Hidden hemorrhage: A case of idiopathic omental hemorrhage causing spontaneous hemoperitoneum.

Idiopathic omental hemorrhage (IOH) is a rare and underexplored entity in current medical literature. Most patients are male, aged 20-65 years, presenting with abdominal pain. Like most presentations of active intra-abdominal bleeding, recognition, stabilization, and definitive management are key. Expedited diagnosis and treatment of this condition is imperative as mortality rates can exceed 30% in cases due to delays of care. Presented here is a case of a young male with abdominal pain and recurrent emesis, ultimately diagnosed with bleeding from the greater omentum. He had been discharged from the emergency department the previous day. This patient's presentation highlights the importance of having high clinical suspicion for IOH in patients with recurrent or intractable nausea and emesis with persistent abdominal pain and utilizing advanced imaging for unexplained symptoms.

Using an artificial intelligence software improves emergency medicine physician intracranial haemorrhage detection to radiologist levels.

BACKGROUND: Tools to increase the turnaround speed and accuracy of imaging reports could positively influence ED logistics. The Caire ICH is an artificial intelligence (AI) software developed for ED physicians to recognise intracranial haemorrhages (ICHs) on non-contrast enhanced cranial CT scans to manage the clinical care of these patients in a timelier fashion. METHODS: A dataset of 532 non-contrast cranial CT scans was reviewed by five board-certified emergency physicians (EPs) with an average of 14.8 years of practice experience. The scans were labelled in random order for the presence or absence of an ICH. If an ICH was detected, the reader further labelled all subtypes present (ie, epidural, subdural, subarachnoid, intraparenchymal and/or intraventricular haemorrhage). After a washout period, the five EPs reviewed again the scans individually with the assistance of Caire ICH. The mean accuracy of the EP readings with AI assistance was compared with the mean accuracy of three general radiologists reading the films individually. The final diagnosis (ie, ground truth) was adjudicated by a consensus of the radiologists after their individual readings. RESULTS: Mean EP reader accuracy significantly increased by 6.20% (95% CI for the difference 5.10%-7.29%; p=0.0092) when using Caire ICH to detect an ICH. Mean accuracy of the EP cohort in detecting an ICH using Caire ICH was found to be more accurate than the radiologist cohort prior to discussion; this difference, however, was not statistically significant. CONCLUSION: The Caire ICH software significantly improved the accuracy and sensitivity of detecting an ICH by the EP to a level comparable to general radiologists. Further prospective research with larger numbers will be needed to understand the impact of Caire ICH on ED logistics and patient outcomes.

Retention and Overdose Risk among Patients Receiving Substance Use Disorder Treatment, Mental Health Care and Peer Recovery Support: A Longitudinal Analysis.

BACKGROUND: Drug overdose remains a major crisis in the United States. Expanding substance use disorder (SUD) treatment and recovery support services is critical for reducing overdose risk during disasters such as the severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) pandemic. We evaluated the outcomes of an innovative multicomponent service, inclusive of medications for SUD, and peer support, colocated in an outpatient infectious disease clinic in Baltimore City. Our goal was to examine whether a multicomponent SUD program can support patients in recovery during a pandemic. METHODS: One hundred five patients in the RESTORE service between 2019-2020 completed baseline, 3-month, and 6-month surveys. Telemedicine and phone-based support groups were implemented in March 2020 after statewide restrictions on face-to-face services due to SARS-CoV2. Data from surveys and electronic medical records were integrated and analyzed using mixed-effects regression models. RESULTS: At baseline, most patients (88%) reported using drugs/alcohol in the preceding 30 days; 48% of patients reported a history of drug overdose, as well anxiety (23%) and depression (28%) symptoms. Despite pandemic-related disruptions and procedural changes, retention in RESTORE was high (83% after 3 months, 76% after 6 months). Mixed-effects regression models indicated decreased anxiety, alcohol use, heroin use, and nonfatal overdose after 6 months of enrollment (all P < 0.05). CONCLUSIONS: Multicomponent SUD services that are colocated within infectious disease specialty services could help patients to successfully manage their overdose risk and mental health even during future disasters. This model of care could be implemented in other specialty settings that see high rates of SUD.

