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Biomedical subjects

R Artal

Publications and source records attributed to R Artal.

At least 19 recordsLinked to original sources
PubMed1992

Exercise and pregnancy.

Despite the theoretic risks to both mother and fetus listed in this article, exercise in pregnancy conducted in moderation appears to be safe in most cases. The current published literature includes the following consistent findings: 1. Women who exercised before pregnancy and continued to do so during pregnancy tended to weigh less, gain less weight, and deliver smaller babies than controls. 2. All women, regardless of initial level of physical activity, decrease their activity as pregnancy progresses. 3. No information is available to assess whether active women have better pregnancy outcome than their sedentary counterparts. No information is available on sedentary women. 4. Physically active women appear to tolerate labor pain better. 5. Exercise can be used as an alternative and safe therapeutic approach for gestational diabetes. Pregnancy should not be a state of confinement, and cardiovascular and muscular fitness can be reasonably maintained. Restriction of physical activity should be dictated by obstetric and medical indications only. Health care providers should inform pregnant women of potential risks and individualized exercise prescription as indicated and necessary.

Exercise↗
PubMed1991

Exercise in gestational diabetes. An optional therapeutic approach?

Forty-one patients with gestational diabetes requiring insulin were enrolled in a randomized study to investigate the efficacy of an exercise program in normalizing glucose tolerance. Seventeen of 21 patients completed the exercise program while maintaining normoglycemia and obviating insulin therapy. Maternal and neonatal complications did not differ between the study and control groups. The type of program described appears to be safe and can serve as a model for exercise prescription for pregnant diabetic women to attain improved glucose tolerance.

Adult↗
PubMed1990

Influence of postmortem time and temperature on osteoinductive activity of demineralized microperforated ethylene oxide-sterilized syngeneic bone implant in the rat.

Bone morphogenetic protein is labile and easily inactivated by many extracorporeal factors. It is crucial to establish whether delay in retrieval of donor bone and ambient holding temperature of the donor body influence osteoinductivity of bone left in situ. Of ten adult rats that were killed, five were kept at 4 degrees and five at room temperature. Femurs were harvested at 24, 36, 48, 72, and 168 hours. After processing, segments were implanted in 20 four-week-old syngeneic rats for 14 days. The level of osteoinduction was evaluated histologically. It was excellent in the 4 degrees group in the 24-, 36-, and 48-hour specimens but less advanced at 72 hours. Bone taken from the room temperature group showed findings identical to those kept at 4 degrees through 36 hours, but osteoinduction was less advanced at 48 hours and absent at 72 hours. No bone formed at 168 hours in either temperature group. The following observations were made. (1) Osteoinductivity of demineralized bone left in situ after death was unexpectedly stable. (2) Retrieval time was extended by donor cooling. (3) Microperforated demineralized bone actively induced new bone formation. (4) Ethylene oxide does not inhibit osteoinduction when correctly applied for sterilization. If confirmed in humans, retrieval of bone to be used for osteoinduction could be delayed for some hours, particularly if the donor was immediately refrigerated. This would increase the effective number of bone tissue donors and utilize an undeveloped resource.

Animals↗
PubMed1989

Exercise prescription in pregnancy: weight-bearing versus non-weight-bearing exercise.

Bicycle ergometry (non-weight-bearing exercise) and treadmill (weight-bearing exercise) were compared to assess physiologic responses to similar work loads. A total of 22 subjects at 29.3 +/- 1.6 (+/- SEM) weeks' gestation who performed non-weight-bearing exercise were compared with 15 similarly fit subjects at 26.1 +/- 2.3 weeks' gestation who performed weight-bearing exercise at three submaximal levels. Measurements by indirect calorimetry indicate preferential carbohydrate use during non-weight-bearing exercise at submaximal levels.

Adult↗
PubMed1989

Effects of seminal ejaculate on the biomechanical properties of chorioamniotic membranes.

