Targeting Manganese Amidinates and ß-Ketoiminates Complexes as Precursors for Mn-Based Thin Film Vapor Deposition

With a focus on Mn based organometallic compounds with suitable physico-chemical properties to serve as precursors for chemical vapor deposition (CVD) and atomic layer deposition (ALD) of Mn-containing materials, systematic synthetic approaches with ligand variation, detailed characterization, and theoretical input from density functional theory (DFT) studies are presented. A series of new homoleptic all-nitrogen and mixed oxygen/nitrogen-coordinated Mn(II) complexes bearing the acetamidinate, formamidinate, guanidinate and ß-ketoiminate ligands have been successfully synthesized for the first time. The specific choice of these ligand classes with changes in structure and coordination sphere and side chain variations result in significant structural differences whereby mononuclear and dinuclear complexes are formed. This was supported by density functional theory (DFT) studies. The compounds were thoroughly characterized by single crystal X-ray diffraction, magnetic measurements, mass spectrometry and elemental analysis. To evaluate their suitability as precursors for deposition of Mn-based materials, the thermal properties were investigated in detail. Mn(II) complexes possessing the most promising thermal properties, namely Bis(N,N´-ditertbutylformamidinato)manganese(II) (IV) and Bis(4-(isopropylamino)pent-3-en-2-onato)manganese(II) (ßIII) were used in reactivity studies with DFT to explore their interaction with oxidizing co-reactants such as oxygen and water which will guide future CVD and ALD process development.

Risk factors for respiratory failure among hospitalized patients with Guillain-Barré syndrome

BACKGROUND

Guillain-Barré syndrome (GBS) is an acute inflammatory polyneuropathy that can lead to respiratory failure. In this study, we evaluate early clinical risk factors for respiratory failure at the time of hospital admission.

METHODS

We studied a retrospective cohort of patients with GBS admitted to a tertiary care center. The potential risk factors studied were sociodemographic characteristics, GBS symptoms, overall and cervical muscle weakness (Medical Research Council [MRC] scores), electromyography findings, and cerebrospinal fluid analysis findings. Unadjusted odds ratios (OR) were calculated and exact logistic regression analysis (adjusted OR) performed to assess the association between baseline risk factors and respiratory failure.

RESULTS

Overall, 13 of 113 (12%) patients included in the study developed respiratory failure. Unadjusted analyses showed that involvement of any cranial nerve (OR: 14.7; 95% CI, 1.8-117.1), facial palsy (OR: 17.3; 95% CI, 2.2-138.0), and bulbar weakness (OR: 10.7; 95% CI, 2.3-50.0) were associated with increased risk of respiratory failure. Lower MRC sum scores (for scores <30, OR: 14.0; 95% CI, 1.54-127.2) and neck MRC scores (for scores ≤3, OR: 21.0; 95% CI, 3.5-125.2) were associated with higher likelihood of respiratory failure. Adjusted analyses showed that presence of bulbar weakness (OR: 7.6; 95% CI, 1.3-43.0) and low neck MRC scores (scores ≤3, OR: 9.2; 95% CI, 3.5-125.2, vs scores >3) were independently associated with respiratory failure.

CONCLUSIONS

Bulbar and neck muscle weakness at admission are clinical predictors of increased risk of respiratory failure in patients with GBS. These findings could guide the adequate management of high-risk patients.

CVD Grown Tungsten Oxide for Low Temperature Hydrogen Sensing: Tuning Surface Characteristics via Materials Processing for Sensing Applications

The intrinsic properties of semiconducting oxides having nanostructured morphology are highly appealing for gas sensing. In this study, the fabrication of nanostructured WO₃ thin films with promising surface characteristics for hydrogen (H₂ ) gas sensing applications is accomplished. This is enabled by developing a chemical vapor deposition (CVD) process employing a new and volatile tungsten precursor bis(diisopropylamido)-bis(tert-butylimido)-tungsten(VI), [W(N^t Bu)₂ (Nⁱ Pr₂ )₂ ]. The as-grown nanostructured WO₃ layers are thoroughly analyzed. Particular attention is paid to stoichiometry, surface characteristics, and morphology, all of which strongly influence the gas-sensing potential of WO₃ . Synchrotron-based ultraviolet photoelectron spectroscopy (UPS), X-ray photoelectron spectroscopy (XPS), X-ray photoelectron emission microscopy (XPEEM), low-energy electron microscopy (LEEM) and 4-point van der Pauw (vdP) technique made it possible to analyze the surface chemistry and structural uniformity with a spatially resolved insight into the chemical, electronic and electrical properties. The WO₃ layer is employed as a hydrogen (H₂ ) sensor within interdigitated mini-mobile sensor architecture capable of working using a standard computer's 5 V 1-wirebus connection. The sensor shows remarkable sensitivity toward H₂ . The high, robust, and repeatable sensor response (S) is attributed to the homogenous distribution of the W⁵⁺ oxidation state and associated oxygen vacancies, as shown by synchrotron-based UPS, XPS, and XPEEM analysis.

Effects of corn distillers grains with yeast bodies and manipulation of dietary cation and anion difference on production, nutrient digestibility, and gas emissions from manure in lactating cows

In a randomized complete block design, 40 lactating Holstein cows (average 98 d in milk and 41 kg/d of milk yield) were randomly assigned to 1 of 4 diets: (1) containing soybean meal as the major protein supplement (CON diet); (2) CON diet with high-protein dried corn distillers grains at 20% on a dry matter (DM) basis by replacing mainly soybean meal (DG diet); (3) DG diet except that high-protein dried corn distillers grains with yeast bodies (extracted after corn ethanol production) was used (DGY diet); or (4) DG diet supplemented with sodium bicarbonate and potassium carbonate to elevate the dietary cation and anion difference (DCAD; DG-DCAD diet). The DCAD of CON, DG, DGY, and DG-DCAD were 185, 62, 67, and 187 mEq/kg of DM, respectively. The experiment began with a 10-d covariate period and then cows were fed the experimental diets for 5 wk (2-wk diet adaptation and 3-wk data collection periods). Dry matter intake and milk yield were measured daily, and spot urine and fecal samples were collected in the last week of the experiment to measure nutrient digestibility; N, S, and P utilization and excretion; and in vitro NH₃ and H₂S emissions from manure. All data were analyzed using the MIXED procedure of SAS (random effect: block; fixed effects: diets, repeated week, and interactions). During data collection, DM intake was not different among treatment groups, but milk yield tended to be lower (42.4 vs. 39.9 kg/d) for DG, DGY, and DG-DCAD versus CON, which could have been caused by decreases in organic matter and neutral detergent fiber digestibility. Milk protein yield tended to be lower (1.33 vs. 1.24 kg/d) for DG, DGY, and DG-DCAD versus CON. Milk fat yield was lower (1.26 vs. 1.55 kg/d) for DG and DGY versus CON, but that for DG-DCAD (1.43 kg/d) did not differ from CON. Similarly, energy-corrected milk was lower (38.0 vs. 43.3 kg/d) for cows on DG and DGY versus those on CON, but it did not differ between DG-DCAD (40.7 kg/d) and CON. Urinary and fecal N excretion were greater for DG, DGY, and DG-DCAD compared with CON due to greater dietary crude protein content and N intake. However, NH₃ emissions did not differ across treatments. Intakes of dietary P and S were greater for DG, DGY, and DG-DCAD, resulting in greater excretion of those in manure and greater H₂S emissions from manure compared with CON. These data suggest that the negative effects of feeding distillers grains on production of lactating cows can be partly explained by a decrease in nutrient digestibility (milk yield) and excessive anion load (milk fat). The milk fat response to DG-DCAD suggests that milk fat depression observed with a diet with high content of distillers grains can be partially alleviated by supplementation of cations. In the current study, we observed no beneficial effects of DG containing yeast bodies.