Validation of a tool to assess effectiveness of peer-recruitment for hepatitis C testing and linkage to care among people who inject drugs.

OBJECTIVE: People who inject drugs (PWID) have high hepatitis C virus (HCV) infection prevalence but low rates of HCV treatment uptake. To better harness the potential of peer-led social network-based interventions to increase HCV treatment uptake among PWID, simple tools that can help identify individuals with the potential to function effectively as peer-mentors who support network members to get HCV tested and linked to care are needed. METHODS: Data from a survey administered to index PWID enrolled in a social network-based intervention, in which they were invited to recruit drug use network members for HCV testing and linkage to care, was analyzed. Constructs derived from exploratory factor analysis were validated through confirmatory factor analysis (CFA). We used logistic regression analysis to assess the association between scores in identified constructs and subsequent effectiveness in the peer mentor role, defined as recruiting at least one network member for HCV testing and linkage to care in the 12 weeks following survey completion. RESULTS: Among 100 PWID with median age 53 years, 74% male, and 71% Black, CFA resulted in a multidimensional three-factor survey with 4 questions related to opinion leadership, 3 questions related to perceived HCV-related stigma, and 3 questions related to HCV communication comfort and care support willingness. Only self-designated opinion leadership was associated with effectiveness in the peer mentor role (adjusted odds ratio 3.76 (95% Confidence interval CI 1.01, 14.0)). CONCLUSION: We developed and validated a simple tool with potential to ease and improve the efficiency of peer-led social network interventions.

Impact of Co-occurring Drug Use, Hazardous Alcohol Use, and Mental Health Disorders on Drug Use Patterns in People With HIV and Hepatitis C Virus Infection.

Drug use, hazardous alcohol use, and mental health disorders are prevalent among people with HIV and hepatitis C virus (HCV) infection. Co-occurrence of alcohol use and depression negatively impacts substance use patterns. Nevertheless, HCV treatment provides a promising opportunity to identify and address co-occurring drug use, hazardous alcohol use, and mental health disorders.

Perceptions of network based recruitment for hepatitis C testing and treatment among persons who inject drugs: a qualitative exploration.

BACKGROUND: Social network interventions that take advantage of existing individual and group relationships may help overcome the significant patient, provider, and system level barriers that contribute to low hepatitis C Virus (HCV) treatment uptake among people who inject drugs (PWID). METHODS: We conducted semi-structured interviews with 20 HCV antibody positive PWID (15 male, 5 female) in Baltimore, Maryland, USA. We utilized thematic analysis and employed both inductive and deductive coding techniques to assess perceptions of barriers and facilitators of social network interventions for HCV testing, linkage to care, and treatment among PWID. RESULTS: PWID perceived a high prevalence of HCV within their social networks, especially within injection drug use networks. Overwhelmingly, participants reported a willingness to discuss HCV and provide informational, instrumental, and emotional support to their network members. Support included sharing knowledge, such as where and how to access HCV care, as well as sharing lived experiences about HCV treatment that could help peers build trust within networks. Participants who were already linked into HCV care had an increased understanding of using social network interventions to provide peer navigation, by accompanying network members to HCV related appointments. Across interviews, drug use related stigma and feeling undeserving of HCV treatment due to previous negative experiences accessing the health care system emerged as a major barrier to linkage to HCV treatment and cure. Undeservingness was often internalized and projected onto network members. To overcome this, participants supported access to low-barrier HCV treatment in alternative locations such as community-based or mobile clinics and drug treatment centers. CONCLUSION: Social network based interventions have potential to increase HCV treatment uptake among PWID. To be successful, these interventions will need to train peers to share accurate information and personal experiences with HCV testing and treatment and enhance their ability to provide support to network members who face significant stigma related to both HCV and drug use.

