High-performance liquid chromatographic column-switching method for two cyclosporine metabolites in blood

Cyclosporine (CSA) is biotransformed to many metabolites which may contribute to its immunosuppressive and nephrotoxic activity. We report a rapid and sensitive, automated column-switching high-performance liquid chromatographic (HPLC) method for measuring CSA-M17 in whole blood; the method also separates CSA-M1. CSA metabolite standards were isolated by a preparative-scale HPLC method. Samples were prepared by protein precipitation with acetonitrile followed by dilution with water. CSA-M17 was initially separated on a C8 column; final separation was on a C18 column. The inter-day relative standard deviation at 50 ng/ml was 8% (n = 3). Limit of detection was 20 ng/ml.

Bottle- and breast-feeding: effects on transcutaneous oxygen pressure and temperature in preterm infants

Transcutaneous oxygen pressure (tcPO2) and body temperature were monitored for the duration of feeding sessions in five small preterm infants who served as their own controls for bottle-feeding (BoF) and breast-feeding (BrF). Longitudinal data were collected twice weekly for BoF and BrF sessions from infants' first oral feeding until discharge, for a total of 71 feeding sessions: 32 BoF and 39 BrF. Markedly dissimilar for the two feeding methods, tcPO2 patterns suggested less ventilatory interruption during BrF than BoF. Sequential tcPO2 values at baseline, immediately postfeed, and 10 minutes postfeed were significantly different for the feeding methods, with greater declines for BoF. Maximal temperature change, calculated by subtracting the baseline from the most extreme temperature for each feeding session, indicated that infants became significantly warmer during BrF than BoF. Although the small sample size necessitates replication, these results do not support the widely held assumption that BrF is more stressful than BoF for small preterm infants.

[SGPT determination as a routine screening procedure in blood donors?]

Liver biopsy was carried out in 103 patients with elevated transaminases. In 46 patients (44.5%) histological examination produced the diagnosis of a chronic persistent non-A, non-B hepatitis, whereas in 57 patients (55.5%) steatosis was found. Laboratory findings showed that SGOT is of little use in distinguishing these two diseases. SGPT and the SGOT/SGPT quotient indicate the existence of a CPH-NANB in 93.5 and 89% respectively. We therefore conclude that SGPT should be determined in all blood donors as indirect screening to identify carriers of NANB.

[Aorto-esophageal fistula: late complications following aortic graft implantation]

Aorto-esophageal fistula is a rare complication after repair of thoracic aortic aneurysm. In a review of the literature only 3 cases have been found. A fourth case is reported which was diagnosed preoperatively by endoscopy.

Integral membrane proteins significantly decrease the molecular motion in lipid bilayers: a deuteron NMR relaxation study of membranes containing myelin proteolipid apoprotein

The influence of the myelin proteolipid apoprotein on lipid chain order and dynamics was studied by 2H NMR of membranes reconstituted with specifically deuterated dimyristoyl phosphatidylcholines. Quadrupolar echo and saturation recovery experiments were fitted by numerical solution of the stochastic Liouville equation, using a model that includes both inter- and intramolecular motions [Meier, P., Ohmes, E. & Kothe, G. (1986) J. Chem. Phys. 85, 3598-3614]. Combined simulations of both the relaxation times and the quadrupolar echo line shapes as a function of pulse spacing allowed unambiguous assignment of the various motional modes and a consistent interpretation of data from lipids labeled on the C-6, C-13, and C-14 positions of the sn-2 chain. In the fluid phase, the protein has little influence on either the chain order or the population of gauche rotational isomers but strongly retards the chain dynamics. For 1-myristoyl-2-[13-2H2] myristoyl-sn-glycero-3-phosphocholine at 35 degrees C, the correlation time for chain fluctuation increases from 20 nsec to 650 nsec and for chain rotation from 10 nsec to 180 nsec, and the gauche isomer lifetime increases from 0.15 nsec to 1.75 nsec, on going from the lipid alone to a recombinant of protein/lipid ratio 0.073 mol/mol. The results are essentially consistent with spin-label ESR studies on the same system [Brophy, P.J., Horvath, L.I. & Marsh, D. (1984) Biochemistry 23, 860-865], when allowance is made for the different time scales of the two spectroscopies.

