Ability of the Tightrope® and percutaneous lateral fabellar suture techniques to control cranial tibial translation.

Objective: To compare the ability of the Tightrope® (TR) cranial cruciate ligament (CCL) technique, percutaneous lateral fabella suture (pLFS) technique, and normal CCL to control cranial tibial translation (CTT).

Study Design: In vitro biomechanical study.

Sample Population: Cadaveric canine pelvic limbs (n = 18 pairs).

Biomechanical comparison of strategies to adjust axial stiffness of a hybrid fixator.

Objectives: To evaluate strategies for increasing the axial stiffness of a hybrid external bone fixator.

Materials And Methods: Type Ia hybrid fixators, consisting of a uniplanar linear component connected to a circular ring, were tested in displacement controlled loading in axial compression. The basic hybrid construct was modified to explore strategies considered to increase fixator stiffness including: decreasing ring diameter, increasing ring thickness, adding pins to the ring fixation, and adding struts between the ring and vertical post components of the device.

Evaluation of composite resin materials for maxillomandibular fixation in cats for treatment of jaw fractures and temporomandibular joint luxations.

Objective: To identify a method of composite application for maxillomandibular fixation (MMF) in cats that ensures the material will remain bonded during convalescence but be easy to remove with a low complication rate.

Study Design: Experimental study.

Sample Population: Feline cadavers (n=88).

Biomechanics of aggressive inline skating: landing and balancing on a grind rail.

Currently, only epidemiological injury data have been reported for the new extreme sport of aggressive inline skating, or trick skating. No studies have examined the biomechanics of this sport, which involves repetitive jumping and landing from railings, ramps, and ledges, often over 1 m in height. We present results of a pilot study that examined the effect of skater experience and lower extremity biomechanics on energy absorption ability, and observed balance strategies used during two basic tricks.

Evaluation of an osteoconductive resorbable calcium phosphate cement and polymethylmethacrylate for augmentation of orthopedic screws in the pelvis of canine cadavers.

Objective: To evaluate the effect of an osteoconductive resorbable calcium phosphate cement (CPC) on the holding power of bone screws in canine pelvises and to compare the effect with that for polymethylmethacrylate (PMMA).

Sample Population: 35 pelvises obtained from canine cadavers.

Procedure: Each pelvis was sectioned longitudinally.

Evaluation of 2 cement techniques for augmentation of stripped 1.5 mm screw sites in the distal metaphysis of feline radii.

Objective: To evaluate the effect of 2 cement augmentation techniques on pullout strength of 1.5 mm screws placed in stripped 1.5 mm screw sites in the distal metaphysis of feline radii.

Synthesis and activity of nonhydrolyzable pseudomonic acid analogues.

Several series of pseudomonic acid analogues have been prepared that incorporate modified functionalities in place of the C1-C3 alpha,beta-unsaturated ester group. The inhibition of isoleucyl-tRNA synthetase and the in vitro activity of these compounds against various Gram-positive and Gram-negative strains are described. Several derivatives showed enzyme inhibition equivalent to or better than that of methyl pseudomonate (3), while lacking the hydrolyzable ester group at C1.

Lysinomicin, a new aminoglycoside antibiotic. II. Structure and stereochemistry.

The structure of lysinomicin, a new aminocyclitol antibiotic, was established as 3-epi-2'-N-(L-beta-lysyl)-4',5'-didehydro-6'-de-C-methylfortimi cin B (1) on the basis of spectral evidence and chemical degradation of the antibiotic. In the course of the degradation of 1, three additional compounds with interesting biological properties were obtained: 3-epi-2'-N-(L-beta-lysyl)-6'-de-C-methylfortimicin B (4), 3-epi-4',5'-didehydro-6'-de-C-methylfortimicin B (6) and 3-epi-6'-de-C-methylfortimicin B (7).

4-N-Aminoacylation of substances derived from lysinomicin.

The preparations of 4-N-glycyllysinomicin and several 4-N-aminoacyl derivatives of compounds prepared from lysinomicin are presented. The new substances have lower antimicrobial activities than the original 4-N-unsubstituted lysinomicin derivatives. This result indicates that the structure-activity relationship observed with fortimicin A and fortimicin B does not apply to the lysinomicin derivatives studied.

Substances derived from 4-de-N-methylfortimicin B.

The preparation of 4-de-N-methylfortimicin A analogs as well as the preparation of 4-de-N-methyl-4-N-(beta-aminoethyl)-4-N-ethylfortimicin B is reported. It was shown that the 4-N-methyl group in fortimicin analogs is essential for antibacterial activity since neither the 4-de-N-methylfortimicin A nor the 4-de-N-methyl-4-N-(beta-aminoethyl)-4-N-ethylfortimicin B exhibited useful biological activity.

4-N-acylfortimicins B and the preparation of fortimicin A from fortimicin B.

Selective 4-N-acylation of fortimicin B (2) has been accomplished by 4-N-acylation of 1,2',6'-tri-N-benzyloxycarbonylfortimicin B (4) followed by hydrogenolysis of the N-protecting benzyloxycarbonyl groups. In this manner, fortimicin B was converted into fortimicin A (1), and a series of 4-N-acylfortimicins B (3) was prepared for antibacterial assay. The key intermediate, 1,2',6'-tri-N-benzyloxycarbonylfortimicin B, was prepared either directly from fortimicin B or by converting fortimicin A into 1,2',6',2''-tetra-N-benzyloxycarbonylfortimicin A (6a), followed by selective hydrolysis of the 4-N-(N-benzyloxycarbonyl)glycyl group of the latter.

4-N-Aminoacylfortimicins E.

The conversion of fortimicin E, a minor metabolite from the Micromonospora olivoasterospora fermentation which also produces fortimicin A and fortimicin B, to four 4-N-aminoacylfortimicins E was accomplished. The new 4-N-aminoacylfortimicins E showed only weak antimicrobial activity against several Gram-negative and Gram-positive microorganisms.

The structures of the m-chloroperbenzoic acid oxidation products of 8,9-anhydroerythromycins A- and B-6,9-hemiacetal and of (8S)-8-hydroxyerythromycin B.

13C-NMR studies have confirmed the structures of (8S)-8-hydroxyerythromycins A- and B-6,9;9,11-acetal proposed by KROWICKI and ZAMOJSKI2,3) for the products of the m-chloroperbenzoic acid oxidation of 8,9-anhydroerythromycins A- and B-6,9-hemiacetal. The preparations of (8S)-8-methylthiomethoxy- and (8S)-8-methoxyerythromycin B-6,9;9,11-acetals are described. The latter are stable in aqueous acetic acid under conditions which convert (8S)-8-hydroxyerythromycin B-6,9;9,11-acetal into (8S)-8-hydroxyerythromycin B.