Factors associated with phylogenetic clustering of hepatitis C among people who inject drugs in Baltimore.

BACKGROUND: The availability of effective, oral direct acting antivirals (DAAs) for hepatitis C virus (HCV) treatment has put elimination of HCV as a public health challenge within reach. However, little is known about the characteristics of transmission networks of people who inject drugs (PWID). METHODS: Sequencing of a segment of the HCV genome was performed on samples collected from a community-based cohort of PWID between August 2005 and December 2016. Phylogenetic trees were inferred, and clusters were identified (70% bootstrap threshold; 0.04 maximum genetic distance threshold). We describe sex, race, age difference, and HIV infection status of potential transmission partners. Logistic regression was used to assess factors associated with being in an HCV cluster. RESULTS: Of 508 HCV genotype 1 viremic PWID, 8% (n = 41) were grouped into 20 clusters, consisting of 19 pairs and 1 triad. In adjusted analyses, female sex (odds ratio [OR] 2.3 [95% confidence interval (CI) 1.2-4.5]) and HIV infection (OR 5.7 [CI 2.7-11.9]) remained independently associated with being in an HCV infection cluster. CONCLUSIONS: Molecular epidemiological analysis reveals that, in this cohort of PWID in Baltimore, HIV infection and female sex were associated with HCV clustering. Combination HCV prevention interventions targeting HIV infected PWID and addressing HCV infection prevention needs of women have potential to advance HCV elimination efforts.

Hepatitis C treatment uptake among people who inject drugs in the oral direct-acting antiviral era.

BACKGROUND: Increased uptake of hepatitis C virus (HCV) treatment among people who inject drugs (PWID) will be critical to achieve HCV elimination goals. There are limited data on HCV treatment uptake among PWID recruited from community-based settings in the HCV direct-acting antiviral (DAA) era. METHODS: We analysed data from PWID with HCV newly recruited into the Baltimore, Maryland-based AIDS Linked to the IntraVenous Experience (ALIVE) cohort between 2015 and 2018. We characterized the HCV care continuum and evaluated factors associated with HCV treatment uptake. RESULTS: Of the 418 PWID with HCV, the median age was 49 years and most (88%) reported recent injection drug use (IDU). Overall, 23% had ever been evaluated by a provider for HCV treatment, 17% ever initiated DAA treatment and 13% were cured of HCV infection. Treatment uptake approximately doubled between 2015 and 2018 (13% to 26%, P = .01). In multivariable analyses, HIV infection (adjusted Odds Ratio [aOR] 2.5 [95% Confidence Interval (CI) 1.3, 4.8]), current employment (aOR 4.1 [CI 1.2, 14.4]), having a primary care provider (aOR 4.3 [CI 1.2, 14.9) and longer duration of IDU (aOR 1.3 [CI 1.1, 1.6]) were positively associated with HCV treatment. PWID with a lower annual income (≤$5000) were less likely to have initiated HCV treatment (aOR 0.5 [CI 0.3, 0.98]). CONCLUSIONS: Although HCV treatment uptake among PWID in this community-based setting in the DAA era remains suboptimal, it is encouraging that treatment uptake has increased in recent years. Innovative strategies are needed to reach all PWID infected with HCV.

Individual and network factors associated with HCV treatment uptake among people who inject drugs.

