Surface markers expressed by multipotent human and mouse neural progenitor cells include tetraspanins and non-protein epitopes

Surface molecules play important roles in a wide range of cellular functions, yet little has been reported regarding the expression of such markers by neural stem cells. Here, multipotent human neural progenitor cells (hNPCs) were expanded as a monolayer in the presence of fibroblast/epidermal growth factor, harvested, labeled with monoclonal antibodies, and analyzed by flow cytometry. Positive markers included CD9, CD15, CD81, CD95 (Fas), GD(2) ganglioside, and major histocompatibility complex class I and beta2 microglobulin, as well as low levels of the hematopoietic stem cell marker CD34. Of these, mouse NPCs were positive for CD9, CD15, CD81, and GD(2) ganglioside. The markers reported here have been implicated in a wide range of cellular functions including proliferation, migration, differentiation, apoptosis, and immune recognition.

Antigenicity and immunogenicity of allogeneic retinal transplants

The transplantation of neuronal cells and tissues represents a promising approach for the treatment of incurable neurodegenerative diseases. Indeed, it has been reported recently that retinal transplantation can rescue photoreceptor cells and delay age-related changes in various retinal layers in rodents. However, retinal grafts deteriorate progressively after placement in recipients' eyes. Here we investigated whether a host's immune response elicited toward the graft contributes to its deterioration. Using an ELISA spot assay, we measured T cell responses to retinal tissues placed in the vitreous cavity of syngeneic and allogeneic mice. We found that allogeneic retinas induced potent alloimmune responses mediated by T cells secreting type 1 cytokines (IFN-gamma and IL-2). No response was found in mice engrafted with syngeneic retinas. In addition, all syngeneic retinal grafts displayed no signs of tissue damage (at 55 days), while the majority of allogeneic retinas deteriorated as early as 12 days after placement. Next, we showed that anti-donor responses occurred within two phenotypically and functionally distinct T cell subsets: CD4+ T cells secreting IL-2 and CD8+ T cells producing IFN-gamma. Importantly, CD4+ T cells were necessary and sufficient to cause graft deterioration, while CD8+ T cells did not contribute to this process.

Photoreceptor rescue after low-dose intravitreal IL-1beta injection in the RCS rat

Photoreceptor survival in the dystrophic rat was evaluated following administration of IL-1beta at dosages much lower than those used previously for this purpose. Royal College of Surgeons rats (pink-eyed, pigmented, or non-dystrophic) received 1 microl intravitreal injections of murine recombinant IL-1beta (0.5, 2, or 5 microg ml(-1); at 3 or 4 weeks of age). Eyes were harvested 4 weeks later and outer nuclear layer profiles counted. Additional animals received intravitreal basic fibroblast growth factor (1000 microg ml(-1)), or vehicle alone. Others were treated with IL-1beta to evaluate the inflammatory response (CD45+ profiles) or visual function via opto-kinetic response. IL-1beta was associated with photoreceptor rescue that was both dose-dependent and comparable to that seen following high-dose basic fibroblast growth factor. Significant anatomical rescue relative to controls was seen in both pink-eyed and pigmented strains, although the degree and distribution varied between strains. Functional rescue was confirmed by opto-kinetic response using the pigmented strain. At 5 microg ml(-1), IL-1beta resulted in numerous CD45+ profiles within the retina and vitreous. Infiltration peaked at 48 hr and was minimal at 4 weeks, without dysplastic sequelae. IL-1beta therefore induces visually significant photoreceptor rescue in a potent, dose-dependent manner that need not entail cytoarchitectural disruption. This is consistent with the known association between injury and rescue in the rat retina. Neuroprotection may be a general, if under-appreciated, consequence of inflammatory cascade activation.

The development of a survey instrument for community health improvement

OBJECTIVE

To develop a survey instrument that could be used both to guide and evaluate community health improvement efforts.

DATA SOURCES/STUDY SETTING

A randomized telephone survey was administered to a sample of about 250 residents in two communities in Lehigh Valley, Pennsylvania in the fall of 1997.

METHODS

The survey instrument was developed by health professionals representing diverse health care organizations. This group worked collaboratively over a period of two years to (1) select a conceptual model of health as a foundation for the survey; (2) review relevant literature to identify indicators that adequately measured the health constructs within the chosen model; (3) develop new indicators where important constructs lacked specific measures; and (4) pilot test the final survey to assess the reliability and validity of the instrument.

