Contaminants of emerging concern: Silylation procedures, evaluation of the stability of silyl derivatives and associated measurement uncertainty

Analyte range of gas chromatography-mass spectrometry (GC-MS), widely used in environmental analysis, can be significantly broadened by derivatization. Silyl derivatives have improved volatility and thermal stability, chromatographic and mass spectrometric behaviors, and thus detection, structural elucidation and quantification. However, silylation use is often hindered by the stability of generated derivatives and the need to optimize silylation conditions. In this study, we optimized the derivatization conditions for 70 selected contaminants of emerging concern (CEC) using chemometrics approaches. N-methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA), N, O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) and BSTFA + 1 % trimethylchlorosilane (TMCS) were investigated, among which the latter gave the best yield. CEC were grouped in three derivatization protocols: 60 °C/45 min, 70 °C/90 min, and 70 °C/45 min. The short- and long-term stability of the CEC-trimethylsilyl (TMS) derivatives, i.e. for 28 days and up to 20 weeks were examined in a solvent and artificial wastewater (AWW) extract at 25 °C, 4 °C and - 18 °C, and during repeated five freeze-thaw (F/T) cycles, at two concentration levels: 100 μg/L and 1000 μg/L. Except for TMS derivatives of shikimic acid (SHA), quinic acid (QA) and sulfanilamide (SFA), the remaining derivatized compounds were stable in solvent (EtAc) for 28 days. In AWW extract, TMS derivatives of citric acid (CA), 17β-estradiol (E2), estriol (E3) and 17α-ethinyl estradiol (EE2) were unstable at 25 °C and 4 °C. Within up to 20 weeks, only the TMS derivatives of CA, meso-erythritol (ERY) and bisphenol BP (BPBP) were unstable. The most significant hydrolytic breakdown was observed during repeated F/T cycles. After three cycles, ≤ 20 % of the initial concentration of six and nine CEC-TMS derivatives had degraded in solvent and AWW extracts, respectively. According to the deep statistical comparison (DSC) approach, the most prominent degradation was observed for TMS derivatives of E2, CA, 9-hydroxyfluorene (9-HF), estrone (E1) and trans-3'-hydroxycotinine (T3HC) in solvent; E2, CA, 9-HF, E3 and E1 in AWW extracts and ERY, E2, CA, 9-HF and E1 in both matrices. Finally, the sample concentration of CEC accounted for most of the measurement uncertainty (MU). Based on our findings, we recommend the derivatized samples to be stored at -18 °C for up to 20 weeks to ensure the stability of their TMS derivatives. Sample freezing and thawing of not more than twice is allowed to maintain ≥80 % of the initial CEC-TMS concentration.

Serology and longevity of immunity against Echinococcus granulosus in sheep and llama induced by an oil-based EG95 vaccine

An oil-based formulation of the EG95 vaccine to protect grazing animals against infection with Echinococcus granulosus was formulated in Argentina. The efficacy of the vaccine was monitored by serology in sheep and llama (Lama glama) and was compared to the serology in sheep previously published using a QuilA-adjuvanted vaccine. Long-term efficacy was also tested in sheep by challenging with E. granulosus eggs of the G1 strain 4 years after the beginning of the trial. The serological results for both sheep and llama were similar to those described previously, except that there was a more rapid response after the first vaccination. A third vaccination given after 1 year resulted in a transient boost in serology that lasted for about 12 months, which was similar to results previously described. Sheep challenged after 4 years with three vaccinations presented 84·2% reduction of live cysts counts compared with control group, and after a fourth vaccination prior to challenge, this reduction was 94·7%. The oil-based vaccine appeared to be bio-equivalent to the QuilA vaccine.

Madness at the movies: prioritised movies for self-directed learning by medical students

OBJECTIVE

We aimed to systematically compile a list of 10 movies to facilitate self-directed learning in psychiatry by medical students.

METHOD

The selected areas were those of the top five mental health conditions from the Global Burden of Disease 2010 study. The search strategy for movies covered an extensive range of sources (published literature and websites), followed by closer examination and critical viewing of a sample.

RESULTS

Out of a total of 503 potential movies that were identified, 23 were selected for viewing and more detailed critique. The final top 10 were: for depressive and anxiety disorders: Ordinary People (1980), Silver Linings Playbook (2012); for illicit drug use: Trainspotting (1996), Winter's Bone (2010), Rachel Getting Married (2008), Half Nelson (2006); for alcohol use disorders: Another Year (2010), Passion Fish (1992); and for schizophrenia: The Devil and Daniel Johnston (2006), and An Angel at My Table (1990).

CONCLUSIONS

The final selection of 10 movies all appeared to have relatively high entertainment value together with rich content in terms of psychiatric themes. Further research could evaluate the extent to which medical students actually watch such movies, by assessing the level of withdrawals from a medical school library and surveying student responses.

Cardiopulmonary exercise testing predicts postoperative outcome in patients undergoing gastric bypass surgery

BACKGROUND

For several types of non-cardiac surgery, the cardiopulmonary exercise testing (CPET)-derived variables anaerobic threshold (AT), peak oxygen consumption (VO2 peak), and ventilatory equivalent for CO(2) (VE/VCO2 ) are predictive of increased postoperative risk: less physically fit patients having a greater risk of adverse outcome. We investigated this relationship in patients undergoing gastric bypass surgery.

METHODS

All patients (<190 kg) who were referred for CPET and underwent elective gastric bypass surgery at the Whittington Hospital NHS Trust between September 1, 2009, and February 25, 2011, were included in the study (n=121). Fifteen patients did not complete CPET. CPET variables (VO2 peak, AT, and VE/VCO2 ) were derived for 106 patients. The primary outcome variables were day 5 morbidity and hospital length of stay (LOS). The independent t-test and Fisher's exact test were used to test for differences between surgical outcome groups. The predictive capacity of CPET markers was determined using receiver operating characteristic (ROC) curves.

