Is caloric restriction effective in preventing diabetes mellitus in the Otsuka Long Evans Tokushima fatty rat, a model of spontaneous non-insulin-dependent diabetes mellitus?

Studies were made on the effectiveness of caloric restriction in preventing the development of diabetes mellitus in a model rat (Otsuka-Long-Evans-Tokushima Fatty; OLETF) with non-insulin-dependent diabetes mellitus (NIDDM). Groups of 8 male OLETF rats aged 5 weeks were supplied with rat chow ad libitum (100% group) and 85% and 70% of the amount of food consumed by the 100% group (85% and 70% groups, respectively). The average weights of the 100%, 85% and 70% groups were 617, 536 and 450 g at 19 weeks of age and their abdominal fat deposits were 50, 38 and 21 g, respectively, at 22 weeks of age when they were killed. At 20 weeks of age, the cumulative incidences of diabetes mellitus in the 100%, 85% and 70% groups were 67%, 13% and zero, respectively. The plasma immunoreactive insulin (IRI) levels 60 and 120 min after oral glucose administration were significantly lower in the 70% group than in the other groups. In vivo insulin-stimulated glucose uptake measured by a euglycemic clamp technique, was significantly higher in the 70% group than in the 100% group. There was no significant difference in the glucose transporter 4 protein levels of skeletal muscles in the three groups, but the highest ratio of glucose transporter 4 in the plasma membrane to that in intracellular membranes was observed in the 70% group. Morphological studies on the pancreas of rats in the 100% group showed enlarged multilobulated fibrotic islets, whereas sections of islets of rats in the other groups appeared normal, though slightly enlarged. These results demonstrate that caloric restriction is effective in preventing NIDDM in diabetes-prone rats, probably due to increased insulin sensitivity.

[Applied DNA-DNA hybridization in determination of oral Streptococcus.]

Quantitative measurement of DNA-DNA hybridization is a new technique for determination of unknown bacteria.It is more valuable how to identify strains which is rare difference on phenotypic characteristics.It is important to resolve bactericial taxionmy and identify new strain.Four strain of Streptiococcus are determined by hybridization of DNA.Some technique problems are discussed.Such as purification,precision of DNA and temperature as well as time of DNA hybridization and standard of judgment.

Identification of neutrophil elastase as the proteinase in burn wound fluid responsible for degradation of fibronectin

To identify proteinases responsible for fibronectin degradation in the wound environment we studied wound fluid obtained from burn patients. Immunoblotting experiments showed that extensive degradation of fibronectin had occurred in some burn wound fluid samples, in which case intact fibronectin molecules were undetectable, and the largest fibronectin fragment was 116 kDa. The 116-kDa fragment as well as a smaller 90-kDa fragment contained the fibronectin cell binding domain. These burn-fluid samples degraded freshly added fibronectin. Activity of the fibronectin-degrading enzyme was blocked by a broad-spectrum serine proteinase inhibitor or by specific neutrophil elastase inhibitors but not by metalloproteinase inhibitors or inhibitors of trypsin-like or chymotrypsin-like serine proteinases. Enzyme activity also was neutralized by antibodies against human neutrophil elastase. Incubation of fibronectin with burn wound fluid or purified human neutrophil elastase generated similar fibronectin-degradation products. Finally, direct assay of burn-wound-fluid samples with a synthetic elastase substrate showed a correlation between fluid-phase elastase activity and fibronectin degradation. Based on these findings, we conclude that burn-wound-fluid elastase is responsible for extensive fibronectin degradation. Acute elevation of elastase did not appear to hinder normal wound repair.

Formation and structure of cross-linking and monomeric pyrrole autoxidation products in 2,5-hexanedione-treated amino acids, peptides, and protein

