Platelet activating factor-induced microvascular permeability increases in the cat hindlimb

Changes in microvascular permeability induced by platelet activating factor (PAF) were measured in the isolated, perfused cat hindlimb preparation, and compared to the effect produced by another inflammatory mediator, histamine. Permeability was assessed from changes in the protein reflection coefficient, as measured from changes in hematocrit and protein concentration resulting from microvascular fluid filtration. The findings were 1) PAF produces transient increases in permeability similar to histamine, but PAF is approximately 30 times as potent; 2) the permeability changes induced by 76 nM PAF can be totally inhibited by the specific PAF receptor blocker WEB-2086, but the blocker can only partially inhibit 380 nM PAF, a dose that produces a maximal increase in permeability; 3) Diphenhydramine (2 microM), an H1-receptor blocker, totally inhibits the transient permeability increase produced by 2 microM histamine; 4) Cimetidine (2 or 20 microM), an H2 blocker, could not inhibit this latter increase; 5) Isoproterenol (1 microM), a beta-agonist, totally inhibited the permeability increase produced by 1 microM histamine, but 10 microM isoproterenol only partially inhibited the maximal permeability increase produced by 10 microM histamine; 6) Isoproterenol could not inhibit PAF's permeability effect; and 7) PAF's effects were unchanged by depletion of white blood cells in the perfusate. These results suggest that PAF and histamine work through different pathways to increase permeability, but the final step of endothelial contraction, which opens large inter-endothelial gaps, occurs in response to both mediators. In addition, when concentrations of these inflammatory agents are sufficient to produce maximal permeability increases, as can occur in shock situations, then the permeability increases are more sustained and resistant to receptor inhibition.

Three adjacent genes of African swine fever virus with similarity to essential poxvirus genes

Nucleotide sequencing of the right end of the SalIj fragment of the highly virulent Malawi Lil20/1 strain of African swine fever virus (ASFV) has revealed three adjacent genes with similarity to: serine-threonine protein kinases; members of the putative helicase superfamily SF2; and the vaccinia virus 56 kDa abortive late protein. All three genes are transcribed to the left with respect to the orientation of the ASFV genome. Gene L19IL predicts a protein similar to serine-threonine protein kinases including vaccinia virus gene B1R. Gene L19KL predicts a protein that is likely to be a nucleic acid-dependent ATPase, as it has similarity to both the poxvirus 70 kDa early transcription factor subunit and the poxvirus nucleoside triphosphatase I gene. Gene L19LL has extensive similarity to the vaccinia virus 56 kDa abortive late protein.

Phase I trial of low-dose, prolonged continuous infusion fluorouracil plus interferon-alfa: evidence for enhanced fluorouracil toxicity without pharmacokinetic perturbation

PURPOSE

To determine the maximum-tolerable dose (MTD) of fluorouracil (5-FU) administered as a low-dose, prolonged continuous intravenous infusion (PCI) plus interferon-alfa (IFN-alpha) that would permit treatment for at least 28 consecutive days, and to determine the effect of IFN-alpha on 5-FU pharmacokinetics.

PATIENTS AND METHODS

Twenty-six assessable patients with advanced cancer received low-dose PCI 5-FU (150, 200, 250, and 300 mg/m2/d) plus IFN-alpha, 5 x 10(6) IU/m2 administered subcutaneously (SC) at hour 48 of the 5-FU infusion, then thrice weekly thereafter in cohorts of at least three patients. Treatment continued until treatment-limiting toxicity (TLT) developed, such as mucositis, diarrhea, or fatigue. Escalation to the next 5-FU dose level occurred if none of three or zero to two of six patients developed TLT before day 28. Quantitation of plasma 5-FU concentration by high-performance liquid chromatography was performed in 15 patients. Data were standardized using the Cosinor method and compared before and after IFN-alpha administration using the paired t test.

RESULTS

The mean number of days of continuous 5-FU therapy for patients receiving 150, 200, 250, and 300 mg/m2/d of 5-FU plus IFN alfa-2a (IFN-alpha 2a) was 75, 54, 37, and 22 days, respectively. The MTD of PCI 5-FU by our criteria that could be combined with IFN-alpha was 250 mg/m2/d. Comparison of the standardized pharmacokinetic data showed no significant effect of IFN-alpha on plasma 5-FU concentration, and no alteration of the normal circadian variation in plasma 5-FU concentration that was evident before IFN-alpha administration. Objective response occurred in patients with adenocarcinoma of the pancreas (n = 3), kidney (n = 2), and lung (n = 1).

CONCLUSION

IFN-alpha substantially enhanced the gastrointestinal toxicity of low-dose PCI 5-FU without affecting 5-FU pharmacokinetics, contrary to previous reports using alternative 5-FU schedules in which IFN-alpha-related enhancement of 5-FU toxicity was attributable to reduced 5-FU clearance. Our findings suggest that under certain conditions, mechanisms other than altered 5-FU pharmacokinetics may be responsible for the ability of IFN-alpha to enhance the toxic effects of 5-FU.