RESULTS

The AT was lower in patients with postoperative complications than in those without [9.9 (1.5) vs 11.1 (1.7) ml kg(-1) min(-1), P=0.049] and in patients with a LOS>3 days compared with LOS ≤ 3 days [10.4 (1.4) vs 11.3 (1.8) ml kg(-1) min(-1), P=0.023]. ROC curve analysis identified AT as a significant predictor of LOS>3 days (AUC 0.640, P=0.030). The VO2 peak and VE/VCO2 were not associated with postoperative outcome.

CONCLUSIONS

AT, determined using CPET, predicts LOS after gastric bypass surgery.

Rural residents' utilisation of health and visiting specialist health services

INTRODUCTION AND OBJECTIVES

The purpose of the study was to identify the demographic and health service characteristics impacting on rural residents' utilisation of health and visiting specialist services in Western Australia.

METHOD

Focus group discussions were held with an age-stratified, randomly selected group of forty-eight residents in four rural Western Australian towns between May and June 2000.

RESULTS

Discussions revealed a preference to use local health services for basic care and to travel for the treatment of major or severe illnesses. The focus group participants supported visiting specialist services, indicating a willingness to use them for consultations, diagnostic and minor procedures. Utilisation of visiting services was conditional on the provision of information on specialist reputation, service outcomes, integration of the service into local facilities, and recommendation by the local general practitioner.

CONCLUSION

Numerous factors influence the service-seeking behaviour of rural patients. These factors need to be recognised and considered in the design and promotion of resident and visiting specialist services if the migration for health care is to be rationalised.

Evaluation of newborn screening for medium chain acyl-CoA dehydrogenase deficiency in 275 000 babies

OBJECTIVE

To evaluate newborn screening by tandem mass spectrometry for detection of medium chain acyl-CoA dehydrogenase (MCAD) deficiency, a fatty acid oxidation disorder with significant mortality in undiagnosed patients.

DESIGN

The following were studied: (a) 13 clinically detected MCAD deficient subjects, most homozygous for the common A985G mutation, whose newborn screening sample was available; (b) 275 653 consecutive neonates undergoing routine newborn screening. Screened infants with blood octanoylcarnitine levels > or = 1 micromol/l were analysed for the A985G mutation, had analysis of plasma and repeat blood spot acylcarnitines and urinary organic acids, and had fibroblast fatty acid oxidation or acylcarnitine studies.

RESULT

Twelve of the 13 patients later diagnosed clinically had newborn octanoylcarnitine levels > 2.3 micromol/l. Twenty three screened babies had initial octanoylcarnitine levels > or = 1 micromol/l. Eleven of 12 babies with persistent abnormalities had metabolite and/or enzyme studies indicating MCAD deficiency. Only four were homozygous for the A985G mutation, the remainder carrying one copy.

CONCLUSIONS

Most patients with symptomatic MCAD deficiency could be detected by newborn screening. Infants actually detected had a lower frequency of A985G alleles than clinically diagnosed cases and may have a lower risk of becoming symptomatic.

Evaluation of an automated culture system for detecting bacterial contamination of platelets: an analysis with 15 contaminating organisms

BACKGROUND

Approximately 1 in 2000 platelet components are bacterially contaminated. The time to detection of 15 seeded organisms in platelets recovered from an automated culture system was studied.

STUDY DESIGN AND METHODS

Isolates of Bacillus cereus, Bacillus subtilis, Candida albicans, Clostridium perfringens, Corynebacterium species, Enterobacter cloacae, Escherichia coli, Klebsiella oxytoca, Propionibacterium acnes, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, Serratia marcescens, Streptococcus pyogenes, and Streptococcus viridans were inoculated into Day 2 apheresis platelet components to obtain a final concentration of approximately 10 and 100 CFU per mL (2 units/organism). Each bag was sampled 10 times (20 mL/sample). Four mL of each sample was inoculated into standard aerobic and anaerobic bottles and into aerobic and anaerobic bottles containing charcoal; 2 mL was inoculated into pediatric aerobic bottles (so as to maintain a 1:10 ratio of sample to media) and 1 mL into thioglycollate broth.

RESULTS

With the exception of P. acnes, all organisms were detected in a mean of 9.2 to 25.6 hours. A range of 10 serial dilutions in inoculating concentrations was associated with an overall 10.1-percent difference in detection time. A mean of 74.4 and 86.2 hours (100 and 10 CFU/mL inocula, respectively) was required for the detection of P. acnes in anaerobic bottles.

CONCLUSION

Bacteria thought to be clinically significant platelet contaminants can be detected in 9.2 to 25.6 hours when the starting concentration is approximately 10 to 100 CFU per mL. P. acnes required considerably longer incubation times for detection (in either aerobic or anaerobic bottles). However, P. acnes is of questionable clinical significance. Such a detection system could be used in either a blood collection center or a transfusion service to screen platelet concentrates for bacterial contamination. Such testing (with sterile sampling performed so as to maintain a closed-bag system) would be expected to save lives and might allow an extension of platelet storage.

