Mortality in Chicago attributed to the July 1995 heat wave

OBJECTIVES

This study assessed mortality associated with the mid-July 1995 heat wave in Chicago.

METHODS

Analyses focused on heat-related deaths, as designated by the medical examiner, and on the number of excess deaths.

RESULTS

In July 1995, there were 514 heat-related deaths and 696 excess deaths. People 65 years of age or older were overrepresented and Hispanic people underrepresented. During the most intense heat (July 14 through 20), there were 485 heat-related deaths and 739 excess deaths.

CONCLUSIONS

The methods used here provide insight into the great impact of the Chicago heat wave on selected populations, but the lack of methodological standards makes comparisons across geographical areas problematic.

Ultrasensitive and fast bottom-up analysis of femtogram amounts of complex proteome digests

Femtogram proteomics: An ultrasensitive capillary zone electrophoresis-mass spectrometry system that is based on an improved nanospray interface has been developed. This system is used for the analysis of picogram to femtogram amounts of E. coli digests; for example, over 100 proteins were identified from 16 pg digests by tandem mass spectrometry. AMTs=accurate mass and time tags.

Third-generation electrokinetically pumped sheath-flow nanospray interface with improved stability and sensitivity for automated capillary zone electrophoresis-mass spectrometry analysis of complex proteome digests

We have reported a set of electrokinetically pumped sheath flow nanoelectrospray interfaces to couple capillary zone electrophoresis with mass spectrometry. A separation capillary is threaded through a cross into a glass emitter. A side arm provides fluidic contact with a sheath buffer reservoir that is connected to a power supply. The potential applied to the sheath buffer drives electro-osmosis in the emitter to pump the sheath fluid at nanoliter per minute rates. Our first-generation interface placed a flat-tipped capillary in the emitter. Sensitivity was inversely related to orifice size and to the distance from the capillary tip to the emitter orifice. A second-generation interface used a capillary with an etched tip that allowed the capillary exit to approach within a few hundred micrometers of the emitter orifice, resulting in a significant increase in sensitivity. In both the first- and second-generation interfaces, the emitter diameter was typically 8 μm; these narrow orifices were susceptible to plugging and tended to have limited lifetime. We now report a third-generation interface that employs a larger diameter emitter orifice with very short distance between the capillary tip and the emitter orifice. This modified interface is much more robust and produces much longer lifetime than our previous designs with no loss in sensitivity. We evaluated the third-generation interface for a 5000 min (127 runs, 3.5 days) repetitive analysis of bovine serum albumin digest using an uncoated capillary. We observed a 10% relative standard deviation in peak area, an average of 160,000 theoretical plates, and very low carry-over (much less than 1%). We employed a linear-polyacrylamide (LPA)-coated capillary for single-shot, bottom-up proteomic analysis of 300 ng of Xenopus laevis fertilized egg proteome digest and identified 1249 protein groups and 4038 peptides in a 110 min separation using an LTQ-Orbitrap Velos mass spectrometer; peak capacity was ∼330. The proteome data set using this third-generation interface-based CZE-MS/MS is similar in size to that generated using a commercial ultraperformance liquid chromatographic analysis of the same sample with the same mass spectrometer and similar analysis time.

Lyn associates with the juxtamembrane region of c-Kit and is activated by stem cell factor in hematopoietic cell lines and normal progenitor cells

Stem cell factor (SCF) is a cytokine critical for normal hematopoiesis. The receptor for SCF is c-Kit, a receptor tyrosine kinase. Our laboratory is interested in delineating critical components of the SCF signal transduction pathway in hematopoietic tissue. The present study examines activation of Src family members in response to SCF. Stimulation of cell lines as well as normal progenitor cells with SCF rapidly increased tyrosine phosphorylation of the Src family member Lyn. Peak responses were noted 10-20 min after SCF treatment, and phosphorylation of Lyn returned to basal levels 60-90 min after stimulation. SCF also induced increases in Lyn kinase activity in vitro. Lyn coimmunoprecipitated with c-Kit, and studies with GST fusion proteins demonstrated that Lyn readily associated with the juxtamembrane region of c-Kit. Treatment of cells with either Lyn antisense oligonucleotides or PP1, a Src family inhibitor, resulted in dramatic inhibition of SCF-induced proliferation. These data demonstrate that SCF rapidly activates Lyn and suggest that Lyn is critical in SCF-induced proliferation in hematopoietic cells.

