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Biomedical subjects

M Martin

Publications and source records attributed to M Martin.

At least 307 records · Page 17Linked to original sources
PubMed1997

[Pulmonary alveolar proteinosis: ultrastructural study of 4 cases].

Pulmonary Alveolar Proteinosis (PAP) is a rare and diffuse lung disease characterized by the abnormal deposition of PAS positive, lipoproteinaceous material in the alveolar spaces. It has been related, mainly, to alterations in the immune state and to secondary infections. We studied four cases of PAP diagnosed by light microscopy. In two cases we were able to demonstrate disseminated Histoplasmosis related to immunodeficiency states (AIDS and malnutrition), one case with Pneumocystis carinii infection and AIDS, and one case with no related pathology. Granular and electron dense material, concentric myelin figures, and variable-sized osmiophilic bodies were observed by electron microscopy. We found yeast-like structures, trophozoites and cysts in the alveolar spaces, in the Histoplasmosis and Pneumocystic carinii infection cases, respectively. In one of our cases, the circulating neutrophils showed crystalloid inclusions in the nucleus. PAP should be considered in the differential diagnoses of patients with pulmonary infiltrates.

Adult↗
PubMed1997

Analysis of carbon metabolism in cultured cerebellar and cortical astrocytes.

Carbon metabolism was investigated in cerebellar and cortical astrocytes cultured for 15 or 35 days. The consumption rates of exogenous carbon sources--amino acids and glucose--and the production rates of exported metabolites--citrate, lactate, alanine and glutamine--were determined. The specific 13C-enrichment of lactate and glutamine carbons were determined after cell incubation with [1-13C]glucose. These data were used to evaluate the fluxes through metabolic pathways using a monocompartmental model of the cell metabolism including glycolysis and tricarboxylic acid cycle related pathways. The model concluded to a very large contribution of fatty acids as an endogenous carbon source of acetyl-CoA. As a consequence of the high fatty acid turn-over, there was an important recycling (via pyruvate) of the oxaloacetate molecules generated by citrate lyase activity. This recycling represented in fact the major part of the pyruvate carboxylase activity, which therefore was not directly related to metabolite export. Comparing the data from cerebellar and cortical astrocytes evidenced, on the other hand, some differences in metabolite contents which could be related to different cell maturation stages linked to their different tissular origins.

Animals↗
PubMed1997

Preliminary results. UFT/methotrexate/leucovorin for breast Ca patients in progression after HDCT/PBPC support.

Twenty-four patients with metastatic breast cancer that had progressed after high-dose chemotherapy with peripheral blood progenitor cell (PBPC) support were given intramuscular methotrexate in combination with oral UFT (tegafur and uracil) and oral leucovorin (the MUL regimen). Of the total treated, 21 patients are currently evaluable for response and toxicity. All patients had received extensive prior chemotherapy, including a high-dose regimen with PBPC support. Of the 21 assessable patients, 8 obtained either a complete response (1) or partial response (7), for an overall objective response rate of 38%. Another 7 patients had stable disease for 3 or more months. Therefore, the MUL regimen was able to stop disease progression for 3 or more months in nearly 75% of patients. The median time to progression and median overall survival from the start of MUL were 6 and 9 months, respectively. The toxicity was mainly gastrointestinal; 6 patients (29%) had World Health Organization grade 2/3 diarrhea, leading to a UFT dose reduction. Emesis was mild and easily manageable with thiethylperazine. In conclusion, MUL chemotherapy is active and well tolerated in patients with metastatic breast cancer in progression after high-dose chemotherapy. Further studies with this regimen, either as salvage chemotherapy or as maintenance chemotherapy after high-dose chemotherapy with PBPC, are warranted.

Adult↗
PubMed1997

Paclitaxel plus doxorubicin in metastatic breast cancer: preliminary analysis of cardiotoxicity.

