Stereotactic radiosurgical treatment of brain metastases

In a series of 33 patients with reasonably controlled primary cancers, stereotactic radiosurgery was used to treat 52 brain metastases. After a mean radiological follow-up time of 5.5 months, six lesions (12%) had stabilized in size, 26 (50%) were significantly reduced, and 15 (29%) had disappeared. One large melanoma metastasis progressed relentlessly despite treatment. Five lesions (9%) had decreased in size slightly before enlarging. In two of these lesions, biopsy revealed only necrosis. In almost all cases, treatment was associated with decreased peritumoral edema. However, a group of patients with large metastases and extensive prior brain irradiation has been identified in whom prolonged symptomatic cerebral edema poses a problem. It is concluded that radiosurgery is a viable alternative to surgical resection for some cases of brain metastasis.

The Health of the Public Program at the University of Washington: a new role for academic medical centers

The University of Washington Health of the Public Program has convened a consortium composed of the region's academic medical center, the two largest managed care plans in Washington, and representatives of the state's major private and public purchasers of health care. The consortium's purpose is to test the feasibility of collaboratively collecting cross-system data, assessing variations in practice, and implementing site-specific interventions to improve the management of common illnesses and encourage preventive care. Changes under way in the ambulatory training environment and in the undergraduate curriculum as a result of the consortium's initial efforts are described. In today's climate of cost consciousness and concerns about quality, academic medical centers can play an important role in helping to improve community-wide outcomes of care.

Use of a preferred provider plan by employees of the City of Seattle

Little is known about the use of services in a preferred provider organization (PPO). We studied a preferred provider arrangement between Pacific Medical Center and employees of the City of Seattle. In the second 12 months of this program 8,529 subjects submitted at least one claim; of these, only 420 (4.9%) ever used the preferred provider. Those who used the PPO at least once differed significantly from those who never used it on age, sex, employee/dependent status, and utilization in the previous year. Outpatient and total charges were higher for PPO users than for nonusers before and after control for those characteristics. Those who used the PPO exclusively were similar to those who never used it. People who used both the PPO and other providers were at higher risk for use of services, and had much higher overall utilization, with or without control for other variables. No differences were found between people who obtained only a small proportion of their services at the PPO and those who had most (but not all) of their use at the PPO. Many of these findings can be explained by a self-selection model. It is important for research on PPOs to have an independent manner of assessing who is a PPO user.

Interferon suppresses sympathetic neuronal cell death caused by nerve growth factor deprivation

Cultured rat sympathetic neurons die within 48 h after being deprived of nerve growth factor. Addition of interferons (IFN-alpha/beta or IFN-gamma) prevented the cell death in a dose-dependent manner. Upon longer periods of nerve growth factor deprivation, IFNs failed to maintain survival. Thus, IFNs retarded neuronal death, but did not prevent it. Ligand binding, autoradiography, and cross-linking experiments demonstrated the presence of specific IFN-gamma receptors on sympathetic neurons similar to those seen on other cell types. The possible relationships of the death-suppressing actions of IFNs are compared to the mechanisms of the antiviral or antiproliferative actions of IFNs.

Cytosine arabinoside kills postmitotic neurons in a fashion resembling trophic factor deprivation: evidence that a deoxycytidine-dependent process may be required for nerve growth factor signal transduction

Cytosine arabinoside (AraC) is a pyrimidine antimetabolite that kills proliferating cells by inhibiting DNA synthesis. In this paper we report that AraC kills postmitotic rat sympathetic neurons in a fashion similar to the neuronal death that follows nerve growth factor (NGF) deprivation. Postmitotic rat sympathetic neurons were cultured for 1 week in the presence of NGF and then treated with AraC, still in the presence of NGF. AraC killed neurons after 4 d with an EC50 of 50 microns. The morphological and temporal characteristics of neuronal death that began around 3 d after addition of AraC were indistinguishable from those observed beginning 24 hr after NGF deprivation. Death caused by AraC was prevented by the same agents that prevent the death of NGF-deprived neurons, which included inhibitors of RNA and protein synthesis, a cAMP analog, and depolarizing concentrations of KCl. In contrast, neuronal death caused by ultraviolet irradiation, ricin toxin, and a variety of other toxic insults did not share these morphological, biochemical, or temporal characteristics. Other antimitotic drugs, including adenine arabinoside, thymine arabinoside, fluorodeoxyuridine, hydroxyurea, and aphidicolin, did not kill neurons. AraC caused neurons to behave as if deprived of NGF by interfering with deoxycytidine (dC) metabolism distinct from DNA biosynthesis. dC entirely prevented the neurotoxicity of AraC, even when present at a concentration 1000-fold less than that of AraC. Other deoxynucleosides, and cytidine, did not prevent AraC neurotoxicity. dC could not, however, substitute for NGF and thus is unlikely to be a direct mediator of NGF action. It is hypothesized that dC may participate in a pathway, distinct from DNA synthesis, that is necessary for neurons to respond to exogenous trophic factors.