IL-7 administration alters the CD4:CD8 ratio, increases T cell numbers, and increases T cell function in the absence of activation

IL-7 is vital for the development of the immune system and profoundly enhances the function of mature T cells. Chronic administration of IL-7 to mice markedly increases T cell numbers, especially CD8(+) T cells, and enhances T cell functional potential. However, the mechanism by which these effects occur remains unclear. This report demonstrates that only 2 days of IL-7 treatment is needed for maximal enhancement of T cell function, as measured by proliferation, with a 6- to 12-fold increase in the proportion of CD4(+) and CD8(+) T cells in cell cycle by 18 h of ex vivo stimulation. Moreover, a 2-day administration of IL-7 in vivo increases basal proliferation by 4- and 14-fold in CD4(+) and CD8(+) T cells, respectively. These effects occur in the absence of cytokine production, increases in most activation markers, and changes in memory markers. This enhanced basal proliferation is the basis for the increase in T cell numbers in that IL-7 induces an additional 60% and 85% of resting CD4(+) and CD8(+) T cells, respectively, to enter cell cycle in mice given IL-7 for 7 days. These results demonstrate that in vivo administration of IL-7 increases T cell numbers and functional potential via a homeostatic, nonactivating process. These findings may suggest a unique clinical niche for IL-7 in that IL-7 therapy may increase T cell numbers and enhance responses to specific antigenic targets while avoiding a general, nonspecific activation of the T cell population.

Stat1 associates with c-kit and is activated in response to stem cell factor

Interaction of stem cell factor (SCF), a haematopoietic growth factor, with the receptor tyrosine kinase c-kit leads to autophosphorylation of c-kit as well as tyrosine phosphorylation of various substrates. Little is known about the role of the JAK/STAT pathway in signal transduction via receptor tyrosine kinases, although this pathway has been well characterized in cytokine receptor signal transduction. We recently found that the Janus kinase Jak2 associates with c-kit and that SCF induces rapid and transient phosphorylation of Jak2. Here we present evidence that SCF activates the transcription factor Stat1. Phosphorylated c-kit co-immunoprecipitates with Stat1 within 1 min of SCF stimulation of the human cell line MO7e. Co-precipitation experiments using glutathione S-transferase fusion proteins indicate that association with c-kit is mediated by the Stat1 SH2 domain. Stat1 is rapidly tyrosine-phosphorylated in response to SCF in MO7e cells, the murine cell line FDCP-1 and normal progenitor cells. SCF-induced phosphorylation of Jak2 and Stat1 was also observed in murine 3T3 fibroblasts stably transfected with full-length human c-kit receptor. Furthermore c-kit directly phosphorylates Stat1 fusion proteins in in vitro kinase assays. Electrophoretic mobility-shift assays with nuclear extracts from SCF-stimulated cell lines and normal progenitor cells indicate that activated Stat1 binds the m67 oligonucleotide, a high-affinity SIE promoter sequence. These results demonstrate that Stat1 is activated in response to SCF, and suggest that Stat1 is a component of the SCF signal-transduction pathway.

Preparation and blood compatibility of polysiloxane/liquid-crystal composite membranes

Polysiloxane/liquid crystal composite membrane was first suggested to be used as biomaterials. In this work, the polydimethyl-methylhydrosiloxane and polydimethyl-methylethylenesilosiane, as a substrate, were blended with cholesteryl oleyl carbonate (COC) in tetrahydrofuran, and then crosslinked into membranes on glass plates by means of the platinum catalyst at 110 degrees C for 20 min. The effects of the liquid-crystal content in composite membranes on the formation of liquid-crystal phase were verified by the observation of optical polarization microscopy. The relationship between the morphology of the composite membranes and blood compatibility was identified by the dynamic blood-clotting tests, haemolysis ratio measurement, platelet adhesion and SEM observation. The results show that the blood-compatibility of composite membranes with the concentration of liquid crystal 20, 30% (wt) is more excellent than that of other composite membranes.

