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Biomedical subjects

R E Drake

Publications and source records attributed to R E Drake.

At least 163 records · Page 9Linked to original sources
PubMed1986

Effect of bronchial blood flow on pulmonary artery wedge pressure with pulmonary embolism.

Discrepancies between pulmonary artery wedge pressure (WP) and left atrial pressure (LAP) occur with pulmonary embolism. Theoretically, this discrepancy could be affected by the bronchial circulation or by the type of embolus. To test this in dogs, we determined the effects of embolism induced by glass beads and by air upon the WP with intact vs. ligated bronchial blood flow to the left lower lobe. For those animals receiving pulmonary air infusions, the pulmonary artery pressure, WP, and pulmonary vascular resistance showed significant (p less than .05) elevations with no change in LAP. There were no changes in these values when the bronchial blood flow was interrupted. When glass beads (120 mu) were injected into the left lower lobe, the pulmonary artery pressure and pulmonary vascular resistance rose as in the air emboli groups (p less than .05); however, WP remained at control values and approximated LAP. Obstructing the bronchial blood flow did not change this response. We conclude that the discrepancy between WP and LAP depends upon the type of embolus and is not affected by bronchial blood flow.

Animals↗
PubMed1986

Equivalent circuit technique for lymph flow studies.

Lymph vessels branch and interconnect in a manner similar to a complex electronic circuit. Accordingly, we have applied circuit analysis techniques to the analysis of lymphatic systems. A lymph vessel is cannulated and the "equivalent circuits" are determined for the parts of the vessel upstream and downstream of the site of cannulation. Each equivalent circuit consists of a single resistor in series with a single pressure source. A diode is included to represent the lymphatic valves. The lymph flow rate may be determined by calculating the flow in the circuits when they are connected to each other. This technique can be applied to larger lymph trunks that receive lymph from many tissues.

Animals↗
PubMed1986

Lung lymph flow during volume infusions.

We investigated the effect of intravenous isotonic crystalloid solution infusion on lung lymph flow. Tracheobronchial lung lymph vessels were cannulated in 13 anesthetized dogs. The lymph flow rate was measured 1) with the lymph flowing against atmospheric pressure (QL), and 2) with the pressure at the outflow end of the lymph cannula equal to systemic venous pressure (QLV). QL and QLV were measured alternately in each lymph vessel. In one group of nine dogs, the base-line QL and QLV were 18 +/- 9 and 13 +/- 6 (SD) microliter/min, respectively (P less than 0.05). QL increased by 4.8 +/- 1.4-fold, and QLV increased by 3.5 +/- 2.1-fold during a 4-h infusion of 25 ml X kg-1 X h-1 of Ringer solution. QLV was significantly less than QL at all times. The increases in lymph flow were caused primarily by a reduction in the effective resistance of the lymph vessels with little rise in the pressure driving lymph from the lungs. Because QLV flowed against systemic venous pressure, the increase in QLV was blunted by a 3.1 +/- 2.3 cmH2O rise in venous pressure during the infusions. In the remaining four dogs, we infused Ringer solution rapidly in order to raise venous pressure to greater than 15 cmH2O. This caused QL to increase by 25 +/- 7-fold; however, QLV decreased to zero. We conclude that elevations in venous pressure which occur during volume infusions oppose lung lymph flow and lead to accumulation of excess fluid in the lungs.

Animals↗
PubMed1986

Overestimation of sheep lung lymph contamination.

We have previously reported that lymph from the chronic sheep lung lymph preparation contains 25-60% lymph from nonpulmonary sources. In subsequent studies we found that the lymph flow rate from cannulated lymph vessels depends on the resistance and position of the lymph cannula. Because we did not account for these factors in our estimate of the amount of nonpulmonary lymph in the sheep lung lymph preparation, our data were not accurate. We probably overestimated the amount of nonpulmonary lymph. However, the presence of nonpulmonary lymph remains a potentially serious problem with the sheep lung lymph preparation.

