Does the NHS Diabetes Prevention Programme prevent diabetes? A population-based matched cohort study

Background

To reduce the incidence of type 2 diabetes (T2DM) in England, the National Health Service piloted the Diabetes Prevention Programme (DPP). The DPP aims to prevent T2DM by providing high-risk adults with access to 13 face-to-face sessions over nine months that focus on diet and weight management. The DPP has been shown to improve intermediate outcomes for T2DM prevention (weight loss and glycated haemoglobin (HbA1c) reduction). However, there is a lack of evidence examining incident T2DM as the outcome.

Methods

We conducted a retrospective observational cohort study using linked electronic health records from primary (Clinical Practice Research Datalink) and secondary (Hospital Episode Statistics) care for June 2016 to January 2019. We compared rates of new T2DM diagnoses among eligible adults who were referred to the DPP with rates for propensity score-matched (ratio of 1:4) controls who were eligible for the DPP but were not invited. DPP eligibility was defined as having HbA1c levels of 42-47 mmol/mol or fasting plasma glucose (FPG) levels of 5.5-6.9 mmol/L. Adults with pre-existing T2DM were excluded. Time to the first record of T2DM was modelled using Cox regression with age, alcohol intake, body mass index, ethnicity, sex, HbA1c, index of multiple deprivation and smoking status included as covariates.

Results

We identified 2205 individuals who participated in the DPP and 8820 matched controls with a similar breakdown in age, sex, HbA1c and FPG. During the 2.5-year study period, 4.13% of DPP individuals developed T2DM vs 6.42% of controls. Our results indicate that DPP referrals were associated with a 59% reduction T2DM incidence rates [adjusted hazard ratio=0.41;95%CI=0.38-0.44].

Conclusions

This is the first study to investigate the impact of the DPP on T2DM, relative to usual care. Our results provide support for the effectiveness of DPP in preventing T2DM onset and are compatible with findings for similar interventions in other settings.

Key messages

The evidence suggests that providing consistent face-to-face sessions which concentrate on diet and weight management can reduce short-term T2DM incidences in high-risk adults. With a 59% reduction in T2DM rates in DPP referees relative to eligible adults who were not referred, the DPP is effective in reducing short-term T2DM incidences in high-risk adults.

Validating loci associated with bovine respiratory disease complex in pre-weaned Holstein calves

Bovine respiratory disease (BRD) is considered one of the most economically important diseases in the cattle industry. Ultimately, the selection of cattle that are less susceptible to disease will allow producers to reduce the prevalence of BRD and lessen its economic impact. The objective of this study was to validate previously identified loci associated with susceptibility to BRD in an independent population of 140 pre-weaned Holstein calves from Wisconsin (WI). Using the McGuirk health scoring system, calves were classified as either clinically affected with BRD (n = 35) or healthy (n = 105). Additive genotypic tests were performed for genomic regions previously associated with susceptibility to BRD in calves from California (CA) and New Mexico (NM). Using this method, 4 loci (P < 0.01) consisting of 10 SNP were validated in the WI population, including 2 loci from CA, 1 locus from NM, and 1 locus from a combined CA + NM population. Most of the positional candidate genes and transcription factor binding site motifs associated with these loci have functions related to innate and adaptive immune responses. The validation of loci associated with susceptibility to BRD in independent populations allows producers to more reliably select cattle that are less susceptible to BRD, improving animal welfare, decreasing the annual revenue losses, and lowering the prevalence of the disease.

Composition and Use of Cannabis Extracts for Childhood Epilepsy in the Australian Community

Recent surveys suggest that many parents are using illicit cannabis extracts in the hope of managing seizures in their children with epilepsy. In the current Australian study we conducted semi-structured interviews with families of children with diverse forms of epilepsy to explore their attitudes towards and experiences with using cannabis extracts. This included current or previous users of cannabis extracts to treat their child's seizures (n = 41 families), and families who had never used (n = 24 families). For those using cannabis, extracts were analysed for cannabinoid content, with specific comparison of samples rated by families as "effective" versus those rated "ineffective". Results showed that children given cannabis extracts tended to have more severe epilepsy historically and had trialled more anticonvulsants than those who had never received cannabis extracts. There was high variability in the cannabinoid content and profile of cannabis extracts rated as "effective", with no clear differences between extracts perceived as "effective" and "ineffective". Contrary to family's expectations, most samples contained low concentrations of cannabidiol, while Δ9-tetrahydrocannabinol was present in nearly every sample. These findings highlight profound variation in the illicit cannabis extracts being currently used in Australia and warrant further investigations into the therapeutic value of cannabinoids in epilepsy.