2,5-Hexanedione (2,5-HD) is the neurotoxic gamma-diketone metabolite of the industrial solvent n-hexane. Substantial evidence indicates that 2,5-HD reacts with neurofilament protein lysine epsilon-amines to yield 2,5-dimethylpyrrole adducts and that this reaction is critical to the mechanism of toxicity. Alkylpyrroles are susceptible to autoxidative dimerization, a process that has also been suggested as an obligatory step in 2,5-HD neuropathy. In the present study, we characterized pyrrole autoxidation products of a 2,5-HD-treated lysine analogue and of a model, lysine-containing dipeptide and examined mechanistic aspects of pyrrole-mediated protein cross-linking. Incubation of 2,5-HD with N alpha-acetyllysine or the dipeptide N alpha-acetylglycyllysine methyl ester in physiological buffer (pH 7.4) under oxidative conditions resulted in time-dependent formation of the N epsilon-pyrrole derivative and two major pyrrole autoxidation products, as demonstrated by HPLC, on-line thermospray MS, and UV photodiode array detection. An autoxidative pyrrole dimer containing a methylene bridge between C-2 of one pyrrole ring and C-3 of a second ring was characterized by thermospray MS and 1H-NMR spectroscopy. 13C-NMR spectroscopy provided evidence for an identical pyrrole-to-pyrrole bridge in autoxidized, pyrrolylated ribonuclease (RNase). MS analysis also revealed a second major product--a stable, oxygen-containing monomeric pyrrole derivative. This product exhibited a UV absorbance maximum (lambda max = 355 nm) consistent with extended conjugation. Polymerization of pyrrolylated acetyllysine was accelerated by persulfate, a free-radical initiator, and inhibited by ascorbate, an antioxidant.(ABSTRACT TRUNCATED AT 250 WORDS)

Multiplanar variations in the structural characteristics of cancellous bone

A quantitative serial sectioning technique and a video-imaging procedure were used to obtain precise (20-microns voxels, in a 5 mm x 6 mm x 7 mm test volume) digital images of lumbar vertebral cancellous bone specimens. Conventional stereological image analyses were performed on this data to determine multiplanar (bulk) and surface planar variations in cancellous structural properties. Based upon an error analysis of subgroups of the complete serial planar images, our findings suggest that, for a plane resolution of 20 microns, sectioning at an increment < or = 100 microns along an axis is necessary to obtain accurate data of bulk structural properties of cancellous bone. Planar structural variations obtained from the serial sections of cancellous bone revealed a high degree of complexity and heterogeneity of the bone architecture. Bone area centers deviated from the section centroid and showed a helical variation along the primary or superior--inferior loading axis of samples. In comparison with the base planes (perpendicular to the superior-inferior axis), the lateral planes (parallel to the superior-inferior axis) of spine samples showed smaller mean values of structural indices and a more oriented structure. This structural anisotropy may be related to the functional mechanical anisotropy of the samples.

Regulation of tetrahydrobiopterin biosynthesis in cultured dopamine neurons by depolarization and cAMP

Primary cultures containing embryonic rat brain mesencephalic or hypothalamic dopamine neurons were used to examine the effects of membrane depolarization and elevations of cAMP levels on tetrahydrobiopterin cofactor content. Initial studies showed that 24-h incubations with 8-bromo-cAMP or isobutyl methylxanthine increased cofactor levels in either culture system, whereas the stimulatory effects of forskolin or depolarization of membrane potential were only observed in cultures of hypothalamus. 8-Bromo-cAMP was found to increase cofactor content in a concentration-dependent manner, with increases observed up to 5 mM. The time course of the effect of 8-bromo-cAMP was biphasic. Over the short term, an increase of 50% in cofactor content at 2 and 5 h was detected. Over the long term, by 24-48 h, cofactor levels increased by between 100% and 300%. Studies of cofactor turnover indicated that the long-term increase was due to stimulation of tetrahydrobiopterin biosynthesis with no alteration in degradation rate. Inhibitors of gene transcription and translation prevented the long- but not short-term increase in cofactor content. Levels of GTP cyclohydrolase I mRNA were increased 7-10-fold following 5 h of incubation with 8-bromo-cAMP. Tetrahydrobiopterin biosynthesis within cultured dopamine neurons of the hypothalamus and mesencephalon thus appears to be regulated by a cAMP-dependent mechanism involving enhanced gene expression of enzyme(s) involved in cofactor biosynthesis.

Effects of specimen load-bearing and free surface layers on the compressive mechanical properties of cellular materials

