The carboxyl terminus of the murine MyD116 gene substitutes for the corresponding domain of the gamma(1)34.5 gene of herpes simplex virus to preclude the premature shutoff of total protein synthesis in infected human cells

The herpes simplex virus 1 mutants from which both copies of the gamma(1)34.5 gene had been deleted trigger total shutoff of protein synthesis in human neuroblastoma cells and human foreskin fibroblasts but not in African green monkey (Vero) cells. The carboxyl-terminal 64 amino acids of gamma(1)34.5 are homologous to the corresponding domain of MyD116, a murine myeloid differentiation primary responsive gene. The carboxyl-terminal domain of gamma(1)34.5 is required to preclude the shutoff of protein synthesis (J. Chou and B. Roizman, Proc. Natl. Acad. Sci. USA 91:5247-5251, 1994). We report that in-frame substitution of the carboxyl terminus of gamma(1)34.5 with the corresponding domain of MyD116 in the context of the viral genome restored the ability of gamma(1)34.5 to preclude premature shutoff of protein synthesis in both neuroblastoma cells and in human foreskin fibroblasts. The results suggest that (i) in the course of its evolution, the virus "borrowed" a gene fragment to preclude a cell response to infection and (ii) the carboxyl terminus of MyD116 and its family of genes known as GADD34 may have a similar function(s) in cells stressed by growth arrest, DNA damage, and differentiation and in herpes simplex virus infection.

Tumor necrosis factor alpha-308 alleles in multiple sclerosis and optic neuritis

Tumor necrosis factor-alpha (TNF-alpha), a proinflammatory cytokine, is believed to play an important role in multiple sclerosis (MS) pathogenesis. A bi-allelic polymorphism in the TNF-alpha promoter region (TNF alpha-308), has been reported to influence levels of TNF-alpha production. In the present study, we investigated the TNF alpha-308 polymorphism in 93 patients with MS, 17 patients with optic neuritis (ON) and 95 healthy individuals using an allele-specific PCR technique. Allelic genotype was compared with TNF-alpha mRNA expression levels and HLA class II phenotypes. No significant difference regarding the TNF alpha-308 polymorphism was observed between MS patients and controls. Specifically, the less common allele, TNF2, which is associated with higher expression levels of TNF-alpha, was somewhat less frequent among MS patients. In fact, analysis of 19 patients homozygous for the MS associated HLA-DR-DQ haplotype HLA-Dw2 showed that this haplotype does not carry the TNF2 allele. In addition, in 47 patients, the TNF-alpha alleles did not correlate with expression levels measured as numbers of TNF-alpha expressing cells. Thus, we found no evidence for an important role of TNF alpha-308 polymorphism for genetic susceptibility to MS.

Suppression of experimental autoimmune myasthenia gravis and experimental allergic encephalomyelitis by oral administration of acetylcholine receptor and myelin basic protein: double tolerance

Oral administration of acetylcholine receptor (AChR) or myelin basic protein (MBP) to Lewis rat prior to immunization with AChr or MBP and complete Freund's adjuvant (CFA) has previously been shown to prevent or delay the onset of experimental autoimmune myasthenia gravis (EAMG) or experimental allergic encephalomyelitis (EAE), which represent animal models of myasthenia gravis and multiple sclerosis, respectively. Here we show that Lewis rats immunized with AChr+MBP+CFA developed both signs of muscular weakness seen in EAMG and paresis characteristic for EAE. This disease was associated with high levels of anti-AChR and anti-MBP antibody secreting cells and of AChR- and MBP-reactive INF-gamma secreting Th1-like cells in lymph nodes. The diseased rats also showed upregulation of AChR- and MBP-induced mRNA expression of IFN-gamma in lymph node cells. Oral tolerization with AChR and MBP in combination prior to immunization with AChR+MBP+CFA alleviated clinical disease as well as AChR- and MBP-specific B cell node cells. The results implicate that oral tolerization simultaneously to more than one autoimmune disease-related autoantigen is feasible, and that suppression of autoantigen-induced IFN-gamma and augmentation of TGF-beta are pivotal in tolerance induction.

Phage RNA polymerase vectors that allow efficient gene expression in both prokaryotic and eukaryotic cells

We have developed expression vectors that direct the synthesis of proteins from a common set of signals in both prokaryotic and eukaryotic cells. To allow transcription from a common promoter the vectors rely upon a phage RNA polymerase (RNAP). To direct initiation of translation to the same start codon the vectors utilize an internal ribosome entry site (IRES) from encephalomyocarditis virus (EMCV) that has been modified to include a prokaryotic ribosome-binding site (RBS) at an appropriate distance upstream from the desired start codon. These vectors provide levels of expression in eukaryotic cells that exceed those of a conventional RNAP-II-based system by 7-fold, and expression in bacterial cells at levels comparable to other phage RNAP-based systems. Inclusion of a lac repressor and a phage promoter/lac operator fusion element allows tight regulation. Cotransfection of eukaryotic cells with the expression vector and a vector that encodes the phage RNAP provides high-level transient expression without the need to construct specialized stable cell lines.

