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Biomedical subjects

M Martin

Publications and source records attributed to M Martin.

At least 361 records · Page 20Linked to original sources
PubMed1995

Expression of functional ricin B chain using the baculovirus system.

The ricin B chain (RTB) was expressed using a baculovirus expression system. The RTB coding sequence downstream of the preproricin signal sequence was inserted in the baculovirus transfer vector pM34T. After cotransfection of Spodoptera frugiperda Sf9 cells with linearized baculovirus DNA, recombinant viruses were selected, cloned and amplified. Upon infection of Sf9 cells with these recombinant baculoviruses, RTB production was revealed by immunoblotting. RTB expression using this system was optimum 72 h after infection of the cells at a multiplicity of infection of 3. RTB produced was glycosylated and had an apparent molecular mass of 34 kDa. Most of the signal sequence was removed, but the resulting recombinant RTB had a 13-residue N-terminus extension. Immunofluorescence analysis showed that this protein was located in the endoplasmic reticulum/Golgi region of the cell. RTB was not present at the plasma membrane. Secretion was enhanced by the addition of lactose to the cell-culture medium up to 50 mM. Purification was achieved from both cells and media using immobilized lactose and the lectin activity of RTB. Results obtained with the purified recombinant protein (more than 2 mg/l culture) were identical to those obtained with native RTB in all assays for biological activity; binding, internalization and reassociation with the ricin A chain to produce toxic ricin. Moreover, the RTB translocation capacity was not altered by the N-terminal peptide, showing that recombinant RTB could be used to deliver antigenic peptides to the cytosol for the induction of cell-mediated immunity.

Amino Acid Sequence↗
PubMed1995

Innovative HIV/AIDS program launched in Ottawa.

Collaboration among 31 social and health care agencies and the provincial government has resulted in an innovative program for Ottawa-area patients with HIV infection or AIDS. The target group is the homeless and people with "unstable" housing who live in the city's downtown core, a group at high risk of contracting HIV. The education of family practitioners will be an important part of the program.

HIV Infections↗
PubMed1995

Quebec hopes to overcome province's surgical-delay problem.

The Quebec government has released an action plan for eliminating delays in surgery in the province. One of the main goals is to increase the amount of day surgery, thus reducing the demands on hospitals. While most physician groups appear to support the plan, the Quebec Hospital Association wonders whether the follow-up community care needed to support the day surgery will be available.

Aftercare↗
PubMed1995

An augmented escape of androstenedione from suppression by dexamethasone in melancholia: relationships to intact ACTH and cortisol nonsuppression.

To further examine the association between basal and postdexamethasone (DST) pituitary and adrenal activity in depression, the authors measured intact adrenocorticotropic hormone (ACTH), androstenedione and cortisol, both in baseline and post-DST conditions, in 63 depressed subjects (14 minor, 33 simple major and 16 melancholic subjects). It was found that post-DST androstenedione, cortisol and ACTH values were significantly higher in melancholic than in minor depressed subjects. There were highly significant correlations between plasma androstenedione and ACTH both in baseline and post-DST conditions. The significant intercategory differences in post-DST androstenedione were determined by differences in post-DST ACTH. Basal and post-DST androstenedione values were significantly higher in men than in women and both values were significantly and negatively related to age. There were highly significant, positive relationships between cortisol and ACTH and between cortisol and androstenedione both in baseline and post-DST conditions. The results corroborate our hypotheses that, in depression, pituitary (ACTH) and adrenal (cortisol and androstenedione) hormonal secretion are tightly coupled in post-DST conditions and that the augmented escape of ACTH-target hormones in melancholia is, in part, related to that of pituitary ACTH.

Adrenocorticotropic Hormone↗
PubMed1995

Comparative analysis of 13C-enriched metabolites released in the medium of cerebellar and cortical astrocytes incubated with [1-13C]glucose.

Rat cerebellar and cortical astrocytes cultured for 15 or 35 days were incubated with [1-13C]glucose in the presence or absence of 4 mM exogenous glutamine and the release of 13C-enriched metabolites into cell media was studied by 13C-NMR spectroscopy. In the presence of exogenous glutamine, both cerebellar and cortical astrocytes consumed the amino acid. In contrast, a net production of glutamine occurred in the absence of the amino acid. Simultaneously, a release of 13C-enriched glutamine into cell media was observed and was higher in the presence than in the absence of exogenous glutamine. This demonstrated the occurrence of an isotopic-exchange process which may involve a futile cycle at the level of glutamine synthetase and glutaminase activities. The 13C-enrichment ratio between glutamine carbons C2 and C3 was close to 1 in the presence of exogenous glutamine whereas it was higher than 1 in its absence, indicating that pyruvate carboxylase was more active in the absence of glutamine. In addition to glutamine, alanine was synthesized and exported into the medium of both cerebellar and cortical astrocytes. In contrast, citrate was specifically produced by cortical astrocytes. Slight increases in alanine and glutamine productions were observed for cortical astrocyte cultures between 15 and 35 days, whereas the amino acid production by cerebellar astrocytes increased several-fold after 35 days compared with that at 15 days of culture.

