The Imipridone ONC213 Targets α-Ketoglutarate Dehydrogenase to Induce Mitochondrial Stress and Suppress Oxidative Phosphorylation in Acute Myeloid Leukemia

Eradication of acute myeloid leukemia (AML) is therapeutically challenging; many patients succumb to AML despite initially responding to conventional treatments. Here, we showed that the imipridone ONC213 elicits potent antileukemia activity in a subset of AML cell lines and primary patient samples, particularly in leukemia stem cells, while producing negligible toxicity in normal hematopoietic cells. ONC213 suppressed mitochondrial respiration and elevated α-ketoglutarate by suppressing α-ketoglutarate dehydrogenase (αKGDH) activity. Deletion of OGDH, which encodes αKGDH, suppressed AML fitness and impaired oxidative phosphorylation, highlighting the key role for αKGDH inhibition in ONC213-induced death. ONC213 treatment induced a unique mitochondrial stress response and suppressed de novo protein synthesis in AML cells. Additionally, ONC213 reduced the translation of MCL1, which contributed to ONC213-induced apoptosis. Importantly, a patient-derived xenograft from a relapsed AML patient was sensitive to ONC213 in vivo. Collectively, these findings support further development of ONC213 for treating AML.

SIGNIFICANCE

In AML cells, ONC213 suppresses αKGDH, which induces a unique mitochondrial stress response, and reduces MCL1 to decrease oxidative phosphorylation and elicit potent antileukemia activity. See related commentary by Boët and Sarry, p. 950.

Enhancing anti-AML activity of venetoclax by isoflavone ME-344 through suppression of OXPHOS and/or purine biosynthesis in vitro

Venetoclax (VEN), in combination with low dose cytarabine (AraC) or a hypomethylating agent, is FDA approved to treat acute myeloid leukemia (AML) in patients who are over the age of 75 or cannot tolerate standard chemotherapy. Despite high response rates to these therapies, most patients succumb to the disease due to relapse and/or drug resistance, providing an unmet clinical need for novel therapies to improve AML patient survival. ME-344 is a potent isoflavone with demonstrated inhibitory activity toward oxidative phosphorylation (OXPHOS) and clinical activity in solid tumors. Given that OXPHOS inhibition enhances VEN antileukemic activity against AML, we hypothesized that ME-344 could enhance the anti-AML activity of VEN. Here we report that ME-344 enhanced VEN to target AML cell lines and primary patient samples while sparing normal hematopoietic cells. Cooperative suppression of OXPHOS was detected in a subset of AML cell lines and primary patient samples. Metabolomics analysis revealed a significant reduction of purine biosynthesis metabolites by ME-344. Further, lometrexol, a purine biosynthesis inhibitor, synergistically enhanced VEN-induced apoptosis in AML cell lines. Interestingly, AML cells with acquired AraC resistance showed significantly increased purine biosynthesis metabolites and sensitivities to ME-344. Furthermore, synergy between ME-344 and VEN was preserved in these AraC-resistant AML cells. In vivo studies revealed significantly prolonged survival upon combination therapy of ME-344 and VEN in NSGS mice bearing parental or AraC-resistant MV4-11 leukemia compared to the vehicle control. This study demonstrates that ME-344 enhances VEN antileukemic activity against preclinical models of AML by suppressing OXPHOS and/or purine biosynthesis.

Acquired resistance to venetoclax plus azacitidine in acute myeloid leukemia: In vitro models and mechanisms

The combination of venetoclax (VEN) and azacitidine (AZA) has become the standard of care for acute myeloid leukemia (AML) patients who are ≥ 75 years or unfit for intensive chemotherapy. Though initially promising, resistance to the combination therapy is an issue and VEN + AZA-relapsed/refractory patients have dismal outcomes. To better understand the mechanisms of resistance, we developed VEN + AZA-resistant AML cell lines, MV4-11/VEN + AZA-R and ML-2/VEN + AZA-R, which show > 300-fold persistent resistance compared to the parental lines. We demonstrate that these cells have unique metabolic profiles, including significantly increased levels of cytidine triphosphate (CTP) and deoxycytidine triphosphate (dCTP), changes in fatty acid and amino acid metabolism and increased utilization and reliance on glycolysis. Furthermore, fatty acid transporter CD36 is increased in the resistant cells compared to the parental cells. Inhibition of glycolysis with 2-Deoxy-D-glucose re-sensitized the resistant cells to VEN + AZA. In addition, the VEN + AZA-R cells have increased levels of the antiapoptotic protein Mcl-1 and decreased levels of the pro-apoptotic protein Bax. Overexpression of Mcl-1 or knockdown of Bax result in resistance to VEN + AZA. Our results provide insight into the molecular mechanisms contributing to VEN + AZA resistance and assist in the development of novel therapeutics to overcome this resistance in AML patients.

Enhancing anti-AML activity of venetoclax by isoflavone ME-344 through suppression of OXPHOS and/or purine biosynthesis

Venetoclax (VEN), in combination with low dose cytarabine (AraC) or a hypomethylating agent, is FDA approved to treat acute myeloid leukemia (AML) in patients who are over the age of 75 or cannot tolerate standard chemotherapy. Despite high response rates to these combination therapies, most patients succumb to the disease due to relapse and/or drug resistance, providing an unmet clinical need for novel therapies to improve AML patient survival. ME-344 is a potent isoflavone with demonstrated inhibitory activity toward oxidative phosphorylation (OXPHOS) and clinical activity in solid tumors. Given that OXPHOS inhibition enhances VEN antileukemic activity against AML, we hypothesized that ME-344 could enhance the anti-AML activity of VEN. Here we report that ME-344 synergized with VEN to target AML cell lines and primary patient samples while sparing normal hematopoietic cells. Cooperative suppression of OXPHOS was detected in a subset of AML cell lines and primary patient samples. Metabolomics analysis revealed a significant reduction of purine biosynthesis metabolites by ME-344. Further, lometrexol, an inhibitor of purine biosynthesis, synergistically enhanced VEN-induced apoptosis in AML cell lines. Interestingly, AML cells with acquired resistance to AraC showed significantly increased purine biosynthesis metabolites and sensitivities to ME-344. Furthermore, synergy between ME-344 and VEN was preserved in these AraC-resistant AML cells. These results translated into significantly prolonged survival upon combination of ME-344 and VEN in NSGS mice bearing parental or AraC-resistant MV4-11 leukemia. This study demonstrates that ME-344 enhances VEN antileukemic activity against preclinical models of AML by suppressing OXPHOS and/or purine biosynthesis.

