Clenbuterol plasma concentrations after therapeutic administration in fit Standardbred horses: threshold recommendations

Clenbuterol, (RS)-1-(4-amino-3,5-dichlorophenyl)-2-(tert-butylamino)ethan-1-ol, as Ventipulmin is an FDA approved β2 agonist medication for the management of airway obstruction in horses. Administration above the FDA approved doses for clenbuterol produces repartitioning effects, which have led to restrictions on its use in human athletics and Quarter Horse and Thoroughbred racing. Clenbuterol, however has long been used therapeutically at FDA approved doses in Harness racing. The goal of this study was to identify a withdrawal time guideline for its use at FDA approvsed dose levels in Harness racing, where horses may start at seven-day intervals. Eight healthy, moderately fit Standardbred horses (4 mares, 4 geldings, weight 491±40 kg, age 13±2 years) were administered 0.8 μg/kg of clenbuterol as Ventipulmin syrup twice daily (BID) for three days. Blood samples were collected prior to dosing and at 1, 24, 48 and 96 h post administration. Clenbuterol was quantified in all samples using the New York Drug Testing and Research Laboratory ISO-17025 Racing and Medication Testing Consortium (RMTC) accredited quantitative procedure. The lower limit of quantitation of the method was 1.0 pg/ml, and three data points at 96 h post administration were censored. One horse developed diarrhoea and data from this horse was excluded from the overall analysis. Plasma regulatory thresholds were calculated using the 95/95 tolerance method and Gauss Camp Meidell at P=0.05 and P=0.001. Horses were also evaluated for effects of clenbuterol on body composition using body mass and ultrasound measurements of rump fat thickness. There were no effects (P>0.05) of clenbuterol on any of the measures including fat mass and fat free mass and thus no repartitioning effect was observed. The pharmacokinetic data and the 96 h data set support the therapeutic use of clenbuterol in Harness horses at the FDA approved 0.8 μg/kg BID dose for three days and suggest a 41 pg/ml regulatory threshold for a 96 h withdrawal time with a P=0.001 probability of randomly exceeding this regulatory threshold.

Dexamethasone serum concentrations after intravenous administration in horses during race training

Dexamethasone (DXM) sodium phosphate is a widely used corticosteroid for inflammatory conditions in horses, regulated in racing jurisdictions in the USA by a 0.005 ng/ml serum/plasma threshold. This study seeks to describe serum concentrations of DXM at 48 and 72 h after intravenous administration of 20 mg DXM sodium phosphate over 1 to 5 days, and to identify a possible source of DXM overages. 74 horses (39 Thoroughbreds, 13 Standardbreds, 22 Quarter Horses) in active race training received 20 mg DXM sodium phosphate. Serum was collected before injection, at 48 and 72 h post last injection, and analysed by LC/MS-MS (limit of quantification (LOQ) = 2.5 pg/ml). No differences were identified by ANOVA (P≤0.05) for racing breeds, age, gender or the number of days of DXM sodium phosphate administration, so data were pooled for each time point. The DXM serum concentration at 48 h (mean ± standard deviation, range) was 2.18±1.56 pg/ml (<2.5 to 40 pg/ml). Summary statistics could not be derived for 72 h DXM serum concentration data owing to censored data, but ranged from <2.5 to 95.8 pg/ml. There was one extreme outlier (Tukey) at 48 h, and two extreme outliers at 72 h. A separate study was conducted using sedentary experimental horses to determine the likelihood that positive DXM samples could result from environmental transfer. Urine was collected from a mare 2 to 3 h post administration of 20 mg DXM. Hay with 100 ml of the DXM (17 ng/ml) containing urine was offered to each of six experimental horses and blood was collected at 0, 4, 8, 12, 16, 20 and 24 h. All six horses had plasma DXM concentration above the limit of detection and five of six had plasma DXM concentrations above the LOQ for at least one sample time.

Evaluation of cobalt as a performance enhancing drug (PED) in racehorses

Cobalt is a required trace element in animals, but administration in excess is considered dangerous and potentially performance enhancing in equine athletes. This study seeks to determine if cobalt may actually act as a performance enhancing drug (PED) by altering biochemical parameters related to red blood cell production as well as markers of aerobic and anaerobic exercise performance. In addition, for adequate regulation of naturally occurring substances, such as cobalt, its distribution among the population must be defined. In order to identify this distribution, plasma Cobalt was determined from 245 Standardbred horses with no cobalt supplementation from farms in New York and New Jersey, including horses at the Rutgers University Equine Science Center. Samples were analysed by Inductively Coupled Plasma Mass Spectrometry. Seven healthy, race fit Standardbreds (4 geldings, 3 mares, age: 5±3 years, ~500 kg) were used for the PED experiment. An incremental graded exercise test (GXT) to measure maximal aerobic capacity (V̇O2max) and markers of performance, measurement of plasma volume and blood volume as well as the measurement of lactate, erythropoietin (EPO), and various blood haematological factors were determined 7 days prior to cobalt administration. Each horse was administered a sterile solution of cobalt salts (50 mg of elemental Co as CoCl2 in 10 ml of saline, IV) at 9 AM on three consecutive days via the jugular vein. Blood samples were obtained from the contralateral jugular vein before and at 1, 2, 4 and 24 h after administration. Plasma and blood volume were measured one day after the last dose of cobalt, and a post administration GXT was performed the next day. Horses were observed for signs of adverse effects of the cobalt administration (agitation, sweating, increased respiration, etc.). Plasma cobalt concentration increased from a pre-administration mean of 1.6±0.6 to 369±28 μg/l following 3 doses of the cobalt solution (P<0.05). This Co concentration was unaccompanied by changes in aerobic or anaerobic performance, plasma EPO concentration, plasma volume, resting blood volume, total blood volume, or estimated red blood cell volume (P>0.05). There were no observed adverse effects.

An interim screening limit of detection for naproxen in equine plasma: a review and analysis

Starting in August 2015 Thoroughbred racing in Charles Town, West Virginia experienced a sequence of intermittent low concentration Naproxen identifications from 6.3 to 161 ng/ml of plasma (27.3 to 699 nM). These identifications were ongoing, indicating the horsemen were unaware of their origins. Naproxen is administered orally to horses at substantial doses and is chemically stable in the environment. These identifications are therefore most likely associated with exposure of these horses to environmental traces of Naproxen. Given the low concentrations of these identifications, we were asked to identify a Screening Limit of Detection (SLOD) below which these trace level Naproxen identifications would not be reported. Review of the data set suggested an SLOD of 200 ng/ml, while outlier analysis suggested an ‘extreme’ outlier level at 247 ng/ml, which figure was rounded up to 250 ng/ml Naproxen or 1.09 uM. This proposed SLOD is in good agreement with other US regulatory thresholds for therapeutic medications and this Interim Screening Limit of Detection was presented for review.

