Pharmacokinetic studies in mice of two new thioxanthenones (183577 and 232759) that showed preferential solid tumor activity

Two new thioxanthenones, 183577 and 232759, have rekindled interest in the development of representatives from this class of structures as useful anticancer agents. Although the mechanism of action is unknown, both compounds demonstrated a similar spectrum of solid tumor selectivity. 232759 was selected for clinical development because it showed no hepatotoxicity in preliminary studies, whereas 183577 showed hepatotoxicity but only at the maximum tolerated dose (MTD). The limiting toxicity for the clinical candidate was myelosuppression in preliminary studies. Plasma and tissue drug levels, as well as protein binding, were studied in mice using optimal administration times at the MTD for each drug (for 183577, this was a 4-h infusion at 1350 mg/m2 and for 232759, it was a 5-min injection at 240 mg/m2), as well as at one-half the MTD for the clinical candidate. The drugs were 96-100% bound by plasma proteins. The peak drug concentrations, half-life, and area under the concentration-time curve in plasma for 183577 were 3483 ng/ml, 465 min, and 2018 microgram/ml. min, respectively. The peak drug concentration, half-life, and area under the concentration-time curve in plasma for 232759 were 5257 ng/ml, 44 min, and 276 microgram/ml. min, respectively, at the MTD and 2810 ng/ml, 40 min, and 110 microgram/ml. min at one-half the MTD. In all instances of simultaneous measurements, drug concentrations were equal or higher in tissues than they were in plasma. Unlike the plasma and kidney concentrations of 183577, the liver concentrations did not show a declining trend over the 8-h observation period. Declines in plasma, liver, kidney, and tumor levels of 232759 were detected over the 8-h observation period. The sustained high 183577 concentration in liver is believed to be responsible for its prolonged half-life and hepatotoxicity. Evidence for metabolism of the parent drugs was based on the finding of additional peaks on the high-pressure liquid chromatography tracings. Future studies will focus on identification and antitumor studies of these presumed metabolites in hopes of a better understanding of the solid tumor activity profiles and toxic effects of these compounds.

Environmental monitoring during gaseous induction with sevoflurane

Recent research has shown that gaseous induction in adults with sevoflurane is an acceptable technique. This study was undertaken to assess if gaseous induction using sevoflurane carried in both oxygen alone, and in nitrous oxide and oxygen combined, would provide acceptable pollution levels. As an occupational exposure standard has not been set for sevoflurane, we used the target level of 20 ppm set by the manufacturer. Environmental monitoring was carried out in the anaesthetic room during eight lists where consecutive triple vital capacity sevoflurane inductions were performed. Time-weighted averages for both gases over the duration of the lists were well below the occupational exposure standards (mean 1.1 (range 0.6-1.7) for sevoflurane and 17.3 (12-23) for nitrous oxide). There were high peak concentrations during the induction process (8.3 (4.1-17) for sevoflurane and 172.4 (65-310) for nitrous oxide) although these decreased to low concentrations between anaesthetic inductions. Personal sampling was carried out from the anaesthetist's breathing zone and concentrations were also low (1.2 (0.8-2.1) for sevoflurane and 45.9 (10.1-261.6) for nitrous oxide.

Rapid detection and serotyping of adenovirus by direct immunofluorescence

Four fluorescent antibody reagents were evaluated for their suitability for the identification of adenovirus isolates by immunofluorescence. The antibodies used in the reagents consist of monoclonal antibodies against adenovirus type 3 (Ad3), Ad4, Ad8, and adenoviruses of subgroup C (Ad1,2,5,6), serotypes known to occur in outbreaks of disease. Most of the monoclonal antibodies employed were reactive against type-specific antigens found on the hexon protein. Reagents employing two noncompeting anti-hexon antibodies were more sensitive than reagents prepared with only one monoclonal antibody, although both types of reagents exhibited a high degree of specificity. Five hundred and seventeen adenovirus isolates (359 of which had previously been typed by other methods) and 46 nonadenovirus isolates were examined with all four type-specific reagents in parallel with an adenovirus group-specific reagent. The results indicate that direct typing of adenovirus isolates is feasible, leading to significant savings in time compared to other typing methods and should contribute to the management of certain adenovirus infections, particularly during outbreaks.

