Biomedical subjects
H Yuasa
Publications and source records attributed to H Yuasa.
Temporary cardiac arrest for the coronary arteriography and the thoracic aortography.
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Sonographic diagnosis of small intestinal anisakiasis.
PURPOSE: We studied the utility of sonography in the early diagnosis of anisakiasis of the small intestine. METHODS: The imaging findings and clinical data of 12 patients with proven small intestinal anisakiasis were retrospectively reviewed. RESULTS: Dominant sonographic findings were ascites, small bowel dilatation, and focal edema of Kerckring's folds. CONCLUSIONS: Patients who have acute abdomen after recent ingestion of seafood and in whom ascites, small bowel dilatation, and focal edema of Kerckring's folds are seen by sonography should be suspected of having small intestinal anisakiasis and should be treated conservatively without laparotomy.
Effect of drug-vinyl copolymer delivery composites on the rat prostate.
A radiation polymerized drug-vinyl copolymer delivery composite (0.8 mm in diameter, 3 mm long) was inserted into the right-lobe ventral prostate (I), into the right testis (II), and subcutaneously (III) into the back of male Wistar rats. The implantation was carried out over a period of 12 weeks maximum. From the relationship between the site of surgical insertion of the implant and the physiologic response (as measured by the decrease in the weight of the prostatic organs, e.g., ventral prostates, dorsolateral prostates, and seminal vesicles), it was found that in an AA560-containing composite (36 micrograms daily), the physiologic response is increased in order of (III) greater than (II) greater than (I). The same tendency was observed in the Estracyt-containing composite system (15 micrograms daily). The difference in the physiologic response owing to the site of surgical insertion of the implant was not observed in an E2-17 beta-containing composite (6 micrograms daily), although this composite showed the strongest physiologic response. No physiologic response in rats with CMA-containing composite (28 micrograms daily) was noted.
Relief of mesenteric ischemia by Z-stent placement into the superior mesenteric artery compressed by the false lumen of an aortic dissection.
In a 58-year-old man acute aortic dissection compromised the origin of the superior mesenteric artery (SMA), resulting in mesenteric ischemia. After failed balloon angioplasty a Gianturco Z-stent was placed. The stenosis improved immediately, followed by resolution of the clinical signs of mesenteric ischemia. SMA flow was well preserved 1 year after stenting.
Treatment of acute aortic dissections with expandable metallic stents: experimental study.
PURPOSE: This experimental study was designed to evaluate the effectiveness of metallic stents for the treatment of acute aortic dissection. MATERIALS AND METHODS: Thoracic aortic dissections were created in 14 mongrel dogs. Aortography performed immediately after creation of dissections showed two types of aortic dissections: rapid flow in the false lumen (group 1) and slow flow in the false lumen (group 2). Each group consisted of seven dogs. For each group, expandable metallic Gianturco stents were placed in five dogs and two dogs were used as controls. RESULTS: A week later, false lumina were patent in all dogs in group 1 and thrombosed in all dogs in group 2. In group 1, the mean diameter of the true lumina was considerably enlarged from 5.9 mm +/- 1.6 to 9.9 mm +/- 2.8 and that of the false lumina significantly diminished from 9.1 mm +/- 1.3 to 5.2 mm +/- 2.3 (P < .05) after stent placement. In group 2, the true lumina were significantly dilated (5.2 mm +/- 2.3 vs 12.3 mm +/- 3.1, P < .05) and the false lumina disappeared completely (9.2 mm +/- 3.3 vs 0.0 mm, P < .01). Furthermore, the two control dogs in group 2 died of visceral ischemia due to the compression of the true lumen by the thrombosed false lumina, but the dogs with stents showed no symptoms of the visceral ischemia. CONCLUSION: Expandable metallic stents are not effective in obliterating the false lumen in acute aortic dissection but may be useful in maintaining the blood flow in the true lumen and avoiding visceral ischemia.
Treatment of aortic dissections with a percutaneous intravascular endoprosthesis: comparison of covered and bare stents.
PURPOSE: The authors developed a percutaneous endoprosthesis for treatment of aortic dissections. The device is a Gianturco stent wrapped with Dacron or nylon mesh. Effectiveness of the covered stent versus a bare stent was compared in the treatment of acute aortic dissection. MATERIALS AND METHODS: Experimental aortic dissections were created in 10 mongrel dogs. Occlusion of intimal tears was attempted with covered stents in five dogs (group 1) and with bare stents in the remaining five dogs (group 2). RESULTS: In group 1, entry tears were obliterated within 1 day (n = 3) or 1 week (n = 2) after stent placement and false lumina were thrombosed within 1 week (n = 3) or 1 month (n = 2). In group 2, entry tears and false lumina remained patent. Histologic specimens showed that the covered stents were entirely covered with smooth neointima. CONCLUSIONS: This endoprosthesis offers an alternative to surgical treatment for dissections of the descending aorta.
