Higher order genomic organization and epigenetic control maintain cellular identity and prevent breast cancer

Cells establish and sustain structural and functional integrity of the genome to support cellular identity and prevent malignant transformation. In this review, we present a strategic overview of epigenetic regulatory mechanisms including histone modifications and higher order chromatin organization (HCO) that are perturbed in breast cancer onset and progression. Implications for dysfunctions that occur in hormone regulation, cell cycle control, and mitotic bookmarking in breast cancer are considered, with an emphasis on epithelial-to-mesenchymal transition and cancer stem cell activities. The architectural organization of regulatory machinery is addressed within the contexts of translating cancer-compromised genomic organization to advances in breast cancer risk assessment, diagnosis, prognosis, and identification of novel therapeutic targets with high specificity and minimal off target effects.

Nonsurgical treatment and early return to activity leads to improved Achilles tendon fatigue mechanics and functional outcomes during early healing in an animal model

Achilles tendon ruptures are common and devastating injuries; however, an optimized treatment and rehabilitation protocol has yet to be defined. Therefore, the objective of this study was to investigate the effects of surgical repair and return to activity on joint function and Achilles tendon properties after 3 weeks of healing. Sprague-Dawley rats (N = 100) received unilateral blunt transection of their Achilles tendon. Animals were then randomized into repaired or non-repaired treatments, and further randomized into groups that returned to activity after 1 week (RTA1) or after 3 weeks (RTA3) of limb casting in plantarflexion. Limb function, passive joint mechanics, and tendon properties (mechanical, organizational using high frequency ultrasound, histological, and compositional) were evaluated. Results showed that both treatment and return to activity collectively affected limb function, passive joint mechanics, and tendon properties. Functionally, RTA1 animals had increased dorsiflexion ROM and weight bearing of the injured limb compared to RTA3 animals 3-weeks post-injury. Such functional improvements in RTA1 tendons were evidenced in their mechanical fatigue properties and increased cross sectional area compared to RTA3 tendons. When RTA1 was coupled with nonsurgical treatment, superior fatigue properties were achieved compared to repaired tendons. No differences in cell shape, cellularity, GAG, collagen type I, or TGF-β staining were identified between groups, but collagen type III was elevated in RTA3 repaired tendons. The larger tissue area and increased fatigue resistance created in RTA1 tendons may prove critical for optimized outcomes in early Achilles tendon healing following complete rupture. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:2172-2180, 2016.

Comparison of a multifilament stainless steel suture with FiberWire for flexor tendon repairs--an in vitro biomechanical study

Our goal was to investigate and compare the mechanical properties of multifilament stainless steel suture (MFSS) and polyethylene multi-filament core FiberWire in flexor tendon repairs. Flexor digitorum profundus tendons were repaired in human cadaver hands with either a 4-strand cruciate cross-lock repair or 6-strand modified Savage repair using 4-0 and 3-0 multifilament stainless steel or FiberWire. The multifilament stainless steel repairs were as strong as those performed with FiberWire in terms of ultimate load and load at 2 mm gap. This study suggests that MFSS provides as strong a repair as FiberWire. The mode of failure of the MFSS occurred by the suture pulling through the tendon, which suggests an advantage in terms of suture strength.

Child health insurance outreach through the emergency department: a pilot study

In 1997 the U.S. government funded the Children's Health Insurance Program (CHIP), but the 48 billion dollars initiative has had limited success in finding and enrolling uninsured children. While such children are more likely to receive care in emergency departments (EDs), no national initiative has targeted EDs for child health insurance outreach.

OBJECTIVE

As a pilot study for a national multicenter study, this study evaluated the effectiveness of child health insurance outreach in an ED setting.

METHODS

This was a prospective observational study of the outreach efforts of a single case manager from August 1998 to July 1999, performed at Foote Hospital ED in Jackson, Michigan (45,000 visits/year). All patients <or=18 years old presenting during the duty-hours of the intervention worker were eligible. The case manager approached the parent of all uninsured children and provided information and an application for government-sponsored health insurance. She followed up with a brief phone interview of each parent to determine whether the targeted child had received the insurance, and whether the new coverage was due to the ED referral. Missing information was confirmed from state insurance records. Data were analyzed with frequency tabulations and 95% confidence intervals.

RESULTS

Seventy-eight children participated (median age 7 years; 55% male; 87% white). Forty-four percent (95% CI = 32% to 55%) of families referred for government-sponsored child health insurance successfully obtained it; 31% (95% CI = 21% to 42%) could be traced directly to intervention efforts by interview (n = 17) or by state records (n = 7). Nineteen percent (95% CI = 11% to 30%) got other private insurance. Of those who got government-sponsored insurance due to the intervention, all but one were covered by Medicaid.

