Comparative productive performance of cows born through embryo transfer, artificial insemination and natural mating in dairy and dual-purpose herds raised in tropical conditions.

A populational, observational and longitudinal-retrospective study with records of 28 dairy-specialized and dual-purpose farms was carried out to compare the productive performance of cows born by embryo transfer (ET), artificial insemination (AI) and natural mating (NM), using the database of Centro Regional de Investigación para la Producción Animal Sostenible (CRIPAS) of cattle herds in Costa Rica. Herds (system × altitude), conception method (ET, AI and NM), genetic background (DSpB: specialized dairy breeds [Bos taurus] and crosses, GYR × HOL: Gyr × Holstein Crossbred and DSpB × BI: crosses between dairy breeds and Bos indicus), year of birth (or at calving), lactation number and days in milk were evaluated for the productive parameters age at first calving (AFC), calving to conception interval (CCI) and lactation milk yield (LMY) using a GLIMMIX procedure on SAS. The AFC, CCI and LMY were affected (p < .0001) by all factors considered in each parameter. ET has lower (p < .0001) AFC in months (33.1) than AI (35.2) and NM (36.44). NM had lower (p = .004) CCI (110 days) than AI or ET (121 days) values which were similar (p > .05). The higher LMY (p < .0001) was observed in ET (4140 kg), compared to AI (3706 kg) and NM (3595 kg). There was no difference between AI and NM. In conclusion, the method of conception in calves affected their future reproduction and production during puberty, postpartum and lactation. The effects on management decisions will require a rigorous economical study to discern whether ET would be a cost-effective alternative to AI or NM.

Hybrid Methacrylated Gelatin and Hyaluronic Acid Hydrogel Scaffolds. Preparation and Systematic Characterization for Prospective Tissue Engineering Applications.

Hyaluronic acid (HA) and gelatin (Gel) are major components of the extracellular matrix of different tissues, and thus are largely appealing for the construction of hybrid hydrogels to combine the favorable characteristics of each biopolymer, such as the gel adhesiveness of Gel and the better mechanical strength of HA, respectively. However, despite previous studies conducted so far, the relationship between composition and scaffold structure and physico-chemical properties has not been completely and systematically established. In this work, pure and hybrid hydrogels of methacroyl-modified HA (HAMA) and Gel (GelMA) were prepared by UV photopolymerization and an extensive characterization was done to elucidate such correlations. Methacrylation degrees of ca. 40% and 11% for GelMA and HAMA, respectively, were obtained, which allows to improve the hydrogels' mechanical properties. Hybrid GelMA/HAMA hydrogels were stiffer, with elastic modulus up to ca. 30 kPa, and porous (up to 91%) compared with pure GelMA ones at similar GelMA concentrations thanks to the interaction between HAMA and GelMA chains in the polymeric matrix. The progressive presence of HAMA gave rise to scaffolds with more disorganized, stiffer, and less porous structures owing to the net increase of mass in the hydrogel compositions. HAMA also made hybrid hydrogels more swellable and resistant to collagenase biodegradation. Hence, the suitable choice of polymeric composition allows to regulate the hydrogels´ physical properties to look for the most optimal characteristics required for the intended tissue engineering application.

Diffractive optical devices produced by light-assisted trapping of nanoparticles.

One- and two-dimensional diffractive optical devices have been fabricated by light-assisted trapping and patterning of nanoparticles. The method is based on the dielectrophoretic forces appearing in the vicinity of a photovoltaic crystal, such as Fe:LiNbO3, during or after illumination. By illumination with the appropriate light distribution, the nanoparticles are organized along patterns designed at will. One- and two-dimensional diffractive components have been achieved on X- and Z-cut Fe:LiNbO3 crystals, with their polar axes parallel and perpendicular to the crystal surface, respectively. Diffraction gratings with periods down to around a few micrometers have been produced using metal (Al, Ag) nanoparticles with radii in the range of 70-100 nm. Moreover, several 2D devices, such as Fresnel zone plates, have been also produced showing the potential of the method. The diffractive particle patterns remain stable when light is removed. A method to transfer the diffractive patterns to other nonphotovoltaic substrates, such as silica glass, has been also reported.

Differentiation and evolutionary relationships in Erythrinus erythrinus (Characiformes, Erythrinidae): occurrence and distribution of B chromosomes.