BACKGROUND: Hepatitis C virus (HCV) treatment uptake among people who inject drugs (PWID), a population with disproportionately high rates of HCV, remains low. Peers have been shown to positively impact a broad range of health outcomes for PWID. There is, however, limited data on the impact of PWID social network members on HCV treatment. METHODS: HCV-infected PWID enrolled in an ongoing community-based cohort were recruited as "indexes" to complete an egocentric social network survey. The survey elicited from the index PWID a list of their network members and the index's perception of network member characteristics. Logistic regression analyses were conducted to compare individual and network factors associated with HCV treatment in the index PWID. RESULTS: Among 540 HCV-infected PWID, the mean age was 55.7 years and the majority were black (87.2%) and male (69.8%). PWID reported a mean of 4.4 (standard deviation [SD] 3.2) network members, most of whom were relatives (mean 2.2 [SD 1.5]). In multivariable analysis, increasing index age and HIV infection were positively associated with HCV treatment, while drug use and homelessness in the preceding 6 months were negatively associated with HCV treatment. From a network perspective, having at least one network member who regularly talked with the index about seeing their doctor for HIV care was associated with HCV treatment (Adjusted Odds Ratio [AOR] 2.7; 95% Confidence Interval (CI) [1.3, 5.6]). Conversely, PWID who had at least one network member who helped them understand their HCV care were less likely to have been HCV treated (AOR 0.2; CI [0.1, 0.6). CONCLUSION: HCV treatment uptake in this group of PWID appeared to be positively influenced by discussions with network members living with HIV who were in care and negatively influenced by HCV information sharing within PWID networks. These findings underscore the influence of peers on health seeking behaviors of their network members and emphasizes the importance of well-informed peers.

Network-based recruitment of people who inject drugs for hepatitis C testing and linkage to care.

Although oral direct-acting agent (DAA) therapies have the potential to reduce the burden of hepatitis C virus (HCV) infection, treatment uptake remains low, particularly among people who inject drugs (PWID). This study examined the feasibility of an innovative peer-based recruitment strategy to engage PWID in HCV testing and treatment. We interviewed an initial set of HCV antibody-positive PWID as 'primary indexes' to gather demographic, drug use, health information and drug network characteristics. Primary indexes were then briefly educated on HCV and its treatment and encouraged to recruit their injection drug 'network members' for HCV testing and linkage to care. Eligible network members were enrolled as 'secondary indexes' and completed the same index study procedures. In sum, 17 of 36 primary indexes initiated the recruitment of 64 network members who were HCV antibody positive and eligible to become indexes. In multivariable analysis, successful recruitment of at least one network member was positively associated with prior HCV treatment (OR 2.80; CI [1.01, 7.72]), daily or more injection drug use (OR 2.38; CI [1.04, 5.47]), and a higher number of injection drug network members (OR 1.20; CI [1.01, 1.42]). Among the 69 participants with chronic HCV not previously linked to HCV care at enrolment, 91% (n = 63) completed a linkage to HCV care appointment, 45% (n = 31) scheduled an appointment with an HCV provider, and 20% (n = 14) initiated HCV therapy. These findings suggest a potential benefit for peer-driven, network-based interventions focused on HCV treatment-experienced PWID as a mechanism to increase HCV linkage to care.

Metabolic engineering of Escherichia coli for production of valerenadiene.

Valeriana officinalis is a medicinal herb which produces a suite of compounds in its root tissue useful for treatment of anxiety and insomnia. The sesquiterpene components of the root extract, valerenic acid and valerena-1,10-diene, are thought to contribute to most of the observed anxiolytic of Valerian root preparations. However, valerenic acid and its biosynthetic intermediates are only produced in low quantities in the roots of V. officinalis. Thus, in this report, Escherichia coli was metabolically engineered to produce substantial quantities of valerena-1,10-diene in shake flask fermentations with decane overlay. Expression of the wildtype valerenadiene synthase gene (pZE-wvds) resulted in production of 12µg/mL in LB cultures using endogenous FPP metabolism. Expression of a codon-optimized version of the valerenadiene synthase gene (pZE-cvds) resulted in 3-fold higher titers of valerenadiene (32µg/mL). Co-expression of pZE-cvds with an engineered methyl erythritol phosphate (MEP) pathway improved valerenadiene titers 65-fold to 2.09mg/L valerenadiene. Optimization of the fermentation medium to include glycerol supplementation enhanced yields by another 5.5-fold (11.0mg/L valerenadiene). The highest production of valerenadiene resulted from engineering the codon-optimized valerenadiene synthase gene under strong Ptrc and PT7 promoters and via co-expression of an exogenous mevalonate (MVA) pathway. These efforts resulted in an E. coli production strain that produced 62.0mg/L valerenadiene (19.4mg/L/OD600 specific productivity). This E. coli production platform will serve as the foundation for the synthesis of novel valerenic acid analogues potentially useful for the treatment of anxiety disorders.

