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Biomedical subjects

M Martel

Publications and source records attributed to M Martel.

32 records · Page 2Linked to original sources
PubMed1986

Enzyme activities of lung lavage in asbestosis.

We analyzed lung lavage supernatant for amylase, lactate dehydrogenase (LD), alkaline phosphatase (ALP), beta-glucuronidase (beta G), and albumin, and a differential count was made of the cellular component of lung lavage in 18 normal controls and 36 long-term asbestos workers of the mines and mills of Québec. The men were concomitantly evaluated by the usual clinical, radiological, functional parameters and 67Ga lung scan. In 7 workers without asbestosis and normal 67Ga scan, lavage enzyme activities, albumin and cell counts were comparable to those of controls. Of 9 without sufficient criteria for asbestosis but increased 67Ga lung uptake, cell counts documented significant increases in the mean number of macrophages (X 2), lymphocytes (X 2) and neutrophils (X 3). Supernatant analyses showed significant increases in amylase (X 4-5), LD (X 2.5), ALP (X 1.5) and beta G (X 2-4). These changes were comparable to those in the lavage of workers with well established asbestosis except that in the latter, the lymphocyte count was slightly lower but the neutrophil count higher (p less than 0.05). These data document that enzyme activities of lung lavage can differentiate asbestos workers with early or late asbestosis from controls and asbestos workers without disease.

Adult↗
PubMed1986

Fibronectin and procollagen 3 levels in bronchoalveolar lavage of asbestos-exposed human subjects and sheep.

To evaluate the potential interest of levels of fibronectin and procollagen 3 in bronchoalveolar lavage fluid as markers of fibrogenic activity, we characterized the time course of changes in fibronectin and procollagen 3 levels in the tracheal lobe of sheep exposed to nonfibrogenic and fibrogenic materials. We correlated these observations with those of bronchoalveolar lavage in long-term asbestos workers in various stages of disease activity. Following studies before exposure, the tracheal lobe of three groups of 24 sheep were exposed once to 100 ml of phosphate-buffered saline solution (PBS), to 100 mg of latex beads in 100 ml of PBS, or to 100 mg of chrysotile fibers in 100 ml of PBS. Bronchoalveolar lavages were obtained at 0, 1, 2, 4, 8, and 12 months after exposure, and four or five sheep per group were killed after each lavage for histopathologic analysis. Fibronectin in bronchoalveolar lavage fluid increased significantly only in the asbestos-exposed sheep to values two to three times above controls or latex-exposed sheep and remained elevated during the 12 months of the study. Levels of procollagen 3 in bronchoalveolar lavage fluid were increased significantly only during the first two months following exposure in the asbestos-exposed sheep only. In the asbestos workers without disease, levels of fibronectin and procollagen 3 in bronchoalveolar lavage fluid were comparable to controls, but these levels were significantly elevated in those with asbestos-associated alveolitis or asbestosis. This study documents that the measurement of levels of fibronectin and procollagen 3 in bronchoalveolar lavage fluid assesses fibrogenic activity of alveolitis and should be useful to predict its progression in a fibrotic process. In asbestos workers the potential use of these markers is primarily related to early detection of asbestos-induced pulmonary injury.

Adult↗
PubMed1986

Aluminum lactate treatment alters the lung biological activity of quartz.

Previous studies of surface modification of quartz particles have suggested that the biological activity of silica is at least in part related to its surface properties. In the present study, we exposed the tracheal lobe of 8 sheep to either 100 ml saline (saline group), 100 mg of quartz (Minusil-5) in 100 ml saline (SI group) or 100 mg of Al lactate treated quartz in 100 ml saline (SI-Al group). The 24 sheep were studied by bronchoalveolar lavage at days 0, 12, 24, 40, 60 and by autopsy at day 60. In the saline group, BAL analyses were as previously reported [1]. In the SI group, we found significant and sustained increases in total BAL cells (x 2, P less than 0.05), macrophages and lymphocytes (x 2, P less than 0.05), neutrophils (x 5-10, P less than 0.01), IgG (x 1.2-1.8, P less than 0.05), fibronectin (x 2-3, P less than 0.05), lactate dehydrogenase (x 3, P less than 0.01) and alkaline phosphatase (x 2, P less than 0.05). Histologically, a macrophagic and lymphocytic alveolitis was observed at day 60. In the SI-Al group, these changes were significantly attenuated and in the above parameters, SI-Al group did not differ from saline group after day 24. These data of BAL and histology of the sheep tracheal lobe model document clearly that aluminum lactate treatment alters the biological activity of quartz.