Acoustic response properties of single units in the torus semicircularis of the goldfish, Carassius auratus

Single units of the goldfish torus semicircularis (TS) were recorded in response to pure tones. Response areas (RA) were obtained by recording the number of spikes evoked by tones in a range of frequencies and levels within the units' dynamic range. RAs gave estimates of best sensitivity (BS), characteristic frequency (CF), most excitatory frequency at each level (BF), and Q10dB. Peri-stimulus-time histograms (PSTH), interspike interval histograms (ISIH), and period histograms were obtained at various frequencies and levels to describe the units' temporal response patterns. The distribution of CF is nonuniform with modes at 155, 455, and 855 Hz. The distribution of the coefficient of synchronization to standard tones is also nonuniform, revealing a dichotomy between units with little or no phase-locking and those that phase-lock strongly. PSTHs for units without significant phase-locking vary widely and include patterns resembling those of the mammalian auditory brainstem. Compared with saccular afferents, torus units tend to have lower spontaneous rates, greater sensitivity, and sharper tuning. Unlike saccular afferents, BF is independent of level for most torus units. Some torus units are similar to saccular afferents while others reveal significant transformations of information between the periphery and the midbrain.

An African swine fever virus gene with similarity to the proto-oncogene bcl-2 and the Epstein-Barr virus gene BHRF1

An open reading frame, LMW5-HL, in the African swine fever virus genome displays a high degree of similarity to the proto-oncogene bcl-2 and, to a lesser degree, the Epstein-Barr virus gene BHRF1. A highly conserved central region is found in all three proteins. LMW5-HL encodes a protein of 18 kDa that is present in infected porcine macrophages at both early and late times postinfection. The similarity of LMW5-HL to bcl-2 and BHRF1 suggests a role for it in cell maintenance during productive or persistent viral infection.

Relationship between circadian-dependent toxicity of 5-fluorodeoxyuridine and circadian rhythms of pyrimidine enzymes: possible relevance to fluoropyrimidine chemotherapy

Previous studies in experimental animals and patients have suggested a circadian variation in host toxicity following administration of 5-fluorodeoxyuridine (FdUrd) although the biochemical mechanisms are not fully understood. Thymidine kinase (TK; EC 2.7.1.21), the initial enzyme in the thymidine-phosphorylation pathway, is the first enzyme in the anabolism of FdUrd. Dihydropyrimidine dehydrogenase (DPD; EC 1.3.1.2), is the rate-limiting enzyme in the pyrimidine catabolic pathway and has been shown to be the key enzyme in FdUrd catabolism. The present study examined the relationship between the suggested circadian variation in FdUrd toxicity and potential circadian variations in the activity of these enzymes. Initial studies in Sprague-Dawley rats confirmed that the time of FdUrd administration affected death rate and other drug-related toxicities including loss of body weight, diarrhea, and bone marrow suppression, with the least toxicity and highest survival rate being observed in rats receiving FdUrd at 12:00 noon and 4:00 p.m. and the greatest toxicity and lowest survival rate at 12:00 midnight and 4:00 a.m. Statistical analysis revealed a circadian pattern in FdUrd toxicity (Cosinor analysis, P < 0.001). In subsequent studies with the same species, we simultaneously measured TK and DPD activities in several tissues at various times over 24 h. Under standardized light conditions (lights on, 6:00 a.m. to 6:00 p.m.; lights off, 6:00 p.m. to 6:00 a.m.), with sampling at 4-h intervals (4:00 and 8:00 a.m.; 12:00 noon; 4:00 and 8:00 p.m., and 12:00 midnight), a circadian variation in TK activity was observed (P < 0.0001, Cosinor analysis) in bone marrow, intestinal mucosa, liver, and spleen. In the same group of animals, a circadian pattern of DPD activity in liver and bone marrow was also observed (Cosinor analysis, P < 0.0001) that was inverse compared to the circadian variation in TK activity (Pearson correlation analysis, P < 0.05). Further statistical analysis indicated that the observed circadian variation in FdUrd toxicity was correlated with the circadian variation of TK activity and inversely correlated with DPD activity (Pearson correlation analysis, P < 0.05). Based on the above data, we conclude that the circadian pattern of TK and DPD activity may explain the observed circadian variation in toxicity as the time of FdUrd administration is varied. These results may be useful in the design of improved chemotherapeutic regimens using time-modified administration of FdUrd.

Hemodynamic effects of terazosin in congestive heart failure

To determine the hemodynamic effects of a new alpha-1 blocker, terazosin, in congestive heart failure, 10 patients with this condition underwent hemodynamic testing at rest. Thirty minutes after the oral administration of 4 mg terazosin, mean right atrial pressure, mean pulmonary artery pressure and pulmonary capillary wedge pressure were found to be decreased, while the cardiac index was increased significantly. Improvement in hemodynamics persisted for more than 15 h, without an increase in heart rate. It is suggested that terazosin may have effective applications in the treatment of congestive heart failure.

