Induction of neuronal apoptosis by thiol oxidation: putative role of intracellular zinc release

The membrane-permeant oxidizing agent 2,2'-dithiodipyridine (DTDP) can induce Zn(2+) release from metalloproteins in cell-free systems. Here, we report that brief exposure to DTDP triggers apoptotic cell death in cultured neurons, detected by the presence of both DNA laddering and asymmetric chromatin formation. Neuronal death was blocked by increased extracellular potassium levels, by tetraethylammonium, and by the broad-spectrum cysteine protease inhibitor butoxy-carbonyl-aspartate-fluoromethylketone. N,N,N', N'-Tetrakis-(2-pyridylmethyl)ethylenediamine (TPEN) and other cell-permeant metal chelators also effectively blocked DTDP-induced toxicity in neurons. Cell death, however, was not abolished by the NMDA receptor blocker MK-801, by the intracellular calcium release antagonist dantrolene, or by high concentrations of ryanodine. DTDP generated increases in fluorescence signals in cultured neurons loaded with the zinc-selective dye Newport Green. The fluorescence signals following DTDP treatment also increased in fura-2- and magfura-2-loaded neurons. These responses were completely reversed by TPEN, consistent with a DTDP-mediated increase in intracellular free Zn(2+) concentrations. Our studies suggest that under conditions of oxidative stress, Zn(2+) released from intracellular stores may contribute to the initiation of neuronal apoptosis.

Nosocomial septicemia due to multiply antibiotic-resistant Staphylococcus epidermidis

Thirteen episodes of Staphylococcus epidermidis sepsis occurred over a 20-month period in 11 patients receiving general surgical and medical care. These episodes were characterized by fever, toxicity, multiple positive blood cultures, and uniformly colonized intravascular catheters. An additional 16 patients had possible sepsis. Four associated deaths occurred; all three patients autopsied had multiple pulmonary abscesses in which gram-positive cocci were profusely present. In individual patients, prolonged episodes of septicemia were confirmed by multiple blood culture isolates of S. epidermidis, identical in antibiotic resistance pattern, phage type, and biotype. A prominent feature of the S. epidermidis isolates was resistance to many commonly used antimicrobial agents. Case-control studies and review of laboratory records indicated a significant association between multiply resistant S. epidermidis blood isolates and prolonged hospitalization and parenteral hyperalimentation. Most of these patients were hospitalized in the intensive care unit; nose and hand cultures taken from the personnel showed frequent carriage of multiply resistant S. epidermidis Staphylococcus epidermidis associated with intravascular devices may produce life-threatening bloodstream infections.

Levels of endothelial cell stimulating angiogenesis factor and vascular endothelial growth factor are elevated in psoriasis

Neovascularization appears to play an early and important part in the evolution of psoriatic plaques. We studied the distribution and production of two known angiogenesis factors, endothelial cell stimulating angiogenesis factor (ESAF) and vascular endothelial growth factor (VEGF), in the skin of patients with chronic plaque psoriasis and normal control subjects. Our results showed that tissue levels of ESAF and VEGF were significantly elevated in involved as compared with normal control skin (P = 0.006 and P < 0. 0001, respectively). Tissue levels of ESAF and VEGF were also raised in involved skin as compared with uninvolved skin in patients with psoriasis (P = 0.001 and P < 0.0001, respectively). Tissue levels of ESAF and VEGF in plaques of psoriasis correlated closely with the clinical severity of psoriasis (r = 0.6 and r = 0.9, respectively). Serum levels of ESAF and VEGF were significantly raised in patients with psoriasis as compared with control subjects (P = 0.001 and P = 0.02, respectively). In vitro culture studies revealed that ESAF is produced by both keratinocytes and fibroblasts in approximately equal quantities in normal skin, whereas VEGF is secreted predominately by keratinocytes. A similar pattern is seen in both involved and uninvolved skin of patients with psoriasis. However, there is increased secretion of both factors in keratinocytes and fibroblasts from involved and uninvolved skin as compared with normal control skin (P < 0.001). The increased levels and secretion in plaques of psoriasis of two molecules, ESAF and VEGF, known to promote new blood vessel formation, suggest a pathogenetic role for them in this disease.

