Biomedical subjects

Y Tanabe

Publications and source records attributed to Y Tanabe.

At least 217 records · Page 12Linked to original sources

PubMed1992

Neuroradiological findings in children with congenital myotonic dystrophy.

We studied seven children with congenital myotonic dystrophy, aged 2.1-8.3 years, and the results of computed tomography and magnetic resonance imaging of the brain were analyzed and neurological development was assessed from the neonatal period. We found that ventricular dilatation that had been seen on the first day of life in two of three infants had not progressed in sequential follow-up computed tomography scans taken at intervals of one to six years. Also, in T2-weighted magnetic resonance imagings, areas of periventricular hyperintensity were identified in all children, as well as areas of subcortical hyperintensity in one child. Further, an asphyxial episode had occurred at birth in five patients and the extent of the periventricular hyperintensity was found to correlate significantly with Apgar scores, indicating that the degree of perinatal asphyxia that had occurred was responsible for the abnormalities uncovered by the magnetic resonance imagings. However, there was no correlation between the neurodevelopment outcome and the extent of the periventricular hyperintensity or ventriculomegaly. Therefore, in patients with congenital myotonic dystrophy, a neonatal episode of asphyxia can be responsible for a finding of periventricular hyperintensity, but it is unlikely that an integral part of the mental retardation is attributable to brain damage due to perinatal asphyxia.

Apgar Score↗

PubMed1992

Clinical analysis of a series of vertebral aneurysm cases.

We reviewed 38 cases of aneurysms of the vertebral artery treated over the last 10 years: 26 (68%) located at the junction of the vertebral and posterior inferior cerebellar arteries, 10 (26%) at the vertebral artery, and 2 (5%) at the vertebrobasilar union. There were three distinct forms of aneurysms: 20 saccular (53%), 10 fusiform (26%), and 8 dissecting (21%). Among these 38 aneurysms, 33 (87%) had ruptured: 18 of the saccular aneurysms (90%), all 10 of the fusiform aneurysms (100%), and 5 of the dissecting aneurysms (63%). Computed tomography of the 28 ruptured aneurysms revealed diffuse subarachnoid hemorrhage in the basal cistern combined with intraventricular hemorrhage in 24 cases (86%). Magnetic resonance imaging was useful for differentiating between fusiform and dissecting aneurysms. Abnormalities such as a double lumen of the vertebral artery were demonstrated in four of the dissecting aneurysms. The overall surgical results were good for 22 of the 27 surgically treated cases (81%). New bleeding was observed in 8 (24%) of the 33 ruptured aneurysms. The rate of new bleeding was high (60%) in the patients with dissecting aneurysms, and occurred mostly in the acute stage. The incidence of vasospasm was 27%, and only two patients suffered permanent neurological deficits. These findings indicate that the rate of new bleeding tends to be high in patients with saccular and dissecting aneurysms, and thus, they should be treated as early as possible. A preoperative balloon occlusion test should be conducted if proximal occlusion of the vertebral artery is necessary, since proximal occlusion is not always safe, despite angiographic evidence of sufficient contralateral arterial flow.

Aortic Dissection↗

PubMed1992

Importance of coronary artery spasm in alcohol-related unexplained syncope.

To examine the role of coronary artery spasm in patients with syncope after alcohol ingestion, we performed an intracoronary ergonovine provocation test in 7 male patients (39 to 73 years old, mean 54 years) with alcohol-related syncope which remained unexplained despite noninvasive cardiovascular and neurological examinations. No patients had structural heart disease or significant coronary artery stenosis. Ergonovine was continuously infused into each coronary artery at a rate of 10 micrograms/min for up to 5 min. Coronary artery spasm with ST-segment elevation was induced in 4 of 7 patients. Chest pain before syncope or history of chest pain were not present in 3 of 4 patients with a positive ergonovine test. Multivessel coronary artery spasm was induced in 3 patients. One patient presented with triple vessel coronary artery spasm progressing to near syncope as a result of profound hypotension and ventricular tachycardia during provocation. Coronary artery spasm was promptly relieved by intracoronary isosorbide dinitrate infusion. All patients with a positive ergonovine test were treated with calcium antagonist and did not experience syncope during follow-up. These results suggest that coronary artery spasm is one of the important causes of syncope after alcohol ingestion.