[Effects of interfacial state and bonding on the biostrength of plat castable ceramics crown]

Plat castable ceramics (PCC) restorations depend primarily on their biostrength. In our experiment the human oral physiological environment was simulated and we studied the effects of restoration-tooth interfacial state and bonding on the biostrength of PCC crowns. The bond strength affects the biostrength of PCC crowns obviously. The interfacial treatment affects not only the bond strength between PCC crown and tooth structure but also the biostrength of the crown cemented.

Tension transients initiated by photogeneration of MgADP in skinned skeletal muscle fibers

Addition of MgADP to skinned skeletal muscle fibers causes a rise in Ca(2+)-activated isometric tension. Mechanisms underlying this tension increase have been investigated by rapid photogeneration of ADP within skinned single fibers of rabbit psoas muscle. Photolysis of caged ADP (P2-1(2-nitrophenyl)ethyladenosine 5'-diphosphate) resulted in an exponential increase in isometric tension with an apparent rate constant, kADP, of 9.6 +/- 0.3 s-1 (mean +/- SE, n = 28) and an amplitude, PADP, of 4.9 +/- 0.3% Po under standard conditions (0.5 mM photoreleased MgADP, 4 mM MgATP, pH 7.0, pCa 4.5, 0.18 M ionic strength, 15 degrees C). PADP depended upon the concentration of photoreleased MgADP as well as the concentration of MgATP. A plot of 1/PADP vs. 1/[MgADP] at three MgATP concentrations was consistent with competition between MgADP and MgATP for the same site on the crossbridge. The rate of the transient, kADP, also depended upon the concentration of MgADP and MgATP. At both 4 and 1 mM MgATP, kADP was not significantly different after photorelease of 0.1-0.5 mM MgADP, but was reduced by 28-40% when 3.5 mM MgADP was added before photorelease of 0.5 mM MgADP. kADP was accelerated by about twofold when MgATP was varied from 0.5 to 8 mM MgATP. These effects of MgATP and MgADP were not readily accounted for by population of high force-producing states resulting from reversal of the ADP dissociation process. Rather, the results suggest that competition between MgADP and MgATP for crossbridges at the end of the cycle slows detachment leading to accumulation of force-generating crossbridges. Elevation of steady-state Pi concentration from 0.5 to 30 mM caused acceleration of kADP from 10.2 +/- 0.5 to 27.8 +/- 1.8 s-1, indicating that the tension rise involved crossbridge flux through the Pi dissociation step of the cycle.

Lysine 87 in the beta subunit of tryptophan synthase that forms an internal aldimine with pyridoxal phosphate serves critical roles in transimination, catalysis, and product release

This study provides valuable insights into the functions of the lysine residue that forms an internal aldimine with pyridoxal phosphate in the beta subunit of tryptophan synthase from Salmonella typhimurium. Our spectroscopic and kinetic studies demonstrate that a mutant alpha 2 beta 2 complex having beta subunit lysine 87 replaced by threonine forms external aldimines with several amino acids including L-serine, beta-chloro-1-alanine, L-tryptophan, and D-tryptophan. Because the rates of aldimine formation are very slow, we conclude that one role of lysine 87 in the wild type enzyme is to facilitate formation of external aldimines by transimination. Lysine 87 is an essential catalytic residue because the mutant alpha 2 beta 2 complex has no measurable activity in reactions catalyzed by the beta subunit and does not convert external aldimines to products. The mutant enzyme carries out two slow partial beta-elimination reactions: the conversion of beta-chloro-L-alanine and L-serine to enzyme-bound aminoacrylate. The reaction with L-serine is catalyzed by ammonia, which partially replaces the deleted epsilon-amino group. Lysine 87 is important for substrate and product release because L-serine, L-tryptophan, and aminoacrylate dissociate very slowly from the mutant alpha 2 beta 2 complex. Our ability to prepare very stable derivatives of the mutant alpha 2 beta 2 complex containing tightly bound aldimines with a substrate, a product, or a reaction intermediate provides valuable materials for ongoing x-ray crystallographic investigations and future kinetic analyses of the allosteric activation of the alpha subunit by beta subunit ligands.

