The relation between latissimus dorsi skeletal muscle structure and contractile function after cardiomyoplasty

Past reports suggest that structural changes within the latissimus dorsi muscle occur with chronic electrical stimulation during cardiomyoplasty. However, the specific changes in the structure of the latissimus dorsi muscle and the relation to muscle contractile function with cardiomyoplasty are unknown. Accordingly, this study examined regional changes in latissimus dorsi muscle structure and function after cardiomyoplasty. The left latissimus dorsi muscle was mobilized and wrapped around the heart in pigs with the use of standardized techniques and the latissimus dorsi muscle chronically paced at ambient heart rates (90 beats/min; 20 Hz, 5 V amplitude, n = 6). After 6 weeks, the paced latissimus dorsi muscle and the contralateral control muscle were removed and divided into proximal (0 to 3 cm), middle (3 to 6 cm), and distal (6 to 12 cm) regions. By computer-assisted morphometry, muscle cell myofibril volume, cross-sectional area, and collagen percent area were determined. In the paced latissimus dorsi muscle, myofibril volumes increased by more than 50% in the proximal and middle regions compared with those in the contralateral control muscle. However, myofibril volumes were significantly lower in the distal region of the paced latissimus dorsi muscle compared with those in control muscles (33% +/- 5% versus 20% +/- 3%, p < 0.05). In the paced latissimus dorsi muscle, cross-sectional area was significantly reduced from that of control muscles in all regions. A further reduction in cross-sectional area was noted in the distal region of the paced latissimus dorsi muscle compared with that in both the contralateral control muscle and the proximal and middle regions of the paced latissimus dorsi muscle. Collagen content significantly increased in the paced latissimus dorsi muscle compared with that in control muscle with a more fibrotic pattern observed in the distal region. Latissimus dorsi muscle strips (less than 2 mm2 cross-sectional area) were harvested, and peak and velocity of tension development were examined after field electrical stimulation at 0.2 to 1.2 Hz. At 0.2 Hz, the velocity of tension development was unchanged in the paced latissimus dorsi muscle compared with that in control muscle. However, peak tension development degraded by only 28% in the paced latissimus dorsi muscles but fell by 51% in control muscles with increased stimulation frequencies. In summary, the contractile function of the chronically stimulated latissimus dorsi muscle was associated with fatigue resistance and increased contractile protein content. However, more distal regions of the paced latissimus dorsi muscle demonstrated atrophy and fibrosis.(ABSTRACT TRUNCATED AT 400 WORDS)

Development and application of an enzyme immunoassay for karasurin A, an effective protein component of Trichosanthes kirilowii Max. var. japonicum Kitam

A method was developed for specific estimation of the content of a non-enzymatic protein, karasurin A, in fractions taken during the extraction and purification processes from a natural source. Anti-karokon serum was elicited in rabbits immunized with fragments of karokon, a dried root tuber of Trichosanthes kirilowii Max. var. japonicum Kitam. Rabbit antibody specific for karasurin A was identified in anti-karokon serum by the Western blotting method. After separation by SDS-PAGE, protein bands of purified karasurin A and extracted proteins from a medicinal herb which is a karasurin A source were reacted with anti-karokon serum followed by treatment with horseradish peroxidase (HRP)-labeled Fab' of goat anti-rabbit IgG, and then bound HRP-labeled second antibody on protein bands was developed to brown by reaction with a substrate solution of the used enzyme. A novel selected antibody enzyme immunoassay (SAEIA) for karasurin A was developed using selective binding of anti-karasurin A antibody in anti-karokon serum to solid phase karasurin A and HRP-labeled Fab' of the second antibody as the tracer. Specific estimation of the content of karasurin A in several fractions taken during the isolation and purification processes of the protein were possible using the SAEIA method.

Suppression of albumin enhancer activity by H-ras and AP-1 in hepatocyte cell lines

We demonstrated, using a transient transfection assay, that the albumin enhancer increased the expression of the albumin promoter in a highly differentiated, simian virus 40 (SV40)-immortalized hepatocyte cell line, CWSV1, but was not functional in two ras-transformed cell lines (NR3 and NR4) derived from CWSV1 by stable transfection with the T24ras oncogene. A transient cotransfection assay showed that T24ras and normal c-Ha-ras were each able to inhibit the activity of the albumin enhancer in an immortal hepatocyte cell line. DNase I footprinting and gel mobility shift assays demonstrated that the DNA binding activities specific to the albumin enhancer were not decreased in the ras-transformed cells. ras also did not diminish the expression of HNF1 alpha, C/EBP alpha, HNF3 alpha, HNF3 beta, or HNF3 gamma but did significantly increase AP-1 binding activity. Three AP-1 binding sites were identified within the albumin enhancer, and DNA binding activities specific to these AP-1 sites were induced in the ras-transformed hepatocytes. Subsequent functional assays showed that overexpression of c-jun and c-fos inhibited the activity of the albumin enhancer. Site-directed mutagenesis of the AP-1 binding sites in the albumin enhancer partially abrogated the suppressing effect of ras and c-jun/c-fos on the enhancer. These functional studies therefore supported the results of the structural studies with AP-1. We conclude that the activity of the albumin enhancer is subject to regulation by ras signaling pathways and that the effect of ras on the albumin enhancer activity may be mediated by AP-1.

