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Biomedical subjects

J Kawabe

Publications and source records attributed to J Kawabe.

64 records · Page 4Linked to original sources

Cloning and characterization of a sixth adenylyl cyclase isoform: types V and VI constitute a subgroup within the mammalian adenylyl cyclase family.

A sixth member of the mammalian adenylyl cyclase family has been isolated from a canine cardiac cDNA library. This isoform is more highly homologous to type V than to the other adenylyl cyclase types; sequence similarity is apparent even in the transmembrane regions where the greatest divergence among the types exists. Type VI mRNA expression is most abundant in heart and brain; however, unlike type V, a low level of expression is also observed in a variety of other tissues examined. Type VI adenylyl cyclase can be stimulated by NaF, guanosine 5'-[gamma-thio]triphosphate, and forskolin but not by Ca2+/calmodulin, whereas it is inhibited by adenosine and its analogues. Comparison of both their structural and biochemical properties suggests that types V and VI constitute a distinct subgroup of the mammalian adenylyl cyclase family.

Adenosine↗

[Gd-DTPA-enhanced MR imaging of the normal facial nerve].

We performed a prospective imaging study of the normal facial nerve within the temporal bone before and after injection of Gd-DTPA. The study included 29 patients using a 1.5T superconducting unit and 40 nerves (right: 21; left: 19) were available for analysis. There was no enhancement of the facial nerve within the internal auditory canal in the entire series. However, the enhancement at the labyrinthine segment was observed in one nerve (3%); at the geniculate ganglion in seven (18%); at the tympanic segment in 18 (45%) and at the mastoid segment in 28 nerves (70%). Our results indicate that enhancement of the facial nerve in normal subjects is not a rare condition.

Adolescent↗

Isolation and characterization of a novel cardiac adenylylcyclase cDNA.

A novel adenylylcyclase cDNA (type V) was isolated from a canine heart cDNA library. Northern blotting indicates that the expression of this message is most abundant in heart with a lesser amount in brain but is absent in a variety of other tissues including lung, kidney, skeletal muscle, lymphocyte, and testis. The putative protein product predicted from the cDNA sequence has the motif of tandem six-transmembrane spans separated by a large hydrophilic cytoplasmic loop as seen in other members of the adenylylcyclase family. When this protein is expressed using a CMT cell transient expression system, the adenylylcyclase activity was stimulated by NaF, GTP gamma S, and forskolin, but not by calmodulin. The activity was inhibited in a concentration-dependent manner with either P-site active agents such as adenosine or in the presence of calcium. These data indicate that the protein encoded by this cDNA is adenylylcyclase with the biochemical features characteristic of the cardiac isoform.

Adenosine↗

[Effects of chronic volume loading on atrial natriuretic peptide release in human].

In the present study, we investigated whether release of hANP increases during mild and long-term volume loading. Eight lung cancer patients in good performance state (five men and three women, 35 to 68 years), who needed to have pre-hydration for cancer chemotherapy with cisplatin, were infused with about seven liters of isotonic saline over 48 hours through Swan-Ganz catheter placed in the pulmonary artery. The mean infusion rate was 0.042 ml/min.kg body weight. During the infusion, change in plasma volume (delta PV) increased by 5.8 + 3.3 (mean +/- SE) %. Right atrial pressure (RAP) did not change significantly, and pulmonary artery wedge pressure (PAWP) increased from 4.3 +/- 1.0 to 5.8 +/- 0.7 mmHg. Plasma hANP was significantly elevated from 50.6 +/- 0.7 to 105.1 +/- 19.3 pg/ml by the second day of the infusion with a suppression of plasma renin activity (PRA) and aldosterone, though plasma ADH did not change. The infusion rate at 20:00 on the first day was the same as that on the second day. Further increase in plasma hANP was shown at 20:00 on the second day compared with the level at the same time on the first day, though RAP, PAWP and delta PV did not change. These results indicate that mild and chronic volume loading increases plasma hANP, and suggest that the prolongation of volume expansion plays an important role in the releasing of hANP in humans.

