Protection against FIV challenge infection by genetic vaccination using minimalistic DNA constructs for FIV env gene and feline IL-12 expression.

OBJECTIVE: To evaluate the efficacy of a genetic vaccination protocol based on minimalistic, immunogenic defined gene expression (MIDGE) vectors coding for domains of the feline immunodeficiency virus (FIV) env gene and feline IL-12. METHODS: Three groups of four cats each were immunized three times within 6 weeks by the ballistic transfer of gold particles coated with MIDGE vectors. Group 1 received non-coated gold beads, groups 2 and 3 MIDGE vectors expressing FIV surface plus part of the transmembrane protein. In addition, group 3 received feline IL-12 DNA. All cats were challenged by intraperitoneal injection of 25 TCID50 of infectious FIV Z2. The following criteria were monitored: clinical signs, antibodies to transmembrane protein, antibodies to whole FIV, haematological parameters and kinetics of CD4 and CD8 cells, FIV proviral load (determined by quantitative polymerase chain reaction; PCR) and cytotoxic T lymphocyte (CTL) activity (in selected cats). RESULTS: None of the cats developed a detectable antibody response during immunizations. Four weeks after challenge exposure, all cats in group 1 (control) and group 2 (FIV surface-transmembrane protein) had seroconverted and showed a high proviral load until week 19 (end of experiment). In contrast, only one of four cats in group 3 (surface-transmembrane protein and IL-12) showed antibodies; it was provirus positive at reduced virus load. Short-lived CTL activity was found in two cats in group 3. CONCLUSION: Genetic vaccination using a MIDGE-based construct for the expression of the surface-transmembrane protein domain of FIV env and feline IL-12 DNA led to protection against homologous virus challenge in three out of four vaccinated cats.

Anesthesia alters pulmonary vasoregulation by angiotensin II and captopril.

We investigated the effects of an intravenous (pentobarbital sodium) and inhalational (halothane) general anesthetic on the pulmonary vascular responses to angiotensin II and angiotensin-converting enzyme inhibition (CEI). Multipoint pulmonary vascular pressure-flow (P/Q) plots were generated in conscious pentobarbital- (30 mg/kg iv) and halothane-anesthetized (approximately 1.2% end-tidal) dogs in the intact (no drug) condition, during angiotensin II administration (60 ng.kg-1.min-1 iv), and during CEI (captopril 1 mg/kg plus 1 mg.kg-1.h-1 iv). In conscious dogs, angiotensin II increased (P less than 0.001) the pulmonary vascular pressure gradient [pulmonary arterial pressure--pulmonary arterial wedge pressure (PAP-PAWP)] over the empirically measured range of Q; i.e., angiotensin II caused pulmonary vasoconstriction. Pulmonary vasoconstriction (P less than 0.01) in response to angiotensin II was also observed during pentobarbital sodium anesthesia. In contrast, angiotensin II had no effect on the P/Q relationship during halothane anesthesia. In conscious dogs, CEI decreased (P less than 0.001) PAP-PAWP over the empirically measured range of Q; i.e., CEI caused pulmonary vasodilation. However, CEI caused pulmonary vasoconstriction (P less than 0.02) during pentobarbital sodium and had no effect on the P/Q relationship during halothane. Thus, compared with the conscious state, the pulmonary vasoconstrictor response to angiotensin II is unchanged or abolished, and the pulmonary vasodilator response to CEI is reversed to vasoconstriction or abolished during pentobarbital sodium and halothane anesthesia, respectively.

Acute and chronic pulmonary vasoconstriction after left lung autotransplantation in conscious dogs.

