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Biomedical subjects

T Yazaki

Publications and source records attributed to T Yazaki.

At least 73 records · Page 4Linked to original sources
PubMed1993

Postexposure prophylaxis of varicella in family contact by oral acyclovir.

OBJECTIVE: To determine whether varicella can be prevented by administration of oral acyclovir (ACV) during the incubation period of the disease. SUBJECTS AND METHODS: ACV (40 or 80 mg/kg daily in four divided doses) was given orally to 25 exposed infants and children for 7 days, starting 7 to 9 days after exposure from the index case in their families. Their clinical features were compared with those of 25 age-matched control subjects who had been exposed in their families but did not receive ACV. A fluorescent antibody to membrane antigen assay was used for determination of the antibody to varicella-zoster virus, and a nested polymerase chain reaction method was used for detection of viremia. RESULTS: Among the 25 who received ACV, 4 (16%) developed the disease and 1 (4%) had a fever. On the other hand, all of 25 control subjects developed the disease and 17 (68%) had a fever. The incidence of fever and the severity of skin rashes were significantly lower (P < .01) in the subjects who received oral ACV than in the control group. Seroconversion was observed in 84% of subjects who received ACV. In some cases, varicella-zoster virus DNA was detected by polymerase chain reaction amplification in peripheral blood mononuclear cells from blood drawn approximately 14 days after exposure. CONCLUSIONS: Varicella can be prevented or modified by administration of oral ACV late in the incubation period.

Acyclovir↗
PubMed1992

Glycopeptide of P0 protein inhibits homophilic cell adhesion. Competition assay with transformants and peptides.

Expression of major myelin glycoprotein P0 by P0 cDNA transfection into C6 glioma cells promoted homophilic cell adhesion of the cells. After the dissociated cells were incubated for various times, the number of particles at each time point was measured. The total number of particles decreased to 24% in 60 min for transformant (C6P0) cells, in contrast to only 68% for control (C6P0') cells. To confirm the homophilic mechanism of adhesion, mixed-cell aggregation experiments were performed. Among the four synthetic peptides corresponding to a part of the P0 sequence used, only peptide 3 (residues 90-96), which contained a carbohydrate attaching site, caused considerable inhibition of cell aggregation (approximately 50%). In addition, the glycopeptide (residues 91-95) obtained from bovine P0 markedly inhibited cell aggregation (by approximately 85%).

Amino Acid Sequence↗
PubMed1992

Endonuclease analyses of DNA of human herpesvirus-6 isolated from blood before and after bone marrow transplantation.

Three strains of human herpesvirus-6 (HHV-6) were isolated from peripheral blood mononuclear cells of a leukemic child with the antibody of HHV-6 before and after bone marrow transplantation (BMT); two strains were obtained before BMT and one after BMT. The DNA extracted from the three isolates was analyzed by six different restriction endonucleases. The cleavage profiles of two strains obtained before BMT were different, but the third strain isolated after BMT was identical with one of the two, which suggest reactivation of HHV-6 from the recipient's own body after BMT and possible mutation or super-infection of the virus in an immunocompromised patient.

Bone Marrow Transplantation↗
PubMed1992

Activation of human herpesvirus-6 in children with acute measles.

Virological and serological studies were carried out prospectively to evaluate the possible activation of human herpesvirus-6 (HHV-6) in 50 infants and children with acute measles by isolation of HHV-6 from peripheral blood and by determining neutralizing antibodies to the virus. All but 5 patients (90%) were seropositive to HHV-6 in the acute stage of measles and 18 (40%) had a significant increase in HHV-6 antibody titers thereafter, whereas only 2 of 27 patients who were initially seropositive to Epstein-Barr virus (EBV) viral capsid antigen (VCA) had a significant rise in antibody titers to EBV VCA. Among 18 patients with a significant increase in HHV-6 titers, the virus was isolated from the peripheral blood mononuclear cells of three patients in the early convalescent stage of measles. These results indicate that activation of HHV-6 may occur frequently a few weeks after primary infection with the measles virus.

Acute Disease↗
PubMed1992

A prospective study of human herpesvirus-6 infection in renal transplantation.

Sixty-five kidney transplant recipients and their (22 living related and 43 cadaveric) donors were studied prospectively to determine the relationship between kidney transplantation and human herpesvirus-6 (HHV-6) infection. The virus isolation from peripheral blood and other tissues and sequential determination of neutralizing antibodies to HHV-6 were performed during 3 months following the transplantation. All of the donors and their recipients examined had neutralizing antibodies to HHV-6 at the time of renal transplantation and the virus was not isolated from them. HHV-6 was isolated from 3 renal tissues (2 living related and 1 cadaveric) obtained during transplant surgery, but not from their blood at that time. HHV-6 viremia occurred in 9 (14%) of the 65 recipients around 2 to 4 weeks after the transplantation. An additional 27 recipients showed a significant rise in the antibody titer. Thus, the infection with HHV-6 was confirmed in 36 (55%) of the 65. These results indicate that the virus is activated in many cases in the early posttransplant period and that HHV-6 establishes in vivo latency in the kidney tissue. There was no correlation between HHV-6 infection and acute rejection or the antirejection prophylaxis.

