Inoculation of pigs with Streptococcus suis type 2 alone or in combination with pseudorabies virus

Pigs (9 [+/- 1] weeks old) were inoculated with Streptococcus suis type 2, pseudorabies virus (PRV), or both. For each pig of groups A, B, and C the inoculum of S suis was 10(9) colony-forming units. For each pig of groups A, B, and D the inoculum of PRV was 5 x 10(3) TCID50 of either PRV strain 4892 (group A, n = 9) or PRV isolate B (group B, n = 9). The PRV strain 4892 is a highly virulent strain; isolate B causes mild clinical signs of infection in inoculated pigs. Group-C pigs (n = 9) were given S suis alone, and group-D pigs (n = 3) were inoculated only with PRV isolate B. Clinical signs of infection and development of lesions were readily seen in pigs of groups A, B, and C. Duration and severity of clinical signs of disease and lesions were reduced in pigs of group C, compared with those of the other 2 groups. Lesions, such as polyarthritis and fibrinous pericarditis, were more abundant and acute in the groups of pigs given mixed challenge exposure, compared with pigs inoculated exclusively with S suis type 2 (group C). The group of pigs inoculated with PRV isolate B alone did not manifest clinical signs of disease or lesions. Average daily gain for group-C pigs was higher, compared with that of other groups; the difference was statistically significant at P less than 0.02 and P less than 0.05 for groups B and D, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative study of 99mTc-HM-PAO SPECT brain imaging, EEG and CT scanning in epileptic patients during the interictal period

Forty patients with epilepsy in the interictal period were studied with 99mTc (HM-PAO) SPECT brain imaging, EEG and CT scanning. Four cases of generalized epilepsy had normal findings on EEG, SPECT imaging and CT scanning. Two cases of childhood benign partial seizures had abnormal EEG, but the SPECT brain imagings were normal. Regional hypoperfusions of various extents were found in 20 of the 34 patients with complex partial seizures. Among the 34 patients, 17 had abnormal EEG and 8 had abnormal CT scans. A good topographic concordance between regional HM-PAO hypofixation and EEG foci was found (39.1%). Localization of the lesion by SPECT imaging and CT scan was coincident in 5 cases (27.8%). The correlation between these three examination methods is discussed.

[The relation between the seed germination and seedling development of Bletilla striata and Mycena osmundicola etc. fungi]

This paper reports the effects of Mycena osmundicola etc. fungi on the seed germination and seedling growth of Bletilla striata. The results showed that B. striata seeds are easily germinated under normal conditions and belong to a special type among Orchidaceae. Fungi promote cotyledon differentiation and growth, as well as rhizoid formation of B. striata protocorms after seeds are sown with fungi. A liquid extract mixture enhanced the percentage of seed germination, and carbinol extract notably accelerated differentiation and growth of the protocorm's cotyledon after seeds were incubated with the liquid extract of Mycena osmundicola-culture products.

[Determination of sugar components in wild and cultured sclerotia of Grifola umbellata (pers. ex Fr.) Pilat at different ages]

Our determination indicates that in both wild and cultured sclerotia of Grifola umbellata the contents of reducing sugar decrease with the growing years; the contents of Polysaccharide peak in the second year of growth; the contents of protein increase with the growing years; the contents of fat reaches maximum in the first year of growth; in cultured sclerotia ergosterol becomes highest in contents when the plant is two years old, while in wild sclerotia it remains lowest.

Protective effect of methylprednisolone on vascular injury in rat spinal cord injury

High-dose methylprednisolone (MP) given to patients within 8 h of traumatic spinal cord improved neural function at 6 and 12 months, suggesting a probable secondary injury process that may be amenable to therapeutic intervention. Vascular injury plays an important role in the secondary injury process of CNS trauma. We have examined the effect of MP on vascular changes, including tissue edema, vascular permeability, and polymorphonuclear (PMN) cell infiltration in a rat model of spinal cord impact injury. MP significantly reduced extravasation of fluorescein isothiocyanate dextran (FITC-D), a macromolecular tracer, by 64.3% and 50.7% with trauma forces of 20 and 40 g-cm, respectively, when MP was administered IV immediately after trauma at a bolus of 165 mg/kg, with a subsequent continuous MP infusion at 31.5 mg/kg/h for 23 h. MP reduced the water content in the 40 g-cm traumatic cord lesion to 73.0% compared to the traumatic control (74.3%, p < 0.001) at the same schedule of large dose 24-h infusion. The same doses of MP showed a trend to decrease the extent of neutrophil infiltration as determined by myeloperoxidase (MPO) activity, but the change was not significant. MP had little effect in decreasing FITC-D extravasation and cord edema when given at a lower dose (bolus of 30 mg/kg with continued infusion of 1.3 mg/kg/h for 23 h). MP did not reduce extravasation of FITC-D and edema when administered IV as one bolus injection at high (165 mg/kg) or low (30 mg/kg) doses.(ABSTRACT TRUNCATED AT 250 WORDS)