Risk factors for respiratory failure among hospitalized patients with Guillain-Barré syndrome

BACKGROUND

Guillain-Barré syndrome (GBS) is an acute inflammatory polyneuropathy that can lead to respiratory failure. In this study, we evaluate early clinical risk factors for respiratory failure at the time of hospital admission.

METHODS

We studied a retrospective cohort of patients with GBS admitted to a tertiary care center. The potential risk factors studied were sociodemographic characteristics, GBS symptoms, overall and cervical muscle weakness (Medical Research Council [MRC] scores), electromyography findings, and cerebrospinal fluid analysis findings. Unadjusted odds ratios (OR) were calculated and exact logistic regression analysis (adjusted OR) performed to assess the association between baseline risk factors and respiratory failure.

RESULTS

Overall, 13 of 113 (12%) patients included in the study developed respiratory failure. Unadjusted analyses showed that involvement of any cranial nerve (OR: 14.7; 95% CI, 1.8-117.1), facial palsy (OR: 17.3; 95% CI, 2.2-138.0), and bulbar weakness (OR: 10.7; 95% CI, 2.3-50.0) were associated with increased risk of respiratory failure. Lower MRC sum scores (for scores <30, OR: 14.0; 95% CI, 1.54-127.2) and neck MRC scores (for scores ≤3, OR: 21.0; 95% CI, 3.5-125.2) were associated with higher likelihood of respiratory failure. Adjusted analyses showed that presence of bulbar weakness (OR: 7.6; 95% CI, 1.3-43.0) and low neck MRC scores (scores ≤3, OR: 9.2; 95% CI, 3.5-125.2, vs scores >3) were independently associated with respiratory failure.

CONCLUSIONS

Bulbar and neck muscle weakness at admission are clinical predictors of increased risk of respiratory failure in patients with GBS. These findings could guide the adequate management of high-risk patients.

"Intrinsic" elimination rate and dietary intake estimates for selected indicator PCBs: toxicokinetic modeling using serial sampling data in US subjects, 2005-2010

Changes in measured concentrations of persistent compounds such as polychlorinated biphenyls (PCBs) in an individual over time reflect not only intrinsic elimination rates but also any ongoing intake of the compounds and changes in the volume of distribution. Thus, "apparent" elimination rates calculated from data on changes in serum lipid-adjusted concentration may over- or under-estimate the "intrinsic" elimination rates for such compounds. Serum PCB concentrations were measured in 43 individuals approximately 5years apart. Changes in measured concentrations and body weights were used to estimate mass-based apparent elimination rates. The changes in estimated body mass of PCBs 105, 118, 138, 153, and 180 were input into a simple first-order model employing previously estimated intrinsic elimination rates to estimate congener-specific average dietary intake rates over the period between samples. Calculated median dietary intakes were compared to previous estimates. Intrinsic elimination rates were adjusted for two congeners. The analyses support central tendencies of intrinsic elimination rates of approximately 5years for PCBs 105 and 118, 11years for PCB 138, 14.4years for PCB 153, and 20years or more for PCB 180. Estimated dietary intakes for this population and time period depend on the assumed intrinsic elimination rates and range from 0.1ngkg(-1)d(-1) for PCB 105 to approximately 1-2ngkg(-1)d(-1) for PCB 180. Estimated body burdens of PCB 180 changed very little over the five-year period, suggesting near steady-state exposure levels. As a result, estimates for both elimination half-life and ongoing intake rates for this congener are highly uncertain.

Is there a significance of histamine in the control of the human male sexual response?

Although histamine has been suggested to be involved in the control of male sexual function, including the induction of penile erection, its role in the human corpus cavernosum penis is still poorly understood. The aim of our study was to evaluate the course of histamine plasma levels through different stages of sexual arousal in the systemic and cavernous blood of healthy male subjects. Thirty four (34) healthy men were exposed to erotic stimuli to elicit penile erection. Blood was aspirated from the corpus cavernosum and a cubital vein during the penile conditions flaccidity, tumescence, rigidity and detumescence. Blood was also collected in the post-ejaculatory period. Plasma levels of histamine (ng ml(-1)) were determined by means of a radioimmunoassay. Histamine slightly decreased in the cavernous blood when the penis became tumescent. During rigidity, histamine decreased further but remained unaltered in the phase of detumescence and after ejaculation. In the systemic circulation, no alterations were observed with the initiation or termination of penile erection, whereas a significant drop was registered following ejaculation. Results are not in favour of the hypothesis of an excitatory role of histamine in the control of penile erection. Nevertheless, the amine might mediate biological events during the post-ejaculatory period.

Independent NF1 and PTPN11 mutations in a family with neurofibromatosis-Noonan syndrome

Neurofibromatosis-Noonan syndrome (NFNS), an entity which combines both features of Noonan syndrome (NS) and neurofibromatosis type 1 (NF1), was etiologically unresolved until recent reports demonstrated NF1 mutations in the majority of patients with NFNS. The phenotypic overlap was explained by the involvement of the Ras pathway in both disorders, and, accordingly, clustering of the NF1 mutations in the GTPase-activating protein (GAP) domain of neurofibromin was observed in individuals with NFNS. We report on an 18-month-old girl with typical findings suggestive of NS in combination with multiple café-au-lait spots and bilateral optic gliomas suggestive of NF1. The patient was found to carry a de novo PTPN11 mutation p.T2I as well as the maternally inherited NF1 mutation c.4661+1G>C. Her otherwise healthy mother and brother, who also had the NF1 mutation, showed few café-au-lait spots as the only sign of neurofibromatosis. Since our patient's unique NF1 mutation results in skipping of exon 27a and thus involves the same region, Gap-related domain, that had been shown to be associated with NFNS, her phenotype could have been misleadingly attributed to the NF1 mutation only. Contrarily, absence of both cutaneous neurofibromas and NS features in her relatives with the same NF1 mutation, suggests that the index patient's typical NFNS phenotype is caused by an additive effect of mutations in both NF1 and PTPN11. In contrast to previous findings, we speculate that absence of cutaneous neurofibromas is not solely associated with the recurrent 3-bp in-frame deletion in exon 17.