Animals↗
PubMed1986

Effect of systemic venous pressure elevation on lymph flow and lung edema formation.

Pulmonary lymph drains into the thoracic duct and then into the systemic venous circulation. Since systemic venous pressure (SVP) must be overcome before pulmonary lymph can flow, variations in SVP may affect lymph flow rate and therefore the rate of fluid accumulation within the lung. The importance of this issue is evident when one considers the variety of clinical interventions that increase SVP and promote pulmonary edema formation, such as volume infusion, positive-pressure ventilation, and various vasoactive drug therapies. We recorded pulmonary arterial pressure (PAP), left atrial pressure (LAP), and SVP in chronic unanesthetized sheep. Occlusion balloons were placed in the left atrium and superior vena cava to control their respective pressures. The superior vena caval occluder was placed above the azygos vein so that bronchial venous pressure would not be elevated when the balloon was inflated. Three-hour experiments were carried out at various LAP levels with and without SVP being elevated to 20 mmHg. The amount of fluid present in the lung was determined by the wet-to-dry weight ratio method. At control LAP levels, no significant difference in lung fluid accumulation could be shown between animals with control and elevated SVP levels. When LAP was elevated above control a significantly greater amount of pulmonary fluid accumulated in animals with elevated SVP levels compared with those with control SVP levels. We conclude that significant excess pulmonary edema formation will occur when SVP is elevated at pulmonary microvascular pressures not normally associated with rapid fluid accumulation.

Animals↗
PubMed1986

Inpatient psychosocial treatment of chronic schizophrenia: negative effects and current guidelines.

In the inpatient psychosocial treatment of schizophrenia, therapies that are intense and overstimulating often promote or prolong regression and negatively affect long-term adjustment. These approaches fail to take into account the chronicity of the disorder, the special vulnerabilities of the schizophrenic patient, and the appropriate goals of an inpatient admission. Based on a review of these problems, the authors offer several prescriptions for inpatient psychotherapy of schizophrenia: modest, well-defined goals; gentle, supportive, educational interactions with the patient; inclusion of the patient's support system and outpatient caregivers in the treatment; and attention to long-term adjustment as well as to short-term symptom removal.

Chronic Disease↗
PubMed1986

Depression, hopelessness and suicide in chronic schizophrenia.

Hospital records for 104 schizophrenic patients, 15 of whom subsequently committed suicide, were rated blindly for individual depressive symptoms comprising DSM III major depressive episode, and for hopelessness. Our results indicate that a large proportion of schizophrenic patients experienced major depressive episodes, and that these can be reliably identified. Presuicidal schizophrenics also experienced depressed mood, but only a minority developed the full syndrome; they typically exhibited the psychological, but not somatic symptoms. The relationship between depression and suicide disappears when hopelessness is taken into account.

Adult↗
PubMed1986

Suicide among schizophrenics: a comparison of attempters and completed suicides.

Schizophrenics who completed suicide were compared with those who made suicide attempts, on the basis of blind ratings of previous hospital records and follow-up interviews with treating clinicians. Results indicated that the two groups were relatively distinct. Suicides tended to live alone and to feel depressed, hopeless, worthless, and suicidal. Attempters, on the other hand, lived with their families or others and were less likely to manifest several features of depression during a period in hospital. In evaluating suicide potential among schizophrenics, living situation and mental state changes indicating depression, suicidal intent, worthlessness, and hopelessness are more important than a history of suicidal behaviour.

Female↗
PubMed1986

Sheep lung lymph shunting.

The caudal mediastinal lymph node (CMN) has several efferent lymph vessels in most sheep. When investigators cannulate one of the CMN efferent vessels in order to collect lung lymph, it is possible that lymph may be shunted between the cannulated vessel and other vessels which drain from the CMN into the systemic veins. If shunting does occur then an increase in venous pressure could cause lymph to be shunted to the cannulated lymph vessel. This would increase the flow of lymph from the cannula and could falsely indicate that lung lymph flow had increased. To test this possibility we cannulated CMN efferent vessels in 7 sheep and then used a balloon to raise the pressure in the superior vena cava. Because uncannulated CMN efferent vessels ultimately drain into the superior vena cava, an increase in pressure may cause lymph to be shunted through the lymph cannula. We found, however, that lymph flow increased in only one of seven sheep and conclude that lymph shunting is uncommon when operative preparation includes meticulous ligation of collateral common efferent lymph vessels.