Associations between saturated fatty acids from different dietary sources and cardiovascular disease risk in 114,285 UK Biobank study participants

Background

Previous studies suggest that different foods rich in saturated fatty acids (SFA), particularly meat and dairy, have diverging directions of association with risks of total cardiovascular disease (CVD) and CVD subtypes.(1,2)

Purpose

To investigate the associations between SFA from different dietary sources and risks of total CVD, ischaemic heart disease (IHD), and stroke.

Methods

We analysed data on 114,285 UK Biobank participants who had completed ≥2 24-h dietary assessments and were free of CVD at the date of the latest 24-h dietary assessment. Risks of incident (non-fatal and fatal) total CVD, IHD and stroke by intakes of SFA from different sources were estimated using multivariable Cox regressions. Additional models assessed the role of body mass index (BMI) and low-density lipoprotein cholesterol (LDL-C) as potential mediators. We also estimated the associations between modelled isoenergetic substitution of 5% energy from SFA from meat with SFA from dairy, polyunsaturated fatty acids, monounsaturated fatty acids, carbohydrates from whole grains and carbohydrates from fruit and vegetables, and risk of CVD outcomes. A false discovery rate controlling procedure was used to account for multiple testing.

Results

Over a median 8.5 years of follow-up, there were 4,365, 3,394, and 1,041 cases of total CVD, IHD and stroke, respectively. There were no significant associations between total SFA intake and CVD outcomes. SFA from meat was positively associated with total CVD (hazard ratio for each 5% of energy, 1.19; 95% CI, 1.05–1.35) and IHD (1.21; 1.05–1.39) risk independently of lifestyle and cardiovascular risk factors. However, the estimates were attenuated and non-significant for both total CVD (1.11; 0.98–1.26) and IHD (1.12; 0.97–1.29) after adjustment for BMI. SFA from dairy was inversely associated with IHD risk (0.89; 0.82–0.96) in the multivariable model, however this finding was also attenuated after adjustment for BMI and did not pass correction for multiple testing (0.91; 0.84 to 0.98). Modelled replacement of 5% of energy from SFA from meat with carbohydrates from whole grains or carbohydrates from fruit and vegetables were associated with lower risk of stroke in the multivariable model (0.86; 0.78–0.94 & 0.86; 0.78–0.95, respectively) and the model adjusted for BMI and LDL-C (0.87; 0.79–0.96 & 0.86; 0.78–0.95, respectively).

Conclusion(s)

SFA from meat was associated with a higher risk of total CVD and IHD, while SFA from dairy was associated with lower risk of IHD, although BMI seemed to account for a large proportion of these associations. It is possible that diverging associations of SFA from different sources with CVD risk may explain the overall null association with total SFA observed in this study and some previous observational studies. Randomised controlled trials are needed to confirm whether replacing SFA from meat by carbohydrate from wholegrains or fruit and vegetables may be beneficial in reducing stroke risk.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Clarendon Fund and Jesus College Clarendon Old Members' AwardJesus College Graduate Scholarship

Targeting multiple signaling pathways: the new approach to acute myeloid leukemia therapy

Acute myeloid leukemia (AML) is the most common form of acute leukemia in adults and the second most common form of acute leukemia in children. Despite this, very little improvement in survival rates has been achieved over the past few decades. This is partially due to the heterogeneity of AML and the need for more targeted therapeutics than the traditional cytotoxic chemotherapies that have been a mainstay in therapy for the past 50 years. In the past 20 years, research has been diversifying the approach to treating AML by investigating molecular pathways uniquely relevant to AML cell proliferation and survival. Here we review the development of novel therapeutics in targeting apoptosis, receptor tyrosine kinase (RTK) signaling, hedgehog (HH) pathway, mitochondrial function, DNA repair, and c-Myc signaling. There has been an impressive effort into better understanding the diversity of AML cell characteristics and here we highlight important preclinical studies that have supported therapeutic development and continue to promote new ways to target AML cells. In addition, we describe clinical investigations that have led to FDA approval of new targeted AML therapies and ongoing clinical trials of novel therapies targeting AML survival pathways. We also describe the complexity of targeting leukemia stem cells (LSCs) as an approach to addressing relapse and remission in AML and targetable pathways that are unique to LSC survival. This comprehensive review details what we currently understand about the signaling pathways that support AML cell survival and the exceptional ways in which we disrupt them.

Targeting mitochondrial respiration for the treatment of acute myeloid leukemia

Acute myeloid leukemia (AML) is a heterogeneous disease with variable presentation, molecular phenotype, and cytogenetic abnormalities and has seen very little improvement in patient survival over the last few decades. This heterogeneity supports poor prognosis partially through the variability in response to the standard chemotherapy. Further understanding of molecular heterogeneity has promoted the development of novel treatments, some of which target mitochondrial metabolism and function. This review discusses the relative dependency that AML cells have on mitochondrial function, and the ability to pivot this reliance to target important subsets of AML cells, including leukemia stem cells (LSCs). LSCs are tumor-initiating cells that are resistant to standard chemotherapy and promote the persistence and relapse of AML. Historically, LSCs have been targeted based on immunophenotype, but recent developments in the understanding of LSC metabolism has demonstrated unique abilities to target LSCs while sparing normal hematopoietic stem cells (HSCs) through inhibition of mitochondrial function. Here we highlight the use of small molecules that have been demonstrated to effectively target mitochondrial function. IACS-010759 and ME-344 target the electron transport chain (ETC) to inhibit oxidative phosphorylation (OXPHOS). The imipridone family (ONC201, ONC206, ONC212) of inhibitors target mitochondria through activation of ClpP mitochondrial protease and reduce function of essential pathways. These molecules offer a new mechanism for developing clinical therapies in AML and support novel strategies to target LSCs in parallel with conventional therapies.