Interlaboratory comparison of the determination of chlorinated dibenzo-p-dioxins and dibenzofurans according to regulatory methods EN 1948 and EPA 1613b

Four laboratories participated in a collaborative study to determine differences in analytical results generated according to two different compliance methods, US EPA Method 1613b and European Union Method EN 1948 for the determination of chlorinated dibenzo-p-dioxins and dibenzofurans (CDD/CDFs). Various sample matrices containing the analytes at levels ranging from parts-per-quadrillion (ppq) to parts-per-billion (ppb) were used to illustrate differences and similarities between the two analytical methods. The choice of the sample matrices analyzed in this study was made to mirror many of the real-world samples that are of interest to Dow and also to test the laboratories on many different, complex matrices. For this reason, commercially available performance evaluation samples were not used. The study results indicate that the 1613b requirement for confirmation of analyte identity and concentration on a second, polar gas chromatographic column for 2378-tetrachlorodibenzofuran (TCDF) only may lead to quantitative results which are biased high compared to EN 1948 which additionally requires confirmation for all 2378-substituted tetra--through hexachlorodibenzo-p-dioxins and dibenzofurans.

PCDD/Fs in ambient air collected in Zagreb, Croatia

Levels of PCDD/Fs were measured at four different sites in Zagreb, capital of Croatia. Also one sample was taken during spontaneously initiated open fire on a landfill and one sample where garden waste of unknown content was burnt. Over period 1997-2000, 28 samples were collected and levels ranged between 9 and 306 fgI-TEQm(-3), except in the sample collected during landfill fire. Air PCDD/F levels in Zagreb at four sites were different and the highest levels were observed in industrial area. Seasonal variation of levels is also evident with higher levels in winter than in summer. Our results show that PCDD/F levels in ambient air collected in Zagreb are at lower end of the published data range. In general, homologue profiles were quite similar for all locations, the concentration of PCDD homologues increased while the concentration of PCDF homologues decreased with increasing degree of chlorination. PCDD/F levels in the landfill fire sample was 13,200 fgI-TEQm(-3) which are much higher than levels in garden waste burning sample or in sample collected at industrial site. During landfill fire, the concentration of 2,3,7,8-TCDF becomes even higher than the concentration of OCDF and is equal to the concentration of 1,2,3,4,6,7,8-HpCDF.

Beta-cell function and islet morphology in normal, obese, and obese beta-cell mass-reduced Göttingen minipigs

Herein, we bridge beta-cell function and morphology in minipigs. We hypothesized that different aspects of beta-cell dysfunction are present in obesity and obesity with reduced beta-cell mass by using pulsatile insulin secretion as an early marker. Measures for beta-cell function (glucose and arginine stimulation plus baseline and glucose-entrained pulsatile insulin secretion) and islet morphology were studied in long-term (19-20 mo) obese (n = 5) and obese beta-cell-reduced [nicotinamide + streptozotocin (STZ), n = 5] minipigs and normal controls, representing different stages in the development toward type 2 diabetes. Acute insulin response (AIR) to glucose and arginine were, surprisingly, normal in obese (0.3 g/kg glucose: AIR = 246 +/- 119 vs. 255 +/- 61 pM in control; 67 mg/kg arginine: AIR = 230 +/- 124 vs. 214 +/- 85 pM in control) but reduced in obese-STZ animals (0.3 g/kg glucose: AIR = 22 +/- 36, P < 0.01; arginine: AIR = 87 +/- 92 pM, P < 0.05 vs. control). Baseline pulsatile insulin secretion was reduced in obese (59 +/- 16 vs. 76 +/- 16% in control, P < 0.05) and more so in obese-STZ animals (43 +/- 13%, P < 0.01), whereas regularity during entrainment was increased in obese animals (approximate entropy: 0.85 +/- 0.14 vs. 1.13 +/- 0.13 in control, P < 0.01). Beta-cell mass (mg/kg body wt) was normal in obese and reduced in obese-STZ animals, with pancreatic fat infiltration in both groups. In conclusion, obesity and insulin resistance are not linked with a general reduction of beta-cell function, but dynamics of insulin secretion are perturbed. The data suggest a sequence in the development of beta-cell dysfunction, with the three groups representing stages in the progression from normal physiology to diabetes, and assessment of pulsatility as the single most sensitive marker of beta-cell dysfunction.

Loss of beta-cell mass leads to a reduction of pulse mass with normal periodicity, regularity and entrainment of pulsatile insulin secretion in Göttingen minipigs

AIMS/HYPOTHESIS

Type 2 diabetes is associated with impaired insulin action and secretion, including disturbed pulsatile release. Impaired pulsatility has been related to impaired insulin action, thus providing a possible link between release and action of insulin. Furthermore, progressive loss of beta-cell mass has been implicated in the pathogenesis of Type 2 diabetes. The aim of this study was to evaluate a possible link between loss of beta-cell mass and impaired pulsatile insulin secretion with special focus on glucose responsiveness of insulin secretion.

METHODS

The kinetic and dynamic profiles of insulin in Göttingen minipigs are favourable for studies on pulsatility and a model of diabetes with reduced beta-cell mass has recently been established. Pigs were studied before (n=14) and after (n=10) reduction of beta-cell mass by nicotinamide (67 mg/kg) and streptozotocin (125 mg/kg) from 17.7+/-4.7 (normal animals, n=5) to 6.1+/-2.0 mg/kg. Pulsatile insulin secretion was examined during basal (n=8 normal, n=6 beta-cell reduced) and glucose entrained (n=6 normal, n=4 beta-cell reduced) conditions. Insulin concentration time series were analysed by autocorrelation and spectral analyses for periodicities and regularity, and by deconvolution for pulse frequency, mass and amplitude.

RESULTS

Reduction of beta-cell mass and secondary hyperglycaemia resulted in correspondingly (r=0.7421, p=0.0275) reduced pulse mass (42% of normal during basal and 31% during entrained conditions) with normal periodicity (6.6+/-2.2 vs 5.8+/-2.4 min, p=0.50), regularity and entrainability of insulin secretion.