Animals↗
PubMed1985

Maturity of ego defenses in relation to DSM-III axis II personality disorder.

Independent raters assessed a cohort of 307 inner-city men on three dimensions of psychosocial dysfunction: the Health-Sickness Rating Scale (HSRS), axis II of DSM-III, and dominant choice of ego mechanisms of defense. Two thirds of the 74 men with personality disorders and three fourths of the 55 men with the low scores (0 to 65) on the HSRS primarily used immature defense mechanisms (ie, projection, schizoid fantasy, passive aggression, dissociation, hypochondriasis, and acting out). Only 10% of men without personality disorders and only 10% of men with HSRS scores of over 70 were noted to favor such defenses.

Adolescent↗
PubMed1985

Effect of cardiac output on extravascular lung water estimates made with the Edwards lung water computer.

The Edwards lung water computer system uses the thermal-dye indicator technique to estimate the lung extravascular fluid volume (EVLW). The authors tested the effect of changes in cardiac output (CO) on EVLW estimates made with the lung water computer in six dogs anesthetized with halothane. Baseline CO was 2.5 +/- 1.3 l/min (mean +/- SD); CO subsequently was increased either by 220% or decreased by 70% by either giving 0.5 mg/kg of isoproterenol or increasing the inspired halothane (1-4%), respectively. There was a significant correlation between the estimated EVLW and CO in each animal (P less than 0.05) such that a 50% decrease in CO from baseline caused an approximately 40% increase in estimated EVLW. Postmortem examination showed that the lungs were not edematous, even though the lung water computer data indicated that severe pulmonary edema had developed at reduced COs. At increased COs, estimated EVLW decreased. The authors conclude that the Edwards lung water computer overestimates lung water, possibly because the thermal indicator diffuses into nonpulmonary as well as pulmonary tissue. The overestimate is greatest at low cardiac outputs.

Animals↗
PubMed1985

Surfactants identified in lung lymph and their ability to act as abhesives.

Phospholipid has been extracted from pulmonary lymph collected from 10 dogs. Thin-layer chromatography was used to identify phosphatidylcholine (PC) 55.6 +/- 2.9%, sphingomyelin 21.3 +/- 1.7%, phosphatidylethanolamine 11.2 +/- 4.9%, and lysophosphatidylcholine 5.9 +/- 0.8%. All extracts proved highly surface active, reducing the surface tension of saline to 27.7 +/- 0.7 dyn/cm upon 80% film compression and increasing the maximum contact angle on glass (theta) from 7 +/- 1 to 47.4 +/- 1.4 degrees. The hydrophobic properties induced on glass were further demonstrated by the ability to cause saline to withdraw and expose a dry surface. A standard adhesion test was used to measure the "tack" produced by the major proteins in lymph. However, when the surface energy of the hydrophilic glass surfaces was reduced by a monolayer of lymph phospholipid extract or an equivalent mixture of synthetic surfactants, the adhesive force was reduced by 79 +/- 4% for albumin and 55 +/- 4% for globulin. As a 0.1% liposomal suspension, PC gave 55% release with albumin. Reversible bonding of the lumen of lymph vessels by the "tacky" proteins present is discussed as a possible factor contributing to the large changes in flow resistance known to occur in the pulmonary lymphatic system.

Adhesives↗
PubMed1985

Suicide attempts associated with akathisia.

The authors report two cases of impulsive suicide attempts associated with akathisia. In both cases, suicidal ideation appeared suddenly, concurrent with neuroleptic-induced akathisia, and disappeared when the akathisia was treated.

