Management of suicidal risk in the emergency department: A clinical pathway using the computerized adaptive screen for suicidal youth

Objective

Given the critical need for efficient and tailored suicide screening for youth presenting in the emergency department (ED), this study establishes validated screening score thresholds for the Computerized Adaptive Screen for Suicidal Youth (CASSY) and presents an example of a suicide risk classification pathway.

Methods

Participants were primarily from the Study One derivation cohort of the Emergency Department Screen for Teens at Risk for Suicide (ED-STARS) enrolled in collaboration with Pediatric Emergency Care Applied Research Networks (PECARN). CASSY scores corresponded to the predicted probabilities of a suicide attempt in the next 3 months and risk thresholds were classified as minimal (<1%), low (1%-5%), moderate (5%-10%), and high (>10%). CASSY scores were compared to risk thresholds derived from clinical consensus and ED complaints and dispositions. CASSY risk thresholds were also examined as predictors of future suicide attempts in the Study Two validation cohort of ED-STARS.

Results

A total of 1452 teens were enrolled with a median age of 15.2 years, 59.5% were female, 55.6% were White, 22% were Black, 22.3% were Latinx, and 42.8% received public assistance. The clinical consensus suicide risk groups were strongly associated with the CASSY-predicted risk thresholds. Suicide attempts in the Study Two cohort occurred at a frequency consistent with the CASSY-predicted thresholds.

Conclusions

The CASSY can be a valuable tool in providing patient-specific risk probabilities for a suicide attempt at 3 months and tailor the threshold cutoffs based on the availability of local mental health resources. We give an example of a clinical risk pathway, which should include segmentation of the ED population by medical versus psychiatric chief complaint.

The Cost of Universal Suicide Risk Screening for Adolescents in Emergency Departments

Suicide is the second leading cause of death among adolescents. As nearly 20% of adolescents visit emergency departments (EDs) each year, EDs have an opportunity to identify previously unrecognized suicide risk. A novel Computerized Adaptive Screen for Suicidal Youth (CASSY) was shown in a multisite study to be predictive for suicide attempts within 3 months. This study uses site-specific data to estimate the cost of CASSY implementation with adolescents in general EDs. When used universally with all adolescents who are present and able to participate in the screening, the average cost was USD 5.77 per adolescent. For adolescents presenting with non-behavioral complaints, the average cost was USD 2.60 per adolescent. Costs were driven primarily by time and personnel required for the further evaluation of suicide risk for those screening positive. Thus, universal screening using the CASSY, at very low costs relative to the cost of an ED visit, can facilitate services needed for at-risk adolescents.

Alcohol intake in relation to suicidal ideation and behavior among university students

ObjectiveHeavy alcohol use has been clearly linked to risk for suicidal behaviors and is also prevalent on many American college campuses. This report uses a large sample of college students to explore relationships between alcohol use, depressive symptoms, and suicidality. Methods: A brief suicide screen was completed by 40,335 university students at four pariticipating sites. Assessments quantified recent depressive symptoms, alcohol use, suicidal ideation, and suicide attempts. Results: Problems from alcohol use were consistently associated with suicidal thoughts and attempts in the previous month, and in the previous year, but the quantity of alcohol used was not. Alcohol related problems exerted effects on the likelihood of both suicide ideation and attempts beyond those explained by their relationship with depressive symptoms. Conclusions: Screens for individuals at increased risk for suicidal ideation and behavior should emphasize alcohol-related problems over quantification of alcohol intake.

Suicidality and Alcohol Use as Predictors of Future Suicidal Behavior in College Students

AIMS

There has been a marked increase in suicide fatalities among college-age students in recent years. Moreover, heavy alcohol use, a well-known risk factor for suicide, is present on most campuses. Yet, no prospective studies have examined alcohol use patterns among college students as predictors of suicidal behaviors.

METHODS

Online of 40,335 students at four universities took place at the beginning of four academic years, 2015-2018. Of these, 2296 met criteria for an increased risk of suicidal behavior and completed 1- and/or 6-month follow-up evaluation(s). Baseline assessments included the Alcohol Use Disorders Identification Test to quantify alcohol consumption and resulting problems, and measures of depression, suicidal ideation and suicidal behavior.

RESULTS

Suicide attempts during follow-up were reported by 35 (1.5%) of high-risk students. Regression analyses indicated that baseline severity of alcohol use consequences, but not amount of alcohol consumption, was associated with greater odds of a follow-up suicide attempt after controlling for baseline suicidal ideation, functional impairment and history of suicide attempts.

CONCLUSIONS

Among college students at elevated risk for suicide, the severity of alcohol-related consequences was a significant predictor of future suicide attempts. Alcohol consumption was not a significant predictor, suggesting that the amount students drink is less of a concern for suicidal behavior than are the problems (e.g. failing to meet expectations, experiencing blackouts) associated with drinking.

Utilizing daily mood diaries and wearable sensor data to predict depression and suicidal ideation among medical interns

BACKGROUND

Intensive longitudinal methods (ILMs) for collecting self-report (e.g., daily diaries, ecological momentary assessment) and passive data from smartphones and wearable sensors provide promising avenues for improved prediction of depression and suicidal ideation (SI). However, few studies have utilized ILMs to predict outcomes for at-risk, non-clinical populations in real-world settings.

METHODS

Medical interns (N = 2881; 57 % female; 58 % White) were recruited from over 300 US residency programs. Interns completed a pre-internship assessment of depression, were given Fitbit wearable devices, and provided daily mood ratings (scale: 1-10) via mobile application during the study period. Three-step hierarchical logistic regressions were used to predict depression and SI at the end of the first quarter utilizing pre-internship predictors in step 1, Fitbit sleep/step features in step 2, and daily diary mood features in step 3.

