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Biomedical subjects

R E Drake

Publications and source records attributed to R E Drake.

At least 73 records · Page 4Linked to original sources
PubMed1997

Protein osmotic pressure gradients and microvascular reflection coefficients.

Microvascular membranes are heteroporous, so the mean osmotic reflection coefficient for a microvascular membrane (sigma d) is a function of the reflection coefficient for each pore. Investigators have derived equations for sigma d based on the assumption that the protein osmotic pressure gradient across the membrane (delta II) does not vary from pore to pore. However, for most microvascular membranes, delta II probably does vary from pore to pore. In this study, we derived a new equation for sigma d. According to our equation, pore-to-pore differences in delta II increase the effect of small pores and decrease the effect of large pores on the overall membrane osmotic reflection coefficient. Thus sigma d for a heteroporous membrane may be much higher than previously derived equations indicate. Furthermore, pore-to-pore delta II differences increase the effect of plasma protein osmotic pressure to oppose microvascular fluid filtration.

Animals↗
PubMed1997

Lymph flow in sheep with rapid cardiac ventricular pacing.

Increases in systemic venous pressure (Pv) associated with heart failure cause an increase in microvascular fluid filtration into the tissue spaces. By removing this excess filtrate from the tissues, lymphatic vessels help to prevent edema. However, the lymphatics drain into systemic veins and an increase in Pv may interfere with lymphatic flow. To test this, we cannulated caudal mediastinal node efferent lymphatics in sheep. We used rapid cardiac ventricular pacing (240-275 beats/min) to cause heart failure for 4-7 days. Each day we determined the lymph flow rate two ways. First, we adjusted the lymph cannula height so that the pressure at the outflow end of the lymphatic was zero. After we determined the lymph flow with zero outflow pressure, we raised the cannula so that outflow pressure was equal to the actual venous pressure. We quantitated the effect of venous pressure on lymph flow rate by comparing the flow rate with outflow pressure = Pv to the flow rate with zero out low pressure. At baseline, Pv = 5.0 +/- 2.5 (SD) cmH2O and we found no difference in the two lymph flow rates. Pacing caused Pv and both lymph flow rates to increase significantly. However for Pv < 15 cmH2O, we found little difference in the two lymph flow rates. Thus increases in Pv to 15 cmH2O at the outflow to the lymphatics had little effect on lymph flow. By comparison, Pv > 15 cmH2O slowed lymph flow by 55 +/- 29% relative to the lymph flow rate with zero outflow pressure. Thus Pv values > 15 cmH2O interfere with lymph flow from the sheep caudal mediastinal lymph node.

Animals↗
PubMed1997

An update on supported employment for people with severe mental illness.

OBJECTIVE: This review examines the effectiveness of supported employment for people with severe mental illness. METHODS: A comprehensive search was made for quantitative studies, primarily in the published literature. RESULTS: Seven descriptive studies, three surveys, one quasi-experimental study, and six experimental studies were found. All studies suggested significant gains in obtaining employment for persons enrolled in supported employment programs. In experimental studies, a mean of 58 percent of clients in supported employment programs achieved competitive employment, compared with 21 percent for control subjects, who typically received traditional vocational services. Employment outcomes relating to time employed and employment earnings also favored clients in supported employment over control subjects. No evidence was found that supported employment led to stress levels precipitating higher rehospitalization rates. Two features of many supported employment programs have the most empirical support: integration of mental health and vocational services within a single service team and the avoidance of preplacement training. Two other widely held principles-ongoing support and attention to client preferences-have not been systematically evaluated. CONCLUSIONS: Supported employment appears to be a promising approach for people with severe mental illness, but more studies are needed, with close attention to program implementation and long-term follow-up.

Employment↗
PubMed1997

Housing status among formerly homeless dually diagnosed adults.