Hydrologic refugia, plants, and climate change

Climate, physical landscapes, and biota interact to generate heterogeneous hydrologic conditions in space and over time, which are reflected in spatial patterns of species distributions. As these species distributions respond to rapid climate change, microrefugia may support local species persistence in the face of deteriorating climatic suitability. Recent focus on temperature as a determinant of microrefugia insufficiently accounts for the importance of hydrologic processes and changing water availability with changing climate. Where water scarcity is a major limitation now or under future climates, hydrologic microrefugia are likely to prove essential for species persistence, particularly for sessile species and plants. Zones of high relative water availability - mesic microenvironments - are generated by a wide array of hydrologic processes, and may be loosely coupled to climatic processes and therefore buffered from climate change. Here, we review the mechanisms that generate mesic microenvironments and their likely robustness in the face of climate change. We argue that mesic microenvironments will act as species-specific refugia only if the nature and space/time variability in water availability are compatible with the ecological requirements of a target species. We illustrate this argument with case studies drawn from California oak woodland ecosystems. We posit that identification of hydrologic refugia could form a cornerstone of climate-cognizant conservation strategies, but that this would require improved understanding of climate change effects on key hydrologic processes, including frequently cryptic processes such as groundwater flow.

The role of clinical opinion leaders in guideline implementation and quality improvement

BACKGROUND

The lag between the publication of clinical and health-services research and the application of this information is substantial and delays health-care improvement. A wide range of corrective strategies are being used to address this issue.

OBJECTIVES

Evolution in the use of significant opinion leaders is described. Hospital quality improvement projects, undertaken by the Healthcare Education and Research Foundation (HERF), are used to illustrate the roles assumed by clinical opinion leaders. Specific theoretical frameworks are reviewed that are fundamental to successful implementation of opinion leader strategies, as well as key research on the use of clinical opinion leaders.

RESULTS

Over the past 12 years, HERF has identified the need to address not only the information needs of clinicians and organizations but also the social and organizational factors that interfere with the application of research and guidelines. The complexity of this task cannot be underestimated. However, armed with well-developed guidelines and the opportunity to work within structured guideline implementation programs with well-defined objectives and systematically applied methods, HERF's experience suggest local clinicians and communities can meet this challenge.

Newborn minor physical anomalies predict short attention span, peer aggression, and impulsivity at age 3

From a 5-to 10-minute newborn examination, behaviors of males at age 3 could be predicted. The number of minor physical anomalies, assessed soon after birth, was significantly related to a cluster of behaviors that are frequently labeled hyperactivity.

The kinder side of killer proteases: caspase activation contributes to neuroprotection and CNS remodeling

Caspases are a family of cysteine proteases that are expressed as inactive zymogens and undergo proteolytic maturation in a sequential manner in which initiator caspases cleave and activate the effector caspases 3, 6 and 7. Effector caspases cleave structural proteins, signaling molecules, DNA repair enzymes and proteins which inhibit apoptosis. Activation of effector, or executioner, caspases has historically been viewed as a terminal event in the process of programmed cell death. Emerging evidence now suggests a broader role for activated caspases in cellular maturation, differentiation and other non-lethal events. The importance of activated caspases in normal cell development and signaling has recently been extended to the CNS where these proteases have been shown to contribute to axon guidance, synaptic plasticity and neuroprotection. This review will focus on the adaptive roles activated caspases in maintaining viability, the mechanisms by which caspases are held in check so as not produce apoptotic cell death and the ramifications of these observations in the treatment of neurological disorders.