RESULTS

Passively collected Fitbit features related to sleep and steps had negligible predictive validity for depression, and no incremental predictive validity for SI. However, mean-level and variability in mood scores derived from daily diaries were significant independent predictors of depression and SI, and significantly improved model accuracy.

LIMITATIONS

Work schedules for interns may result in sleep and activity patterns that differ from typical associations with depression or SI. The SI measure did not capture intent or severity.

CONCLUSIONS

Mobile self-reporting of daily mood improved the prediction of depression and SI during a meaningful at-risk period under naturalistic conditions. Additional research is needed to guide the development of adaptive interventions among vulnerable populations.

Morning light treatment for traumatic stress: The role of amygdala reactivity study protocol

Background

Exposure to trauma can result in various mental health disorders including anxiety, depression, and posttraumatic stress disorder (PTSD). Although psychotherapies and pharmacotherapies exist for the treatment of these disorders, many individuals fail to receive treatment and among those who do, many remain symptomatic. Therefore, it is critical to continue developing new interventions for traumatic stress that target underlying mechanisms of pathology and offer a safe and acceptable alternative to current treatments. Morning light treatment has good potential as a novel non-invasive, low risk treatment for traumatic stress. Evidence suggests that morning light may improve traumatic stress by reducing reactivity in the amygdala, a brain region implicated in the pathophysiology of PTSD and anatomically linked to circadian photoreceptors in the eye.

Methods

In this study, we aim to establish a significant dose-response relationship between duration of morning light treatment and reduction in amygdala reactivity among individuals with traumatic stress symptoms (NCT# 04117347). Using a transdiagnostic approach, sixty-six individuals with a history of a DSM-5 criterion A trauma and traumatic stress symptoms will be recruited to participate in a 5-week study. Participants will be randomized across three treatment arms based on morning light treatment duration: 15-minutes, 30-minutes, or 60-minutes of light treatment per day for four weeks. To evaluate amygdala activity, participants will undergo fMRI at pre-treatment, mid-treatment, and post-treatment. Participants will also complete clinical assessments and self-report measures of PTSD, depression, and anxiety at pre-treatment, mid-treatment, and post-treatment.

Discussion

Morning light therapy may be an acceptable, feasible, and effective treatment for individuals suffering from traumatic stress. Identifying mechanistically relevant targets, and the doses needed to impact them, are critical steps in developing this new treatment approach for the sequelae of traumatic stress.

Electronic bridge to mental health for college students: A randomized controlled intervention trial

OBJECTIVE

Suicide is the second leading cause of death among college students in the United States, and the percentage of students reporting suicidal thoughts is increasing. Nevertheless, many students at risk do not seek mental health (MH) services. This randomized controlled trial (RCT) examined the efficacy of Electronic Bridge to Mental Health for College Students (eBridge) for increasing at-risk students' linkage to MH services.

METHOD

Students from four universities were recruited via email; 40,347 (22.6%) completed the online suicide risk screen; and 3,363 (8.3%) met criteria for randomization based on suicide risk factors and lack of current treatment (62.2% female, 35.0% male, 2.8% transgender/nonbinary; 73.2% White, 7.0% Black, 19.9% Asian, 11.7% other; 12.4% Hispanic, 76.2% undergraduate). These students were randomized to eBridge [personalized feedback (PF) with option of online counseling] or Control (PF). The primary outcome was linkage to MH services within 6 months.

RESULTS

Among students assigned to eBridge, 355 students (21.0%) posted ≥1 message, and 168 (10.0%) posted ≥2 messages to the counselor. In intent-to-treat analyses, there was no eBridge effect on obtaining MH services. However, within the eBridge group, students who posted ≥1 message were significantly more likely to link to MH services.

CONCLUSIONS

eBridge shows promise for reaching a relatively small subset of college students at risk for suicide; however, engagement in eBridge was low. This study underscores the urgent need for more effective strategies to engage young adults in online mental health interventions. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Analysis of Depressive Symptoms and Perceived Impairment Among Physicians Across Intern Year

This cohort study compares perceived impairment associated with depressive symptoms among physicians before intern year vs during intern year.

Connectedness to family, school, peers, and community in socially vulnerable adolescents

Youth who feel connected to people and institutions in their communities may be buffered from other risk factors in their lives. As a result, increasing connectedness has been recommended as a prevention strategy. In this study, we examined connectedness among 224 youth (ages 12-15), recruited from an urban medical emergency department, who were at elevated risk due to bullying perpetration or victimization, or low social connectedness. Regression analyses examined multiple domains of connectedness (family, school, peer, community) in relation to adjustment. Youth who felt more connected to parents reported lower levels of depressive symptoms, suicidal ideation, non-suicidal self-injury, and conduct problems, higher self-esteem and more adaptive use of free time. Youth who felt more connected to their school reported lower levels of depressive symptoms, suicidal ideation, social anxiety, and sexual activity, as well as higher levels of self-esteem and more adaptive use of free time. Community connectedness was associated with less social anxiety but more sexual activity, and peer connectedness was not related to youth adjustment in this unique sample. Findings suggest that family and school connectedness may buffer youth on a trajectory of risk, and may therefore be important potential targets for early intervention services.

Online suicide risk screening and intervention with college students: a pilot randomized controlled trial

OBJECTIVE

This pilot randomized controlled trial examined the effect of an online intervention for college students at risk for suicide, Electronic Bridge to Mental Health Services (eBridge), which included personalized feedback and optional online counseling delivered in accordance with motivational interviewing principles. Primary outcomes were readiness to seek information or talk with family and friends about mental health treatment, readiness to seek mental health treatment, and actual treatment linkage.

