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Biomedical subjects

H Iwama

Publications and source records attributed to H Iwama.

At least 19 recordsLinked to original sources
PubMed2002

Spinal anesthesia hypotension in elective cesarean section in parturients wearing extra-strong compression stockings.

We have routinely applied an extra-strong graduated compression stocking to cesarean section patients to reduce the incidence of spinal anesthesia hypotension. Because bupivacaine has recently become available in Japan, we compared the incidence of spinal hypotension using either 2.0 ml of hyperbaric 0.3% dibucaine or 0.5% bupivacaine. There were 98 full-term parturients wearing the stocking who received 2.0 ml injection of dibucaine or bupivacaine for elective cesarean section. When systolic blood pressure decreased to 90-100 mm Hg or to less than 70% of the pre-anesthesia value, ephedrine was injected intravenously. There was no significant difference in systolic blood pressure or heart rate during spinal anesthesia between the dibucaine and bupivacaine groups. Although the demographic data and various data related to anesthesia or surgery were similar in the groups, the fluid volume and the dose and incidence of ephedrine injection during anesthesia showed significant differences: the mean dose was 3.6 and 1.5 mg and the incidence was 41% and 19% in the dibucaine and bupivacaine groups, respectively. Spinal anesthesia using bupivacaine results in a lower incidence of spinal hypotension compared with dibucaine and, in combination with fitting the extra-strong stockings onto both legs, is clinically useful for cesarean sections.

Adult↗
PubMed2002

Circulatory, respiratory and metabolic changes after thigh tourniquet release in combined epidural-propofol anaesthesia with preservation of spontaneous respiration.

Twelve elderly patients undergoing total knee arthroplasty received lumbar epidural anaesthesia and propofol infusion at 5 mg.kg(-1).h(-1) following a 1.5-2.0 mg.kg(-1) bolus dose with preservation of spontaneous respiration via a laryngeal mask airway. Circulatory, respiratory and metabolic variables were measured before and 1, 3, 5, 15 and 30 min after release of a pneumatic thigh tourniquet. The blood pressure was decreased at all time-points and the respiratory rate increased at 1 min. The P(a)CO(2) was increased only at 1 min. Arterial blood pH and base excess were decreased at 1 and 3 min and 1, 3 and 5 min, respectively. Arterial blood lactate levels were increased at all times. These characteristics were considered to be identical to those under regional anaesthesia with conscious spontaneous respiration, showing that spontaneous respiration under this anaesthetic regimen has a similar respiratory capacity to that of conscious spontaneous respiration.

Aged↗
PubMed2001

Increase of peak expiratory flow by atropine is dependent on circadian rhythm.

PURPOSE: To examine whether the bronchodilatory effect of atropine differs in the evening from the morning. METHODS: Thirteen adult healthy volunteers with no oral medication intake were studied. At 1600, peak expiratory flow (PEF) was measured three times, and the highest value recorded. Subsequently, the volunteer received 0.01 mg(-1) x kg(-1) atropine im, and the PEF was measured every 30 min for 180 min. On a different day, at 0400, the effect of atropine on the PEF was measured again in the same way. RESULTS: The PEF values before atropine at 1600 and 0400 were 485 +/- 92 (350-730) and 458 +/- 76 (340-600) 1 min(-1),(P < 0.05). There was no difference in PEF values between the 1600 and 0400 time courses after atropine. The PEF value was increased only at 90 min at 1600 (P = 0.0012), but at 30, 60, 90 and 120 min at 0400 (P = 0.0001). CONCLUSION: Atropine administration has a weak bronchodilatory effect in the evening, but a stronger effect in the morning. Airways are narrower in the morning than in the evening, and this change is inhibited by atropine such that the PEF values are restored to those observed in the evening.

Adult↗
PubMed2001

Extra-strong graduated compression stocking reduces usage of vasopressor agents during spinal anesthesia for cesarean section.