Digital Rectal Examination and Transrectal Ultrasonography in Staging of Rectal Cancer

Staging of rectal carcinoma before surgical treatment was performed in a prospective blind study, comparing digital rectal exploration and transrectal linear ultrasonography (TRUS) with the resulting pathological examination. TRUS underestimated depth of penetration in 3 of 33 patients and overestimation resulted in 9 of 74. The figures for digital examination were 5 of 18 and 20 of 76, respectively. Penetration of the rectal wall was correctly identified in 56 of 61 patients by digital examination and in 59 of 61 by TRUS. Specimens without penetration of the rectal wall were identified in 26 of 33 patients by TRUS, but in not more than 13 of 33 by digital examination. Regional lymph node metastases were present in 19 patients; none were diagnosed by digital examination, but TRUS identified 11 of the 19. It is concluded that TRUS will result in more patients having the possibility of local surgery for cure.

Cobalt use and regulation in horseracing: a review

Cobalt, atomic weight 58.9, is a metallic element and environmental substance found in the animal in microgram quantities, predominantly as vitamin B12, but is also a component of at least one mammalian enzyme unassociated with B12. Cobalt is a required trace mineral and has long been administered as a dietary supplement to humans and animals. Cobalt deficiency outside of its requirement in vitamin B12 has not been reported in humans. The administration of cobalt salts was once standard treatment for anaemia in humans, owing to its ability to stimulate red blood cell synthesis. Elemental cobalt acts by stabilising hypoxia inducible factor (HIF-1α), which activates the erythropoietin gene, which in turn increases haemoglobin/red blood cell synthesis, which had led to a presumption that cobalt may be performance enhancing in athletes. Administration of cobalt in amounts sufficient to significantly increase the haematocrit are associated with risk of toxicity in humans, and the only cobalt administration study in horses showed no effect on red blood cell parameters or toxicity. Because of the perception that cobalt administration may enhance athletic performance, racing regulators have recently begun to restrict cobalt use in horseracing which has led to the introduction of cobalt thresholds in several racing jurisdictions. The International Federation of Horseracing Authorities is considering an international regulatory threshold for cobalt of 100 ng/ml in urine, based on studies performed in five different countries. In the United States, the Racing Commissioners International has recently set a primary plasma threshold of 25 ng/ml and secondary threshold of 50 ng/ml. One New York and New Jersey racetrack owner has initiated testing for cobalt and has denied his facilities to trainers whose horses tested positive for excessive quantities of cobalt. This review seeks to summarise what is known about the use of cobalt in horse racing.

Bovine colostrum supplementation optimises earnings, performance and recovery in racing Thoroughbreds

Bovine colostrum (BC) is the first milk produced by cows after calving and contains numerous beneficial substances for the immunity and development of the newborn calf. Because of the growth and immune factors in BC, it has become an attractive supplement for use by athletes to support immunity and health during athletic performance. In order to evaluate the effects of oral BC supplementation on equine athletes, this study evaluated the earnings, performance, recovery and incidence of upper respiratory infections (URTI) in racing horses. The study design was a randomized cross-over racing performance study. 21 horses in race training were randomly assigned to train and compete with or without BC supplementation. After each horse competed in three races, it was crossed over to the other group, allowed a three week washout period, and then competed in three additional races. Horses in public training stables of 3 participating trainers were used. Race performance as determined by earnings, Bloodstock Research Information System (BRIS) speed figures, recovery as determined by number of days between races and incidence of upper respiratory tract disease was recorded. 11 horses completed the study. There was no effect of the order of BC supplementation on the measured variables. Horses on BC supplementation earned $ 2,088 more purse money per race, than when unsupplemented (P=0.016), and ran an average of 5 BRIS speed points higher (P=0.03). Horses returned to racing on average 7.5 days faster (16.9 days vs 24.4 days, P=0.048). There were no URTI among the horses on BC supplementation and two infections while not on BC supplementation (z-test, P=0.11). Statistical analysis showed that horses recovered more quickly, earned three times more money and raced better as judged by BRIS scores while competing with BC supplementation. BC supplemented horses also experienced fewer URTI, although this effect was not significant.

Microglia and macrophages express tumor necrosis factor receptor p75 following middle cerebral artery occlusion in mice

The proinflammatory and potential neurotoxic cytokine tumor necrosis factor (TNF) is produced by activated CNS resident microglia and infiltrating blood-borne macrophages in infarct and peri-infarct areas following induction of focal cerebral ischemia. Here, we investigated the expression of the TNF receptors, TNF-p55R and TNF-p75R, from 1 to 10 days following permanent occlusion of the middle cerebral artery in mice. Using quantitative polymerase chain reaction (PCR), we observed that the relative level of TNF-p55R mRNA was significantly increased at 1-2 days and TNF-p75R mRNA was significantly increased at 1-10 days following arterial occlusion, reaching peak values at 5 days, when microglial-macrophage CD11b mRNA expression was also increased. In comparison, the relative level of TNF mRNA was significantly increased from 1 to 5 days, with peak levels 1 day after arterial occlusion. In situ hybridization revealed mRNA expression of both receptors in predominantly microglial- and macrophage-like cells in the peri-infarct and subsequently in the infarct, and being most marked from 1 to 5 days. Using green fluorescent protein-bone marrow chimeric mice, we confirmed that TNF-p75R was expressed in resident microglia and blood-borne macrophages located in the peri-infarct and infarct 1 and 5 days after arterial occlusion, which was supported by Western blotting. The data show that increased expression of the TNF-p75 receptor following induction of focal cerebral ischemia in mice can be attributed to expression in activated microglial cells and blood-borne macrophages.

Eosinophilia in the upper gastrointestinal tract is not a characteristic feature in cow's milk sensitive gastro-oesophageal reflux disease. Measurement by two methodologies

BACKGROUND

An association between cow's milk hypersensitivity (CMH) and gastro-oesophageal reflux disease (GERD) in childhood has been reported in the past decade.

AIM

To assess whether biopsies from the upper gastrointestinal tract of children with cow's milk sensitive GERD have a specific allergic inflammatory pattern, and to compare two different techniques for measuring inflammatory cells in gastrointestinal biopsies.

METHODS

GERD was diagnosed by means of endoscopy and oesophageal pH monitoring. Hypersensitivity to cow's milk was determined by an elimination diet and cow's milk challenge. Allergic inflammatory cells in upper gastrointestinal biopsies were identified by immunohistochemistry and their numbers were assessed by two different methods-counting the number of cells/high power field and using the computerised Cast-Grid system.

RESULTS

Cow's milk sensitive GERD was identified in 10 of 17 children with severe GERD (median age, 7.8 years). Biopsies from children with endoscopic oesophagitis had significantly increased numbers of mast cells and T cells. No differences in the number of eosinophils, mast cells, or T cells were found between children with CMH and those with primary GERD. Several differences were found between the two different histological quantification methods.

CONCLUSIONS

CMH was found not only in infants but also in school age children with GERD. Histology did not identify the cow's milk sensitive GERD subgroup. The computerised histological method provides a more complete evaluation based upon total biopsy area, and helped to limit the bias of uneven biopsy size.

Randomized study of biennial screening with a faecal occult blood test: results after nine screening rounds

BACKGROUND

Two large true population studies in Europe have shown a significant reduction in mortality from colorectal cancer (CRC) by screening with a faecal occult blood test. In one trial conducted in Funen County, 61,933 individuals (aged 45-75 years) were randomly allocated either to a control group or to receive a biennial Hemoccult-II test.

METHODS

These individuals were followed from 1985 to 2002 and 9 screening rounds were performed.