Erythrinus erythrinus, a Neotropical fish species of the Erythrinidae family, has a wide distribution in South America. Previous cytogenetic analysis showed that this species presents extensive karyotype diversity, with 4 karyomorphs (A-D) described herein. This study investigated the karyotypic structure of 2 new populations of E. erythrinus from the Brazilian Pantanal region, in order to improve the knowledge of the chromosomal diversity in this species. Both populations showed typical characteristics of karyomorph A, with 2n=54 chromosomes (6m+2st+46a), without differentiation between males and females. In addition, identical supernumerary B chromosomes, appearing as double-minute chromosomes, were also found in both populations. These findings suggest the presence of mitotic instability in view of their high intra- and inter-individual numerical variation. The presence of these chromosomes is likely a basal characteristic for this group, since the same kind of Bs also occurs in some other populations and karyomorphs of E. erythrinus. As such, they are important markers of biodiversity found in this nominal species, which probably corresponds to a species complex.

Immune-mediated hepatitis: Basic concepts and treatment.

Immunotherapy with immune checkpoint inhibitors (ICIs) has revolutionized advanced cancer management. Nevertheless, the generalized use of these medications has led to an increase in the incidence of adverse immune-mediated events and the liver is one of the most frequently affected organs. Liver involvement associated with the administration of immunotherapy is known as immune-mediated hepatitis (IMH), whose incidence and clinical characteristics have been described by different authors. It often presents as mild elevations of amino transferase levels, seen in routine blood tests, that spontaneously return to normal, but it can also manifest as severe transaminitis, possibly leading to the permanent discontinuation of treatment. The aim of the following review was to describe the most up-to-date concepts regarding the epidemiology, diagnosis, risk factors, and progression of IMH, as well as its incidence in different types of common cancers, including hepatocellular carcinoma. Treatment recommendations according to the most current guidelines are also provided.

Chromosomal diversity in Hypostomus (Siluriformes, Loricariidae) with emphasis on physical mapping of 18S and 5S rDNA sites.

We examined chromosomes of three species of the genus Hypostomus, in order to contribute to the understanding of the karyotype evolution of this group. Specimens of H. ancistroides and H. nigromaculatus displayed differences in karyotype formulas, distribution and location of heterochromatin and nucleolus organizer regions when compared to other populations of the same species. We made the first cytogenetic characterization of H. tapijara, an endemic species in the Ribeira de Iguape River. These specimens had 2n = 66 chromosomes, while H. ancistroides showed 2n = 68 and H. nigromaculatus 2n = 76 chromosomes. Physical mapping of 18S and 5S rDNA sites of the three species showed simple, multiple and syntenic clusters. Synteny of ribosomal sites was found in H. ancistroides and H. tapijara, and an interspersed pattern between these sites in all chromosomes bearing the synteny was observed. We conclude that the genus Hypostomus has a high chromosome complexity that is accompanied by great morphological variation. It is evident that this group comprises an interesting model for understanding the chromosome evolution of Neotropical ichthyofauna.

Pluronic F127 and P104 Polymeric Micelles as Efficient Nanocarriers for Loading and Release of Single and Dual Antineoplastic Drugs.

The potential application of biodegradable and biocompatible polymeric micelles formed by Pluronic F127 and P104 as nanocarriers of the antineoplastic drugs docetaxel (DOCE) and doxorubicin (DOXO) is presented in this work. The release profile was carried out under sink conditions at 37 °C and analyzed using the Higuchi, Korsmeyer-Peppas, and Peppas-Sahlin diffusion models. The cell viability of HeLa cells was evaluated using the proliferation cell counting kit CCK-8 assay. The formed polymeric micelles solubilized significant amounts of DOCE and DOXO, and released them in a sustained manner for 48 h, with a release profile composed of an initial rapid release within the first 12 h followed by a much slower phase the end of the experiments. In addition, the release was faster under acidic conditions. The model that best fit the experimental data was the Korsmeyer-Peppas one and denoted a drug release dominated by Fickian diffusion. When HeLa cells were exposed for 48 h to DOXO and DOCE drugs loaded inside P104 and F127 micelles, they showed lower IC50 values than those reported by other researchers using polymeric nanoparticles, dendrimers or liposomes as alternative carriers, indicating that a lower drug concentration is needed to decrease cell viability by 50%.

Safety of continuous propofol sedation for endoscopic procedures in elderly patients.