Proton Spin Relaxation Study of Molecular Motions in the Lyotropic Liquid Crystalline System Potassium-Laurate Water

The paper presents and discusses measurements of the proton spin T1 relaxation dispersion over a broad frequency range (100 Hz - 300 MHz) in the micellar, hexagonal, cubic and lamellar phases of lyotropic potassium-laurate water mixtures. The results clearly show that in the anisotropic phases (hexagonal, lamellar) T1 at low Larmor frequencies is dominated by liquid crystalline order fluctuations, whereas this relaxation mechanism is negligible or absent in the isotropic phases (micellar, cubic). At medium and high Larmor frequencies the relaxation reflects rotational and translational molecular motions. Using theoretical models from the literature for the three kinds of reorientations the observed frequency and temperature dependences of T1 can be described quantitatively. In contrast to the order fluctuation mechanism the rotational and translational reorientations of individual molecules depend only weakly on the mesogenic structure. The order fluctuation contribution is strongest for the lamellar phase.

The case study: a viable approach to clinical research

The case study, although associated with several misconceptions which compromise its effective utilization, is especially appropriate for investigation of clinical nursing problems. A literature review of the application of this research approach in other practice-based disciplines was completed. Results indicate that the case study permits focusing upon the individual in an intensive, longitudinal perspective, and facilitates bridging of the research-practice gap. Internal and external validity, considered especially problematic in case studies, can be maximized by a variety of techniques.

[Fibrolamellar hepatoma]

Unlike hepatocellular hepatoma (HCC), the so-called fibrolamellar hepatoma (FLH) is found almost exclusively in the non-cirrhotic, non-infected liver. Patient characteristics and the course of the disease in FLH differ markedly from HCC. FLH represents only a small portion of hepatomas in general (approx. 2%), but accounts for over 40% of hepatomas in young adults. We present the case of a 38-year-old woman showing the typical histological findings of polygonal eosinophilic tumor cells and characteristic lamellar bundles of fibrous stroma, which led to the diagnosis of FLH. The approx. 140 cases of FLH published in the world literature are also presented and discussed. The usefulness of additional examinations (neurotensin, vitamin B12 binding capacity and copper stains) is mentioned. The difficulty in diagnosing FLH lies in its histological differentiation from focal nodular hyperplasia. When diagnosed early, however, FLH is characterized by good resectability with a chance of cure or at least a markedly better survival rate than HCC.

[Detection of wheat gliadins in heated food by reversed-phase high-pressure liquid chromatography]

To recognize and determine the wheat gliadins in unheated gluten-free food for coeliac patients the immunological methods such as ELISA can be used. In heated food (above 80 degrees-90 degrees C) these methods fail wholly or in part to achieve the quantitative determination of wheat gliadin. The changes in protein patterns after heat treatment are also revealed by the RP-HPLC of wheat gliadins and some peaks appear, which are characteristic for heat treated wheat flour. Using these peaks, about 2% admixture of wheat flour (T. aestivum, T. durum) as well as of rye flour can be detected. In foods which contain more than 50% skim milk the addition of only at least 5% of these flours can be detected. The ethanolic extracts of foods were concentrated by freeze-drying prior to analysis by HPLC. The ethanol-soluble non-dialysable food components affect the quantitative determination of wheat or rye proteins by means of peak areas. Selective enrichment is a possibility. The RP-HPLC-analysis of ethanol-soluble proteins makes it possible to detect heated flours of wheat and rye (cooked, roller-dried, extrusion-cooked) in glutenfree food.

Specific skeletal dysplasias in utero: sonographic diagnosis

A retrospective study was performed of 13 short-limbed fetuses with lethal skeletal dysplasias that were evaluated with ultrasound (US) from 1981 to 1984. The specific diagnoses were thanatophoric dwarfism, achondrogenesis, osteogenesis imperfecta, and campomelic dwarfism. Death occurred in utero or within 2 weeks after delivery in all cases. US examination showed other associated abnormalities, including polyhydramnios, hydrops, shortened femurs, and CNS abnormalities. Radiographs confirmed these findings and provided more information regarding the shape of the limbs and thorax and the appearance of the spine. The probable diagnosis of lethal short-limbed dwarfism was made antenatally using US in eleven of the fetuses. Spinal appearance, thoracic shape, and associated hydrops and polyhydramnios were most helpful in determining the specific type of dysplasia present. Lethal short-limbed skeletal dysplasia may be diagnosed confidently in utero using US examination; however, obstetric plain film radiography may be required to determine the definitive type of dysplasia. In certain cases, US may be sufficient to make a definitive diagnosis.