Accumulation of 7 alpha-hydroxycholesterol in liver tissue of patients with cholesterol gallstones

Patients with cholesterol gallstones have a reduced pool of bile acids. This study was undertaken to clarify the mechanism by which bile acid biosynthesis does not increase to supranormal levels to cause a reexpansion of the pool. We investigated the first two steps of the bile acid biosynthesis pathway by assaying the activities of cholesterol 7 alpha-hydroxylase, the rate-limiting enzyme in this pathway, and 3 beta-hydroxy-delta 5-C27-steroid dehydrogenase/isomerase, and by measuring the concentrations of 7 alpha-hydroxycholesterol and 7 alpha-hydroxy-4-cholesten-3-one in liver specimens from ten patients with cholesterol gallstones and ten gallstone-free controls. In the patients with gallstones, cholesterol 7 alpha-hydroxylase activity, 3 beta-hydroxy-delta 5-C27-steroid dehydrogenase/isomerase activity, and hepatic 7 alpha-hydroxy-4-cholesten-3-one concentration did not significantly different from levels in controls, but hepatic 7 alpha-hydroxycholesterol concentration was more than twofold that of controls (12.9 +/- 2.6 vs 5.3 +/- 1.2 nmol/g liver, P < 0.01). The concentration of 7 alpha-hydroxycholesterol positively correlated with the ratio of cholesterol 7 alpha-hydroxylase activity to 3 beta-hydroxy-delta 5-C27-steroid dehydrogenase/isomerase activity (r = 0.93; P < 0.005) in the gallstone-free controls. In contrast, this correlation disappeared in the patients with gallstones. These results suggest a derangement of the normal 7 alpha-hydroxycholesterol metabolism in the patients with gallstones. The reason for the accumulation of 7 alpha-hydroxycholesterol remains unclear; however, it is possible that, in patients with cholesterol gallstone, the accumulated 7 alpha-hydroxycholesterol causes inappropriate suppression of cholesterol 7 alpha-hydroxylase activity by product inhibition.

[The effect of transforming growth factor-beta on collagen expression by human embryonic fibroblasts]

Transforming growth factor-beta (TGF-beta) is a cytokine with diverse biological activity. It can regulate the metabolic function of extracellular matrix (ECM) and play an important role in the development of pulmonary fibrosis. Collagen are major ECM components that are responsible for normal lung structure and function. Collagen accumulation is a major feature of pulmonary fibrosis. In order to study the mechanism of pulmonary fibrosis, we examined the effects of TGF-beta on the production, mRNA expression of type I collagen and type IV collagen by cultures of human embryonic lung fibroblasts. The results indicated that TGF-beta can induce collagen formation and type I collagen, type IV collagen mRNA expression without affecting cell proliferation. We concluded that TGF-beta plays a role in collagen accumulation of pulmonary fibrosis and the changes in collagen production appear to be mediated on collagen mRNA level.

Secondary structure of holo- and apo-aminoacylase from prediction, circular dichroism, and FT-Raman spectroscopy

The secondary structures of native (Holo-) and Zn(2+)-free (Apo-) aminoacylase were examined by circular dichroism (CD) and Fourier transform Raman (FT-Raman) spectroscopic techniques and prediction methods. Quantitative analysis of the conformationally sensitive amide I band indicates that Holo- and Apo-enzyme contain 19.3 and 17.2% helical structure, respectively. Far-UV CD spectra of Holo- and Apo-enzyme show that they contain 20.1 and 17.6% alpha-helix, respectively. Secondary structure prediction of aminoacylase indicates that it contains approximately 20.9% alpha-helical structure including 10 alpha-helix segments. The results show that after removal of Zn2+ in aminoacylase, the extent of ordered structure was decreased markedly. The conformation at or near the active site of aminoacylase may contain more ordered structure and the presence of Zn2+ may help to maintain the catalytically active conformation at the active site.

Inactivation and unfolding of aminoacylase during denaturation in sodium dodecyl sulfate solutions

During denaturation by sodium dodecyl sulfate (SDS), aminoacylase shows a rapid decrease in activity with increasing concentration of the detergent to reach complete inactivation at 1.0 mM SDS. The denatured minus native-enzyme difference spectrum showed two negative peaks at 287 and 295 nm. With the increase of concentration of SDS, both negative peaks increased in magnitude to reach maximal values at 5.0 mM SDS. The fluorescence emission intensity of the enzyme decreased, whereas there was no red shift of emission maximum in SDS solutions of increasing concentration. In the SDS concentration regions employed in the present study, no marked changes of secondary structure of the enzyme have been observed by following the changes in far-ultraviolet CD spectra. The inactivation of this enzyme has been followed and compared with the unfolding observed during denaturation in SDS solutions. A marked inactivation is already evident at low SDS concentration before significant conformational changes can be detected by ultraviolet absorbance and fluorescence changes. The inactivation rate constants of free enzyme and substrate-enzyme complex were determined by the kinetics method of the substrate reaction in the presence of inactivator previously described by Tsou [Tsou (1988), Adv. Enzymol. Related Areas Mol. Biol. 61, 381-436]. It was found that substrate protects against inactivation and at the same SDS concentrations, the inactivation rate of the free enzyme is much higher than the unfolding rate. The above results show that the active sites of metal enzyme containing Zn2+ are also situated in a limited and flexible region of the enzyme molecule that is more fragile to denaturants than the protein as a whole.

An equivalent body surface charge model representing three-dimensional bioelectrical activity

A new surface-source model has been developed to account for the bioelectrical potential on the body surface. A single-layer surface-charge model on the body surface has been developed to equivalently represent bioelectrical sources inside the body. The boundary conditions on the body surface are discussed in relation to the surface-charge in a half-space conductive medium. The equivalent body surface-charge is shown to be proportional to the normal component of the electric field on the body surface just outside the body. The spatial resolution of the equivalent surface-charge distribution appears intermediate between those of the body surface potential distribution and the body surface Laplacian distribution. An analytic relationship between the equivalent surface-charge and the surface Laplacian of the potential was found for a half-space conductive medium. The effects of finite spatial sampling and noise on the reconstruction of the equivalent surface-charge were evaluated by computer simulations. It was found through computer simulations that the reconstruction of the equivalent body surface-charge from the body surface Laplacian distribution is very stable against noise and finite spatial sampling. The present results suggest that the equivalent body surface-charge model may provide an additional insight to our understanding of bioelectric phenomena.