Evidence that sigma factors are components of chloroplast RNA polymerase

Plastid genes are transcribed by DNA-dependent RNA polymerase(s), which have been incompletely characterized and have been examined in a limited number of species. Plastid genomes contain rpoA, rpoB, rpoC1, and rpoC2 coding for alpha, beta, beta', and beta" RNA polymerase subunits that are homologous to the alpha, beta, and beta' subunits that constitute the core moiety of RNA polymerase in bacteria. However, genes with homology to sigma subunits in bacteria have not been found in plastid genomes. An antibody directed against the principal sigma subunit of RNA polymerase from the cyanobacterium Anabaena sp. PCC 7120 was used to probe western blots of purified chloroplast RNA polymerase from maize, rice, Chlamydomonas reinhardtii, and Cyanidium caldarium. Chloroplast RNA polymerase from maize and rice contained an immunoreactive 64-kD protein. Chloroplast RNA polymerase from C. reinhardtii contained immunoreactive 100- and 82-kD proteins, and chloroplast RNA polymerase from C. caldarium contained an immunoreactive 32-kD protein. The elution profile of enzyme activity of both algal chloroplast RNA polymerases coeluted from DEAE with the respective immunoreactive proteins, indicating that they are components of the enzyme. These results provide immunological evidence for sigma-like factors in chloroplast RNA polymerase in higher plants and algae.

Inhibition of neuronal nitric oxide synthase by antipsychotic drugs

There is rapidly accumulating evidence that generation of nitric oxide (NO) through a Ca2+ and calmodulin-dependent pathway plays various important roles in the central nervous system. In the present study, effects of several antipsychotics on the activity of NO synthase were investigated in rat cerebellum and neuroblastoma N1E-115 cells, due to the known ability of these agents to inhibit calmodulin. In cytosolic preparations of rat cerebellum, the antipsychotic drugs inhibited the conversion of [3H]L-arginine into [3H]L-citrulline by NO synthase in a concentration-dependent manner. This inhibition was noncompetitive in nature, and it exhibited an excellent correlation with blockade of calmodulin activity. Furthermore, these drugs attenuated cyclic GMP formation induced by a calcium ionophore in N1E-115 cells, a response which takes place as a consequence of NO generation. Taken together, our data demonstrate that antipsychotic drugs inhibit NO formation in vitro. It is unlikely, however, that these actions might contribute to their therapeutic and/or side effects, since they take place at relatively high concentrations.

An artifact associated with using trypan blue exclusion to measure effects of amyloid beta on neuron viability

It is important to apply an appropriate test for determining cell viability, in order to properly evaluate the role of the amyloid beta protein in neuronal degeneration in Alzheimer's disease. In the current paper, we present evidence that the putative neurotoxic fragment 25-35 of amyloid beta causes loss of trypan blue exclusion in differentiated mouse neuroblastoma N1E-115 cells which suggests a potential neurotoxic effect. Surprisingly, no parallel changes in apparent cell viability were observed when fluorescein diacetate staining or release of lactate dehydrogenase were measured. Positive staining with trypan blue was also induced by incubating cell membranes prepared from N1E-115 cells or rat hippocampus with amyloid beta 25-35. Our results indicate that amyloid beta might induce trypan blue adsorption on the cell membrane. Therefore, caution should be taken when trypan blue exclusion is used in studies of the potential neurotoxicity of amyloid beta peptides.

Allosteric interaction of dynorphin and myelin basic protein with muscarinic receptors

Interaction of the basic peptides dynorphin A and myelin basic protein with muscarinic receptors was investigated in rat heart and cerebral cortex using radioligand receptor binding assays. Results showed that these peptides inhibit the binding of the muscarinic ligand [3H]N-methylscopolamine at equilibrium and alter the kinetics of ligand dissociation in an allosteric fashion. The number of basic amino acid residues in the composition of dynorphin A is important in eliciting its allosteric interactions. Our data suggest that endogenous basic peptides play a role in regulating the conformation of muscarinic receptors.

[Clinical application of the single radial immunodiffusion (SRID) technic to detect antitubercle bacillus antibody]

Using the Tubercle bacillus Danish D1331 atoxic species as antigen and by single radial immunodiffusion (SRID) technic, the serum anti-TB-Ab of 454 patients with tuberculosis or other diseases were assayed and the results were reported. It was demonstrated that the sensitivity, specificity and accuracy of this method to diagnose tuberculosis were 81.78%, 97.92% and 90.31%; the positive and negative predictivities of this method were 97.22% and 85.77%, and the diagnostic efficiency was 80.08%. It was suggested this method had significant clinical value for diagnosing of tuberculosis.

