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Biomedical subjects

R E Drake

Publications and source records attributed to R E Drake.

At least 127 records · Page 7Linked to original sources
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↗
PubMed1990

Changes in microvascular permeability with acceleration of edema in dog lungs.

Elevation of left atrial pressure to 25-40 mmHg causes continuous pulmonary edema formation in dog lungs. However, after 5-120 min, the rate of edema formation often increases (acceleration of edema). Acceleration of edema could be associated with an increase in microvascular membrane permeability because an increase in permeability would cause fluid to filter through the microvascular membrane more rapidly. To test the hypothesis that acceleration is associated with increased permeability, we used the continuous weight-gain technique to estimate the pulmonary microvascular membrane filtration coefficient (Kf) before and after acceleration of edema in 10 dogs. Acceleration occurred 36 +/- 38 (SD) min after elevation of left atrial pressure to 35.2 +/- 5.4 mmHg. Rate of weight gain increased from 0.47 +/- 0.17 g/min before acceleration to 0.88 +/- 0.26 g/min (P less than 0.05) after acceleration of pulmonary edema. Kf was increased from initial values of 0.058 +/- 0.027 to 0.075 +/- 0.029 ml.min-1.mmHg-1 (P less than 0.05) after acceleration. In five additional dogs we cannulated lung lymphatics and determined the lymph to plasma protein concentration ratio (CL/CP) before and after acceleration. CL/CP increased from base-line values of 0.37 +/- 0.07 to 0.44 +/- 0.06 (P less than 0.05) after acceleration. Both the increase in Kf and CL/CP data support the hypothesis that acceleration of edema is due, in part, to a slight increase in microvascular membrane permeability. However, the findings could also have been caused by an increase in interstitial conductance, washout of interstitial proteins, or alveolar flooding.

Animals↗
PubMed1990

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

We used lymph flow rate (QL) to lymphatic vessel outflow pressure (Po) relationships to analyze lymphatic flow in five unanesthetized sheep with liver lymphatic cannulas. The olecranon was the zero reference level for pressures. Increases in Po did not change QL until Po exceeded 19 +/- 4 (SD) cmH2O. However, for Po greater than 19 +/- 4 cmH2O, QL decreased linearly with increases in Po. We fit regression lines to the QL vs. Po data for Po greater than 19 cmH2O and estimated the effective lymphatic resistance (RL) as -delta Po/delta QL. The effective pressure driving lymph (PL) was the Po at which QL = 0. At baseline, RL = 0.18 +/- 0.10 cmH2O.min.microliter-1 and PL = 29.6 +/- 3.4 cmH2O. When we increased hepatic vein pressure by 5.7 +/- 1.7 cmH2O, QL increased to 6.2 +/- 3.2 times baseline, RL decreased to 0.050 +/- 0.015 cmH2O.min.microliter-1, and PL increased to 37.1 +/- 3.5 cmH2O (P less than 0.05). Thus 1) liver lymph flow is very sensitive to increases in hepatic vein pressure, 2) there is a substantial QL vs. Po plateau for liver lymphatics, and 3) after hepatic venous pressure elevations, liver lymph flow increases as if it were driven by a higher pressure through a lower resistance.

Animals↗
PubMed1990

The effect of anesthesia and surgery on diaphragmatic lymph vessel flow after endotoxin in sheep.

Increases in diaphragmatic lymph vessel flow (Qdi) may be important in preventing ascites because diaphragmatic lymph vessels drain the peritoneal space. However, lymphatic vessel function may be depressed in anesthetized, open chested animals. To test this hypothesis, we cannulated diaphragmatic lymph vessels in five sheep which were anesthetized with 1-2% halothane. We performed a thoracotomy and cannulated a diaphragmatic lymph vessel in each sheep. Then we infused 0.75-1.0 micrograms/kg of E. coli endotoxin intravenously and we measured Qdi and the lymph protein concentration for 2-4 hrs. The data were compared to previously reported data for five unanesthetized sheep (J. Appl. Physiol. 62:706-710, 1987). At baseline Qdi = 0.8 +/- 0.7 (SD) in the anesthetized sheep and 1.0 +/- 0.8 ml/hr in the unanesthetized sheep. After endotoxin, Qdi increased to 4.5 +/- 3.1 ml/hr in the unanesthetized sheep (p less than 0.05) but Qdi did not change in the anesthetized sheep. However, the lymph protein concentration increased similarly in each group, indicating that endotoxin caused the same degree of injury in each group. Our results indicate that diaphragmatic lymph vessel function is depressed in anesthetized, open chested sheep.

