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A Gibb

Publications and source records attributed to A Gibb.

15 recordsLinked to original sources
PubMed1997

Valaciclovir for the suppression of recurrent genital HSV infection: a placebo controlled study of once daily therapy. International Valaciclovir HSV Study Group.

OBJECTIVE: To determine the efficacy and safety of once daily valaciclovir for the suppression of recurrent genital herpes simplex virus (HSV) infection in immunocompetent patients. METHODS: 382 otherwise healthy patients with a history of frequently recurring genital HSV infection (eight recurrences per year) were randomly allocated to receive either oral valaciclovir (500 mg once daily) or placebo (3:1 ratio) for 16 weeks or until the first genital HSV recurrence, whichever occurred first. Patients were clinically assessed at regular intervals and also if they experienced a recurrence. Safety was evaluated through adverse experience reporting and monitoring of haematology and biochemistry variables. On completion of the double blind phase, patients were eligible for follow up to a maximum of 48 weeks' treatment with open label valaciclovir (500 mg once daily) for further safety monitoring. The results from the double blind phase of the study are reported here. RESULTS: A significant difference was detected between valaciclovir and placebo in the time to first recurrence of genital HSV infection. The hazard ratio [95% confidence interval] for valaciclovir v placebo was 0.155 [0.112, 0.214], p < 0.0001. Valaciclovir prevented or delayed 85% of the recurrences that would have occurred with placebo. After 16 weeks (day 112) with treatment, 69% of patients receiving valaciclovir were recurrence free compared with only 9.5% of patients assigned to placebo. The safety profiles of valaciclovir and placebo were comparable, with adverse experiences being infrequent and generally mild. CONCLUSION: This study has demonstrated that once daily valaciclovir (500 mg), is highly effective and well tolerated for the suppression of recurrent genital HSV infection. Once daily dosing with valaciclovir provides a more convenient dosing regimen than the more frequent aciclovir regimens.

Acyclovir↗
PubMed1997

Valaciclovir versus aciclovir in patient initiated treatment of recurrent genital herpes: a randomised, double blind clinical trial. International Valaciclovir HSV Study Group.

OBJECTIVE: To compare the efficacy and safety of twice daily valaciclovir with five times daily aciclovir in the treatment of an episode of recurrent genital herpes simplex virus (HSV) infection in immunocompetent individuals. METHODS: 739 patients with a history of recurrent genital HSV infection received either oral valaciclovir (500 mg twice daily) or aciclovir (200 mg five times daily) for 5-days for treatment of their next recurrent episode in a controlled, randomised, double blind trial. Patients self initiated therapy at the first signs and/or symptoms of the HSV recurrence, then were assessed in clinic on five occasions over 7 days, and twice weekly thereafter until lesions had healed. Safety was evaluated through adverse experience reports and haematology and biochemistry monitoring. RESULTS: No significant differences were detected between valaciclovir and aciclovir for the primary endpoint, the duration of all signs and symptoms which included lesion healing and pain/discomfort. The hazard ratio [95% confidence interval] for valaciclovir v aciclovir was 0.93 [0.79, 1.08]. Lesion healing time was similar in each treatment group (hazard ratio valaciclovir v aciclovir 0.96 [0.80, 1.14]). The odds ratio of valaciclovir v aciclovir in preventing the development of vesicular/ulcerative lesions was 1.08 [0.82, 1.42]. Percentages of patients in whom all HSV cultures were negative were similar in the valaciclovir and aciclovir groups at 59% and 54% respectively; for patients having equal to or more than one positive culture result after treatment initiation, cessation of virus shedding was similarly rapid for the two treatments (hazard ratio 0.98 [0.75, 1.27]). The safety profiles of valaciclovir and aciclovir were comparable with adverse experiences being infrequent and generally mild. CONCLUSION: This study has demonstrated that valaciclovir 500 mg twice daily is equivalent in efficacy to aciclovir 200 mg five times daily as episodic treatment of recurrent genital HSV infection. Valaciclovir maintains the established efficacy and safety of aciclovir but offers a much more convenient twice daily dosing regimen.

Acyclovir↗
PubMed1997

Do flatfish feed like other fishes? A comparative study of percomorph prey-capture kinematics.

