Defining, Measuring and Preventing the Diagnosis of Cancer as an Emergency: A Critical Review of Current Evidence

Background: Many patients with cancer are diagnosed through an emergency presentation, which is associated with inferior clinical and patient-reported outcomes compared with those of patients who are diagnosed electively or through screening. Reducing the proportion of patients with cancer who are diagnosed as emergencies is, therefore, desirable; however, the optimal means of achieving this aim are uncertain owing to the involvement of different tumor, patient and health-care factors, often in combination. Methods: We searched the literature to identify all population-based studies that examined emergency presentation as a diagnosis or independent variable. Results: Most relevant evidence relates to patients with colorectal or lung cancer in a few economically developed countries, and defines emergency presentations contextually (that is, whether patients presented to emergency health-care services and/or received emergency treatment shortly before their diagnosis) as opposed to clinically (whether patients presented with life-threatening manifestations of their cancer). Consistent inequalities in the risk of emergency presentations by patient characteristics and cancer type have been described, but limited evidence is available on whether, and how, such presentations can be prevented. Evidence on patients' symptoms and health-care use before presentation as an emergency is sparse. Conclusion: In this review, we describe the extent, causes and implications of a diagnosis of cancer following an emergency presentation, and provide recommendations for public health and health-care interventions, and research efforts aimed at addressing this underresearched aspect of cancer diagnosis.

Variation in 'Fast-Track' Referrals for Suspected Cancer by Patient Characteristic and Cancer Diagnosis: Evidence From 670,000 Patients With Cancers of 35 Different Sites

Background: In England, 'fast-track' (also known as 'two-week wait') general practitioner referrals for suspected cancer in symptomatic patients are used to shorten diagnostic intervals and are supported by clinical guidelines. However, the use of the fast-track pathway may vary for different patient groups. Methods:  We examined data from 669,220 patients with 35 cancers diagnosed 2006-2010 following either fast-track or nonfast track primary-to-secondary care referrals using a bespoke English dataset, the 'Routes to Diagnosis' data. We estimated the proportion of fast-track referrals by sociodemographic characteristics and cancer diagnosis and used logistic regression to estimate respective crude and adjusted odds ratios. We additionally explored whether sociodemographic associations varied by cancer. Results:  There were large variations in the odds of fast-track referral by cancer ( P < 0.001). Patients with testicular and breast cancer were most likely to have been diagnosed after a fast-track referral (adjusted odds ratios 2.73 and 2.35 respectively, using rectal cancer as reference); while patients with brain cancer and leukemias least likely (adjusted odds ratios 0.05 and 0.09 respectively for brain cancer and acute myeloid leukemia). There were sex, age and deprivation differences in the odds of fast-track referral ( P < 0.013), which varied in their size and direction for patients with different cancers ( P < 0.001). For example, fast-track referrals were least likely in younger women with endometrial cancer and in older men with testicular cancer. Conclusion: Fast-track referrals are less likely for cancers characterized by nonspecific presenting symptoms and patients belonging to low incidence demographic strata. Interventions beyond clinical guidelines for “alarm” symptoms are needed to improve diagnostic timeliness.

Common patterns of morbidity and multi-morbidity and their impact on health-related quality of life: evidence from a national survey

Background

There is limited evidence about the impact of specific patterns of multi-morbidity on health-related quality of life (HRQoL) from large samples of adult subjects.

Methods

We used data from the English General Practice Patient Survey 2011–2012. We defined multi-morbidity as the presence of two or more of 12 self-reported conditions or another (unspecified) long-term health problem. We investigated differences in HRQoL (EQ-5D scores) associated with combinations of these conditions after adjusting for age, gender, ethnicity, socio-economic deprivation and the presence of a recent illness or injury. Analyses were based on 831,537 responses from patients aged 18 years or older in 8,254 primary care practices in England.

Results

Of respondents, 23 % reported two or more chronic conditions (ranging from 7 % of those under 45 years of age to 51 % of those 65 years or older). Multi-morbidity was more common among women, White individuals and respondents from socio-economically deprived areas. Neurological problems, mental health problems, arthritis and long-term back problem were associated with the greatest HRQoL deficits. The presence of three or more conditions was commonly associated with greater reduction in quality of life than that implied by the sum of the differences associated with the individual conditions. The decline in quality of life associated with an additional condition in people with two and three physical conditions was less for older people than for younger people. Multi-morbidity was associated with a substantially worse HRQoL in diabetes than in other long-term conditions. With the exception of neurological conditions, the presence of a comorbid mental health problem had a more adverse effect on HRQoL than any single comorbid physical condition.

Conclusion

Patients with multi-morbid diabetes, arthritis, neurological, or long-term mental health problems have significantly lower quality of life than other people. People with long-term health conditions require integrated mental and physical healthcare services.

Electronic supplementary material

The online version of this article (doi:10.1007/s11136-014-0820-7) contains supplementary material, which is available to authorized users.

Simultaneous quantification of verbenalin and verbascoside in Verbena officinalis by ATR-IR and NIR spectroscopy

Attenuated-total-reflectance infrared spectroscopy (ATR-IR) and near-infrared diffuse reflectance spectroscopy (NIR) in hyphenation with multivariate analysis was utilized to quantify verbenalin and verbascoside in Verbena officinalis. A new high performance liquid chromatography (HPLC) method as a reference was established and validated. For both vibrational spectroscopic methods test-set and cross validation were performed. Different data-pre-treatments like SNV, 1st and 2nd derivative were applied to remove systematic errors and were evaluated. Quality parameters obtained for the test-set validation revealed that ATR-IR (verbenalin: R(2)=0.94, RPD=4.23; verbascoside: R(2)=0.93, RPD=3.63) has advantages over NIR (verbenalin: R(2)=0.91, RPD=3.75; verbascoside: R(2)=0.80, RPD=2.35) in the given application.

Use of Chromatographic (SPE-HPLC) and Spectrophotometric Methods for Differentiation of Salix Species Through Correlation Analysis and FreeViz Projection

The major concern of the present article is research into the combination of analytical assessment and multi-correlative data interpretation. For this purpose, a high performance liquid chromatography (HPLC) procedure was developed for the simultaneous quantification of salicin, salicylalcohol derivatives, phenolic acids, flavonoids, and monomeric catechins after solid phase extraction (SPE). On the basis of an established and validated HPLC method, 49 different Salix samples were extracted, purified, and analysed. Furthermore, the quantity of total polyphenols (Folin-Ciocalteau colorimetric reaction) and the antioxidant activity (DPPH radical scavenging activity test) were determined and correlated. This yielded correlation coefficients at P-values less than 0.05 of 0.775, 0.967, 0.932, and 0.989 for Salix fragilis, Salix rubens, Salix purpurea (2006), and Salix purpurea (2007), respectively. Correlation with mean values of each species between total polyphenols content and % DPPH inhibition values occurred at a correlation coefficient (r) of 0.851. Linear correlations of quantified HPLC data with DPPH data and with total polyphenols content could also be found for salicin, gentisic acid, naringin, and salicylic acid. Finally, by combining HPLC data with total polyphenols content and antioxidant capacity through 3-D scatter plots and FreeViz data projection, it was shown that primarily the amount of epicatechin and saligenin beside DPPH values and total polyphenols content enable the classification into plant species and further by year of harvest.