Glycosphingolipids of rabbit, sheep, and pig thymus

The thymus plays a major role in the immune system and many of the processes that occur in this tissue depend on cell-cell interactions. Glycoconjugates are known to mediate cell-cell interactions and thus to understand more fully the function of this class of compounds in thymus, structural characterization and quantification of the glycosphingolipids in thymus from sheep, rabbit, and pig were performed. Qualitative and quantitative differences were found for each species. Thymus from all three species contained neolacto (Gal beta 1-4GlcNAc) glycosphingolipids; however, significant differences in the types and quantities expressed by each animal were found. An evaluation of other classes of glycosphingolipids and their quantities demonstrate that pig thymus has a much different pattern of glycosphingolipid expression than sheep and rabbit thymus. The major glycosphingolipids in pig thymus are globo-series neutral glycosphingolipids (Gb3 and Gb4) and lactosyl-series gangliosides (GM3 and GD3). In contrast, sheep and rabbit thymus express significant levels of lacto and neolacto neutral glycosphingolipids, and also lacto and neolacto gangliosides, including three previously unidentified compounds. The major difference in glycosphingolipid expression in these two species was the presence of branched-chain gangliosides in sheep thymus.

Role of intercellular and intracellular communication by nitric oxide in coupling of muscarinic receptors to activation of guanylate cyclase in neuronal cells

Muscarinic receptor-mediated cyclic GMP formation and release of nitric oxide (NO) (or a precursor thereof) were compared in mouse neuroblastoma N1E-115 cells. [3H]Cyclic GMP was assayed in cells prelabeled with [3H]guanine. Release of NO upon the addition of muscarinic agonists to unlabeled neuroblastoma cells (NO donor cells) was quantitated indirectly by its ability to increase the [3H]cyclic GMP level in labeled cells whose muscarinic receptors were inactivated by irreversible alkylation (NO detector cells). Carbachol increased NO release in a concentration-dependent manner, with half-maximal stimulation at 173 microM (compared to 96 microM for direct activation of cyclic GMP formation). The maximal effect of carbachol in stimulating release of NO when measured indirectly was lower than that in elevating [3H]cyclic GMP directly in donor cells. Hemoglobin was more effective in blocking the actions of released NO than in attenuating direct stimulation of [3H]cyclic GMP synthesis. There was a good correlation between the ability of a series of muscarinic agonists to release NO or to activate [3H]cyclic GMP formation directly, and the potency of pirenzepine in inhibiting the two responses. Furthermore, there was a similar magnitude of desensitization of both responses by prolonged receptor activation or stimulation of protein kinase C. NO release was also regulated in relation to the cellular growth phase. A model is proposed in which a fraction of NO generated upon receptor activation does not diffuse extracellularly and stimulates cyclic GMP synthesis within the same cell where it is formed (locally acting NO). The remainder of NO that is extruded extracellularly might travel to neighboring cells (neurotransmitter NO) or might be taken back into the cells of origin (homing NO).

Solid-state NMR studies of 1H spin diffusion in adsorbed organic molecules

1H spin diffusion times of toluene (MB) and tetrahydrofuran (THF) adsorbed on a series of porous solids (charcoal, SiO2 and Al2O3) were measured by a selective inversion technique. The experimental results show that they cover a wide range (from less than one millisecond to several hundreds of milliseconds). For all samples, a tri-exponential behavior was observed in the magnetization recovery processes of the negative peaks. This is attributed to the existence of the two different kinds of spin diffusion processes in addition to the T1 relaxation. One is assigned to the intermolecular spin diffusion between the surface acidic protons of the adsorbent and the organic molecules adsorbed on the solid surface, the other to the intramolecular spin diffusion of adsorbed molecules. Due to hydrogen bonding between the surface hydroxyl groups and the adsorbate, the intermolecular spin diffusion of THF adsorbed on various solids is more effective compared to that of adsorbed MB. In addition, the intermolecular 1H spin diffusion between charcoal and adsorbed THF molecules was confirmed by indirect measurement suggested by Tekely et al.

Localization and measurement of corticostatin-I in nonpregnant and pregnant rabbit tissues during late gestation

Corticostatin-I (CSI) is the most potent of the corticostatic peptides isolated from rabbit lungs and neutrophils. CSI was localized in cells by immunohistochemistry using highly specific polyclonal antisera raised against the synthetic peptide. Western blot showed a single 4-kilodalton band, indicating that the antibody employed was specific for CSI in spleen, intestine, adrenal, and lung, but no CSI band was observed in liver. CSI was localized to macrophages in spleen, adult lung, placenta, and adult duodenum. CSI was found in epithelial cells of the upper half of the villi of the small intestine, but not in the Paneth cells. In the adrenal, CSI staining was observed only in the zona fasciculata and zona reticularis, and no immunostaining was observed in kidney, liver, heart, or ovary. CSI was measured in the maternal and fetal tissues of the pregnant rabbit on days 24, 27, and 30 of gestation and in nonpregnancy tissues. First, the peptide was extracted using mild acid conditions, purified by HPLC, and then quantitated by RIA. Immunoreactive CSI was highest in lung, spleen, intestine, and adrenal. In the brain, CSI was found in higher amounts in the pituitary, hypothalamus, and thalamus, with peak values observed at 27 days gestation. The largest amounts were found in the pituitary and hypothalamus of the nonpregnant animal. Rabbit lung had large amounts of immunoreactive CSI, with rising values in both maternal and fetal lung with progressing gestation. Again, the highest amounts were found in the lung of the nonpregnant rabbit. The adrenal contained large amounts of immunoreactive CSI, and the fetal adrenal concentrations declined with progressing pregnancy, whereas the maternal adrenal values were much lower and showed a small decline at 27 and 30 days gestation. The placenta had large amounts of immunoreactive CSI, which increased with progressing gestation. In fetal and maternal plasma, there were small amounts of ACTH, which remained constant in the maternal circulation, but increased in the fetal circulation with progressing gestation. Immunoreactive CSI was present in plasma in a much higher concentration, which decreased in the fetal compartment but increased in the maternal compartment with progressing gestation. The data presented indicate that CSI is localized to a large number of tissues in the rabbit, as visualized by immunoperoxidase staining, and that in a number of tissues it is found in macrophages. After HPLC purification from tissues, CSI was measured by RIA and found in all tissues examined except liver, kidney, heart, and ovary.(ABSTRACT TRUNCATED AT 400 WORDS)

