Lysine deficient diet and lysine replacement affect food directed operant behavior

As a test for specific hunger for amino acids with the goal of identifying brain regions which might mediate motivation to alleviate L-lysine (Lys) deficiency, rats were trained to lever press to receive complete diet. Rats were given Lys deficient (Lys-def) diet ad lib. Intraperitoneal (IP) injection of Lys, 2 h before the test session, inhibited lever pressing. Lys injected animals pressed at nearly the same low rate as did animals fed ad lib complete diet, although the response of saline injected animals was also partially decreased. Next, osmotic minipumps were implanted IP and animals given Lys-def diet ad lib. Chronic Lys infusion also strongly inhibited lever pressing. Rats allowed ad lib access to Lys to drink drank significantly more Lys than when given complete diet. Lys chronically infused by minipump into the lateral hypothalamus, also inhibited pressing by rats given Lys-def diet. Therefore, animals lacking Lys in the diet will work to receive complete diet, but replacement of Lys by drinking, chronic IP infusion, or directly into the lateral hypothalamic area inhibits bar pressing behavior.

Cervical/vaginal dysplasias of transgenic mice harbouring human papillomavirus type 16 E6-E7 genes

Half of the female transgenic mice harbouring human papillomavirus type 16 (HPV-16) E6-E7 genes under control of the mouse mammary tumour virus promoter, developed malignant tumours, including salivary gland carcinomas, lymphomas and skin histiocytomas. Although the E6-E7 genes are aetiological factors for human anogenital carcinoma, the transgenic mice produced no tumours in the anogenital tract. We investigated cytological and histological changes in the anogenital tract of the same transgenic mice. Seventeen (77%) of 22 transgenic mice developed dysplastic and/or hyperplastic changes in the cervix and vagina. HPV-16 E6-E7 mRNA signals were observed in the genital lesions, while they were not detected in the normal cervices and vaginas of transgenic mice and control mice by RNA in situ hybridization analysis. RNA/PCR analysis using poly(A)+ RNA showed that only a full-length E6-E7 RNA was expressed in three scraped cell samples from dysplasia, whereas full-length and spliced E6-E7 transcripts were in three cell samples from dysplasia/hyperplasia. These results suggest that expression of both E6 and E7 genes of HPV-16 is important for inducing dysplastic and hyperplastic changes in the genital epithelium.

CAG expansions in a novel gene for Machado-Joseph disease at chromosome 14q32.1

We have identified a novel gene containing CAG repeats and mapped it to chromosome 14q32.1, the genetic locus for Machado-Joseph disease (MJD). In normal individuals the gene contains between 13 and 36 CAG repeats, whereas most of the clinically diagnosed patients and all of the affected members of a family with the clinical and pathological diagnosis of MJD show expansion of the repeat-number (from 68-79). Southern blot analyses and genomic cloning demonstrates the existence of related genes. These results raise the possibility that similar abnormalities in related genes may give rise to diseases similar to MJD.

Autoregulation of histamine release via the histamine H3 receptor on mast cells in the rat skin

The autoregulation of the histamine release via the histamine H3 receptor in the periphery was studied in vivo and in vitro. Antidromic electrical stimulation of the sciatic nerve caused a significant increase in histamine release in the subcutaneous perfusate in the rat hindpaw. (R)alpha-methylhistamine, a specific H3 receptor agonist, significantly and dose-dependently inhibited the increase in release of histamine by antidromic stimulation at intravenous doses of 0.25-2 mg/kg. Thioperamide (2 mg/kg, intraperitoneally), a specific H3 antagonist, prevented the inhibitory effect of (R)alpha-methylhistamine. Substance P perfusion (5-50 microM) also elicited a significant increase in histamine, and a significant inhibition by (R)alpha-methylhistamine and the antagonism of thioperamide were observed. (R)alpha-methylhistamine inhibited the histamine release by substance P from rat peritoneal mast cells in vitro, and thioperamide reduced the response to (R)alpha-methylhistamine. These data suggest that mast cells may have histamine H3 receptors, and that histamine probably modulates its own release through the H3 receptor in neurogenic inflammation.

