Herd immunity drives the epidemic fadeout of avian cholera in Arctic-nesting seabirds.

Avian cholera, caused by the bacterium Pasteurella multocida, is a common and important infectious disease of wild birds in North America. Between 2005 and 2012, avian cholera caused annual mortality of widely varying magnitudes in Northern common eiders (Somateria mollissima borealis) breeding at the largest colony in the Canadian Arctic, Mitivik Island, Nunavut. Although herd immunity, in which a large proportion of the population acquires immunity to the disease, has been suggested to play a role in epidemic fadeout, immunological studies exploring this hypothesis have been missing. We investigated the role of three potential drivers of fadeout of avian cholera in eiders, including immunity, prevalence of infection, and colony size. Each potential driver was examined in relation to the annual real-time reproductive number (Rt) of P. multocida, previously calculated for eiders at Mitivik Island. Each year, colony size was estimated and eiders were closely monitored, and evaluated for infection and serological status. We demonstrate that acquired immunity approximated using antibody titers to P. multocida in both sexes was likely a key driver for the epidemic fadeout. This study exemplifies the importance of herd immunity in influencing the dynamics and fadeout of epidemics in a wildlife population.

[Dorsal preservation septorhinoplasty]. / Die nasenrückenerhaltende "Dorsal-Preservation"-Septorhinoplastik.

BACKGROUND: Nasal dorsum deprojection is a very important tool in functional and aesthetic rhinoplasty. In classic techniques, resection of dorsal bone and cartilage renders dorsal reconstruction necessary. The concept of dorsal preservation rhinoplasty has been known for more than a century but has experienced a renaissance in recent years, with many critical technical modifications. MATERIALS AND METHODS: We present the latest technique of piezo-assisted dorsal preservation rhinoplasty with subdorsal triangular resection and subdorsal Cottle modification based on clinical experience of 205 cases. Furthermore, the advantages and disadvantages of this technique are discussed and several other current variations are presented. RESULTS AND DISCUSSION: Piezo-assisted osteotomy enables a very precise fracture line and sparing of periosteum, with bone sculpting possible even after mobilization. Subdorsal septal height reduction always precedes completion of the osteotomy and nasal bone mobilization, to ensure patient safety with regard to skull base injury. Using the presented technical modifications, the risk of step deformities in the radix is minimized. In selected patients, dorsal preservation septorhinoplasty enables the surgeon to perform very conservative and precise deprojection of the nose with excellent outcomes, although the spectrum of possible complications is shifted in comparison to classic techniques. CONCLUSION: The preliminary experience of 205 cases with a revision rate of less than 10% is promising. A final evaluation of the technique will only be possible after further studies and evaluation of long-term results.

Matrix-assisted laser desorption/ionization imaging mass spectrometry for the spatial location of feline oviductal proteins.

With the purpose of identifying factors involved in early stages of embryo development in the domestic cat, matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS) was used for the first time to describe the spatial localization of proteins in the oviducts of queens. Oviducts were obtained from two 2 and 4 years old cross-bred queens, divided into three segments, snap-frozen in liquid nitrogen and then stored at -80°C until use. Next, they were sectioned in a cryostat, fixed on ITO (indium tin oxide) conductive glass slides for MALDI-IMS and serial sections were collected on microscope slides for histology. As confirmed by histology, MALDI-IMS was able to show contrasting protein distributions in the oviductal infundibulum, ampulla and isthmus. Mass spectra were characterized by abundant ions of m/z 1,259, 4,939, 4,960 and 10,626, which have been tentatively attributed to keratin, thymosin ß10, thymosin ß4 and S100, respectively. Keratin and thymosins are involved in the biological response to tissue damage. S100 proteins are calcium-modulated proteins implicated in a variety of cellular activities, including cell differentiation and regulation of cell motility. These results suggest that protein composition differs between segments of the cat oviduct, which corresponds to morphological changes within these sections. Further functional studies could elucidate the effects of these proteins on feline reproductive physiology.

Changes in acetylation of lysine 5 on histone H4 in canine oocytes following in vitro maturation.