Adult↗

Positron emission tomography using 2-[(18)F] fluoro-2-deoxy-D-glucose in the diagnosis of uterine leiomyosarcoma: a case report.

The preoperative diagnosis of uterine leiomyosarcoma (LMS) is very difficult. Magnetic resonance (MR) imaging is usually used for it; however, precise diagnosis by MR imaging is limited to typical LMS with coagulative tumor cell necrosis. We presented a case of LMS that was diagnosed preoperatively by positron emission tomography (PET) using 2-[(18)F] fluoro-2-deoxy-D-glucose (FDG).

Aged↗

Early diagnosis and evaluation of therapy in postoperative recurrent cervical cancers by positron emission tomography.

Positron emission tomography (PET) using 2-[18F]fluoro-2 deoxy-D-glucose (FDG) was performed on two uterine cervical cancer patients in whom recurrent tumors, one pelvic and the other at the vaginal wall had not been precisely diagnosed using the usual imaging examinations. One recurrence was confirmed by the acccumulation of FDG to the pelvic mass as detected by magnetic resonance imaging (MRI). During chemotherapy, changes in FDG-PET findings were detected earlier than those in MRI. In the other, PET detected a recurrent tumor that could not be found by MRI, and was also useful for evaluating chemotherapeutic effects. These cases suggest that PET with FDG can be a useful examination not only for diagnosing recurrent cervical cancer after radical hysterectomy, especially pelvic recurrence, but also for evaluating chemotherapeutic effects on recurrent cancers.

Female↗

The role of 18F-fluoro-2-deoxy-D-glucose positron emission tomography (18F-FDG-PET) in the diagnosis of recurrence and lymph node metastasis of cervical cancer.

The usefulness of positron emission tomography with 2-[18F]-fluoro-2-deoxy-D-glucose (FDG-PET) in diagnosing recurrence and lymph node metastasis of uterine cervical cancer was evaluated as a preliminary study. The FDG uptake of 13 cervical cancer patients, including 4 patients with recurrence, was evaluated. The FDG uptake of the cervices of 5 patients who underwent PET studies for non-cervical tumors were used as control. In 2 patients who had undergone radical hysterectomy, we compared the diagnosis of lymph node metastasis based on FDG-PET and magnetic resonance imaging. The FDG uptake in the 9 primary cervical cancers was greater than that in normal cervices (p=0.025). Examination of the 4 recurrent tumors revealed a higher FDG uptake than that in normal cervices (p=0.0022). Metastatic lesions in lymph nodes showed an accumulation of FDG on the PET scan. In conclusion, FDG-PET may be an effective diagnostic tool for detecting recurrence and lymph node metastasis of uterine cervical cancers.

Adult↗

Diagnosis of metastasis of ovarian clear cell carcinoma to the peritoneum of the abdominal wall by positron emission tomography with (fluorine-18)-2-deoxyglucose.

A 43-year old woman, operated on for ovarian clear cell carcinoma (stage IIc) four years previously was found to have a small mass under the abdominal wall in the right lower quadrant of the abdomen. Neither diagnostic imaging (ultrasonography and MRI) nor tumor markers showed any evidence of recurrence, but positron emission tomography revealed a hot spot area, and it was diagnosed as recurrence of the ovarian carcinoma. The postoperative histopathological diagnosis was metastasis of ovarian carcinoma to the peritoneal wall.

Adenocarcinoma, Clear Cell↗

Combined diagnostic imaging for retroperitoneal schwannoma.

Retroperitoneal tumors are occasionally encountered by gynecologists, and differential diagnosis from adnexal tumors is important, however, it is difficult in many cases. We report a case in which we preoperatively diagnosed a benign solid tumor in the retroperitoneum of the pelvic cavity on the basis of a variety of diagnostic images, including FDG-PET. Postoperative histological examination showed a benign schwannoma in the pelvis. We discuss the usefulness of FDG-PET combined with MRI and other diagnostic images as a means of differentiating between the characteristics of retroperitoneal tumors.

Biomarkers, Tumor↗