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Biomedical subjects

R Noel

Publications and source records attributed to R Noel.

16 recordsLinked to original sources
PubMed2001

Biomechanical hearts: muscular blood pumps, performed in a 1-step operation, and trained under support of clenbuterol.

BACKGROUND: As shown previously in goats, clenbuterol increased the power of electrically conditioned skeletal muscle ventricles (SMVs) of clinically relevant size (150 mL), which were constructed around a mock system. They pumped against a pressure of 60 to 70 mm Hg immediately during surgery and up to several months after, finally at >1 L/min. SMVs without clenbuterol administration failed. Thus, we expected that clenbuterol-supported SMVs might become integrated into the circulation by a 1-step operation instead of the 2-step procedure required up to now. METHODS AND RESULTS: In adult Boer goats (n=5), latissimus dorsi muscle was wrapped around a polyurethane chamber of 150 mL that was connected to the descending aorta. This muscular flow-through pumping chamber containing a stabilizing inner layer (called a biomechanical heart [BMH]) was formed and immediately made to work against a systemic load with the support of clenbuterol (5x150 microg/wk). During surgery, the mean stroke volume of BMHs was 53.8+/-22.4 mL. One month after surgery, in peripheral arterial pressure, the mean diastolic (P(MD)) and minimal diastolic (P(min)) pressures of BMH-supported heart cycles differed significantly from unsupported ones (P(MD)=+2.9+/-1.1 mm Hg [P<0.04], P(min)=-2.4+/-0.9 mm Hg [P<0.04]). After BMH-supported heart contractions, the subsequent maximal rate of pressure generation, dP/dt(max), increased by 20.5+/-8.1% (P<0.02). One BMH, catheterized 132 days after surgery, shifted a volume of 34.8 mL per beat and 1.4 L/min with a latissimus dorsi muscle of 330 g. Depending on duration of training, the percentage of myosin heavy chain type 1 ranged between 31% and 100%. CONCLUSIONS: Under support of clenbuterol, BMHs of a clinically relevant size can be trained effectively in the systemic circulation after a 1-step operation and offer the prospect of a sufficient volume shift and probably unloading of the left ventricle.

Animals↗
PubMed2000

Clenbuterol-supported dynamic training of skeletal muscle ventricles against systemic load: a key for powerful circulatory assist?

BACKGROUND: The profound loss of power that occurs in skeletal muscle after electrical conditioning has been the major limiting factor in its clinical application. This study investigates a 3-fold approach for chronic conditioning of skeletal muscle ventricles (SMVs) combining electrical transformation, dynamic training against systemic load, and pharmacological support with clenbuterol. METHODS AND RESULTS: In 10 adult male goats, SMVs were constructed from latissimus dorsi muscle wrapped around an intrathoracic training device with windkessel characteristics. SMVs were stimulated electrically and trained dynamically by shifting volume against systemic load. Group 1 goats were controls (n=5), and group 2 goats (n=5) were supported with clenbuterol (150 microg 3 times a week). SMV dynamics were recorded weekly over 5 to 8 months: peak pressure (P(max)), stroke volume (SV), volume displacement per minute (VD), stroke work per day (SW/d), and maximum rates of pressure generation, +dP/dt(max), and decay, -dP/dt(max). In group 1, after 149.5+/-2.7 days (n=4), data were P(max)=70.8+/-4.7 mm Hg, SV=3.2+/-1.2 mL, VD=62.3+/-21.1 mL/min, SW/d=0.8+/-0.4 kJ, +dP/dt(max)=64+/-13 mm Hg/s, and -dP/dt(max)=156+/-32 mm Hg/s. These parameters were significantly improved (P<0.007) in the clenbuterol-treated group 2 after 151+/-2.7 days: P(max)=176.2+/-43.8 mm Hg, SV=23.3+/-6.1 mL, VD=568.2+/-186.1 mL/min, SW/d=9.1+/-2.2 kJ, +dP/dt(max)=1134+/-267 mm Hg/s, and -dP/dt(max)=1028+/-92 mm Hg/s. In 2 SMVs of group 2, VD increased to 1090 and 1235 mL/min after 202 and 246 days of training, respectively. At termination, myosin heavy chains were totally transformed into myosin heavy chain-1 in all SMVs. CONCLUSIONS: This clenbuterol-supported dynamic training provides powerful SMVs that may have important clinical implications for the treatment of end-stage heart failure by muscular blood pumps.

