Biomedical subjects
Publications and source records attributed to C Collet.
The gene coding for the late lactation protein (LLP) in Macropus eugenii has been mapped using in situ hybridization to the proximal region of the long arm of chromosome 3. This position was confirmed by means of exclusion Southern blot analysis.
Analysis of the tammar wallaby beta-lactoglobulin cDNA and inferred amino acid sequences reveal extensive sequence divergence from the eutherian beta-lactoglobulins. Conserved residues include the cysteines and a number of individual amino acids involved in structure and ligand-binding. The only region of extended similarity is a heptapeptide sequence which may impart specificity to its interaction with a receptor protein. Northern analysis of total mammary RNA revealed two transcripts which result from differential utilization of polyadenylation signals. The concentration of beta-lactoglobulin mRNA increased in late lactation and correlates with increases in milk production and levels of milk fat. Quantification of beta-lactoglobulin mRNA levels in hormone-stimulated mammary gland explants from tammars in late pregnancy suggests that maximal induction of the gene is dependent on prolactin alone and that expression is not modulated by other hormones known to play a role in the initiation of lactation in eutherians.
The authors report a case of two siblings who developed a neonatal alloimmune thrombocytopenia (NAITP) due to Bak-System incompatibility. They review the platelet antigen systems involved in NAITP and raise the problem of its present antenatal and postnatal management.
The gene for alpha-lactalbumin has been cloned from a tammar wallaby (Macropus eugenii) mammary gland cDNA library. Tammar alpha-lactalbumin has approximately 50 and 30% homology to the alpha-lactalbumins of eutherians at the levels of nucleotide and protein sequence respectively. Comparison of the inferred tammar polypeptide sequence with the sequence of the eutherian proteins reveals extensive divergence at almost all of the non-essential amino acid residues. However, the hydropathy plots of the tammar protein are almost identical to those of eutherian alpha-lactalbumins, suggesting that protein conformation is conserved. The tammar gene encodes a transcript of approximately 975 bases. Northern blot analysis of hormone-stimulated mammary gland explants shows that maximal induction of alpha-lactalbumin mRNA is dependent on prolactin and that expression is not modulated by other hormones that play a role in the initiation of lactation in eutherians.
Genomic clones containing sequences homologous to an esterase 6 (Est-6) cDNA clone were isolated from a library of Drosophila melanogaster DNA. Comparison of the genomic and cDNA sequences revealed that the Est-6 gene comprises two exons, one of 1,387 bp and one of 248 bp, separated by a short intron of 51 bp. Further sequencing revealed the presence of a tandem duplication of the Est-6 gene (denoted Est-P) which also has an exon of 1,387 bp and an exon of 248 bp, separated by a short intron of 56 bp. The two genes show similarities of 64% and 60% at the DNA and protein levels, respectively. The coding regions of the genes are 197 bases apart, and presumptive 5' regulatory sequences of Est-P overlap at least the 3' noncoding region of Est-6. Transcripts homologous to Est-P were detected in late larvae and adults of each sex, whereas Est-6 transcripts are present in all life stages but are predominant in adult males. This suggests different physiological functions for the products of the two genes. Southern and Northern blot hybridization analyses of the 20-kb region surrounding the Est-6/Est-P duplication failed to detect any other duplicated esterase genes, although this region is actively transcribed.
The tammar wallaby (Macropus eugenii) produces two different types of milk; "early" milk for the first 180 days and "late" milk for the remaining 150 days of lactation. We report the cloning of the cDNA of a novel whey protein, Late-Lactation Protein (LLP), which is produced during the late phase of lactation. The cDNA was cloned using an oligonucleotide probe deduced from the published partial protein sequence. The cDNA encodes an open-reading frame of 176 amino acids of which the first 18 residues represent a signal peptide. Northern blot analysis revealed a 1kb transcript in late phase lactation but not in the early phase.
The nucleotide sequence of the Fast-Chateau Douglas isolate of the thermostable alcohol dehydrogenase allele is compared with the sequences of the Slow and Fast alleles of Drosophila melanogaster. Conceptual translation of the FChD sequence indicates that the thermostable polypeptide has the diagnostic FAST amino acid replacement at residue 192 and an additional replacement of serine for proline at residue 214. This suggests a Fast origin for the thermostable Adh allele. However, some of the biochemical properties of the FCHD protein resemble those of the SLOW rather than the FAST polypeptides. The serine for proline replacement confers upon the thermostable polypeptide substrate specificities and some kinetic parameters similar to the SLOW protein. The same replacement substitution within the third coding exon also appears to alter the ADH protein concentration to a level similar to the SLOW polypeptide and the probable effect is at the level of mRNA concentration. The low level of nucleotide sequence variation, other than that leading to the amino acid substitution, suggests a recent origin for the thermostable allele. The time since divergence of the FChD sequence from Fast is estimated to be approximately 260,000-470,000 years.
Twenty two patients with transitional cell bladder carcinoma (T greater than or equal to 2 Mo) received 2 or 3 courses of systemic chemotherapy (cyclophosphamide 600 mg/m2, doxorubicin 60 mg/m2, cisplatinum 100 mg/m2) prior to total (18) or partial (18) cystectomy. Response rate was appreciated on the pathologic findings of the surgically removed bladders (pTNM): 5 tumor progression (23%); 8 tumor stability (36%); 3 partial remission (14%); 4 complete remission (18%), 2 pTo after complete transurethral resection (9%). These results lead us to conclude that: the rate of tumor progression and stability was too high. Further experience will require a more effective preoperative treatment; clinical staging dramatically underestimates tumor spread; prognosis of non responders is quite poor: 7 deaths with a maximum follow-up of 6 months.