The influence of load-bearing surface layers on Young's modulus was determined for cancellous bone and polyurethane foam specimens of three different heights cut from each material: 16, 9, and 5 mm for bone specimens (cross-sectional area A = 81 mm2) ranging in density from 0.04 to 0.32 g cm-3; 20, 10, and 5 mm for foam specimens (A = 100 mm2) ranging in density from 0.064 to 0.64 g cm-3. The compressive elastic modulus of the 5 mm bone specimens was significantly smaller (42%) than that of the 16 mm bone specimens. A similar change in elastic modulus was also observed for the foam specimens, but the height effect diminished in a relatively linear manner as the foam density increased. For a height change from 20 to 5 mm, the foam modulus difference ranged from a 41% decrease for the lowest density specimens (p = 0.064 g cm-3) to an insignificant change (< 1.8%) for the highest foam density specimens (p = 0.64 g cm-3). The specimen height effect on elastic modulus was hypothesized to result from a higher deformation (compliance) of the cellular materials in the load-bearing or contacting surface layer than in the bulk. A mathematical formula was derived to predict the variation in measured elastic modulus (E) caused by the contacting surface layer modulus (Ecs) to bulk modulus (Eb) ratio (Y = Ecs/Eb) and contacting surface layer height (hcs) to sample height (h) ratio (t = hcs/h): E/Eb = Y/[Y(1-t)+t]. Predicted differences in the measured modulus associated with graduated specimen heights were verified experimentally by regional strain measurements of the foam and bone samples using an optical microscope. The influence of free-surface layers was also determined for the foam specimens with cross-sectional areas 1.21 and 10 times the load-bearing area of a load platen, but the measured differences were small (< 10%) compared to that of the load-bearing surface layer influence. In future compressive mechanical testing of cellular materials, specimens < 10 mm in height should be avoided, particularly specimens with low bulk density or high porosity.

[Effects of "moist burn ointment--mei bao" on production of IL-2 in burn rats and its clinical problems]

Since "Mei Bao" has been used in clinical treatment of burn wounds, there is a diversity of opinions concerning its effect. We carried out a series of experiments to observe its therapeutic effect, bacteriostatic property, and its effect on production of IL-2 in thermally injured rats. These results indicate that obvious infection occurred after its use on burn wounds and healing is delayed. Hyperplastic scars accompanying with deformity appeared after healing. The cost of treatment is high. There is no improvement in immune reaction, and no bacteriostatic property is observed.

The value of hepatitis B x antigen as a prognostic marker in the development of hepatocellular carcinoma

Chronic infection with hepatitis-B virus (HBV) is associated with high risk for the development of hepatocellular carcinoma (HCC). Several studies have implicated that the X gene product(s) of HBV are important to the pathogenesis of HCC. This study tests the hypothesis that immunohistochemical detection of hepatitis B x antigen (HBxAg) is closely associated with HCC. The patterns of HBxAg were determined by staining in tumor and non-tumor liver sections from 30 Chinese patients with HBV-associated HCC, and the results were compared with other markers of infection. HBxAg was the most prevalent marker of HBV infection both in tumor and in non-tumor tissues of HCC patients, as compared with the hepatitis-B surface and core antigens. This pattern was observed among carriers as well as several patients who were HBsAG- in serum. The HBxAg staining results were validated by Southern blotting with an X-region probe and by Western blotting with anti-HBx. These results suggest that the persistence of HBxAg is important to the pathogenesis of early HCC and that HBxAg expression in the liver during chronic HBV infection may be an important prognostic marker for the development of HCC.

Capillary electrophoresis of abnormal hemoglobins associated with alpha-thalassemias

Capillary electrophoresis was evaluated for separation of hemoglobin species associated with alpha-thalassemias, and for identification of hemoglobin variants commonly found in the same human populations. Separation of hemoglobins was achieved using capillary isoelectric focusing with chemical mobilization; visible-wavelength absorbance detection was used to identify hemoglobins against a background of nonheme-containing proteins. This technique could easily differentiate hemoglobins Bart's and H (associated with alpha-thalassemias) from hemoglobin variants. Analysis of globin chains derived from intact hemoglobins was performed by free zone capillary electrophoresis under denaturing conditions. This technique was useful for distinguishing Hb Bart's and Hb H, and for confirming the identity of hemoglobin variants.

Detection of the actin scavenger system in burn wound fluid

The intravascular actin scavenger system depolymerizes and sequesters actin released after tissue injury. Studies were carried out to determine if this system is active in the extracellular space during wound repair. Using burn wound fluid as a noninvasive means for analyzing the wound environment, we measured actin accumulation and actin complex formation with the plasma proteins responsible for scavenger function. Actin at concentrations as high as 0.25 mg/ml ( approximately 5 micromol/L) was found in burn wound fluid samples from 9 of 11 patients. Wound fluid also contained the two plasma proteins that bind actin-gelsolin (both plasma and cytoplasmic forms) and Gc protein. Because actin in wound fluid was complexed with gelsolin and Gc protein, we conclude that the components of the actin scavenger system are functional in wound tissue. In addition, proteolysis of gelsolin, but not actin or Gc protein, appeared to occur at the wound site. Gelsolin proteolysis was accompanied by the appearance of 49 kd gelsolin fragments, and wound fluid samples lacking intact gelsolin also contained high metalloproteinase levels.