Three-dimensional alginate hydrogels for radiobiological and metabolic studies of cancer cells

The purpose of this study is to demonstrate calcium alginate hydrogels as a system for in vitro radiobiological and metabolic studies of cancer cells. Previous studies have established calcium alginate as a versatile three-dimensional (3D) culturing system capable of generating areas of oxygen heterogeneity and modeling metabolic changes in vitro. Here, through dosimetry, clonogenic and viability assays, and pimonidazole staining, we demonstrate that alginate can model radiobiological responses that monolayer cultures do not simulate. Notably, alginate hydrogels with radii greater than 500 μm demonstrate hypoxic cores, while smaller hydrogels do not. The size of this hypoxic region correlates with hydrogel size and improved cell survival following radiation therapy. Hydrogels can also be utilized in hyperpolarized magnetic resonance spectroscopy and extracellular flux analysis. Alginate therefore offers a reproducible, consistent, and low-cost means for 3D culture of cancer cells for radiobiological studies that simulates important in vivo parameters such as regional hypoxia and enables long-term culturing and in vitro metabolic studies.

Associations of stream geomorphic conditions and prevalence of alternative reproductive tactics among sockeye salmon populations

In many species, males may exhibit alternative life histories to circumvent the costs of intrasexual competition and female courtship. While the evolution and underlying genetic and physiological mechanisms behind alternative reproductive tactics are well studied, there has been less consideration of the ecological factors that regulate their prevalence. Here, we examine six decades of age composition records from thirty-six populations of sockeye salmon (Oncorhynchus nerka) to quantify associations between spawning habitat characteristics and the prevalence of precocious sneakers known as 'jacks'. Jack prevalence was independent of neutral genetic structure among stream populations, but varied among habitat types and as a function of continuous geomorphic characteristics. Jacks were more common in streams relative to beaches and rivers, and their prevalence was negatively associated with stream width, depth, elevation, slope and area, but positively related to bank cover. Behavioural observations showed that jacks made greater use of banks, wood and shallows than guard males, indicating that their reproductive success depends on the availability of such refuges. Our results emphasize the role of the physical habitat in shaping reproductive tactic frequencies among populations, likely through local adaptation in response to variable fitness expectations under different geomorphic conditions.

Abstract 833: Alginate hydrogels for three-dimensional culture and real-time monitoring of cancer cell metabolism and radiation response

The purpose of this study was to characterize a three-dimensional calcium alginate culture system for real-time monitoring of cancer cell metabolism and radiation response. HCT116 colorectal cancer cells were encapsulated in 2.5% calcium alginate using a custom electrostatic rig adapted from a previously published system. Bead diameter was a function of voltage and alginate concentration: 4 x 107 cells/mL encapsulated at 4 and 8 kV resulted in mean diameters of 880 and 584 µm, respectively. The distribution of bead radii for all voltages showed positive excess kurtosis (4 kV = 1.6, 8 kV = 3.0) and 72.9% of 4 kV and 77.2% of 8 kV bead diameters fell within one standard deviation of the mean. Encapsulated cell viability was assessed by staining with Trypan Blue and clonogenic survival assays (CSAs). The baseline viability of cells immediately after encapsulation was 93.2%, which decreased 2 days after a single 10 Gy dose (90.7%, p<0.05). After two weeks of continuous culturing, 84.1% of non-irradiated and 73.8% of irradiated encapsulated cells remained viable (p<0.003). Pimonidazole staining demonstrated the presence of hypoxic cores proportional to bead size. CSAs of 8 kV beads showed a dose modifying factor (DMF) of 1.06 relative to cells grown in a monolayer, while larger 4 kV beads showed a DMF of 1.58. Mean oxygen consumption rate rose with increasing number of 8 kV beads/well: 1 bead, 35.5; 2 beads, 97.4; 3 beads, 175.5; 4 beads, 209.9; 2.0 x 104 monolayer cells, 92.6 (all pmol/min, ~8.2 x103 cells/bead, p<0.005). Hyperpolarized 13C-NMR spectroscopy of 400 uL of 8 kV beads containing 1.2 x 108 cells/mL showed a detectable conversion of [1-13C]-pyruvate to [1-13C]-lactate; 1 hour after a single 10 Gy dose, the lactate:pyruvate ratio decreased by 25%. Unpaired 2-tailed Student’s t-tests were used to determine significance between and one-way ANOVA was used to determine significance among groups with α set at p≤0.05. These data demonstrate the versatility of alginate hydrogels for real-time metabolic and radiation response studies which are non-invasive, higher throughput, and lower cost compared to in vivo systems. Future directions include additional metabolic flux analysis and hyperpolarized 13C-NMR spectroscopy to further investigate the cancer cell metabolic response to drug and/or radiation therapy.

Citation Format: Aparna H. Kesarwala, Jenna L. Carter, Graham H. Read, Natsuko Miura, Kazutoshi Yamamoto, James B. Mitchell, Murali C. Krishna. Alginate hydrogels for three-dimensional culture and real-time monitoring of cancer cell metabolism and radiation response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 833. doi:10.1158/1538-7445.AM2017-833

Enhanced production of human influenza virus in PBS-12SF cells with a reduced interferon response

Influenza is one of the most important infectious diseases in humans. The best way to prevent severe illness caused by influenza infection is vaccination. Cell culture-derived influenza vaccines are being considered in addition to the widely used egg-based system in order to support the increasing seasonal demand and to be prepared in case of a pandemic. Cell culture based systems offer increased safety, capacity, and flexibility with reduced downstream processing relative to embryonated eggs. We have previously reported a chick embryo cell line, termed PBS-12SF, that supports replication of human and avian influenza A viruses to high titers (>10(7) PFU/ml) without the need for exogenous proteases or serum proteins. Viral infections in cells are limited by the Interferon (IFN) response typified by production of type I IFNs that bind to the IFNα/β receptor and activate an antiviral state. In this study, we investigated how neutralizing the interferon (IFN) response in PBS-12SF cells, via shRNA-mediated knock-down of IFNAR1 mRNA expression, affects influenza virus production. We were successful in knocking down ∼90% of IFNAR1 protein expression by this method, resulting in a significant decrease in the response to recombinant chIFNα stimulation in PBS-12SF cells as shown by a reduction in expression of interferon-responsive genes when compared to control cells. Additionally; IFNAR1-knock-down cells displayed enhanced viral HA production and released more virus into cell culture supernatants than parental PBS-12SF cells.