Treatment of human prostate tumors PC-3 and TSU-PR1 with standard and investigational agents in SCID mice

Both the PC-3 and the TSU-PR1 prostate tumor models were found to be satisfactory for chemotherapeutic investigations in ICR-SCID mice. The 30 to 60 mg fragments implanted took in all mice (as judged by 100% takes in the controls of all experiments as well as the passage mice). The tumor volume doubling time was 4.0 days for PC-3 and 2.5 days for TSU-PR1. Nine agents were evaluated IV against early stage subcutaneous PC-3 tumors, with Nano-piposulfan being the only agent highly active (4.9 log kill). Three other agents were moderately active: Taxol (1.5 log kill), Cryptophycin-8 (1.6 log kill), Vinblastine (1.0 log kill). Five agents were inactive: VP-16, Adriamycin, CisDDPt, 5-FUra, and Cyclophosphamide. Ten agents were evaluated IV against early stage subcutaneous TSU-PR1 tumors. Three agents were highly active, producing > 6 log kill and cures: Taxol (5/5 cures), Cryptophycin-8 (5/5 cures), Vinblastine (2/4 cures). Two other agents were moderately active: Nano-piposulfan (1.2 log kill), and Cyclophosphamide (1.1 log kill). Five agents were inactive: VP-16, Adriamycin, CisDDPt, 5-FUra, and BCNU. In part, activity was determined by the ability of the SCID mice to tolerate meaningful dosages of the agents. Agents producing granulocyte toxicity (e.g., Adriamycin) were poorly tolerated and appeared less active than expected. Vinblastine, producing little or no granulocyte toxicity was very well tolerated and appeared to be more active than expected.

Self-reports on the Eating Disorder Inventory by female aerobic instructors

This study examined the possibility of eating disorders in 30 female aerobic dance instructors. All subjects completed a biographical questionnaire and the Eating Disorder Inventory. The results showed that the aerobic instructors yielded scores which were comparable to similarly aged female weight lifters but tended to be lower than those of women distance runners (also of similar age). Interestingly, 23% (n = 7) of the subjects reported a previous history of bulimia and 17% (n = 5) reported a previous history of anorexia. Thus, 40% of the instructors indicated a previous experience with eating disorders. Based on all 30 participants, the mean scores associated with Body Dissatisfaction, Drive for Thinness, Ineffectiveness, and Perfectionism were quite comparable to those previously established for anorexic groups. In addition, a relatively high percentage of the sample yielded scores which were actually greater than mean values associated with anorexia patients on nine of the 11 subscales. Based on these results, a number of the aerobic dance instructors possessed scores suggesting behaviors and attitudes consistent with female athletes whose sports emphasize leanness and comparable to those who have eating disorders.

Preclinical anticancer activity of cryptophycin-8

Cryptophycin-8 was prepared by the conversion of the epoxide group on cryptophycin-1 to a chlorohydrin. In the studies reported here, cryptophycin-8 was evaluated for preclinical activity against subcutaneous tumors of both mouse and human origin. At the highest non-toxic single course treatment, the following results were obtained (Table A). Cryptophycin-8 was less potent than cryptophycin-1 by approximately 4-fold; however, it was both more water soluble and had greater therapeutic efficacy, as demonstrated by % T/C, tumor cell log kill values, range of dose effectiveness and host cures.

Bile duct stenting: a comparison of the One-Action Stent introduction system with the conventional delivery system

BACKGROUND AND STUDY AIMS

A "One-Action Stent Insertion System" (OASIS) for use with biliary stents has been produced, which is said to be easier to use than conventional insertion systems. The aim of this study was to assess whether there was any measurable difference in the technique in a comparison between the two methods.