METHOD

Participants were 76 college students (45 women, 31 men; mean age = 22.9 years, SD = 5.0 years) at a large public university who screened positive for suicide risk, defined by at least 2 of the following: suicidal thoughts, history of suicide attempt, depression, and alcohol abuse. Racial/ethnic self-identifications were primarily Caucasian (n = 54) and Asian (n = 21). Students were randomized to eBridge or the control condition (personalized feedback only, offered in plain report format). Outcomes were measured at 2-month follow-up.

RESULTS

Despite relatively modest engagement in online counseling (29% of students posted ≥1 message), students assigned to eBridge reported significantly higher readiness for help-seeking scores, especially readiness to talk to family, talk to friends, and see a mental health professional. Students assigned to eBridge also reported lower stigma levels and were more likely to link to mental health treatment.

CONCLUSIONS

Findings suggest that offering students personalized feedback and the option of online counseling, using motivational interviewing principles, has a positive impact on students' readiness to consider and engage in mental health treatment. Further research is warranted to determine the robustness of this effect, the mechanism by which improved readiness and treatment linkage occurs, and the longer term impact on student mental health outcomes.

Acutely suicidal adolescents who engage in bullying behavior: 1-year trajectories

PURPOSE

Prospective longitudinal research is needed to examine associations between bullying behaviors and trajectories of suicidal ideation and behavior and overall functional impairment. The specific aims of the present study are to: (1) characterize differences in baseline functioning between acutely suicidal adolescents who are classified into bullying perpetrator and non-bully groups and (2) examine the 1-year trajectories of these two groups of adolescents.

METHOD

Participants were 433 psychiatrically hospitalized suicidal adolescents (72% female), ages 13 to 17 years. Participants reported suicidal ideation, depression, anxiety, substance use, adaptive functioning, and bullying behavior. Six items from the Youth Self-Report were used to classify adolescents into bullying perpetrator (n = 54) and non-bully (n = 379) groups. Follow-up assessments were conducted at 6 weeks, 3 months, 6 months, and 12 months.

RESULTS

At hospitalization, adolescents in the bully group reported significantly higher levels of suicidal ideation, substance use, and functional impairment. Suicidal ideation differences remitted at six weeks. The elevated functional impairment of the bullying perpetrator group persisted across the 12-month period.

CONCLUSION

Adolescents who met bullying perpetrator group criteria were characterized by more severe suicidal ideation and higher levels of proximal risk factors for suicide. Bullying behavior was not stable over time but was associated with elevated suicide risk when present. These findings highlight the importance of specifically assessing for and targeting bullying behavior at multiple time points when treating suicidal adolescents.

Cross-sensitization of histamine-independent itch in mouse primary sensory neurons

Overexpression of pruritogens and their precursors may contribute to the sensitization of histamine-dependent and -independent itch-signaling pathways in chronic itch. We presently investigated self- and cross-sensitization of scratching behavior elicited by various pruritogens, and their effects on primary sensory neurons. The MrgprC11 agonist BAM8-22 exhibited self- and reciprocal cross-sensitization of scratching evoked by the protease-activated receptor-2 (PAR-2) agonist SLIGRL. The MrgprA3 agonist chloroquine unidirectionally cross-sensitized BAM8-22-evoked scratching. Histamine unidirectionally cross-sensitized scratching evoked by chloroquine and BAM8-22. SLIGRL unidirectionally cross-sensitized scratching evoked by chloroquine. Dorsal root ganglion (DRG) cells responded to various combinations of pruritogens and algogens. Neither chloroquine, BAM8-22 nor histamine had any effect on responses of DRG cell responses to subsequently applied pruritogens, implying that their behavioral self- and cross-sensitization effects are mediated indirectly. SLIGRL unilaterally cross-sensitized responses of DRG cells to chloroquine and BAM8-22, consistent with the behavioral data. These results indicate that unidirectional cross-sensitization of histamine-independent itch-signaling pathways might occur at a peripheral site through PAR-2. PAR-2 expressed in pruriceptive nerve endings is a potential target to reduce sensitization associated with chronic itch.

Stably transfected ABCA1 antisense cell line has decreased ABCA1 mRNA and cAMP-induced cholesterol efflux to apolipoprotein AI and HDL

Using a sensitive real time fluorescent PCR assay, ABCA1 mRNA levels were induced by approximately 50-70-fold following 8Br-cAMP treatment of the RAW264 murine macrophage cell line, concomitant with the induction of cholesterol efflux to apoAI and HDL. A stably transfected ABCA1 antisense cDNA cell line was created, which led to approximately 50-70% reductions in ABCA1 mRNA levels in basal and 8Br-cAMP-treated cells, and diminished to the same extent the 8Br-cAMP-mediated efflux of cholesterol to apolipoprotein AI and HDL. These data demonstrate that ABCA1 is necessary for the cAMP-induced lipid efflux to both apoAI and HDL.

Identification of cAMP analogue inducible genes in RAW264 macrophages

RNA was isolated from RAW264 cells treated with or without 8-Br-cAMP and the differential display and subtractive hybridization methods were performed. One hundred and twenty-five differentially displayed bands were identified. Upon Northern blot analysis, only three of these bands were confirmed as cAMP inducible mRNAs, named cI-1, cI-2, and cI-3 (for cAMP inducible genes 1-3). The cI-3 probe was identical to a previously known gene, gly96. Using the novel cI-1 and cI-2 partial cDNAs as probes, a mouse macrophage cDNA library was screened and the two full length genes were cloned, sequenced, and characterized as encoding large hydrophobic proteins. One hundred and fifteen partial cDNA clones from a subtractive hybridization library were also screened by Northern blot and 64 were found to be cAMP inducible. Of these, 45 represented 31 known unique genes in the GenBank nr database (cI-4-34), and 19 clones representing 15 unique sequences were not in the nr database (cI-35-49). One of the previously known genes was ABC1, the Tangier disease gene, which was identified from four independent partial cDNAs. ABC1 was upregulated in RAW cells by cAMP, concurrent with the cAMP induction of lipid efflux to apolipoprotein A1.