Epidemic Serratia marcescens in a neonatal intensive care unit: importance of the gastrointestinal tract as a reservoir

Between a March and December of 1979, and outbreak of infections due to multiply antibiotic resistant Serratia marcescens took place in a 50-bed neonatal intensive care unit. Fifteen neonates suffered major infections (sepsis, meningitis and pneumonia) with one death, and 20 suffered minor infections (conjunctivitis, cystitis, wound infections). Epidemiologic investigation failed to reveal a common source; S. marcescens, however, ws isolated from an employee's hand, emollient skin cleanser, suction tubing, and three in-use manual infant resuscitation bags. The skin cleanser and equipment-cleaning agents were ineffective against S. marcescens. Asymptomatic, colonized infants were the major reservoir of S marcescens. These infants were identified by daily cultures of the nose, umbilicus and rectum. The rectal swab most commonly (76%) yielded first-positive cultures in previously uncolonized infants, and was ultimately positive in 92% of colonized infants. A control program was begun by: 1) removing all inanimate sources of S. marcescens; and 2) cohorting patients and staff into a S. marcescens-exposed group and a new patient group. The new patient group of infants was surveyed by daily triple-site cultures for colonization and subsequent transfer to the S. marcescens-exposed group. After four months, the epidemic was controlled and the organism eradicated from the neonatal intensive care unit.

Consultation between cardiologists and generalists in the management of acute myocardial infarction: implications for quality of care

BACKGROUND

The rapid expansion of managed care in the United States has increased debate regarding the appropriate mix of generalist and specialist involvement in medical care.

OBJECTIVE

To compare the quality of medical care when generalists and cardiologists work separately or together in the management of patients with acute myocardial infarction (AMI).

METHODS

We reviewed the charts of 1716 patients with AMI treated at 22 Minnesota hospitals between 1992 and 1993. Patients eligible for thrombolytic aspirin, beta-blockers, and lidocaine therapy were identified using criteria from the 1991 American College of Cardiology guidelines for the management of AMI. We compared the use of these drugs among eligible patients whose attending physician was a generalist with no cardiologist input, a generalist with a cardiologist consultation, and a cardiologist alone.

RESULTS

Patients cared for by a cardiologist alone were younger, presented earlier to the hospital, were more likely to be male, had less severe comorbidity, and were more likely to have an ST elevation of 1 mm or more than generalists' patients. Controlling for these differences, there was no variation in the use of effective agents between patients cared for by a cardiologist attending physician and a generalist with a consultation by a cardiologist. However, there was a consistent trend toward increased use of aspirin, thrombolytics, and beta-blockers in these patients compared with those with a generalist attending physician only (P<.05 for beta-blockers only). Differences between groups in the use of lidocaine were not statistically significant. The adjusted probabilities of use of thrombolytics for consultative care and cardiologist attending physicians were 0.73 for both. Corresponding probabilities were 0.86 and 0.85 for aspirin and 0.59 and 0.57 for beta-blockers, respectively.

CONCLUSIONS

For patients with AMI, consultation between generalists and specialists may improve the quality of care. Recent policy debates that have focused solely on access to specialists have ignored the important issue of coordination of care between generalist and specialist physicians. In hospitals where cardiology services are available, generalists may be caring for patients with AMI who are older and more frail. Future research and policy analyses should examine whether this pattern of selective referral is true for other medical conditions.

Age-related differences in granulocyte chemotaxis and degranulation

In the present study we have demonstrated that human peripheral blood granulocytes from elderly subjects exhibit reduced chemotaxis and degranulation in response to stimulation with fMet-Leu-Phe. Cyclic AMP levels in non-stimulated cells were not significantly different (mean +/- SEM): 4.8 +/- 0.6 and 3.9 +/- 0.4 pmol/10(7) cells for young and elderly respectively. Stimulation with fMet-Leu-Phe (5 X 10(-7) mol/l) for 30s induced the production of cyclic AMP: 8.4 +/- 0.5 and 6.7 +/- 0.3 pmol/10(7) cells for young and elderly. These findings, together with those previously published by us, suggest that cyclic AMP production and cellular functions which this molecule participates in are reduced in cells from elderly individuals.