Effect of a gatekeeper plan on health services use and charges: a randomized trial

A randomized trial was conducted to determine the effectiveness of a health care plan which uses physicians as gatekeepers to control health services use and charges. New enrollees in United Healthcare (UHC), an independent practice association, were randomly assigned to the standard UHC plan requiring a gatekeeper, or to an alternate plan with equal benefits but without a gatekeeper. Individuals in both plans were similar in demographic characteristics, perceived health status, and other health insurance coverage. The gatekeeper plan had 6 percent lower total charges per enrollee than the plan without a gatekeeper. There were minor differences in hospital use and charges. Ambulatory charges were $21 lower per person per year in the plan with a gatekeeper (95% CI = -39.9, -2.1) and these were due to .3 fewer visits to specialists (95% CI = -0.50, -0.10). We conclude that a health plan which incorporates incentives and penalties for physicians to act as gatekeepers can reduce the cost of ambulatory services by limiting specialist visits.

Why do neurons die when deprived of trophic factor?

In this commentary we present circumstantial evidence which supports the hypothesis that neuronal death produced by trophic factor deprivation (i.e., axotomy, target loss, etc.) is not a passive process resulting from a loss of trophic stimulation. Rather, we suggest that it is due to the activation of an endogenous "suicide program" requiring mRNA and protein synthesis. The possible mechanistic relationship of neuronal death to death of other cell types, both in the developing and adult organism, is discussed. If this hypothesis of active death is true, then loss of transcriptional control of this program may be involved in neuronal attrition in aging or neurodegenerative disease.

Role of Ca2+ channels in the ability of membrane depolarization to prevent neuronal death induced by trophic-factor deprivation: evidence that levels of internal Ca2+ determine nerve growth factor dependence of sympathetic ganglion cells

Sympathetic neurons depend on nerve growth factor (NGF) for their survival both in vivo and in vitro; these cells die upon acute deprivation of NGF. We studied the effects of agents that cause membrane depolarization on neuronal survival after NGF deprivation. High-K+ medium (greater than or equal to 33 mM) prevented cell death; the effect of K+ was dose-dependent (EC50 = 21 mM). The protection by high K+ was abolished either by withdrawal of extracellular Ca2+ or by preloading the cells with a Ca2+ chelator. The involvement of Ca2+ flux across membranes in high-K+ saving of NGF-deprived neurons was also supported by experiments using Ca2+-channel antagonists and agonists. The Ca2+ antagonists nimodipine and nifedipine effectively blocked the survival-promoting effect of high K+. The Ca2+ agonists Bay K 8644 and (S)-202-791 did not by themselves save neurons from NGF deprivation but did strongly augment the effect of high K+; EC50 was shifted from 21 mM to 13 mM. These data suggest that dihydropyridine-sensitive L-type Ca2+ channels play a major role in the high-K+ saving. The depolarizing agents choline (EC50 = 1 mM) and carbamoylcholine (EC50 = 1 microM), acting through nicotinic cholinergic receptors, also rescued NGF-deprived neurons. The saving effect of nicotinic agonists was not blocked by withdrawal of extracellular Ca2+ but was counteracted by a chelator of intracellular Ca2+, suggesting the possible involvement of Ca2+ release from internal stores. Based on these findings we propose a "Ca2+ set-point hypothesis" for the degree of trophic-factor dependence of sympathetic neurons in vitro.