Online system for temperature and accumulated dose control in plasma-based ion implantation

Surface treatment optimization requires the control of the ion dose and the workpiece temperature, two parameters that are not trivially measurable in plasma-based ion implantation. A temperature and ion fluence monitoring system has been developed and implemented in a plasma-based ion implanter. It is based on the measurement with a thermopile of the radiation emitted from the back face of a thin copper disk inserted in the stainless steel sample holder. Since the incident ions carry practically all the incident power, the measurement of the Cu disk temperature that increases during implantation can provide an evaluation of the ion fluence in real time. A model has been developed for the deconvolution of the temperature data and has been fitted to the temperature behavior during implantation. A good agreement between the total integrated doses, evaluated with Rutherford backscattering spectroscopy characterization, and the ion fluence calculated by means of this model has been obtained with a discrepancy less than 16%.

Comparative analysis of naphthodianthrone and phloroglucine derivatives in St. John's Wort extracts by near infrared spectroscopy, high-performance liquid chromatography and capillary electrophoresis

A near infrared spectroscopic (NIRS) method is established for quantitative determination of naphthodianthrones and phloroglucine derivatives in St. John's Wort extracts. The validated NIRS method is compared with optimised liquid chromatography (LC) and capillary electrophoresis (CE), applying UV as a detection tool. Optimisation of stationary and mobile phase conditions in reversed-phase liquid chromatography (RP-LC) allow separating the derivatives of interest with high peak symmetry and robustness. Elution takes 15 and 25 min on non-porous or porous silica C18 with different porosities, respectively. Capillary electrophoresis (CE) is used for cross-validation of RP-LC. CE enables baseline separation of hypericine and pseudohypericine in less than 2min, but is ten times less sensitive. The validated RP-LC is chosen as a reference method for calibration of the NIRS-system. Analysis of 80 St. John's Wort extracts (320 NIR spectra) and the subsequent chemometric calculations of the best regression model show that NIRS is suitable for analysis of hypericine, pseudohypericine and hyperforine. RP-LC or CE must be employed for the other remaining lower concentrated naphthodianthrone and phloroglucine derivatives. Hypericine and hyperforine are analysed via NIRS with a standard error of estimation (SEE) of 0.52 and 0.50 microg mL(-1) and standard error of prediction (SEP) of 0.64 and 0.71 microg mL(-1) within few seconds. The current study demonstrates the suitability of NIRS as an alternative to LC and CE for St. John's Wort producing phytopharmaceutical industry. The short analysis time of few seconds' assures high sample throughput in routine analysis.

Limitations and uses of gastrojejunal feeding tubes

BACKGROUND

Gastrostomy feeding is a well established alternative method to long term nasogastric tube feeding. Many such patients have gastro-oesophageal reflux (GOR) and require a fundoplication. A transgastric jejunal tube is an alternative when antireflux surgery fails, or is hazardous or inappropriate.

AIMS

To review experience of gastrojejunal (G-J) feeding over six years in two regional centres in the UK.

METHODS

Retrospective review of all children who underwent insertion of a G-J feeding tube.

RESULTS

There were 18 children, 12 of whom were neurologically impaired. G-J tubes were inserted at a median age of 3.1 years (range 0.6-14.7) because of persistent symptoms after Nissen fundoplication (n = 8) or symptomatic GOR where fundoplication was inappropriate. Four underwent primary endoscopic insertion of the G-J tube; the remainder had the tube inserted via a previous gastrostomy track. Seventeen showed good weight gain. There was one insertion related complication. During a median follow up of 10 months (range 1-60), four experienced recurrent aspiration, bilious aspirates, and/or diarrhoea. There were 65 tube related complications in 14 patients, necessitating change of the tube at a median of 74 days. Jejunal tube migration was the commonest problem. Five died from complications of their underlying disease.

CONCLUSIONS

Although G-J feeding tubes were inserted safely and improved nutritional status, their use was associated with a high rate of morbidity. Surgical alternatives such as an Roux-en-Y jejunostomy may be preferable.

Race-ethnic disparities in the impact of stroke risk factors: the northern Manhattan stroke study

BACKGROUND AND PURPOSE

Stroke risk factors have been determined in large part through epidemiological studies in white cohorts; as a result, race-ethnic disparities in stroke incidence and mortality rates remained unexplained. The aim in the present study was to compare the prevalence, OR, and etiological fraction (EF) of stroke risk factors among white, blacks, and Caribbean Hispanics living in the same urban community of northern Manhattan.

METHODS

In this population-based incident case-control study, cases (n=688) of first ischemic stroke were prospectively matched 1:2 by age, sex, and race-ethnicity with community controls (n=1156). Risk factors were determined through in-person assessment. Conditional logistic regression was used to calculate adjusted ORs in each race-ethnic group. Prevalence and multivariate EFs were determined in each race-ethnic group.

RESULTS

Hypertension was an independent risk factor for whites (OR 1.8, EF 25%), blacks (OR 2.0, EF 37%), and Caribbean Hispanics (OR 2.1, EF 32%), but greater prevalence led to elevated EFs among blacks and Caribbean Hispanics. Greater prevalence rates of diabetes increased stroke risk in blacks (OR 1.8, EF 14%) and Caribbean Hispanics (OR 2.1 P<0.05, EF 10%) compared with whites (OR 1.0, EF 0%), whereas atrial fibrillation had a greater prevalence and EF for whites (OR 4.4, EF 20%) compared with blacks (OR 1.7, EF 3%) and Caribbean Hispanics (OR 3.0, EF 2%). Coronary artery disease was most important for whites (OR 1.3, EF 16%), followed by Caribbean Hispanics (OR 1.5, EF 6%) and then blacks (OR 1.1, EF 2%). Prevalence of physical inactivity was greater in Caribbean Hispanics, but an elevated EF was found in all groups.

CONCLUSIONS

The prevalence, OR, and EF for stroke risk factors vary by race-ethnicity. These differences are crucial to the etiology of stroke, as well as to the design and implementation of stroke prevention programs.

A 'segmented' sex industry in New Zealand: sexual and personal safety of female sex workers

OBJECTIVE

Assess differences in personal circumstances, risk exposure and risk-taking among female sex workers in different sectors of the New Zealand sex industry in regard to issues of sexual safety, drug use, violence and coercion.

METHOD

A cross-sectional survey of 303 female sex workers was carried out in Christchurch, New Zealand, May-September 1999.

RESULTS

There was evidence of 'segmentation': street workers were younger, had started work at a younger age and had less education than indoor workers. More street than indoor workers used money from sex work for drugs and used drugs at work. There was a high level of condom use but little 'negotiation' about them with clients. High levels of violent experiences were reported, but street workers reported more, and more extreme forms of, violence than indoor workers.

IMPLICATIONS

Although knowledge of condom use and sexual safety appears generally high and women in both sectors report taking the initiative for safer sex, drug use, violence and coercion remain of concern. While sexual safety will need ongoing health promotion and education interventions to support and ensure the uptake of safer sex practice by new workers and prevent any relapse by more experienced workers, issues of violence and coercion also require attention to the power relationships between individuals. Legislation and policy directed at these issues should encourage the control women can exert over their work practice. Reducing exposure to personal risk may require different measures in different sectors.

