Retrospective study on Escherichia coli infection in broilers subjected to postmortem examination and antibiotic resistance of isolates in Trinidad

An 8-yr retrospective study was conducted to evaluate the rate of Escherichia coli infection and antibiotic resistance of isolates from diseased broilers submitted for diagnosis in Trinidad from 1990 to 1997. Of a total of 906 cases of diseased birds subjected to postmortem examination, 603 (66.6%) had E. coli infection. The number of cases increased over the years from 16 in 1990 to a peak of 294 in 1996. For every year, at least 50% of all broiler cases had E. coli infection. The rate of infection was significantly higher during the rainy season (74.1 +/- 6.9%) than during the dry season (57.8 +/- 7.0%). Approximately 50% of all E. coli isolates were resistant to 9 out of a total of 11 antimicrobial drugs selected for the study. The isolates showed an increasing trend of resistance to amoxicillin, apramycin, gentamicin, nitrofurantoin, norfloxacin, and sulfamethoxazole-trimethoprim. However, only the trends of resistance to apramycin and norfloxacin were statistically significant. Overall, of the antimicrobial drugs selected, norfloxacin relatively appeared as the best choice for treatment. From this study, we conclude that the high rate of E. coli infection in broilers submitted for diagnosis along with the high resistance of isolates to antimicrobial drugs constitute a threat to the poultry industry on the island.

Small, efficient hammerhead ribozymes

The hammerhead ribozyme is able to cleave RNA in a sequence-specific manner. These ribozymes are usually designed with four basepairs in helix II, and with equal numbers of nucleotides in the 5' and 3' hybridizing arms that bind the RNA substrate on either side of the cleavage site. Here guidelines are given for redesigning the ribozyme so that it is small, but retains efficient cleavage activity. First, the ribozyme may be reduced in size by shortening the 5' arm of the ribozyme to five or six nucleotides; for these ribozymes, cleavage of short substrates is maximal. Second, the internal double-helix of the ribozyme (helix II) may be shortened to one or no basepairs, forming a miniribozyme or minizyme, respectively. The sequence of the shortened helix + loop II greatly affects cleavage rates. With eight or more nucleotides in both the 5' and the 3' arms of a miniribozyme containing an optimized sequence for helix + loop II, cleavage rates of short substrates are greater than for analogous ribozymes possessing a longer helix II. Cleavage of gene-length RNA substrates may be best achieved by miniribozymes.

Monocytically differentiating HL60 cells proliferate rapidly before they mature

1alpha,25-Dihydroxyvitamin D(3) (D(3)) provokes growth arrest and monocytic differentiation in myeloid cells. Although it is usually assumed that the cellular events leading to growth arrest start within one cell cycle of D(3) addition, there is also evidence that D(3) provokes the expression of proliferation-related genes and accelerates cell division. Herein we clarify the relationship between proliferation and maturation in differentiating HL60 cells. Cells were cultured singly, D(3) was added at various stages of the cell cycle, the progeny were counted, and the proportions of mature monocytes were determined. Initially, the D(3)-treated cells proliferated at an accelerated rate, and they matured only later. If cells encountered D(3) early in G1 they divided two to four times before maturing, and if they encountered D(3) later in the cell cycle they underwent an extra division. Indomethacin slows HL60 cell multiplication by prolonging G1, and when these slower-growing cells were exposed to D(3), they matured after the usual period but underwent one division less than indomethacin-free cells. Contrary to common assumptions, we conclude that promyeloid cells do not initiate growth arrest or monocytic maturation immediately after exposure to D(3). Instead, an encounter with D(3) early in G1 sets in train a complex differentiation program. This consists of 2-3 days of rapid proliferation-probably employing cell cycles with a shortened G1 phase-that is followed by growth arrest and maturation. As a result, a single D(3)-treated promyeloid cell gives rise to 10 or more mature monocytes. These observations not only explain why "differentiating" cells express proliferation-related characteristics soon after D(3) addition, but they also show that the process of D(3)-induced monocytic differentiation is much more complex than has previously been realized.

Disruption of operant oral self-administration of ethanol, sucrose, and saccharin by the AMPA/kainate antagonist, NBQX, but not the AMPA antagonist, GYKI 52466

BACKGROUND

AMPAergic transmission has been suggested to be important in mediating the rewarding effects of drugs. We therefore examined the role of non-NMDA glutamate-receptors in mediating the reinforcing properties of ethanol in an oral self-administration paradigm.

