Analysis of mitral valve morphology in dogs undergoing mitral valve repair with three-dimensional transesophageal echocardiography.

INTRODUCTION: Information about real-time three-dimensional (3D) transesophageal echocardiography (TEE) for the evaluation of canine mitral valve morphology is lacking in veterinary medicine. OBJECTIVES: To evaluate the feasibility of 3D TEE for the evaluation of canine mitral valves and whether there was a difference in mitral valve morphology between American College of Veterinary Internal Medicine (ACVIM) stages. ANIMALS: Thirty-one dogs were evaluated, including nine dogs classified as ACVIM stage B2, 15 as stage C, and seven as stage D. MATERIALS AND METHODS: Three-dimensional TEE was performed after anesthetic induction for mitral valve surgery, and the 3D geometry of the mitral valve apparatus was measured. RESULTS: The intraclass correlation coefficient was good in both inter- and intraobserver analyses of the 3D measurements of mitral valve annulus geometry and excellent in both inter- and intraobserver analyses in the 3D measurements of mitral valve annular and leaflet sizes. Annulus height to commissural width ratio of stage D dogs showed significantly lower values than B2 dogs (B2: 14.2% [9.1-20.5%]; C: 10.6% [6.5-24.1%]; D: 9.5% [4.7-13.8%]). The aortic-mitral angle of stages C and D were significantly flatter than stage B2 (B2: 122.32 ± 9.39; C: 133.66 ± 8.43; D: 140.70 ± 10.70). CONCLUSIONS: Real-time 3D echocardiography using TEE is a feasible method to evaluate the morphology of the mitral valve in dogs. The saddle shape of the mitral annulus and aortic-mitral angle were flatter in stage D. Further studies are required to understand the pathology of mitral valve disease in dogs.

Surgical correction for sinus venosus atrial septal defect with partial anomalous pulmonary venous connection in a dog.

A 5-year-old male toy poodle was referred for corrective surgery of an atrial septal defect. A sinus venosus-type atrial septal defect (ASD) with partial anomalous venous connection, suspected pulmonary hypertension, and pulmonary edema was confirmed by radiography, echocardiography, and cardiac computed tomography. Thoracic radiographs showed right heart enlargement. Echocardiography revealed right atrial and ventricular dilatation with mild flattening of the interventricular septum. Left-to-right shunt flow through the ASD was observed on color Doppler examination. Surgical correction of the sinus venosus ASD with a partial anomalous pulmonary venous connection was performed under cardiopulmonary bypass. A follow-up evaluation at 1 year after surgery showed resolution of the right-sided volume overload and no evidence of recurrence of ASD. Complications were not observed. Our findings indicate that surgical correction under cardiopulmonary bypass is a valid treatment option for an ASD with a partial anomalous pulmonary venous connection.

Transcellular relocation of tetrahydrobiopterin across Caco-2 cells: a model study of tetrahydrobiopterin absorption through epithelial cells of intestinal mucosa.

Oral administration of tetrahydrobiopterin (BH(4)) has been known to be effective in treating BH(4)-deficient patients. It has long been established that BH(4) is absorbed by the intestinal mucosa. However, the mechanism for translocation of BH(4) across epithelial cells has not been elucidated. In order to study BH(4) transport mechanisms, Caco-2 cells were employed in this study as an epithelial cell model. Caco-2 cells were cultured (2 x 10(4) cells/0.3 cm(2) well) for 21 days in a 24-well format using Transwell, a porous membrane-based culture dish, at which point they had established themselves as a tight sheet with a definite polarity. When BH(4) (100 micromol/L) was given to cells from the apical side, a considerable translocation toward their basolateral side was noted. The rate of BH(4) movement was around 150 pmol/h per well. This was comparable to the highest rate of BH(4) uptake or its release so far obtained using a monolayer culture of Caco-2 cells on an ordinary plastic plate. The transcellular movement of BH(4) across the polar culture on the porous membrane was effectively prevented by benzbromarone (10 micromol/L), a well known inhibitor of a group of transporters including urate transporter (URAT1), organic anion transporters (OATs), and multidrug-resistance-associated proteins (MRPs). It was thus concluded that in Caco-2 cells, BH(4) moved across the cell interior in a rapid ligand-specific manner that was driven by a transporter.