CONCLUSIONS

The ED may be an important outreach site for child health insurance programs. National efforts to address the lack of insurance among children should include partnerships with the ED.

Safety net research in emergency medicine: proceedings of the Academic Emergency Medicine Consensus Conference on "The Unraveling Safety Net"

A primary goal of the Academic Emergency Medicine Consensus Conference, "The Unraveling Safety Net: Research Opportunities and Priorities," was to explore a formal research agenda for safety net research in emergency medicine. This paper represents the thoughts of active health services researchers regarding the structure and direction of such work, including some examples from their own research. The current system for safety net care is described, and the emergency department is conceptualized as a window on safety net patients and systems, uniquely positioned to help study and coordinate integrated processes of care.

Treatment resistant depression and axis I co-morbidity

BACKGROUND

Treatment resistant depression (TRD) continues to present a formidable challenge to clinicians, accounts for over half of the annual costs associated with treatment for depression and causes great frustration to patients. Although there have been studies attempting to define TRD, little information is available as to the cause of TRD. One suggestion is that patients with TRD have a greater frequency of co-morbid psychiatric disorders, which explains their resistance to standard antidepressant treatments. The objective of this study was to compare the co-morbidity of Axis I disorders between a sample of TRD patients and a sample of non-TRD patients.

METHODS

TRD and non-TRD patients, recruited from two separate antidepressant treatment studies, were assessed for Axis I co-morbidity using the SCID-P for the DSM-III-R. Patients for the two samples were then matched for baseline HAM-D-17 total score and gender.

RESULTS

Results reveal that non-TRD patients had a higher rate of both lifetime and current generalized anxiety disorder co-morbidity than did the TRD patients. No other statistically significant differences in Axis I co-morbidity were found.

CONCLUSIONS

These findings do not support the idea that current or lifetime Axis I co-morbidity is more common in TRD than non-TRD patients. In fact, the only statistical difference showed non-TRD patients with higher co-morbidity rates.

Coinfection with Campylobacter species: an epidemiological problem?

AIMS

To determine the frequency of coinfection with multiple strains in sporadic cases of human Campylobacter infection.

METHOD AND RESULTS

During 1999 10 single colonies of Campylobacter were cultured from each of 53 positive faecal samples. Five isolates were taken from nonselective agar after passive filtration of faecal suspensions and five isolates were taken from selective agar plates. All isolates were sero- and phage typed and their antibiotic resistance determined. Pulsed-field gel electrophoresis and flagellin gene typing were performed on selected isolates. One patient was infected with Camp. coli, the remainder with strains of Camp. jejuni. The majority of patients was infected with a single strain of Campylobacter, but from each of four samples, 7.5%, two strains of Camp. jejuni, confirmed by molecular typing, were identified.

CONCLUSION

Coinfection occurs in sporadic cases of campylobacteriosis.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study has implications in outbreak investigation when distinct strains have been isolated from epidemiologically related patients and/or the suspected source or vehicle.

Renal artery stenosis: duplex US after angioplasty and stent placement

PURPOSE

To evaluate the hemodynamic outcome of technically successful percutaneous transluminal renal artery angioplasty and stent placement (PTRAS) with duplex ultrasonography (US).

MATERIALS AND METHODS

Eighteen patients who underwent PTRAS in 22 renal arteries were prospectively examined. All had abnormal preprocedural duplex US findings. Those who had significant renal artery stenosis (>70%) at angiography and underwent technically successful percutaneous interventions were enrolled. Standard intrarenal duplex US parameters (acceleration index [AI], acceleration time, waveform morphology grade, and resistive index) were compared before and after interventions.

RESULTS

A significant AI increase occurred after PTRAS (9.02 m/sec(2) +/- 4.85 [SD]), as compared with before intervention (2.34 m/sec(2) +/- 2.03; P <.001). Acceleration time significantly decreased from 0.084 second +/- 0.049 to 0.032 second +/- 0.008 (P <.01). There was also a significant resistive index increase from 0.69 +/- 0.12 to 0.79 +/- 0.12 (P <.01). Abnormal waveform morphology (modified Halpern waveform grade 3-6) was present in 19 (86%) of 22 intrarenal arteries prior to intervention, as compared with one (5%) after PTRAS (P <.001). In the instance in which an abnormal waveform persisted after intervention, waveform morphology improved from grade 6 to grade 3, with a concomitant AI increase from 0.96 to 5.1 m/sec(2).

CONCLUSION

The findings suggest an important potential role for duplex US in noninvasive assessment of the immediate hemodynamic outcome and long-term follow-up of PTRAS.

"Practicing" medicine without risk: students' and educators' responses to high-fidelity patient simulation

PURPOSE

To understand the responses of medical students and educators to high-fidelity patient simulation, a new technology allowing "practice without risk."