Adult↗

PubMed1992

High prevalence of coronary artery spasm in survivors of cardiac arrest with no apparent heart disease.

The pathogenesis of cardiac arrest in the absence of any apparent heart disease remains unclear. Based on the hypothesis that coronary spasm may be a cause of cardiac arrest in the absence of apparent heart disease, ergonovine testing and/or electrophysiologic studies (EPS) were performed to evaluate the cause of cardiac arrest. Fourteen patients resuscitated from cardiac arrest had no apparent heart disease. A spontaneous episode of angina with ST-segment elevation occurred in 4 patients while under observation. Ergonovine testing was performed in 9 patients, and coronary spasm was induced in 5. EPS were performed in 8 patients, including 3 patients with coronary spasm. No electrophysiologic abnormalities were found in the 3 patients with coronary spasm. Ventricular fibrillation was induced by programmed ventricular stimulation in 2 patients with documented ventricular fibrillation at the time of resuscitation. All but one of the patients with coronary spasm had chest pain preceding cardiac arrest or at least a history of chest pain at rest, while 4 of 5 patients without coronary spasm had no prodromal symptoms. Patients with coronary spasm had a good prognosis when treated with a Ca-antagonist and/or long-acting nitrate. In conclusion, coronary spasm is the most frequent cause of cardiac arrest in cardiac arrest survivors with no apparent heart disease. Ergonovine testing should be performed to evaluate the cause of cardiac arrest when patients have no apparent heart disease.

Cardiac Pacing, Artificial↗

PubMed1992

Brain tumors manifesting as intracranial hemorrhage.

The clinical course and computed tomographic (CT) findings of 23 patients with brain tumors manifesting as tumoral hemorrhage were reviewed. The most common symptoms were headache and clouding of consciousness. A CT finding of a lesion located next to a solid or irregular clot indicated intratumoral hemorrhage. Precontrast CT demonstrating an indent on the hematoma surface was a valuable indicator of tumoral hemorrhage. A CT finding of accumulated levels of blood/fluid or a hyperdense mass containing small hematoma indicated intratumoral hemorrhage, and obscure hyperdensity indicated intratumoral hemorrhagic infarction. Such findings were often difficult to distinguish from spontaneous intracerebral hemorrhage due to other factors. The incidence of rebleeding from residual tumors was high, carrying a very poor prognosis, so radical removal of brain tumors with hemorrhage is very important.

Adolescent↗

PubMed1992

[MRI as an aid for diagnosis of infantile neuroaxonal dystrophy].

We experienced a 5-year-old girl, who had presented with nystagmus and psychomotor regression since 1 year old. No clinical diagnosis had been made despite various examinations including lysosomal enzymes and muscle biopsy. Her brain magnetic resonance imaging (MRI) revealed increased a T2 signal in bilateral cerebellar hemisphere. Recently this MRI finding was reported as a typical feature of infantile neuroaxonal dystrophy (INAD). Then we performed the second biopsy from her peripheral nerve, and diagnosed her as having INAD. It was suggested that MRI was a useful aid for the diagnosis of INAD.

Age Factors↗

PubMed1992

[A case of acute encephalopathy with symmetrical low density areas in the thalami on CT; serial CT and MRI findings].

A 5-year-old girl was admitted to our hospital because of fever, vomiting, diarrhea, convulsion and disturbance of consciousness. She was diagnosed as having acute encephalopathy, which is characterized by the symmetrical low density area in the thalami on CT. Serial MRI findings revealed the bleeding with edema in the thalami, and multifocal lesions with prolonged T1 and T2 relaxation time in the acute phase of the illness. Multifocal lesions were no longer found two months later. The sequential changes on the images about the bleeding in the thalami were not confirmed by simultaneous CT scans. The findings of the bleeding in the thalamic lesion are consistent with those of an autopsy report previously described and indicate the vascular involvement in the thalami in acute encephalopathy, which is characterized by the symmetrical thalamic lesions with the characteristic finding of low density on CT scans.