A new strategy to replace the natural vitreous by a novel capsular artificial vitreous body with pressure-control valve

PURPOSE

The current vitreous substitutes such as silicone oil, heavy silicone oil, and polymeric gels that are directly injected into vitreous cavity frequently cause severe intraocular complications. There is a very urgent need to find a more suitable artificial vitreous substitute for pars plana vitrectomy (PPV) surgery.

METHODS

We have devised a novel capsular artificial vitreous using tailor-made silicone rubber elastomer. The novel device was implanted into the vitreous cavity of rabbit after PPV and the eye was examined by ophthalmoscopy, fundus photography, and tonometry during an 8-week treatment period. B-scan ultrasonography, electroretinogram (ERG), and histological studies by light microscopy were also performed at the end of 8 weeks.

RESULTS

The novel artificial vitreous body consists of a thin vitreous-like capsule with a silicone tube-valve system. The capsule can be folded and implanted into vitreous cavity through 1.5 mm incision on sclera. Physiological balanced solution (PBS) was then injected into the capsule and inflated to support retina and control intraocular pressure (IOP) through the tube-valve system subsequently fixed under the conjunctiva. Experiments using rabbits showed that the novel vitreous body could effectively support the retina and apparently induced no significant pathological changes in the eye over 8 weeks.

CONCLUSION

This approach may provide a new research strategy in the vitreous replacement technology. The novel artificial vitreous body device can effectively support retina, control IOP, and has good biocompatibility. It may be a good alternative to injecting artificial vitreous although its tamponade properties and usefulness still have to be proven in complex vitreoretinal diseases.

Ion chromatographic analysis of tetracyclines using polymeric column and acidic eluent

High-performance ion chromatography (HPIC) is first successfully used to analyze tetracycline antibiotics (TCs) in this work. The TCs are well separated on a solvent compatible polymeric cation-exchange column within 12 min. Isocratic elution with acetonitrile-hydrochloride is very advantageous for routine analysis. HPIC may be seen as a specific variant of the more common high-performance liquid chromatography (HPLC) for water-soluble and polar pharmaceuticals with low hydrophobicity. The detection limits (signal-to-noise ratio=3:1) of oxytetracycline (OTC), tetracycline (TC), chlortetracycline (CTC), doxycycline (DC) are 10, 10, 20 and 20 microg l(-1), respectively. Samples are prepared by vortex mixing with an ethylenediaminetetraacetic acid disodium salt (Na2EDTA)-McIlvaine buffer (pH 4.0) solution and the mixture filtrates through a molecular weight cut-off filter. The method has been successfully applied to monitor the OTC removal rate through every reactor in the process of OTC manufacturing wastewater treatment by bio-chemical technology. It is also applicable to determine the TCs residues in milk and milk powder with satisfying results.

Stem cell factor, the JAK-STAT pathway and signal transduction

Recent work has demonstrated the importance of Janus family kinases (JAKs) and signal transducers and activators of transcription (STATs) in the stimulus-response coupling of receptors lacking intrinsic tyrosine kinase activity. In particular, the JAK-STAT pathway appears critical in signal transduction by interferon as well as numerous hematopoietic growth factors interacting with members of the hemapoietin receptor superfamily. Although ligands that interact with receptor tyrosine kinases (RTK), such as epidermal growth factor (EGF), platelet-derived growth factor (PDGF) and colony stimulating factor-1 (CSF-1), have been shown to induce increases in phosphorylation of both JAKs and STATs, little is known about activation of this pathway by stem cell factor (SCF). This review will summarize what is known about the JAK/STAT pathway in relation to SCF signal transduction.

