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Biomedical subjects

R E Drake

Publications and source records attributed to R E Drake.

At least 145 records · Page 8Linked to original sources
PubMed1989

Housing instability and homelessness among aftercare patients of an urban state hospital.

Homelessness as a dimensional concept reflecting instability of community living arrangements was examined in an urban state hospital's sample of 187 aftercare patients with chronic mental illness. According to ratings by outreach clinicians, 17 percent of the patients were predominantly homeless, and 10 percent were occasionally homeless over the six months before evaluation. Younger, male patients were more likely to be homeless. Homelessness was strongly associated with abuse of alcohol and street drugs, treatment noncompliance, and a variety of psychosocial problems and psychiatric symptoms. Homeless patients were viewed by their primary clinicians as attracted to the hospital as a living alternative and, during prospective one-year follow-up, had a much higher rate of rehospitalization.

Adult↗
PubMed1989

Substance abuse among the chronic mentally ill.

Substance abuse was examined in a group of 187 chronic mentally ill patients living in the community. According to ratings by aftercare clinicians, approximately onethird of the sample abused alcohol, street drugs, or both during the six months before evaluation. Patients who were dually diagnosed with substance abuse and mental illness differed from those with mental illness alone in several respects: they were younger and more often male; were less able to manage their lives in the community in terms of maintaining regular meals, adequate finances, stable housing, and regular activities; showed greater hostility, suicidality, and speech disorganization; and had poorer medication compliance. In addition, they were nearly twice as likely to be rehospitalized during one-year follow-up. Substance abuse, appeared to add the problems of disruptive, disinhibited, noncompliant behaviors to chronic mental illness.

Adult↗
PubMed1988

Health care of the chronically mentally ill: the culture broker model.

The chronically mentally ill tend to receive inadequate medical care for nonpsychiatric illnesses and to have poor health care status. Their medical problems lead to excessive morbidity and mortality and adversely affect their adjustment to psychiatric illness. The authors argue that many of the barriers to medical care for these patients can be overcome by using case managers as "culture brokers"-persons who provide bridges between the worlds of the chronically mentally ill and medical providers. This paper presents the culture broker model and its roots in anthropology, and illustrates its application to the medical care of the chronically mentally ill with case examples.

Adult↗
PubMed1988

Lymphatic function in the liver after hepatic venous pressure elevation.

The liver lymphatic system plays an important role in removing excess fluid from the hepatic tissue. A complete analysis of the liver lymphatic system would be difficult. However, we used a simple circuit-analysis technique to represent the intrahepatic portion of the lymph system as a single pressure source (PL) pushing lymph through a single resistance (RL). Liver lymphatic vessels were cannulated in nine halothane-anesthetized dogs. The lymphatic vessel outflow pressure (PO) was varied by raising the outflow end of the cannula. Lymph flow from the cannula (QL) decreased linearly with PO, and we calculated RL as -delta PO/delta QL and PL as the extrapolated PO at which QL = 0. At base line, PL = 8.5 +/- 2.9 cmH2O, and RL = 0.05 +/- 0.03 cmH2O.min/microliter. After we increased inferior vena caval pressure from 5.8 +/- 2.7 to 15.2 +/- 2.5 cmH2O, PL increased significantly to 13.7 +/- 3.4 cmH2O, and RL decreased to 0.02 +/- 0.02 cmH2O.min/microliter (P less than 0.05). The results indicate that increases in QL occur because the effective pressure pushing lymph from the liver (PL) increases, and the effective resistance of the intrahepatic lymph vessels (RL) decreases.

Algorithms↗
PubMed1988

Superior vena caval pressure elevation causes pleural effusion formation in sheep.