Estimating glomerular filtration rate: comparison of the CKD-EPI and MDRD equations in a large UK cohort with particular emphasis on the effect of age

BACKGROUND

The chronic kidney disease (CKD)-Epidemiology Collaboration (CKD-EPI) equation was developed to address the underestimation of measured glomerular filtration rate (GFR) by the Modification of Diet in Renal Disease (MDRD) equation at levels >60 mL/min/1.73 m(2).

AIM

To assess the impact of the CKD-EPI equation on the estimation of GFR in a large adult UK population (n = 561,400), particularly looking at the effect of age.

DESIGN

Serum creatinine results (ID-MS-aligned enzymatic assay) were extracted from the pathology database during 1 year on adult (≥ 18 years) patients from primary care.

METHODS

The first available creatinine result from 174,448 people was used to estimate GFR using both equations and agreement assessed.

RESULTS

Median CKD-EPI GFR was significantly higher than median MDRD GFR (82 vs. 76 mL/min/1.73 m(2), P < 0.0001). Overall mean bias between CKD-EPI and MDRD GFR was 5.0%, ranging from 13.0% in the 18-29 years age group down to -7.5% in those aged ≥ 90 years. Although statistically significant at all age groups the difference diminished with age and the agreement in GFR category assignment increased. Age-adjusted population prevalence of CKD Stages 3-5 was lower by CKD-EPI than by MDRD (4.4% vs. 4.9%).

CONCLUSION

CKD-EPI produces higher GFR and lower CKD estimates, particularly among 18-59 year age groups with MDRD estimated GFRs of 45-59 mL/min/1.73 m(2) (Stage 3A). However, at ages >70 years there is very little difference between the equations, and among the very elderly CKD-EPI may actually increase CKD prevalence estimates.

The effect of diet fed to lambs on subsequent development of Trichostrongylus colubriformis larvae in vitro and on pasture

Contrasting herbage diets were fed to lambs to evaluate their effect on subsequent development of Trichostrongylus colubriformis larvae in faeces and on pasture. The diets had either no condensed tannin (CT), lucerne (Medicago sativa cv. Otaio), white clover (Trifolium repens cv. Tahora), or had moderate to high concentrations of CT, sulla (Hedysarum coronarium cv. Grassland Aokau), Lotus corniculatus (cv. Grasslands Goldie), L. pedunculatus (cv. Grassland Maku), Dorycnium pentophyllum, and Dorycnium rectum. Trials were carried out in summer (warm) and in autumn (cool and moist). In summer, egg viability was evaluated in vitro with egg hatch and larval development assays. In both seasons faeces were placed on pasture to compare recovery of eggs and larvae from faeces and larvae from herbage on the high and low fertility farmlets on the AgResearch Ballantrae Hill Country Research Station. D. rectum and D. pentophyllum diets decreased (P<0.01) egg hatching and larval development in laboratory assays relative to other diets. In summer, the number of larvae recovered from faeces placed on pasture was far greater (P<0.001) if the lambs had been fed lucerne than any other diet, whereas recovery was always lowest from faeces of sheep fed D. rectum and D. pentophyllum. Although dietary differences were lower in autumn than in summer, larval recoveries were lower (P<0.05) from faeces of lambs fed D. rectum and L. corniculatus than from white clover, lucerne and sulla diets. This study indicates that the diet of the host can have a significant impact on egg hatching and the subsequent development of T. colubriformis larvae in the laboratory and in the field. In particular, D. rectum consistently reduced T. colubriformis development. Effects measured in vitro generally under-estimated effects measured under field conditions.

Ultrasound features of osteosarcoma of the mandible--a first report

Ultrasound imaging is becoming widely used in the head and neck region as a first-line investigation to assess soft tissue swellings. Clinicians should be aware of the potential of diagnostic ultrasound to identify important signs of malignant disease involving bone. Involvement of the mandible by osteosarcoma is uncommon. A young adult patient presented with facial swelling and an apparently infected lower third molar extraction socket. Subtle signs were missed on dental radiographs. Diagnostic ultrasound investigation was pivotal in identifying sinister signs: namely, soft tissue mass associated with bone thinning, erosion, expansion, and the "sunray" appearance of the buccal cortex, which were suggestive of osteosarcoma. These findings enabled priority to be given to subsequent investigations using other modalities. We present a first report of the ultrasound features of osteosarcoma of the mandible and consider this to be a useful modality in an initial investigation.

Effect of mutations in Pneumocystis carinii dihydropteroate synthase gene on outcome of P carinii pneumonia in patients with HIV-1: a prospective study

BACKGROUND

Investigators have reported that patients infected with Pneumocystis carinii containing mutations in the DHPS (dihydropteroate synthase) gene have a worse outcome than those infected with P carinii containing wild-type DHPS. We investigated patients with HIV-1 infection and P carinii pneumonia to determine if DHPS mutations were associated with poor outcomes in these patients.

METHODS

We compared presence of mutations at the DHPS locus with survival and response of patients to co-trimoxazole or other drugs.

FINDINGS

For patients initially given co-trimoxazole, nine (14%) of 66 with DHPS mutant died, compared with nine (25%) of 36 with wild type (risk ratio50.55 [95% CI=0.24-1.25]; p=0.15). Ten (15%) of 66 patients with a DHPS mutant did not respond to treatment, compared with 13 (36%) of 36 patients with the wild type (0.42 [0.20-0.86]; p=0.02). For patients aged 40 years or older, four (14%) of 29 with the mutant and nine (56%) of 16 with the wild type died (0.25 [0.09-0.67]; p=0.005).

