Ribosomal RNA gene loci and silver-stained nucleolar organizer regions associated with heterochromatin in Alaskan char Salvelinus malma and chum salmon Oncorhynchus keta

Nucleolus-forming 5.8S, 18S and 28S ribosomal RNA gene (rDNA) loci were assigned by fluorescence in situ hybridization (FISH) to the distal half of the short arms of a large-sized submetacentric pair in the Alaskan char (Salvelinus malma) and to the distal region of the long arms of a medium-sized submetacentric pair in the chum salmon (Oncorhynchus keta), respectively. In each species, heteromorphic FISH signals, spanning whole satellite region and secondary constriction, imply an intraspecific variation in the size of rDNA loci. Size variation of silver-stained nucleolar organizer regions (AgNORs) was also apparent between or within the assigned rDNA loci in each species, suggesting a possible inter- or intralocus inactivation of rDNAs. C-band positivity of assigned rDNA loci and AgNORs unequivocally showed their association with heterochromatin in these species.

Stimulatory release of hepatic lipase activity from rat hepatocytes by ruthenium red

Ruthenium Red (RuR; ruthenium oxychloride ammoniated) stimulated the release of hepatic lipase (HTGL) activity from primary cultured rat hepatocytes into medium in a time- and dose-dependent manner. The RuR-stimulated release of HTGL activity was suppressed by tyrosine kinase (TK) inhibitors (ST-638 and biochanin A). The activity of partially purified TK preparation from hepatocytes was found to be increased by incubation with RuR. In addition, treatment of the hepatocytes with H-89, a potent inhibitor of cAMP-dependent protein kinase (PKA), decreased the stimulatory release of HTGL activity by RuR. Moreover, cAMP content in RuR-incubated hepatocytes was rapidly increased, and activation of PKA was observed. The RuR-stimulated release of HTGL activity is also inhibited by uncouplers and glycosylation inhibitors. In addition, incorporation of [3H]leucine into protein was increased in the present of RuR. Under marked inhibition of protein synthesis by cycloheximide, RuR still showed a full effect on the release of HTGL activity. These results suggest that RuR stimulates the release of HTGL activity through mechanisms of action involving TK- and PKA-activating pathways, which require a metabolic energy-sensitive process rather than elevation of enzyme molecule synthesis.

The developmental study on lamination of the optic tectum in relation to the retinotectal projection in chicks and chick embryos

The tectal lamination was investigated in the central part of the chick embryonic tectum. Two and 5 layers were observed above the neuroepithelium (NE) on embryonic day 6 (E6) and E8, respectively. Optic fibers extended on the surface of the tectum by E8. On E10-11, the outer tectum was composed of 2 layers, that is, a fibrous layer forming the optic fiber layer on the tectal surface and a cellular layer showing the gradient of cell density. In the inner tectum, the lamination was almost completed. On E12-13, the outer tectal layers, which showed the gradient of cell density, was divided into dark and light cellular layers. The dark cellular layer was divided into 2 layers on E14-15 and further into 4 layers (layer C-F in chick) on E18. On the other hand, the light cellular layer did not change until E18, but finally, it was divided into 2 layers (layer A and B in chick) by E20. Optic fibers reached the bottom of the outer tectum by E14 showing different densities of terminals. Stratification by optic fibers was going to step into the final stage on E18. On E20, laminations according to cytoarchitectural features and the optic fiber terminals were substantially completed. In the tectum affected by destruction of the contralateral embryonic eye (E4), some cellular layers were incompletely discriminated by differences of cell density.

