Reversed phase high performance liquid chromatography of glycopeptides

A practical procedure for isolating and purifying glycopeptides is described, viz. enzymatic hydrolysis-gel permeation chromatography-ion exchange chromatography-reversed phase HPLC. Using this procedure 28 glycopeptides from hen ovalbumin have been isolated some of which hitherto have not been identified. Water was a suitable mobile phase for preparing pure glycopeptides, and control of column temperature was important for good separations and reproducible retention times. Structural confirmation was by fast atom bombardment mass spectrometry.

[Effect of dexamethasone on the levels of plasma beta-endorphin-like-immunoreactivity in intestinal ischemia shock in the dog]

This paper observed the effect of Dexamethasone (Dex) on the levels of plasma Beta-endorphin-like-immunoreactivity (ir-beta-EP) and its correlation with hemodynamics during the shock. Ten adult mongrel dogs were randomized into two groups. Intestinal shock was created by occluding both superior mesenteric artery and vein in the two groups. After two hours of occlusion, the dogs in treated group were given Dex (5 mg/kg) and the dogs in control group were given normal saline. The intestinal vascular obstruction was released four hours later. It was shown that plasma levels of ir-beta-EP in control group were increased significantly during the shock and correlated significantly with deteriorated hemodynamics. In Dex treated group, the levels of plasma ir-beta-EP and ACTH were significantly lower than that in control group, hemodynamics were improved, and the survival times were much longer. Our results suggest that endogenous opiate beta-EP is involved in the cardiovascular pathophysiology of intestinal shock, and the beneficial effects of steroids (Dex) in the treatment of shock are correlated with its suppressing endogenous beta-EP secretion and release.

[The tendencies of research on Chinese materia medica in Japan--establishment of morbid models in animals and their application to research on Chinese materia medica]

This paper presents a survey of some pathologic models on animals established to satisfy the needs of research on Chinese materia medica in Japan over the last several years, e.g., model of blood-stasis syndrome, model of "taiyang" syndrome, model of spleen deficiency syndrome, speeded aging model and two related models, i.e. chronic renal insufficiency and bronchitis. All these models can be used for reference in the experimental research on Chinese materia medica.

Elevated bone aluminum and suppressed parathyroid hormone levels in hypercalcemic dialysis patients

We studied 21 dialysis patients who became hypercalcemic without vitamin D or calcium therapy and compared them to 28 dialysis patients who were not hypercalcemic. In the hypercalcemic group, the mean ionized-calcium level was elevated compared to normal subjects (5.4 +/- 0.4 vs. 4.9 +/- 0.1; p less than 0.001), while the ionized-calcium level in the control dialysis patients was below normal (4.5 +/- 0.4 vs. 4.9 +/- 0.1; p less than 0.001). Bone biopsies were performed in all patients. Two thirds of the hypercalcemic patients had low-turnover osteodystrophy (LTO, predominantly osteomalacia), a fraction significantly higher than in the control dialysis patients (13/21 vs. 8/28, respectively; p less than 0.05). The hypercalcemic patients with LTO had markedly elevated surface bone aluminum (63 +/- 24% of all trabecular surfaces). In contrast, the nonhypercalcemic dialysis patients with LTO and all patients with osteitis fibrosa had minimal surface bone aluminum. Hypercalcemic patients with osteitis fibrosa had a significantly lower mean N-terminal parathyroid hormone (PTH) value than did nonhypercalcemic patients with osteitis fibrosa (149 +/- 81 vs. 278 +/- 135 pg/ml, respectively; p less than 0.005). Both mean values were markedly elevated in comparison with those obtained in normal subjects (16 +/- 5 pg/ml). In contrast, patients with LTO, irrespective of the calcium level, had mean PTH values that were not significantly different from those of normal subjects. A PTH level greater than 100 pg/ml was 95% sensitive and 87% specific for osteitis fibrosa, as demonstrated by histomorphometry in nonhypercalcemic dialysis patients. However, this level was only 62% sensitive and 77% specific for a diagnosis of osteitis fibrosa in hypercalcemic dialysis patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Excessive ATP degradation during hemodialysis against sodium acetate