beta-Amyloid 25-35 activates nitric oxide synthase in a neuronal clone

The role played by the beta-amyloid protein in the neuropathology which accompanies Alzheimer's disease remains unclear. In an effort to unravel some of the cellular actions of beta-amyloid, we investigated its effects on nitric oxide (NO) release in cultured neuron. The putative neurotoxic fragment 25-35 of beta-amyloid stimulated release of NO in a neuronal cell line, as measured by an increase in cyclic GMP formation which is attenuated by NO synthase inhibitors and NO scavengers. These results suggest that NO might mediate intercellular communication effected by beta-amyloid. Our results provide the first piece of evidence that beta-amyloid directly activates a putative neurotoxic second messenger transduction mechanism. These findings might be of potential value in understanding the molecular basis of Alzheimer's disease pathology and in targeting new effective therapeutic approaches.

High-resolution linkage map in the vicinity of the host resistance locus Bcg

The mouse chromosome 1 locus Bcg determines natural resistance/susceptibility of inbred mouse strains to infection with antigenically unrelated intracellular parasites, including several Mycobacterium species, Salmonella typhimurium, and Leishmania donovani. In our effort to clone Bcg, we have constructed a high-resolution genetic linkage map in the vicinity of the gene. We have developed eight new highly polymorphic markers (simple sequence repeats) corresponding to cloned genes (Vil, Inha, Des), microdissected chromosome 1 anonymous probes (lambda Mm1C136, lambda Mm1C163, lambda Mm1C165), or novel DNA markers from the region obtained by chromosome walking (D1Mcg101 and D1Mcg105). We have followed the cosegregation of these markers with respect to Bcg in a novel panel of 1000 (C57L/J x C57BL/6J) x C57BL/6J segregating backcross mice. Additional segregation analyses were carried out in preexisting panels of intra- and interspecific backcross mice and recombinant inbred strains. Three of these markers were found to be very tightly linked to Bcg: lambda Mm1C165 did not show recombination with Bcg in 1424 meioses analyzed, while D1Mcg105 and lambda Mm1C136 were located 0.1 cM proximal and 0.2 cM distal to Bcg, respectively. This analysis enabled us to define further the proximal and distal boundaries of the Bcg interval: the proximal limit was defined by a single crossover occurring between D1Mcg105 and Bcg/lambda Mm1C165/Vil, and the distal limit by 1 cross-over between Bcg/lambda Mm1C165/Vil and lambda Mm1C136 in 1683 and 575 informative meioses, respectively, for a maximal interval of 0.3 cM.(ABSTRACT TRUNCATED AT 250 WORDS)

An evaluation of the potential to use tumor-associated antigens as targets for antitumor T cell therapy using transgenic mice expressing a retroviral tumor antigen in normal lymphoid tissues

A major obstacle to the development of T cell therapy for the treatment of human tumors has been the difficulty generating T cells specifically reactive with the tumor. Most of the characterized human tumor antigens have been classified as tumor associated, because of demonstrable expression at low levels in some normal cells, and thus have not been extensively studied as potential targets of a therapeutic immune response. However, the quantitative difference in expression of such antigens between the tumor and normal cells might permit the generation of antigen-specific T cells capable of selective antitumor and not autoimmune activity. To address this issue, transgenic (TG) mice were generated that expressed low levels of Friend murine leukemia virus (FMuLV) envelope protein in lymphoid cells under the control of an immunoglobulin promoter. This protein is expressed at high levels by a Friend virus-induced erythroleukemia of C57BL/6 (B6) origin, FBL, and has been shown to serve as an efficient tumor-specific rejection antigen in B6 mice. The env-TG mice were tolerant to envelope, as reflected by the failure to detect an envelope-specific response after in vivo priming and in vitro stimulation with preparations of FMuLV envelope. However, adoptively transferred envelope-specific T cells from immunized non-TG B6 mice mediated complete eradication of FBL tumor cells in TG mice, and did not induce detectable autoimmune damage to TG lymphoid tissues. The transferred immune cells were not permanently inactivated in the TG mice, since donor T cells responded to envelope after removal from the TG mice. The lack of autoimmune injury did not reflect inadequate expression of envelope by TG lymphocytes for recognition by T cells, since TG lymphocytes functioned effectively in vitro as stimulators for envelope-specific T cells. The results suggest that this and analogous strains of TG mice may prove useful for elucidating principles for the generation and therapeutic use of tumor-reactive T cells specific for tumor-associated antigens.

