In Vivo Inhibition of Acute Platelet-Dependent Thrombosis in a Baboon Model by BAY U3405, a Thromboxane A2-Receptor Antagonist

Bay U3405 is a thromboxane A2 (TxA2)-receptor antagonist that inhibits the binding of TxA2 to its target cells. The aim of this study was to determine if Bay U3405 could be used to inhibit arterial thrombosis. A thrombogenic de vice, consisting of uncrimped Dacron vascular graft material (0.5 cm2) built into the wall of silicone rubber tubing with 4 mm inside diameter, was exposed to native flowing blood under arterial blood flow conditions (100-140 ml/min) by interposing the devices as extension segments into permanent femoral arteriovenous shunts implanted in baboons. Thrombus formation was quantified in vivo by measuring the deposition of 111In-labelled platelets onto the graft material with a scintillation camera. In six baboons, a bolus injection of Bay U3405, calculated to attain an initial plasma concentration of 300 ng/ml, reduced the maximum thrombus formation measured over a 2 h study period. Platelet deposition was reduced by 33 ± 14% (SD) at 2 h as compared to control studies done in the same baboons. The accumulation of additional platelets onto a thrombus that was allowed to form for 1 h, was reduced by 58 ± 28% at 2 h. Ex vivo platelet aggregation in response to ADP, activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT) were not affected by the treatment. Ex vivo platelet aggregation in response to collagen was markedly inhibited for 2 h after treatment. The results demonstrated that selective blocking of the TxA2-receptor on platelets reduced platelet-dependent thrombus formation and the accumulation of additional platelets in a freshly formed thrombus. This may provide a viable approach for preventing excessive thrombus formation in patients undergoing arterial reconstructive surgery.

Effectiveness of maternal pertussis vaccination in preventing infection and disease in infants: The NSW Public Health Network case-control study

BACKGROUND

Infants are at the highest risk of severe complications - including death - as a result of pertussis infection. Controlling pertussis in this group has been challenging, particularly in those too young to be vaccinated. Following revised national recommendations in March 2015, the state of New South Wales, Australia, introduced a funded maternal vaccination campaign at 28 - 32 weeks of gestation using a 3-component tetanus-diphtheria-acellular pertussis vaccine (dTpa; Boostrix, GSK). This study aimed to assess the effectiveness of maternal vaccination and add to the growing body of evidence for this strategy.

METHODS

A 1:1 matched case-control study was conducted between 16 August 2015 and 17 August 2016. Cases were laboratory or doctor notified, laboratory confirmed (nucleic acid testing or culture) and aged <6 months at onset. Each control infant was randomly selected from public hospital births in the same geographical area in the period up to 3 days before and after the case's birthdate. Odds ratios (OR) were calculated using conditional logistic regression. Vaccine effectiveness (VE) was calculated as 1 - OR.

FINDINGS

In total, 117 cases and 117 controls were recruited. The overall VE estimate was non-significantly protective for infants <6 months old (VE 39%, 95% CI -12 to 66%). Higher VE was observed for infants <3 months old (VE 69%, 95% CI 13-89%) and against hospitalisation (VE 94%, 95% CI 59-99%).

INTERPRETATION

Maternal pertussis vaccination with a 3-component acellular vaccine was found to be highly effective at preventing severe disease in infants, but was less effective at preventing disease which did not require hospitalisation. The overall VE reported in this study was lower than in prior studies and suggests that maternal vaccination, while an effective strategy at preventing severe pertussis, is less effective at protecting against infection or mild disease.

Engineering controls in veterinary oncology: A survey of 148 ACVIM board-certified oncologists and environmental surveillance in 20 specialty hospitals

Engineering controls (EC, facility and equipment barriers between hazards and people) are used to avoid exposure to chemotherapy drugs. In this study, American College of Veterinary Internal Medicine board-certified veterinary oncologists were surveyed about their use of containment primary EC (C-PEC) and supplemental EC (closed system transfer devices, CSTD). The survey was completed by 148 (38%) of practicing diplomates. All used EC. Both C-PEC and CSTD were used at 92% of hospitals; however, US Pharmacopoeial Convention Chapter <800> (USP <800>) standards were met at only 19% of hospitals and oncologists did not know the type of C-PEC at 18% of hospitals. Next, surface contamination and EC use were assessed with environmental surveillance for carboplatin, cyclophosphamide, doxorubicin, and vincristine in 20 veterinary specialty hospitals using a commercially available kit. No contamination with carboplatin, doxorubicin, or vincristine was detected, however, there was contamination with cyclophosphamide at 4 hospitals. Based on this study, most veterinary oncologists use C-PEC and CSTD, but few meet USP <800> standards. Current measures appear effective for preventing contamination with IV drugs, but additional measures are needed for oral drugs.