Inhibitors of protein synthesis and RNA synthesis prevent neuronal death caused by nerve growth factor deprivation

We have developed an experimental paradigm to study the mechanism by which nerve growth factor (NGF) allows the survival of sympathetic neurons. Dissociated sympathetic neurons from embryonic day-21 rats were grown in vitro for 7 d in the presence of NGF. Neurons were then deprived of trophic support by adding anti-NGF antiserum, causing them to die between 24 and 48 h later. Ultrastructural changes included disruption of neurites, followed by cell body changes characterized by an accumulation of lipid droplets, changes in the nuclear membrane, and dilation of the rough endoplasmic reticulum. No primary alterations of mitochondria or lysosomes were observed. The death of NGF-deprived neurons was characterized biochemically by assessing [35S]methionine incorporation into TCA precipitable protein and by measuring the release of the cytosolic enzyme adenylate kinase into the culture medium. Methionine incorporation began to decrease approximately 18 h post-deprivation and was maximally depressed by 36 h. Adenylate kinase began to appear in the culture medium approximately 30 h after deprivation, reaching a maximum by 54 h. The death of NGF-deprived neurons was entirely prevented by inhibiting protein or RNA synthesis. Cycloheximide, puromycin, anisomycin, actinomycin-D, and dichlorobenzimidazole riboside all prevented neuronal death subsequent to NGF deprivation as assessed by the above morphologic and biochemical criteria. The fact that sympathetic neurons must synthesize protein and RNA to die when deprived of NGF indicates that NGF, and presumably other neurotrophic factors, maintains neuronal survival by suppressing an endogenous, active death program.

Use of ambulatory health care services in a preferred provider organization

The organization of the delivery of health care can have significant cost-saving implications, but few of the available studies have made adequate comparisons of costs across plans. Furthermore, new organizational types such as independent practice associations and preferred provider organizations have not yet been studied in detail. This paper examines ambulatory utilization in a preferred provider organization (PPO) for Uniformed Services beneficiaries at Pacific Medical Center (PMC) in Seattle. The utilization in the PPO is compared with the results of a recently reported study of three other organizationally different Seattle plans: a Blue Cross/Blue Shield plan (BC), a closed-panel health maintenance organization (HMO), and an independent practice association (IPA). The PPO was similar to the IPA and the HMO in having a high percent of patients with any ambulatory use and had standardized ambulatory costs per user which were lower than BC but higher than the HMO. Thus, this particular type of PPO may have cost-saving features, particularly because the Uniformed Services population is known to use more health services than the general population. Methodological issues for future utilization research across organizations are also discussed.

Factors affecting choice of health care plans

The research reported here examined the factors which affected the decision to remain with either Blue Cross of Washington and Alaska or Group Health Cooperative of Puget Sound, or to change to an independent practice association (IPA) in which the primary care physicians control all care. The natural setting allowed examination of the characteristics of families with experience in structurally different plans; a decision not influenced by premium differentials; the importance of the role of usual provider; and a family-based decision using multivariate techniques. An expected utility model implied that factors affecting preferences included future need for medical care; access to care; financial resources to meet the need for care; and previous level of experience with plan and provider. Analysis of interview and medical record abstract data from 1,497 families revealed the importance of maintaining a satisfactory relationship with the usual sources of care in the decision to change plans. Adverse selection into the new IPA as measured by health status and previous utilization of medical services was not noted.

Factors related to the use of ambulatory mental health services in three provider plans

The use of ambulatory mental health (MH) services by adults was studied in three provider plans: Blue Cross (BC), Group Health Cooperative (GHC) and United Healthcare (UHC), an experimental new plan in which a patient's primary care physician managed all of his care. Approximately 8.3% of the enrollees in each plan had some MH use in the 18 months of the study. We studied correlates of MH use (yes/no). Sex was not a significant predictor of MH use. In general, worse health and lower socioeconomic status (SES) were correlated with having at least one MH visit, but better health and higher SES were correlated with a higher quantity of use for those who had some MH use. The three insurance plans did not differ significantly in the proportion of people who had any MH services, but BC users of MH services had 2-3 times more MH visits and higher costs than GHC and UHC users. This suggests that the reliance on primary care providers in UHC and GHC may have changed the nature of MH care as compared to Blue Cross. The effects of income, MH need and symptom sensitivity on MH use were different among the three plans.

