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  • 1
    ISSN: 1432-0738
    Keywords: Lead ; Rabbit ; Chronic exposure ; Biochemical effects ; Clinical effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effect of chronic subcutaneous administration of lead acetate was studied in female rabbits. The low-dose group (15 animals) received three times a week 0.10–0.20 μg/kg body weight and the high-dose group (15 animals) 0.80–1.20 μg/kg. The control group received the vehicle only. Concentrations of lead in blood in the low-dose group increased to ca. 400 μg/l after 70 days and in the high-dose group to ca. 900 μg/l after 110 days. After 7.5 months eight animals of each group were sacrificed. The remaining rabbits were kept for an additional 4 months without treatment. Blood lead concentrations decreased with a half-time of 60–70 days. During exposure the gain in body weight was lower in the high-dose group than in the control group and the low-dose group. The high-dose group developed slight anaemia and low MCV, MCH and MCHC, and basophilic stippling of erythrocytes. These effects disappeared during recovery. ALAD activity in erythrocytes was very low during exposure in both exposed groups and did not reach control values during recovery. During exposure the concentrations of ZPP and ALA-U increased, but only ALA-U returned to normal during recovery. No other effects of lead on the composition of the urine were observed. No effects were observed on plasma urea and creatinine concentrations. In the highdose group the concentration of ALAD in the liver decreased by 30%. During recovery this effect was no longer present. No effects were seen in cytochrome P-450 content or cytochrome P-450-dependent enzyme activities. Lead was mainly stored in bones, but some also in serveral soft tissues. After recovery the concentrations in soft tissues decreased to a variable degree. In the high-dose group the relative weights of heart and liver increased. These effects disappeared during recovery. At 400 μg lead/l blood no adverse effects were observed that did occur at the high dose level.
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  • 2
    ISSN: 1432-0738
    Keywords: Congenic ; Syrian hamster ; N-acetyltransferase ; N-acetylation ; Acetylator genotype
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Our laboratory recently reported the successful construction of homozygous rapid (Bio. 82.73/H-Pat r) and homozygous slow (Bio. 82.73/H-Pat s) acetylator congenic Syrian hamsters. These hamsters are isogenic except for the polymorphic acetylator gene locus (Pat) and perhaps other closely linked loci. The purpose of the present investigation was to assess the expression of acetylator genotype both in vivo and in vitro in a variety of hepatic and extrahepatic organ cytosols. Levels of arylamine N-acetyltransferase were generally high and in the relative order: liver 〉 colon 〉 kidney 〉 pancreas 〉 prostate, urinary bladder, and lung. However, an acetylator gene dose-response was clearly expressed in each tissue, with highest levels in homozygousPat r acetylators, intermediate levels in heterozygousPat r/Pat s acetylators, and lowest levels in homozygousPat s acetylators. The magnitude of the acetylator genotype-dependent differences in N-acetyltransferase activity were substrate specific, whereinp-aminobenzoic acid showed the largest differences andp-aminophenol the smallest. The N-acetylation ofp-aminobenzoic acid in vivo also reflected acetylator genotype in the congenic hamsters. These results further document the successful construction of rapid and slow acetylator congenic hamsters which should prove very valuable in future studies to assess the role of acetylator genotype in the toxicity and carcinogenicity of arylamine chemicals.
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  • 3
    ISSN: 1432-0738
    Keywords: Colorectal cancer ; Acetylator genotype ; Human colon ; Arylamine N-acetyltransferase ; Age effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Polymorphic expression of arylamine N-acetyltransferase (EC 2.3.1.5) may be a differential risk factor in metabolic activation of arylamine carcinogens and susceptibility to cancers related to arylamine exposures. Human epidemiological studies suggest that rapid acetylator phenotype may be associated with higher incidences of colorectal cancer. We used restriction fragment length polymorphism analysis to determine acetylator genotypes of 44 subjects with colorectal cancer and 28 non-cancer subjects of similar ethnic background (i.e., approximately 25% Black and 75% White). The polymorphic N-acetyltransferase gene (NAT2) was amplified by the polymerase chain reaction from DNA templates derived from human colons of colorectal and non-cancer subjects. No significant differences inNAT2 allelic frequencies (i.e., WT, M1, M2, M3 alleles) or in acetylator genotypes were found between the colorectal cancer and non-cancer groups. No significant differences inNAT2 allelic frequencies were observed between Whites and Blacks or between males and females. Cytosolic preparations from the human colons were tested for expression of arylamine N-acetyltransferase activity. Although N-acetyltransferase activity was expressed for each of the arylamines tested (i.e., p-aminobenzoic acid, 4-aminobiphenyl, 2-aminofluorene, β-naphthylamine), no correlation was observed between acetylator genotype and expression of human colon arylamine N-acetyltransferase activity. Similarly, no correlation was observed between subject age and expression of human colon arylamine N-acetyltransferase activity. These results suggest that arylamine N-acetyltransferase activity expressed in human colon is catalyzed predominantly by NAT1, an arylamine N-acetyltransferase that is not regulated byNAT2 acetylator genotype. The ability to determine acetylator genotype from DNA derived from human surgical samples should facilitate further epidemiological studies to assess the role of acetylator genotype in various cancers.
