Biomedical subjects

J Maas

Publications and source records attributed to J Maas.

At least 19 recordsLinked to original sources

PubMed2006

Imaging data suggesting acute pyelonephritis in the kidney graft: report of five cases with atypical clinical presentation.

Acute pyelonephritis is a common complication of kidney transplantation, occurring in up to 1% of grafts. Diagnosis is mainly clinical and atypical presentations have seldom been reported. The diagnostic role of imaging techniques has not been defined. Five cases of acute graft pyelonephritis are reported (three kidney, two pancreas-kidney grafts). The patients (median age 48 years) comprised three females and two males. Median post-transplant follow-up was 3 months, with three patients having predisposing factors for diabetes and one for an enteric bladder. None of the patients presented the 'classic' diagnostic tetrad (i.e. fever, positive urine cultures, low urinary tract symptoms and serum creatinine increase); although, at diagnosis, two of five patients presented with fever, one had increased creatinine levels and one had positive urine cultures. Of note, three patients had leucocyte casts at urinary sediment analysis, thus raising clinical suspicion. Renal ultrasounds were negative in all patients. Renal (99m)Tc-MAG3 (mercaptoacetyltriglycine) scintigraphy, which was used for the definition of kidney function impairment (one patient) or because of the presence of urinary casts (three patients), or after the biopsy diagnosis to locate the parenchymal lesions (one patient), was positive in all patients. The presence and pyelonephritic origin of the parenchymal lesions was confirmed by nuclear magnetic resonance or computed tomography scans. Acute graft pyelonephritis may develop in the absence of a full-blown clinical picture. Smouldering symptoms may occur in the presence of large perfusion deficits. (99m)Tc-MAG3 scintigraphy could be an important diagnostic tool in such cases.

Acute Disease↗

PubMed2001

Durable HIV-1 suppression with indinavir after failing lamivudine-containing double nucleoside therapy: a randomized controlled trial.

OBJECTIVE: To assess the durability of the antiretroviral effect in plasma and cerebrospinal fluid (CSF) of antiviral therapy intensification, produced by the addition of indinavir from week 12 onwards to the original regimen of zidovudine/lamivudine or stavudine/lamivudine, after 72 weeks of follow-up using an ultrasensitive HIV-1 RNA assay. To assess CSF concentrations of indinavir at week 48. DESIGN: In a prospectively, randomized, open, single-centre study, antiretroviral-naive patients (CD4 cell count > or =200 cells/microl and a plasma HIV-1 RNA level 10,000 copies/ml) were assigned to a combination of zidovudine/lamivudine or stavudine/lamivudine. Indinavir could be added to the double nucleoside analogue regimen from week 12 or thereafter in case the plasma HIV RNA level was insufficiently suppressed (>500 copies/ml). RESULTS: Forty-seven patients were enrolled (23 stavudine/lamivudine and 24 zidovudine/lamivudine), of whom 33 completed a follow-up of 72 weeks. Indinavir was added in 89% (42/47) of the patients. Only one discontinuation occurred due to virological failure. At week 72, the median plasma HIV-1 RNA levels in the zidovudine/lamivudine group had decreased from 4.80 log10 copies/ml to <500 copies/ml in 100% of patients and <50 copies/ml in 86.6% of the patients. In the stavudine/lamivudine group the plasma HIV-1 RNA decreased from 4.98 log10 copies/ml at baseline to <500 copies/ml in 100% of patients and <50 copies/ml in 66.7% of the patients. On an intent-to-treat basis these figures were 54.2 and 52.2% for zidovudine/lamivudine and stavudine/lamivudine, respectively, for the 50 copies/ml assay. The median CD4 cell count increased from 315 cells/microl, with 150 cells/microl in the zidovudine/lamivudine arm, and from 290 cells/microl, with 310 cells/microl in the stavudine/lamivudine arm (P=0.0001). However, the percentage of CD4 cells did not differ in each group. In the zidovudine/lamivudine group 9/10 and 5/5, and in the stavudine/lamivudine group 11/11 and 6/6 had a CSF HIV-1 RNA level <50 copies/ml at week 12 and 48, respectively. The CSF indinavir concentration ranged from 50 to 170 ng/ml. CONCLUSION: The long-term HIV-1 suppression observed in this study is remarkable, as adding a single antiretroviral agent to a failing regimen goes against current notions of adequate therapy.