Simian virus 40-induced T and tumor antigens

Antigen extracts from simian virus 40 (SV40) transplanted hamster tumors were studied by rate-zonal centrifugation. Three species or molecular forms of antigen were demonstrated. The major antigen component corresponded to a molecular weight of 65,000 to 75,000, and two larger species were detectable in smaller quantities. Similar studies were carried out on SV40 virus-induced T antigen from BSC-1 cells. Three antigen components were again detected. Quantitative differences in the expression of "T" and tumor antigen species were reproducibly found.

Activation of a procollagenase by low-molecular-weight angiogenesis factor

Avascular tumours have the ability to establish a blood supply for themselves by secreting a humoral factor which stimulates their host's endothelial cells to proliferate and to migrate towards the tumour source. The mechanism of action of such a humoral angiogenesis factor is more than that of an endothelial-cell growth factor since it requires an oriented migration of cells towards the tumour. We report here the activation of pure skin-fibroblast procollagenase by a low-molecular-weight angiogenesis factor capable of stimulating endothelial-cell growth in vitro. The activation was observed when either Type I or III collagen was used as substrate. It is suggested that at least one function of angiogenesis factor is to promote limited degradation of the connective tissue through which it passes causing channeling in the matrix along which stimulated endothelial cells may migrate.

Beyond isohydricity: The role of environmental variability in determining plant drought responses

Despite the appeal of the iso/anisohydric framework for classifying plant drought responses, recent studies have shown that such classifications can be strongly affected by a plant's environment. Here, we present measured in situ drought responses to demonstrate that apparent isohydricity can be conflated with environmental conditions that vary over space and time. In particular, we (a) use data from an oak species (Quercus douglasii) during the 2012-2015 extreme drought in California to demonstrate how temporal and spatial variability in the environment can influence plant water potential dynamics, masking the role of traits; (b) explain how these environmental variations might arise from climatic, topographic, and edaphic variability; (c) illustrate, through a "common garden" thought experiment, how existing trait-based or response-based isohydricity metrics can be confounded by these environmental variations, leading to Type-1 (false positive) and Type-2 (false negative) errors; and (d) advocate for the use of model-based approaches for formulating alternate classification schemes. Building on recent insights from greenhouse and vineyard studies, we offer additional evidence across multiple field sites to demonstrate the importance of spatial and temporal drivers of plants' apparent isohydricity. This evidence challenges the use of isohydricity indices, per se, to characterize plant water relations at the global scale.

The hemolytic uremic syndrome associated with ECHO 22 infection

Serologic evidence for ECHO virus 22 was found in 8 of 10 patients with hemolytic uremic syndrome. The virus was isolated from the stools of two patients. All these patients also had gastroenteritis prior to the development of the syndrome. The results of this study indicate that ECHO 22 virus is an agent with a strong association with hemolytic uremic syndrome in pediatric patients.

Selective inhibitors of apoptotic caspases: implications for novel therapeutic strategies

Caspases are essential for apoptosis. A crucial question regarding the role(s) of these proteases is whether the selective inhibition of an effector caspase will prevent cell death. We have identified potent, selective non-peptide inhibitors of the effector caspases 3 and 7. Apoptosis can be inhibited and cell functionality maintained using an inhibitor selective for caspases 3 and 7. This has important therapeutic implications and the potential to generate novel anti-apoptotic strategies in diseases that involve dysregulated apoptosis.

Late onset adrenal hyperplasia in a group of Irish females who presented with hirsutism, irregular menses and/or cystic acne