We investigated the acute and chronic effects of left lung autotransplantation (LLA) on the left pulmonary vascular pressure-flow (LP/Q) relationship in conscious dogs. Continuous LP/Q plots were generated in chronically instrumented conscious dogs 2 days, 2 wk, 1 mo, and 2 mo after LLA. Identically instrumented normal conscious dogs were studied at equal time points post-surgery. LLA had little or no effect on baseline systemic hemodynamics or blood gases. In contrast, compared with normal conscious dogs, striking active flow-independent pulmonary vasoconstriction was observed 2 days post-LLA. The slope of the LP/Q relationship was increased from a normal value of 0.275 +/- 0.021 to 0.699 +/- 0.137 mmHg.ml-1.min-1.kg-1 2 days post-LLA. Pulmonary vasoconstriction of similar magnitude was also observed on a chronic basis at 2 wk, 1 mo, and even 2 mo post-LLA. Pulmonary vasoconstriction post-LLA was not due to fixed resistance at the left pulmonary arterial or venous anastomotic sites. Finally, systemic arterial blood gases were unchanged when total pulmonary blood flow was directed to exclusively perfuse the transplanted left lung. Thus, LLA results in both acute and chronic pulmonary vasoconstriction in conscious dogs. LLA should serve as a useful stable experimental model to assess the specific effects of surgical transplantation on pulmonary vascular regulation.

Differential effects of general anesthesia on cGMP-mediated pulmonary vasodilation.

We investigated the effects of an intravenous (pentobarbital sodium) and an inhalational (halothane) general anesthetic on guanosine 3',5'-cyclic monophosphate- (cGMP) mediated pulmonary vasodilation compared with responses measured in the conscious state. Multipoint pulmonary vascular pressure-flow plots were generated in the same nine dogs in the fully conscious state, during pentobarbital sodium anesthesia (30 mg/kg iv), and during halothane anesthesia (approximately 1.2% end tidal). Continuous intravenous infusions of bradykinin (2 micrograms.kg-1.min-1) and sodium nitroprusside (5 micrograms.kg-1.min-1) were utilized to stimulate endothelium-dependent and -independent cGMP-mediated pulmonary vasodilation, respectively. In the conscious state, both bradykinin and nitroprusside decreased (P less than 0.01) the pulmonary vascular pressure gradient (pulmonary arterial pressure-pulmonary arterial wedge pressure) over the entire range of flows studied; i.e., bradykinin and nitroprusside caused active flow-independent pulmonary vasodilation. Pulmonary vasodilator responses to bradykinin (P less than 0.01) and nitroprusside (P less than 0.05) were also observed during pentobarbital anesthesia. In contrast, during halothane anesthesia, the pulmonary vasodilator responses to both bradykinin and nitroprusside were abolished. These results indicate that, compared with the conscious state, cGMP-mediated pulmonary vasodilation is preserved during pentobarbital anesthesia but is abolished during halothane anesthesia.

Hydrochlorothiazide-induced 131I excretion facilitated by salt and water.

Salt intake is restricted under clinical conditions for which thiazide diuretics are customarily used. Dietary iodide intake offsets any effect of thiazide on iodide loss. However, our correlation coefficients relating Na+ to Cl- to I- excretion indicate that as thiazide administration or sodium chloride intake increases renal Na+ and Cl- excretion, I- reabsorption by the nephron coordinately decreases. Increased sodium chloride and water intake by the dog doubled I-excretion rates. Hydrochlorothiazide increased the sodium chloride and water enhanced I-excretion rate as much as eight-fold. Without added NaCl, hydrochlorothiazide increased the excretion rate of 131I by three- to eightfold, acutely. Within five to seven days after 131I oral administration, hydrochlorothiazide (1 or 2 mg/kg twice daily) doubled the rate of 131I disappearance from plasma, reduced the fecal output of 131I, and increased its rate of renal excretion. When hydrochlorothiazide was administered, as much 131I was excreted in the first 24 hours as occurred in 48 hours when sodium chloride and water were given without hydrochlorothiazide. Thiazide administration in customary clinical dosage twice a day with substantial sodium chloride and water for the first two days after exposure to 131I, should therefore facilitate the safe excretion of 131I. This accelerated removal of 131I might be enhanced even more if thyroid uptake of 131I is blocked by administration of potassium iodide, as judged by the greater 131I recovery from thyroidectomized dogs.

31P-NMR evaluation of postischemia renal ATP and pH levels after ATP-MgCl2 treatment in rabbits.

