Effects of acid treatment on the trace metal content of chromatographic silica: bulk analysis, surface analysis and chromatographic performance of bonded phases

A series of studies has been carried out on the effect of refluxing silica chromatography particles for 0.5 h and 18 h in water, dilute hydrochloric acid and dilute hydrofluoric acid. The bulk and surface trace metal concentrations were measured by inductively-coupled plasma atomic emission spectroscopy, static secondary ion mass spectrometry (SSIMS) and X-ray photoelectron spectroscopy. Diffuse reflectance Fourier transform infrared spectroscopy was used to determine changes in 'isolated" and "bonded" silanol groups. The chromatographic behaviour of a series of weakly basic analytes was investigated on C8 and C18 bonded phases manufactured from the acid-treated silicas. The different reflux treatments all resulted in a reduction in the numbers of isolated silanols compared with the untreated silica and SSIMS analysis suggested that the HF-treated silicas had undergone a more efficient surface rehydroxylation. Bulk trace metals were removed most effectively by the HF treatment, with the multivalent elements (Ti and Al) being the most difficult to remove. Surface specific analysis suggested that trace metals were removed more rapidly from the surface of the silica compared to the bulk matrix and that the acid treatments resulted in halide contamination of the silica surface. Evidence is presented to suggest that the bulk metal content of the silica is not representative of the concentration of metals at the chromatographic surface. The chromatographic investigations showed that the HF-treated silica gave substantially better performance towards weak bases than the HCl-treated silicas.

Smooth muscle tumor of the pleura. A case report and review of the literature

Smooth muscle tumors of the serosal membranes are extremely rare and have received little attention in the literature. To the best of our knowledge, only 1 published series of 5 pleural smooth muscle neoplasms has been published to date. We describe a primary pleural neoplasm with smooth muscle differentiation documented by light microscopy, immunohistochemistry, and electron microscopy. This tumor originated in the parietal pleura in a 32-year-old white man and was diagnosed incidentally by chest radiography; the diagnosis was confirmed by magnetic resonance imaging and biopsy. Four years later, the tumor was noted to have increased in size and disseminated into the chest wall as a separate circumscribed mass located in the pectoral muscle. Both masses were resected and diagnosed as smooth muscle tumors. We conclude that smooth muscle tumor of the pleura is a well-defined entity with a low, but definite malignant potential; therefore, we recommend complete resection and long-term follow-up for all patients.

Detection of unwanted residues of ivermectin in bovine milk by dissociation-enhanced lanthanide fluoroimmunoassay

Avermectins are frequently used to control parasitic infestations in many animal species. Previous studies have shown the long-term persistence of unwanted residues of these drugs in animal tissues and fluids. An immunoassay screening test for the detection and quantification of ivermectin residues in bovine milk has been developed. After an extensive extraction procedure, milk samples were applied to a competitive dissociation-enhanced lanthanide fluoroimmunoassay using a monoclonal antibody against an ivermectin-transferrin conjugate. The monoclonal antibody, raised in Balb C mice, showed cross-reactivity with eprinomectin (92%), abamectin (82%) and doramectin (16%). The limit of detection of the assay (mean + 3 SD), calculated from the analysis of 17 known negative samples, was calculated as 4.6 ng/mL. Intra- and inter-assay RSDs were determined as 11.6% and 15.8%, respectively, using a negative bovine milk sample fortified with 25 ng/mL ivermectin. Six Friesian milking cows were treated with ivermectin, three with a pour-on formulation of the drug and three with an injectable solution at the manufacturer's recommended dose rate. An initial mean peak in ivermectin residue concentration was detected at day 4 (mean level = 47.5 ng/mL) and day 5 post-treatment (mean level = 26.4 ng/mL) with the injectable form and pour-on treatment, respectively. A second peak in residue concentration was observed using the DELFIA procedure 28 days post-treatment in both treatment groups (23.1 ng/mL injectable and 51.9 ng/mL pour-on). These second peaks were not confirmed by HPLC and must at this time be considered to be false-positive results. By day 35 after treatment the mean ivermectin residue concentration of both groups fell below the limit of detection of the assay.

