Three RFLPs defining a haplotype associated with the common mutation in human medium-chain acyl-CoA dehydrogenase (MCAD) deficiency occur in Alu repeats

Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is a common inborn error of fatty-acid oxidation and may cause sudden infant death. Previous studies revealed that (i) homozygosity for an A-to-G mutation at nucleotide 985 of the mRNA coding region (A985G) is an extremely common cause of MCAD deficiency and (ii) MCAD deficiency is strongly associated with a particular haplotype for RFLPs for BanII, PstI, and TaqI. TaqI allele 2 is always associated with the A985G mutation in human MCAD deficiency. In this study, we have delineated the molecular basis of the RFLPs for PstI, BamHI, and TaqI in the human MCAD gene. Our results prove that the three RFLPs are caused by point mutations in the 8 kb of DNA encompassing exons 8-10 of the human MCAD gene. The TaqI polymorphism is caused by a C-to-A substitution 392 bp upstream of the exon 8, and the PstI and BamHI polymorphisms are due to T-to-C and G-to-A substitutions, respectively, which are 727 and 931 bp downstream of exon 10 respectively. All three RFLPs lie within Alu repetitive sequences. Comparison of intronic sequences immediately following exon 10 from two normal individuals with different haplotypes showed that this region contains densely packed Alu repeats and is highly polymorphic. Our results are consistent both with a founder effect as the cause of the high prevalence of a single (A985G) mutation in MCAD deficiency and with its association with a particular haplotype for these intragenic RFLPs.

Identification of PP1 catalytic subunit isotypes PP1 gamma 1, PP1 delta and PP1 alpha in various rat tissues

cDNA clones for 4 rat protein phosphatase 1 (PP1) catalytic subunit isotypes, PP1 alpha, PP1 gamma 1, PP1 gamma 2 and PP1 delta, were isolated (K. Sasaki et al., Jpn. J. Cancer Res. 81, 1272-1280, 1990). Antibodies were raised to determine the physiological functions of 4 isotypes. Among these isotypes, the PP1 gamma 2 protein was detected specifically in rat testis (H. Shima et al., Adv. Prot. Phosphatases, vol. 7, in press). On the other hand, PP1 gamma 1, PP1 delta and PP1 alpha were detected as 36kDa, 37kDa and 38kDa proteins in several rat organs by immunoblot analysis. All three isotypes were found in both soluble and particulate fractions. PP1 gamma 1 was predominant in the brain and PP1 delta in the brain, lung and small intestine, but the levels of both were low in the liver and muscle. It became evident that PP1 alpha was not a predominant isotype in any tissue examined.

Inactivation of synovial fluid alpha 1-antitrypsin by exercise of the inflamed rheumatoid joint

alpha 1-Antitrypsin (alpha 1AT) is known to be oxidised by reactive oxygen species both in vitro and in vivo, leading to its inactivation. We report here that synovial fluid (SF) alpha 1AT is inactivated during exercise of the knee-joints of rheumatoid arthritis (RA) patients. Sequential SF sampling from exercised RA patients showed a marked decrease in the mean activity of alpha 1AT after exercise with no change in the molecular forms of alpha 1AT. No such inactivation was found in the control (continuously resting) RA patients. We suggest that oxidation may contribute to alpha 1AT inactivation as a consequence of 'hypoxic-reperfusion' injury after exercise of the inflamed joint.

A microscopic model for lipid/protein bilayers with critical mixing

A statistical mechanical lattice model is proposed to describe the phase diagram of phospholipid bilayers with small transmembrane proteins or polypeptides. The model is based on the extended Pink-Green-Chapman model (Zhang et al. (1992) Phys. Rev. A 45, 7560-7567) for pure lipid bilayers which undergo a first-order gel-fluid phase transition. The interaction between the lipid bilayer and the protein or polypeptide is modelled using the concept of hydrophobic matching. The phase diagram has been derived by computer-simulation techniques which fully account for thermal density fluctuations and which operate on the level of the free-energy thereby permitting an accurate identification of the phase boundaries. The calculations predict a closed loop of gel-fluid coexistence with a lower critical mixing point. Specific-heat traces across the phase diagram are also presented. The theoretical results for the phase diagram, the specific-heat function, and the transition enthalpy are related to recent experimental measurements on phospholipid bilayers mixed with synthetic transmembrane amphiphilic polypeptides or with gramicidin A.