PRINCIPAL FINDINGS

The Evans and Stoddart Field Model of the Determinants of Health and Well-Being was chosen as the conceptual model within which to develop the survey. The Field Model depicts nine domains important to the origins and production of health and provides a comprehensive framework from which to launch community health improvement efforts. From more than 500 potential indicators we identified 118 survey questions that reflected the multiple determinants of health as conceptualized by this model. Sources from which indicators were selected include the Behavior Risk Factor Surveillance Survey, the National Health Interview Survey, the Consumer Assessment of Health Plans Survey, and the SF-12 Summary Scales. The work group developed 27 new survey questions for constructs for which we could not locate adequate indicators. Twenty-five questions in the final instrument can be compared to nationally published norms or benchmarks. The final instrument was pilot tested in 1997 in two communities. Administration time averaged 22 minutes with a response rate of 66 percent. Reliability of new survey questions was adequate. Face validity was supported by previous findings from qualitative and quantitative studies.

CONCLUSIONS

We developed, pilot tested, and validated a survey instrument designed to provide more comprehensive and timely data to communities for community health assessments. This instrument allows communities to identify and measure critical domains of health that have previously not been captured in a single instrument.

Graft location affects functional rescue following RPE cell transplantation in the RCS rat

Photoreceptor (PRC) rescue in the dystrophic Royal College of Surgeons (RCS) rat has been well documented following a variety of interventions. Although the dystrophic process is asymmetric with respect to the horizontal meridian, little attention has been paid to the effect of topographic position on treatment outcome. In this study, RPE cells from adult congenic nondystrophic animals were injected into the subretinal space of 1-month-old dystrophic RCS rats in either the dorsal or the ventral equatorial region. Animals were followed longitudinally during the degenerative process using the pupillary light reflex (PLR). The parameter of the PLR most sensitive to PRC rescue is latency at low light levels. At 3 months of age this parameter showed statistically better performance (ANOVA, P = 0.016) for eyes with grafts placed dorsally compared to those placed ventrally or untreated controls. There was no treatment effect on amplitude. By 6 months of age the dorsal/ventral disparity in latency was less apparent and amplitude remained equivalent across groups. Late analysis of retinal whole-mounts using RT-97 fluorescent labeling showed extensive irregularities in ventral axonal morphology in all treatment groups. These results indicate that functional rescue of the RCS retina is significantly influenced by the local degenerative timetable. The role of initial local conditions on treatment outcome is worthy of consideration in other models of neuroprotection.

Transplantation of human neural progenitor cells to the vitreous cavity of the Royal College of Surgeons rat

Human neural progenitor cells, originally isolated from prenatal donor tissue at 17 weeks of development, were cultured as neurospheres and transplanted to the vitreous cavity of dystrophic Royal College of Surgeons rats with, or without, cyclosporin A immunosuppression. Donor cells were either unlabeled or prelabeled, the latter utilizing incubation with BrdU or adenoviral modification to express green fluorescent protein. Recipients of various ages were examined at 1, 2, and 4 weeks postgrafting. Transplanted human neural progenitor cells survived in the host vitreous for at least 4 weeks and maintained expression of green fluorescent protein for at least 2 weeks. After 2 weeks in vivo, grafted cells differentiated morphologically, coincident with expression of the neuronal marker MAP, indicating mature neuronal differentiation. The extensive intraretinal migration previously shown using rat progenitor cells in the Royal College of Surgeons rat model was not seen in this experiment, suggesting that high levels of neuronal migration may depend at least in part upon species-specific molecular cues. Human neural progenitor cells represent a renewable source of multipotent human cells capable of in vivo neuronal development and a potential means of delivering therapeutic factors intraocularly. Human neural progenitor cells therefore provide a useful tool for studies of neural development and differentiation in the dystrophic eye.