Nucleotide receptors in hepatic stellate cells of the rat

When hepatic stellate cells were stimulated by UTP, ATP, or ADP, cellular levels of inositol phosphates significantly increased (UTP > ATP > ADP > 5'-O-(3-thiotriphosphate). Thirty min after incubation with 100 microM of UTP, ATP, or ADP, levels of inositol monophosphate increased to 1318 +/- 116, 616 +/- 87 and 591 +/- 234% of control levels, respectively, with concomitant increase in the production of inositol trisphosphate and bisphosphate. These nucleotides transiently increased the [Ca2+]i of fura-2-loaded stellate cells. Moreover, UTP, ATP, ADP and adenosine 5'-O-(3-thiotriphosphate) were able to induce contraction of stellate cells as detected using the silicone-rubber membrane method. These results suggested that hepatic stellate cells have nucleotide receptors which react predominantly with extracellular UTP and ATP and trigger the receptor-mediated contraction of the cells.

Antioxidant, gallic acid, induces apoptosis in HL-60RG cells

Gallic acid, a naturally occurring plant phenol with antioxidative activity, was found to induce cell death in promyelocytic leukemia HL-60RG cells, although many antioxidants are well known to protect the cell from oxidative stress. Morphological and biochemical studies indicated that the gallic acid-induced cell death is apoptosis. Flow cytometric analysis revealed that the apoptosis was not triggered at a specific phase of the cell cycle and that 2 h exposure of gallic acid to HL-60RG cells was enough to induce apoptosis. The inhibitory assay suggested that gallic acid-induced cell death was mediated by reactive oxygen species such as hydrogen peroxide, superoxide anion in addition to Ca2+ ion, calmodulin-dependent enzymes. Structure-activity analysis suggests that gallic acid induces apoptosis in HL-60RG cells, depending on its distinctive feature derived from the structure but not on its antioxidative activity.

Dynamic aspects of glutathione metabolism in obstructive jaundice

The dynamic aspects of glutathione metabolism during obstructive jaundice were analyzed in rats. Plasma bilirubin levels increased after ligation of the bile duct, with a concomitant increase in hepatorenal glutathione levels. When the bile duct was recanalized, plasma bilirubin levels rapidly decreased, with a concomitant decrease in hepatorenal glutathione levels. The half-life of hepatic glutathione turnover increased markedly after bile duct obstruction, returning to normal after recanalization of the bile duct. Intravenous administration of a loading dose of bilirubin inhibited the biliary secretion of glutathione in a dose-dependent manner. On the other hand, renal glutathione efflux increased markedly after bile duct obstruction. These observations suggest that glutathione status is significantly affected in obstructive jaundice, predominantly due to the inhibition of hepatic secretion by increased bilirubin.

An androgen receptor mutation causing androgen resistance in undervirilized male syndrome

The molecular basis of androgen resistance was investigated in a patient with undervirilized male syndrome. Binding studies of the androgen receptors in the patient's genital skin fibroblasts revealed a normal binding capacity of 5 alpha-dihydrotestosterone, although the affinity to androgen was slightly lower than the normal control value. The androgen binding of the patient's receptor showed a moderate thermal instability when the assay temperature was raised from 30 to 41 C. Nucleotide sequencing analysis of the androgen receptor gene revealed a single nucleotide substitution in exon F, resulting in an amino acid alteration from leucine (CTC) to phenylalanine (TTC) at position 789 within the steroid-binding domain of androgen receptor. When expressed in COS-7 cells, the mutant androgen receptor harboring phenylalanine at position 789 showed thermolabile androgen-binding properties similar to those observed in the patient's genital skin fibroblasts. Cotransfection experiments with an androgen-inducible reporter gene demonstrated a decreased transactivational capability of the mutant receptor. These results indicate that this point mutation modified the receptor function and caused androgen resistance in this patient. This mutation caused the mildest form of all androgen insensitivity syndromes ever examined for mutations in the androgen receptor gene.

