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Biomedical subjects

Koji Iida

Publications and source records attributed to Koji Iida.

26 records · Page 2Linked to original sources
PubMed2003

Hyperemia prior to acute brain swelling during rewarming of patients who have been treated with moderate hypothermia for severe head injuries.

OBJECT: The goal of this study was to elucidate the optimal time for rewarming of patients who have been treated with hypothermia for severe head injury. METHODS: Eleven patients with severe head injuries who had been treated by hypothermia underwent transcranial Doppler (TCD) ultrasonography examinations. The patients were divided into two groups: Group A consisted of three patients in whom acute brain swelling occurred during the rewarming period and Group B was composed of eight patients who displayed no significant intracranial hypertension during or after hypothermia therapy. In all patients, the mean flow velocity of the middle cerebral artery (FV(MCA)) recorded transcranially and the mean flow velocity of the internal carotid artery (FV(ICA)), recorded high in the neck, were monitored at 24-hour intervals after the patient was admitted to the hospital. In Group A, the FV(MCA) was normal at 48 hours (maintenance state of hypothermia) in each patient, and abnormal increases and peak values (> 100 cm/second) occurred from 96 to 144 hours postinjury (rewarming period). The FV(ICA), which was monitored concurrently also varied as the FV(MCA) increased. The pulsatility indices in the arteries decreased at the time of the peak FV(MCZ). The enhanced FV(MCA) was consistent with hyperemia because of the low FV(MCA)/FV(ICA) ratios (< 3). Two patients in whom jugular venous oxygen saturation was monitored were found to have high values (> 80%), representing hyperemia. All intracranial pressures (ICPs) that lay within the normal range at 48 hours postinjury elevated acutely after the peak FV(MCA). In Group B, both FV(MCA) and FV(ICA) values were normal at 48 hours postinjury and remained stable throughout the rewarming period. Values of ICP were also maintained within the normal range until the patients were weaned from hypothermia therapy. CONCLUSIONS: Hyperemia, detectable by TCD ultrasonography, may serve as an index in the prediction of acute brain swelling, and rewarming should be terminated when such a hemodynamic phenomenon is observed.

Acute Disease↗
PubMed2002

Telomerase activity and human telomerase reverse transcriptase mRNA expression are correlated with clinical aggressiveness in soft tissue tumors.

BACKGROUND: Telomerase is a ribonucleoprotein enzyme that extends telomere specific repeats on the ends of chromosomes. Telomerase activity has been detected frequently in various types of human tumors and has been associated with cell immortality and oncogenesis. Human telomerase reverse transcriptase (hTERT), a telomerase catalytic subunit, reportedly regulates telomerase activity. Little is known about telomerase activity and hTERT mRNA expression in soft tissue tumors. The objective of this study was to clarify the correlation between these two parameters and clinical aggressiveness in soft tissue tumors. METHODS: In 41 surgically resected soft tissue tumors, telomerase activity was measured by the fluorescence-based telomeric repeat-amplification protocol and hTERT mRNA expression was determined by real-time polymerase chain reaction. RESULTS: Telomerase activity was detected in 52% of sarcomas and in none of the benign soft tissue tumors (P < 0.05). Telomerase activity was found in 77% of 13 locally recurrent sarcomas and in 89% of 9 sarcomas with distant metastasis. The frequency of the presence of telomerase activity in those tumors was significantly greater compared with the frequency of telomerase activity in the other sarcomas (P < 0.05 and P < 0.01, respectively). All telomerase positive sarcomas expressed hTERT mRNA. The mean level of hTERT mRNA expression in sarcomas was significantly greater compared with the mean hTERT mRNA expression level in benign tumors (P < 0.05) and in locally recurrent sarcomas compared with primary sarcomas (P < 0.001). CONCLUSIONS: The results of the current study suggest that the detection of telomerase activity and the level of hTERT mRNA expression are useful markers for evaluating the clinical aggressiveness in soft tissue tumors.

Adult↗
PubMed2002

Evidence for hormone-responsive cleavage of gonadotropin-releasing hormone by the plasma membrane of ovarian cancer cells.

Gonadotropin-releasing hormone (GnRH) produced by ovarian cancer cells acts as a negative autocrine regulator in the ovarian cancer cell proliferation. GnRH and its analogs retard the proliferation of ovarian cancers bearing GnRH receptor, and thus the GnRH hydrolysis may be responsible for their growth. We determined the principal mechanism of GnRH hydrolysis by ovarian cancer cells and its coupling to GnRH receptor. GnRH cleaving activity was assessed by measuring the degradation of exogenous [3H]GnRH labeled at the N-terminal residue and the appearance of labeled degradation product. Approximately 98% of GnRH hydrolysis by plasma membrane from ovarian cancers surgically removed was accounted for by the cleavage at Tyr5-Gly6 to yield (1-5)GnRH. The GnRH degrading activity in the plasma membrane was approximately 6-fold higher than those in homogenate fraction. The membrane GnRH cleaving activity was metal ion-independent and sensitive to inhibition by N-ethymaleimide and endopeptidase inhibitors; characteristics suggestive of membrane-bound endopeptidase activity. No effects of buserelin and leuprolide on the [3H]GnRH hydrolysis at 4-fold higher concentration of the [3H]GnRH substrate suggested great resistance of the GnRH analogs toward the endopeptidase. GnRH degrading activity increased by 1.5-fold when the ovarian cancer Caov-3 cells were exposed to buserelin in intact cells prior to assay of cell membranes. These data demonstrate that GnRH is hydrolysed in the plasma membrane of ovarian cancer cells by the action of endopeptidase and provide the initial evidence for the functional coupling of the GnRH degradation to GnRH receptor activation.