Phosphorus-31 (31P) nuclear magnetic resonance (NMR) spectroscopy was used to measure adenosine triphosphate (ATP) concentration and pH in vivo in rabbits subjected to a 40-minute period of unilateral renal ischemia to determine the effect of infusing ATP-magnesium chloride (MgCl2, 100 mumol/kg) versus saline at the initiation of reperfusion. Data were compared initially by analysis of variance and then analyzed further using a general linear model with covariate adjustment. ATP-MgCl2-treated animals did not have higher ATP levels during recovery but did have significantly higher renal blood flow (p less than 0.05), a significantly decreased rate of recovery from acidosis (p less than 0.05), and significantly higher urinary output (p less than 0.01) than saline-treated animals during the recovery period. Therefore, treatment with ATP-MgCl2 improves postischemic functional parameters in this model of moderate injury without functioning as a direct source of ATP or its precursors. These data add support to the emerging concept that intracellular acidosis protects cells from reperfusion injury.

Nucleotide and predicted peptide sequence of feline interleukin-12 (IL-12).

Feline Interleukin-12 (IL-12) is a heterodimeric glycoprotein consisting of two disulfide linked subunits of about 40 kD (p40) and 35 kD (p35). It is a pleiotropic cytokine mediating biological activities on T- and NK-cells. One important function is the induction of a Th1 immune response. Here we report the cloning and sequencing of feline IL-12, the expression of the p40-protein in E. coli and production of monoclonal antibodies. At the nucleotide level, feline IL-12 shows between 87-90%, on the amino acid level between 82-87% identity to the bovine and human IL-12, respectively.

Viral infections in free-living populations of the European wildcat.

While the importance of viral infections is well studied in domestic cats, only limited information is available on their occurence and prevalence in the European wildcat (Felis silvestris silvestris). The aim of this study was to determine the prevalence of antibodies to feline coronavirus (FCoV), calicivirus (FCV), herpesvirus (FHV), parvovirus (FPV), immunodeficiency virus (FIV), leukemia virus (FeLV), and FeLV antigenemia in 51 European wildcat sera. Samples were collected between 1996 and 1997 from wildcat populations in France, Switzerland, and Germany. Antibodies to FCoV were detected in two cats (4%) and FCoV RNA was detected in feces of one of these two cats. Antibodies to FCV, FHV and FPV were found at relatively low frequencies of 16%, 4%, and 2%, respectively. Antibodies to FIV were not detected. Although antigen and antibodies to FeLV were detected in 49%, and 75%, respectively, no evidence of FeLV-associated pathology was found. From the low prevalence of FCoV, FCV, FHV and FPV infections and from the fact that the European wildcats live solitarily, it was concluded that these viral infections do not spread readily within a population. Therefore, it may be assumed that release into the wild of European wildcats bred in captivity would not bring about a high risk of introducing of these viral infections to the free-ranging wildcats. As an exception, wildcats should be tested for absence of FIV infection before release if they were at risk to acquire this infection from domestic cats.

Debonding forces applied to ceramic brackets simulating clinical conditions.

Debonding ceramic brackets is an area of concern to clinicians. Reports of enamel fractures and cracks have raised questions about the safety of the procedures used to remove these attachments. The purpose of this study was to compare the differences between the actual forces generated during bracket removal in the clinical setting and the shear forces applied during laboratory testing. Adhesive Remnant Index (ARI) scores are presented as a percentage of the total number of teeth tested and are compared between the two types of debonding methods. The ARI scores quantitatively express where the bond failure occurs during bracket removal. The results indicate that there is a significant difference between the mean bond strengths of the shear (107.8 kg/cm2) and the modified diametral compression (67.8 kg/cm2) forces. Debonding ceramic brackets with pliers requires the application of 30% less force to the enamel surface than debonding with the shear forces as tested in the laboratory. There were no significant differences in the ARI scores of the two groups--i.e. where the bond failures occurred.

[Detection of feline coronavirus using RT-PCR: basis for the study of the pathogenesis of feline infectious peritonitis (FIP)]. / Nachweis feliner Coronaviren mittels RT-PCR: Grundlage zum Studium der Pathogenese der Felinen Infektiösen Peritonitis (FIP).

