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Biomedical subjects

J Utoh

Publications and source records attributed to J Utoh.

At least 55 records · Page 3Linked to original sources
PubMed1996

Inflammatory reactions after vascular prosthesis implantation: a comparison of gelatin-sealed and unsealed Dacron prostheses.

Despite widespread use of the gelatin-sealed knitted Dacron prosthesis (GDP) in clinical practice owing to its zero porosity, the biological impacts of this graft are still controversial. We conducted a randomized controlled study on 50 patients undergoing abdominal aortic aneurysm repair to evaluate the inflammatory reaction to GDP (n = 25) and unsealed knitted Dacron prostheses (UDP, n = 25). There were no significant differences in the mean age, size of the aneurysm, operative time, blood loss, or transfusion requirements between the GDP and UDP groups. During the first 7 postoperative days (PODs), slight fever and leukocytosis were noticed in both groups. Significant differences in maximum body temperature, leukocyte count, and plasma C-reactive protein concentration were observed between the GDP and UDP groups on POD 14:37.2 +/- 0.5 degrees C vs 36.9 +/- 0.3 degrees C (P = 0.019), 8,151 +/- 1,788/microliters vs 6,914 +/- 1,501/microliters (P = 0.015), and 32.6 +/- 27.5 mg/l vs 19.0 +/- 15.8 mg/l (P = 0.048), respectively. By POD 21, however, there were no detectable differences in these variables. Thus, we concluded that GDP caused an inflammatory reaction in the 2nd week after implantation, but ultimately there were no significant differences from UDP by the 3rd week.

Aged↗
PubMed1996

Oxygen metabolism after cardiopulmonary bypass.

We hypothesized that the relationship between oxygen delivery (DO2) and oxygen consumption (VO2) in patients undergoing cardiopulmonary bypass (CPB) may differ from the normal physiologic state because of oxygen debts acquired during CPB. Blood gas analysis and hemodynamic parameters were repeatedly measured for determination of DO2 and VO2 in 40 patients undergoing CPB every 8 hours during the first 48 hours postoperatively. Twenty patients of acute myocardial infarction (AMI) also were studied in the same protocol as controls. In the CPB group, a regression analysis showed that VO2 was significantly dependent on DO2, even within the physiologic range of DO2 (>500 ml/min/m2); VO2=121+0.0844 DO2 (R=0.25, p=0.023). However, such supply-dependent oxygen consumption was not observed in the AMI patients. Perioperative parameters which had a significant relationship with oxygen extraction rate (VO2/DO2 x 100) were Hb concentration, cardiac index, systemic vascular resistance, age of the patients, duration of CPB, SaO2 and SvO2. These results suggest that patients undergoing CPB need a much higher oxygen supply to recover from the oxygen debt during open heart surgery.

Cardiopulmonary Bypass↗
PubMed1996

Dilation of gelatin-sealed knitted dacron prosthesis.

OBJECTIVE: Postoperative dilation of gelatin-sealed knitted dacron prostheses (Gelseal, Vascutek, Scotland UK) was studied. EXPERIMENTAL DESIGN: Prospective study. SETTING: Institutional clinical research. MATERIALS AND METHODS: Ten patients who underwent aortic repair for abdominal aortic aneurysm (AAA) with the Gelseal graft were studied (Group A). Prior to and immediately following the implantation, the diameter of Gelseal was measured with slide calipers. The external diameter was examined by CT scan 4 weeks following the surgery. Another 10 patients, who had undergone AAA repair with the Gelseal graft more than 2 years earlier (Group B), also were examined by CT scan. Early and late dilation of Gelseal was estimated and the data from the two groups were compared. MEASURES: In Group A, the preimplantation external diameter was 22.6 +/- 2.3 mm while the mean package size (PS) used was 18.7 +/- 2.1 mm prior to implantation. Just after the implantation, the external diameter changed to 22.7 +/- 2.4 mm. Four weeks later, it averaged 24.0 +/- 2.2 mm. In Group B, the PS averaged 19.2 +/- 2.0 mm, while the external diameter measured by CT scan averaged 27.8 +/- 3.4 mm at a mean of 31.3 months following the surgery. RESULTS: Prior to implantation, the external diameter was 1.21 times that of the PS. Following implantation, it was 1.21 times (immediately after), 1.28 times (4 weeks later), and 1.45 times (31.3 months later) of the PS. CONCLUSIONS: At an average of 31.3 months following implantation, the external diameter was 45% larger than the PS. Considering that the external diameter was 21% larger than the PS even prior to implantation, the actual dilation rate is estimated as 24% of the PS in the late postoperative period.

Aged↗
PubMed1996

[Veno-arterial bypass and intraaortic balloon pumping for profound right heart failure--a case report of perioperative right heart infarction].

