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Biomedical subjects

J B Gordon

Publications and source records attributed to J B Gordon.

65 records · Page 4Linked to original sources
PubMed1980

Social consequences of obesity.

Although social behavior has been studied by sociologists, the absence of references to such work is strikingly apparent in many discussions of the behavioral aspects of obesity. This paper presents some sociologic notions and research that can contribute to the health care professional's understanding of the problems of obesity and its treatment possibilities. One such approach could well be the use of weight control programs predicated on rearranging the social environment in which obese people live and eat.

Adolescent↗
PubMed1975

A disengaged look at Disengagement Theory.

This paper suggests that Disengagement Theory can be used as a theory of the middle-range, but not as a general theory about normal aging. This proposition is supported by an examination of key concepts, postulates and methods used to formulate the theory. By use of phenemological notions, we can see the concept of disengagement forces us to pay attention to the subjective meanings of aging people. It is necessary to disengage from the core statements of the theory and engage in a search for new methods to study the lived experiences of human beings in order to further our understandings of the processes of growing old.

Aged↗
PubMedDate not supplied

Developmental changes in synthesis of and responsiveness to prostaglandins I2 and E2 in hypoxic lamb lungs.

Previous studies have shown that the attenuated hypoxic pulmonary vasoconstriction (HPV) of young newborn lamb lungs was enhanced by cyclooxygenase inhibition. We sought to determine whether this reflected greater synthesis of and (or) responsiveness to dilator prostaglandins (PG). Protocol 1 measured responses to graded hypoxia and perfusate concentrations of 6-keto-PGF1alpha (the stable metabolite of PGI2) and PGE2 in isolated lungs from 1-day- and 1-month-old lambs. Protocol 2 compared dose responses and segmental vascular resistances during infusion of PGI2 and PGE2 in hypoxic, cyclooxygenase-inhibited, lungs from 1- to 2-day-old and 1- to 3-month-old lambs. Lungs of 1-day-old lambs with attenuated responses to 4% O2 had significantly higher perfusate concentrations of 6-keto-PGF1alpha and PGE2, but responses to both PGE2 and the more potent vasodilator, PGI2 did not differ with age. These data support the hypothesis that attenuated HPV in young newborn lamb lungs is due to increased synthesis of dilator PG, particularly PGI2.

6-Ketoprostaglandin F1 alpha↗
PubMedDate not supplied

Physiology of the native heart and Thermo Cardiosystems left ventricular assist device complex at rest and during exercise: implications for chronic support.

Studies of patients supported with a left ventricular assist device have considered determinants of acute survival emphasizing the role of right heart function. In patients with refractory heart failure awaiting heart transplantation, chronic left ventricular assist device implantation may provide an opportunity for rehabilitation before surgery if hemodynamics are adequate at rest and during activities of daily life. For the assessment of the efficacy of the left ventricular assist device in this setting, four patients in whom the HeartMate pneumatic left ventricular assist device had been implanted were tested during graded supine bicycle exercise with Doppler echocardiography interrogation and central hemodynamic measurements. Patients with left ventricular assist device increased total left ventricular-left ventricular assist device complex output with exercise as Fick cardiac output increased from 5.7 +/- 1.5 to 8.6 +/- 3.1 L/min (mean +/- standard deviation). In two patients, peak left ventricular assist device rate and output were either present at the start of exercise or reached at mid-exercise and were associated with abrupt increases in left ventricular filling pressures (pulmonary capillary wedge pressure = 9 to 27 mm Hg and 12 to 24 mm Hg, respectively). During exercise, left ventricular end-diastolic size and pressure increased as right ventricular dimensions decreased or remained the same (patients 1, 3, and 4: 1.7 to 1.8 cm, 4.7 to 3.9 cm, and 2.6 to 1.8 cm, respectively) despite increased right atrial filling pressures, implying a decrease in functional right ventricular diastolic compliance. Although the left ventricular assist device functioned as a series pump at rest, Fick cardiac output exceeded left ventricular assist device output during exercise consistent with parallel ejection of the left ventricle through the native aortic valve. During exercise, residual left ventricular function may contribute to the hemodynamic response by (1) active filling of the left ventricular assist device to reduce filling time and to overcome left ventricular assist device inflow cannula impedance, (2) augmentation of total cardiac output with parallel ejection out of the native aortic valve, or (3) reduction of ventricular interaction-related changes in functional right ventricular diastolic compliance. When residual left ventricular function is sufficient, hemodynamics with exercise may be limited by peak left ventricular assist device rate. Although right ventricular function may affect acute postoperative survival, residual left ventricular function and peak left ventricular assist device rate may be important determinants of exercise performance during chronic implantation. A preliminary model of factors affecting the "left ventricular-left ventricular assist device complex" performance at rest and during exercise is presented.

Adult↗
PubMedDate not supplied

Left ventricular assist device support of medically unresponsive pulmonary hypertension and aortic insufficiency.

Most centers consider medically unresponsive pulmonary hypertension an absolute contraindication to orthotopic cardiac transplantation because the alternative surgical therapy, heterotopic graft placement, is associated with decreased survival, although most patients normalize their pulmonary hemodynamics postoperatively. Orthotopic transplantation in patients with elevated, but responsive pulmonary pressures, also is associated with an increased operative mortality rate and decreased long-term survival. The authors present the case of a patient with medically unresponsive pulmonary hypertension who was mechanically supported in an effort to improve his orthotopic transplant candidacy and decrease his risk. After informed consent, a HeartMate left ventricular assist device (LVAD) was inserted and the pulmonary hemodynamic response was monitored. Immediately before LVAD insertion, the pulmonary artery pressure (PA) was 74/28 mmHg with a transpulmonary gradient (TPG) of 28 mmHg, and a pulmonary vascular resistance (PVR) of 6.6 Wood units, despite prolonged dobutamine, milrinone, and prostaglandin E1 infusions. After 10 weeks of LVAD support, pressure and resistance improved; pulmonary artery pressure was 28/15 mmHg, transpulmonary gradient was 15 mmHg, and pulmonary vascular resistance was 2.8 Wood units. This patient subsequently underwent an uneventful orthotopic heart transplant. At 1 year after transplantation, pulmonary artery hemodynamics were normal (PA 34/14 mmHg, TPG at 8 mmHg, and PVR at 1.5 Wood units). The authors recommend the consideration of LVAD placement in patients with medically unresponsive pulmonary artery hypertension to assess PA responsiveness and improve the patient's orthotopic cardiac transplant candidacy and decrease the operative risk. However, several weeks may be needed for normalization of pressure and resistance.

Adult↗