Modulation of cell firing in the nucleus accumbens

Pennartz et al. have proposed that functions of the nucleus accumbens (NA) are subserved by the activity of ensembles of neurons rather than by an overall neuronal activation. Indeed, the NA is a site of convergence for a large number of inputs from limbic structures that may modulate the flow of prefrontal cortical information and contribute to defining such ensembles, as exemplified in the ability of hippocampal input to gate cortical throughput in the nucleus accumbens. NA neurons exhibit a bistable membrane potential, characterized by a very negative resting membrane potential (down state), periodically interrupted by plateau depolarizations (up state), during which the cells may fire in response to cortical inputs. A dynamic ensemble can be the result of a distributed set of neurons in their up state, determined by the moment-to-moment changes in the spatial distribution of hippocampal inputs responsible for transitions to the up state. Ensembles may change as an adaptation to the contextual information provided by the hippocampal input. Furthermore, for dynamic ensembles to be functionally relevant, the model calls for near synchronous transitions to the up state in a group of neurons. This can be accomplished by the cell-to-cell transfer of information via gap junctions, a mechanism that can allow for a transfer of slow electrical signals, including "up" events between coupled cells. Furthermore, gap junction permeability is tightly modulated by a number of factors, including levels of dopamine and nitric oxide, and cortical inputs, allowing for fine-tuning of this synchronization of up events. The continuous selection of such dynamic ensembles in the NA may be disputed in schizophrenia, resulting in an inappropriate level of activity of thalamocortical systems.

The impact of Medicaid managed care on community clinics in Sacramento County, California

OBJECTIVES

The purpose of this study was to determine the impact of countywide Medicaid managed care on service use at community clinics.

METHODS

Clinic use before and after introduction of Medicaid plans in one county was compared with that in a group of comparable counties without such plans.

RESULTS

There were significant declines of 40% to 45% in the volumes of Medicaid clients, encounters, and revenues at clinics with the introduction of Medicaid plans. Declines of 23% in uninsured clients and encounters did not differ significantly.

CONCLUSIONS

The introduction of Medicaid managed care with multiple commercial plans can have significant negative effects on nonprofit community clinics.

Head games. Hiring trends

The times demand executives who can deal well with doctors and handle the chaos of rapid change. And that's why your next job interview could include a personality test. "I can't supplement efficiencies in those areas with machinery or equipment or even training," says one recruiter. "A hospital can give you all the tools in the world, but the only one that counts is the one between your ears."

From whodunit to what happened

An amnesty on errors? A few hospitals are declaring one, finding that it actually helps reduce mistakes. "This is a very hard sell," acknowledges one nursing executive. "But once people trusted they wouldn't be disciplined for reporting mistakes, we were able to look at systems and solve problems."

Brain regions involved in articulation

BACKGROUND

The left inferior frontal gyrus (Broca's area) is generally believed to be critical for the motor act of speech. A lesion-based analysis has, however, shown that the left anterior insula is necessary for accurate articulation. We used functional imaging in normal people to show the neural systems involved in speech during different speech tasks.

METHODS

12 normal people underwent positron emission tomography with oxygen-15-labelled water as tracer. We measured cerebral activity while participants performed three different tasks: repetition of heard nouns at different rates; listening to single nouns at different rates; and anticipation of listening or repetition. We analysed the data with imaging software.

FINDINGS

Repetition of single words did not activate Broca's area but activity in three left-lateralised regions was seen: the anterior insula, a localised region in the lateral premotor cortex, and the posterior pallidum. The left anterior insula and lateral premotor cortex showed a conjunction of activity for hearing and articulation. In addition, articulation modulated the response to hearing words in the left dorsolateral temporal cortex, the physiological expression of the speaker's auditory attention being directed towards the stimuli and not his or her articulated responses.

INTERPRETATION

The formulation of an articulatory plan is a function of the left anterior insula and lateral premotor cortex and not of Broca's area. The left basal ganglia seem to be dominant for speech, although the axial muscles involved receive their motor output from both cerebral hemispheres.

Al wants more hair, less fat, and a better sex life ... and he wants his health plan to pay for it

Al wants a trimmer waistline. Hanna wants the surgery that will give her ears, which she was born without. Both think their HMOs should pay. Hanna and Al are at the limits of the emerging gray zone between medical need and medical want. It's a zone sure to become grayer, as medicine strays even further into the murkey region of lifestyle enhancement.

Melatonin for the masses. Antiaging entrepreneurs peddle therapies that promise to cheat the clock

The come-ons for a new wave of antiaging clinics may be over the top, but they speak to boomer anxieties about flagging energy levels and flabby midsections. And they just may be the next hot trend in health care.

The economics of febrile neutropenia: implications for the use of colony-stimulating factors

The occurrence of fever and neutropenia following cancer chemotherapy generally prompts hospitalisation for evaluation and treatment. Colony-stimulating factors (CSFs) have been shown to reduce the risk of febrile neutropenia (FN) and the need for hospitalisation in such patients. This study was undertaken to obtain estimates of the actual institutional costs associated with FN and the impact of these costs on threshold estimates for the appropriate use of CSFs. Total hospital expenditures for patients admitted with FN over a 2 year period were studied. A cost allocation function was utilised to allocate all direct costs for non-revenue-generating support centres to revenue-generating service centres as indirect costs. A cost accounting function was then utilised to allocate direct and indirect costs for each service centre to the charge code level. Two groups of patients were defined based on diagnostic codes to represent the spectrum of patients with FN. Total hospital costs were estimated and incorporated into a cost model for the use of CSFs. Variation in the total cost of hospitalisation for FN relates primarily to differences in the average length of stay. The daily cost of hospitalisation was comparable in the groups studied, averaging between US$1675 and US$1892. Incorporation of these cost estimates into the cost model yielded FN risk threshold projections for CSF use in the range of 20-25%. Preliminary studies suggest that incorporation of non-medical, indirect and intangible costs into the CSF decision models will further decrease FN risk threshold projections. Total hospitalisation cost estimates for managing patients with FN are greater than those previously reported, reducing projected FN risk thresholds for CSF use.