Use of outpatient somatic health services by patients who use or need mental health services in three provider plans

A major topic in mental health (MH) research addresses the problem that patients who use mental health services have inappropriately high levels of somatic use, and examines whether provision of mental health services can decrease the inappropriate use (the so-called offset effect). However, the research showing higher somatic use by mental health patients has usually been unable to control for the patients' health status, or for their mental health status. In this paper we examine use of somatic health services by enrollees in three provider plans as a function of both mental health use and mental health need. In two of the provider plans (an HMO and a prepaid independent practice association), MH users used significantly more outpatient somatic services than non-MH patients, after control for age and sex, and after control for the number of chronic conditions they had. People with MH need, however, did not use significantly more MH services than those without MH need. In the third plan, a Blue Cross/Blue Shield type of plan, results were different; MH users did not have significantly higher somatic utilization after control for chronic conditions, and those with MH need did have significantly higher somatic utilization after control for age and sex, but not after control for the number of chronic conditions. These results suggest that the form of inappropriate use of outpatient somatic services, and the nature of an offset effect, may be specific to the type of insurance provided.

Out-of-plan use by Medicare enrollees in a risk-sharing health maintenance organization

In this study, we analyzed the cost and volume effects of a waiver that eliminated lock-in restrictions on out-of-plan use in a health maintenance organization (HMO) with a Medicare risk-sharing contract. We compared out-of-plan cost and number of claims during a 15-month base line period when the lock-in was in effect, with a 24-month waiver period when the lock-in was removed. The results demonstrate that average per capita cost and claims increased significantly for both Medicare Part A (hospital insurance) and Part B (supplementary medical insurance) out-of-plan services during the waiver. Self-referred out-of-plan use normally prohibited by lock-in, accounted for 20 percent of all out-of-plan costs during the waiver and 57 percent of the increase in out-of-plan costs from the lock-in to the waiver. The combination of risk-sharing and lock-in provisions holds promise as a method for reducing expenditures for the Medicare program.

Ambulatory mental health services utilization in three provider plans

This article examines the use of mental health services in three insurance plans: Blue Cross (BC), a health maintenance organization (HMO), and an independent practice association (IPA) in which the primary care physician was to manage all care for an individual. Approximately 7.3% of the enrollees in all three plans used some mental health care in the 18-month study period. The percent of enrollees with mental health utilization was lower in BC than in the other two plans, but the total quantity of mental health care use per enrollee and per user was much higher in BC than in the HMO and the IPA. Use was highest in the 19-44-year-old age group, and there were no significant differences between men and women in use of mental health services. There were substantial differences by race in all three plans: white persons were more likely to use any mental health care and had more visits than nonwhite persons after seeking mental health use. A similar study was conducted in the early 1970s on a poverty-level population enrolled in BC and the HMO. The findings of this study are similar, except that in the low-income study mental health care use was lower, and males used less mental health care than females. These differences might be attributable to the difference in enrollees' socioeconomic status in the two studies or to the increasing acceptability of mental health care utilization, particularly for males.

Use of ambulatory care services in three provider plans: interactions between patient characteristics and plans

A previous study of low-income enrollees in a closed-panel health maintenance organization (HMO) and a Blue Cross/Blue Shield (BC/BS) plan showed that the effect on the use of health services of the age, sex, health status, previous health care use, race, and family size of the enrollees was different in the two plans. We have replicated this study using the same two provider plans but studying a different group of white collar, middle class enrollees. A third plan, an experimental independent practice association (IPA), was also available for analysis. Utilization was defined as use (yes/no) and the quantity of use for those who used services (in standardized dollars). Significant interactions were detected between plan and all of the independent variables but race. The use of services in the HMO was least affected by enrollees' characteristics (age, sex, race, health status, prior use, family size) and use was most sensitive to patient characteristics in BC. In some respects, the IPA was more like the HMO and in other respects more like the BC/BS plan.

Epizootic of parainfluenza-3 virus infection in gibbons

A laboratory-housed breeding colony of white-handed gibbons (Hylobates lar) experienced an epizootic of upper respiratory tract disease characterized by lethargy, anorexia, coughing, and serous rhinorrhea. Signs were more severe in adults than in offspring, and all animals recovered without complications. Base-line, acute, and convalescent sera from the most severely affected gibbons were tested for antibodies against a wide spectrum of infectious agents. For personnel known to have had contact with the gibbons, testing for the same agents was done on base-line sera and sera obtained at the same time as the acute and convalescent sera were obtained from the gibbons. Rising titers against parainfluenza-3 virus were detected in 6 of 7 gibbons tested. An increase in titer was not seen in the sera of personnel.