Adenocarcinoma↗
PubMed2002

Effect of smoke inhalation injury on fluid requirement in burn resuscitation.

The effect of smoke inhalation injury on fluid requirement was assessed retrospectively. A total of 131 burn patients were classified into two groups: burn patients with smoke inhalation injury (Group IB: 73 patients) and burn patients without inhalation injury (Group B: 58 patients). Fluid resuscitation was commenced according to the Parkland formula and the infusion rate was modified to meet the main resuscitation goal of an hourly urine output of 1.0 to 2.0 ml/kg. Regression analyses were performed on the volume of fluid administered during the initial 24 hours after injury by burn size for each group. The linear equations obtained were Y (ml/kg/24 hrs) = 71.0 + 5.08 x %TBSA (Group IB) and Y = 39.7 + 5.14 x %TBSA (Group B). A substantial effect of inhalation injury on fluid requirement was speculated to be reflected in a y intercept difference of about 30 ml/kg/24 hrs. Thus, an increase in the fluid requirement related to the presence of inhalation injury was found to be independent and additional to burn injury.

Adolescent↗
PubMed2002

Circulating blood volume in burn resuscitation.

Circulating blood volume (CBV) was prospectively measured in patients with almost solely smoke inhalation injury (Group I: 10 patients) and in patients with severe cutaneous burn (Group B: 6 patients) consecutively until 96 hours after injury, to assess the effect of either injury on intravascular volume status by the pulse dye-densitometry method. All participants were treated by an ordinary fluid regimen based on the Parkland formula with an hourly urine output of 1.0 to 2.0 ml/kg for the resuscitation endpoint. CBV was also measured in 15 elective surgical patients for a control value (76.7+/-9.0 ml/kg). The level of CBV values in Group I was low, ranging from 54.4+/-6.9 ml/kg to 59.6+/-6.2 ml/kg (from 70.9% to 77.7% of control value), while in Group B from 48.5+/-5.5 ml/kg to 55.6+/-17.3 ml/kg (from 63.2% to 72.5%) until 72 hours after injury. There was no significant difference in CBV values between the two groups throughout the study period. We could elucidate the existence and extent of intravascular volume depletion in spite of optimal fluid treatment in both solely smoke inhalation injury and solely severe cutaneous burn. Almost solely inhalation injury was found to decrease CBV to less than that of severe cutaneous burn, which presumably led to the increased fluid requirement. Concerning the resuscitation endpoint in early burn treatment, this depletion in CBV must be taken in mind. Hourly urine output is speculated to be an effective and practical clue to manage a burn patient within permissive hypovolemia.

Adolescent↗
PubMedDate not supplied

Interfacial gaps following ceramic inlay cementation vs direct composites.

This study compared the interfacial integrity of Class II ceramic inlay restorations and direct resin composite restorations. The influence of a flowable resin composite liner was also evaluated. Class II DO cavities were prepared in 40 recently extracted mandibular molars and assigned to four treatment groups. Group A: direct composite restoration; Group B: Cerec inlays fabricated and cemented with a resin cement; Group C: adhesive lining with a flowable resin composite used prior to resin composite restoration; Group D: lining with a flowable resin composite prior to cementation of Cerec inlays. After finishing, polishing and thermocycling (4 degrees C and 60 degrees C x 500), the samples were cross-sectioned in a mesio-distal direction along the center of the fillings or inlays. The cross-sectioned surface was polished, and the adhesive interfaces between resin and enamel or dentin were observed under a scanning laser measurement microscope. Ceramic inlay restorations showed no interfacial gaps in enamel, but direct resin composite restorations showed a significantly higher incidence of gaps at the interface or cracks in the interfacial enamel (p=0.0002). No differences were found in the resin-dentin interfaces for both the inlay and direct resin composite restorations. The use of a flowable resin composite as an adhesive liner produced a significantly greater gap-free resin-dentin interface in Cerec inlay and direct resin composite restorations (p=0.0233 & 0.0009), but it did not reduce gap formation at the resin-enamel interface.

Cementation↗
PubMedDate not supplied

Effect of retinoblastoma tumor suppressor gene expression on chemosensitivity of human osteosarcoma cell lines.

We examined the effects of inactivation of the RB gene on chemosensitivity of human osteosarcoma cell lines, using the MTT assay and calculating the inhibition index. Although the human osteosarcoma cell lines HOS and MG63 have a wild-type RB gene, SaOS-2 and OSrb (established from retinoblastoma patient) have no active RB gene. We used these 4 cell lines in growth inhibition assays for doxorubicin, cisplatin and methotrexate, and assessed the chemosensitivity. In the growth inhibition assay for methotrexate, cell lines lacking an active RB gene were more resistant than cell lines with an active RB gene.

Antibiotics, Antineoplastic↗