CONCLUSION/INTERPRETATION

Neither beta-cell loss, nor 2 weeks of slight hyperglycaemia, as seen in the beta-cell-reduced minipig, probably accounts for the disturbed insulin pulsatility observed in human Type 2 diabetes.

The conscious Göttingen minipig as a model for studying rapid pulsatile insulin secretion in vivo

AIMS/HYPOTHESIS

Pulsatile secretion is important for insulin action and suitable animal models are important tools for examining the role of impaired pulsatile insulin secretion as a possible link between beta-cell mass, function and morphology and insulin resistance. This study examines the vascular sampling site, insulin kinetics, pulsatility and the response to glucose pulse entrainment to evaluate the Göttingen minipig as a model for studying pulsatile insulin secretion.

METHODS

Basal and glucose entrained insulin secretion was examined in normal minipigs and evaluated by autocorrelation, cross correlation and deconvolution.

RESULTS

Cross correlation showed a relation between oscillations in insulin concentrations in the portal and jugular vein in anaesthetised animals ( p<0.001 in all animals), confirming the usefulness of jugular vein sampling for pulse detection. Jugular vein sampling in conscious animals showed obvious oscillations allowing estimates of burst shape and insulin kinetics. Glucose entrainment improved the pulsatile pattern (autocorrelation: 0.555+/-0.148 entrained vs 0.350+/-0.197 basal, p=0.054). Deconvolution analysis resolved almost all insulin release as secretory bursts (69+/-20 basal vs 99.5+/-1.2% entrained, p<0.01) with a pulse interval (min) of 6.6+/-2.2 (basal) and 9.4+/-1.5 (entrained) ( p<0.05) and a pulse mass (pmol/l per pulse) which was higher after entrainment (228+/-117 vs 41.2+/-18.6 basal, p<0.001).

CONCLUSION/INTERPRETATION

The ability to fit kinetic parameters directly by deconvolution of peripheral endogenous insulin concentration time series in combination with the suitability of jugular vein sampling, rapid kinetics and entrainability makes the Göttingen minipig ideal for mechanistic studies of insulin pulsatility and its effects on insulin action.

On the architecture of high-latitude continental margins: the influence of ice-sheet and sea-ice processes in the Polar North Atlantic

The presence of ice during the Late Cenozoic distinguishes the nature and rates of processes on high-latitude margins from those elsewhere. Ice sheets terminating in marine waters deliver icebergs, meltwater and debris to high-latitude seas. Sea ice influences ocean salinity structure and downslope water and sediment transfer, and also transports fine-grained sediments over long distances. These cryospheric processes have led to the development of a distinctive sedimentary architecture on modern high-latitude continental margins. Large submarine fans made up almost entirely of stacked debris flows are present around the Norwegian-Greenland Sea. Large slides are located in a variety of settings relative to rates of sediment delivery from Quaternary ice-sheet margins, but no large slides have been mapped on the East Greenland margin. However, extensive channel systems and sediment-wave fields are present in the Greenland Basin, probably related to intermittent downslope flow of dense water and turbidity currents. The extensive NE Greenland shelf was not innundated by ice-sheet advance during recent full-glacial conditions, allowing sea-ice and deep-water production during both interglacials and full-glacials. Changes in the nature and rate of sedimentation within the Greenland Basin should provide clues on the rate of dense-water production, with implications for thermohaline circulation in the North Atlantic. Other erosional and depositional features on the Norwegian-Greenland Sea margins include canyons and contourite drifts. High-relief tectonic features influence sediment reworking by turbidity currents at abyssal depths. A simple conceptual model for glacier-influenced marine sedimentation summarizes the role of cryospheric processes in high-latitude margin sedimentary environments.

Combined PCDD/F destruction and particulate control in a baghouse: experience with a catalytic filter system at a medical waste incineration plant

Phoenix Services, Inc., owns and operates the Baltimore Regional Medical Waste Incinerator in Baltimore, MD. New regulations for dioxins and furans imposed a limit that was considerably below historical emission levels. To determine a method to comply with the new dioxin/furan regulations, Phoenix Services performed trials with powdered activated carbon (PAC). Although the results with carbon were acceptable, Phoenix Services decided to replace their woven fiberglass filter bags with catalytic filters that simultaneously destroy dioxins and furans and collect particulate matter (PM). The catalytic filter system offered several advantages to Phoenix Services, including destruction of dioxins and furans instead of adsorption on carbon. The catalytic filters also offered a passive solution that did not require new carbon injection equipment. In January 2000, a campaign to measure dioxins/furans and PM was undertaken. The measurements allowed the catalytic filter system to be evaluated. Some of the key findings of this investigation are The dioxin/furan emission was less than 0.1 ng toxicity equivalents (TEQ)/Nm3 at 11% O2. This concentration is approximately 2 orders of magnitude less than historical averages and it is well below the new regulatory limits, for both existing and new sources of this type; the amount of dioxin/furans destroyed by the catalytic filters was approximately 1.73 ng TEQ/Nm3 at 11% O2; and the particulate emission was 12-17 times less than the regulatory limit.

Parameters of glucose and lipid metabolism in the male Göttingen minipig: influence of age, body weight, and breeding family

The pig is useful as a model for human physiology and pathophysiology and could be an important supplement to the many available rodent models of diabetes mellitus. Due to their small size, Göttingen minipigs are especially suitable for long-term studies. The aim of the study reported here was to establish reference values for a range of glucose and lipid homeostasis parameters of interest that could be used to identify possible diabetes-prone male Göttingen minipig individuals, families, or age groups. Plasma samples from nonfed animals were analyzed for glucose, leptin, fructosamine, insulin, C-peptide, triglyceride, free fatty acids, and total cholesterol values. Breeding family had significant effects only on plasma triglyceride concentrations (P < 0.001). Plasma concentrations of glucose (P = 0.012), fructosamine (P < 0.001) and triglycerides (P < 0.001) increased significantly with age, whereas total cholesterol concentration decreased significantly (P = 0.001) with age. Age did not influence other parameters. In conclusion, glycemia and insulinemia increased with age and body weight, possibly indicating a small deterioration in insulin sensitivity with age. It is, therefore, hypothesized that older, compared to younger animals may be more useful in the development of a model of type-2 diabetes mellitus. Furthermore, on the basis of decrease in cholesterol concentration with age, animals fed ad libitum with possibly a high calorie diet might be even more useful in the development of a type-2 diabetes mellitus model.