Acute hypoglycemia impairs the functioning of the central but not peripheral nervous system

Acute hypoglycemia impairs functions of the central nervous system, but few controlled studies have assessed the impact of hypoglycemia on the function of the peripheral nervous system. Sixteen non-diabetic humans underwent two separate hyperinsulinemic glucose clamp procedures on different study days, in a counter-balanced fashion. On one occasion, euglycemia was maintained (blood glucose, 5.0 mmol l(-1)), and on the other occasion, hypoglycemia (blood glucose, 2.6 mmol l(-1)) was induced. During each condition, subjects performed a combined psychometric, cognitive-experimental and psychophysical test battery, and measures were made (in the dominant median and common peroneal nerves) of the motor nerve conduction velocities and the amplitudes of the motor action potentials. Hypoglycemia caused impaired performance of general cognitive and information processing tasks (P<.05), but nerve conduction velocities and the amplitudes of motor action potentials were unaffected. Conduction velocities of the common peroneal nerve decreased from baseline within each experimental condition, perhaps due to hyperinsulinemia. Overall, these results demonstrate that multiple levels of information processing in the brain may alter while peripheral nerve function remains intact, and imply that peripheral neurons do not have the same obligate requirement for glucose as a metabolic fuel as neurons of the central nervous system.

Mechanism of capsid assembly for an icosahedral plant virus

Capsids of spherical viruses share a common architecture: an icosahedral arrangement of identical proteins. We suggest that there may be a limited number of common assembly mechanisms for such viruses. Previous assembly mechanisms were proposed on the basis of virion structure but were not rigorously tested. Here we apply a rigorous analysis of assembly to cowpea chlorotic mottle virus (CCMV), a typical, small, positive-strand RNA virus. The atomic resolution structure of CCMV revealed an interleaving of subunits around the quasi-sixfold vertices, which suggested that capsid assembly was initiated by a hexamer of dimers (Speir et al., 1995, Structure 3, 63-78). However, we find that the capsid protein readily forms pentamers of dimers in solution, based on polymerization kinetics observed by light scattering. Capsid assembly is nucleated by a pentamer, determined from analysis of the extent of assembly by size-exclusion chromatography. Subsequent assembly likely proceeds by the cooperative addition of dimers, leading to the T = 3 icosahedral capsid. At high protein concentrations, the concentration-dependent nucleation reaction causes an overabundance of five-dimer nuclei that can be identified by classical light scattering. In turn these associate to form incomplete capsids and pseudo-T = 2 capsids, assembled by oligomerization of 12 pentamers of dimers. The experimentally derived assembly mechanisms of T = 3 and pseudo-T = 2 CCMV capsids are directly relevant to interpreting the structure and assembly of other T = 3 viruses such as Norwalk virus and pseudo-T = 2 viruses such as the vp3 core of blue tongue virus.

How should xanthine oxidase-generated superoxide yields be measured?

The rate of formation of superoxide measured by its reduction of tetranitromethane (TNM) and by its reduction of ferric cytochrome c (Fe(III) cc) are in excellent agreement when the superoxide is generated from a simple chemical precursor. In contrast, the rate of formation of superoxide generated in the reaction of xanthine oxidase with acetaldehyde is much higher (up to a factor of 6) when measured with TNM and compared with Fe(III) cc. It is shown that Fe(III) cc measures superoxide that has diffused from the enzyme, and that TNM probably scavenges all the dioxygen that is reduced by one electron by the enzyme. The TNM traps enzyme-bound superoxide in competition with the second-electron transfer and proton transfer, which normally yield hydrogen peroxide. The proton transfer is probably rate determining, k(p) </= 3.8x10(3)s(-1).

Neuronal differentiation and morphological integration of hippocampal progenitor cells transplanted to the retina of immature and mature dystrophic rats

Attempts to repopulate the retina with grafted neurons have been unsuccessful, in large part because donor cells prefer not to integrate with those of the host. Here we describe the first use of neural progenitor cells in the diseased adult retina. Adult rat hippocampal progenitor cells were injected into the eyes of rats with a genetic retinal degeneration. After survival times up to 16 weeks, the retinae of 1-, 4-, and 10-week-old recipients exhibited widespread incorporation of green fluorescent protein-expressing (GFP+) donor cells into the host retina. The 18-week-old recipients showed a similar pattern, but with fewer cells. Grafted cells expressed the mature neuronal markers NF-200, MAP-5, and calbindin. GFP+ cells extended numerous neurites into the host plexiform layers and these processes were intimately associated with synaptophysin+ profiles. GFP+ neurites also extended into the host optic nerve head. These results demonstrate the differentiation of substantial numbers of new neurons within the mature dystrophic retina.