Statin prescribing for prevention of cardiovascular disease amongst people with severe mental illness: Cohort study in UK primary care

BACKGROUND

Severe mental illness (SMI) is associated with excess cardiovascular disease (CVD) morbidity, but little is known on provision of preventative interventions. We investigated statin initiation for primary CVD prevention in individuals with and without SMI.

METHODS

We used primary care data from The Health Improvement Network from 2006 to 2015 for UK patients aged 30-99years with no pre-existing CVD conditions and selected individuals with schizophrenia (n=13,252) or bipolar disorder (n=11,994). In addition, we identified samples of individuals without schizophrenia (n=66,060) and bipolar disorder (n=59,765), but with similar age and gender distribution. Missing data on CVD covariates were estimated using multiple imputation. Statin prescribing differences between individuals with and without SMI were investigated using multivariable Poisson regression models.

RESULTS

Initiation of statin prescribing was between 2 and 3 fold higher in people aged 30-59years with SMI than in those without after adjusting for CVD covariates. The rates in those aged 60-74years with SMI were similar or slightly higher relative to those without SMI. The incidence rate ratio (IRR) was 1.15 (95% CI 1.03-1.28) for bipolar disorder and 1.00 (0.91-1.11) for schizophrenia. The rate of statin prescribing was lower (IRR 0.81 (0.66-0.98)) amongst the oldest (aged 75+years) with schizophrenia relative to those without schizophrenia.

CONCLUSIONS

Despite higher rates of new statin prescriptions to younger individuals with SMI relative to individuals without SMI, there was evidence of lower rates of statin initiation for older individuals with schizophrenia, and this group may benefit from additional measures to prevent CVD.

Statin prescribing for people with severe mental illnesses: a staggered cohort study of 'real-world' impacts

OBJECTIVES

To estimate the 'real-world effectiveness of statins for primary prevention of cardiovascular disease (CVD) and for lipid modification in people with severe mental illnesses (SMI), including schizophrenia and bipolar disorder.

DESIGN

Series of staggered cohorts. We estimated the effect of statin prescribing on CVD outcomes using a multivariable Poisson regression model or linear regression for cholesterol outcomes.

SETTING

587 general practice (GP) surgeries across the UK reporting data to The Health Improvement Network.

PARTICIPANTS

All permanently registered GP patients aged 40-84 years between 2002 and 2012 who had a diagnosis of SMI. Exclusion criteria were pre-existing CVD, statin-contraindicating conditions or a statin prescription within the 24 months prior to the study start.

EXPOSURE

One or more statin prescriptions during a 24-month 'baseline' period (vs no statin prescription during the same period).

MAIN OUTCOME MEASURES

The primary outcome was combined first myocardial infarction and stroke. All-cause mortality and total cholesterol concentration were secondary outcomes.

RESULTS

We identified 2944 statin users and 42 886 statin non-users across the staggered cohorts. Statin prescribing was not associated with significant reduction in CVD events (incident rate ratio 0.89; 95% CI 0.68 to 1.15) or all-cause mortality (0.89; 95% CI 0.78 to 1.02). Statin prescribing was, however, associated with statistically significant reductions in total cholesterol of 1.2 mmol/L (95% CI 1.1 to 1.3) for up to 2 years after adjusting for differences in baseline characteristics. On average, total cholesterol decreased from 6.3 to 4.6 in statin users and 5.4 to 5.3 mmol/L in non-users.

CONCLUSIONS

We found that statin prescribing to people with SMI in UK primary care was effective for lipid modification but not CVD events. The latter finding may reflect insufficient power to detect a smaller effect size than that observed in randomised controlled trials of statins in people without SMI.