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  • 4
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cystic fibrosis (CF) patients (n = 157) from the GDR were analysed for the occurrence of the recently discovered 3bp deletion causing CF. About 50% of all investigated patients were homozygotes and about 30% heterozygotes for this deletion. Of the analysed CF chromosomes from these patients, 62% carry the deletion, which is in strong linkage disequilibrium with the KM19 restriction fragment length polymorphism allele 2 and the 1/2 XV2c/KM19 haplotype.
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  • 5
    ISSN: 1432-1211
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract To investigate the class I major histocompatibility complex (MHC) genes expressed in the young sheep thymus, a cDNA library was screened with a human HLA-B7 cDNA probe under conditions of relaxed stringency. Thirteen clones were isolated and found by partial sequences to fall into five classes, requiring the expression of at least three loci. One sequence was found six times, almost half of the total, and may thus represent the major message expressed in the young sheep thymus. One of the clones was found to have failed to excise the intron between cytoplasmic exons 7 and 8, leading to the predicted synthesis of a cytoplasmic domain 23 amino acids longer than the other sheep sequences, and 15 amino acids longer than any cytoplasmic domain previously described. The sequences of all the clones were found to be most similar to bovine, and least similar to mouse class I MHC sequences.
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  • 6
    ISSN: 1432-1106
    Keywords: Optokinetic nystagmus ; Ferret ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aim of this study was to evaluate the functional significance of similarities observed in the anatomy and the physiology of cat and ferret visual systems. Optokinetic nystagmus (OKN) in response to movement of the entire visual field, and optokinetic after nystagmus (OKAN) were measured in 8 ferrets with binocular stimulation. A shift of the beating field in the same direction as the fast phase of eye movements was observed both in ferret and cat. The absence of a fast rise in slow phase velocity (SPV) and similarities in the time constant to reach the steady state OKN gain, using step velocity stimuli are noted. As in the cat, primary OKAN was observed with a gradual decrease in its SPV. Following termination of stimulation, no sudden fall in SPV was noted for either species. However, for the ferret, the decrease was more rapid. With monocular stimulation, small differences were observed in OKN gain when responses to temporonasal and nasotemporal directions of the stimulus were compared in the two species. In contrast, the ferret displays a OKN gain which is approximatively twice that of the cat at stimulus velocities of 100°/sec. Even at 200°/sec., visual movement still induces a discernable OKN response (gain.0.07). Secondary OKAN, always present in the cat, was observed in only 43% of ferret records. Taken together with other considerations, these findings recommend the ferret as an alternative to the cat for the study of OKN and of other visuo-motor capacities in carnivores.
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  • 7
    ISSN: 1432-1211
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
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  • 8
    ISSN: 1432-2277
    Keywords: Pancreas transplantation, computed tomography ; Kidney-pancreas transplantation, computed to mography ; Computed tomography, kidney-pancreas transplantation ; Pancreatitis, computed tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In a prospective study, 17 early baseline computed tomography (CT) scans were obtained 2 or 3 days after simultaneous kidney-pancreas transplantation. Morphological changes and their relevance to the early detection of graft rejection and complications were evaluated. The pancreatic grafts were enlarged and showed signs of mild pancreatitis. Serial scans obtained during the first renal graft rejection episode were compared with the baseline CT scans (n=7). They showed a significant increase in pancreatic graft size in the case of biopsy-proven severe renal graft rejection (P=0.008). Normally functioning pancreatic allografts showed a 15%–40% decrease in size 1–6 months after transplantation. We conclude that the morphological changes observed early after transplantation are compatible with mild pancreatitis, which may contribute to the development of pancreatic graft thrombosis. There is an increase in the number of morphological changes during severe rejection, yet enlarged pancreatic grafts appear to recover from transplantation-related damage and regain their normal size without signs of atrophy.