Cellular localization of complement C3 and C4 transcripts in intestinal specimens from patients with Crohn's disease

It has been suggested that the increase in C3 and C4 levels in jejunal perfusates of patients with Crohn's disease (CD) results from local intestinal synthesis of complement. The present study evaluated the expression of these complement genes in inflamed tissues from patients with CD. Surgically resected specimens from patients with CD and control tissue obtained from subjects with adenocarcinoma of the colon were evaluated for C3 and C4 gene expression by the use of 35S-labelled anti-sense RNA probes. All tissue samples, diseased and normal tissue, expressed C4 mRNA throughout in the intestinal epithelium. C3 mRNA was not detected in epithelial cells in histologically normal tissue, but in diseased specimens there was a focal distribution of C3 mRNA in epithelial cells of the crypts, but not in villous epithelium. Focal C3 gene expression correlated with crypt abscess formation and the presence of polymorphonuclear leucocytes in the lumen of the crypts. In addition, C3 mRNA was also found in macrophages of the submucosa. These macrophages were CD68+, fusiform with faint cytoplasm and morphologically different from the large rounded lamina propria macrophages, which do not express C3 mRNA. Multinucleated giant cells did not express either C3 or C4 genes. In addition to its presence in intestinal epithelium, C4 mRNA was also expressed in mast cells, which however did not express C3 mRNA. These observations identify cells in the intestinal wall expressing complement genes and support the hypothesis that there is local regulated production of complement in the intestine of patients with CD, and subsequent complement activation may contribute to the inflammatory process.

[Reflections on an anniversary: the Public Health School of Chile in its fiftieth anniversary]

This is the speech pronounced by Dr Abraham Horwitz, Emeritus Professor of the University of Chile and Honorary Director of PAHO, during the academic act that celebrated the fiftieth anniversary of the Chilean Public Health School endowment. The school had a doctrinal and technical impact on Chilean health and decisively influenced the National Health Service creation. The majority of its founders were trained at the John Hopkins Public Health School, therefore naming this school "little Hopkins". Its creation was stimulated by the Chilean health profile of the forties. Chile had 5,273,000 inhabitants and a 28.2% of illiteracy. General mortality was 19.5%, infant mortality 18.1 and newborn mortality 73.3%. At the present time, forty years later, the figures are 14,000,000 inhabitants (85% in urban areas), less than 10% of illiteracy, a general mortality of 5.6%, infant mortality of 14.6, newborn mortality of 7.9% and a life expectancy of 72 and 75 years for men and women. Almost all labors are attended by professionals in institutional settings and only 5.6% of newborns have a low birth weight, one of the lowest figures in the world. To say that health in the Americas is in crisis and that population health needs are not satisfied is a dangerous generalization and Chilean health evolution seems to disprove this assertion. This does not mean that some reforms are needed that can be accomplished with the help of School of Public Health.

Monocyte tissue factor induction by lipopolysaccharide (LPS): dependence on LPS-binding protein and CD14, and inhibition by a recombinant fragment of bactericidal/permeability-increasing protein

Mononuclear phagocytes, stimulated by bacterial lipopolysaccharide (LPS), have been implicated in the activation of coagulation in sepsis and endotoxemia. In monocytes LPS induces the synthesis of tissue factor (TF) which, assembled with factor VII, initiates the blood coagulation cascades. In this study we investigated the mechanism of LPS recognition by monocytes, and the consequent expression of TF mRNA and TF activity. We also studied the inhibition of these effects of LPS by rBPI23, a 23-kD recombinant fragment of bactericidal/permeability increasing protein, which has been shown to antagonize LPS in vitro and in vivo. Human peripheral blood mononuclear cells, or monocytes isolated by adherence, were stimulated with Escherichia coli O113 LPS at physiologically relevant concentrations (> or = 10 pg/mL). The effect of LPS was dependent on the presence of the serum protein LBP (lipopolysaccharide-binding protein), as shown by the potentiating effect of human recombinant LBP or serum. Furthermore, recognition of low amounts of LPS by monocytes was also dependent on CD14 receptors, because monoclonal antibodies against CD14 greatly reduced the LPS sensitivity of monocytes in the presence of serum or rLBP. Induction of TF activity and mRNA expression by LPS were inhibited by rBPI23. The expression of tumor necrosis factor showed qualitatively similar changes. Considering the involvement of LPS-induced TF in the potentially lethal intravascular coagulation in sepsis, inhibition of TF induction by rBPI23 may be of therapeutic benefit.

Intermittent encephalopathy, reversible nerve conduction slowing, and MRI evidence of cerebral white matter disease in methylenetetrahydrofolate reductase deficiency

We describe a patient with methylenetetrahydrofolate reductase (MTHFR) deficiency in whom clinical and electrophysiologic fluctuations paralleled exacerbations of hyperhomocyst(e)inemia. MRI demonstrated abnormalities characteristic of a leukodystrophy.