RESULTS

First screening was accepted by 67% (20,672). Positivity rates varied between 0.8% and 3.8%, and the cumulative proportion of the test group having colonoscopy was 5.3%. Screen-detected CRC was early (Dukes' A) in 36% compared to 11% among controls. Incidence of CRC was unchanged, but mortality was reduced by 11%. This figure increased to 43% in persons participating in all 9 rounds. No more than 8,558 were screened at the 9th round. Patients with CRC detected between screenings had better survival than controls. Death rates from causes other than CRC among participants never became higher than among controls.

CONCLUSION

The lesser reduction in mortality from CRC of 11% compared to 18% after 5 screening rounds may be explained by the decrease in the number screened. Efficacy in those screened supports the introduction of countrywide screening in Denmark, but it must be ascertained that acceptability, proportion of early CRC and logistics all reach the same standard as in the randomized trial.

Colorectal adenoma characteristics as predictors of recurrence

PURPOSE

The identification of groups with a high risk of colorectal adenoma recurrence remains a controversial issue for clinicians. This study was designed to assess the predictive value of initial patient and adenoma characteristics of the three-year recurrence.

METHODS

The study population was composed of 552 patients with resected colorectal adenomas who completed the European Fiber-Calcium Intervention trial. At both baseline and three-year examinations, the characteristics of adenomas were recorded according to a standardized protocol. The main outcomes measured were the three-year overall recurrence, recurrence of multiple adenomas, recurrence of advanced adenomas (size > or = 1 cm or tubulovillous/villous architecture or moderate/severe dysplasia), and proximal and distal recurrence.

RESULTS

A three-year recurrence was observed in 122 patients (22.1 percent), and more than one-half of them had recurrent adenomas on the proximal colon. After adjustment for patient characteristics and treatment allocation, the number of adenomas and their proximal location at baseline were the main predictors of recurrence. In comparison with patients who had one or two adenomas on the distal colon, patients with three or more adenomas with at least one of them located on the proximal colon had a much higher risk of overall recurrence (5.3; 95 percent confidence interval, 2.7-10.3), proximal recurrence (8.5; 95 percent confidence interval, 4.1-18), and advanced adenoma recurrence (5.5; 95 percent confidence interval, 2.4-12.6).

CONCLUSIONS

Follow-up colonoscopies in patients with adenomas should include careful examination of the proximal colon. The time interval between follow-up examinations could probably be extended beyond three years in patients who have only one or two distal adenomas.

Recurrence and survival after mesorectal excision for rectal cancer

BACKGROUND

Mesorectal excision for rectal cancer has resulted in local recurrence rates of 3-11 per cent compared with up to 38 per cent after conventional methods. The results of a prospective Danish study with a historical control group are presented.

METHODS

Three hundred and eleven patients with a mobile rectal cancer had mesorectal excision with curative intent performed by certified surgeons and were followed for 3 years. Demographic, perioperative and follow-up data were recorded prospectively. A series of patients who had conventional operations for rectal cancer served as a control group.

RESULTS

The cumulative 3-year local recurrence rate was 11 per cent after mesorectal excision compared with 30 per cent after conventional surgery (hazard ratio (HR) 0.33 (95 per cent confidence interval (c.i.) 0.21 to 0.52); P < 0.001). Multivariate regression analysis showed that only advanced age (HR 0.97 (95 per cent c.i. 0.94 to 1.00); P = 0.048) and tumour in the lower third of the rectum (HR 0.21 (95 per cent c.i. 0.04 to 1.97); P = 0.075) were marginal independent predictors of local recurrence after mesorectal excision. The cumulative crude 3-year survival rate was 77 per cent after mesorectal excision and 62 per cent after conventional surgery (HR 0.58 (95 per cent c.i. 0.43 to 0.77); P < 0.001). Age was the only independent predictor of death after mesorectal excision (HR 1.04 (95 per cent c.i. 1.02 to 1.07); P = 0.001).

CONCLUSION

Mesorectal excision is associated with a considerably lower risk of local recurrence and a better survival rate than conventional surgery, and is the optimum method for rectal cancer resection.

Diagnostic yield in a biennial Hemoccult-II screening program compared to a once-only screening with flexible sigmoidoscopy and Hemoccult-II

BACKGROUND

Flexible sigmoidoscopy (FS) has a higher degree of sensitivity for detecting colorectal neoplasia in the left side of the colon than Hemoccult (H-II). However, no randomized controlled trial has compared a single FS screening with a H-II screening program (annual or biennial) despite the well-documented mortality reduction from colorectal cancer (CRC) in the latter. The aim was to compare the diagnostic yield of colorectal neoplasia in two aged-matched groups from two different randomized screening trials; one group screened by a single FS+H-II, the other with biennial H-II over the course of 16 years.

METHODS

24,465 persons invited to participate in the Funen biennial H-II screening program were compared with 4,460 similar persons invited to another Funen trial using a single FS+H-II.

RESULTS

Compliance in the biennial H-II program was 65.5% during the first screening round compared to 39.8% for FS+H-II. The cumulative number of persons with positive tests was 8.2% (positive H-II) in the biennial H-II program during 16 years and 20.3% (polyps > 3 mm in diameter seen at FS or positive H-II) for once-only FS+H-II. The diagnostic yield of CRC per 1,000 screened was 9.9 in the biennial H-II program and 6.6 after FS+H-II (6.5 and 2.7 per 1,000 invited). The yield of advanced adenomas (> or = 10 mm and/or villous structure and/or severe dysplasia) was 2.3% in the H-II program and 3.3% after FS+H-II among the screened persons, but this difference disappeared when persons invited, but not necessarily screened, were compared (1.5% versus 1.3%).

CONCLUSION

Screening with H-II in a biennial screening program during 16 years detected more CRCs than a single screening with FS+H-II and a similar number of advanced adenomas.

The scavenger receptor, cysteine-rich domain-containing molecule gp-340 is differentially regulated in epithelial cell lines by phorbol ester

Gp-340 is a glycoprotein belonging to the scavenger receptor cysteine rich (SRCR) group B family. It binds to host immune components such as lung surfactant protein D (SP-D). Recent studies found that gp-340 interacts directly with pathogenic microorganisms and induces their aggregation, suggesting its involvement in innate immunity. In order to investigate further its potential immune functions in the appropriate cell lines, the expression of gp-340 in four conventional immune cell lines (U937, HL60, Jurkat, Raji), and two innate immune-related epithelial cell lines (A549 derived from lung and AGS from stomach), was examined by RT-PCR and immunohistochemistry. The resting immune cell lines showed weak or no gp-340 mRNA expression; while the two epithelial cell lines expressed gp-340 at much higher level, which was differentially regulated by phorbol myristate acetate (PMA) treatment. In the A549 cells, gp-340 was up-regulated along with the PMA-induced proinflammatory expression of both IL-6 and IL-8. In AGS cells, PMA down-regulation of gp-340 was seen in parallel with an up-regulation of the two mature gastric epithelial specific proteins TFF1 (trefoil factor 1) and TFF2, which are implicated as markers of terminal differentiation. Analysis of the distribution of gp-340, together with the TFFs and SP-D in normal lung and gastric mucosa, supported further our in vitro data. We conclude that the differential regulation of gp-340 in the two epithelial cell lines by PMA indicates that gp-340 s involvement in mucosal defence and growth of epithelial cells may vary at different body locations and during different stages of epithelial differentiation.

