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Biomedical subjects

R E Drake

Publications and source records attributed to R E Drake.

At least 19 recordsLinked to original sources
PubMed1992

Mental patients' attraction to the hospital: correlates of living preference.

Mental patients often show attraction to the hospital as a living alternative. In this study, 187 aftercare patients of an urban state hospital were examined for correlates of hospital attraction. Several variables, including background characteristics, psychosocial problems, psychiatric symptoms, substance abuse, and medication noncompliance, characterized the approximately 25% of the sample who showed hospital attraction. A logistic regression model for hospital attraction indicated that past hospital tenure, problems obtaining regular meals, positive symptoms of psychosis, and severe drug abuse contributed separately to the variance. The authors discuss the implications of these findings for treatment and public policy.

Activities of Daily Living↗
PubMed1992

Effect of increased neck vein pressure on intestinal lymphatic pressure in awake sheep.

Lymphatic vessels from the intestines drain into the thoracic duct, and the thoracic duct empties into veins in the neck. Thus increases in neck vein pressure (PNV) might slow intestinal lymph flow, provided the increased pressure is reflected upstream through the lymphatic vessels. To test the effect of increases in PNV on lymphatic pressure, we cannulated intestinal lymphatics in the direction of flow in six sheep. After the sheep recovered from surgery, we measured the pressure in the lymphatics (Px) as we increased PNV in steps. Px increased only slightly (but significantly) from 7.4 +/- 2.0 to 11.4 +/- 5.2 (SD) cmH2O when we increased PNV from baseline (0.8 +/- 2.4 cmH2O) to 37.4 +/- 4.1 cmH2O. However, when we simulated an increased lymph flow by infusing Ringer solution into the lymphatics at 1,000 microliters/min, Px increased to 24.6 +/- 7.0 cmH2O at PNV equal to 37.1 +/- 5.3 cmH2O. These results indicate that, at normal lymph flow rates, increases in neck vein pressure cause only small increases in intestinal lymphatic pressure. On the other hand, when lymph flow is elevated, increases in neck vein pressure may substantially increase lymphatic pressure and thus slow intestinal lymph flow.

Animals↗
PubMed1992

Increased venous pressure causes increased thoracic duct pressure in awake sheep.

The lymph from most organs drains through the thoracic duct and into veins in the neck. We hypothesized that increases in neck vein pressure (Pnv) are reflected through the thoracic duct to the lung lymphatic-thoracic duct junction. To test this, we cannulated the lung lymphatics in the direction of flow in four sheep. We advanced each cannula until it entered the thoracic duct. Thus the pressure at the tip of the lymphatic cannula (Px) was the pressure at the outflow of the lung lymphatics. We also placed a balloon into the superior vena cava. One to two days later, we measured Px in the awake sheep as we inflated the balloon and increased Pnv in steps to 25-45 cmH2O. We found no significant differences in Px and Pnv. Furthermore, Px closely followed Pnv after each step increase in Pnv. These results support our hypothesis that increases in Pnv cause increases in the outflow pressure to lung lymphatics.

Animals↗
PubMed1992

Diaphragmatic lymph vessel drainage of the peritoneal cavity.

We have studied the drainage of peritoneal fluid through the diaphragmatic lymph vessels in sheep. To measure the lymphatic flow rate, we cannulated the lymphatic vessels and timed the flow from the cannula. After we infused Escherichia coli endotoxin into awake sheep, the diaphragmatic lymph flow rate increased substantially. However, we found no increase in lymph flow in anesthetized acutely operated sheep. This indicates that studies in anesthetized animals may yield underestimates of diaphragmatic lymph flow. In sheep, many of the diaphragmatic lymph vessels drain to the caudal mediastinal lymph node. We cannulated an efferent vessel from that node in 5 sheep. Several days later we infused 100 ml/kg of Ringer's solution into the abdominal space of each awake sheep. In response, the lymph flow rate increased from 0.15 +/- 0.16 ml/min (mean +/- SD) to 0.50 +/- 0.17 ml/min. Our results are important because they demonstrate that diaphragmatic lymph flow increases substantially after fluid infusions into the abdominal space.