An electronic cryoprobe for cryosurgery using heat pipes and thermoelectric coolers: a preliminary report

A hand-held fully electrically powered and programmable cryoprobe for general-purpose cryosurgery and cryotherapy has been developed. By combining the technologies of thermoelectric cooling and heat pipes, the temperature at the tip of the probe can easily reach -50 to -60 degrees C. It can hold below -40 degrees C when it cools a load of 10 W at the tip. Previous efforts developing cryoprobes made of thermoelectric modules have been hindered by the inherent characteristics of commercially available thermoelectric coolers: low efficiency, size and inflexible shape and very sensitive to heat intensity and thermal insulation. Matching thermoelectrics with heat pipes uses the advantages of both technologies. In the cryoprobe the heat pipe is used to focus and transport the cooling power of multi-thermoelectric modules. The heat flux for the thermoelectric modules is reduced and their efficiencies are increased. The transport of heat by a heat pipe also allows flexible access to treated spots of patients.

Nitroglycerin dinitrate metabolites do not affect the pharmacokinetics and pharmacodynamics of nitroglycerin in the dog: a preliminary report

Studies were carried out in conscious dogs to determine the effects of 1,2-glyceryl dinitrate (1,2-GDN) and 1,3-glyceryl dinitrate (1,3-GDN) on nitroglycerin (GTN) pharmacokinetics and pharmacodynamics. In the first set of experiments, steady state plasma levels (Css) of either 1,2-GDN or 1,3-GDN in three dogs were rapidly achieved by giving an iv bolus (77 micrograms/kg), followed immediately by an infusion (50 micrograms/min) of the same GDN. A single iv bolus dose of GTN (0.025 micrograms/kg) was given 50 min after beginning the GDN infusion and compared with plasma concentrations following a similar GTN dose in the absence of dosed GDNs. No significant differences in GTN AUC (p > 0.9) and CL(app) (p > 0.7) were found. In a second set of experiments, an infusion of nitroglycerin was begun in each of 4 dogs and continued for 160 min at an infusion rate of 100 micrograms/min. Steady state concentrations of GTN were achieved within 100 min, at which time the dog received, simultaneously, an iv bolus dose (5.14 mg) of one of the GDNs and an infusion dose (100 micrograms/min) of the same GDN. For both dinitrate metabolites no significant differences (p > 0.5) were found between control and interaction arterial and venous clearances, although venous GTN clearances tended to decrease in the presence of dosed GDNs. Steady state systolic blood pressure during GDN infusions could be further reduced when GTN doses were administered; however, the steady state systolic blood pressure decrease caused by GTN could not be further reduced by the GDN infusions. Results suggest that the GDNs do not inhibit nitroglycerin metabolism or hemodynamics at the dose levels studied here.

Contractile properties of isolated porcine ventricular myocytes

OBJECTIVE

The aim was to examine the structure, function, and inotropic responsiveness of isolated porcine myocytes.

METHODS

Left ventricular myocytes were harvested from six pigs with normal echocardiographic and pressure indices of left ventricular function: fractional shortening 30 (SEM 2)%, peak+dP/dt 1225(110) mm Hg.s-1, end diastolic pressure 7(2) mm Hg, and cardiac output 2.8(0.5) litres.min-1. Indices of myocyte contractility were examined using a computer assisted video edge detection system which included the percent and velocity of myocyte shortening. Myocyte contractions were recorded by alternating field stimulation at 1 Hz and measurements performed in the presence of 2-10 mM extracellular Ca2+. Contractile properties of isolated porcine myocytes were examined unattached (n = 20) or following attachment to a basement membrane substrate (n = 63).

RESULTS

Left ventricular myocytes were successfully obtained from all pigs with a 68% average yield of viable myocytes. Isolated myocyte length was 128(6) microns with an average profile surface area of 2226(51) microns 2 (coefficients of variation of 25% and 35% respectively). Electron microscopic examination showed normal cytoarchitecture with 62(4)% myofibrils by volume. Baseline extent and velocity of shortening for unattached myocytes was 6.2% and 77(10) microns.s-1 respectively. Baseline extent and velocity of shortening for myocytes adherent to a basement substrate were 4.9(0.4)% and 64(7) microns.s-1. These indices of myocyte contractile function increased from baseline values for both the unattached and attached cells with increased extracellular Ca2+.

CONCLUSIONS

Isolated porcine left ventricular myocytes retain normal cytoarchitecture and composition, respond to field stimulation, and are responsive to extracellular Ca2+. Myocytes adherent to a basement membrane substrate were capable of contracting against this resistive load.

The calmodulin antagonist calmidazolium stimulates release of nitric oxide in neuroblastoma N1E-115 cells

Effects of the calmodulin inhibitor calmidazolium on stimulation of nitric oxide (NO) release were investigated in neuroblastoma N1E-115 cells. NO release was determined indirectly by measuring cyclic GMP formation. Instead of the expected decrease in NO generation based on the calmodulin dependence of neuronal NO synthase, calmidazoline paradoxically increased cyclic GMP formation. Maximal activation occurred at 3 min and the effects were concentration dependent. This calmidazolium-stimulated NO release was markedly blocked by hemoglobin and N-monomethyl-L-arginine.