Adult↗
PubMed1985

A validity study of axis II of DSM-III.

The authors examine DSM-III personality disorders in a longitudinally followed community sample of middle-aged inner city men. Eighty-six (23%) of the subjects received an axis II diagnosis of personality disorder. Although these men received relatively little psychiatric attention, they were severely impaired in terms of how they felt about themselves, how others saw their global mental health, and their ability to work and to love. When the strong overlap with alcoholism was controlled for, personality disorder was clearly related to adaptive problems that manifested by early adolescence. The evidence suggests that early deficiencies of biology, environmental support, and ego strength contribute to the development of personality disorder.

Adaptation, Psychological↗
PubMed1984

Suicide among schizophrenics. Who is at risk?

Schizophrenic patients are at high risk for suicide. Most of the clinical features of the illness which have been associated with suicide remain speculative. This study provides an empirical test of hypothetical risk factors from the literature. Results indicate that schizophrenic patients who kill themselves have high internalized standards of performance which are often congruent with past educational attainments. They are also realistically aware of the effects of their illness, feel inadequate in relation to their goals, and fear further mental disintegration. Their affect is depressed, and they express hopelessness about the future. Suicidal ideation and explicit suicide threats often precede death. These results can be used to assess suicide risk among schizophrenic patients.

Adult↗
PubMed1984

Effect of endotoxin on lung fluid balance in unanesthetized sheep.

We used a gravimetric technique to test for increased pulmonary capillary permeability after Escherichia coli endotoxin infusion in unanesthetized sheep. The sheep were chronically prepared with cannulas placed into the left atrium and pulmonary artery 1-2 wk before the experiments. We estimated pulmonary capillary pressure (Pc) as the average of pulmonary arterial and left atrial pressures, and used the modified method of Pierce to estimate the ratio of extravascular fluid weight (EVF) to blood-free dry weight. In 15 sheep we inflated a left atrial balloon to raise Pc to -10.7, 5, 10, or 15 mmHg above plasma oncotic pressure (IIc) for 3 h, then measured EVF. EVF averaged 4.0 +/- 0.2 (base line), 4.3 +/- 0.1, 4.5 +/- 0.1, and 5.1 +/- 0.5 (SD), respectively, for the four levels of Pc - IIc. We gave seven additional sheep 1 microgram/kg of E. coli endotoxin (0127:B8) and measured EVF after 3 h of stable Pc. Endotoxin increased Pc in each sheep. EVF was higher than control for the endotoxin sheep with Pc - IIc greater than -1. This finding is consistent with an increase in pulmonary capillary permeability caused by endotoxin. However, EVF was not elevated in the endotoxin sheep with Pc - IIc less than 1 mmHg. This shows that the increased permeability was insufficient to cause edema unless Pc was elevated. Thus endotoxin may cause edema by two mechanisms, 1) an increase in capillary permeability, and 2) an increase in Pc.

Animals↗
PubMed1984

Effect of lymphatic cannula outflow height on lung microvascular permeability estimations.

Estimates of the pulmonary microvascular membrane reflection coefficient (sigma) and permeability-surface area product (PS) are frequently made with the assumption that a percent change in transmicrovascular fluid flux (Jv) will be represented by an equal percent change in the lymph flow rate (QL) from a single cannulated lung lymph vessel. To test this, we measured QL in seven anesthetized dogs with the outflow end of the lymph cannula set at several heights (H) above and below the lung hilus. The left atrial pressure was then elevated to increase Jv, and QL was again measured at several H's. The percent increase in QL at elevated left atrial pressure depended on H. We used the QL data and lymph and plasma protein concentrations to estimate sigma and PS with a modified form of the Kedem and Katchalsky equations. The calculated values varied considerably with H. Our results indicate that changes in Jv are not represented by equal changes in QL. Therefore, techniques for estimating permeability that depend upon QL as an estimate of Jv may lead to erroneous estimates of sigma and PS.

Animals↗