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Biomedical subjects

M Magno

Publications and source records attributed to M Magno.

27 records · Page 2Linked to original sources
PubMed1976

Hemodynamic pulmonary edema in dogs with acute and chronic lymphatic ligation.

The effect of lymphatic ligation on relative lung water (g H2O/g dry lung) was studied in dogs. Raising left atrial pressure to 20 mmHg for 2 h in chronically lymphatic-ligated dogs (4 days) caused a significantly greater increase in relative lung water than the same hemodynamic challenge did in sham-operated and acutely lymphatic-ligated dogs. There was no significant difference in relative lung water between the acutely lymphatic-ligated and sham-operated dogs. At normal left atrial pressures, there was no significant difference in relative lung water between the sham-operated and chronically lymphatic-ligated dogs. Since the combined effects of chronic lymphatic ligation and left atrial hypertension is greater than the sum of the individual effects, it appears that chronic lymphatic ligation increases the susceptibility of the lung to hemodynamic edema, we suggest that chronic lymphatic ligation may have produced increases in the interstitial volume and protein mass that are undetectable by our technique. These increases, in turn, could lead to a reduction in tissue safety factors against hemodynamic pulmonary edema.

Animals↗
PubMedDate not supplied

Cardiomyoplasty. Latissimus dorsi muscle function and blood flow during isolation.

Cardiomyoplasty is a new surgical treatment for heart failure in which skeletal muscle assists the heart. However, for the first 2 weeks postoperatively, the latissimus dorsi muscle (LDM) remains unstimulated, and during the next 2 weeks, the LDM is stimulated with only one pulse every other heart beat. Thus, for the initial 4 postoperative weeks, minimal systolic assistance is provided. The present study determined if the LDM is capable of providing early assistance. Cardiomyoplasty surgery involves severing the perforating intercostal arteries to the LDM, detaching the LDM from its distal insertion, and wrapping it around the heart. At each of these steps, we measured LDM force development, shortening, and blood flow in six dogs. At control, LDM shortening, work, and power decreased during a 2 min fatigue test: fatigue indices (final/ initial value) for shortening, work, and power were 47.6 +/- 6.9%, 47.5 +/- 7.1%, and 46.9 +/- 6.6%, respectively. Blood flow increased in the proximal (P), mid (M), and distal (D) LDM during the fatigue test. After partial vascular isolation, initial shortening, work, and power decreased by 29.4%, 32.5%, and 31.7% from their respective control values. During the fatigue test, fatigue indices for shortening, work, and power were 24.7 +/- 3.3%, 19.5 +/- 4.6%, and 22.2 +/- 4.7%, respectively, all significantly (p < 0.05) less than control values. Resting blood flows were unaltered. During exercise, flow to the P increased, whereas flow did not increase in M (p < 0.05). Loss of LDM function was most apparent after mobilizing and reattaching the muscle. Initial shortening, work, and power significantly decreased (p < 0.05) by 74.1%, 76.8%, and 74.4%, from their respective control values. During a fatigue test, final values for shortening, work, and power were all near zero. Resting blood flow decreased in the M and D (p < 0.05) and, during exercise, blood flow increased only in P. Thus, LDM function was severely depressed during the isolation procedure. This functional loss is associated with inadequate blood flow responses. Therefore, preconditioning and/or revascularization is needed if the LDM is to provide cardiac assistance shortly after cardiomyoplasty surgery.

Animals↗
PubMedDate not supplied

Myofibroblast involvement in glycosaminoglycan synthesis and lipid retention during coronary repair.

Myofibroblasts of adventitial origin have been linked to neointimal formation and remodeling after coronary injury. Accordingly, the goal of this study was to examine whether myofibroblasts contribute to focal accumulation of glycosaminoglycans (GAGs) and lipids during coronary repair. GAG synthesis was assessed by ex vivo labeling of balloon-injured porcine coronary arteries with (14)C-glucosamine. The synthesis of total GAGs transiently increased at 8 days in the normolipemic model (a 2.2-fold increase over baseline, p < 0.05). The majority of newly synthesized GAGs were sensitive to chondroitin ABC lyase (chondroitin/dermatan sulfate GAGs). Versican was localized to myofibroblast-rich regions in the adventitia and neointima [positive for alpha-smooth muscle (SM) actin, negative for h-caldesmon and SM myosin heavy chain]. In contrast, the adjacent SM-rich media showed no increase in versican expression. The association between injury-induced GAG accumulation and lipid retention was examined at 2 weeks after coronary injury in the hyperlipemic model. Lipid (Oil Red O) accumulated in the neointima and adventitia, but not in the adjacent media. Coronary repair under hyperlipemic conditions was associated with macrophage infiltration (19 +/- 5 vs. 3 +/- 2% of neointimal cells in normolipemic animals, p < 0.001) and increased neointimal formation (1.8 +/- 0.5 vs. 1.0 +/- 0.3 mm(2) in normolipemic animals, p < 0.01). In conclusion, this study demonstrated a transient increase in GAG synthesis following coronary injury. Chondroitin sulfate proteoglycans (e.g., versican) were rapidly synthesized by activated adventitial and neointimal cells which could contribute to early lipid retention in injured vessels.

Animals↗
PubMedDate not supplied

Analysis of diabetic family connection in subjects with insulin-dependent diabetes mellitus (IDDM).

The family connection of diabetes was examined from the clinical records of 3,372 subjects who were seen, as an out patient population, within the frame of a Regional Health Program in Taranto, South Italy. The family connection of diabetes resulted from a questionnaire in which the subjects had to give informations about their disease, if present, and degrees of relationship that were directly verified by us with the examination (clinic and laboratory) of relatives said to have diabetes. From the analysis of records, it emerged that 112 patients were affected by insulin-dependent-diabetes mellitus (IDDM): 54 of them were related with at least one subject suffering from noninsulin-dependent diabetes mellitus (NIDDM), 13 with at least one subject affected by IDDM and the remaining 45 did not show any family connection. The corresponding figures found in a group of healthy control subjects, matched to IDDM patients for age, sex and BMI, were 19, 2 and 84, respectively (p less than 0.001). 34 IDDM patients were related with a first degree of relationship (parents, sons, sibs) to diabetic subjects (IDDM or NIDDM), but only 4 controls showed such a degree (p less than 0.001). These results seem to indicate that patients with IDDM have an increased family history of NIDDM.

Adolescent↗