A combination of veno-arterial bypass (VAB) and intraaortic balloon pumping (IABP) was applied to a 54-year-old male patient whose right heart function was severely damaged immediately following aortic valve replacement. A diagnosis of perioperative myocardial infarction was made with findings of severe hypokinesis of the right heart, new Q wave with ST elevation, and increased cardiac escaping enzyme. The VAB was maintained wih a pump flow rate of 2.0-2.5 L/min. The system was exchanged to the second one 42 hours after the surgery. According to repeated on/off testing, the VAB was successfully weaned on the 5th postoperative day followed by weaning IABP on the 6th postoperative day. This case report shows a recovery from isolated right heart failure by an immediate switching from a cardiopulmonary bypass to VAB and IABP.

Aortic Valve↗
PubMed1995

[Oxygen economy in patients after open heart surgery--effects of cardiopulmonary bypass on oxygen metabolism].

The relationship between oxygen delivery (DO2) and oxygen consumption (VO2) was studied in thirty patients who underwent open heart surgery. Delivery dependent consumption was observed for the first 48 hours after the surgery even DO2 was in a physiological range (> 300 ml/min/m2). VO2 decreased in proportion to a decrease in DO2 (VO2 = 0.132 x DO2 + 87.9, R = 0.616, p < 0.001). Oxygen extraction rate (ER = VO2/DO2) increased also in proportion to a decrease in DO2 (ER = -0.385 x DO2 + 51.8, R = -0.722, p < 0.001). These results suggest that tissue oxygen demand in the early postoperative period is higher than physiological conditions. Factors which directly influenced ER were cardiac index (CI) and hemoglobin (Hb) as expressed in the following formulas; ER = -6.05 x CI + 51.6 (R = -0.592, p < 0.001), ER = -2.02 x Hb + 56.7 (R = -0.414, p < 0.001). This indicates that hypoperfusion and anemia deteriorate oxygen metabolism in the early postoperative period. As a monitor of oxygen demand, oxygen saturation of mixed venous blood (SvO2) was an useful parameter to indicate the ER (ER = -0.872 x SvO2 + 91.9, R = -0.969, p < 0.001).

Adult↗
PubMed1993

Quantification of the edge effect in calcified bioprosthetic tissues.

In bioprosthetic tissue samples that had been implanted in the subcutaneous space of rats, and recurring pattern of calcification was observed. In this pattern, which we call the edge effect, the interior of the tissue is calcified and is surrounded and separated from the subcutaneous fluid by a zone that is free from calcification. The edge effect has been qualitatively described in the literature for subcutaneous implants and for valve leaflets, and it may be related to the mechanism of calcification for these materials. The thickness of the calcification free outer layer was quantified for glutaraldehyde treated bovine pericardium, glycerol treated bovine pericardium, glutaraldehyde treated human dura mater, and glycerol treated human dura mater. The edge effect values were found to be unique and consistent for each material type, and they were inversely related to the shrinkage temperatures and the calcium contents of the materials. It was determined that the chemical treatment was more important than the tissue type in determining the edge effect value.

Abdomen↗
PubMed1993

Chronic in vivo function of a new ventricular assist device: the extracorporeal pulsatile assist device (EPAD).

An extracorporeal pulsatile assist device (EPAD) is a valveless, single-chambered, pneumatically-actuated blood pump composed of a graft conduit, connecting ring, bladder, and blowmolded housing. This allows a simple and quick surgical procedure and is easily actuated with a conventional intraaortic balloon pumping console if desired. To evaluate in vivo pump functions, the EPAD was tested in calves as a left ventricular assist device for 6-24 days. The EPAD was well synchronized to the natural heart beat up to 130 bpm in the counterpulsation mode with mild systemic heparinization (active clotting time: 200-250 seconds). Heart rate, coronary flow and cardiac output were not significantly changed by on-off testing. However, the pump showed promising diastolic augmentation (10.8% increase in the diastolic pressure time index) in these chronic animal experiments.

Animals↗
PubMed1992

Damage to erythrocytes from long-term heat stress.

1. Erythrocytes are known to haemolyse in vitro at 48-50 degrees C. We hypothesized that erythrocytes might be damaged at much lower temperatures if they are incubated for prolonged periods. Erythrocytes from healthy human donors (n = 7) were incubated at 37, 40, 42, 44, 46 or 48 degrees C for 4-48 h. The haemolytic percentage and osmotic fragility were then measured by a modification of the method of Parpart et al. 2. Significant haemolysis and increased fragility were not observed at any temperatures after incubation for 4 h. However, the haemolytic percentage increased after incubation for 24 h at 44 degrees C (9.1 +/- 4.9%, P less than 0.01), 46 degrees C (52.4 +/- 14.1%, P less than 0.01) and 48 degrees C (98.0 +/- 2.6%, P less than 0.01) and after incubation for 48 h at 42 degrees C (9.8 +/- 4.5%, P less than 0.01) when compared with the values before heating (1.1 +/- 0.9%). The osmotic fragility also increased after incubation for 24 h at and above 42 degrees C. 3. Although heat-induced haemolysis and an increase in fragility have not been known to occur below 48 degrees C, these were quite apparent after incubation for 24-48 h at only 42 degrees C. This suggests that with regard to thermal effects, it is important to consider not only the temperature but also the duration of heating.

Cells, Cultured↗
PubMed1992

Effects of temperature on phagocytosis of human and calf polymorphonuclear leukocytes.

