An organizational field approach to resource environments in healthcare: comparing entries of hospitals and home health agencies in the San Francisco Bay region.

OBJECTIVE: To draw together insights from three perspectives (health economics, organizational ecology, and institutional theory) in order to clarify the factors that influence entries of providers into healthcare markets. A model centered on the concept of an organizational field is advanced as the level of analysis best suited to examining the assortment and interdependence of organizational populations and the institutional forces that shape this co-evolution. In particular, the model argues that: (1) different populations of healthcare providers partition fiscal, geographic, and demographic resource environments in order to ameliorate competition and introduce service complementarities; and (2) competitive barriers to entry within populations of providers vary systematically with regulatory regimens. DATA SOURCES: County-level entries of hospitals and home health agencies in the San Francisco Bay Area using data from the American Hospital Association (1945-1991) and California's Office of Statewide Health Planning and Development (1976-1991). Characteristics of the resource environment are derived from the Area Resource File (ARF) and selected government censuses. METHODS OF ANALYSIS: A comparative design is applied to contrast influences on hospital and home health agency entries during the post-World War II period. Empirical estimates are obtained using Poisson and negative binomial regression models. RESULTS: Hospital and HHA markets are partitioned primarily by the age and education of consumers and, to a lesser extent, by urbanization levels and public funding expenditures. Such resource partitioning allows independent HHAs to exist comfortably in concentrated hospital markets. For both hospitals and HHAs, the barriers to entry once generated by oligopolistic concentration have declined noticeably with the market-oriented reforms of the past 15 years. CONCLUSION: A field-level perspective demonstrates that characteristics of local resource environments interact with interdependencies of provider populations and broader regulatory regimes to affect significantly the types of provider organizations likely to enter a given healthcare market.     

Influence of high voltage pulsed current on edema formation following impact injury in rats.

High voltage pulsed current (HVPC) has been shown to be effective in curbing posttraumatic edema formation in frogs. The purpose of this study was to establish the utility of HVPC in controlling edema formation in a mammalian model. Both feet of 20 anesthetized rats were traumatized following initial determination of hind-limb volumes. Four 30-minute cathodal HVPC treatments at 120 pulses per second and 90% of visible motor threshold interspersed with 30-minute rest periods were applied to one randomly selected hind limb of each rat via the immersion technique. The other hind limb served as a control. Limb volumes were measured after each treatment and rest period. All data were expressed as changes from pretrauma limb volumes in milliliters per kilogram of body weight; these data were analyzed by repeated-measures analyses of variance and post hoc paired t tests. Volumes of untreated limbs were significantly greater than volumes of treated limbs after the second treatment. Evidence of significant treatment effects in frogs, and now rats, provides a compelling rationale for initiating trials of efficacy of cathodal HVPC in inhibiting acute edema formation in humans.     

Inactivation of quercetin mutagenicity

Combinations of oxygen and alkaline pH were found to inactivate irreversibly the mutagenicity of quercetin towards Salmonella typhimurium strain TA98. Exposure time, quercetin concentration and polyphenol oxidase were also important variables determining the extent of quercetin inactivation. Temperature had a relatively weak influence on the extent of inactivation. The metal salts, ferrous, ferric and copper sulphates also brought about inactivation but this effect was partially reversed when the pH of the incubation medium was reduced from 7 to 2. Ferric sulphate had a much smaller effect than did the ferrous salt except in the presence of tyrosinase and oxygen at pH 7. Zinc sulphate impaired quercetin mutagenicity only very slightly in the presence of tyrosinase and oxygen. When an oxygen-saturated solution of quercetin was exposed to tyrosinase at various pH values, the ultraviolet absorption maximum of quercetin near 370 nm decreased to an extent that correlated with the mutagenicity of quercetin under those conditions.     

Living with dizziness: an explorative study

A qualitative study was conducted for the purpose of exploring how patients with dizziness manage their daily living. Ten patients with history of dizziness were recruited from the out-patient clinic, Department of Audiology, in a hospital in Stockholm. Collection and analysis of data were inspired by the method of grounded theory. Four themes were developed that described the experience of living with dizziness: vulnerable reactions, affirmation and non-affirmation, finding ways to carry on daily living, and expressing the need for health care support. These themes seem to conceptualize these patients' difficulties and needs in relationship to living with dizziness and, given the small sample, have implications for nursing practice and provide a framework for a broader study.     

Insulinoma. Results of surgical treatment

The insulinoma is the most common pancreas tumour with endocrine activity, with more than 2,000 cases being described in the literature worldwide. The first successful extirpation was performed by Graham in 1928. Clinical appearance is characterized by severe paroxysmal hypoglycaemia together with inadequately increased serum insulin levels. Surgery is indicated in such situations because of limited effectiveness of medicamentous therapy. Surgical approach and long-time results are discussed in this paper, with reference being made to 13 cases of the authors.     

Thermal response of intravascular and rectal tissue to temperature changes and chemical conditions in the rumen of sheep

1. Experiments were conducted with two wether sheep which were fitted with rumen cannulae and chronically implanted intravascular thermocouples. An attempt was made to study the thermal response of intravascular and rectal tissue to temperature changes and chemical conditions in the rumen.2. When ice or hot water were placed in the rumen there was an immediate fall or rise in the intravascular temperature accompanied by a similar change in rectal temperature. The intravascular temperatures returned to their precooling or preheating level of 40 degrees C within 130 min, the rectal temperatures required 6-8 hr to return to their pretreatment values.3. When 0.5 M acetic acid was infused into the rumen there was a marked rise in the intravascular temperature, over and above the diurnal rhythm but not in rectal temperatures. Infusion of mixtures of acetic plus propionic or acetic plus n-butyric acids caused an intravascular temperature rise on feeding within the range of the diurnal pattern. In fasted animals, infusions of volatile fatty acids resulted in no rise in intravascular temperature.     

A family practice approach to the pediatric prenatal visit

Although recommended by many authorities, prenatal pediatric visits are not regularly scheduled. Thirty to 45 minutes should be allowed for review of the family background, obstetric history and psychosocial factors. The discussion should also include hospital concerns, as well as the practical and emotional aspects of returning home with a newborn. In addition, issues such as sleeping arrangements, safety, diapers and feeding should be addressed.