Circadian rhythm of rat spleen cytoplasmic thymidine kinase

The activity of thymidine kinase (TK, EC 2.7.1.21), the first enzyme of the thymidine phosphorylation pathway, was measured at various times over a 24-hr period in the spleens of Sprague-Dawley rats that had been housed under standardized conditions of light and dark for at least 4 weeks before the study. Spleen cytoplasmic TK activity was assayed with [2-14C]thymidine as substrate. Under "normal" light conditions (lights on 6:00 a.m.-6:00 p.m. and lights off 6:00 p.m.-6:00 a.m.), a circadian variation of TK activity was observed (P < 0.0001), Cosinor analysis) with peak activity (1.98 nmol product/hr/mg protein) at 1:00 a.m. (19 hr after light onset, HALO) and trough activity (0.40 nmol product/hr/mg protein) at 1:00 p.m. (7 HALO). Maximum enzyme activity exceeded minimum activity by approximately 5-fold. Reversing the light-dark cycle resulted in a corresponding shift in TK activity. Under these "reverse" conditions (lights on 6:00 p.m.-6:00 a.m. and lights off 6:00 a.m.-6:00 p.m.), a circadian variation in TK activity was also observed (P < 0.0001, Cosinor analysis) with peak activity (1.14 nmol product/hr/mg protein) at 12:00 noon (18 HALO) and trough activity (0.32 nmol/hr/mg protein) at 12:00 a.m. (6 HALO). Maximum enzyme activity exceeded minimum activity by approximately 4-fold. In summary, this study demonstrated for the first time that TK activity varies over a 24-hr period in association with the light-dark cycle.

Investigations of kinase substrate specificity with aqua Rh(III) complexes of adenosine 5'-triphosphate

In this paper the substrate activities and binding affinities of the stereoisomers of the beta,gamma-bidentate Rh(H2O)4ATP and alpha,beta, gamma-tridentate Rh(H2O)3ATP complexes toward selected members of the kinase family of enzymes are reported. Hexokinase and glycerokinase were found to be specific for the delta beta, gamma-bidentate Rh(H2O)4ATP isomer as substrate while adenylate kinase was found to specifically catalyze the reaction of the delta beta,gamma-bidentate Rh(H2O)4ATP isomer. Pyruvate kinase recognized both the delta beta,gamma-bidentate Rh(H2O)4ATP isomer and the delta beta-P, exo alpha-P alpha,beta,gamma-tridentate Rh(H2O)3ATP isomer as substrates in the catalyzed phosphorylation of the alternate substrate, glycolate. 31P NMR analysis of the respective product complexes showed that alpha-P phosphoryl ligand exchange had not preceded or followed catalysis. Creatine kinase was found to be specific for the delta beta-P, exo alpha-P alpha,beta,gamma-tridentate Rh(H2O)3ATP isomer. Discrimination of the Rh(H2O)nATP isomers via preferential binding of the substrate-active isomer was observed for hexokinase and adenylate kinase but not for glycerokinase, fructose-6 phosphate kinase, creatine kinase, arginine kinase, or acetate kinase.

Thymic carcinoid tumor--a report of 7 cases

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

[An investigation of the effect of rostral ventrolateral medulla lesion on pressor response induced by electrical stimulation of hypothalamic paraventricular nucleus in the cat]

The experiments were performed on 20 adult cats anesthetized with chloralose and urethane, paralyzed and artificially ventilated. The rostral ventrolateral medulla (RVL) was explored by electrical stimulation. We found that an area, 3-5 mm rostral to the obex, 3-4 mm lateral to the midline, and 0-1 mm from the ventral surface of the medulla, was the most effective region for producing a pressor response. After bilateral microinjection of kainic acid into or electrolytic lesion of the above-mentioned active RVL area, a large decrease in arterial blood pressure was elicited, and the pressor response induced by electrical stimulation of the hypothalamic paraventricular nucleus (PA) was nearly eliminated. The results suggest that the RVL mediates the PA pressor response.

[Study on the color modification buring surface staining of PLAT castable ceramic restorations]

The surface staining of castable ceramic restorations is a technique-dependent process. So it is inevitable that the color of restorations mismatch the color of natural teeth. This study was conducted to explore the possibility of modifying the color by selected use of special colored stains. Eighty PLAT castable ceramic samples were machined, 16 mm in diameter, 1.2 mm in thickness. Thirty-two samples were stained with yellow stain and 32 samples orange. Sixteen samples were stained with red, green, blue and violet stains, respectively. To the yellow and orange stained samples, we applied correspondingly the same stain, red, green, blue and violet stains. The color of each sample was evaluated with a colorimeter and translated to Munsell notations. The results indicated that chroma was intensified by each application of the same stain. Red and green stains made the hue reddish and greenish. Blue and violet stains could effectively decrease the chroma of yellow or orange. Meanwhile, the hue was also slightly changed to greenish and reddish.

Clothing prevents ultraviolet-B radiation-dependent photosynthesis of vitamin D3

Photoprotection of the skin is mainly a function of clothing, although the effectiveness of the latter against UV-B solar radiation (wavelengths 290-320 nm) has not been measured in vivo. Since UV-B mediates the cutaneous formation of vitamin D3, we examined the attenuation of that photosynthetic reaction by the commonly used fabrics cotton, wool, and polyester in black and white colors. Direct transmission of UV-B was attenuated the most by black wool (98.6% of incident irradiance) and the least by white cotton (47.7%). None of the fabrics allowed the photoproduction of previtamin D3 from 7-dehydrocholesterol irradiated in vitro with up to 40 min of simulated sunlight or the elevation of serum vitamin D3 after irradiation with approximately one minimal erythema dose (MED) of UV-B in volunteers wearing jogging garments made of these fabrics. Increasing the whole body irradiation dose to six MEDs still failed to produce a serum vitamin D3 response in garment-clad subjects. Regular (seasonal) street clothing also prevented an elevation of the vitamin D3 in response to UV-B radiation. We conclude that clothing prevents or significantly impairs the formation of vitamin D3 after photostimulation with up to six MEDs of UV-B.