Relationship between ATP level and respiratory rate in sea urchin embryos

In sea urchin embryos, the rate of respiration, as a result of electron transport through the mitochondrial respiratory chain, was enhanced after hatching without any change in the intrinsic capacity of electron transport in mitochondria. The increase in respiratory rate after hatching was accompanied by an evident decrease in intracellular adenosine triphosphate (ATP) concentration without any change in intracellular levels of adenosine diphosphate (ADP) and adenosine monophosphate (AMP). Adenosine triphosphate is proposed to fortify acceptor control of respiration at high concentrations and to reduce the respiratory rate even in the presence of ADP, the acceptor. The relationships between the respiratory rate and intracellular ATP concentration in embryos were the same as those in mitochondria isolated from embryos, obtained in the presence of ADP at the same concentration as in the embryos. Probably, the respiratory rate is enhanced after hatching because of the decrease in the level of ATP. In embryos kept in a medium containing adenosine, intracellular ATP concentration increased especially after hatching, without any change in the ADP level, and the respiratory rate after hatching was made as low as the rate expected, based on the relationships obtained on isolated mitochondria. The respiratory rate in embryos probably depends on intracellular ATP concentration, irrespective of the developmental stage in early development.

Substance P-immunoreactive neurons in the rostromedian area of the midbrain send axons to the lower spinal cord in the chicken

Substance P-immunoreactivity in neurons projecting to the spinal cord was examined using retrograde tract-tracing method combined with immunohistochemical techniques in chickens. Many small substance P-immunoreactive neurons were densely clustered in the midline area in the rostral midbrain, the rostromedian area (80% of the neurons in the rostromedian area). Some of these substance P-immunoreactive neurons in the rostromedian area (about 20% of substance P-immunoreactive neurons) were retrogradely labeled by small injections of wheat germ agglutinin conjugated horseradish peroxidase into the central part of the lumber segments including the intermediomedial nucleus, suggesting the projections from the rostromedian area to the lower spinal preganglionic regions. From the present data and mammalian previous studies, it was suggested that the midline area in the midbrain has fiber connections with the regions related autonomic functions, and all of which exhibit substance P-immunoreactivity.

Anti-inflammatory action of a novel peptide, SEK-1005, isolated from a Streptomyces

The pharmacological activity of a novel cyclic peptide (SEK-1005: C(45)H(70)N(8)0(13)) isolated from Streptomyces nobilis was studied in rats during the development of inflammation. SEK-1005 (0.1-0.5 mg/kg, i.p.) suppressed the passive Arthus reaction and the carrageenin-induced oedema. A steroidal anti-inflammatory drug, prednisolone (10 mg/kg, i.p.), also was effective on both inflammations. However, indomethacin (5 mg/kg, i.p.), a cyclooxygenase inhibitor, was less effective on the passive Arthus reaction. Also interesting was that the SEK-1005 effect showed its maximum level after a 24-h lag period and that its effect, as well as the prednisolone effect, was reduced by the treatment with a protein synthesis inhibitor, cycloheximide. SEK-1005 and prednisolone also showed marked protection against the adjuvant-induced arthritis, but failed to prevent the tuberculin response. These findings indicate that SEK-1005 is a new type of non-steroidal anti-inflammatory agent with an action similar to that of prednisolone.

The interspinous ligament of the lumbar spine. Magnetic resonance images and their clinical significance

STUDY DESIGN

A preliminary study of magnetic resonance features of the interspinous ligament in degenerative lumbar spine.

OBJECTIVES

To classify the magnetic resonance imaging features of the interspinous ligaments in relation to the patient's age, disc degeneration, and radiographic instability. Magnetic resonance imaging also was correlated with the histologic findings of the interspinous ligaments.

SUMMARY OF BACKGROUND DATA

As reported, rupture of the interspinous ligament frequently is found in the degenerative lumbar spine. However, little information is available in the literature on imaging assessment of the interspinous ligament in degenerative lumbar disorders.

METHODS

In this study, 24 interspinous ligaments at L1-L2 or L2-L3 from 15 patients with nondegenerated discs were selected to represent normal magnetic resonance features of the interspinous ligament, and 38 patients with the mean age of 49 years underwent functional radiography and magnetic resonance imaging. The magnetic resonance features of the interspinous ligament were classified into five categories according to their signal intensities: Type 1A (low intensity on T1- and T2-weighted images without hypertrophy of the spinal process); Type 1B (same signal pattern as in Type 1A with hypertrophy of spinal process); Type 2 (low intensity on T1- and high intensity on T2-weighted images); Type 3 (high intensity on T1-weighted images); and Type 4 (others). Seven patients with variable patterns of the interspinous ligament were selected to undergo histologic examinations.