A clinical nomogram for predicting long-term survival in advanced colorectal cancer

From our prospectively accrued database of patients with gastrointestinal cancer, 1057 patients with advanced colorectal cancer were identified with the aim of determining predictive factors for survival of greater than 2 years and to use this information to develop a predictive nomogram. Patient's baseline characteristics, type and number of chemotherapy regimens received, and response to chemotherapy were assessed by univariate and multivariate logistic regression comparing those who survived greater than or less than 2 years. A total of 161 (15.2%) patients survived more than 2 years, so-called long survivors (LS). In multivariate analysis, positive predictive factors for LS were: good performance status (PS), normal serum carcinoembryonic antigen (CEA), rectal primary, Dukes' stage A-B, well or moderate differentiation, two or less disease sites, response to chemotherapy and treatment used protracted venous infusion (PVI) 5-fluorouracil (5-FU) in first-line chemotherapy, and the increasing number of chemotherapy treatments received. From these PS, CEA, number of sites and response to first-line chemotherapy were used to develop a nomogram capable of predicting the probability of survival beyond 2 years for an individual patient. This large study confirmed the relevance of known prognostic factors in metastatic colorectal cancer and demonstrated the importance of response to chemotherapy as an independent factor to predict LS. By combining these, we developed a nomogram which provides information which is likely to prove useful in the management of patients with advanced colorectal cancer.

Effects of growth hormone treatment on red cell plasma membrane fatty acid constituents in hypopituitary adults

The effects of replacement with recombinant human GH (hGH) on red cell plasma membrane fatty acid and cholesterol constituents were assessed in nine adult patients with growth hormone deficiency. They were treated with hGH in a dose of 0.125 U.kg-1.wk-1 for four weeks and at 0.25 U.kg-1.wk-1 thereafter for an overall mean duration 13.5 +/- 3.9 months (mean +/- SD). The relative proportions of the various phospholipid fatty acid constituents and the proportion of cholesterol in the phospholipid bilayer were assayed every six months. At the end of the study, the percentage of arachadonic acid (20:4) in membrane phospholipid was found to rise by an average of 3.7% (P < 0.05) and there appeared to be a nonsignificant trend showing an increase in highly unsaturated fatty acids, namely linoleate (18:2) and gamma linolenic acid (18:3) and a corresponding decrease in unsaturated fatty acids, namely palmitate (16:0) and stearate (18:0) and monounsaturated fatty acids such as palmitoleic acid (16:1), oleic acid (18:1) and oleic acid isomer (18:1 iso). In addition, the proportion of cholesterol in the plasma membrane i.e. the cholesterol/phospholipid ratio was found to decrease by 0.84% (P < 0.05). There was a significant increase in HbAlc from 4.85 +/- 0.51 to 4.94 +/- 0.45% (P < 0.01) by the end of the study.

Quantitative approach to single-nucleotide polymorphism analysis using MALDI-TOF mass spectrometry

Pooling of DNA samples before genotyping is a valuable means of streamlining large-scale genotyping efforts in disease association studies, single-nucleotide polymorphism (SNP) validation or mutant allele screening programs. In this report, we explore the application of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to quantitative analysis of SNPs. The measurements are based on MALDI-TOF MS analysis of primer extension assays performed on standard mixtures of pooled PCR products at several test loci. The inherent high molecular weight resolution of MALDI-TOF MS conveys high specificity and good signal-to-noise ratio for performing accurate quantitation. The methods described maximize the sensitivity and quantitative capacity of MALDI-TOF MS while preserving the throughput and economic advantages of the MALDI-TOF platform. Using the format described, we demonstrate that allele frequencies as low as 5% can be detected quantitatively and unambiguously.

Oncological applications of gene therapy

Despite the rapid technological advances that continue to sustain the field of cancer gene therapy, few individual patients have benefited from the revolution so far. The plethora of clinical trials described confirms that each malignancy will have its own ideal strategy based on the associated molecular defects, and there has been rapid progress from this viewpoint. At the same time, there has been a renewed appreciation for the limitations to gene therapy, which include low efficiency of gene transfer, poor specificity of response and methods to accurately evaluate responses, and lack of truly tumor-specific targets at which to aim. As with all new therapies, we are climbing a steep learning curve in terms encountering treatment-related toxicities, as well as profound ethical and regulatory issues.