Early markers of pancreas transplant rejection

To compare the predictive value of urinary amylase (UA), urinary insulin (UI), and urinary prostaglandin (PGE2), whole pancreas isografts or allografts from (ACI rat donors, RT1a) with bladder drainage of exocrine secretions were performed in Lewis rats (RT1(1)) with streptozotocin-induced diabetes. UA, UI, PGE2 and plasma glucose levels were measured daily. Euglycemia was restored on Postoperative Day 1 in all the recipients of isografts (N = 6) and was maintained for over a year. UI concentrations and PGE2 outputs were stable, with low levels ranging between 0.3 +/- 0.2 to 7 +/- 2 ng/ml and 56 +/- 15 to 164 +/- 48 ng/24 hr, respectively, while UA levels were significantly elevated compared to normal controls (> 1,000 U/ml vs 29 +/- 16 U/ml). In the allograft group (N = 12), rejection occurred on Days 7 through 9, with a mean graft survival time of 8.1 +/- 0.1 days. UA dropped from a post-transplant peak of 2,422 +/- 353 U/ml on Postoperative Day 4 to below 1,380 +/- 256 U/ml 3 days before rejection (Day -3). UI increased to 83 +/- 16 ng/ml (P < 0.05) on Day -6 and reached a post-transplant peak of 140 +/- 24 ng/ml on Day -5, while PGE2 output rose from a pretransplant level of 18 +/- 2 to 92 +/- 25 ng/24 hr on Postoperative Day 1, followed by a significant elevation on Day 4 (-4).(ABSTRACT TRUNCATED AT 250 WORDS)

Hemodynamic observation and treatment approach for patients with angina decubitus

In order to investigate the mechanism and treatment of angina decubitus, 20 patients (18 men and 2 women aged 36-70 years) were studied during hospitalization. All patients were found to have an increased heart rate x systolic blood pressure product before the onset of angina decubitus, indicating that this type of angina pectoris belongs to the category of effort angina. Of the 11 patients investigated by continuous hemodynamic monitoring, 3 had significant progressive increases in pulmonary artery systolic pressure (PASP) and pulmonary artery diastolic pressure (PADP) before onset: their episodes of angina could not be completely controlled by digoxin and diuretics, but quickly subsided after beta blockers were added. Among the other 8 patients, PADP increased slightly in 5 and remained unchanged in 3 cases before onset: these patients had no manifestations of LV dysfunction, and beta blockers combined with coronary vasodilators produced satisfactory effects. These results indicate that LV failure is not a major factor in the pathogenesis of angina decubitus. The LV diastolic dysfunction seen in 8/11 cases may have been related to LV hypertrophy caused by long-term hypertension or chronic persistent ischemia.

Identification of an African swine fever virus gene with similarity to a myeloid differentiation primary response gene and a neurovirulence-associated gene of herpes simplex virus

Here we describe an open reading frame (LMW23-NL) in the African swine fever virus genome that possesses striking similarity to a murine myeloid differentiation primary response gene (MyD116) and the neurovirulence-associated gene (ICP34.5) of herpes simplex virus. In all three proteins, a centrally located acidic region precedes a highly conserved, hydrophilic 56-amino-acid domain located at the carboxy terminus. LMW23-NL predicts a highly basic protein of 184 amino acids with an estimated molecular mass of 21.3 kDa. The similarity of LMW23-NL to genes involved in myeloid cell differentiation and viral host range suggests a role for it in African swine fever virus host range.

[Study on casting precision of plat castable ceramic crowns]

The plat castable ceramic crown was made with investment material prepared in our college with our own casting technique by a Chinese-made casting machine. The accuracy and fitness of the crown were studied and appraised. Results show that the margin of fitness is 46 microns and that the cement film thickness of the dies in the spacer material group is 65.13 microns. Hence the results are satisfactory. The Plat castable ceramic crown might be used in clinical dentistry.