Flow cytometric analysis of lymphocyte subpopulations in bronchoalveolar lavage fluid after repeated ozone exposure

As known from studies in animal and human subjects, ozone can exert effects on the immune response including allergic sensitisation and allergen responsiveness. The objective of the present study was to assess the changes in lymphocyte subsets in bronchoalveolar lavage fluid (BALF) after single and repeated ozone exposures. Twenty-three healthy subjects underwent single exposures to 200 ppb ozone or filtered air (FA), as well as repeated exposures to 200 ppb ozone on four consecutive days, each during 4 h of intermittent exercise. Bronchoalveolar lavage was performed 20 h after the single exposure or the last of the repeated exposures. Lymphocytes were identified by sideward scatter and CD45 expression, and their subsets by eight different panels of antibodies. Checksums were calculated to assess the validity of the results. The percentage and the absolute number of lymphocytes, mostly comprising T-lymphocytes (CD2+; overall mean 98.8%), increased after single (P < 0.05; each), but not after repeated ozone exposure, compared with FA (7.4 vs 5.8 vs 6.5%; 680 vs 419 vs 301 x 10(3)). In addition, we observed small but statistically significant changes in the proportions of lymphocyte subpopulations. The percentage of CD4+ lymphocytes increased after single (P < 0.05) and repeated ozone exposure (P < 0.01), whereas the percentage of CD8+ cells decreased after repeated exposure (P < 0.05). The proportion of activated lymphocytes (CD25+) was elevated after repeated, compared with single, ozone exposure (P < 0.01), and the percentages of natural killer (NK) cells were decreased after both single (P < 0.05) and repeated (P < 0.01) exposures. Our data suggest that single but not repeated ozone exposures cause a change in absolute numbers of lymphocytes in BALF, whereas the proportions of lymphocyte subsets are affected by single as well as repeated exposures.

Services and information utilised by female sex workers for sexual and physical safety

AIMS

To examine services utilised by female sex workers in Christchurch for sexual and physical safety.

METHOD

Estimates were made of the sex worker population in Christchurch before conducting a cross-sectional survey.

RESULTS

303 women responded. Almost all went for sexual health check-ups. Most (251) had a general practitioner, but only about half disclosed they were sex workers. Of the 135 women who used their own general practitioner for sexual health checks, 62% disclosed they were sex workers. In general, the women relied upon informal networks for information and advice, but the peer organisation of New Zealand Prostitutes Collective was also important.

CONCLUSION

While general practitioners were used by the majority of sex workers, high levels of nondisclosure need to be understood and redressed. The preference of sex workers for informal, peer relationships should be considered in future health promotion efforts.

Management of septicaemic infants during long-term parenteral nutrition

Young infants, particularly following gastrointestinal surgery, are at high risk of septicaemia during parenteral nutrition. Febrile illness in the absence of focal infection inevitably raises suspicion of central venous catheter sepsis and poses the following dilemma: remove the catheter (which may then prove uninfected) and lose venous access, or leave the catheter and risk clinical deterioration? We examined retrospectively the isolates from blood culture during febrile episodes in 13 children who received long-term (> 2 months) parenteral nutrition via a central venous catheter, and assessed the effectiveness of through-catheter antibiotic treatment during 76 episodes of blood culture positive sepsis. Coagulase-negative Staphylococci accounted for only 16% of positive isolates, with yeasts accounting for 5%, and Gram-negative organisms accounting for 46%, suggesting that infection was often associated with bacterial translocation from the gastrointestinal tract. Treatment with the central venous catheter left in situ was successful in resolving infection in 53 (70%) of septic episodes. These findings indicate that, in this specific group of patients, through-catheter antibiotic treatment is often effective in treating septicaemia. When long-term venous access is essential, this approach should be tried before recourse to central venous catheter removal.

Children with neurological disorders do not always need fundoplication concomitant with percutaneous endoscopic gastrostomy

Whether antireflux surgery should be routinely performed at the time of gastrostomy in children with neurological disorders is debatable because of the risk of gastroesophageal reflux. Some argue that these children should be screened for occult gastroesophageal reflux as this will determine the need for fundoplication. This study retrospectively examines outcome in 29 children with neurological disorders who underwent percutaneous endoscopic gastrostomy (PEG) without concomitant fundoplication. Children were included if they had no clinical evidence of severe gastroesophageal reflux before PEG insertion. The median age of children at PEG insertion was 5.6 years (range 1.1 to 18.0). The children were followed for a median of 2.6 years (range 0.4 to 4.9). Insertion of PEG was technically impossible in two children; and an asymptomatic gastrocolic fistula in another child led to subsequent tube removal. Fourteen of the 26 remaining children developed symptomatic gastroesophageal reflux after PEG; five of these showed no reflux on pH monitoring prePEG. Control of symptoms was achieved by medical intervention in 12, but two required fundoplication. Our findings indicate that in the child with neurological disabilities without symptoms indicating severe gastroesophageal reflux, fundoplication is unlikely to be necessary as a consequence of PEG insertion. We conclude that routine investigation for gastroesophageal reflux in the child without severe vomiting can be avoided and the number of antireflux procedures reduced.

Hepatitis C virus and other flaviviridae viruses enter cells via low density lipoprotein receptor

Endocytosis of the Flaviviridae viruses, hepatitis C virus, GB virus C/hepatitis G virus, and bovine viral diarrheal virus (BVDV) was shown to be mediated by low density lipoprotein (LDL) receptors on cultured cells by several lines of evidence: by the demonstration that endocytosis of these virus correlated with LDL receptor activity, by complete inhibition of detectable endocytosis by anti-LDL receptor antibody, by inhibition with anti-apolipoprotein E and -apolipoprotein B antibodies, by chemical methods abrogating lipoprotein/LDL receptor interactions, and by inhibition with the endocytosis inhibitor phenylarsine oxide. Confirmatory evidence was provided by the lack of detectable LDL receptor on cells known to be resistant to BVDV infection. Endocytosis via the LDL receptor was shown to be mediated by complexing of the virus to very low density lipoprotein or LDL but not high density lipoprotein. Studies using LDL receptor-deficient cells or a cytolytic BVDV system indicated that the LDL receptor may be the main but not exclusive means of cell entry of these viruses. Studies on other types of viruses indicated that this mechanism may not be exclusive to Flaviviridae but may be used by viruses that associate with lipoprotein in the blood. These findings provide evidence that the family of LDL receptors may serve as viral receptors.