We investigated the effects of seminal ejaculate on the biomechanical properties of chorioamniotic membranes obtained and processed immediately after normal term vaginal deliveries. Study samples were exposed to seminal ejaculate and control samples to buffered normal saline. Both the samples and controls were incubated for periods of 1, 4 and 24 hours, after which a load-deformation curve was derived for each. Four biomechanical parameters were analyzed for each sample and control: modulus of elasticity, rupture tension, work to rupture and strain to rupture. Exposure to seminal ejaculate was associated with an increase in the modulus of elasticity, work to rupture and rupture tension, reflecting a change in the elastic component of the mechanical properties. No significant change was observed in the strain to rupture. We hypothesize that these changes may indicate an alteration in the ability of chorioamniotic membranes exposed to seminal ejaculate to dissipate mechanical stress, resulting in their predisposition to premature rupture.

Amnion↗
PubMed1988

Physiological insulin action is opposed by beta-adrenergic mechanisms in dogs.

To investigate the possible role of adrenergic mechanisms in modulating glucose homeostasis during physiological insulin changes, we studied the effects of alpha-, beta-, or combined alpha- and beta-adrenergic blockade on glucose production (Ra) and utilization (Rd) via isotope ([3-(3)H]glucose) dilution during nonstressful, nonhypoglycemic conditions in response to physiological insulin changes in conscious dogs. Without adrenergic blockade, infusion of insulin at 0.275 mU.kg-1.min-1 (control) caused glucose to fall from 92 +/- 4 to 82 +/- 4 mg/dl over 30 min, because of transient fall in Ra from 2.8 +/- 0.4 to 2.3 +/- 0.3 mg.kg-1.min-1, which recovered to base line by 30 min. There was a later rise in Rd to 3.9 +/- 0.4 mg.kg-1.min-1 at 45 min, but no counter-regulatory hormonal changes (glucagon, cortisol, epinephrine, and norepinephrine) to account for these findings in glucose kinetics. alpha-Blockade alone led to an initial rise in base-line insulin and consequent fall in glucose, associated with a transient fall in Ra but no change in Rd; infusion of insulin led to a further small fall in glucose, with no change in Ra, but with a rise at 30 min in Rd similar to controls. beta-Blockade alone led to an initial fall in insulin and modest rise in glucose; insulin infusion led to a greater rate of fall in glucose than in controls (from 112 +/- 6 to 78 +/- 7 mg/dl over 30 min).(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic alpha-Antagonists↗
PubMed1988

Circulating catecholamines and glucagon in infants of strictly controlled diabetic mothers.

Previous studies have demonstrated impaired perinatal adaptation of glucose homeostasis with inappropriately low levels of catecholamines and glucagon in newborn infants born to diabetic mothers. To investigate whether these neonatal changes are related to maternal metabolic control, we sequentially measured plasma glucose, catecholamines and glucagon in the neonatal period in 10 infants born to well-controlled mothers with class B diabetes mellitus after uncomplicated pregnancies. Good glycemic control in the mothers resulted in appropriate counterregulatory hormone responses in the neonatal period, similar to those described in infants born to normal mothers. The significant rise in plasma epinephrine and glucagon paralleled the establishment of euglycemia, further suggesting that these hormones are important for perinatal adaptation of glucose homeostasis.

Blood Glucose↗
PubMed1988

Transient ischemic attack: a complication of mitral valve prolapse in pregnancy.

A case of transient ischemic attack presumably due to cardiogenic thromboembolism during pregnancy is described in a 32-year-old woman. The patient had documented mitral valve prolapse which was uncomplicated until this episode. This is the first report in the literature of such a complication during pregnancy. The clinical management is described.

Adult↗
PubMed1987

Peripheral dopamine metabolism in polycystic ovary syndrome.

It has been proposed that a relative dopamine deficiency or an increased sensitivity of the gonadotrope to dopamine may explain the elevated luteinizing hormone (LH) levels characteristic of polycystic ovary syndrome. To study one aspect of this issue, that of peripheral dopamine metabolism in polycystic ovary syndrome, we measured the conversion of dopamine to norepinephrine after intravenous dopamine infusions in women with polycystic ovary syndrome and in matched controls. In addition, we measured urinary metabolites of dopamine and norepinephrine, which reflect in part central catecholamine turnover, after daily ingestion of L-dopa with carbidopa, which increases brain dopamine levels. After dopamine infusion in women with polycystic ovary syndrome and in matched controls, steady state levels of plasma dopamine, norepinephrine, and the ratio of dopamine/norepinephrine were similar in the two groups. Similarly, urinary metabolites of dopamine, norepinephrine, and their ratios were not different in patients and controls after L-dopa with carbidopa. We suggest that no major alterations in dopamine metabolism exist in these patients with polycystic ovary syndrome.