Using a SANE interdisciplinary approach to care of sexual assault victims

BACKGROUND

Many hospitals have recognized the need to develop policies and procedures for female sexual assault victims' prompt access to emergency medical care and for collecting law enforcement evidence. At Lehigh Valley Hospital (Allentown, Penn), care in the emergency department (ED) for sexual assault victims was covered by oncall obstetricians and gynecologists. Although many aspects of rape management were in place, a busy ED with varying levels of physician response and exposure to the process of rape management contributed to a lack of standardized, objective, timely, and compassionate medical management of sexual assault victims. DEVELOPING THE PROGRAM: The Sexual Assault Nurse Examiner (SANE) interdisciplinary approach to care of sexual assault victims was implemented in May 1998. Community education and awareness projects emphasized prevention of sexual assault and domestic violence, as well as minimization of trauma for victims by promoting services that provide a supportive, caring, and healing environment.

RESULTS

Comparing a baseline group of 130 sexual assault victims with 39 patients who were evaluated after the SANE approach was implemented indicated increased clinical interaction and significant improvements in quality indicators, such as completeness of evaluation and information gathered relevant to medical-legal issues.

DISCUSSION

Law enforcement staff developed a more collaborative relationship with SANE examiners through the interdisciplinary team approach. Collaborative relationships were initiated with several other hospitals in the hospital's integrated delivery system to help offset some of the program's training, continuing education, and on-call costs and to allow for joint outcomes collection. The SANE program became a core ED service in July 1999.

Differences in the performance of commercially available 10-g monofilaments

OBJECTIVE

This independent study was designed to determine the accuracy of 10-g monofilaments manufactured and supplied by popular commercial companies.

RESEARCH DESIGN AND METHODS

A total of 160 new 10-g monofilaments (30 Semmes-Weinstein monofilaments [North Coast Medical], 30 Timesco/Sensory Testing Systems monofilaments, 50 Owen Mumford Neuropens, and 50 Bailey Instruments monofilaments) were tested using a calibrated load cell. Each monofilament was subjected to 10 mechanical bucklings of 10 mm while the load cell detected the maximum buckling force. Longevity testing was performed on a subset of the monofilaments by subjecting them to continuous compressions until the buckling force was <9 g.

RESULTS

The accuracy of monofilaments to produce a buckling force of 10 g varies among manufacturers. Bailey Instruments and Owen Mumford filaments were the most accurate with 100% buckling within +/-1.0 g of 10 g. Only 70% of the Semmes-Weinstein monofilaments from North Coast Medical buckled within +/-1.0 g of 10 g. A total of 80% of Timesco filaments buckled at <8 g. Longevity tests on Bailey Instruments and Owen Mumford monofilaments demonstrated that 80% continued to buckle within 10% of 10 g after 100 compressions, but only 50% were within this range after 200 compressions. The maximum amount of recovery achieved in any monofilament occurred within 24 h.

CONCLUSIONS

Monofilaments made by either Bailey Instruments or Owen Mumford are recommended for use in clinical practice. North Coast Medical monofilaments may operate differently in the U.S. because of different environmental conditions such as differences in humidity. Timesco/Sensory Testing Systems monofilaments were neither accurate enough nor Conformity European marked to recommend their use in the U.K. Longevity and recovery testing suggest that each monofilament will survive usage on approximately 10 patients before needing a recovery time of 24 h before further use.

Systemic immune deviation in the brain that does not depend on the integrity of the blood-brain barrier

OVA injected into the brain of normal mice evoked a deviant immune response (brain-associated immune deviation (BRAID)) that was deficient in OVA-specific delayed-type hypersensitivity. This response was not dependent on an intact blood-brain barrier since BRAID was induced even when OVA was injected into a newly created lesion site with extensive BBB leakage. However, newly activated microglia at the injection site 2 days after ablation of the striatum correlated with the loss of BRAID. At day 4 after trauma, when activated microglia were only visible further away from the injection site, BRAID was again able to be induced. In contrast to immune deviation elicited via the eye, an intact spleen was not required for BRAID, nor was BRAID adoptively transferable with spleen cells. In contrast i.v. injection of cervical lymph node cells harvested 8 days after OVA injection into the striatum was able to transfer BRAID into naive animals. Together, these data indicate that immune privilege in the brain is actively maintained and is mediated by an immune deviation mechanism that differs from eye-derived immune deviation and arises even when the BBB is compromised.