RESULTS

Of the interspinous ligaments considered normal, 80% were classified as Type 1A. There were 14 Type 1A, 30 Type 1B, 19 Type 2, 16 Type 3, and 20 Type 4 ligaments. The mean age and disc degeneration grade of the patients with the Type 1B ligaments was significantly higher. Instability was found to be associated with Type 2 interspinous ligaments (7 of 19), whereas instability rarely was noted in Types 1A (1 of 14) and 1B (1 of 30) ligaments. The histologic examination revealed that chondrometaplasia and necrotization of fiber bundle predominated in Type 1B, proliferation of cells and vascular invasion in Type 2, fatty degeneration in Type 3 ligaments.

CONCLUSIONS

The magnetic resonance imaging characteristics may be helpful in assessing normal or pathologic changes in the interspinous ligaments.

Differentiation of Z and W chromosomes revealed by replication banding and FISH mapping of sex-chromosome-linked DNA markers in the cassowary (Aves, Ratitae)

We identified sex chromosomes of the double-wattled cassowary (Casuarius casuarius) by a replication banding method. The acrocentric Z chromosome, the fifth largest pair in males and slightly smaller W chromosome show no sign of heterochromatinization and share a nearly identical banding pattern in the distal half of the long arm. These chromosomes were further characterized by FISH with three probes linked either to Z or W chromosome in most avian species examined thus far. Contrary to the situation in the chicken, we obtained positive signals with Z-specific ZOV3 and W-specific EEO.6 in the distal region of both Z and W chromosomes. However, IREBP signals localized to the proximal half of the Z chromosome were not detected on the W chromosome. Thus, structural rearrangements such as deletions and inversions might have been the initial step of W chromosome differentiation from an ancestral homomorphic pair in this species.

The relationship between facet joint osteoarthritis and disc degeneration of the lumbar spine: an MRI study

The role of MRI in assessing facet joint osteoarthritis is unclear. By developing a grading system for severity of facet joint osteoarthritis on MRI, the relationship between disc degeneration and facet joint osteoarthritis was determined. The accuracy of MRI in assessing facet joint osteoarthritis against CT was 94%. Under 40 years of age, the degree of disc degeneration varied among individuals. Over the age of 60, most of the discs were markedly degenerated. Under 40 years of age osteoarthritic changes in facet joints were minimal. Over the age of 60, variable degrees of facet joint osteoarthritis were observed but some facets did not show osteoarthritis. No facet joint osteoarthritis was found in the absence of disc degeneration and most facet joint osteoarthritis appeared at the intervertebral levels with advanced disc degeneration. Disc degeneration is more closely associated with aging than with facet joint osteoarthritis. The present study supports the hypothesis that "disc degeneration precedes facet joint osteoarthritis", and also supports the concept that it may take 20 or more years to develop facet joint osteoarthritis following the onset of disc degeneration.

Usefulness of low-dose dobutamine stress echocardiography for evaluating reversibility of brain death-induced myocardial dysfunction

Many of the myocardial wall motion abnormalities in heart donors are reversible after transplantation, indicating that the presence of wall motion abnormalities should not automatically lead to the exclusion of donor hearts. The present study observes the natural course of brain death-induced myocardial dysfunction, and investigates whether low-dose dobutamine stress echocardiography could identify reversible myocardial dysfunction in brain-dead patients. We prospectively measured the serial changes of left ventricular fractional shortening (FS) using echocardiography and cardiac troponin T from admission to the time of cardiac standstill in 30 brain-dead patients. Patients were divided into 2 groups according to FS at the time of brain death; group I (FS > or =30%) and group II (FS <30%). Dobutamine stress echocardiography was performed in group II. Twenty-three patients were in group I and 7 patients were in group II. Four patients among 7 patients in group II showed dobutamine-nonresponsive wall motion (group IIa) and the remaining 3 patients showed dobutamine-responsive wall motion (group IIb). Troponin T at the time of brain death was markedly higher in group IIa than in groups I and IIb (5.13+/-3.79 vs 0.23+/-0.20, 0.22+/-0.16 ng/ml, p <0.0001, respectively). FS remained normal and troponin T was not increased until cardiac standstill in group I. FS remained decreased and troponin T remained elevated until cardiac standstill in group IIa, whereas FS became normal at 7 days after brain death with no change in troponin T in group IIb. Thus, some brain death-induced myocardial dysfunction is reversible and low-dose dobutamine stress echocardiography may identify reversible myocardial dysfunction.