Circadian regulation of iodopsin gene expression in embryonic photoreceptors in retinal cell culture

A circadian clock regulates a number of diverse physiological functions in the vertebrate eye. In this study, we show that mRNA for the red-sensitive cone pigment, iodopsin, fluctuates with a circadian rhythm in chicken retina. Transcript levels increase in the late afternoon just prior to the time of cone disc shedding. Furthermore, iodopsin mRNA levels are regulated similarly by a circadian oscillator in primary cultures of dispersed embryonic chick retina. Nuclear run-on experiments show that the circadian regulation of iodopsin transcript abundance occurs at the level of gene transcription. Our results provide a demonstration of clock-regulated gene expression in a vertebrate preparation maintained in cell culture.

Determination of amide hydrogen exchange by mass spectrometry: a new tool for protein structure elucidation

A new method based on protein fragmentation and directly coupled microbore high-performance liquid chromatography-fast atom bombardment mass spectrometry (HPLC-FABMS) is described for determining the rates at which peptide amide hydrogens in proteins undergo isotopic exchange. Horse heart cytochrome c was incubated in D2O as a function of time and temperature to effect isotopic exchange, transferred into slow exchange conditions (pH 2-3, 0 degrees C), and fragmented with pepsin. The number of peptide amide deuterons present in the proteolytic peptides was deduced from their molecular weights, which were determined following analysis of the digest by HPLC-FABMS. The present results demonstrate that the exchange rates of amide hydrogens in cytochrome c range from very rapid (k > 140 h-1) to very slow (k < 0.002 h-1). The deuterium content of specific segments of the protein was determined as a function of incubation temperature and used to indicate participation of these segments in conformational changes associated with heating of cytochrome c. For the present HPLC-FABMS system, approximately 5 nmol of protein were used for each determination. Results of this investigation indicate that the combination of protein fragmentation and HPLC-FABMS is relatively free of constraints associated with other analytical methods used for this purpose and may be a general method for determining hydrogen exchange rates in specific segments of proteins.

A sequential study on the use of the cytokinesis-block micronucleus method in mouse splenocytes

Several known clastogens and mutagens have been tested for their ability to induce micronuclei (MN) using the cytokinesis-block method in mouse splenocytes. The chemicals were harringtonine, cisplatin, cytosine arabinoside, vincristine sulfate, colchicine, potassium chromate, methyl methanesulfonate and 2-acetylaminofluorene. All chemicals tested induced a dose-dependent increase in MN and a delay in cell-cycle progression. The results suggest that the cytokinesis-block micronucleus method in mouse splenocytes is reliable, economical and sensitive enough for detecting mutagenic agents in vivo and in vitro.

Expression of integrin alpha 1 beta 1 is regulated by nerve growth factor and dexamethasone in PC12 cells. Functional consequences for adhesion and neurite outgrowth

PC12 cells respond to nerve growth factor by differentiating into sympathetic neuron-like cells that employ the integrin alpha 1 beta 1 to attach to, and extend neurites on, substrata coated with collagen or laminin. In one PC12 subline, PC12i, prolonged treatment with nerve growth factor results in a marked increase in synthesis of alpha 1 subunits and in the level of alpha 1 mRNA, with a corresponding increase in alpha 1 beta 1 expressed on the cell surface. These changes are accompanied by substantial increases in initial cell attachment to collagen and in the fraction of neurite-bearing cells and average neurite length. Integrin beta 1-subunits are constitutively expressed, so that alpha 1 synthesis controls the amount of alpha 1 beta 1 heterodimer expressed on PC12i cells. Acidic fibroblast growth factor also induces alpha 1 beta 1 in PC12i cells, with consequent enhancement of neurite outgrowth; treatment with epidermal growth factor or dibutyryl cyclic AMP does not have these effects. Another subline, PC12c, expresses high levels of alpha 1 mRNA and alpha 1 protein constitutively. With or without nerve growth factor pretreatment, these cells adhere well to collagen and a majority extend neurites when replated in the presence of nerve growth factor. Dexamethasone treatment of PC12c cells reduces expression of alpha 1 mRNA and alpha 1 protein, with consequent reduction in attachment to collagen. In both sublines, then, there is a direct relationship between the level of a specific matrix receptor and cell-matrix adhesion. Moreover, our results suggest that induced expression of this matrix receptor is an essential aspect of the regulation of neurite extension by nerve growth factor in PC12i cells.

