Biomedical subjects

T Okubo

Publications and source records attributed to T Okubo.

At least 73 records · Page 4Linked to original sources

PubMed2000

Effect of human granulocyte-macrophage colony stimulating factor (hGM-CSF) on lymphoid and myeloid differentiation of sorted hematopoietic stem cells from hGM-CSF receptor gene transgenic mice.

Bone marrow lineage-negative (Lin(-)) c-Kit(+) Sca-1(+) hematopoietic cells from human GM-CSF receptor gene transgenic mice were cultured on established bone marrow stromal cell (TBR59) layers and on semisolid medium. In the semisolid assay, an increasing number of larger colonies were observed in the presence of hGM-CSF. By coculture with the stromal cells, cobblestones containing myeloid and lymphoid lineages of cells were formed from the stem cell enriched fraction, and addition of hGM-CSF strongly stimulated formation of the cobblestones containing both lineages. Repeating passages of the cobblestones on TBR59 stromal cells in the presence of hGM-CSF gradually decreased cobblestone formation and inversely increased macrophages and granulocytes, while mast cells were generated when the cells derived from the semisolid assay were cultured in a liquid medium containing hGM-CSF. These results consistently suggest that cytokines such as GM-CSF may costimulate the immature hematopoietic cells at their stroma-dependent phase before lineage commitment, and after commitment that occurs by an intrinsic program of the cells, they may stimulate maintenance and maturation of progenitor cells.

Animals↗

PubMed2000

Temporal changes of the apparent diffusion coefficients of water and metabolites in rats with hemispheric infarction: experimental study of transhemispheric diaschisis in the contralateral hemisphere at 7 tesla.

The purpose of the present study was to clarify the temporal changes of the apparent diffusion coefficients (ADCs) of cerebral metabolites during early focal ischemia using stimulated echo acquisition mode with short echo time at a 7 T magnet to assess the pathophysiology of the reduction in diffusion properties observed both in the ischemic cerebral hemisphere and in the contralateral hemisphere. The ADCs of metabolites in the infarcted hemisphere 1 hour and 3 hours after the onset of ischemia decreased with 25% and 29% for choline containing compounds (Cho), 16% and 26% for creatine and phosphocreatine (Cre), and 19% and 19% for N-acetylaspartate (NAA), respectively, compared with the ADC values 2 hours later in the contralateral hemisphere. There were decreases in the ADC of Cho, Cre, and NAA with 21%, 7%, and 18% 8 hours later, respectively, in the noninfarcted hemisphere, which suggested transhemispheric diaschisis in rats with focal cerebral ischemia. The present study proposed that the diffusion characteristics of the brain metabolites might offer new insights into circulatory and metabolic alteration in the cerebral intracellular circumstance.

Animals↗

PubMed2000

[Two cases of HIV infection accompanied with borderline personality disorder].

We report here two cases of HIV infection with a borderline personality disorder. Case 1 was a 25-year-old male patient who was diagnosed with HIV infection 4 years ago. Borderline personality disorder was also diagnosed at that time. Although he was referred to our hospital in 1999, we had to refer him to another hospital for his regular outpatient hemodialysis. Case 2 was a 24-year-old male patient who had borderline personality disorder since 1996. He was diagnosed with HIV infection in 1999 and referred to our hospital. He ignored rules in visiting clinics such as prior reservations and frequently called doctors, case-workers and nurses. After several visit he intentionally took excessive sedative medicines and called a case-workers at our hospital. He was admitted to our hospital for three days. After he was discharged, we set limitations for his behavior not to harm himself and to obey the rules in visiting clinics. In other countries investigators report that borderline personality disorder is more common in HIV-infected persons. It may be because persons with borderline personality disorder are more likely to engage in high-risk sexual behavior, which is also applicable to these two cases. As HIV infection is rapidly prevailing in Japan, it is possible that the chance are that this disorder will be seen more frequently in HIV infected cases.

Adult↗

PubMed2000

Detection of carbapenemase-producing Acinetobacter baumannii in a hospital.