Progression and regression of atherosclerotic findings in the descending thoracic aorta detected by enhanced computed tomography

Reports evaluating the progression and regression of atherosclerosis by non-invasive procedure are still limited. We investigated the progression and regression of atherosclerotic intimal thickening of the descending thoracic aorta non-invasively measured by enhanced computed tomography in 83 patients (average age 51.0 years) at the beginning and end of a 2.5 year period. The patients were not taking anti-hypertensive, lipid-lowering or hypoglycemic drugs and therefore we consider them as a natural history cohort. At entry, the extent of aortic intimal thickening was 35.2% of the circumference of the cross-section of the wall, which increased to 39.7% after 2.5 years. Spontaneous progression was associated directly with age, elevated levels of total cholesterol, LDL-cholesterol, LDL/HDL cholesterol ratio, diastolic blood pressure, and inversely to HDL-cholesterol. There was little correlation with triglycerides, systolic blood pressure, fasting glucose or body mass index. In 65 of the patients, aortic atherosclerosis progressed, while in 9 patients it remained unchanged, and in a further 9 it regressed. The levels of lipid variables, apart from HDL-cholesterol, and diastolic blood pressure in the patients with spontaneous progression were significantly higher than in the unchanged and spontaneous regression. Thus, this study verified the natural history of aortic atherosclerosis non-invasively measured by enhanced CT.

Effects of E-4031 on atrial fibrillation threshold in guinea pig atria: comparative study with class I antiarrhythmic drugs

The effects of E-4031, a new class III antiarrhythmic agent, on atrial fibrillation threshold (AFT), atrial effective refractory period (ERP), and interatrial conduction time (ACT) were investigated in Langendorff-perfused guinea pig hearts; the results were then compared with those of the class I agents disopyramide, procainamide, lidocaine, and flecainide. Whole guinea pig hearts were perfused with Tyrode's solution containing acetylcholine (ACh 3 x 10(-7) M). The three indexes were measured before and after administration of the test drugs, using right atrial extrastimulus and 50-Hz continuous stimulation. Disopyramide, procainamide, and flecainide (> or = 10(-6) M) significantly increased AFT. Although E-4031 (> or = 3 x 10(-6) M) also increased AFT, this effect was less potent than that observed with the other drugs. E-4031 (> or = 10(-6) M) significantly prolonged ERP, and this prolongation was less pronounced than that observed with disopyramide but similar to that observed with procainamide or flecainide. E-4031 did not affect ACT, and the greatest prolongation of ACT was observed with flecainide. Lidocaine had no effect on any of the indexes. These findings suggest that in guinea pig hearts E-4031 exerts an antifibrillatory effect by prolonging atrial ERP alone, but this effect is less pronounced than that observed with class I drugs, because AFT measured by 50-Hz continuous stimulation is influenced by both ERP and ACT.

AICA riboside improves myocardial ischemia in coronary microembolization in dogs

This study was undertaken to examine whether 5-amino-4-imidazolecarboxamide (AICA) riboside (acadesine), which augments adenosine release in ischemic myocardium, further attenuates ischemic injury after acute coronary microembolization. The left anterior descending coronary artery was cannulated and perfused with blood from the left carotid artery in 46 dogs, and coronary blood flow (CBF) of the perfused area was measured. In 12 dogs, 15-microns microspheres (5.0 x 10(4)/ml) were injected repeatedly until CBF approached zero. Changes in CBF, fractional shortening, lactate extraction ratio, and adenosine release were measured with and without administration of AICA riboside. In the control group (n = 7), CBF increased to 154 +/- 11 ml.100 g-1.min-1 at 16-30% of total coronary embolization, and adenosine release was 6.1 +/- 1.0 nmol.100 g-1.min-1. Administration of AICA riboside (n = 5) enhanced coronary hyperemia (187 +/- 8 ml.100 g-1.min-1, P < 0.05), adenosine release (11.9 +/- 0.9 nmol.100 g-1.min-1, P < 0.001), and myocardial adenosine content (0.434 +/- 0.069 vs. 0.118 +/- 0.019 nmol/mg wet wt, P < 0.01) and attenuated decreases in fractional shortening and lactate extraction ratio. AICA riboside preserved myocardial tissue ATP content of the embolized area. The administrations of 8-phenyltheophylline (n = 12) and alpha,beta-methyleneadenosine 5'-diphosphate (n = 10) abolished the beneficial effects of AICA riboside. Furthermore, AICA riboside increased ectosolic and cytosolic 5'-nucleotidase activity of the embolized myocardium (n = 12). Thus we conclude that AICA riboside attenuates contractile and metabolic dysfunction by enhancing adenosine release via activation of ectosolic 5'-nucleotidase and inducing local hyperemia in acute coronary microembolization.