Transport functions of riboflavin carriers in the rat small intestine and colon: site difference and effects of tricyclic-type drugs.
The present study was aimed at kinetically characterizing the newly found carrier-mediated riboflavin transport system in the rat colon, comparing it with that in the small intestine, and also probing the potential roles of these transport systems in intestinal drug absorption. Riboflavin transport, evaluated by measuring the initial uptake into everted intestinal tissue sacs, was saturable with a Michaelis constant (Km) of 0.13 microM and a maximum transport rate (Jmax) of 0.74 pmol/min/100 mg wet tissue weight (wtw) in the colon. Both the Km and the Jmax were smaller than those (0.57 microM and 4.26 pmol/min/100 mg wtw, respectively) in the small intestine, suggesting that the transport system in the colon has a higher affinity to substrates and a smaller transport capacity than its counterpart in the small intestine. The carrier-mediated riboflavin transport in the colon, similarly to that in the small intestine, was Na+-dependent and inhibited by lumiflavin, a riboflavin analogue with an isoalloxazine ring, but not by D-ribose, which forms the side-chain attached to the isoalloxazine ring in riboflavin. To further clarify the substrate specificities of the transport systems, we examined the effects of several drugs with a tricyclic structure similar to isoalloxazine ring on riboflavin transport. Chlorpromazine, a phenothiazine derivative, was found to inhibit riboflavin transport in both the small intestine and the colon. Methylene blue also was found to be a potent inhibitor in both sites. These results suggest that some tricyclic-type drugs could interfere with intestinal riboflavin absorption by specific carrier-mediated transport systems. These transport systems may play roles in the absorption of tricyclic-type drugs.
The role of the protein C-thrombomodulin system in physiologic anticoagulation during cardiopulmonary bypass.
Changes in the protein C-thrombomodulin (PC-TM) system in relation to other coagulofibrinolytic parameters were examined in 25 patients undergoing open heart surgery. Although all patients were given heparin, a decrease in antithrombin III (ATIII) and progressive increase in thrombin-ATIII complex (TAT) and fibrinopeptide A (FPA) levels were noted during cardiopulmonary bypass, which indicated that heparinization did not completely inhibit the formation of thrombin and its function. C1-inactivator (INA) resistant fibrinolytic activity increased markedly during CPB, in parallel with the change of tissue plasminogen activator antigen (t-PA;Ag), which indicates that fibrinolytic activity during CPB is mainly of extrinsic origin caused by t-PA. Protein C antigen (PC;Ag), protein S antigen (PS;Ag), and thrombomodulin antigen (TM;Ag) were all decreased significantly during CPB. This is considered to reflect the activation and consumption of the PC-TM system in response to generated thrombin. Furthermore, enhancement of the extrinsic fibrinolytic system is easily explained by the action of activated PC, which counteracts plasminogen activator inhibitor (PAI-1), to cause enhancement of t-PA activity.
Effect of ultrafiltration on priming solution with preserved blood for extracorporeal circulation in infants.
In pediatric cardiac surgery, the initial priming solutions of the extracorporeal circulation include preserved blood. In an effort to eliminate unfavorable effects of preserved blood on the circulation, the authors introduced the preserved blood to ultrafiltration (UF). Seventeen infants with congenital heart defects were included in this study. UF was performed with a polysulfone ultrafiltrator before extracorporeal circulation. The 1600 ml of fluid, consisting of saline, 5% glucose, and maltose, were added to 400 ml of preserved blood, and the same amount of fluid was removed by UF. The concentrations of potassium, NH3, and bradykinin in the priming blood decreased significantly after UF. In the UF group, water balance during extracorporeal circulation and max. Creatinine-phosphokinase levels after surgery were better than controls. These data suggest that UF is able to remove some substances and result in reduction of an unfavorable effect on the circulation.
Effects of high-dose vitamin C administration on postburn microvascular fluid and protein flux.
The effects of vitamin C treatment (14 mg/kg/hr) on burn injury were evaluated in the hind paws of 12 mongrel dogs. A lymph duct above one hind paw of each dog was cannulated. Hourly lymph flow rates (QL) and plasma and lymph total protein concentrations were measured before the burn injury and for 6 hours after the burn injury. Data from 24 paws were divided into four groups: nonburn without treatment, nonburn with treatment, burn without treatment, and burn with treatment. The nonburn groups showed no significant differences in QL or in total protein flux. In the burn groups the postburn hourly QL increased by sevenfold in the nontreatment group and only by threefold in the treatment group, whereas the postburn hourly total protein flux increased by fifteenfold and fivefold, respectively. We conclude that administration of high-dose vitamin C reduces early postburn microvascular leakage of fluid and protein.