Post-translational modifications of histones, such as acetylation, are involved in regulating chromatin remodelling and gene expression. Proper in vitro maturation (IVM) of canine oocytes, for many reasons, is up to now inefficient. This study aimed to evaluate the post-translational histone H4 acetylation at lysine 5 (H4K5) in immature and post-IVM canine oocytes. Oocyte nuclear stage was assessed using Hoechst 33342 staining. Acetylation patterns were determined by indirect immunofluorescence staining of immature and post-IVM oocytes, using an antibody against the acetylated lysine 5 residue on histone 4 (H4K5ac). The experiment was repeated four times, with a total of 7-17 oocytes evaluated per stage. Immunofluorescence signal was quantified using the NIHimagej software. Data were expressed as a percentage of the average fluorescence intensity of the specific antibody over the intensity of DNA, as determined by Hoescht staining. H4K5ac displayed a significantly higher acetylated pattern in immature oocytes (0.97 ± 0.08) when compared to post-IVM oocytes at different nuclear stages. There was a decrease in the fluorescence level of the matured oocytes with the progression of meiosis (GVBD: 0.47 ± 0.06 and MI/MII: 0.35 ± 0.04). Similarly to other domestic species, we hypothesized that post-translational modification of histone acetylation takes place during meiosis of in vitro matured canine oocytes. However, it remains to be investigated whether these changes occur during in vivo maturation.

In vitro maturation of oocytes from Santa Ines ewes subjected to consecutive sessions of follicular aspiration by laparoscopy.

The success of embryo production in vitro depends upon the use of an efficient oocyte retrieval technique, and the best results have been obtained by laparoscopic aspiration. The aim of this study was to evaluate the effect of consecutive sessions of follicular aspiration on the quantity, quality and in vitro maturation competence of oocytes obtained from ewes subjected to hormonal stimulation. Six Santa Ines ewes underwent nine sessions of follicular aspiration by laparoscopy with a 7-day interval between sessions, totalling 56 aspirations. After 24 h of culture, oocytes were stained and classified according to the stage of nuclear and cytoplasmic maturation. Oocyte retrieval rate was 61.4 ± 2%, resulting in a total of 249 oocytes. No significant variation was observed between sessions (p > 0.05). The average number of oocytes retrieved from each ewe was 6.4 ± 2 per session and 42 ± 4 in total. No significant difference was observed between the frequencies of the different stages of nuclear maturation: 32.72% mature, 40.74% immature and 26.54% degenerated/indeterminate oocytes; however, a significant difference was observed between the frequencies of the different stages of cytoplasmic maturation: 10.7% mature, 73.25% immature and 16.05% degenerated/indeterminate oocytes. No significant difference was observed in nuclear or cytoplasmic maturation between the weeks of procedure. We conclude that after nine consecutive sessions of follicular aspiration, the quantity and quality of retrieved oocytes remained unchanged as well as the levels of nuclear and cytoplasmic maturation obtained, demonstrating the viability of this technique for repetitive follicular aspirations on the same donor.

In vitro survival of follicles collected from domestic cats' ovaries at different stages of oestrous cycle and cultured with IGF-1.

Optimal conditions for in vitro culture of feline ovarian follicles have not yet been defined. Follicular development is regulated by intraovarian growth factors, as insulin-like growth factor (IGF-1), and during the different stages of the oestrous cycle, follicles are exposed to specific hormonal environments. The aim of this study was to investigate the effect of IGF-1 on in vitro growth and granulosa cell (GC) viability of preantral follicles collected from domestic cats at follicular and luteal phases of the oestrous cycle. Oestrus and ovulation were induced in 12 cats. A total of 39 and 32 follicles collected at the follicular and luteal phases, respectively, were individually cultured in vitro for 6 days in minimum essential medium media supplemented with or without IGF-1 (100 ng/ml). Follicles collected during the follicular phase and cultured without IGF-1 displayed a significant increase in size and higher GC viability (46.5 ± 22.1 µm, 66.7%, respectively) than that of follicles collected at the luteal phase and cultured without IGF-1 (26.7 ± 14.4 µm, 50%, respectively; p < 0.05). In contrast, when IGF-1 was added to the culture medium, no differences were observed in size or GC viability between follicles collected at the two phases of the cycle. Nonetheless, follicles collected at the luteal phase and cultured with IGF-1 had a significant increase in their diameter and GC viability (31.9 ± 15.9 µm, 63.6%, respectively) than that cultured without IGF-1 (26.7 ± 14.4 µm, 50%, respectively; p < 0.05). These data suggest that in vitro growth and GC survival of feline preantral follicles are affected by the oestrous cycle phase, and the IGF-1 exerts a positive effect on follicles collected at the luteal phase.