Computational flow optimization of rotary blood pump components

In an effort to improve and automate the fluid dynamic design of rotary blood pumps, a coupled computational fluid dynamics (CFD) shape optimization methodology has been developed and implemented. This program couples a finite element flow simulation with a gradient-based optimization routine to modify automatically the shape of an initial candidate blood path, according to a variety of desired fluid dynamic criteria, including shear stress, vorticity/circulation, and viscous dissipation. Preliminary results have led to both intuitive and nonintuitive transformations of the initial blood flow paths for both internal and external flows. This application of computer design optimization offers the ability to explore a much broader design space much more efficiently than would be possible with traditional parametric methods. It is believed that this computer tool can assist developers of rotary blood pumps in designing blood-wetted components that minimize thrombosis and hemolysis while simultaneously providing maximum flow performance.

Preparation of probe-modified RNA with 5-mercapto-UTP for analysis of protein-RNA interactions

We report a modified synthesis for 5-mercapto-UTP (5-SH-UTP) and its use for analysis of protein-RNA interactions utilizing Escherichia coli and T7 RNA polymerases and yeast RNA polymerases I and III. 5-SH-UTP did not affect transcriptional pausing, Rho-independent termination or recognition of the E. coli transcription complex by NusA. RNA containing 5-SH-UMP did not crosslink to polymerase when irradiation was 302 or 337 nm. Transcription complexes containing RNA substituted with 5-SH-UMP were post-transcriptionally modified to attach a photocross-linking group to thiol-tagged nucleotides in the RNA on the surface of the polymerase of free in solution. The pKa for 5-SH-UTP was determined to be 5.6, so modification of the thiol groups in the RNA with p-azidophenacyl bromide could be carried out at pH 7. Addition of the transcription termination factor Rho, a RNA binding protein, to E. coli transcription complexes resulted in RNA crosslinking to Rho and to the beta and beta' subunits of polymerase. Using 5-SH-UTP, one can distinguish RNA binding domains on the surface of RNA polymerases or other RNA binding proteins from those buried within the protein.

Cytokine mRNA profiles in mononuclear cells in acute aseptic meningoencephalitis

Cytokines are important modulators of inflammation and immune responses. Using in situ hybridization with radiolabelled cDNA oligonucleotide probes, we studied the expression of mRNA encoding the cytokines gamma interferon (IFN-gamma), interleukin 4 (IL-4), IL-6, IL-10, transforming growth factor beta (TGF-beta), tumor necrosis factor alpha (TNF-alpha), lymphotoxin, and perforin in mononuclear cells (MNC) from blood and cerebrospinal fluid (CSF) of patients with acute aseptic meningoencephalitis (AM) and from blood of healthy controls. Patients in the acute phase of AM had elevated numbers of IFN-gamma mRNA-expressing cells in the blood compared with that of controls and higher numbers of IFN-gamma mRNA-expressing cells in their CSF compared with that of convalescent-phase patients, which is in accordance with the antiviral effects of this cytokine. Upregulation of IL-4, IL-6, and IL-10 was found in convalescent-phase patients, which is consistent with the longstanding B-cell response found in AM. TGF-beta and perforin were upregulated in both stages of AM, while the numbers of blood and CSF MNC expressing cytokine mRNA of the TNF family (TNF-alpha and lymphotoxin) did not differ between patients with AM and controls. An even higher elevation in CSF was noticed for MNC expressing most of the cytokines, particularly IL-4 and TGF-beta, reflecting the autonomy of the immune response in the CSF. The definition of cytokine profiles in AM, a self-limiting and benign disease, provides a foundation for future comparisons with other infectious and inflammatory nervous system diseases.

Transforming growth factor-beta 1 suppresses autoantigen-induced expression of pro-inflammatory cytokines but not of interleukin-10 in multiple sclerosis and myasthenia gravis

Multiple sclerosis (MS) is associated with high levels of circulating T lymphocytes that respond to the myelin antigens myelin basic protein (MBP) and proteolipid protein (PLP) by producing various cytokines including interferon-gamma (IFN-gamma) that makes MS worse and transforming growth factor-beta (TGF-beta), an endogenously produced immunosuppressant that might act beneficially. To further define the role of TGF-beta in MS, we examined the effects of recombinant TGF-beta 1 (rTGF-beta 1) on autoantigen-mediated regulation of cytokines in MS and myasthenia gravis (MG). Blood mononuclear cells (MNC) were cultivated with or without rTGF-beta 1, and with or without autoantigen or the recall antigen PPD. MNC expressing cytokine mRNA were detected after in situ hybridization with radiolabeled cDNA oligonucleotide probes. Femtogram concentrations of rTGF-beta 1 suppressed MBP-, PLP- and PPD-induced upregulation of IFN-gamma, IL-4, IL-6, tumor necrosis factor-alpha (TNF-alpha), TNF-beta and perforin in MS, and acetylcholine receptor (AChR)-induced augmentation of these pro-inflammatory cytokines in MG, but had no effects on autoantigen- or PPD-induced expression of IL-10 or TGF-beta itself. rTGF-beta 1 also suppressed numbers of myelin antigen-reactive IFN-gamma- and IL-4-secreting cells in MS and AChR-reactive IFN-gamma and IL-4 secreting cells in MG. The selective suppressive effects of TGF-beta 1 on autoantigen-induced upregulation of pro-inflammatory cytokines makes TGF-beta 1 attractive as a treatment alternative in MS and MG.

[Naloxone suppresses ischemic arrhythmias via potentiating baroreflex]

AIM

To study the relationship between the anti-arrhythmia action of naloxone (Nal) and its effect on baroreflex sensitivity (BRS).