Acinetobacter baumannii strains resistant to both imipenem (IPM) and ceftazidime (CAZ) were isolated from 1994 through 1996 at Gunma University Hospital. Nine isolates from different inpatients were examined for carbapenem-hydrolyzing activity and for the carbapemase gene bla(IMP) by the PCR method. All nine isolates were carbapenemase-producing strains that hydrolyzed IPM and that harbored bla(IMP). The bla(IMP) gene was transmissible by conjugation to an IPM-susceptible recipient strain of A. baumannii and conferred resistance to IPM, CAZ, cefotaxime (CTX), ampicillin (AMP), and piperacillin (PIP). Either intermediate or high-level resistance to amikacin (AMK) was transferred from two and five strains, respectively, concomitantly with bla(IMP), and gentamicin (GEN) resistance was also transferred in one instance of high-level AMK resistance. Comparative examination of clinical isolates for resistance patterns to nine drugs, IPM, CAZ, CTX, aztreonam, AMP, PIP, AMK, GEN, and norfloxacin, in addition to pulsed-field gel electrophoresis patterns with NotI-digested genomic DNA, confirmed nosocomial transmission of infections involving carbapenemase-producing A. baumannii strains.

Acinetobacter↗

PubMed2000

Regulation of aromatase expression in human ovarian surface epithelial cells.

Ovarian cancer originates mainly from surface epithelial cells, which are potential targets of estrogen action. Using immunohistochemistry and RT-PCR analysis, aromatase (estrogen synthetase) can be detected in human ovarian surface epithelial tumors. In this study, we functionally characterized the aromatase expressed in a primary cell culture, normal human ovarian surface epithelial (HOSE) 17. The apparent K(m) and V(max) values were determined to be 5.8 +/- 0.5 nM, and 0.3 +/- 0.0 pmol/mg.h, respectively. The aromatase activity in HOSE 17 cells can be induced effectively by phorbol esters and forskolin, suggesting that estrogen biosynthesis in HOSE 17 cells is mainly regulated through protein kinase C- and protein kinase A-mediated mechanisms. Exon I-specific RT-PCR revealed that phorbol esters predominantly up-regulated promoter II. Whereas forskolin treatment increased exon I.3A-containing messenger RNA, the aromatase activity remained low in the cells treated with this agent. In vitro transcription/translation analysis using plasmids containing T7 promoter and the human snail gene (SnaH) as a reporter capped with different untranslated exon Is revealed that exon PII-containing transcripts were translated more effectively than exon I. 3-containing transcripts. These findings explain why aromatase activity is higher in cells with the PII-containing transcripts than is cells with the I.3-containing transcripts. Our results indicate that aromatase is functionally expressed in human ovarian surface epithelial cells and its expression is regulated at both the transcriptional and translational levels.

5' Untranslated Regions↗

PubMed2000

Stroma-dependent maintenance of cytokine responsive hematopoietic progenitor cells derived from long-term bone marrow culture.

Hematopoietic cells maintained for long periods on primary cultures of bone marrow stromal cells formed cobblestone colonies (Dexter's long-term bone marrow culture, LTBC). These stably maintained hematopoietic cells (for 4 months) were transferred to a coculture on an established spleen stromal cell line (MSS62), and maintained under stromal cell layer, where they retained their invasive ability in the restricted space between the stromal cell layer and culture substratum (DFC culture). DFC contained lineage-negative (Lin-), c-Kit+, Sca-1- cells and spontaneously produced Mac-1+, Gr-1+ cells. DFC could not grow in the absence of MSS62 stromal cells, although, GM-CSF, IL-3, or IL-7 stimulated its growth. Production of granulocyte and monocytic cells was maintained by GM-CSF or IL-3 while it was decreased by IL-7. RT-PCR analysis showed that the IL-7 responsive cell population expressed early lymphoid markers (Ikaros, Pax-5, Oct-2, Rag-1, TdT, IL-7R and Imu), while lacking expression of receptors for G-CSF (G-CSFR) and for M-CSF (M-CSFR), or myeloperoxidase (MPO). These results suggested that DFC simultaneously contained lymphoid-committed progenitors and myeloid-committed progenitors, and that cytokines may expand their responding progenitor cells under the influence of signals provided by the stromal cells. Such a stromal cell-dependent culture system may be useful to analyze the switching mechanism from constitutive to inducible hematopoiesis in vitro.

Animals↗

PubMed2000

The inhibition of phenylhydroquinone-induced oxidative DNA cleavage by constituents of Moutan Cortex and Paeoniae Radix.