Replantation of a multiple digit and circular palm amputation: a case report

A case of successful replantation of multiple digits and circular palm amputation caused by an industrial punch force is reported. The two-level amputation was reconstructed by first replanting the severed fingers to the palmar segment and then connecting the palm segment to the hand stump. An arterial crisis was treated with urokinase, and postoperative functional recovery is described.

Mox-1 and Mox-2 define a novel homeobox gene subfamily and are differentially expressed during early mesodermal patterning in mouse embryos

We have isolated two mouse genes, Mox-1 and Mox-2 that, by sequence, genomic structure and expression pattern, define a novel homeobox gene family probably involved in mesodermal regionalization and somitic differentiation. Mox-1 is genetically linked to the keratin and Hox-2 genes of chromosome 11, while Mox-2 maps to chromosome 12. At primitive streak stages (approximately 7.0 days post coitum), Mox-1 is expressed in mesoderm lying posterior of the future primordial head and heart. It is not expressed in neural tissue, ectoderm, or endoderm. Mox-1 expression may therefore define an extensive ‘posterior’ domain of embryonic mesoderm before, or at the earliest stages of, patterning of the mesoderm and neuroectoderm by the Hox cluster genes. Between 7.5 and 9.5 days post coitum, Mox-1 is expressed in presomitic mesoderm, epithelial and differentiating somites (dermatome, myotome and sclerotome) and in lateral plate mesoderm. In the body of midgestation embryos, Mox-1 signal is restricted to loose undifferentiated mesenchyme. Mox-1 signal is also prominent over the mesenchyme of the heart cushions and truncus arteriosus, which arises from epithelial-mesenchymal transformation and over a limited number of craniofacial foci of neural crest-derived mesenchyme that are associated with muscle attachment sites. The expression profile of Mox-2 is similar to, but different from, that of Mox-1. For example, Mox-2 is apparently not expressed before somites form, is then expressed over the entire epithelial somite, but during somitic differentiation, Mox-2 signal rapidly becomes restricted to sclerotomal derivatives. The expression patterns of these genes suggest regulatory roles for Mox-1 and Mox-2 in the initial anterior-posterior regionalization of vertebrate embryonic mesoderm and, in addition, in somite specification and differentiation.

[The protective effect of Hippophae rhamnoides L. on hyperlipidemic serum cultured smooth muscle cells in vitro]

The effect of Hippophae rhamnoides on hyperlipidemic rabbit serum (HRS) cultured smooth muscle cells (SMC) was observed in comparison with vitamin E(VE). The results show that Hippophae rhamnoides, much like VE, is also a potent antioxidant. It strongly decreases the MDA content in HRS cultured SMC and protect the cells from the injury of lipid peroxidation, and thus keeps the SMC growing and proliferating health. The results implicate that Hippophae rhamnoides is an effective antioxidant, and one of the important mechanisms of Hippophae rhamnoides in anti-atherosclerosis reported recently may be closely related to the action of anti-lipid peroxidation.

Cytogenetic analysis of a uterine lipoleiomyoma

We cytogenetically analyzed a uterine lipoleiomyoma. A primary chromosomal abnormality, t(12;14), was found in all 62 cells studied. A secondary change involving chromosomes 1 and 5 was detected in 15 of 62 cells. These findings suggest that lipoleiomyomas share the same chromosomal abnormalities found in common leiomyomas. We speculate that the secondary chromosomal change involving chromosomal 5 may be responsible for the lipomatous change.

Complex allosteric modulation of cardiac muscarinic receptors by protamine: potential model for putative endogenous ligands

A large number of diverse pharmacological agents bind to a secondary domain on the muscarinic receptor, to influence allosterically the interaction of ligands at the primary binding site. Based on common structural features of these antagonists, we examined the interaction of protamine, an endogenous polycationic peptide, and of polyamines with muscarinic receptors in rat heart. Our results provide several lines of qualitative evidence that protamine allosterically modulates the conformation of muscarinic receptors, in a marked negatively cooperative manner. It decelerated the dissociation of N-[3H]methylscopolamine ([3H] NMS) initiated by atropine, in a concentration-dependent fashion. Inhibition by protamine of [3H]NMS binding at equilibrium showed a distinct plateau, which increased in magnitude at higher ligand concentrations. Scatchard analysis of saturation isotherms of [3H]NMS binding in the absence and presence of protamine indicated that protamine did not alter Bmax in a statistically significant fashion, although there was a trend of a concentration-dependent increase in this parameter. On the other hand, it caused a marked concentration-dependent decrease in the affinity of [3H]NMS, and this effect reached a ceiling limit. However, there were marked quantitative deviations of the interaction of protamine from a simple ternary allosteric model. Some of these discrepancies could be explained by the tendency of protamine to increase Bmax. The allosteric actions of protamine demonstrated in kinetic and equilibrium experiments were selective for m1 and m2 muscarinic receptors, compared with m3, m4, and m5 receptors, as studied in Chinese hamster ovary cells transfected with the genes of the different muscarinic receptors. Arginine residues play an important role in the allosteric interaction of protamine, inasmuch as poly-L-arginine qualitatively mimicked the effects of protamine. In contrast, no effects of the polyamines spermine, spermidine, and putrescine were observed on [3H]NMS binding. This is the first report on the allosteric modulation of muscarinic receptors by an endogenous peptide.