INTERPRETATION

These results, by contrast with those of previous studies, suggest that patients with wild-type P carinii do not have a better outcome than patients with the mutant when given co-trimoxazole. Our results suggest that presence of a DHPS mutation should be only one of several criteria guiding the choice of initial drug treatment of P carinii pneumonia in patients with HIV-1 infection.

Metachronous bilateral primary adenocarcinoma of the submandibular glands

A young woman developed an unusual adenocarcinoma in each submandibular salivary gland at an interval of 30 months. This presentation has not been described previously. The possible etiology for this and treatment options are discussed. The choice of diagnostic imaging (ultrasound versus magnetic resonance imaging) is highlighted. As a result of regular follow-ups using diagnostic ultrasound, a second tumor was observed to reach a dimension of 8 mm in less than 6 months. This is probably the first report documenting the extent of initial growth of this rare tumor.

Sulfa or sulfone prophylaxis and geographic region predict mutations in the Pneumocystis carinii dihydropteroate synthase gene

To determine factors associated with mutations in the Pneumocystis carinii dihydropteroate synthase (DHPS) gene, a prospective study of human immunodeficiency virus (HIV)-infected patients with confirmed P. carinii pneumonia was conducted in Atlanta, Seattle, and San Francisco. Clinical information was obtained from patient interview and chart abstraction. DHPS genotype was determined from DNA sequencing. Overall, 76 (68.5%) of 111 patients had a mutant DHPS genotype, including 22 (81.5%) of 27 patients from San Francisco. In multivariate analysis, sulfa or sulfone prophylaxis and study site were independent predictors of a mutant genotype. Fourteen (53.8%) of 26 patients who were newly diagnosed with HIV infection and had never taken prophylaxis had a mutant genotype. The significance of geographic location as a risk factor for mutant genotype and the high proportion of mutant genotypes among persons never prescribed prophylaxis, including those newly diagnosed with HIV infection, provide indirect evidence that these mutations are transmitted from person to person either directly or through a common environmental source.

Activity of ABT-773 against Mycobacterium avium complex in the beige mouse model

ABT-773, a new ketolide antimicrobial agent, was evaluated in comparison to clarithromycin (CLA) in vitro against Mycobacterium avium complex (MAC) and in a beige mouse model of disseminated MAC infection. The MICs at which 50 and 90% of the isolates tested were inhibited were 2 and 4 microg/ml, respectively, for CLA and 8 and 16 microg/ml, respectively, for ABT-773. Eight CLA-resistant isolates were found to be resistant to ABT-773 (MICs > 64 microg/ml). In the in vivo study mice were treated with ABT-773 (50, 100, and 200 mg/kg of body weight) or CLA (200 mg/kg). Both ABT-773 (100 and 200 mg/kg) and CLA significantly decreased the viable cell counts in spleens and lungs. ABT-773 (200 mg/kg) and CLA had similar activities in lungs, but the former was more active in spleens.

VMN hypothalamic dopamine and serotonin in anorectic septic rats

During sepsis, catabolism of proteins and associated changes in plasma amino acids occur. Tryptophan and tyrosine, and their derivatives serotonin (5-HT) and dopamine (DA), influence hypothalamic feeding-related areas and are associated with the onset of anorexia. We hypothesized that anorexia of sepsis is associated with changes in serotonin and dopamine in the ventromedial nucleus (VMN) of the hypothalamus. The aim of this study was to test our hypothesis by measuring intra-VMN changes of these two neurotransmitters at the onset of anorexia during sepsis. Fischer 344 male rats had an intracerebral guide cannula stereotaxically implanted into the VMN. Ten days later, in awake, overnight-food-deprived rats, a microdialysis probe was inserted through the in situ VMN cannula. Two hours thereafter, serial baseline serotonin and dopamine concentrations were measured. Then cecal ligation and puncture to induce sepsis or a control laparotomy was performed under isoflurane anesthesia. VMN microdialysis samples were serially collected every 30 min for 8 h after the surgical procedure to determine 5-HT and DA changes in response to sepsis. During the hypermetabolic response to sepsis, a strong association occurred between anorexia and a significant reduction of VMN dopamine concentration (P < 0.05; constant rate of dopamine decrease in the Study group of 0.99 pg per 2 h); no changes occurred in 5-HT in association with anorexia of sepsis. Six hours after operation, a single meal was offered for 20 min to assess the response of neurotransmitters to food ingestion. Food intake was minimal in anorectic septic rats (mean size of the after food-deprived meal in the Septic group was 0.03+/-0.01 g, that of the Control group was 1.27+/-0.14 g; P = 0.0001), while Control rats demonstrated anticipated changes in neurotransmitters in response to eating. We conclude that the onset of anorexia in septic rats is associated with a reduction in VMN dopamine.

Nursing considerations in support of a patient pursuing his dream

A 30-year-old man with end stage renal disease (ESRD) undergoing thrice weekly hemodialysis set out to achieve a personal goal to ride his bicycle across the United States within 30 days. To support patients in achieving such a goal, nephrology nurses must consider not only nutritional components, but must be prepared to deal with the physical challenges that face patients in the daily struggles struggle to reach their goal. It became a priority and a challenge for the nephrology team to treat this young man as an athlete who also happened to have ESRD, rather than as a dialysis patient who was a cyclist.

Genetic variation in Pneumocystis carinii isolates from different geographic regions: implications for transmission

To study transmission patterns of Pneumocystis carinii pneumonia (PCP) in persons with AIDS, we evaluated P. carinii isolates from patients in five U.S. cities for variation at two independent genetic loci, the mitochondrial large subunit rRNA and dihydropteroate synthase. Fourteen unique multilocus genotypes were observed in 191 isolates that were examined at both loci. Mixed infections, accounting for 17.8% of cases, were associated with primary PCP. Genotype frequency distribution patterns varied by patients' place of diagnosis but not by place of birth. Genetic variation at the two loci suggests three probable characteristics of transmission: that most cases of PCP do not result from infections acquired early in life, that infections are actively acquired from a relatively common source (humans or the environment), and that humans, while not necessarily involved in direct infection of other humans, are nevertheless important in the transmission cycle of P. carinii f. sp. hominis.