METHOD

Pilot groups of students (n = 27) and educators (n = 33) were exposed to a simulator session, then surveyed with multiple-choice and open-ended questions. Open-ended comments were transcribed and coded. They were analyzed for recurring themes and tested for inter-rater agreement. An independent focus group subsequently performed higher-level thematic analysis.

RESULTS

Overall, 85% of the students rated the session excellent and 85% of the educators rated it excellent or very good. Over 80% of both groups thought that simulator-based training should be required for all medical students. Analytic categories derived from written comments were: Overall Assessment (i.e., "generally good experience"); Process Descriptors (i.e., "very realistic"); Teaching Utility (i.e., "broad educational tool"); Pedagogic Efficacy (i.e., "promotes critical thinking"); and Goals for Future Use (i.e., "more practice sessions"). Thirty percent of students and 38% of educators were impressed by the realism of the simulator, and they (37% and 25%, respectively) identified the ability to "practice" medicine as the primary advantage of simulation. The focus group rated cost as the major current disadvantage (66%).

CONCLUSIONS

Students' and educators' responses to high-fidelity patient simulation were very positive. The ability to practice without risk must be weighed against the cost of this new technology.

Employer strategies for modifying or terminating retiree benefits in the 1990s

Over the past decade, access to health care coverage has become a crucial national concern. At the same time, the rising cost of health care, the aging of the population, and new accounting requirements for retiree medical benefits have caused employers to reevaluate their commitment to providing unrestricted health care benefits to the retirees. This article discusses the key federal appellate court decisions concerning an employer's decision to modify or terminate retiree medical benefits. It then explores alternatives for meeting the statutory, legal, and accounting challenges faced by employers who now offer retiree health care coverage.

Where health and welfare meet: social deprivation among patients in the emergency department

CONTEXT

As a safety net provider for many disadvantaged Americans, the emergency department (ED) may be an efficient site not only for providing acute medical care, but also for addressing serious social needs.

OBJECTIVE

To characterize the social needs of ED patients, and to evaluate whether the most disadvantaged patients have connections with the health and welfare system outside the ED.

DESIGN

Cross-sectional survey conducted over 24 hours in the fall of 1997.

SETTING

Three EDs: an urban public teaching hospital, a suburban university hospital, and a semirural community hospital.

PARTICIPANTS

Consecutive patients presenting for care, including those transported by ambulance. The survey response rate was 91% (N = 300; urban = 115, suburban = 102, rural = 83).

MAIN OUTCOME MEASURE

Index of socioeconomic deprivation described by the US Census Bureau (based on food, housing, and utilities).

RESULTS

Of all ED patients, 31% reported one or more serious social deprivations. For example, 13% of urban patients reported not having enough food to eat, and 9% of rural patients reported disconnection of their gas or electricity (US population averages both less than 3%). While 40% of all patients had no consistent health care outside the ED (< or = 1 visit/year), those with higher levels of social deprivation had the least contact with the health care system outside the ED (P < .01). Although those with higher levels of deprivation were more likely to receive public assistance, still almost one-quarter of patients with high-level social deprivation were not receiving public aid.

CONCLUSION

Many ED patients suffer from fundamental social deprivations that threaten basic health. The most disadvantaged of these patients frequently lack contact with other medical care sites or public assistance networks. Community efforts to address serious social deprivation should include partnerships with the local ED.

Plaque mineral induction and inhibition properties in the formation of supragingival calculus

Several individual species of dental plaque bacteria have the ability to initiate the precipitation of calcium phosphate minerals in vitro; other plaque components have been shown to inhibit mineralisation. We have examined subjects' overall plaque mineralisation promoter and inhibitor properties, and have attempted to correlate them with supragingival calculus development over 6 months. Three-day-old plaque was collected from 22 adult subjects at the start and end of the study. To detect promoter activity, the plaque was placed in a suspension of brushite, the liquid phase of which was supersaturated with respect to hydroxyapatite. The extent of mineralisation was determined by the rise in phosphate concentration over 4 days. To detect inhibitor activity, plaque was placed in a similar suspension, which also contained hydroxyapatite. Promoter activity was compared with that hydroxyapatite, and inhibitor activity was compared with polyaspartate. The subjects' teeth were scaled at the start of the study, and calculus deposition was measured at the end using the Volpe Manhold method. Most plaque samples showed some promoter or inhibitor activity, or both, but no significant correlation existed between these activities and a subject's development of calculus. A significant inverse correlation existed between plaque mineralisation promoter activity and its inhibitor activity at the start of the study. Our results suggest that the nucleating and mineralisation inhibitory properties of young plaque will probably not be a useful target for a practical preventive methodology for supragingival calculus.

Cost-benefit analysis of social work services in the emergency department: a conceptual model

OBJECTIVE

To describe an economic model for formal cost-benefit analysis of emergency department (ED)-based social services.

