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Biomedical subjects

M D Avery

Publications and source records attributed to M D Avery.

At least 19 recordsLinked to original sources
PubMed2001

Acute effect of exercise on blood glucose and insulin levels in women with gestational diabetes.

OBJECTIVE: To evaluate the effect of a single session of exercise (cycling), at rest (control condition) and at two intensity levels (low- and moderate-intensity exercise conditions), on blood glucose and insulin in pregnancy complicated by gestational diabetes mellitus (GDM). METHODS: A one-group repeated measures design was used. Women aged 18-38 with GDM, no other complications, not on insulin, and not exercising regularly were recruited. The women rested or exercised at the two intensities for 30 min and rested for 2 h after each session. Blood was sampled for blood glucose, insulin and hematocrit at baseline and every 15 min. RESULTS: There was no difference at baseline in blood glucose levels. The blood glucose level was significantly lower for each exercise condition compared to rest, and for moderate compared to low-intensity exercise (5.2 vs. 4.3 vs 3.9 mmol/l) at the end of exercise (30 min), and for the two exercise conditions compared to rest at 15 min after exercise (4.9 vs 4.4 vs. 4.0 mmol/l). By 45 min after exercise, the blood glucose values were nearly identical. The area under the curve for blood glucose was significantly lower for low- and moderate-intensity exercise than for rest (p = 0.01). The slope of change in insulin among the three conditions, from baseline to the 30-min session, approached significance (p = 0.065). The power for that analysis was 0.51. A sample of 23 would have been required to increase the power to 0.80. CONCLUSIONS: Significant declines in blood glucose level were observed during low- and moderate-intensity exercise compared to rest. These differences were gone by 45 min after exercise. Continued research should examine those with high body mass index and more pronounced hyperglycemia for further evaluation of the effect of exercise on blood glucose and insulin levels in women with GDM.

Adolescent↗
PubMed1997

Effects of a partially home-based exercise program for women with gestational diabetes.

OBJECTIVE: To examine the effectiveness of a partially home-based, moderate-intensity aerobic exercise program for women with gestational diabetes. METHODS: This was a randomized experimental design. Thirty-three women with gestational diabetes were randomly assigned to the exercise or the no-exercise group. Subjects underwent hemoglobin A1C assay and submaximal cycle ergometer fitness tests at baseline and at study conclusion. Subjects kept diaries of home fasting and 2-hour postprandial blood glucose determinations. Exercise subjects were asked to exercise for 30 minutes three to four times weekly at 70% of estimated maximal heart rate for the weeks of study participation. Two exercise sessions weekly were supervised by the investigator, and two were unsupervised at home. Control-group subjects were asked to maintain their current activity level. RESULTS: Daily fasting and postprandial blood glucose levels, hemoglobin A1C, incidence of exogenous insulin therapy, and incidence of newborn hypoglycemia were not different between the groups. There was a training effect in the exercise group (P = .005) but not in the control group (P = .25). A significant decline in daily grams of carbohydrate consumed was observed in the control group (P = .03), but not in the exercise group (P = .97). No complications were found in the subjects who exercised. CONCLUSIONS: A partially home-based exercise program did not reduce blood glucose levels, but did result in a modest increase in cardiorespiratory fitness. The intervention appeared safe.

Adult↗
PubMed1996

Remembering the nurse in the business advanced practice.

The question about whether advanced practice nurses maintain a nursing perspective in their practice has been asked. This article explores traditional practice differences between medicine and nursing and proposes a Cure-Care continuum as a framework to look at role delineation. The ANA Social Policy Statements and statements from national organizations representing advanced practice nurses are examined in looking further at advanced nursing practice. The statements reviewed and research to date focusing on outcomes of care by advanced practice nurses leads to the conclusion that the care is high quality and is delivered from a strong nursing perspective. Focus on this growing area of nursing should be on providing quality, comprehensive, cost-effective care in meeting health care needs in the future.

Humans↗
PubMed1995

Anemia and insufficient milk in first-time mothers.

Insufficient milk is a poorly understood problem that is often identified as a major reason for early discontinuation of breastfeeding. This study explored the relationship between anemia and insufficient milk in 630 first-time mothers. The frequency of anemia (postpartum hemoglobin < 10 g/dL) was 22 percent. Anemic mothers reported a higher level of symptomatology associated with insufficient milk and were more frequently classified as having insufficient milk syndrome. Mothers with the syndrome reported a shorter period of full breastfeeding, and weaned at an earlier age. They identified not having enough milk, baby nursing too often, and baby not gaining enough weight as the main reasons for discontinuing breastfeeding, compared with baby's disinterest and conflicts with school or work as main reasons among mothers not reporting symptoms related to insufficient milk syndrome. The study results suggest that anemia is associated with the development of insufficient milk, which in turn, is related to duration of full breastfeeding and to age at weaning.