Moutan Cortex (root cortex of Paeonia suffruticosa ANDREWS) and Paeoniae Radix (root of Paeonia lactiflora PALLAS) are crude drugs used in many traditional prescriptions and have constituents in common. We studied the effects of extracts of these crude drugs and their constituents on oxidative DNA damage caused by phenylhydroquinone (PHQ), a major metabolite of o-phenylphenol. Both drugs suppressed the cleavage of pUC18 DNA induced by PHQ, and scavenged the superoxide and hydroxy radical generated by the chemical. They also inhibited the oxidative DNA cleavage by tert-butylhydroquinone (TBHQ), one of the major metabolites of butylated hydroxyanisole. When constituents were examined with the same system, galloylpaeoniflorin and 1,2,3,4,6-penta-O-galloyl-beta-D-glucose (PGG) were found to be the most potent inhibitors of the DNA cleavage. These constituents had oxygen radical scavenging activity. Paeonol also attenuated the DNA cleavage. Paeoniflorin and albiflorin had relatively small inhibitory effects on DNA cleavage. However, catechin enhanced the PHQ-induced DNA cleavage. The suppression of oxidative DNA damage by Moutan Cortex and Paeoniae Radix might be attributable to the additive effects of galloylpaeoniflorin, PGG and other constituents.

Biphenyl Compounds↗

PubMed2000

Surgical treatment of coarctation complex in neonates and infants.

BACKGROUND: There remains controversy regarding the appropriate surgical treatment of coarctation of the aorta associated with intracardiac anomalies in neonates and infants. Furthermore, the relative benefits of one versus two-stage repair, and subclavian flap aortoplasty versus end-to-end anastomosis for some of these lesions, remain controversial. The purpose of this paper is to review our experience with two-stage repair using subclavian flap aortoplasty and to seek an appropriate procedure. METHODS AND RESULT: From June 1996 to November 1999, thirteen patients underwent subclavian flap aortoplasty in our department. The age range was 16 to 101 days (mean 52 days), and the body weight range was 1.9 to 4.5 kg (mean 3.0 kg). Anatomic diagnosis was coarctation with ventricular septal defect (six patients), double outlet right ventricle (two patients), atrioventricular canal defect (one patient), tricuspid atresia (two patients), mitral atresia (one patient), and single atrium and subaortic stenosis (one patient). There was one hospital death in our series due to the progression of pulmonary hypertension 3 months after the operation. The mean follow up for remaining twelve patients was 28 months (range 7 approximately 48 months). There was one reoperation for recurrent coarctation. Three patients underwent pulmonary artery plasty in a second operation because of right pulmonary artery stenosis. We performed the definitive operation for six patients with coarctation with ventricular septal defect and two patients with double outlet right ventricle, and we performed a bidirectional cavopulmonary shunt for four univentricular hearts who are candidates for the Fontan operation. Two patients required Damus-Kaye-Stansel procedure to release restrictive bulboventricular foramen. Three patients underwent a modified Fontan operation after these palliations. In our series, the intraoperative mortality rate for subclavian flap aortoplasty was 0% and the post operative mortality rate was 7.7% (1/13). Ten patients underwent the final operation successfully, and further two patients are considered good candidates for the final operation. The overall mortality was 7.7% (1/13). CONCLUSION: Two-stage repair appears to offer a good prognosis for neonates and infants with a coarctation complex. Subclavian flap aortoplasty showed the lowest rate of restenosis. However, late mortality may be associated with the progression of pulmonary vascular disease and the presence of associated severe cardiac anomalies. Although Fontan candidates need staged operations, if biventricular repair is feasible, one-stage repair would be a reasonable procedure considering the progression of the pulmonary vascular disease and the distortion of the pulmonary artery due to pulmonary artery banding. It would appear to improve the quality of life of those children if a one-stage operation can be performed with reasonable risk and good midterm outcome.

Aorta↗

PubMed2000

Effect of estrogen and progesterone on gene expression of growth regulatory molecules and proto-oncogene in vascular smooth muscle cells.

We examined influences of estrogen and progestogen on gene expression of the growth regulatory molecules: platelet-derived growth factor (PDGF), interleukin-1 (IL-1), interleukin-6 (IL-6) and proto-oncogene c-myc in vascular smooth muscle cells (VSMC) by reverse transcription-polymerase chain reaction (RT-PCR) and Southern-blotting. VSMC were exposed to estrone-sulfate (E1-S) and medroxyprogesterone acetate (MPA) to induce differentiation. E1-S inhibited the expression of PDGF-A chain, IL-1, IL-6 and c-myc mRNA, whereas MPA had no effect. Inhibition by E1-S was not affected by treatment combined with MPA. These findings suggest that estrogen modulates these growth regulatory molecules and c-myc gene expression in VSMC but not progestogen. We concluded that estrogen may have a direct atheroprotective effect through inhibition of growth regulatory factors.