[The changes in bone mineral content in experimental limb lengthening]

The results of bone mineral content measurement in experimental limb lengthening are reported. The results demonstrated that in the restoring process, both the strength and the stiffness of the lengthened bone are positively correlated to the relative bone mineral content with coefficients of correlation 0.59 (P < 0.001) and 0.85 (P < 0.001) respectively. Analyses of curve fitting showed that the strength is directly proportional to the 1.7479 th power of bone mineral content and the stiffness to its 2.05842 th power Hence, the authors consider that bone mineral content measurement could be used as a noninvasive index for monitoring the changes of bone strength and stiffness during recovering process of bone lengthening.

Relation between ventricular and myocyte function with tachycardia-induced cardiomyopathy

Chronic supraventricular tachycardia (SVT) causes left ventricular (LV) dilatation and dysfunction. Changes in myocyte function and structure may be important factors in the development of SVT cardiomyopathy. Accordingly, LV function and isolated myocyte structure and function were examined in six pigs with pacing-induced SVT cardiomyopathy (3 weeks at 240 beats per minute) and six control pigs. LV function was examined by simultaneous echocardiography and catheterization, and isolated myocyte function was studied using computer-assisted video microscopy. Indexes of isolated myocyte contractile performance were examined in the unloaded, unattached state (31 control and 24 SVT cells) and after attachment to a basement membrane substrate (65 control and 45 SVT cells). LV fractional shortening and peak +dP/dt significantly decreased in SVT cells compared with control cells (12 +/- 2% versus 28 +/- 2%, and 842 +/- 61 versus 1,216 +/- 119 mm Hg/sec, respectively; p less than 0.05). Isolated myocyte percent shortening and normalized peak velocity of shortening of SVT myocytes adherent to a basement membrane were significantly lower than attached control myocytes (1.2 +/- 0.2% versus 4.3 +/- 0.3%, and 15 +/- 2 versus 37 +/- 5% resting cell length/sec, respectively; p less than 0.05). Similarly, in the unattached state, the extent and velocity of shortening of SVT myocytes were reduced by over 50% from control values. Contractile properties of attached and unattached cardiocytes were also examined in the presence of 2-8 mM extracellular Ca2+. For both attached and unattached SVT myocytes, responsiveness to increases in extracellular Ca2+ were significantly blunted from control values. Ultrastructural examination of SVT myocytes revealed that the percent volume of myofibrils within isolated myocytes was reduced from control values (46 +/- 7% versus 65 +/- 2%, p less than 0.05). In summary, SVT cardiomyopathy is probably due to a primary defect in isolated myocyte contractile performance. The reduced contractile function of SVT cardiomyopathic myocytes was associated with abnormalities in cytoarchitecture and Ca2+ responsiveness.

Modulation by certain conserved aspartate residues of the allosteric interaction of gallamine at the m1 muscarinic receptor

Muscarinic acetylcholine receptors belong to a superfamily of G-protein coupled receptors and contain within their structure several conserved aspartate residues. These residues have been implicated to play important roles in the interaction of agonists and their competitive antagonists with the receptor. In the present work, we investigated whether the same residues might also serve as important contact points for allosteric antagonists of muscarinic receptors, because the majority of these compounds are cationic in nature, or if such residues are involved in modification of receptor conformation by these antagonists. Gallamine was used as a prototype for these antagonists. Site-directed mutagenesis of the m1 muscarinic receptor subtype was utilized to define some of the molecular determinants involved in cooperative allosteric interactions. We report that substitution of the aspartate residue at position 71, but not at positions 99 and 122 with asparagine, affected the affinity of gallamine for the unliganded m1 receptor. A similar substitution at positions 71 and 99 decreased the magnitude of its cooperative effects on the binding of [3H]N-methylscopolamine. Our data suggest that these residues are implicated in cooperative interactions. At present, however, we cannot discount a more pivotal role of other residues on the receptor sequence in allosteric interactions. The data also support the notion that different molecular entities are required for the binding of allosteric antagonists as compared to the interaction of agonists and competitive antagonists at the receptor.

[Types of flowering branch of Magnolia denudata Desr. under high yield conditions]

The types of flowering branch of Magnolia denudata under high yield conditions were investigated. The action of axillary flowering branches on yield increase and the cultural techniques of promoting axillary flowering branch formation were evaluated. Under the same culturing conditions M. denudata var. dilutipurpurascens has hardly any axillary flowering branches.

Parallel stranded DNA under the scanning tunnelling microscope

Using scanning tunnelling microscopy, we have directly observed parallel stranded DNA helixes of 43 nucleotides in length. The double helix is right-handed and has an average spacing, 17.43 A (+/- 1 S.D.: 2.30 A), and an average apparent depth, 4.79 A (+/- 1 S.D.: 1.04 A) for each groove. The average pitch of the helical turn is 34 A (+/- 1 S.D.: 3.35 A) and consists of no more than ten base pairs. The diameter of the helix is approx. 17-20 A. Our results provide direct evidence for the existence of a parallel structure of DNA in vitro and some details of its fine structure.