Animals↗
PubMed1997

New method for monitoring the functional state of a dynamic cardiomyoplasty.

OBJECTIVE: To assess the impact of a dynamic cardiomyoplasty on failing hearts, it is essential to estimate the contraction force of the skeletal muscle and how its contraction is synchronized with the heart cycle. METHODS: In a 6-month study a small fluid-filled, balloon-mounted catheter was placed between the myocardium and the muscular wrap in five adult female Boor goats and two female domestic pigs. The catheter was connected to a subcutaneous measuring chamber whereby pressure monitoring could be accomplished. Distinct pressure signals as a result of function of the dynamic cardiomyoplasty and the heart were detected initially in all animals. RESULTS: Maximal relative pressure from the dynamic cardiomyoplasty was calculated as 336.2% +/- 69.4% on day 24 +/- 6.1 (n = 7) and end-stage pressure as 59.8% +/- 9.7% on day 174.6 +/- 13.1 (n = 4). A functional loss of pressure signals from the dynamic cardiomyoplasty was correlated to severe histologic muscle damage (n = 3). Pressure signals transferred from the contracting myocardium to the catheter showed defined segments of contraction, ejection, and filling periods, allowing a mechanical synchronization of the dynamic cardiomyoplasty to the heart cycle. CONCLUSIONS: This monitoring catheter enabled the assessment of the functional state of the dynamic cardiomyoplasty and allowed a synchronization to the heart cycle. It will promote understanding and might help to avoid muscle damage in dynamic cardiomyoplasty for an improved outcome of the surgical treatment of end-stage heart failure.

Animals↗
PubMed1996

A parastomal hernia causing small-bowel obstruction.

A parastomal hernia is an incisional hernia that occurs at the site of an intestinal stoma on the abdominal wall. We report the case of a 52-year-old woman who had had ulcerative colitis and a total colectomy and ileostomy 9 years before being evaluated for a 2-year history of intermittent small-bowel obstruction thought initially to be due to Crohn's disease. On examination, a clear parastomal hernia was detected and confirmed by a small-bowel series. At surgery the hernia was corrected, and her intermittent episodes of small-bowel obstruction resolved. A parastomal hernia should be considered as a cause of intermittent small-bowel obstruction in anyone who has a stoma. Careful history and physical examination should suffice in establishing a diagnosis.

Colitis, Ulcerative↗
PubMed1992

Relationship of drug use to involvement in school, home, and community activities: results of a large survey of adolescents.

All 7th, 9th, and 11th grade students in 129 school districts responded to a 466-variable survey that primarily assessed drug use but also contained questions about involvement in various activities. Meaningful relationships were obtained between students' involvement in school, family, and church activities and reported use of tobacco, alcohol, and marijuana. Factors reflecting the extent of parental supervision were also related to the reported use of those substances.

Activities of Daily Living↗
PubMed1986

[Nutrition physiologic studies of swine with ileorectal anastomoses. 1. Surgical method, biochemical and morphologic findings].

For the purpose of studying nutrient digestion and absorption in the small intestine, pigs were provided with ileo-rectal anastomoses. The anaesthetic and operation method is described. X-ray examinations do not show a significant backflow of digesta into the from colon cranially open towards the anastomosis as well as a totally intact sphincter ani. With the help of additional doses of highly digestible, N-free nutrients rich in energy (starch + saccharose), the operated animals achieved a growth development corresponding to that of intact control animals. For the assessment of the physiologic state of the animals, the concentrations in the serum of the total protein, of albumin, urea, glucose, calcium, inorganic phosphorus and creatinine as well as the activities of aspartate amino transferase and alkaline phosphatase were determined. These showed for the respective criteria changes conditioned by age and dependent on feed intake. The fixing of the anastomoses did not result in disturbances of nutritional or organic damages. Histologic studies of the mucosa of stomach, duodenum and jejunum did not show pathologic changes. The weight of stomach, duodenum and jejunum, determined in 2 live weight ranges, is identical for operated and intact animals in relation to the weight of the empty body of the animals. The weight of ileum, caecum and colon of the operated animals is significantly lower, due to inactivity atrophy. The tissue amount available for the intake of a volume unit (weight-volume index) is nearly identical for operated and intact animals in the duodenum and the jejunum. The index functionally increasing for intact animals from the jejunum to the ileum (stenosis due to temporary digesta congestion in the ileum) remained the same with anastomosis animals for 29 or 26 weeks resp. after the operation. As a result of the biochemical and morphological studies it was shown that animals with an ileo-rectal anastomosis are suitable for the determination of nutrient digestibility at the end of the ileum.