OBJECTIVE: Residential outcomes of homeless adults with severe mental illness and a substance use disorder were studied over 18 months during which participants received integrated dual diagnosis services and housing supports based on a continuum model. METHODS: Interviews with 158 participants at baseline and at six-, 12-, and 18-month follow-ups assessed housing status, residential history, substance abuse and progress toward recovery, psychiatric symptoms, and quality of life. Complete data were available for 122 participants. If participants lived continuously in high-quality housing with no housing loss or nights of homelessness during the final six months of the study, they were classified as having stable housing. RESULTS: Of the 122 participants for whom complete data were available, 64 (52 percent) achieved stable housing. Most participants who achieved stable housing first entered staffed and supervised housing and then moved to independent arrangements by the end of the study. Stable housing during the final evaluation period was associated with lower substance use, greater progress toward substance abuse recovery, and higher quality of life. Final housing status was not predicted by baseline variables but was predicted by progress toward recovery during months 0 to 6 and 6 to 12 and by less severe drug use during months 6 to 12. Participants who abused no illicit drugs during months 6 to 12 were almost three times as likely to achieve stable housing as those who abused illicit drugs. CONCLUSIONS: Housing stability is strongly mediated by substance abuse and progress toward recovery. Nevertheless, when formerly homeless persons with dual diagnoses are provided integrated dual diagnosis treatment, they can gradually achieve stable housing.

Adult↗
PubMed1996

The role of self-help programs in the rehabilitation of persons with severe mental illness and substance use disorders.

Substance abuse treatment programs in the United States frequently incorporate self-help approaches, but little is known about the use of self-help groups by individuals with dual disorders. This paper brings together several current studies on the role of self-help programs in treating substance use disorders among individuals with severe mental illness. These studies indicate that only a minority of individuals with dual disorders become closely linked to self-help. Psychiatric diagnosis and possibly social skills are correlates of participation. Dually disorders consumers often experience the use of 12-step philosophy and jargon by mental health professionals as alienating and unempathic. The authors propose suggestions for incorporating self-help approaches into the comprehensive community care of individuals with dual disorders.

Alcoholism↗
PubMed1996

New directions for treatment research on sequelae of sexual abuse in persons with severe mental illness.

Sexual abuse in childhood is increasingly recognized as an important etiologic component in a number of psychiatric disorders. One-quarter to one-third of all female children suffer sexual abuse before their eighteenth birthday, and at least one half of women with severe mental illness acknowledge such events. An even higher percentage of a particularly vulnerable group, dually diagnosed homeless women, appear to have a premorbid history of childhood victimization. In this paper, we review the emergent literature on childhood abuse, its sequelae and treatment; and discuss the implications of these data for the development of new approaches to trauma recovery in people with severe mental illness.

Adult↗
PubMed1996

The New Hampshire study of supported employment for people with severe mental illness.

This study compared supported employment services in 2 contrasting programs: (a) Group Skills Training, a professional rehabilitation agency outside of the mental health center that provided pre-employment skills training and support in obtaining and maintaining jobs, or (b) the Individual Placement and Support (IPS) model, which integrated clinical and vocational services within the mental health center. People with severe mental disorders who expressed interest in competitive employment (N = 143) were randomly assigned to 1 of these 2 programs. Results showed that clients in the IPS program were more likely to be competitively employed throughout most of the 18-month follow-up. Among those who obtained jobs, there were few group differences, although workers in the IPS program did work more total hours and earn more total wages during the 18-month follow-up. There were no group differences on nonvocational outcomes.

Adult↗
PubMed1996

Reversing a history of unmet needs: approaches to care for persons with co-occurring addictive and mental disorders.

Individuals with co-occurring addictive and mental disorders are particularly vulnerable to negative outcomes. Historically, they have been treated either in mental health or addiction service settings and sometimes excluded from receiving any services at all. This article presents an overview of the prevalence and clinical correlates of co-occurring disorders, and of the historical development of separate care systems for mental and addictive disorders. The articles that follow address future treatment and service system development.

Behavior, Addictive↗
PubMed1996

The course, treatment, and outcome of substance disorder in persons with severe mental illness.

Individuals with co-occurring substance abuse and severe mental illness are particularly vulnerable to negative outcomes. This paper reviews findings on the longitudinal course of dual disorders in traditional treatment systems, which provide separate mental health and substance-abuse programs; describes the movement toward programs that integrate both types of treatment at the clinical level; reviews evidence related to outcomes in integrated treatment programs; and discusses health-care policy changes that would encourage effective treatments.

Humans↗
PubMed1996

Lymphatic pump function curves in awake sheep.

