce(®) treatment (>50%). Subjects with low cortisol levels (n=11) showed significant down-regulation of the acute-phase proteins IL1-β, IL-6, IL-12 and TNF-α by Echinaforce(®) (range, 13-25%), while subjects with higher cortisol levels showed no such down-regulation. This is the first ex vivo study to demonstrate adapted immune-modulation by an Echinacea preparation. While Echinaforce(®) did not affect leukocyte counts, we speculate that the underlying therapeutic mechanism is based on differential multi-level modulation of the responses of the different types of leukocytes. Echinaforce(®) thus regulates the production of chemokines and cytokines according to current immune status, such as responsiveness to exogenous stimuli, susceptibility to viral infection and exposure to stress.

Prospective ex-vivo study on thermal effects in human skin phototypes II, IV and VI: a comparison between the 808, 1064, 1210 and 1320-nm diode laser

Laser Assisted Skin Healing (LASH) was first introduced in 2001 by Capon and Mordon to prevent keloids and hypertrophic scars. LASH requires homogenous heating throughout the full thickness of the skin around the wound. However, LASH therapy with 808-nm diode laser is deemed to be only applicable for phototype I-IV due to melanin absorption. This prospective ex-vivo study aims to evaluate the thermal effects of different wavelengths (808, 1064, 1210 and 1320 nm) on human skin phototype II, IV and VI.

Underneath the cerclage: an ex vivo study on the cerclage-bone interface mechanics

Cerclages regain interest due to a rising number of periprosthetic fractures. The contact distribution at the circumferential cerclage-bone interface is still unknown. Local interface pressure depends on the amount of contact area. Cortical damage at the interface would provoke cerclage loosening. Therefore, the contact area, the bone pressure along the interface and the cortical resistance underneath loaded cerclages were determined in an ex vivo model.

Distribution of radiodense contrast medium after perineural injection of the palmar and palmar metacarpal nerves (low 4-point nerve block): an in vivo and ex vivo study in horses

REASONS FOR PERFORMING STUDY: Evidence-based information is limited on distribution of local anaesthetic solution following perineural analgesia of the palmar (Pa) and palmar metacarpal (PaM) nerves in the distal aspect of the metacarpal (Mc) region ('low 4-point nerve block'). OBJECTIVES: To demonstrate the potential distribution of local anaesthetic solution after a low 4-point nerve block using a radiographic contrast model. METHODS: A radiodense contrast medium was injected subcutaneously over the medial or the lateral Pa nerve at the junction of the proximal three-quarters and distal quarter of the Mc region (Pa injection) and over the ipsilateral PaM nerve immediately distal to the distal aspect of the second or fourth Mc bones (PaM injection) in both forelimbs of 10 mature horses free from lameness. Radiographs were obtained 0, 10 and 20 min after injection and analysed subjectively and objectively. Methylene blue and a radiodense contrast medium were injected in 20 cadaver limbs using the same techniques. Radiographs were obtained and the limbs dissected. RESULTS: After 31/40 (77.5%) Pa injections, the pattern of the contrast medium suggested distribution in the neurovascular bundle. There was significant proximal diffusion with time, but the main contrast medium patch never progressed proximal to the mid-Mc region. The radiological appearance of 2 limbs suggested that contrast medium was present in the digital flexor tendon sheath (DFTS). After PaM injections, the contrast medium was distributed diffusely around the injection site in the majority of the limbs. In cadaver limbs, after Pa injections, the contrast medium and the dye were distributed in the neurovascular bundle in 8/20 (40%) limbs and in the DFTS in 6/20 (30%) of limbs. After PaM injections, the contrast and dye were distributed diffusely around the injection site in 9/20 (45%) limbs and showed diffuse and tubular distribution in 11/20 (55%) limbs. CONCLUSIONS AND POTENTIAL RELEVANCE: Proximal diffusion of local anaesthetic solution after a low 4-point nerve block is unlikely to be responsible for decreasing lameness caused by pain in the proximal Mc region. The DFTS may be penetrated inadvertently when performing a low 4-point nerve block.

Ex vivo assessment of chemotherapy-induced apoptosis and associated molecular changes in patient tumor samples

BACKGROUND: There are inherent conceptual problems in investigating the pharmacodynamics of cancer drugs in vivo. One of the few possible approaches is serial biopsies in patients. However, this type of research is severely limited by methodological and ethical constraints. MATERIALS AND METHODS: A modified 3-dimensional tissue culture technique was used to culture human tumor samples, which had been collected during routine cancer operations. Twenty tumor samples of patients with non-small cell lung cancer (NSCLC) were cultured ex vivo for 120 h and treated with mitomycin C, taxotere and cisplatin. The cytotoxic activity of the anticancer agents was quantified by assessing the metabolic activity of treated tumor cultures and various assays of apoptosis and gene expression were performed. RESULTS: The proliferative activity of the tissue was maintained in culture as assessed by Ki-67 staining. Mitomycin C, cisplatin and taxotere reduced the metabolic activity of the tumor tissue cultures by 51%, 29% and 20%, respectively, at 120 h. The decrease in metabolic activity corresponded to the induction of apoptosis as demonstrated by the typical morphological changes, such as chromatin condensation and nuclear fragmentation. In addition, activated caspase-3 could be verified in apoptotic cells by immunohistochemistry. To verify functional aspects of apoptosis, the induction of chemotherapy-induced cell death was inhibited with the caspase inhibitor z-VAD.fmk. RNA was extracted from the tissue cultures after 120 h of ex vivo drug treatment and was of sufficient quality to allow quantitative PCR. CONCLUSION: The 3-dimensional ex vivo culture technique is a useful method to assess the molecular effects of pharmacological interventions in human cancer samples in vitro. This culture technique could become an important tool for drug development and for the prediction of in vivo drug efficacy.