The effects of high-dose vitamin C therapy on postburn lipid peroxidation.
The effects of vitamin C treatment (14 mg/kg/hr) on postburn lipid peroxidation were evaluated in 12 dogs. A lymph duct above the ankle was cannulated bilaterally. Hourly lymph flow rates, plasma and lymph total protein concentrations, and plasma and lymph malondialdehyde concentrations were measured before the burn injury and for 24 hours after the burn injury. Four groups were employed: nonburn without treatment, nonburn with vitamin C treatment, burn without treatment, and burn with vitamin C treatment. The nonburn groups showed no significant differences in lymph flow rates, total protein flux, or lymph malondialdehyde level. In the burn groups the postburn hourly lymph flow rate increased by 850% without treatment and by 500% with vitamin C treatment, whereas the postburn hourly total protein flux increased by fiftyfold and twentyfold, respectively. There was a significant reduction in the postburn lymph malondialdehyde level in the group treated with vitamin C as compared with the nontreatment group. We conclude that high-dose vitamin C administration diminishes early postburn lipid peroxidation and reduces microvascular leakage of fluid and protein.
Brain malformations caused by retroviral vector-mediated gene transfer of hippocampal cholinergic neurostimulating peptide precursor protein into the CNS via embryonic mice ventricles.
Hippocampal cholinergic neurostimulating peptide precursor protein (HCNP-pp) is a unique multifunctional protein, being not only the precursor of HCNP, which promotes the phenotype development of septo-hippocampal cholinergic neurons, but also the binding protein of phosphatidylethanolamine, ATP, Raf-1 kinase (known as "Raf-1 kinase inhibitory factor" in peripheral organs), and serine protease. We obtained a high-titer retroviral vector harboring HCNP-pp cDNA by the use of a modified packaging cell line and centrifugation, and by injecting it into embryonic mouse ventricles, we investigated the function of its gene product within the central nervous system (CNS). We found that efficient transduction into hippocampal pyramidal neurons can be achieved by injecting the vector into embryonic brain ventricles on embryonic day 14 (E14). Three days after receiving the intraventricular injection of the high-titer HCNP-pp retrovirus vector on E14, the tissues around the ventricles showed an overexpression of HCNP-pp. This was accompanied by a reduced amount of activated MEK and Erk (as analyzed by histochemical and Western blot methods), suggesting that HCNP-pp also regulates the MAP-kinase cascade within the CNS. Surprisingly, mouse brains that received the HCNP-pp retroviral vector showed massive malformation of the hippocampus and cerebellum when examined 30 days after birth. This shows that strictly regulated HCNP-pp gene expression is necessary for the normal development of the mouse brain, and that the moderate overexpression achieved by retroviral vector-mediated gene transfer is sufficient to cause severe abnormality of entire brain structures.
Histologic changes in donor bronchi may explain the reduced mucosal blood flow seen during acute lung allograft rejection.
We assessed the histologic changes in donor and recipient bronchi from 15 dogs that had received a lung transplant and related these changes to the severity of acute rejection seen in the parenchyma of these same lungs. Minimal rejection was associated with no abnormal change in either the donor or the recipient bronchi. In mild lung rejection, mononuclear cell cuffings were seen around bronchial arteries in donor bronchial adventitia, although few mononuclear cell infiltrates were seen in the submucosa. Moderate lung rejection was associated with more prominent mononuclear cell cuffings in the donor bronchial adventitia and mucosal infiltrates of mononuclear cells in the membranous portion. In cases of severe lung rejection, the mononuclear cell infiltrates were also apparent in the cartilaginous portion of the donor bronchial mucosa. Moreover, submucosal edema and detachment of bronchial epithelium were seen. These histologic changes were not observed in the recipient bronchi during acute rejection, nor were they seen in the donor and the recipient bronchi during lung infection without rejection. They might, therefore, reflect acute rejection in the donor bronchus. These results might provide the histologic support for our previous observation of decreased bronchial mucosal blood flow measured by the laser Doppler flowmeter in relation with the extent of acute lung rejection.
Administration of haptoglobin during cardiopulmonary bypass surgery.
A study was undertaken to evaluate hemolysis and subsequent renal damage in 14 patients undergoing cardiopulmonary bypass (CPB) surgery. In all patients, free haptoglobin disappeared completely 30 to 90 minutes into CPB, while free hemoglobin (Hb) levels increased progressively. The NAG index and alpha 1M index also increased progressively, indicating renal tubular injury due to hemolysis (Study 1). An additional 20 patients were monitored intraoperatively for plasma free Hb levels by a newly developed colorimetric method using a haptoglobin coated strip. Free Hb levels during CPB exceeded 30 mg/dl in 14 patients, who were immediately given haptoglobin. This treatment eliminated plasma free Hb within 30 minutes, and effectively prevented hemoglobinuria. Haptoglobin treatment brought significant decreases in the NAG index and alpha 1M index, suggesting a protective effect on renal function (Study 2).