We determined the relationship between flow rate and inflow pressure for intestinal lymphatic vessels in six sheep. First we anesthetized the sheep and cannulated both ends of a 6- to 10-cm-long segment of intestinal lymphatic. We allowed the sheep to recover from the anesthesia for 2-24 h. To determine the flow rate-inflow pressure relationship, we recorded the inflow pressure and infused Ringer solution into the lymphatic at rates from 34 to 510 microliters/min. The flow rate-pressure relationship was not linear and it had two regions. For flow rates less than approximately 150 microliters/min, inflow pressure was greater than outflow pressure. Thus the lymphatic pumped fluid against a pressure gradient. For flow rates > 150 microliters/min, inflow pressure was greater than outflow pressure, and we attributed most of the flow to the favorable inflow-outflow pressure gradient (passive flow). When we used verapamil to inhibit lymphatic pumping, we found no flow for inflow pressure less than outflow pressure, and flow increased linearly for inflow pressure greater than outflow pressure. Our data for actively pumping lymphatic vessels are consistent with the flow vs. pressure relationships derived from mathematical models of the lymphatic pump. Furthermore, our data with verapamil confirm that active lymphatic pumping was responsible for the nonlinear flow vs. pressure relationship for the lymphatic vessels.

Animals↗
PubMed1996

Day treatment versus supported employment for persons with severe mental illness: a replication study.

Outcomes for 112 clients with severe mental disorders in a community mental health center that converted its rehabilitative day treatment program to a supported employment program were assessed during the year after the program conversion. The study replicated a previous study in showing that the rate of competitive employment improved, especially among clients who had formerly attended the day treatment program, without evidence of adverse effects.

Adult↗
PubMed1996

Job preferences of clients with severe psychiatric disorders participating in supported employment programs.

OBJECTIVE: The job preferences of adults with severe mental illness who were participating in supported employment programs were examined. METHODS: Data were collected on job preferences, attainment of competitive employment, job satisfaction, and job tenure of 135 adults who participated in two supported employment programs in New Hampshire. Data obtained at baseline and at six-month follow-up were analyzed. RESULTS: When the clients entered the supported employment programs, 81 percent expressed job preferences, and their preferences tended to be realistic and stable. People who obtained employment in preferred areas were more satisfied with their jobs and remained in their jobs twice as long as those who worked in nonpreferred areas. Clients were more likely to develop a new job preference or to change their preference if they participated in a program that emphasized rapid job search than if they participated in a prevocational skills training program. They were also more likely to develop a preference or change their preference if they obtained a competitive job. CONCLUSIONS: Helping people with severe mental illness obtain competitive jobs that correspond with their explicit job preferences increases job satisfaction and tenure. Job preferences are more likely to develop or change through searching for a job or working at a job than through prevocational training.

Adult↗
PubMed1996

Renal lymphatic function following venous pressure elevation.

The renal lymphatic system plays an important role in removing excess fluid from the kidneys. Unfortunately, the factors influencing lymphatic flow are difficult to measure. We used a simple model to represent renal lymphatics as a single pressure source (PL) pushing lymph through a single resistance (RL). In anesthetized dogs, we cannulated renal lymphatics and measured lymph flow rate (QL) as we varied pressure (PO) at the outflow end of the lymphatics. There was no significant change in QL as we increased PO from -5 to 0 cm H2O. In other words, there was a plateau in the QL vs. PO relationship. At higher PO's, QL decreased linearly with increases in PO. From this linear relationship, we calculated RL as -delta PO/ delta QL and we took PL as the PO at which QL = 0 microliter/min. At baseline, RL = 0.34 +/- 0.14 (SD) cm H2O.min/microliter and PL = 8.2 +/- 4.4 cm H2O. When we increased renal venous pressure (PV) from baseline (3.5 +/- 3.0 cm H2O), the plateau in the QL vs. PO relationship extended to higher PO's, RL decreased, and PL increased. Renal interstitial fluid volume and interstitial pressure increased following elevation of PV. The extension of the QL vs. PO plateau with increasing PV suggests that renal interstitial pressure may partially collapse intrarenal collecting lymphatics which may compromise lymph flow.

Animals↗