Biomedical subjects

H Yokoyama

Publications and source records attributed to H Yokoyama.

At least 19 recordsLinked to original sources

PubMed1992

Opioid mu-deficient CXBK mouse and the role of mu 1-receptors in electrically induced convulsions.

Studies were made on the role of mu 1-receptors on electrically induced convulsions in mice. A relatively selective mu 1-agonist, DAGO ([D-Ala2-N-methyl-Phe4-Gly-ol]-enkephalin) decreased the durations of tonic and clonic convulsions in C57BL/6 mice, but not in opioid mu-deficient CXBK mice, indicating that the activation of mu 1-receptors had an anticonvulsive effect on these convulsions in mice. The selective mu 1-antagonists naloxonazine and naltrexonazine promoted the clonic phase of electrically induced convulsion in C57BL/6 mice. Moreover, the duration of the clonic phase was longer in mu-deficient CXBK mice than in C57BL/6 mice. These data for CXBK mice confirmed, at least some proconvulsant effects of mu 1-antagonists in C57BL/6 mice. Thus, blockade of mu 1-receptors has a proconvulsant effect, and mu 1-receptors have at least some protective role against electrically induced convulsions.

Animals↗

PubMed1992

ras gene mutations as a prognostic marker in adenocarcinoma of the human lung without lymph node metastasis.

Adenocarcinoma of the lung obtained at surgical resection was examined for mutation at codons 12, 13, and 61 of the oncogenes K-ras, H-ras, and N-ras, using polymerase chain reaction and oligonucleotide hybridization techniques. The mutation was detected in 18 of the 115 cases (15.7%), and 15 of 18 were at codon 12, 2 were at codon 13 of K-ras, and 1 was at codon 61 of N-ras. G to T transversions were most common. The ras gene mutations were more frequent in the male patients (P = 0.0048). No significant differences were found to be related to stage of the disease or tumor-nodes-metastases classification between positive and negative groups of the ras gene mutations. A history of tobacco use was not always a factor contributing to mutation. Of the completely resected group without lymph node metastasis, the 5-year survival rate in the ras-positive group was 53.3%, which was significantly poorer than the 83.6% survival rate in the ras-negative group (P less than 0.05). Our findings suggest that ras gene mutations may be prognostic, especially in the early stage adenocarcinoma of the lung.

Adenocarcinoma↗

PubMed1992

Histamine H1 receptors in human brain visualized in vivo by [11C]doxepin and positron emission tomography.

Histamine H1 receptors in the living human brain were visualized by positron emission tomography (PET) using [N-11C-methyl]-(E)-doxepin ([11C]doxepin). The regional distribution of the carbon-11-labeled compound in the brain corresponded well with that of the histamine H1 receptors measured in vitro using [3H]pyrilamine. The radioactivity in the brain was significantly reduced by intravenous pretreatment with d-chlorpheniramine (5 mg), a histamine H1 antagonist. The regional distribution of [11C]doxepin in the brain 45-90 min after its injection was almost the same as that of [11C]pyrilamine in the brain. These results indicate that [11C]doxepin is useful for measuring histamine H1 receptors in human brain by PET.

Adult↗

PubMed1992

Anticonvulsant effect of liposome-entrapped superoxide dismutase in amygdaloid-kindled rats.

Amygdaloid-kindled rats received intravenous human copper-zinc superoxide dismutase (CuZn-SOD) either in free form or entrapped within liposomes (SOD-L), at 5, 10 or 20 mg/kg. The animals were stimulated at the generalized seizure-triggering threshold 5 min, 2 h and then every 24 h after the drug was given, until 5 consecutive stage 5 seizures were induced. Free CuZn-SOD had little or no effect. However, SOD-L, particularly at 10 mg/kg, had a prolonged anticonvulsant effect, although there was great individual variation in the onset and duration of seizure suppression. This effect of SOD-L may be due to the ability of liposomes to act as a depot for the sustained release of drugs.

Amygdala↗

PubMed1992

Histamine levels and clonic convulsions of electrically-induced seizure in mice: the effects of alpha-fluoromethylhistidine and metoprine.