Acute Disease↗

PubMed1992

[Peripheral aneurysms of the posterior inferior cerebellar artery; analysis of 15 cases].

Peripheral aneurysms of the posterior inferior cerebellar artery (PICA) are rare. The authors report 15 cases of peripheral PICA aneurysms. Twelve of the aneurysms were discovered after their rupture and two were discovered after rupture of concomitant AVM, and one was detected incidentally. As to the location of aneurysms, more than half of the aneurysms arose at the telovelotonsillar segment. One patient had 2 aneurysms on the same peripheral PICA, which were not obvious on preoperative angiography because the ruptured one was partially thrombosed. Another rare case with aneurysm located at the internal auditory meatus is also reported. The findings of CT were characteristic, namely hemorrhage in the fourth ventricle without obvious hemorrhage in the basal cisterns, or only within the cerebellar vermian cistern. This phenomenon strongly suggested the possibility of rupture of peripheral PICA aneurysms. As to the surgical results, 10 patients (71%) of the 14 patients had a good recovery, and 1 patient (7%) with nonrupture aneurysm had a fair result due to pre-existing pontine hemorrhage. Three patients (21%) died. Rebleeding occurred in 3 patients, but cerebral vasospasm occurred in only 1 patient. Consequently, as peripheral PICA aneurysms are likely to be missed, and rebleeding is an unfavorable factor, one should try to demonstrate aneurysms with angiography, by using various methods such as subtraction or magnification.

Adolescent↗

PubMed1991

A possible correlation between the type of bcr-abl hybrid messenger RNA and platelet count in Philadelphia-positive chronic myelogenous leukemia.

The Philadelphia (Ph1) chromosome, in which the hybrid bcr-abl gene is formed, is thought to be the initial event in chronic myelogenous leukemia (CML). The position of the breakpoint within the breakpoint cluster region (bcr) on Ph1 chromosome and the splicing pattern determine the species of the fused bcr-abl messenger RNA (mRNA). We tried to detect the two types of fused mRNAs in 57 chronic-phase cases of Ph1-positive CML using the polymerase chain reaction procedure (RT-PCR). The bcr exon 2/abl exon 2 fused mRNA (b2-a2) was detected in 17 patients, the bcr exon 3/abl exon 2 fused mRNA (b3-a2) was detected in 34 patients, and both types of mRNA were detected in six patients. The platelet counts of patients who expressed b3-a2 mRNA or both types were significantly higher than those of patients who expressed only b2-a2 (841.5 v 373.5 x 10(9)/L; P less than .015), although there was no significant difference in the white blood cell counts or hemoglobin. This finding suggests a possibility that the type of bcr-abl mRNA may affect the thrombopoietic activity in CML.

Base Sequence↗

PubMed1991

Purification of recombinant human tumor necrosis factor precursor from Escherichia coli.

To study its biological functions, tumor necrosis factor precursor (proTNF) with a molecular size of 26-KDa was obtained as a recombinant protein from Escherichia coli. The recombinant proTNF was successfully accumulated in the insoluble form, corresponding to about 10-15% of total E. coli proteins. Solubilization, gel filtration and anion exchange chromatography were performed under denatured conditions followed by dialysis in phosphate-buffered saline. These processes removed most of the contaminating bacterial proteins, yielding proTNF with a purity of about 70-80%. This recombinant proTNF is expected to be useful for functional studies on activated macrophages with membrane integrated proTNF.

Blotting, Western↗

PubMed1991

[Experimental study of endoesophageal and intestinal expandable metallic stent placement].