Role of the cross-linking enzyme tissue transglutaminase in the biological recognition of synthetic biodegradable polymers

The calcium-dependent cross-linking enzyme tissue transglutaminase (tTgase, type II) is a potential novel player at the cell surface, where its contribution to cell adhesion and stabilization of the extracellular matrix is becoming increasingly recognized. We investigated whether tTgase enhances the biological recognition of poly (DL lactide co-glycolide) (PLG), poly (epsilon-caprolactone) (PCL), and poly (L lactide) (PLA), biomaterials widely used in medical implants. Three cell-model systems consisting of human osteoblasts, endothelial cells (ECV-304), and Swiss 3T3 fibroblasts were utilized, in which tTgase expression was modulated by gene transfer, and the ability of cells to spread on these polymers was quantified in relation to the altered level of expressed tTGase. Results show that over-expression of tTgase in human osteoblasts positively correlated with cell spreading on PLG, while no attachment and spreading was found on PCL and PLA. Antisense silencing of tTgase in the endothelial cells led to a marked reduction of cell spreading on all polymers. The hydrophobic nature of PLC also appeared to favor endothelial cell attachment. Spreading of Swiss 3T3 fibroblasts on these biomaterials was only slightly affected by increased expression of tTgase, although cell spreading on control glass was increased. We propose that the consideration of tTgase-mediated bioactivity in novel biomaterials may improve cell attachment and promote biocompatibility.

The effect of high altitude on platelet counts, thrombopoietin and erythropoietin levels in young Bolivian airmen visiting the Andes

Recognition of thrombosis as a complication of exposure to high altitude has stimulated interest in rheological changes resulting from hypobaric hypoxia. Previous studies of platelet counts at high altitude have yielded conflicting results and have not been studied in conjunction with potential mediating cytokines. We studied the effects of high-altitude exposure on platelet numbers, thrombopoietin (tpo) and erythropoietin (epo) levels in man. A group of 28 volunteers from the Bolivian Airforce stationed at Santa Cruz (600 m altitude) were studied 48 h and 1 week after their ascent to La Paz (3600 m). In addition 105 volunteers based at Santa Cruz for at least 1 year were compared with 175 age- and sex-matched residents at El Alto (4200 m). Platelet counts were measured immediately after sampling and serum samples assayed for tpo and epo. In the ascending group, mean platelet counts were 251 x 10(9), 367 x 10(9) and 398 x10 (9)/l at 600 m and following 48 h and 1 week at 3600 m respectively. Mean tpo levels were 132.5, 76 and 92 pg/ml with epo values of 2.98, 11.6 and 7.9 mIU/ml respectively. In the resident populations mean platelet counts were 271 x 10(9)/l in the low- and 471 x 10(9)/l in the high-altitude groups. Mean tpo and epo levels measured 69.3 pg/ml and 4.5 mIU/ml respectively at 600 m and 58.5 pg/ml and 5.1 mIU/ml at 4200 m. In conclusion we have demonstrated a significant and sustained elevation in platelet numbers within 48 h of ascent to high altitude. Our findings do not support a role for tpo as a mediator of the increased platelet count. However, these data do not discount epo as a potential candidate.

Phase I and pharmacokinetic study of intraperitoneal topotecan

OBJECTIVE

To determine the maximum tolerated dose and pharmacokinetics of topotecan when administered by the intraperitoneal route.

METHODS

A dose-escalating Phase I trial was conducted in which fifteen % of the total dose was given as an intraperitoneal bolus in two litres of D5W and the remainder was given as a continuous intraperitoneal infusion over 24 hours. Treatments were given every 21 days. Pharmacokinetic analyses were performed at the recommended phase II dose.

RESULTS

Seventeen patients received a total of 43 cycles at 21-day intervals. The maximum tolerated dose was 4 mg/m2 and acute dose-limiting toxicity was neutropenia. Other toxicities included leukopenia, anemia, emesis, fever, and abdominal pain. Although no objective responses were achieved, five of ten patients with ascites had a decrease in fluid accumulation with administration of intraperitoneal topotecan. The recommended phase II dose is 3 mg/m2. Pharmacokinetic analysis performed at a dose of 3 mg/m2 demonstrated that elimination from the peritoneal cavity followed second-order kinetics with k1 = 1.6 hr(-1), k2 = 0.3 hr(-1) and first and second-phase half-lives of 0.49 and 2.7 hours, respectively. Plasma pharmacokinetic behavior was best described by first-order kinetics with k = 0.5 hr(-1) and a half-life of 3.9 hours. The pharmacologic advantage, expressed as the peritoneal to plasma AUC ratio was 31.2.

CONCLUSIONS

Intraperitoneal administration of topotecan at 3 mg/m2 results in a substantial increase in drug exposure for the peritoneal cavity without compromising systemic exposure; this may be beneficial for the treatment of patients with ovarian cancer or intraperitoneal carcinomatosis.

Immunohistochemical analysis of the distribution of the human ATPase (hASNA-I) in normal tissues and its overexpression in breast adenomas and carcinomas

Human ATPase (hASNA-I) is a novel human gene recently cloned on the basis of homology to the arsA gene of bacteria. Its protein product is an ATPase that is free in the cytoplasm and bound in the perinuclear area and nucleolus in human cells. We prepared the hASNA-I-specific 5G8 monoclonal antibody and used it to investigate the expression of hASNA-I in normal human tissues and breast cancers. hASNA-I was detected immunohistochemically only in the epithelial cells of the liver, kidney, and stomach wall, in the adrenal medulla, in the islet cells of the pancreas, in the red pulp of the spleen, and in cardiac and skeletal muscle. No staining was observed in the uterus, testis, lung, thyroid, cerebellum, and large intestine. Although no staining was also observed in normal breast tissue, all four cases of breast fibroadenomas and all 15 cases of either primary or metastatic breast carcinoma demonstrated increased staining. No embryological or functional common denominator is readily apparent. However, the increased expression in malignant breast cells is of particular interest with respect to the use of this antibody for screening of cytological specimens.