The effect of superior vena caval pressure (SVCP) elevation on the formation of pleural effusions (PE) was studied in sheep. Through a right thoracotomy, a Silastic cuff was placed around the superior vena cava. Catheters for monitoring SVCP and pulmonary artery pressure (PAP) were also placed. After a 1- to 3-wk recovery period, we measured the SVCP, PAP, cardiac output, and plasma protein concentration (Cp). We then elevated the SVCP to various levels from base line [5.3 +/- 2.6 (SD) mmHg] to 33 mmHg. The cardiac output, PAP, and Cp were remeasured 1-2 h and 24 h after SVCP elevation. At the end of the 24-h period, the animals were killed. The PE volume and pleural fluid protein concentration (Cpl) were measured, and the Cpl/Cp was calculated. PE generally did not occur until the SVCP was elevated above 15 mmHg. To study the effect of the thoracotomy on the subsequent pleural effusion, we studied six additional sheep in which we did not perform a thoracotomy. In these animals, the SVCP was elevated to between 5 and 28 mmHg for 24 h by use of a 16-Fr balloon catheter placed via a left external jugular vein and a right carotid-external jugular shunt. We found that the PE volume, for a given SVCP elevation, was similar to that present in sheep that received a thoracotomy. For all sheep the volume of PE was related to SVCP by the equation PE (ml) = 0.24e0.26SVCP, r = 0.85. In the sheep without a thoracotomy, Cpl/Cp rose with increasing volume of PE. Our data demonstrate that elevation of SVCP greater than 15 mmHg for 24 h results in the formation of PE. The rise in Cpl/Cp with PE volume suggests that filtration through the pleural vessels is not the major contributor to PE formation.

Animals↗
PubMed1988

Pulmonary microvascular permeability to fluid and macromolecules.

Research in pulmonary microvascular permeability has been a hot bed of activity for the last 20 years, primarily because increases in permeability contribute to the development of some forms of pulmonary edema in humans. New techniques and animal preparations have lead to significant advances, and most of these advances have been well described in several recent reviews. Unfortunately, there is still confusion over what the techniques measure and when they can be used to make reliable permeability estimates. Furthermore, we have a different point of view than previous authors. For instance: 1) we question the assumption that lymph flow rate is proportional to filtration rate, whereas other authors have implicitly assumed this relationship to be true; 2) we believe that the wide range of filtration coefficients measured with various techniques may be narrowed by consideration of the types of errors likely to result with each technique; 3) we place more emphasis than previous authors on the potential problems caused by the collection of impure lung lymph and the possibility that lymph composition may be altered within lymph nodes. For these reasons we believe that readers may benefit from a review of the techniques used in pulmonary permeability studies written from our perspective.

Animals↗
PubMed1988

Mental patients' attitudes toward hospitalization: a neglected aspect of hospital tenure.

Recent research on hospital tenure has neglected mental patients' attitudes toward hospitalization. The authors consider problems with past research on these attitudes and examine "living preference"--the patient's preference for living in the hospital or the community. Assessments of patients' living preferences were obtained from clinicians working with 187 chronically mentally ill patients in a state hospital aftercare program. These assessments strongly predicted both components of hospital tenure--rehospitalization and in-hospital days--during a 1-year follow-up. The authors point out the conceptual, heuristic, and practical clinical advantages of examining living preference rather than traditional correlates of hospital tenure.

Aftercare↗
PubMed1987

Outflow pressure reduces lymph flow rate from various tissues.

We previously reported that the very act of cannulating a lung lymph vessel could alter the unique flow characteristics that existed within the lymphatic before cannulation. We postulated that this phenomenon could hold true for lymphatics draining any organ within the body. Since it is frequently important to know the relationship between the transmicrovascular fluid flux and true lymph flow rate, it would be critical that a cannulated lymphatic vessel have the same flow characteristics as those uncannulated vessels draining the same organ. In order to test our hypothesis we cannulated lymph vessels draining the heart, liver, small intestine, kidney, and skeletal muscle. By altering the lymphatic outflow pressure (normally related to systemic venous pressure) and by using lymphatic cannulas of various resistance, we were able to demonstrate that lymph flow varied linearly with lymphatic outflow pressure in every organ. By increasing transmicrovascular fluid flux and lymph flow rate in each organ we were also able to demonstrate that effective resistance of the lymphatic vessels and the effective pressure driving lymph flow varied as a function of the physical characteristics of the organ under investigation. Characteristic effective resistances of the heart, liver, skeletal muscle, kidney, and small intestine lymphatics decreased by 83, 40, 61, 36, and 50%, respectively. Along with these changes in effective resistance, the effective lymph driving pressure in the same organs varied by 49, 0, 257, 0, and 63%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

A model of the lung interstitial-lymphatic system.