Use of recombinant human soluble TNF receptor in anorectic tumor-bearing rats

With progression of tumor growth, rats demonstrate anorexia and reduced food intake, a function of meal number and meal size. Tumor necrosis factor-alpha (TNF-alpha), a recognized anorectic agent, reacts with two different receptors (type I: 55 kDa; type II: 75 kDa). We used a dimeric, pegylated 55-kDa TNF receptor construct to test its effects on food intake, meal number, and meal size, which were continuously measured with a rat eater meter in 16 Fischer 344 male rats injected with 10(6) viable methylcholanthrene cells. When anorexia developed, rats received a subcutaneous injection of either 0.25 mg/kg body wt of soluble TNF receptor construct (study) or vehicle (tumor-bearing control). Before TNF inhibitor injection, no differences were observed in food intake, meal number, or meal size between the two groups. After the TNF inhibitor injection, study vs. control rats significantly improved food intake as a result of an increase in meal number and meal size. Rats also showed a significant improvement in body weight. These data suggest that TNF-alpha, in addition to other cytokines, contributes to the anorexia of tumor growth, probably mediated via the hypothalamus.

Therapy of relapsing multiple sclerosis. Treatment approaches for nonresponders

There is increasing impetus to begin disease-modifying therapy for relapsing multiple (R-MS) early, before the development of irreversible tissue damage and resultant permanent disability. However, all of the currently-approved therapies for relapsing multiple sclerosis are only partially effective for patients as a group. Treatment failure can be due to noncompliance with therapy, intolerable adverse effects, the development of neutralizing antibodies, or non-responsive disease. Neurologists managing patients on disease-modifying therapy for R-MS must remain vigilant for these issues and take appropriate action when necessary.

Management of impairment, disability, and handicap due to multiple sclerosis

In this article, we update management measures for patients with multiple sclerosis (MS) that can improve or prevent impairment, disability, and handicap and include those factors that a primary-care physician can implement or facilitate. The medical literature since 1989 was reviewed. Although new drug trials hold promise to decrease impairment from MS, well-coordinated interdisciplinary care to minimize disability and handicap most profoundly affect the quality of life for patients with MS. MS is usually not severely disabling, and appropriately timed intervention can prevent secondary impairment and reduce disability and handicap. Pharmacologic, physical, and psychosocial issues--ranging from spasticity, pain, weakness, and tremor to neurogenic bowel management and sexuality--are addressed. General wellness measures remain important. The influence of the Americans With Disabilities Act is discussed, and specific adaptive equipment and social resources are outlined. The ultimate goals of management of patients with MS are functional independence and efficient use of medical and community resources: a focus on "ability" rather than "disability." Although impairment can limit function, wellness and adjustment have no boundaries.

Rational clinical immunotherapy for multiple sclerosis

In this article, we assess the roles and the efficacy of immunopharmacologic agents in the treatment of multiple sclerosis (MS) and other demyelinating disease syndromes. The initial clinical manifestations of demyelinating disease, immunotherapeutic goals, efficacy of individual agents, and specific immunopharmacologic recommendations are discussed. MS and other idiopathic demyelinating disease syndromes can be effectively managed with immunotherapy. Exacerbations are treatable, and the frequency and severity of exacerbations can be reduced. Although some agents have a minor effect on progression of disability, current approaches have not proved to have a major influence on treatment of progressive MS. Immunotherapy for inflammatory demyelinating disease necessitates a high degree of clinical certainty about the diagnosis. Because all available therapeutic agents have limitations and significant toxic effects, careful consideration is necessary before use. Treatment should be individualized on the basis of the clinical course of the disease and the degree of patient disability.

Tubular carcinoma of the breast: an institutional review

Tubular carcinoma of the breast is a rare, but distinct, well-differentiated histologic subtype of invasive carcinoma, known for its favorable prognosis. Review of the literature reveals controversy relative to the frequency of tubular carcinoma, the mammographic appearance, the incidence of lymph node metastases, and the need for axillary node dissection. In consideration of these variables and because of the concern that this type of breast cancer was being surgically over-treated, this review was undertaken. Through the use of our tumor registry, a retrospective review of patients with invasive breast cancer was carried out from January 1984 to September 1995. Of 1483 total cases of invasive breast carcinoma, 22 (1.5%) had a diagnosis of pure tubular carcinoma (> 90% tubular component). The mean age was 58 years (range, 37-80). In 14 patients, the lesion was detected solely by mammography with a mean size of 1.0 cm (range, 0.5-1.5 cm). The mean pathologic tumor size was 1.2 cm (range, 0.5-2.9 cm). The mean number of nodes, in 22 axillary specimens, was 19 (range, 8-30). In one patient, there was lymph node metastasis to a single node (4.5% incidence), which demonstrated tubular characteristics. Presently, 18 of the patients are alive and disease free, with a mean follow-up of 3.5 years (range, 4 months to 9 years). Our study confirms the low incidence of pure tubular carcinoma, 1.5 per cent, with the lesions being small, 1.2 cm in mean size. The mammographic lesions had no unique features that would distinguish tubular from other invasive carcinomas. With the small tumor size and the overall excellent prognosis, these patients are ideal candidates for breast preservation. Most importantly, the review did demonstrate that even in pure tubular breast carcinoma, lymph node metastases, though rare, can occur.

Ventilatory dysfunction in multiple sclerosis

Multiple sclerosis (MS) can produce a variety of different respiratory abnormalities because of the multi-focal nature of central nervous system involvement in the disease. This article reviews the different patterns of respiratory involvement in MS and correlates them with the known neuroanatomy of respiratory control. Methods of monitoring pulmonary function in MS are explored, and the treatment of acute ventilatory failure in MS is discussed.