Weak anamnestic responses of inbred mice to Yersinia F1 genetic vaccine are overcome by boosting with F1 polypeptide while outbred mice remain nonresponsive

The role of immunity to intracellular Ags in resistance to infection by Yersinia is not well established. The enteropathogenic bacteria Yersinia pseudotuberculosis and Yersinia enterocolitica actively translocate Ags to the cytosol of eukaryotic cells. Whereas Yersinia pestis does not always express the requisite cellular adhesins, results have varied as to whether similar cytosolic translocation of Ags occurs in vitro. We used a genetic vaccine to induce intracellular expression of the fraction 1 (F1) capsular protein of Y. pestis within host mammalian cells and examined the ensuing immune response. The F1 genetic vaccine stimulated only weak CTL responses in BALB/c mice. Substantial Ab responses to the F1 genetic vaccine were obtained in all inbred strains of mice tested, but Ab levels were less than those resulting from vaccination with the F1 polypeptide. In contrast, outbred mice did not respond to the F1 plasmid, suggesting that some inbred mouse strains may exhibit exaggerated responses to plasmid vaccines. A primary immunization with the F1 genetic vaccine followed by a boost with recombinant F1 polypeptide produced a vigorous Ab response from inbred mice that was equivalent to three injections of F1 polypeptide. We conclude that cytosolic expression of the F1 Ag efficiently primes immunity, while secondary exposure to the F1 polypeptide is required for optimal Ab induction.

Dual cytoplasmic and nuclear distribution of the novel arsenite-stimulated human ATPase (hASNA-I)

The arsenite-stimulated human ATPase (hASNA-I) protein is a distinct human ATPase whose cDNA was cloned by sequence homology to the Escherichia coli ATPase arsA. Its subcellular localization in human malignant melanoma T289 cells was examined to gain insight into the role of hASNA-I in the physiology of human cells. Immunocytochemical staining using the specific anti-hASNA-I monoclonal antibody 5G8 showed a cytoplasmic, perinuclear, and nucleolar distribution. Subcellular fractionation indicated that the cytoplasmic hASNA-I was soluble and that the perinuclear distribution was due to association with the nuclear membrane rather than with the endoplasmic reticulum. Its presence in the nucleolus was confirmed by showing colocalization with an antibody of known nucleolar specificity. Further immunocytochemical analysis showed that the hASNA-I at the nuclear membrane was associated with invaginations into the nucleus in interphase cells. These results indicate that hASNA-I is a paralogue of the bacterial ArsA protein and suggest that it plays a role in the nucleocytoplasmic transport of a nucleolar component.

Chromosomal localization and genomic structure of the human arsenite-stimulated ATPase (hASNA-I)

The hASNA-I is a novel human arsenite-stimulated ATPase identified as the human paralogue of the ATPase component of the arsenite efflux system in E. coli. The hASNA-I has distinct biochemical properties and a dual nuclear and cytoplasmic distribution. Immunohistochemical staining showed a distinct pattern of hASNA-I expression in cells within normal tissues, and its overexpression in breast cancer. Recently, the yeast two-hybrid system has identified hASNA-I as a cellular partner of metallothionein II suggesting an additional role in Zn homeostasis and cellular detoxification. This report describes the assignment of hASNA-I to human chromosome 19 by somatic-cell hybrid PCR mapping, the isolation of a chromosome 19-specific cosmid clone, and the genomic structure and exon-intron boundaries of hASNA-I. Our results indicate that the coding region of hASNA-I consists of 4 exons spanning 6 kb on band 19q13.3. These data will facilitate molecular analysis of the role of hASNA-I in human disease.

Biochemical characterization of the human arsenite-stimulated ATPase (hASNA-I)

Arsenic is a potent toxin and carcinogen. In prokaryotes, arsenic detoxification is accomplished by chromosomal and plasmid-borne operon-encoded efflux systems. We have previously reported the cloning of hASNA-I, a human homologue of arsA encoding the ATPase component of the Escherichia coli arsenite transporter. Purified glutathione S-transferase (GST)-hASNA-I fusion protein was biochemically characterized, and its properties were compared with those of ArsA. The GST-hASNA-I exhibited a basal level of ATPase activity of 18.5 +/- 8 nmol/min/mg in the absence of arsenite. Arsenite produced a 1.6 +/- 0.1-fold stimulation of activity (p = 0. 0044), which was related to an increase in Vmax; antimonite did not stimulate activity. Two lines of evidence suggest that an oligomer is the most likely native form of hASNA-I. First, lysates of human embryo kidney 293 cells overproducing recombinant hASNA-I produced a single monomeric 37-kDa band on SDS-polyacrylamide gel electrophoresis (PAGE) and two distinct species when analyzed using nondenaturing PAGE. Second, chemical cross-linking of the 63-kDa GST-hASNA-I resulted in the formation of dimeric and tetrameric protein forms. The results indicate that hASNA-I is a distinct human arsenite-stimulated ATPase belonging to the same superfamily of ATPases represented by the E. coli ArsA protein.

Autozygosity mapping, to chromosome 11q25, of a rare autosomal recessive syndrome causing histiocytosis, joint contractures, and sensorineural deafness

We describe a highly consanguineous family, originating from Pakistan, displaying histiocytosis, joint contractures, and sensorineural deafness. The form of histiocytosis exhibited by this family does not fit readily into any of the recognized classes of this disease. It appears to represent a novel form of familial histiocytosis demonstrating autosomal recessive inheritance. Using autozygosity mapping, we have identified a homozygous region of approximately 1 cM at chromosome 11q25, in affected individuals. A maximum two-point LOD score of 3.42 (recombination fraction straight theta = .00) was obtained with marker D11S968. This is the first genetic locus to be described that is involved in the molecular pathogenesis of histiocytosis.