On-line pretreatment and determination of Pb, Cu and Cd at the microgram l-1 level in drinking water by chelation ion chromatography

A novel, highly sensitive method for the simultaneous separation and determination of lead, copper, cadmium and other transition metals in drinking water was achieved by on-line sample pretreatment of chelation ion chromatography. Manganese, which coeluted with cadmium, was oxidized to permanganate by ammonium persulfate before injection. Permanganate, with bulk quantity of alkali, alkaline earth metals, iron and aluminum, was eliminated by pyrophosphoric acid-ammonium acetate buffer solution (pH 5.5), while retaining heavy and transition metals on a selective chelating resin (MetPac CC-1 column). Then, they were disabsorbed and transferred to a sulfonated cation exchanger (TMC-1 column). Finally, the concentrated trace metals were separated on a bifunctional ion-exchange column (CS5A) by a concentration gradient of oxalic acid and sodium nitrate eluents, coupled with post-column spectrophotometric detection with 2-[(5-bromo-2-pyridyl)azo]-5-diethylaminophenol (5-Br-PADAP) at 560 nm. The separation and color-development conditions were optimized. The detection limits for the method (signal-to-noise ratio = 3:1) were at or below the microgram l-1 level. The results of drinking water analyses were satisfactory.

Characterization of Antibody-Drug Conjugate Pharmacokinetics and in Vivo Biotransformation Using Quantitative Intact LC-HRMS and Surrogate Analyte LC-MRM

Antibody-drug conjugates (ADCs) pose challenges to bioanalysis because of their inherently intricate structures and potential for very complex catabolism. Common bioanalysis strategy is to measure the concentration of ADCs and Total Antibody (Ab) as well as deconjugated warhead in circulation. The ADCs and the Total Ab can be quantified with ligand binding assays (LBA) or with hybrid immunocapture-liquid chromatography coupled with multiple reaction monitoring mass spectrometry (LBA-LC-MRM). With the LBA-LC-MRM approach, a surrogate analyte, often the signature peptide, and released warhead can be used for the quantification of the Total Ab and ADCs, respectively. Recent advances in analytical instrumentation, especially the development of high resolution mass spectrometers (HRMS), have enabled characterization and quantification of intact macromolecules such as ADCs. The LBA-LC-HRMS approach employs immunocapture, followed by chromatographic separation at the macromolecule level and detection of the intact analyte. We developed an intact quantification method with 1-10 μg/mL linear dynamic range using 25 μL of plasma sample volume. This method was qualified for the measurement of naked monoclonal antibody (mAb), a site-specific cysteine-conjugated ADC with drug to antibody ratio ∼2 (DAR2) and a site-nonspecific cysteine-conjugated ADC (DAR8) in rat plasma. Samples from a rat pharmacokinetic (PK) study were analyzed with both methods. For the naked mAb, the results from both assays matched well. For ADCs, new species were observed from the LBA-HRMS method. The results demonstrated that potential biotransformation of the ADC was unveiled using the intact quantification approach while not being observed with traditional LBA-LC-MRM approach. Our work demonstrated an application of novel intact quantification by supporting animal PK studies. Moreover, our results suggest that the intact quantification method can provide novel perspectives on ADC in vivo characterization and quantification, which can benefit future drug candidate optimization as well as the immunogenicity impact evaluation and safety assessment.

Capillary zone electrophoresis-electrospray ionization-tandem mass spectrometry for quantitative parallel reaction monitoring of peptide abundance and single-shot proteomic analysis of a human cell line

We coupled capillary zone electrophoresis (CZE) with an ultrasensitive electrokinetically pumped nanospray ionization source for tandem mass spectrometry (MS/MS) analysis of complex proteomes. We first used the system for the parallel reaction monitoring (PRM) analysis of angiotensin II spiked in 0.45mg/mL of bovine serum albumin (BSA) digest. A calibration curve was generated between the loading amount of angiotensin II and intensity of angiotensin II fragment ions. CZE-PRM generated a linear calibration curve across over 4.5 orders of magnitude dynamic range corresponding to angiotensin II loading amount from 2amole to 150fmole. The relative standard deviations (RSDs) of migration time were <4% and the RSDs of fragment ion intensity were ∼20% or less except 150fmole angiotensin II loading amount data (∼36% RSD). We further applied the system for the first bottom up proteomic analysis of a human cell line using CZE-MS/MS. We generated 283 protein identifications from a 1h long, single-shot CZE MS/MS analysis of the MCF7 breast cancer cell line digest, corresponding to ∼80ng loading amount. The MCF7 digest was fractionated using a C18 solid phase extraction column; single-shot analysis of a single fraction resulted in 468 protein identifications, which is by far the largest number of protein identifications reported for a mammalian proteomic sample using CZE.