Animals↗
PubMed1986

Adaptation of enzymes to temperature: myofibrillar adenosine triphosphatase from two terrestrial isopod species.

A comparison of the temperature profiles of the myofibrillar ATPase in Porcellio spinicornis and Metoponorthus pruinosus showed that Porcellio enzyme had a maximum activity between pH 6.8-7.2 at 9 degrees C, and that from Metoponorthus between pH 7.0-7.4 at 45 degrees C. The energy of activation for Porcellio enzyme was estimated to be 2.964 kcal/mol and that for Metoponorthus enzyme 9.91 X 10(-1) kcal/mol. The significance of these findings in relation to the natural habitats of these two species is discussed.

Adaptation, Physiological↗
PubMed1986

Gallium-67 uptake in the lung of asbestos exposed sheep: early association with enhanced macrophage-derived fibronectin accumulation.

To evaluate the time course and mechanisms of enhanced 67Ga lung uptake in asbestosis, we exposed two groups of sheep every 2 wk to either 100 ml saline (controls) or 100 mg UICC chrysotile fibers in 100 ml saline. The sheep were evaluated periodically by pulmonary function tests (PFT), thoracic radiograph (TR), 67Ga lung scan bronchoalveolar lavage (BAL), and transbronchial lung biopsy (TLB). By month 24 of the study, 9/15 exposed sheep had developed the initial alveolitis and had significant changes in PFT, TR, and TLB. The other six exposed sheep differed from controls only by a 75% increase in BAL fibronectin until month 30, where significant changes in albumin occurred and 67Ga scan score increased. The nine sheep with alveolitis had significant sustained increases in 67Ga scan and BAL levels from month 6, associated with a 150% increase in BAL fibronectin and other parameters of disease activity changed from month 18 to 30. We concluded that in the sheep model of asbestosis, significant changes in 67Ga scan, 67Ga BAL counts, and excessive elevation of BAL fibronectin preceded other parameters of disease activity. The data suggest that excessively activated macrophages are primarily responsible for the early 67Ga lung uptake.

Animals↗
PubMed1985

Identification of proximal tubule segments in the mouse nephron by simultaneous visualization of alkaline phosphatase and gamma-glutamyl transpeptidase.

ALP and gamma-GT are 2 brush border enzymes that can be individually demonstrated on adjacent sections by the histochemical methods of Mayahara (ALP) and Rutenberg (gamma-GT). On the basis of each enzyme activity, it was possible to recognize different categories of tubules in the mouse nephron. In fact, both enzymes were heterogeneously distributed along the proximal tubule, but in opposite gradients. The various staining intensities probably corresponded to proximal segmentation, but were sometimes difficult to evaluate. A technique was perfected to localize both enzymes in the same tissue section. Since each enzyme produced a distinct type of colored precipitates (ALP: black, gamma-GT: red), 4 categories of tubules could be identified, according to staining characteristics: 1. black tubules where ALP activity was predominant, corresponded to S1 segments, 2. black and red tubules where the 2 activities were about equivalent, were considered as parts of S2, 3. red ones where gamma-GT activity was high, were identified as portions of S3, 4. negative tubules where no activity was apparent, represented distal and straight collecting tubules. In addition to economize time and tissue, this simple technique permits to easily estimate variations in enzyme activities that probably correspond to structural and functional differences in the segments of the proximal tubule.

Alkaline Phosphatase↗
PubMed1984

Heterogeneous distribution of alkaline phosphatase and gamma-glutamyl transpeptidase in the mouse nephron.