Implementing the Agency for Health Care Policy and Research's Smoking Cessation Guideline in a lung cancer surgery clinic

PURPOSE/OBJECTIVES

To determine the effectiveness of a nurse-managed smoking cessation intervention based on the Agency for Health Care Policy and Research's (AHCPR's) Smoking Cessation Guideline in a lung cancer surgery clinic.

DESIGN

Quasi-experimental.

SETTING

Urban, Midwest, academic, and tertiary care.

SAMPLE

25 adult male and female smokers with a confirmed diagnosis of lung cancer that had been surgically managed. Subjects were assigned to an intervention group (n = 14) or a usual-care group (n = 11).

METHODS

Participants in the intervention group received a nurse-delivered, AHCPR-based smoking cessation intervention that included face-to-face and phone follow-up contact beginning with the first preoperative clinic consultation. Usual-care participants received routine care provided at the institution.

MAIN RESEARCH VARIABLES

Self-reported smoking status with expired air carbon monoxide confirmation six months postsurgery.

FINDINGS

Seventy-one percent of the intervention group was biochemically confirmed to be abstinent by expired air carbon monoxide, as compared to 55% in the usual-care group.

CONCLUSIONS

Smokers diagnosed with lung cancer desired to quit smoking and may benefit from an intensive smoking cessation intervention at time of diagnosis.

IMPLICATIONS FOR NURSING PRACTICE

Further research should include continuing evaluation of an intensive smoking cessation intervention with this population, and all clinicians should be trained to implement AHCPR's Smoking Cessation Guideline in practice.

Gene therapy: recent progress in the clinical oncology arena

Despite the rapid technological advances that continue to sustain the field of cancer gene therapy, few individual patients have benefited from the revolution so far. The plethora of clinical trials described confirms that each malignancy will have its own ideal strategy based on the associated molecular defects, and there has been rapid progress from this viewpoint. At the same time, there has been a renewed appreciation for the limitations to gene therapy, which include low efficiency of gene transfer, poor specificity of response and methods to accurately evaluate responses, and lack of truly tumor-specific targets at which to aim. As with all new therapies, we are climbing a steep learning curve in terms encountering treatment-related toxicities, as well as profound ethical and regulatory issues.

Clinical report on long-term bone density after short-term EMF application

A 1984 study determined the effect of a 72 Hz pulsating electromagnetic field (PEMF) on bone density of the radii of post-menopausal (osteoporosis-prone) women, during and after treatment of 10 h daily for 12 weeks. Bone mineral densities of the treated radii increased significantly in the immediate area of the field during the exposure period and decreased during the following 36 weeks. Bone density determination of the radii of these women, remeasured after eight years, suggests no long-term changes. The bone density-enhancing effect of PEMFs should be further studied, alone and in combination with exercise and pharmacologic agents such as the bisphosphonates and hormones, as prophylaxis in the osteoporosis-prone postmenopausal woman and as a possible block to the demineralization effect of microgravity.

An EEG coherence test of the frontal dorsal versus ventral hypothesis in N-back working memory

We examined Goldman-Rakic's conceptualization of working memory (WM) involving modality-specific reverbatory circuits using electrophysiological measures. An n-back WM task, with either spatial information or object information to be remembered, was administered with EEG coherence used to provide a functional measure of corticocortical communication. Support was not found for modality-specific WM systems in this task. Instead, results suggest that there is a circuit that connects dorsal frontal with dorsal parietal areas which is activated during all levels of the WM vigilance task, regardless of the type of stimuli involved. Data also suggest that left frontal areas are sensitive to the level of difficulty of the WM task (0,1,2, and 3-back), as well as familiarity of task demands. Overall, our results support a model that conceptualizes a unitary WM system rather than a system composed of separate WM circuits for different modalities.

Transesophageal echocardiographic identification of left subclavian artery stenosis with steal phenomenon

In this report, we present the first case of the transesophageal echocardiographic identification of left subclavian artery stenosis and steal phenomenon.

Chromatographic aspects in high throughput liquid chromatography/mass spectrometry

Important parameters to consider when developing a liquid chromatography/mass spectrometry (LC/MS) method are buffer type and concentration, and column geometry. In the work presented here the choice of buffer for the analysis of basic compounds using a polar embedded phase (HyPURITYtrade mark ADVANCE) is illustrated for the analysis of tricyclic antidepressants. Method transfer from a 4.6 mm i.d. column to a 2.1 mm i.d. column is demonstrated for the analysis of triazines and anabolic steroids and their metabolites, with no change in selectivity and with added speed of analysis. Analysis of eight beta-blockers is achieved in 65 seconds by using a short 30 x 4.6 mm C18 column.