Strand cleavage of supercoiled DNA by water-soluble peroxyl radicals. The overlooked importance of peroxyl radical charge

It is well established that the peroxyl radicals formed during the thermal decomposition of 2,2'-azobis(amidinopropane), ABAP, in oxygenated water can cleave double-stranded DNA, from which fact it has been concluded that peroxyl radicals, as a general class, can induce DNA strand scission. However, the ABAP-derived radicals are positively charged, and DNA is a negatively charged polyanion. Moreover, the relatively small and, therefore, free to diffuse peroxyl radicals likely to be formed in vivo will generally be negatively charged or neutral. Plasmid supercoiled DNA [pBR 322, 4361 base pairs (bp)] was reacted with known, equal fluxes of two positively charged peroxyl radicals, a negatively charged peroxyl radical, and a neutral peroxyl radical. The two positively charged peroxyl radicals degraded >/=80% of the supercoiled pBR 322 at a flux of 4 radicals/bp, but the negatively charged and neutral peroxyl radicals had no significant effect even at a flux as high as 24 radicals/bp. The same lack of effect on the DNA was also observed with high fluxes of superoxide/hydroperoxyl radicals. Similar results were obtained with another supercoiled DNA, pUC 19, except that pUC 19 is somewhat more sensitive to strand scission by positively charged peroxyl radicals than pBR 322. We conclude that most of the peroxyl radicals likely to be formed in vivo have little or no ability to induce DNA strand scission and that the potential role of electrostatics in radical/DNA reactions should always be considered.

The management of neurogenic arthropathy: a tale of two charcots

The pathogenesis and natural history of Charcot neuroarthropathy is often poorly understood. The diagnosis and treatment of Charcot feet can also prove difficult. Two case histories are used to illustrate the key points in the management of this potentially devastating condition.

Urinary hyaluronic acid and hyaluronidase: markers for bladder cancer detection and evaluation of grade

PURPOSE

Specific patterns of progression and frequent recurrence of bladder tumors determine the choice of treatment, frequency of surveillance, quality of life, and ultimately, patient prognosis. The prognosis would be improved if an accurate noninvasive test was available for diagnosis. Identification of markers that function in bladder cancer progression would be helpful in designing such diagnostic tests. The glycosaminoglycan, hyaluronic acid (HA), promotes tumor metastasis. Hyaluronidase (HAase), an endoglycosidase, degrades HA into small fragments that promote angiogenesis. We have previously shown that both HA and HAase are associated with bladder cancer and may function in bladder tumor angiogenesis. In this study we examined whether urinary HA and HAase levels serve as bladder cancer markers.

MATERIALS AND METHODS

Among the 513 urine specimens analyzed, 261 were from transitional cell carcinoma (TCC) patients, 9 from patients with non-TCC tumors, and 243 from controls (normals, patients with other genitourinary (GU) conditions or a history of bladder cancer (HxBCa)). The urinary HA and HAase levels were measured by two ELISA-like assays that utilize a biotinylated HA binding protein for detection. These levels were normalized to total urinary protein and were expressed as ng./mg. (HA test) and mU/mg. (HAase test), respectively.

RESULTS

The urinary HA levels were elevated (2.5 to 6.5 fold) in bladder cancer patients (1173.7+/-173.4; n = 261) as compared with normals (246.1+/-38.5; n = 41); GU patients (306.6+/-32.2; n = 133), and patients with a HxBCa (351.1+/-49.1; n = 69) (p <0.001). The urinary HAase levels were elevated (3 to 7 fold) in G2/G3 bladder cancer patients (26.2+/-3.2) as compared with normals (4.5+/-0.9) and patients with either GU conditions (5.8+/-1.3), HxBCa (8.2+/-2.6) or G1 tumors (9.7+/-2.5) (p <0.001). The HA test showed 83.1% sensitivity, 90.1% specificity and 86.5% accuracy in detecting bladder cancer, regardless of the tumor grade. The HAase test showed 81.5% sensitivity, 83.8% specificity and 82.9% accuracy to detect G2/G3 patients. Combining the inferences of the HA and HAase tests (HA-HAase test) resulted in detection of bladder cancer, regardless of tumor grade and stage, with higher sensitivity (91.2%) and accuracy (88.3%), and comparable specificity (84.4%).