Comparison of methods of analysis of body composition in hypophysectomized rats treated with rat growth hormone

The present study compared estimates of body composition derived from dual-emission X-ray absorptiometry (DEXA) and from chemical analyses. The primary aim was to compare the two methods because growth hormone (GH) may cause fluid retention, and DEXA does not distinguish water from lean mass. Hypophysectomized rats were fed ad libitum and were treated with continuous infusions of rat GH in doses of 0, 10, 30, and 100 microg/day for 14 days. By chemical analysis, a decrease in percentage fat from 12.9% in the control group to 11.3%, 11.0%, and 10.2% in the low, medium, and high dose groups was observed (P < 0.0001). The fat percentages were about 3-4% higher by DEXA, but showed the same decline (P < 0.03). Lean mass increased from 74.4% in the control group to 75.8%, 78.0%, and 78.6% in the treatment groups (P < 0.001). A significant increase in the wet weight of the quadriceps muscle, but no difference in dry weight was observed in all four treatment groups, indicating that the increase in muscle weight was exclusively caused by water. This accumulation of water was reflected in the total water content of the carcasses, which increased from 62.0% in the control group to 64.9%, 66.1%, and 66.8% in the GH groups (P < 0.0001). The protein content decreased from 19.8% in the control group to 19.4%, 19.1%, and 18.9% in the GH groups (P < 0.001). Regardless of the decrease in protein, the GH treated groups contained more water in relation to protein as the g water/g protein ratio was increased by 13% from 3.14 in the control group to 3.55 in the group treated with the highest GH dose (P < 0.0001). Also, a close relationship between feed intake and body weight were found, together with increases in epiphyseal growth plate width, insulin-like growth factor I (IGF-I), and insulin-like growth factor binding protein 3 (IGFBP-3). In conclusion, the study shows that estimation of lean mass by DEXA should be carefully evaluated when used in connection with treatment of drugs that cause water retention.

Potent derivatives of glucagon-like peptide-1 with pharmacokinetic properties suitable for once daily administration

A series of very potent derivatives of the 30-amino acid peptide hormone glucagon-like peptide-1 (GLP-1) is described. The compounds were all derivatized with fatty acids in order to protract their action by facilitating binding to serum albumin. GLP-1 had a potency (EC(50)) of 55 pM for the cloned human GLP-1 receptor. Many of the compounds had similar or even higher potencies, despite quite large substituents. All compounds derivatized with fatty acids equal to or longer than 12 carbon atoms were very protracted compared to GLP-1 and thus seem suitable for once daily administration to type 2 diabetic patients. A structure-activity relationship was obtained. GLP-1 could be derivatized with linear fatty acids up to the length of 16 carbon atoms, sometimes longer, almost anywhere in the C-terminal part without considerable loss of potency. Derivatization with two fatty acid substituents led to a considerable loss of potency. A structure-activity relationship on derivatization of specific amino acids generally was obtained. It was found that the longer the fatty acid, the more potency was lost. Simultaneous modification of the N-terminus (in order to obtain better metabolic stability) interfered with fatty acid derivatization and led to loss of potency.

Methylprednisolone does not inhibit the release of growth hormone after intravenous injection of a novel growth hormone secretagogue in rats

The present study was undertaken to study the growth hormone-releasing properties and growth-promoting effect of a GH secretagogue ipamorelin (IPA) in rats given the synthetic glucocorticoid methylprednisolone (MP). In a first experiment, rats received either saline or MP (5.0 mg/kg) for 8 days. Treatment with MP significantly (P< 0.001) decreased body weight gain, but the acute response to either IPA or growth hormone releasing hormone (GHRH) in terms of plasma GH was not changed. In a second experiment, venous catheters were surgically implanted. On the next day, rats were randomly allocated to receive saline alone, MP alone (5.0 mg/kg) or MP plus IPA in doses of 0.4 or 1.6 mg/kg/day for 10 days. IPA was administered intravenously four times a day.MP treatment significantly (P< 0.05) retarded recovery from surgery in terms of body weight. Thus, saline treated animals lost 4.0 +/- 3.5 g over the entire experimental period, whereas animals receiving MP lost 13. 6 +/- 2.9 g. When IPA was given together with MP, losses in body weight were significantly (P< 0.05) reduced to 2.3 +/- 2.0 and 1.6 +/- 2.0 g in animals given the high and low dose of IPA, respectively. In parallel with this IGF-I levels increased. In conclusion, this work shows that MP does not disrupt the response of the GH-IGF-I axis to an exogenous stimulus like IPA, and repeated stimulation leads to increases in IGF-I and of body weight gain.

Ipamorelin, a new growth-hormone-releasing peptide, induces longitudinal bone growth in rats

Ipamorelin is a new and potent synthetic pentapeptide which has distinct and specific growth hormone (GH)-releasing properties. With the objective of investigating the effects on longitudinal bone growth rate (LGR), body weight (BW), and GH release, ipamorelin in different doses (0, 18, 90 and 450 microg/day) was injected s.c. three times daily for 15 days to adult female rats. After intravital tetracycline labelling on days 0, 6, and 13, LGR was determined by measuring the distance between the respective fluorescent bands in the proximal tibia metaphysis. Ipamorelin dose-dependently increased LGR from 42 microm/day in the vehicle group to 44, 50, and 52 microm/day in the treatment groups (P<0.0001). There was also a pronounced and dose-dependent effect on BW gain. The treatment did not affect total IGF-I levels, IGFBPs, or serum markers of bone formation and resorption. The number of tartrate-resistant acid phosphatase-positive multinuclear cells in the metaphysis of the tibia did not change significantly with treatment. The responsiveness of the pituitary to a provocative i.v. dose of ipamorelin or GHRH showed that the plasma GH response was marginally reduced (P<0.03) after ipamorelin, but unchanged after GHRH. The pituitary GH content was unchanged by ipamorelin treatment. Whether ipamorelin or other GH secretagogues may have a place in the treatment of children with growth retardation requires demonstration in future clinical studies.

A novel inhibitor of advanced glycation end-product formation inhibits mesenteric vascular hypertrophy in experimental diabetes

AIMS/HYPOTHESIS

Previous studies in our laboratory have shown that the vascular changes in diabetes include hypertrophy of the mesenteric vasculature and that this process can be attenuated by the inhibition of advanced glycation with aminoguanidine. Since aminoguanidine can also act as an inhibitor of nitric oxide synthase, the effect of a novel inhibitor of advanced glycation end-products, formation that does not inhibit nitric oxide synthase, known as 2,3 diaminophenazine (2,3 DAP) was evaluated.