Alkaline Phosphatase↗
PubMed1986

Improved renal allograft function and survival following nonspecific blood transfusions. I. Induction of soluble suppressor factors inhibiting the mitogenic response.

A small number of blood transfusions (1-3) seems sufficient to improve the cadaveric renal allograft outcome, probably via induction of some nonspecific suppressive activity. This activity was assessed by the concanavalin A (Con A) enhancement method; when present, the response of freshly isolated patients' cells to a submitogenic dose of Con A was lowered, leading to a Con A ratio greater than 5, significantly (P less than 0.0001) higher than the one observed in normal controls or untransfused uremic patients. The correlation between this suppressive activity and graft outcome was determined. Thirty-five patients were studied over a 12-month period for graft function (creatinine level) and survival. Both parameters were significantly improved in the group of patients whose Con A ratio was greater than 5 after transfusions. A soluble suppressor factor, or factors, released into the supernatant of patients' lymphocytes cultured for 48 hr, seems responsible for this suppressive activity. Moreover this process is nonspecific, since it suppresses mitogenic response of cells isolated from normal untransfused volunteers, and could be observed when peripheral blood mononuclear cells were used, but not with purified adherent or nonadherent cells. Addition of indomethacin to the cells during the elaboration of the supernatant abolished this activity. However, amounts of PGE2 secreted into the supernatant during the 48 hr of culture could not be correlated with this suppressive activity. These findings suggest that induction of nonspecific immunosuppression by a few blood transfusions could predict a better kidney graft outcome.

Adult↗
PubMed1982

Biochemical composition of muscle in normal and semistarved human subjects: relevance to anthropometric measurements.

Anthropometric methods aimed at assessing muscle size in undernourished subjects assume a constant proportionality between the mass (i.e., size) and composition (specifically protein-energy content) of this tissue. This assumption was examined in three autopsy groups: controls (n = 11, sudden traumatic death), early semistarvation (n = 6), acute preterminal disease), and chronic semistarvation (n = 34, severe weight loss over time). Results of semistarved groups were expressed relative to respective control value. Early semistarvation produced no detectable change in muscle mass, protein, or total energy content (per gram wet weight), although RNA and glycogen were -50 to -70% of control value (p less than 0.05). Chronic semistarvation caused muscle atrophy (-54.2%), but not all measured constituents were reduced to the same degree. The results were H2O--52.9%, collagen--46%, noncollagen proteins--65.3%, total lipids--40%, DNA--54.1%, RNA--81.7%, glycogen--90.3%, and total energy--59.6%. Muscle per unit mass in chronic semistarvation thus reflects relatively more H2O and less protein and energy when compared to normal tissue. About 85 to 95% of muscle protein-energy loss can be detected by anthropometric measurements of muscle size; the remaining 5 to 15% depletion of protein and energy is masked by muscle compositional changes. Proper interpretation of anthropometric data requires an understanding of these unmeasured but important compositional differences in normal and semistarved muscle.

Anthropometry↗
PubMed1978

Moving the treatment of alcoholism into the medical mainstream.

This demonstration program for the treatment of alcoholism is based on the premise that alcoholism is a disease and that the primary care physician should play the central role in the overall management of alcoholism. The context of the Health Maintenance Organization (HMO) encourages the physician to assume responsibility for the care of the alcoholic and serves as the appropriate setting for the coordination of all modalities required.

Alcoholism↗
PubMed1976

Glycerolpropylsilane bonded phases in the steric exclusion chromatography of biological macromolecules.

Glycerolpropylsilane bonded phases have been found to control the adsorption and/or denaturation of proteins and nucleic acids on controlled porosity glass supports. The bonded-phase thickness is 18-19A while the amount of glycerol moiety varies from 80 to 150 mumoles/g depending on support pore diameter. It has been demonstrated that carbohydrate bonded supports may be used in the chromatography of proteins, nucleic acids, and polysaccharides.

Adsorption↗