Crystal parameters of an alcohol dehydrogenase from the extreme thermophile Thermoanaerobium brockii

A bacterial thermophilic alcohol dehydrogenase which is stable and active at 85 degrees C, has been crystallized by vapor diffusion from solutions of polyethylene glycol. A monoclinic crystal form diffracts to 2.8 A resolution and belongs to space group C2 with unit cell dimensions a = 139.0 A, b = 137.4 A, c = 80.9 A and beta = 93.23 degrees. The asymmetric unit contains four molecules which exhibit 222 point symmetry. A second crystal form is orthohombic, space group P2(1)2(1)2 with unit cell dimensions a = 168.0 A, b = 123.0 A, c = 80.0 A, and it diffracts to 3.2 A resolution.

[The number, distribution and effects of interleukin-2 receptor and CD4 antigens in benign and malignant lymphoproliferative diseases]

An analysis of immunophenotypes was made in benign and malignant lymphoproliferative diseases (35 cases) and short cultured lymphocytes of chronic tonsillitis (15 cases). The number, distribution and variation of interleukin-2 receptor (IL-2R, CD25) and CD4 positive cells in the above lesions were studied. The results showed that (1) there were more or less IL-2R+ and CD4+ cells presented in the tissues of benign lymphoproliferative lesions; (2) IL-2R antigen was also presented in some tumor and non-tumor cells with CD4+ reaction but it was not found in the cells with CD1+ or/and CD8+ reactions; (3) IL-2R and CD4 antigens were expressed in the proliferated lymphocytes stimulated by PHA. Although IL-2R antigen is not a specific marker to certain types of lymphocytes, it has some relations with immunophenotypes of lymphocytes. The functions and effects of IL-2, IL-2R and helper T lymphocytes were also discussed.

[Pharmacokinetics model for targeted drug delivery systems]

Analyzing the observed phenomena and the data collected in research, we developed a multi-compartment linear recirculation model for targeted drug delivery systems and figured out the function formulas of the drug concentration-time in blood and target organ by computing. According to this model, the drug concentration-time curve for the target organ can be plotted with reference to the data on blood; the pharmacokinetics parameters of the target organ can also be obtained. We further detected the practicability of the model by using the curves of drug concentration-time in blood and target organ (liver) of liver-targeting nanoparticles obtained from animal tests. Based on the liver drug concentration-time curve calculated by the function formula of target organ and the statistical moment, the pharmacokinetics behaviour of the target organ (liver) was analysed and the pharmacokinetics parameters of liver were obtained. We suggest that the "relative targeting index" be used for quantitative evaluation of the targeted drug delivery system.

Thymic carcinoid tumor--a report of 7 cases

The thymic carcinoid tumor is a rare neoplasm which is often clinically misdiagnosed as thymoma. But the two differ in origin, biological behavior, accompanying syndromes, pathological features, and prognosis. The characteristics of the thymic carcinoid tumor are: difficulty in diagnosis, high malignancy, frequent recurrence and extrathoracic metastasis over a prolonged period postoperatively. Complete surgical resection of original and recurrent tumors is the important treatment. Microscopic, electron microscopic and immunohistochemical examinations may be required in making an accurate pathological diagnosis. This paper reports 7 cases of thymic carcinoid tumor.