Tizanidine treatment of spasticity caused by multiple sclerosis: results of a double-blind, placebo-controlled trial. US Tizanidine Study Group

This multicenter, stratified, randomized, placebo-controlled, double-blind trial evaluated tizanidine for use in the United States for spasticity secondary to MS. The 15-week trial was divided into baseline (weeks 0 and 1), titration (2 mg to a maximum of 36 mg/d; weeks 2 to 4), and plateau (weeks 5 to 13) phases, followed by dose tapering (week 14) and a final visit (week 15). Primary efficacy parameters were scores on muscle tone (Ashworth Scale) and type and frequency of muscle spasms (patient diaries). All efficacy parameters were evaluated by the physician/assessor, and the physician/prescriber was responsible for all dosage adjustments. The patient, physician/assessor, and physician/prescriber made global evaluations of antispastic efficacy. Tizanidine produced a significantly greater reduction than placebo in spasms and clonus (patient diaries) but no significant differences in Ashworth scores. Patients and physician/prescribers, but not physician/assessors, gave significantly better scores in the overall assessment of efficacy and tolerability. No significant differences in other secondary efficacy parameters were noted. Adverse events were reported for 66 (61%) of the 109 placebo-treated patients and 101 (91%) of the 111 tizanidine-treated patients; 6 (6%) and 14 (13%) discontinued treatment, respectively. Patient and physician perception of improvement demonstrated more consistent differences between groups than did the Ashworth Scale, perhaps because of inexperience with this measure or failure to consider time between drug administration and assessment.

Pituitary-adrenal axis response to arginine vasopressin in patients with major depression

Arginine vasopressin (AVP) was administered to 21 patients with major depression and 20 normal control subjects. Thirty-two subjects also underwent an overnight dexamethasone suppression test. The patient group did not differ significantly from the control group in adrenocorticotropic hormone (ACTH) or cortisol response. Dexamethasone suppression status did not affect ACTH or cortisol response. This study supports the hypothesis that unlike the response to corticotropin releasing hormone, the ACTH response to AVP is not attenuated in depression.

Visual, somatosensory, olfactory, and gustatory hallucinations

Hallucinations that involve any of the sensory modalities may accompany a number of functional and organic conditions. Although characteristics of the hallucinations are not specific, they are characteristic and suggestive of specific disorders. Appropriate evaluation and treatment require consideration of the past psychiatric, neurologic, and medical history; assessment of accompanying psychiatric and neurologic signs and symptoms; and degree of response to conventional therapy. Any patient with hallucinations of recent onset or presenting a significant change in the nature of prior hallucinations, particularly when the patient does not respond to conventional therapy, deserves an evaluation to rule out treatable organic factors.

Subchronic toxicity study of Caramel Colour II in F344 rats

Caramel Colour II is a distinct type of colourant with a pronounced reddish hue. It is made with sulphite reactants but without ammonia. The red colour and a high alcohol solubility provide functional characteristics that are important in foods or beverages containing natural flavour extractives. Caramel Colour II is widely used in ice creams and liqueurs; however, it represents less than 1% of total caramel colour manufacture. The toxicity of Caramel Colour II was evaluated in a 13-wk study in Fischer-344 (F344) rats. The test material was mixed with demineralized water and the solutions were given to the animals ad lib. in the drinking fluid. The concentrations of caramel colour in the drinking fluid were adjusted periodically to achieve the desired caramel colour intake/kg body weight/day. Groups of 20 rats/sex were given Caramel Colour II at levels of 0, 4, 8, 12 or 16 g/kg for at least 13 wk. There were no deaths in any of the groups fed Caramel Colour II. All rats fed caramel colour had soft faeces. All treated groups also had lower fluid consumption that was attributed to poor palatability of the high concentrations of caramel colour that were fed. A number of changes observed (reduced food consumption in all treatment groups except males given 4 g/kg; significantly lower body weights for males given 12 g/kg or more and for females given 8 g/kg or more; lower urine volume and higher specific gravity) were attributed to the reduced water intake and not considered to be toxicologically significant. There were no consistent treatment-related alterations in haematology or blood chemistry variables, and random changes noted were not associated with macroscopic or microscopic pathological alterations. There were no toxicologically important pathological findings. Based on this study, Caramel Colour II was not toxic in F344 rats treated for 13 wk. The highest dose level tested in this study (16 g/kg) was considered to be the no-observed-adverse-effect level.

Blunted ACTH response to hypoglycemic stress in depressed patients but not in patients with schizophrenia

In this study, 7 hospitalized patients with major depression (MD), 5 hospitalized patients with schizophrenia (S), and 13 control subjects (C) were administered 0.15 units/kg of regular insulin at 1600 h by intravenous bolus infusion. ACTH, cortisol, and glucose levels were measured intermittently for 2h following infusion. Baseline ACTH, cortisol and glucose levels were similar in Cs, MDs, and Ss. The mean glucose nadir was equivalent for Cs, patients with MD, and patients with S. Patients with MD had a blunted ACTH response (F = 3.28; df = 12,126; p = .0004) and cortisol response (F = 4.20; df = 12,132; p = .0001) to hypoglycemia when compared to Cs and patients with S. Carroll Depression Rating Scale scores in patients with S (23 +/- 10) were similar to patients with MD (30 +/- 8) and significantly higher than in controls (1 +/- 2) (F = 55.2; df = 2.22; p = .0001). These findings suggest that patients with MD show different ACTH and cortisol responses to hypoglycemic stress which are not explained by negative feedback of baseline ACTH or cortisol, glucose nadir, or the number of depressive symptoms per se.

Peripheral sensory abnormalities in patients with multiple sclerosis

Although multiple sclerosis primarily affects myelin within the central nervous system, both pathologic and physiological studies suggest that mild deficits in peripheral nervous system myelin may be common. To evaluate this question further, we performed near nerve studies on sural nerves of 14 patients with multiple sclerosis. Peak-to-peak amplitude and maximum conduction velocity were normal in 9 of 14 patients, while minimum conduction velocity, or the velocity of the slowest-conducting component of the sensory action potential, was abnormally reduced in 9 patients. In addition, the supernormal period was evaluated for patients and compared with a control sample; multiple sclerosis patients showed a significant reduction in the amplitude of supernormality. Both the reduction in minimum conduction velocity and the alteration in the supernormal period are consistent with a mild defect in peripheral myelin.