A recombinant amino terminal fragment of bactericidal/permeability-increasing protein inhibits the induction of leukocyte responses by LPS

Bactericidal/permeability-increasing protein (BPI) is a major component of the granules of polymorphonuclear neutrophils (PMNs) and is involved in the killing of gram-negative bacteria. A 23-kd recombinant protein, corresponding to the NH2-terminal fragment of human BPI (rBPI23), has been shown to bind lipid A and antagonize some lipopolysaccharide (LPS)-mediated effects. In this study the ability of rBPI23 to prevent a wide range of cellular responses to LPS was investigated. In vitro assays were carried out using human blood to more closely approximate in vivo conditions. The release of proinflammatory cytokines [tumor necrosis factor (TNF), interleukin-1 beta (IL-1 beta), IL-6, IL-8], induced by E. coli O113 LPS, was markedly reduced by rBPI23 in a concentration-dependent fashion. The production of the anti-inflammatory protein IL-1ra (IL-1 receptor antagonist) was triggered by lower LPS concentrations than those necessary for the other cytokines. Furthermore, prevention of IL-1ra release required higher rBPI23 concentrations than for other cytokines. The LPS-induced production of oxygen-derived free radicals by phagocytic cells (resulting in chemiluminescence) was also prevented by rBPI23. The inhibition was specific for LPS because the activation of leukocytes by phorbol myristate acetate, zymosan, or TNF was unaffected by BPI. The ability of rBPI23 to antagonize specifically the effects of endotoxin in the complex environment of human blood along with its bactericidal activity suggests that rBPI23 may be a novel therapeutic agent in the treatment of gram-negative infections.

Protective effect of a recombinant amino-terminal fragment of bactericidal/permeability-increasing protein in experimental endotoxemia

Bactericidal/permeability-increasing protein (BPI), a cationic protein found in neutrophil granules, binds with high affinity to gram-negative bacterial lipopolysaccharide (LPS) and can inhibit its actions in vitro. The in vivo efficacy of a recombinant 23-kDa amino-terminal LPS-binding fragment of BPI (rBPI23) was assessed in a mouse model of lethal endotoxemia. Systemic administration of rBPI23 protected actinomycin D-sensitized mice from lethal LPS (Escherichia coli O111:B4) challenge in a dose-dependent manner, with almost complete protection at the highest dose (10 mg/kg; 93% survival vs. 13% in vehicle-treated controls). Surviving rBPI23-treated animals did not show histopathologic signs of tissue damage evident in control animals that had died after LPS challenge. rBPI23 also attenuated the LPS-induced elevation in serum levels of tumor necrosis factor-alpha and interleukin-1 alpha, mediators believed to be involved in the pathogenesis of endotoxemia and sepsis. Thus, rBPI23 may be a potential new therapeutic agent for the treatment of gram-negative bacterial infection and sepsis.

High-affinity binding of the bactericidal/permeability-increasing protein and a recombinant amino-terminal fragment to the lipid A region of lipopolysaccharide

Bactericidal/permeability-increasing protein (BPI) is a 55-kDa cationic protein (nBPI55) elaborated by polymorphonuclear neutrophils (PMN). BPI has potent bactericidal activity against a wide variety of gram-negative organisms and neutralizes endotoxin activities. An N-terminal fragment of nBPI55 exhibits the bactericidal and antiendotoxin properties of the holoprotein. To further characterize the biological activities of the N-terminal fragment, a recombinant protein (rBPI23) corresponding to the first 199 amino acids of human BPI was produced and purified. rBPI23 had antibacterial activity equivalent to that of nBPI55 against Escherichia coli J5. Furthermore, both rBPI23 and nBPI55 bound identically to a broad range of R- and S-form lipopolysaccharides (LPS) and to natural and synthetic lipid A. Binding of radiolabeled nBPI55 to LPS was inhibited in an identical fashion by either nBPI55 or rBPI23. The binding of both proteins to immobilized E. coli J5 lipid A was inhibited in a comparable fashion by long- or short-chain LPS or lipid A. The binding of both rBPI23 and nBPI55 was specific, saturable, and of high affinity, with an apparent Kd of approximately 2 to 5 nM for all ligands tested. These results demonstrate that BPI recognizes the highly conserved lipid A region of bacterial LPS via residues contained within the amino-terminal portion of the BPI molecule.

Human bactericidal/permeability-increasing protein and a recombinant NH2-terminal fragment cause killing of serum-resistant gram-negative bacteria in whole blood and inhibit tumor necrosis factor release induced by the bacteria

The bactericidal/permeability-increasing protein (BPI) of neutrophils and BPI fragments neutralize the effects of isolated Gram-negative bacterial lipopolysaccharides both in vitro and in vivo. Since endotoxin most commonly enters the host as constituents of invading Gram-negative bacteria, we raised the question: Can BPI and its bioactive fragments also protect against whole bacteria? To determine whether the bactericidal and endotoxin-neutralizing activities of BPI/fragments are expressed when Gram-negative bacteria are introduced to the complex environment of whole blood we examined the effects of added BPI and proteolytically prepared and recombinant NH2-terminal fragments on: (a) the fate of serum-resistant encapsulated Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa that survive the antibacterial actions of whole blood and (b) the ability of these bacteria to trigger cytokine release. Added BPI in nanomolar concentrations killed each of three encapsulated strains of E. coli and in closely parallel fashion inhibited tumor necrosis factor (TNF) release. Holo-BPI and its NH2-terminal fragment were equipotent toward a rough LPS chemotype K1-encapsulated strain, but the fragment was substantially more potent than holo-BPI toward two encapsulated smooth LPS chemotype strains. TNF release induced by K. pneumoniae and P. aeruginosa was also inhibited by both holo-BPI and fragment but, at the protein concentrations tested, P. aeruginosa was killed only by the fragment and K. pneumoniae was not killed by either protein. The bactericidal action of BPI/fragment toward E. coli is inhibited by C7-depleted serum, but accelerated by normal serum, indicating that BPI, acting in synergy with late complement components, enhances extracellular killing of serum-resistant bacteria. Thus, BPI and an even more potent NH2-terminal fragment may protect against Gram-negative bacteria in the host by blocking bacterial proliferation as well as endotoxin-mediated effects, not only as components of the intracellular antibacterial arsenal of the neutrophil, but also as potentially therapeutic extracellular agents.