Development of PVEP in infants and children

The development of components of VEP was studied in 150 infants and children between 2 weeks and 9 years of age participated as subjects. Ten adult subjects, 25 to 35 years of age were also studied. The results indicated that the VEP had a simple wave form, consisting of only a slowly rising positive wave to 140', 70' and 35' checks from infants of 2 to 8 weeks following birth. P1 wave appeared in response to 17.5' check stimulus at 10 weeks following birth. The latencies of P1 components shortened dramatically from infants of 2 to 4 months and the latencies of low spatial frequencies (140' and 70' checks) from infants at 4 months of age reached adult level but P1 latency of medium spatial frequency (35' check) did not reach adult level until age of 4 years. The latency of P1 component of high spatial frequency was matured by the end of 9 years of age. The development of P1 waves from both eyes was parallel in normal infants and children. The amplitudes N1P1 and P1N2 from infants and children with 2 months to 9 years were not affected by the age and significantly higher than those of adults group by 2 to 3 factors. Based on the results of our research, three phases were found in the development of the visual function in infants and children. The first phase was up to 4 months after birth, and characterized by the maturation of the low spatial frequencies.(ABSTRACT TRUNCATED AT 250 WORDS)

[A study on classification of Xanthomonas by isoelectric focusing]

Studying Xanthomonas strains of 4 species and 29 pathovars by isoelectric focusing, it was shown that the protein patterns were very different among the species and pathovars. Through cluster analysis of IEF date, it was found that the protein pattern differences among certain pathovars were no fewer than that among the species. It revealed that some pathovars could become to be species. There were few differences of 6 protein bands among X. campestris pv. cerealis, X. campestris pv. undulosa and X. campestris pv. hordei which cause bacterial black cheff, so the classification of the three pathovars need to be re-considered. It also showed that isoelectric focusing could be used to classify Xanthomonas below species.

Uptake of technetium-99m-teboroxime in cultured myocardial cells: comparison with thallium-201 and technetium-99m-sestamibi

The effects of metabolic inhibition on the uptake of 99mTc-teboroxime were assessed in cultured myocardial cells and compared with 201Tl and 99mTc-sestamibi. Metabolic impairment was induced by cyanide (CN), a blocker of the mitochondrial respiratory chain, iodoacetate (IAA), an inhibitor of the glycolytic pathway, and ouabain, an inhibitor of Na(+)-K+ sarcolemmal ATPase. Cellular viability was appreciated by the trypan blue exclusion method. The effects of low temperature and of cellular death resulting from osmotic lysis were also assessed. Net cellular uptake of the radiotracers and the amount of proteins in the culture dishes were measured. All experiments were performed in parallel with control conditions and the results were expressed relatively to the control values. Teboroxime uptake was clearly decreased at low temperature (29.6% +/- 2.2% at 0 degree C, p < 0.001), while metabolic inhibition or osmotic lysis had no definite effect. The uptake of 201Tl and sestamibi was severely diminished in the presence of a mixture of 5 mM CN and 0.1 mM IAA, but 201Tl was less resistant than sestamibi (13.7% +/- 0.3% and 73.5% +/- 3.3%, respectively, after 1 hr of preincubation, p < 0.001 for both). Uptake of both tracers was very low in the presence of dead cells (12.1% +/- 1.3% for 201Tl and 4.1% +/- 0.2% for sestamibi, p < 0.001 for both). Ouabain had a detrimental effect only on 201Tl uptake at doses higher than 100 microM. Of these three currently available coronary blood flow imaging agents, teboroxime shows the lowest sensitivity to metabolic impairment.

Synthesis of N-(4'-pyridoxyl)sphingosine and its uptake and metabolism by isolated cells

N-(4'-pyridoxyl)sphingosine was synthesized and characterized as a stable compound for specialized delivery of a bioactive lipid. It was found to be facilely taken up by hepatocytes although by a mechanism more typical for lipids than the one used by natural vitamin B6. Some of the N-(4'-pyridoxyl)sphingosine was metabolically acted upon inside the cell to release pyridoxal 5'-phosphate and sphingosine, but formation of pyridoxal 5'-phosphate from the synthetic compound was poor compared with natural vitamin forms of B6, which may partly be due to entrapment within cell membranes and to constraints at the level of cytosolic pyridoxal kinase which is responsible for phosphorylation of the vitamin. Unlike the parent long-chain base, the B6 conjugate was not particularly cytotoxic. Furthermore, the compound was neither an activator nor inhibitor of the respiratory burst of human neutrophils. These findings identify N-(4'-pyridoxyl)sphingosine as an interesting tool for studies of the cellular transport, metabolism, and functions of both vitamin B6 and sphingosine.