Photoprotection in the green tidal alga Ulva prolifera: role of LHCSR and PsbS proteins in response to high light stress

Ulva prolifera, an intertidal macroalga, has to adapt to wide variations in light intensity, making this species particularly rewarding for studying the evolution of photoprotective mechanisms. Intense light induced increased non-photochemical quenching (NPQ) and stimulated de-epoxidation of xanthophyll cycle components, while DTT-treated samples had lower NPQ capacity, indicating that the xanthophyll cycle must participate in photoprotection. In this work, we found that the PsbS-related NPQ was maintained in U. prolifera. According to analysed gene expression, both LhcSR and psbS were up-regulated in high light, suggesting that these two genes are light-induced. LHCSR and PsbS proteins were present at different light intensities and accumulated under high light conditions, and PsbS concentrations were higher than LHCSR, showing that the NPQ mechanism of U. prolifera is more dependent on PsbS protein concentration. Moreover, the level of both LHCSR and PsbS proteins was high even in the darkness, and neither the transcript level nor protein content of LhcSR and psbS genes varied significantly following short-term exposure to intense light. These findings suggest that this alga can modulate NPQ levels through regulation of the xanthophyll cycle and concentrations of PsbS and/or LHCSR.

Accurate determination of peptide phosphorylation stoichiometry via automated diagonal capillary electrophoresis coupled with mass spectrometry: proof of principle

While reversible protein phosphorylation plays an important role in many cellular processes, simple and reliable measurement of the stoichiometry of phosphorylation can be challenging. This measurement is confounded by differences in the ionization efficiency of phosphorylated and unphosphorylated sites during analysis by mass spectrometry. Here, we demonstrate diagonal capillary electrophoresis-mass spectrometry for the accurate determination of this stoichiometry. Diagonal capillary electrophoresis is a two-dimensional separation method that incorporates an immobilized alkaline phosphatase microreactor at the distal end of the first capillary and employs identical electrophoretic separation modes in both dimensions. The first dimension is used to separate a mixture of the phosphorylated and unphosphorylated forms of a peptide. Fractions are parked in the reactor where they undergo complete dephosphorylation. The products are then periodically transferred to the second capillary and analyzed by mass spectrometry (MS). Because the phosphorylated and unphosphorylated forms differ in charge, they are well resolved in the first dimension separation. Because the unphosphorylated and dephosphorylated peptides are identical, there is no bias in ionization efficiency, and phosphorylation stoichiometry can be determined by the ratio of the signal of the two forms. A calibration curve was generated from mixtures of a phosphorylated standard peptide and its unphosphorylated form, prepared in a bovine serum albumin tryptic digest. This proof of principle experiment demonstrated a linear response across nearly 2 orders of magnitude in stoichiometry.

JAK2 is constitutively associated with c-Kit and is phosphorylated in response to stem cell factor

Stem cell factor (SCF) interacts with the receptor tyrosine kinase c-Kit and has potent effects on hematopoiesis. We have examined the role of JAK2 in the SCF signal transduction pathway. JAK2 and c-Kit were constitutively associated, and treatment with SCF resulted in rapid and transient tyrosine phosphorylation of JAK2. Incubation of cells with JAK2 antisense oligonucleotides resulted in significant decreases in SCF-induced proliferation. These data suggest that JAK2 plays a role in SCF-induced proliferation.