As the initial step in examining the metabolic basis for acetate intolerance, we have tested the hypothesis that excessive adenosine triphosphate (ATP) degradation occurs during hemodialysis against acetate dialysate (compared with the degree of degradation occurring during dialysis against bicarbonate dialysate). Seven patients undergoing long-term dialysis were infused with carbon 14--labeled 8-adenine, and their response to dialysis against acetate was compared with their response to dialysis against bicarbonate. The following changes were observed. During dialysis against acetate, the mean dialysate uric acid--to-creatinine ratio levels were significantly higher than the mean levels observed after dialysis against bicarbonate (p less than 0.001). The mean dialysate uric acid radioactivity--to-creatinine ratio and inosine, hypoxanthine, and xanthine radioactivity--to-creatinine ratio levels were significantly increased during dialysis against acetate (p less than 0.001). There was no significant change in plasma venous hypoxanthine level, but during dialysis against acetate, the arterial hypoxanthine levels (3.7 +/- 1.6 mumol/L) at 60 minutes were significantly higher than the levels observed after dialysis against bicarbonate (1.4 +/- 0.5 mumol/L) (p less than 0.01). These data provide evidence that excessive ATP degradation occurs during hemodialysis against acetate but not during hemodialysis against bicarbonate dialysate.

Effects of early antigen exposure through lactation on later specific antibody responses in mice

This study characterized totally the effects of early Ag exposure by the suckling route on later specific antibody responses. When mother mice of BALB/c or C57BL/6 strains were injected with deaggregated human gamma-globulin (HGG) immediately after delivery, total amounts of HGG in sera of offspring increased until 2 wk of age. The catabolism of transferred HGG was extremely slow and the half-life was about 3 wk in both strains. Hence, small amounts of Ag in mothers, 0.5 micrograms in C57BL/6 and 50 micrograms in BALB/c, could tolerize their offspring effectively. As these were minimum tolerogenic doses, the strain difference in ease of tolerance induction is apparent already during suckling. The study on timing dependent effects of HGG-specific antiserum on tolerance induction by mothers given 50 micrograms HGG demonstrated that the tolerance is achieved within the 1st wk of lactation in C57BL/6 offspring, but not in BALB/c offspring, and the restoration from the tolerance needs more than 6 wk under circumstances, supposedly, without free Ag. Whereas the tolerance was induced in a dose-dependent manner in each class of antibody, the dissociation of tolerant states between IgM, IgG, and IgE antibody classes was found in C57BL/6 offspring. It is interesting that C57BL/6 offspring were sensitized weakly, but significantly, by mothers given subtolerogenic doses. However, this was not apparent in BALB/c. Thus, the Ag dose and the animal strain are related closely to the consequences of this Ag exposure. The aging of suckling mice within the first 2 wk of life or immunomodulators administered early in life did not seriously affect the consequences. Studies on a cellular basis showed that the tolerance is caused by the selective defect in helper T cell function and the suppressor cell activity is not associated with the mechanisms. This contrasts with other models of oral tolerance.

Effects of early antigen exposure through lactation on later specific antibody responses in mice

This study characterized totally the effects of early Ag exposure by the suckling route on later specific antibody responses. When mother mice of BALB/c or C57BL/6 strains were injected with deaggregated human gamma-globulin (HGG) immediately after delivery, total amounts of HGG in sera of offspring increased until 2 wk of age. The catabolism of transferred HGG was extremely slow and the half-life was about 3 wk in both strains. Hence, small amounts of Ag in mothers, 0.5 micrograms in C57BL/6 and 50 micrograms in BALB/c, could tolerize their offspring effectively. As these were minimum tolerogenic doses, the strain difference in ease of tolerance induction is apparent already during suckling. The study on timing dependent effects of HGG-specific antiserum on tolerance induction by mothers given 50 micrograms HGG demonstrated that the tolerance is achieved within the 1st wk of lactation in C57BL/6 offspring, but not in BALB/c offspring, and the restoration from the tolerance needs more than 6 wk under circumstances, supposedly, without free Ag. Whereas the tolerance was induced in a dose-dependent manner in each class of antibody, the dissociation of tolerant states between IgM, IgG, and IgE antibody classes was found in C57BL/6 offspring. It is interesting that C57BL/6 offspring were sensitized weakly, but significantly, by mothers given subtolerogenic doses. However, this was not apparent in BALB/c. Thus, the Ag dose and the animal strain are related closely to the consequences of this Ag exposure. The aging of suckling mice within the first 2 wk of life or immunomodulators administered early in life did not seriously affect the consequences. Studies on a cellular basis showed that the tolerance is caused by the selective defect in helper T cell function and the suppressor cell activity is not associated with the mechanisms. This contrasts with other models of oral tolerance.