METHODS

The varied monetary costs and benefits associated with ED-based social work services were projected for three hypothetical levels of ED volume (30,000, 60,000, and 90,000 patients/year). Primary benefits included the prevention of return ED visits, the prevention of "social" hospital admissions, and the protection of doctor and nurse time. The primary cost was salary support for full-time social work staffing. Sensitivity analysis was performed to account for varying estimates.

RESULTS

For a small-volume ED, total benefits to offset costs ranged from $43,869 to $81,504, yielding a net cost of $99,936 up to $137,571 for full-time social work coverage. For a moderate-size ED, total benefits ranged from $87,660 to $162,930, yielding a net cost of only $18,510 on the high end of the sensitivity analysis, and $87,668 on the low end. For a large-volume ED, total benefits ranged from $131,529 to $247,434, yielding a net cost of $49,911 on the low end of the sensitivity analysis, but a net benefit of $65,994 on the high end.

CONCLUSIONS

Dedicated social work staffing of EDs may yield net economic benefits, especially in large urban centers. Moderate-size EDs may almost "break even" in economic terms, and small EDs may realize a net cost, but in either case, the cost of social services can be significantly offset by decreased utilization of hospital and ED services, and by more efficient use of medical staff time.

Preventive care in the emergency department, Part I: Clinical preventive services--are they relevant to emergency medicine? Society for Academic Emergency Medicine Public Health and Education Task Force Preventive Services Work Group

In 1998 the Society for Academic Emergency Medicine's (SAEM's) Board of Directors asked the SAEM Public Health and Education Task Force to develop recommendations for prevention, screening, and counseling activities to be conducted in emergency departments (EDs). The Task Force's work was divided into two phases: 1) a discussion of the rationale for preventive services in the ED, along with generation of a preliminary list of prevention activities that could be studied for ED implementation; and 2) a formal evidence-based review of topics chosen from the preliminary list, along with recommendations for ED implementation and further study. This paper represents Phase I of the project. Phase II, the formal evidence-based review and recommendations, is published separately in this issue.

Modified intranuclear organization of regulatory factors in human acute leukemias: reversal after treatment

Acute leukemias arise secondary to chromosomal aberrations that cause dysfunctions in gene regulation and regulatory factors. Significant differences in morphology between acute leukemic and nonleukemic hematopoietic cells are readily observed. How morphologic changes of the nuclei of acute leukemic cells relate to the underlying functional alterations of gene expression is minimally understood. Spatial modifications in the representation and/or organization of regulatory factors may be functionally linked to perturbations of gene expression in acute leukemic cells. Using in situ immunofluorescence microscopy, we addressed the interrelationships of modifications in nuclear morphology with the intranuclear distribution of leukemia-related regulatory factors (including ALL-1, PML, and AF-9) in cells from patients with acute leukemia. We compared the localization of leukemia-associated proteins with various factors involved in gene transcription and RNA processing (e.g., RNA polymerase II and SC-35). Our findings suggest that there are leukemia-associated aberrations in mechanisms that direct regulatory factors to sites within the nucleus. This misplacement of key cognate factors may contribute to perturbations in gene expression characteristic of leukemias.

The hospital emergency department as a social welfare institution

In an era of social welfare reform marked by the erosion of a societal safety net, few institutions remain that can guarantee assistance to those most in need. The hospital emergency department is perhaps the only local institution where professional help is mandated by law, with guaranteed availability for all persons, all the time, regardless of the problem. Although the ED serves as a true social safety net, its potential as a social welfare institution generally goes underestimated, hampering its full development as an effective societal resource. More of the disadvantaged may pass through the ED than through any other community institution, making it a logical site not only for the treatment of acute illness, but also for the identification of basic social needs and the extension of existing community resources. By helping more fully incorporate the ED into the total care of its community, emergency physicians can become leaders in the design and implementation of integrated sociomedical systems of care.

Initial emergency department diagnosis and return visits: risk versus perception

STUDY OBJECTIVES

To identify diagnostic predictors of return emergency department visits, and to compare actual and perceived associations between initial ED diagnosis and revisits to help identify target diagnoses for prevention strategies.

METHODS

This 2-part study involved a retrospective observational study and a health professional survey. The study population consisted of all patients with 2 or more visits to the University of Michigan ED within a 3-day period between July 1995 and June 1996 ("early-return visitors"). Billing records identified the initial diagnoses of subsequent return visitors. The prevalence of each initial diagnosis was determined in the general ED population (n=52,553), early-return population (n=1,422), and early-return population admitted to the hospital ("return-admit," n=313). Surveys were distributed to all ED health professionals to assess their perception of the diagnoses most likely to return within 3 days. Relative risk (RR) ratios and 95% confidence intervals (CIs) were calculated.