Transcriptional inhibition by carcinogenic chromate: relationship to DNA damage

Hexavalent chromium compounds are carcinogenic to humans, are potent inducers of tumors in experimental animals, and can neoplastically transform cells in culture. In this study, the effects of sodium chromate on the expression of the 78-kDa glucose-regulated protein (GRP78) gene and on general transcription were investigated with respect to the DNA damage induced by this agent. DNA single-strand breaks, DNA-protein cross-links, and chromium-DNA adducts were present in CHO cells immediately after 2 h of treatment with sodium chromate. Subsequently, these types of damage were repaired at different rates. Single-strand breaks were essentially repaired after 8 h. By 24 h posttreatment, no cross-links remained in cells exposed to 30 or 150 microM chromate, although cells treated with the 300-microM concentration still contained cross-links at that time. DNA-chromium adducts remained unrepaired for at least 32 h. The moderate constitutive level of GRP78 mRNA was not affected by chromate. Chromate did, however, suppress induction of this gene by tunicamycin in a concentration-and time-dependent manner. Thirty micromolar sodium chromate (96% survival), which caused the least DNA damage, had no effect on GRP78 induction, general RNA synthesis, or mRNA synthesis. Induction of GRP78 was suppressed immediately and 12 h after treatment with 150 microM chromate (54% survival), although there was a partial recovery of induction at 24 h after treatment, which correlated with the repair of DNA-protein cross-links. In contrast, both total cytoplasmic RNA and mRNA synthesis were suppressed by approximately 60-75% for at least 32 h by 150 microM chromate. At the 300-microM concentration (8% survival), where DNA-protein cross-links persisted beyond 24 h, GRP78 induction was totally suppressed for at least 24 h, while total RNA and mRNA synthesis were suppressed by 80-90% for at least 32 h. Overall, the effects of chromate on GRP78 induction correlated most closely with the presence of DNA-protein cross-links, but suppression of total RNA and mRNA synthesis correlated with the presence of DNA-chromium adducts. These results indicate that chromate exerts differential effects on the induction of the GRP78 gene and on general transcription.

[Induced differentiation of mouse embryonic stem cells by retinoic acid and dibutyryl cyclic adenosine monophosphate]

In vitro induced differentiation of mouse embryonic stem cells (ES-5 cells), derived from 5-day 129 mouse blastocyst was studied with retinoic acid (RA) and dibutyryl cyclic adenosine monophosphate (dB-cAMP). RA only or RA with dBcAMP together can both induce monolayer ES-5 cells to differentiate into cells of two types: neuron-like cells and fibroblast-like cells. After treated with 10(-6)mol/L RA for 6 days, the differentiated cells were about 80% of all cells, among which most cells were fibroblast-like cells and others were neuron-like cells. While after 6 days of treatment with 10(-6)mol/L RA and 1 mmol/L dBcAMP, the ratio of differentiated cells can be up to 90-95%, and most cells (about 90-95% of differentiated cells) are neuron-like cells. Immunocytochemical analysis of phenotypic markers, especially GFAP and laminin, showed that the neuron-like cells were glia cells. DBcAMP affected the direction and efficiency of induction by RA. The induced differentiation by RA on attached aggregated ES-5 cells was studied as well. In this case, more cell types appeared, such as epitheloid cells, fibroblast-like cells and spindle shaped cells and so on. The exact nature of these differentiated cells was not identified. After attached culture for about 15 days, rhythmically contracting cardiac-like muscle cells were most attractive among those several differentiated cell types. The change of phenotypic markers during induced differentiation of ES-5 cells in monolayer and aggregated state was summarized in table 1. Transforming growth factor-beta 1 (TGF-beta 1) was also examined in undifferentiated and differentiated cells. Untreated ES-5 cells showed positive immunofluorescent reaction to TGF-beta 1 and various differentiated cells showed different reactions. Glia cells and cardiac-like cells displayed a much stronger TGF-beta 1 reaction. These results indicate that the exact role played by TGF-beta 1 during induced differentiation needs further investigation. The different effect of RA on monolayer and aggregated ES cells and the possible significance of cell to cell interaction in the latter case are discussed.