Alanine↗
PubMed1995

Isolation of a cDNA encoding a novel human FK506-binding protein homolog containing leucine zipper and tetratricopeptide repeat motifs.

Reduced-stringency PCR was used to isolate a cDNA encoding a novel human FK506-binding protein (FKBP) homolog. The encoded 38-kDa protein (FKBPr38) contains at its N-terminus a domain that is 33% identical to FKBP12. FKBPr38 is a member of a subclass of immunophilins, whose other members include FKBP52 and CyP40 (cyclophilin 40), that contain a three-unit tetratricopeptide repeat (TPR). In addition, FKBPr38 contains a consensus leucine-zipper repeat. The presence of the TPR domain and leucine zipper suggest that FKBPr38 may form homo-multimers or interact with other, as yet unidentified, proteins.

Amino Acid Isomerases↗
PubMed1995

Long-term trends in DDT, polychlorinated biphenyls, and chlordane in California mussels.

The California State Mussel Watch program is a long-term monitoring program conducted by the State Water Resources Control Board and the Department of Fish and Game. In a fifteen year time span, from 1977-1992, mussels were collected at 378 stations. From these stations, 47 were chosen to conduct statistical analysis based on the criteria that they had been sampled at least 6 times for total DDTs, total polychlorinated biphenyls (PCBs), and total chlordanes. Declines of total DDTs and chlordanes were noted at approximately half of the stations. Declines of total PCBs were noted at approximately one-quarter of the stations. Declines of PCBs but not DDTs in mussels near Los Angeles County's sewer discharge corresponded to declines of these contaminants in treated effluent.

Animals↗
PubMed1995

Magnesium and calcium concentration in the pregnant and non-pregnant myometrium.

OBJECTIVES: To investigate the effect of labor on the magnesium and calcium concentrations in the human myometrium and to compare them with the concentrations in the non-pregnant uterus. METHOD: Samples of the isthmic part of the uterus were taken from 42 patients not in labor, 31 patients in regular labor during a cesarean section, and 37 premenopausal patients on whom a hysterectomy was performed. RESULTS: (i) The magnesium concentration dropped significantly during labor; (ii) the calcium concentration in the tissue showed no significant changes during labor; (iii) the magnesium and calcium concentrations were significantly higher during pregnancy; (iv) the distribution of electrolytes in the myometrium differed significantly in the corpus, isthmus and cervix uteri. CONCLUSIONS: The electrolyte concentration in the myometrium depends on the place of removal. A low magnesium concentration in the pregnant human myometrium could be a cause of premature labor.

Calcium↗
PubMed1995

Liver transplant after massive spontaneous hepatic rupture in pregnancy complicated by preeclampsia.

BACKGROUND: Spontaneous hepatic rupture associated with preeclampsia is a rare but life-threatening situation. Several different surgical treatments have been described, depending on the severity of the rupture. Liver transplantation has become the mainstay for patients with end-stage liver disease. Transplantation in the setting of liver trauma or massive parenchymal disruption is not well defined. To our knowledge, this treatment has not been reported for spontaneous hepatic rupture in pregnancy. CASE: Massive, spontaneous hepatic rupture occurred in a patient at 36 weeks' gestation as a result of severe preeclampsia. Conventional surgical therapies were unsuccessful in controlling the massive hemorrhage. As a life-saving measure, the patient underwent total hepatectomy with the creation of an end-to-side portcaval shunt, thereby rendering the patient anhepatic. The patient was listed as urgently needing a liver for transplantation through the United Network for Organ Sharing. A suitable donor liver was located approximately 8 hours after the emergency hepatectomy. The patient underwent orthotopic liver transplantation after being maintained in an anhepatic state for almost 13 hours. The patient was discharged on postoperative day 41, suffering only from some ischemic lower extremity neuropathy secondary to hypovolemic hypotension occurring during the hepatectomy procedure. CONCLUSION: In the reported case, spontaneous hepatic rupture resulted in a massive hemorrhage that could not be controlled by previously reported techniques and required total hepatectomy followed by liver transplantation.

Adult↗
PubMed1995

Danegeld remembered: taxing further the coin head illusion.

Two experiments studied memory for the appearance of a Danish 20 kroner coin. The coin bears the portrait of Queen Margrethe II in profile, facing to the right. Previous studies have examined memory for British coins, which similarly bear a right-facing portrait of Queen Elizabeth II. They have revealed the occurrence of a mnemonic illusion, in that British people tend to believe the portrait faces left. This finding has been attributed to the occurrence of a joint coin-stamp schema. British stamps bear a left-facing profile of the Queen, and it is possible that information from the stamp predominates in the formation of the schema. In the case of Denmark, however, stamps bear a full-face portrait of the Queen. Nevertheless, the present experiments showed that the Coin Head Illusion is also found in Denmark. That is, the number of participants recalling the Queen's head as facing to the right was significantly below even the chance level of 50%. Further, this result occurred both for residents of Denmark and for visitors to Denmark. These findings suggest that the bias underlying the Coin Head Illusion may be a more general one than that envisaged by the joint coin-stamp schema hypothesis.

Adult↗