A perturbation method for finite element modeling of piezoelectric vibrations in quartz plate resonators

When the piezoelectric stiffening matrix is added to the mechanical stiffness matrix of a finite element model, its sparse matrix structure is destroyed. A direct consequence of this loss in sparseness is a significant rise in memory and computational time requirements for the model. For weakly coupled piezoelectric materials, the matrix sparseness can be retained by a perturbation method which separates the mechanical eigenvalue solution from its piezoelectric effects. Using this approach, a perturbation and finite element scheme for weakly coupled piezoelectric vibrations in quartz plate resonators has been developed. Finite-element matrix equations were derived specifically for third-overtone thickness-shear, SC-cut quartz plate resonators with electrode platings. High-frequency piezoelectric plate equations were employed in the formulation of the finite element matrix equation. Results from the perturbation method compared well with the direct solution of the piezoelectric finite element equations. This method will result in significant savings in the computer memory and computational time. Resonance and antiresonance frequencies of a certain mode could be calculated easily by using the same eigenpair from the purely mechanical stiffness matrix. Numerical results for straight crested waves in a third overtone SC-cut quartz strip with and without electrodes are presented. The steady-state response to an electrical excitation is calculated.

Development of a mouse intestinal transplantation model

We have recently developed a mouse intestinal transplantation model. The proximal segment of donor jejunum is transplanted into the recipient in a heterotopic position. End-to-side anastomoses are performed between donor aorta and recipient aorta and between donor portal vein and recipient inferior vena cava. Mortality rates were initially high due to shock, arterial thrombosis, and postoperative sepsis. Refinements in surgical techniques reduced these complications, resulting in a high rate of success. Important technical factors included (1) minimizing ischemic injuries to the graft in both the donor and the recipient, (2) using an aortic patch and elliptical aortotomy for anastomosis, (3) administering large volumes of crystalloid to maintain normal blood pressure during the donor and recipient surgeries, and (4) using broad-spectrum antibiotics as postoperative prophylaxis. The mice with isografts had normal intestinal function and histology when they were sacrificed 1 month after surgery. This new model of small bowel transplantation will be a useful tool to study the immunology of intestinal grafting at the molecular level.

Insidious errors in dipole localization parameters at a single time-point due to model misspecification of number of shells

Insidious errors (unexpected and difficult-to-detect under usual conditions) were found using a single time-point dipole localization method, when two dipoles were simultaneously active and there was misspecification of the number of shells (usually intended to mimic the conductivity differences of the brain, skull, and scalp). The errors involved all dipole parameters (i.e., location, orientation, and magnitude). Potentials at 65 "electrode" locations on the surface of a 3-shell sphere were computed for dipoles of known location, orientation, and magnitude. These "maps" were then used to compute the best-least-squares-fit of the surface potentials based upon dipole parameters in a 1-shell sphere when either one or two dipoles were active. The dipole parameters were often significantly different when computed with two equal-magnitude dipoles active, compared with only one dipole, with location errors of 0-36 mm, orientation errors of 0-63 degrees, and magnitude errors of 2-98%. When the two dipole magnitudes were not the same, the errors in the computed dipole parameters were even larger. All these errors occurred when the LSE (least-square-error) was small and at or near minimum. Moreover, location errors increased as LSE decreased over iterations. These errors generally occur because the fitted dipole parameters under different potential maps do not obey the superposition law when there is shell model misspecification, which is also the reason that presently used "correction" methods cannot satisfactorily remove these errors from the analyses. This problem must be dealt with when analyzing evoked response "maps" from simultaneously active generators, if correspondence to anatomy and physiology is desired.