RESULTS

Dehydration was the most common diagnosis in the general, early-return, and return-admit populations (prevalence: 7%, 15%, 25%, respectively). Dehydration was also the diagnosis with the highest risk for both early return and subsequent admission on early return (RR [95% CI]: 2.3 [2.0-2.6], 1.8 [1.5-2.3], respectively). Nearly two thirds of health professionals, however, did not identify dehydration as a diagnosis at high risk for return, and almost half did not consider dehydration a high risk for admission.

CONCLUSION

Initial ED diagnosis may be a useful predictor of early ED return and admission. Patients with an initial diagnosis of dehydration are at particularly high risk for early return and admission, yet providers underestimate the risk in this very common group. Screening a return ED population for high-frequency diagnoses may reveal underrecognized target groups for specific prevention strategies.

Comparison of plasticity in vivo and in vitro in the developing visual cortex of normal and protein kinase A RIbeta-deficient mice

Developing sensory systems are sculpted by an activity-dependent strengthening and weakening of connections. Long-term potentiation (LTP) and depression (LTD) in vitro have been proposed to model this experience-dependent circuit refinement. We directly compared LTP and LTD induction in vitro with plasticity in vivo in the developing visual cortex of a mouse mutant of protein kinase A (PKA), a key enzyme implicated in the plasticity of a diverse array of systems. In mice lacking the RIbeta regulatory subunit of PKA, we observed three abnormalities of synaptic plasticity in layer II/III of visual cortex in vitro. These included an absence of (1) extracellularly recorded LTP, (2) depotentiation or LTD, and (3) paired-pulse facilitation. Potentiation was induced, however, by pairing low-frequency stimulation with direct depolarization of individual mutant pyramidal cells. Together these findings suggest that the LTP defect in slices lacking PKA RIbeta lies in the transmission of sufficient net excitation through the cortical circuit. Nonetheless, functional development and plasticity of visual cortical responses in vivo after monocular deprivation did not differ from normal. Moreover, the loss of all responsiveness to stimulation of the originally deprived eye in most cortical cells could be restored by reverse suture of eyelids during the critical period in both wild-type and mutant mice. Such an activity-dependent increase in response would seem to require a mechanism like potentiation in vivo. Thus, the RIbeta isoform of PKA is not essential for ocular dominance plasticity, which can proceed despite defects in several common in vitro models of neural plasticity.

Cellular mechanisms of visual cortical plasticity: a game of cat and mouse

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Conversion of arachidonic acid to tetradecadienoic acid by peroxisomal oxidation

Human skin fibroblasts convert [5,6,8,9,11,12,14,15-3H]arachidonic acid to two radiolabeled polar metabolites that accumulate in the culture medium. Previous studies identified the most abundant of these products as 4,7,10-hexadecatrienoic acid (16:3). We have now identified the second metabolite as 5,8-tetradecadienoic acid (14:2). Fibroblasts deficient in mitochondrial long-chain acyl coenzyme A dehydrogenase produce increased amounts of 14:2 from arachidonic acid. By contrast, Zellweger fibroblasts which are deficient in peroxisomal beta-oxidation do not convert arachidonic acid to either 14:2 or 16:3. These results demonstrate that 14:2 can be synthesized from arachidonic acid, that this oxidative process occurs in the peroxisomes, and that the pathway does not function in Zellweger's syndrome and similar diseases where there is a genetic deficiency in peroxisomal beta-oxidation.

Deficient plasticity in the primary visual cortex of alpha-calcium/calmodulin-dependent protein kinase II mutant mice

The recent characterization of plasticity in the mouse visual cortex permits the use of mutant mice to investigate the cellular mechanisms underlying activity-dependent development. As calcium-dependent signaling pathways have been implicated in neuronal plasticity, we examined visual cortical plasticity in mice lacking the alpha-isoform of calcium/calmodulin-dependent protein kinase II (alpha CaMKII). In wild-type mice, brief occlusion of vision in one eye during a critical period reduces responses in the visual cortex. In half of the alpha CaMKII-deficient mice, visual cortical responses developed normally, but visual cortical plasticity was greatly diminished. After intensive training, spatial learning in the Morris water maze was severely impaired in a similar fraction of mutant animals. These data indicate that loss of alpha CaMKII results in a severe but variable defect in neuronal plasticity.