A competitive reverse transcription-polymerase chain reaction assay for quantitation of GB virus C/hepatitis G virus RNA that circumvents heteroduplex artifact

The role of GB virus C (GBV-C)/hepatitis G virus (HGV) in hepatitis has been controversial. To investigate its possible pathogenicity and site(s) of replication, it is important to develop an accurate quantitative assay for both positive and negative strand GBV-C/HGV RNA. In this study, a competitive reverse transcription-polymerase chain reaction (RT-PCR) assay for both positive and negative strand GBV-C/HGV RNA quantitation was developed. In developing the quantitative assay, heteroduplex formation was repeatedly observed. A heterologous competitor RNA with GBV-C/HGV primer-binding sequences was introduced, and heteroduplex artifact was circumvented successfully. Two-hundred thirty-seven serum specimens were screened by RT-PCR for GBV-C/HGV RNA. Two of the 62 patients infected with chronic hepatitis C virus (HCV) were found to be positive for GBV-C/HGV RNA. None of the 50 other patients with no evidence of HCV infection and none of the 125 normal individuals were positive for GBV-C/HGV RNA. The sensitivity of RT-PCR was 3000 gE/ml (30 gE in RT-PCR). Alternate methods for residual DNA removal and its detection in synthetic RNA were introduced. A RT control containing no primer before PCR is necessary to evaluate the trace amounts of template DNA remaining in synthesized RNA. The method will differentiate reliably between positive and negative strand RNAs up to a 10(4)-fold difference in titer. The positive and negative strand GBV-C/HGV RNAs were detected in one patient by RT-PCR and hybridization analysis, and the strand titer was determined by RT-PCR.

Limited ileal resection in infancy: the long-term consequences

BACKGROUND/PURPOSE

The longer-term sequelae of short bowel syndrome in infancy are reasonably well documented, but little is known about the long-term nutritional and metabolic effects of limited (less than 50 cm) ileal resection. This makes it difficult to formulate a rational follow-up policy in such children.

METHODS

All children who underwent limited ileal resection for either necrotizing enterocolitis (NEC) or intussusception at our institution between 1984 and 1992 were invited to attend a detailed clinical, anthropometric, hematologic, and biochemical assessment, together with a biliary and renal ultrasound scan and measurement of bone mineral density.

RESULTS

Twenty-four children (NEC, 17; intussusception, 7) of median age 7.4 years (range, 5.5 to 13.7 years) agreed to participate. Nine previously had undergone an isolated ileal resection, and 15 also had had variable lengths of colon removed. The length of resected ileum ranged from 3 to 44 cm, with a median of 10 cm. Seven control subjects in whom neonatal NEC developed but recovered without surgery were also evaluated. Median height, weight, and body mass index after ileal resection were between the 25th and 50th percentiles; no child was stunted or wasted. After ileal resection, one boy was found to have asymptomatic vitamin B12 deficiency, and three children had low plasma concentrations of vitamin A. Hematologic and biochemical parameters were otherwise normal apart from a few marginally low trace element levels in both subjects and controls. No renal calculi were detected, and bone mineral density measurements were normal in all except one child. Four children had cholelithiasis, all of whom had previously undergone limited ileal resection for NEC (two isolated, two ileocolic). Thus, the prevalence of cholelithasis after limited ileal resection for NEC was 24% at a median age of 7.0 years.

CONCLUSIONS

Growth and nutritional status are well preserved after limited ileal resection in infancy. Limited ileal resection for NEC is associated with a subsequent high prevalence of cholelithiasis and a risk of vitamin B12 deficiency. These findings are important when planning strategies for long-term follow-up.

Detection of widespread hepatocyte infection in chronic hepatitis C

The controversial question of the extent of hepatocyte infection in chronic hepatitis C was re-examined in both chimpanzees and humans using a newly modified in situ hybridization (ISH) method for detecting hepatitis C virus (HCV) RNA. The specificity of the methodology for distinguishing positive- and negative-strand synthetic HCV RNA was at least six magnitudes greater than the reverse-transcription polymerase chain reaction (RT-PCR) assay for HCV. The sensitivity of the methodology as determined by cell culture assay was 14 +/- 2 genomic equivalents (gE) of HCV positive strand per cell, which was three magnitudes less sensitive than RT-PCR quantitation of HCV. In contrast to previous studies in both humans and chimpanzees with chronic hepatitis C, a high percentage of hepatocytes positive for both positive- and negative-strand HCV RNA was found in most specimens studied. In humans, the extent of hepatocyte infection varied with histological activity index (HAI). In the two chimpanzees studied, the liver biopsies showed minimal histological disease activity, but high percentages of hepatocytes were HCV-positive by ISH that correlated with hepatocyte ultrastructural changes associated with HCV infection. Hepatocyte infection was confirmed by RNA extraction and RT-PCR techniques for detecting HCV RNA that minimize the false detection of negative strands. In both human and chimpanzee liver biopsies showing minimal HAI, the hepatocyte concentration of HCV was estimated to be very low. These findings suggested the hypothesis that persistent infection in the liver may be caused in part by low-level HCV replication. The theoretical and clinical implications of these findings are discussed.

Localization of hepatitis C virus in cutaneous vasculitic lesions in patients with type II cryoglobulinemia

OBJECTIVE

To investigate the role of hepatitis C virus (HCV) in the pathogenesis of the cutaneous vasculitis in patients with type II cryoglobulinemia.

METHODS

Using in situ hybridization detection of HCV, we studied 6 test patients and various control subjects. Serum HCV was quantitated, cryoglobulins were analyzed by column chromatography at 37 degrees C, and low-density lipoprotein (LDL) receptors on keratinocytes were detected using LDL labeled with fluorescent dye.

RESULTS

In the cutaneous vasculitic lesions from test patients, but not control subjects, the HCV virion was found in association with IgM and IgG. HCV alone was detected in some vessel walls, and in skin and ductal epithelium and vascular endothelium in inflamed, but not normal, skin. Cryoglobulins showed HCV, monomeric IgM, and monomeric IgG, with little or no immune complexes. The extent of the lesions correlated with levels of viremia. Up-regulation of LDL receptors on keratinocytes was detected in inflamed, but not normal, skin.

CONCLUSION

HCV was present in the cutaneous vasculitic lesions, most likely in complexes with IgM and IgG formed in situ. These findings and the correlation of the severity of the rash with the level of viremia suggest that HCV plays a major role in the pathogenesis of cutaneous vasculitis in these patients and strengthens the rationale for antiviral drug therapy. The presence of HCV in keratinocytes and ductal epithelial and vascular endothelial cells may be the in vivo manifestation of endocytosis of HCV by the LDL receptors that has recently been demonstrated in vitro. The up-regulation of LDL receptors on keratinocytes in inflamed skin is consistent with this postulation.

The association of hepatitis C virus infection with monoclonal rheumatoid factors bearing the WA cross-idiotype: implications for the etiopathogenesis and therapy of mixed cryoglobulinemia

OBJECTIVE

To determine the prevalence of monoclonal rheumatoid factors (mRF) bearing the WA cross-idiotype (WA XId) in hepatitis C virus (HCV) positive type II mixed cryoglobulins, to review recent studies on the role of HCV in the cutaneous vasculitis lesions in patients with type II cryoglobulinemia and to discuss the implication of these studies for the etiopathogenesis and therapy of the disease.

METHODS

Thirty type II cryoglobulins were tested for WA and PO XId and for HCV RNA:

RESULTS

WA mRF were strongly, although not exclusively, associated with HCV in type II mixed cryoglobulinemia.

CONCLUSION

These and other recent studies from our laboratory suggest that chronic HCV infection may be the stimulus for the production of WA mRF and that HCV may be directly involved in the pathogenesis of the cutaneous vasculitis in patients with type II cryoglobulinemia. The association of HCV infection with the disease provides a rationale for anti-viral therapy and for monitoring therapy by measuring the HCV level in both blood and liver.

