Biomedical subjects
Publications and source records attributed to T Hayama.
In this review, I will describe honeybee biology from my prospective as a veterinary pharmacologist and will provide a summary of my research project to search for effective drugs to control American foulbrood, a bacterial disease of honeybees. In conclusion, mirosamicin, a macrolide antibiotic, as a preventive and glutaral, an alkylating agent, as a disinfectant were the most promising drugs.
Bioavailabilities of oral rumen-protected and non-protected formulations of sulfamethoxazole (SMS) were compared in ruminating calves, since in vitro degradation of SMX in ruminal fluid was confirmed. The coated with a gastric-acid-soluble polymer and uncoated formulations were administered to 3 calves through a catheter. Neither formulation could produce sufficient blood concentration of the drug, though the bioavailability of SMX for the coated formulation was higher than that for the uncoated formulation. It was suggested that the rumen-protected drug could improve the bioavailability by escaping from degradation in the rumen, but scarcely attain the effective levels in blood.
Disposition profile of ampicillin (ABPC) among honeybees, larvae, honey and royal jelly in a hive after oral dosing to adult bees was studied. Four honeybee colonies were administered the single dose of ABPC at the rate of 30 mg/hive by addition to sugar syrup or pollen substitute (paste) for 1 day intake. The colonies received ABPC in syrup showed high drug residue levels in honey and it lasted over 14 days beyond the detection limit of residual analysis. In the hives given ABPC in paste, relatively low honey residues were found, however, the distributions of the drug in young larvae and jelly which was the food of the larvae were very low. ABPC was considered to be a promising drug for the control of American foulbrood, an important bacterial disease of honeybee larvae, because of its high antibacterial activity to the pathogen, Paenibacillus larvae, and instability of residue in honey as human food. The low distribution in young larvae, the target of the disease, threw a doubt on the efficacy of ABPC for American foulbrood control.
Sporicidal activities of glutaraldehyde, sodium hypochlorite, povidone iodine, ethylene oxide gas, chlorhexidine gluconate, and didecyl dimethylammonium chloride on wet and dry spores of Paenibacillus larvae (basonym: Bacillus larvae) were evaluated for control of honeybee American foulbrood. Glutaraldehyde was found to have a strong and rapid effect on both the wet and the dry spores among the disinfectants tested.
The suppressive effect of N-(benzyloxycarbonyl)-L-phenylalanyl-L-tyrosinal on bone resorption was examined in vitro and in vivo. This synthetic peptidyl aldehyde was found to be a potent and selective cathepsin L inhibitor in our screening for cysteine protease inhibitors. In the pit formation assay with unfractionated rat bone cells, 1.5 nM of this compound markedly inhibited parathyroid hormone-stimulated osteoclastic bone resorption. In addition, intraperitoneal administration of this peptidyl aldehyde (2.5-10 mg/kg) for 4 weeks suppressed bone weight loss dose dependently in the ovariectomized mouse, experimental model of osteoporosis. Hydroxyproline measurement of the decalcified femurs from these ovariectomized mice suggested that this compound acts as a bone resorption suppressor through the inhibition of collagen degradation.
We present the unusual case of 16-year-old girl who developed intractable convulsions five days after the onset of a cold. Meningeal signs, lymphopenia, proteinuria, and lupus anticoagulant were also present. Treatment with anticonvulsants, antituberculous agents, and adenine arabinoside were ineffective. The initiation of methylprednisolone pulse therapy immediately resolved convulsions and fever. The diagnosis, suggested by the clinical course and the marked improvement of the meningoencephalitis by pulse therapy, was an encephalitic form of acute disseminated encephalomyelitis. Clinical and laboratory findings indicated that an immune disorder may have triggered an abnormal response to a viral infection leading to this patient's neurologic disorder.
The genetic differences between two types of dominant inherited myoclonus epilepsy, dentatorubral pallidoluysian atrophy (DRPLA) and benign adult familial myoclonus epilepsy (BAFME), have been reported. A gene with a CAG repeat expansion responsible for DRPLA has been isolated. We have examined CAG repeat expansion in the DRPLA gene in five BAFME families, and the abnormal CAG expansion was not observed in the affected subjects. Linkage analysis using DNA polymorphisms in the DRPLA gene and the genes for gamma-aminobutyric acid (GABA) receptor subunits, GABAR beta 1, GABAR beta 3, and GABAR alpha 6, showed that these genes were not responsible for BAFME.