PATIENTS AND METHODS

A prospective study was carried out. Twenty consecutive patients requiring stents for biliary obstructing lesions were randomly allocated to have the stent inserted either using the OASIS system or the conventional system. All the sent insertions were performed by two experienced endoscopists. The actual time of the insertion procedure and the screening time were recorded.

RESULTS

Patients' tolerance for the procedure was similar in the two groups. In nine out of ten OASIS stent insertions, the endoscopist considered the procedure to be easy, compared with five out of ten conventional stent placements. Both techniques resulted in satisfactory positioning of the stent in nine out of ten patients. Although there was no statistically significant difference in the screening times for the two methods (p = 0.16), the actual time taken using the conventional method was significantly longer than with the OASIS method (p < 0.001).

CONCLUSION

The One-Action Stent Insertion Set (OASIS) allows easier insertion of biliary stents. The system decreases the number of exchanges that need to be undertaken, precluding inadvertent wire displacement and the need to reinitiate cannulation and guide wire insertion. The actual time required for insertion is significantly less using this method, and this may also reduce the radiation exposure.

Duodenal mucosal histology and histochemistry in active, treated and healed duodenal ulcer: correlation with duodenal prostaglandin E2 production

We investigated whether impaired duodenal mucosal prostaglandin E2 (PGE2) production previously observed in duodenal ulcer (DU) was a primary pathophysiological abnormality or secondary to mucosal architectural changes that accompany ulceration. One hundred patients were studied: at endoscopy, paired duodenal biopsies were taken in patients with normal endoscopies and from the ulcer edge or scar and background mucosa in active or healed DU. One of the pair of biopsies was used to estimate PGE2 synthesis ability, the other was processed for histology and histochemistry. The following features graded: goblet cell numbers and staining with Periodic acid-Schiff reagent (PAS), epithelial staining with PAS, villous atrophy, columnar cell height, inflammatory cell infiltrate and micro-erosions and gastric metaplasia taken as a whole. Patients were found to have normal endoscopy (n = 31), active untreated DU (n = 20) active DU on treatment with either cimetidine or ranitidine (n = 13), healed DU on maintenance treatment (n = 27) and healed DU off treatment (n = 9). Active duodenal ulceration was found to be associated with decreased numbers of goblet cells, loss and blunting of villi, increased columnar cell height, increased epithelial cell PAS staining and with gastric metaplasia. After healing, only villous blunting remained. These changes were present, but less marked, at sites removed from the ulcer and were not apparent in the patient groups with healed ulcers. A strong correlation between overall gastric metaplasia and epithelial cell PAS staining and the reduced ability to synthesize PGE2 (P < 0.001) was only apparent when biopsies from all patients were grouped together, but not within individual patient subgroups. There was no consistent correlation between PGE2 generation and individual parameters of pathological change in duodenum. We conclude that, although inflammatory and mucosal changes may contribute, the evidence suggests that the impaired PGE2 generation in DU disease is, to a large extent, independent of histological and histochemical features.

Formulation and antitumor activity evaluation of nanocrystalline suspensions of poorly soluble anticancer drugs

PURPOSE

Determine if wet milling technology could be used to formulate water insoluble antitumor agents as stabilized nanocrystalline drug suspensions that retain biological effectiveness following intravenous injection.

METHODS

The versatility of the approach is demonstrated by evaluation of four poorly water soluble chemotherapeutic agents that exhibit diverse chemistries and mechanisms of action. The compounds selected were: piposulfan (alkylating agent), etoposide (topoisomerase II inhibitor), camptothecin (topoisomerase I inhibitor) and paclitaxel (antimitotic agent). The agents were wet milled as a 2% w/v solids suspension containing 1% w/v surfactant stabilizer using a low energy ball mill. The size, physical stability and efficacy of the nanocrystalline suspensions were evaluated.

RESULTS

The data show the feasibility of formulating poorly water soluble anticancer agents as physically stable aqueous nanocrystalline suspensions. The suspensions are physically stable and efficacious following intravenous injection.