Acquired Immunodeficiency Syndrome↗

PubMed2000

Quantitative whole-body autoradiography: recommendations for the standardization of the method.

The objective of this article is to identify the best conditions for preparing, handling, and exposing radioactive sections by using the Fujix BAS 2000 system for quantitative radioluminography. Regarding the influence of thickness of sections, thicker sections may allow shorter exposure times due to the increased radioactivity, but on the other hand they take more time for the freeze-drying process, resolution will be reduced, and the recovery of radioactivity will be lower due to increased self-absorption particularly in organs like bones or teeth. The pretreatment of the sections should depend on the method of exposure. Powdering with talcum is the most recommendable method when vacuum packaging the imaging plates and sections. Spraying with Nobecutan is recommended when using the cartridge method. Particularly for low concentrations, the vacuum-contact method should be the method of choice. To avoid a flare effect, the geometrical arrangement of the sections on the imaging plate (IP) should always be vertical to the scanning direction of the laser. An exposure time longer than 10 days is not recommended and the time between the end of exposure and start of scanning should be as short as possible. In order to reduce the background signal, it is necessary to expose the IPs in a shielding box in a cold environment. No positive chemographic effects of sections were found.

Animals↗

PubMed2000

Quantitative distribution studies in animals: cross-validation of radioluminography versus liquid-scintillation measurement.

The results of a cross-validation of the radioluminography (RLG) and liquid scintillation counting (LSC) methods are presented. The methods for the determination of radioactivity concentrations were compared in 16 organs, after administration of (14)C-labeled substances to rats. LSC measurements of two kinds were used as reference methods for RLG: (1) quantitative determination of radioactivity after conventional dissection (interindividual comparison) and (2) quantitative determination of radioactivity in tissue punches taken from the whole-body sections after they had undergone RLG measurement (intraindividual comparison). Blood standards containing known concentrations were used for calibration. For statistical evaluation log-linear regression analysis of paired concentration values and organ-specific 95% confidence intervals of the log-transformed RLG/LSC concentration quotients were compared. For most organs, the slopes of the regression lines and the means of the concentration quotients were within the defined equivalence range of 0.80-1.25. Deviations were distinctly smaller in the intraindividual comparison. For some organs, however, it became clear that found concentrations were affected by self-absorption (RLG) and by differences in sample preparation (LSC). In conclusion, quantification with RLG is a reliable and reproducible method with comparable measurement precision and greater accuracy in respect of tissue localization, compared to LSC (dissection).

Animals↗

PubMed2000

Papio cynocephalus endogenous retrovirus among old world monkeys: evidence for coevolution and ancient cross-species transmissions.

To study the evolutionary history of Papio cynocephalus endogenous retrovirus (PcEV), we analyzed the distribution and genetic characteristics of PcEV among 17 different species of primates. The viral pol-env and long terminal repeat and untranslated region (LTR-UTR) sequences could be recovered from all Old World species of the papionin tribe, which includes baboons, macaques, geladas, and mangabeys, but not from the New World monkeys and hominoids we tested. The Old World genera Cercopithecus and Miopithecus hosted either a PcEV variant with an incomplete genome or a virus with substantial mismatches in the LTR-UTR. A complete PcEV was found in the genome of Colobus guereza-but not in Colobus badius-with a copy number of 44 to 61 per diploid genome, comparable to that seen in papionins, and with a sequence most closely related to a virus of the papionin tribe. Analysis of evolutionary distances among PcEV sequences for synonymous and nonsynonymous sites indicated that purifying selection was operational during PcEV evolution. Phylogenetic analysis suggested that possibly two subtypes of PcEV entered the germ line of a common ancestor of the papionins and subsequently coevolved with their hosts. One strain of PcEV was apparently transmitted from a papionin ancestor to an ancestor of the central African lowland C. guereza.