This ongoing phase II trial was designed to determine the antitumor activity and cardiotoxicity of a combination of doxorubicin (50 mg/m2) and paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) (175 to 225 mg/m2 over 3 hours) as first-line chemotherapy for metastatic breast cancer. Of 76 patients entered so far, 57 who had received at least three courses of chemotherapy are assessable for efficacy and cardiac toxicity. A slight majority (57%) of the patients entered had prior adjuvant chemotherapy, including 33% with anthracycline-containing combinations. An objective response was achieved by 70% of patients, with 18% complete responders. The main noncardiac toxicities were alopecia, neutropenia, mucositis, and peripheral neuropathy. Overall, after a median cumulative doxorubicin dose of 350 mg/m2, the evolution of left ventricular ejection fraction (LVEF) values did not significantly decrease from baseline to the sixth course of therapy. However, LVEF values decreased significantly in eight patients (14%). The LVEF decreased by more than 14% over basal values in three patients, although the final determination was still above the lower limits of normal. The remaining five patients had LVEF decreases that fell below the lower limits of normal (33% to 48%). None of the patients developed clinically evident heart failure. Our results indicate that the combination of doxorubicin (50 mg/m2) plus paclitaxel (175 to 225 mg/m2) is effective and does not induce a clinically relevant cardiotoxicity.

Adolescent↗
PubMed1997

Review of a home-based palliative care program for children with malignant and non-malignant diseases.

This retrospective chart review presents the patient characteristics and utilization of the home-based palliative care program at The Hospital for Sick Children in Toronto. A total of 126 children dying from a broad spectrum of diseases was admitted during the period 1986-1994, referred from neurosurgery, genetic/metabolic, neurology, neonatology, nephrology, cardiology, general pediatrics, general surgery, and pulmonology. At the time of review, 15 patients remained alive and 18 had been discharged from the program. Mean age at the time of referral was 4.8 +/- 0.51 years and mean age at death was 5.3 +/- 0.55 years. The mean number of days in hospital was 26.5 +/- 14.6 while days spent at home averaged 98.4 +/- 15.2; thus 80% of the children's remaining time was spent at home. The average number of parent-team contacts was 3.5 +/- 0.9 by pager and 24.0 +/- 2.9 by telephone. Of the 93 patients who died in the program, 53% died at home, 18% died in community hospitals, and 29% died in a tertiary care facility. Analgesic medications were administered to 54% of the patients; 56% of these then required opioid analgesia for pain and symptom management. Home-based palliative care appeared to be an effective program for many children with a variety of terminal illnesses after adequate supports for the child and family had been established.

Adolescent↗
PubMed1997

Aotearoa, New Zealand and the Centre for Human Care.

Aotearoa, New Zealand, is a small South Pacific nation in which the concept of the Centre for Human Care has been shared and explored through the writings and visits of Professor Jean Watson. This article expresses this experience personally and makes comments about the value universally of such a concept and vision.

Humans↗
PubMed1996

Quebec employs user-pay philosophy in launching drug-insurance plan.

The Quebec government has introduced a new provincial drug-insurance scheme that by January 1997 will provide coverage to all Quebecers. The first phase of the measure, which was instituted for reasons that were partly financial and partly social, came into effect in August, to the chagrin of the province's welfare recipients and elderly. They are the first to pay 25% of the cost of prescriptions under the new copayment plan.

Aged↗
PubMed1996

Circadian variation of tacrolimus disposition in liver allograft recipients.

The aim of this study was to characterize the circadian variation of oral tacrolimus disposition in 8 stable liver allograft recipients. In the steady state, a total of 23 blood samples was taken before and after tacrolimus administration during a 24-hr period and the pharmacokinetic parameters were compared. The area under the curve (AUC) of tacrolimus after the morning dose was significantly larger than after the evening dose (211+/-43 ng x hr/ml [morning] vs. 179+/-45 ng x hr/ml [evening], P=0.02). The time to peak (Tmax) was significantly shorter after the morning dose than after the evening dose (1.6+/-0.7 hr [morning] vs. 2.9+/-0.6 hr [evening], P=0.002). The peak (Cmax) was significantly higher after the morning dose than after the evening dose (32.2+/-10.2 ng/ml [morning] vs. 19.1+/-4.3 ng/ml [evening], P=0.003). However, the trough (Cmin) was not significantly different between the morning dose and the evening dose (13.1+/-3.9 ng/ml [morning] vs. 13.3+/-4.4 ng/ml [evening], P=0.4). This study demonstrated that tacrolimus disposition in liver transplant patients was determined by administration time.