Management Training and Networking in Small and Medium-Sized Enterprises in Three European Regions: Implications for Business Support

The authors aim to develop a better understanding of small-business owners' attitudes towards, and experiences of, management training through a study of small mechanical engineering firms and key support providers in three European regions: Stuttgart (Germany), Aarhus (Denmark), and South London (England). Important differences between the three regions in support networks are highlighted. The limited networking between small-business owners and training providers in South London is explained by a lack of embeddedness of UK small engineering firms in the institutional framework supporting business. The absence of a critical mass of engineering businesses, the limited experiences of business owners and the weak business-support network in South London are mutually reinforcing and perpetuate the isolation of small and medium-sized enterprises (SMEs) from external training providers. Drawing on experience in Stuttgart and Aarhus, some policy proposals are offered which are aimed at increasing the take-up of management training by UK SMEs.

Effectiveness and cost-effectiveness of a cardiovascular risk prediction algorithm for people with severe mental illness

Introduction

Cardiovascular risk prediction tools are important for cardiovascular disease (CVD) prevention, however, which algorithms are appropriate for people with severe mental illness (SMI) is unclear.

Objectives/aims

To determine the cost-effectiveness using the net monetary benefit (NMB) approach of two bespoke SMI-specific risk algorithms compared to standard risk algorithms for primary CVD prevention in those with SMI, from an NHS perspective.

Methods

A microsimulation model was populated with 1000 individuals with SMI from The Health Improvement Network Database, aged 30–74 years without CVD. Four cardiovascular risk algorithms were assessed; (1) general population lipid, (2) general population BMI, (3) SMI-specific lipid and (4) SMI-specific BMI, compared against no algorithm. At baseline, each cardiovascular risk algorithm was applied and those high-risk (> 10%) were assumed to be prescribed statin therapy, others received usual care. Individuals entered the model in a ‘healthy’ free of CVD health state and with each year could retain their current health state, have cardiovascular events (non-fatal/fatal) or die from other causes according to transition probabilities.

Results

The SMI-specific BMI and general population lipid algorithms had the highest NMB of the four algorithms resulting in 12 additional QALYs and a cost saving of approximately £37,000 (US$ 58,000) per 1000 patients with SMI over 10 years.

Conclusions

The general population lipid and SMI-specific BMI algorithms performed equally well. The ease and acceptability of use of a SMI-specific BMI algorithm (blood tests not required) makes it an attractive algorithm to implement in clinical settings.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Music therapy for service users with dementia: a critical review of the literature

Dementia is an organic mental health problem that has been estimated to affect over 23 million people worldwide. With increasing life expectancy in most countries, it has been estimated that the prevalence of dementia will continue to significantly increase in the next two decades. Dementia leads to cognitive impairments most notably short-term memory loss and impairments in functioning and quality of life (QOL). National policy in the UK advocates the importance of early diagnosis, treatment and social inclusion in maintaining a good QOL. First-line treatment options often involve drug therapies aimed at slowing down the progression of the illness and antipsychotic medication to address challenging behaviours. To date, research into non-pharmacological interventions has been limited. In this manuscript, we review the literature that has reported evaluations of the effects of music therapy, a non-pharmacological intervention. The results of six studies reviewed suggest that music therapy may have potential benefits in reducing anxiety, depression and agitated behaviour displayed by elderly people with dementia as well as improving cognitive functioning and QOL. Furthermore, music therapy is a safe and low-cost intervention that could potentially be offered by mental health nurses and other carers working in residential settings.

Enhanced surveillance of methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia in children in the UK and Ireland

OBJECTIVE

To determine the incidence and demographic features of methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia in children in the UK and Ireland and to characterise MRSA isolated from cases.

DESIGN

Prospective surveillance study.

SETTING

Children aged <16 years hospitalised with bacteraemia due to MRSA.

METHODS

Cases were ascertained by active surveillance involving paediatricians reporting to the British Paediatric Surveillance Unit and by routine laboratory surveillance. Patient characteristics were obtained using questionnaires sent to reporting paediatricians. MRSA isolates were characterised using molecular and phenotypic techniques including antimicrobial susceptibility testing.