METHODS

Acute myocardial infarction was produced by ligating coronary artery in Sprague-Dawley rats. Ventricular extrasystole (VE), tachycardia (VT), and fibrillation (VF) were recorded on ECG. The slopes of linear regression (b) from systolic blood pressure and cardiac cycle after intravenous injection (i.v.) of phenylephrine 2 micrograms was taken as the BRS. The area of infarct was estimated after TTC staining.

RESULTS

Nal 0.5 mg i.v., intracisternal injection (i.c.) of Nal 0.1 mg, and i.c. beta-endorphin (beta-End) antiserum 10 microL suppressed the ischemic arrhythmias, arrhythmia score was 1.8 +/- 1.1 (Nal i.v.) vs 3.8 +/- 2.1 (Saline i.v.); 1.7 +/- 1.5 (Nal i.c.) vs 4.0 +/- 2.6 (Artificial CSF i.c.) and 1.7 +/- 1.6 (beta-End antiserum i.c.) vs 4.1 +/- 2.0 (Serum i.c.) (P < 0.05) and potentiated the BRS, BRS was 4.2 +/- 1.8 (Nal i.v.) vs 2.9 +/- 0.8 (saline i.v.); 4.5 +/- 1.7 (Nal i.c.) vs 2.8 +/- 0.7 (Artificial CSF i.c.) and 4.4 +/- 1.1 (beta-End antiserum i.c.) vs 3.0 +/- 0.9 (Serum i.c.) (P < 0.05). BRS showed negative relations to the arrhythmia scores with r of -0.69 for i.v Nal, -0.72 for i.c. Nal, and -0.67 for i.c. beta-End antiserum (P < 0.05).

CONCLUSION

Nal suppressed ischemic arrhythmias via antagonization of beta-endorphin and potentiation of BRS.

B cell responses to acetylcholine receptor in rats orally tolerized against experimental autoimmune myasthenia gravis

Oral administration of acetylcholine receptor (AChR) to Lewis rats prior to myasthenogenic immunization with AChR and complete Freund's adjuvant (CFA) results in the prevention of experimental autoimmune myasthenia gravis (EAMG), and decreased serum levels of anti-AChR antibodies. Using an ELISPOT assay, we have now determined numbers of cells in the popliteal, inguinal and mesenteric lymph nodes, spleen and thymus secreting anti-AChR IgG antibodies. Except for mesenteric lymph nodes, a marked diminution of such cells was detected in these lymphoid organs in rats orally tolerized with AChR compared to buffer-fed or vehicle-fed control rats with EAMG. Of note is that, after AChR feeding, the B cell response to AChR in thymus was diminished to the same low level as in CFA-injected, buffer-fed control rats. The relative affinity of serum anti-AChR IgG antibodies measured by KSCN-ELISA was lower in the orally tolerized rats compared to buffer-fed or vehicle-fed rats. The observations showed that oral administration of AChR, besides preventing clinical EAMG, also counteracts the development of AChR-specific B cells, especially those with high affinity antibody production, in most lymphoid organs.

Increased bile acid concentration in liver tissue with cholesterol gallstone disease

Patients with cholesterol gallstone disease have a reduced pool of bile acids. Overly sensitive feedback inhibition of bile acid synthesis has been postulated to explain this size reduction. To test this hypothesis, hepatic bile acid concentration and the activity of cholesterol 7 alpha-hydroxylase, the rate-limiting enzyme for bile acid biosynthesis, were determined in ten patients with cholesterol gallstones and ten patients without gallstones. The bile acids present in liver tissue are the sum of those returning to liver and those newly synthesized in liver. If an overly sensitive feedback inhibition truly existed in our gallstone patients, a decreased concentration of hepatic bile acids would have been expected. However, patients with cholesterol gallstones had significantly higher total (143.3 +/- 25.5 vs 64.5 +/- 10.8 nmol/g liver, P < 0.01), chenodeoxycholic (64.1 +/- 9.9 vs 29.8 +/- 5.4, P < 0.01), deoxycholic (22.8 +/- 10.9 vs 2.0 +/- 0.7, P < 0.05), and ursodeoxycholic acid (6.2 +/- 1.4 vs 1.5 +/- 0.6, P < 0.01) concentrations than patients without gallstones. The activity of cholesterol 7 alpha-hydroxylase did not differ significantly between the two groups. Impaired hepatic transport or secretion of bile acids is strongly suspected in cholesterol gallstone patients. The findings of the present study showed no evidence of overly sensitive feedback inhibition of bile acid synthesis in cholesterol gallstone patients. Bile acid pool size may be affected by the inappropriate increase of hepatic bile acids rather than by overly sensitive feedback inhibition.

Body surface Laplacian electrocardiographic mapping--a review

It is of great importance and significance to be able to noninvasively map spatially distributed cardiac electrical activity from body surface electrical recordings. The standard electrocardiographic monitoring techniques provide little spatial information regarding cardiac electrical activity. Recently, a new approach-body surface Laplacian electrocardiographic mapping-has been aggressively pursued to provide high-resolution spatial mapping of cardiac electrical activity. The fundamental innovation is the measurement of the Laplacian electrocardiogram distribution over the body surface. The body surface Laplacian electrocardiographic maps have been shown to provide enhanced ability to map multiple spatially separate cardiac bioelectric sources. This article reviews the theoretical and experimental aspects of this emerging mapping technique. First of all, the paper briefly reviews the historical development of body surface mapping and inverse solutions for mapping the distributed cardiac electrical activity. Then the paper reviews the theoretical basis of body surface Laplacian mapping and the biophysical interpretation of body surface Laplacian signals, as well as technical consideration of the Laplacian recording and instrumentation. Investigations of body surface Laplacian maps in computer models and a physical tank model, as well as physiological studies are also reviewed.