Our model of the pulmonary interstitial-lymphatic system is based on the assumption that the lung interstitial space can be divided into two compartments. The first compartment (C1) contains the terminal lymph vessels. Increases in the fluid pressure within this compartment, along with increased pressure generated by lymph vessel pumping, cause the lymph flow rate to increase. The lymph vessels run through the second compartment (C2) which we believe represents the perivascular spaces. Increases in the fluid volume of C2 cause the lymph vessels to dilate and this causes lymph vessel resistance to decrease. Normally the lymph flow rate equals the microvascular filtration rate so that lung fluid volume is constant. According to our model, increases in filtration rate cause fluid to collect in C1 and C2. The resulting increase in fluid pressure in C1, increased lymph vessel pumping, and the decrease in lymph vessel resistance in C2 cause lymph flow to increase. Eventually, the lymph flow rises to equal the filtration rate and lung fluid volume becomes constant again. The results of simulations with our model indicate that decreases in lymph vessel resistance are essential for lymph flow to increase substantially as edema develops.

Extracellular Space↗
PubMed1987

Effect of endotoxin on diaphragm lymph contamination in unanesthetized sheep.

The preparation for collecting lung lymph from sheep caudal mediastinal lymph node (CMN) efferent vessels is widely used to study the effects of endotoxin on lung microvascular permeability. However, there are nonpulmonary lymph vessels that drain into the CMN along with the afferent lymph vessels from the lung. Thus CMN lymph is a mixture of lymph from the lung and diaphragm lymph vessels as well as from other nonpulmonary lymph vessels. We studied the effect of 0.5-1.0 microgram/kg Escherichia coli endotoxin on the flow rates in diaphragm and CMN efferent lymph vessels (Qdi and QCMN, respectively) in unanesthetized sheep. For the time period between 2 and 5.5 h after endotoxin QCMN was increased from its base line of 7.2 +/- 4.4 (SD) to 17.3 +/- 10.6 ml/h and the lymph-to-plasma protein concentration ratio (L/PCMN) had increased from 0.68 +/- 0.11 to 0.81 +/- 0.06. During the same time period, Qdi was 4.5 +/- 3.1 ml/h compared with 1.0 +/- 0.8 ml/h at base line and the diaphragm lymph-to-plasma protein concentration ratio (L/Pdi) was 0.92 +/- 0.07 (base line = 0.74 +/- 0.15). The increases in flow rate and protein concentration were significant for each type of vessel (P less than 0.05). We conclude that the period of increased QCMN and L/PCMN after endotoxin is associated with an increase in Qdi and L/Pdi. Thus, it is difficult to determine how much of the CMN lymph response comes from the lungs and how much comes from diaphragm lymph vessels.

Animals↗
PubMed1987

Elevation of superior vena caval pressure increases extravascular lung water after endotoxemia.

In many sheep Escherichia coli endotoxin results in pulmonary hypertension, increased microvascular permeability, pulmonary edema, and increased central venous pressure. Since lung lymph drains into the systemic veins, increases in venous pressure may impair lymph flow sufficiently to enhance the accumulation of extravascular fluid. We tested the hypothesis that, following endotoxin, elevating the venous pressure would increase extravascular fluid. Thirteen sheep were chronically instrumented with catheters to monitor left atrial pressure (LAP), pulmonary arterial pressure (PAP), and superior vena caval pressure (SVCP) as well as balloons to elevate LAP and SVCP. These sheep received 4 micrograms/kg endotoxin, and following the pulmonary hypertensive spike the left atrial balloon was inflated so that (PAP + LAP)/2 = colloid osmotic pressure. It was necessary to control PAP + LAP in this way to minimize the sheep-to-sheep differences in the pulmonary hypertension. We elevated the SVCP to 10 or 17 mmHg or allowed it to stay low (3.2 mmHg). After a 3-h period, we killed the sheep and removed the right lungs for determination of the extravascular fluid-to-blood-free dry weight ratio (EVF). Sheep with SVCP elevated to 10 or 17 mmHg had significant increases in EVF (5.2 +/- 0.1 and 5.6 +/- 1.2) compared with the sheep in which we did not elevate SVCP (EVF = 4.5 +/- 0.4). These results indicate that sustained elevation in central venous pressure in patients contributes to the amount of pulmonary edema associated with endotoxemia.