The effect of reflex closure of the esophageal groove induced by the accustomed milking procedure on absorption of sulfamethoxazole (SMX)-trimethoprim (TMP) combination was examined, using calves trained to suck through a nipple-bucket. The experiment was carried out with a two-way cross-over design in which 2 groups of 5 calves of 6 weeks old were used. SMX-TMP combination was administered to the calves in each group through a nipple-bucket or an esophageal catheter. Tmax of SMX after nipple-bucket dosing was about 40 min shorter than that after catheter dosing. Cmax and AUC of SMX after the nipple-bucket dosing were 7.5 times greater and 6.9 times larger than those after the catheter dosing, respectively. Plasma TMP concentration was measurable only after the nipple-bucket dosing. These results suggest that a large portion of the drugs administered by the nipple-bucket dosing, which induces closure of the esophageal groove, were transferred directly into the abomasum resulting in higher bioavailabilities of the drugs.
The biological properties and susceptibility to antimicrobial agents of Bacillus larvae were examined. Twenty-nine strains, 28 isolates from each outbreak of American foulbrood in Japan and a B. larvae type strain (ATCC 9545T) were used. our B. larvae isolates had almost the same biological properties as the type strain. The isolates were more susceptible to penicillins, macrolides and lincomycin, a lincosamide, than other antimicrobials. Microsamicin among the macrolides and ampicillin among the penicillins appeared to be the most effective agents.
Analogues of the natural product endothelin A (ETA) receptor antagonists cyclo(-D-Trp1-D-Glu2-Ala3-D-Val4-Leu5-) (1) and cyclo(-D-Trp1-D-Glu2-Ala3-D-alloIle4-Leu5-) (2) were prepared and tested for inhibitory activity against [125I]endothelin (ET-1) binding to protein ETA receptors. The DDLDL chirality sequence of the natural products appeared to be critical for inhibitory activity because conversion of either D-Trp or D-Glu (or both) in 1 to the corresponding L-isomer(s) abolished this property. Systematic modifications at each position of the natural products clarified the structure-activity relationships and led to highly potent and selective ETA receptor antagonists. Most replacements of D-Trp1 and Leu5 with other amino acids caused a significant loss of inhibitory activity. In contrast, replacement of D-Glu2 with D-Asp2 enhanced the activity. With regard to the Ala3 position, all analogues with imino acids, independent of being cyclic or acyclic, showed higher affinities than did the amino acid analogues. In addition, most replacements with amino acids, which had various functional groups in their side chains, did not significantly modify ETA binding affinity. The D-Val4/D-alloIle4 position was very important for inhibitory activity, and a beta-position branched D-amino acid or a D-heteroarylglycine was preferable at this position. Among synthesized cyclic pentapeptides, compound 36 (BQ-518) was the most potent ETA receptor antagonist, with a pA2 of 8.1 against ET-1-induced vasoconstriction in isolated porcine coronary arteries. This compound also showed the greatest selectivity between ETA and ETB receptors (IC50 for human ETA = 1.2 nM, IC50 for human ETB = 55 microM). In contrast, compound 8 (BQ-123) is a highly soluble, potent, and selective ETA receptor antagonist (pA2 = 7.4, IC50 for human ETA = 8.3 nM, IC50 for human ETB = 61 microM). The sodium salt of 8 is practically freely soluble in saline. These compounds are useful tools for not only in vitro but also in vivo pharmacological studies.
BACKGROUND AND PURPOSE: Tau-like immunoreactivity is known to develop in neurons under some experimental conditions simulating ischemia. The purpose of this study is to investigate the expression of tau-like immunoreactivity in the human brain after ischemic insult. METHODS: A series of autopsied human brains with or without ischemic lesion were investigated with immunohistochemistry (Alz-50, anti-tau, and anti-ubiquitin) and with silver-staining methods (Gallyas and Bodian methods). RESULTS: Punctate immunoreactivity to Alz-50 was visualized in the cytoplasm not only of the neurons in and around the ischemic lesion but also of the neurons free from classic ischemic changes around the necrosis. Some of the neurons around the ischemic lesion were stained by the Gallyas method. Immunostaining with anti-tau and anti-ubiquitin antibodies and the conventional Bodian method failed to visualize these neurons. CONCLUSIONS: The widespread appearance of Alz-50 immunoreactive neurons during the ischemic process signifies that tau-related proteins may be related to ischemic necrosis, but the lack of neurofibrillary tangles morphologically distinguishes ischemic development of tau-related proteins from the neurofibrillary degeneration in Alzheimer's disease.
