Computer Aided Surgery for Percutaneous Nephrolithotomy: Clinical Requirement Analysis and System Design

Percutaneous nephrolithotomy (PCNL) for the treatment of renal stones and other related renal diseases has proved its efficacy and has stood the test of time compared with open surgical methods and extracorporal shock wave lithotripsy. However, access to the collecting system of the kidney is not easy because the available intra-operative image modalities only provide a two dimensional view of the surgical scenario. With this lack of visual information, several punctures are often necessary which, increases the risk of renal bleeding, splanchnic, vascular or pulmonary injury, or damage to the collecting system which sometimes makes the continuation of the procedure impossible. In order to address this problem, this paper proposes a workflow for introduction of a stereotactic needle guidance system for PCNL procedures. An analysis of the imposed clinical requirements, and a instrument guidance approach to provide the physician with a more intuitive planning and visual guidance to access the collecting system of the kidney are presented.

Differential requirement for ROCK in dendritic cell migration within lymphatic capillaries in steady-state and inflammation

Dendritic cell (DC) migration via lymphatic vessels to draining lymph nodes (dLNs) is crucial for the initiation of adaptive immunity. We imaged this process by intravital microscopy (IVM) in the ear skin of transgenic mice bearing red-fluorescent vasculature and yellow-fluorescent DCs. DCs within lymphatic capillaries were rarely transported by flow, but actively migrated within lymphatics and were significantly faster than in the interstitium. Pharmacologic blockade of the Rho-associated protein kinase (ROCK), which mediates nuclear contraction and de-adhesion from integrin ligands, significantly reduced DC migration from skin to dLNs in steady-state. IVM revealed that ROCK blockade strongly reduced the velocity of interstitial DC migration, but only marginally affected intralymphatic DC migration. By contrast, during tissue inflammation, ROCK blockade profoundly decreased both interstitial and intralymphatic DC migration. Inhibition of intralymphatic migration was paralleled by a strong up-regulation of ICAM-1 in lymphatic endothelium, suggesting that during inflammation ROCK mediates de-adhesion of DC-expressed integrins from lymphatic-expressed ICAM-1. Flow chamber assays confirmed an involvement of lymphatic-expressed ICAM-1 and DC-expressed ROCK in DC crawling on lymphatic endothelium. Overall, our findings further define the role of ROCK in DC migration to dLNs and reveal a differential requirement for ROCK in intralymphatic DC crawling during steady-state and inflammation.

Autophagy in Trypanosoma brucei: amino acid requirement and regulation during different growth phases.

Autophagy in the protozoan parasite, Trypanosoma brucei, may be involved in differentiation between different life cycle forms and during growth in culture. We have generated multiple parasite cell lines stably expressing green fluorescent protein- or hemagglutinin-tagged forms of the autophagy marker proteins, TbAtg8.1 and TbAtg8.2, in T. brucei procyclic forms to establish a trypanosome system for quick and reliable determination of autophagy under different culture conditions using flow cytometry. We found that starvation-induced autophagy in T. brucei can be inhibited by addition of a single amino acid, histidine, to the incubation buffer. In addition, we show that autophagy is induced when parasites enter stationary growth phase in culture and that their capacity to undergo starvation-induced autophagy decreases with increasing cell density.

A randomised controlled trial: can acupuncture reduce drug requirement during analgosedation with propofol and alfentanil for colonoscopy? A study protocol.

BACKGROUND The number of colonoscopies tremendously increased in recent years and will further rise in the near future. Because of patients' growing expectation on comfort during medical procedures, it is not surprising that the demand for sedation also expands. Propofol in combination with alfentanil is known to provide excellent analgosedation, however, its use is associated with respiratory and cardiovascular depression. Acupuncture could be a technique to reduce drug requirement while providing the same level of sedation and analgesia. METHODS/DESIGN The study will be performed as a single centre, randomised, placebo controlled trial. 153 patients scheduled for propofol/alfentanil sedation during colonoscopy will be randomly assigned to receive electroacupuncture (P6, ST36, LI4), sham acupuncture, or placebo acupuncture. Following endoscopy patients and gastroenterologists have to fill in questionnaires about their sedation experiences. Additionally, patients have to accomplish the Trieger test before and after the procedure. Patient monitoring includes time adapted HR, SpO2, ECG, NIBP, exCO2, OAA/S, and the Aldrete score. The primary outcome parameter is the dosage of propofol necessary for an adequate level of sedation to tolerate the procedure (OAA/S < 4). Effectiveness of sedation, classified by satisfaction levels measured by questionnaires is the secondary outcome parameter. DISCUSSION Moderate to deep sedation using propofol is increasingly applied during colonoscopies with a high satisfaction level among patients despite well-known hemodynamic and respiratory side effects of this hypnotic agent. Acupuncture is known to attenuate gastrointestinal discomfort and pain. We hypothesize that the combination of conventional sedation techniques with acupuncture may result in equally satisfied patients with a lower risk of respiratory and hemodynamic events during colonoscopies. TRIAL REGISTRATION This trial is registered in the Nederland's Trial Register NTR 4325 . The first patient was randomized on 13 February 2014.