Adult↗
PubMed1986

Pulmonary responses to exercise in pregnancy.

The pulmonary responses of 88 pregnant women were compared to those of 39 nonpregnant control subjects during different exercise intensities. At rest the pregnant women had higher tidal volumes, oxygen consumption, carbon dioxide production, and respiratory exchange ratio. With increased work loads the pregnant volunteers have consistently lagged behind the nonpregnant control subjects for every parameter, which indicates a decrease in pulmonary reserve and inability to exercise anaerobically.

Adult↗
PubMed1986

Fetal heart rate responses to maternal exercise.

The fetal heart rate responses to mild, moderate, and strenuous maternal exercise were studied in 45 healthy subjects. In the majority of cases, the fetal heart rate increased during and after maternal exercise. Fetal bradycardia was recorded in five fetuses; this appears to be a sporadic event. There was no correlation between the individual fetal heart responses, gestational age, exercise intensity, and maternal circulating catecholamines.

Blood Glucose↗
PubMed1986

Neonatal jitteriness of unknown origin and circulating catecholamines.

Jitteriness is a common problem affecting neonates. Although the cause can sometimes be determined by history or conventional laboratory evaluations, nevertheless, in many instances the cause of the jitteriness is unknown. To determine if either intracranial hemorrhage (ICH) or elevated catecholamines are responsible for jitteriness in neonates, we studied 34 healthy term neonates with normal hematocrits, serum glucose, Ca, Mg, Na, K and P. Thirteen of the infants had jitteriness as their only clinical problem. There were no differences in Apgar scores, birthweight, or gestational age in the two groups. Norepinephrine levels were significantly elevated in the jittery group as compared to the control group: 1276 +/- 574 vs. 914 +/- 338, p less than 0.05. Epinephrine levels were not different in the two groups. Intracranial hemorrhage was not found in any of the patients. Jittery neonates have increased sympathetic activity. What influence the increased levels have on other metabolic and hormonal systems is yet to be determined.

Humans↗
PubMed1986

Putative hypothalamic glucoreceptors play no essential role in the response to moderate hypoglycemia.

The response to insulin-induced hypoglycemia includes increased plasma levels of glucagon, epinephrine, norepinephrine, cortisol, and growth hormone. This integrated response is thought to be mediated via sympathetic afferent pathways emanating from the ventromedial hypothalamus. However, the precise loci of the receptors that sense glucopenia are not known. In this study, we investigated the importance of putative forebrain glucoreceptors to the systemic response to hypoglycemia. Three protocols were performed. Protocol 1: the systemic response was observed in conscious dogs to hypoglycemia induced by infusion of insulin at a high rate (150 mU/min). Protocol 2: the effect of concomitant bilateral, intracarotid glucose infusion on the response to intravenous insulin was examined. Intracarotid glucose infusion rates were chosen to yield central euglycemia in the face of systemic hypoglycemia. Protocol 3: as a control for protocol 2, glucose was infused at low rates into the systemic circulation, yielding hypoglycemia in both central and systemic blood. When insulin was infused at 150 mU/min, without glucose replacement (protocol 1; N = 6), plasma insulin increased from 14 +/- 3 to 335 +/- 35 microU/ml at 60 min (P less than 0.001). Glucose fell from basal (104 +/- 3 mg/dl) to 38 +/- 3 mg/dl (P less than 0.001). Significant increases were observed in epinephrine (basal, B: 63 +/- 8; steady state, SS: 1762 +/- 582 pg/ml; P less than 0.007), norepinephrine (B: 209 +/- 33, SS: 650 +/- 133 pg/ml; P less than 0.01), and glucagon (B: 256 +/- 35, SS: 467 +/- 35 pg/ml; P less than 0.03). In addition, endogenous glucose production (Ra) increased from 72 +/- 4 to 108 +/- 9 mg/min (P less than 0.02) despite frank hyperinsulinemia. Infusion glucose into the carotid arteries at 204 +/- 10 mg/min (protocol 2; N = 7) during a 4-h systemic insulin infusion was sufficient to prevent jugular hypoglycemia [jugular glucose, Gj, B: 100 +/- 3, SS (90-160 min): 101 +/- 3 mg/dl; P greater than 0.70], but not peripheral hypoglycemia (Gp, B: 102 +/- 2, SS: 55 +/- 3 mg/dl; P less than 0.001). Despite carotid glucose replacement, counterregulatory responses were still observed in epinephrine (B: 98 +/- 14, SS: 466 +/- 127 pg/ml; P less than 0.04) and norepinephrine (B: 213 +/- 19, SS: 474 +/- 133 pg/ml; P less than 0.05).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1985

C-reactive protein in pregnancy and in the postpartum period.

