A Phase 2a Randomized, Double-Blind, Dose-Optimizing Study to Evaluate the Immunogenicity and Safety of a Bivalent DNA Vaccine for Hemorrhagic Fever with Renal Syndrome Delivered by Intramuscular Electroporation.

Hantaan virus (HTNV) and Puumala virus (PUUV) are pathogenic hantaviruses found in Asia and Europe, respectively. DNA vaccines targeting the envelope glycoproteins of these viruses have been constructed and found to elicit neutralizing antibodies when delivered to humans by various technologies including intramuscular electroporation. Here, we report findings from a Phase 2a clinical trial of a combined HTNV/PUUV DNA vaccine delivered at varying doses and administration schedules using the Ichor Medical Systems TriGrid intramuscular electroporation delivery technology. The study was designed to characterize the effects of DNA vaccine dose and number of administrations on the frequency and magnitude of immunological response. Subjects (n = 120) were divided into four cohorts. Cohorts 1 and 2 received a dose of 2 mg of DNA (1 mg per plasmid), and cohorts 3 and 4 received a dose of 1 mg of DNA (0.5 mg per plasmid) each vaccination. Each of the four cohorts received a series of four administrations (days 0, 28, 56 and 168). For cohorts 1 and 3, the DNA vaccine candidate was delivered at each of the four administrations. For cohorts 2 and 4, in order to maintain blinding, subjects received the DNA vaccine on days 0, 56 and 168, but on day 28 received only the phosphate buffered saline vehicle rather the DNA vaccine. Sera were collected on days 0, 28, 56, 84, 140, 168, 196, 252 and 365 and evaluated for the presence of neutralizing antibodies by PUUV and HTNV pseudovirion neutralization assays (PsVNAs). Day 84 was also evaluated by a plaque reduction neutralization test (PRNT). Overall the PsVNA50 geometric mean titers (GMTs) and seropositivity rates among cohorts were similar. Cohort 3 exhibited the highest frequency of subjects that became seropositive to both PUUV and HTNV after vaccination, the highest peak GMT against both viruses, and the highest median titers against both viruses.

Pharmacokinetics of gamithromycin in cattle with comparison of plasma and lung tissue concentrations and plasma antibacterial activity.

The pharmacokinetics (PK) and dose proportionality of gamithromycin (ZACTRAN), a novel azalide, after a single intravenous (i.v.) dose of 3 mg/kg or subcutaneous (s.c.) injection at 3, 6 and 9 mg/kg body weight were studied in 13 male castrate and 13 female Angus cattle. Following i.v. administration, the mean area under the curve extrapolated to infinity (AUC(inf)) was 4.28 +/- 0.536 microgxh/mL, and mean elimination half-life (t(1/2)) was 44.9 +/- 4.67 h, with a large volume of distribution (V(ss)) of 24.9 +/- 2.99 L/kg and a high clearance rate (Cl(obs)) of 712 +/- 95.7 mL/h/kg. For cattle treated with s.c. injection of 3, 6 or 9 mg/kg, mean AUC(inf) values were 4.55 +/- 0.690, 9.42 +/- 1.11 and 12.2 +/- 1.13 microgxh/mL, respectively, and the mean elimination half-lives (t(1/2)) were 51.2 +/- 6.10, 50.8 +/- 3.80 and 58.5 +/- 5.50 h. Gamithromycin was well absorbed and fully bioavailable (97.6-112%) after s.c. administration. No statistically significant (alpha = 0.05) gender differences in the AUC(Inf) or elimination half-life values were observed. Dose proportionality was established based on AUC(Inf) over the range of 0.5 to 1.5 times of the recommended dosage of 6 mg/kg of body weight. Further investigations were conducted to assess plasma PK, lung/plasma concentration ratios and plasma antibacterial activity using 36 cattle. The average maximum gamithromycin concentration measured in whole lung homogenate was 18 500 ng/g at first sampling time of 1 day ( approximately 24 h) after treatment. The ratios of lung to plasma concentration were 265, 410, 329 and 247 at 1, 5, 10 and 15 days postdose. The lung AUC(inf) was 194 times higher than the corresponding plasma AUC(inf). The apparent elimination half-life for gamithromycin in lung was 90.4 h ( approximately 4 days). Antibacterial activity was observed with plasma collected at 6 h postdose with a corresponding average gamithromycin plasma concentration of 261 ng/mL. In vitro plasma protein binding in bovine plasma was determined to be 26.0 +/- 0.60% bound over a range of 0.1-3.0 microg/mL of gamithromycin. The dose proportionality of AUC, high bioavailability, rapid and extensive distribution to lung tissue and low level of plasma protein binding are beneficial PK parameters for an antimicrobial drug used for the treatment and prevention of bovine respiratory disease.

A collaborative approach to developing nursing skills to meet service needs.