[The Chilean National Health Service: an intellectual and humanitarian adventure]

This is the speech delivered by Dr Abraham Horwitz, Emeritus Director of the Panamerican Health Organization, when he was granted a decoration from the Chilean Government. I believe--he said--that protection and promotion of health are not only an ethical imperative but also a basic political need of nations and peoples, a foundation for peace and development of human beings and society. Analyzing the origin and development of the Chilean National Health Service in 1952, he concludes that this was an intellectual and humanitarian endeavour of a group of idealists who devoted their best to improve the condition of the Chilean people.

[From cell to society: in search of just social welfare]

This is a speech delivered by Dr Abraham Horwitz upon receiving the Professor Honoris Causa degree from the University of Chile. Dr Horwitz was the Director of the Panamerican Health Organization for 4 consecutive periods (1958-1975). Preventive Medicine and Health Promotion are effective means to increase social wellbeing. They should be implemented at all levels of health care. By increasing the span of healthy and productive life, the health industry makes a direct contribution to development and the economy. Government investment in health reflects the value attributed by society to social wellbeing. Research and better administration of health resources will allow to reduce costs and increase productivity of health and nutritional programs.

Intermediate hyperhomocysteinemia resulting from compound heterozygosity of methylenetetrahydrofolate reductase mutations

Four subjects with thermolabile methylenetetrahydrofolate reductase (MTHFR) were discovered among 16 "obligate" heterozygotes for severe MTHFR deficiency and their family members. All four subjects had less than 25% of normal mean MTHFR specific activity in lymphocyte extracts. Three of them with normal serum folate and cyanocobalamin had intermediate hyperhomocysteinemia, and one with high serum folate and cyanocobalamin had no excessive accumulation of serum homocysteine. The biochemical features in these four subjects are distinguishable from subjects homozygous for the thermolabile MTHFR, whose specific activity is approximately 50% of the normal mean, and from heterozygotes for severe MTHFR deficiency, in whom the enzyme is thermostable and has a specific activity of about 50% of the normal mean. We propose that these four subjects are genetic compounds of the allele for the severe mutation and the allele for thermolabile mutation of the MTHFR gene. It is postulated that subjects with this genetic compound are more susceptible to the development of intermediate hyperhomocysteinemia despite normal folate and B12 levels. Nonetheless, hyperhomocysteinemia due to this compound heterozygosity is correctable by oral folic acid therapy.

Expression and function of chicken integrin beta 1 subunit and its cytoplasmic domain mutants in mouse NIH 3T3 cells

Chicken integrin beta 1 cDNA and its site-directed mutants were cloned into a mammalian expression vector and introduced into mouse NIH 3T3 cells. Stable transfectants expressing the chicken beta 1 subunit or its site-directed mutants were identified by immunostaining with antibodies specific for the chicken integrin beta 1 subunit. The chicken beta 1 proteins were expressed predominately in the endoplasmic reticulum of transfectants and to a lesser degree in the plasma membrane. Immunoblots and immunoprecipitations, using anti-chicken integrin antibodies, revealed three different sizes of the chicken subunit (90, 95, and 120 kD) and a mouse 140-kD alpha subunit. Immunoprecipitations of the cell surface receptors showed only two peptides, an 120-kD beta 1 and an 140-kD alpha subunit. Antibodies perturbing mouse and chicken integrin-specific cell adhesions were used to demonstrate that the chimeric receptors functioned in adhesion to both laminin and fibronectin. Immunofluorescent staining with antibodies specific for either the chicken or mouse receptors showed that both the wild type and the chimeric receptors localized in focal contacts. Several mutations in the cytoplasmic domain were synthesized and used in the transfection experiments. In one mutant the tyrosine (Tyr 788) in the consensus sequence for phosphorylation was replaced by a phenylalanine. In another the lysine (Lys 757) at the end of the membrane spanning region was replaced by a leucine. Both of these mutants formed dimers with mouse alpha subunits, participated in adhesion, localized in focal contacts, and displayed biological properties indistinguishable from the wild-type transfection. In contrast, mutants containing deletions greater than 5-15 amino acids nearest the carboxyl end in the cytoplasmic domain neither promoted adhesion nor localized in focal contacts. They did, however, form heterodimers that were expressed on the cell surface.

Integrins isolated from Rous sarcoma virus-transformed chicken embryo fibroblasts

Avian integrins are a complex of three integral membrane glycoproteins that are thought to have a role both in anchoring the cytoskeleton to the plasma membrane and establishing linkages to the extracellular matrix. We previously demonstrated that bands 2 and 3 of integrin are phosphorylated on both tyrosine and serine residues in chicken embryo fibroblasts (CEF) transformed with Rous Sarcoma virus (RSV) and other oncogenic retroviruses. The effects of RSV transformation on integrins from chick cells are now further characterized. The major site of tyrosine phosphorylation on band 3 in RSV transformed CEF has been identified as tyrosine 788. We also demonstrate that the product of the RSV oncogene, pp60v-src, can phosphorylate integrin in vitro, at the same residue. Tryptic peptide mapping and tunicamycin treatment indicates that a previously observed 4-8 k increase in the Mr of integrins from RSV-transformed cells can be attributed to an alteration in a post-translational modification such as glycosylation. Equilibrium gel filtration assays were used to test the ability of integrins from RSV-transformed CEF to interact with talin and fibronectin. Tyrosine phosphorylated integrins showed a decreased ability to interact with both these ligands in vitro. Conversely, integrins isolated from RSV-transformed CEF metabolically labeled in the absence of phosphatase inhibitor contained only low levels of phosphotyrosine and showed an almost normal ability to interact with ligands. Competition experiments indicated that the region of integrin containing tyrosine 788 is also important for talin binding to integrins.