Space requirement of a prefabricated bar on two interforaminal implants: a prospective clinical study

OBJECTIVES This clinical study measured the dimensional changes of existing lower complete dentures due to the integration of a prefabricated implant bar. Additionally, the impact of this dimensional change on patient satisfaction and oral function was analyzed. METHODS Twenty edentulous patients (10 men/10 women; aged 65.9 ± 11.8 years) received two interforaminal implants. Subsequent to surgery, a chair side adapted, prefabricated bar (SFI Bar(®), C+M, Biel, Switzerland) was inserted, and the matrix was polymerized into the existing lower denture. The change of the denture's lingual dimension was recorded by means of a bicolored, silicone denture duplicate that was sectioned in the oro-vestibular direction in the regions of the symphysis (S) and the implants (I-left, I-right). On the sections, the dimensional increase was measured using a light microscope. Six months after bar insertion, patients answered a standardized questionnaire. RESULTS All dentures exhibited increased lingual volume, more extensively at S than at I (P = 0.001). At S, the median diagonal size of the denture was doubled (+4.33 mm), and at I, the median increase was 50% (I-left/-right = +2.66/+2.62 mm). The original denture size influenced the volume increase (P = 0.024): smaller dentures led to a larger increase. The amount of denture increase did not have negative impact on either self-perceived oral function or patient satisfaction. Approximately, 95% of the patients were satisfied with the treatment results. CONCLUSIONS The lingual size of a lower denture was enlarged by the integration of a prefabricated bar without any negative side effects. Thus, this attachment system is suitable to convert an existing full denture into an implant-supported overdenture.

Light-independent degradation of stromal proteins in intact chloroplasts isolated from Pisum sativum L. leaves: requirement for divalent cations

Intact chloroplasts were isolated from mature pea (Pisum sativum L.) leaves in order to study the degradation of several stromal proteins in organello. Changes in the abundances of ribulose-1,5-bisphosphate carboxylase/oxygenase (EC 4.1.1.39), phosphoribulokinase (EC 2.7.1.19), glutamine synthetase (EC 6.3.1.2) and ferredoxin-dependent glutamine:α-ketoglutarate aminotransferase (glutamate synthase; EC 1.4.7.1) were detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by Coomassie-staining of the gels or immunoblotting using specific antibodies for the different enzymes. Degradation of several stromal proteins was strongly stimulated when intact chloroplasts were incubated in the light in the presence of dithiothreitol. Since free radicals may artificially accumulate in the chloroplast under such conditions and interfere with the stability of stromal proteins, the general relevance of these processes remains questionable. In the absence of light, proteolysis proceeded slowly in isolated chloroplasts and was not stimulated by dithiothreitol. Inhibition by ethylenediaminetetraacetic acid (EDTA), 1,10-phenanthroline or excess zinc ions as well as the requirement for divalent cations suggested that a zinc-containing metalloprotease participated in this process. Furthermore, light-independent degradation of ribulose-1,5-bisphosphate carboxylase/oxygenase and phosphoribulokinase was enhanced in chloroplasts isolated from leaves in which senescence was accelerated by nitrogen starvation. Our results indicate that light-independent stromal protein degradation in intact chloroplasts may be analogous to proteolysis that occurs in intact leaves during senescence.

