Biomedical subjects

M Kamitomo

Publications and source records attributed to M Kamitomo.

23 records · Page 2Linked to original sources

PubMedDate not supplied

Effects of magnesium sulfate on the fetal heart rate response during acute hypoxemia in goats.

OBJECTIVE: The effects of magnesium sulfate on fetal heart rate (FHR) response during acute hypoxemia in goats were investigated. METHODS: The FHR responses due to hypoxemia during magnesium sulfate infusion (Mg study) were compared with those during vehicle infusion (controls) in six chronically instrumented goat fetuses at 125-130 days' gestation. RESULTS: Four-hour infusions of magnesium sulfate significantly increased fetal plasma concentrations of magnesium from 2.3 to 6.5 mg/dL. During the hypoxemic period, the fetal arterial oxygen pressure was significantly decreased from 29.0 +/- 2.5 to 14.6 +/- 2.6 torr in the controls, and from 28.9 +/- 3.9 to 13.7 +/- 4.7 torr during the Mg study. Neither arterial carbon dioxide pressure nor pH was significantly altered. In the controls, FHR was significantly decreased by hypoxemia, accompanied by increases in variability. In the Mg study, FHR was not significantly decreased by hypoxemia. Acute hypoxemia also increased the FHR variability during magnesium infusion, which was significantly reduced compared with those in the control population. CONCLUSION: Magnesium sulfate masks FHR-slowing responses during acute hypoxemia in fetal goats.

Animals↗

PubMedDate not supplied

Periodic fetal heart rate decelerations during 6 hours' hypoxemia induced in goats.

OBJECTIVE: To determine if fetal heart rate (FHR) decelerations periodically occur with uterine contractures during 6 hours' induced hypoxemia in goats. METHODS: In five chronically catheterized goat fetuses at 125-130 days' gestation, incidence of FHR decelerations was compared between 6 hours' control time and 6 hours' induced hypoxemia with two-way ANOVA and Duncan's multiple range test. Three other fetuses were used as controls for circadian rhythm. RESULTS: Fetal PaO2 was significantly decreased from 26.1 to 16.3 mmHg without acidemia. During hypoxemia, 42 decelerations were induced along with 5 initial decelerations during the acute phase hypoxemia. Incidence of decelerations increased significantly from 0.07 +/- 0.15 per hour in 6-hour controls to 1.40 +/- 0.28 per hour during 6 hours' induced hypoxemia. Short-term variability and long-term variability of the 42 decelerations were significantly increased. These variabilities were also increased during the 5 initial decelerations. Frequency of uterine contractures did not change during hypoxemia. There was an observable association of FHR decelerations with uterine contractures during hypoxemia. CONCLUSION: Fetal heart rate decelerations occurred periodically in association with uterine contractures during induced 6 hours' hypoxemia, which were characterized by slow onset and recovery with increases in variability.

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PubMedDate not supplied

Fetal glioblastoma: rapid growth during the third trimester.

We present a case of fetal glioblastoma which appeared after 28 weeks' gestation. The first ultrasonographic finding was an enlarged fetal head with right shifted falx cerebri at 31 weeks' gestation. At 33 weeks, a large and high echogenic mass in the left hemisphere and right enlarged ventricle was identified. Magnetic resonance imaging showed that the tumor was localized in the left hemisphere and a margin of the tumor was defined. Because fetal well-being judging from biophysical parameters was good and we considered that the tumor was resectable, a male fetus weighing 2,670 g was delivered at 34 weeks' gestation by cesarean section. However, he was inoperable due to consumptive coagulopathy and rapid growth of the tumor, and died on the 41st day of life.

Adult↗

PubMedDate not supplied

Hemangioma of the umbilical cord: stenotic change of the umbilical vessels.

We report a rare case of an umbilical cord hemangioma diagnosed by ultrasound at 16 weeks of gestation. The umbilical cord consisted of a hemangioma nodule and pseudocysts near the placental insertion, a large gelatin-like swelling adjacent to the nodule on its fetal side, and a short normal part extending to the navel. At 17 weeks of gestation, this condition resulted in the intrauterine death of the fetus. Microscopically, there were communications between the capillary of the hemangioma and the umbilical vessels, verifying the origin of the tumor. Moreover, the umbilical vein and one of the arteries changed stenotically due to the intravascular proliferation of the hemangioma. These findings indicate the possibility of a pathological association between the umbilical cord hemangioma and fetal demise due to impaired umbilical circulation.

Adult↗

PubMedDate not supplied

Magnesium sulfate and fetal plasma concentrations of epinephrine, norepinephrine, and vasopressin in response to acute hypoxemia in goats.

OBJECTIVE: We measured fetal plasma concentrations of epinephrine, norepinephrine, and vasopressin during acute hypoxemia in goats and tested whether hypermagnesemia altered these endocrine responses. METHODS: Five chronically catheterized goat fetuses at 124-129 days' gestation were used. After 4 hours of infusion (magnesium or vehicle as controls), 30 minutes of hypoxemia was induced by infusing nitrogen gas through a maternal tracheal catheter. Fetal plasma concentrations of epinephrine, norepinephrine, and vasopressin were measured before and during hypoxemia. Both magnesium sulfate and vehicle infusions were performed in each animal. Repeated-measures analysis of variance (ANOVA) and two-way ANOVA with post hoc test were used to determine statistical significance. RESULTS: During hypoxemia, fetal PO(2) decreased significantly from 30 to 14 mmHg with no significant changes in fetal pH or PCO(2) in both groups. Fetal heart rate was reduced significantly by hypoxemia, but to a lesser extent in the magnesium group (change in decrease in fetal heart rate: 41 beats per minute [bpm] in controls versus 26 bpm with magnesium). Mean blood pressure did not change significantly during hypoxemia in both groups. Fetal plasma concentrations of epinephrine, norepinephrine, and vasopressin significantly increased from the prehypoxemic values both with magnesium and in controls. There were no significant differences in these hormone concentrations between magnesium and the controls. CONCLUSION: Magnesium sulfate had no effect on fetal plasma concentrations of vasopressin, epinephrine, and norepinephrine during acute hypoxemia.

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