The purpose of this study was to investigate the possible role of the central histaminergic neuron system in electrically-induced seizure in mice. For this purpose, we examined the effects of intraperitoneal (i.p.) injections of histaminergic agents, such as L-histidine, metoprine, and alpha-fluoromethylhistidine (FMH), on electrically-induced seizure. L-Histidine decreased the duration of clonic convulsion in electrically-induced seizure, but not affected that of tonic convulsion. This effect of L-histidine was antagonized by pretreatment with FMH, indicating that it was due to histamine formed by decarboxylation of L-histidine in the central nervous system. The anticonvulsive effect of L-histidine was also reduced by the H1-antagonist pyrilamine, but not by the H2-antagonist zolantidine, indicating that the effect on electrically-induced seizure is mediated through central H1-receptors. Metoprine, which increased the histamine levels in the cerebral cortex, diencephalon and midbrain of mice, decreased the duration of clonic convulsions dose-dependently. Conversely, FMH, which decreased the brain histamine levels, increased the duration of clonic convulsions. Good inverse correlations were found between the duration of clonic convulsions and brain histamine levels, especially in the diencephalon: the histamine levels were inversely proportional to the duration of clonic convulsions. No correlation was found between the duration of tonic convulsions and brain histamine levels. These results suggest that the histaminergic neuron system is important in inhibition of the duration of clonic convulsion on electrically induced seizure in mice.

Animals↗

PubMed1992

Predominant beta-adrenoceptor blocking effect of xamoterol averaged over the day in patients with mild to moderate heart failure: insight into the mechanism of its long-term clinical efficacy.

Xamoterol acts as a beta 1-adrenoceptor agonist at low sympathetic activity and as an antagonist at high activity. Although its long-term efficacy has been proven in patients with mild to moderate heart failure, it remains unclear which effect, agonism or antagonism, accounts for its long-term activity. To clarify the effect of xamoterol on cardiac sympathetic activity in daily life, 24-h R-R interval histograms were obtained during administration of xamoterol 100 mg b.d. for 1 week to 10 patients with mild to moderate heart failure. Eight normal subjects were also studied as controls. To examine the relation between the effect of xamoterol and sympathetic activity, plasma noradrenaline (NA) levels were measured under 5 graded conditions simulating daily living. Xamoterol administration significantly decreased the standard deviation of the R-R interval, both in patients with heart failure and in normal subjects. The mean R-R interval, however, was increased in patients with heart failure, relative to normal subjects. In both groups, the R-R interval histograms had two peaks, i.e. a short daytime peak and a long night-time peak. Xamoterol decreased the median of the night-time peak without changing the daytime peak in normal subjects. In contrast, it increased the median of the daytime peak without producing a significant change in the night-time peak in patients with heart failure. Levels of plasma NA were significantly higher in patients than in normal subjects under all conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗

PubMed1992

Human insulin-specific immunoglobulin G antibody and hypoglycemic attacks after the injection of gold thioglucose.

A 56-year-old woman with granulomas of gold thioglucose in her hips exhibited recurrent bouts of hypoglycemic attacks. The first attack occurred 2 years after the last injection of gold thioglucose, when large amounts of extractable insulin and human insulin-specific antibody were noted in her serum. Histological examination of the resected granulomas showed marked infiltration of lymphocytes, plasma cells, and macrophages containing yellowish-brown granules, which proved to be gold by electron microscopy using X-ray microanalysis. After resection of the granuloma, however, the frequency of the hypoglycemic attacks decreased remarkably as well as the levels of both extractable insulin and human insulin-specific antibody.

Antibody Specificity↗

PubMed1992

Surgically resected lung cancer in young adults.