Because a standard type of graduated compression stocking is not effective for the prevention of spinal anesthesia hypothension during cesarean section, we have used an extra-strong type of graduated compression stocking. This study examined whether the extra-strong stocking reduces usage of vasopressor agents. Forty-eight and 47 full term parturients were fitted with the standard stocking and the extra-strong stocking, respectively. Spinal anesthesia was performed by injecting 2.0 ml 0.3% dibucaine hyperbaric solution. When systolic blood pressure decreased to 90-100 mmHg or to less than 70% of the pre-anesthesia value, ephedrine was injected. There was no significant difference in systolic blood pressure or heart rate during spinal anesthesia between the groups. The mean dose of ephedrine injected during anesthesia was 12.2 and 4.3 mg, and the incidence of ephedrine injected was 85 and 49%, in the standard and extra-strong stocking groups, respectively. The extra-strong stocking group showed significantly lower values. Fitting the extra-strong stocking on both legs for cesarean sections undergoing spinal anesthesia reduced usage of vasopressor agents, suggesting a promising use of this stocking for non-invasive prophylaxis.

Adolescent↗
PubMed2001

Bradykinin-associated reactions in white cell-reduction filter.

PURPOSE: The purpose of this study was to examine the effect of temperature on bradykinin generation during blood transfusion using positively charged (positive filter), negatively charged (negative filter), and neutral (neutral filter) filters. MATERIALS AND METHODS: Whole blood collected from six volunteers at 4 degrees C or 37 degrees C was passed through the positive or negative filter. In six surgical patients during surgery, autologous blood transfusion at 37 degrees C was initiated through the positive filter, and the same transfusion was reintroduced through the negative filter. Whole blood from another six volunteers at 4 degrees or 37 degrees C was passed through the neutral filter. RESULTS: The positive filter did not generate bradykinin at any temperature, whereas the negative filter generated bradykinin by approximately 4,000-fold when warm blood was used but did not at cool blood. Blood pressure decreased and heart rate increased during warm blood transfusion using the negative filter but did not change using the positive filter. Plasma bradykinin levels increased in patients with use of the negative filter. The neutral filter generated bradykinin when warm blood was used but at levels lower than for the negative filter. CONCLUSIONS: Use of negative filter results in the temperature-dependent generation of bradykinin, which becomes a potential anaphylatoxin when warm blood is used.

Adult↗
PubMed2001

Telomere dynamics in myelodysplastic syndromes and acute leukemic transformation.

Myelodysplastic syndromes (MDS) are characterized by cytopenias in the blood and dysplastic features in the hematopoietic cells. Although the impact of cytogenetic abnormalities is considerable for prognosis, the exact genetic mechanism of MDS remains undetermined. In this study we assessed cytogenetic changes, microsatellite alterations, and telomere dynamics in order to obtain further insight into the pathogenesis of MDS. Thirty-three percentage of MDS patients and 60% of post-MDS acute leukemia (post-MDS AML) had de novo microsatellite changes. In the MDS phase, however, > 60% of patients showed reduction of telomere lengths without microsatellite changes, indicating that telomere reduction in most MDS patients does not seem to be directly linked to genome instability, or that reduction of telomere length does not induce microsatellite changes in the MDS phase. Some MDS patients had microsatellite changes without telomerase elevation, indicating that genome instability might accumulate during the disease progression in some MDS patients, and this condition (cellular senescence) may be related to ineffective hemopoiesis in MDS patients. In contrast, 40% of post-MDS AML patients had elevated telomerase activity with microsatellite changes, indicating that approximately 40% of patients with post-MDS AML patients had accumulation of genome instability resulting in elevated telomerase activity in an attempt to obtain genetic stability. However, the remaining MDS patients had microsatellite changes without telomerase up-regulation, suggesting that some MDS had genome instability even after leukemic transformation. Most MDS patients with elevated telomerase activity in the AML phase had elevated telomerase activity even in the MDS phase without apparent change in telomere length before and after leukemic transformation. These findings indicate that telomerase activity in the MDS phase may be independent of telomere length, although telomere shortening seems to be related to genomic instability, and this process may be linked to apoptosis of MDS cells.