Costs of reproduction in a long-lived bird: large clutch size is associated with low survival in the presence of a highly virulent disease.

Fitness costs of reproduction are expected to be more pronounced when the environmental conditions deteriorate. We took advantage of a natural experiment to investigate the costs of reproduction among common eiders (Somateria mollissima) nesting at a site in the Arctic, where an avian cholera epizootic appeared at different magnitudes. We tested the predictions that larger reproductive effort (clutch size) is associated with lower survival or breeding probability the following year, and that this relationship was more pronounced under heightened exposure to the disease. Our results indicate that large clutch sizes were associated with lower survival of female eider ducks, but only when there was heightened exposure to avian cholera, as indexed by eider mortality on site. No cost was observed when cholera was absent or when lesser exposure was evident. This supports the hypothesis that fitness costs of high reproductive effort are higher under unfavourable conditions such as a disease epizootic, and further indicates that being a conservative breeder can increase survival probability, given the presence of a highly virulent disease.

[Surgical techniques in hepatic resections: Ultrasonic aspirator versus Jet-Cutter. A prospective randomized clinical trial]. / Wasserstrahldissektion bei Leberresektion: Ultraschallaspirator versus Jet-Cutter - Eine prospektiv randomisierte Studie -

AIM OF THE STUDY: For all resection-techniques of liver tissue intra- and post-operative blood-loss remains an important problem. Two novel resection-techniques the ultrasound-aspirator (CUSA) and the water-jet dissector (Jet-Cutter) appear to offer significant advantages regarding this problem. Aim of the present prospective clinical study was the comparison of these dissection techniques. MATERIAL AND METHODS: Prospective randomized study with the end points blood-loss, length of surgery, tissue trauma and long-term survival. FINDINGS: Significant differences between both procedures with Jet-Cutter (n = 31) versus ultrasonic surgical aspirator CUSA (n = 30) were observed regarding length of resection and complete liver ischemia time (Pringle-time). Here significant advantages of the jet-cutter-technique were observed with 28 +/- 11 minutes length of resection versus 46 +/- 19 minutes and 29 +/- 12 minutes Pringle-time versus 39 +/- 16 minutes. Furthermore, significant fewer blood transfusions were required following jet-cutter-resection with a mean of 1.5 blood units vs. 2.5 blood units using the CUSA. No differences were observed regarding postoperative long-term survival. CONCLUSIONS: The jet-cutter-technique is a fast and safe surgical procedure for liver resections and offers an attractive therapeutic alternative for various indications in liver surgery.

Impact of virtual reality imaging on hepatic liver tumor resection: calculation of risk.

The risk involved in partial liver resections depends mainly on tumor localization, invasion of central vascular structures, and parenchymal function. The imaging techniques available today (computed tomography, magnetic resonance imaging) allow us to detect precisely the extent of tumor invasion and their relationship to central vessels. The various three-dimensional reconstruction techniques are helpful with regard to a virtual planning of liver resections. The calculation of remaining liver volumes subsequent to partial hepatectomies are considered to be an essential predictive parameter in terms for the development of postoperative liver failure. In a retrospective and a later consecutive, prospective clinical study we analyzed the postoperative risk in a series of 570 patients. In an univariate analysis 13 of 31 parameters showed significant values. In multivariate analysis only three parameters (partial hepatic resection rate, PHRR), gamma-glutamyltranspeptidase, and prothrombin activity) were independent parameters for predicting liver failure, generating the most significant values for the PHRR. In our experience the most comfortable and precise technique for evaluating PHRR is the b-spline technique.

Laparoscopic liver resection compared with conventional partial hepatectomy--a prospective analysis.

BACKGROUND/AIMS: Tumor size and location are the major influences on the practicality of a laparoscopic operation. Visual control of the operating field is important for isolation and ligation of blood vessels and bile ducts after selective liver dissection by suitable techniques such as the water-jet dissector. METHODOLOGY: We carried out laparoscopic liver resections with the Jet-Cutter in 17 patients. The results were compared to a control group of 17 closely matched patients undergoing conventional hepatic resection during the period of the study. In 1 patient, conversion of laparoscopic to an open operation was required. RESULTS: Early in our learning curve, the duration of operation and time for resection were significantly longer in the laparoscopic group. Following laparoscopic operation, patients were discharged from the hospital after a mean of 7.8+/-8.2 days; patients having undergone conventional operation were discharged after a mean of 11.6+/-12.8 days. CONCLUSIONS: Laparoscopic liver resection is technically feasible, but, at present, careful patient selection is required.