Synthesis of prostaglandin H synthase-2 by human alveolar macrophages in response to lipopolysaccharide is inhibited by decreased cell oxidant tone

We previously demonstrated that lipopolysaccharide (LPS) increases expression of the prostaglandin H synthase-2 (PGHS-2) gene (Hempel, S.L., Monick, M.M., and Hunninghake, G.W. (1994) J. Clin. Invest. 93, 391-396). In this study, the expression of the PGHS-2 gene in response to changes in cell oxidant tone was studied. During LPS exposure, inhibition of synthesis of the free radical, NO., resulted in a small decrease in prostaglandin E2 synthesis that did not reach statistical significance. There was no effect on enzyme mass or mRNA. In contrast, incubation of alveolar macrophages in the presence of LPS plus the antioxidant pyrrolidine dithiocarbamate, the spin trap 5,5-dimethyl-1-pyrroline-N-oxide, or hypoxia, resulted in near complete inhibition of prostaglandin E2 synthesis, PGHS-2 enzyme synthesis, and gene transcription of PGHS-2 mRNA. There was no evidence of cytotoxicity. These results demonstrate that synthesis of PGHS-2 in response to LPS is inhibited by agents that decrease cell oxidant tone.

[Clinical application of nasolabial subcutaneous pedicle skin flap with infraorbital artery]

The nasolabial subcutaneous pedicle skin flap with infraorbital artery has been successfully used in 5 cases when the angular artery and facial artery could not be used because of damage. The flap is a good option for small defect in nose and facial region.

Silica increases tumor necrosis factor (TNF) production, in part, by upregulating the TNF promoter

Silica causes release of tumor necrosis factor (TNF) from mononuclear phagocytes. One hypothesis is that silica increases TNF production, in part, by upregulating the TNF gene. To evaluate this hypothesis, THP-1 cells (a myelomonocytic cell line) were exposed to various amounts of silica and then the TNF gene transcription was evaluated. In this study silica caused a dose-dependent increase in TNF mRNA and the peak response occurred at 3 h following stimulation. A transient transfection assay also showed that silica upregulated expression of a TNF CAT construct in THP-1 cells. Furthermore, a nuclear run-on assay demonstrated that silica particles induce increased TNF gene transcription in exposed cells. THP-1 cells cultured for various periods of time in the presence of silica released TNF into the cell supernatants. These studies show that silica can upregulate the TNF gene, which results in the release of TNF protein from the cells.

Induction of interferon-gamma, interleukin-4, and transforming growth factor-beta in rats orally tolerized against experimental autoimmune myasthenia gravis

Oral administration of nicotinic acetylcholine receptor (AChR) to Lewis rats prior to myasthenogenic immunization with Torpedo AChR+complete Freund's adjuvant (CFA) results in the prevention of experimental autoimmune myasthenia gravis (EAMG) and the suppression of AChR-specific B cell responses and counteracts the development of AChR-reactive interferon-gamma (IFN-gamma) secreting T cells. To study the involvement of the T helper type 1 (Th1) cell-related lymphokine IFN-gamma, the Th2 cell-related interleukin-4 (IL-4), and transforming growth factor beta (TGF-beta) that suppresses the synthesis of IFN-gamma and IL-4, we used in situ hybridization with complementary DNA oligonucleotide probes to enumerate mononuclear cells (MNC) expressing mRNA for the cytokines IFN-gamma, IL-4, and TGF-beta. Upon in vivo recognition of AChR, popliteal, inguinal, and mesenteric lymph nodes, spleen and thymus of rats with EAMG contained higher levels of IFN-gamma, IL-4, and TGF-beta mRNA-expressing cells compared to CFA-injected control rats, implicating the involvement in EAMG of AChR-reactive Th1 and Th2 cells in parallel. TGF-beta was also upregulated in EAMG. Oral tolerance to EAMG was characterized by suppression of the levels of MNC expressing IFN-gamma and IL-4, but augmentation of cells expressing TGF-beta. The results suggest that IFN-gamma, IL-4, and TGF-beta are involved in the development of EAMG, and that TGF-beta is important in the induction of oral tolerance to EAMG.

Low protein diets increase neuropeptide Y gene expression in the basomedial hypothalamus of rats

Food deprivation elevates both neuropeptide Y (NPY) gene expression in the basomedial hypothalamus and NPY levels in the paraventricular nucleus (PVN). To gain a better understanding of the dietary control of NPY, we systematically examined the effects of macronutrient restriction on the gene expression of NPY in the basomedial hypothalamus and NPY content in the PVN. Rats were fed one of eight different diets for 12 d. The control group was fed a modified AIN-76 diet. One group was fed the modified AIN-76 diet but was restricted in energy by 50%. Six isocaloric (to the control diet) test diets were prepared, each with an individual macronutrient reduced by 50%. Neuropeptide Y gene expression was elevated in protein-restricted animals as well as in energy-restricted animals. Carbohydrate or fat restriction seemed to have no effect on NPY gene expression. Though the NPY content in the PVN was not different between any groups, two findings were consistent with greater NPY release in protein-restricted animals. Animals fed a low protein diet were hyperphagic and had a greater amount of body fat. This study suggests that low levels of dietary protein may have a role in the regulation of NPY gene expression.