Lack of IL-1 receptor antagonistic activity of the capsular F1 antigen of Yersinia pestis

Because capsular F1 antigen of Yersinia pestis is reported to share sequence homology with interleukin-1 receptor antagonist (IL-1ra), we investigated the potential IL-1 receptor antagonistic activity of F1 on human endothelial cells (EC). The biological activities of IL-1 receptor antagonist (IL-1ra) or IL-1ra-like molecule were measured by its ability to suppress the IL-1beta-mediated induction of adhesion molecules (ICAM and ELAM) on EC and of IL-6 secretion by these cells. Two different, purified, immunogenic and biologically active preparations of F1, at concentrations up to 10-fold higher than that of IL-1ra, did not exhibit any inhibitory activities of IL-1ra. These F1 preparations also did not activate peripheral blood mononuclear cells to produce IL-4 or IL-10, cytokines which might downregulate pro-inflammatory cytokine production in response to infection. Thus, even though there is a high degree of similarity between F1 antigen and IL-1ra in three-dimensional structure by computer modeling and sequence homology, our work indicates that F1 antigen of Y. pestis does not have IL-1ra-like activity.

Synergy between cisplatin and an inhibitor of S-adenosylmethionine dependent transmethylation in human ovarian adenocarcinoma cells

Selection of cells for resistance to cisplatin results in resistance to arsenite and selenite. Mammalian cells detoxify arsenite and selenite by S-adenosylmethionine dependent methylation. We aimed to investigate whether S-adenosylmethionine dependent methylation is involved in the cellular metabolism of cisplatin. Treatment of human ovarian cancer cells 2008 and the cisplatin-resistant subline 2008/C13*5.25 with the S-adenosylhomocysteine hydrolase inhibitor adenosine-dialdehyde, an indirect inhibitor of transmethylation, resulted in a significant elevation (16-fold in 2008, 6-fold in 2008/C13*5.25) in the cellular content of S-adenosylhomocysteine without changing S-adenosylmethionine. Adenosine dialdehyde synergistically enhanced the cytotoxicity of cisplatin and carboplatin as evidenced by combination indices <1 using the combination index-isobologram method in clonogenic assays with 2008 human ovarian adenocarcinoma cells. However, the cellular accumulation, efflux, steady state content, and the formation of DNA adducts of the cisplatin [H-3]-DEP were not affected by adenosine-dialdehyde. Sodium arsenite was significantly more toxic in mice pretreated with adenosine-dialdehyde, whereas the toxicity of cisplatin remained unchanged. These studies suggest that inhibition of S-adenosylmethionine dependent transmethylation enhanced the toxicity of cisplatin and carboplatin to human ovarian carcinoma cells in vitro without directly affecting the metabolism of either platinum drug.

Digitonin enhances the efficacy of carboplatin in liver tumour after intra-arterial administration

Platinum-containing drugs enter the cell slowly and have a poor tissue penetration. Increasing the permeability of the cell membrane might increase the intracellular drug concentration. Digitonin, a detergent that increases cell permeability by binding to cholesterol molecules in the cell membrane, can increase cisplatin accumulation and reduce tumour growth in vitro. The aim of this study was to determine whether digitonin could increase the efficacy of carboplatin (CBDCA) in vivo. In LH rats, a hepatoma was implanted in the liver. At 7 days after implantation, digitonin (or saline in the control group) was infused via the hepatic artery and, 10 min later, CBDCA was injected. Biopsies from the tumour and liver parenchyma were obtained after 1 h. The concentration of platinum measured in the liver tumours was higher in the digitonin group than in the control groups. In the liver parenchyma the concentrations were of the same magnitude. Measured with the 133Xe-clearance technique, digitonin did not alter the tumour blood flow. Digitonin enhanced the tumour-growth-retarding effect of CBDCA given intra-arterially at 5 mg/kg but not at 25 mg/kg. No increase in toxicity was observed for digitonin given together with CBDCA at 5 mg/kg. Systemic administration of CBDCA was not influenced by digitonin. These findings demonstrate that pretreatment with digitonin increases the tumour uptake of CBDCA and potentiates the cytotoxic effect of CBDCA.

Isolation of the ATP-binding human homolog of the arsA component of the bacterial arsenite transporter

Arsenite resistance in bacteria is mediated by an efflux pump composed of the arsA and arsB gene products. We have isolated the human homolog of the bacterial arsA (hARSA-I), a member of the ATPase superfamily with no transmembrane domain. Southern and Northern analyses indicated the presence of two cross-hybridizing genes in the human genome and expression of hARSA-I in many tissues. A rabbit antiserum raised against a glutathione-S-transferase (GST)/hARSA-I fusion protein identified two cross-reacting proteins of 37 and 42 kDa by Western analysis in two different human cell lines. Overexpression of hARSA-I in the embryonal human kidney 293 cell line was accompanied by overproduction of the 37-kDa protein Biochemical analysis using the GST/hARSA-I fusion protein indicated that hARSA-I is an ATPase analogous to the bacterial ArsA. Thus, hARSA-I is a new eukaryotic member of a highly conserved ATP-binding superfamily of proteins.