CONCLUSIONS

Wet milling technology is a feasible approach for formulating poorly water soluble chemotherapeutic agents that may offer a number of advantages over a more classical approach.

A new method for active surveillance of adverse events from diphtheria/tetanus/pertussis and measles/mumps/rubella vaccines

We describe a new method for active post-marketing surveillance of vaccine safety based on patient records. We studied the association between diphtheria/tetanus/pertussis (DTP) vaccination and febrile convulsion, and between measles/mumps/rubella (MMR) vaccination and febrile convulsion and idiopathic thrombocytopenic purpura (ITP) in five district health authorities in England by linking vaccination records with computerised hospital admission records. We found an increased relative incidence for convulsions 0-3 days after DTP vaccination. The effect was limited to the third dose of vaccine for which the attributable risk (all ages) was 1 in 12,500 doses. Completion of vaccination by 4 months instead of 10 months after the change in the UK to an accelerated immunisation schedule may have resulted in a 4-fold decrease in febrile convulsions attributable to DTP vaccine. 67% of admissions for a convulsion 6-11 days after MMR vaccination were attributable to the measles component of the vaccine (risk 1 in 3000 doses). An excess of admissions for a convulsion 15-35 days after MMR vaccination was found only for vaccines containing the Urabe mumps strain (1 in 2600 Urabe doses). There was a causal association between MMR vaccination and ITP resulting in admission 15-35 days subsequently; there was no evidence of a mumps strain-specific effect. The estimated absolute risk of 1 in 24,000 doses was 5 times that calculated from cases passively reported by clinicians. This finding emphasises the need for active surveillance of adverse events. The record linkage method that we used is an effective way to identify vaccine-attributable adverse events.

New murine polymorphisms detected by random amplified polymorphic DNA (RAPD) PCR and mapped by use of recombinant inbred strains

Oligonucleotide primers of random sequence that were 12 bases in length, 58% in GC content, and lacking internal palindromes were designed. By random amplified polymorphic DNA (RAPD) PCR, these primers were used to survey for DNA variations between the progenitors of the mouse AXB and BXA recombinant inbred sets (A/J and C57BL/6J). We identified 17 DNA variants detected by 10 primers. Map positions for these variants were determined by comparing their strain distribution patterns in the AXB, BXA recombinant inbred sets with strain distribution patterns of previously published loci. When necessary, BXD and NXSM recombinant inbred sets were also used. These 17 new loci mapped to 12 chromosomes. The 10 primers were also used to survey 20 inbred mouse strains including the progenitors of other recombinant inbred sets and four mouse strains recently inbred from the wild (CAST/Ei, MOLF/Ei, PERA/Ei, and SPRET/Ei).

The inotropic and hemodynamic effects of intravenous milrinone when reflex adrenergic stimulation is suppressed by beta-adrenergic blockade

Milrinone is an inotropic and vasodilator agent proven to be effective in the treatment of heart failure. This study evaluated whether milrinone produces inotropic and hemodynamic effects independent of reflex adrenergic stimulation. Eleven stable heart failure patients (New York Heart Association class II to III) undergoing cardiac catheterization received intravenous (i.v.) milrinone (50 micrograms/kg for 10 minutes followed by 0.5 micrograms/kg/min for 50 minutes) during beta-adrenergic blockade. After beta-blockade with a 50-mg oral dose of metoprolol, heart rate decreased by a mean of 16.6%. The peak inotropic response to i.v. milrinone measured using the maximum rate of rise of left ventricular pressure (LV dP/dt) was fully developed at 20 minutes. Mean absolute inotropic response of LV dP/dt from baseline was statistically significant at 10, 20, 30, and 40 minutes (P < 0.05). Mean percentage increase in cardiac index from baseline was statistically significant at 20 and 30 minutes, and mean absolute decline from baseline for pulmonary capillary wedge pressure was statistically significant at 20 and 40 minutes (P < 0.05). The inotropic and hemodynamic effects of i.v. milrinone were thus preserved during beta-adrenergic blockade. This finding is consistent with a mechanism of action of i.v. milrinone--myocardial phosphodiesterase inhibition--that is independent of reflex adrenergic stimulation.