Relationship between morphology of iliolumbar ligament and lower lumbar disc degeneration

Previous imaging studies have shown little difference in the degree of disc degeneration between L4-L5 and L5-S1. We hypothesized that because the morphology of the iliolumbar ligament affects the stability of the lumbosacral junction, then it could determine the lower lumbar disc degeneration. Fifty-three male and 47 female patients were classified into three groups according to their disc degeneration grade-those in whom the L5-S1 disc was less degenerated (group A), more degenerated (group B), and equally degenerated (group C) compared to the L4-L5 disc on T2-weighted magnetic resonance images. The length and direction of the anterior and posterior iliolumbar ligaments were measured on T1-weighted axial images. The iliolumbar ligament was shorter in group A than in group B or C, and was oriented significantly more posteriorly in group A than in groups B or C. The morphology of the iliolumbar ligament, especially its length and direction, can be a factor influencing the development of disc degeneration at L4-L5 and L5-S1.

Adsorption of Bovine Serum Albumin and Lysozyme on Hydrophobic Calcium Hydroxyapatites

The adsorption of bovine serum albumin (BSA) and lysozyme (LSZ) to oleyl phosphate(OP)-grafted calcium hydroxyapatite (OP-CaHAP) with different degrees of hydrophobicity, ranging the number of surface oleyl group per unit nm2 (nO) from 0 to 2.60, was investigated. The pronounced effects of the hydrophobic moiety of adsorbent on protein adsorption were observed. The saturated amount of adsorbed BSA (ns) was increased up to nO = 0.6 by an enlargement of hydrophobic interaction between hydrophobic CaHAP particle and proteins. However, ns decreased at nO >/= 1.3 by increasing the electrostatic repulsive force between negatively charged BSA and OP-CaHAP particles. On the other hand, the ns value of LSZ was continuously increased up to nO = 2.0 and saturated by increasing either the hydrophobic interaction or the electrostatic attraction of positively charged LSZ and negatively charged OP-grafted CaHAPs. The BSA adsorption experiment revealed that the effect of positively charged adsorption sites on the exposed ac or bc crystal faces (C-sites) of the CaHAPs is screened by the OP-groups grafted on their particle surfaces. Copyright 1999 Academic Press.

Septic arthritis of a lumbar facet joint: report of a case with early MRI findings

A 56-year-old man was hospitalized with a 2-day history of back pain and fever. A magnetic resonance (MR) scan taken on admission showed a facet joint effusion and soft-tissue abnormality posterior to the joint. Follow-up MR imaging confirmed the facet joint destruction and periarticular abscess. A biopsy specimen grew Staphylococcus aureus. MR imaging is helpful in detecting this rare infection in the earliest phase of the disease.

Chromosomal localization and heterochromatin association of ribosomal RNA gene loci and silver-stained nucleolar organizer regions in salmonid fishes

Ribosomal RNA gene (rDNA) loci, including those of nucleolus-forming 18S, 5.8S and 28S (major) and non-nucleolus-forming 5S (minor) rDNA, were assigned using fluorescence in situ hybridization (FISH) to the embryonic chromosomes of rainbow trout (Oncorhynchus mykiss), masu salmon (O. masou), brook trout (Salvelinus fontinalis) and Japanese huchen (Hucho perryi). In these species, the minor rDNA loci were located basically on 2-4 chromosome pairs, whereas the major rDNA loci were found essentially on one chromosome pair, except for the brook trout. Its major rDNA loci were dispersed on about half of the chromosome complement, showing a considerable interindividual variation in the number and location. The major and minor rDNA loci were separated onto different chromosomes in the examined species, except for the rainbow trout, in which one chromosome pair had tandemly aligned minor and major rDNA loci. Chromosome regions containing both kinds of rDNA loci in each species were found to be stained with C-banding, showing an association of these loci with heterochromatin. Comparison of the assigned major rDNA loci and sequentially detected silver (Ag)-stained nucleolar organizer regions (AgNORs) in all the species revealed a considerable polymorphism in the number and size of AgNORs among or within those loci, suggesting a possible inter- or intralocus inactivation of the major rDNAs.