Vasopressin modulation of peritoneal, lymphatic, and plasma drug exposure following intraperitoneal administration

i.p. administration of cytotoxic drugs for the treatment of regionally confined cancers results in a greater total drug exposure [area under the concentration x time curve (AUC)] for the peritoneal fluid and regional lymphatics than for plasma. We sought to augment the relative advantage of i.p. administration further through modulation of peritoneal clearance by reduction in splanchnic blood flow. Pigs were treated with 5-fluorouracil, etoposide (VP-16), and carboplatin (CBDCA) alone by the i.p. route or with the same drugs in combination with i.v. lypressin, a synthetic vasopressin analogue, which reduces splanchnic blood flow. Drug concentrations in peritoneal fluid, plasma, and thoracic duct lymph were monitored over the ensuing 6 h. The pharmacokinetics of 5-fluorouracil were not altered by vasopressin; however, vasopressin increased the peritoneal fluid:plasma AUC ratio for CBDCA from 30.6 +/- 5.6 to 70. 6 +/- 7.4 (P < 0.01) and increased the lymph:plasma AUC ratio from 1.1 +/- 0.4 to 2.6 +/- 0.22 (P < 0.05). In the case of VP-16, vasopressin increased the peritoneal fluid:plasma AUC ratio from 129 +/- 35 to 350 +/- 76 (P < 0.05) and the lymph:plasma AUC ratio from 2.1 +/- 0.6 to 10.6 +/- 3.5 (P < 0.05). Concurrent i.v. administration of vasopressin can increase the pharmacokinetic advantage of the i.p. route of administration of CBDCA and VP-16 markedly in the pig model. These data suggest that the strategy of concurrent i.p. administration of CBDCA or VP-16 plus an agent that reduces splanchnic blood flow may increase the dose intensity in the abdominal cavity and intraabdominal lymphatic tissue substantially without increasing systemic toxicity.

Three-dimensional helical CT of intrahepatic venous structures: comparison of three rendering techniques

OBJECTIVE

To define the advantages and disadvantages of various rendering techniques to obtain three-dimensional (3D) displays of intrahepatic venous structures with helical CT data.

MATERIALS AND METHODS

After rapid preprocessing segmentation of the liver, helical CT data (8 mm slice thickness overlapped every 4 mm) from 10 patients were reconstructed using maximum intensity projection (MIP), volume rendering, and surface rendering algorithms. Three-dimensional imaging was evaluated blindly and independently by three observers for presence of artifacts and overall quality.

RESULTS

Three-dimensional displays showed the hepatic veins and fifth order portal branches with the volume and MIP rendering techniques. Best overall quality in the 3D representation of the liver was achieved with the MIP technique (p < 0.05). Small details in venous anatomy and portal involvement by tumor were better imaged with the MIP technique. "Stair-step" artifacts markedly degraded the 3D displays obtained with the surface rendering technique, making it inappropriate for imaging the intrahepatic venous structures.

CONCLUSION

Maximum intensity projection appears to be an adequate technique to perform 3D imaging of intrahepatic venous structures with helical CT data when 8 mm slice thicknesses overlapping every 4 mm are used. However, optimization of imaging protocols needs to be done and compared in a larger series.

Ultrastructure of rat pulmonary arterioles after neonatal exposure to hypoxia and subsequent relief and treatment with monocrotaline

A group of rats was born in and spent the first 4 weeks of life at a simulated altitude of 3550 m. Two animals were killed immediately afterwards and the remaining 16 were allowed to recover for various times up to a maximum of 12 weeks at sea-level atmospheric pressure. On ultrastructural examination, the pulmonary arterioles of hypoxic rats showed muscularization, the new layer of mature smooth muscle cells containing abundant organelles and myofilaments. These cells were bounded by prominent elastic laminae. During the recovery period, the medial layer became progressively thinned, but the cells still retained some characteristics of smooth muscle by 12 weeks' recovery. When a similar group of ten hypoxic rats was allowed to recover for 12 weeks before being given monocrotaline, there was early enlargement of the residual smooth muscle cells in the media of pulmonary arterioles and within 5 weeks there was again a thick layer of medial smooth muscle. This was in contrast to the sparse, weakly muscularized arterioles seen in eight similarly treated rats born under normoxic conditions. The relevance is discussed of these findings to the rare occurrence of primary pulmonary hypertension in people who were born at high altitude but returned to sea-level during childhood.

Enlargement of the carotid bodies in cirrhosis of the liver

The carotid bodies were dissected out at necropsy and weighed in seven subjects with cirrhosis of the liver and in seven control subjects of comparable age free of liver disease. The mean combined carotid body weight of the control group was 17 mg but in the cirrhotic patients it was 35 mg, a statistically significant difference (P < 0.005). Differential counts of the various types of glomic cell (progenitor, dark and light variants of chief cells and sustentacular cells) were carried out. The enlargement of the carotid bodies in the subjects with cirrhosis was associated with increased numbers of the dark variant of chief cell. The mean number of dark cells per unit area in the control group was 361 cells/mm2 but in the cirrhosis group it was 1024 cells/mm2, a statistically significant difference (P < 0.005). It is postulated that the prominence of dark cells may be associated with secretion of a natriuretic peptide in response to the hyperaldosteronism and sodium retention of cirrhosis of the liver. Alternatively, it may be a response to hypoxaemia resulting from porta-pulmonary shunts.

Ultrastructural differences between pulmonary arteriolar muscularization induced by hypoxia and monocrotaline

A group of Wistar rats was treated with two subcutaneous injections of monocrotaline, at 4 and 6 weeks of age. They were then killed 1 month after the initial injection. A second group of rats was born and reared in hypobaric hypoxia for 1 month before being killed. Both groups had age-matched controls. The ultrastructure of pulmonary arterioles from all groups was studied, and quantitative measurements were made of the volume densities of organelles within the cytoplasm of arteriolar smooth muscle cells. The pulmonary arterioles of rats treated with monocrotaline contained immature smooth muscle cells with coarse peripheral myofilaments and were bounded by thin indistinct elastic laminae. In contrast, the arteriolar smooth muscle cells of hypoxic rats were mature with fine myofilaments and bounded by electron dense laminae. When compared with both their respective controls and the alternative test group, the muscle cells from rats treated with monocrotaline had significantly lower volume densities of dense bodies, and the hypoxic muscle cells had significantly higher densities of mitochondria. The pulmonary arteriolar muscularization in rats would appear to be a nonuniform process producing smooth muscle cells with differing cytoplasmic features that suggest differing cellular functions.