The in vitro effect of temperature on the phagocytic function of human and calf polymorphonuclear leukocytes (PMN) was studied. To observe the PMN phagocytic function (PPF) at various temperatures, PMN from healthy human and calf donors were incubated with serum-opsonized fluorescent latex particles (diameter 1.66 microns) at 25, 37, 40, 42, 44, or 46 degrees C for 1 h and then observed for their phagocytic activity by fluorescent microscopy. At 25, 40, and 42 degrees C, human PPF was not significantly different from that at 37 degrees C (87%, 89%, and 80% vs. 93%). At 44 degrees C, PPF was noticeably depressed (19%, p < 0.05) when compared to that at 37 degrees C. Next, to determine the critical temperature and duration of exposure that would irreversibly damage PPF, PMN were preincubated at 42, 44, or 46 degrees C for 5-30 min before being subjected to a standard phagocytosis assay at 37 degrees C. The human PPF was significantly depressed after 30 min at 44 degrees C (33%, p < 0.05) or 10 min at 46 degrees C (30%, p < 0.05). In conclusion, neither human nor calf PPF was significantly altered at and below 42 degrees C. In contrast, the PPF was irreversibly and time-dependently damaged when incubated at and above 44 degrees C.

Animals↗
PubMed1989

Neutrophil producing capacity of 5-lipoxygenase metabolites of arachidonic acid after major surgery.

It is well known that patients who undergo surgical operations have a high risk of infection and sepsis. One explanation for this high risk may be a depression of neutrophil functions at the postoperative period. In the present study, the effects of surgical stresses on neutrophil functions were studied in ten patients who underwent general anesthesia and major surgery. The neutrophil functions especially focused on were the producing capacities of 5-lipoxygenase metabolites of arachidonic acid such as Leukotriene B4 (LTB4), LTC4, LTD4, 6-trans-LTB4, and w-oxidation products of LTB4. Neutrophils were stimulated with calcium-ionophore A23187 (2x10(-5) M) in the presence of arachidonic acid (5x10(-5) M) for 5 minutes at 37 degrees C. The arachidonic acid metabolites were extracted by methanol. After centrifugation, the supernatant of the mixture was concentrated and applied to a C-18 column on reversed phase high performance liquid chromatography (RP-HPLC) system, monitoring the absorbance at 280 nm. In all cases, the LTB4 production significantly increased postoperatively with an increment of 6-trans-LTB4 and w-oxidation products of LTB4. The LTC4 production, by contrast, significantly decreased postoperatively. LTD4 production was observed at neither pre nor postoperative periods. The total amount of LTA4 metabolites at the postoperative period, including LTB4, LTC4, and 6-trans-LTB4, increased 1.2 times compared with that at preoperative period. This indicates the possibility of the alteration of the neutrophil metabolism in 5-lipoxygenase cascade, the increment of LTA4 generation and the change of LTA4 metabolism from LTC4 synthesis to LTB4 generating pathway.

Abdominal Neoplasms↗
PubMed1989

Complement activation and neutrophil dysfunction in burned patients with sepsis--a study of two cases.

The changes in complement components and neutrophil functions were investigated in two cases of flame burn patients who died of multiple organ failure following septic shock. In the period of bacteremia, complement activation was observed in the plasma of both patients, using an immunoblotting method demonstrating C3a-related antigens. Coincidently, reduced neutrophil function and a decrease in the superoxide and leukotriene producing capacity, were also observed. An in vitro study showed that the capacity to produce superoxide and leukotriene became reduced in normal neutrophils after exposure to complement activated serum. These observations suggested that complement activation, probably brought about by massive bacterial infection, induced the impairment of neutrophil functions and resulted in a further breakdown of the host defence system, thereby leading to sepsis.

Adult↗
PubMed1989

[Benefits and limitation of extracorporeal circulation with autologous blood using low priming membrane oxygenator].

The high incidence of hepatitis following cardiopulmonary bypass has stimulated attempts to develop a technique of perfusion without homologous blood. Between October, 1987 and March, 1988, 36 patients underwent open heart surgery without homologous blood transfusion were investigated. Patients with infective endocarditis and urgent surgical cases were excluded from this study. Out of 36 patients using hemoconcentrator, autologous blood and the Variable Prime Cobe Membrane Lung (VPCML), 28 patients (78%) could avoid homologous blood transfusion during the operation and 24 patients (67%) received no homologous blood throughout their hospital stay. Thus, the application of lower volume extracorporeal oxygenator system, reinfusion of residual pump volume using hemoconcentrator and predonated autologous blood could achieved cardiac surgery without homologous blood transfusions in the majority of patients. Moreover, the VPCML had sufficient gas transfer in adult patients with body weight ranging from 37 kg to 70 kg. In renal function, serum creatinine levels in patients without homologous blood were within normal limits throughout 1 month after surgery. However, creatinine level was significantly elevated at the third postoperative day in the homologous blood transfusion group. Thus, these results suggest that application of VPCML and hemoconcentrator combined with predonated autologous blood is useful to achieve open heart surgery without donor blood.

Blood Transfusion, Autologous↗