Simultaneous chemotherapy-radiotherapy with prophylactic cranial irradiation for inoperable adeno and large cell lung carcinoma: a Southwest Oncology Group Study

From September 1980 to March 1983, 30 cases were registered in a Southwest Oncology Group Study. Twenty-four cases were evaluable and constitute the basis for this report. Patients were diagnosed with adenocarcinoma or large cell lung carcinoma. Tumors were considered inoperable but able to be encompassed in a single radiotherapy (RT) port. Seventy-two percent of measured tumors were 4 cm in diameter or bigger (range 2 cm to 10 cm). RT was given initially to the primary lung tumor and ipsilateral hilar, mediastinal, and supraclavicular nodes, at 2 Gy per day; total dose was 44 Gy. The areas involved by tumor were boosted with 10 Gy more. Prophylactic cranial irradiation (PCI) was started at the same time with 15 treatments of 2.75 Gy. A 2-week rest period was instituted after the first 11 treatments. Chemotherapy (CT) was given from day 1 which consisted of 5-Flourouracil, 500 mg./M2, (bolus day 1 and 8) Vincristine, 1 mg./M2, and Mitomycin C, 5 mg./M2 both given on day 1. Cycles were repeated at 28 day intervals for 3 cycles and at 6 week intervals for 5 more cycles, or until progression, with persistent disease. Eight cases (33%) achieved complete response (CR), and 5 (21%) partial response (PR). Overall median survival was 37 weeks and 2 years survival was 8%. CR patients had the best chance for long-term survival. Relapses were evenly distributed between extra and intrathoracic sites, with the latter even between the inside and outside the RT field. No patient died with clinical evidence of metastasis to the brain (MB), although one was found to have MB at autopsy. Toxicity was severe in 7 cases (29%) and 2 deaths are considered toxicity related. When comparing these results to those from the literature, we found this protocol has achieved a slightly higher CR rate than what is expected with RT alone, without survival improvement. As CR patients have the best prognosis, simultaneous CT-RT might offer some promise, but at the expense of increased toxicity. PCI was effective in preventing or delaying MB, and thus deserves further investigation. We should caution that the study of possible long-term effects of PCI could not be assessed because of the short median survival of the patients. It is possible that a less aggressive time-dose fractionation to the brain might be as effective as the one used in this protocol.

Antiarrhythmic potential of chloroquine: new use for an old drug

Amiodarone and chlorpromazine are phospholipase inhibitors which produce cytoplasmic inclusion bodies and have important electrophysiologic properties. Chloroquine also inhibits phospholipase activity, resulting in similar inclusion bodies, but electrophysiologic information about this drug is lacking. In this study, the cellular electrophysiologic effects of two doses of chloroquine were examined in sheep Purkinje fibres and ventricular muscle cells. Both concentrations produced a significant reduction in maximum velocity of upstroke of the action potential and prolongation of the action potential duration and refractory period in Purkinje fibres. These effects were observed in the absence of significant changes in threshold of stimulation or action potential amplitude and were partially reversible following washout of the lower drug concentration. In addition to these experimental data, clinical evidence of antiarrhythmic action was determined by administering 500 mg chloroquine daily over nine weeks to six subjects with frequent asymptomatic ventricular premature complexes. In four patients there was a reduction in ventricular ectopy, which recurred when the drug was discontinued, while a fifth patient reverted to sinus rhythm from atrial fibrillation previously resistant to other antiarrhythmic medication. Thus, chloroquine has important electrophysiologic properties. The underlying mechanism of this action remains unproven at the present time.