Retention behavior of transition metals on a bifunctional ion-exchange column with oxalic acid as eluent

The common eluents used with a bifunctional ion-exchange column (IonPac CS5A) for separating transition metals are pyridine-2,6-dicarboxylic acid and oxalic acid (Ox). When Ox is used, cadmium and manganese co-elute. Although much research has been done to overcome the Cd2+-Mn2+ co-elution problem, the role of lithium hydroxide in separating the transition metals has received little attention. In this study, it is found that when the Ox concentration is higher than 35 mM, Cu2+ elutes after Pb2+ and Ox plays a predominant role in the retention behavior of the seven metals. When Ox concentration is lower than 35 mM especially when its concentration (25 mM) is half of the usually used standard concentration (50 mM), Cu2+ elutes before Pb2+, and at the same time, Mn2+ and Cd2+ can also be baseline separated. Lithium hydroxide plays a predominant role in the separation of the metals separated by cation exchange. So, lithium hydroxide is used to adjust the pH of the eluent. The use of an isocratic elution (25 mM Ox/LiOH/2 mM Na2SO4, pH 3.88) allows the separation of seven metals (Cu2+, Pb2+, Co2+, Mn2+, Cd2+, Zn2+ and Ni2+) in a single run. The effects of inorganic modifiers such as NaNO3, Na2SO4 and Na4P3O7 on retention behavior of the metals are also investigated.

Coupling immobilized alkaline phosphatase-based automated diagonal capillary electrophoresis to tandem mass spectrometry for phosphopeptide analysis

Automated diagonal capillary electrophoresis is a two-dimensional separation method that incorporates an immobilized enzyme reactor at the distal end of the first capillary and employs identical electrophoretic separation modes in both dimensions. Components undergo a preliminary separation in the first capillary. Fractions are parked in the reactor where some components undergo transformation. The fractions are then periodically transferred to the second capillary and replaced by the next components in the sample. Components that are not modified by the reactor will have identical mobility in both dimensions and fall on the diagonal of a reconstructed two-dimensional electropherogram, while analyte that undergoes modification will fall off the diagonal. In this study, alkaline phosphatase was immobilized in a monolithic reactor. An LTQ-Orbitrap Velos mass spectrometer was used to monitor analytes as they migrated from the second capillary. The system was used to characterize the phosphorylation status of a tryptic digest of α-casein in a background prepared from a 22-fold excess of the tryptic digest of bovine serum albumin. 120 fractions underwent automated treatment in the alkaline phosphatase reactor and separation in the second dimension capillary for over 40 min; nine phosphorylated α-casein peptides that produced 20 different phosphorylation states were detected with high confidence.

Uncovering immobilized trypsin digestion features from large-scale proteome data generated by high-resolution mass spectrometry

Immobilized trypsin produces very fast protein digestion, which is attractive for application to high throughput bottom-up proteomics. While there is a rich literature on the preparation of immobilized trypsin, there are very few studies that investigate its application to complex proteomic samples. In this work, we compared solution-phase trypsin with trypsin immobilized on magnetic microspheres for digestion of two complex proteomes, Escherichia coli and the MCF7 cell line. The digests were separated by HPLC, and detected with a Q-Exactive mass spectrometer, which generated high resolution and high quality parent- and fragment-ion mass spectra. The data were analyzed using MaxQuant. We make several conclusions about the features of immobilized trypsin digestion of complex proteomes. First, both immobilized and solution-phase trypsin generate peptides that sample the same protein pool. Second, immobilized trypsin can digest complex proteomes two orders of magnitude faster than solution-phase trypsin while retaining similar numbers of protein identifications and proteome depth. Digestion using immobilized trypsin for 5-min produces a similar number of missed cleavages as solution-based trypsin digestion for 4-h; digestion using immobilized trypsin for 20-min produces a similar number of missed cleavages as solution-based trypsin digestion for 12-h. Third, immobilized trypsin produces quantitatively reproducible digestion of complex proteomes. Finally, there is small but measurable loss of peptide due to non-specific adsorption to the immobilization matrix. This adsorption generates a bias against detection of basic peptides.