Adult↗
PubMed1996

Mathematical modelling of the citric acid cycle for the analysis of glutamine isotopomers from cerebellar astrocytes incubated with [1(-13)C]glucose.

A mathematical model of the citric acid cycle devoted to the analysis of 13C-NMR data was developed for determining the relative flux of molecules through the anaplerotic versus oxidative pathways and the relative pyruvate carboxylase versus pyruvate dehydrogenase activities. Different variants of the model were considered depending on the reversibility of the conversion of fumarate into malate and oxaloacetate. The model also included the possibility of orientation-conserved transfer of the four-carbon citric acid cycle intermediates, leading to conversion of succinyl-CoA C1 into either malate C1 or C4. It was used to analyse NMR data from glutamine isotopomers produced by cerebellar astrocytes incubated with [1-13C]glucose. Partial cycling (39%) between oxaloacetate and fumarate was evident from the analysis. Application of the model to glutamate isotopomers from granule cells incubated with [1-13C]glucose [Martin, M.. Portais, J.C.. Labouesse. J., Canioni. P, & Merle, M. (1993) Eur. J. Biochem. 217, 617-625] indicated that total cycling of oxaloacetate into fumarate was, in this case, required to get the best fit. The results emphasized some important differences in carbon metabolism between cerebellar astrocytes and granule cells concerning the sources of carbon fuelling the citric acid cycle and the carbon fluxes on different pathways.

Acetates↗
PubMed1996

Group for antiwar MDs broadens focus, hopes to attract new members.

Physicians for Global Survival (Canada), formerly known as Canadian Physicians for the Prevention of Nuclear War, has changed its name and broadened its mission in an effort to increase membership. The group's international interests include banning antipersonnel land mines and having the threat or use of nuclear weapons declared illegal. In Canada, it has supported gun-control legislation and been involved in assessing the effect of military training flights on the Innu of Labrador. The president-elect Dr. Konia Trouton of the University of Calgary, says the association is the "ethical voice of the medical profession in its concern for social justice."

Canada↗
PubMed1996

The contributions of aspartyl residues in the acetylcholine receptor gamma and delta subunits to the binding of agonists and competitive antagonists.

The acetylcholine (ACh) receptors in muscle have the composition alpha2betagammadelta and contain two ACh binding sites. One is formed between an alpha subunit and the gamma subunit, and the other is formed between an alpha subunit and the delta subunit. Among the residues in the ACh binding sites are alphaCys-192 and alphaCys-193. The negatively charged deltaAsp-180 is at an appropriate distance from alphaCys-192/193 also to be in the ACh binding site and to interact electrostatically with the positively charged ammonium group common to agonists and competitive antagonists. Mutation to Asn of either deltaAsp-180 or the aligned residue in the gamma subunit, gammaAsp-174, decreased the affinities of three agonists, acetylcholine, tetramethylammonium, and succinyldicholine 170-560-fold. By contrast, these mutations decreased the affinities of three competitive antagonists, (+)-tubocurarine, hexamethonium, and dihydro-beta-erythroidine, only 2-15-fold. Agonists, but not antagonists, promote the transitions of the receptor from the resting state to the higher affinity active and desensitized states, and the greater effects of the mutations of gammaAsp-174 and deltaAsp-180 on the apparent affinities of agonists could reflect the involvement of these residues in the conformational changes of the receptor corresponding to its transitions to higher affinity states. In these transitions, one possibility is that gammaAsp-174 and deltaAsp-180 move closer to bound agonist.