Adolescent↗
PubMed1992

IgM neutralizing antibody responses to human herpesvirus-6 in patients with exanthem subitum or organ transplantation.

The assay for detecting IgM neutralizing (NT) antibody activity to human herpesvirus-6 (HHV-6) was developed by using pretreatment of blood sample with staphylococcal protein A. The activity was mostly present in IgM fractions of serum but not in IgA fractions separated by ultracentrifugation. The assay was used for seroepidemiological studies for HHV-6 infection. In primary HHV-6 infection, IgM NT antibodies appeared 5 to 7 days after onset of exanthem subitum, reached maximum titers at 2 to 3 weeks, and tended to decline to undetectable levels after 2 months. In contrast, reactivation of HHV-6 observed in organ transplants showed somewhat greater degree of IgM NT antibody responses that persisted for 2 to 3 months and became undetectable 5 to 6 months after transplantation. The level and persistence of NT antibody titers measured by the conventional method was generally greater than those of the IgM titers. The prevalence of the IgM NT antibodies was examined in healthy individuals. The antibody was first detected at 4 to 7 months of age (5%), reached maximum level at 8 to 11 months (40%), and was detectable by 4 to 6 years (17%). A few (4 to 5%) of adolescents and adults were positive for the antibody.

Adolescent↗
PubMed1992

Comparison of severity of viremia and antibody responses between infants and children with measles.

Severity of viremia and neutralizing antibody responses were compared between nine young infants (less than or equal to 10 months) with measles and 18 infants and children (greater than or equal to 11 months) with ordinary measles. Peripheral blood mononuclear cell (PBMC)-associated viremia was detected between the first day of elevation of fever (day 0) and day 5 of the disease in the former group, whereas PBMC-associated and cell-free viremia were detected between day 0 and day 14 in the latter group. The number of infected PBMC during the first 7 days of the disease was 3.22 +/- 1.07 (log10, mean +/- s.d.) per 10 million PBMC in the former group, which was significantly smaller (P = 0.02) than that of the latter group (4.21 +/- 1.18). The former group reached the maximum level of antibody earlier than the latter group.

Age Factors↗
PubMed1992

Fatal encephalitis/encephalopathy in primary human herpesvirus-6 infection.

An encephalitic illness with a fatal outcome occurred in a 9 month old girl with virologically confirmed exanthem subitum. Human herpes-virus-6 (HHV-6) DNA was found in the cerebrospinal fluid at the acute stage of the disease by the polymerase chain reaction, but the virus antigen was not detected in her brain tissue. This suggests that HHV-6-induced encephalitis/encephalopathy may be due to a non-infectious process.

Antigens, Viral↗
PubMed1992

Percutaneous trigeminal rhizotomy and percutaneous cordotomy under general anesthesia.

Most percutaneous procedures for the treatment of pain are done under local anesthesia and considerable pain can be involved. If the patient is elderly or confused because of severe pain, it is difficult or impossible to perform these procedures successfully. We treated 3 elderly patients with trigeminal neuralgia and 1 patient with severe bone pain due to metastatic osteosarcoma in the lumbosacral region by percutaneous trigeminal rhizotomy and percutaneous cordotomy under general anesthesia with intratracheal intubation. We conclude that percutaneous trigeminal rhizotomy and percutaneous cordotomy can be safely done under general anesthesia.

Aged↗
PubMed1992

Human herpesvirus-6 DNA in cerebrospinal fluid of a child with exanthem subitum and meningoencephalitis.

The involvement of human herpesvirus-6 (HHV-6) and herpes simplex virus infections was evaluated virologically and serologically in a 13-month-old girl with meningoencephalitic illness occurring in the pre-eruptive stage of exanthem subitum. An isolation of HHV-6 from blood and seroconversion to the virus confirmed the primary infection with the virus. HHV-6 gene sequences were detected in cerebrospinal fluid of acute stage of the disease by polymerase chain reaction. There was no evidence of herpes simplex virus infection in blood and cerebrospinal fluid. The patient recovered from the disease without any sequelae, although abnormal electroencephalography and cerebral computed tomography findings were observed temporally in the acute stage of the disease. These findings strongly suggest that HHV-6 invades the central nervous system and causes meningoencephalitis.

Antibodies, Viral↗
PubMed1992

[Traumatic intracranial aneurysms after removal of tuberculum sellae meningioma: case report].