Bioanalytical Methods and Strategic Perspectives Addressing the Rising Complexity of Novel Bioconjugates and Delivery Routes for Biotherapeutics

In recent years, an increase in the discovery and development of biotherapeutics employing new modalities, such as bioconjugates or novel routes of delivery, has created bioanalytical challenges. The inherent complexity of conjugated molecular structures means that quantification of the bioconjugate and its multiple components is critical for preclinical/clinical studies to inform drug discovery and development. Moreover, bioconjugates involve additional multifactorial complexity because of the potential for in vivo catabolism and biotransformation, which may require thorough investigations in multiple biological matrices. Furthermore, excipients that enhance absorption are frequently evaluated and employed for the development of oral and inhaled biotherapeutics. Risk-benefit assessments are required for novel or existing excipients that utilize dosages above previously approved levels. Bioanalytical methods that can measure both excipients and potential drug metabolites in biological matrices are highly relevant to these emerging bioanalysis challenges. We discuss the bioanalytical strategies for analyzing bioconjugates such as antibody-drug conjugates and antibody-oligonucleotide conjugates and review recent advances in bioanalytical methods for the quantification and characterization of novel bioconjugates. We also discuss bioanalytical considerations for both biotherapeutics and excipients through novel administration routes and review analyses in various biological matrices, from the extensively studied serum or plasma to tissue biopsy in the context of preclinical and clinical studies from both technical and regulatory perspectives.

Use of ion chromatography for the determination of heavy and transition metals in biochemical samples

A novel, highly sensitive method for simultaneous separation and determination of Cu2+, Ni2+, Zn2+, Cd2+, Co2+, Mn2+ and Pb2+ in biochemical samples was developed and evaluated by ion chromatography. All of these metals were well separated on a bifunctional ion-exchange column by a concentration gradient of oxalic acid and sodium chloride eluents, coupled with spectrophotometric detection after post-column derivatization with 2-[(5-bromo-2-pyridyl)azo]-5-diethylaminophenol at 560 nm. The method detection limits (signal-to-noise 3:1) were at microg l(-1) levels. The calibration graphs were linear (r2>0.999) over two-orders of magnitude. This technique was optimized and validated by analyzing five standard biochemical references.

Effects of albumin on ionized calcium in vitro

Human serum albumin is used to treat hypoproteinemia in neonates or used as a volume expander. We tested the hypothesis that the addition of human serum albumin to neonatal serum decreases the serum ionized calcium (iCa) concentration. Concentrated human serum albumin was added to 12 placental and cord serum samples to reach seven incremental concentrations from 0 to 20.0 g/L. Serum iCa concentration decreased significantly with the addition of serum albumin. From multiple regression analysis, the effect of albumin addition on serum iCa concentration had more marked effects at high baseline albumin or low baseline Ca concentrations. From this in vitro study, we speculate that fast infusion of albumin in human neonates has the potential for acutely lowering serum iCa concentration.

Comparison of clindamycin phosphate vaginal cream with triple sulfonamide vaginal cream in the treatment of bacterial vaginosis

BACKGROUND

Triple sulfonamide vaginal cream has been used to treat bacterial vaginosis for many years. There are few studies in which triple sulfonamide cream has been compared with newer regimens.

GOAL

To compare the efficacy and safety of clindamycin phosphate vaginal cream with that of triple sulfonamide vaginal cream in the treatment of bacterial vaginosis.

STUDY DESIGN

In this double-blind, randomized multicenter study, nonpregnant women 16 years of age or older with symptomatic bacterial vaginosis were assigned to receive either 2% clindamycin phosphate vaginal cream or triple sulfonamide vaginal cream for 7 days. Follow-up visits were conducted 5 to 10 days and 25 to 39 days after completion of treatment.

RESULTS

Clinical cure or improvement at 25 to 39 days was noted in 55 (69.6%) of 79 assessable participants who received clindamycin vaginal cream and in 33 (41.8%) of 79 women who received triple sulfonamide vaginal cream (P < 0.0001). Most of the difference between the treatment groups was noted in women with a history of bacterial vaginosis. Among women without a history of bacterial vaginosis, clindamycin and triple sulfonamide creams had similar efficacy. Evaluation of Gram-stained vaginal smears correlated with clinical outcome. Most patients in both treatment groups reported an improvement in symptoms. No significant difference was observed between the treatment groups in the incidence of adverse events.

CONCLUSION

Clindamycin 2% vaginal cream is more effective than triple sulfonamide vaginal cream in the treatment of bacterial vaginosis.