OBJECTIVE: to evaluate safety of continuous propofol sedation in elderly patients who undergo endoscopic procedures and investigate risk factors to develop complications in the geriatric population. MATERIAL AND METHODS: patients who received endoscopist-directed propofol sedation were classified into two groups according to age. Group I: > 80 years; Group II: < 80 years. Propofol was administered by continuous intravenous infusion to achieve deep sedation. Arterial oxygen saturation, heart rate, blood pressure, and electrocardiographic records were monitored during the procedure. Therapy and complications secondary to sedation were recorded. RESULTS: one thousand two-hundred and ninety-five endoscopic procedures (gastroscopies, colonoscopies and endoscopic ultrasonographies) were included. The dose of propofol was lower and therapy was more frequently performed in Group I. There were no differences between sedation-related complications in both groups (Group I: 15.4%, Group II: 14%; p:n.s.). Patients in Group I showed greater tendency to develop severe oxygen desaturation in the colonoscopy and endoscopic ultrasonography procedures. In the univariate analysis, a higher dose of propofol was associated with the appearance of complications (157.4 ± 84.4 vs 121.3 ± 89.6 mg) in elderly patients but it was not associated with severe oxygen desaturation. CONCLUSIONS: continuous propofol sedation during endoscopic procedures in elderly patients > 80 years is as safe as in younger patients.

Analysis of the peri-implant microbiota in 90 dental implants and its relationship to crevicular fluid volume.

OBJECTIVE: To evaluate the presence within the peri-implant sulcus of Tannerela forsythia (Tf), Porphyromonas gingivales (Pg), Treponema denticola (Td) and Aggregatibacter actinomycetemcomitans (Aa), and relate these bacteria to the peri-implant crevicular fluid volume (PICFV). MATERIAL AND METHOD: A prospective and cross-sectional clinical case series study was made. For the measurement of crevicular fluid, use was made of the Periotron® 8000 (Proflow Incorporated. New York, USA), measuring the volume in Periotron units (PU). For the detection of periodontopathogenic bacteria we used the IAI-PadoTest 4.5 (IAI Inc., IAI Institute, Zuchwil, Switzerland) - a system for the detection of Tf, Pg, Td and Aa based on the use of RNA arrays. RESULTS: We included 34 patients (19 females and 15 males) with a mean age of 56.4 years. Of these subjects, 30.8% were smokers and 69.2% non-smokers. Out of a total series of 213 implants, we analyzed the crevicular fluid and microbiota in 90 implants. A total of 16.5% of the implants presented mucositis, while 83.5% were in healthy peri-implant conditions. The microbiological study revealed the presence of Tf in 17.1% of the implants, Pg in 9.3%, Td in 13.6%, in Aa in none of the implants. The mean Periotron reading was 93.4 PU (range 12-198 PU). A statistically significant (p<0.05) relationship was observed between PICFV and the total percentage bacteria (Tf, Pg and Td) - with a strong association between the Td levels and smoking (p<0.01). In the implants with mucositis, the concentration of Pg and Td was greater. CONCLUSIONS: In the implants studied, the subgingival peri-implant microbiota was characterized by low levels of Pg, Tf, Td, and none of the patients proved positive for Aa. These bacteria showed a positive correlation to crevicular fluid volume, and a statistically significant relationship was observed between Td and smoking.

Short- and long-term effects of temporary early cow-calf separation or restricted suckling on well-being and performance in zebu cattle.

Information on weaning techniques in the tropics is scarce, particularly regarding the long-term effect of temporary early cow-calf separation or restricted suckling. Therefore, we studied the effects of these two handling practices on well-being and performance at 150 days postpartum in fifteen zebu cow-calf pairs randomly assigned to three treatments. Continuous suckling (CS) where calves remained with their dams from birth to weaning; restricted suckling (RS) calves were allowed to suckle 30 min/day from Day 34 until weaning at Day 150 and kept separated the rest of the time; temporary separation (TS) calves were separated for 72 h from their dams from Day 33 to 36 but remained with their dams the rest of the time. Blood samples and behavioral data were collected on Days 32-36 (1st period) and 149-153 (2nd period). In the 1st period, a greater percentage of RS and TS calves were observed close to the fence line (<10 m) that separated them from their dams (P < 0.0001) and vocalized more than CS calves (P < 0.0001), while in the 2nd period, RS calves had the highest cortisol concentration and vocalization rate (P < 0.05). Similarly, during the 1st period, a greater percentage of RS and TS cows were observed close to the fence line than CS cows (P < 0.0001), with TS cows vocalizing the most (P = 0.001). In the 2nd period, RS cows had greater cortisol concentration than TS (P = 0.037) and CS cows (P = 0.003). More TS and CS cows than RS were observed close to the fence line (P = 0.03 and P = 0.05). On Day 150, TS calves and cows vocalized more than RS and CS animals (P < 0.0001). Before calf-cow separation, 27 out of 45 cows were cycling (CS = 10; RS = 6; TS = 11). After separation, 12 of the remaining 18 cows resumed ovarian activity (CS = 3; RS = 5; TS = 4), and all cows were cycling after estrous synchronization treatment. The pregnancy rate was similar between CS, RS, and TS (60, 53, and 60% respectively). In conclusion, temporary separation increased calf distress response to definitive weaning even four months later, while restricted suckling seemed to reduce it.