Structure and expression of subunit A from the bovine chromaffin cell vacuolar ATPase

Subunit A of the vacuolar H(+)-ATPase class is thought to be responsible for the ATP hydrolysis which drives proton-pumping. We report here the cloning and sequence determination of the first mammalian cDNA encoding a bovine vacuolar ATPase subunit A from an adrenal medulla cDNA library. Northern blots of bovine adrenal medulla RNA reveal a message of approximately 3.8 kb. The predicted peptide sequence, consisting of 618 amino acids with a calculated molecular weight of 68397 daltons, is similar to the sequences of the three known subunit A proteins. beta-Galactosidase-subunit A fusion proteins were immuno-decorated by an antiserum raised to the subunit A protein from corn coleoptile vacuoles.

Kininogen and kinin in experimental spinal cord injury

Activation of the kallikrein-kinin system has been implicated in the pathogenesis of vasogenic brain edema and posttraumatic vascular injury. We determined the levels of kininogen and kinin in an experimental spinal cord injury model in the rat. Kininogen content in traumatized cord segments increased in a time-dependent manner. Western blot analysis showed that the kininogen in traumatized cord comigrates with 68K low-molecular-weight kininogen or T-kininogen. Trypsin treatment of the kininogen in traumatized cord released both bradykinin and T-kinin, which were separated by HPLC and quantified with a kinin radioimmunoassay. Endogenous kinin levels in the frozen spinal cord also increased up to 40-fold 2 h after injury as compared with controls. The results demonstrate an increased accumulation of kininogen and its conversion to vasoactive kinins in experimental spinal cord injury.

[Scavenging effects of dimercaptosuccinic acid per os on nickel in mice and rats]

In mice and rats given iv or im 63NiCl2 148-370 kBq, radioactivity was present in highest concentrations in kidney, lung, and liver. After given ig dimercaptosuccinic acid (DMSA) 1 g.kg-1, radioactivity decreased remarkably in kidney, lung, and blood. The excretion of 63Ni via urine and feces within 24 h, respectively 13.0 +/- 2.4% and 0.6 +/- 0.4%, was similar to that in the control group in mice. But radioactivity increased markedly in bone. The Ni content of bone decreased on d 7. In rats given im 63NiCl2 370 kBq, two different nickel complex peaks appeared in the gel chromatograms of serum, kidney, and lung. DMSA reduced the contents of protein-bound Ni in serum, kidney, and lung. The results showed that DMSA detoxified the Ni by forming a low toxicity Ni-DMSA complex to redistribute in the body.

Evaluation of a lens opacities classification system II (LOCS II) in the survey population-based sample

In the field work of population-based research, 3 groups of eyes were graded by 2 observers in LOCS II. The reproducibility of LOCS II was evaluated by agreements (85%-100%) and k values (0.661-1) obtained in our study. The satisfying results show that LOCS II is not only easy to be learned and to be applied consistently by different observers, but also good reproducibility in the field work. The longitudinal cataract study is going to be performed in our plan.

High-performance self-pumped phase conjugator with a multichannel in KNSBN:Cu crystal

A Cu-doped (0.04 wt. %) (K(0.5)Na(0.5))(0.2)(Sr(0.61) Ba(0.39))(0.9)Nb(2)O(6) crystal produced as much as 68% self-pumped phaseconjugate reflectivity at the laser wavelength lambda = 514.5 nm. We also observed some phenomena that helped us to understand the mechanism for the self-pumped phase-conjugate mirror.

Comparison of pharmacological agents (aspartate vs. aminophosphonobutyric plus kynurenic acids) to block synaptic transmission from retinal photoreceptors in frog

The combination of aminophosphonobutyric plus kynurenic acids (APB/Kyn) was compared to aspartate with respect to its ability to block synaptic transmission from photoreceptors. Like aspartate, APB/Kyn blocks photoreceptor synaptic transmission, as monitored by the b- and d-waves of the electroretinogram, by the proximal negative response and M-wave of the proximal retina, and by the light-evoked increase in extracellular K+ concentration in the inner plexiform layer. Unlike aspartate, APB/Kyn has relatively minor effects on retinal resistance, light-evoked changes in K+ and Ca2+ concentrations in the subretinal space, light-evoked changes in subretinal space volume, resting extracellular concentrations of K+ and Ca2+ in the proximal and distal retina, and the c-wave. Effects of APB/Kyn are generally more reversible than effects of Asp. A disadvantage of APB/Kyn is that the a-wave usually becomes smaller and slower. Overall, APB/Kyn disrupts the retina less than aspartate. Therefore, in some situations in which blockade of photoreceptor synaptic transmission is desired, the use of APB/Kyn may be preferable to that of aspartate.