The pathology and molecular biology of anal intraepithelial neoplasia: comparisons with cervical and vulvar intraepithelial carcinoma

BACKGROUND

Anal intraepithelial neoplasia (AIN) is a well-described pathological precursor of invasive squamous cell carcinoma which has recently been detected with increasing frequency in immunocompromised patients, particularly those with seropositivity for human immunodeficiency virus (HIV). The epidemiology and natural history of this entity is somewhat unclear, since the overall prevalence in the HIV seronegative population is unknown.

DISCUSSION

There is a clear etiological association between AIN and high-risk human papillomavirus (HPV) subtype infection although there is great variability in HPV DNA detection of cytological and histological material in these patients. It appears that there is an antigen-specific hyporesponsiveness by cytotoxic lymphocytes against HPV peptide sequences or recombinant proteins encoded by oncogenic HPV subtypes in these patients, which is dependent upon the stage of their HIV-associated disease. Although the molecular biology of AIN and cervical or vulvar intraepithelial neoplasia are comparable, in AIN there is less significance of tumor suppressor gene mutations, proto-oncogenic growth factor activation, and genomic instability.

CONCLUSION

Current concepts in the epidemiology and etiology of AIN are discussed, as well as its immunological response in the HIV-positive population, drawing parallels where possible between other HPV-related preinvasive disorders, and concluding with a suggested management protocol

A randomised study of screening for colorectal cancer using faecal occult blood testing: results after 13 years and seven biennial screening rounds

BACKGROUND

Three randomised trials have demonstrated reduction in mortality from colorectal cancer (CRC) by repeated screening with faecal occult blood tests, including the trial presented here, which is the only one still in progress.

AIMS

To evaluate reduction in mortality after seven screening rounds and the possible influence of compliance on mortality from CRC.

METHODS

At Funen in Denmark, random allocation to biennial screening with Hemoccult-II in 30 967 subjects aged 45-75 years and 30,966 controls was performed in 1985 from a population of 137,485 of the same age. Only participants who completed the first screening round were invited for further screening. Colonoscopy was offered if the test was positive. The primary end point was death from CRC, and the 10 year results were published in 1996.

RESULTS

From the beginning of the first screening to the seventh round, mean age increased from 59.8 to 70.0 years in the screening and control groups, and the male/female ratio decreased from 0.92 to 0.81. Those who accepted screening were younger than non-responders. Positivity rates varied from 0.8% to 3.8%, the cumulative ratio of a positive test was 5.1% after seven rounds, and 4.8% of patients had at least one colonoscopy. Mortality from CRC was significantly less in the screening group (relative risk (RR) 0.82 (0.69-0.97)), and the reduction in mortality was most pronounced above the sigmoid colon. After seven rounds, RR was reduced to less than 0.70 compared with controls. Mortality rates from causes other than CRC did not differ. Non-responders had a significantly increased risk of death from CRC compared with those who accepted the full programme. Subjects who accepted the first screening, but not subsequent ones, demonstrated a tendency towards increased risk.

CONCLUSIONS

The persistent reduction in mortality from CRC in a biennial screening program with Hemoccult-II, and a reduction in RR to less than 0.70 in those adhering to the programme, support attempts to introduce larger scale population screening programmes. The smaller effect on mortality from CRC in the rectum and sigmoid colon suggests evaluation by additional flexible sigmoidoscopy with longer intervals.

Assessments of clonal composition of colorectal adenomas by FISH analysis of chromosomes 1, 7, 13 and 20

Chromosome banding analysis has shown that numerical aberrations, in particular gains of chromosomes 7, 13 and 20, are common in colorectal adenomas but cannot provide reliable information on the size of the abnormal clones in vivo. We examined interphase nuclei from 70 colorectal adenomas, of which 64 had been previously karyotyped, using fluorescence in situ hybridization (FISH) with probes for the pericentromeric regions of chromosomes 1, 7, 13 and 20. Gain of chromosome 7 was seen in 34% of the analyzed adenomas, +13 was seen in 44% and trisomy 20 was found in 32% of the adenomas, verifying that the trisomies are in vivo phenomena. The median proportion of cells with trisomy was larger than 50%. A comparison with the G-banding analysis showed a good correlation between the results yielded by the 2 methods. Based on the clonal size and karyotypic findings, a likely order of events during clonal evolution could be ascribed to each case. More than 1 numerical aberration was detected by FISH analysis in 16 adenomas. In 6 adenomas, a clone with only trisomy 7 was present alongside a clone with additional gain(s) of chromosomes 13 and/or 20. Seven cases had gain of chromosome 13 and/or gain of chromosome 20 in the largest clone, suggesting that a clone with either of these changes was present before the changes in chromosome 7 copy number took place. On the basis of the results of this combined meta- and interphase cytogenetic study, we conclude that gains of chromosomes 7, 13 and 20 are common in colorectal adenomas and that the trisomies usually are present in a large proportion of the cells. They seem to be primary chromosome aberrations in some adenomas, whereas in others they arise secondarily as part of the clonal evolution. Although the first gain usually is of chromosome 7, it is evident that it is the end result of the chromosomal aberrations, not the exact sequence in which they occur, that determines the pathogenetic consequences.

[Diagnostic benefit of gastrointestinal endoscopy in infants under one year of age--a two-year survey]

INTRODUCTION

Gastrointestinal endoscopy in children is a well-established procedure. We reviewed our experience of endoscopy in infants below one year of age to evaluate indications, endoscopic findings, histology, and complications.

MATERIAL AND METHODS

Twenty-eight infants were studied over a two-year period. Of these, 18 underwent upper endoscopy, six recto/sigmoidoscopy or colonoscopy, and four both procedures.

RESULTS

The most common indication (10/22) for upper endoscopy was vomiting and suspicion of gastrooesophageal reflux disease. In these infants, 24-hour continuous monitoring of the oesophageal pH followed the procedure. Indications for lower endoscopy were rectal bleeding (n = 6) and intractable diarrhoea (n = 4). There were no complications to anaesthesia, endoscopy, or biopsy. Overall, there were endoscopic abnormalities in 82% and histological abnormalities in 75% of the infants. The diagnostic findings included rare disorders, such as eosinophilic gastroenteritis, microvillous inclusion disease, and chylomicron retention disease. Diagnosis of these diseases requires gastrointestinal biopsy.

DISCUSSION

Gastrointestinal endoscopy is a safe procedure, which is a valuable part of the diagnostic work-up in a selected group of infants with long-lasting or severe gastrointestinal symptoms.

[Celiac disease with subepithelial deposition of collagen]

In 1970 a case of malabsorption with flat small intestinal mucosa with subepithelial collagen deposition was described. There was no response to a gluten-free diet, and the condition was termed collagenous sprue. We report a case of coeliac disease with subepithelial deposition of collagen in duodenal biopsy, which responded to a gluten-free diet.