Twenty-two patients, 40 years old or younger, were surgically treated for lung cancer between 1974 and 1989. The male to female ratio was 1.2:1. Ten patients were symptomatic, with the average duration of symptoms being 3.6 months. There were 13 patients with adenocarcinoma and 9 patients with large cell carcinoma. In terms, of postoperative stages, 5 patients were classified in stage I, 10 in stage IIIa, 5 in stage IIIb, and 2 in stage IV. Complete resection was performed in 14 patients, incomplete resection in 6, and exploratory thoracotomy in 2. The 3-year survival rate after complete resection was 66.2% in young patients, which was not significantly different from the 65.2% 3-year survival rate in older patients. There was no significant difference between the young and older groups according to histological cell type and TNM staging. In cases of incomplete resection or exploratory thoracotomy, 4 of 8 patients had been alive more than 2 years after operation. These results suggest that a long-term survival in the young patients is expected to be almost the same as that in the older patients after either complete resection or incomplete resection.

Adenocarcinoma↗

PubMed1992

Sclerosing hemangioma of the lung: radiographic and pathological study.

The clinical, radiographic, and pathological features of 10 patients with sclerosing hemangioma of the lung seen between 1974 and 1990 were reviewed. The incidence of sclerosing hemangioma was 22.2% of benign tumors surgically resected during that time. There were 2 male and 8 female patients aged 15 to 77 years at operation, and 9 patients were asymptomatic. All 10 patients had a solitary tumor with a well-defined homogeneous round or oval shadow on chest roentgenograms. Chest computed tomography revealed a homogeneous soft-density mass in 4 patients and a low-density portion within the tumor because of a cystic change in 1 patient. Microscopically, 5 patients had a preponderantly solid pattern, 3 had a preponderantly papillary pattern, and 1 patient had a preponderantly sclerotic pattern. One patient had an equal mixture of solid and papillary patterns. Nine of the 10 tumors consisted of a mixture of at least three of the four major patterns. Regarding treatment, thoracotomy is indicated for a definite diagnosis. If a benign tumor is suspected at operation, an intraoperative frozen section is recommended. Once the diagnosis has been established as sclerosing hemangioma, a limited resection is indicated.

Adolescent↗

PubMed1992

An ESR-CT imaging of the head of a living rat receiving an administration of a nitroxide radical.

Three-dimensional ESR imaging of a living rat has been performed by an L-band ESR system, which is composed of an L-band ESR spectrometer, a field gradient coil, and a data processor. The imaging was carried out by Lauterbur's method. A nitroxide, 3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl (Carbamoyl-PROXYL), was used as an imaging agent in saline solution at a concentration of 0.2 M and administered intraperitoneally to obtain a constant concentration in the head for about an hour. It took about 40 min to obtain one set of ESR-CT images. The cross-sectional images were made, both as coronal and horizontal images. In the images of the rat head the nitroxide-rich region was clearly distinguished from the deficient region. The nitroxide-deficient areas corresponded well to the brain of the rat.

Animals↗

PubMed1992

Pulmonary tuberculoma and indications for surgery: radiographic and clinicopathological analysis.

Tuberculomas of the lung are one of the more common lesions presenting a solitary pulmonary nodule, roentgenographically. We treated 36 patients with such nodules and describe here the radiologic-pathologic correlations and surgical treatment. In 21 patients, lung cancer was suspected preoperatively, based on radiographic findings of an ill-defined margin, pleural indentation and spicular radiation. Histologically, the tuberculous granuloma proliferated in the alveolar septa of the surrounding normal lung, often seen as a spicular radiation resembling lung cancer. In eight patients, tuberculoma was suspected because of radiographic findings of calcification and satellite nodules, and anti-tuberculous chemotherapy was prescribed for a few months. As this treatment was ineffective, surgical resection had to be done. Postoperative complications were nil and all of these patients are doing well at the time of preparation of this report. Anti-tuberculous chemotherapy was prescribed for 28 of 36 patients, postoperatively. We believe that surgical intervention is required for selected patients.

Adult↗

PubMed1992

Up-regulated MHC-class II expression and gamma-IFN and soluble IL-2R in lupus nephritis.