Comparison of lidocaine and lidocaine-epinephrine for the paravertebral brachial plexus block in dogs

OBJECTIVE

To compare the motor and sensory block efficacy and duration of a modified paravertebral brachial plexus block (PBPB) after administration of lidocaine alone (LI) or combined with epinephrine (LE).

STUDY DESIGN

Prospective, randomized, blinded, crossover study.

ANIMALS

A total of eight healthy female Beagle dogs.

METHODS

Under general anesthesia, modified PBPB was performed on the left thoracic limb using neurostimulation and/or ultrasound guidance to administer lidocaine (2 mg kg^-1; 0.2 mL kg^-1) either alone (treatment LI, n = 10) or with epinephrine (1:100,000; treatment LE, n = 9). Sensory block was evaluated through reaction to a painful mechanical stimulus applied at five sites on the limb. Motor block effect was evaluated according to visual gait assessments and thoracic limb vertical force measurements under dynamic and static conditions. Data were analyzed using repeated-measures generalized estimating equations. All statistical tests were performed two-sided at the α = 0.05 significance threshold.

RESULTS

The duration of sensory block did not differ significantly between treatments. Visible gait impairment was more persistent in LE than in LI (118 ± 63 minutes for LI and 163 ± 23 minutes for LE; mean ± standard deviation) (p = 0.027). At nadir value, dynamic peak vertical force was lower in LE than in LI (p = 0.007). For both dynamic and static evaluations, the nadir and the return to baseline force were delayed in LE (return to normal at 180-200 minutes) when compared with LI (130-140 minutes) (p < 0.005).

CONCLUSIONS AND CLINICAL RELEVANCE

The addition of epinephrine to lidocaine prolonged the duration and increased the intensity of the regional block, as verified by visual gait assessment and kinetic analysis. No significant difference was noted between treatments regarding sensory blockade. Kinetic analysis could be useful to evaluate regional anesthetic effect in dogs.

Use of CT to evaluate and compare intranasal features in brachycephalic and normocephalic dogs

OBJECTIVES

To evaluate and compare nasal mucosal contact, septal deviation and caudal aberrant nasal turbinates in brachycephalic and normocephalic dogs using computed tomography.

METHODS

Dogs without nasal disease and having undergone computed tomography scan of the head (plica alaris to the cribiform plate) were retrospectively selected and divided into brachycephalic and normocephalic groups. Eighteen brachycephalic and 32 normocephalic dogs were included. Anatomic criteria were used to locate predetermined pairs of intranasal structures and nasal mucosal contact was described as present or absent for each site. Septal deviations were identified and measured using angle of septal deviation. Caudal aberrant nasal turbinates were identified and categorised when present.

RESULTS

Prevalence of nasal mucosal contact was significantly higher in brachycephalic dogs. No significant difference was seen in prevalence or in angle of septal deviation between groups. Prevalence of caudal aberrant nasal turbinates was significantly higher in brachycephalic dogs.

CLINICAL SIGNIFICANCE

Nasal mucosal contact and caudal aberrant nasal turbinates were significantly more prevalent in brachycephalic dogs than in normocephalic dogs in our study. Computed tomography can be a valuable aid in obtaining data on nasal mucosal contact, caudal aberrant nasal turbinates and septal deviations. Combination of computed tomography with endoscopy and functional airway testing would be useful to further evaluate the correlation between intranasal features and symptoms of brachycephalic airway syndrome.

Changes of Skin Microcirculation in Patients with Chronic Venous Insufficiency Assessed by Laser Doppler Fluxmetry and Transcutaneous Oxymetry

Objective:

To evaluate whether microcirculatory disturbances of the skin in patients with chronic venous insufficiency are a generalized phenomenon or restricted to visible skin changes.

Design:

Open, prospective study in patients and healthy, age-matched subjects.

Setting:

Department of Angiology, Hannover Medical School.

Patients:

Seventy-one patients with chronic venous insufficiency.

Measurements:

Transcutaneous oxygen pressure (tc Po2) at electrode core temperatures of 37°C and 44°C and laser Doppler flux (LDF) were measured simultaneously in different regions of the legs.