Tetrahydrobiopterin in intestinal lumen: its absorption and secretion in the small intestine and the elimination in the large intestine.

In treating hereditary deficiency of tetrahydrobiopterin (BH(4)), supplementation with BH(4) might be the ultimate choice of therapy. Oral administration of BH(4) has been believed to be inefficient owing to poor absorption of BH(4) in the intestine. In this study, we found a considerable amount of BH(4) as well as its oxidized pterins in the ingredients of intestinal lumen of mice when they were served food that did not contain significant amounts of biopterin. Ligation of the biliary duct led to significant decrease in luminal biopterin. Supplementation of BH(4) either by intraperitoneal administration of sepiapterin or of 6RBH(4) ((6R)-L-erythro-5,6,7,8-tetrahydrobiopterin) increased the BH(4) content in the intestinal lumen with a slight delay after the rise of blood BH(4). In these mice, biopterin appeared in the large intestine, caecum and colon, 2 h after the administration. The appearance of BH(4) in the large intestine was accompanied by a large amount of pterin (2-amino-4-hydroxypteridine). The amounts of biopterin + pterin that appeared in the large intestine after intraperitoneal administration of BH(4) were not greater than those found after oral administration at the same dose. When the mice were treated with a large dose of antibiotics prior to the BH(4) administration, the amount of biopterin increased in the caecum but the amount of pterin decreased greatly. These results suggested that a large proportion of BH(4) administered moved to the large intestine, where most biopterin was decomposed presumably by enteric bacteria. Nonetheless, most of the orally administered biopterin was taken up by the small intestine and the amount of biopterin reaching the large intestine was almost the same as that which appeared after direct injection of 6RBH(4) into the peritoneal cavity.

Low-molecular-mass proteins in cyanobacterial photosystem II: identification of psbH and psbK gene products by N-terminal sequencing.

The O2-evolving photosystem II core complex was isolated from a thermophilic cyanobacterium, Synechococcus vulcanus Copeland. Analysis by SDS-polyacrylamide gel electrophoresis revealed that the complex contained at least seven low-molecular-mass proteins in addition to the well characterized CP47 apoprotein, CP43 apoprotein, 33 kDa extrinsic protein, D1 protein, D2 protein and large subunit of cytochrome b-559. The separation of these low-molecular-mass proteins were very similar between cyanobacterial and higher plant PS II. N-terminal sequences of the 6.5 kDa and 3.9 kDa proteins of cyanobacterial core complex were determined after blotting to a polyvinylidene difluoride membrane. The sequence of the 6.5 kDa protein showed high homology with an internal sequence of plant psbH gene product, so-called 10 kDa phosphoprotein, but did not conserve the Thr residue which is specifically phosphorylated in plants. The sequence of the 3.9 kDa protein corresponded to the K protein of higher plants (mature form of psbK gene product). These results indicate that the products of both psbH and psbK genes are present in cyanobacterial PS II as well as being associated with the O2-evolving core complex.

Stable-isotope methodology for the bioavailability study of phenytoin during multiple-dosing regimens.

With the highly sensitive and specific gas chromatography-mass spectrometry (GC-MS), plasma concentrations resulting from an intravenous administration of only a small amount of stable isotopically labeled phenytoin (DPH-d10) were determined to obtain information on the accurate clearance values under steady-state conditions attained with unlabeled phenytoin (DPH-d0). A time course of DPH-d10 concentrations was followed simultaneously with DPH-d0 during dosing intervals by GC-MS, with DPH-d5 as an internal standard. The present stable-isotope methodology offered advantages for the estimation of absolute bioavailability of the oral phenytoin dose in patients, while normal therapy was continued and not withdrawn.