Amino Acid Sequence↗
PubMed1996

Successful treatment of radiation-induced fibrosis using Cu/Zn-SOD and Mn-SOD: an experimental study.

PURPOSE: To establish how far liposomal copper/zinc superoxide dismutase (Cu/Zn-SOD) and manganese superoxide dismutase (Mn-SOD), respectively, reduce radiation-induced fibrosis (RIF), using a well-characterized pig model of RIF permitting the design of a controlled laboratory experiment. METHODS AND MATERIALS: In this model of acute localized gamma irradiation simulating accidental overexposure in humans, three groups of five large white pigs were irradiated using a collimated 192Ir source to deliver a single dose of 160 Gy onto the skin surface (100%) of the outer side of the thigh. A well-defined block of subcutaneous fibrosis involving skin and skeletal muscle developed 6 months after irradiation. One experimental group of five pigs was then injected i.m. with 10 mg/10 kg b.wt. of Cu/Zn-SOD, twice a week for 3 weeks, and another experimental group of five was injected with 10 mg/10 kg b.wt. of Mn-SOD, three times a week for 3 weeks. Five irradiated control pigs were injected with physiological serum. Animals were assessed for changes in the density of the palpated fibrotic block and in the dimensions of the projected cutaneous surface. Block depth was determined by ultrasound. Physical and sonographic findings were confirmed by autopsy 12-14 weeks after completing SOD injections. The density, length, width, and depth of the fibrotic block, and the areas and volume of its projected cutaneous surface were compared before treatment, 1, 3, and 6 weeks thereafter, and at autopsy, 12-14 weeks after treatment ended. RESULTS: The experimental animals exhibited no change in behavior and no abnormal clinical or anatomic signs. Whether they were given Cu/Zn- or Mn-SOD, significant and roughly equivalent softening and shrinking of the fibrotic block were noted in all treated animals between the first week after treatment ended and autopsy, when mean regression was 45% for length and width, 30% for depth, and 70% for area and volume. Histologic examination showed completely normal muscle and subcutaneous tissue surrounding the residual scar. This replacement of scar tissue by normal tissue in experimental animals and the 50% decrease in the linear dimensions of the scar were comparable to the results obtained in previous clinical studies and highly significant compared to the clinical and autopsy results for the control animals. CONCLUSIONS: Our results are striking and comparable to the results obtained in our previous clinical study after liposomal Cu/Zn-SOD treatment. To our knowledge, this is the first time that two agents have been shown to reverse the radiation-induced fibrotic process in experimental animals and to permit the regeneration of normal tissue in a zone of well-established postirradiation fibrosis.

Animals↗
PubMed1996

Lower serum transcortin (CBG) in major depressed females: relationships with baseline and postdexamethasone cortisol values.

This study has been carried out to examine (i) transcortin or corticosteroid binding globulin (CBG), the major glucocorticoid transport protein, in major depressed versus minor depressed and normal subjects; and (ii) the relationships between CBG and basal and postdexamethasone cortisol or adrenocorticotropic hormone (ACTH) values. Serum CBG was significantly lower in major depressed than in minor depressed subjects and normal controls. The significant decrease in serum CBG was observed in major depressed women but not in major depressed men. In depressed subjects, there was a significant and negative relationship between serum CBG and severity of illness. There were significant positive relationships between serum CBG and basal 8:00 a.m. plasma cortisol in normal volunteers (r = 0.87, P < 10(-4)) and depressed subjects (r = 0.40, P = 0.0002). There was no significant relationship between serum CBG and 24-h urinary cortisol. In depressed patients, there was a positive relationship between serum CBG and postdexamethasone cortisol (r = 0.31, P = 0.003). It is concluded that, in depression, serum CBG levels should be taken into consideration for the interpretation of baseline and postdexamethasone plasma total cortisol levels.

Adjustment Disorders↗
PubMed1996

[Ex vivo increase in hematopoietic progenitor cells for clinical use].