Peficitinib hydrobromide to treat rheumatoid arthritis.

Peficitinib hydrobromide is a small Janus kinase inhibitor (JAK1, JAK2, JAK3 and TYK2) molecule for the treatment of rheumatoid arthritis (RA). Phase II and phase III clinical trials and extension studies with different doses have been conducted to assess the drug's efficacy and safety with substantially improved outcomes observed in RA. This JAK inhibitor oral drug demonstrated clinical response as once-daily monotherapy in patients with moderate to severe RA, also in combination with methotrexate (MTX), who had an inadequate response to MTX. The findings from studies of this new JAK inhibitor have shown that, both in monotherapy as well as in combination with conventional synthetic disease-modifying antirheumatic drugs (csDMARDs), it has efficacy, safety and tolerability in RA patients.

Spraying ozonated water on Bobal grapevines: Effect on grape quality.

Ozone is a powerful oxidant that is increasingly used as sanitizing agent in the wine industry and even in the vineyard to control grapevine diseases. In this study, we evaluated the effect on grape enological quality of ozonated water spraying treatments carried out in Bobal grapevines during two consecutive harvest seasons. In the first season, ozonated water was applied once during the ripening period on grapevines trained on the traditional gobelet system (S1). In the second season, ozonated water was applied three times between the fruit set and harvest on grapevines grown on a vertical trellis system (S2). Grape quality on harvest day was evaluated through several enological and chromatic parameters, the phenolic maturity, the Varietal Aroma Potential Index (IPAv) and the phenolic and volatile composition. The S1 treatment had a positive effect on the technological maturity, the chromatic parameters, the seed maturity and the content of glycosylated aroma precursors, phenolic compounds and free terpenoids of grapes. The S2 treatment also improved the technological maturity and the content of total anthocyanins (pH 1.0) and free terpenoids, but had a negative impact on the chromatic parameters, the anthocyanin extractability and the content of glycosylated aroma precursors and phenolic compounds. Therefore, ozonated water sprayed on Bobal grapevines affected the quality of grapes, but the effect seemed to depend on the number of applications.

[Cryosurgery in the management of prostate cancer]. / Criocirugía en el tratamiento del cáncer de próstata.

This article reviews the current status of the prostatic cryosurgery in the management of patients with prostate cancer. Recent advances in cryoablative technology have allowed to treat these patients successfully with decreased morbidity. Using transrectal high-resolution ultrasound imaging, prostate cryotherapy is delivered with multiple ultrathin (17-gauge) cryo-needles, via percutaneous transperineal approach. The extent of freezing can be precisely controlled and monitored with thermic devices, tissue destruction is monitored with real-time visualization of the prostate and surrounding structures, and urethral warming is used to avoid urethral sloughing. However, the results with the second and third-generation cryosurgical equipment will have to be confirmed by means of prospective and randomized trials, because up to now we only have data based on retrospective analyses, which are very heterogeneous. The ability of prostate-specific antigen (PSA) to predict long-term outcome after cryotherapy for localized prostate cancer is not well known because experience with this treatment modality is still limited; however, it seems that a PSA value of 0.5 ng/ml or less after 6 months or longer after cryotherapy would be associated with a high probability (greater than 95%) of negative post-treatment biopsy. Cryosurgery could also be an option of treatment for men with recurrent local disease who have undergone radiotherapy or radical prostatectomy. We have to keep in mind possible complications (incontinence, impotency, urethrorectal fistula or bladder outlet obstruction. The favorable side effect profile and preliminary oncologic and funtional results could suggest that cryosurgery will have a role in the minimally invasive management of selected patients with prostate cancer.

Ventricular Fibrillation and Tachycardia detection from surface ECG using time-frequency representation images as input dataset for machine learning.