CONCLUSION

Our results show that the HA-HAase urine test is a noninvasive, highly sensitive and specific method for detecting bladder cancer and evaluating its grade.

Evaluation of guidelines for the use of telemetry in the non-intensive-care setting

To determine if the American College of Cardiology (ACC) cardiac monitoring guidelines accurately stratify patients according to their risks for developing clinically significant arrhythmias in non-intensive-care settings, we conducted a prospective cohort study of 2,240 consecutive patients admitted to a non-intensive-care telemetry unit over 7 months. Sixty-one percent of patients were assigned to ACC class I (telemetry indicated in most patients), 38% to class II (telemetry indicated in some), and 1% to class III (telemetry not indicated). Arrhythmias were detected in 13.5% of the class I patients, 40.7% of the class II patients, and 12% of the class III patients (p <.001). Telemetry detected an arrhythmia resulting in transfer to an intensive care unit in 0.4% of the class I patients, 1.6% of the class II patients, and none of the class III patients (p =.006). Telemetry led to a change in management for 3.4% of the class I patients, 12.7% of the class II patients, and 4% of the class III patients (p <.001). When patients with chest pain as the reason for admission were moved from class I to class II and patients with arrhythmias as the reason for admission were moved from class II to class I, more arrhythmias and more clinically significant arrhythmias occurred in class I patients and the trends from class I to class III were more consistent with the purpose of the guidelines. These findings indicate that when the ACC guidelines are reexamined, consideration should be given to changing them so they are more useful in non-intensive-care settings.

Complications of advanced prostate cancer

Currently, there is a lot of focus directed toward discovering treatments for patients with hormone refractory prostate cancer (HRPC) that will lead to increased survival. Until such treatments emerge, palliation is important to ensure patients the highest possible quality of life. Most disabling among symptoms associated with disease progression are bone pain, bone fracture, urinary tract obstruction, spinal cord compression, coagulation disorders, anemia, and edema. Diverse treatments, such as radiation therapy, surgery, chemotherapy, and supportive measures, can improve the impact of these problems, although improved symptom control is needed in some areas.

Identification of bladder tumor-derived hyaluronidase: its similarity to HYAL1

The glycosaminoglycan hyaluronic acid (HA) and its degrading enzyme, hyaluronidase, are intricately associated with tumor metastasis and angiogenesis. HA promotes tumor cell adhesion and migration, whereas its small fragments stimulate angiogenesis. Such small HA fragments are generated from the degradation of HA by hyaluronidase. We have previously shown (V. B. Lokeshwar et al., Cancer Res., 57: 773-777, 1997) that the HA levels are elevated in the urine and tumor tissues of bladder cancer patients regardless of the tumor grade (G). The hyaluronidase levels were found to be elevated in the urine and tumor tissues of G2 and G3 bladder cancer patients. Furthermore, angiogenic HA fragments were isolated from the urine of G2/G3 bladder cancer patients, which stimulated endothelial cell proliferation, a key event in angiogenesis. In this study, we characterized the bladder tumor-derived hyaluronidase. Analysis of hyaluronidase activity in the culture-conditioned media (CM) of 11 bladder cancer cell lines, using an ELISA-like assay and a substrate (HA)-gel technique, showed that the invasive bladder cancer cell lines secrete elevated levels of a Mr approximately 60,000 hyaluronidase. Reverse transcription-polymerase chain reaction, cloning, and sequence analyses revealed the expression of an HYAL1 transcript in bladder cancer lines. HYAL1 encodes for a hyaluronidase that is present in serum. Immunoblot analysis using an anti-HYAL1 peptide IgG confirmed the presence of a Mr approximately 60,000 HYAL1-related protein in the CM of bladder cancer cell lines, in the urine specimens from G2 and G3 bladder cancer patients, and in the partially purified preparations of bladder tumor-derived hyaluronidase. No HYAL1-related protein was detected in urine specimens from normal individuals, G1 bladder cancer patients, and patients with a history of bladder cancer but no disease at the time of testing. The bladder tumor-derived hyaluronidase present in CM and partially purified preparations was found to have maximum activity at a pH range of 4.1-4.3. The identification of bladder tumor-derived hyaluronidase should help in elucidating its role in bladder tumor progression.