Organ-specific differences in the ratio of alternatively spliced chorismate synthase (LeCS2) transcripts in tomato

The primary transcript of one of the two chorismate synthase genes (LeCS2) of tomato is differentially processed due to an alternative splicing of the third intron. A novel observation was made when the abundances of the two LeCS2-specific transcripts in different organs were analysed. The ratio of these two transcripts differs in RNA populations from different organs. Possible explanations for this finding and its potential physiological impact for plant metabolism are discussed.

Mechanism of action of an orally administered platinum complex [ammine bis butyrato cyclohexylamine dichloroplatinum (IV) (JM221)] in intrinsically cisplatin-resistant human ovarian carcinoma in vitro

Intrinsic resistance to existing clinical platinum drugs is a major cause of treatment failure; moreover, these agents have the drawbacks of cross-resistance and intravenous administration. The mechanism of intrinsic cisplatin resistance and the mechanism of circumvention of intrinsic resistance by a member (JM221) of the ammine/amine platinum (IV) dicarboxylate class of platinum complex was studied in intrinsically resistant (SKOV-3) and sensitive (41M) human ovarian carcinoma cell lines. JM221 reduced the cisplatin resistance factor nine- to 2.7-fold, was more potent than cisplatin and showed marked time-dependent cytotoxicity. Cellular platinum accumulation was 20- to 40-fold greater (P < 0.001), and DNA platination was fourfold greater (P < 0.02), immediately following 2 h equimolar exposure to JM221, compared with cisplatin. DNA platinum levels decreased following cisplatin exposure with a half-life approximating 48 h in both lines, while no net removal of DNA-bound platinum was recorded following JM221 exposure. JM221 caused DNA interstrand cross-linking, but this was 10-20% less frequent with JM221 than with cisplatin when expressed as a proportion of total DNA platinum lesions. Cisplatin DNA interstrand cross-linking was twofold greater in the intrinsically sensitive line (41M) than in the resistant line (SKOV-3) over a range of concentrations and time-points. Neither cellular platinum accumulation, levels of DNA platination nor the rate of removal of DNA-bound platinum in the two cell lines related to their ninefold difference in cisplatin sensitivity. Intrinsic cisplatin resistance appears to be attributable to the inhibition of formation of bifunctional DNA lesions, while the circumvention of intrinsic resistance by JM221 seems to be the result of both improved transport properties and circumvention of DNA repair mechanisms.

Synthesis and cytotoxicity of potential tumor-inhibitory analogues of trimelamol (2,4,6-tris[(hydroxymethyl)methylamino]-1,3,5-triazine) having electron-withdrawing groups in place of methyl

In exploring the structural features which determine the antitumor activity of 2,4,6-tris-[(hydroxymethyl)methylamino]-1,3,5-triazine (trimelamol, 1), we have synthesized analogues in which the methyl groups have been replaced by the electron-withdrawing substituents 2,2,2-trifluoroethyl (5), propargyl (13), and cyanomethyl (15) via the respective tris(alkylamino)triazines 3, 12, and 14. Three mono[(hydroxymethyl)amino]triazines (4, 7, and 10) were also prepared. All the new tris(hydroxymethyl) derivatives showed cytotoxicities toward a variety of experimental rodent and human ovarian tumor cell lines similar to those shown by 1, the cyanomethyl analogue (15) having the most favorable profile. Mono(hydroxymethyl) derivatives (4 and 7) were ca. one-third as toxic. The new tris(hydroxymethyl) analogues were more stable to aqueous hydrolysis than was 1. Half-life (pH 7.5) values were, for 1, 120 min, for 5, 690 min, for 13, 450 min, and for 15, 275 min, but at pH 2.0, 15 (t1/2 350 min) was the most stable. This cyanomethyl analogue was also the most water-soluble, being comparable to 1 whereas 5 and 13 were poorly soluble.

Histidine2 of the alpha-factor of Saccharomyces cerevisiae is not essential for binding to its receptor or for biological activity

Seven His2 analogs of the Saccharomyces cerevisiae [Nle12]alpha-factor, WXWLQLKPGQP(Nle)Y, where X = beta-D-thienylalanine, beta-L-thienylalanine, 1-D-methylhistidine, 1-L-methylhistidine, 3-D-methylhistidine, 3-L-methylhistidine, and beta-3-L-pyridylalanine, were synthesized and purified to homogeneity. Assays were carried out on binding to the alpha-factor receptor and of biological activity determined by either growth arrest or morphological changes in target cells. In the L-isomer, replacement of the imidazole of histidine by thiophene or 3-pyridyl groups or derivatization of either nitrogen of the imidazole ring by methylation resulted in a 2-100-fold decrease in bioactivity. D-Isomers of the beta-thienylalanyl-, 1-methylhistidinyl-, or 3-methylhistidinyl-alpha-factors did not possess measurable bioactivity with the exception of comparatively low activity of the 3-D-methylhistidinyl and 1-D-methylhistidinyl-alpha-factors in the morphogenesis assay. In contrast, both active and inactive analogs demonstrated binding affinities 10-20-fold less than that of [Nle12]alpha-factor. These results indicate that the histidine residue of alpha-factor is not required for binding to the receptor or for biological activity and that bioactivity and binding can be dissociated through the use of pheromone analogs.

Preclinical antitumor evaluation of bis-acetato-ammine-dichloro-cyclohexylamine platinum(IV): an orally active platinum drug

The cytotoxicity of a novel platinum(IV) complex, bis-acetato-amminedichloro-cyclohexylamine platinum(IV) (JM216), has been evaluated in vitro against a panel of human tumor cell lines (predominantly ovarian) representative of models of intrinsic and acquired to cisplatin. In addition, the activity of JM216 administered by the p.o. route has been determined in vivo using the murine ADJ/PC6 plasmacytoma and four human ovarian carcinoma xenograft lines. In vitro, against seven human ovarian carcinoma cell lines, JM216 showed similar cytotoxicity and pattern of cytotoxicity to cisplatin (mean 50% inhibitory concentrations of 3.5 microM for cisplatin and 1.7 microM for JM216). The cytotoxicity of JM216 was more dependent on the time of drug exposure than that of cisplatin, suggesting that extended split-dosing rather than a single bolus administration might be a more appropriate schedule in patients. Using six pairs of acquired cisplatin-resistant and parent human tumor cell lines (four ovarian, one testicular, and one cervical) JM216 exhibited non-cross-resistance (resistance factor of < 1.5) in three whereas tetraplatin exhibited partial or full cross-resistance in all six pairs. Notably, in two of the acquired cisplatin-resistant lines (41McisR and HX/155cisR) where JM216 retained activity, resistance has previously shown to be due primarily to reduced platinum uptake. In vivo, following p.o. administration using the cisplatin-sensitive murine ADJ/PC6 plasmacytoma, JM216 showed antitumor selectivity far superior to that observed for either cisplatin, carboplatin, or tetraplatin. Across four human ovarian carcinoma xenografts of widely differing sensitivity to cisplatin and carboplatin, JM216 exhibited p.o. activity, broadly comparable to that observed for i.v. administered cisplatin and carboplatin and markedly superior to i.p. administered tetraplatin. These antitumor properties suggest that JM216 provides a structural lead to platinum complexes which may circumvent transport-determined acquired resistance to cisplatin and is a suitable candidate as an p.o. administrable platinum complex for phase I clinical trial.