The aims of this study were to determine the frequency of late-onset adrenal hyperplasia due specifically to 21-hydroxylase deficiency in a group of Irish women who presented at a Dublin Clinic with symptoms of hyperandrogenism, including hirsutism, menstrual irregularities and/or cystic acne, and to determine if those with 21-hydroxylase deficiency showed particular HLA associations. 119 women had blood samples taken basally and 1 h after an injection of 0.25 mg synacthen with the following hormones profiled: 17-hydroxyprogesterone, 11-deoxycortisol, androstenedione, testosterone, DHEAS and cortisol. Blood sampling was carried out between 0900 and 1000 h during the early follicular phase of the menstrual cycle (when applicable). Ninety-six subjects were new referrals to the Clinic for investigation of hyperandrogenism and 23 were acting as controls. In this study, 6% of patients showed evidence of partial 21-hydroxylase deficiency. In addition, 3 of the 6 with partial 21-hydroxylase deficiency had normal baseline levels of 17-hydroxyprogesterone, with the biochemical abnormality becoming manifest only on synacthen stimulation. Late-onset adrenal hyperplasia due to partial deficiency of this enzyme should always be considered as a possible diagnosis in women who present with symptoms of hyperandrogenism. Synacthen stimulation is an important diagnostic tool in elucidating partial enzyme deficiency as baseline 17-hydroxyprogesterone may be normal in such patients.

A cluster-randomized trial to improve stroke care in hospitals

OBJECTIVE

We evaluated the effect of performance feedback on acute ischemic stroke care quality in Minnesota hospitals.

METHODS

A cluster-randomized controlled trial design with hospital as the unit of randomization was used. Care quality was defined as adherence to 10 performance measures grouped into acute, in-hospital, and discharge care. Following preintervention data collection, all hospitals received a report on baseline care quality. Additionally, in experimental hospitals, clinical opinion leaders delivered customized feedback to care providers and study personnel worked with hospital administrators to implement changes targeting identified barriers to stroke care. Multilevel models examined experimental vs control, preintervention and postintervention performance changes and secular trends in performance.

RESULTS

Nineteen hospitals were randomized with a total of 1,211 acute ischemic stroke cases preintervention and 1,094 cases postintervention. Secular trends were significant with improvement in both experimental and control hospitals for acute (odds ratio = 2.7, p = 0.007) and in-hospital (odds ratio = 1.5, p < 0.0001) care but not discharge care. There was no significant intervention effect for acute, in-hospital, or discharge care.

CONCLUSION

There was no definite intervention effect: both experimental and control hospitals showed significant secular trends with performance improvement. Our results illustrate the potential fallacy of using historical controls for evaluating quality improvement interventions.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that informing hospital leaders of compliance with ischemic stroke quality indicators followed by a structured quality improvement intervention did not significantly improve compliance more than informing hospital leaders of compliance with stroke quality indicators without a quality improvement intervention.

Noise levels in a cardiac surgical intensive care unit: a preliminary study conducted in secret

Noise in hospitals frequently exceeds recommended levels and has detrimental psychological and physiological effects on patients and staff. The aim of this study was to record the noise levels within the cardiac surgical intensive care unit (CSICU) environment in secret. The device used was a CEL Instruments environmental noise meter concealed in a dummy box featuring temperature and humidity digital displays. It allowed greater than 16 hours recording time at a 1-minute resolution. The 24-hour period was covered by overlapping recordings. The data collected were downloaded onto a personal computer for analysis. The maximum sound level recorded was 100.9 decibel level (dBA), 1 min Lmax (the maximum sound level occurring in a 1-min period). The minimum sound level was 61.3 dBA 1 min Lmax. The continuous background noise was at its lowest at 57.5 dBA 1 min equivalent continuous sound pressure levels (Leq) and at its peak 77.3 dBA 1 min Leq. Noise in the CSICU was above the recommended levels for patients and staff well-being. Future studies will be designed to establish a correlation between sound levels and events.

Timeliness and quality of care for elderly patients with acute myocardial infarction under health maintenance organization vs fee-for-service insurance

BACKGROUND

A commonly voiced concern is that health maintenance organizations (HMOs) may withhold or delay the provision of urgent, essential care, especially for vulnerable patients like the elderly.

OBJECTIVE

To compare the quality of emergency care provided in Minnesota to elderly patients with acute myocardial infarction (AMI) who are covered by HMO vs fee-for-service (FFS) insurance.