Low-density lipoprotein cholesterol can be chemically measured: a new superior method

The association between elevated levels of low-density lipoprotein (LDL) cholesterol and an increased risk of premature coronary heart disease (CHD) is well documented. Most clinical laboratories estimate LDL cholesterol concentrations according to the Friedewald formula. It provides a relatively reliable estimate of LDL cholesterol concentration, provided the triglyceride concentration is <200 mg/dL. However, the reliability is considerably decreased if the triglyceride concentration is > or =400 mg/dL. The interactions between lipoproteins and surfactants, divalent cations, sugars, and lectins were investigated, and we developed a new assay protocol to chemically measure the LDL cholesterol level in serum that does not require immunoseparation or centrifugation. The assay protocol was evaluated by measuring serum samples obtained from 88 patients and 20 healthy volunteers. The triglyceride levels of the patient samples ranged from 66 to 2199 mg/dL, and the samples were classified as <200 mg/dL (n=36) and > or =400 mg/dL (n=52; 23, 3, and 26 patients had type IIb, type III, and type IV hyperlipoproteinemia, respectively) for comparative studies. The accuracy and precision of our assay protocol fulfilled the criteria of the NCEP Lipid Standardization Panel, and no matrix effect influenced the measurements. The assay protocol is less sensitive to LDL-I than to LDL-II and LDL-III. LDL cholesterol measurements correlated well with those obtained by the ultracentrifugal assay of normotriglyceridemic and hypertriglyceridemic samples. This evidence shows that the results obtained with our assay protocol are superior to those obtained with the Friedewald formula.

Antitumor-promoting naphthoquinones from Catalpa ovata

Bioassay-directed fractionation of an extract of the stem-bark of Catalpa ovata led to the isolation of three new naphthoquinones: 8-methoxydehydroiso-alpha-lapachone (1), 9-methoxy-4-oxo-alpha-lapachone (2), and (4S,4aR,10R,10aR)-4, 10-dihydroxy-2,2-dimethyl-2,3,4,4alpha,10, 10alpha-hexahydrobenzo[g]chromen-5-one (3), which is a 1,4-reductive form of 6. The known compounds 3-hydroxydehydroiso-alpha-lapachone (4), 4,9-dihydroxy-alpha-lapachone (5), 4-hydroxy-alpha-lapachone (6), and 9-methoxy-alpha-lapachone (7), and catalpalactone (8) were also isolated. Their structures were elucidated by spectral methods. These compounds all exhibited significant inhibitory activity against 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced Epstein-Barr virus early antigen (EBV-EA) activation in Raji cells.

Morphogenic activity of fibroblast growth factor-2 on primary neural precursor cells in three-dimensional culture

Mouse neural precursor cells (NPC) were dissociated from fetal heads at the 10th day of gestation. When clumps of NPC were cultured in collagen gel, they grew and reorganized neural tube-like structures in medium containing fetal calf serum at 10% and supplemented with insulin, transferrin, cholera toxin and selenite. However, dissociated NPC died when they were cultured in collagen gel at low density in the same medium. Addition of fibroblast growth factor-2 (FGF-2) to this culture stimulated growth of NPC and formation of neural tube-like structures. The requirement for FGF-2 disappeared in high seeding density culture: they grew and formed neural tube-like structures without FGF-2. The structures formed in collagen gel were immunohistochemically positive against anti-FGF-2 antibody. The results show that the three-dimensional culture system provides a useful tool to study the roles of FGF-2 in morphogenesis of the central nervous system.

