Managed care experiences of clinical neuropsychologists

Abstract

Although the eventual outcomes of what has become known as ‘health care reform’ are still far from clear, it is essential that clinical neuropsychologists begin to evaluate and respond, individually and as a discipline, to the evolving changes in national health care. With timely information regarding the impact of these changes in health care management, neuropsychologists can proactively develop, distribute, and implement expectations regarding appropriate standards of care among policy makers and reimbursement sources. Within this context, the results of a brief national survey of beliefs, experiences, and concerns of 259 clinical neuropsychologists are discussed. In sum, the majority of clinical neuropsychologists believe that health care ‘reform’, will have a negative effect on their practice, and many report serious difficulties already experienced under managed care systems. At least one third of clinical neuropsychologists sampled have experienced reductions in income levels, hourly reimbursement, referral sources, and overall number of referrals secondary to working within a managed care system, and more than half report having been excluded as providers from managed care systems. Additional concerns include increased paperwork and administrative time, loss of control over decisions essential to designing appropriate neuropsychological batteries, lack of appropriate representation, and diminished patient care. Proactive recommendations for dealing with these health care economic changes are presented.     

Mannitol-induced rebleeding from intracranial aneurysm. Case report

A case is presented in which rebleeding from an intracranial saccular aneurysm occurred a few minutes after intravenous administration of mannitol during surgery. The relationship between the reducing effect of mannitol on elevated intracranial pressure and the increased pressure gradient across the aneurysm wall, causing risk of rebleeding, is discussed. Procedures that can reduce this risk are summarized.     

First direct demonstration of preferential release of citrate from astrocytes using [13C]NMR spectroscopy of cultured neurons and astrocytes

Primary cultures of cerebral cortical neurons or astrocytes or the two cell types together (co-cultures) were incubated with [1-13C]glucose for 20 or 48 h. Subsequently, perchloric acid (PCA) extracts of the cells as well as redissolved lyophilized media were subjected to NMR spectroscopy in order to detect 13C-labeled amino acids (glutamine, glutamate, gamma-aminobutyrate (GABA)) and other metabolites (lactate, tricarboxylic acid cycle (TCA) constituents). NMR spectra of PCA extracts of neurons or co-cultures exhibited distinct peaks for glutamate and GABA whereas the PCA extracts of astrocytes and co-cultures showed peaks corresponding to glutamine and glutamate. This pattern is consistent with the neuronal location of the GABA synthesizing enzyme glutamate decarboxylase and the astrocytic localization of the glutamine synthesizing enzyme, glutamine synthetase. NMR spectra of the incubation media showed clearly that 13C-labeled citrate, alanine and glutamine were synthesized and released from astrocytes since only media from the astrocyte cultures or co-cultures or neurons and astrocytes contained these metabolites in detectable amounts. It may be concluded that astrocytes play an important role supplying neurons with precursors for biosynthesis of glutamate and GABA such as glutamine and TCA cycle constituents. Since among the latter only citrate could be found in significant amounts it may be hypothesized that this may be the quantitatively most important TCA constituent to be released from astrocytes and subsequently utilized by neurons.     

Placental function studies in low birth weight infants with and without dysmaturity

Maternal blood levels of human placental lactogen and schwangerschaftsprotein 1 were measured in 51 women who delivered a growth-retarded infant. The levels were substantially lower in the 27 women whose infants were clinically dysmature than in the 24 women whose infants were small but of normal appearance. About one-half (44%) the cases of true dysmaturity had abnormal concentrations of human placental lactogen (less than 4 mg/L), whereas none of the small but normal group had values in this zone. It is concluded that biochemical tests of this type reflect dynamic aspects of placental function and not simply the overall size of the fetus and placenta.     

The blood-brain barrier to horseradish peroxidase under normal and experimental conditions

Summary This review paper deals with the transport of the protein tracer horseradish peroxidase across cerebral vessels under normal and various experimental conditions.Electronmicroscopical investigations have revealed that, under normal conditions, a minor vesicular transfer of intravenously injected peroxidase occurs across the endothelium in segments of arterioles, capillaries and venules, especially in arterioles with a diameter about 15–30 . This normally occurring vesicular transport is susceptible to various experimental conditions. Thus the transfer of tracer increases when a hypertonic solution is injected into the internal carotid artery presumably due to vesicular transport.Extensive acute hypertension of short duration also increases the vesicular transfer of peroxidase from blood to brain. Identical observations are obtained when the hypertension is evoked by intravenous injection of phentolamine and by electrically induced seizures.During the postischemic period, one hour after release of the occlusion of an internal carotid artery in the Mongolian gerbil the vesicular transport of peroxidase is increased across the endothelium of cerebral vessels. The explanation may be release of serotonin from blood platelets during the occlusion. The serotonin could then increase the blood pressure locally in the brain resulting in an enhanced permeability.Serotonin, after perfusion through the cerebral ventricular system, is also able to increase the normally occurring vesicular transfer. The most likely mechanism behind this phenomenon seems at the moment to be local hypertension evoked by serotonin-induced vasoconstriction of arterioles.Finally, the enhanced vesicular transport across cerebral endothelium caused by porto-caval anastomosis is mentioned and the possible role of disturbances in the metabolism of amines as responsible for the extravasation is discussed.     

Ultrastructure of the subgingival microflora in juvenile periodontitis.

The ultrastructure of the subgingival deposits on the root surfaces of teeth affected by juvenile periodontitis was studied on 12 teeth from nine individuals, 15--30 years of age. The deposits consisted of either microbial masses associated with a pellicle, or of a cuticular material almost free of bacteria. Gram-negative rods and filaments were the predominant microorganisms. "Corncob" configurations consisting of filamentous bacteria surrounded by Gram-positive cocci, and "bristle brush" formations comprising corncobs surrounded by long rods were observed in the superficial layer of the plaque. Spirochetes and flagellated rods constituted a major segment of the microflora. The present data indicated that the deep pockets in juvenile periodontitis harbor a sparse but relatively characteristic microbial population.     

Bone mineral content and bone metabolism in young adults with severe periodontitis

OBJECTIVES: To clarify in young adults with severe periodontitis (1) whether the bone mineral content (BMC) or density (BMD) in the mandible/other skeletal sites and the systemic bone metabolism differed from normal and (2) whether mandibular/forearm BMC did change during the 5 to 10-year follow-up. MATERIAL AND METHODS: 24 young otherwise normal patients with verified severe periodontitis were included, of which 20 attended the follow-up visit. Mandibular/forearm BMC was measured at both visits by dual-photon absorptiometry, supplemented with femoral neck/lumbar spine BMD measurements at follow-up visit by dual-energy X-ray absorptiometry. Serum alkaline phosphatase/ionized calcium, urinary excretion of pyridinoline/deoxy-pyridinoline were analysed at the follow-up visit. A conventional periodontal examination was performed at both visits. RESULTS: Mandibular BMC was significantly below normal mean BMC at both visits. The mandibular Z-scores were < or = -2.00 in 33.3% (8/24). BMC/BMD in the remaining sites and the values for bone markers did not differ from normal. Mandibular/forearm BMC was stable while a significant aggravation of alveolar bone loss occurred during the trial without change of probing depth. CONCLUSIONS: Severe periodontitis in young adults seems to be a local disorder associated with relatively low BMC in the jaws without systemic alterations of BMC/BMD and bone metabolism.