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Biomedical subjects

M Marco

Publications and source records attributed to M Marco.

13 recordsLinked to original sources
PubMed1992

The application of microdosimetry in clinical bone densitometry using a dual-photon absorptiometer.

Experimental microdosimetric methods have been used to determine absorbed dose values for a scanning dual-photon absorptiometer. Absorbed doses within the scanned field have been obtained for three different scanning speeds. For the normal speed setting used clinically, measurements have also been carried out in a water-filled phantom in order to estimate typical patient entrance, exit and midline doses. The results agree well with values obtained using thermoluminescence dosimetry and support the claims of the manufacturers with regard to upper limits placed on patient dose levels. The microdosimetric method enables changes in radiation quality to be followed and comparisons to be made with other low-energy photon fields used in medical diagnosis.

Absorptiometry, Photon↗
PubMed1991

Metalloproteinases in the larvae of Echinococcus granulosus.

Proteolytic activity in hydatid cyst fluid, cyst membranes and protoscoleces of E. granulosus was analyzed by electrophoresis in gelatin-containing polyacrylamide gels, including characterization with a set of protease inhibitors. All contained metalloproteinases in the range 60-120 kDa, with neutral/alkaline pH optima. Major activity was observed in hydatid fluid and the membranes (five bands) with both exhibiting similar electrophoretic patterns. The samples prepared from protoscoleces shared only some of these bands.

Animals↗
PubMed1978

[Enzymatic ocular hypertension: a statistical study (author's transl)].

The authors have carried out a statistical study on two large groups of patients operated on for cataract and in whom the enzyme alph-chymotrypsin has been used, and the occurrence of ocular hypertension has been examined. One group, which contained 1,003 operations most of which were under the microscope using a firm closure technique, was compared with another group of 324 cases operated under the same conditions but without using the enzyme. In all cases the intraocular pressure was measured 24-48 hours after the operation. The rise in pressure, the rapidity of its development were studied together with its duration and the concentration of the enzyme. In addition these findings were compared with another group of 2,334 eyes operated on several years previously with standard techniques using a less hermetic wound suture, without a microscope, with alpha-chymotrypsin, but whose tensions were controlled from the third week. The results show conclusively that there is a greater frequency of the occurrence of raised intra-ocular pressure when the enzyme is used (40,3%) than when it is not used (25,3%). This ocular hypertension persists in all cases to the end of three weeks. The time of the appearance of the hypertension, the numbers affected and the duration of the intraocular pressure were not significantly meaningful in the statistical analysis.

Cataract Extraction↗
PubMed1976

Lung function changes in smokers with normal conventional spirometry.

The comparative ability to detect early abnormalities in smokers by commonly used lung function tests was studied. Sixty-five healthy male nonsmokers served as a reference group and provided standards for 1-sec forced expiratory volume, vital capacity, end-tidal spirometry, spirometric forced mid-and end-expiratory flows, single-breath diffusing capacity, static lung volumes (helium method), and single-breath N2 closing volume measurements, In the present series of 80 male smokers, the measurements of forced mid-expiratory flow and forced end-expiratory flow did not improve the ability of the more conventional indices, 1-sec forced expiratory volume and the ratio of 1-sec forced expiratory volume to vital capacity, to detect obstructive lung disease. In 71 smokers with normal 1-sec forced expiratory volume and ratio of 1-sec forced expiratory volume to vital capacity, the end-tidal spirometry, diffusing capacity, and residual volume indices revealed 14,20, and 21 per cent of abnormalities. respectively. The single-breath N2 closing volume test (Phase IV/vital capacity and slope of Phase III) detected the greatest number of subtle changes in lung function; this was abnormal in 32 per cent of smokers with normal conventional spirometry. In young or light smokers, Phase IV/vital capacity was more frequently increased than the slope of Phase III; an incerse trend was observed in older or heavier smokers. The single-breath N2 closing volume test also provided the greatest number of abnormal results when other indices were impaired in the same subjects.

Adult↗