Thymic lesions in chicken infected with infectious bursal disease virus

Thymic lesions were investigated in specific-pathogen-free chickens infected with the highly virulent HPS-2 strain or virulent reference GBF-1 strain of infectious bursal disease virus (IBDV). Both viruses induced follicular lymphoid necrosis and depletion in the bursa, as well as thymic lesions. However, cortical lymphocyte condensation and depletion in the thymus were more prominent in the HPS-2 group than in the GBF-1 group. Electronmicroscopically, alterations of cortical lymphocytes were characterized by nuclear disintegration resembling apoptosis. Immunohistologically, the virus-antigen-positive epithelial reticular cells in the medulla were more extensive in the HPS-2 group. These results suggest that HPS-2 IBDV persists in the thymic medulla and that cortical lymphocyte depletion is caused by virus-induced apoptosis.

Malignant schwannoma in a case of type 1 neurofibromatosis with decreased immunoreactivity of smooth muscle alpha-actin in tumor vessels

A malignant schwannoma in the left calf of a 37-year-old man with type 1 neurofibromatosis is herein reported. Since it is known that capillaries in benign neurofibromas are accompanied by hypertrophic pericytes expressing an abundant amount of smooth muscle alpha-actin (SMAA), we examined the immunohistochemical reactivity of SMAA within this malignant tumor and then compared it with that in surrounding benign areas. In the nests of malignant cells, decreased SMAA staining was found in the capillary walls. In the benign tissues around the malignant tumor, various extents of SMAA could be visualized in the vessels and myofibroblasts. Platelet-derived growth factor (PDGF) was also detected in the tumor, suggesting that cytokines secreted by malignant cells may have an influence on the expression of SMAA as well as on the alteration of the structure of blood vessels.

Comparative conformational analyses of mu-selective dermorphin and delta-selective deltorphin-II in aqueous solution by 1H-NMR spectroscopy

Two-dimensional 1H-NMR methods have been used to obtain complete proton resonance assignments and possible solution conformations of dermorphin (H-Tyr-D-Ala-Phe-Gly-Tyr-Pro-Ser-NH2) and deltorphin-II (H-Tyr-D-Ala-Phe-Glu-Val-Val-Gly-NH2), naturally occurring mu- and delta-selective opioids, respectively, in order to examine the conformational characteristics that are closely related to the selectivities towards mu/delta-opioid receptors. With the use of the proton-proton distances derived from ROESY measurements in aqueous solution, 50 possible 3D structures are generated by means of distance geometry calculations. The conformers which satisfy the distance constraints and the torsion angles estimated from JNHC alpha H vicinal coupling constants within the allowable range are then subjected to molecular dynamics simulations for 10 ps after equilibration. Although dermorphin and deltorphin-II are both in equilibrium among many flexible conformers, some conformational differences are observed between these peptides: many conformers of dermorphin show a structure rounded at the N-terminal Tyr-D-Ala-Phe-Gly-Tyr and C-terminal Gly-Tyr-Pro-Ser-NH2 moieties, which are almost at right angles to each other, while those of deltorphin-II are characterized by a 'hook'-shaped backbone structure in which the nearly extended conformation of the Val-Val-Gly-NH2 sequence is located under the folded conformation of the N-terminal Tyr-D-Ala-Phe-Glu sequence. The possible relationship between these conformational characteristics and the mu/delta-opioid receptor selectivities is discussed.