Results:

On the forefoot, tc Po2 (37°C) at rest and tc Po2 (44°C) during arterial ischaemia were significantly higher in patients ( P<0.05), increasing with the severity of chronic venous insufficiency.

Conclusions:

Cutaneous capillary flow on the forefoot is increased in patients with chronic venous insufficiency, demonstrating the general effect of venous hypertension.

Healthcare professional requirements for the care of adult diabetes patients managed with insulin pumps in Australia

BACKGROUND

Healthcare professional (HCP) time supporting insulin pump therapy (IPT) has not been documented, yet it is important in planning and allocating resources for effective care.

AIM

This study aims to determine HCP time spent in IPT patient care to inform resource planning for optimal IPT delivery.

METHODS

Twenty-four Australian adult IPT-experienced institutions (14 government funded, seven private, three both) collected data between April 2012 and January 2013 prospectively, including: patient demographics, HCP classification, purpose of HCP-patient interaction, interaction mode and HCP time with the patient. A subset of patients was tracked from pre-pump education until stable on IPT.

RESULTS

Data on 2577 HCP-adult patient interactions (62% face-to-face, 29% remote, 9% administrative) were collected over 12.2 ± 6.4 weeks for 895 patients; age 35.4 ± 14.2 years; 67% female; 99% type 1 diabetes, representing 25% of all IPT patients of the institutions. Time (hours) spent on IPT interactions per centre per week were: nurses 5.4 ± 2.8, dietitians 0.4 ± 0.2 and doctors 1.0 ± 0.5. IPT starts accounted for 48% of IPT interaction time. The percentage of available diabetes clinic time spent on outpatient IPT interactions was 20.4%, 4.6% and 2.7% for nurses, dietitians and doctors respectively. Fifteen patients tracked from pre-pump to stabilisation over 11.8 ± 4.5 weeks, required a median (range) of 9.2 (3.0-20.9), 2.4 (0.5-6.0) and 1.8 (0.5-5.4) hours per patient from nurses, dietitians and doctors respectively.

CONCLUSIONS

IPT patient care represents a substantial investment in HCP time, particularly for nurses. Funding models for IPT care need urgent review to ensure this now mainstream therapy integrates well into healthcare resources.

Cryptococcal nasopharyngeal polypoid mass in a cat

Case summary

An indoor 9-year-old castrated male domestic cat was referred with a 4 month history of increased upper airway noise. Computed tomography revealed a nasopharyngeal polypoid mass, which was removed endoscopically with basket forceps. Histopathology was compatible with a polypoid granulomatous pharyngitis with Cryptococcus-like organisms. This was supported by a positive serum latex cryptococcal antigen agglutination test (LCAT). Minimal inflammation of the nasal tissue was noted on histopathology, with no evidence of fungus. Following endoscopic removal of the mass, the patient was treated with systemic antifungal medication (itraconazole). One year after diagnosis, the LCAT titer was negative and the cat remained free of clinical signs.

Relevance and novel information

This case report emphasizes the importance of considering Cryptococcus species as a potential etiology in cats presented with signs of nasopharyngeal obstruction with an isolated nasopharyngeal polypoid mass, even if kept indoors.

Leuco-crystal-violet micelle gel dosimeters: I. Influence of recipe components and potential sensitizers

Radiochromic leuco crystal violet (LCV) micelle gel dosimeters are promising three-dimensional radiation dosimeters because of their spatial stability and suitability for optical readout. The effects of surfactant type and surfactant concentration on dose sensitivity of LCV micelle gels are tested, demonstrating that dose sensitivity and initial colour of the gel increases with increasing Triton x-100 (Tx100) concentration. Using Cetyl Trimethyl Ammonium Bromide (CTAB) in place of Tx100 produces gels that are nearly colourless prior to irradiation, but reduces the dose sensitivity. The separate effects of Tri-chloro acetic acid concentration and pH are investigated, revealing that controlling the pH near 3.6 is crucial for achieving high dose sensitivity. The sensitizing effect of chlorinated species on dose sensitivity is tested using 2,2,2-trichloroethanol (TCE), chloroform, and 1,1,1-trichloro-2-methyl-2-propanol hemihydrate. TCE gives the largest improvement in dose sensitivity and is recommended for use in micelle gel dosimeters because it is less volatile and safer to use than chloroform. Preliminary experiments on a new gel containing CTAB as the surfactant and TCE show that this new gel gives a dose sensitivity that is 24% higher than that of previous LCV micelle gels and is nearly colourless prior to irradiation.