Developing a stable bilateral model of parkinsonism in rhesus monkeys

The non-human primate models of Parkinson's disease which have been developed using the neurotoxin MPTP (1-methyl-4-phenyl-1,2,3,6 tetrahydropyridine) have proven to be either unstable or variable, or to display only a limited subset of parkinsonian features. The present study examined a new two-stage lesion approach in which MPTP was administered via the carotid arteries. The first infusion through one artery produced a hemiparkinsonian state and was followed several months later by a second MPTP infusion into the contralateral carotid artery to induce bilateral parkinsonism. Animals receiving lesions were evaluated using a battery of tests which included a monkey parkinsonism rating scale, a movement time-task and continuous monitoring of home cage activity. All animals monitored showed significant decreases in activity levels of up to 95% following the second lesion. These decreased activity levels remained stable throughout the observation period of up to 12 months postlesion. In addition to the decreased home cage activity, bilaterally lesioned animals displayed bilateral parkinsonian features including akinesia, bradykinesia, rigidity, tremor and balance and gait disturbances which were stable, following an acute period of up to 45 days, for the remainder of the study. Administration of levodopa increased activity levels and reduced motor dysfunctions. Thus, a two-stage bilateral lesion approach, utilizing the neurotoxin MPTP, appears to provide a less variable and relatively stable model of bilateral Parkinson's disease in nonhuman primates. Treated animals display the cardinal features of parkinsonism and respond appropriately to the standard antiparkinsonian drug, levodopa.

Pyridoxine-5'-beta-D-glucoside competitively inhibits uptake of vitamin B-6 into isolated rat liver cells

Uptake of pyridoxine-5'-beta-D-glucoside by freshly isolated rat liver cells was studied at a concentration (0.5 mumol/L) approximating the physiological range of vitamin B-6 by using a membrane filtration method. Unlabeled pyridoxine glucoside was found to competitively inhibit the uptake of [4'-3H]pyridoxine but have no detectable effect on the uptake of D-[1-3H]glucose by hepatocytes. The uptake of [3H]pyridoxine glucoside by isolated rat liver cells was very similar to the uptake of [3H]pyridoxine with Kt = 13.8 mumol/L (6.3 mumol/L for pyridoxine) and Vmax = 82 pmol/(10(6) cells.min) [28 pmol/(10(6) cells.min for pyridoxine)]. The results of this study indicate that pyridoxine glucoside uses the same transport system as does pyridoxine. Upon entry to the cell, pyridoxine glucoside undergoes hydrolysis to release pyridoxine, which is the rate-limiting step in metabolism of this beta-glucoside.

High field proton NMR investigations of the metabolic profiles of multidrug-sensitive and -resistant leukaemic cell lines: evidence for diminished taurine levels in multidrug-resistant cells

High field proton (1H) nuclear magnetic resonance (NMR) spectroscopy has for the first time been employed to investigate and compare the metabolic profiles of vinblastine-sensitive and -resistant T-lymphoid leukaemic cell lines (CCRF-CEM and CEM/VLB100 respectively) and evidence is presented for a significantly lower taurine content in the CEM/VLB100 resistant subline when expressed relative to that of its drug-sensitive parental counterpart. These data suggest differences in the nature and relative involvements of taurine biosynthetic pathways between the two cell lines, a phenomenon that may be related to their differing sensitivities towards chemotherapeutic agents such as adriamycin which promote the generation of cytotoxic reactive oxygen species (ROS) in vivo. However, the 1H NMR data obtained provided no evidence for an increased metabolic consumption of hypotaurine (a metabolic precursor of taurine with powerful .OH radical scavenging properties) in CCRF-CEM cells since differences observed in the hypotaurine: taurine concentration ratio between the drug-sensitive and -resistant cell lines were not statistically significant. Furthermore, hypotaurine is unlikely to compete with alternative endogenous .OH radical scavengers present such as lactate since its level in either of the two cell lines investigated (ca. 6.0 x 10(-8) mol./10(8) cells) is insufficient for it to act as an antioxidant in this context. The biochemical and therapeutic significance of these results are discussed.