In vivo efficacy of orally administered lufenuron, an insect growth regulator, in disinfesting cat fleas was evaluated, using flea-free cats and dogs which were purchased and infested every 10 days with cat fleas from a colony kept in our laboratory. Lufenuron was orally administered as a single dose of 15, 30, or 60 mg/kg to cats, and 5, 10 or 20 mg/kg to dogs. In cats, adult flea emergence was intensively prevented for 30 days by dosing of 15 mg/kg of lufenuron and 40 days by 30 or 60 mg/kg. The average egg hatch rate in 15 mg/kg group was, however, significantly higher than those in 30 mg/kg or more, suggesting necessity to dose 30 mg/kg to cats to prevent development of cat fleas effectively. In dogs, a lower dose of the drug, 10 mg/kg seemed to be sufficient for the complete prevention of flea development.
We studied the effects of cytokines such as IL-1 alpha, IL-6 and TNF alpha, and lipopolysaccharide (LPS) on cultured human monocytes. Increased fibronectin (FN) production, as a indicator of the activation of monocytes, was observed with any cytokines or LPS stimulation those were added in the culture medium. These increased FN production by cytokines showed a dose dependent fashion, and 4 hours culture with these cytokines was enough to obtain the amount of FN measured with radioimmunoassay. The combination of sub-optimal dose of cytokines (IL-1 alpha + IL-6, IL-1 alpha, IL-6 + TNF alpha), that could not induce substantial amount of FN with any single cytokine, also could induce FN by cultured monocytes. The specificity of cytokines for the FN production by cultured monocytes was confirmed by the neutralization using monoclonal antibodies specific for each monokines. Northern blot analysis with cDNA specific for FN confirmed the expression of FN mRNA in cultured monocytes stimulated with cytokines or LPS. Cytokine network plays an essential role for immune and inflammatory reaction, and FN has been shown to induce monokines through VLA-5 receptor on cultured monocytes. Our data suggests that monocytes may not always require high concentration of cytokines for the activation of monocytes in vitro, and that the synergistic action of low concentration of cytokines for the activation was enough for the progression of immune or inflammatory reaction.
A 68-year-old woman had been complained of xerostomia since she was 30 years old. Further symptoms of polyuria, polyposia and insomnia had been developed since she was 35 years old. The biopsy material from a minor salivary gland demonstrated the infiltration of lymphocytes into mesenchyme which was compatible with Sjögren's syndrome. She admitted to our hospital because of myalgia in bilateral gastrocnemius and petechiae in both lower extremities in addition to the complaints described above. Complete blood cell counts on admission revealed hemoglobin 9.7 g/dl, platelet count 12.5 x 10(4)/microliters, and white blood cell count 3,300/microliters. Marked polyuria, polyposia (more than 5,000 ml/day, respectively) and low urine gravity (1.005) were observed, although the serum creatinine level showed normal value. Serologic examination showed that the elevation of total serum protein concentration (9.5 g/dl) with marked elevation of serum IgG level (6,190 mg/dl). Her immunoglobulins contained cryoglobulin (cryocrit 20%), and immunoelectrophoresis demonstrated the existence of IgG-kappa monoclonal protein. A positive anti-nuclear antibody at 1:320 dilution, a positive rheumatoid factor and a positive antibody to SS-A (Ro) were also observed. The serial studies of blood gas analysis could not demonstrated the presence of metabolic acidosis. Together with the result of elevated plasma antidiuretic hormone level and results of vasopressin test, Fishberg's concentrating test and the tests of the overload of NH4Cl or bicarbonate, she was diagnosed Sjögren's syndrome with both diabetes insipidus and subclinical renal tubular acidosis. She was initially medicated with prednisolone (40 mg/day, orally), then she was given six courses of intravenous cyclophosphamide (750 mg/body/month).(ABSTRACT TRUNCATED AT 250 WORDS)
A 76-year-old man was admitted to Kisen hospital because of lumbago and chest pain. Laboratory examinations revealed a chronic renal failure with marked elevation of the serum BUN (48.8 mg/dl) and creatinine levels (8.2 mg/dl). The serum electrophoresis demonstrated a hypergammaglobulinemia with M peaks. An immunoelectrophoresis demonstrated monoclonal IgD-lambda and IgG-kappa proteins in the serum, and lambda-type Bence Jones protein in the urine (0.4 g/day). Bone marrow smears revealed an abnormal proliferation of atypical plasma cells (43%). A systemic X-ray examination of the skeletal system showed systemic osteoporosis without punched out lesion. The patient was diagnosed as having IgD-lambda type multiple myeloma and IgG-kappa type benign monoclonal gammopathy by quantifying concentration of two M proteins (1,160 mg/dl in IgD, 1,179 mg/dl in IgG, respectively). A combination chemotherapy with melphalan and prednisolone was administered monthly for multiple myeloma, and hemodialysis for the renal failure was performed 3 times a week. A marked improvement of his laboratory findings including a diminution of the serum IgD-lambda M-protein was obtained. On the other hand, IgG-kappa M-protein level was unchanged. Two M-protein levels showed a different behavior after the combination chemotherapy. Although the patient died of congestive heart failure, the partial remission of multiple myeloma has been maintained for 16 months with chemotherapy.