Experience-dependent plasticity of binocular responses in the primary visual cortex of the mouse

An activity-dependent form of synaptic plasticity underlies the fine tuning of connections in the developing primary visual cortex of mammals such as the cat and monkey. Studies of the effects of manipulations of visual experience during a critical period have demonstrated that a correlation-based competitive process governs this plasticity. The cellular mechanisms underlying this competition, however, are poorly understood. Transgenic and gene-targeting technologies have led to the development of a new category of reagents that have the potential to help answer questions of cellular mechanism, provided that the questions can be studied in a mouse model. The current study attempts to characterize a developmental plasticity in the mouse primary visual cortex and to demonstrate its relevance to that found in higher mammals. We found that 4 d of monocular lid suture at postnatal day 28 (P28) induced a maximal loss of responsiveness of cortical neurons to the deprived eye. These ocular dominance shifts occurred during a well-defined critical period, between P19 and P32. Furthermore, binocular deprivation during this critical period did not decrease visual cortical responses, and alternating monocular deprivation resulted in a decrease in the number of binocularly responsive neurons. Finally, a laminar analysis demonstrated plasticity of both geniculocortical and intracortical connections. These results demonstrate that an activity-dependent, competitive form of synaptic plasticity that obeys correlation-based rules operates in the developing primary visual cortex of the mouse.

The impact of immunosuppressive regimens on the cost of liver transplantation--results from the U.S. FK506 multicenter trial

In an effort to determine the total one-year cost of liver transplantation, the underlying drivers of that cost, and any cost differences between alternative immunosuppressive regimens, an analysis was performed comparing the average one-year posttransplant charges of 322 patients participating in the "U.S. Multi-center Prospective Randomized Trial Comparing FK-506 to Cyclosporine in Liver Transplantation." Total one-year inpatient charges including all readmissions were examined. Professional fees and outpatient charges were excluded. Costs for tacrolimus drug and blood assays were assumed to be equal to those in the CsA group. For patients completing the study, the tacrolimus group had an average length of stay and average one-year cost seven days (P = .06) and $19,290 (P = .05) lower than the CsA group. The difference in rejection profiles between the two arms seems to largely account for the lower costs. The tacrolimus arm consistently had fewer patients in the more severe rejection groups. Increased incidence and severity of rejection were directly related to higher average lengths of stay and costs of transplantation (P < .001). Tacrolimus immunosuppression during the first year after liver transplantation is more cost-effective than CsA in achieving similar patient and graft survival rates. Differing incidence and severity of rejection can dramatically affect the first-year cost of liver transplantation.

Delayed suprachoroidal hemorrhage mimicking acute retrobulbar hemorrhage

The signs and symptoms of an acute retrobulbar hemorrhage include sudden ocular pain, explosive unilateral proptosis, limitation of extraocular movements and loss of vision. Retrobulbar hemorrhage is a well-described complication of retrobulbar anesthetic injection. We report an unusual case of a presumed acute retrobulbar hemorrhage following intraocular surgery which, on further testing, was found to be a delayed suprachoroidal hemorrhage.

Regulation of differentiation of peritoneal B-1a (CD5+) B cells. Activated peritoneal macrophages release prostaglandin E2, which inhibits IgM secretion by peritoneal B-1a cells

The B-1a (CD5+) subset of B cells comprises the majority of B cells in the peritoneal cavity and is implicated in the pathogenesis of certain autoimmune diseases and lymphoproliferative disorders. When we stimulated purified B-1a cells with LPS, they produced more than four times as much IgM as similarly stimulated whole peritoneal cells (containing the same number of B-1a cells). Reconstitution experiments using FACS-purified peritoneal cell populations revealed that resident peritoneal macrophages (Mac1+, B220-) profoundly inhibited the LPS response of peritoneal B-1a cells. Culture of B-1a cells with peritoneal macrophages at a ratio of 3:1 (reflecting the in vivo ratio) resulted in a fivefold or greater reduction in the IgM response to LPS. LPS activation of macrophages resulted in production of a soluble factor that inhibited LPS-induced B cell differentiation by 86% when used at a concentration of 5%. When [3H]arachidonic acid-pulsed macrophages were stimulated with LPS, the major arachidonic acid metabolite secreted was PGE2 (a potent inhibitor of B cell differentiation). The inhibitory capacity of the macrophage-derived supernatant was reversed by the addition of anti-PGE2. These findings indicate that macrophage-derived PGE2 functions as an important regulator of polyclonal response of B-1a cells to LPS.

Regulation of differentiation of peritoneal B-1a (CD5+) B cells. Activated peritoneal macrophages release prostaglandin E2, which inhibits IgM secretion by peritoneal B-1a cells

The B-1a (CD5+) subset of B cells comprises the majority of B cells in the peritoneal cavity and is implicated in the pathogenesis of certain autoimmune diseases and lymphoproliferative disorders. When we stimulated purified B-1a cells with LPS, they produced more than four times as much IgM as similarly stimulated whole peritoneal cells (containing the same number of B-1a cells). Reconstitution experiments using FACS-purified peritoneal cell populations revealed that resident peritoneal macrophages (Mac1+, B220-) profoundly inhibited the LPS response of peritoneal B-1a cells. Culture of B-1a cells with peritoneal macrophages at a ratio of 3:1 (reflecting the in vivo ratio) resulted in a fivefold or greater reduction in the IgM response to LPS. LPS activation of macrophages resulted in production of a soluble factor that inhibited LPS-induced B cell differentiation by 86% when used at a concentration of 5%. When [3H]arachidonic acid-pulsed macrophages were stimulated with LPS, the major arachidonic acid metabolite secreted was PGE2 (a potent inhibitor of B cell differentiation). The inhibitory capacity of the macrophage-derived supernatant was reversed by the addition of anti-PGE2. These findings indicate that macrophage-derived PGE2 functions as an important regulator of polyclonal response of B-1a cells to LPS.