The study of the process of fluid-phase endocytosis in cervical squamous cells using fluorescent microspheres

Physiological processes in cervical squamous epithelium have not been extensively studied. Perhaps understandably, most of the research has concentrated on the pathology of the cervix, in particular dysplasia and malignancy. Fluid-phase endocytosis is a physiological process which has been demonstrated to be important in understanding disease development at other squamous epithelial sites, e.g. oesophagus. In this study, we have demonstrated by a new methodology developed in our laboratory using fluorescent microspheres and flow cytometry that fluid-phase endocytosis occurs in cervical squamous cells. The process has been shown to be dose- and time-dependent. This novel approach provides a means to improve our understanding of the physiological functions of the cervix and may provide insight into the pathogenesis of cervical neoplastic and non-neoplastic disease.

Improving electrotransfection efficiency by post-pulse centrifugation

We have demonstrated that the viability of electrotransfected adherent CHO and suspended NK-L, K-562, L1210 and MC2 cells is improved if pelleting by centrifugation is performed immediately after pulsing. The protection effect on cell viability is cell line- and pellet thickness-dependent. For forming CHO cell pellets, centrifugation force (300-13,000 g) and duration are not crucial; about five to 10 cell layers in the pellet provide the optimal protection effect. NK-L, K-562, L1210 and MC2 cell pellets are optimally formed by centrifugation at 13,000 g in an Eppendorf desktop centrifuge. Pelleting improves the cell viability over the whole range of the NK-L, K-562, L1210 and MC2 cell concentrations studied. When this pelleting method is applied to load CHO cells with FITC-dextran (41,000 MW), not only is the success rate close to 100%, but the growth rate is similar to the control, which is far better than the conventional electroporation method. Furthermore, the transfection efficiency of the five cell lines in pellet is significantly higher than that in suspension.

Cloning and localization of Rab3 isoforms in bovine, rat, and human parathyroid glands

Rab3 proteins are small GTP-binding proteins known to play a role in regulated exocytosis processes. This study examines the expression of Rab3 mRNA and protein in bovine, rat and human parathyroid glands. mRNAs of several Rab3 isoforms were detected in bovine (Rab3A, Rab3B and Rab3C) and rat (Rab3A, Rab3B and Rab3D) parathyroid glands by RT-PCR and sequencing. Rab3A protein was detected in the cytosolic extract from bovine parathyroid gland by Western blotting using a monoclonal antibody for Rab3A. Rab3A protein was localized to parathyroid hormone-containing chief cells by immunohistochemical staining. Subcellular localization of Rab3A protein by immunogold electron microscopy revealed that the majority of Rab3A protein was not associated with dense-core vesicles, but localized in the cytosol of the chief cells. Altogether, our results demonstrate that Rab3 isoforms are expressed in parathyroid chief cells, suggesting that they may play a role in regulated exocytosis in these cells.

Labetalol does not lengthen asystole during electroconvulsive therapy

Labetalol, a combined alpha- and beta-adrenergic blocker is often used to attenuate the transient increases in heart rate and blood pressure that accompany electroconvulsive therapy (ECT). It has been suggested that labetalol should not be administered during ECT without the protection provided by anticholinergic medications, because of its potential severe bradycardic effects. We present our experience with 32 patients from all age groups who received labetalol without anticholinergic treatment during ECT. None of the patients demonstrated adverse bradycardic effects. We conclude that administration of labetalol during ECT does not routinely require premedication with anticholinergic drugs and does not lengthen asystole.

High level multiplex genotyping by MALDI-TOF mass spectrometry

A primer extension assay is used to perform highly multiplexed genotyping of single nucleotide polymorphisms (SNPs) present in genomic DNA amplified by a multiplex PCR. The assay uses matrix-assisted laser desorption ionization time-of-flight mass spectrometry to accurately measure the masses of short oligonucleotide primers extended by a single dideoxynucleotide. The multiplexed genotyping assays rely on the natural molecular weight differences of DNA bases. By careful analysis of primer composition complementary to the target, or by judicious addition of one or more noncomplementary 5' bases to the genotyping primers, mass spectra of interleaved genotyping products can be generated with no ambiguity in allele assignment. Using a model multiplex PCR system, we demonstrate the ability to perform 12-fold multiplex SNP analysis.