METHODS

The competitive antagonist NBQX (2,3-dihydroxy-6-nitro-7-sulfamoylbenzo(f)quinoxaline) and the non-competitive antagonist, GYKI 52466 (1-(4-aminophenyl)-4-methyl-7,8-methylene-dioxy-5H2,3- be nzodiazepine), were administered to animals previously trained to self-administer ethanol, sucrose, or saccharin, on a progressive ratio schedule.

RESULTS

GYKI 52466 (5 & 10 mg/kg) had no effect on operant responding for ethanol, but increased spontaneous locomotor activity, whereas the highest doses of NBQX (3 & 6 mg/kg) significantly decreased operant responding and correspondingly decreased the breaking point in responding for ethanol on a progressive ratio schedule. NBQX (but not GYKI 52466) also significantly decreased operant responding for a food reinforcer (sucrose) as well as for a sweet tasting reinforcer (saccharin). Doses of NBQX that disrupted operant performance caused a significant reduction in locomotor activity, indicating that NBQX decreased ethanol self-administration only at doses which disrupt motor activity.

CONCLUSIONS

These results suggest non-NMDA glutamate-receptors may not have a specific role in the maintenance of responding for an ethanol reinforcer, but may generally disrupt operant performance. Because, unlike GYKI 52466, NBQX possesses an action at central kainate receptors, these results suggest that kainate, but not AMPA (alpha-amino 3-hydroxy-5-methyl-4-isoxazole propionate) receptors may be important in mediating the reinforcing effects of ethanol.

Evolution of speckle during spinodal decomposition

Time-dependent properties of the speckled intensity patterns created by scattering coherent radiation from materials undergoing spinodal decomposition are investigated by numerical integration of the Cahn-Hilliard-Cook equation. For binary systems which obey a local conservation law, the characteristic domain size is known to grow in time tau as R=[Btau](n) with n=1/3, where B is a constant. The intensities of individual speckles are found to be nonstationary, persistent time series. The two-time intensity covariance at wave vector k can be collapsed onto a scaling function Cov(deltat,t), where deltat=k(1/n)B(tau(2)-tau(1)) and t=k(1/n)B(tau(1)+tau(2))/2. Both analytically and numerically, the covariance is found to depend on deltat only through deltat/t in the small-t limit and deltat/t (1-n) in the large-t limit, consistent with a simple theory of moving interfaces that applies to any universality class described by a scalar order parameter. The speckle-intensity covariance is numerically demonstrated to be equal to the square of the two-time structure factor of the scattering material, for which an analytic scaling function is obtained for large t. In addition, the two-time, two-point order-parameter correlation function is found to scale as C(r/(B(n)sqaureroot[tau1(2n)+tau2(2n)]),tau1/tau2), even for quite large distances r. The asymptotic power-law exponent for the autocorrelation function is found to be lambda approximately 4.47, violating an upper bound conjectured by Fisher and Huse.

An automated radiosynthesis of 2-[11C]thymidine using anhydrous [11C]urea derived from [11C]phosgene

2-[11C]Thymidine has been produced from [11C]methane via [11C]phosgene and [11C]urea. Anhydrous [11C]urea was prepared from [11C]phosgene by reaction with liquid ammonia. This novel approach avoids the problems associated with the synthesis of anhydrous [11C]urea from [11C]cyanide. A fully automated system based on a modular approach and under PLC control has been developed. The system provides 2-[11C]thymidine reliably and reproducibly for clinical PET studies. The radiosynthesis takes 45-50 min from [11C]methane and the average yield was 1.5-3.3 GBq (40-90 mCi). The specific radioactivity was typically in the range 29.6-51.8 GBq mumol-1 (0.8-1.4 Ci mumol-1) at EOS corresponding to 6-12 micrograms of stable thymidine. The radiochemical yield of 2-[11C]thymidine was ca. 14% from [11C]methane.

Inhibition of mitochondrial function in HL60 cells is associated with an increased apoptosis and expression of CD14