Ferric ions accumulate in the walls of metabolically inactivating Saccharomyces cerevisiae cells and are reductively mobilized during reactivation.

Mössbauer and EPR spectra of fermenting yeast cells before and after cell wall (CW) digestion revealed that CWs accumulated iron as cells transitioned from exponential to post-exponential growth. Most CW iron was mononuclear nonheme high-spin (NHHS) Fe(III), some was diamagnetic and some was superparamagnetic. A significant portion of CW Fe was removable by EDTA. Simulations using an ordinary-differential-equations-based model suggested that cells accumulate Fe as they become metabolically inactive. When dormant Fe-loaded cells were metabolically reactivated in Fe-deficient bathophenanthroline disulfonate (BPS)-treated medium, they grew using Fe that had been mobilized from their CWs AND using trace amounts of Fe in the Fe-deficient medium. When grown in Fe-deficient medium, Fe-starved cells contained the lowest cellular Fe concentrations reported for a eukaryotic cell. During metabolic reactivation of Fe-loaded dormant cells, Fe(III) ions in the CWs of these cells were mobilized by reduction to Fe(II), followed by release from the CW and reimport into the cell. BPS short-circuited this process by chelating mobilized and released Fe(II) ions before reimport; the resulting Fe(II)(BPS)3 complex adsorbed on the cell surface. NHHS Fe(II) ions appeared transiently during mobilization, suggesting that these ions were intermediates in this process. In the presence of chelators and at high pH, metabolically inactive cells leached CW Fe; this phenomenon probably differs from metabolic mobilization. The iron regulon, as reported by Fet3p levels, was not expressed during post-exponential conditions; Fet3p was maximally expressed in exponentially growing cells. Decreased expression of the iron regulon and metabolic decline combine to promote CW Fe accumulation.

Metabolic pathways link childhood adversity to elevated blood pressure in midlife adults.

Childhood adversity is a risk factor for adult health outcomes, including obesity and hypertension. This study examines whether childhood adversity predicted mean arterial pressure through mechanisms of central obesity and leptin, adiponectin, and/or insulin resistance, and including dietary quality. 210 Black/African Americans and White/European Americans, mean age=45.8; ±3.3 years, were studied cross-sectionally. Path analyses were used to specify a chain of predictive variables in which childhood adversity predicted waist-hip ratio and dietary quality, circulating levels of hormones, and in turn, mean arterial pressure, adjusting for race, gender, and antihypertensive medications. Direct paths were found between childhood adversity, waist-hip ratio, and leptin levels and between leptin and dietary quality to mean arterial pressure. Systolic and diastolic blood pressures were similarly predicted. Early adversity appears to developmentally overload and dysregulate endocrine systems through increased risk for obesity, and through a direct impact on leptin that in turn, impacts blood pressure.

Detection of Labile Low-Molecular-Mass Transition Metal Complexes in Mitochondria.