Myelin proteolipid protein: minimum sequence requirements for active induction of autoimmune encephalomyelitis in SWR/J and SJL/J mice

Proteolipid protein (PLP) is the major protein constituent of mammalian central nervous system myelin. We have previously identified two different PLP encephalitogenic T cell epitopes in two mouse strains. Murine PLP peptides 103-116 YKTTICGKGLSATV and 139-151 HCLGKWLGHPDKF are encephalitogenic determinants in SWR/J (H-2q) and SJL/J (H-2s) mice, respectively. The purpose of the present study was to determine the minimum sequence requirements for each of these PLP encephalitogens. In SWR/J mice, at least two distinct overlapping peptides can induce experimental autoimmune encephalomyelitis (EAE). The eleven residue sequences PLP 105-115 TTICGKGLSAT and PLP 106-116 TICGKGLSATV are encephalitogenic in SWR/J mice, but PLP 106-115 TICGKGLSAT, the decapeptide indigenous to both sequences, is non-encephalitogenic. In contrast, the shortest PLP sequence capable of inducing EAE in SJL/J mice is the nonapeptide 141-149 LGKWLGHPD. These data indicate that encephalitogenic determinants of PLP are short contiguous peptide sequences similar in length and diversity to those of MBP.

(Aminoalkoxy)chromones. Selective sigma receptor ligands

A series of (aminoalkoxy)chromones has been prepared, members of which bind potently (16-100 nM) at the sigma binding site and bind weakly (greater than 1000 nM) at the dopamine D2 receptor and 33 other receptors, second messenger systems, and ion channels. At the sigma receptor, the preferred position of attachment for the aminoalkoxy side chain to the chromone ring followed the rank order: 7-position greater than 5-position greater than 6-position. Chromones that contained a 2-substituent that was not coplanar with the chromone ring system showed improved binding over compounds with coplanar substituents. The most potent compound at the sigma site, 7-[[7-(4-hydroxypiperidyl)heptyl]oxy]-2-phenylchromone (74), had receptor affinities (IC50) of 16 nM at the [3H]DTG site, 19 nM at the [3H]-(+)-3-PPP site, and 4000 nM (Ki) at the dopamine D2 receptor. The most selective compound examined, 6-[[6-(4-hydroxypiperidyl)hexyl]-oxy]-2-cyclopentylchromone (58), exhibited IC50s of 51 nM at the [3H]DTG site, 55 nM at the [3H]-(+)-3-PPP site, and 21,000 nM (Ki) at the dopamine D2 receptor. Compound 44 (6-[[6-(4-hydroxypiperidyl)hexyl]oxy]-3-methylflavone, NPC 16377) was systemically effective (ip and po) in two behavioral models predictive of antipsychotic compounds and systemically active in animal models of ischemia.

Effects of Ca2+ on the kinetics of phosphate release in skeletal muscle

The process of phosphate dissociation during the muscle cross-bridge cycle has been investigated by photoliberation of inorganic phosphate (Pi) within skinned fibers of rabbit psoas muscle. This permitted a test of the idea that Ca2+ controls muscle contraction by regulating the Pi release step of the cycle. Photoliberation of Pi from structurally distinct "caged" Pi precursors initiated a rapid tension decline of up to 12% of active tension, and this was followed by a slower tension decline. The apparent rate constant of the fast phase, kPi, depended on both [Pi] and [Ca2+], whereas the slow phase generally occurred at 2-4 s-1. At maximal Ca2+, kPi increased in a nonlinear manner from 43 +/- 2 s-1 to 118 +/- 7 s-1, as Pi was raised from 0.9 to 12 mM. This was analyzed in terms of a three-state kinetic model in which a force-generating transition is coupled to Pi dissociation from the cross-bridge. As Ca(2+)-activated tension was reduced from maximal (Pmax) to 0.1 Pmax, (i) kPi decreased by up to 2.5-fold, (ii) the relative amplitude of the rapid phase increased 2-fold, and (iii) the relative amplitude of the slow phase increased about 6-fold. Changes in the rapid phase are compatible with Ca2+ influencing an apparent equilibrium constant for the force-generating transition. By comparison, kPi was faster than the rate constant of tension redevelopment, ktr, and was influenced less by Ca2+. Ca2+ effects on the caged Pi transient cannot account for the large effects of Ca2+ on actomyosin ATPase rates or cross-bridge cycling kinetics but may be a manifestation of reciprocal interactions between the thin filament and force-generating cross-bridges, and may represent Ca2+ regulation of the distribution of cross-bridges between non-force-and force-generating states.

Enhanced Photosynthesis and Stomatal Conductance of Pima Cotton (Gossypium barbadense L.) Bred for Increased Yield

Yield of Pima cotton (Gossypium barbadense L.) has tripled over the last 40 years with the development of new cultivars. Six genetic lines representing successive stages in the breeding process (one primitive noncultivated accession, four cultivars with release dates from 1949 to 1983, and one unreleased breeding line) were grown in a greenhouse, and their gas exchange properties were compared. Among the cultivated types, genetic advances were closely associated with increasing single-leaf photosynthetic rate (A) and stomatal conductance (g(s)), especially in the morning. The A and g(s) of the primitive line approached those of the cultivated types early in the morning, but were much lower for the rest of the day. In both morning and afternoon, A was correlated with g(s) across genotypes but was not correlated with leaf thickness, concentrations of chlorophyll or starch, or intercellular CO(2) concentration (c(i)). In the oldest cultivar, the relationship of A to c(i) did not change between morning and afternoon. In the two most recent lines, the slopes of the A:c(i) curves at limiting c(i) exceeded that of the oldest cultivar by 25 to 50% in the morning, but the differences were much smaller in the afternoon. The maximum A of the newer lines at high c(i) exceeded that of the oldest cultivar only in the morning. Breeding for increasing yield has enhanced the photosynthetic capacity and stomatal conductance of Pima cotton and altered the diurnal regulation of photosynthesis.