RESULTS

265 episodes of MRSA bacteraemia were ascertained, involving 252 children. The overall incidence rate was 1.1 per 100 000 child population per year (95% CI 0.9 to 1.2): 61% of the children were aged <1 year (a rate of 9.7 cases per 100 000 population per year (95% CI 8.2 to 11.4)) and 35% were <1 month. Clinical data were obtained from 115 cases. The clinical presentation varied, with fever present in only 16% of neonates compared with 72% of older children. A history of invasive procedure was common, with 32% having had intravascular lines and 13% having undergone surgery. 62% of patients for whom data were available were receiving high-dependency care (46% in SCBU/NICU and 16% in PICU). Of 93 MRSA isolates studied, 73% belonged to epidemic strains widely associated with nosocomial infection in the UK and Ireland.

CONCLUSIONS

MRSA bacteraemia in children was relatively uncommon and was predominantly seen in very young children, often those receiving neonatal or paediatric intensive care. Bacteraemia predominantly involved well-documented epidemic strains of MRSA associated with nosocomial infection.

Elevated C-reactive protein constitutes an independent predictor of advanced carotid plaques in dyslipidemic subjects

Inflammation plays a key role in the physiopathology of atherosclerosis. C-reactive protein (CRP) has been found to predict cardiac events in healthy subjects and in patients with coronary heart disease. However, the relationship between CRP and subclinical atherosclerosis is not well established. We examined the potential relationship between CRP and common carotid artery intima-media thickness and carotid plaques in dyslipidemic subjects. Dyslipidemic patients (n=1051) were recruited for the study. All patients had a complete clinical examination and systematically underwent ultrasonographic evaluation of the extracranial carotid arteries on a duplex system. The serum concentration of CRP was measured by using a sensitive immunoradiometric assay. In a univariate model, a strong positive relationship was found between CRP and the severity of carotid stenosis (P<0.0001). In multivariate analysis, the association between CRP and the degree of carotid atherosclerosis remained significant for advanced plaques (P=0.0007) in male subjects only. Significant correlations were found between CRP and body mass index (P<0.0001) and between CRP and other markers associated with the metabolic syndrome. In this large dyslipidemic population, elevated CRP is an independent predictor of advanced carotid plaques in male subjects. Body mass index and other markers of the metabolic syndrome (HDL cholesterol, triglycerides, diabetes, and high blood pressure) are significant determinants of CRP levels in this population.

Radon-222 and related activities in surface waters of the English Lake District

Activities of radon-222 in selected surface waters of the English Lake District have been determined. Very wide variations were observed. The activity present in lakes and streams depends on the nature of the bedrock or sediment, the presence of faulting, the degree of turbulence, and the supply of fresh water from tributaries and ground waters. Radium-226 and uranium-238 activities were found to be comparable but in no case was it found that radon-222 is significantly supported by dissolved radium-226.

Empirical clusters of DSM-III personality disorders in violent offenders

Violent male offenders in a maximum security hospital and special units in prisons (N = 164) were interviewed with the Structured Clinical Interview for DSM-III Axis II disorders (SCID-II). Cluster analysis of the personality disorder criteria sets identified six diagnostic patterns: (1) antisocial-narcissistic; (2) paranoid-antisocial; (3) borderline-antisocial-passive-aggressive; (4) borderline; (5) compulsive-borderline; and (6) schizoid. Offenders in the first three groups had more extensive criminal careers, and most were identified as psychopaths by the Psychopathy Checklist-Revised (PCL-R). These Groups also had more frequent lifetime histories of substance abuse. A history of affective and anxiety disorders was more common in Groups 3 and 5, and almost two thirds of Group 2 had a history of psychotic disorder. The results emphasize that dangerous offenders are heterogeneous in personality pathology. They also suggest that personality disorder among violent offenders is more commonly represented by recurring patterns of covarying traits than by single categorical entities proposed in the DSM classification.