Serological investigation of an outbreak of simian varicella in Erythrocebus patas monkeys

An epizootic of simian varicella occurring in a colony of Erythrocebus patas monkeys was studied serologically by using radioimmunoassay and neutralization tests against (i) a virus strain isolated from an animal that died during the epizootic, (ii) a simian varicella virus strain from an earlier outbreak of simian varicella-like disease at another facility, and (iii) human varicella-zoster virus. Serological tests detected more cases of infection among the animals exposed to virus during the epizootic than were evidenced by clinical findings; only 6 of the 26 animals with seroconversion developed a rash. Good correlation was seen between antibody responses demonstrated by radioimmunoassay and by the neutralization tests. Specificity of the radioimmunoassay was evidenced by the complete agreement with neutralization results for 17 animals which failed to show an antibody response over the course of the outbreak and were assumed not to have been infected. Thus radioimmunoassay is a reliable, rapid, and relatively economical method which could be used for serological screening of primates entering experimental colonies to identify those which might be potential sources of outbreaks through activation of latent simian varicella virus infection. Close correlation was seen between antibody responses to the virus strain from the current outbreak and the one from another epizootic, indicating that the two outbreaks were caused by antigenically similar viruses. Animals showing neutralizing antibody responses to the simian varicella viruses also showed responses to human varicella-zoster virus, which further substantiates the close antigenic relationship between human and simian varicella viruses.

Interferon prophylaxis against simian varicella in Erythrocebus patas monkeys

Erythrocebus patas monkeys were given placebo or human leukocyte interferon (5 x 10(5) units/kg of body weight per day im) for five days during an epizootic of simian varicella. During the 14 days beginning with the first day of treatment, the attack rate for simian varicella was 14.3% (two of 14) among interferon recipients compared to 70% (nine of 13) among placebo recipients (P less than 0.025). Excluding animals with antibody to simian varicella when the study began, 18% (two) of 11 interferon recipients had symptoms of infection compared to 80% (nine) of 11 placebo recipients (P less than 0.025). The epizootic began in a room housing male animals. The incidence of infection in male placebo recipients was 100% (seven of seven) compared to 14% (one of seven) in male interferon recipients (P less than 0.01). The efficacy of interferon prophylaxis in the simian varicella model supports its continued evaluation for the management of human varicella in high-risk patients.

Cost containment through risk-sharing by primary care physicians: a history of the development of United Healthcare

A new type of independent practice association has been organized to encourage primary care physicians in private practice to become coordinators and financial managers for their patients' medical care. Each patient chooses one internist, family or general physician, or pediatrician and must be referred by that physician for all specialized care. The primary care physician authorizes payment from his/her own account for hospital and referral care provided to patients. He or she shares any deficit or surplus remaining at the end of the year. This is a background paper detailing the history of development and specific features contained in this new concept of putting the physician in charge and "at risk" for the costs of medical care to his/her patients. The plan has been operating in northern California, Washington, and Utah and has 40,000 members and 750 participating physicians. This historical background paper is part of a large project--State Employees' Insurance Benefits Utilization Study (SEIBUS) being done by the University of Washington School of Public Health to evaluate use and costs of medical care under this innovative plan.

Prevalence of prior hysterectomy in the Seattle-Tacoma area

Hysterectomy is the most common major surgical procedure performed in the United States. The frequency of hysterectomy among women in the general population is of interest because it affects the population at risk for uterine diseases and because the procedure itself carries significant personal and socioeconomic consequences. We studied factors related to the occurrence of hysterectomy by interviewing a representative sample of women ages 35-74 (n= 1087) in two urban Washington counties during 1976-1977.One-third of the women studied had had a hysterectomy. Later birth cohorts were at higher risk. The ageadjusted prevalence of prior hysterectomy was negatively associated with education and age at first childbirth; it was positively associated with parity, history of irregular menses, and history of a variety of other health conditions. Contrary to expectation, income was negatively associated with hysterectomy rates in one county and showed no association in the other. Part of the income effect was due to confounding by age at first childbirth, which was a surprisingly strong predictive factor. WE CONCLUDE THAT: 1) despite economic predictions based on the discretionary nature of the procedure, hysterectomies are not necessarily more common among high-income women; 2) age at first childbirth may be a more important risk factor for uterine disease than previously thought; and 3) estimates of hysterectomy frequency based on clinic populations may be misleading. (Am J Public Health 70:40-47, 1980.)