Animals↗

PubMed1999

Proteasome inhibitors: a novel class of potent and effective antitumor agents.

The ubiquitin-proteasome pathway plays a critical role in the regulated degradation of proteins involved in cell cycle control and tumor growth. Dysregulating the degradation of such proteins should have profound effects on tumor growth and cause cells to undergo apoptosis. To test this hypothesis, we developed a novel series of proteasome inhibitors, exemplified by PS-341, which we describe here. As determined by the National Cancer Institute in vitro screen, PS-341 has substantial cytotoxicity against a broad range of human tumor cells, including prostate cancer cell lines. The PC-3 prostate cell line was, therefore, chosen to further examine the antitumor activity of PS-341. In vitro, PS-341 elicits proteasome inhibition, leading to an increase in the intracellular levels of specific proteins, including the cyclin-dependent kinase inhibitor, p21. Moreover, exposure of such cells to PS-341 caused them to accumulate in the G2-M phase of the cell cycle and subsequently undergo apoptosis, as indicated by nuclear condensation and poly(ADP-ribose) polymerase cleavage. Following weekly i.v. treatment of PS-341 to mice bearing the PC-3 tumor, a significant decrease (60%) in tumor burden was observed in vivo. Direct injection of PS-341 into the tumor also caused a substantial (70%) decrease in tumor volume with 40% of the drug-treated mice having no detectable tumors at the end of the study. Studies also revealed that i.v. administration of PS-341 resulted in a rapid and widespread distribution of PS-341, with highest levels identified in the liver and gastrointestinal tract and lowest levels in the skin and muscle. Modest levels were found in the prostate, whereas there was no apparent penetration of the central nervous system. An assay to follow the biological activity of the PS-341 was established and used to determine temporal drug activity as well as its ability to penetrate tissues. As such, PS-341 was shown to penetrate PC-3 tumors and inhibit intracellular proteasome activity 1.0 h after i.v. dosing. These data illustrate that PS-341 not only reaches its biological target but has a direct effect on its biochemical target, the proteasome. Importantly, the data show that inhibition of this target site by PS-341 results in reduced tumor growth in murine tumor models. Together, the results highlight that the proteasome is a novel biochemical target and that inhibitors such as PS-341 represent a unique class of antitumor agents. PS-341 is currently under clinical evaluation for advanced cancers.

Algorithms↗

PubMed1998

Presence of the variant mannose-binding lectin alleles associated with slower progression to AIDS. Amsterdam Cohort Study.

OBJECTIVE: To examine the association between mannose-binding lectin (MBL) polymorphism and progression to AIDS and death in HIV-1 infection. DESIGN AND METHODS: In 131 HIV-1-infected homosexual seroconverters, survival analyses were performed to determine both the association between MBL genotype and time from HIV-1 seroconversion to AIDS and death, and time from AIDS to death. RESULTS: Of the 131 seroconverters, of whom 61 developed AIDS, 76 were typed as homozygous wild-type and 55 as carriers of variant alleles (52 heterozygous and three homozygous variant alleles). A Survival analyses suggested that HIV-1-infected men with the variant alleles progressed somewhat slower to AIDS [relative hazard (RH), 0.62; 95% confidence interval (CI), 0.36-1.10] and death (RH, 0.73; 95% CI, 0.42-1.25). Interestingly, CD4+ T-cell count determined at the moment of AIDS was found to be significantly lower among persons with the mutation (97 x 10(6)/l versus 204 x 10(6)/l; P=0.03). Furthermore, when AIDS-free times before the diagnosis of an opportunistic infection were compared with those preceding a diagnosis of Kaposi's sarcoma, Kaposi's sarcoma diagnosis was more postponed than that of an opportunistic infection (RH, 0.21; 95% CI, 0.05-0.95; versus RH, 0.67; 95% CI, 0.35-1.27). CONCLUSION: Indications for a weak pre-AIDS protective effect of variant MBL alleles were demonstrated.