The myelomonocytic cell line HL60 can be induced by a variety of chemical agents to differentiation to either neutrophils or monocytes. Examination of gene expression, by differential display, in cells induced to monocytes with 1alpha,25-dihydroxyvitamin D(3) or neutrophils with all-trans retinoic acid (ATRA) identified a number of clones with altered patterns of expression over the period of differentiation. One of these clones was the mitochondrial gene NADH dehydrogenase subunit 4 (ND4) which showed a differential pattern of expression between the neutrophil and monocyte lineages. The potential of mitochondrial inhibitors to induce differentiation was investigated by treating the HL60 cells with either the NADH dehydrogenase inhibitor, Rotenone, the complex III inhibitor, Antimycin A, or the highly specific mitochondrial ATP-synthase inhibitor, Oligomycin. Although functional assays of differentiation did not produce any positive results, all the inhibitors resulted in a dramatic increase in CD14 expression at day 1, with CD38 markers not observed until day 3. The increased expression of CD14 was accompanied by a decrease in viability and all CD14 positive cells were also positive for Annexin V, a marker of apoptosis. These results suggest that inhibition of the components of the mitochondrial pathways may lead to the marking of some cells, via CD14, for cell death, whilst allowing commitment to differentiation to occur in the surviving population.

Home-made spacers for bronchodilator therapy in children with acute asthma: a randomised trial

BACKGROUND

A metered-dose inhaler (MDI) with spacer is the best way to deliver bronchodilator therapy for treatment of acute asthma. In developing countries, commercially produced spacers are generally unavailable or too costly. We tested the efficacy of home-made spacers (500 mL plastic bottle, polystyrene cup) compared with a conventional spacer for delivery of a beta2 agonist via MDI for children with acute asthma.

METHODS

We studied children aged 5 to 13 years with acute asthma, stratified into those with mild airways obstruction (peak expiratory flow [PEF] 60-79% of predicted value) or moderate to severe airways obstruction (PEF 20-59% of predicted value). A beta2 agonist (fenoterol hydrobromide) was given via MDI and one of four randomly assigned spacers (conventional spacer, sealed 500 mL plastic bottle, unsealed 500 mL bottle, 200 mL polystyrene cup). Clinical score, pulmonary function tests, and oximetry were recorded at baseline and 15 min after treatment. If a second bronchodilator treatment was needed, nebulised fenoterol was given and the assessment repeated 15 min later. Primary outcome measures were changes in clinical score and pulmonary function, and need for and response to nebulisation.

FINDINGS

88 children were eligible for study. In 44 children with moderate to severe airways obstruction, a cup gave significantly less bronchodilation (median increase in: forced expiratory volume in 1 s [FEV1] 0%; PEF 12%) compared with the conventional spacer (37%; 59%), sealed bottle (33%; 36%), or unsealed bottle (18%; 21%, p<0.05 for difference between groups). Nebulisation was required by ten of 11 who had used a cup, nine of 11 who had used an unsealed bottle, eight of 11 who had used a sealed bottle, and only four of 11 who had used a conventional spacer. After nebulisation, improvement in FEV1 (15.5%) and PEF (26%) was more marked in children who had used a cup than in those who had used a conventional spacer (5.5% FEV1; 4% PEF), sealed bottle (3%; 0%), or unsealed bottle (7%; 9%). For 44 children with mild airways obstruction, response to bronchodilator was similar for all spacers and need for nebulisation was not associated with use of a particular spacer.

INTERPRETATION

A conventional spacer and sealed 500 mL plastic bottle produced similar bronchodilation, an unsealed bottle gave intermediate improvement in lung function, and a polystyrene cup was least effective as a spacer for children with moderate to severe airways obstruction. Use of bottle spacers should be incorporated into guidelines for asthma management in developing countries.

The critical region of overlap defining the AZFa male infertility interval of proximal Yq contains three transcribed sequences

The position of deletion breakpoints in a series of four AZFa male infertility patients has been refined using new markers derived from BAC clone DNA sequence covering the AZFa male infertility interval. The proximal half of the AZFa interval is occupied by pseudogene sequences with homology to Xp22. The distal half contains an anonymous expressed sequence tag (named AZFaT1) found transcribed in brain, testis, and skeletal muscle and the DFFRY and DBY genes. All the patients have AZFaT1 and DFFRY deleted in their entirety and three patients additionally have DBY deleted. The three patients with AZFaT1, DFFRY, and DBY deleted show a severe Sertoli cell only syndrome type I phenotype, whereas the patient that has retained DBY shows a milder oligozoospermic phenotype. The expression of DBY in a cell line from this latter patient is unaltered; this shows that it is the loss of genes lying within the deletion that is responsible for the observed oligozoospermia. RT-PCR analysis of mouse testis RNA from normal and XXSxr(a) mice (devoid of germ cells) has shown that Dby is expressed primarily in somatic cells and that the level of expression is unaltered during germ cell differentiation. This contrasts with Dffry where no transcripts are detectable in XXSxr(a) mouse testis and expression occurs specifically in testis mRNA in a germ cell dependent fashion.

