Biomedical subjects

R Fujitani

Publications and source records attributed to R Fujitani.

6 recordsLinked to original sources

PubMed1988

Hematuria following blunt abdominal trauma. The utility of intravenous pyelography.

To clarify the indications for intravenous pyelography (IVP) and nephrotomography (NT) in the evaluation of patients with hematuria following blunt thoracoabdominal trauma, we performed a retrospective analysis of patients admitted during a one-year period who had undergone IVP and NT for suspected renal injury. One hundred thirty-four patients were reviewed, and the findings of IVP and NT correlated with the magnitude of hematuria on urinalysis, associated injuries, management, and outcome. Sixty-two (46%) of 134 patients had fewer than ten red blood cells per high-power field (RBCs/HPF) on urinalysis (group 1), 19 (14%) of 134 patients had 10 to 30 RBCs/HPF (group 2), and 53 (40%) of 134 patients had greater than 30 RBCs/HPF (group 3). Twenty-seven patients had renal injuries detected by IVP and NT, two in group 2 and 25 in group 3. We conclude that IVP and NT should be reserved for patients with greater than 30 RBCs/HPF on admission urinalysis.

Abdominal Injuries↗

PubMed1988

Histopathology of human laser thermal angioplasty recanalization.

Laserprobe thermal-assisted balloon, angioplasty (LTBA) has demonstrated promising initial clinical results in recanalizing stenotic or occluded superficial femoral and popliteal arteries. Over the past year we have obtained six specimens of laserprobe thermal (LT) and LTBA treated total occlusions (avg. length 12 cm) for histopathologic examination from patients who were treated for limb salvage. Three tissue specimens were obtained acutely, and one was obtained at 6, 8, and 13 days, respectively, after laser angioplasty at the time of revision for complications or failed procedures. Serial histologic sections of the treated LT segments demonstrated recanalization of atherosclerotic lesions to approximately 60-70% of the probe diameter. The LT channels were lined by a thin layer of carbonized or coagulated tissue and several layers of cell necrosis. The histology of the thermal injury was similar regardless of whether it was produced by the heated metal cap or by free argon laser energy. Stellate balloon angioplasty fractures were frequently filled with thrombus. Analysis of these human LT and LTBA specimens revealed that the thermal device produces a confined injury through the path of least resistance. Balloon dilatation produces fragmented cracks in the vessel wall, which appear to be more thrombogenic than the carbonized LT surface. With improved guidance methods, LTBA shows potential for continuing development.

Aged↗

PubMed1988

CO2 and argon laser vascular welding: acute histologic and thermodynamic comparison.

CO2 and argon lasers have been used successfully for vascular welding in both experimental and clinical settings. This study compared the thermodynamics during CO2 and argon laser welding of 1-cm longitudinal arteriotomies in a canine model. Continuous recordings using an AGA 782 digital thermographic system with spatial and thermal resolution of +/-0.2 mm and +/-0.2 degree C, respectively, were analyzed. A HGM argon laser using a 300-microns optic fiber held at 1 cm from the vessel edges (spot diameter = 2.8 mm) with concomitant room temperature saline irrigation (1 drop/sec) was used for argon welds. Total exposure time was 150 sec/cm. CO2 welds were performed with a Sharplan CO2 laser (spot diameter = 0.22 mm) with no irrigation for total exposure time of 10 sec/cm. Thermodynamic results and laser parameters are summarized as follows: Argon-n = 20; power = 500 mW; energy fluence = 1,400 J/cm2; Tmax = 48.8 degrees C; T mean +/- S.D. = 45.1 +/- 2.7 degrees C; CO2-n = 20; power = 150 mW; energy fluence = 3,000 J/cm2; Tmax 84.0 degrees C; T mean +/- S.D. = 60.7 +/- 9.8 degrees C. There was a significant difference (P less than .05) in thermal measurements between successful CO2 and argon vascular welds. Temperature rise during the argon welds was limited by saline irrigation. In contrast, during CO2 laser welding, the temperature rose quickly to its maximum and was maintained at a relatively high level as the laser progressed (0.1 cm/sec) along the anastomosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1987

Valvulotomy in in situ vein bypasses performed by angioscope-assisted laser probe.

The objective of this study was to evaluate the use of an angioscope-assisted laser hot-tip probe for performing valvulotomies in in situ nonreversed canine veins used for arterial bypasses. In Group 1, 9 valvulotomies were performed in 7 bypass veins with a 2-mm probe activated by 12 W power, resulting in 4 vein perforations, 1 vein thrombosis, and 4 in situ grafts patent at removal after 2-28 days. In Group 2, 10 valvulotomies in 9 bypass veins were performed with a 1.5-mm probe at 14 W with no vein perforations, 3 vein thromboses, and 6 in situ grafts patent at removal after an interval of 1 to 6 weeks. We conclude that valvulotomy within in situ vein bypasses can be successfully performed using a 1.5-mm laser hot-tip probe at 14 W power, with patency of the grafts demonstrated at 6 weeks. Angioscope-assisted laser valvulotomy using a laser probe may significantly reduce the length of incisions and the time required for in situ vein bypasses and improve the technical accuracy of the procedure.

Animals↗

PubMed1987

Laser vascular welding--how does it work?

This study evaluated the histology and electron microscopy of four samples of 2 cm long venotomies and artery-vein anastomoses formed in canine femoral arteries and veins using the argon laser (0.5 W power, 1 800 J/cm2, 4 min exposure/1 cm length of anastomosis). Welds were continuously irrigated with saline during the procedure to limit maximal temperatures to 44.2 +/- 1.6 degrees C (mean +/- SD), and the specimens were removed immediately following fusion and preserved for examination. Histologic and electron microscopic examination of different areas of the welds revealed various mechanisms of fusion including a) apposition of denatured collagen and elastin in the media and adventitia; b) bonding of vein medial collagen and elastin to the internal elastic membrane of the artery; and c) fusion consisting of a coagulum of platelets and fibrin depending on the alignment and apposition of the vessel edges. This study demonstrates that vascular tissue fusion by the argon laser occurs by various mechanisms. Future experiments should delineate which types of seal produce the optimal strength at the time of fusion, and enhance long-term healing.

Animals↗

PubMed1987

Argon laser-welded arteriovenous anastomoses.

This study compared the healing of laser-welded and sutured canine femoral arteriovenous anastomoses. Arteriovenous fistulas 2 cm in length were created bilaterally in the femoral vessels of 10 dogs and were studied at 1 (n = 2), 2 (n = 2), 4 (n = 3), and 8 (n = 3) weeks. In each animal, one anastomosis (control) was closed with running 6-0 polypropylene sutures, and the contralateral anastomosis (experimental) was sealed with an argon laser (0.5 watt, 4 minutes of exposure, 1830 J/cm2/1 cm length of anastomosis). At removal all experimental anastomoses were patent without hematomas, aneurysms, or luminal narrowing. Histologic examination at 4 weeks revealed that laser-welded anastomoses had less inflammatory response and almost normal collagen and elastin reorientation. At 8 weeks sutured anastomoses had significant intimal hyperplasia whereas laser repairs had normal luminal architecture. Tensile strength and collagen production, measured by the synthesis of hydroxyproline and the steady-state levels of type I and type III procollagen messenger ribonucleic acids, at the anastomoses and in adjacent vein and artery specimens were similar in sutured and laser-welded repairs at 2, 4, and 8 weeks. We conclude that argon laser welding of anastomoses is an acceptable alternative to suture techniques, with the advantage of improved healing without foreign body response and possible diminished intimal hyperplasia at the anastomotic line.

Animals↗