Determination of 7 alpha-hydroxy-4-cholesten-3-one level in plasma using isotope-dilution mass spectrometry and monitoring its circadian rhythm in human as an index of bile acid biosynthesis

A highly sensitive and specific method has been developed for determination of the level of 7 alpha-hydroxy-4-cholesten-3-one in plasma. This method is based on a stable isotope-dilution technique by gas chromatography-selected-ion monitoring mass spectrometry. 7 alpha-Hydroxy-4-cholesten-3-one was extracted from plasma by saltingout extraction, and then purified by serial solid-phase extractions. The extract was treated with O-methylhydroxyl-amine hydrochloride and then dimethylethylsilylated. The resulting methyloxime-dimethylethylsilyl ether derivative was quantified by gas chromatography-selected-ion monitoring mass spectrometry with a high-resolution mode. The plasma levels of 7 alpha-hydroxy-4-cholesten-3-one were correlated with the cholesterol 7 alpha-hydroxylase activity to a higher degree than those of any other form of 7 alpha-hydroxycholesterol (r = 0.84, n = 16, p < 0.0001). The present method was applied to monitor the circadian rhythm of 7 alpha-hydroxy-4-cholesten-3-one levels in human plasma. It was concluded that the plasma level of 7 alpha-hydroxy-4-cholesten-3-one is a useful index for the monitoring of bile acid biosynthesis in the human liver.

Multiple tyrosine protein kinases in rat hippocampal neurons: isolation of Ptk-3, a receptor expressed in proliferative zones of the developing brain

Tyrosine protein kinases are likely to play an important role in the maintenance and/or development of the nervous system. In this study we have used the PCR cloning technique to isolate sequences derived from tyrosine kinase genes expressed in cultured hippocampal neurons obtained from 17.5-day-old rat embryos. Nucleotide sequence analysis of 209 independent clones revealed sequences derived from 25 tyrosine kinases, of which two corresponded to previously unreported genes. One of the PCR clones, ptk-2, belongs to the Jak family of cytoplasmic tyrosine kinases. The second clone, ptk-3, was derived from a gene encoding an additional class of tyrosine kinase receptors whose extracellular domains contain regions of homology with coagulation factors V and VIII and complement component C1. Transcripts encoding the Ptk-3 receptor are present in a variety of embryonic and adult tissues with highest levels observed in brain. During development, ptk-3 transcripts are most abundant in the proliferative neuroepithelial cells of the ventricular zone, raising the possibility that this receptor may play an important role in the generation of the mammalian nervous system.

[Repair of heel defect with a free medial plantar flap]

The results of reconstruction of plantar heel defects with a local random flap or an island medial plantar flap have in a majority of cases been satisfactory. However, in cases of extensive plantar defects, local tissue transfers are almost impossible. Since 1988, 8 cases with extensive plantar defects have been treated using free medial plantar cutaneous or musculocutaneous flaps. All flaps survived. Six weeks postoperatively, full weight-bearing was obtained and normal activities were resumed. No ulceration in the flaps has been noted in the follow up period between 6 and 24 months, and the two point discrimination was from 20 to 24 mm. The paper particularly points out the importance of nerve repair in the reconstruction, because recovery of the protective sensation is the most important factor to prevent plantar ulceration, and is the basis for good operative results.

[The effect of IL-1 receptor antagonist on bleomycin-induced pulmonary fibrosis]

Interleukin-1 (IL-1) is a cytokine with diverse biological activities. It can serve as a fibroblast (FB) growth factor which involves in the development of pulmonary fibrosis. IL-1 receptor antagonist (IL-1ra) can compete with IL-1 for occupancy of surface receptors of target cells without agonist effect. In order to find a new method to treat pulmonary fibrosis, we investigated the effect of recombinant human IL-1ra on the development of pulmonary fibrosis by evaluating collagen content, histological change, and TGF-beta mRNA expression in the rats bleomycin-induced pulmonary fibrosis. The results indicate are that there are no significant difference between the IL-1ra treated group and the control group.

[Body surface dynamic monitoring of respiratory muscles in patients with cor pulmonale]

Electromyography (EMG) of diaphragm (Edi) and intercostal muscle (Ein) in 30 healthy volunteers and 28 patients with cor pulmonale or pulmonary fibrosis were analysed. The results show that (1) there is no obvious activity of Ein to be observed and the frequency spectra are stable when the healthy volunteers breath quietly, (2) the activity of Ein and the amplitude of Edi increase when patients are in compensation stage, (3) the patients with serious respiratory failure, the amplitude of Edi decreases remarkably, (4) the frequency spectras of Edi appear wave-like changes with the breathing pattern of patients.

Regulation of Escherichia coli purA by purine repressor, one component of a dual control mechanism

Escherichia coli purA encodes adenylosuccinate synthetase, one of two enzymes required for synthesis of AMP from IMP. purA is subject to two- to threefold regulation by purR and about twofold regulation by a purR-independent mechanism. The 5'-flanking region of purA confers purR-dependent transcriptional regulation of purA but not the purR-independent regulation. Two operator sites in the 5'-flanking region which bind purine repressor in vitro and are required for in vivo regulation were identified. The purR-independent regulation may be posttranscriptional. It is now established that all transcription units involved in de novo synthesis of purine nucleotides, nine pur operons, as well as purR itself and guaBA, are subject to purR control.

[Cytosol estrogen and progesterone receptors in female genital system malignant tumors]

Specimens from 344 cases of endometrial carcinoma, 289 cases of ovarian carcinoma, 177 cases of cervical carcinoma, 10 vulva and 4 fallopian tube carcinoma were assayed for cytosol estrogen and progesterone receptor (ER, PR) contents with dextran-coated charcoal (DCC) method. Positive rates of ER and PR in these malignant tumors in relation to menstrual cycle, histological differentiation, clinical stage and prognosis of disease were studied. The results suggested that the contents of ER and PR may play a role in building endocrine therapy and prognosis in the postoperative period. Further study on vulvar and fallopian tube carcinomas should be undertaken.

