Background : The low hypoxic ventilatory response (HVR) has been suggested to be one of the pathophysiological features in high-altitude pulmonary edema (HAPE). Ventilatory responses to hypoxia vary widely depending on the length of hypoxic exposure. The pathophysiological role of HVR in the development of HAPE has not yet been well understood.
Methods : Isocapnic hypoxic exposure was induced to 12 Japanese HAPE susceptible subjects (HAPE-s) and 10 HAPE resistant subjects (HAPE-r) in Shinshu University at an altitude of 600 meters (m). A slope linear regression relating minute ventilation (V˙_E, L/min) to oxygen saturation (SpO₂, ％), V˙_E＝α^＊SpO₂＋β, was obtained in each of the subjects of HAPE-s and HAPE-r after 10-minutes (min) and 30-min isocapnic hypoxic exposure, respectively. The slope α parameter was the ratio of change of V˙_E (ΔV˙_E) to change of SpO₂ (ΔSpO₂) and the absolute slope α value was used for evaluation of HVR. In addition, the hypoxic ventilation decline (HVD) was calculated in the later phase of hypoxic exposures.
Results : The HVR was significantly lower in the HAPE-s than the HAPE-r subjects at 10-min (0.29±0.18 vs 1.13±1.21, p＝0.03) and 30-min (0.16±0.09 vs 1.01±1.08, p＝0.01) hypoxic exposure. Moreover, the HVR continuously declined in the HAPE-s subjects over the prolonged hypoxic exposure from 0.29±0.18 at 10-min hypoxic exposure to 0.16±0.09 at 30-min hypoxic exposure, resulting in 29.3％ of HVD in HAPE-s, in contrast to 3.1％ of HVD in the HAPE-r subjects over the prolonged hypoxia.
Conclusion : The HVR was not only significantly blunted but also continuously declined in the HAPE-s over a prolonged hypoxic exposure, which contributed to the failure in acclimatization to high-altitude hypoxia.

View full abstract

Background : Recently, several echocardiographic parameters have been proposed as predictors of the recurrence of persistent atrial fibrillation (psAF) after catheter ablation (CA). This study aimed to evaluate whether a decrease in inter-atrial septum (IAS) motion was associated with recurrence of psAF after CA.
Methods : A total of 103 consecutive patients who underwent CA for psAF were retrospectively reviewed. IAS motion was measured 48-72 hours before CA using transesophageal echocardiography. The primary outcome was AF recurrence beyond 3 months post-ablation. The follow-up period was 12 months after CA.
Results : PsAF recurrence after CA occurred in 29 (28.2％) patients. The median value of IAS motion was 4.1mm (interquartile range 2.4, 5.4), and the decline in IAS motion was an independent predictor of AF recurrence in a multivariate analysis of various models. Kaplan-Meier analysis showed that AF recurrence was significantly higher in the low IAS motion group (IAS motion < 4.2, n＝47) than in the high IAS motion group (IAS motion ≥ 4.2, n＝52) (log-rank test, p＝0.001). A negative correlation was observed between IAS motion and left atrial volume (LAV), and conversely, a positive correlation was found between IAS motion and left atrial appendage flow velocity. The low IAS motion group had a higher left atrial pressure (LAP) than the high IAS motion group.
Conclusions : PsAF recurrence after CA was associated with reduced IAS motion. Decreased IAS motion could be an important finding suggestive of left atrial remodeling as well as LAV enlargement and increasing LAP.

View full abstract

Solitary fibrous tumor (SFT) is a relatively rare tumor commonly localized in the pleura but can occur in any location of the body. However, SFT in the pelvis is very rare. We report a case with SFT in the obturator foramen. The patient was a woman in her 70s with the tumor in the left obturator foramen, found on CT images incidentally. Non-contrast CT images showed the tumor was well-delineated and of soft tissue density in the early phase of dynamic contrast-enhanced CT, marked tumor enhancement was seen. The delayed phase of dynamic contrast-enhanced CT showed persistent enhancement. T2-weighted images showed a high intensity tumor with a flow void within the tumor. Surgical resection was performed, and the tumor was diagnosed as SFT pathologically. To our knowledge, this is the first case of SFT located in the obturator foramen.

View full abstract

We describe a rare case of cyst formation in RCC metastasis to the liver, which showed extremely slow progression over 9 years.
A 60-year-old man under maintenance hemodialysis for renal failure due to polycystic kidney disease received a left nephrectomy for Stage I RCC 9 years earlier. Analysis of the tissue was histologically confirmed as clear cell RCC along with partial sarcomatous change. He was also noted as having a cyst formation tumor of 15mm in diameter at S6 in the liver, which was depicted as a non-contrasted lesion in the early phase and an iso-echoic lesion in the Kupffer phase by contrast-enhanced ultrasonography using Sonazoid, indicating that the lesion was not malignant. The hepatic cystic lesion had increased to a size of 60mm in diameter 5 years later, but exhibited no solid formation and resembled a hemorrhagic liver cyst. However, the lesion became gradually enlarged, with accompanying cystic lesions that were depicted as high-intensity MRI T2 images surrounded by a high-intensity area in MRI diffusion images along with a solid lesion showing reduced uptake of SPIO. Those findings suggested an angiosarcoma or liver metastasis of RCC. A tissue specimen of the tumor obtained after a right hepatic lobectomy displayed malignant cells on the wall of the cystic lesion, which was compatible with metastasis of clear cell RCC. Moreover, it was apparent that although the hepatic cystic tumor lesion was affected by hemorrhage, it was increased in size by the retention of serous components. Thus, a cystic, and not sarcomatous, component appeared to slowly enlarge the lesion. No additional metastasis was detected by PETCT after surgical treatment. Clinicians should consider hepatic metastasis of RCC when encountering a tumor in the liver, even a cystic lesion, in patients with a history of RCC.

View full abstract

At the age of 32, gravida 1 para 1, the patient delivered her first child by Cesarean section on the 1st day of the 38th week of pregnancy due to preeclampsia, and was referred to the hospital wishing for a second child. Pregnancy was not established by the timing method and artificial insemination with the husband (AIH), and irregular bleeding that continued from the follicular phase to the ovulation phase was observed during artificial insemination. At this time, fluid retention was also observed in the Cesarean section scar, and a diagnosis of Cesarean scar syndrome was made. As the patient did not desire for surgical treatment and wanted to step up fertility treatment, we decided to try to establish a pregnancy by reducing the endometrial retention by GnRH agonist, and started treatment by in vitro fertilization and embryo transfer.
Gonadotropin releasing hormone agonist (GnRH agonist) was administered for 6 months, and hysteroscopy 5 months after the start of administration showed no evidence of bleeding in the uterus, unlike before treatment. The pooling had disappeared. Considering that the environment in the uterus had improved, frozen embryo transfer was performed in the hormone replacement cycle, and pregnancy was established. On the 0th day of the 38th week of pregnancy, delivery was performed by scheduled Cesarean section.
In Cesarean section scar syndrome, the pooling of fluid in the scar and intrauterine cavity is considered to be one of the causes of infertility. In this case, administration of GnRH agonist suppressed bleeding from the Cesarean section scar and improved fluid retention in the uterus by hysteroscopy, which is considered to have contributed to the establishment of pregnancy. Currently, surgical treatment is often used for Cesarean section scar syndrome. Howrver, improvement of fluid retention in the uterine cavity by hormone therapy and/or hysteroscope and using in vitro fertilization and embryo transfer together may be an opinion for conservative therapy.

View full abstract