Molecular cloning of phosphofructokinase 1 gene from a thermophilic bacterium, Thermus thermophilus

Phosphofructokinase 1 (PFK1) from Thermus thermophilus differs from other bacterial PFKs in that it is regulated by effector-induced reversible tetramer-dimer conversion rather than conformational change alone. We have cloned its gene and the deduced amino acid sequence was compared with that of other PFKs. While almost all amino acid residues involved in substrate binding sites, which are assigned from crystal structures of other PFKs, are well conserved, some possibly important changes are found at subunit interfaces.

Inhibition of succinate-ubiquinone reductase by nitrosalicyl-N-alkylamides

The abilities of eight nitrosalicyl-N-alkylamides to inhibit succinate-ubiquinone reductase were compared. These compounds possess both a nitro group at 3- or 5-position of the benzyl ring, and a methyl, decyl, dodecyl or tetradecyl group subsituted for the amide hydrogen of salicylamide. The result shows the following: (a) 3-Nitrosalicyl-N-alkylamides are stronger inhibitors than 5-nitrosalicyl-N-alkylamides when they have the same alkyl group. (b) The inhibitory abilities of both 3-and 5-nitrosalicyl-N-alkylamides increase with increasing alkyl group length. (c) Kinetic data show that the inhibition by 3-nitrosalicyl-N-tetradecylamide is noncompetitive with respect to the electron acceptor Q2.

Brain polyphosphoinositide metabolism during focal ischemia in rat cortex

Using a rat model of stroke, we examined the effects of focal cerebral ischemia on the metabolism of polyphosphoinositides by injecting 32Pi into both the left and right cortices. After equilibration of the label for 2-3 hours, ischemia induced a significant decrease (p less than 0.001) in the concentrations of labeled phosphatidyl 4,5-bisphosphates (66-78%) and phosphatidylinositol 4-phosphate (64-67%) in the right middle cerebral artery cortex of four rats. The phospholipid labeling pattern in the left middle cerebral artery cortex, which sustained only mild ischemia and no permanent tissue damage, was not different from that of two sham-operated controls. However, when 32Pi was injected 1 hour after the ischemic insult, there was a significant decrease (p less than 0.01) in the incorporation of label into the phospholipids in both cortices of four ischemic rats compared with four sham-operated controls. Furthermore, differences in the phospholipid labeling pattern were observed in the left cortex compared with the sham-operated controls. The change in labeling pattern was attributed to the partial reduction in blood flow following ligation of the common carotid arteries. We provide a sensitive procedure for probing the effects of focal cerebral ischemia on the polyphosphoinositide signaling pathway in the brain, which may play an important role in the pathogenesis of tissue injury.

Changes in Schultz-Dale reaction in sensitized canine tracheal smooth muscle

Tracheal smooth muscles from adult dogs 17 to 20 months of age sensitized with ragweed pollen demonstrated a Schultz-Dale phenomenon in response to specific antigen challenge. Seventy percent of the sensitized tracheal smooth muscles developed a Schultz-Dale reaction that consisted only of a phasic response, and the remaining 30% developed a Schultz-Dale reaction that consisted of a phasic component followed by a discrete tonic component. All the Schultz-Dale reactions were mediated only by histamine. The triggering of presynaptic acetylcholine release by histamine during the Schultz-Dale reaction from tracheal smooth muscles of ragweed-pollen-sensitized puppies 6 to 8 months of age was not detected in sensitized adult dogs. Hyperresponsiveness to acetylcholine was detected in tissues from sensitized puppies but not from sensitized adult dogs. Maximal active tension obtained from the sensitized adult canine trachealis during the Schultz-Dale reaction was lower than that obtained from trachealis from sensitized puppies. Dose-response studies showed that sensitized tissues used in the present studies were hyperresponsive to histamine when compared with their nonsensitized control littermates. These results suggest that the nature of the Schultz-Dale response and the identity of the transmitters is age-dependent.