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  • 9
    ISSN: 1432-5195
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Nous avons eu recours, pour allonger les membres inférieurs, à la méthode d'Ilizarov de distraction épiphysaire depuis 1977 et à sa nouvelle technique de corticotomie ou compactotomie depuis 1983. La première méthode a été utilisée pour 22 membres inférieurs avec un allongement moyen de 8.25 cm (de 4 à 18 cm). Sont inclus dans ce groupe deux achondroplases chez qui les deux membres inférieurs ont été allongés de 12 cm. Dans la deuxième méthode on pratique une corticotomie au niveau de la jonction dia-métaphysaire, suivie d'une distraction avec l'appareil d'Ilizarov (4×0.25 mm par jour). Nous avons allongé 30 membres inférieurs, parmi lesquels 5 patients qui ont eu un allongement bilatéral compris entre 8 et 12 cm. Chez les autres on a obtenu un allongement moyen de 7.9 cm (de 4 à 15 cm). Le rapport entre la durée du traitement par cm obtenu (c'est à dire le temps écoulé entre l'opération et la mise en charge complète divisé par le nombre de cm d'allongement) est plus faible après distraction epiphysaire qu'après corticotomie. Les complications sont également un peu moins fréquentes avec cette dernière technique. La distraction épiphysaire doit être réservée aux enfants, de l'âge de 12 ans jusqu'à la fin de la croissance. L'avantage de la corticotomie est qu'elle peut être effectuée à n'importe quel âge, de 5 à 30 ans. Dans les deux cas, il faut prendre le plus grand soin pour éviter les complications.
    Notes: Summary We have used Ilazorov's method of distraction epiphyseolysis for leg lengthening since 1977 and his new method of corticotomy or compactotomy since 1983. The first method was carried out in 22 lower limbs with an average lengthening of 8.25 cm (range 4 to 18 cm); included in this group are 2 patients with achondroplasia in whom both legs were lengthened 12 cm. In the second method, a corticotomy is carried out at the metaphyseal-diaphyseal junction followed by distraction in Ilazorov's apparatus (4×0.25 mm a day). We lengthened 30 legs; included are 5 patients who had both legs lengthened from between 8 and 12 cm. In the remainder an average of 7.9 cm of lengthening was achieved (range from 4 to 15 cm). The index for the treatment time per cm achieved (time from operation until full weight-bearing per cm of lengthening) was shorter after distraction epiphyseolysis than after corticotomy. Complications were also a little less after the latter procedure. Distraction epiphyseolysis has to be limited to children from aged 12 years until growth ceases. The advantage with corticotomy is that it can be done at any age from 5 to 30 years. Care is needed in both cases to avoid complications.
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  • 10
    ISSN: 1433-0350
    Keywords: Magnetic resonance imaging ; Shunt malfunction ; Cerebrospinal fluid shunt ; Cerebrospinal fluid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Shunt malfunction is common and its diagnosis may require invasive testing that may be inaccurate or result in complications. Magnetic resonance imaging (MRI) may prove to be a useful noninvasive test of shunt function as it has been shown that MRI is capable of measuring cerebrospinal fluid (CSF) flows from 2 ml/h to 40 ml/h in model systems. Since flows in functioning shunt systems can be less than 2 ml/h, MRI must be sensitive enough to detect flow in this range in order to be a valid test for shunt function. Continuing previous studies, we have studied MRI flow-related enhancement at flow rates from 0 to 2 ml/h. Multiple spin echo scans (TR2000, TE20) were made through a specialized section of tubing in a model shunt system. The intensity of the MRI signal at points known to demonstrate maximal flow-related enhancement was measured. A linear relationship was demonstrated between signal intensity and flow as low as 0.8 ml/h. These results add support to the concept that MRI is sensitive enough to detect the lowest flows present in functioning shunt systems and therefore may be useful as a noninvasive test of shunt function.
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