The aim of this study was to further investigate the pathogenesis and epidemiology of feline coronavirus (FCoV)-infections and among others to determine the prognostic value of a positive result in the RT-PCR for FCoV in serum samples collected from cats with abdominal signs. Viral RNA was isolated from 100 microl of serum and subsequently amplified by a nested RT-PCR using primers binding to a highly conserved region of the 3'-end of the FCoV-genome. Sixty-three serum samples collected from 62 cats with abdominal signs were examined by RT-PCR and the clinical outcome was followed up. Four of these cats with a positive PCR-result are healthy more than 70 months after the collection of the blood sample. It can be concluded that viremia with FCoV does not necessarily lead to FIP and death. With respect to diagnosing FIP, a positive FCoV-RT-PCR is of low prognostic and diagnostic value. It can not be recommended to use this assay as sole indication to euthanize cats. Further studies will have to be carried out to demonstrate if the prognostic and diagnostic value of this PCR-assay in other samples such as peripheral blood mononuclear cells is more reliable. However, this method was found to be an important tool to further study the pathogenesis and epidemiology of FIP.

[Liberation into the wild of wild felines--danger of the release of virus infections]. / Auswilderung von Wildfeliden--Gefahr der Freisetzung von Virusinfektionen.

There are several felidae amongst the numerous endangered species. Means of aiding survival are the reintroduction to the wild of animals bred under the auspices of man and their relocation from densely populated to thinly populated areas. It is unlikely that the dangers of such reintroduction or relocation projects have been examined sufficiently in respect to the risks of virus infections confronting individuals kept in zoos or similar situations. This report presents three examples to illustrate that accidental virus infections may be expected to occur when relocating and reintroducing wild cats. The first example is the reintroduction of captive snow leopards. Zoo bred snow leopards may be infected with FIV, a virus infection that is highly unlikely to occur in the original himalayan highlands of Tibet and China. A second example is of several cases of FIP that occurred in European wild cats bred in groups in captivity. The third example mentioned is the relocation of lions from East Africa where all the commonly known feline viruses are wide-spread to the Etosha National Park. In the latter, virus infections such as FIV, FCV and FPV do not occur. The indiscriminate relocation and reintroduction of the wild cats mentioned here harbours a potential of undesirable consequences.

Ceramic brackets: something old, something new, a review.

This article reviews some of the characteristics of ceramic brackets that are of particular interest to the clinician. Various factors that may significantly influence bond strength and bracket removal are discussed. The information provided should enable the clinician to debond ceramic brackets safely applying available scientific information.

Working and Training Conditions of Gynecology Residents in North Rhine-Westfalia, Germany.

Introduction: In 2002, gynecology residents in North Rhine-Westfalia (NRW) were asked how satisfied they were with their working and training conditions. A new extended survey of gynecology residents aimed to evaluate whether changes to specialist training regulations had affected residents' levels of job satisfaction and to identify areas where training conditions still urgently required improvement. Material and Methods: A total of 1223 questionnaires with 52 questions were sent to the 159 gynecology clinics in NRW. Responses could be dichotomous, multi-level or quantitative. The results were analyzed with regard to age, gender, family status and type of clinic and were additionally compared with the results of a previous survey. Results: The percentage of women residents has increased to 84.6 %. A workload of more than 48 hours per week has resulted in decreased motivation and lower levels of satisfaction during training, although overall levels of satisfaction have clearly improved compared to the previous survey. Use of a logbook to create a more structured training program has not achieved the desired effect. Nevertheless, seven of eight gynecology residents would study medicine again, although 28 % of the budding gynecologists are considering working abroad or in private industry. Conclusion: Both training and overall satisfaction with working conditions must be improved to preserve the appeal of gynecology for young academics. This survey aims to identify key factors which are responsible for (dis)satisfaction with working conditions.

Comparisons of the effectiveness of pliers with narrow and wide blades in debonding ceramic brackets.