Arteriosclerosis↗

PubMed2000

[Impact of indirect factors on the growing prevalence of workers with abnormal findings in periodic general health examinations: a survey on the definition and detection of such abnormal workers by occupational health organizations].

The prevalence of workers with abnormal findings in periodic general health examinations (PGHEx) has been growing recently in Japan and reached 41.2% in 1998. To clarify the indirect factors related to such an increase in workers with abnormal findings in the PGHEx, we carried out a questionnaire survey on the content of the statutory notification form of results of the PGHEx among a representative sample of 136 Occupational Health Organizations (OHOs). Questions on how those workers with abnormal findings were defined and detected and when the definition and the reference intervals for total cholesterol became available were included. Of the 107 OHOs which answered the questionnaire, 85 were included in the analyses because they actually calculated the number of workers with abnormal findings in each company and helped the employer fill out the notification form. The results revealed that there was no standardized definition of workers with abnormal findings in the PGHEx. Both reference intervals of items in the PGHEx and algorithm in detecting workers with abnormal findings in the PGHEx varied among the OHOs. When detecting the workers, 13 OHOs (15.3%) selected them taking into consideration medical background factors such as previous results of the PGHEx and current medical treatment. From the late 1980s to the early 1990s, many OHOs modified the definition of workers with abnormal findings, and have tended to reduce the upper limit of the reference interval for serum cholesterol. This is mainly due to amendment of the Industrial Safety and Health Law and a new recommendation for a reference interval/value proposed by the related scientific society. Although the prevalence of workers with abnormal findings in the PGHEx has continuously increased, it is not valid to compare the prevalence over the years because of modification in the definition of such workers. The prevalence of workers with abnormal findings in the PGHEx, which is one of the most important indices of the state of occupational health, should be measured by using an objective definition and be compatible with the future system of health examination for Japanese workers.

Adult↗

PubMed2000

Internal carotid artery aneurysm visualized during successful endovascular treatment of carotid embolism.

We herein present a case of an internal carotid artery embolism associated with a hidden internal carotid artery aneurysm. The aneurysm was visualized during successful endovascular treatment of the carotid embolism. In retrospect, the aneurysm was at risk of rupture during the procedure. In the endovascular treatment of cerebral embolism, the possibility that aneurysms are hidden by emboli must be borne in mind. Care should be taken not to injure unidentified arterial walls while advancing a catheter blindly.

Aneurysm↗

PubMed2000

Genetic polymorphism of the CCK gene in patients with alcohol withdrawal symptoms.

BACKGROUND: Cholecystokinin (CCK) is considered to play an important role in the central nervous system via its interaction with other neurotransmitters such as dopamine, serotonin, gamma-aminobutyric acid, substance P, and enkephalins. We investigated the relationship between the C to T substitution in the Sp1 binding cis-element of the CCK gene promoter region (at position -45 numbered from initiation codon) and alcohol withdrawal symptoms. METHODS: We examined 214 Japanese men with alcoholism (93 with delirium tremens, 49 with hallucination, 38 with seizure, and 93 with none of these symptoms) and 98 age-matched Japanese male controls by using a polymerase chain reaction-based single strand conformational polymorphism analysis. RESULTS: Patients who displayed hallucination were significantly more likely to possess the C allele than control subjects (chi2 = 8.17, p = 0.017, Bonferroni correction: p = 0.064). In addition, we investigated the influence of CCK gene polymorphism on alcohol consumption among the control subjects but found no significant relationship. CONCLUSIONS: Our data suggested that the C allele at -45 locus of the CCK gene was higher in patients with hallucination than the control group at a rate that was not quite significant after Bonferroni correction for multiple testing.

Adult↗

PubMed2000

Severity of seropositive isolated Raynaud's phenomenon is associated with serological profile.