A visit to the Republic of South Africa and Botswana: a modern country with a relic from the past

In a global health and communication focused society, it is evident that there is a growing need for health care professionals, especially nurses, to face challenges beyond traditional nursing care. Cultural awareness and values affect all areas of a person's life, including their beliefs about health and illness. The recent trip to South Africa and Botswana, a land that seemed so far away, was just only 18 short airline hours within reach. The Association of Black Nursing Faculty, Inc., Chi Eta Phi Sorority, Inc., and the Department of Nursing Education (University of Botswana) sponsored the trip to engage in professional dialogue of health concerns of many disadvantaged populations around the world for the 21st century. Although, this dialogue was an assurance that nurses around the globe do face challenges beyond a traditional nursing practice, it was also an assurance that there was a receptiveness toward teaching and the willingness to engage in health promotion behavior within a dominant culture that influences the lives of many people. In a land of sunshine and scenic majesty, were some of the world's strangest and most dramatic landscapes, nature's richest treasure chest of gold and diamonds with a unique wealth of animal and plant life. This land is also the home of big game, a host of birds, and has a legacy that is one of the most scenically dramatic, healthiest and challenging regions of the world.

Underascertainment of child abuse mortality in the United States

CONTEXT

Mortality figures in the United States are believed to underestimate the incidence of fatal child abuse.

OBJECTIVES

To describe the true incidence of fatal child abuse, determine the proportion of child abuse deaths missed by the vital records system, and provide estimates of the extent of abuse homicides in young children.

DESIGN AND SETTING

Retrospective descriptive study of child abuse homicides that occurred over a 10-year period in North Carolina from 1985-1994.

CASES

The Medical Examiner Information System was searched for all cases of children younger than 11 years classified with International Classification of Diseases, Ninth Revision codes E960 to E969 as the underlying cause of death and homicide as the manner of death. A total of 273 cases were identified in the search and 259 cases were reviewed after exclusion of fetal deaths and deaths of children who were not residents of North Carolina.

MAIN OUTCOME MEASURE

Child abuse homicide.

RESULTS

Of the 259 homicides, 220 (84.9%) were due to child abuse, 22 (8.5%) were not related to abuse, and the status of 17 (6.6%) could not be determined. The rate of child abuse homicide increased from 1.5 per 100000 person-years in 1985 to 2.8 in 1994. Of all 259 child homicides, the state vital records system underrecorded the coding of those due to battering or abuse by 58.7%. Black children were killed at 3 times the rate of white children (4.3 per 100000 vs 1.3 per 100000). Males made up 65.5% (133/203) of the known probable assailants. Biological parents accounted for 63% of the perpetrators of fatal child abuse. From 1985 through 1996, 9467 homicides among US children younger than 11 years were estimated to be due to abuse rather than the 2973 reported. The ICD-9 cause of death coding underascertained abuse homicides by an estimated 61.6%.

CONCLUSIONS

Using medical examiner data, we found that significant underascertainment of child abuse homicides in vital records systems persists despite greater societal attention to abuse fatalities. Improved recording of such incidences should be a priority so that prevention strategies can be appropriately targeted and outcomes monitored, especially in light of the increasing rates.

The validity and reliability of an OSCE in dentistry

The validity and reliability of a newly-developed objective structured clinical examination for 4th year dental students (OSCE(D)) were estimated by a range of quantitative and qualitative methods. The OSCE(D) consisted of 17 stations in conservation, periodontology and prosthetics. A blueprint was used to match the OSCE stations to clinical subject areas and to 7 skill clusters of clinical competence. Repeat measures of skills were undertaken in the OSCE(D) to maximise its validity and reliability. The primary purposes of the OSCE(D) were to assess clinical competence and to provide feedback to students. The results indicate that the OSCE(D) was intrinsically valid and a better predictor of performance in the final examination than either a concurrent 4th-year examination or Advanced-level university entry grades. The OSCE(D) scored relatively highly on internal consistency (Cronbach's alpha = 0.68). Intra-domain and inter-domain correlations were high and inter-examiner reliability was relatively high (eta 2 coefficients ranged from 0.00 to 0.10). There were no significant differences between performances in the morning and afternoon sessions of the examination so reproducibility is assumed to be high. Some improvement in individual stations and in inter-examiner reliability are required. A set of recommendations based on the experience of designing and testing a dental OSCE are provided.

Upgrading clinical decision support with published evidence: what can make the biggest difference?