Animals↗
PubMed1992

Alcohol abuse, depression, and suicidal behavior in schizophrenia.

Alcohol use was correlated with depression and suicidal behavior in two independent studies of schizophrenic outpatients. Depression alone accounted for over 80% of the explained variance in suicidal behavior in both studies; alcohol use alone and the correlation between depression and alcohol use accounted for only small amounts of variance.

Adult↗
PubMed1991

Homelessness and dual diagnosis.

People who are dually diagnosed with severe mental illness and substance use disorders constitute 10%-20% of homeless persons. They are a heterogeneous and extremely vulnerable subgroup with complex, poorly understood needs. In this article recent research on the epidemiology, subject characteristics, and service needs of the dually diagnosed homeless population is reviewed. Also, the range of evolving approaches to providing social services, housing, and mental health and substance-abuse treatments; the relevant system issues and legal issues; and problems with current research, as well as future research directions, are discussed. The importance of the distinction between providing appropriate living environments and mental health treatments emerges throughout.

Alcoholism↗
PubMed1991

Characteristic hostility in schizophrenic outpatients.

In this study of 133 schizophrenic outpatients, we assessed characteristic hostility and correlates of hostility over a 6-month period. Results showed that 13 percent of the study group were characteristically violent, 18 percent were characteristically threatening, and another 21 percent were irritable and argumentative. About half (48%) were without hostility. A multiple regression model identified six variables--housing instability, hallucinations or delusions, schizoaffective diagnosis, lack of depression, alcohol use, and bizarre behavior--that together accounted for over 50 percent of the variance in observed characteristic hostility. Hostility also predicted rehospitalization and total inpatient days during 1-year followup. Implications of these findings for assessment and future research are discussed.

Adult↗
PubMed1991

Subjective experiences related to alcohol use among schizophrenics.

Comorbid alcohol use disorders are common in schizophrenia. Although a variety of explanatory hypotheses involving self-medication have been proposed, few data available regarding schizophrenic patients' subjective experiences while using alcohol. We report interview data from 75 DSM-III-R schizophrenic outpatients regarding their subjective responses to alcohol. Over half of our sample reported that alcohol improved social anxiety, tension, dysphoria, apathy, anhedonia, and sleep difficulties. Other nonpsychotic experiences were frequently improved as well. In contrast, no more than 15% of subjects reported that alcohol relieved any specific psychotic symptom; similar proportions of subjects reported that alcohol aggravated psychotic symptoms. Reporting that alcohol had a positive effect on nonpsychotic experiences was associated with having lifetime alcohol use disorders. Reporting that alcohol relieved psychotic symptoms was associated both with having lifetime alcohol use disorders and with the number of psychotic symptoms reported. We discuss the implications of these findings for understanding alcohol abuse and dependence among schizophrenics.

Adult↗
PubMed1991

Effect of outflow pressure on intestinal lymph flow in unanesthetized sheep.

Lymphatic vessels are important in removing excess fluid from the intestines and preventing intestinal edema. In this study we used the relationship between intestinal lymph flow rate (QL) and lymphatic outflow pressure (PO) to analyze the flow from intestinal lymphatics in unanesthetized sheep. We cannulated intestinal lymphatic vessels in six anesthetized sheep. One to 3 days after the surgery, we measured QL as we increased PO in steps. We found no QL decrease until PO greater than 15 cmH2O, but QL decreased significantly for PO greater than 15 cmH2O and was decreased to zero at PO = 34 +/- 13 (SD) cmH2O. In three experiments, we used the pressure pulses generated by the active lymphatic pump to estimate the pump stroke volume and frequency. These data indicate that increases in lymphatic pumping prevented a QL decreased for PO less than 15 cmH2O and the QL decrease for PO greater than 15 cmH2O was associated with lymphatic pump failure. When we increased portal venous pressure from baseline (10.1 +/- 4.1 cmH2O) to 24.3 +/- 6.2 cmH2O, lymph flow increased, but it was much more sensitive to outflow pressure. These results are important because they indicate that the ability of the lymphatics to remove fluid from edematous intestines may be compromised by small increases in lymphatic outflow pressure.