Reduced drug accumulation as a major mechanism of acquired resistance to cisplatin in a human ovarian carcinoma cell line: circumvention studies using novel platinum (II) and (IV) ammine/amine complexes

Acquired resistance to cisplatin (cis-diamminedichloroplatinum (II)) has been generated in vitro in the 41M human ovarian carcinoma cell line, established from a previously untreated patient. Three cisplatin-resistant variants were selected at approximately 2, 4 and 6-fold resistance (in terms of 50% inhibitory concentrations), in order to study the underlying mechanisms of acquired cisplatin resistance. Compared to the parent line, platinum accumulation following exposure to equimolar concentrations of cisplatin was on average (across the entire concentration range) 2.9, 3.6 and 4.8-fold lower in the 41McisR2, 41McisR4 and 41McisR6 cell lines, respectively. Thus the difference in uptake corresponded closely with their resistance factor in the three resistant variants. Moreover, a significant reduction in platinum accumulation was observed as early as 5 min after exposure to cisplatin in the 41M vs 41McisR6 cell lines. Platinum accumulation was similar in all cell lines following exposure to equitoxic concentrations (2 h IC50) of cisplatin. Enhanced efflux of drug was not observed between the 41M and 41McisR6 cells. In addition, there was no difference in intracellular glutathione (GSH) levels. Our previous studies have shown no indication of metallothionein involvement and the decrease in cisplatin uptake in the 41McisR6 cells was reflected by a similar reduction in DNA interstrand cross-links (ISC) formation. These results suggest that the mechanism of acquired resistance to cisplatin in the 41McisR6 cell line may be predominantly due to reduced drug uptake. The 41McisR6 cells were not found to be cross-resistant to ouabain, a postulated specific inhibitor of sodium-potassium adenosine triphosphatase (Na+, K(+)-ATPase), suggesting that decreased cisplatin accumulation in these cells is probably not regulated by alterations in their Na+, K(+)-ATPase levels, and Na+ potential across the plasma membrane. Cellular accumulation of a novel class of platinum (IV) ammine/cyclohexylamine dicarboxylates, which exhibit enhanced cytotoxicity over cisplatin and completely circumvent resistance to cisplatin in the 41McisR line, was also examined. The data suggests that increased accumulation of these compounds, as a result of their enhanced lipophilicity, could account for the dramatic increase in their potency over cisplatin.

Comparison of cellular accumulation and cytotoxicity of cisplatin with that of tetraplatin and amminedibutyratodichloro(cyclohexylamine)platinum(IV) (JM221) in human ovarian carcinoma cell lines

We have compared the cellular accumulation and cytotoxicity of three platinum compounds in a panel of five human ovarian carcinoma cell lines. The cell lines, which were established from both untreated and pretreated patients, showed a wide range in sensitivity to cisplatin and other platinum drugs. The panel consisted of two sensitive (41M, CH1), one in vivo acquired resistant (PXN/94) with moderate sensitivity, and two intrinsically resistant (SKOV-3, HX/62) cell lines. The cisplatin 2-h concentration of drug required to inhibit cell growth by 50% compared with vehicle treated control cells (IC50 values) for these cell lines were in the following order: CH1 < 41M < PXN/94 < SKOV-3 < HX/62. None of the cell lines showed saturation of platinum accumulation (per mg protein) at 2 h after exposure to cisplatin concentrations of up to 500 microM. The highest cellular platinum accumulation was observed in the sensitive 41M cell line which was established from an untreated patient. The lowest accumulation was found in the intrinsically resistant HX/62 cell line. The rate of platinum accumulation at an equimolar concentration of cisplatin was 41M > SKOV-3 > CH1 > PXN/94 > HX/62. The relationship between drug accumulation and cytotoxicity was evaluated by comparing 2-h IC50 values with platinum accumulation following exposure to both equimolar and equitoxic doses of the agent. The results suggest that reduced drug accumulation may play a partial role in the mechanism of intrinsic resistance to cisplatin in one cell line (SKOV-3) and a major role in another (HX/62), where reduced accumulation is attributable to reduced uptake rather than enhanced efflux. Decreased drug accumulation may also contribute significantly to the lower sensitivity of the PXN/94 cell line to cisplatin. Interestingly, both the PXN/94 and the sensitive CH1 cell lines, which were established from patients pretreated with platinum drugs, showed reduced drug accumulation relative to the 41M cell line. Cellular accumulation of tetraplatin and JM221 [(ammine)dibutyratodichloro(cyclohexylamine)platinum(IV)], a novel platinum(IV) dicarboxylate complex exhibiting enhanced cytotoxicity compared to cisplatin, was also examined. Comparison with platinum accumulation from cisplatin suggests that the increased cytotoxicity of tetraplatin and JM221 may be related to their increased accumulation. Significantly both agents are more lipophilic than cisplatin, which may account partially for their improved uptake in cisplatin resistant cells.

Stimulation of human monocyte beta-glucan receptors by glucan particles induces production of TNF-alpha and IL-1 beta

beta-glucans are pharmacologic agents that rapidly enhance host resistance to a variety of biologic insults through mechanisms involving macrophage activation. To determine whether stimulation of the beta-glucan receptors on human monocytes resulted in cytokine production, monolayers of monocytes were incubated with purified yeast glucan particles and measured for tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta) mRNA and protein. By Northern blot analysis, TNF-alpha mRNA was detected within 30 min of incubation with glucan particles, peaked at 2 h, and remained elevated for at least 8 h. Glucan induction of IL-1 beta mRNA followed a similar time-course of initiation and accumulation. By enzyme-linked immunosorbent assays (ELISAs), significant levels of TNF-alpha and IL-1 beta were present in supernatants of glucan-treated cells within 1 h and plateau levels of both cytokines were approached within 4 h. At particle-to-cell ratios of from 0.4 to 18, glucan particles induced dose-dependent increases in TNF-alpha and IL-1 beta mRNA and corresponding increases in TNF-alpha and IL-1 beta proteins. Exposure of monocytes to glucan particles for 0-30 min and washing before continued incubation for 4 h in particle-free buffer induced production and secretion of TNF-alpha and IL-1 beta in a time-dependent fashion compatible with phagocytosis. The pretreatment of monocyte monolayers with trypsin reduced glucan-induced production of TNF-alpha and IL-1 beta in a dose-dependent manner with 5 micrograms/ml of trypsin effecting reductions of greater than 50%. Thus, glucan particles induce human monocyte production of TNF-alpha and IL-1 beta by a mechanism that is dependent on trypsin-sensitive beta-glucan receptors.