METHODS

We reviewed the medical records of 2304 elderly Medicare patients who were admitted with AMI to 20 urban community hospitals in Minnesota (representing 91% of beds in areas served by HMOs) from October 1992 through July 1993 and from July 1995 through April 1996.

MAIN OUTCOME MEASURES

Use of emergency transportation and treatment delay (>6 hours from symptom onset); time to electrocardiogram; use of aspirin, thrombolytics, and beta-blockers among eligible patients; and time from hospital arrival to thrombolytic administration (door-to-needle time).

RESULTS

Demographic characteristics, severity of symptoms, and comorbidity characteristics were almost identical among HMO (n = 612) and FFS (n = 1692) patients. A cardiologist was involved as a consultant or the attending physician in the care of 80% of HMO patients and 82% of FFS patients (P = .12). The treatment delay, time to electrocardiogram, use of thrombolytic agents, and door-to-needle times were almost identical. However, 56% of HMO patients and 51% of FFS patients used emergency transportation (P = .02); most of this difference was observed for patients with AMIs that occurred at night (60% vs 52%; P = .02). Health maintenance organization patients were somewhat more likely than FFS patients to receive aspirin therapy (88% vs 83%; P = .03) and beta-blocker therapy (73% vs 62%; P = .04); these differences were partly explained by a significantly larger proportion of younger physicians in HMOs who were more likely to order these drug therapies. All differences were consistent across the 3 largest HMOs (1 staff-group model and 2 network model HMOs). Logistic regression analyses controlling for demographic and clinical variables produced similar results, except that the differences in the use of beta-blockers became insignificant.

CONCLUSIONS

No indicators of timeliness and quality of care for elderly patients with AMIs were lower under HMO vs FFS insurance coverage in Minnesota. However, two indicators of quality care were slightly but significantly higher in the HMO setting (use of emergency transportation and aspirin therapy). Further research is needed in other states, in different populations, and for different medical conditions.

Endothelial-cell-stimulating angiogenesis factor (ESAF) activates progelatinase A (72 kDa type IV collagenase), prostromelysin 1 and procollagenase and reactivates their complexes with tissue inhibitors of metalloproteinases: a role for ESAF in non-inflammatory angiogenesis

Endothelial-cell-stimulating angiogenesis factor (ESAF) has been shown to activate procollagenase and reactivate complexes of collagenase and gelatinase A with tissue inhibitor of metallo-proteinase (TIMP)-1. In the present paper we show a purification protocol for bovine pineal ESAF and that purified ESAF activates progelatinase A and prostromelysin-1. Unlike the activation of procollagenase by plasmin/plasminogen activator, which requires the presence of stromelysin for full activation, ESAF is able to activate fully all three proenzymes. Purified ESAF is also shown to reactivate the complexes of gelatinase A, collagenase and stromelysin-1 with TIMP-2. Once separated, both enzyme and inhibitor are active; however, ESAF binds to the enzyme in a manner preventing it from further inhibition by TIMP. ESAF is the only physiological molecule able to reactivate the TIMP/enzyme complex.

Production of endothelial cell stimulating angiogenesis factor (ESAF) by chondrocytes during in vitro cartilage calcification

The aim of this study was to identify the stimulus for production of the latent collagenase and angiogenic activator ESAF by growth plate chondrocytes. Stimulation correlated most closely with matrix calcification. Alkaline phosphatase was necessary for calcification (and so stimulation of ESAF production) but we could find no evidence for a direct link with ESAF production. ESAF production was also stimulated by addition of preformed mineral to non-calcified cultures but was inhibited by dexamethasone. Protein synthesis was necessary for the stimulation of ESAF production by calcification, though ESAF is not itself a protein. Based on these findings we suggest that chondrocytes, at a suitable stage of maturation in the growth plate, are stimulated to produce ESAF by the proximity of crystals in the matrix. Stimulation, which may consist of the induction of an enzyme or transport protein, leads to the release of this potent activator of collagenolysis as part of the angiogenic cascade.