Expression of MHC-class II molecules (HLA-DR and -DQ), serum gamma-interferon (gamma-IFN) and soluble interleukin-2 receptor (sIL-2R) levels were studied in 35 Japanese patients with lupus nephritis (LN) to clarify intraglomerular cellular activation and cytokine involvement in human LN. In 11 normal kidney specimens, HLA-DR(Ia1) was noted in glomerular tufts, but HLA-DQ was either not or was faintly detected in glomeruli by the indirect immunofluorescence technique. HLA-DR and -DQ were observed mainly on the surface of glomerular endothelial cells in 100% and 50% of 28 lupus kidney specimens except for necrotic or sclerotic lesions. HLA-DQ was expressed in a high incidence of 67%, 86% in patients with proliferative LN (WHO Class III-IV) and active lesions, respectively. Serum gamma-IFN and sIL-2R levels were 1.2 +/- 0.2 U/ml and 190 +/- 24 U/ml (mean +/- SEM; N = 30) in normal controls, and elevated in patients with proliferative LN (4.1 +/- 1.0 U/ml, 383 +/- 81 U/ml, N = 25), especially with active lesions (6.2 +/- 1.5 U/ml, 500 +/- 110 U/ml, N = 14). Overall, glomerular lesions such as HLA-DQ expression, the activity index and leukocyte infiltration correlated positively with serum gamma-IFN levels (r = 0.55; P less than 0.01 for HLA-DQ, r = 0.68; P less than 0.001 for activity index, r = 0.38; P less than 0.05 for leukocyte infiltration), but not with serum sIL-2R levels, anti-DNA antibody titers and CH50 titers.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1992

Adenosquamous carcinoma of the lung. Clinicopathologic and immunohistochemical features.

Adenosquamous carcinomas (ASC) of the lung comprise only 1.8% of all pulmonary cancers. Eleven patients with this disease (6 men and 5 women; mean age, 62 years [range, 51 to 78 years]) were treated. On the basis of pathologic and immunohistochemical evidence, the tumors were separated into three groups: five ASCs of predominantly glandular type, which may originate from squamous metaplasia in a preexisting adenocarcinoma; three mixed type ASCs, possibly derived from the transition of undifferentiated carcinoma to two different elements; and three predominantly squamous type ASCs resembling high-grade muco-epidermoid carcinoma. The 5-year survival rate of 35% for patients with ASCs was the same as that for patients with other nonsmall cell carcinomas. For two patients with ASCs of the predominantly glandular type and for one with the mixed type, resection was incomplete because of extensive local disease. All tumors of the predominantly squamous type could be excised completely. However, differences in the malignant potential of these three types of ASCs are still controversial.

Adenocarcinoma↗

PubMed1992

Age-dependent decrease in histamine H1 receptor in human brains revealed by PET.

Age-related changes in histamine H1 receptors were studied using [11C]pyrilamine or [11C]doxepin by positron emission tomography (PET). The frontal, parietal and temporal cortices showed age-related decreases in binding of approximately 13% per decade. In contrast, the thalamus showed no apparent decrease in binding during normal ageing because of its higher nonspecific binding. Post mortem studies also indicated that the nonspecific binding of [3H]pyrilamine in the thalamus was approximately 112% higher than that in the cortex. However, no significant decrease in histamine H1 receptors with age was observed by in vitro binding assays of autopsied human frontal cortex. Possible reasons are given for the larger effects of age observed in the PET study than in the in vitro post mortem binding study.

Adolescent↗

PubMed1992

Mapping of histamine H1 receptors in the human brain using [11C]pyrilamine and positron emission tomography.

We have studied the characteristics of carbon-11 labeled pyrilamine as a radioligand for investigating histamine H1 receptors in human brain with positron emission tomography (PET). [11C]Pyrilamine is distributed evenly in proportion to cerebral blood flow at initial PET images. Later (after 45-60 min), 11C radioactivity was observed at high concentrations in the frontal and temporal cortex, hippocampus, and thalamus, and at low concentrations in the cerebellum and pons. The regional distribution of the carbon-11 labeled compound in the brain corresponded well with that of the histamine H1 receptors determined in vitro in autopsied materials. In six controls, the frontal and temporal cortices/cerebellum ratio increased during the first 60 min to reach a value of 1.22 +/- 0.071. Intravenous administration of d-chlorpheniramine (5 mg) completely abolished the specific binding in vivo in the frontal cortex and temporal cortex (cortex/cerebellum ratio, 0.955 +/- 0.015). The availability of this method for measuring histamine H1 receptors in vivo in humans will facilitate studies on neurological and psychiatric disorders in which histamine H1 receptors are thought to be abnormal.