Academics, educators and health service managers came together to explore, within their local area, the nature of the perceptions of beginning registered nurses (BRNs) and Nursing Unit Managers (NUMs) to the skills utilised by BRNs within the first six months of practice. A group of 71 BRNs and nine NUMs participated in a cross-sectional survey. BRNs were also asked to rate their preparedness in each particular skill, dependent on the method of teaching--theory/lectures, nursing laboratories and clinical experience. Some 21 skills, relating to medication/fluid administration and skin and wound care, were perceived by 95 per cent or more of the graduates as being used within the first six months. Similar perceptions existed for NUMs and BRNs for 52.4 per cent of the listed skills. Differences in perceptions have led to academics altering the scope of skills being taught and focusing assessment on critical skills for BRNs, and managers increasing awareness among NUMs as to the source of the differences and developing programs to improve clinical interpretation skills. Improvements in the experience of the BRN are likely to occur when all parties work together to bring about positive change. By Barbara Somerville,

MRI angiography of a patient before and during alcohol-induced cluster headache.

A 25-year-old man, subject to bouts of left supraorbital cluster headache on an annual basis over the previous 8 years, volunteered for MRI angiography during an active period. Studies were conducted before and during a typical cluster headache attack induced by alcohol. MRI angiography failed to show dilatation of the ophthalmic artery on either the symptomatic side, or the non-symptomatic side during headache, nor was there observed any dilatation of the anterior cerebral arteries on either side.

Two-color flow cytometric measurement of DNA distributions of rat megakaryocytes in unfixed, unfractionated marrow cell suspensions.

The ploidy distribution of megakaryocytes shifts in response to platelet demand and thus provides a sensitive index of megakaryocytopoiesis. Flow cytometry (FCM) is a potentially valuable method for rapid determination of ploidy distributions of megakaryocyte populations; however, because megakaryocytes constitute only a very small proportion of the cells in unfractionated marrow, other rare events, such as cell clumping, complicate FCM analysis. We describe the measurement of cellular DNA distributions of megakaryocytes by two-color FCM in unfixed, unfractionated marrow--a method based on the resistance of megakaryocytes to hypotonic lysis in the cold for at least 2 days. Specific platelet antiserum was used to label megakaryocytes by indirect immunofluorescence with fluorescein (green fluorescence), and DNA was stained with propidium iodide (red fluorescence) in hypotonic citrate solution. The ploidy distribution of megakaryocytes was selectively determined with two-color, green-gated FCM, with which the red and green fluorescence of all cells is analyzed, but only the red fluorescence (DNA content) of cells that specifically bound the platelet antibody is recorded. We demonstrate that this method can readily detect changes in megakaryocyte DNA distributions due to experimental thrombocytopenia or platelet hypertransfusion and, therefore, should be useful for both experimental and clinical investigations of megakaryocytopoiesis.

Treatment of migraine attacks with an analgesic combination (Mersyndol).

The relief of acute migraine attacks with an analgesic/antihistamine combination containing paracetamol, codeine phosphate, doxylamine succinate and caffeine (Mersyndol) compared with that achieved with a placebo has been studied in a double-blind, crossover trial. Mersyndol emerged as significantly better than placebo in the complete relief of migraine pain, and was clearly superior to placebo in partially relieving the pain of migraine. These results suggest that it could be a useful alternative to ergotamine, and a comparative trial with ergotamine is suggested. Side effects with this combination were fairly common but mild, and consisted mainly of drowsiness caused by the antihistamine component.

Platelet-bound and free serotonin levels in jugular and forearm venous blood during migraine.

The level of serotonin in platelets and free in plasma has been determined in jugular and forearm venous blood before and during migraine attacks in six women. A significant fall in platelet serotonin was observed in five subjects and was accompanied by a significant fall in plasma free serotonin in the four subjects for whom data concerning free serotonin levels were available. There was no significant difference between jugular and forearm blood in respect to either platelet-bound or free serotonin in the headache-free phase, and during migraine, the values for jugular and forearm blood were parallel. The significance of these findings in relationship to the serotonin theory of migraine is discussed.

Estrogen-withdrawal migraine. I. Duration of exposure required and attempted prophylaxis by premenstrual estrogen administration.

The minimum exposure to estrogen required to cause estrogen-withdrawal migraine has been studied by giving long-acting estradiol valerate to four women and short-acting estradiol benzoate to two women. It was found that several days of exposure to high estrogen levels were needed to cause migraine on estrogen withdrawal. Oral administration of estrogen supplements in the form of estradiol valerate or as conjugated equine estrogens during the premenstrual phase in four women did not significantly affect plasma levels of estradiol, nor was it effective in preventing menstrual migraine.

Estrogen-withdrawal migraine. II. Attempted prophylaxis by continuous estradiol administration.

Prophylaxis of menstrual migraine was attempted in five women, using estradiol implants. The treatment was successful in suppressing ovulation and in producing high, although fluctuating, levels of estradiol in the plasma. Clinically this was associated with severe menstrual disturbance. The regular periodicity of the headaches was lost, but clinical benefit was unpredictable, with some patients actually experiencing more headaches than before the treatment. The administration of progesterone against a background of prolonged exposure to high estrogen levels did not provoke migraine, nor in any case did its subsequent withdrawal result in migraine. These findings cast further doubt on the importance of progesterone withdrawal in the etiology of menstrual migraine.