The limitations to and valid use of C-peptide as a marker of the secretion of insulin

The accuracy with which the secretion rate of insulin can be calculated from peripheral concentrations of C-peptide was investigated in conscious mongrel dogs. Biosynthetic human C-peptide and insulin were infused intraportally and their concentrations measured in the femoral artery. During steady-state infusions of C-peptide, the peripheral concentration changed in proportion to the infusion rate and the metabolic clearance rate (5.2 +/- 0.3 ml/kg/min) remained constant over a wide range of plasma concentrations. Application of a two-compartment mathematical model, in which the model parameters were estimated from analysis of C-peptide decay curves after intravenous bolus injections, allowed the intraportal infusion rate of C-peptide to be derived from peripheral C-peptide concentrations, even under non-steady-state conditions. Estimates of the intraportal infusion rate based on this model were 102.4 +/- 2.6% of the actual infusion rate as it was increasing and 102.3 +/- 5.5% of this rate as it was falling. The peripheral C-peptide: insulin molar ratio was influenced by the rate at which equimolar intraportal infusions of C-peptide and insulin were changed. The baseline C-peptide: insulin molar ratio (4.1 +/- 0.9) increased to peak values of 8.2 +/- 0.6, 10.3 +/- 2.0, and 14.9 +/- 1.3 when the infusion rate was increased and then decreased rapidly. Peak values of only 5.7 +/- 1.2 were found if the intraportal infusion rate was changed slowly.(ABSTRACT TRUNCATED AT 250 WORDS)

Persantine-Aspirin Reinfarction Study. Part II. Secondary coronary prevention with persantine and aspirin

In the Persantine-Aspirin Reinfarction Study, Part II (PARIS II), 3,128 persons who had recovered from myocardial infarction, suffered from 4 weeks to 4 months previously, were randomized into two groups: dipyridamole (Persantine) plus aspirin (n = 1,563) and placebo (n = 1,565). The average length of follow-up was 23.4 months. Prespecified primary end points were coronary incidence (definite nonfatal myocardial infarction plus death due to recent or acute cardiac event), coronary mortality (death due to recent or acute cardiac event) and total mortality, each at 1 year of patient follow-up and at the end of the study. Coronary incidence in the Persantine plus aspirin group was significantly lower than in the placebo group, both at 1 year (30% reduction) and at the end of the study (24% reduction). The statistically significant differences in coronary incidence, at 1 year and at the end of the study, in favor of the combination treatment remained after adjustment for multiple baseline variables and adjustment for multiple testing (three end points for two time periods). Although there were reductions for other end points, these differences were not statistically significant. Coronary mortality was 20% lower in the Persantine plus aspirin group compared with the placebo group at 1 year, and 6% lower overall. Total mortality in the treated group compared with the placebo group was 11% lower at 1 year and 3% lower overall. The reduced rates of coronary incidence largely reflected lower rates of definite nonfatal myocardial infarction in the Persantine plus aspirin group. Several subgroups were defined a priori and at the end of the study. The beneficial effect of Persantine plus aspirin compared with placebo for coronary incidence tended to be greater for the following groups of patients: those who had a non-Q wave infarct; those who were not taking digitalis; those who were receiving beta-receptor blocking drugs at baseline; those who were in New York Heart Association functional class I; those who had had only one myocardial infarction; or those who were enrolled in the study early, that is within 85 days of the qualifying myocardial infarction.