Three cdg operons control cellular turnover of cyclic di-GMP in Acetobacter xylinum: genetic organization and occurrence of conserved domains in isoenzymes

Cyclic di-GMP (c-di-GMP) is the specific nucleotide regulator of beta-1,4-glucan (cellulose) synthase in Acetobacter xylinum. The enzymes controlling turnover of c-di-GMP are diguanylate cyclase (DGC), which catalyzes its formation, and phosphodiesterase A (PDEA), which catalyzes its degradation. Following biochemical purification of DGC and PDEA, genes encoding isoforms of these enzymes have been isolated and found to be located on three distinct yet highly homologous operons for cyclic diguanylate, cdg1, cdg2, and cdg3. Within each cdg operon, a pdeA gene lies upstream of a dgc gene. cdg1 contains two additional flanking genes, cdg1a and cdg1d. cdg1a encodes a putative transcriptional activator, similar to AadR of Rhodopseudomonas palustris and FixK proteins of rhizobia. The deduced DGC and PDEA proteins have an identical motif structure of two lengthy domains in their C-terminal regions. These domains are also present in numerous bacterial proteins of undefined function. The N termini of the DGC and PDEA deduced proteins contain putative oxygen-sensing domains, based on similarity to domains on bacterial NifL and FixL proteins, respectively. Genetic disruption analyses demonstrated a physiological hierarchy among the cdg operons, such that cdg1 contributes 80% of cellular DGC and PDEA activities and cdg2 and cdg3 contribute 15 and 5%, respectively. Disruption of dgc genes markedly reduced in vivo cellulose production, demonstrating that c-di-GMP controls this process.

Adiposity and blood pressure in a multiethnic population of women in Hawaii

OBJECTIVE

To compare the amount and distribution of fat among White, Japanese, Filipino and Hawaiian women and to investigate associations between measures of adiposity and serum cholesterol and blood pressure.

DESIGN

Cross-sectional survey of adiposity, serum cholesterol and blood pressure of 421 volunteer women of White (N = 137), Japanese (N = 144), Filipino (N = 74) and Hawaiian (N = 66) ethnicities, age 25-35 years. Anthropometric measures (weight; height; subscapular, bicep, tricep, suprailiac and calf skinfold thickness; waist, hip and mid-upper arm circumferences), grip strength, serum cholesterol and blood pressure.

RESULTS

Hawaiian women had the highest levels of adiposity by all measures. Asian women (especially Filipinos) had higher subscapular skinfold thicknesses than did Whites and, for the same value of body mass index (BMI), had a greater percentage of body fat. BMI was the strongest correlate of systolic blood pressure, while subscapular skinfold thickness was the strongest correlate of diastolic blood pressure. Blood pressure varied by adiposity but not ethnicity. No measures of body fat were associated with serum cholesterol.

CONCLUSION

Higher body fat measures, especially BMI, were associated with higher systolic blood pressure. However, higher subscapular skinfold (upper body) thickness was also associated with higher diastolic blood pressure. Subscapular fatness appears to be especially important among women of Asian ethnicity, Filipino women in particular.

The Royal Marsden experience of a small bowel adenocarcinoma treated with protracted venous infusion 5-fluorouracil

The purpose of this study was to review the efficacy of a protracted venous infusion of 5-fluorouracil (PVI 5-FU)-based chemotherapy in advanced small bowel adenocarcinoma. Data on all patients with small bowel malignancy who were seen at a single institution over a 5-year period were retrieved from the gastrointestinal unit and hospital databases, and these cases were reviewed. Eight patients with advanced small bowel adenocarcinoma received PVI 5FU-based chemotherapy. The overall response rate in assessable patients was 37.5% (3/8). The median overall survival was 13 months (range 1-28), and progression-free survival was 7.8 months (range 0-15). Overall, the treatment was well tolerated and symptomatic benefit was seen. In conclusion, PVI 5-FU has activity in this disease. This should be assessed either as a single agent or as part of a combination regimen such as epirubicin/cisplatin/PVI FU (ECF) in a multicentre randomized study.