Congenital deficiency of the fibula with ipsilateral iliac horn and absence of the kidney.

Congenital deficiency of the fibula is sometimes accompanied by femoral hypoplasia, genu valgum, patellar a/hypoplasia or dislocation, tibial bowing, foot deformity, and toe deficiency in the affected limb. 'Iliac horns' are bony projections extending posterolaterally from the ilium and considered to be pathognomonic of nail-patella syndrome. We report a 5-year-old Japanese girl with congenital complete deficiency of the left fibula, ipsilateral iliac horn and absence of the left kidney.

Changes of callus diameter during axial loading and after fixator removal in leg lengthening.

We retrospectively reviewed nine tibial lengthenings in seven achondroplastic patients. The callotasis method was used, and a unilateral type lengthener, either the Dynamic Axial Fixator (Orthofix, Italy; eight legs) or the High Functional Fixator (Matsumoto Co., Japan; one leg), was applied. The distracted length averaged 14.6 (range 10-18) cm. The minimum diameter of the callus was measured using a ruler on anteroposterior and lateral radiographs. The callus diameter ratio (%) was calculated as the callus diameter divided by the original diaphysis diameter. For periods during axial loading and after removal of the fixator in each patient, a single regression line was drawn on the callus diameter ratio data using the least squares method, and the diameter change rate (%/day) was evaluated by inclination of this line. The diameter change rates during axial loading were negative in six legs, but those after fixator removal were positive in all legs, and the latter were significantly greater than the former. The diameter change rates after fixator removal on the anteroposterior radiographs were negatively correlated with the callus diameter ratio at the time of fixator removal (r = 0.84, P = 0.0008). Simple axial loading may not be a sufficient mechanial environment for restoration of the physiological shape, and it is important to be aware that we cannot expect the callus diameter to increase by this means alone.

Stimulation of bone formation by recombinant fibroblast growth factor-2 in callotasis bone lengthening of rabbits.

Bone lengthening by callotasis is one of the most useful methods not only for the treatment of short extremities but also for extensive bone defects; however, the procedure takes a long time especially for the consolidation of the distracted callus. In this study, effects of a single local injection of recombinant human fibroblast growth factor-2 (FGF-2 or basic FGF) on callotasis bone lengthening were examined in rabbits. Ten days after the osteotomy at the middle of the tibia and the installment of an external fixator, the osteotomized site was distracted at a rate of 1.4 mm/day for 7 days, resulting in 9.8 mm lengthening. On the final day of distraction, 200 microg of FGF-2 in 150 microl of saline solution or vehicle alone was injected into the center of the distracted callus. Injection of FGF-2 increased bone formation at the distracted callus radiologically and histologically. A significant effect on bone mineral content (BMC) at the callus was observed as early as 2 weeks, and FGF-2 increased the BMC about twofold at 5 weeks after a normal remodeling process. We conclude that the callotasis method in combination with FGF-2 injection at the consolidation step could be clinically beneficial to shorten the bone lengthening period.

[Effect of loading time on the Vickers hardness number of dental gold alloys].

The Vickers hardness number (VHN) of pure metals (tin, aluminum, copper and gold) and dental gold alloys was measured using an automatically indenting and reading Vickers hardness tester (AKASHI.AUTOVICK) under a load of 1,000 gf with different loading times of 5 to 55 seconds. The samples of pure metals were cold rolled and softened by heating above recrystallization temperatures. The samples of ADAS No. 5 gold casting alloys were cold rolled, and then subjected to a softening heat treatment by water quenching (Types I, II, III and IV) or a hardening heat treatment by 450-250 degrees C/30 min oven cooling (Types III and IV). The results showed that there were no statistically significant differences between the measured values of VHN of a sample with different loading times as for the metals studied except pure tin which had a VHN of 5-6. The measured values of VHN by AUTOVICK were affected by the brightness of a light source for measurement, and they increased by 1.1 approximately as the voltage of the light source increased by 0.1 V. This was considered to be due to the protuberance caused by plastic flow of metals or slip lines on the surface around the indentation.