The Differential Requirement of Albumin and Sodium Citrate on the Development of In Vitro Produced Bovine Embryos

In vitro culture for bovine embryos is largely not optimal. Our study was to determine the components necessary for early embryo development. In experiment 1, IVF embryos were cultured for two days in CR1aa medium containing sodium citrate and BSA from two sources (Sigma vs. ICPbio), subsequently for additional five days with cumulus monolayer in 10% FBS CR1aa. We found that supplementation with both Sigma-BSA and sodium citrate significantly increased total blastocyst (BL) development compared with the ICPbio-BSA groups (37% vs. 19-21%), and enhanced the total number of high quality (C1 BL, IETS standard) blastocysts (26% vs. 11-17%) (P < 0.05). In experiment 2 with serum free and/or somatic free culture, we found that CR1aa culture can support a comparable embryo development with a supplement of Sigma BSA. The addition of sodium citrate did not increase blastocyst development in either the Sigma-BSA or the ICPbio-BSA groups. An inferior blastocyst development occurring in ICPbio-BSA culture (1-3%) could be rescued by culture in CRlaa supplemented with 10% FBS (29%), more importantly, by culture in CR1aa with a replacement of Sigma BSA (24%) (P <0.05). C1 blastocysts rescued by FBS and Sigma BSA in ICPbio-BSA culture possessed indistinguishable morphology to embryos developed in a Sigma-BSA, FBS and somatic co-culture system, showing similar cell number/blastocyst (129-180, P > 0.05). Our study found a beneficial effect of sodium citrate and BSA on the in vitro development of bovine IVF embryos during co-culture. We also determined that differential embryotrophic factor(s) contained in BSA and serum, probably not sodium citrate, is necessary for promoting competent morula and blastocyst development in cattle.

Differential Cytoplast Requirement for Embryonic and Somatic Cell Nuclear Transfer in Cattle

Effective activation of a recipient oocyte and its compatibility with the nuclear donor are critical to the successful nuclear reprogramming during nuclear transfer. We designed a series of experiments using various activation methods to determine the optimum activation efficiency of bovine oocytes. We then performed nuclear transfer (NT) of embryonic and somatic cells into cytoplasts presumably at G1/S phase (with prior activation) or at metaphase II (MII, without prior activation). Oocytes at 24 hr of maturation in vitro were activated with various combinations of calcium ionophore A23187 (A187) (5 microM, 5 min), electric pulse (EP), ethanol (7%, 7 min), cycloheximide (CHX) (10 micro g/ml, 6 hr), and then cultured in cytochalasin D (CD) for a total of 18 hr. Through a series of experiments (Exp. 1-4), an improved activation protocol (A187/EP/CHX/CD) was identified and used for comparison of NT efficiency of embryonic versus somatic donor cells (Exp. 5). When embryonic cells from morula and blastocysts (BL) were used as nuclear donors, a significantly higher rate of blastocyst development from cloned embryos was obtained with G1/S phase cytoplasts than with MII-phase cytoplasts (36 vs. 11%, P < 0.05). In contrast, when skin fibroblasts were used as donor cells, the use of an MII cytoplast (vs. G1/S phase) was imperative for blastocyst development (30 vs. 6%, P < 0.05). Differential staining showed that parthenogenetic, embryonic, and somatic cloned BL contained 26, 29, and 33% presumptive inner cell mass (ICM) cells, respectively, which is similar to that of frozen-thawed in vivo embryos at a comparable developmental stage (23%). These data indicate that embryonic and somatic nuclei require different recipient cytoplast environment for remodeling/ reprogramming, and this is likely due to the different cell cycle stage and profiles of molecular differentiation of the transferred donor nuclei.

Requirement of GCN5 histone acetyltransferase in mouse neural tube closure and skeletal patterning

Histone acetylation plays an essential role in many DNA-related processes such as transcriptional regulation via modulation of chromatin structure. Many histone acetytransferases have been discovered and studied in the past few years, but the roles of different histone acetyltransferases (HAT) during mammalian development are not well defined at present. Gcn5 histone acetyltransferase is highly expressed until E16.5 during development. Previous studies in our lab using a constitutive null allele demonstrated that Gcn5 knock out mice are embryonic lethal, precluding the study of Gcn5 functions at later developmental stages. The creation of a conditional Gcn5 null allele, Gcn5flox allele, bypasses the early lethality. Mice homozygous for this allele are viable and appear healthy. In contrast, mice homozygous for a Gcn5 Δex3-18 allele created by Cre-loxP mediated deletion display a phenotype identical to our original Gcn5 null mice. Strikingly, a Gcn5flox(neo) allele, which contain a neomycin cassette in the second intron of Gcn5 is only partially functional and gives rise to a hypomorphic phenotype. Initiation of cranial neural tube closure at forebrain/midbrain boundary fails, resulting in an exencephaly in some Gcn5flox(neo)/flox(neo) embryos. These defects were found at an even greater penetrance in Gcn5flox(neo)/Δ embryos and become completely penetrant in the 129Sv genetic background, suggesting that Gcn5 controls mouse neural tube closure in a dose dependent manner. Furthermore, both Gcn5flox(neo)/flox(neo) and Gcn5 flox(neo)/Δ embryos exhibit anterior homeotic transformations in lower thoracic and lumbar vertebrae. These defects are accompanied by decreased expression levels and a shift in anterior expression boundary of Hoxc8 and Hoxc9. This study provides the first evidence that Gcn5 regulates Hox gene expression and is required for normal axial skeletal patterning in mice. ^