Animals↗
PubMed1991

Effect of thoracic duct drainage on hydrostatic pulmonary edema and pleural effusion in sheep.

Positive end-expiratory pressure (PEEP) increases central venous pressure, which in turn impedes return of systemic and pulmonary lymph, thereby favoring formation of pulmonary edema with increased microvascular pressure. In these experiments we examined the effect of thoracic duct drainage on pulmonary edema and hydrothorax associated with PEEP and increased left atrial pressure in unanesthetized sheep. The sheep were connected via a tracheostomy to a ventilator that supplied 20 Torr PEEP. By inflation of a previously inserted intracardiac balloon, left atrial pressure was increased to 35 mmHg for 3 h. Pulmonary arterial, systemic arterial, and central venous pressure as well as thoracic duct lymph flow rate were continuously monitored, and the findings were compared with those in sheep without thoracic duct cannulation (controls). At the end of the experiment we determined the severity of pulmonary edema and the volume of pleural effusion. With PEEP and left atrial balloon insufflation, central venous and pulmonary arterial pressure were increased approximately threefold (P less than 0.05). In sheep with a thoracic duct fistula, pulmonary edema was less (extra-vascular fluid-to-blood-free dry weight ratio 4.8 +/- 1.0 vs. 6.1 +/- 1.0; P less than 0.05), and the volume of pleural effusion was reduced (2.0 +/- 2.9 vs. 11.3 +/- 9.6 ml; P less than 0.05). Our data signify that, in the presence of increased pulmonary microvascular pressure and PEEP, thoracic duct drainage reduces pulmonary edema and hydrothorax.

Animals↗
PubMed1991

Estimation of the pulmonary microvascular reflection coefficient to protein in dogs.

We used a new technique to estimate the pulmonary microvascular membrane reflection coefficient to plasma protein (sigma d) in anesthetized dogs. In five animals we continuously weighed the lower left lung lobe and used a left atrial balloon to increase the pulmonary microvascular pressure (Pc). We determined the relationship between the rate of edema formation (S) and Pc and estimated the fluid filtration coefficient (Kf) as delta S/delta Pc. From the S vs. Pc relationship and Kf, we estimated the Pc at which S/Kf = 10 mmHg for each dog. This pressure (P10) was 38.0 +/- 5.8 (SD) mmHg, and the plasma protein osmotic pressure (pi c) was 14.9 +/- 3.7 mmHg. In five additional dogs in which we decreased pi c to 2.9 +/- 1.7 mmHg, P10 = 27.2 +/- 2.6 mmHg. The P10 vs. pi c regression line fit to the data from all 10 dogs was P10 = 0.92 pi c +/- 24.4 mmHg (r = 0.88). We estimated sigma d from the slope of the regression line as sigma d = square root of delta P10/delta pi c. With this technique, we estimated that, with 95% probability, sigma d lies between 0.72 and unity. This is higher than most previous sigma d estimates.

Airway Resistance↗
PubMed1991

Active lymphatic pumping and sheep lung lymph flow.

Active (intrinsic) lymphatic pumping may be an important factor determining lymph flow from the lungs. Unfortunately, in most experiments, it is very difficult to determine the influence of active pumping vs. passive factors on lymph flow. However, 1) the pumping activity (stroke volume and frequency) of isolated lymphatic segments varies nonlinearly with transmural pressure, and 2) the lung lymph flow from awake sheep varies nonlinearly with lymphatic outflow pressure. Accordingly, if lymphatic pumping significantly influences lung lymph flow, then it should be possible to describe the sheep lung lymph flow vs. outflow pressure data with the pumping activity data. To test this, we used published lymphatic pumping activity data to develop a mathematical model of the lymphatic pump for a segment of lymphatic vessel. Flow vs. outflow pressure relationships obtained from simulations with this model were very similar to the data from sheep. Our results indicate that both passive factors and active lymphatic pumping contribute to lymph flow, and our model may allow investigators to distinguish the effects of active pumping vs. passive factors in the regulation of lymph flow.