Cell Transformation, Neoplastic↗
PubMed2001

Impaired telomere regulation mechanism by TRF1 (telomere-binding protein), but not TRF2 expression, in acute leukemia cells.

Telomere regulation is suggested to be an important mechanism in cellular proliferation and cellular senescence not only in normal diploid cells but also in neoplastic cells, including human leukemia cells. We studied the possible correlation among telomere length, telomerase (a ribonuclear protein that synthesizes the telemeres de novo) activity, hTERT (a catalytic subunit of telomerase) expression, and TRF1 and TRF2 (telomere DNA binding proteins) expression in human acute leukemia cells. The hTERT expression level was strongly associated with telomerase activity (P=0.0001), indicating that the expression level of the catalytic subunit (hTERT) regulates telomerase activity in human acute leukemia cells. TRF1 expression, which is believed to control telomere length, was significantly elevated in patients with acute lymphoblastic leukemia (ALL) (P=0.0232) compared to those in acute myeloid leukemia (AML); TRF1 expression tended to be higher in patients without telomere shortening (P=0.077) and in those with hTERT expression (P=0.055). This indicates that TRF1 may act to monitor telomere length under the condition of up-regulated telomerase activity in some neoplastic cells. In contrast, TRF2 expression in acute leukemia did not show any correlation with telomere parameters in this study. Although the precise regulation mechanism of telomere length is still uncertain, these results may suggest that regulation of telomere length is partially associated with TRF1 expression, whereas dysfunction of TRF1 expression may be speculated in a subset of acute leukemia.

Adolescent↗
PubMed2000

Genetic mapping of the rat mutation creeping and evaluation of its positional candidate gene reelin.

We have previously described a rat autosomal recessive mutation, creeping (cre), causing severe ataxia and disarrangement of neuronal cells in the central nervous system. The mutant strain has recently been successfully inbred, named Komeda Zucker creeping (KZC) rat. In the present study, we have performed a genetic analysis of the creeping mutation, and mapped it to rat Chromosome (Chr) 4. Comparative mapping, together with the similarity of the phenotype, suggested that the creeping mutation is homologous to the mouse reeler mutation. In fact, reelin expression was markedly reduced in the homozygous mutant (cre/cre) animals compared with the normal littermates. Thus, the KZC rat should become a useful biological model with a novel mutation in the reelin gene.

Animals↗
PubMed2000

Serum concentrations of soluble Fas antigen and soluble Fas ligand in mother and newborn.

We measured soluble Fas antigen and soluble Fas ligand, which are considered to be an apoptotic substance, in maternal serum, umbilical cord serum and amniotic fluid during cesarean section at full term pregnancy. Seventeen healthy parturients with no fetal distress were studied. Soluble Fas antigen showed no different levels between these measurement sites. Soluble Fas ligand showed a difference, in which umbilical serum level was significantly higher than maternal serum and amniotic fluid levels. The present results suggest high serum levels of soluble Fas ligand in newborn. However, the reason for this evidence is entirely unknown.

Adult↗
PubMed2000

Concentrative relationship between polymorphonuclear elastase and urinary trypsin inhibitor in amniotic fluid.

In the amniotic fluid, urinary trypsin inhibitor (UTI) seems to inhibit polymorphonuclear elastase (PMNE) activity. The PMNE and UTI concentrations in normal amniotic fluid at 16-20 and 38-40 gestational weeks were measured. The PMNE concentration increased significantly at 38-40 weeks, whereas UTI concentration decreased significantly. According to concentrative relationships between both substances, PMNE may be activated more at the full term pregnancy. Since PMNE-induced tissue injury potentially causes degradation of amniotic collagen, the present result suggests that the quotient of PMNE and UTI concentrations is a reliable index to estimate the occurrence of rupture of the membranes.