[Food guidelines and nutritional goals for aging]

As a contribution to the formulation of food guidelines and nutritional goals for Latin America, this article examines the singular situation of the elderly, defined as those persons over 60 years of age. The projected data for the year 2025, published by the Population Department of the United Nations, show that this age group represents an important sector--6.4% of the population in 1980--that is growing. Some countries, however, do have a rate that is comparable to the United States, 11.3%, such as Argentina, 12.7%, and Uruguay, 14.8%, which is similar to that of Europe. Along with other comparative demographic information, the analysis covers some of the biological, physiological, pathological, and psychosocial characteristics that become more common in senescence. To a certain extent, these characteristics bear a direct or indirect relationship with the energy, protein, and nutrient content of the diet. This becomes more evident upon examining the causes of mortality and morbidity in the elderly, whose diseases are quite often chronic and degenerative. Those with the highest incidence, such as the cardiovascular ones--including cerebrovascular accidents, atherosclerosis, and hypertension--diabetes, obesity, osteoporosis, anemias from lack of iron and folates, and some forms of cancer, reveal the influence of certain nutrients in their pathogenesis. Very few studies have been done on the over-70 age group to determine their requirements for energy, proteins, and various nutrients that serve as the basis for appropriate food guidelines. Usually, estimates are extrapolated from data on the 40-and-over age group. Some maintain that the variations for the elderly are small, but since this group is growing and is far from homogeneous, such a hypothesis must be tested. Following a review of recent literature, the article proposes a set of Food Guidelines and Nutritional Goals for persons over 60 in Latin America. It also recommends to countries interested in formulating their own guidelines how to proceed for the short, medium, and long terms. In Latin America and the Caribbean, the elderly are the most neglected group with reference to government programs, and most forgotten by society. They depend to a great extent on the labor force of each country. They suffer most frequently from chronic diseases and have the most need for medical care, they use a broad range of drugs that may interfere with the absorption and utilization of nutrients, as well as foods when may impair the bioavailability of drugs. They show the highest mortality rates, and, in a high proportion, require a normal diet.(ABSTRACT TRUNCATED AT 400 WORDS)

Combinations of monoclonal antibodies distinguish mesenchymal, myogenic, and chondrogenic precursors of the developing chick embryo

Monoclonal antibodies (MAbs) were used as probes for molecular differences in the surfaces of nonterminally differentiated cells of the developing chick limb. The specificity of the MAbs was determined by immunofluorescent localization performed on cultured breast muscle and limb bud cells and cryosections of a variety of embryonic (stages 15-37) and neonatal tissues. Subpopulations of MAb-positive and -negative cells were isolated by fluorescence-activated cell sorting and their developmental potential was assessed in vitro. Cells of the compacted somite, lateral plate mesoderm, and early limb bud were labeled with the CSAT MAb. Myogenic precursors of the dermatome and limb bud were labeled with the CSAT and L4 MAbs. Chondrogenic precursors of the sclerotome and limb bud were labeled with the CSAT, L4, and C5 MAbs. These precursors were distinguished from fibroblasts which were labeled with the CSAT and C1 MAbs. The differentiation and maturation of muscle and cartilage were accompanied by alterations in the labeling patterns of the MAbs. These results indicate that combinations of these MAbs can be used to distinguish mesenchymal, myogenic, and chondrogenic precursors, identify their site of origin during development, and isolate subpopulations of embryonic cells.

Phosphorylation of the fibronectin receptor complex in cells transformed by oncogenes that encode tyrosine kinases

The fibronectin (FN) receptor in avian cells has been characterized previously as a complex of three membrane glycoproteins of about Mr 160,000, Mr 140,000, and Mr 120,000 (simply termed protein band 1, band 2, and band 3, respectively). Monoclonal antibodies to the band 3 protein of the complex prevent FN and laminin binding both in vivo and in vitro and enable the detection of the receptor proteins in the plasma membrane and in adhesion plaques. Association of the FN receptor proteins with the adhesion-plaque protein talin also has been reported. We now find that the band 2 and band 3 proteins in the complex are phosphorylated in Rous sarcoma virus-transformed chicken cells but not in normal chicken cells. Phosphorylation occurs predominantly on tyrosine and is accompanied by a reorganization of the receptor complex in the membrane of the transformed cells. Whereas normal cells contain the FN receptor in focal contacts and cellular processes between cells, v-src-transformed cells exhibit a more diffuse distribution of this receptor. In addition to the viral v-src oncogene, cells transformed by other avian oncogenes that also encode tyrosine kinases (v-fps, v-erbB, and v-yes) also express the receptor complex proteins in the phosphorylated state regardless of whether the transforming protein is detectable in adhesion plaques. These results suggest that the altered FN and laminin receptor proteins may contribute to the transformed phenotype, but their significance and role in the transformed state remain to be established.

Interaction of plasma membrane fibronectin receptor with talin--a transmembrane linkage

Many observations suggest the presence of transmembrane linkages between the cytoskeleton and the extracellular matrix. In fibroblasts both light and electron microscopic observations reveal a co-alignment between actin filaments at the cell surface and extracellular fibronectin. These associations are seen at sites of cell matrix interaction, frequently along stress fibres and sometimes where these bundles of microfilaments terminate at adhesion plaques (focal contacts). Non-morphological evidence also indicates a functional linkage between the cytoskeleton and extracellular matrix. Addition of fibronectin to transformed cells induces flattening of the cells and a reorganization of the actin cytoskeleton, with the concomitant appearance of arrays of stress fibres. Conversely, disruption of the actin cytoskeleton by treatment with cytochalasin B leads to release of fibronectin from the cell surface. As yet, there is no detailed knowledge of the molecules involved in this transmembrane linkage, although several proteins have been suggested as candidates in the chain of attachment between bundles of actin filaments and the cytoplasmic face of the plasma membrane: these include vinculin, alpha-actinin and talin, each one having been identified at regions where bundles of actin filaments interact with the plasma membrane and underlying cell-surface fibronectin. Recently, the cell-substrate attachment (CSAT) antigen has been identified as a plasma membrane receptor for fibronectin, raising the possibility that this glycoprotein complex may serve as a bridge between fibronectin and one or more of the underlying cytoskeletal components mentioned. Here we have investigated the interaction of the purified CSAT antigen with these cytoskeletal components, and we demonstrate an interaction specifically between the CSAT antigen and talin.