Adolescent↗
PubMed1994

Women's experiences with breastfeeding longer than 12 months.

This prospective, longitudinal study was conducted to describe the experiences of 82 primiparas who breastfed longer than 12 months. They were compared with 541 primiparas who weaned their infants within the first year. Greater age, education, and weeks of exclusive breastfeeding were associated with longer duration of breastfeeding. More than two-thirds (68%) of the women who breastfed longer than one year returned to employment before their infant was 1 year old. The most frequently chosen reason for long-term breastfeeding was that breastfeeding was a special time for mother and baby that the mother was not ready to give up. Nearly half of the women reported breastfeeding their babies on demand. At 12 to 15 months, 54 percent of the babies slept in a crib in a separate room, and 37 percent slept in the same bed with their mother all or part of the night. Most mothers (57%) considered their support group to be slightly or moderately important in influencing their decision to breastfeed beyond a year, and 10 percent considered it to be extremely important. The major themes that emerged from women's comments were the importance of being strong in the face of social unacceptability, development of a close mother-child bond, and the naturalness of breastfeeding beyond 12 months. Health caregivers should recognize the emotional and interpersonal aspects of long-term breastfeeding, support the breastfeeding relationship, and avoid contributing to the development of "closet nursers" so that women may feel free to discuss their concerns about their child's health.

Adult↗
PubMed1986

An interlaboratory comparison of transformation in Syrian hamster embryo cells with model and coded chemicals.

Three independent laboratories tested eight "model" and five coded chemicals in the Syrian hamster embryo clonal transformation assay system to establish the intra- and interlaboratory reproducibility of the system and to identify sources of variability. When a common cell pool and the same lot of fetal calf serum were used, the three laboratories obtained consensus on the activity of eight model chemicals: five chemicals (benzo(a)pyrene, 7,12-dimethylbenz(a)anthracene, N-methyl-N'-nitro-N-nitrosoguanidine, nitroquinoline-N-oxide, and lead chromate) induced morphological transformation without exogenous metabolic activation and three (N-2-fluorenylacetamide, pyrene, and anthracene) produced no transformation response. Five coded chemicals (2,6-dichloro p-phenylenediamine, 4,4'-oxydianiline, cinnamyl anthranilate, dichlorvos, and reserpine), representative of environmental chemical classes, but not necessarily strong carcinogens, produced more equivocal responses in this interlaboratory study. Thus, while the assay can be used to distinguish between transforming and nontransforming chemicals in some cases, the intrinsic limitations in low transformation frequency and in achieving any dose-response results are major constraints to the use of this system in a routine testing program at the present time. Efforts to increase the transformation frequency or to amplify the expression of the transformed phenotype constitute some of the approaches which should be explored in order to overcome these limitations.

Animals↗
PubMed1985

Effects of varied cardioplegic perfusion pressure on myocardial preservation with critical coronary stenosis.

Inadequate delivery of cardioplegic solution distal to coronary artery stenosis may result in increased injury during ischemic arrest. This study was performed to determine the effects of cardioplegic perfusion pressure on cardioplegia delivery and myocardial preservation in hearts with critical coronary artery stenosis. Twenty dogs underwent 90 minutes of cold potassium cardioplegic arrest with partial occlusion of the circumflex coronary artery. Group 1 received cardioplegia at 50 mm Hg pressure, Group 2 at 90 mm Hg pressure, and Group 3 at 130 mm Hg pressure. It was found that cooling rates were 5.4 degrees, 9.1 degrees, and 18.2 degrees C per minute in the nonischemic area (p = 0.004) and 2.0 degrees, 4.5 degrees, and 7.9 degrees C in the ischemic area (p = 0.008) in Groups 1, 2, and 3, respectively. Total of cardioplegic solution flows were 86, 188, and 262 ml per minute per 100 gm in Groups 1, 2, and 3, respectively (p = 0.001). However, flow did not differ significantly between groups in the ischemic area. Rate of rise of left ventricular (LV) pressure decreased significantly in Groups 1 and 2 but not in Group 3 (p = 0.002). Other measured variables did not differ significantly between groups, although LV function curves showed less deterioration in the high-pressure groups. It is concluded that higher cardioplegic perfusion pressure resulted in more rapid cooling in normal and ischemic areas and slightly better preservation of ventricular function as measured by some indexes. However, preservation was generally good for each of the pressures for up to 90 minutes of ischemia when the septum was consistently cooled to 10 degrees C.