Anesthesia↗
PubMed1991

Housing instability and homelessness among rural schizophrenic patients.

OBJECTIVE: The authors examined housing instability among treated schizophrenic patients in a rural area and compared the findings with those from their previous study of urban patients. METHOD: Seventy-five patients with schizophrenia or schizoaffective disorder who were treated in a rural mental health center were assessed with research interviews and ratings by their clinical case managers. The patients were followed for 1 year to identify episodes of psychiatric hospitalization, incarceration, and literal homelessness. RESULTS: Of the 75 patients, 19 (25%) had housing situations characterized as unstable by their case managers. For the majority, housing instability signified tenuousness of living arrangements rather than literal homelessness. Noncompliance with medications, alcohol use, and negative symptoms accounted for 30% of the variance in unstable housing. During follow-up, the unstably housed patients, compared to those in stable living situations, were no more likely to be rehospitalized but were somewhat more likely to be jailed and significantly more likely to be literally homeless. CONCLUSIONS: In the authors' previous study of urban psychiatric patients, unstably housed patients were more likely to be literally homeless, highly symptomatic, and rehospitalized during follow-up than the rural patients with unstable housing. Better outcomes in the rural area appeared to be related to the greater availability of housing alternatives and to intensive case management. For patients with unstable housing in both settings, noncompliance with medications and substance abuse, as well as housing arrangements, should be assertively addressed.

Adult↗
PubMed1991

Abdominal lymph flow response to intraperitoneal fluid in awake sheep.

Lymphatic vessels are important in draining excess fluid from the abdominal space and preventing ascites. In sheep, diaphragmatic lymph vessels draining the abdominal space run to the caudal mediastinal lymph node and efferent vessels from the node drain into veins in the neck. To estimate the lymph flow response to excess intraperitoneal fluid in sheep, we cannulated a caudal mediastinal node efferent lymphatic in 5 sheep. After the sheep recovered from the surgery, the lymph flow (QL) was 154 +/- 161 (SD) microliters/min and the lymph protein concentration (CL) was 3.7 +/- 9 g/dl. Lymph flow decreased linearly with increases in lymphatic outflow pressure greater than 6 cmH2O. From this linear QL vs. outflow pressure relationship, we estimated the effective pressure driving lymph flow as the outflow pressure at which QL = 0. At baseline, the driving pressure was 24.7 +/- 14.0 cmH2O. After we infused Ringers solution (10% body weight) into the abdominal space, QL increased significantly to 7.0 +/- 4.1 times baseline and CL decreased significantly to 0.7 +/- 0.6 g/dl. Although the abdominal pressure increased significantly from 10.6 +/- 2.8 cmH2O to 15.8 +/- 2.1 cmH2O, we found no increase in lymphatic driving pressure.

Abdomen↗
PubMed1990

Diagnosis of alcohol use disorders in schizophrenia.

Alcohol use disorders are common comorbid conditions in schizophrenia, and their presence is associated with poor adjustment and poor treatment response. Standard alcohol assessment instruments have not been validated for use with schizophrenic patients, and several authors have questioned the validity of these patients' self-reports. A reliable and valid screening procedure for assessing alcohol use is needed. The present study used the following three methods to evaluate a rural sample of 75 outpatients with DSM-III-R schizophrenia or schizoaffective disorder: (1) clinical records; (2) research interviews using standard alcohol assessment instruments; and (3) case managers' ratings. In addition, consensus diagnoses, determined by combining information from all three methods with intensive case reviews, were used to determine the sensitivity and specificity of the other approaches. As expected, clinical evaluations frequently missed alcohol problems. Research interviews and case managers' ratings differentiated between alcoholic and nonalcoholic schizophrenic patients and were highly correlated. Case managers' ratings, which incorporated longitudinal observations of behavior and collateral reports as well as interview data, were more sensitive measures of current alcohol use disorders than research interviews. Subjects frequently manifested alcohol-related problems that interfered with community adjustment without the full dependence syndrome, suggesting that schizophrenic patients may be particularly vulnerable to negative effects of alcohol.

Adult↗