Adult↗

PubMed1992

Isolation of Pseudomonas pickettii strains that degrade 2,4,6-trichlorophenol and their dechlorination of chlorophenols.

Three strains of Pseudomonas pickettii that can grow with 2,4,6-trichlorophenol (2,4,6-TCP) as the sole source of carbon and energy were isolated from different mixed cultures of soil bacterial populations that had been acclimatized to 2,4,6-TCP. These strains released 3 mol of chloride ion from 1 mol of 2,4,6-TCP during the complete degradation of the TCP. Of these strains, P. pickettii DTP0602 in high-cell-density suspension cultures dechlorinated various chlorophenols (CPs). Cells that were preincubated with 2,4,6-TCP converted isomers of 4-CP to the corresponding chloro-p-hydroquinones, but those preincubated with 4-CP converted CPs lacking a chlorine atom(s) at the o position to isomers of chlorocatechol. The ability of DTP0602 to dechlorinate 2,4,6-TCP was induced by 2,6-dichlorophenol, 2,3,6- and 2,4,6-TCP, and 2,3,4,6-tetrachlorophenol and was repressed in the presence of succinate or glucose.

Biodegradation, Environmental↗

PubMed1992

Passive protective effect of chicken egg yolk immunoglobulins against experimental enterotoxigenic Escherichia coli infection in neonatal piglets.

Passive protection of neonatal piglets against fatal enteric colibacillosis was achieved with powder preparations of specific antibodies against K88, K99, and 987P fimbrial adhesins of enterotoxigenic Escherichia coli. The antibody powders were obtained by spray drying the water-soluble protein fraction of egg yolks from immunized hens after the lipid components were precipitated with an aqueous dispersion of acrylic resins (Eudragit L30D-55; Rohm pharma). The anti-K88, -K99, and -987P antibody preparations reacted specifically against the corresponding fimbrial antigens in an enzyme-linked immunosorbent assay. The orally administered antibodies protected in a dose-dependent fashion against infection with each of the three homologous strains of E. coli in passive immunization trials with a colostrum-deprived piglet model of enterotoxigenic E. coli diarrhea. Scanning electron microscopy revealed adherence of enterotoxigenic E. coli in intestinal epithelial surfaces of control piglets, whereas in treated piglets treated with high-titer antibodies, a resistance to bacterial adhesion was observed. An enzyme immunoassay with avidin-biotin complex demonstrated specific local antibody activity in target areas of the small intestines. In vitro, E. coli K88+, K99+, and 987P+ strains adhered equally to porcine duodenal and ileal epithelial cells but failed to do so in the presence of homologous anti-fimbrial antibodies. Absorption of egg yolk antibodies with fimbrial immunosorbent removed the anti-fimbrial antibody fraction and reduced significantly the protective nature of the antibody preparation in a passive immunization experiment, suggesting that anti-fimbrial antibodies were the active components.

Animals↗

PubMed1992

Neurogenic bladder due to peripheral neuropathy and a visual disturbance in an elderly man with systemic lupus erythematosus.

A 63 year old man with central nervous system lupus with a neurogenic bladder and visual disturbance is described. The diagnosis of neurogenic bladder, attributed to peripheral neuropathy, was made on the basis of cystometrography and clinical symptoms. A brain magnetic resonance imaging scan showed gliosis along the cerebral vessels and the optic nerve. This case shows that systemic lupus erythematosus can be accompanied by a peripheral neurogenic bladder and visual disturbance, and that these symptoms may not improve despite the amelioration of other lupus symptoms on treatment with steroids.

Follow-Up Studies↗