Relationship of personality disorders to observer ratings of interpersonal style in forensic psychiatric patients

Interpersonal theorists have conceptualised personality disorders as extreme styles defined by the interpersonal circle. Tests of this proposition have previously relied on self-report measures of interpersonal style. This study examined the relationships between observer ratings of interpersonal style (Chart of Interpersonal Reactions in Closed Living Environment [CIR-CLE]) and the personality disorder scales of the Millon Clinical Multiaxial Inventory (MCMI-I) in a sample of male forensic psychiatric inpatients (N = 104). Statistically significant interpersonal components were found for most personality disorder scales, but relationships were generally modest. The results are consistent with the view that the interpersonal circle provides a partial classification of personality disorders.

Production, purification, and characterization of recombinant human hemoglobin rainier expressed in Saccharomyces cerevisiae

Hemoglobin Rainier is a naturally occurring hemoglobin variant in which the beta 145 tyrosine is substituted with cysteine. The alpha and beta Rainier globin cDNAs were cloned in a high copy number vector and expressed in Saccharomyces cerevisiae under the control of galactose-regulated hybrid promoters. Using this system, we have expressed individual alpha and beta Rainier globin chains. Coexpression of both alpha and beta Rainier cDNAs resulted in the production of a functional hemoglobin molecule. Purification of the recombinant protein was accomplished by ion exchange chromatography. The N-termini of the alpha and beta chains were correctly processed, and the molecular mass, as determined by mass spectrometry, indicated amino acid composition identical to that of natural hemoglobin Rainier. The chromatographic properties of the recombinant hemoglobin Rainier were similar to human-derived hemoglobin A0. The purified recombinant hemoglobin molecule was shown to have an elevated oxygen affinity and a reduced cooperativity as previously reported for natural hemoglobin Rainier. Production of recombinant hemoglobin and especially hemoglobin variants like hemoglobin Rainier has the potential to facilitate use of hemoglobin as a blood substitute as well as in specific applications, such as for use as a therapeutic agent in the treatment of hypotension associated with septic shock.

Brucella abortus conjugated with a peptide derived from the V3 loop of human immunodeficiency virus (HIV) type 1 induces HIV-specific cytotoxic T-cell responses in normal and in CD4+ cell-depleted BALB/c mice

We have previously shown that immunization of mice with human immunodeficiency virus (HIV)-derived proteins or peptides conjugated to inactivated Brucella abortus induces the secretion of virus-neutralizing antibodies, predominantly of the immunoglobulin G2a (IgG2a) isotype. In addition, B. abortus activates human CD4+ and CD8+ cells to secrete gamma interferon. Since these are both characteristics of a Th1-type immune response, which is associated with the development of cell-mediated immunity, it was important to determine if B. abortus conjugates would also act as a carrier to induce a cytotoxic T-lymphocyte (CTL) response. To test this hypothesis, we conjugated an 18-amino-acid peptide from the V3 loop of the MN strain of HIV-1 gp120 that contains both B- and cytotoxic T-cell epitopes to B. abortus (B. abortus-MN 18-mer). A 10-amino-acid fragment of this peptide has been shown to be the minimal CTL determinant presented by murine H-2Dd. It was found that two in vivo immunizations with 10(8) organisms of B. abortus-MN 18-mer followed by in vitro stimulation with peptide induced a virus-specific CTL response. Conjugation to B. abortus was required for in vivo priming, since there was no induction of memory CTLs when B. abortus was only mixed with peptide. Targets pulsed with peptide as well as those infected with a vaccinia virus encoding HIV gp160 were killed, demonstrating recognition of naturally processed envelope. Also, major histocompatibility complex-incompatible L cells which were infected with vaccinia viruses that encoded H-2Dd, but not H-2Kd, and pulsed with peptide were lysed. This demonstrated the appropriate major histocompatibility complex class I restriction. Treatment of the mice with anti-L3T4 prior to immunization caused a severe depletion of CD4+ lymphocytes, yet it did not decrease the CTL priming. Thus, inactivated B. abortus can induce non-CD4+ cells to produce the cytokines required for CTL induction. We conclude that B. abortus stimulates a cellular as well as a humoral immune response, even in the relative absence of CD4+ helper cells. It may be a particularly useful vaccine carrier in HIV-1-infected individuals or others with impaired CD4+ T-cell function.