Establishment of a novel intervertebral disc/endplate culture model: analysis of an ex vivo in vitro whole-organ rabbit culture system

STUDY DESIGN: Ex vivo in vitro study evaluating a novel intervertebral disc/endplate culture system. OBJECTIVES: To establish a whole-organ intervertebral disc culture model for the study of disc degeneration in vitro, including the characterization of basic cell and organ function. SUMMARY OF BACKGROUND DATA: With current in vivo models for the study of disc and endplate degeneration, it remains difficult to investigate the complex disc metabolism and signaling cascades. In contrast, more controlled but simplified in vitro systems using isolated cells or disc fragments are difficult to culture due to the unconstrained conditions, with often-observed cell death or cell dedifferentiation. Therefore, there is a demand for a controlled culture model with preserved cell function that offers the possibility to investigate disc and endplate pathologies in a structurally intact organ. METHODS: Naturally constrained intervertebral disc/endplate units from rabbits were cultured in multi-well plates. Cell viability, metabolic activity, matrix composition, and matrix gene expression profile were monitored using the Live/Dead cell viability test (Invitrogen, Basel, Switzerland), tetrazolium salt reduction (WST-8), proteoglycan and deoxyribonucleic acid quantification assays, and quantitative polymerase chain reaction. RESULTS: Viability and organ integrity were preserved for at least 4 weeks, while proteoglycan and deoxyribonucleic acid content decreased slightly, and matrix genes exhibited a degenerative profile with up-regulation of type I collagen and suppression of collagen type II and aggrecan genes. Additionally, cell metabolic activity was reduced to one third of the initial value. CONCLUSIONS: Naturally constrained intervertebral rabbit discs could be cultured for several weeks without losing cell viability. Structural integrity and matrix composition were retained. However, the organ responded to the artificial environment with a degenerative gene expression pattern and decreased metabolic rate. Therefore, the described system serves as a promising in vitro model to study disc degeneration in a whole organ.

A technique to detect and to quantify fasciocutaneous blood vessels in small laboratory animals ex vivo

PURPOSE: A microangiographical technique is described, which allows visualization of small and capillary blood vessels and quantification of fasciocutaneous blood vessels by means of digital computer analysis in very small laboratory animals. MATERIALS AND METHODS: The left carotid artery of 20 nu/nu mice was cannulated (26 gauge) and a mixture of gelatin, bariumsulfate, and green ink was injected according to standardized protocol. Fasciocutaneous blood vessels were visualized by digital mammography and analyzed for vessel length and vessel surface area as standardized units [SU] by computer program. RESULTS: With the described microangiography method, fasciocutaneous blood vessels down to capillary size level can be clearly visualized. Regions of interest (ROIs) can be defined and the containing vascular network quantified. Comparable results may be obtained by calculating the microvascular area index (MAI) and the microvascular length index (MLI), related to the ROIs size. Identical ROIs showed a high reproducibility for measured [SU] < 0.01 +/- 0.0012%. CONCLUSION: Combining microsurgical techniques, pharmacological knowledge, and modern digital image technology, we were able to visualize small and capillary blood vessels even in small laboratory animals. By using our own computer analytical program, quantification of vessels was reliable, highly reproducible, and fast.

Tolerance of human placental tissue to severe hypoxia and its relevance for dual ex vivo perfusion

In the dual ex vivo perfusion of an isolated human placental cotyledon it takes on average 20-30 min to set up stable perfusion circuits for the maternal and fetal vascular compartments. In vivo placental tissue of all species maintains a highly active metabolism and it continues to puzzle investigators how this tissue can survive 30 min of ischemia with more or less complete anoxia following expulsion of the organ from the uterus and do so without severe damage. There seem to be parallels between "depressed metabolism" seen in the fetus and the immature neonate in the peripartum period and survival strategies described in mammals with increased tolerance of severe hypoxia like hibernators in the state of torpor or deep sea diving turtles. Increased tolerance of hypoxia in both is explained by "partial metabolic arrest" in the sense of a temporary suspension of Kleiber's rule. Furthermore the fetus can react to major changes in surrounding oxygen tension by decreasing or increasing the rate of specific basal metabolism, providing protection against severe hypoxia as well as oxidative stress. There is some evidence that adaptive mechanisms allowing increased tolerance of severe hypoxia in the fetus or immature neonate can also be found in placental tissue, of which at least the villous portion is of fetal origin. A better understanding of the molecular details of reprogramming of fetal and placental tissues in late pregnancy may be of clinical relevance for an improved risk assessment of the individual fetus during the critical transition from intrauterine life to the outside and for the development of potential prophylactic measures against severe ante- or intrapartum hypoxia. Responses of the tissue to reperfusion deserve intensive study, since they may provide a rational basis for preventive measures against reperfusion injury and related oxidative stress. Modification of the handling of placental tissue during postpartum ischemia, and adaptation of the artificial reperfusion, may lead to an improvement of the ex vivo perfusion technique.