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The woodrush genus Luzula is characterised by having holocentric chromosomes. DNA of nine related Australasian species shows similar satellite DNAs which re very similar in nucleotide sequence content and unit length. Differences between the repetitive DNAs are evident as either the presence or absence of particular restriction enzyme sites. Sequence variants have probably been introduced into the repeated DNA components of ancestral species and particular variants reamplified during the evolution of the genus. Sequence amplification appears to be restricted to sequences already present in the genome rather than the de novo generation of repeats. The evolution of highly-repeated DNA sequences dispersed throughout the holocentric chromosomes of Luzula thus appears to be very similar to that known in eukaryotes with the more normal monocentric chromosome organisation.
The Est-6 gene of Drosophila melanogaster was cloned by screening libraries with synthetic oligonucleotides corresponding to tryptic peptides from purified esterase-6 (Est-6) protein. cDNA clones were isolated that hybridized in situ to the site of Est-6 on chromosome 3 at 69A1. Inserts in putative Est-6 cDNA clones were 1.85 kilobases (kb) long, and blot hybridization analysis of electrophoretically fractionated RNA, using a cDNA clone as a probe, revealed two transcripts, of 1.68 and 1.83 kb. The two transcripts showed the same developmental profile as the Est-6 protein. Neither transcript was detected in an Est-6-null line. The cDNA fragment was homologous to a 2.3-kb EcoRI-BamHI fragment in genomic clones, and this region was interrupted by the 8-kb B104 transposable element in the Est-6-null line. Conceptual translation of the cDNA sequence revealed a protein of 548 residues with 19% sequence similarity to acetylcholinesterase from the Torpedo ray.
A retrospective study was carried out on 96 partial hip prostheses. Results of this study led us to define new radiological criteria for evaluation of the anatomical position of the prosthetic cup in the acetabulum. A method of measurement of the migration of the prosthetic cup in the acetabulum is proposed based on the results of roentgenological and anatomical study. The anatomical landmarks, geometric constructions and methods of computation of such measurement are described. The application of this technique to radiological/anatomical study was found to be reliable and allowed the determination of prognostic factors indicative of poor acetabular tolerance of the prosthetic cup.
The aim of this article was to question the classical inverted-U curve relationship between activation and performance. It was hypothesized that changes in performance were related to both activation and the degree of skill difficulty, suggesting a more complex relation. Fifty-one subjects took part in one of three experiments requiring sensory and motor anticipation abilities. They were divided into three different groups, each performing one particular anticipation task. Skin resistance was continuously recorded during task performance. This autonomic variable is well known to be a reliable index in predicting activation variations. The first task, carried out in a seated position, was to intercept a moving spot on a computer screen by pressing the space bar on the keyboard. The second task, performed standing, required subjects to intercept a moving table tennis ball with palm of the hand, by extending the forearm and the arm. The third task, executed in movement was performed on a volley-ball ground. The aim was to hit a ball to reach a moving human target, using the forearm-blow technique. Results showed that 90.9% of subjects'performance in Experiment 1 was related to skin resistance tonic level variations, thus establishing a strong relationship between performance and arousal. Subjects' performance (43.8%) in Experiment 2 was related to skin resistance tonic level variations, whereas only 12.5% of performance was related to this variable in Experiment 3. In conclusion, tonic level variations can only account for success or failure in the first experiment. Conversely, success or failure were dependent upon information processing, decision making, and motor execution in the third experiment. The second experiment, requiring intermediate abilities, was found to show intermediate results. The role of skin resistance tonic level fluctuations and their use in the study of sporting performance are discussed, suggesting that arousal/performance relationships do not correspond to a simple inverted-U curve in complex motor skills requiring a steady level of arousal.
Two of the dominant whey proteins of the tammar wallaby, beta-lactoglobulin (BLG) and late lactation protein (LLP), have been positively identified on gradient polyacrylamide gradient gels by N-terminal protein sequencing. The origin of the electrophoretic variation present in these proteins has been found to be principally genetic. The variation was examined in 97 lactating female tammar wallabies, of which 10 were followed throughout lactation to determine if any developmental variation existed. The only distinguishable developmental difference results from the previously described appearance of LLP at the beginning of phase III of lactation (approximately 180 days after birth of the young). Electrophoretic analysis of BLG implies that it exists in monomeric, dimeric, and tetrameric forms. Very strong linkage disequilibrium, indicative of close linkage, was found between alleles at the Blg and Llp loci. Examination of their cDNA sequences suggests that LLP and BLG represent an ancient gene duplication. Both have conserved amino acid residues characteristic of the lipocalins. The results imply that the marsupial mode of lactation, and hence of reproduction, is also very ancient.
We report a case of hepatic and splenic angiosarcoma in a 34 year-old man presenting with hemoperitoneum and consumption coagulopathy. Histological and immunohistological diagnosis was based on a biopsy specimen obtained through the transjugular route. Embolization via the splenic artery for the most significant lesions and intravenous chemotherapy resulted in a partial response in the liver and splenic tumour masses and survival with a good quality of life. The initial complications recurred after chemotherapy was stopped and death occurred after 15 months. The benefit of arterial embolization and chemotherapy in this rare and usually rapidly fatal disease should be assessed in other patients.
This report describes the results of a multicentric study of biological methods for luteinizing hormone (hLH). The production of testosterone by animal Leydig cells is used by five laboratories with different methodologies including rat, mouse and pig cells. Dose-response curves of testosterone production, quality criteria and results on a physiological population of men and women, are reported and discussed. It is concluded that the bioactive determination of hLH must be considered as a reference method used in discordances between clinic and immunological methods.