Thermal response in murine L929 cells lacking alpha B-crystallin expression and alpha B-crystallin expressing L929 transfectants

We investigated the role of alpha B-crystallin expression in the development of thermotolerance in murine L929 cells. An initial heat-shock of 10 min at 45 degrees C induced thermotolerance in these cells to a heat challenge at 45 degrees C administered 24 h later. The thermotolerance ratio at 10(-1) isosurvival was 1.7. Expression of alpha B-crystallin gene was not detected during the 24 h incubation at 37 degrees C following heat shock by either northern or western blots. In contrast, inducible HSP70 synthesis was observed during this time period. Thus, this cell line provided an unique system in which to examine the effects of transfected alpha B-crystallin on thermoresistance and thermotolerance. Cells stably transfected with alpha B-crystallin under the control of an inducible promoter did not show a significant increase in the ability to develop thermotolerance. However, a stably transfected L929 clone expressing high levels of constitutive alpha B-crystallin exhibited an approximately 50% increase in thermal resistance over parental and control cells. Though expression of alpha B-crystallin is not requisite for the development of thermotolerance in L929 cells, overexpression of transfected alpha B-crystallin can contribute to increased thermoresistance.

Application of Cerenkov radiation for the assay of 226Ra in natural water

A Cerenkov based method has been developed for the determination of 226Ra via its beta-emitting daughters, 214Bi and 214Pb. Radium isotopes are separated from interfering elements by coprecipitation on barium sulphate. The precipitate is dissolved in an alkaline solution of EDTA and the Cerenkov signal produced by the build-up of daughter beta activities is counted after 25 days using the tritium channel of a liquid scintillation counter. To correct for any contribution from the daughters of the radium isotopes 224Ra and 228Ra present in the sample, the barium(radium) sulphate is reprecipitated, dissolved in EDTA, and counted 2 days later. Using this procedure, 228Ra can be determined in the same sample. Cerenkov counting efficiency was found to be 77.25%. A lower limit of detection of 17.4 mBq l-1 (based on 3 sigma of the background with 500 min counting time) was achieved. Any liquid scintillation counter can be used. Chemical recoveries in the range 75-95% were determined gravimetrically. Data from both artificial spiked samples and natural samples are presented.

Brucella abortus conjugated with a gp120 or V3 loop peptide derived from human immunodeficiency virus (HIV) type 1 induces neutralizing anti-HIV antibodies, and the V3-B. abortus conjugate is effective even after CD4+ T-cell depletion

Human immunodeficiency virus type 1 (HIV-1) infection is associated with loss of function and numbers of CD4+ T-helper cells. In order to bypass the requirement for CD4+ cells in antibody responses, we have utilized heat-inactivated Brucella abortus as a carrier. In this study we coupled a 14-mer V3 loop peptide (V3), which is homologous to 9 of 11 amino acids from the V3 loop of HIV-1 MN, and gp120 from HIV-1 SF2 to B. abortus [gp120(SF2)-B. abortus]. Our results showed that specific antibody responses, dominated by immunoglobulin G2a in BALB/c mice, were induced by these conjugates. Sera from the immunized mice bound native gp120 expressed on the surfaces of cells infected with a recombinant vaccinia virus gp160 vector (VPE16). Sera from mice immunized with gp120(SF2)-B. abortus inhibited binding of soluble CD4 to gp120, whereas sera from mice immunized with V3-B. abortus were ineffective. Sera from mice immunized with either conjugate were capable of blocking syncytium formation between CD4+ CEM cells and H9 cells chronically infected with the homologous virus. Sera from mice immunized with gp120(SF2)-B. abortus were more potent than sera from mice immunized with V3-B. abortus in inhibiting syncytia from heterologous HIV-1 laboratory strains. Importantly, in primary and secondary responses, V3-B. abortus evoked anti-HIV MN antibodies in mice depleted of CD4+ cells, and sera from these mice were able to inhibit syncytia. These findings indicate that B. abortus can provide carrier function for peptides and proteins from HIV-1 and suggest that they could be used for immunization of individuals with compromised CD4+ T-cell function.