Adenosine Triphosphate↗
PubMed1981

Lung cancer model system using 3-methylcholanthrene in inbred strains of mice.

A model system has been established for studying lung carcinogenesis using intratracheal instillation of 3-methylcholanthrene in C3H/AnfCum and C57BL/Cum X C3H/AnfCum F1 (hereafter called BC3F1/Cum) mice. The animals in these studies were screened for adventitious agents and were free throughout their lifetime of two important lung viruses, Sendai virus and pneumonia virus of mice. Under these conditions, the occurrence of spontaneous and chemically indiced lung cancers was determined over the lifetime of the animals. Data were analyzed by the actuarial method for lung tumor probability. Probability was found to be dose and time dependent. Over 95% of the 3-methylcholanthrene-treated BC3F1/Cum and over 88% of the C3H/AnfCum mice were found at death to have pulmonary carcinomas. Tumors observed in animals which died up to 40 weeks on test were almost always squamous cell carcinomas (approximately 85%), while tumors which were observed in animals which died after 50 weeks were mainly alveolar adenocarcinomas (approximately 80%). Both tumors types metastasized widely. Spontaneous lung cancers (only alveolar adenocarcinomas were observed) occurred in these two strains at low frequency and were expressed late in life. Thus, the system described affords a suitable model to study the induction, expression, and progression of lung tumors under conditions where a vast majority of animals develop neoplasia.

Animals↗
PubMed1972

The formation of cholest-5-ene-3 ,26-diol as an intermediate in the conversion of cholesterol into bile acids by liver mitochondria.

1. When [(14)C]cholesterol was incubated with rat liver mitochondria, radioactive 26-hydroxycholesterol, 3beta-hydroxychol-5-enoic acid and other bile acids were isolated from the incubation mixture. 2. In the absence of added 26-hydroxycholesterol, the specific radioactivity of the 26-hydroxycholesterol formed from [(14)C]cholesterol during the incubation was higher than that of the 3beta-hydroxychol-5-enoic acid. Addition of increasing amounts of 26-hydroxycholesterol led to a progressive fall in the specific radioactivity, and to a progressive increase in the mass, of the 3beta-hydroxychol-5-enoic acid recovered at the end of the incubation. 3. It is concluded that 26-hydroxycholesterol is an intermediate in the formation of 3beta-hydroxychol-5-enoic acid from cholesterol. 4. Comparison of the specific radioactivity of the 26-hydroxycholesterol formed in the incubation mixture with that of the added [(14)C]cholesterol indicates that endogenous cholesterol in mitochondria is accessible to cholesterol 26-hydroxylase.

Acetylation↗
PubMedDate not supplied

Advanced nurse-midwifery practice.

The Clinical Practice Committee of the American College of Nurse-Midwives is frequently confronted with questions related to clinical practice. Many questions relate to specific clinical procedures and the position of the College as to their appropriateness for nurse-midwifery practice. This paper presents a discussion of a document developed to assist nurse-midwives when such questions arise.

Clinical Competence↗
PubMedDate not supplied

High-tech skills in low-tech hands. Issues of advanced practice and collaborative management.

Nurse-midwifery practice has been defined by the American College of Nurse-Midwives (ACNM) as "the independent management of essentially normal newborns and women ... occurring within a health care system which provides for medical consultation, collaborative management or referral .... "As the health care delivery system in the United States becomes increasingly complex and reliant on new forms of technology, it has become necessary to clarify roles and responsibilities for the nurse-midwife. In addition, mechanisms for acquiring new skills and for collaborating with physician colleagues must be well understood. A question frequently asked is where the boundaries of nurse-midwifery practice end and those of medical practice begin. Although practice scenarios vary for individual nurse-midwives and nurse-midwifery services, recent statements approved by the ACNM Board of Directors discuss these issues in an attempt to clarify the potentially confusing areas of collaboration and skill acquisition. This article explores the areas of expanded nurse-midwifery practice and collaborative management. Although individual clinical skills are not necessarily endorsed, a step-by-step approach that nurse-midwives can use for incorporation of new skills is presented. The concepts discussed will be a valuable tool to nurse-midwives in their practice.

Clinical Competence↗