Intracellular and cell-surface distribution of amyloid precursor protein in cortical astrocytes

Amyloid peptides that aggregate to form plaques in Alzheimer's disease are derived from secretory processing of the amyloid precursor protein (APP). Transport of APP to the cell surface may be prerequisite for non-amyloidogenic APP processing and the secretion of soluble APP (APPs), while missorting or reinternalization of APP to intracellular compartments can promote amyloid formation. In cultured astrocytes, APP mRNA and holoprotein are increased by elevations in cAMP levels, and 8-Bromo-cAMP promotes process formation on these cells. We now report that treatment of cultured astrocytes with 8-Bromo-cAMP increased intracellular and cell surface APP in the soma and perinuclear region as detected by immunolabeling with monoclonal antibody 22C11 and polyclonal antibody Kunitz-type protease inhibitor (KPI) (against the N-terminus and KPI domain of APP, respectively) and led to intense but discontinuous labelling of APP on the surface of astrocytic processes. Northern and Western blot analyses confirmed that 8-Bromo-cAMP treatment of cultured astrocytes also increased APP mRNA and KPI-containing APP holoprotein, implying that the intense APP immunolabeling observed in 8-Bromo-cAMP treated astrocytes was not derived from truncated forms of APP (e.g., APPs), but reflected high levels of APP holoprotein containing intact amyloid peptides. Discontinuous cell surface staining in process-bearing astrocytes may be caused by miscompartmentalization of APP related to rearrangement of the cytoskeleton. Inasmuch as intracellular APP is not accessible for non-amyloidogenic processing, we suggest that the increased immunoreactivity of intracellular APP in process-bearing astrocytes may predispose the cells to increased amyloid production.

Evidence for the Will Rogers phenomenon in migration of employees to managed care plans

Employees have increasing opportunities to enroll in managed care plans, and employers tend to favor these plans because of their lower costs. However, lower costs may be the result of selection of healthier patients into managed care plans. This study measured differences in health care utilization across an indemnity plan and a managed care plan, and for all employees together. We found that apparent increases in utilization in both indemnity and managed care plans disappeared when the plans were viewed together, reflecting the migration of sicker patients from indemnity plans to managed care plans.

Patients, physicians, and professional knowledge: implications for CQI

As we consider how to improve health care, we must understand the transformation that focuses on the physician's role in health care. A multidisciplinary team is critical for improvement activities-hospital administrators, nurses, and other colleagues. All need to learn new knowledge and leadership skills, but there is a special need to understand underlying issues that will require a transformation in many physicians. This will not be easy--nor should it be. Physicians must continue to achieve the benefits for patients that come from traditional professional knowledge. However, there is an even greater need to understand how physicians can move from the dominance approach of the medical model to a partnership approach inherent in CQI. This article describes lessons learned from our CQI work with physician colleagues over the last several years. First the relationship of professional knowledge to knowledge for improvement is described, and then the individual patient-doctor relationship is reexamined. Next, the implications of knowledge for improvement for the roles of physicians in organized health care systems are considered.

The evaluation of hospital restructuring efforts: satisfaction, quality, and costs

This article reports on study evaluating the effects of hospital restructuring on patient satisfaction, nurse satisfaction, cost of care, and clinical quality. The restructuring involved facility redesign, telecommunications enhancement, and implementation of patient care processes incorporating multiskilled personnel and case facilitation systems. The results indicate improved patient and nurse satisfaction, decreased length of stay and variable cost per patient day, and good clinical outcomes.

The management of neurogenic arthropathy: a tale of two charcots

The pathogenesis and natural history of Charcot neuroarthropathy is often poorly understood. The diagnosis and treatment of Charcot feet can also prove difficult. Two case histories are used to illustrate the key points in the management of this potentially devastating condition.