METHODS

Initially, in vitro assessment of the ability of 2,3 diaminophenazine to inhibit formation of advanced glycation products was performed. Subsequently, in vivo studies evaluating 2,3 diaminophenazine and aminoguanidine were carried out. Animals were followed for 3 weeks after induction of diabetes and randomised to no treatment, aminoguanidine or 2,3 diaminophenazine. Mesenteric vessels were weighed and advanced glycation end-products were measured by radioimmunoassay in vessel and kidney homogenates. In addition, these products were assessed in mesenteric vessels by immunohistochemistry.

RESULTS

When compared with control animals, diabetes was associated with an increase in mesenteric vascular weight. Treatment of diabetic rats with aminoguanidine or 2,3 diaminophenazine resulted in attenuation of vascular hypertrophy. Both aminoguanidine and 2,3 diaminophenazine reduced the formation of advanced glycation end-products as measured by radioimmunoassay and as assessed immunohistochemically in these vessels. This reduction was also observed in the kidney.

CONCLUSION/INTERPRETATION

These data support the concept that the effects of aminoguanidine in reducing diabetes associated vascular hypertrophy are via inhibition of advanced glycation end-products dependent pathways.

Suppression of mycelia formation by NO produced endogenously in Candida tropicalis

In the experiments reported here we found that enzymatic NO synthesis in the yeast Candida tropicalis resembles the one in animal tissues with respect to the substrate arginine as well as its sensitivity to potential competitive inhibitors. Both, NO produced by the yeast's nitric oxide synthase and NO derived from an artificial donor, suppressed the formation of pseudomycelia. These results suggest to make use of NO as a tool in elucidating the mechanism controlling mycelia generation in this yeast. The apparent K(m) towards oxygen of the yeast's nitric oxide synthase (about 50 microM) was found to be high as compared to the apparent K(m) value of the yeast's respiratory chain (about 170 nM). From this observation it may be concluded that under conditions of little oxygen supply the nitric oxide synthase will unsuccessfully compete for oxygen with respiration. Therefore, the formation of mycelia spontaneously occurring in yeast cultures grown in sealed chambers can be attributed to a reduced internal NO level rather than limited respiratory activity.

Plasma concentration of hGH and anti-hGH antibodies after subcutaneous administration of hGH for 3 weeks to immunosuppressed pigs

OBJECTIVE

The objective of the present study was to evaluate the dosing regimen of immunosuppressants necessary to avoid the formation of anti-hGH antibodies in a pig model.

ANIMALS

Sixteen pigs were divided into four groups.

PROCEDURE

Three different immunosuppressive treatments were tested (group 1: Control (no treatment); group 2: 10 mg; group 3: 20 mg; and group 4: 40 mg cyclosporine; combined with 2 mg azatioprine and 2 mg prednisolone p.o./kg/day). The treatments were given from days -7 to 22. All groups were dosed subcutaneously (s.c.) with 0.5 mg hGH/kg once daily from days 1 to 22. On the first and the last days of dosing blood samples were collected to describe the hGH concentration versus time profile. Before dosing and on days 5, 10, and 15 blood samples were collected for measuring hGH antibody formation.

RESULTS

A dose-dependent decrease in white blood cell counts was observed in all immunosuppressive-treated groups. Groups 1 and 2 produced antibodies against hGH during the 22 days of dosing while the formation of antibodies was suppressed in groups 3 and 4. In the control group and group 2 the pharmacokinetic parameters of hGH were influenced by the formation of anti-hGH antibodies. In groups 3 and 4, the pharmacokinetic parameters were comparable on the first and the last day of dosing.

CONCLUSION

The formation of anti-hGH antibodies influenced the pharmacokinetics of hGH in pigs, but it could be prevented by immunosuppressive therapy. From the present experiment, a dose of 20 mg cyclosporine, 2 mg azatioprine, and 2 mg prednisolone p.o./kg/day was able to prevent the pigs from producing antibodies without having severe adverse effects. This model may by useful in future experiments using sustained release formulations of hGH, and possibly for other compounds that may induce antibody production in pigs.

State regulatory board structure, regulations, and nurse practitioner availability

State boards of nursing (BON) and medicine (BOM) promulgate regulations that affect nurse practitioners (NPs). Certain characteristics of board structure have an impact on two potential barriers to NP practice: the absence of direct third-party reimbursement and authority to prescribe. The percentage of consumers on BONs and BOMs increases the likelihood of direct third-party reimbursement for NPs. The presence of an NP committee providing input to a board increases the likelihood of authority to prescribe for NPs. The availability of NPs is enhanced by the presence of NP educational programs in the state, the level of effort by the state related to NP recruitment and retention, and the presence of direct third-party reimbursement.

Atrial baffle procedures for complete transposition of the great arteries: natural course of sinus node dysfunction and risk factors for dysrhythmias and sudden death

359 patients after the Mustard (275) or Senning (84) operations for transposition of the great arteries were followed-up for a mean of 103.7 (range 0.4 to 204) months. 259 patients had postoperative 24-h Holter recordings. In 129 Mustard children serial (mean 4.4) postoperative Holter recordings were available for evaluation. Criteria based on Holter and scalar electrocardiograms at normal sinus node functions were used for rhythm analysis. Postoperative dysrhythmias appeared in 70% of the patients: sinus node dysfunction in 62.8%, second or third degree atrioventricular block in 3.2%, sustained atrial tachycardia or atrial flutter in 4.5%, and significant ventricular arrhythmia (Lown 2-5) in 21.4%. The prevalence of sinus node dysfunction increased slightly from 50.8% during the first 2 postoperative years to 64.4% in patients more than 10 years postoperatively. Fifteen patients (4.2%) died suddenly during follow-up. By multivariate analysis severe tricuspid regurgitation and/or right ventricular dysfunction and uncontrolled supraventricular tachydysrhythmias were identified as the two significant risk factors for sudden death.

Continuous arteriovenous haemofiltration in critically ill children

We report 24 children with acute renal failure treated with continuous arteriovenous haemofiltration (CAVH) between 1987 and 1991. The median age was 2.9 years (range 3 days to 9 years). The main causes of the acute renal failure were: open heart surgery (n = 11) and liver failure of different origins before and after liver transplantation (n = 10). The indication for CAVH was oliguria or fluid overload in all children. The femoral vessels were used as vascular access in most instances. Different filters were used, depending on the size of the patient and an average ultrafiltration of 130 +/- 89 ml/h was achieved, which resulted in a fluid clearance of 4.0 +/- 2.6 ml/min per 1.73 m2. In 18 patients uraemia was adequately controlled. Nine children survived after recovery of their renal function; 15 (62.5%) died as a consequence of multiorgan failure. We conclude that CAVH is an effective method to support critically ill children with acute renal failure.