Gianturco expandable metallic stents were implanted into the esophagus and small intestine of 10 rabbits in order to evaluate the influence of wire stents on the gastrointestinal tract. The stents were constructed of 0.010 inch stainless steel wire. The relaxed diameter of the stents was 12-14 mm and the length was 10 mm. Except for one stent placed in the small intestine, the stents did not migrate and were covered with thickening mucosal epithelium. The mucosal inflammatory changes were slight, but severe intestinal adhesions were noted. The findings in the two groups were not significantly different at three and six weeks. Five rabbits died within three weeks of intestinal disorders caused by severe intestinal adhesions and/or perforations. The experimental data showed that implantation of metallic wire stents into the gastrointestinal tract resulted in severe damage to the esophagus and small intestine of rabbits.

Animals↗

PubMed1991

Sequence and expression of a metabotropic glutamate receptor.

The complementary DNA of a metabotropic glutamate receptor coupled to inositol phosphate/Ca2+ signal transduction has been cloned and characterized. This receptor shows no sequence similarity to conventional G protein-coupled receptors and has a unique structure with large hydrophilic sequences at both sides of seven putative membrane-spanning domains. Abundant expression of this messenger RNA is observed in neuronal cells in hippocampal dentate gyrus and CA2-3 and in cerebellar Purkinje cells, suggesting the importance of this receptor in specific hippocampal and cerebellar functions.

Amino Acid Sequence↗

PubMed1991

[Self-expandable metallic stent for use in arterial occlusive lesions].

Gianturco expandable metallic stents were successfully placed in 4 patients with arterial occlusive disease: aortic obstruction or stenosis due to aortitis (n = 2), dissecting aneurysm (n = 1) and arteriosclerotic obstruction of the iliac artery (n = 1). The length of lesion was from 2 to 15 cm. In one case of aortitis (case 1), eleven stents (5 and 6 stents in tandem connected by wire struts) were inserted through a 12 F Teflon sheath. In another aortitis case (case 2) 4 stents in tandem were inserted through a 10 F sheath. In the two cases the sheaths were introduced by femoral arteriotomy. In case 3 and 4 two or four stents in tandem were placed through a 8 F long sheath which was introduced via the femoral artery by Seldinger method. Symptoms disappeared after placement of stents in all four cases. Our results showed the usefulness of expandable metallic stents in the treatment of arterial occlusive diseases.

Adult↗

PubMed1991

Magnetic resonance imaging in familial central diabetes insipidus.

More detailed examinations of the pituitary gland in central diabetes insipidus (CDI) has been possible with magnetic resonance imaging (MRI). Compared to the high signal findings in the posterior lobes of normal subjects, the absence of such signal in adults and children with primary CDI has been reported. Familial CDI is a hereditary form of primary CDI with a variety of clinical expressions among affected individuals which is said to be related to varying degrees of an arginine vasopressin (AVP) deficiency. However, the structural correlates have yet to be documented by MRI technique. This report describes the pituitary gland MRI findings (using a superconducting magnet; 3 mm-slice thickness; spinecho, repetition time 400 ms, echo time 25 ms) in five patients in one family with familial CDI. A signal of high intensity was detected in the posterior part of the pituitary gland in 2 patients but not in 3 others. We concluded that MRI of the posterior pituitary lobe in familial CDI seem to vary in members of the same family.

Child, Preschool↗

PubMed1991

Surgical treatment of cavernous angioma involving the brainstem and review of the literature.

Five cases of symptomatic cavernous angioma involving the brainstem are reported. Magnetic resonance (MR) imaging is of greatest value in the diagnosis and for surgical indication. All cases were treated by radical extirpation. All of them improved postoperatively. The surgical indications for this lesion of the brainstem are briefly discussed with a review of the literature, including 28 previous cases, operated on directly.

Adolescent↗

PubMed1991

Comparison of in vivo biological activities of luteinizing hormone releasing hormone (LHRH) analogues in 60-day-old cockerels.