Identification of broccoli and cauliflower cultivars with RAPD markers

RAPD (Random Amplified Polymorphic DNA) markers generated by 4 arbitrary 10-mer primers, discriminated 14 broccoli and 12 cauliflower cultivars (Brassica oleracea L.) by banding profiles. The size of the amplified DNA fragments ranged from 300 to 2600 base pairs. Twenty-eight percent of the markers were fixed in both broccoli and cauliflower, whereas 12.5% were specific to either crop. The rest were polymorphic in either or both crops. The markers generated by two and three primers were sufficient to distinguish each of the broccoli and cauliflower cultivars, respectively. The average difference in markers was 14.5 between broccoli and cauliflower markers, 5.8 between two broccoli cultivars and 7.9 between two cauliflower cultivars. Larger differences for each crop were found between cultivars from different seed companies than within the same company. RAPD markers provide a quick and reliable alternative to identify broccoli and cauliflower cultivars.

[Suppressive effects of safflower yellow on immune functions]

Safflower yellow (SY) extracted from Carthamus tinctorius L contained chalconoid compounds, 75% of which was safflomin A. SY ip 50-450 mg.kg-1.d-1 x 6-8 d in mice decreased serum lysozyme concentration and phagocytosing functions of both peritoneal macrophages and peripheral leukocytes; diminished the production of plaque forming cells, specific rosette forming cells, and antibody; inhibited delayed type hypersensitivity reaction and the activation of T suppressor cells elicited by supraoptimal immunization. Experiments in vitro showed inhibitory effects on [3H]TdR incorporation during human peripheral T- and B-lymphocyte proliferation by SY 0.03-3.0, 0.1-2.0 mg.ml-1 respectively, murine mixed lymphocyte culture response and the production of interleukin-2 by SY 0.1-2.5 mg.ml-1. In conclusion, SY produced declines in both nonspecific and specific immune functions.

Isolation and characterization of corticostatic peptides from guinea pig bone marrow

Three corticostatic peptides (GP-CS1, GP-CS2 and GP-CS3) were purified from extracts of guinea pig bone marrow. Each was identified on the basis of their ability to inhibit the secretion of corticosterone by isolated rat adrenal cells stimulated by ACTH. GP-CS1 and GP-CS2 were found to be 31 residues in length, rich in arginine and to have six cysteines typical of the corticostatin/defensin family of peptides previously purified from phagocytic cells of the immune system. GP-CS1 was found to be identical to GP-CS2 except for having a leucine at position 21 instead of isoleucine. GP-CS3 was also found to be rich in arginine and cysteine but structurally distinct from the other peptides. A combination of endoprotease mapping, ion-spray mass spectrometry and gas-phase sequencing revealed that GP-CS3 was a novel homo-dimer consisting of two 13 amino acid residue subunits cross-linked through eight cysteines in an anti-parellel configuration.

Subgroups of uterine leiomyomas based on cytogenetic analysis

Chromosomes from 39 cases of benign uterine leiomyomas were studied. Consistent chromosomal abnormalities were detected in 15 cases (38.5%). Abnormalities involving chromosomes 12 and 14 with or without additional chromosomal changes were found in five cases (12.8%). Deletion of chromosome 7 was detected in five cases; in three cases (7.6%), this was the only abnormality present. Complex translocations involving X, 5, and 14 as well as X, 3, and 14 were observed in one case each. Insertion of a portion of chromosome 4 to chromosome 1, deletion involving chromosome 3, and nonreciprocal translocation between chromosomes 14 and 15 were observed in one case each. Monosomy 22, with a derived chromosome 14, was observed in one case. Trisomy 7 was also identified in one case. The structural and numeric abnormalities involved chromosomes X, 1, 2, 3, 4, 5, 6, 7, 9, 10, 12, 13, 14, 15, and 22. A normal 46,XX stem line with one or two abnormal cells was observed in 20 cases. Only normal karyotypes were obtained in the remaining four cases. A review of the literature and the results of our study indicate that uterine leiomyomas may be divided into eight groups based on cytogenetic analysis.

Conformation of DNA-DNA polymerase I complex observed by scanning tunneling microscopy

The conformation of a complex of a 41 mer/31 mer DNA fragment and the Klenow fragment of DNA polymerase I of Escherichia coli was studied by scanning tunnelling microscopy (STM). The results shows that near two turns of double helix of this DNA fragment was outside of enzyme while another part containing more than one turn of helix and 10 nucleotides single strand was combined with enzyme. The dimension and shape of DNA polymerase I (KF) in complex were different from that of free enzyme. The conformation of DNA-DNA polymerase I (KF) complex and the application of STM in studying structure of complex of DNA polymerase with DNA were discussed.

Development and chromosomal localization of genome-specific markers by polymerase chain reaction in Brassica

This paper reports the application of the RAPD (random amplification of polymorphic DNA sequence) markers in Brassica genetics. Forty-seven arbitrary decamer oligonucletides were used as primers to amplify genomic DNA by polymerase chain reaction. Some of the amplified products were genome specific and could be found in both diploid and derived amphidiploid species. Of a total of 65 such markers, 16 were A genome, 37 B genome, and 12 C genome specific. Of the 37 B-genome-specific markers, 11 were mapped on four independent chromosomes of B. nigra with the aid of existing B. napus-nigra disomic alien addition lines.