Abortion, Induced↗
PubMed2000

Refractory anemia with ringed sideroblasts with a low IPSS score progressed rapidly with de novo appearance of multiple karyotypic abnormalities and into acute erythroleukemia (AML-M6A).

We report here a case of refractory anemia with ringed sideroblasts (RARS) with a low risk group by the International Prognostic Scoring System (IPSS) at the time of diagnosis but had a rapid disease progression. Although the patient showed a normal male karyotype at the time of RARS diagnosis, his marrow cells had del(5)(q14) and add(17)(p12) abnormalities 2 months after the diagnosis, and later the marrow cells had multiple abnormalities and the patient expired 6 months after the initial diagnosis of RARS. The patient was diagnosed as having RARS with a low risk group by the IPSS classification, however, one should keep in mind that some patients with myelodysplastic syndromes with low risks by either the French-American-British (FAB) classification or the IPSS classification may have progressive disease and subsequential cytogenetic analysis could predict the disease progression.

Acute Disease↗
PubMed2000

Global brain ischemia produced by clamping left subclavian artery and bicarotid trunk in the rabbit.

Thirty-five rabbits were divided randomly into 5 groups: sham operation, 10 minutes clamping bicarotid trunk (partial ischemia, PI), and 3 groups of 5, 7, and 10 minutes clamping left subclavian artery and bicarotid trunk (global ischemia, GI). Systolic arterial pressure increased slightly in the PI group, but doubled in the GI groups during clamping. Heart rate did not change in the PI group, but decreased transiently in the GI groups during clamping. Brain temperature decreased gradually in the GI groups during clamping, but did not change in the PI group. Necrotic changes were present 96 hours later in approximately 50% of the hippocampal CA1 cells in the GI groups, but in none of the cells in the PI and sham operation groups. The present results may indicate that clamping left subclavian artery and bicarotid trunk in the rabbit brings about global brain ischemia.

Animals↗
PubMed2000

Propofol dosage achieving spontaneous breathing during balanced regional anesthesia with the laryngeal mask airway.

STUDY OBJECTIVE: To assess an anesthetic technique achieving spontaneous breathing through the laryngeal mask airway (LMA) during combined epidural block and propofol anesthesia. DESIGN: Prospective, consecutive case series study. SETTING: Operating room at a general hospital. PATIENTS: 112 ASA physical status I and II adult surgery patients; 32 patients for lower extremity surgery are enrolled into study 1, and 30 patients for lower extremity surgery and 50 patients for lower abdominal gynecology surgery are enrolled into study 2. INTERVENTIONS: In study 1, patients were given 1.5 to 2.0 mg/kg followed by a 3 mg/kg/h of infusion of propofol, after epidural block, and they were fitted with the LMA. Thirty minutes after induction, the dose of propofol was increased to 4, 5, 6, and 7 mg/kg/h every 15 minutes. In study 2, the patients were given 1.5 to 2.0 mg/kg and 5 mg/kg/h of propofol and the LMA insertion, after epidural block. MEASUREMENTS AND MAIN RESULTS: PaO(2)/FIO(2), PaCO(2), tidal volume or respiratory rate, blood pressure, heart rate, and eye opening and motor response scales in conformity with Glasgow coma scale were recorded. Study 1 suggested an induction dose of 1.5 to 2.0 mg/kg and an infusion of 5 mg/kg/h as an appropriate dose to preserve spontaneous breathing with the LMA and to maintain reasonable depth of anesthesia. Study 2 showed that respiratory and circulatory conditions, depth of anesthesia, and other data related to anesthesia were clinically acceptable. CONCLUSIONS: The best infusion dose of propofol to achieve spontaneous breathing with the LMA seems to be 5 mg/kg/h, and the present balanced regional anesthesia with the LMA, using propofol infusion at 1.5 to 2.0 mg/kg and 5 mg/kg/h combined with epidural block, may be useful in clinical practice for lower extremity and lower abdominal gynecologic operations.