Liquid chromatography was used with an online inductively coupled plasma mass spectrometer to detect low-molecular-mass (LMM) transition metal complexes in mitochondria isolated from fermenting yeast cells, human Jurkat cells, and mouse brain and liver. These complexes constituted 20-40% of total mitochondrial Mn, Fe, Zn, and Cu ions. The major LMM Mn complex in yeast mitochondria, called Mn1100, had a mass of ∼1100 Da and a concentration of ∼2 µM. Mammalian mitochondria contained a second Mn species with a mass of ∼2000 Da at a comparable concentration. The major Fe complex in mitochondria isolated from exponentially growing yeast cells had a mass of ∼580 Da; the concentration of Fe580 in mitochondria was ∼100 µM. When mitochondria were isolated from fermenting cells in postexponential phase, the mass of the dominant LMM Fe complex was ∼1100 Da. Upon incubation, the intensity of Fe1100 declined and that of Fe580 increased, suggesting that the two are interrelated. Mammalian mitochondria contained Fe580 and two other Fe species (Fe2000 and Fe1100) at concentrations of ∼50 µM each. The dominant LMM Zn species in mitochondria had a mass of ∼1200 Da and a concentration of ∼110 µM. Mammalian mitochondria contained a second major LMM Zn species at 1500 Da. The dominant LMM Cu species in yeast mitochondria had a mass of ∼5000 Da and a concentration in yeast mitochondria of ∼16 µM; Cu5000 was not observed in mammalian mitochondria. The dominant Co species in mitochondria, Co1200, had a concentration of 20 nM and was probably a cobalamin. Mammalian but not yeast mitochondria contained a LMM Mo species, Mo730, at a concentration of ∼1 µM. Increasing Mn, Fe, Cu, and Zn concentrations 10-fold in the medium increased the concentration of the same element in the corresponding isolated mitochondria. Treatment with metal chelators confirmed that these LMM species were labile. The dominant S species at 1100 Da was not free glutathione or glutathione disulfide.

The Human Iron-Sulfur Assembly Complex Catalyzes the Synthesis of [2Fe-2S] Clusters on ISCU2 That Can Be Transferred to Acceptor Molecules.

Iron-sulfur (Fe-S) clusters are essential protein cofactors for most life forms. In human mitochondria, the core Fe-S biosynthetic enzymatic complex (called SDUF) consists of NFS1, ISD11, ISCU2, and frataxin (FXN) protein components. Few mechanistic details about how this complex synthesizes Fe-S clusters and how these clusters are delivered to targets are known. Here circular dichroism and Mössbauer spectroscopies were used to reveal details of the Fe-S cluster assembly reaction on the SDUF complex. SDUF reactions generated [2Fe-2S] cluster intermediates that readily converted to stable [2Fe-2S] clusters bound to uncomplexed ISCU2. Similar reactions that included the apo Fe-S acceptor protein human ferredoxin (FDX1) resulted in formation of [2Fe-2S]-ISCU2 rather than [2Fe-2S]-FDX1. Subsequent addition of dithiothreitol (DTT) induced transfer of the cluster from ISCU2 to FDX1, suggesting that [2Fe-2S]-ISCU2 is an intermediate. Reactions that initially included DTT rapidly generated [2Fe-2S]-FDX1 and bypassed formation of [2Fe-2S]-ISCU2. In the absence of apo-FDX1, incubation of [2Fe-2S]-ISCU2 with DTT generated [4Fe-4S]-ISCU2 species. Together, these results conflict with a recent report of stable [4Fe-4S] cluster formation on the SDUF complex. Rather, they support a model in which SDUF builds transient [2Fe-2S] cluster intermediates that generate clusters on sulfur-containing molecules, including uncomplexed ISCU2. Additional small molecule or protein factors are required for the transfer of these clusters to Fe-S acceptor proteins or the synthesis of [4Fe-4S] clusters.

Kinetics of iron import into developing mouse organs determined by a pup-swapping method.

The kinetics of dietary iron import into various organs of mice were evaluated using a novel pup-swapping approach. Newborn pups whose bodies primarily contained (56)Fe or (57)Fe were swapped at birth such that each nursed on milk containing the opposite isotope. A pup from each litter was euthanized weekly over a 7-week period. Blood plasma was obtained, and organs were isolated typically after flushing with Ringer's buffer. (56)Fe and (57)Fe concentrations were determined for organs and plasma; organ volumes were also determined. Mössbauer spectra of equivalent (57)Fe-enriched samples were used to quantify residual blood in organs; this fraction was excluded from later analysis. Rates of import into brain, spleen, heart, and kidneys were highest during the first 2 weeks of life. In contrast, half of iron in the newborn liver exited during that time, and influx peaked later. Two mathematical models were developed to analyze the import kinetics. The only model that simulated the data adequately assumed that an iron-containing species enters the plasma and converts into a second species and that both are independently imported into organs. Consistent with this, liquid chromatography with an on-line ICP-MS detector revealed numerous iron species in plasma besides transferrin. Model fitting required that the first species, assigned to non-transferrin-bound iron, imports faster into organs than the second, assigned to transferrin-bound-iron. Non-transferrin-bound iron rather than transferrin-bound-iron appears to play the dominant role in importing iron into organs during early development of healthy mice.