BACKGROUND: The clinical use of ex vivo expanded hematopoietic progenitor cells is currently explored. MATERIAL AND METHODS: In this study the culturing of G-CSF mobilized and purified CD34+ blood cells was investigated. The interleukins IL-1 beta, IL-3 and IL-6 (each at a dose of 300 U/ml) and stem cell factor (25 ng/ml) without or with erythropoietin (1 U/ml) were used. Cells of 10 healthy sibling donors and 10 patients with solid tumors were incubated under small-scale (n = 15, 2 ml) and large-scale (n = 7, 50 ml) culture conditions at 37 degrees C for 5 and 4 weeks, respectively. The cell density was adjusted to about 1 x 10(5) cells/ml. RESULTS: The nucleated cell counts increased approximately 7-fold and 10- to 70-fold after 1 and 2 weeks of incubation. Numbers of CD34+ cells doubled to triplicated within this time interval, without any significant changes in their clonogenicity (CFU-GM and BFU-E output). Thereafter a depletion of the CD34+ cell pool was noticed. However the numbers of CD34+/CD38(-)- or CD34+/ HLA-DR(-)- cells were reduced to a lesser extent. The expanded cells generated predominantly myeloid and almost no lymphoid cells. More glycophorin-A+ cells were produced when erythropoietin was added. Replacement of non-human additives with heat-inactivated autologous plasma had no influence on cell growth. Almost no proliferation was obtained with a 10-fold higher cell density (1.7 x 10(6)/ml in 100 ml), but the cells maintained their viability for 13 to 16 days. CONCLUSIONS: This study suggests, that the chosen culture conditions might be feasible for a large-scale ex vivo expansion of hematopoietic progenitor cells for clinical application. The impact of the ex vivo generated cells on hematopoietic regeneration after chemotherapy is currently under clinical investigation.

Antigens, CD34↗
PubMed1996

Colon-cancer cell variants producing regressive tumors in syngeneic rats, unlike variants yielding progressive tumors, attach to interstitial collagens through integrin alpha2beta1.

Nine clones of tumor cells, derived from a single rat colon carcinoma, were analyzed for their adhesive properties and in vivo growth patterns. Four clones (denoted REG) gave rise to regressively growing tumors. Cells from the 4 REG clones attached significantly better to collagen types I and III than did cells from the 5 clones (denoted PRO) which grew progressively in vivo. In contrast, REG and PRO clones did not differ in their attachment to collagen type IV, laminin or fibronectin. The attachment of REG cells to collagen was dependent on Mg2+, but not Ca2+. Monospecific rabbit IgG to rat integrin beta 1-chain inhibited REG cell attachment to collagen, demonstrating involvement of a beta 1 integrin in this process. PRO and REG cells expressed an underglycosylated beta 1 chain (Mr approximately 105,000) that was somewhat smaller than beta 1-chains described previously on rat fibroblasts and hepatocytes (Mr approximately 115,000). Monoclonal IgG to rat integrin alpha 2 beta 1, but not to alpha 1 beta 1, readily inhibited REG cell attachment to collagen, demonstrating the involvement of integrin alpha 2 beta 1. However, beta 1 and alpha 2 integrin subunits were found in purified glycoproteins from both PRO and REG cells. This suggests that alpha 2 beta 1 integrin is expressed by both cell variants, but is functional as a collagen receptor on REG cells only. In this system of tumor-cell variants, the clear-cut differences in attachment to interstitial collagens of the 9 clones suggest a possible relationship between this attachment and the capacity to induce progressive or regressive tumors.

Amino Acid Sequence↗
PubMed1996

As number of patients grows, so do critical problems facing MDs who provide dialysis.

The growth in the number of dialysis patients in Canada is causing a critical shortage of resources. The low transplantation rate and an increase in the number of patients, combined with insufficient funding to expand facilities, threatens access to the expensive but life-sustaining therapy. Michel Martin, who recently underwent a kidney transplant, looks at the situation facing dialysis patients in Quebec and Ontario.

Cost of Illness↗