Serum C-reactive protein levels were measured by means of the nephelometric immunoassay technique in 215 pregnant women at various gestational ages. The results indicate a positive correlation of serum C-reactive protein levels with gestational age. In addition, we studied serum C-reactive protein concentrations in 37 pregnant women in labor and during the postpartum period. Delivery was accomplished by either the vaginal or abdominal route and was associated with significant C-reactive protein production.

C-Reactive Protein↗
PubMed1985

Opiate modulation of glucose turnover in dogs.

We examined the effect of opiate infusion and of opiate blockage on glucose turnover in the basal state, using isotope dilution techniques in trained conscious dogs (n = 5). After a primed-continuous infusion of 3-3H glucose to steady state specific activity (90 minutes), infusion of one of the following was given: D-met2 pro5 enkephalinamide (DMPE), a potent morphine-like opiate, 0.5 mus g/kg/min; naloxone, an opiate antagonist, 1.25 mg followed by 10 mus g/min; or saline control. Infusion of DMPE led to a fall in glucose from 92 +/- 3 to 87 +/- 3 mg/dL by 60 minutes (P less than 0.05), associated with a rise in glucose utilization (Rd) from 3.0 +/- 0.4 to 3.9 +/- 0.6 mg/kg/min by 30 minutes (P less than 0.05); a transient rise in glucose production (Ra; from 3.2 +/- 0.4 to 4.3 +/- 0.4 mg/kg/min; P less than 0.05). Changes in counterregulatory hormones did not account for these findings; insulin was unchanged during all infusions; glucagon showed small late rises at 75 minutes during both DMPE and naloxone infusion; cortisol rose by 30 and 15 minutes, respectively, of DMPE and naloxone infusion; epinephrine rose transiently after 5 minutes of naloxone but was unchanged during DMPE, and norepinephrine was unchanged throughout. Saline infusion had no effects on any of these indices. We conclude that a potent opiate with morphine-like effects (DMPE) can lower glucose in dogs by enhancing peripheral glucose utilization independently of hormonal changes.

Animals↗
PubMed1985

Indomethacin and salicylate decrease epinephrine-induced glycogenolysis.

Epinephrine (E) produces an immediate (0-30 minutes) rise in hepatic glucose production (Ra), largely due to activation of glycogenolysis; thereafter, E-stimulated gluconeogenesis becomes the major factor maintaining glucose production. To investigate the possible role of arachidonic acid metabolites on Ra during E stimulation, we infused E in trained conscious dogs before and during administration of two inhibitors of arachidonic acid metabolism, indomethacin (INDO) and salicylate (S). On separate days, experimental animals were treated with both oral and IV INDO and oral acetylsalicylic acid and IV sodium salicylate. Ra and glucose utilization (Rd), both in mg x kg-1 min-1, were calculated by isotope dilution using 3-3H-glucose. After achieving steady state specific activity, control (C) and experimental animals (n = 6 per group) received E (0.1 ug x kg-1 min-1) for 150 minutes, raising plasma levels to approximately 1500 pg/mL in each group. In C, plasma glucose (G; mg/dL) rose by 17 +/- 5 at 10 minutes and 19 +/- 3 at 20 minutes due to an initial spike in Ra (2.7 +/- 0.2 to 4.9 +/- 0.5; P less than 0.01) at 10 minutes. INDO and S treatment attenuated this initial (10-20 minutes) rise in G (P less than 0.05) due to a lower stimulated Ra at 10 minutes (3.3 +/- 0.1 with INDO; 3.0 +/- 0.5 with S; P less than 0.05). After 20 minutes Ra was not different in the 3 groups; no overall differences in Rd, glucose clearance, or plasma insulin levels occurred with INDO or S treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