Acquired Immunodeficiency Syndrome↗

PubMed1998

An open randomized controlled trial of zidovudine plus lamivudine versus stavudine plus lamivudine.

OBJECTIVE: To compare the antiretroviral effect and safety of zidovudine (ZDV)-lamivudine (3TC) with that of stavudine (d4T)-3TC. METHODS: In an open randomized controlled trial antiretroviral therapy-naive patients who had CD4+ counts > or = 200 x 10(6)/l and plasma HIV RNA load > or = 10000 copies/ml were randomized to receive ZDV-3TC (200 mg three times daily and 150 mg twice daily, respectively) or d4T-3TC (40 mg and 150 mg, both twice daily). If the plasma HIV RNA level at week 8 or thereafter was > 500 copes/ml, indinavir was added at the next scheduled visit. Genotypic resistance analysis of the reverse transcriptase gene was performed at week 0 and 12. Results over 24 weeks were reported. RESULTS: Forty-seven patients were treated (24 took ZDV-3TC; 23 took d4T-3TC). Plasma HIV RNA levels decreased from median 4.80 to 3.15 log10 copies/ml (ZDV-3TC, P < 0.0001) and from 4.98 to 3.03 log10 copies/ml (d4T-3TC, P < 0.0001) after 12 weeks of treatment. Indinavir was added at week 12 in 11 out of 21 patients with ZDV-3TC and in 10 out of 22 patients with d4T-3TC. Median virus load at week 24 was 2.41 log10 and 2.29 log10 copies/ml (P=0.14), respectively. Seventy-five per cent (15 out of 20; ZDV-3TC) and 95% (18 out of 19; d4T-3TC) of patients had a virus load of < 500 copies/ml. Genomic evidence for 3TC resistance was found in all patients tested (11/11 ZDV-3TC and 12/12 d4T-3TC). At week 12, CD4 cell counts had increased with a median of 110 x 10(6)/l in the ZDV-3TC group (baseline, 315 x 10(6)/l) and a median of 115 x 10(6)/l in the d4T-3TC group (baseline 290 x 10(6)/l). At week 24, the median increases were 90 and 120 x 10(6)/l, respectively. Overall the increase of CD4+ cells was higher in the d4T-3TC group (P=0.02). CONCLUSION: d4T-3TC is at least as effective as ZDV-3TC, but 3TC resistance emerged in all patients investigated. The virological response of the dual nucleoside combination is of short duration. However, after addition of indinavir the virus load could be reduced to < 500 copies/ml in the majority of patients. The increase in CD4+ cell count was significantly greater in the d4T-3TC group. To prevent 3TC resistance, the drug should not be used in regimens containing only two nucleosides, irrespective the virus load at baseline.

Adult↗

PubMed1998

Morbidity and mortality of reconstructive surgery of noninfected false aneurysms detected long after aortic prosthetic reconstruction.

OBJECTIVE: To determine the morbidity and mortality of surgical treatment of false (anastomotic) aneurysms, we analyzed the results of 158 consecutive surgical procedures for repair of false aneurysms that were detected as a result of a surveillance program after aortic reconstruction with a prosthesis. DESIGN: Retrospective analysis of patient data from a vascular registry that included information on the long-term follow-up of our patients. SETTING: A university hospital (tertiary referral center) in the Netherlands that has been performing vascular reconstructive surgery since 1958. PATIENTS: We performed 158 surgical procedures on 135 patients with 220 noninfected false aneurysms. Using a yearly surveillance program, the false aneurysms were detected at a mean interval of 8 years after the initial reconstruction. Most patients (60%) were asymptomatic. The operation was performed as an emergency in 25 instances (16%). RESULTS: The mortality rate of patients receiving nonsurgical treatment was very high (61%) owing to documented rupture (11 of 18 patients). The intraoperative death rate was 7.6% per procedure. This was higher for emergency (24%) than for elective procedures (4.5%). CONCLUSIONS: Conservative follow-up carries a very high mortality rate, as does emergency surgery for a false aneurysm. However, the intraoperative mortality rate of elective reconstruction of a false aneurysm can be in the same range as that of elective primary aortic reconstruction. Therefore, we advocate a surveillance program, including yearly ultrasound studies, after prosthetic aortic reconstruction for the timely detection and elective repair of all false aneurysms.