Speciation of iron in mouse liver during development, iron deficiency, IRP2 deletion and inflammatory hepatitis.

The iron content of livers from (57)Fe-enriched C57BL/6 mice of different ages were investigated using Mössbauer spectroscopy, electron paramagnetic resonance (EPR), electronic absorption spectroscopy and inductively coupled plasma mass spectrometry (ICP-MS). About 80% of the Fe in an adult liver was due to blood; thus removal of blood by flushing with buffer was essential to observe endogenous liver Fe. Even after exhaustive flushing, ca. 20% of the Fe in anaerobically dissected livers was typical of deoxy-hemoglobin. The concentration of Fe in newborn livers was the highest of any developmental stage (∼1.2 mM). Most was stored as ferritin, with little mitochondrial Fe (consisting primarily of Fe-S clusters and haems) evident. Within the first few weeks of life, about half of ferritin Fe was mobilized and exported, illustrating the importance of Fe release as well as Fe storage in liver function. Additional ferritin Fe was used to generate mitochondrial Fe centres. From ca. 4 weeks of age to the end of the mouse's natural lifespan, the concentration of mitochondrial Fe in liver was essentially invariant. A minor contribution from nonhaem high-spin Fe(II) was observed in most liver samples and was also invariant with age. Some portion of these species may constitute the labile iron pool. Livers from mice raised on an Fe-deficient diet were highly Fe depleted; they were devoid of ferritin and contained 1/3 as much mitochondrial Fe as found in Fe-sufficient livers. In contrast, brains of the same Fe-deficient mice retained normal levels of mitochondrial Fe. Livers from mice with inflammatory hepatitis and from IRP2(-/-) mice hyper-accumulated Fe. These livers had high ferritin levels but low levels of mitochondrial Fe.

High-spin ferric ions in Saccharomyces cerevisiae vacuoles are reduced to the ferrous state during adenine-precursor detoxification.

The majority of Fe in Fe-replete yeast cells is located in vacuoles. These acidic organelles store Fe for use under Fe-deficient conditions and they sequester it from other parts of the cell to avoid Fe-associated toxicity. Vacuolar Fe is predominantly in the form of one or more magnetically isolated nonheme high-spin (NHHS) Fe(III) complexes with polyphosphate-related ligands. Some Fe(III) oxyhydroxide nanoparticles may also be present in these organelles, perhaps in equilibrium with the NHHS Fe(III). Little is known regarding the chemical properties of vacuolar Fe. When grown on adenine-deficient medium (A↓), ADE2Δ strains of yeast such as W303 produce a toxic intermediate in the adenine biosynthetic pathway. This intermediate is conjugated with glutathione and shuttled into the vacuole for detoxification. The iron content of A↓ W303 cells was determined by Mössbauer and EPR spectroscopies. As they transitioned from exponential growth to stationary state, A↓ cells (supplemented with 40 µM Fe(III) citrate) accumulated two major NHHS Fe(II) species as the vacuolar NHHS Fe(III) species declined. This is evidence that vacuoles in A↓ cells are more reducing than those in adenine-sufficient cells. A↓ cells suffered less oxidative stress despite the abundance of NHHS Fe(II) complexes; such species typically promote Fenton chemistry. Most Fe in cells grown for 5 days with extra yeast-nitrogen-base, amino acids and bases in minimal medium was HS Fe(III) with insignificant amounts of nanoparticles. The vacuoles of these cells might be more acidic than normal and can accommodate high concentrations of HS Fe(III) species. Glucose levels and rapamycin (affecting the TOR system) affected cellular Fe content. This study illustrates the sensitivity of cellular Fe to changes in metabolism, redox state and pH. Such effects broaden our understanding of how Fe and overall cellular metabolism are integrated.