Pretransplant clinicopathological correlation in end-stage primary pulmonary hypertension

The aim of the study was to see if there was any correlation between the histopathology, ultrastructure, pulmonary endocrinology and clinical manifestations of end-stage primary pulmonary hypertension. Twenty patients undergoing heart-lung transplantation for the disease were studied. The nature and duration of symptoms and signs, results of haematological, electrocardiographic, radiographic, echocardiographic and haemodynamic studies, and the response of patients to vasodilators were compared with data from histopathological and ultrastructural study of lungs removed at transplantation. Length of clinical history and clinical evidence of severe disease were not necessarily associated with advanced histopathology, nor did the presence of small, contracted muscular pulmonary arteries imply responsiveness to vasodilators. Numbers of gastrin-releasing peptide-containing pulmonary endocrine cells were greater in lungs in which there was activity of myofibroblasts in pulmonary arterial vessels, and correlated negatively with mean pulmonary artery pressure and pulmonary artery systolic pressure. Whereas the prognosis of primary pulmonary hypertension cannot as yet be defined by other than its clinical manifestations, intimal proliferation as well as vasoconstriction may be important in its pathogenesis. The release of gastrin-releasing peptide from pulmonary endocrine cells may possibly be involved in this process.

The carotid bodies enlarge in some cases of cirrhosis of the liver

The weights of the individual carotid bodies and cardiac ventricles were obtained at necropsy in five series of subjects. The first comprised 10 cases free of cardiopulmonary disease to act as controls. The second consisted of 10 cases of pulmonary emphysema. The third was composed of 8 cases characterized by sustained alveolar hypoxia due to causes other than pulmonary emphysema. The fourth comprised 10 cases of systemic hypertension or severe left ventricular failure. The fifth was made up of 10 cases of diseases of the liver or alimentary canal. The study confirmed that enlargement of the carotid bodies is common in cases of pulmonary emphysema or sustained alveolar hypoxia with right ventricular hypertrophy. It is also common in cases of systemic hypertension with left ventricular hypertrophy. It was also revealed that enlargement of the carotid bodies may occur in cirrhosis of the liver. We believe this to be the first report of that association.

Phase I and pharmacokinetic study of intraperitoneal ormaplatin

Ormaplatin is a cisplatin analog which has demonstrated activity against cisplatin-resistant tumors in preclinical studies. We delivered 28 cycles to 14 patients in a phase I trial of intraperitoneal ormaplatin given every 28 days. The maximum tolerated dose was 88.4 mg/m2 and acute dose-limiting toxicity was abdominal pain. Other toxicities include nausea, emisis, fever, and severe neuropathy seen in 1 patient at a cumulative dose of 399 mg/m2. No objective responses were observed. Hematologic toxicity was mild. The dose recommended for future trials of intraperitoneal ormaplatin is 66.5 mg/m2. Pharmacokinetic analysis performed at a dose of 66.5 mg/m2 demonstrated that the initial phase of elimination from the peritoneal cavity follows first-order kinetics with k = 0.69 hr-1 and half-life of 1.4 hr. Plasma pharmacokinetic behavior is best described by biexponential model with k1 = 0.369 hr-1, k2 = 0.107 hr-1, and first half-life of 2.9 hr and second half-life of 8.4 hr. Pharmacologic advantage, calculated by ratio of peritoneal to plasma AUC, is 17.1. If site-specific activity is demonstrated, then the intraperitoneal route of administration of ormaplatin at 66.5 mg/m2 may be beneficial.

The development of the nerve network in the fetal human carotid body and its subsequent function in cardiac disease

Carotid bodies from 17 human fetuses of gestational age ranging from 10 weeks to full term were examined in histological sections stained by the Bodian silver protargol method to demonstrate nerve axons. At 10 weeks gestation the carotid body was contacted by a single nerve bundle at its apical pole but by the 13th week a second bundle had also reached the proximal pole. Thin, pale nerve axons extended from these bundles and surrounded the carotid body to form a plexus from which several small groups of axons entered its superficial regions. With increase of gestational age beyond this point there was a progressive influx of axons to penetrate the innermost areas of glomic tissue by the 19th week. Nerve endings were not identified until 23 weeks gestation when occasional small boutons, and rarely calyces, were seen to terminate on fetal chief cells. Thus there was by this age a well-developed nerve link between glomus and brain consistent with the view that from this stage of development the carotid bodies are able to function as chemoreceptors. However, results of previous research work in our Department and in the literature lead us to believe that the fully anatomically developed nerve network of the carotid body depends on its cellular and biochemical environment to ensure that it functions efficiently as a chemoreceptor. Thus, reduction of dopamine-turnover or attenuation of chief cells in the carotid bodies is associated with increased chemosensitivity, as in the days following birth and in systemic hypertension in later life.(ABSTRACT TRUNCATED AT 250 WORDS)

The earliest histopathological response to hypobaric hypoxia in rabbits in the Rifugio Torino (3370 M) on Monte Bianco

Twelve Dutch rabbits were kept on Monte Bianco at an altitude of 3370 m. Half of the animals were killed after 3 months, the remainder after 6 months, and a further six animals maintained at sea-level acted as controls. The carotid bodies of all the rabbits were processed for light and electron microscopy and examined qualitatively and quantitatively. The lungs were processed for light microscopical assessment of small pulmonary arterial vessels; the thickness of the pulmonary trunks and aortas were measured; and the hearts were dissected to obtain ratios of the ventricular weight. There was a slight increase in the right ventricular weight in the hypoxic rabbits but no change in the thickness of the pulmonary trunk compared with that of the aorta. In particular, there was no hypoxic remodelling of the pulmonary vasculature such as muscularization of pulmonary arterioles or intimal longitudinal muscle in pulmonary arteries. The earliest histopathological response to hypoxia occurred in the carotid bodies in the form of an increase in the count of the dark variant of chief cell after 3 months which returned to normal after 6 months. It is concluded that the carotid body of the rabbit responds with a change in its population of dark chief cells to a level of hypoxia which is insufficient to affect the pulmonary arterioles. Changes in the cardiopulmonary system can no longer be considered to be the earliest histopathological response to hypobaric hypoxia.