OBJECTIVE: To examine the relationship between the clinical severity of seropositive isolated Raynaud's phenomenon (RP) and its serological background by analyzing digital blood flow data obtained by laser Doppler flowmetry (LDF). METHODS: We analyzed digital blood flow by LDF in 13 healthy volunteers, 55 patients with seropositive isolated RP, and 13 patients with anti-Scl-70 antibody positive systemic sclerosis (SCL). The serological profiles of patients with RP were as follows: 30 patients had the anti-centromere antibody (C) and 19 the anti-RNP antibody (RNP). We designated the RP in each patient group as C-RP, RNP-RP, and SCL-RP. We used an "arm-raising test" by which blood pressure could be passively depressed, and the cold provocation test, which induced vasoconstriction through the sympathetic reflex. We defined 2 variables, the recovery velocity after cold exposure (RV-CE) and the increase in the amplitude of the digital pulse wave during the arm-raising test (IA-AR), that are the most reliable and sensitive variables indicating the severity of RP. RESULTS: Both RV-CE and IA-AR correlated significantly with the clinical severity of RP. In IA-AR and RV-CE, there was a significant difference between C-RP and RNP-RP (IA-AR 107.1 +/- 25.63 vs 37.4 +/- 17.25%; RV-CE 0.0667 +/- 0.010 vs 0.035 +/- 0.0096 V/s), showing that C-RP tended to be less severe than RNP-RP. CONCLUSION: We defined 2 variables that correlated with the clinical severity of RP; using them we found that anti-centromere antibody positive RP is less severe than RNP-RP

Arm↗

PubMed2000

[Assessment on intermittent intravenous cyclophosphamide pulse therapy in diffuse proliferative lupus nephritis].

OBJECTIVE: To determine whether intravenous cyclophosphamide pulse therapy (IVCY) is effective for treating patients with diffuse proliferative lupus nephritis (DPLN) who were 1) refractory to methylprednisolone pulse therapy (MP) or 2) could not be treated with MP because of severe diabetes or steroid induced psychosis. METHODS: Seven patients with biopsy proven DPLN were studied after informed consent. Five of them received IVCY after a failure to achieve renal remission with at least 2 cycles of MP therapy. Of the other 2 patients, one had severe diabetes and the other a history of steroid induced psychosis. Bolus therapy with cyclophosphamide (0.5 g/m2 body surface area) was given once a month for 6 consecutive months and then once every 3 months for a total treatment period of 1 year. All patients were given oral prednisone, 0.5 mg/kg per day. The prednisone dose was tapered to the minimal dose required for controlling the disease. After 1 year, the renal status of the patients were evaluated. RESULTS: At 1 year, 4 of the 7 patients achieved substantial improvement. Although the other 3 patients did not satisfy the definition of substantial improvement, none of them had progressive disease. Adverse events were mild and did not require any treatment, with 2 cases of leukocytopenia without fever or major infection. No cases of hemorrhagic cystitis or amenorrhea were observed. CONCLUSIONS: IVCY was 1) effective in the treatment of DPLN which was refractory to MP and 2) relatively safe with minimal side effects.

Adult↗

PubMed1999

Novel polymorphism in the promoter and coding regions of the human cholecystokinin B receptor gene: an association analysis with schizophrenia.

Genetic variations in the 5'-untranslated region and the coding region of the CCK-B receptor (CCK-BR) gene were investigated in healthy controls. Novel variants (-215 C-->A, Leu37Phe, Arg319Glu) were found in addition to the mutations (Val125Iso, His207His, Arg215His, 2491 C-->A) reported previously. In the present study, association analysis was carried out for these variants between 80 unrelated schizophrenic patients and 100 healthy controls. The genotype frequency of the -215 C-->A nucleotide substitution in the 5'-untranslated region of CCK-BR gene was significantly higher in the schizophrenic patients than in the controls (6.25%, P = 0.037). However, the difference was not significant after Bonferroni correction for multiple comparisons. Moreover, no association was found between the clinical characteristics of the patients and the genotype frequencies of the variants. These results suggest that the CCK-BR gene polymorphisms have no association with schizophrenia nor its clinical heterogeneity. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 88:700-704, 1999.

5' Untranslated Regions↗

PubMed1999

Epigallocatechin gallate and gallocatechin gallate in green tea catechins inhibit extracellular release of Vero toxin from enterohemorrhagic Escherichia coli O157:H7.