Mössbauer, EPR, and modeling study of iron trafficking and regulation in Δccc1 and CCC1-up Saccharomyces cerevisiae.

Strains lacking and overexpressing the vacuolar iron (Fe) importer CCC1 were characterized using Mössbauer and EPR spectroscopies. Vacuolar Fe import is impeded in Δccc1 cells and enhanced in CCC1-up cells, causing vacuolar Fe in these strains to decline and accumulate, respectively, relative to WT cells. Cytosolic Fe levels should behave oppositely. The Fe content of Δccc1 cells grown under low-Fe conditions was similar to that in WT cells. Most Fe was mitochondrial with some nonheme high spin (NHHS) Fe(II) present. Δccc1 cells grown with increasing Fe concentration in the medium contained less total Fe, less vacuolar HS Fe(III), and more NHHS Fe(II) than in comparable WT cells. As the Fe concentration in the growth medium increased, the concentration of HS Fe(III) in Δccc1 cells increased to just 60% of WT levels, while NHHS Fe(II) increased to twice WT levels, suggesting that the NHHS Fe(II) was cytosolic. Δccc1 cells suffered more oxidative damage than WT cells, suggesting that the accumulated NHHS Fe(II) promoted Fenton chemistry. The Fe concentration in CCC1-up cells was higher than in WT cells; the extra Fe was present as NHHS Fe(II) and Fe(III) and as Fe(III) oxyhydroxide nanoparticles. These cells contained less mitochondrial Fe and exhibited less ROS damage than Δccc1 cells. CCC1-up cells were adenine-deficient on minimal medium; supplementing with adenine caused a decline of NHHS Fe(II) suggesting that some of the NHHS Fe(II) that accumulated in these cells was associated with adenine deficiency rather than the overexpression of CCC1. A mathematical model was developed that simulated changes in Fe distributions. Simulations suggested that only a modest proportion of the observed NHHS Fe(II) in both strains was the cytosolic form of Fe that is sensed by the Fe import regulatory system. The remainder is probably generated by the reduction of the vacuolar NHHS Fe(III) species.

Coping and social problem solving correlates of asthma control and quality of life.

In a sample of adults with asthma receiving care and medication in an outpatient pulmonary clinic, this study tested for statistical associations between social problem-solving styles, asthma control, and asthma-related quality of life. These variables were measured cross sectionally as a first step toward more systematic application of social problem-solving frameworks in asthma self-management training. Recruitment occurred during pulmonology clinic service hours. Forty-four adults with physician-confirmed diagnosis of asthma provided data including age, gender, height, weight, race, income, and comorbid conditions. The Asthma Control Questionnaire, the Mini Asthma Quality of Life Questionnaire (Short Form), and peak expiratory force measures offered multiple views of asthma health at the time of the study. Maladaptive coping (impulsive and careless problem-solving styles) based on transactional stress models of health were assessed with the Social Problem-Solving Inventory-Revised: Short Form. Controlling for variance associated with gender, age, and income, individuals reporting higher impulsive-careless scores exhibited significantly lower scores on asthma control (ß = 0.70, p = 0.001, confidence interval (CI) [0.37-1.04]) and lower asthma-related quality of life (ß = 0.79, p = 0.017, CI [0.15-1.42]). These findings suggest that specific maladaptive problem-solving styles may uniquely contribute to asthma health burdens. Because problem-solving coping strategies are both measureable and teachable, behavioral interventions aimed at facilitating adaptive coping and problem solving could positively affect patient's asthma management and quality of life.