Adult↗

PubMed1998

The use of an oligonucleotide that hybridizes to DNA sequences interspersed in the genome of members of the genus Phytophthora as an adjunct to morphological criteria in species identification.

An oligonucleotide (primer), designed from a conserved region of the multi-allelic b locus of the basidiomycete fungus Ustilago maydis, generated reproducible PCR fingerprints in Phytophthora species. The primer hybridized in a species-specific manner to nucleotide sequences interspersed in the genome of the closely related members of Phytophthora taxonomic group IV. We recommend the use of this PCR procedure as an alternative method for resolving the close taxonomic affinity of some members of the genus Phytophthora.

DNA↗

PubMed1998

Water vapor sorption studies on the physical stability of a series of spray-dried protein/sugar powders for inhalation.

One theory suggests that by maintaining the protein in an amorphous glassy sugar matrix, the physical hindrance encountered by the protein functions to stabilize it. Thus, the nature of the sugar/protein interaction is important as is the maintenance of the sugar in an amorphous form without any recrystallization. Moisture is known to function as a plasticizer and facilitate crystallization and thus loss of the amorphous state. We report the effect of cospray-drying with different proteins on the physical stability of lactose and mannitol. Particle sizing showed their suitability for inhalation, and the effect of exposure of the spray-dried products to moisture vapor was monitored gravimetrically. Bovine liver catalase, bovine pancreatic insulin, and bovine pancreatic ribonuclease A when individually cospray-dried with lactose showed no extensive initial crystallinity by powder X-ray diffraction, but proteins cospray-dried with mannitol generally showed evidence of mannitol component crystallinity. Catalase appeared to inhibit lactose crystallization from an amorphous matrix to a greater extent than insulin when exposed to short-term elevated humidity, but this difference was a kinetic feature. The hygroscopicities of the cospray-dried materials differed and indicated that each protein/sugar system required individual characterization to identify an optimal formulation.

Catalase↗

PubMed1998

Classification of new phytoplasmas associated with diseases of strawberry in Florida, based on analysis of 16S rRNA and ribosomal protein gene operon sequences.

Strawberry plants exhibiting symptoms of stunting and abnormally small leaves were observed in production fields in central Florida, USA. Since the symptoms were suggestive of phytoplasma infection, plants were assayed for presence of phytoplasma by PCR amplification of 16S rDNA and ribosomal protein (rp) gene sequences. Amplification of phytoplasma-specific DNA sequences by PCR indicated infection of the diseased strawberry plants by phytoplasmas. RFLP analyses of amplified 16S rDNA revealed that the plants were infected by two mutually distinct phytoplasmas that differed from strawberry green petal phytoplasma (group 16Srl-C). Both phytoplasmas were members of 16S rRNA gene group I (16Srl). Based on RFLP analysis of amplified 16S rDNA and rp gene sequences, one was classified in group 16Srl subgroup I and new rp subgroup 16Srl-l(rp); its 16S rRNA-rp subgroup was designated 16Srl-K(rr-rp). The second phytoplasma represented a previously undescribed subgroup, designated K, in 16S rRNA group I but belonged to rp subgroup 16Srl-J(rp); this phytoplasma's 16S rRNA-rp subgroup was designated 16Srl-J(rr-rp). Results of RFLP analyses agreed with putative restriction site maps based on nucleotide sequences determined for the amplified 16S rDNAs and rp gene operon DNAs. Further evidence indicated that the 16Srl-K(rr-rp) strawberry phytoplasma, Mexican periwinkle virescence phytoplasma and stolbur phytoplasma shared sequence homologies that enabled amplification of DNA from all three by PCR using primers previously designed as stolbur-specific.