Hepatitis B x antigen and p53 are associated in vitro and in liver tissues from patients with primary hepatocellular carcinoma

To test the hypothesis that hepatitis B x antigen (HBxAg) binds to the tumor-suppressor protein p53, immunoprecipitation was carried out with monoclonal anti-x or monoclonal anti-p53 using radiolabeled HBxAg and p53 made by in vitro translation. The results showed that anti-p53 specifically immunoprecipitates HBxAg only in the presence of p53 and that anti-x specifically immunoprecipitates p53 only in the presence of HBxAg. to determine whether HBxAg binds p53 in vivo, immunoprecipitation and Western blot analysis of liver samples from 10 hepatitis B virus (HBV)-infected patients with primary hepatocellular carcinoma (PHC) were carried out. A protein band at 53,000 daltons that specifically immunoprecipitated with a monoclonal anti-x was identified as p53 by Western blotting with a monoclonal anti-p53. Anti-p53 specifically immunoprecipitated bands of 28,000, 17,000 and 13,000 daltons, which were identified as HBxAg polypeptides by Western blotting with anti-HBx. These findings suggest that HBxAg binds to p53 and that this association is important to the development of PHC.

Beyond Section 504: satisfaction and empowerment of students with disabilities in higher education

College and university students with disabilities were surveyed to determine their levels of satisfaction with accessibility, special services, and accommodations at their schools. In addition, students were requested to identify barriers to postsecondary education, improvements in services, and other concerns. Respondents generally expressed satisfaction with the services that they had received. However, the majority indicated that they had encountered barriers to their education, including a lack of understanding and cooperation from administrators, faculty, staff, and other students; lack of adaptive aids and other resources; and inaccessibility of buildings and grounds. Recommendations were made for improving the delivery of services and self-advocacy of students with disabilities.

Effects of some opiates and opioid peptide eyedrops on ocular melatonin regulation in rabbits

Levels of melatonin in rabbit eye tissues were detected by radioimmunoassay. Solutions of met-enkephalin, leu-enkephalin, alpha-endorphin and beta-endorphin were given topically. Met-Enkephalin and alpha-endorphin lowered levels of melatonin in the iris, iris root-ciliary body, retina and choroid; leu-enkephalin raised levels in the retina and lowered them in other tissues. beta-Endorphin only lowered levels in the iris root-ciliary body. DAGO (a mu agonist) given i.v. lowered levels of melatonin in the iris, iris root-ciliary body and retina. The delta and sigma agonists given i.v. only lowered levels in the iris root-ciliary body, and a kappa agonist given i.v. raised levels in the ciliary body. No opiate binding sites could be detected in the rabbit iris or iris root-ciliary body for any class of receptor. Our data suggest opioids may be useful for treating glaucoma.

Differential metabolism of tetrahydrobiopterin in monoamine neurons: a hypothesis based upon clinical and basic research

This chapter has attempted to describe and integrate some of the clinical and basic research that support our hypothesis that the metabolism of BH4 is normally heterogeneous across different populations of monoamine-containing neurons. Based upon this hypothesis, there may now be reason to support the idea that certain neuropsychiatric illnesses, which are though to be the result (at least in part) of altered monoamine metabolism, might find their roots in an abnormal metabolism of BH4 within specific monoaminergic cell groups. Such a specific dysfunction might not be apparent in the rest of the brain or peripheral nervous system, thereby being difficult to detect. Perhaps the application of molecular biological techniques to studies of BH4 metabolism in man will shed new light on these problems.

Analysis of alkylpyrrole autoxidation products by high-performance liquid chromatography with thermospray mass spectrometry and UV photodiode-array detection

A method employing high-performance liquid chromatography with thermospray mass spectrometry (TSP-MS) and photodiode-array detection was developed and applied to the analysis of autoxidation products of 2,5-dimethyl-N-alkylpyrroles in aqueous solution under air or 18O2. Numerous oxidation products were separated, characterized and categorized, primarily as (1) non-polar oligomers without incorporated oxygen, and (2) polar, oxygen-containing monomers. Kinetic studies showed that oligomerization was the dominant autoxidation pathway, with production of unstable dimers and trimers and, ultimately, a high-molecular-mass sediment. TSP-MS together with UV and proton nuclear magnetic resonance spectral data revealed that both the dimer and trimer contained a novel methylene bridge. These results suggest that this method is suitable for the analysis of alkylpyrrole autoxidation products that may be relevant to hexane neuropathy and products that are responsible for the instability of fuels in storage.