Nafamostat mesilate administration during cardiopulmonary bypass decreases postoperative bleeding after cardiac surgery.
The hemostatic effect of nafamostat mesilate (FUT-175) was evaluated in patients undergoing cardiopulmonary bypass (CPB) surgery. Thirty patients undergoing aortocoronary bypass grafting were divided into two groups. In the control group, anticoagulation was achieved with an initial dose of heparin (3 mg/kg). In the FUT-175-treated group, in addition to the ordinary treatment with heparin, FUT-175 was infused continuously into the circuit throughout the procedure at a rate of 100 mg/hr. Thrombin-antithrombin III complex (TAT), fibrinopeptide A (FPA), and fibrin degradation products (FDP-D) dimer increased in both groups as CPB proceeded. In the FUT-175-treated group, these parameters remained lower and decreased more rapidly after the end of CPB. Alpha 2 plasmin inhibitor/plasmin complex (PIC) increased progressively during CPB in the control group; no such significant increases were seen in the FUT-175-treated group. Postoperative blood loss was significantly lower in the FUT-175-treated group than in the control group. It was concluded that FUT-175 reduces postoperative blood loss by inhibiting both coagulation and fibrinolysis during CPB.
Significance of bronchial mucosal blood flow for the monitoring of acute rejection in lung transplantation.
Bronchial mucosal blood flow (BMBF) was measured with a laser-Doppler flowmeter in a canine model (n = 20), and the measurement was evaluated to see if it was a useful method for diagnosing allografted lung rejection. The ratio of the value of BMBF at the level of the donor second carina against that at the level of carina (the L/C ratio, an index of BMBF of donor bronchus) decreased in accordance with the extent of lung rejection, and it increased and entered the normal range with the reversal of lung rejection. Compared with the L/C ratio and the rejection grade by histologic changes in open-lung biopsy, the L/C ratio at grade 0 (latent phase) was 0.91 +/- 0.07; at grade Ia (early vascular phase), 0.86 +/- 0.05; at grade Ib (late vascular phase), 0.68 +/- 0.10; at grade II (early alveolar phase), 0.60 +/- 0.14; and at grade III (late alveolar phase), 0.50 +/- 0.15. A significant difference was noted between grades Ia and Ib (p less than 0.01) and between grades Ib and III (p less than 0.01). The sensitivity and the specificity in the detection of early rejection before grade Ib were 96% and 92%, with only one false-negative and two false-positives resulting from 51 measurements of BMBF. In three cases of serious lung infections, the L/C ratio did not fall, and the rejection could be distinguished from infection. These results suggest that measurement of the BMBF is useful for detecting the early rejection of transplanted lungs.
New diagnostic method for pulmonary allograft rejection by measurement of bronchial mucosal blood flow.
We investigated the relationship between the rejection of lung allografts and the bronchial mucosal blood flow with a laser flowmeter. Nineteen mongrel dogs underwent left lung allotransplantation and were given daily oral immunosuppressive therapy with azathioprine and cyclosporine. The bronchial mucosal blood flow at the carina and the bifurcation of left upper and lower bronchi were measured on days 14, 21, and 28 after left lung transplantation. The bronchial mucosal blood flow of the transplanted lungs was expressed as the ratio of bronchial mucosal blood flow at the bifurcation of left upper and lower bronchi to the bronchial mucosal blood flow at the carina (L/C ratio) instead of the absolute value because bronchial mucosal blood flow was affected by the depth of anesthesia of the dogs. We classified the histologic appearance of the transplanted lung tissue into one of five grades: 0, 1a, 1b, 2, and 3. No rejection was in grade 0, and as the rejection process progressed the higher grades were used in order. The mean L/C ratios for grades 0, 1a, 1b, 2, and 3 were 0.95 +/- 0.03, 0.82 +/- 0.05, 0.68 +/- 0.04, 0.58 +/- 0.07, and 0.30 +/- 0.07, respectively. Thus the L/C ratio decreased as the rejection process progressed. The histologic changes of the donor main bronchus in each rejection grade were investigated. Mononuclear cell infiltration and edema around the small vessels was seen in early rejection. These same histologic changes appeared in muscular arteries as rejection progressed, and the damage to the small vessels and muscular arteries was more severe in late rejection.(ABSTRACT TRUNCATED AT 250 WORDS)