DNA Primers↗

PubMed1998

Human immunodeficiency virus type 1 in faeces and serum: evidence against independently evolving subpopulations.

It is not known whether independent tissue-specific evolution accounts for the differences between human immunodeficiency virus type 1 (HIV-1) subpopulations in intestinal tissue and blood. To study this, sequential serum samples from three persons were analysed for the presence of HIV-1 V3 genotypes which were detected exclusively in faeces at a specific time-point. For two persons the faeces genotype was found in serum samples collected before the time of faeces collection: 7 months for one person and 32 months for the other person. In the third person, serum collected 1 month after faeces collection contained the faeces genotype in abundance. These data indicate that a difference between intestinal tissue and blood HIV-1 subpopulations is not the result of complete compartmentalization and independent HIV-1 evolution in intestinal tissue, but that it reflects an unequal distribution of HIV-1 in different tissues.

Amino Acid Sequence↗

PubMed1998

Genetic differences between human immunodeficiency virus type 1 subpopulations in faeces and serum.

To study human immunodeficiency virus type 1 (HIV-1) compartmentalization between intestine and blood, paired faecal and serum samples were collected from 204 HIV-1-infected persons. Direct sequencing of the gp120 V3 region obtained from 33 persons showed that faecal and serum sequences could be nearly homologous (0.3% different) or very dissimilar (11.3% different). Individual clones were obtained and sequenced from the faecal and serum samples of 13 persons. In 6 persons the HIV-1 subpopulations in faeces and serum were similar, whereas in 7 persons, distribution of V3 genotypes showed a marked difference. Genetic characterization of the HIV-1 subpopulations showed less heterogeneity in faecal subpopulations than in serum subpopulations in 5 of the 7 subjects. Furthermore, faecal and serum subpopulations differed predominantly by nonsynonymous nucleotide substitutions (in 6 of 7 persons). Comparison of the HIV-1 subpopulations in faeces and serum of these 7 persons, using resampling techniques, revealed a significant difference between faecal and serum subpopulations at an N-linked glycosylation site, C-terminal of the V3 loop (amino acids 331-333). Sequences from faecal subpopulations of all 7 persons contained a glycosylation site at amino acid position 331-333. Four of these 7 harboured serum variants lacking a glycosylation site at this position. The faecal subpopulations in these 4 persons showed limited nonsynonymous substitutions compared to synonymous substitutions, indicating that purifying selection is operational on these subpopulations.

Acquired Immunodeficiency Syndrome↗

PubMed1998

Improved body distribution of 14C-labelled AZT bound to nanoparticles in rats determined by radioluminography.

The objective of the present study is to visualize differences in the body distribution between radiolabelled AZT bound to nanoparticles and a control solution. Polyhexylcyanoacrylate nanoparticles were manufactured by emulsion polymerization in the presence of AZT and an ionic emulsifier, bis(2-ethylhexyl) sulfosuccinate sodium. The AZT-control solution was equally prepared, but contained no monomer. The two preparations were administered either by i.v. injection or perorally by gavage. After determined time points the animals were sacrificed using carbon dioxide. The cadavers were shock-frozen in cellulose gel and cut into slices using a cryomicrotome. The tissue cross sections were fixed on an adhesive tape and then were freeze dried. The quantification of the radioactive AZT in the different organs and tissues was performed by radioluminography, and the images were generated on a computer. After i.v. injection of AZT-nanoparticles, a high amount of the AZT label was found in the organs belonging to the reticuloendothelial system. In these organs the radioactivity was inhomogeneously distributed showing that the uptake of the particle-associated radioactivity depended on the type of the cells located in the organs and was consistent with uptake by macrophages. The highest radioactivities were found in the GI-tract and in the liver. A difference in the elimination pathway between AZT-control solution and AZT bound to nanoparticles also was visible on the images. Similar results were obtained after oral administration. Of course, with the latter route a larger portion of AZT remained in the GI-tract especially after administration of nanoparticle-bound drug. These results confirmed those obtained by a classically performed quantitative whole body distribution study using liquid scintillation. This demonstrates that radioluminography is a useful method to study the organ distribution of drugs bound to nanoparticles.