Anal cancer subtype reproducibility study

For histological subtyping of anal squamous carcinomas the WHO advocates a six-way subdivision, but it has been suspected that the six types cannot be reliably discriminated in practice. We conducted a blinded study involving slides from 103 consecutive cases, each slide being examined by three experts (from Denmark, Australia and UK) on two occasions at least 8 months apart. Agreement on subtypes was low: 72% between rounds within pathologist, 61% between pathologists. Even for the commonest, and most stably diagnosed, type, viz. large-cell keratinising squamous carcinoma, the intra- and interpathologist frequencies of confirmation were only 81% and 71%, respectively. The pathologist marked the picture as typical and his subtype diagnosis as certain 41% of times: even then confirmation frequencies were only 88% and 74%, respectively. Calculations, including kappa analyses, suggest that 26% of the typing variation was noise. The WHO scheme must be even more unreliable in everyday practice. We finally mention a recently demonstrated link between human papilloma virus (HPV) and certain types of anal cancer, which may well provide an additional argument for revising existing subtyping schemes.

Review of colorectal cancer and its metastases in rodent models: comparative aspects with those in humans

BACKGROUND AND PURPOSE

Colorectal cancer (CRC) remains one of the most common cancer forms developing in industrialized countries, and its incidence appears to be rising. Studies of human population groups provide insufficient information about carcinogenesis, pathogenesis, and treatment of CRC. To study these phenomena in detail, a number of animal models of human CRC have been developed. The hypothetical ideal animal model should mimic the human disease in terms of morphology, biochemical alterations, and biological behavior. No existing model replicates the disease as an entity, but available models approximate many of the characteristics of human colonic carcinogenesis and metastasis. So far few comparative evaluations of the various animal models of CRC have been made.

CONCLUSION

Animal studies cannot replace human clinical trials, but they can be used as a pre-screening tool, so that human trials become more directed, with greater chances of success. The orthotopic transplantation of colon cancer cells into the cecum of syngeneic animals or intraportal inoculation appears to resemble the human metastatic disease most closely, providing a model for study of the treatment of metastases. Which model(s) to choose depends on the goal(s) of the experiment(s). The review published here can provide help in selecting the most optimal CRC model(s) for a certain purpose and in preventing unnecessary duplication of animal experimentation.

Clinical evidence for the adenoma-carcinoma sequence

A review is given on evidence supporting or rejecting the hypothesis of a colorectal adenoma-carcinoma sequence. The majority of studies discuss adenomas from a clinical point of view, but pathology has also been considered in detail, and molecular biology has been touched on. It is concluded the adenoma stage is, most probably, a phase on the way to carcinoma. But it remains to be shown what effect the removal of adenomas will have in the long run on the incidence of colorectal carcinoma.

Choice of management strategy for colorectal cancer based on a diagnostic immunohistochemical test for defective mismatch repair

BACKGROUND

Despite intensive research into the molecular abnormalities associated with colorectal cancer (CRC), no diagnostic tests have emerged which usefully complement standard histopathological assessments.

AIMS

To assess the feasibility of using immunohistochemistry to detect replication error (RER) positive CRCs and determine the incidence of RER positivity within distinct patient subgroups.

METHODS

502 CRCs were analysed for RER positivity (at least two markers affected) and/or expression of hMSH2 and hMLH1.

RESULTS

There were 15/30 (50%) patients with metachronous CRCs, 16/51 (31%) with synchronous CRCs, 14/45 (31%) with a proximal colon carcinoma, and 4/23 (17%) who developed a CRC under the age of 50 showed RER positivity. However, 0/54 patients who developed a solitary carcinoma of the rectum/left colon over the age of 50 showed RER positivity. Immunohistochemical analysis revealed that 66/66 (100%) RER positive carcinomas were associated with complete lack of expression of either hMSH2 or hMLH1. This correlation was confirmed using a further 101 proximal colon carcinomas. Patients with a mismatch repair defective carcinoma showed improved survival but a 5.54 times relative risk of developing a metachronous CRC. A prospective immunohistochemical study revealed 13/117 (11%) patients had a mismatch repair defective carcinoma. A fivefold excess of hMLH1 defective cases was noted.

CONCLUSIONS

All RER positive carcinomas were identified by the immunohistochemical test. This is the first simple laboratory test which can be performed routinely on all CRCs. It will provide a method for selecting patients who should be investigated for HNPCC, offered long term follow up, and who may not respond to standard chemotherapy regimens.

The expression of p53, Ki-67 and urokinase plasminogen activator receptor in colorectal adenomas with true invasion and pseudoinvasion

The recognition of pseudoinvasion is important in the differential diagnosis of adenocarcinoma in patients with adenomas. This distinction might occasionally be difficult, particularly when the dysplasia is pronounced. The present study was undertaken in order to investigate whether the immunohistochemical expression of p53, Ki-67 and the urokinase plasminogen activator receptor (uPAR) was different in adenomas with true invasion and pseudoinvasion. We studied 26 formalin-fixed, paraffin-embedded tumor samples, consisting of 10 cases of adenomas with pseudoinvasion and 16 cases of adenocarcinomas in adenomas. In this series of selected histologically typical cases a constant moderate or strong reaction for uPAR was present at the invasive front in all of the 16 adenomas with adenocarcinoma, but only focally in one of 10 adenomas with pseudoinvasion. The reactions for p53 and Ki-67 showed only minor differences. In conclusion, the immunohistochemical reaction for uPAR seems to be a useful supplement in cases without typical histology or with severe dysplasia.

Variants of squamous cell carcinoma of the anal canal and perianal skin and their relation to human papillomaviruses

High-risk types of human papillomaviruses (hrHPVs) may be a necessary cause in cervical cancer and in some subtype of anal, vulvar, and penile cancers. Large studies aimed at characterizing hrHPV-associated and non-hrHPV-associated subtypes of anal carcinomas are, however, lacking. We searched for human papillomavirus type 16 and 13 other hrHPVs in tumor tissue by PCR and performed a systematic histological evaluation of specimens from 386 patients with anal cancer (86% invasive; 302 women and 84 men). Cancers in women and homosexual men were more often hrHPV positive (P < 0.01) and located in the anal canal (P < or = 0.01) than were cancers in heterosexual men. In both women and men, anal canal cancers contained hrHPV clearly more often than did perianal skin cancers, and increasing hrHPV positivity was seen with higher localization in the anal canal. Indeed, 95 and 83% of cancers involving the anal canal in women and men, respectively, were hrHPV positive versus 80 and 28% of perianal skin cancers (P-trend < 0.001). Basaloid feature, adjacent anal intraepithelial neoplasia, poor or absent keratinization, and a predominance of small or medium neoplastic cells were all strongly positively associated with hrHPV status. Like cancer of the uterine cervix, the development of cancer of the anal canal may require infection with hrHPV, whereas a dual etiology of perianal skin cancers bears parallels to vulvar and penile cancers.

Possible advantages and drawbacks of adding flexible sigmoidoscopy to hemoccult-II in screening for colorectal cancer. A randomized study

BACKGROUND

Flexible sigmoidoscopy (FS) has been recommended as a screening method to reduce mortality from colorectal cancer (CRC). The present study evaluates the effect of adding FS to the fecal occult blood test Hemoccult-II (H-II) on diagnostic yield of colorectal neoplasia.

METHODS

A total of 10,978 normal persons aged 50-75 years were invited to participate, 5495 persons being allocated at random to H-II and FS and 5483 to H-II alone.