Fractures and vertebral bone mineral density in patients with renal osteodystrophy

We investigated the relationship of CT determined vertebral bone mineral density (BMD), type of renal osteodystrophy, N terminal PTH levels and fracture history in 31 dialysis patients. BMD for patients with bone biopsy documented osteitis fibrosa was 1.6 standard deviation (SD) above the normal value for age and sex matched controls, while those patients with low turnover osteodystrophy had a mean BMD 1.2 SD below normal (p less than 0.0001). Three patients with osteitis fibrosa who had previously been treated with prednisone had a low BMD (1.8 SD below normal, different than O, p = 0.0015). There was no correlation between BMD and time on dialysis (r = 0.1). An N terminal PTH level greater than 150 pg/ml was a sensitive (94%) and specific (100%) method of separating those patients with osteitis fibrosa from those with low turnover osteodystrophy, while BMD was much less useful in this differentiation. A low BMD was not predictive of fracture history but the type of renal osteodystrophy was. Patients with low turnover osteodystrophy had a fracture rate of 0.2 fractures/dialysis year in comparison to those with osteitis fibrosis who had 0.1 fractures/dialysis year. Patients with the former bone disease fractured mainly axial rather than appendicular bones in contrast to those patients with osteitis fibrosa. In conclusion we found that patients with osteitis fibrosa had increased BMD compared to normal while those with low turnover osteodystrophy had decreased BMD, but that the N terminal PTH level was a better predictor of the type of bone disease present than was BMD.

CheA protein, a central regulator of bacterial chemotaxis, belongs to a family of proteins that control gene expression in response to changing environmental conditions

During bacterial chemotaxis, the binding of stimulatory ligands to chemoreceptors at the cell periphery leads to a response at the flagellar motor. Three proteins appear to be required for receptor-mediated control of swimming behavior, the products of the cheA, cheW, and cheY genes. Here we present the complete nucleotide sequence of the Salmonella typhimurium cheA gene together with the purification and characterization of its protein product. The protein is a 73,000 Mr cytoplasmic constituent. Amino acid-sequence comparisons indicate that it belongs to a family of bacterial regulatory proteins including the products of the cpxA, dctB, envZ, ntrB, phoR, phoM, and virA genes. Each member of this family has a conserved domain of approximately equal to 200 residues within its C terminus. We have previously shown that another chemotaxis protein, CheY, represents a domain of protein structure that has been conserved within a second large family of bacterial regulatory proteins. Each protein of the CheA family seems to function as a regulator of a different CheY homologue. Although each pair of proteins appears to produce a specialized response to a distinct type of stimulus, the relationships in primary structure suggest that a similar molecular mechanism may be involved.

Pressure Buildup Analysis For Wells Influenced By Fractures And Other Heterogeneities

Abstract

A new approach has been devised to analyze pressure buildups in heterogeneous reservoirs. The proposed procedure is a modification of the semi-log straight line plotting of Horner analysis. It is also an improvement over the conventional type curve matching technique in that the effect of flow time, and the rate variations during drawdown, are incorporated. Applications of this procedure to analyze heterogeneities characterized by a linear boundary, natural fractures, and a vertical fracture demonstrate the strength of the approach.

Introduction

The Horner plot(1,2) has been used successfully in the analysis of buildups taken after constant rate drawdowns from infinite acting, homogeneous reservoirs. If all the underlying assumptions are valid, then a plot of shut-in pressure versus the logarithm of the Horner time group results in a straight line. Parametric estimations can be made from the slope and intercept of this line.

Any type of heterogeneity in the reservoir introduces deviations from linearity in such a plot. For mild near wellbore heterogeneities such as wellbore storage or skin, only the early time data is affected. If, however, the duration of the shut-in time is short, then the initial deviation from linearity may cause some uncertainty in determining the start of the semi-log straight line. Ramey(3) introduced the type curve matching technique to resolve this problem. It has been used mainly to detennine the start of the semi-log straight line. Homer analysis is still required for parametric estimation purposes.

In situations with more complex heterogeneities, the deviation from linearity in Homer plots is more serious. In some cases, such as pressure buildups taken from wells intersecting vertical fractures, the data points in a Horner plot curve continuously upward, making the choice of an appropriate semi-log straight line difficult, if not impossible. Clearly, Horner analysis is inadequate in these situations and, instead of being a supporting tool, type curves themselves are being used increasingly for parametric estimation.

Because most of the type curves are a dimensionless pressure solution to the constant rate drawdown boundary condition, their use for buildup analysis requires an extra assumption of the total flow time being much longer than the shut-in time. When this assumption is not valid, McKinley(4), and Raghaven(5) suggested using buildup type curves. Thus, from one single drawdown curve it is necessary to generate a number of buildup type curves for different flow times. As the number of drawdown type curves multiplies, the choice of a best match among the multitude of buildup curves is not an easy one.