Animals↗
PubMed1987

Lymph flow from edematous dog lungs.

We measured the flow rate (QLV) from cannulated lung lymph vessels in anesthetized dogs. Low-resistance lymph cannulas were used and the vessels were cannulated at the lung hilus. When we increased left atrial pressure to 42.9 +/- 5.7 (SD) cmH2O (base line = 6.6 +/- 4.6 cmH2O), the lungs became edematous and QLV increased from a base line of 20.4 +/- 21.5 microliters/min to 388 +/- 185 microliters/min. QLV plateaued at the higher level. We also measured the relationship between lymph flow rate and the height of the outflow end of the lymph cannula. From this relationship, determined at the end of the period of elevated left atrial pressure, we calculated the effective resistance and pressure driving lymph from the lungs. We also cannulated lymph vessels in the downstream direction and estimated the effective resistance and pressure opposing flow into the part of the lymphatic system between the lung hilus and the veins (extrapulmonary lymph vessels). We found that the effective resistance of the extrapulmonary part of the lymph system (0.042 +/- 0.030 (SD) cmH2O X min X microliter-1) was large compared with the resistance of the lymph vessels from the lungs (0.026 +/- 0.027). These data indicate that the resistance of the extrapulmonary part of the lung lymph system limits the maximum flow of lymph from edematous lungs.

Animals↗
PubMed1987

Lowered pulmonary arterial pressure prevents edema after endotoxin in sheep.

Escherichia coli endotoxin causes increased capillary membrane permeability and increased pulmonary arterial pressure (PAP) in sheep. If the pulmonary hypertension extends to the level of the microvasculature, then the increased microvascular pressure may contribute to the pulmonary edema caused by endotoxin. We tested the hypothesis that reducing the pulmonary hypertension would reduce the amount of edema caused by endotoxin. Twelve sheep were chronically instrumented with catheters to measure PAP, left atrial pressure, and central venous pressure. The sheep were divided into two groups. One group (E) of six sheep received an intravenous infusion of 4 micrograms/kg of E. coli endotoxin. The second group (E + SNP) received the same dose of endotoxin as well as a continuous infusion of sodium nitroprusside (SNP) to reduce PAP. Three hours after the endotoxin infusions, the sheep were terminated and the extravascular fluid-to-blood-free dry weight ratios of the lungs were determined (EVF). The base-line PAP was 17.5 +/- 2.7 mmHg. A two-way analysis of variance demonstrated a significant difference (P less than 0.01) in PAP between the E and E + SNP groups. Although PAP in each group varied as a function of time, the difference between the two groups did not. The mean PAP for the E + SNP group (20.9 +/- 1.5 mmHg) was lower than the E group PAP of 27.3 +/- 2.1 mmHg after the endotoxin spike. Furthermore, the E + SNP group EVF (3.9 +/- 0.2) was significantly less than the EVF of the E group (4.7 +/- 0.5).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Using family psychoeducation when there is no family.

High familial expressed emotion, which may be a specific form of social overstimulation, has been linked to schizophrenic relapse and rehospitalization. Research on expressed emotion has led to a new generation of demonstrably effective family treatments for schizophrenia that rely heavily on psychoeducational techniques. Although most schizophrenic patients do not live with families, the family psychoeducational model has not been applied in nonfamilial living settings. The authors report two examples in which the family psychoeducational model was successfully used in group living situations and discuss the implications of expressed emotion and family psychoeducation for schizophrenic patients who live in nonfamilial settings.

Anger↗