Patients with adenomatous polyps and carcinomas have increased colonic mucosal prostaglandin E2

Colorectal carcinoma in humans and animal models is associated with increased synthesis of prostaglandin E2 (PGE2). PGE2 synthesis was measured in normal and neoplastic human colorectal mucosa to investigate its role in the adenoma-carcinoma sequence. Paired mucosal biopsy specimens for PGE2 synthesis and histological examination were obtained during 39 diagnostic colonoscopies. Twelve control patients in whom colonoscopies and histology were normal synthesised similar amounts of PGE2 at all sites. Their results were (mean (SD) pg PGE2/mg tissue) caecum 102.8 (15.9) (n = 6), ascending colon 110.8 (24.3) (n = 10), transverse colon 103.9 (19.5) (n = 11), descending colon 102.9 (23.2) (n = 12), sigmoid colon 96.4 (18.0) (n = 12), and rectum 107.1 (17.6) (n = 12). Nineteen patients had a total of 27 adenomatous polyps (rectum (1), sigmoid (22), descending (1), transverse (1), and ascending colon (1): histology-tubular (16), tubulo-villous (8), and villous adenomous (3)). The polyps (178.0 (55.0), n = 27) synthesised more PGE2 than controls (p < 0.001), but the values in polyp-associated mucosa (mean (SD) 115.4 (21.9), n = 15) were not different to control results. Eight patients had carcinomas (rectal (2), sigmoid (4), and caecal (2)) all of which were adenocarcinomas. The cancers (193.6 (40.2), n = 8) synthesised more PGE2 than control specimens (p < 0.001), but were not different to polyps. Cancer-associated mucosa (140.3 (27.7) n = 8) synthesised more PGE2 than control and polyp-associated mucosa. Colorectal neoplasia is associated with a progressive increase in PGE2 synthesis which may have a role in tumourigenesis and be a pathophysiological explanation for the beneficial effects of NSAIDs in animal models and human disease.

Thyroid storm as a cause of loss of consciousness following anaesthesia for emergency caesarean section

A previously undiagnosed thyrotoxic patient was anaesthetised for an emergency Caesarean section. The recovery period was complicated by an acute thyroid crisis resulting in loss of consciousness following an apparently normal recovery from general anaesthesia.

Risk of aseptic meningitis after measles, mumps, and rubella vaccine in UK children

Cases of aseptic meningitis associated with measles/mumps/rubella vaccine were sought in thirteen UK health districts following a reported cluster in Nottingham which suggested a risk of 1 in 4000 doses, substantially higher than previous estimates based on cases reported by paediatricians (4 per million). Cases were ascertained by obtaining vaccination records of children with aseptic meningitis diagnosed from cerebrospinal fluid samples submitted to Public Health Laboratories or discharged from hospital with a diagnosis of viral meningitis. Both methods identified vaccination 15-35 days before onset as a significant risk factor and therefore indicative of a causal association. With both, half the aseptic meningitis cases identified in children aged 12-24 months were vaccine-associated with onset 15-35 days after vaccine. The study confirmed that the true risk was substantially higher than suggested by case reports from paediatricians, probably about 1 in 11,000 doses. However, the possibility that the aseptic meningitis induced by vaccination was largely asymptomatic and a chance laboratory finding in children investigated for other clinical conditions, particularly febrile convulsions, could not be excluded. Comparison of national reports of virus-positive mumps meningitis cases before and after the introduction of this vaccine indicated that the risk from wild mumps was about 4-fold higher than from vaccine. Altogether, 28 vaccine-associated cases were identified, all in recipients of vaccines containing the Urabe mumps strain. The absence of cases in recipients of vaccine containing the Jeryl Lynn strain, despite its 14% market share, suggested a higher risk from Urabe vaccine. A prospective adverse event surveillance system using the study methods is currently being established to assess the risk, if any, from the Jeryl Lynn strain which is now the only mumps vaccine used in the UK.