Administration, Oral↗

PubMed1997

Effects of antimicrobial treatment at the end of lactation on milk yield, somatic cell count, and incidence of clinical mastitis during the subsequent lactation in a dairy herd with a low prevalence of contagious mastitis.

OBJECTIVE: To determine whether treating cows with antimicrobials at the end of lactation would lower the incidence of clinical mastitis, improve milk production, and decrease somatic cell count (SCC) in the subsequent lactation. DESIGN: Randomized blind field trial. ANIMALS: 233 Holstein cows from a single herd. All cows were in lactation 2 or greater. PROCEDURE: Cows were randomly assigned to treatment groups. Treated cows were given procaine penicillin G and novobiocin by intramammary infusion. Control cows were not treated. Farm personnel recorded cases of clinical mastitis. Milk yield and SCC were recorded during the subsequent lactation. RESULTS: Treatment did not significantly reduce the incidence of clinical mastitis when data for all cows were grouped or when data were stratified by lactation groups (lactation 2 vs lactation > or = 3) or by last SCC (< or = 500,000 cells/ml vs > 500,000 cells/ml). Somatic cell counts (first, mean of first 5, maximum of first 5) for treated and control cows were similar, and proportions of treated and control cows with SCC > 500,000 cells/ml at least once were not significantly different. Treated cows produced 179 kg (394 lb) more milk during the first 17 weeks of lactation than did control cows. CLINICAL IMPLICATIONS: Treating cows with antimicrobials at the end of lactation increased 17-week milk production during the subsequent lactation and, at current milk prices, was financially preferable to not treating them.

Analysis of Variance↗

PubMed1996

Diagnosis and therapy of aortic prosthetic fistulas: trends over a 30-year experience.

A retrospective study was carried out of patients from a single institution over a 30-year period. Thirty-one patients presented with 33 fistulas, four non-enteric and 27 enteric. In 25 of 27 patients with a prosthesis-related enteric fistula gastrointestinal bleeding was present. Angiography revealed the fistula in five patients endoscopy in three, and barium studies, echography and computed tomography each revealed one fistula. Six patients died before and five died during operation. In 20 patients various techniques were used for treatment. In-hospital mortality decreased from six of eight patients before 1970, to seven of ten between 1971 and 1980, and to four of 13 after 1981. In the long term, patients treated with an extra-anatomic reconstruction had a poorer prognosis than those treated by in situ reconstruction. This experience shows that diagnostic tests often fail to reveal a prosthesis-related fistula and that mortality can be substantially reduced by early exploration in patients with negative diagnostic studies.

Adolescent↗

PubMed1996

Comparison of the reappearance of strongyle eggs on foals, yearlings and adult horses after treatment with ivermectin or pyrantel.

The reappearance of strongyle eggs in faeces after treatment with ivermectin or pyrantel embonate was investigated in 22 foals, 36 yearlings, and 45 adult horses on five Dutch horse farms. The results confirmed earlier studies which showed an egg reappearance period of 9 and 6 weeks after ivermectin and pyrantel treatment, respectively. There were no differences between the egg reappearance periods of foals, yearlings, and adult horses. The mean egg counts of the yearlings were, however, consistently higher than the mean egg counts of the adult horses and foals in both ivermectin- and pyrantel-treated animals. It is concluded that shorter treatment intervals in foals and yearlings are not obligatory. However, longer intervals must be prevented in yearlings because their contribution to pasture contamination is relatively high.

Age Factors↗