Interaction of calmodulin with synthetic deletion peptides of melittin

The 26-residue peptide melittin present in bee venom has been shown to bind calmodulin tightly. In this study we synthesized the following series of deletion peptides of melittin by the solid-phase method: Mel12, Mel13, Mel14, Mel15, Mel15F. The results of this study show that the deletion peptides Mel14 and Mel15 have almost the same binding activity as the intact native peptide. Each deletion peptide forms a 1:1 complex with calmodulin according to electrophoresis analysis. When the tryptophanyl residue of Mel15 was replaced by the phenylalaninyl residue, the dissociation constant of the peptide-calmodulin complex increased. This shows the importance of the tryptophanyl residue for binding to calmodulin.

Entropic analysis of biological growth models

Using the concept of isomorphism, we provide a quantitative description of the thermodynamic characteristics of the Logistic, Bertalanffy, and Gompertz biological growth models. With the help of the entropy expressions derived from the isomorphic probabilistic models, we show that the Logistic, Bertalanffy, and Gompertz growth models have distinct thermodynamic characteristics, though they have similar sigmoid trajectories in the time domain. The entropic analysis further reveals that the Gompertz model corresponds to a completely open system, in which cells receive adequate nutrition and competition among cells can be neglected. We have also applied the present entropic analysis to the modeling of tumor growth. Our results suggest that the entropic expression provides a theoretical justification for using the Gompertz model for describing the development of tumor cell populations. The entropic analysis may play an important role in studying the mechanisms of different biological growth processes.

[Study on estrogen and progesterone receptors in endometriosis and adenomyosis]

Estrogen and progesterone receptors (ER and PR) in 18 cases of ovarian endometriosis and 13 cases of adenomyosis were determined with dextran coated charcoal (DCC) method. The levels of ER and PR in those specimens were lower than those of normal endometrium. Among the 18 cases of ovarian endometriosis, 6 (33.4%) were negative for PR, which accounted for the unsatisfactory results of progesterone treatment for some endometriosis. In the 13 cases of adenomyosis there were 10 (76.9%) showing positive PR. It is suggested that the hormone therapy may be useful to treat those young patients with adenomyosis instead of surgery. The correlation of the ER and PR levels, the treatment and prognosis in endometriosis and adenomyosis are worth further studying.

[Change of beta tubulin gene expression in the motoneurons of spinal cord during nerve regeneration]

After crushing the right sciatic nerve of rat, the contents of both tubulin and beta tubulin mRNA increased significantly in the ventral horns of spinal cord. Analysis of tubulin in bilateral ventral horns by SDS-PAGE showed that tubulin in the injured side increased by 17%-121% of the control side. The results of in situ hybridization indicated with the signals of hybridization with beta tubulin cDNA probes were 27%-70% higher in motoneurons of the ventral horns in the injury side than the control. Northern blotting analysis of tubulin mRNA in ventral horns also revealed an increase of tubulin gene expression.

Hepatic cholesterol and bile acid synthesis in Japanese patients with cholesterol gallstones

In Japan the composition of gallstones is changing rapidly from the once-predominant brown-pigment stones to cholesterol ones. The present work was undertaken to clarify the mechanism of cholesterol supersaturated bile production in Japanese patients with cholesterol gallstones. In 26 non-obese and normolipidemic patients (11 with cholesterol gallstones, 8 with black- or brown-pigment gallstones, 7 without gallstones) a liver biopsy and hepatic bile were surgically obtained under standardized conditions. The cholesterol saturation of hepatic bile was significantly higher in cholesterol gallstone patients than in gallstone-free controls (195 +/- 10 vs. 146 +/- 8%, respectively; P < 0.01). The microsomal activities of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, the rate-limiting enzyme for cholesterol synthesis, cholesterol 7 alpha-hydroxylase, the rate-limiting enzyme for bile acid synthesis, and 7 alpha-hydroxy-4-cholesten-3-one 12 alpha-hydroxylase (12 alpha-hydroxylase), the rate-limiting enzyme for cholic acid synthesis, were assayed simultaneously in the same subjects. There were positive correlations between HMG-CoA reductase and cholesterol 7 alpha-hydroxylase activities (Rs = 0.62, P < 0.005), and between cholesterol 7 alpha-hydroxylase and 12 alpha-hydroxylase activities (Rs = 0.44, P < 0.05) in all subjects, irrespective of the existence of gallstones. The activities of the three rate-limiting enzymes did not differ significantly among the three groups (cholesterol stone, pigment stone and stone-free). In conclusion, the cholesterol supersaturation of hepatic bile in nonobese and normolipidemic Japanese patients with cholesterol gallstones does not result from an increased hepatic cholesterol synthesis or a decreased bile acid synthesis.

[Analysis of estrogen receptors in normal bone and bone tumor tissues]

Thirteen human normal bone and fifteen bone tumor tissues were assayed for estrogen receptor (ER) by Dextran-coated Charcoal method (Scatchard plot). The results showed that the concentrations of ER in normal bone tissues (15.12 +/- 14.68 fmol/mg pro) were higher than that of bone malignant tumors (8.04 +/- 6.71 fmol/mg pro) P < 0.05). The binding dissociation constants (Kd) of ER in bone tumors (18.46 +/- 27.10 x 10(-11) mol/L) was lower than those in normal ones (39.91 +/- 20.13 x 10(-11) mol/L) (P < 0.025). The percentages for positive score of ER in normal and tumor ones (23.1%, 26.7%) were not significantly different (P > 0.05). Our study indicated that the variations of concentration and affinity of ER in bone related to the tumor incidence. That cytosol ER content was decreased in malignant bone tumors whereas that of affinity increase suggests an impairment or change of an intact receptor mechanism in this tissues.