Stereo fluoroscopy-assisted percutaneous needle puncture of the vertebral body.

The purpose was to determine whether real-time three-dimensional imaging by stereo fluoroscope could alleviate the nuisance of moving the fluoroscope C-arm during needle biopsy of the spine. Fifteen lumbar vertebrae of four beagle dog cadavers were used in a simulation. We used a newly devised portable-type stereo fluoroscope, which alternatively exposes the X-ray from left and right X-ray tubes so that a surgeon can decode left and right images displayed alternately on a monitor by using polarizing glasses. A 2-mm-diameter Kirschner wire was inserted into the vertebral bodies by a posterolateral approach without moving the C-arm. An axial view of the roentgenogram of each vertebra found all 15 wires to be appropriately inserted. This would appear to be a time-saving feature.

The diameter of callus in leg lengthening: 28 tibial lengthenings in 14 patients with achondroplasia.

We investigated the relation between callus diameter during bone distraction and the occurrence of late fracture and deformity. We retrospectively reviewed 28 tibial lengthenings in 14 patients with achondroplasia. The minimal diameter of the lengthened zone was measured on radiographs, when the sliding mechanism of the lengthening device was released, and the callus diameter ratio in two planes (CDR; diameter of the callus/diameter of the tibia at the level of the osteotomy end) was calculated. The CDR correlated negatively with the distracted length. Late fracture or late angular deformity occurred in 6 of the 28 lengthenings. When the CDR was 85% or more in both planes, these complications did not occur, but when the CDR was 80% or less in either plane, they occurred in 6 of 20 bones. Careful attention should therefore be given not only to the continuity of the callus but also to its diameter.

Callus formation in femur and tibia during leg lengthening: 7 patients examined with DXA.

We examined the callus formation during leg lengthening in 7 achondroplastic patients who underwent 3 bilateral femoral and 4 bilateral tibial lengthenings. Bone mineral content and bone mineral density (BMD) in the lengthened callus space were evaluated every 1 or 2 weeks for 10 weeks after the start of distraction using dual energy X-ray absorptiometry. The mean rate of callus mineralization in femurs (0.64 g/wk) was higher than in tibias (0.22 g/wk). The mean BMD at 10 weeks after the start was 0.35 g/cm2 in the femur and 0.14 g/cm2 in the tibia. Different rates of callus formation in different kinds of long tubular bones have not been reported previously.

Influence of femoral lengthening on hip joint space in posttraumatic femoral shortening.

We performed femoral lengthening for post-traumatic femoral shortening in 14 patients (10 men). The mean age was 26 (17-33) years. The callotasis method was employed using an Orthofix or Hifixator monolateral external fixator. The average length gained was 6 (3-13) cm, equal to 16 (7-36)%. The mean narrowing ratio of the hip joint space during lengthening was 9 (0-26)% and the narrowing persisted at the final follow-up. Cases with narrowing greater than 5% had a longer time between the development of the shortening and the lengthening than the others (p = 0.03). Our findings indicate that femoral lengthening for posttraumatic femoral shortening should be done as early as possible to prevent the development of joint space narrowing during the lengthening procedure.

Local application of basic fibroblast growth factor into the bone increases bone mass at the applied site in rabbits.

The effect of basic fibroblast growth factor (bFGF) applied locally into the bone under physiological conditions was investigated. An aqueous solution containing 0 microgram (vehicle), 100 micrograms or 400 micrograms recombinant human bFGF was percutaneously applied through a needle into the right ilium in rabbit, and the ilia were harvested 4 weeks after the application. Compared with vehicle-treated animals, bone mineral density measured by dualenergy X-ray increased in the 400 micrograms bFGF group. The width of trabeculae in the bFGF-treated groups was greater than in the vehicle group. These results showed that bFGF applied locally into the bone under physiological conditions affected bone formation, and suggested that such an application might have potential for increasing bone.