A performance indicator of psychosocial services in enhanced prenatal care of Medicaid-eligible women

OBJECTIVE

Psychosocial services for low-income pregnant women vary widely in practice, and validated indicators of effective performance are lacking. The study presented here aims to determine whether a measure of provider compliance with a psychosocial service delivery guideline is associated with improved birth outcomes and therefore meets an important validity criterion of a performance indicator.

METHODS

Data on psychosocial services delivered to 3467 pregnant women came from 27 sites certified by the California Department of Health Services to provide enhanced perinatal services to Medicaid-eligible women. Multivariate regression analyses were used to test the association of adequate service delivery according to a performance guideline with birth outcomes and the dependence of the association on the credentials of the provider and the type of practice setting.

RESULTS

Women who received at least one psychosocial assessment each trimester of care according to the guideline were half as likely as women with inadequate services to have a low birthweight (OR = 0.49; CI 0.34, 0.71) or preterm birth (OR = 0.53; CI 0.40, 0.72) outcome. The effect did not depend on the credentials of the provider or the practice setting type.

CONCLUSIONS

The indicator of the adequacy of psychosocial services according to a performance guideline appears to meet a fundamental criterion for a performance indicator, an association with improved outcomes. This indicator may be useful in monitoring performance of enhanced perinatal services for continuous quality improvement of services to low-income pregnant women.

Outcome states of colorectal cancer: identification and description using patient focus groups

OBJECTIVE

Utilities for the outcome states of colorectal cancer must be measured to evaluate the cost-utility of screening and surveillance strategies for this disease. We sought to identify these outcome states, define their associated areas of morbidity, and construct representative descriptions of them for use in a utilities assessment instrument.

METHODS

We identified candidate colorectal cancer outcome states based on a review of the literature and interviews with health care professionals. We organized patient focus groups from each of the candidate outcome states to examine their homogeneity and define their associated areas of morbidity. After analyzing the focus group transcripts, we identified and described outcome states of colorectal cancer for future incorporation into a utilities assessment instrument.

RESULTS

Six candidate outcome states of colorectal cancer were identified based on disease stage and location at diagnosis. Thirty-eight patients then participated in six focus groups. Analysis of the focus group transcripts revealed seven areas of morbidity associated with colorectal cancer. These areas included problems with social interaction and cognition, fear of cancer recurrence, pain, fatigue, changes in bowel habits, and sexual dysfunction. Based on differences in the intensity and frequency of the symptoms reported in each of these areas, seven distinct outcome states of colorectal cancer were identified and described.

CONCLUSION

Clinically distinct outcome states of colorectal cancer are determined by the stage and location of the cancer at the time of diagnosis. Descriptions of these outcome states were created using data collected from patient focus groups. These descriptions can be incorporated into a utilities assessment instrument.

TR1, a new member of the tumor necrosis factor receptor superfamily, induces fibroblast proliferation and inhibits osteoclastogenesis and bone resorption

A newly identified member of the tumor necrosis factor receptor (TNFR) superfamily shows activities associated with osteoclastogenesis inhibition and fibroblast proliferation. This new member, called TR1, was identified from a search of an expressed sequence tag database, and encodes 401 amino acids with a 21-residue signal sequence. Unlike other members of TNFR, TR1 does not contain a transmembrane domain and is secreted as a 62 kDa glycoprotein. TR1 gene maps to chromosome 8q23-24.1 and its mRNA is abundantly expressed on primary osteoblasts, osteogenic sarcoma cell lines, and primary fibroblasts. The receptors for TR1 were detected on a monocytic cell line (THP-1) and in human fibroblasts. Scatchard analyses indicated two classes of high and medium-high affinity receptors with a kD of approximately 45 and 320 pM, respectively. Recombinant TR1 induced proliferation of human foreskin fibroblasts and potentiated TNF-induced proliferation in these cells. In a coculture system of osteoblasts and bone marrow cells, recombinant TR1 completely inhibited the differentiation of osteoclast-like multinucleated cell formation in the presence of several bone-resorbing factors. TR1 also strongly inhibited bone-resorbing function on dentine slices by mature osteoclasts and decreased 45Ca release in fetal long-bone organ cultures. Anti-TR1 monoclonal antibody promoted the formation of osteoclasts in mouse marrow culture assays. These results indicate that TR1 has broad biological activities in fibroblast growth and in osteoclast differentiation and its functions.

Nurses' aid. Labor groups look to nursing to boost their dwindling ranks, promising tough tactics

Looking to replenish their dwindling ranks, old-line labor unions have turned to health care--especially to hospital nurses. Though less than a fifth of the nation's 2.2 million RNs belong to unions, labor groups are raiding each other, not organizing new collective bargaining units.