Regulation of Escherichia coli glnB, prsA, and speA by the purine repressor

A strategy was devised to identify Escherichia coli genes subject to coregulation by purR. From a data base search, similarities to the pur regulon cis-acting control site were found in 26 E. coli genes. Of five genes examined in which the putative pur operator is upstream of the coding sequence, glnB, prsA, and speA bound purified purine repressor in vitro. Binding of the repressor to a pur operator in these genes was dependent upon a corepressor. The pur operator in glnB is located between two major transcription start sites that were located by primer extension mapping. The effect of purR on expression of glnB, prsA, and speA was examined by using a lacZ reporter. The results indicated two- to threefold repression of these genes by purR. Coregulation by purR provides evidence that expands the pur regulon to include glnB, prsA, and speA. These genes have functions related to nucleotide metabolism.

[Possible involvement of atrial natriuretic factor and vasopressin in antihypertensive mechanism of clonidine in humans]

To appreciate the role of some neuropeptides in the antihypertensive mechanism of clonidine, 17 patients with essential hypertension were given po clonidine 150 micrograms tid for 3 d. Plasma atrial natriuretic factor (ANF), vasopressin (Vas), and dynorphin A (Dyn A) were measured by radioimmunoassay. After the treatment, mean blood pressure (MBP), heart rate and 24 h urine norepinephrine, epinephrine were decreased, but no change was found in plasma Dyn A. The magnitudes of increased ANF and decreased Vas were correlated with the decreased MBP (r = -0.57 and 0.53, respectively, P < 0.05). These results suggest that both ANF and Vas are involved in the antihypertensive mechanism of clonidine.

Body surface Laplacian mapping of cardiac excitation in intact pigs

Relating body surface electrocardiographic signals to regional myocardial events has been a major effort in cardiac electrophysiology. Conventional electrocardiographic means do not provide sufficient spatial resolution to resolve distributed cardiac electrical activity. The purpose of this investigation was to evaluate and study the validity of a new technique--body surface Laplacian mapping--in a well-controlled experimental setting, and to test the hypothesis that the body surface Laplacian map (BSLM) can resolve normal and abnormal ventricular depolarization patterns and localize the initial site of ventricular depolarization with high spatial resolution. In this study, BSLMs were constructed from direct measurements of the surface Laplacian of the body surface potentials using an array of 64 concentric bipolar Laplacian electrodes. BSLMs were compared to body surface potential maps (BSPMs) during normal and ectopic ventricular activation in intact anesthetized pigs. The BSLM displayed highly localized images of cardiac electrical activity, indicating its ability to resolve myocardial events. The BSLM in pigs identified the pacemaking focus overlying the known location of the epicardial pacing electrode, and imaged the activation sequence associated with exogenous ventricular pacing. In contrast, in all cases the BSPM revealed a diffuse distribution of activity over the chest. The present results suggest that the BSLM provides sufficient spatial resolution to relate body surface recordings to regional myocardial events and is able to detect ventricular depolarization patterns with greater resolution than the conventional BSPM.

Simultaneous determination of mevalonate and 7 alpha-hydroxycholesterol in human plasma by gas chromatography-mass spectrometry as indices of cholesterol and bile acid biosynthesis

A very sensitive and specific method for the simultaneous determination of mevalonate and 7 alpha-hydroxycholesterol in human plasma is described. The assay is based on isotope dilution mass spectrometry: the extracts from plasma were treated with benzylamine followed by dimethylethylsilylimidazole, then the resulting dimethylethylsilyl ether derivatives of mevalonylbenzylamide and 7 alpha-hydroxycholesterol were determined by gas chromatography-mass spectrometry using high-resolution selected-ion monitoring. Simple regression analysis revealed significant correlations between the plasma level of mevalonate and the hepatic activity of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (EC 1.1.1.34) (r = 0.83, P < 0.01) and between the plasma level of free 7 alpha-hydroxycholesterol and the hepatic activity of cholesterol 7 alpha-hydroxylase (EC 1.14.13.7) (r = 0.76, P < 0.05).

Body surface Laplacian ECG mapping

A new noninvasive approach has been developed to resolve spatially distributed cardiac electrical activity by measuring the surface Laplacian of the body surface potential. Computer simulations demonstrate the ability of the Laplacian map compared with the potential map to image spatially distributed dipole sources embedded in a semi-infinite volume conductor. Body surface Laplacian mapping has been implemented in human subjects utilizing dry bipolar Laplacian electrodes and compared with potential maps obtained using the central terminal of each bipolar Laplacian electrode. The body surface Laplacian ECG distribution was found to provide better spatial resolution than the body surface potential distribution. The body surface Laplacian map appears to resolve depolarization and repolarization of different regions of the heart. Further improvements of the body surface Laplacian mapping may permit noninvasive mapping of spatially distributed intracardiac events.

Repression of Escherichia coli purB is by a transcriptional roadblock mechanism

Escherichia coli purB is regulated by a repressor-operator interaction. The purB operator is 242 bp downstream from the transcription start site and overlaps condons 62 to 67 in the protein-coding sequence (B. He, J. M. Smith, and H. Zalkin, J. Bacteriol. 174:130-136, 1992). The mechanism by which the repressor-operator interaction functions to repress transcription was investigated by a combination of promoter replacement experiments and RNA analyses. By using a trp promoter replacement that deleted 5' flanking DNA to position -986, purB expression was increased sevenfold, yet normal two- to threefold regulation was maintained. This indicates that repressor-operator control is independent of the purB promoter and other 5' flanking sequences. Transcriptional regulation was likewise independent of coupled translation. An approximately 260-nucleotide truncated in vivo purB mRNA was identified which was dependent upon repressor-operator interaction. Thus, binding of purine repressor to the purB operator inhibits transcription elongation by a roadblock mechanism. The roadblock was not influenced by a sevenfold increase in promoter strength or by an operator mutation resulting in a 2.5-fold increase in repressor-operator affinity.