Formation of a novel arachidonic acid metabolite in peroxisomes

A new radiolabeled metabolite was released into the extracellular fluid by normal human skin fibroblasts that were labeled with [5,6,8,9,11,12,14,15-3H] arachidonic acid. This product continued to accumulate during a 24 h incubation, and its formation was not saturated at arachidonic acid concentrations up to 15 mumol/L. The compound, identified as hexadecatrienoic acid, was not produced by Zellweger fibroblasts which are deficient in peroxisomal fatty acid beta-oxidation. By contrast, radiolabeled hexadecatrienoic acid was produced by mutant fibroblasts having other peroxisomal defects, including X-linked adrenoleukodystrophy, adult Refsum's disease, and rhizomelic chondrodysplasia punctata. This radiolabeled metabolite also was produced by mutant fibroblasts that cannot oxidize long-chain fatty acids in the mitochondria. These results indicate that hexadecatrienoic acid is synthesized from arachidonic acid by peroxisomal beta-oxidation. The absence of this pathway may account for some of the biochemical and functional abnormalities that occur in Zellweger's syndrome.

The new simplified Sim-Gordon orthodontic analysis

The new Sim-Gordon Computerized Analysis is simple to use, basic in the orthodontic diagnostic values that need to be measured and entered, and serves as an extremely useful guide for the treatment planning of orthodontic patients. It will run on any IBM compatible computer, and uses less than 740 Kb of space on a disk. So far as is known, all insurance companies will accept it. It is a pleasure to announce the availability of this reasonable and cost-effective, simplified, IAO-accepted, professional orthodontic diagnostic system to our fellow practitioners. The authors would like to thank Dr. Duane Keller, Dr. Yosh Jefferson, Dr. Thomas Hughes, Dr. Rudy Postema, Dr. Michel Champagne, Dr. John Byland, Dr. Kenneth Lyle, and Dr. Janet Doerr for their helpful suggestions and aid in the selection of values to be measured.

Understanding and treating Bartter syndrome

Most of its clinical manifestations are the result of hypokalemia. The diagnosis is one of exclusion, mainly of surreptitious vomiting and diuretic abuse. The primary cause remains unknown but the most likely candidate is reduced sodium chloride reabsorption in the thick ascending limb of Henle's loop. Current therapy focuses on multiple agents to reduce massive potassium loss.

Mitochondrial metabolism of 12- and 15-hydroxyeicosatetraenoic acids

We have previously demonstrated that peroxisomal-deficient human skin fibroblasts and mutant Chinese hamster ovary cells do not convert 12- and 15-hydroxyeicosatetraenoic acids (HETEs) to chain-shortened, polar metabolites, suggesting that peroxisomes are the intracellular location for beta-oxidation of these compounds. This implies that mitochondria do not beta-oxidize HETEs. To test this hypothesis we incubated highly purified rat liver mitochondria with [3H]12-(S)- and [3H]15-(S)-HETE in the presence of carnitine and an acylcoenzyme A-generating system. Extracts obtained from these incubations were analyzed for radiolabeled polar metabolites. Both HETEs were converted to apparent products of beta-oxidation, although the 12-HETE compound was a markedly better substrate. The presence of 50 microM 2-tetradecyloxirane carboxylate, a potent inhibitor of carnitine palmitoyl transferase, completely blocked 12- and 15-HETE conversion to these metabolites as did omission of carnitine from the medium. These data demonstrate carnitine-dependent beta-oxidation of HETEs in isolated mitochondria and suggest that mitochondria are competent to carry out this metabolic process in eukaryotic cells. Prevailing metabolic conditions in subcellular compartments may have precluded observation of mitochondrial activity in our earlier work with cultured cells. Alternatively, transport mechanisms may exist in the cell types studied that distribute 12-(S)- and 15-(S)-HETEs specifically to peroxisomes.