RESULTS

In spite of a lower compliance (40% versus 56%) for the combined procedure, the diagnostic yield of colorectal neoplasia was higher than for H-II alone (12 CRC versus 4 CRC, and 72 large adenomas versus 14). Within 24-62 months after screening there were fewer CRCs detected after H-II + FS than after H-II alone. The stage distribution was less favorable than in screen-detected cases.

CONCLUSION

One FS may not be an optimal way of screening, but FS deserves to be evaluated in randomized population studies including repeated H-II tests in the control arm.

Cytogenetic analysis of colorectal adenomas: karyotypic comparisons of synchronous tumors

The phenotypic progression of colorectal tumors is driven by their step-by-step acquisition of genomic alterations. These pathogenetically important mutations are at the same time markers of tumor clonality. The aim of this study was to describe the clonal relation among synchronous colorectal adenomas. Twenty-four colorectal adenomas from 11 patients were subjected to chromosome banding analysis. Clonal chromosome abnormalities were found in 20 tumors. Recurrent structural rearrangements involved chromosomes 1, 13, 17, and 18. The most common numerical changes were gain of chromosomes 7, 13, 20, and 3 and loss of chromosome 18. Eight adenomas had subclones as evidence of clonal evolution. Similar clones in separate polyps were seen in tumors from 6 patients; these adenomas were always located in the same part of the large bowel. In 2 patients, both with one rectal adenoma and one adenoma in the colon, no karyotypic similarity between the lesions was found. Our findings indicate that whereas close, but macroscopically distinct, synchronous colorectal adenomas usually have a common pathway of progression, perhaps even the same clonal origin, large bowel adenomas at a considerable distance from one another exhibit karyotypic differences, indicating that they arise independently.

Immunisation of colorectal cancer patients with autologous tumour cells

Patients with colorectal cancer were entered into a clinical phase I trial of immunotherapy with an autologous tumour cell/bacillus Calmette-Guerin (BCG) vaccine. We attempted to describe the possible effects and side effects of the immunisation, and further to investigate whether expression of immune-response-related surface molecules on the tumour cells in the vaccine correlated with survival. The first and second vaccine comprised of 107 irradiated tumour cells mixed with BCG, the third of irradiated tumour cells only. Thirty-nine patients were considered, but only 6 patients fulfilled the criteria for inclusion. No serious side effects were observed. With three years of observation time, two patients are healthy, while the rest have had recurrence, and two of them have died. In all vaccines, all tumour cells expressed HLA class I, some expressed HLA class II and none expressed CD80. There was an inverse relation between survival and HLA class II expression. This highlights an essential problem, in the absence of CD80 expression the expression of HLA class II may induce anergy. In future attempts to develop improved vaccines this problem should be addressed.

Flow cytometric investigation of immune-response-related surface molecules on human colorectal cancers

Our purpose was to clarify whether human colorectal cancer cells are equipped to present tumour-associated-antigens to the immune system, and whether this ability correlates with lymphoid infiltration, the Dukes' stage and Jass classification. Enzymatically dissociated tumour cells from 70 different colorectal cancers were monitored by multiparameter flow cytometry. Gating on EP4+ cells, the expression of the surface molecules HLA class I, HLA class II, CD80 (B7-1), CD54 (ICAM-I) and CD58 (LFA-3) was evaluated. In 60 of 70 tumours, all tumour cells expressed HLA class I, in 10 tumours 15-96% of the tumour cells expressed HLA class I. In 1 tumour, all tumour cells expressed HLA class II, in 67 tumours some expressed HLA class II, in 2 tumours none expressed HLA class II. Expression of CD58 was heterogeneous, and there was no or only sparse expression of CD80 and CD54. Expression of the HLA class I molecules, but not the class II, was correlated with lymphoid infiltration and the Jass classification. Expression of these surface molecules was not correlated with the Dukes' stage. The tumour cells were generally equipped to present antigens to the effector arm of the immune system since HLA class I is expressed, but the tumour cells were not optimal in stimulating an immune response, since HLA class II and CD58 were only marginally expressed and CD80 and CD54 were absent.

A comparison of flow cytometry and immunohistochemistry in human colorectal cancers

In human colorectal cancer it has been reported that some tumours lack the HLA-ABC antigens. This has been interpreted as reflecting tumour escape from the immune system. Earlier data have been obtained by immunohistochemistry. In this study, we compared the expression of HLA-ABC, HLA-DR, CD80 (B7-1) and CD54 (ICAM-1) in 20 tumours using both a conventional immunohistochemistry two-layer technique and multiparameter flow cytometry, gating on an epithelial cell marker. Colorectal cancer tissue used in flow cytometry was dissociated with collagenase, deoxyribonuclease and hyaluronidase. The intensity of expression of HLA-ABC, HLA-DR and CD80 was unaffected by the enzymes, but CD54 was decreased by 30%. The reproducibility of flow cytometry was good. Microscopy of sections revealed that about 5% of each tumour sample consisted of normal epithelium, but even after correction for this, flow cytometry was superior to immunohistochemistry in 33 out of 80 cases, and showed that tumours described as HLA-ABC negative by immunohistochemistry were in fact weakly positive for HLA-ABC. We conclude that flow cytometry and immunohistochemistry are complementary, and that flow cytometry is superior to immunohistochemistry for detecting antigens/epitopes present in low amounts.

Allelic imbalance and cytogenetic deletion of 1p in colorectal adenomas: a target region identified between DIS199 and DIS234

Both cytogenetic and molecular genetic analyses have shown that many colorectal adenomas carry an acquired deletion distally in the short arm of one chromosome 1, but the two methods have never been brought to bear on the same tumors. The major part of this study was the analysis of 53 previously short-term cultured and karyotyped colorectal adenomas for allelic imbalance at eight microsatellite loci in 1p. Allelic imbalances were detected in seven of the 12 adenomas that had cytogenetically visible abnormalities of chromosome 1, as well as in four adenomas that either had a normal karyotype (one case) or had clonal chromosome abnormalities that did not seem to involve chromosome 1 (three cases); i.e., 30% of the adenomas had abnormalities involving 1p by the combined approach. A minimal region of overlap seemed to map to between DIS199 and DIS234, suggesting that this is a relevant target region. This genomic area contains the human homologue of the tumor modifier gene Mom1 (1p35-36.1), which, in mice, modifies the number of intestinal tumors in multiple intestinal neoplasia (Min)-mutated animals. To evaluate whether the imbalances corresponded to interstitial deletions of 1p material, we performed fluorescence in situ hybridization with a pericentromeric probe (15 adenomas) and a telomeric probe (6 adenomas) on uncultured cells from the 16 adenomas with chromosome 1 abnormalities. Except for three adenomas that had already been shown by banding analysis to have a trisomic pattern, two centromere 1 signals were invariably found. In the cases hybridized with the 1p-telomeric probe, we found the same frequencies of telomeric and centromeric signals, in agreement with the interpretation that the deletions were interstitial. One of the 53 adenomas had genomic instability, seen as new alleles at five of eight microsatellite loci. A comparison of the genetic findings with clinicopathologic data indicated that adenomas in the rectum have 1p abnormalities more often than do adenomas of the sigmoid colon, and that adenomas with 1p changes are larger than adenomas without abnormalities of chromosome 1.