BACKGROUND AND OBJECTIVE: To safely select the proper therapy for Ventricullar Fibrillation (VF) is essential to distinct it correctly from Ventricular Tachycardia (VT) and other rhythms. Provided that the required therapy would not be the same, an erroneous detection might lead to serious injuries to the patient or even cause Ventricular Fibrillation (VF). The main novelty of this paper is the use of time-frequency (t-f) representation images as the direct input to the classifier. We hypothesize that this method allow to improve classification results as it allows to eliminate the typical feature selection and extraction stage, and its corresponding loss of information. METHODS: The standard AHA and MIT-BIH databases were used for evaluation and comparison with other authors. Previous to t-f Pseudo Wigner-Ville (PWV) calculation, only a basic preprocessing for denoising and signal alignment is necessary. In order to check the validity of the method independently of the classifier, four different classifiers are used: Logistic Regression with L2 Regularization (L2 RLR), Adaptive Neural Network Classifier (ANNC), Support Vector Machine (SSVM), and Bagging classifier (BAGG). RESULTS: The main classification results for VF detection (including flutter episodes) are 95.56% sensitivity and 98.8% specificity, 88.80% sensitivity and 99.5% specificity for ventricular tachycardia (VT), 98.98% sensitivity and 97.7% specificity for normal sinus, and 96.87% sensitivity and 99.55% specificity for other rhythms. CONCLUSION: Results shows that using t-f data representations to feed classifiers provide superior performance values than the feature selection strategies used in previous works. It opens the door to be used in any other detection applications.

Compatibility of medications with 3-in-1 parenteral nutrition admixtures.

BACKGROUND: The absence of drug compatibility information with 3-in-1 parenteral nutrition admixtures has been problematic. The purpose of this project was to evaluate the physical compatibility of 106 selected drugs during simulated Y-site injection into nine different 3-in-1 parenteral nutrition admixture formulations. METHODS: Four-milliliter samples of each of the representative 3-in-1 parenteral nutrition admixture formulations were combined in a 1:1 ratio with 4-mL samples of each of 106 drugs, including supportive care drugs, anti-infectives, and antineoplastic drugs. Six replicate samples of each combination were prepared. Two samples were evaluated initially after mixing, two more after 1 hour, and the last two after 4 hours at 23 degrees C. At each test interval, the samples were subjected to centrifugation, causing the fat to rise to the top. The top fat layer and most of the aqueous phase were removed, and the remaining liquid was diluted with about 7 mL of particle-free, high-performance liquid chromatography-grade water to facilitate observation of any particulates that might have formed. Visual examinations were performed in normal diffuse fluorescent laboratory light and under high-intensity, monodirectional light. RESULTS: Most of the drugs tested were physically compatible with the 3-in-1 parenteral nutrition admixtures for 4 hours at 23 degrees C. However, 23 drugs exhibited various incompatibilities with one or more of the parenteral nutrition admixtures. Six drugs resulted in the formation of precipitate with some or all of the admixtures. Seventeen drugs caused disruption of the emulsion, usually with oiling out. CONCLUSIONS: Most of the test drugs were physically compatible with the nine representative 3-in-1 parenteral nutrition admixtures. However, the 23 drugs that resulted in incompatibilities should not be administered simultaneously with the incompatible parenteral nutrition admixtures via a Y injection site.

Application of adaptive signal processing for determining the limits of P and T waves in an ECG.

A new algorithm for the determination of the limits of P and T waves is proposed, and its foundations are mathematically analyzed. The algorithm performs an adaptive filtering so that the searched point corresponds to a minimum. Crucial properties of its performance are discussed, i.e., immunity to base line drifts and full adaptation to any cardiological criteria. A series of tests are made involving real registers with different morphologies for P and T-waves.

Compatibility of amifostine with selected drugs during simulated Y-site administration.

The compatibility of amifostine for injection with selected other drugs during simulated Y-site injection was evaluated. Five-milliliter samples of amifostine 10 mg/mL in 5% dextrose injection were combined with 5 mL each of 100 other drugs, including antineoplastics, anti-infectives, and supportive care drugs, in 5% dextrose injection or 0.9% sodium chloride injection. The combinations were stored under fluorescent light at 23 degrees C. The combinations were evaluated initially and at one and four hours after preparation. Visual examinations were performed in fluorescent light with the unaided eye and using a high-intensity monodirectional light beam to enhance visualization of small particles and low-level turbidity. The turbidity of each sample was measured. Particle sizing and counting were performed on selected samples. Most of the test drugs were compatible with amifostine 10 mg/mL for the observation period. However, 10 drugs exhibited various incompatibilities, including turbidity, particulate formation, precipitation, and color change. These drugs were acyclovir sodium, amphotericin B, cefoperazone sodium, chlorpromazine hydrochloride, cisplatin, ganciclovir sodium, hydroxyzine hydrochloride, miconazole, minocycline hydrochloride, and prochlorperazine edisylate. Amifostine 10 mg/mL in 5% dextrose injection was compatible with most of the 100 drugs tested for four hours at 23 degrees C. However, 10 drugs exhibited incompatibility with amifostine.