The kinematics of prey capture in two bilaterally asymmetrical pleuronectiform flatfish species (Pleuronichthys verticalis and Xystreurys liolepis) and two symmetrical percomorph species (Lepomis macrochirus, a centrarchid, and Cheilinus digrammus, a labrid) were compared to test the hypothesis that flatfish have distinct prey-capture kinematics from those quantified for other percomorph fishes. Size-matched individuals of both flatfish species were video-taped feeding using a high-speed video system. Cephalic displacement and timing variables were quantified and compared with data from similarly sized L. macrochirus and C. digrammus previously collected by other researchers using similar experimental methodology. Nested multivariate analyses of variance indicated that there was no significant difference in prey-capture kinematics between flatfish and non-flatfish taxa, but that prey-capture kinematics did differ among the four taxa. Multiple nested analyses of variance revealed that the taxa differed in 7 of 11 kinematic variables. Post-hoc tests and comparisons with other fish taxa suggest that individuals of P. verticalis possess an unusual combination of prey-capture kinematics including large hyoid depression, large neurocranial rotation, large upper jaw protrusion and small gape. Previous research has suggested that this combination of traits is associated with suction-based prey capture. Correspondingly, the ram&shy;suction index calculated for P. verticalis is more negative (indicating a greater use of suction) than that calculated for the other taxa. When homologous kinematic variables are compared across these four taxa, flatfish do not appear to have similar prey-capture kinematics. However, both flatfish species are distinct from the two symmetrical percomorph species in their asymmetrical jaw movements.

Journal Article↗
PubMed1997

The long-term neuropsychological outcome of herpes simplex encephalitis in a series of unselected survivors.

This study sought to produce a cognitive profile of herpes simplex encephalitis (HSE) survivors from a large group of definitively diagnosed, acyclovir-treated participants. Results from 22 adults who underwent a battery of neuropsychological tests indicated anterograde memory dysfunction to be the most severe and common deficit (although the variation was great), with less severe and less frequent impairments in the areas of retrograde memory, executive functions, and language functioning. Overall, neuropsychological outcome was unimpaired in six participants, mildly impaired in thirteen, moderately impaired in one, severely impaired in two. Older participants and those with a lower level of consciousness before the start of treatment produced poorer scores on certain aspects of cognitive outcome (p < 0.05). A significantly better cognitive outcome was found in participants for whom there was a short delay (fewer than 5 days) between symptom onset and acyclovir treatment compared with those participants for whom there was a longer delay. The two children in the study had disparate results on most tests, the exception being those assessing memory functioning on which both children had scores at population norms. On a naming task designed to explore category-specific knowledge deficits, the adults as a group made more errors on pictures of living things than nonliving things (matched pair-wise for word frequency and visual familiarity), although this difference disappeared on a smaller subset of pictures also matched for visual complexity.

Acyclovir↗
PubMed1996

Characterization of a stable L-form of the fish pathogen Aeromonas salmonicida.

A stable L-form of Aeromonas salmonicida, which resulted from induction with benzylpenicillin, contained more of an outer membrane protein, with an estimated molecular weight of 40 kDa but less of 47.9 and 38 kDa proteins, than did parental walled cells. In addition, from Western blots, two protein bands reacted strongly with a polyclonal antiserum. The antiserum did not react demonstrably with the band detected in the L-forms on the gels.

Aeromonas↗
PubMed1996

The kinematics of prey capture in Xystreurys liolepis: do all flatfish feed asymmetrically?

Previous research has shown that one species of flatfish displays several functional asymmetries of the head and jaws during prey capture. However, it is not known whether the functional asymmetries observed for this species are common to all flatfishes. In order to determine whether functional asymmetry is present in other flatfish taxa, prey-capture behavior was examined in a species of flatfish with little cephalic morphological asymmetry, Xystreurys liolepis (Pleuronectiformes: Paralichthyidae). In addition, X. liolepis is one of a few species of flatfish in which both typical (sinistral) and reversed (dextral) individuals are commonly found. Five individuals (two dextral and three sinistral) of X. liolepis were video-taped feeding at 250 fields s-1 in order to quantify prey-capture kinematics. These data were used to test two hypotheses: (1) that typical and reversed-symmetry individuals have identical prey-capture kinematics, and (2) that X. liolepis exhibit no functional asymmetry during prey capture because they have little morphological asymmetry. Analysis of prey capture indicates that the kinematic variables measured for sinistral and dextral individuals are statistically indistinguishable. In addition, X. liolepis do not exhibit the same suite of functional asymmetries that has been found in a flatfish species with more extreme cephalic morphological asymmetry (Pleuronichthys verticalis). However, asymmetrical anterior movement of the ventral portion of the maxilla does occur in X. liolepis during mouth opening. Examination of osteological preparations and cleared and stained individuals indicates that the maxilla is asymmetrical in length in this species. A simple model indicates that the differential length of the maxilla is sufficient to explain the observed functional asymmetry during prey capture. These results suggest that certain morphological asymmetries of the jaws of flatfishes are modifications for specialized prey-capture behaviors.