Bleeding oesophageal varices in alcoholic cirrhosis: long-term follow-up of endoscopic sclerotherapy

Between 1977 and 1984, 53 consecutive unselected patients with bleeding oesophageal varices and alcoholic cirrhosis were treated by endoscopic sclerotherapy. Ten died during their index bleed, and 10 died within the following year due to hepatic failure (five), non-liver related causes (three), bleeding varices (one) and hepatocellular carcinoma (one). After the first year, a further three patients died of bleeding varices, eight died of hepatic failure (including one hepatocellular carcinoma) and six died of unrelated problems. Patients with hepatic disease of Childs-Pugh grade C died earlier than those of grade A and B grade (p < 0.01). There were 24 variceal recurrences within 1 year of completing sclerotherapy and seven recurrences later. Abstemious alcoholics rarely rebled and none developed recurrent varices after 18 months without recurrence. The size of the original varices, the number of sessions required to obliterate them, and the total volume of sclerosant used did not correlate with duration of remission. Continuing drinkers were more likely to present with bleeding varices (six of nine) than asymptomatic recurrences (one of 23) (p < 0.0001). In this study endoscopic sclerotherapy prevented deaths from variceal bleeds but there was a continued risk of death from hepatic failure and other unrelated causes.

Multilocus markers for mouse genome analysis: PCR amplification based on single primers of arbitrary nucleotide sequence

Polymerase chain reaction (PCR) based on single primers of arbitrary nucleotide sequence provides a powerful marker system for genome analysis because each primer amplifies multiple products, and cloning, sequencing, and hybridization are not required. We have evaluated this typing system for the mouse by identifying optimal PCR conditions; characterizing effects of GC content, primer length, and multiplexed primers; demonstrating considerable variation among a panel of inbred strains; and establishing linkage for several products. Mg2+, primer, template, and annealing conditions were identified that optimized the number and resolution of amplified products. Primers with 40% GC content failed to amplify products readily, primers with 50% GC content resulted in reasonable amplification, and primers with 60% GC content gave the largest number of well-resolved products. Longer primers did not necessarily amplify more products than shorter primers of the same proportional GC content. Multiplexed primers yielded more products than either primer alone and usually revealed novel variants. A strain survey showed that most strains could be readily distinguished with a modest number of primers. Finally, linkage for seven products was established on five chromosomes. These characteristics establish single primer PCR as a powerful method for mouse genome analysis.

Organization and chromosomal locations of Rap1a/Krev sequences in the mouse

The human RAP1A gene encodes a protein that apparently can antagonize the function of oncogenic ras genes in gene transfer experiments, but its normal function is unknown. To understand the function of this gene, we have undertaken a study of the mouse homolog, Rap1a. The complete coding sequence of a mouse Rap1a cDNA has been determined, and genomic clones representing three distinct Rap1a species were recovered. We find that Rap1a is located on distal mouse Chromosome (Chr) 3 near Nras, Ampd-1, Tshb, Ngfb, and Atp1a1. Two related sequences (Rap1a-rs1 and Rap1a-rs2) were also characterized. Rap1a-rs1, which was not localized, has a sequence very similar to the Rap1a cDNA, suggesting that it has been recently acquired by the mouse genome. Rap1a-rs2 is more distantly related to the gene sequence and is located on Chr 2 near Actc-1.

Antibiotic therapy, clinical features and outcome of 36 adults presenting to hospital with proven influenza: do we follow guidelines?

The impact of the 1989/1990 influenza epidemic on the Nottingham hospitals was assessed in a retrospective survey. Thirty-six cases of proven influenza were identified, 14 of whom died. Non-survivors were more likely to be confused, uraemic and to lack focal chest signs and symptoms. Antibiotic therapy both prior to admission and following hospitalization was not optimal and, in many cases, failed to follow previously published guidelines. Such guidelines need emphasis during influenza epidemics.