The pattern of recurrent colorectal cancer in a prospective randomised study and the characteristics of diagnostic tests

In a prospective randomised study, 597 patients subjected to curative surgery for colorectal cancer were allocated to either a group with frequent follow-up or a control group with follow-up every 5 years. The pattern of recurrence is reviewed. An equal number of recurrences was detected in the two groups, but the recurrence was diagnosed 9 months earlier in patients followed frequently, and the diagnostic characteristics of various tests dependent upon how often they were used. It is unlikely that frequent follow-up after curative surgery for colorectal cancer has a large positive influence upon survival, but a small benefit from an intensive follow-up program cannot be ruled out. The present results indicate that clinical examination, digital rectal examination, proctoscopy, colonoscopy and chest x-ray should be included in such a programme, whereas others (blood haemoglobin, faecal occult blood test, double contrast braium enema, serum alanine aminotransferase, and serum bilirubin) should be avoided, having a low sensitivity for detecting recurrent colorectal cancer.

Cytogenetic findings in metastases from colorectal cancer

Eighteen tumor samples from 11 patients with metastatic colorectal cancer were cytogenetically analyzed after short-term culturing. Of the 13 metastases examined, 11 were from lymph nodes, 1 from the peritoneum and 1 from the lung. In 5 of the 11 patients, matched samples from the primary tumor and lymph node metastases were analyzed. Cytogenetic similarities between the primary and secondary lesions were found in all 5 cases, indicating that many of the chromosomal aberrations presumably occurred before disease spreading took place. Compared with the primaries, the metastases appeared to exhibit decreased clonal heterogeneity but, concurrently, an increase in the karyotypic complexity of individual clones. Among the aberrations recurrently found in metastatic lesions were del(1)(p34), i(17)(q10), -18, -Y, -21, +7 and +20, all of which have been seen repeatedly in previous series of primary colorectal carcinomas, and del(10)(q22) and add(16)(p13), which so far have not been associated with primary tumors and which may play a particular pathogenetic role in the metastatic process.

[Randomized population study of screening for intestinal cancer with Hemoccult-II]

The aim of the randomised study was to compare mortality rates from colorectal cancer (CRC) in persons screened with faecal occult-blood tests every two years during a 10-year period with those of unscreened similar controls. Thirty thousand nine hundred and sixty-seven persons aged 45-75 years in 1985 were allocated to screening and another 30,966 to a control group. Only participants who completed the first round with Hemoccult-II were invited for further screening. Participants with positive tests were offered colonoscopy. The primary endpoint was death from CRC. Sixty-seven percent completed the first screening round, and of these more than 90% accepted repeated screenings. During the 10 year study, 481 persons in the screening group had a diagnosis of CRC, compared with 483 unscreened controls. CRC mortality was significantly lower in the screening group (205 deaths) than in controls (249 deaths) (mortality ratio 0.82 [95% conf. lim. 0.68-0.99], p = 0.03). Our findings indicate that biennial screening by faecal occult-blood tests can reduce CRC mortality.

Cytogenetic findings in metastases from colorectal cancer

Eighteen tumor samples from 11 patients with metastatic colorectal cancer were cytogenetically analyzed after short-term culturing. Of the 13 metastases examined, 11 were from lymph nodes, 1 from the peritoneum and 1 from the lung. In 5 of the 11 patients, matched samples from the primary tumor and lymph node metastases were analyzed. Cytogenetic similarities between the primary and secondary lesions were found in all 5 cases, indicating that many of the chromosomal aberrations presumably occurred before disease spreading took place. Compared with the primaries, the metastases appeared to exhibit decreased clonal heterogeneity but, concurrently, an increase in the karyotypic complexity of individual clones. Among the aberrations recurrently found in metastatic lesions were del(1)(p34), i(17)(q10), -18, -Y, -21, +7 and +20, all of which have been seen repeatedly in previous series of primary colorectal carcinomas, and del(10)(q22) and add(16)(p13), which so far have not been associated with primary tumors and which may play a particular pathogenetic role in the metastatic process.

A prospective randomized study of follow-up after radical surgery for colorectal cancer

BACKGROUND

The possible benefit for patients from follow-up examinations after curative surgery for colorectal cancer is unproven. The purpose of this study was to determine whether survival is improved by frequent follow-up examinations.

METHODS

A total of 597 patients less than 76 years old treated with radical surgery for colorectal cancer were included in the study from 1983 to 1994. Patients were randomized to frequent follow-up (group 1) or virtually no follow-up (group 2) with examinations at 5 and 10 years.

RESULTS

Group 1 comprised 290 patients, group 2 contained 307. Recurrence was equally frequent (26 per cent), but the time of diagnosis was 9 months earlier in group 1; also, more recurrences were asymptomatic in group 1 and more patients had new surgery with curative intent (P = 0.02). However, no improvement in overall survival or in cancer-related survival resulted.

CONCLUSION

Patients subjected to intensive follow-up have recurrence diagnosed earlier, and have more operations for recurrence, but the survival results suggest that any major improvement by intensive follow-up is unlikely.

A prospective randomized study of follow-up after radical surgery for colorectal cancer

BACKGROUND

The possible benefit for patients from follow-up examinations after curative surgery for colorectal cancer is unproven. The purpose of this study was to determine whether survival is improved by frequent follow-up examinations.

METHODS

A total of 597 patients less than 76 years old treated with radical surgery for colorectal cancer were included in the study from 1983 to 1994. Patients were randomized to frequent follow-up (group 1) or virtually no follow-up (group 2) with examinations at 5 and 10 years.

RESULTS

Group 1 comprised 290 patients, group 2 contained 307. Recurrence was equally frequent (26 per cent), but the time of diagnosis was 9 months earlier in group 1; also, more recurrences were asymptomatic in group 1 and more patients had new surgery with curative intent (P = 0.02). However, no improvement in overall survival or in cancer-related survival resulted.

CONCLUSION

Patients subjected to intensive follow-up have recurrence diagnosed earlier, and have more operations for recurrence, but the survival results suggest that any major improvement by intensive follow-up is unlikely.

Amantadine and equine influenza: pharmacology, pharmacokinetics and neurological effects in the horse