To locate a taste-related region in the thalamic reticular nucleus (Rt), we explored a reticular region having connections with the thalamic taste relay and the cortical taste area (CTA), by neuronal tracing methods using HRP, WGA-HRP and biocytin. Tracer injections at the thalamic taste relay, i.e., the parvicellular part of the thalamic posteromedial ventral nucleus (VPMpc), labeled cell bodies and axon terminals in a confined portion of the ipsilateral Rt. This was located at the ventromedial-most portion of the nucleus at the level of approx. 1.2 mm rostral to the rostral end of the VPMpc. Tracer injections at the CTA ipsilaterally labeled axon terminals in the same region of the Rt, as did the thalamic injections. When WGA-HRP was injected at this taste-related region in the Rt, we observed labeled cell bodies in layer VI in the CTA; in the VPMpc we saw densely labeled axon terminals but few, if any, labeled cell bodies. The results indicated that the taste-related region in the Rt receives input from the VPMpc and CTA, and sends output to the VPMpc. They also showed that the reticulo-thalamic projections were much heavier than the thalamo-reticular ones in the taste system.
Despite many suicidal cases in patients with systemic lupus erythematosus (SLE), literature on this subject is lacking. To elucidate and prevent this phenomenon, we re-evaluated the clinical records of seven suicidal patients with SLE. Six patients had photosensitivity and insomnia. At the time of the suicide attempt, hypocomplementemia was observed in five of six patients. Diffuse slowing on electroencephalograms were observed in four of five patients. One patient successfully committed suicide while on no therapy while five patients made their attempts under the tapering courses of steroids. Five patients manifested psychoses whereas two patients displayed no psychotic findings. All patients attempted suicide shortly after admission (mean time 20 days). The subsequent courses of the survivors who received more medication were favorable. Therefore, it appears that disease activity was not fully controlled in these patients. Furthermore, signs of an imminent suicide attempt were missed in some cases. Psychosis, insomnia, history of photosensitivity, an incompletely controlled disease state, receiving tapering steroid dose, diffuse slowings on electroencephalograms and the presence of hypocomplementemia appeared to be risks for attempting suicide in SLE. We would recommend that such patients be under psychiatric care for at least 2 months to prevent suicide. When the patient is still psychotic or unstable, further medical care will be required.
Recently, the annual reduction in the incidence rate of tuberculosis has slowed in Japan. One reason for this trend is believed to be due to an increase in the number of immunocompromised hosts. In our department, we discovered 10 cases of pulmonary tuberculosis among 962 cases of collagenosis, and have analyzed the factors for the development of pulmonary tuberculosis in these patients. A total of 29 patients wer involved in the study: 22 with systemic lupus erythematosus (SLE) (active disease, 10; inactive disease, 12) and having no pulmonary complications, and seven with pulmonary tuberculosis and no concomitant diseases. Our findings were as follows: 1. Seven of the 10 patients with pulmonary tuberculosis also suffered from SLE. 2. Nine of the 10 patients had been treated with a corticosteroid or immunosuppressant. 3. Serum CH50 and erythrocyte sedimentation rate (ESR) were valuable indicators for diagnosing pulmonary tuberculosis in the patients with SLE. 4. Patients with SLE and pulmonary tuberculosis tended to show lymphopenia in peripheral blood, which was further enhanced by prolonged use of steroids. 5. Miliary tuberculosis rather than pulmonary tuberculosis tended to develop in elderly patients, and required longer hospitalization.