Probable participation of phospholipase A2 reaction in the process of fertilization-induced activation of sea urchin eggs

In sea urchin eggs activated by sperm, A23187 or melittin, BPB (4-bromophenacyl bromide, a phospholipase A2 inhibitor) blocked fertilization envelope formation and transient CN(-)-insensitive respiration in a concentration-dependent manner. BPB had virtually no effect on the increase in [Ca2+]i (cytosolic Ca2+ level), the activity of phosphorylase a and the rate of protein synthesis, as well as acid production and augmentation of CN(-)-sensitive respiration. BPB also inhibited fertilization envelope formation and augmentation of CN(-)-insensitive respiration induced by melittin. Melittin, known to be an activator of phospholipase A2, induced the envelope formation, acid production, augmentation of CN(-)-insensitive and sensitive respiration, but did not cause any increase in [Ca2+]i, the phosphorylase a activity and the rate of protein synthesis. An activation of phospholipase A2 induced by Ca2+ or melittin seems to result in cortical vesicle discharge and production of fatty acids, which are to be utilized in CN(-)-insensitive lipid peroxidase reactions. Activation of other examined cell functions in eggs activated by sperm or A23187, probably results from Ca(2+)-triggered sequential reactions other than Ca(2+)-caused activation of phospholipase A2.

Uniparental chromosome elimination in the early embryogenesis of the inviable salmonid hybrids between masu salmon female and rainbow trout male

Chromosome elimination through chromosome loss and partial deletion is known to be one of the causes of embryonic inviability in some salmonid interspecific hybrids. Using fluorescence in situ hybridization and related techniques, including whole chromosome painting and comparative genomic hybridization, parental origin of eliminated chromosomes was identified in the inviable hybrids between masu salmon (Ms, Oncorhynchus masou) female and rainbow trout (Rb, O. mykiss) male at the early embryonic stage prior to death. In these hybrids, the haploid Rb chromosome number decreased to nearly half, whereas the Ms chromosomes were retained as one or occasionally two full haploid complements. The Rb chromosomes were also involved in the frequently observed fragments and micronuclei. Whereas the occurrence of fragments was constant throughout the observed period, chromosome loss occurred mainly from just after fertilization to the blastulae stage. In tissue sections and cell spreads of late blastula, some Rb chromosomes were trapped in the midzone from ana- to telophase, resulting in micronuclei at the subsequent interphase. Micronuclei and mitotic abnormalities were also observed in the androgenetic haploid hybrids. However, such abnormalities were seldom or never observed in the viable reciprocal hybrids. The present findings suggest that the paternal Rb chromosomes in the inviable hybrids are preferentially eliminated through mitotic abnormalities during early embryogenesis, owing to a possible incompatibility between the maternal Ms cytoplasm and paternal Rb genome.

Does the respiratory rate in sea urchin embryos increase during early development without proliferation of mitochondria?

During early development of the sea urchin, the respiratory rate, enhanced upon fertilization, is maintained up to hatching (pre-hatching period) and then gradually increases to a maximum at the gastrula stage (post-gastrula period). Except for a short duration after fertilization, respiration in embryos is strongly inhibited by CN- and antimycin A. During the whole span of early development, the amounts of proteins, cytochromes and the specific activities of cytochrome c oxidase and reduced nicotinamide adenine dinucleotide (NADH) cytochrome c reductase in mitochondria are practically the same as in unfertilized eggs. A marked augmentation of mitochondrial respiration after hatching probably occurs without net increase in whole mitochondrial intrinsic capacities. Carbonylcyanide p-trifluoromethoxyphenylhydrazone (FCCP) or tetramethyl p-phenylenediamine (TMPD) enhances the respiratory rate in the pre-hatching period but hardly augments the respiration in the post-gastrula period. In the presence of both FCCP and TMPD, the respiratory rate in the pre-hatching period was as high as in the post-gastrula period. Probably, electron transport in the mitochondrial respiratory chain is regulated by acceptor control and limitation of cytochrome c reduction in the pre-hatching period and released from those regulations in the post-gastrula period. Acceptor control of respiration is experimentally reproduced in isolated mitochondria by making adenine nucleotide levels as those levels in the pre-hatching period.