In the mouse nephron, ALP and gamma-GT were found to be heterogeneously distributed along the proximal tubule. For both enzymes, 4 large categories of tubules could be recognized on the basis of the enzymatic activity: intense; intermediate; weak; negative. The localization of ALP and gamma-GT was in opposite gradient along the proximal tubule and it apparently corresponded to the 3 sequential segments S1, S2, and S3. In fact, S1 could be identified with certainty because this first portion was often seen attached to the renal corpuscle. This segment displayed a very intense ALP activity (category 1), but a weak one for gamma-GT (category 3). Intermediate tubules for ALP and gamma-GT activities (category 2) seemingly were parts of S2. Those tubules where ALP activity was weak (category 3) while that of gamma-GT was intense (category 1) probably belonged to S3. As a result, it becomes possible to clearly distinguish the segments S1, S2, and S3, not only on a structural and biochemical basis but as well by the localization of brush border enzymes. Distal tubules showed no enzyme activity (category 4). In other respects, the presence of ALP and gamma-GT on the parietal layer of Bowman's capsule strongly suggests that these tall cylindrical cells are morphologically and enzymatically identical to those of the S1 segment, and that they might have similar functional roles.

Alkaline Phosphatase↗
PubMed1984

Simultaneous visualization of alkaline phosphatase and gamma-glutamyl transpeptidase in kidney sections.

An histochemical method is presented to simultaneously localize, for the first time, alkaline phosphatase (ALP) and gamma-glutamyltranspeptidase (gamma-GT) in the kidney. The reaction product of ALP activity appears as a dark brown precipitate of lead sulfide, while a bright red copper chelate of an azo dye (Fast blue BBN salt) final product indicates sites of gamma-GT activity. The amalgamation of Mayahara's (ALP) and Rutenberg's (gamma-GT) techniques resulted in the demonstration of various categories of kidney tubules, according to the staining reaction of the cell brush borders: Black tubules where ALP predominates; Intermediate tubules showing a mixture of brown and red precipitates; Red tubules indicating a prevalence of gamma-GT activity; Negative tubules. A possible relation might exist between the staining characteristics observed and the different proximal tubule segments, thus allowing their distinction. In addition, this technique has the advantage to permit the concomitant study of ALP and gamma-GT distribution on the same tissue section instead of serial sections, so reducing the number of manipulations and observations as well as the amount of tissue required.

Alkaline Phosphatase↗
PubMed1975

Mechanism of action of Mg2+ and Zn2+ on rat placental alkaline phosphatase. I. Studies on the soluble Zn2+ and Mg2+ alkaline phosphatases.

Rat placental alkaline phosphatase (EC 3.1.3.1), a dimer of 135,000 daltons, is strongly activated by Mg2+. However, Zn2+ has to be present on the apoenzyme to obtain this activation. Mg2+ alone is unable to reconstitute functional active sites. Excess Zn2+ which competes for the Mg2+ site leads to a phosphatase with little catalytic activity at alkaline pH but with normal active sites at acidic pH as shown by covalent incorporation of ortho-[32P]phosphate. Two enzyme species with identical functional active sites have been reconstituted that only differ by the presence of Zn2+ or Mg2+ at the effector site. A mechanism is presented by which alkaline phosphatase activity of rat placenta would be controlled by a molecular process involving the interaction of Mg2+ and Zn2+ with the dimeric enzyme molecule.

Alkaline Phosphatase↗
PubMedDate not supplied

Determination of the relative angle between orthogonal films for radioactive implants.

Dose calculations for radioactive seed implants require knowledge of the three-dimensional source coordinates. These are usually determined from a pair of orthogonal radiographs. However, occasionally localization films are taken with portable, and/or nonisocentric x-ray units, and no assurances can be made as to whether or not the films were truly exposed in an orthogonal geometry. A three-dimensional magnification ring is described (consisting of three mutually orthogonal rings) which permits the treatment planner to accurately establish the exact source rotation angle used when exposing the films. This angle can in turn be used when reconstructing source coordinates, to insure accuracy in treatment planning.

Algorithms↗