Intravenous recombinant tissue-type plasminogen activator in acute myocardial infarction

The efficacy and safety of intravenously administered recombinant tissue-type plasminogen activator (rt-PA, Boehringer Ingelheim Corp.) was investigated in 10 patients with acute myocardial infarction (AMI). rt-PA was given as a 10 mg bolus dose followed by infusions of 50 mg, 20 mg and 20 mg in three successive hours. All patients underwent baseline coronary angiography before thrombolytic therapy. Ninety minutes after the initiation of rt-PA infusion, recanalization of infarct-related coronary arteries as confirmed by angiography was achieved in 7 patients. The largest reduction in circulating fibrinogen was observed 4 to 6 h after the start of rt-PA infusion--14.3%. Moderate hemorrhage at the sites of arterial puncture occurred in 2 cases, probably as a result of heparin anticoagulation. No other side effects occurred. So rt-PA is an effective and safe thrombolytic agent.

Secondary prevention of myocardial reinfarction with low dose aspirin

A clinical trial of secondary prevention of reinfarction with low dose aspirin is reported. 50 mg aspirin per day was administered in 216 case. 211 cases did not take aspirin or any other antiplatelet agents as a control group. The follow-up periods in the two groups were 19.4 +/- 12.6 mon and 20.7 +/- 13.0 mon, respectively. There were 175 males in the aspirin group and 137 males in the control group. The incidence of reinfarction was reduced by 65% and platelet aggregation was inhibited obviously in the aspirin group as compared to the control group in men, whereas no significant trends were observed in women.

[Isolation and purification of human brain creatine kinase (CK-BB)]

A improved method for isolation and purification of CK-BB from human brain is introduced. CK-BB of fraction IV was purified to approximately 306.9 fold as compared with homogenate of human brain. The specific activity was 322.2 IU/mg protein. The recovery of creatine kinase activity was 52.8%. This fraction was analyzed by SDS-PAGE. It showed a single major band with an estimated molecular weight of 43000 when it stained with coomassie blue. Purity of fraction V was much better than fraction IV, but some CK activity was lost.

Chemical synthesis and surface activity of lung surfactant phospholipid analogs. II. Racemic N-substituted diether phosphonolipids

A series of racemic 16:0 disaturated N-substituted diether phosphonolipid analogs of glycerophospholipids have been synthesized and purified. Isosteric methylene substitution at three of the four ester sites (carboxyl, phosphate) of conventional glycerophospholipids enhanced the hydrophobicity of analog compounds compared with dipalmitoyl phosphatidylcholine (DPPC), the major glycerophospholipid component of lung surfactant. Further substitutions at the nitrogen headgroup also contributed to hydrophobicity/hydrophilicity characteristics, as well as allowing graded variations in headgroup size among the members of the diether phosphonolipid analog series. Interfacial property studies showed that these compounds had significant differences in surface activity characteristics compared with DPPC, including increased adsorption and respreading facility, plus an enhanced ability to generate low surface tension (less than 1 to 4 mN/m) on an oscillating bubble apparatus at 37 degrees C. In addition, pressure-volume mechanical studies in surfactant-deficient excised rat lungs showed that the diether phosphonate analog of DPPC could partially restore pressure-volume characteristics toward normal, both as a pure component and in binary mixtures with palmitoyl-oleoyl phosphatidylglycerol. These findings suggest that selected analog compounds, synthesized with relatively small structural modifications from biologic glycerophospholipids, may have eventual applications as components of synthetic exogenous lung surfactants. Of more immediate importance, analog molecules with defined structural variations are convenient molecular probes for developing structure-surface activity correlates for phospholipid-like surfactants and for investigating the specificity of interactions between glycerophospholipids and other compounds such as proteins.