BACKGROUND

To enhance clinical decision support, presented messages are increasingly supplemented with information from the medical literature. The goal of this study was to identify types of evidence that can lead to the biggest difference.

METHODS

Seven versions of a questionnaire were mailed to randomly selected active family practice physicians and internists across the United States. They were asked about the perceived values of evidence from randomized controlled trials, locally developed recommendations, no evidence, cost-effectiveness studies, expert opinion, epidemiologic studies, and clinical studies. Analysis of variance and pairwise comparisons were used for statistical testing.

RESULTS

Seventy-six (52%) physicians responded. On a Likert scale from one to six, randomized controlled clinical trial was the highest rated evidence (mean 5.07, SD +/- 1.14). Such evidence was significantly superior to locally developed recommendations and no evidence at all (P < .05). The interaction was also strong between the types of evidence and clinical areas (P = .0001).

CONCLUSION

While most health care organizations present data without interpretation or simply try to enforce locally developed recommendations, such approaches appear to be inferior to techniques of reporting data with pertinent controlled evidence from the literature. Investigating physicians' perceptions is likely to benefit the design of computer generated messages.

L-selectin interactions with novel mono- and multisulfated Lewisx sequences in comparison with the potent ligand 3'-sulfated Lewisa

The cell adhesion molecule L-selectin binds to 3'-sialyl-Lewis (Le)x and -Lea and to 3'-sulfo-Lex and -Lea sequences. The binding to 3'-sialyl-Lex is strongly affected by the presence of 6-O-sulfate as found on oligosaccharides of the counter receptor, GlyCAM-1; 6-O-sulfate on the N-acetylglucosamine (6-sulfation) enhances, whereas 6-O-sulfate on the galactose (6'-sulfation) virtually abolishes binding. To extend knowledge on the specificity of L-selectin, we have investigated interactions with novel sulfo-oligosaccharides based on the Lex pentasaccharide sequence. We observe that, also with 3'-sulfo-Lex, the 6-sulfation enhances and 6'-sulfation suppresses L-selectin binding. The 6'-sulfation without 3'-sialyl or 3'-sulfate gives no binding signal with L-selectin. Where the 6-sulfo,3'-sialyl-Lex is on an extended di-N-acetyllactosamine backbone, additional 6-O-sulfates on the inner galactose and inner N-acetylglucosamine do not influence the binding. Although binding to the 6,3'-sulfo-Lex and 6-sulfo, 3'-sialyl-Lex sequences is comparable, the former is a more effective inhibitor of L-selectin binding. This difference is most apparent when L-selectin is in paucivalent form (predominantly di- and tetramer) rather than multivalent. Indeed, as inhibitors of the paucivalent L-selectin, the 3'-sulfo-Lex series are more potent than the corresponding 3'-sialyl-Lex series. Thus, for synthetic strategies to design therapeutic oligosaccharide analogs as antagonists of L-selectin binding, those based on the simpler 3'-sulfo-Lex (and also the 3'-sulfo-Lea) would seem most appropriate.

Bistratene A induces a microtubule-dependent block in cytokinesis and altered stathmin expression in HL60 cells

Bistratene A is a cyclic polyether which affects cell cycle progression and can induce phosphorylation of cellular proteins. Treatment of HL60 cells with 100 ng/ml bistratene A was found to inhibit cytokinesis but had no effect on DNA synthesis and nuclear division. Consequently, bistratene A-treated cells became polyploid and multinucleate. In association with the development of this phenotype, the cytoplasmic protein stathmin was biphasically phosphorylated and levels of expression were doubled. Immunostaining of binucleate cells (bistratene A for 24 h) revealed increased alpha-tubulin localization where the cleavage furrow might be expected to form, i.e., along the equatorial plane. Treatment of these binucleate cells with the microtubule depolymerizing agent nocadazole promoted cleavage furrow formation and partially ameliorated the bistratene A-induced block in cell division. These findings implicate the polymerization status of microtubules and stathmin function in the regulation of cytokinesis.

Think before you speak: pauses, memory search, and trace redintegration processes in verbal memory span

Immediate memory span and speed of memory search were assessed for words and nonwords of short and long spoken duration. Memory span was substantially greater for words than for nonwords and for short than for long items, though speed of memory search was unaffected by either length or lexicality. An analysis of the temporal pattern of responses in the memory span task indicated that inter-item pauses were longer between nonwords than words but that these pause durations were unaffected by item length. A model of verbal short-term memory span is described in which trace selection from a short-term store and the redintegration (restoration) of degraded phonological traces both occur in the pauses between saying successive items. Both trace selection and trace redintegration appear to play important roles in accounting for individual differences in memory span.