Substrates and the regulation of hepatic glycogen metabolism

Glycogen metabolism is a complex process which depends on the metabolic circumstances and the hormonal milieu. In this overview an intriguing new possibility has been emphasized--the possible central role of lactate in coordinating, with glucose, the net synthesis of glycogen. Since lactate changes acutely under many physiological circumstances, it would be a logical candidate for a signal which communicates to the liver the metabolic states of the periphery. It would then acutely determine the synthetic rate of glycogen synthesis within the range determined by the glucose concentrations which in turn could be said to reflect the nutritional state of the system. Interestingly, after oral glucose loading, portal glucose levels would be about 25% higher (Radziuk et al., 1978) relative to arterial. As seen from Figs 8 and 9 however the glycogen synthetic rate appears very sensitive to glucose (at a given lactate uptake). Everything else being assumed equal therefore, more glycogen would be synthesized than during intravenous loading with an equivalent peripheral concentration. This is indeed the case (Shulman and Rossetti, 1989). On the other hand, during equivalent loads, peripheral glucose levels are higher and the same quantity of glycogen is synthesized (Radziuk, 1989a, 1989b). If lactate is typical of other glucogenic substrates, then it is also logical that mixed meals with higher levels of portal substrate would maximize glycogen synthetic rates. Similarly, in diabetes where hyperglycemia and hyperlactatemia prevail, gluconeogenesis plays a predominant role in glycogen synthesis (Giaccari and Rossetti, 1992).(ABSTRACT TRUNCATED AT 250 WORDS)

[Chemical constituents from the bark of Hibiscus syriacus L]

Seven constituents (I-VII) were isolated from the bark of Hibiscus syriacus and identified as nonanedioic acid (I), suberic acid (II), 1-octarcosanol (III), beta-sitosterol (IV), 1,22-docosanediol (V), betulin (VI) and erythrotriol (VII). VII was obtained from the plant for the first time, I, II, III and VI were isolated from Malvaceae plants for the first time.

Dietary fish oil delays puberty in female rats

Marine oils contain eicosapentaenoic acid, a fatty acid that competes for cyclooxygenase and reduces the synthesis of dienoic prostanoids including prostaglandin E2 (PGE2). Since PGE2 plays an important role in the estrogen-stimulated release of hypothalamic GnRH on proestrus, it was postulated that a diet containing fish oil would delay first ovulation through inhibitory effects on GnRH release. Thirty, 22-day-old female Sprague-Dawley rats were fed a diet containing fish oil ad libitum. Controls were pair-fed an identical diet with the substitution of safflower oil as the dietary fat. All rats were killed on the morning of first metestrus after vaginal opening and the display of an estrous smear(s). Fish oil feeding did not affect growth as indicated by the lack of an observed effect on body weights or femur lengths. On the other hand, pituitary, ovarian, and uterine weights were significantly lower in the rats fed fish oil (p < 0.001). The age at first estrus of the rats fed fish oil was significantly increased compared with the controls (42.9 +/- 1.0 vs. 36.1 +/- 0.3 days; p < 0.001), whereas the number of rats with corpora lutea (CL), as well as the number of CL per ovary (2.3 +/- 0.4 vs 4.8 +/- 0.6 for controls; p < 0.001) was significantly reduced by fish oil feeding. GnRH concentration in the preoptic area/hypothalamus was significantly increased in the fish oil-fed rats (21.4 +/- 4.0 pg/mg vs. 7.6 +/- 2.2 pg/mg for controls; p < 0.01); radioimmunoassable hypothalamic PGE2 was concomitantly reduced (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of multi-glycosides of Tripterygium wilfordii Hook f. (GTW) on the survival time of cardiac allografts in rats

Heterotopic heart transplantation was carried out in rats and the influence of multi-glycosides of Tripterygium wilfordii Hook f. (GTW) and a subtherapeutic dose of cyclosporine A (CsA) on the mean survival time (MST) of the cardiac allografts was investigated. The results showed that the MSTs of cardiac allografts in both the GTW and CsA-treated groups were significantly prolonged (P < 0.01 vs control). The rate of allograft rejection in the drug-treated groups was much lower than that in the control group.