Two cases of traumatic aneurysms (TA) of the internal carotid artery (IC) due to removal of tuberculum sellae meningioma (TSM) are presented, and ideal treatment of those aneurysms is discussed. The tumor, compressing the IC laterally, was removed out without arterial injury in case 1. Though the patient's postoperative course was uneventful, frontal and intraventricular hemorrhage developed 2 months after the operation, and an IC dorsal aneurysm was detected. Preoperative angiograms showed no aneurysm, so it was considered to be a traumatic aneurysm due to the surgical procedure. The aneurysm was clipped at once, but postoperative angiograms showed recurrence of the aneurysm. IC balloon occlusion was carried out as the Matas test was negative. In case 2, a small tear in the IC was inadvertently made during recurrent TSM removal, which was wrapped with muscle using fibrin glue. 2 weeks after the operation, frontal hemorrhage developed. Angiograms revealed a small aneurysm of the IC, which was considered to be a traumatic aneurysm. IC balloon occlusion was performed as the Matas test was negative. These 2 patients have had no episodes of rerupture after the IC balloon occlusion. Tumors and main arteries are frequently adhesive, so arteries are easily injured during removal of meningiomas. Muscle wrapping was not enough to prevent TA formation. Neck clipping was not appropriate for treatment of TA, but IC balloon occlusion was an effective and excellent therapy for TA of IC.

Adult↗
PubMed1992

[Surgical exploration for renal cyst: two-case report].

A 59-year-old male was admitted to our clinic for further examination of the calcified renal cyst discovered incidentally on medical workup elsewhere. CT showed a left renal cyst associated with calcification. Ultrasound-guided puncture of the renal cyst was not successful because of thickness of the cystic wall. Renal angiography showed hypervascularity of the cystic wall. Association of renal cell carcinoma could not be ruled out, therefore the exploration was performed. Histological examination revealed benign renal cyst with calcification. A 27-year-old male presented with the chief complaint of left flank pain. Following examinations by US, CT and MRI, a renal cyst associated with renal cell carcinoma was highly suspected. Subsequent exploration revealed cluster of cysts with a yellowish lesion a few mm in diameter. Frozen section revealed no malignancy, and cystic fluid was not hemorrhagic. Therefore as many cystic walls as possible were removed without nephrectomy. Histological examination of the permanent specimen revealed renal cell carcinoma. Renal cyst associated with renal cell carcinoma was regarded as rare clinical entity, but such cases are reported in increasing number in recent years. We report such cases and review the pertinent literature in this paper.

Adult↗
PubMed1991

Recombinant human interleukin-1 beta analogue as a regulator of hematopoiesis in patients receiving chemotherapy for urogenital cancers.

Ten patients with advanced urologic cancers who were scheduled to receive at least two courses of chemotherapy were enrolled in this trial. Fifty thousand units of recombinant human interleukin-1 (IL-1) beta analogue OCT-43 (Otsuka Pharmaceutical Co., Ltd., Tokyo, Japan) was administered subcutaneously only once or twice when severe neutropenia (less than 500/microliters) continued for 2 consecutive days. In eight patients, OCT-43 was not injected in the first course of chemotherapy as a control, but was injected in the second course. The durations of leukocytopenia (less than 2000/microliters) and neutropenia (less than 1000/microliters) were significantly shortened in the second course compared with those in the first course in those eight patients. Recovery of neutrophil number from the lowest number was also significantly faster in the second course. Thus, OCT-43 was considered to have hematopoietic activities. However, single or double injection of OCT-43 did not affect the numbers of eosinophilic or basophilic granulocytes, monocytes, or platelets. Adverse effects associated with OCT-43 injections were high fever and chills, but they were controlled by indomethacin.

Adult↗
PubMed1991

Human herpesvirus-6 infection in bone marrow transplantation.

Twenty-five pediatric patients who received bone marrow transplantation (BMT) were studied prospectively to determine the relationship between BMT and human herpesvirus-6 (HHV-6) infection by the virus isolation from peripheral blood and/or bone marrow and by determining neutralizing antibodies to HHV-6 during the 2 months following BMT. All of the 25 donors and the recipients were immune to HHV-6 at the time of BMT and the virus was not isolated from them. HHV-6 was isolated from peripheral blood and/or bone marrow mononuclear cells in ten (40%) of the 25 recipients between day 14 and day 22 of BMT, but not from any other day. Two additional recipients showed a significant increase in the antibody titer. Thus, infection with HHV-6 was confirmed in 12 (48%) of the 25 recipients. Four of the 12 developed skin rashes; three of these four had a febrile episode when the virus was isolated, whereas none of the remaining 13 developed the skin rash. These results suggest a frequent infection with HHV-6 only a few weeks after BMT and a close association between the infection with the virus and the development of skin rashes.

Adolescent↗