Mechanism-related circumvention of acquired cis-diamminedichloroplatinum(II) resistance using two pairs of human ovarian carcinoma cell lines by ammine/amine platinum(IV) dicarboxylates

Acquired resistance to cisplatin has been generated in vitro in two human ovarian carcinoma cell lines: 41M, established from a previously untreated patient; and CH1, from a patient previously treated with cisplatin and cis-diammine-1,1-cyclobutane dicarboxylatoplatinum(II) (carboplatin). In neither cell line with acquired resistance did intracellular detoxification (via increased glutathione or metallothioneins) appear to be a major determinant of resistance. Resistance in 41McisR (resistance factor of 4.7) appeared to be due predominantly to a reduced platinum accumulation (levels were only 23.8% in 41McisR versus 41M). This was also reflected at the DNA level by a similar level of reduced DNA interstrand cross-links and total platinum-DNA adducts measured immediately after a 2-h exposure to cisplatin in 41McisR versus 41M. Conversely, for CH1cisR (resistance factor of 6.5), platinum accumulation, and initial numbers of DNA-interstrand cross-links and total DNA-platinum adducts were not significantly different from the parent CH1 line. This is suggestive of a resistance mechanism involving increased DNA repair or tolerance to platinum-DNA adducts operating in the CH1cisR/CH1 pair of lines. Cross-resistance to carboplatin and partial cross-resistance to the 1,2-diaminocyclohexane-containing agent, (trans-d,l)-1,2-diaminocyclohexane tetrachloroplatinum(IV) (tetraplatin), was observed in both pairs. However, two novel platinum(IV) ammine/amine dicarboxylates, ammine dibutyratodichloro(cyclohexylamine)platinum(IV) (JM221) and ammine dibenzoatodichloro(propylamine)platinum(IV) (JM244), completely circumvented resistance in 41McisR to produce some collateral sensitivity (resistance factors of 0.67 and 0.54, respectively) but showed cross-resistance in CH1cisR (resistance factors of 3.7 and 4.6). In contrast to the data for cisplatin, intracellular platinum levels were not significantly different between the 41M and 41McisR pair of cell lines after exposure to JM244. These results suggest that the ammine/amine platinum(IV) dicarboxylates, which show considerably greater in vitro cytotoxicity than cisplatin, are capable of circumventing acquired cisplatin resistance which is due to decreased intracellular accumulation but are not able to overcome resistance at the level of DNA platination and removal.

Establishment and characterization of an in vitro model of acquired resistance to cisplatin in a human testicular nonseminomatous germ cell line

Clinically, human testicular nonseminomatous germ cell tumors exhibit remarkable sensitivity to platinum-based chemotherapy. To define better the mechanistic basis for this unusual sensitivity, the biochemical determinants of platinum-induced cytotoxicity have been investigated in a human testicular tumor cell line (GCT27) established from a previously untreated patient and in an in vitro derived 5.6-fold cisplatin-resistant stable variant (GCT27cisR). Compared to 12 ovarian and 5 cervical human tumor cell lines, the parent GCT27 line was among the most sensitive to the cytotoxic effects of both cisplatin (dosage producing 50% inhibition, 0.2 microM) and carboplatin (dosage producing 50% inhibition, 2.9 microM), thus reflecting clinical data. A 4-day exposure sulforhodamine B-staining assay was used to determine that GCT27cisR was cross-resistant to carboplatin and iproplatin and the classical bifunctional alkylating agents melphalan and chlorambucil. Partial cross-resistance was observed to tetraplatin, methotrexate, and mitomycin C. No cross-resistance was observed to Adriamycin, etoposide, vinblastine, bleomycin, 1-beta-D-arabinofuranosylcytosine, and 5-fluorouracil. Intracellular cisplatin accumulation across the dose range 2.5-100 microM (for 2 h) was 1.6 +/- 0.39-fold (mean +/- SD) greater for the parent line. There was no significant difference in glutathione levels between the two lines. The acquired resistance line was 1.9-fold more resistant than the parent line to the cytotoxic effects of cadmium chloride. There was no significant difference between the two lines, however, in the total amounts of platinum bound to DNA after cisplatin exposure (25, 50, or 100 microM for 2 h). The removal of total platinum adducts from DNA was significantly faster for GCT27cisR compared to the parent line (half-times of removal, 32 and 67 h, respectively). These data suggest that the abnormal sensitivity of the parent testicular tumor cell line to platinum-containing anticancer drugs may be due predominantly to an inherent defect in the ability of these cells to remove platinum from their DNA. This defect is apparently lost in the acquired resistance counterpart. Reduced intracellular accumulation and increased cytoplasmic concentrations of metallothionein may also contribute, in part, to the acquisition of cisplatin resistance in this model.

Ammine/amine platinum(IV) dicarboxylates: a novel class of platinum complex exhibiting selective cytotoxicity to intrinsically cisplatin-resistant human ovarian carcinoma cell lines

Using a panel of six human ovarian carcinoma cell lines varying by two orders of magnitude in terms of cisplatin cytotoxicity, we have investigated the in vitro antitumor activity of a series of novel alkylamine ammine dicarboxylatodichloroplatinum(IV) complexes of the general formula c,t,c-[PtCl2(OCOR1)2NH3(RNH2)]. A clear relationship existed between increasing the number of carbons in the R1 substituent and increasing cytotoxicity up to R1 = C5H11. In terms of changing the R group, maximum cytotoxic effects were conferred by alicyclic substituents. Furthermore, increasing the alicyclic ring size from cyclobutane through to cycloheptane resulted in increasing cytotoxicity. The agents with longer axial chains (e.g., JM300, R = cyclohexyl, R1 = C6H13) were significantly more cytotoxic than cisplatin and, moreover, exhibited a selective cytotoxic effect against the most intrinsically cisplatin-resistant cell lines (e.g., for HX/62, cisplatin 50% inhibitory concentration, 12.6 microM; SKOV-3, cisplatin 50% inhibitory concentration, 4.4 microM and 41 M; cisplatin 50% inhibitory concentration, 0.23 microM; JM300 was 840-, 440-, and only 34-fold more active, respectively). The dicarboxylates JM221 (R = cyclohexyl, R1 = C3H7) and JM244 (R = n-propyl, R1 = C6H5) also retained activity against a 4-fold cisplatin-acquired resistant variant of the 41M cell line. At least part of the increased cytotoxicity of the dicarboxylate, JM221, over cisplatin appeared to be attributable to an increased intracellular accumulation. This novel class of platinum compound represents a valuable lead in the development of a "third-generation" agent capable of exhibiting activity against clinical disease currently resistant to cisplatin.