Effect of Pluronic F-68 on the mechanical properties of mammalian cells

The mechanical properties of TB/C3 hybridoma cells taken from a continuous culture were measured by micromanipulation. The culture conditions were constant except for the presence or absence of Pluronic F-68 in the medium. It was found that the mean bursting membrane tension and the mean elastic area compressibility modulus of the cells were significantly greater (60% and 120%, respectively) in a medium with 0.05% (w/v) Pluronic F-68 compared to that without Pluronic. Pluronic F-68 therefore affected the strength of the membranes when the cells were exposed to it for a long period of time, i.e., in culture. The short-term effect of Pluronic F-68 on cell strength was also tested by its addition at various levels up to 0.2% (w/v) immediately before the mechanical property measurements. The resulting cell strength depended on the Pluronic concentration, but a significant short-term effect could only be detected above a threshold of 0.1% (w/v). Previous reports on the effect of Pluronic F-68 on animal cell culture are evaluated in the light of these observations.

Kinesin family in murine central nervous system

In neuronal axons, various kinds of membranous components are transported along microtubules bidirectionally. However, only two kinds of mechanochemical motor proteins, kinesin and brain dynein, had been identified as transporters of membranous organelles in mammalian neurons. Recently, a series of genes that encode proteins closely related to kinesin heavy chain were identified in several organisms including Schizosaccharomyces pombe, Aspergillus niddulans, Saccharomyces cerevisiae, Caenorhabditus elegans, and Drosophila. Most of these members of the kinesin family are implicated in mechanisms of mitosis or meiosis. To address the mechanism of intracellular organelle transport at a molecular level, we have cloned and characterized five different members (KIF1-5), that encode the microtubule-associated motor domain homologous to kinesin heavy chain, in murine brain tissue. Homology analysis of amino acid sequence indicated that KIF1 and KIF5 are murine counterparts of unc104 and kinesin heavy chain, respectively, while KIF2, KIF3, and KIF4 are as yet unidentified new species. Complete amino acid sequence of KIF3 revealed that KIF3 consists of NH2-terminal motor domain, central alpha-helical rod domain, and COOH-terminal globular domain. Complete amino acid sequence of KIF2 revealed that KIF2 consists of NH2-terminal globular domain, central motor domain, and COOH-terminal alpha-helical rod domain. This is the first identification of the kinesin-related protein which has its motor domain at the central part in its primary structure. Northern blot analysis revealed that KIF1, KIF3, and KIF5 are expressed almost exclusively in murine brain, whereas KIF2 and KIF4 are expressed in brain as well as in other tissues. All these members of the kinesin family are expressed in the same type of neurons, and thus each one of them may transport its specific organelle in the murine central nervous system.

Optical programmable triple-in binary logic gate

Based on the dual-rail encoding concept, beam splitting, and beam combining, an optical logic gate capable of performing all 256 logic functions of three input binary patterns is proposed. The gate is programmed by polarization customizing. The full adder and the full subtractor are thus suggested, and the experimental results are presented.

Identification of a novel retinoid-responsive element in the promoter region of the medium chain acyl-coenzyme A dehydrogenase gene

To study the mechanisms involved in regulation of nuclear genes encoding mitochondrial enzymes in oxidative energy pathways, the promoter region of the medium-chain acyl-CoA dehydrogenase (MCAD) gene was analyzed. A series of hexamer sequences known to bind and confer responsiveness to a subset of members of the nuclear receptor superfamily of transcription factors was identified. Cotransfection of an MCAD promoter-chloramphenicol acetyltransferase (CAT) reporter plasmid with retinoic acid receptor (RAR)alpha, beta, or retinoid X receptor alpha (RXR alpha) resulted in 10-15-fold transcriptional activation in response to retinoic acid. The retinoic acid-induced activation was 3-4-fold higher with RXR alpha than with either RAR alpha or RAR beta. Deletional analysis confirmed that a region between -341 and -308 base pairs upstream of the MCAD gene cap site conferred the RA-responsive transcriptional activation to homologous and heterologous promoters. Gel mobility shift assays demonstrated that the MCAD RARE interacted directly with overexpressed receptors. Mutational analysis of the RARE delineated three hexamer binding sequences with unique orientation and spacing compared to other reported retinoid responsive elements. These results indicate that the MCAD gene promoter region contains a novel regulatory element that interacts with members of the retinoid receptor family, with preferential activation by RXR alpha. This element likely plays a role in the transcriptional regulation of this gene and perhaps others involved in oxidative energy metabolism.