Vital function for PRELI and essential requirement for its LEA motif

Proteins containing the late embryogenesis abundant (LEA) motif comprise an evolutionarily conserved family, long postulated to protect plant embryos from stress and death. However, the significance of LEA-containing proteins and the mechanisms behind their function remain undetermined. Here we show that PRELI, a mammalian protein that possesses tandem repeats of the LEA motif, can protect cells against staurosporine, TNF-α or UV irradiation-induced apoptosis. We found that key to PRELI-dependent mechanisms that promote cell resistance to death are the stabilization of the respiratory chain, upholding of mitochondrial membrane potential and retention of apoptogenic molecules. By in vitro and in vivo studies, we also show that the expression of mutant PRELI/LEA- proteins lacking the LEA motif, results in the complete loss of PRELI's anti-apoptotic functions. Collectively, our data uncover a new molecular player in the control of apoptosis and support the hypothesis that LEA-containing proteins are evolutionarily conserved cell protectors against stress and death. ^

Requirement of the Jak2 tyrosine kinase in Bcr -Abl oncogenic transformation

Philadelphia chromosome (Ph)-positive chronic myeloid leukemia is caused by a clonal myeloproliferative expansion of malignant primitive hematopoietic progenitor cells. The Ph results from the reciprocal translocation of the ends of chromosome 9 and 22, which generate Bcr-Abl fusion proteins. The Bcr-Abl proteins possess a constitutively activated Abl tyrosine kinase, which is the driving force responsible for causing leukemia. The activated Bcr-Abl tyrosine kinase stimulates multiple signal transduction pathway affecting growth, differentiation and survival of cells. It is known that the Bcr-Abl tyrosine kinase activates several signaling proteins including Stat5, which is a member of the Jak/Stat pathway that is activated by cytokines that control the growth and differentiation of normal hematopoietic cells. Our laboratory was the first one to report that Jak2 tyrosine kinase is activated in a human Bcr-Abl positive hematopoietic cell line. In this thesis, we further investigated the activation of Jak2 by Bcr-Abl. We found that Jak2 is activated not only in cultured Bcr-abl positive cell lines but also in blood cells from CML blast crisis patients. We also demonstrated that SH2 domain of Bcr-Abl is required for efficient activation Jak2. We further showed that Jak2 binds to the C-terminal domain of Bcr-Abl; tyrosine residue 1007, which is critical for Jak2 activation, is phosphorylated by Bcr-Abl. We searched downstream targets of Jak2 in Bcr-Abl positive cells. We treated Bcr-Abl positive cells with a Jak2 kinase inhibitor AG490 and found that c-Myc protein expression is inhibited by AG490. We further demonstrated that Jak2 inhibitor AG490 not only inhibit C-MYC transcription but also protect c-Myc protein from proteasome-dependent degradation. We also showed that AG490 did not affect Bcr-Abl kinase activity and Stat5 activation and its downstream target Bcl-xL expression. AG490 also induced apoptosis of Bcr-Abl positive cells, similar to Bcr-Abl kinase inhibitor STI571 (also termed Gliveec, a very effective drug for CML), but unlike STI571 the apoptosis effects induced by AG490 can not be rescued by IL-3 containing WEHI conditioned medium. We further established several Bcr-Abl positive clones that express a kinase-inactive Jak2 and found that these clones had reduced tumor formation in nude mice assays. Taken together, these results establish that Jak2 is activated in Bcr-Abl positive CML cells and it is required for c-Myc induction and the oncogenic effects of Bcr-Abl. Furthermore, Jak2 and Stat5 are two independent targets of Bcr-Abl. ^