The removal of most ceramic brackets is accomplished by specially designed pliers that apply some form of tensile or shear force to the tooth surface. While the shear and tensile bond strengths for ceramic brackets in vitro have been reported, a simulation of the actual force application when using sharp-edged debonding pliers to debond a bracket has not. The purpose of this study is to determine the effectiveness and the force levels generated by the use of both the wide and the narrow blades in the debonding of ceramic brackets. The present findings indicate that the narrow blades effectively debonded ceramic brackets with a significantly lower mean debonding force (120 kg/cm2) than the wider blades (150 kg/cm2). The surface area of the blade in contact with the bracket-adhesive interface is less for the narrow blade (2.0 mm) than for the wide blade (3.2 mm). This relatively smaller contact area is sufficient to debond a bracket at a significantly lower debonding force.

A comparative study of the debonding strengths of different ceramic brackets, enamel conditioners, and adhesives.

The purpose of this study is to evaluate the use of a sharp-edged debonding instrument on four different ceramic brackets with three different bonding materials and two different enamel conditioning techniques. The effectiveness of the debonding instrument was determined by evaluating the following variables: the amount of force required to debond the bracket, the amount of residual adhesive remaining on the enamel surface, the frequency of bracket failure, and the prevalence of any visible enamel damage. The results indicated that the bracket type, the adhesive, as well as the enamel conditioner, all have an effect on bond strengths when using a sharp-bladed debonding instrument. The following conclusions were derived from the present findings: (1) The mean debonding strength values for the different bracket, adhesive, and enamel conditioner combinations ranged between a low of 40 kg/cm2 and a high of 194 kg/cm2. Most debonding values were between 60 and 115 kg/cm2. (2) A number of bracket, adhesive, and conditioner combinations are considered to have clinically adequate bonding strength and are relatively safe (Table IX). (3) The use of polyacrylic crystal growth enamel conditioner resulted in significantly less adhesive being left on the tooth as compared with the phosphoric acid enamel conditioner.

Intraoperative transesophageal echocardiography in a 1.4-kg infant with complex congenital heart disease.

The lower weight limit for infants undergoing intraoperative transesophageal echocardiography (TEE) with current commercially available probes has not been determined. A review of the literature reveals that infants as small as 1.6 kg have been studied successfully. This report describes the first intraoperative TEE reported in a 1.4-kg infant during truncus arteriosus/interrupted aortic arch repair. Successful pre- and postoperative images of the cardiac abnormality were obtained. Probe insertion was performed in this small patient after predilating the esophagus with a 14-F suction catheter.

Halothane constricts bovine pulmonary arteries by release of intracellular calcium.

In the canine lung, when compared with the conscious state, halothane causes vasoconstriction that is independent of blood flow. However, traditionally inhalational anesthetics have been shown to attenuate hypoxic pulmonary vasoconstriction and have therefore been considered pulmonary vasodilators. We have shown, in isolated bovine pulmonary artery, that halothane produces a transient contractile response. A variety of smooth muscle cellular mechanisms could be responsible for the vasoconstriction produced by halothane. The purpose of this study was to test the hypothesis that the halothane-induced contraction was caused by the release of sarcoplasmic reticular Ca++. Isometric tension was measured in isolated rings of bovine pulmonary artery with intact endothelium. Three protocols were followed. Rings were exposed to cyclopiazonic acid or ryanodine (modulators of sarcoplasmic reticular Ca++) (protocol 1), caffeine (protocol 2) verapamil or nicardipine (protocol 3). Halothane-induced contraction was measured before, during and after exposure to drug. In nominally Ca(++)-free buffer cyclopiazonic acid and ryanodine attenuated the halothane-induced contraction. Similar responses were seen with cyclopiazonic acid and ryanodine treatment when caffeine was substituted for halothane. The calcium channel blockers nicardipine and verapamil did not significantly alter the halothane-induced contraction. Our data in bovine pulmonary artery segments are consistent with halothane effects seen in vascular smooth muscle from several other tissues and species. The results of our experiments support the conclusion that the release of intracellular Ca++ from sarcoplasmic reticular stores is responsible for the halothane-induced vasoconstriction that has been observed in this tissue.