An application of three deviance theories to adolescent substance use

This study tests the applicability of aspects of three theories of deviance--differential association, control, and strain--to the use of alcohol and drugs among a representative cross-section of 12-, 15-, and 18-year-olds. Regression analyses are conducted separately on each theory as well as on an overall model combining aspects of all three perspectives. Results show that differential association theory is a far more powerful predictor of adolescent alcohol and drug use than either the control or strain theories. The predictive power of the overall model is dependent upon the type of substance used as well as the age of the subject; however, the model is invariant between males and females.

The cell substrate attachment (CSAT) antigen has properties of a receptor for laminin and fibronectin

The cell substrate attachment (CSAT) antigen is an integral membrane glycoprotein complex that participates in the adhesion of cells to extracellular molecules. The CSAT monoclonal antibody, directed against this complex, inhibited adhesion of cardiac and tendon fibroblasts and skeletal myoblasts to both laminin and fibronectin, thus implicating the CSAT antigen in adhesion to these extracellular molecules. Equilibrium gel filtration was used to explore the hypothesis that the CSAT antigen functions as a cell surface receptor for both laminin and fibronectin. In this technique, designed for rapidly exchanging equilibria, the gel filtration column is pre-equilibrated with extracellular ligand to ensure receptor occupancy during its journey through the column. Both laminin and fibronectin formed complexes with the CSAT antigen. The association with laminin was inhibited by the CSAT monoclonal antibody; the associations with both fibronectin and laminin were inhibited by synthetic peptides containing the fibronectin cell-binding sequence. Estimates of the dissociation constants by equilibrium gel filtration agree well with those available from other measurements. This suggests that these associations are biologically significant. SDS PAGE showed that all three glycoproteins comprising the CSAT antigen were present in the antigen-ligand complexes. Gel filtration and velocity sedimentation were used to show that the three bands comprise and oligomeric complex, which provides an explanation for their functional association. The inhibition of adhesion by the CSAT monoclonal antibody and the association of the purified antigen with extracellular ligands are interpreted as strongly implicating the CSAT antigen as a receptor for both fibronectin and laminin and perhaps for other extracellular molecules as well.

Separation of precursor myogenic and chondrogenic cells in early limb bud mesenchyme by a monoclonal antibody

We have addressed the problem of the segregation of cell lineages during the development of cartilage and muscle in the chick limb bud. The following experiments demonstrate that early limb buds consist of at least two independent subpopulations of committed precursor cells--those in (a) the myogenic and (b) the chondrogenic lineage--which can be physically separated. Cells obtained from stage 20, 21, and 22 limb buds were cultured for 5 h in the presence of a monoclonal antibody that was originally isolated for its ability to detach preferentially myogenic cells from extracellular matrices. The detached limb bud cells were collected and replated in normal medium. Within 2 d nearly all of the replated cells had differentiated into myoblasts and myotubes; no chondroblasts differentiated in these cultures. In contrast, the original adherent population that remained after the antibody-induced detachment of the myogenic cells differentiated largely into cartilage and was devoid of muscle. Rearing the antibody-detached cells (i.e., replicating myogenic precursors and postmitotic myoblasts) in medium known to promote chondrogenesis did not induce these cells to chondrify. Conversely, rearing the attached precursor cells (i.e., chondrogenic precursors) in medium known to promote myogenesis did not induce these cells to undergo myogenesis. The definitive mononucleated myoblasts and multinucleated myotubes were identified by muscle-specific antibodies against light meromyosin or desmin, whereas the definitive chondroblasts were identified by a monoclonal antibody against the keratan sulfate chains of the cartilage-specific sulfated proteoglycan. These findings are interpreted as supporting the lineage hypothesis in which the differentiation program of a cell is determined by means of transit through compartments of a lineage.

Adhesive multiplicity in the interaction of embryonic fibroblasts and myoblasts with extracellular matrices

Neff et al. (1982, J. Cell Biol., 95:654-666) have described a monoclonal antibody, CSAT, directed against a cell surface antigen that participates in the adhesion of skeletal muscle to extracellular matrices. We used the same antibody to compare and parse the determinants of adhesion and morphology on myogenic and fibrogenic cells. We report here that the antigen is present on skeletal and cardiac muscle and on tendon, skeletal, dermal, and cardiac fibroblasts; however, its contribution to their morphology and adhesion is different. The antibody produces large alterations in the morphology and adhesion of skeletal myoblasts and tendon fibroblasts; in contrast, its effects on the cardiac fibroblasts are not readily detected. The effects of CSAT on the other cell types, i.e., dermal and skeletal fibroblasts, cardiac muscle, 5-bromodeoxyuridine-treated skeletal muscle, lie between these extremes. The effects of CSAT on the skeletal myoblasts depends on the calcium concentration in the growth medium and on the culture age. We interpret these differential responses to CSAT as revealing differences in the adhesion of the various cells to extracellular matrices. This interpretation is supported by parallel studies using quantitative assays of cell-matrix adhesion. The likely origin of these adhesive differences is the progressive display of different kinds of adhesion-related molecules and their organizational complexes on increasingly adhesive cells. The antigen to which CSAT is directed is present on all of the above cells and thus appears to be a lowest common denominator of their adhesion to extracellular matrices.