Compatibility of aztreonam with selected drugs during simulated Y-site administration.

The compatibility of aztreonam injection with selected other drugs during simulated Y-site injection was evaluated. A 5-mL sample of aztreonam 40 mg/mL in 5% dextrose injection was combined with 5 mL of each of 100 other drugs including antineoplastics, anti-infectives, and supportive care drugs in 5% dextrose injection or 0.9% sodium chloride injection. The combinations were stored under fluorescent light at 23 degrees C. The combinations were evaluated initially and at one and four hours after preparation by examination with the unaided eye and with a high-intensity light beam, turbidity measurement, and particle sizing and counting. Most of the test drugs were compatible with aztreonam 40 mg/mL for the observation period. However, aztreonam combinations with 12 drugs exhibited incompatibilities including turbidity, particulate formation, precipitation, and color change. These drugs were acyclovir sodium, amphotericin B, chlorpromazine hydrochloride, daunorubicin hydrochloride, ganciclovir sodium, lorazepam, metronidazole, miconazole, mitomycin, mitoxantrone hydrochloride, prochlorperazine edisylate, and streptozocin. Aztreonam 40 mg/mL in 5% dextrose injection was compatible with most of the drugs tested for up to four hours at 23 degrees C. However, 12 drugs exhibited incompatibility with aztreonam.

Compatibility of thiotepa (lyophilized) with selected drugs during simulated Y-site administration.

The compatibility of lyophilized thiotepa injection with selected other drugs during simulated Y-site injection was evaluated. Five-milliliter samples of thiotepa (lyophilized) 1 mg/mL in 5% dextrose injection were combined with 5 mL each of 100 other drugs, including antineoplastics, anti-infectives, and supportive care drugs, in 5% dextrose injection or 0.9% sodium chloride injection. The combinations were stored at room temperature (approximately 23 degrees C) under constant fluorescent light. Visual examinations were performed immediately and at one and four hours with the unaided eye and, if there was no obvious incompatibility, with a high-intensity mono-directional light beam to enhance visualization of small particles and low-level turbidity. The turbidity of each combination was measured as well. Particle sizing and counting were performed on selected solutions. Most of the test drugs were compatible with thiotepa 1 mg/mL during the observation period. Two drugs exhibited incompatibilities with thiotepa. The thiotepa-cisplatin combination developed turbidity in four hours, and the thiotepa-minocycline hydrochloride combination developed a bright yellow-green discoloration in one hour. All the test drugs except cisplatin and minocycline hydrochloride were compatible with thiotepa 1 mg/mL (prepared from the lyophilized formulation) for at least four hours at room temperature.

Incompatibility of fluorouracil with leucovorin calcium or levoleucovorin calcium.

The physical compatibility of fluorouracil mixed with leucovorin calcium or levoleucovorin calcium, undiluted and modestly diluted with 5% dextrose injection, was evaluated. Fluorouracil 50 mg/mL was combined in duplicate with leucovorin or levoleucovorin 20 mg/mL (as the calcium salt) in 250-mL polyvinyl chloride (PVC) portable-pump reservoirs in six volume ratios, either undiluted or diluted with 5% dextrose injection (to a final volume 25% greater than the drug volume). Duplicate reservoirs of each combination were stored for seven days at 4, 23, or 32 degrees C. Samples were evaluated visually with a high-intensity monodirectional light beam to observe development of particulates. Turbidimetry and light-obscuration particle counting and sizing also were used to evaluate compatibility. Small amounts of tiny crystalline particles developed in most of the combinations, usually by four days. In some cases, the particles could be seen in normal diffuse room light. Particle content was greater with higher leucovorin concentrations and over longer storage periods. Storage temperature did not play a consistent role in particle development. Fluorouracil and leucovorin calcium or levoleucovorin calcium were not compatible when stored in PVC reservoirs at 4, 23, or 32 degrees C.