Preoperative risk assessment of hepatic resection for malignant disease.

Clinical, laboratory, functional, and volumetric data of 340 consecutive patients undergoing hepatic resection for malignant disease between November 1990 and June 1995 were analyzed. The operative mortality was 3.3% (8/244 patients). Among 178 patients with liver metastases and 66 with primary hepatobiliary tumors the hospital mortality was 4.1% (10/244 patients) and morbidity 22.0% (54/244 patients). Survival after hepatectomy was strongly influenced by the extent of resection quantified by the parenchymal hepatic resection rate. The prediction of fatal postoperative complications can be improved for patients with hepatic metastases by calculating the liver resection index (sensitivity 75%, specificity 83%).

Jet-cutting supported by high frequency current: new technique for hepatic surgery.

To reduce blood loss incurred during liver resection, techniques that separate vessels from liver parenchyma, such as the CUSA or the jet-cutter, are in clinical use. By conducting high frequency current through the jet beam using hypertonic NaCl cutting solution, we developed a new method enabling simultaneous coagulation during selective cutting. In this study we examined the effects of this method on liver resection in a rabbit model. With the three techniques-jet-cutting, CUSA, and high frequency-supported jet-cutting (HF-jet)-we performed liver resection of the ventral lobe in six animals per group. We compared velocity of resection, blood loss, tissue trauma, selectivity (number of isolated vessels per area), electrolytes, and vital signs. Histopathology was carried out with the resectate and after 7 days with the remaining liver. Velocity of resection procedure and selectivity were significantly reduced in the HF-jet group. Histopathology showed coagulated vessels and a deeper zone of necrosis. Accordingly, the liver enzymes transiently showed distinctly higher values in the HF-jet group. Electrolyte disturbances or differences of vital signs could not be detected. Transferring our results to patient care we expect that with major resections the hilus clamping time, blood loss, and number of blood transfusions can be reduced. In our opinion the additional application of high frequency through the jet beam is a helpful improvement of the jet-cutter.

[Liver resection with the water jet: conventional and laparoscopic surgery]. / Leberresektion mit dem Wasser-Jet: konventionell und laparoskopisch.

In a prospective study 60 patients underwent liver resection. Two different resection techniques, ultrasonic aspirator (CUSA, n = 30) and Jet-Cutter (n = 30), were compared, Speed of resection, blood loss, transfusion rate, liver hilus clamping time and tissue damage were evaluated on the basis of the area of transsected liver. Liver resection with the Jet-Cutter was significantly faster with a resection time of 0.35 min/cm2 in comparison to the CUSA (0.77 min/cm2, p < 0.001) and associated with less blood loss of 18.4 ml/cm2 (p < 0.05) than the CUSA technique (34.4 ml/cm2). Tissue damage in respect to levels of transaminases SGOT and SGPT was comparable with both techniques. The Jet-Cutter is a promising new instrument in liver surgery, and challenged by these results we used the Jet-Cutter in 7 patients performing laparoscopic liver resections.

A comparison of different techniques for liver resection: blunt dissection, ultrasonic aspirator and jet-cutter.

In a prospective study 116 patients underwent liver resection. Three different resection techniques, blunt dissection (n = 61), ultrasonic aspirator (CUSA) (n = 27) and jet-cutter (n = 28) were compared. Speed of resection, blood loss, transfusion rate, liver hilus clamping time and tissue damage were evaluated on the basis of area of transected liver surface. Liver resection with the jet-cutter was significantly faster with a resection time of 0.33 min/cm2 in comparison to blunt dissection (0.57 min/cm2) and CUSA (0.50 min/cm2) (P < 0.01) and associated with lower blood loss of 17.7 ml/cm2 (P < 0.01) than the other techniques (blunt dissection 32.5 ml/cm2, CUSA 24.3 ml/cm2). Tissue damage with respect to transaminases SGOT and SGPT was comparable to the other techniques. The jet-cutter is a promising new instrument in liver surgery.