[Menstrual toxic shock syndrome]

A 15 year old girl presented twice with severe symptoms of multiorgan disease during a period of 4 weeks resulting in intensive care necessary to control illness. According to case definition criteria, a toxic shock syndrome was diagnosed on second admission. This could be confirmed by proof of TSST-1. Beside antibiotics, no specific treatment was used and complete clinical recovery occurred with symptomatic therapy. Discussing the menstrual toxic shock syndrome we point out different aspects of the pathogenesis of the disease including the possible role of tampon use. With regard to the results of several investigators, clinical symptoms of toxic shock syndrome could be the consequence of an uncontrolled immunologic reaction. Looking at this concept, more effective therapy may be available in the near future.

[Emergency 12-hour transesophageal stimulation in a 21-month-old infant]

In a 21-month-old child with complex cyanotic congenital heart disease an aortopulmonary shunt was created as preparation for a modified Fontan operation. During the early postoperative period low cardiac output with right atrial pressures of 20 mm Hg developed due to a slow ventricular tachycardia (ventricular rate 135 bpm). Pharmacological interventions (isoprenaline 0.01 mg/kg hourly and lidocaine 1 mg/kg hourly were without any effect. As epicardial pacing leads had not been implanted during surgery, atrial pacing was performed via the transoesophageal route using a 9.5-F bipolar electrode catheter with an interelectrode distance of 15 mm. Atrial capture could be established with an impulse width of 9.9 ms and 10 mA output at a rate of 150 bpm. With restoration of atrioventricular synchronicity, right atrial pressure finally decreased to 10 mm Hg with consecutive stabilization of the cardiovascular status. After 12.5 h transoesophageal pacing could be stopped without any problems due to spontaneous cessation of ventricular tachycardia. No clinical signs of oesophageal injury were noted. It is concluded that transoesophageal pacing is a practical, safe and effective method for emergency cardiac pacing.

[Value of thrombolytic therapy in childhood]

Indications for fibrinolytic therapy in infants and young children differ significantly from those in adults. In preterm and newborn infants, it is mostly the catheter-associated thrombosis following catheterisation of the umbilical artery or vein that requires fibrinolytic therapy. In young children the main indication is arterial thrombosis after cardiac catheterisation. Based on the current literature and our own experience guidelines as well as recommendations for dosages are given for systemic and local therapy with streptokinase, urokinase and recombinant tissue plasminogen activator.

[Therapy of postoperative ectopic junctional tachycardia by surface hypothermia]

Postoperative junctional ectopic tachycardia is associated with a poor prognosis in patients after open-heart surgery. This dysrhythmia has been shown to be resistant to medical treatment as well as to epicardial pacing and external cardioversion. Successful therapy with surface hypothermia in an infant with junctional ectopic tachycardia (ventricular rate 210-230 bpm) after repair of tetralogy of Fallot is presented. Hypothermia (rectal temperature 32-34 degrees C) was effective in decreasing the ventricular rate of the dysrhythmia (< 170 bpm). After spontaneous cessation of the tachycardia, sinus rhythm resumed, resulting in stable hemodynamics.

[Accuracy of measurements of Kontrol 7840, Nellcor N200 and Radiometer OX13 pulse oximeters in infants and young children]

Comparative validation studies of pulse oximeters from different manufacturers have predominantly been performed in adult patients. However, due to differences in the patient-sensor interface, the results from those studies may not be transferable to the paediatric population. We therefore performed 123 simultaneous measurements (37 patients) of transcutaneous O2-saturation (StcO2) from 3 pulse oximeters and compared these with the arterial O2-saturation (SaO2) from a co-oximeter (Radiometer OSM 3). The median age of the 37 patients at the time of study was 2.0 months (range 1 day-5 years), their weight 4.7 kg (0.8-15.0 kg). The mean difference between StcO2 and SaO2 was -0.6% (SD 5.2%) for the Kontron 7840 pulse oximeter, -0.9% (SD 2.3%) for the Nellcor N200, and -1.2% (SD 3.5%) for the Radiometer OXI3 pulse oximeter. The corresponding 95% intervals were -7.4(-) + 9.6%, -5.7(-) + 4.3% and -7.0(-) + 6.3% for the Kontron, Nellcor and Radiometer instrument, respectively. These results demonstrate that neither of the 3 instruments systematically under- or overestimated SaO2. However, there were differences in precision, particularly in the low range of SaO2.

Reliability of a pulse oximeter in the detection of hyperoxemia

To evaluate the reliability of the Nellcor N200 pulse oximeter in the detection of hyperoxemia (oxygen tension > 80 mm Hg), we obtained 213 simultaneous recordings and measurements of transcutaneous oxygen saturation (SO2) and arterial oxygen tension (PaO2) in 50 patients. During 95% of measurements with PaO2 > 80 mm Hg, SO2 was > or = 96%; SO2 was also > or = 96% in 20% of measurements with PaO2 < or = 80 mm Hg (false-positive results for hyperoxemia). With the upper alarm limit set at 95%, the pulse oximeter identified 95% of hyperoxemic instances while allowing PaO2 to be kept to > 60 mm Hg.

Pulmonary artery sling with tracheal stenosis: primary one-stage repair in infancy

Pulmonary artery sling is often associated with tracheal stenosis. In many cases repair of the vascular anomaly alone does not relieve dyspnea. Primary one-stage repair with long segment tracheal resection (2.4 cm) and relocation of the left pulmonary artery using cardiopulmonary bypass and deep hypothermic circulatory arrest is described in a 6.5-month-old girl weighing 6.5 kg. This technique resulted in normal ventilation and pulmonary flow distribution.

[Thrombotic occlusion of the abdominal aorta in the neonatal period--successful thrombolytic treatment]

Aortic thrombosis during neonatal period is rare and usually related to an umbilical artery catheter. In an infant (birth weight 3110 gm) with complete thrombosis of the abdominal aorta distal to the renal arteries of unknown etiology we started a fibrinolytic therapy with streptokinase at the age of 12 days (streptokinase intravenously with an initial loading dose of 3000 U/kg, maintenance 1000 U/kg/hr for 2 days). This was followed by a heparinisation (10,000 U/m2/d, 24 hours later 200 U/kg/d). 72 hours after onset of therapy there was no blood pressure difference between upper and lower limbs. Side-effects of therapy did not occur; the success of medical treatment continued after termination of the heparinisation.