Case-control studies: matched controls or all available controls?

In order to realize the variation in the estimate of the odds ratio from case-control studies, results from individually matched sampling were compared with those from the analysis based on a large number of controls. The subjects were selected from those who visited Aichi Cancer Center Hospital from 1988 to 1990. Cases consisted of 251 male lung cancer patients aged 40-79 years. Age and year of visit matched controls were sampled independently 100 times and 5000 times from non-cancer male outpatients (cases to controls ratio: 1:1, 1:2, 1:3, and 1:4). As unmatched controls, all male non-cancer outpatients aged 40-79 years (4100 patients) were used. The smoking habit was adopted as an exposure variable. As logically expected, analysis based on 4100 male controls gave a steadier estimate than the matched analyses examined here, indicating that a matched sampling is not recommended when a large number of controls are available.

The effect of an SOD derivative (SM-SOD) administration in a burned rat model

To determine whether superoxide radicals may influence the pathogenesis of burn injury, we investigated the effects of a long-acting, site-directed superoxide dismutase derivative (SM-SOD) on the rats subjected to burn shock. Anesthesized animals were injected intravenously with either 2 ml/kg of saline or SM-SOD (10 mg/kg; dissolved in saline). After 30 min they were subjected to full-thickness burns of about 40% of total body surface area. The 7-day survival rate was significantly higher in the SM-SOD-treated animals than in the untreated controls. Also, administration of SM-SOD markedly inhibited the increase in the levels of thiobarbituric acid reactive metabolites, such as lipid peroxides in the plasma, lung and kidney, and the decrease in plasma protein levels particularly at the early stage of burn injury. These findings suggested that superoxide radicals may play a critical role in the pathogenesis following thermal injury.

Direct expression of a synthetic gene in Escherichia coli: purification and physicochemical properties of human initiation factor 4E

An artificial synthetic gene coding for human eIF-4E was cloned into an expression vector and direct expression was attempted in Escherichia coli [BL21(DE3) strain] under the control of T7 promoter. The active gene product which was induced in high yield (ca. 4 mg/100 ml) by isopropyl-beta-D-thiogalactopyranoside was purified to homogeneity by a two-step chromatographic procedure with a good yield (ca. 74%), and was confirmed to be recombinant human eIF-4E by amino acid composition and sequence analyses, isoelectric focusing, and absorption spectral measurements. The identity of three-dimensional structures between the recombinant and native human eIF-4Es was confirmed by CD and fluorescence measurements.

Detection of manganese superoxide dismutase mRNA in the theca interna cells of rat ovary during the ovulatory process by in situ hybridization

To determine the possible involvement of reactive oxygen species in ovulation, dynamic aspects of superoxide dismutase (SOD) isozyme were studied in the ovaries of rats by in situ hybridization histochemistry. Previously, mRNA levels of ovarian manganese superoxide dismutase (Mn-SOD) were reported markedly to increase whilst enzymic activity of Mn-SOD decreased during the ovulatory process after treating immature rats with 10 and 5 Units, respectively, of pregnant mare serum gonadotrophin (PMSG) and human chorionic gonadotrophin (HCG). Levels of Cu/Zn-SOD activity and Cu/Zn-SOD mRNA were reported to remain unchanged throughout ovulation. This increase in the Mn-SOD mRNA level was shown in the present study by in situ hybridization to be localized to the theca interna cells throughout the PMSG/HCG-induced ovulatory process. The observations suggest that the turnover rate of Mn-SOD but not Cu/Zn-SOD increases specifically in the mitochondria of these cells. SOD has been postulated to play important roles in steroidogenesis. The relationship is discussed between mitochondrial functions in steroid-secreting cells and superoxide radicals and related metabolite(s).