A clinical and biomechanical assessment of the Hall surgical miniplate system

The Hall surgical miniplating system has been evaluated for use in maxillofacial trauma and orthognathic surgery. The biomechanical characteristics of the plates have been examined and experience gained, using 53 plates, in 25 patients is presented. The feature which distinguishes these plates is the narrow bridge between paired screw platforms. The specially designed screwdriver has a splined head which allows screw transfer to be carried out as a one-handed procedure. The plates show considerable advantages over existing small plate systems in their size, malleability and consequent ease of handling.

Immunosuppressive treatment of multiple sclerosis

Multiple sclerosis is thought, by many investigators, to be an immunologic disease. Therefore, a rationale exists for treating this disease by immunosuppressive therapy. In exacerbating-remitting multiple sclerosis, corticosteroids and adrenocorticotropic hormone are the most widely used drugs; high doses of intravenously administered methylprednisolone have recently gained favor. Chronic progressive multiple sclerosis has been treated with a number of immunosuppressive regimens, several of which have shown promise to date. Cyclophosphamide and azathioprine have been used most often and are reviewed in this report, as are other agents currently under investigation. No firm guidelines for the treatment of chronic progressive multiple sclerosis can be offered, but an approach to immunosuppressive therapy is suggested in this review.

Cold-induced peripheral nerve damage: involvement of touch receptors of the foot

A 31-year-old male developed paresthesia and numbness of mainly the right foot following exposure to nonfreezing temperatures under moist conditions over a period of 1 week. The symptoms gradually improved over several months. When seen for electrophysiological studies 6 months after the injury, there was no sensory loss on clinical examination, although he continued to complain of distal numbness of the right foot. The right extensor digitorum brevis muscle was atrophic, and the distal motor latency in the peroneal nerve was prolonged. Conduction studies of the right sural nerve showed a predominantly distal diminution of the SAP evoked by electrical stimulation at the dorsum pedis. Action potentials evoked by tactile stimulation of Pacinian corpuscles showed a prolonged latency on the symptomatic side, suggesting that the most pronounced pathological changes in immersion injury may be localized to the very distal portion of the nerve at the nerve fiber-receptor junction.

Immunosuppression with high-dose i.v. cyclophosphamide and ACTH in progressive multiple sclerosis: cumulative 6-year experience in 164 patients

One hundred sixty-four patients with chronic progressive multiple sclerosis (MS) have been treated with a regimen of high-dose IV cyclophosphamide and ACTH over the past 6 years. Their status was reviewed to determine complications associated with treatment, dosage of medication used to induce a remission, factors which may predict a response to therapy, and subsequent course following treatment. One year following initial treatment, 81% of patients were improved or stabilized. Reprogression occurred in 69% of patients at a mean time of 17.6 months. Fifty-eight patients who initially stabilized after treatment and then reprogressed were treated a second time. One year after retreatment, 70% of these patients were improved or stabilized. Alopecia, nausea and vomiting, and minor infections were the most frequent complications. There were no deaths associated with treatment, the complication rate did not change with multiple treatments, and no late complications have yet been observed. Improvement tended to occur in younger patients with shorter disease duration. Although this treatment regimen is generally well tolerated and can favorably affect the course of chronic progressive MS in a majority of patients, a single treatment does not induce a permanent remission, and some form of maintenance treatment or retreatment is required. Current treatment programs involve testing a modified induction regimen and periodic outpatient booster injections to maintain remission.

Immunosuppression in progressive multiple sclerosis with high dose intravenous cyclophosphamide and monoclonal antibodies

Our work with multiple sclerosis has demonstrated a favorable effect on the course of chronic progressive multiple sclerosis in two-thirds of patients treated with cyclophosphamide/ACTH. However, alternative methods of therapy, or repeated treatments with cyclophosphamide and ACTH are required for longer term control of the illness. We are attempting to assess the efficacy of outpatient maintenance cyclophosphamide, but do not as yet have any data to support the use of this form of treatment. Cyclophosphamide and ACTH can be given to multiple sclerosis patients without significant serious toxicity. Monoclonal antibody therapy of multiple sclerosis is in its beginning stages. The treatment appears to be safe and has produced some interesting data indicating that rapid entry of some labeled lymphocytes into the nervous system can be measured by this technique. Since these are phase one pilot trials designed to assess immune parameters and only small numbers of patients have been treated, no clinical results have been obtained. No adverse effects of monoclonal antibody therapy were observed.

Teicoplanin as a prophylactic antibiotic for dental bacteraemia

The potential of teicoplanin, a new glycopeptide antibiotic, was assessed according to its ability to decrease the occurrence and severity of bacteraemia following dental extraction. Preliminary studies with ten volunteers showed that mean peak serum concentrations of teicoplanin were reached 3 hours after intramuscular administration and were 2.6 mg/l (1.5 mg/kg regimen) and 5.0 mg/l (3 mg/kg regimen). Three groups of ten patients participated in the bacteraemia study. Group one received no prophylaxis whereas groups two and three received 200 mg of teicoplanin intramuscularly, or 3 g amoxycillin orally respectively, 1 h prior to extraction. Sequential blood cultures were inoculated at timed intervals from a single venous blood sample taken 2 min after commencing surgery. Bacteraemia was detectable in all patients who received no prophylaxis whereas those given teicoplanin and amoxycillin had detectable bacteraemia in 6/10 and 4/10 cases, respectively. Teicoplanin was clearly effective in reducing the incidence and degree of post dental extraction bacteraemia although apparently rather less so than amoxycillin. In-vitro tests of susceptibility and bactericidal activity showed that teicoplanin possesses comparable activity to those antibiotics which are either in use or have been used for the suppression of bacteraemia following dental extraction.