[Complex cyanotic heart defect in a newborn infant with cat eye syndrome]

In a cyanotic newborn with characteristic features of Cat-Eye-Syndrome, cytogenetic examination disclosed a supernumerary small bisatellited chromosome. Angiography showed Tetralogy of Fallot with pulmonary atresia and a narrow patent ductus arteriosus with additional stenosis of the bifurcation of the pulmonary artery. At an age of 14 weeks, the patient died after the attempt of corrective cardiac surgery. Congenital cardiac malformation is present in more than one third of patients with cat-eye-syndrome and is usually the lifelimiting malformation in this syndrome.

The DiGeorge syndrome. I. Clinical evaluation and course of partial and complete forms of the syndrome

This study describes clinical signs and symptoms in 16 patients with the DiGeorge syndrome (DGS). Diagnosed on the basis of typical facial stigmata, a broad spectrum of severity is seen with respect to congenital heart disease, hypoparathyroidism and immunologic parameters. A simple index of severity is introduced that clearly differentiates complete forms of the syndrome (cDGS) with poor prognosis from partial forms of the syndrome (pDGS). Of 13 pDGS patients, 12 are still living; 8 underwent corrective heart surgery without infectious complications. Moderate to severe mental retardation is seen in all pDGS patients. Due to the lack of thymus function, immunodeficiency is a result of cDGS, whereas immunoregulatory disturbances (hypergammaglobulinaemia, high titres of specific antibody production) prevail in pDGS patients.

Modification of beta-2-microglobulin in sera from patients with small cell lung cancer: evidence for involvement of a serine protease

Modification of beta-2-microglobulin has been shown to occur in vitro in serum of patients suffering of small cell lung cancer, where it clearly correlated to the clinical course of disease. The cause of serum beta-2-microglobulin modification occurring in these patients is investigated in the present study. This revealed that modification of beta-2-microglobulin is due to cleavage by a serine protease, which is dependent on divalent cations and has a trypsin-like specificity. The process showed the following characteristics: pH optimum at 8.5, heat inactivation by incubation at 56 degrees C for 20 min and temperature optimum at 20 degrees C.

Expression of an antigen defined by a monoclonal antibody (SA-1) on normal and malignant cells

A monoclonal antibody (SA-1) has been characterized. The antibody was derived from the fusion of the X-63 myeloma cell-line with splenocytes from a mouse immunized with human acute megakaryoblastic leukaemia cells. The antibody reacted with blast cells from 65% of patients with AML without correlation to morphologic classification. The antibody further reacted with a subset of myeloid cells from normal bone marrow, and with peripheral neutrophil granulocytes. In lymph nodes the antibody showed reactivity with subsets of dendritic reticulum cells. In skin biopsies the antibody reacted with subsets of Langerhans cells, subsets of indeterminate cells and activated T-lymphocytes. The antigen was not expressed on non-activated T-lymphocytes. Neither was it expressed on B-lymphocytes, erythrocytes, platelets nor blast cells from patients with ALL. The antigenic target for the antibody SA-1 was a surface exposed polypeptide (mol. wt. 15 000 D).

Reliability of the Hitachi sodium and potassium electrodes assessed

We compared the Hitachi 705 E sodium/potassium electrode system with the Radiometer flame photometer for measuring concentrations of sodium and potassium ions in serum and plasma. Our data show that the Hitachi results are slightly but significantly (less than 0.001) lower than the flame photometer results: Na+ 1.33 mmol/L for serum and 2.24 mmol/L for plasma; K+ 0.062 mmol/L for serum and 0.082 mmol/L for plasma. The magnitude of the bias varied considerably from day to day, ranging from -0.10 to 2.33 mmol/L for Na+ in serum and from 0.00 to 0.11 mmol/L for serum K+; for plasma specimens the corresponding ranges were -0.03 to 5.97 mmol/L and 0.00 to 0.17 mmol/L. These variations probably reflected difficulties in reproducing the calibration from day to day, because the daily means for a serum pool varied in parallel. We occasionally encountered serious problems with reproducibility.

Reliability of the Hitachi sodium and potassium electrodes assessed

We compared the Hitachi 705 E sodium/potassium electrode system with the Radiometer flame photometer for measuring concentrations of sodium and potassium ions in serum and plasma. Our data show that the Hitachi results are slightly but significantly (less than 0.001) lower than the flame photometer results: Na+ 1.33 mmol/L for serum and 2.24 mmol/L for plasma; K+ 0.062 mmol/L for serum and 0.082 mmol/L for plasma. The magnitude of the bias varied considerably from day to day, ranging from -0.10 to 2.33 mmol/L for Na+ in serum and from 0.00 to 0.11 mmol/L for serum K+; for plasma specimens the corresponding ranges were -0.03 to 5.97 mmol/L and 0.00 to 0.17 mmol/L. These variations probably reflected difficulties in reproducing the calibration from day to day, because the daily means for a serum pool varied in parallel. We occasionally encountered serious problems with reproducibility.

Demonstration and partial characterization of chronic lymphocytic leukemia lymphocyte-associated antigens by crossed immunoelectrophoresis of Triton X-100 extracts

Crossed immunoelectrophoresis was used to study the antigens of chronic lymphocytic leukemia lymphocytes. A reference pattern was obtained and 20 samples from 18 patients were compared with this pattern. Extensive variation in the expression of individual antigens was observed. The antigens in the reference pattern were further characterized by modifications of crossed immunoelectrophoresis, viz. labelling of intact lymphocytes by lactoperoxidase-catalyzed iodination, affinity crossed immunoelectrophoresis with phenyl-Sepharose and Lentil lectin-Sepharose, charge-shift crossed immunoelectrophoresis and postelectrophoretic incubation in (125I) Lentil lectin. Six antigens were identified as surface membrane glycoproteins, 5 as cytoplasmic proteins while 5 could not be classified. Two antigens were finally identified as HLA-ABC and HLA-DR by application of small amounts of monospecific rabbit antiserum and monoclonal antibody, respectively.

Monoclonal immunoglobulin of CLL lymphocytes detected by radioimmunofixation with 125I-protein A of Triton X-100 solubilized lymphocyte material

A sensitive radioimmunofixation method (detection limit 1 mg/1 for monoclonal IgM) utilizing 125I Protein A and immunofixation for demonstration of monoclonal immunoglobulin in Triton X-100 extracts of isolated chronic lymphocytic leukemia (CLL) lymphocytes is presented. Thirty-two untreated patients with clinically typical CLL were studied and the results compared to those obtained by immunofluorescence. Monoclonal IgM was detected with similar frequency by the two methods (69% and 75%), but IgD was detected less frequently by radioimmunofixation (25% and 40%). When the results obtained with the two methods were combined, all of the cases were immunoglobulin positive. Two complete IgM type M-components were demonstrated in two cases, an excess of seemingly free heavy chains was found in four cases, and an excess of seemingly free light chains in six cases.