Adult↗
PubMed2000

Intermittent pneumatic compression on the calf improves peripheral circulation of the leg.

PURPOSE: The aim of this study was to examine whether intermittent pneumatic compression (IPC) increases peripheral circulation locally in order to assess the use of IPC for prevention of deep venous thrombosis. MATERIALS AND METHODS: Seventy adult patients receiving major gastrointestinal surgery were studied. On postoperative day 1, calf-length garments were fitted onto both calves and deep temperature thermometers were put on both plantae. The IPC was applied randomly to either the left or right calf under 40 mm Hg pressure for 150 minutes. Bilateral plantar deep temperatures, as a reflection of peripheral circulation in the lower extremity, the tympanic temperature, mean blood pressure, and heart rate were recorded at 15-minute intervals. RESULTS: IPC compression was applied to 31 left and 39 right calves. The plantar deep temperature in the compressed calf was higher than in the noncompressed calf, and increased significantly, whereas the noncompressed calf showed no temperature change. The tympanic temperature, mean blood pressure, and heart rate did not change during the experiment. CONCLUSIONS: The results suggest that IPC has the effect of improving peripheral circulation, which supports the use of IPC to prevent deep venous thrombosis.

Adult↗
PubMed2000

Measurement of soluble Fas antigen and ligand in circulating serum and intra-abdominal or cerebrospinal fluid during gastrointestinal or cerebrovascular surgery.

PURPOSE: Soluble Fas antigen (sFas) and ligand (sFasL), which are associated with apoptosis, have not been evaluated in gastrointestinal or cerebrovascular surgery. The aim of this study was to measure these substances in serum, intra-abdominal fluid, or cerebrospinal fluid, and to speculate a pathophysiologic role for Fas-FasL apoptosis in surgery. MATERIALS AND METHODS: Arterial blood and intraabdominal or cerebrospinal fluid were collected at intervals from 27 gastrointestinal surgical patients, 10 cerebrovascular surgical patients, and 10 spinal anesthesia patients. RESULTS: Serum sFas levels did not change during and after surgery. Intra-abdominal and cerebrospinal sFas levels were identical to and lower than those in serum. Serum sFasL levels did not change during surgery, but decreased after surgery. Intra-abdominal and cerebrospinal sFasL levels were higher than and identical to those in serum. In spinal anesthesia, cerebrospinal sFas and sFasL levels were lower than those in serum. CONCLUSIONS: Serum sFasL decreases after surgery, whereas intra-abdominal or cerebrospinal sFasL increases, although sFas in each site does not change, suggesting redistribution of activated lymphocytes into local surgical wounds and induction of apoptosis in this site.

Aged↗
PubMed2000

Continuous monitoring of lower thoracic epidural pressure.

PURPOSE: The aim of this study was to examine whether the epidural pressure (EPIP) can be monitored for a long period of time using the continuous epidural infusion via the lower thorax. MATERIALS AND METHODS: Twenty-one adult patients undergoing gastrointestinal surgery had an epidural catheter inserted via the lower thoracic interspace. After induction of general anesthesia, continuous infusion of local anesthetic at a rate of 4 to 5 mL/h was applied epidurally. A pressure transducer was connected to the epidural catheter and the EPIP was monitored. During surgery, changes in the EPIP were monitored at 0, 5, and 10 cm H2O of positive end-expiratory pressure (PEEP). On postoperative day 1, 2, and 3, the EPIP was measured in the supine position, the Queckenstedt test, and the 30 degrees head-up position. RESULTS: The EPIP was monitored continuously and stably during surgery and until postoperative day 3, it increased significantly at 5 and 10 cm H2O PEEP, and increased and decreased significantly in the Queckenstedt test and the head-up position, respectively. CONCLUSION: Continuous epidural infusion at a rate of 4 to 5 mL/h via the lower thorax allows stable monitoring of the EPIP over a long period of time.

Adult↗