Electron spin resonance study of phospholipid membranes employing a comprehensive line-shape model

The electron spin resonance spectra of the 1-myristoyl-2-[6-(4,4-dimethyloxazolidine-N-oxyl)myristoyl]-sn-glycero- 3-phosphocholine spin-label in highly oriented, fully hydrated bilayers of 1,2-dimyristoyl-sn-glycero-3-phosphocholine have been studied as a function of temperature and magnetic field orientation. The oriented spectra show clear indications of slow motional components (rotational correlation times greater than 3 ns) even in the fluid phase (T greater than 23 degrees C), indicating that motional narrowing theory is not applicable to the spectral analysis. The spectra have been simulated by a comprehensive line-shape model that incorporates trans-gauche isomerization in addition to restricted anisotropic motion of the lipid long molecular axis and that is valid in all motional regimes. In the gel (L beta') phase the spin-label chains are found to be tilted at 28 degrees with respect to the normal of the orienting plane. In the intermediate (P beta') phase there is a continuous distribution of tilt angles between 0 degrees and 25 degrees. In fluid (L alpha) phase there is no net tilt of the lipid chains. The chains rotate at an intermediate rate about their long axis in the fluid phase (tau R,parallel = 1.4-6.6 ns for T = 50-25 degrees C), but the reorientation of the chain axis is much slower (tau R, perpendicular= 13-61 ns for T = 50-25 degrees C), whereas trans-gauche isomerization (at the C-6 position) is rapid (tau J less than or equal to 0.2 ns). Below the chain melting transition both chain reorientation and chain rotation are at the ESR rigid limit (tau R greater than or equal to 100 ns), and trans-gauche isomerization is in the slow-motion regime (tau J = 3.7-9.5 ns for T = 22-2 degrees C). The chain order parameter increases continuously with decreasing temperature in the fluid phase (SZZ = 0.47-0.61 for T = 50-25 degrees C), increases abruptly on going below the chain melting transition, and then increases continuously in the intermediate phase (SZZ = 0.79-0.85 for T = 22-14 degrees C) to an approximately constant value in the gel phase (SZZ congruent to 0.86 for T = 10-2 degrees C).(ABSTRACT TRUNCATED AT 400 WORDS)

[Analysis of whole gliadin from untreated and heat-treated flour with phase inversion high pressure liquid chromatography]

The gliadins from various wheat flours either untreated or heated (baking, cooking, roller-drying, extrusion-cooking) were extracted with 70% ethanol and analysed by RP-HPLC. When flours are heated below 80 degrees C the chromatograms showed no significant change. At temperatures about 80-90 degrees C a peak appeared in all samples (with the exception of durum wheat) at a retention time of 35 min (peak 35) or, if already present, become more pronounced. A further increase in temperature or treatment time resulted in an increase in this peak whereas the peaks of the more strongly bound gliadins slowly disappeared. In the gliadins of the bread crust the amount of peak 35 decreased again. Similarly, changes were observed in the distribution of the apparent molecular weights of gliadins from heated flours by using gel electrophoresis (SDS-PAGE). At temperatures about 80-90 degrees C the bands between 50-62 kD (under reducing conditions) appeared or become stronger. Their intensity increased with increasing time and treatment temperature whereas the lower molecular weight bands slowly disappeared. Peak 35 may be useful as an indicator of gliadin in heat-treated "gluten-free" foods.

A controlled trial of extended radical mastectomy

One hundred twenty-three women younger than 70 years of age and at clinical Stages I or II were enrolled in a randomized clinical trial of radical versus extended radical mastectomy. The 5-year survival rates in the radical and extended radical groups were 75 +/- 6.7% and 80 +/- 6.7%, respectively. (Cox P value for comparison of survival curves = 0.32.) Of the total series, 112 were treated by the same surgeon and confirmed pathologically as having invasive mammary carcinoma. In this more homogeneous subgroup, the 5-year survival rates for the radical and extended radical groups were 71 +/- 7.6% and 85 +/- 6.2%, respectively (P = 0.09). For patients from this subgroup with central or medial tumors, the 5-year survival rates were 66 +/- 10% and 88 +/- 8.2%, respectively (P = 0.06). For patients with lateral tumors, the 5-year survival rates were nearly equal: 79 +/- 11% and 81 +/- 9.7%, respectively. The findings in a nonrandomized series of similar patients were comparable. The results are not definitive, but suggest an advantage of extended radical mastectomy over radical mastectomy for patients with central or medial tumors. Continued follow-up of the randomized series may lead to more conclusive results.