Another problem associated with the constant rate assumption is that it can be impractical to maintain the rate constant during the field test. Bostic et. al.(6) attempted to modify the drawdown type curves to take into account rate variations. Their derivation, however, depends on an erroneous substitution of the measured pressure into the dimensionless pressure. Hence the subsequent derivation cannot be used.

Recently, Rosa and Horne(7), Kucuk et al.(8), and Lee and Brockenbrough(9) devised least squares optimization schemes to resolve the above-mentioned problems with type curve matching.

Sequence requirements of Escherichia coli attTn7, a specific site of transposon Tn7 insertion

Transposon Tn7 transposes at high frequency to a specific site, attTn7, in the Escherichia coli chromosome. We devised a quantitative assay for Tn7 transposition in which Tn7-end derivatives containing the cis-acting transposition sequences of Tn7 transpose from a bacteriophage lambda vector upon infection into cells containing the Tn7-encoded transposition proteins. We used this assay to identify a 68-base-pair DNA segment containing the sequences essential for attTn7 target activity. This segment is positioned asymmetrically with respect to the specific point of Tn7 insertion in attTn7 and lacks obvious homology to the sequences at the ends of Tn7 which participate directly in transposition. We also show that some sequences essential for attTn7 target activity are contained within the protein-coding sequence of a bacterial gene.

Combined chemoradiotherapy in limited-disease, inoperable non-small cell lung cancer

Forty-three patients with limited-disease, inoperable non-small cell lung cancer received two intravenous courses of cyclophosphamide, Adriamycin, and cisplatin (CAP) chemotherapy over a 6-week period. This was followed by 5 weeks of combined chemoradiotherapy (CCRT) consisting of low weekly doses of CAP for 5 weeks plus 50 Gy continuous X ray therapy (XRT) to the primary tumor site. Chemotherapy was continued until disease progression occurred or until the total dose of Adriamycin reached 450 mg/m2, whichever came first. CCRT improved the response rate [complete response (CR) plus partial responses (PR)] from 25% after two courses of CAP alone to 65% after CCRT. Previous response to two courses of CAP influences response subsequent to CAP plus XRT. A pretherapy weight loss of 6% or greater had a significant adverse effect on both response and survival time. The median survival time for all patients was 50 weeks; patients whose disease responded to treatment survived significantly longer than patients with nonresponding disease. The median time until disease progression was 37 weeks. Twenty-seven patients relapsed. The first sites of relapse were local in 30% of the patients, distant in 56% of them, and both local and distant in 15%. Severe esophagitis occurred in 30% of the patients and was dose-limiting. The administration of CCRT resulted in an improved response rate compared with the rates reported in previous studies of chemotherapy or radiotherapy alone. Further improvement of the CCRT program is needed to increase long-term survival time and to decrease esophageal toxicity.

The welfare effects of illegal immigration

"This paper extends the work of Ethier on illegal immigration by examining the optimal level of enforcement for the labor-importing country in a two-country model and by considering the effects of allowing capital mobility. We derive a formula for the optimal level of enforcement against firms that hire illegal workers, and show that the presence of enforcement costs makes the policy less efficient than a wage tax. With capital mobility, foreign workers gain from an increase in enforcement in the home country because capital is driven out of the home country."

Kinetics of procaterol auto-oxidation in buffered acid solutions

The kinetics of procaterol (1) degradation in buffered acidic solutions (pH 4-6) was investigated using an HPLC procedure. The effect of temperature and ferric ions on the reaction rate was estimated. In acidic solutions, 1 undergoes pseudo first-order degradation with an induction period. The first-order rate constant for degradation increased and the induction period decreased with an increase in pH. Ferric ions catalyzed the degradation reaction and decreased the induction period. At pH 6, the activation energy of the reaction was 34.5 kcal/mol/deg. The results of this study indicate that 1 in solution is more stable at acidic pH, in the absence of heavy metal ions, and protected from air.

Immunochemical probing of the N-terminus of the myosin heavy chain

The reactivity of myosin subfragment 1 (S-1) towards site specific polyclonal anti-N-terminus antibodies was examined in competitive ELISA titrations. Tryptic digestion of S-1 and specifically the cleavage at the 25/50K junction greatly increased the accessibility of the N-terminus region to the antibodies. The binding of actin to S-1 did not change significantly the reactivity of either tryptic or intact S-1 towards anti-N-terminus antibodies. These results suggest the interdependence of the N-terminus and 25/50K junction regions on S-1.