The in vivo biological activities of various luteinizing hormone releasing hormone (LHRH) analogues in immature 60-day-old cockerels were compared, based on their capacity to increase circulating luteinizing hormone (LH) concentrations. Intravenous injections of 50, 100, or 500 ng of [Gln8]LHRH (cGnRH-I) and [His5,Trp7,Tyr8]LHRH(cGnRH-II) induced significant increases in the plasma LH level. The maximum response was always observed 2 min after the injection. Mammalian LHRH(mGnRH) significantly increased plasma LH, but only at the 500 ng dosage level. [Ile8]LHRH, [D-Ala6]LHRH, [Ala4]LHRH, [Leu8]LHRH, and [Phe5]LHRH increased plasma LH at 50-500 ng. [Ile7]LHRH, [Phe3]LHRH, and [Phe2]LHRH did not significantly increase plasma LH. Relative in vivo biological activities, calculated from dose (30-100 ng)-response curves of mGnRH-I, cGnRH-I, cGnRH-II, [Ile8]LHRH, [D-Ala6]LHRH, [Ala4]LHRH, [Leu8]LHRH, [Ile5]LHRH, [Ile7]LHRH, [Phe3]LHRH, and [Phe2]LHRH were 1.00, 1.40, 1.81, 1.50, 4.59, 1.90, 1.28, 1.56, 0.57, 0.67, and 0.57, respectively. These results demonstrate that avian LHRHs have higher biological activities than mammalian LHRH in the chicken. Furthermore, cGnRH-II is more potent than cGnRH-I, and [D-Ala6]LHRH has a very high activity while [Ile7]LHRH and [Phe2]LHRH have very low activities.

Animals↗

PubMed1991

The relationship between the site of breakpoints within the bcr gene and thrombopoiesis of Philadelphia-positive chronic myelocytic leukemia.

We determined the position of the breakpoint within the bcr gene in 22 patients with Philadelphia-positive chronic myelocytic leukemia using conventional Southern-blots and analyzed its relationship to thrombopoiesis. After DNA digestion with restriction endonucleases (Hind III, Bam HI and Bgl II), we localized the breakpoint in bcr using two genomic probes. The location of the breakpoint within the bcr was assigned to one of five zones. Breakpoints in zones 1 and 2 were grouped as "5"', and those in zones 3, 4 and 5 as "3'". Thus we subdivided patients with bcr rearrangements into those with genomic breaks at either 5' or 3' of the Bam HI site, just upstream of exon 3. Nine patients had 5' breakpoints and 13 patients had 3' breakpoints. The platelet counts of 3' patients were significantly higher than those of 5' patients (1395 vs 274 x 10(9)/l; p less than 0.03). The megakaryocyte counts from bone marrow histological sections in 3' patients (n = 12) and 5' patients (n = 7) were 63.4/mm2 and 19.5/mm2, respectively, with a significant difference of p less than 0.006. The mean number of megakaryocyte progenitor cells assayed by in vitro cloning was 128.3/2 x 10(5) bone marrow cells for 3' patients (n = 7) compared with 46.3 for 5' patients (n = 4). These results suggest that Philadelphia-positive CML patients with 3' breakpoints have higher thrombopoietic activity than patients with 5' breakpoints.

Adult↗

PubMed1991

In vitro studies on steroidogenesis in the presence of pregnenolone as precursors by the follicular tissue of the domestic fowl (Gallus domesticus).

Chicken granulosa and theca cells were isolated from F1 and F4-6 follicles 2-4 h before ovulation, and the amounts of progesterone, testosterone and oestradiol released in the medium during incubation for 3 h, in the presence or absence of pregnenolone as a percursor and stimulatory drugs or inhibitory drugs, were measured. Progesterone synthesis by granulosa cells was stimulated with oLH or theophylline. Much more progesterone was synthesized when pregnenolone was added to the medium. The amount of testosterone produced by the granulosa cells was similar to that produced by the theca cells. The production of testosterone was increased by the addition of oLH or theophylline. Oestradiol synthesis by F4-6 follicles was higher than by F1 follicles, and it was higher in the theca cells than in the granulosa cells. The addition of oLH or theophylline increased oestradiol synthesis in the theca cells and the granulosa cells of F4-6 follicles. The results indicate that oestradiol can be produced from pregnenolone by the theca cells alone. It is possible, however, that the theca cells also take in the precursors for the production of oestradiol from the granulosa cells.

Animals↗