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Biomedical subjects

P Lanthier

Publications and source records attributed to P Lanthier.

8 recordsLinked to original sources
PubMed2001

Characterization of cellobiohydrolase I (Cel7A) glycoforms from extracts of Trichoderma reesei using capillary isoelectric focusing and electrospray mass spectrometry.

Capillary isoelectric focusing (CIEF) was used to profile the cellulase composition in complex fermentation samples of secreted proteins from Trichoderma reesei. The enzyme cellobiohydrolase I (CBH I, also referred to as Cel7A), a major component in these extracts, was purified from different strains and characterized using analytical methods such as CIEF, high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD), and capillary liquid chromatography-electrospray mass spectrometry (cLC-ESMS). ESMS was also used to monitor the extent of glycosylation in CBH I isolated from T. reesei strain RUT-C30 and two derivative mutant strains. Selective identification of tryptic N-linked glycopeptides was achieved using LC-ESMS on a quadrupole/time-of-flight instrument with a mixed scan function. The suspected glycopeptides were further analyzed by on-line tandem mass spectrometry to determine the nature of N-linked glycans and their attachment sites. This strategy enabled the identification of a high mannose glycan attached to Asn270 (predominantly Man8GlcNAc2) and single GlcNAc occupancy at Asn45 and Asn384 with some site heterogeneity depending on strains and fermentation conditions. The linker region of CBH I was shown to be extensively glycosylated with di-, and tri-saccharides at Thr and Ser residues as indicated by MALDI-TOF and HPAEC-PAD experiments. Additional heterogeneity was noted in the CBH I linker peptide of RUT-C30 strain with the presence of a phosphorylated di-saccharide.

Amino Acid Sequence↗
PubMed1999

Acute watery diarrhea as the initial presenting feature of a pheochromocytoma in an 84-year-old female patient.

We report the case of an 84-year-old woman who was initially admitted to the emergency room of our institution for frank dehydration caused by acute and severe secretory diarrheas along with acidosis and hypokalemia. After extensive gastrointestinal investigations, the etiology of the diarrhea remained unclear. Because clinical symptoms and ionogram parameters worsened, despite intravenous fluids and electrolyte replacement, an abdominal CT scan was performed and unexpectedly revealed a 4.5-cm mass in the right adrenal gland. Several separate 24-hour urine catecholamines were shown to be highly elevated. The diagnosis of pheochromocytoma was confirmed by MIBG scintigraphy and MRI. Before the admission, the patient never experienced symptoms suggestive of pheochromocytoma, except dry mouth and fear of impending death on several occasions. After 2 weeks, the diarrhea stopped abruptly and spontaneously without specific medication but after adequate rehydration. The patient subsequently underwent surgical removal of the adrenal medullary mass. Postoperatively, urinary catecholamines returned to normal values. Immunohistochemical study of the tumor confirmed the diagnosis of pheochromocytoma and revealed the presence of VIP-positive cells organized as islets in scattered areas of the tissue. This case illustrates the protean mode of presentation of pheochromocytoma, as well as the ability of medullary neural crest-derived cells to produce various neuropeptides potentially responsible for a large variety of symptoms.

Acute Disease↗
PubMed1995

Lignin oxidation by laccase isozymes from Trametes versicolor and role of the mediator 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonate) in kraft lignin depolymerization.

Two laccase isozymes (I and II) produced by the white-rot fungus Trametes versicolor were purified, and their reactivities towards various substrates and lignins were studied. The N-terminal amino acid sequences of these enzymes were determined and compared to other known laccase sequences. Laccase II showed a very high sequence similarity to a laccase which was previously reported to depolymerize lignin. The reactivities of the two isozymes on most of the substrates tested were similar, but there were some differences in the oxidation rate of polymeric substrates. We found that the two laccases produced similar qualitative effects on kraft lignin and residual lignin in kraft pulp, with no evidence of a marked preference for depolymerization by either enzyme. However, the presence of the mediator 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonate) prevented and reversed the polymerization of kraft lignin by either laccase. The delignification of hardwood and softwood kraft pulps with the two isozymes and the mediator was compared; either laccase was able to reduce the kappa number of pulp, but only in the presence of 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonate).

Amino Acid Sequence↗
PubMed1989

Colonic angiodysplasia. Follow-up of patients after endoscopic treatment for bleeding lesions.

Endoscopic electrocoagulation or photocoagulation is now the method of choice for treating colonic angiodysplasia. Follow-up of such patients has not been extensive. The authors report 26 patients with typical and symptomatic lesions who have been treated endoscopically. Follow-up (mean duration, 29.3 months) revealed that 21 patients remained symptom-free after a single procedure. Two patients needed a second procedure before being considered cured. In two others, the need for transfusions was lessened considerably after treatment. The last patient died of terminal cardiac failure. No complications occurred during treatment. Endoscopic treatment is a safe and efficient method for treating bleeding colonic angiodysplasia.

Adolescent↗
PubMed1987

[Solitary lesions of the rectum caused by suppositories combining acetylsalicylic acid and paracetamol].

The reports of 8 female patients who, because of recurrent headache, were using analgesic suppositories containing acetylsalicylic acid and paracetamol (Perdolan) for more than two years are analyzed. Symptoms were nonspecific: anal pain, rectal tenesmus or bleeding. The lesions were located within 8 cm from the anal verge and consisted of superficial ulcerations, fibrotic scar tissue and rectal stenosis. Biopsies showed non-specific inflammation, limited to the rectum. Rectal prolapse or intussusception was not associated. By discontinuing the use of suppositories, symptoms usually resolved; rectal stenoses required anorectal dilatations and in 2 cases surgical resection. When solitary rectal lesions are observed in the absence of rectal prolapse, chemical aggression of the rectal mucosa by use of suppositories containing acetylsalicylic acid should be considered.

Acetaminophen↗
PubMedDate not supplied

Francisella tularensis proteome: low levels of ASB-14 facilitate the visualization of membrane proteins in total protein extracts.

Proteomic analysis of bacterial pathogens isolated from in vivo sources, such as infected tissues, provides many challenges not the least of which is the limited quantity of sample available for analysis. It is, therefore, highly desirable to develop a one-step cellular lysis and protein solubilization method that minimizes protein losses and allows the maximum possible coverage of the proteome. Here, we have used standard sample buffer constituents including urea, thiourea and DTT, but varied the detergent composition of the buffers in order to achieve the best quality of gels and the greatest spot resolution. We found that the most efficient solubilizing solution in this case consisted of 7 M urea, 2 M thiourea, 1% DTT, 0.5% amidosulfobetaine-14 (ASB-14) and 4% 3-[(3-Cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS). Inclusion of low levels of ASB-14 in solutions allowed visualization of a subset of 24 new protein spots in the Live Vaccine Strain (LVS) of Francisella tularensis and 21 spots in a virulent A-strain of the pathogen. Further investigation showed that 15 of the 24 enriched LVS spots were membrane or membrane-associated proteins suggesting that the optimized lysis and solubilization solution aids in the detection of more hydrophobic proteins. This methodology is now being applied to the analysis of Francisella obtained from in vivo sources.

Bacterial Proteins↗