Amantadine is an antiviral agent effective against influenza A viruses. We investigated 1) the antiviral efficacy, 2) analytical detection, 3) bioavailability and disposition, 4) pharmacokinetic modelling and 5) adverse reactions of amantadine in the horse. In vitro, amantadine and its derivative rimantadine suppressed the replication of recent isolates of equine-2 influenza virus with effective doses (EDs) of less than 30 ng/ml. Rimantadine was more effective than amantadine against most viral isolates; we suggest a minimum plasma concentration of 300 ng/ml of amantadine for therapeutic efficacy. In vivo an i.v. dose of amantadine 15 mg/kg bwt produced mild, transient CNS signs which were no longer apparent after 30 min. Amantadine administered at a dose of 15 mg/kg bwt was established as the maximum safe single i.v. dose. However, if repeated i.v. administration of amantadine is required no more than 10 mg/kg bwt t.i.d. should be used. The maximal safe plasma concentration of amantadine was not evaluated but is probably greater than 2000 ng/ml and possibly greater than 4000 ng/ml. On the other hand, horses with lower seizure thresholds, or those on medications that lower seizure thresholds, may be at increased risk of amantadine-induced seizures, which show few premonitory signs and are rapidly fatal. After i.v. administration of amantadine 10 mg/kg bwt, the disposition kinetics were well fitted by a 2-compartment open model. The estimated peak plasma concentration after this dose was about 4500 ng/ml, the volume of distribution at steady-state (Vdss) was (mean +/- s.d.) 4.9 +/- 1.9 l/kg bwt and the beta phase half-life was 1.83 +/- 0.87 h. Computer projections of plasma amantadine concentrations after i.v. administration of amantadine at a dose of 10 mg/kg bwt t.i.d. at 8 h intervals suggest peak plasma concentrations of 4000-5000 ng/ml and troughs of less than 300 ng/ml will be achieved. Amantadine administered orally at 10 mg/kg bwt and 20 mg/kg bwt showed mean oral bioavailability of about 40-60% and a plasma half life of 3.4 +/- 1.4 h; however, there was substantial inter-animal variation in bioavailability. Projections based on the kinetics observed in individual animals suggest that some animals readily maintain effective plasma concentrations of amantadine after oral administration of 20 mg/kg bwt t.i.d. On the other hand, animals in which amantadine is poorly bioavailable may require up to a 6-fold (120 mg/kg bwt) increase in the oral dose to achieve effective blood concentrations. Withholding food for 15 h did not reduce these inter-animal differences in bioavailability. Our results showed that simple dosing with oral amantadine will not yield effective plasma concentrations in all animals. While i.v. administration yielded more reproducible plasma concentrations, care should be taken to see that the seizure threshold is not exceeded. In acute situations, i.v. administration (5 mg/kg bwt) every 4 h should maintain safe and effective plasma and respiratory tract concentrations of amantadine.

[Reversible liver steatosis in patients treated with 5-fluorouracil and interferon-alpha]

Twenty-three patients with metastatic colorectal carcinoma were randomized as part of two multicenter Phase III trials to receive either 5-fluorouracil (5-FU)/interferon alpha-2A (INF-alpha) or 5-FU +/- leucovorin. The patients were evaluated regularly for response by CT of the abdomen when treatment began and then every six to eight weeks. incidentally, we found that four of 13 patients treated with 5-FU/INF-alpha and none of ten patients treated with 5-FU +/- leucovorin developed hepatic steatosis during treatment. The diagnoses were based on a decreased CT value of the liver parenchyma by the repeated CT, and histologically verified by liver biopsies. There was no relationship to cumulative 5-FU or INF-alpha dose. Based on posttreatment CT, the liver parenchyma changes were reversible after therapy was stopped. Recognition of this condition in patients receiving 5FU/INF-alpha is important to prevent a patient from being labeled as having progressive hepatic metastases.

Randomised study of screening for colorectal cancer with faecal-occult-blood test

BACKGROUND

Case-control studies and a voluntary-based follow-up study have suggested that repeated screening with faecal-occult-blood (FOB) tests can lead to a reduction in mortality from colorectal cancer (CRC). The aim of this randomised study was to compare mortality rates after FOB tests every 2 years during a 10-year period with those of unscreened similar controls.

METHODS

140,000 people aged 45-75 years lived in Funen, Denmark, in August, 1985, and were considered for inclusion in our study. Before randomisation we excluded individuals who had CRC or precursor adenomas and those who had taken part in a previous pilot study. Randomisation of 137,485 people in blocks of 14 allocated three per 14 to the screening group (30,967), three per 14 to the control group (30,966), and eight not to be enrolled in the study (75,552). Controls were not told about the study and continued to use health-care facilities as normal. Hemoccult-II blood tests (with dietary restrictions but without rehydration) were sent to screening-group participants. Only those participants who completed the first screening round were invited for further screening--five rounds of screening during a 10-year period. Participants with positive tests were asked to attend to full examination and were offered colonoscopy whenever possible. The primary endpoint was death from CRC.

FINDINGS

Of the 30,967 screening-group participants, 20,672 (67%) completed the first screening round and were invited for further screening; more than 90% accepted repeated screenings. During the 10-year study, 481 people in the screening group had a diagnosis of CRC, compared with 483 unscreened controls. There were 205 deaths attributable to CRC in the screening group, compared with 249 deaths in controls. CRC mortality, including deaths attributable to complications from CRC treatment, was significantly lower in the screening group than in controls (mortality ratio 0.82 [95% CI 0.68-0.99]) p = 0.03).

INTERPRETATION

Our findings indicate that biennial screening by FOB tests can reduce CRC mortality. This study is being continued to improve its statistical power and to assess the effect of the removal of more precursor adenomas in the screening-group participants than in controls on CRC incidence.

Chromosome abnormalities in colorectal adenomas: two cytogenetic subgroups characterized by deletion of 1p and numerical aberrations

Cytogenetic analysis of short-term cultures from 34 benign colorectal polyps, all histologically verified as adenomas, revealed clonal chromosome aberrations in 21 of them. Eight polyps had structural rearrangements, whereas only numerical changes were found in 13. A combination of structural and numerical chromosomal aberrations was found in three polyps. The most common numerical change was gain of chromosome 7, found either as the sole anomaly (five polyps), together with other numerical changes (six polyps), or together with structural rearrangements (two polyps). Other recurrent numerical changes were +20, +13, and monosomy 18, found in six, five, and two adenomas, respectively. Rearrangement of chromosome 1 was the most common structural change. Abnormalities involving 1p were seen in six adenomas, leading to visible loss of material in three. One adenoma had one clone with a large and another with a small 1p deletion. In three adenomas, del(1)(p36) was the only cytogenetic aberration, supporting the authors' previous conclusion that loss of one or more gene loci in band 1p36 is a common early change in colorectal tumorigenesis. Chromosome 8 was involved in structural changes in two adenomas; in one this led to loss of 8p and in the other to gain of 8q. The cytogenetic findings did not correlate in a statistically significant manner with clinicopathologic parameters, such as grade of dysplasia, macroscopic or microscopic adenoma structure, tumor size and location, or the patients' sex and age.

[Intraoperative ultrasonography in colorectal cancer. A prospective, blind study]

This study was designed to compare diagnostic accuracies of measuring liver enzymes, preoperative ultrasonography, surgical examination, and intraoperative ultrasonography for detection of liver metastases from colorectal cancer. A blind prospective comparison between the diagnostic examinations mentioned above were performed in 295 consecutive patients with colorectal cancer. An experienced ultrasonologist performed the preoperative examinations and the results were not known to the other experienced ultrasonologist, who did the intraoperative examinations. The latter was also unaware of the findings by the surgeon. The presence of metastases was further assessed by ultrasonography three months postoperatively, as well as surgery and liver biopsy in some of the patients. The sensitivity of intraoperative ultrasonography (62/64) was significantly superior to that of surgical exploration (54/64), and that of preoperative ultrasonography (45/64). The lowest sensitivity was presented by liver enzymes. "Bilobar" metastases were detected in 42 of 46 patients by intraoperative ultrasonography, but in no more than 33 by the surgeon. Intraoperative ultrasonography demonstrated the highest specificity of all examinations. Intraoperative ultrasonography reduces the number of patients with liver metastases being subjected to superfluous or even harmful liver surgery and it may increase the number in whom liver surgery will prolong life.