Arachnoid nodules in the lungs of high altitude Indians

BACKGROUND

Nodules of cells showing a striking histological similarity to those of arachnoid villi have previously been found closely adjacent to pulmonary venules in several diseases associated with alveolar hypoxia or pulmonary oedema including mitral stenosis, plexogenic pulmonary arteriopathy, pulmonary thromboembolism, and chronic obstructive pulmonary disease.

METHODS

Histological sections of the lungs of seven adult native highlanders from La Paz (3600 m) were examined.

RESULTS

Arachnoid nodules were found in the lungs of one Aymara and one Mestizo Indian.

CONCLUSIONS

These bodies may have a similar function to that of arachnoid granulations which transfer excess cerebrospinal fluid to the dural venous sinuses. In the native highlanders it is possible that they contribute to the avoidance of excessive hydration of the interstitial tissue of the alveolar walls with return of fluid into the pulmonary venules, preventing incipient pulmonary oedema.

Modulation of cisplatin cytotoxicity by permeabilization of the plasma membrane by digitonin in vitro

Killing of human ovarian carcinoma 2008 cells by cisplatin (DDP) is in direct proportion to the amount of drug entering the cell. DDP and its analogue [3H]dichloro(ethylenediamine)platinum[II] ([3H]-DEP) enter cells relatively slowly. We found that the uptake of [3H]DEP into 2008 cells could be increased by treating the cells briefly with the plasma membrane-selective detergent digitonin. A similar effect was observed in an 11-fold DDP-resistant subline of 2008 cells, designated 2008/C13*5.25. A measurable effect was produced by concentrations as low as 5 microM, and 40 microM digitonin increased [3H]DEP accumulation at 1 hr by 4.4 +/- 0.2- and 6.5 +/- 0.7-fold (means +/- SD) in 2008 and 2008/C13*5.25 cells, respectively. The effect was rapid, occurring within 1 min. Increased [3H]DEP uptake was accompanied by increased platination of DNA (8.5-fold in 2008 cells and 18.5-fold in 2008/C13*5.25 cells), and by enhanced killing of both the DDP-sensitive and -resistant cells that was shown to be synergistic by median effect analysis. The combination index at 50% cell kill was 0.64 +/- 0.14 (values < 1 indicate synergy). We conclude that a brief exposure to digitonin can increase [3H]DEP uptake in vitro, and can overcome the impaired [3H]DEP accumulation associated with acquired DDP resistance. DDP and digitonin interact synergistically to increase tumor cell kill in vitro.

Enhanced response to antigen within lymph nodes of SJL/J mice that were protected against experimental allergic encephalomyelitis by T cell vaccination

The effects of T cell vaccination on peripheral immune responsiveness are not yet fully understood. We have induced resistance to rat spinal cord homogenate (RSCH)-induced experimental allergic encephalomyelitis (EAE) in SJL/J mice by vaccination with four T cell lines (RZ8, RZ15, RZ16, and A51) which were reactive to myelin basic protein (MBP) but not to proteolipid protein (PLP). The effect was relatively neuroantigen-specific since vaccination with ovalbumin (OVA)-reactive and alloantigen-specific cells did not prevent EAE induction. Alloantigen-reactive cells reduced the rate of relapse. The number of central nervous system (CNS) infiltrates and mean clinical EAE scores were significantly reduced. This is the first report demonstrating T cell vaccination in the SJL/J mouse, a strain in which PLP is the predominant encephalitogen in RSCH. The vaccinating cells were of the memory/effector (CD44high, CD45RBlow) surface phenotype. We examined the effect of T cell vaccination on lymph node T cell proliferative responses to MBP, encephalitogenic peptides of PLP and MBP, OVA and anti-CD3. With the exception of polyclonal cytokine responses to anti-CD3, which remained unchanged, vaccination led to a 5-10-fold augmentation in all, including background, responses. By comparison with lymph node cell (LNC) responses from naive mice and mice primed with OVA, it appeared that T cell vaccination restored cellular activation levels which had been depleted in peripheral lymphoid tissues of unvaccinated animals with EAE.

Pulmonary endocrine cells of Aymara Indians from the Bolivian Andes

INTRODUCTION

There is evidence to suggest that life at high altitude causes changes in the population of pulmonary endocrine cells, possibly because of exposure to chronic hypoxia. A study was made of the populations of pulmonary endocrine cells in three Aymara Indians and three Mestizos of La Paz (3600 m), Bolivia, which were compared with those in four white lowlanders.

METHODS

Pulmonary endocrine cells were immunolabelled for neurone specific enolase and their two major secretory products, gastrin releasing peptide and calcitonin, and their numbers expressed per cm2 of tissue section.

RESULTS

No differences in morphology, number, content, or distribution of immunoreactive cells were found when the native highlanders were compared with the lowlanders.

CONCLUSIONS

If chronic hypoxia as such exerts an influence on human pulmonary endocrine cells it was not apparent in this morphological study. There was no increase in gastrin releasing peptide containing pulmonary endocrine cells, such as have previously been seen in patients with pulmonary hypertension characterised by plexogenic pulmonary arteriopathy. This may be due to the fact that in plexogenic pulmonary arteriopathy there is free migration of smooth muscle cells. Although three of the highlanders in this present study showed pulmonary vascular remodelling, this was in contrast only modest.