Bacillus anthracis: medical issues of biologic warfare

Recent world events refocused attention on the possibility of nations engaging in biologic warfare, including an attack with Bacillus anthracis. The single available anthrax vaccine in the United States for human use, formerly known as MDPH-PA, has decreased ability to protect laboratory animals against virulent B. anthracis strains, especially compared with new vaccines being developed. Studies with these vaccines, however, have several shortcomings. The pathogenesis, diagnosis, treatment, and prophylaxis of anthrax are discussed, as well as the implications that an attack with B. anthracis would place on the health care system.

An assessment of a sedative algorithm for sleep in an intensive care unit

The difficulty for intensive care unit (ICU) patients to obtain frequent and extensive sleep has been well-documented. This project assessed the benefit of an algorithm of pharmacological assistance (lorazepam and methotrimeprazine) on sedation level and sleep duration in the ICU. The setting was a 15-bed closed ICU dealing with medical and surgical patients in a tertiary care, teaching hospital. Desired and actual levels of sedation for individual patients were determined hourly by the bedside nurse. Medications could be administered to facilitate achieving the desired level of sedation. Our results should no difference occurred in the achievement of the target sedation or duration of sleep with the implementation of the sedation algorithm. The amount of additional medication required during the night did change with the implementation of the sedation algorithm. A reduction in the amount of diazepam, morphine, and additional methotrimeprazine was noted. Efforts to change nursing practice will be required to improve the quality and quantity of sleep in ICU patients. This clinical evaluation demonstrates that the implementation of an algorithm for medication use is not effective alone in obtaining the desired level and duration of sleep in ICU patients. Nursing practice should continue to look at non-pharmacological factors, such as environmental noise, patient interruptions, and patient care practice to determine strategies in addition to medications which would aid the critically ill patient in achieving adequate sleep.

Clofibric acid: a potential therapeutic agent in AML and MDS

Differentiation therapy using retinoic acids (RAs) or 1alpha25-dihydroxyvitamin D3 (D3) is an attractive alternative to chemotherapy in acute myeloid leukaemia (AML) and myelodysplastic syndromes (MDS). However, with the exception of RA therapy for acute promyelocytic leukaemia (APL), RAs and D3 are not potent enough at doses that can be tolerated by patients. We demonstrate that clofibric acid (CA) enhances the response of HL60 cells to all-trans RA and D3. Our findings and those of others in the field lead us to suggest that combination therapy using all-trans RA and CA should be considered as potential therapy for AML and MDS.

Tumor, normal tissue, and plasma pharmacokinetic studies of fluorouracil biomodulation with N-phosphonacetyl-L-aspartate, folinic acid, and interferon alfa

PURPOSE

To evaluate the effect of N-phosphonacetyl-L-aspartate (PALA), folinic acid (FA), and interferon alfa (IFN-alpha) biomodulation on plasma fluorouracil (5FU) pharmacokinetics and tumor and liver radioactivity uptake and retention after [18F]-fluorouracil (5-[18F]-FU) administration.

PATIENTS AND METHODS

Twenty-one paired pharmacokinetic studies were completed on patients with colorectal, gastric, and hepatocellular cancer, utilizing positron emission tomography (PET), which allowed the acquisition of tumor, normal tissue, and plasma pharmacokinetic data and tumor blood flow (TBF) measurements. The first PET study was completed when the patient was biomodulator-naive and was repeated on day 8 after the patient had been treated with either PALA, FA, or IFN-alpha in recognized schedules.

RESULTS

TBF was an important determinant of tumor radioactivity uptake (r = .90; P < .001) and retention (r = .96; P < .001), for which radioactivity represents a composite signal of 5-[18F]-FU and [18F]-labeled metabolites and catabolites. After treatment with PALA, TBF decreased (four of four patients; P = .043), as did tumor radioactivity exposure (five of five patients; P = .0437), with no change in plasma 5FU clearance. With FA treatment, there were no differences observed in whole-body metabolism, plasma 5FU clearance, or tumor and liver pharmacokinetics. IFN-alpha had measurable effects on TBF and 5-[18F]-FU metabolism but had no apparent affect on liver blood flow.

CONCLUSION

The administration of PALA and IFN-alpha produced measurable changes in plasma, tumor, and liver pharmacokinetics after 5-[18F]-FU administration. No changes were observed after FA administration. In vivo effects may negate the anticipated therapeutic advantage of 5FU biomodulation with some agents.