Comparative in vitro cytotoxicity of taxol and Taxotere against cisplatin-sensitive and-resistant human ovarian carcinoma cell lines

Using the sulforhodamine B assay, we compared the cytotoxic properties of the novel microtubule agent taxol and the semi-synthetic related compound Taxotere in nine human ovarian-carcinoma cell lines, including three pairs of cell lines rendered resistant to cisplatin or carboplatin. In addition, the cytotoxicity of the commonly used anticancer drugs cisplatin and adriamycin and the topoisomerase II inhibitor etoposide was determined. The results of continuous drug exposure showed that taxol [mean concentration producing 50% growth inhibition (IC50), 1.1 x 10(-9) M; range, 2.8 x 10(-9)-5 x 10(-10) M and Taxotere (mean IC50, 5.1 x 10(-10) M; range, 7.2-3.3 x 10(-10) M) were greater than 1,000 times more cytotoxic than either cisplatin (mean IC50, 3.1 x 10(-6) M; P less than 0.05) or etoposide (mean IC50, 2.3 x 10(-6) M; P less than 0.05) and greater than 100 times more cytotoxic than Adriamycin (mean IC50, 6.9 x 10(-8) M; P less than 0.05). Taxotere was more cytotoxic than taxol; following continuous exposure, the mean difference across the cell lines was 2 orders of magnitude (range, 1.1-3.9 orders of magnitude for individual lines). Although this difference did not reach statistical significance for any individual cell line (P values ranged from 0.17 for HX/62 to 0.9 for OVCAR-3), when all IC50 values for the 96-h experiments were pooled, Taxotere was found to be significantly more potent than taxol (P = 0.05). Following 2 h exposure, the mean cytotoxicity of Taxotere was 3.9-fold greater than that of taxol across the nine lines (range, 0.75- to 10-fold; P less than 0.05 for the CH1 cell line; overall pooled IC50 data, P = 0.05). Although a 71-fold range of sensitivity to cisplatin was observed across the six parent cell lines (IC50 most resistant line/IC50 most sensitive line), this was largely abolished by treatment with taxol (5.6-fold range) and Taxotere (2.2-fold range). Following continuous exposure of the three pairs of lines exhibiting acquired resistance to platinum, no cross-resistance with either Taxotere or taxol was found (resistance factors, less than 1.5). In the 41M and 41McisR pair of lines, in which previous studies have shown resistance to be due to reduced platinum accumulation, taxol and Taxotere exhibited some collateral sensitivity (resistance factors, 0.69 and 0.66, respectively). Taxotere and, particularly, taxol showed a pronounced concentration times exposure duration (C x T) dependence as compared with cisplatin (P less than 0.05).(ABSTRACT TRUNCATED AT 400 WORDS)

Human ovarian-carcinoma cell lines and companion xenografts: a disease-oriented approach to new platinum anticancer drug discovery

A disease-oriented approach to the discovery of novel platinum anticancer drugs has been established through the setting up of parallel human ovarian-carcinoma cell lines and xenografts. The correlation between in vitro and in vivo antitumour activity was determined for four reference platinum agents (cisplatin, carboplatin, iproplatin and tetraplatin) in eight companion lines. Two methods of assessing antitumour effect were used in vitro (tritiated thymidine incorporation and sulforhodamine B staining) and three were applied in vivo [28-day treated/control (T/C) ratio, growth delay and specific growth delay]. In vitro, large differences in cytotoxicity across the cell lines were observed for each drug. This was also reflected in the xenografts for cisplatin and carboplatin and, to a lesser extent, for iproplatin. A correlation analysis of in vitro vs in vivo data revealed a high, statistically significant positive correlation for cisplatin and a strong positive correlation for carboplatin. However, for the two platinum(IV) drugs, the correlation was less good. In particular, tetraplatin was markedly less active in vivo (showing a general lack of activity against all of the tumour lines) than its in vitro potency against the cell lines predicted, resulting in poor correlation coefficients. These human tumour panels may be valuable for the elucidation of both cellular/molecular and corresponding in vivo pharmacological mechanisms of platinum drug resistance. Moreover, the HX/62 and SKOV-3 tumour lines, which exhibit a level of intrinsic resistance to the four reference agents both in vitro and in vivo (and which were derived from patients who had not received prior platinum therapy), represent particularly useful evaluation models for the discovery of novel broad-spectrum platinum drugs.

Purification and Characterization of Chorismate Synthase from Euglena gracilis: Comparison with Chorismate Synthases of Plant and Microbial Origin

Chorismate synthase was purified 1200-fold from Euglena gracilis. The molecular mass of the native enzyme is in the range of 110 to 138 kilodaltons as judged by gel filtration. The molecular mass of the subunit was determined to be 41.7 kilodaltons by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Purified chorismate synthase is associated with an NADPH-dependent flavin mononucleotide reductase that provides in vivo the reduced flavin necessary for catalytic activity. In vitro, flavin reduction can be mediated by either dithionite or light. The enzyme obtained from E. gracilis was compared with chorismate synthases purified from a higher plant (Corydalis sempervirens), a bacterium (Escherichia coli), and a fungus (Neurospora crassa). These four chorismate synthases were found to be very similar in terms of cofactor specificity, kinetic properties, isoelectric points, and pH optima. All four enzymes react with polyclonal antisera directed against chorismate synthases from C. sempervirens and E. coli. The closely associated flavin mononucleotide reductase that is present in chorismate synthase preparations from E. gracilis and N. crassa is the main difference between those synthases and the monofunctional enzymes from C. sempervirens and E. coli.

The relationships between glutathione, glutathione-S-transferase and cytotoxicity of platinum drugs and melphalan in eight human ovarian carcinoma cell lines

The role of glutathione (GSH) and GSH-S-transferase (GST) activity in modulating the cytotoxicity of four platinum drugs and melphalan was evaluated in eight human ovarian carcinoma cell lines. The cell lines were established from solid and ascitic tumours from pretreated and untreated patients, and showed a wide spectrum of sensitivity to several platinum II and platinum IV drugs; cisplatin, carboplatin, CHIP and tetraplatin. Intracellular glutathione concentration measured in the cell lines showed a significant (P = 0.05) correlation with IC50 values for cisplatin (r = 0.91), carboplatin (r = 0.87) and CHIP (r = 0.88). The correlation between GSH levels and IC50 values for melphalan (r = 0.76) or tetraplatin (r = 0.60) was not as significant. GST activity showed no correlation with IC50 values, for the four platinum drugs. To determine the significance of the elevated GSH concentration in the refractory cell lines, the effect of D,L-buthionine-S, R-sulfoximine (BSO) mediated GSH depletion on platinum drug cytotoxicity was examined in one of the most sensitive (CH1) and two of the least sensitive (relatively resistant; SKOV-3, HX/62) cell lines. Comparison was made with the effect of GSH depletion on melphalan cytotoxicity in these three lines. These lines were differentially sensitive to BSO, with the two most platinum drug resistant lines being more tolerant to BSO than the sensitive CH1 line. Depletion of cellular GSH, ranging between 61 and 88%, had a differential effect on the sensitivity to PtII vs PtIV drugs in the three cell lines: cytotoxicity of the PtIV drugs, tetraplatin and CHIP, was substantially enhanced in both the resistant and sensitive cell lines; in contrast, the cytotoxicity of the PtII drugs, cisplatin and carboplatin, was only significantly increased in one of the two relatively resistant lines (SKOV-3) and in the sensitive (CH1) line after GSH depletion. Moreover the dose modification factor (DMF) for the PtII agents were lower than those for PtIV agents in the three cell lines. The dose modification factor for tetraplatin after BSO treatment was similar to that observed for melphalan in all three cell lines. In the SKOV-3 cell line extending the BSO pretreatment period to 48 h from 24 h marginally reduced the cytotoxicity of cisplatin, whereas the cytotoxicity of the other three drugs remained similar to that observed after 24 h BSO pretreatment. In contrast, extending the BSO treatment to 24 h after drug exposure potentiated the cytotoxicity of cisplatin, CHIP and tetraplatin.(ABSTRACT TRUNCATED AT 400 WORDS)