Analysis of Variance↗
PubMed1989

Depression in schizophrenia: current guidelines to treatment.

Depressive symptoms and syndromes in schizophrenia are common but heterogeneous with respect to etiology, presentation, course, and treatment. Based on a comprehensive differential diagnosis that identifies ten clinical subgroups, the authors review relevant treatment studies and offer current treatment guidelines. The clinical recommendations focus on addressing underlying problems such as medication side effects and substance abuse, attempting to identify and treat medication-responsive syndromes, and preventing suicide. The categories and treatments presented here are expected to evolve as researchers continue to elucidate clinically meaningful syndromes and to develop specific treatments. Nevertheless, current knowledge suggests that many schizophrenics with depression and depression-like symptoms can be treated effectively.

Combined Modality Therapy↗
PubMed1989

Alcohol use and abuse in schizophrenia. A prospective community study.

The authors examined patterns of alcohol use among 115 DSM-III schizophrenics discharged from the state hospital and participating in an urban aftercare program. According to ratings by mobile outreach clinicians, 45% of the patients used alcohol, and 22% were clearly abusing alcohol. Alcohol use was associated with younger age, male sex, street drug use, medication noncompliance, lack of psychosocial supports, increased symptomatology, chronic medical problems, and a higher rate of rehospitalization. Even minimal drinking, not considered alcohol abuse by clinicians, predicted rehospitalization during 1-year prospective follow-up.

Adult↗
PubMed1989

Intestinal lymphatic flow during portal venous hypertension.

We used a circuit-model technique to analyze the flow from intestinal lymphatics. Postnodal lymph vessels from the small intestine were cannulated in five halothane-anesthetized dogs. We measured the flow rate from the cannula (QL) as we held the outflow end of the cannula at several heights above the site of cannulation. At each cannula height we calculated the pressure at the outflow end of the lymphatic (Po) as Po = QL X cannula resistance + height of the outflow end of the cannula above the cannulation site. Then we determined a best-fit regression line for QL vs. Po. The effective lymphatic resistance (RL) was estimated from the regression line as -delta Po/delta RL and the effective pressure driving lymph flow (PL) was taken as the Po at which QL = 0. At base line, RL = 0.039 +/- 0.018 (SD) cmH2O.min.microliters-1 and PL = 5.2 +/- 2.4 cmH2O. When we raised the portal venous pressure from 11.4 +/- 4.0 cmH2O (base line) to 34.4 +/- 9.0 cmH2O, RL decreased by only 26 +/- 11%, but PL rose by 160% to 13.6 +/- 8.7 cmH2O (P less than 0.05). Thus our data indicate that increases in portal venous pressure to 34.4 +/- 9.0 cmH2O cause intestinal lymph flow to increase primarily because of increases in the effective PL.

Animals↗
PubMed1989

Effect of lysophosphatidylcholine on the filtration coefficient in intact dog lungs.

Lysophosphatidylcholine (lyso-Pc) is a lysophospholipid normally found in low concentrations in the lung. At high concentrations lyso-Pc, instilled into the airways, causes pulmonary edema. We tested the hypothesis that the edema caused by lyso-Pc was due to an increase in pulmonary microvascular membrane permeability. In 11 anesthetized dogs we continuously weighed the left lower lobes (LLL) while instilling lyso-Pc (20 mM) into the LLL airways. After 30 min we determined the microvascular membrane fluid filtration coefficient (Kf) from the relationship between the rate of LLL weight gain and the pulmonary microvascular pressure. Kf was not significantly different between the lyso-Pc-treated lobes (0.048 +/- 0.018 ml.min-1.mmHg-1) vs. control lobes (0.067 +/- 0.031 ml.min-1.mmHg-1). Our data do not support the hypothesis that lyso-Pc, instilled into the airways, causes an increase in pulmonary microvascular permeability.

Animals↗