Chemical synthesis and surface activity of lung surfactant phospholipid analogs. III. Chiral N-substituted ether-amide phosphonolipids

A homologous series of chiral (R) ether-amide phosphonolipid analogs of naturally occurring (R) glycerophospholipids were synthesized and characterized for their interfacial behaviors. The phosphonolipids possess isoteric ether, amide, and phosphonate functions at positions corresponding to the sn-1, sn-2, and sn-3 ester functions, respectively, of naturally occurring glycerophospholipids. All compounds were synthesized with disaturated C16:0 alkyl/acyl moieties to give structural analogy with dipalmitoyl phosphatidylcholine (DPPC), the major glycerophospholipid component of lung surfactant. Further substitutions at the headgroup nitrogen were also used to generate differences in headgroup size and polarity in the synthetic compounds. The surface activity of the ether-amide phospholipids was investigated in terms of adsorption to the air-water interface, together with studies of dynamic respreading after monolayer collapse and surface tension lowering in dynamically compressed spread films and dispersions. Results showed that several ether-amide phosphonolipids had more rapid adsorption and improved dynamic respreading behavior compared to DPPC, plus the ability to lower surface tension into the range of less than 1 to 4 mN/m in spread films and in dispersions under dynamic conditions. In combination with a series of diether phosphonolipids synthetized in a companion study [1], these ether-amide compounds are useful in the development of molecular structure-surface activity correlates for lung surfactant-related materials, and should assist in investigating the specificity of interactions between phospholipids and other pulmonary biological molecules.

Adenosine 5'-triphosphate increases acetylcholine channel opening frequency in rat skeletal muscle

1. The effects of extracellular adenosine 5'-triphosphate (ATP) on the acetylcholine (ACh) channel opening activity was studied in dissociated rat skeletal muscle cells using patch-clamp recording techniques in cell-attached configuration. 2. With 10 microM-ATP in the recording pipette, the spontaneous opening frequency on the the alpha-bungarotoxin-sensitive ACh channel increased significantly from 0.3 to 4.7 s-1, although the opening frequency was not as high as that activated by very low (0.4 microM) ACh concentrations (64 s-1). 3. Spontaneous ACh channel openings, and ATP-associated and ACh-activated channel openings had similar single-channel conductances, 55, 59 and 56 pS, respectively. 4. ATP-associated events and spontaneous ACh channel opening events had similar mean channel open durations (0.6 ms); however, these values were considerably shorter than the duration of ACh-activated events (2 ms). 5. Pre-treatment with alpha-bungarotoxin (100 nM) blocked spontaneous ACh channel openings, ATP-associated openings and ACh-activated openings. 6. When delivered through a separate drug pipette after the formation of a gigaseal, ATP increased ACh-activated single-channel open probability in a dose-dependent fashion. 7. The increase in channel open probability was due primarily to the increase in channel opening frequency. ATP did not significantly alter the mean channel open duration or the single-channel conductance. 8. The ATP analogue adenosine-5'-O-(3-thiotriphosphate) (ATP-gamma-S) also enhanced ACh-activated channel open probability with relatively less potency. ADP, AMP and adenosine (up to 1 mM) did not significantly increase ACh channel open probability. 9. It is concluded that ATP in the micromolar range facilitates both spontaneous and agonist-activated ACh channel opening. The facilitation is due to ATP itself and not to products of ATP hydrolysis. The facilitatory actions of ATP on ACh channels are manifested by the increase in the channel opening frequency, and they may be mediated by an intracellular second messenger.

Adenosine derived from hydrolysis of presynaptically released ATP inhibits neuromuscular transmission in the rat

It has been established that ATP is released from motor nerve terminals and that exogenous ATP depresses end-plate potential (e.p.p.) amplitudes. This study assessed whether presynaptically released ATP reduced e.p.p.s. E.p.p.s in the rat extensor digitorum longus muscle were depressed by exogenous ATP and adenosine. If ATP hydrolysis to adenoisine was blocked, however, ATP had no effect. Addition of theophylline increased e.p.p. amplitude due to removal of the depressant effect caused by ATP contained in the quantal release. This inhibition was absent when the rate of release was reduced by high Mg2+. It is concluded that e.p.p. inhibition is mediated by adenosine derived from presynaptically released ATP.

[Clinical comparative study of intravenous piperacillin sodium or injection of scutellaria compound in patients with pulmonary infection]

In this survey, 60 patients with pulmonary infection (mainly nosocimial pneumonia) were divided into two groups randomly. 30 patients treated by injection of Scutelleria compound and 30 patients by intravenous piperacillin sodium as control. Before treatment there was no significant difference of clinical data between two groups. The total efficacy was evaluated after treatment for one week. 40%, 36.7% were marked effective in corresponding. 33.3%, 40% were effective and 26.7%, 23% were ineffective respectively. Total effective rates were 73.3% and 76.7% in corresponding group. Temperature was average decreased for 7.43 +/- 3.02 and 7.63 +/- 5.79 days, symptoms disappeared or relieved for 11.67 +/- 6.75 days and 11.53 +/- 7.30 days, leucocyte decreased to normal on 9.03 +/- 6.53 days and 10.13 +/- 6.23 days, roentgenographical shadows disappeared or became smaller for 16.1 +/- 7.02 days and 16.1 +/- 9.88 days in corresponding group. There were no side-effect of the functions of liver, kidney and medulla ossium in two groups. In piperacillin sodium group, fungal infection were found in 4 of 30 patients, but there was no any case suffered from fungal infection in injection of Scutelleria compound group. It was suggested that injection on Scutelleria compound is a hopeful preparation and should be studied further.