We studied the effects of six catechin derivatives (catechin, epigallocatechin, epicatechin, epicatechin gallate, epigallocatechin gallate (EGCg) and gallocatechin gallate (GCg)) in green tea on the production and extracellular release of Vero toxins (VTs) from enterohemorrhagic Escherichia coli (EHEC) cultured at 37 degrees C for 24 h. EGCg and GCg in the culture medium markedly inhibited extracellular VTs release from EHEC cells into the culture supernatant fluid at concentrations of 0.05 mg/ml or higher, as estimated by both the reversed passive latex agglutination assay and cytotoxic assay using Vero cells. Production and extracellular release of maltose binding protein, a periplasmic protein, into the culture supernatant were also inhibited by EGCg and GCg, indicating that their inhibitory effect on release from periplasm into the outer milieu is not specific to VTs, but general to the proteins accumulated in EHEC periplasm.

Bacterial Proteins↗

PubMed1999

Absorption of Polyelectrolytes on Colloidal Surfaces as Studied by Electrophoretic and Dynamic Light-Scattering Techniques.

zeta-Potential and the effective diameter of the colloidal spheres absorbed with the macro-cations and macro-anions are studied by the electrophoretic light-scattering and dynamic light-scattering measurements. Colloidal spheres used are monodispersed polystyrene (220 nm in diameter) and colloidal silica spheres (110 nm). Macro-ions used are sodium polyacrylate, sodium polymethylacrylate, sodium poly(styrene sulfonate), and poly-4-vinyl pyridines quaternized with ethyl bromide, n-butyl bromide, benzyl chloride, and 5% hexadecyl bromide and 95% benzyl chloride. Reversal of colloidal surface charges from negative to positive occurs abruptly above the critical concentration of macro-ions by the excess absorption of the macro-cations onto the anionic colloidal spheres, i.e., avalanche-type absorption. The effective diameter of colloidal spheres including the absorbed layers increases substantially by four- to tenfold. In the presence of large amount of macro-cations aggregation of colloidal spheres mediated by the layers of absorbed macro-cations may occur. Absorption also occurs on the anionic colloidal spheres in the presence of an excess amount of macro-anions by the dipole-dipole-type attractive interactions. Copyright 1999 Academic Press.

Journal Article↗

PubMed1999

Binding characteristics of [3H]DAA1106, a novel and selective ligand for peripheral benzodiazepine receptors.

Here, we investigated the binding characteristics of [3H]N-(2,5-dimethoxybenzyl)-N-(5-fluoro-2-phenoxyphenyl)acetamide ([3H]DAA1106), a potent and selective ligand for peripheral benzodiazepine receptors, in mitochondrial fractions of the rat brain. [3H]DAA1106 bound to the mitochondrial fraction of the rat brain in a saturable manner. The dissociation constant (Kd) and maximal number of binding sites (Bmax) obtained from Scatchard plot analysis of the saturation curve of [3H]DAA1106 binding were 0.12 +/- 0.03 nM and 161.03 +/- 5.80 fmol/mg protein, respectively. [3H]DAA1106 binding to mitochondrial preparations of the rat cerebral cortex was inhibited by several peripheral benzodiapine receptor ligands, and DAA1106 was the most potent inhibitor in inhibiting [3H]DAA1106 binding among the peripheral benzodiazepine receptor ligands we tested. The binding of [3H]DAA1106 was not affected by several neurotransmitter-related compounds, including adrenoceptor, gamma-aminobutyric acid (GABA), dopamine, 5-hydroxytryptamine (5-HT), acetylcholine, histamine, glutamate and central benzodiazepine receptor ligands even at a concentration of 10 microM. In the cerebral cortex of rhesus monkeys, DAA1106 and 1-(2-chlorophenyl)-N-methyl-(1-methylpropyl)-3-isoquinoline carboxamide (PK11195) potently inhibited [3H]DAA1106 binding, while 7-chloro-5-(4-chlorophenyl)-1-methyl-1,3-dihydrobenzo[e][1,4]diazepin -2-one (Ro5-4864) did not. The highest [3H]DAA1106 binding was observed in the olfactory bulb, followed by the cerebellum. In autoradiographic studies, practically the same results were obtained, in that the highest binding of [3H]DAA1106 was in the olfactory bulb. Potent labeling was also noted in ventricular structures such as the choroid plexus. Thus, [3H]DAA1106 is a potent and selective ligand for peripheral benzodiazepine receptors and should prove useful for elucidating the physiological relevance of events mediated through peripheral benzodiazepine receptors.

Acetamides↗