15-HETE: selective incorporation into inositol phospholipids of MDCK cells

The interaction of 15-hydroxyeicosatetraenoic acid (15-HETE) and cultured MDCK renal tubular epithelial cells was investigated to determine whether incorporation of this lipoxygenase product will affect polyphosphoinositide formation. MDCK cells were incubated with 1 microM [3H]-15-HETE for 15 to 120 minutes. Maximum uptake occurred between 15 and 30 minutes, and after 60 minutes, 70% of the incorporated 15-HETE was present in the phosphatidylinositol (PI) fraction. Some 15-HETE was also incorporated into phosphatidylinositol-4-monophosphate (PIP) and phosphatidylinositol-4,5-bisphosphate (PIP2). However, even though more 15-HETE than arachidonic acid was incorporated into PI, the fractional amount of 15-HETE present in the polyphosphoinositides was smaller than arachidonic acid. Therefore, although 15-HETE is selectively channeled into PI, conversion of PI species containing 15-HETE to PIP and PIP2 is relatively impaired. This suggests that either PI containing 15-HETE is a less effective substrate for phosphorylation, or PI containing arachidonic acid is a preferred substrate. MDCK cells converted 15-HETE to polar metabolites that were released into the extracellular fluid. This process may constitute a renal tubular mechanism for the clearance of 15-HETE and related lipoxygenase products.

Formation and release of a peroxisome-dependent arachidonic acid metabolite by human skin fibroblasts

Human skin fibroblasts labeled with [5,6,8,9,11,12,-14,15-3H]arachidonic acid produce a radioactive metabolite that has a shorter retention time on reverse-phase high-performance liquid chromatography than arachidonic acid. This product is not retained in the cells; it is released entirely into the extracellular fluid in a time-dependent manner. The metabolite does not cochromatograph with any of the eicosanoid standards, and its formation is not prevented by the addition of cyclooxygenase, lipoxygenase, or cytochrome P-450 inhibitors. The compound is not produced by fibroblasts labeled with [1-14C]arachidonic acid, suggesting that it is formed through an oxidative process. Chemical analyses indicated that the metabolite is 4,7,10-hexadecatrienoic acid (16:3). Peroxisome-deficient human skin fibroblasts did not produce 16:3, indicating that it probably is formed through peroxisomal beta-oxidation. Human umbilical vein endothelial cells and porcine pulmonary artery smooth muscle cells also release radioactive 16:3 following labeling with [3H]arachidonic acid. Therefore, the production of this metabolite is not limited only to fibroblasts. The fact that 16:3 is released into the extra-cellular fluid suggests that it may be a new type of lipid mediator derived from arachidonic acid, formed through a peroxisome-dependent oxidative process.

Attenuated prostaglandin formation in peroxisomal-deficient human skin fibroblasts

Peroxisomal-deficient skin fibroblasts from patients with Zellweger's syndrome or infantile Refsum's disease produced fewer prostaglandins than normal skin fibroblasts. Radioimmunoassay indicated a 45-55% decrease in prostaglandin E2 (PGE2) production when Zellweger's fibroblasts were incubated with arachidonic acid. This deficiency was not overcome by pretreatment of the Zellweger's fibroblasts with media containing arachidonic acid, and it was not due to channeling of arachidonic acid into other eicosanoid products. Modifications in the peroxide tone of the Zellweger's fibroblasts by addition of H2O2 or catalase failed to increase PGE2 production. Using Northern analysis, we were unable to detect an mRNA transcript for PGH synthase in unstimulated Zellweger fibroblasts but identified a 4.2-kb mRNA transcript after treatment with phorbol myristate acetate (PMA). Treatment for 6 h with 10 nM PMA raised PGE2 production in normal and Zellweger fibroblasts to equivalent levels. These increases were prevented by addition of H-7, staurosporine, cycloheximide, or actinomycin D. Our findings suggest that the reduced PGE2 production in peroxisomal deficient fibroblasts is due to a decrease in PGH synthase mRNA. The reduction in PGH synthase can be overcome by treatment of the cells with agents which enhance gene expression.

Thrombotic microangiopathy: a case report and review of the literature

Thrombotic microangiopathy most likely represents a spectrum of diseases consisting of multiple etiologies that has a final common pathway of multiorgan microvascular thrombosis. The variable responses to several different modes of therapy would suggest that more than one pathogenetic mechanism is involved. Untreated, it has been associated with very high morbidity and mortality rates. A poor understanding of the basic disease process has prevented specific treatment modalities, although early diagnosis and availability of dialysis and blood product transfusion services remain crucial. Several modes of therapy have been used to date, with plasma exchange being the most effective method studied and shown to improve survival. On the basis of current knowledge, this form of treatment should be instituted promptly in severe cases. Anecdotal reports of recovery with vincristine or IgG alone or with the use of IgG after the apparent failure of plasma therapy appear promising and deserve further investigation as initial therapeutic measures used in thrombotic microangiopathy. Although the majority of patients recover with normal renal function, those with severe thrombotic microangiopathy may heal through sclerosis with residual hypertension and chronic renal impairment requiring continual medical therapy.