Journal Article↗
PubMed1995

Kinematics of prey capture in a flatfish, Pleuronichthys verticalis

Hornyhead turbot, Pleuronichthys verticalis (Pleuronectiformes: Pleuronectidae), are morphologically asymmetrical teleosts with substantial bilateral asymmetry in the neurocranium, suspensorium and anterior jaws. In order to quantify the kinematics of prey capture and to test for functional bilateral asymmetries, four individuals of this species were video-taped feeding using a high-speed video system at 200 fields s-1. Frame-by-frame analysis revealed several features not commonly found in prey capture behavior of previously studied ray-finned fishes. These features include (1) extreme lateral compression of the suspensorium and opercular series prior to mouth opening, indicating the consistent presence of a preparatory phase during feeding, (2) apparent dissociation of hyoid retraction and lower jaw depression, (3) prolonged hyoid retraction throughout much of the feeding cycle, and (4) concomitant dorsal rotation of the neurocranium and closing of the jaws. P. verticalis also demonstrate a significant degree of functional bilateral asymmetry during prey capture. When approaching prey, fish flex their heads towards the ocular (anatomically the right) side of the body. During prey capture, their jaws bend out of the midline towards the blind (left) side. Comparisons of the displacement and timing for movements of homologous anatomical features on the ocular and blind sides of the head reveal that maximum gape is always larger on the blind side of the head than on the ocular side. In contrast, other kinematic variables measured are similar on both sides of the head. These results suggest that P. verticalis possess unique functional features of prey capture behavior and that morphological bilateral asymmetry of the head and jaws is associated with, and perhaps causally related to, the functional bilateral asymmetry present during feeding.

Journal Article↗
PubMed1994

KINEMATICS OF PECTORAL FIN LOCOMOTION IN THE BLUEGILL SUNFISH LEPOMIS MACROCHIRUS

The pectoral fins of ray-finned fishes are flexible and capable of complex movements, and yet little is known about the pattern of fin deformation during locomotion. For the most part, pectoral fins have been modeled as rigid plates. In order to examine the movements of different portions of pectoral fins, we quantified the kinematics of pectoral fin locomotion in the bluegill sunfish Lepomis macrochirus using several points on the distal fin edge and examined the effects of swimming speed on fin movements. We simultaneously videotaped the ventral and lateral views of pectoral fins of four fish swimming in a flow tank at five speeds ranging from 0.3 to 1.1 total lengths s-1. Four markers, placed on the distal edge of the fin, facilitated field-by-field analysis of kinematics. We used analyses of variance to test for significant variation with speed and among the different marker positions. Fin beat frequency increased significantly from 1.2 to 2.1 Hz as swimming speed increased from 0.3 to 1.0 total lengths s-1. Maximal velocities of movement for the tip of the fin during abduction and adduction generally increased significantly with increased swimming speed. The ratio of maximal speed of fin retraction to swimming speed declined steadily from 2.75 to 1.00 as swimming speed increased. Rather than the entire distal edge of the fin always moving synchronously, markers had phase lags as large as 32 with respect to the dorsal edge of the fin. The more ventral and proximal portions of the fin edge usually had smaller amplitudes of movement than did the more dorsal and distal locations. With increased swimming speed, the amplitudes of the lateral and longitudinal fin movements generally decreased. We used two distal markers and one basal reference point to determine the orientation of various planar fin elements. During early adduction and most of abduction, these planar fin elements usually had positive angles of attack. Because of fin rotation, angles of attack calculated from three-dimensional data differed considerably from those estimated from a simple lateral projection. As swimming speed increased, the angles of attack of the planar fin elements with respect to the overall direction of swimming approached zero. The oscillatory movements of the pectoral fins of bluegill suggest that both lift- and drag-based propulsive mechanisms are used to generate forward thrust. In addition, the reduced frequency parameter calculated for the pectoral fin of Lepomis (sigma=0.85) and the Reynolds number of 5x10(3) indicate that acceleration reaction forces may contribute significantly to thrust production and to the total force balance on the fin.

Journal Article↗
PubMed1993

Effect of thiol compounds on human complement component C4.

Thiol compounds have been investigated as inhibitors of the covalent binding reaction of human complement protein C4 using Sepharose-C1s as a combined activating and binding surface. o- and p-substituted aminothiophenols are equally effective inhibitors, whereas the m-substituted compound is a less potent inhibitor. The anti-hypertensive drug captopril is also shown to inhibit the covalent binding reaction. A comparison of the effects of these compounds on the covalent binding reaction of isolated C4A and C4B has been made. Results suggest that a Pro-to-Leu substitution in C4B is likely to account for the differences in inhibitory potency of C4B compared with C4A observed with the aromatic inhibitors.

Aminophenols↗