Chemically selected subclones of the CEM cell line demonstrate resistance to HIV-1 infection resulting from a selective loss of NF-kappa B DNA binding proteins

To delineate cellular genes that are required for optimal HIV-1 infection, CEM cells were subjected to treatment with the chemical mutagen ethylmethanesulfonate (EMS) and subclones were selected based on their increased resistance to HIV-1 infection and reduced syncytium formation, despite relatively normal CD4 expression (20,000 to 25,000 receptors/cell). Two subclones with this phenotype demonstrated a diminished capacity of HIV-1 long terminal repeat-chloramphenicol acetyl transferase expression either after treatment with the protein kinase C activator PMA, or through Tat-mediated transactivation. In this study, we show that the cellular levels of the NF-kappa B DNA binding proteins (but not AP1 or SP1) are markedly reduced in these cell mutants both at the mRNA and protein levels, resulting in reduced nuclear localization of p50/p65 after PMA induction or treatment with the lymphokine TNF-alpha. Transient reconstitution with a plasmid expressing p50 resulted in partial recovery of PMA-inducible LTR-chloramphenicol acetyl transferase expression. These data suggest that, at least in the CEM T cell line, a selective reduction in the NF-kappa B DNA binding proteins is sufficient to curtail HIV-1 infection.

Chemically selected subclones of the CEM cell line demonstrate resistance to HIV-1 infection resulting from a selective loss of NF-kappa B DNA binding proteins

To delineate cellular genes that are required for optimal HIV-1 infection, CEM cells were subjected to treatment with the chemical mutagen ethylmethanesulfonate (EMS) and subclones were selected based on their increased resistance to HIV-1 infection and reduced syncytium formation, despite relatively normal CD4 expression (20,000 to 25,000 receptors/cell). Two subclones with this phenotype demonstrated a diminished capacity of HIV-1 long terminal repeat-chloramphenicol acetyl transferase expression either after treatment with the protein kinase C activator PMA, or through Tat-mediated transactivation. In this study, we show that the cellular levels of the NF-kappa B DNA binding proteins (but not AP1 or SP1) are markedly reduced in these cell mutants both at the mRNA and protein levels, resulting in reduced nuclear localization of p50/p65 after PMA induction or treatment with the lymphokine TNF-alpha. Transient reconstitution with a plasmid expressing p50 resulted in partial recovery of PMA-inducible LTR-chloramphenicol acetyl transferase expression. These data suggest that, at least in the CEM T cell line, a selective reduction in the NF-kappa B DNA binding proteins is sufficient to curtail HIV-1 infection.

Fusion of human B cell lines with HIV-1 envelope-expressing T cells is enhanced by antigen-specific Ig receptors. Possible mechanism for elimination of gp120-specific B cells in vivo

The possible contribution of Ag-specific Ig receptors on B cells to syncytium formation with HIV-1 envelope (env)-expressing cells was examined. A unique model system was designed that used anti-TNP/TNP interactions between a panel of TNP-specific human B cell lines and TNP-haptenated HIV-1 env-expressing T cells. The prototype B cell line 1:13 (CD4dull) produced few syncytia with vaccinia gp120/41-infected CD4- T cell effectors. However, TNP-haptenation of the HIV-1 env-expressing cells resulted in a five- to 10-fold increase in syncytium formation. The "enhanced" syncytia were blocked by OKT4A mAb, soluble CD4, anti-TNP serum, and TNP-BSA, suggesting a role for both CD4 and Ig receptors. In contrast, the number of syncytia formed between CD4+ CEM T cells and TNP-haptenated effectors was reduced by 30 to 40%, compared with the unhaptenated effectors, suggesting that a fraction of the TNP haptens bound close to the CD4 binding regions on the gp120 envelope, which was confirmed by other experiments. The possibility that B cells specific for the CD4 binding site on HIV-1 gp120 may be involved in syncytium formation with HIV-1 env-expressing cells was tested by screening a panel of five hybrid B cell lines from HIV-1-seropositive individuals. One of these lines produced anti-gp120 antibodies, which bound near the CD4 binding site, and also formed syncytia with HIV-1 env-expressing cells. This study suggests that, in addition to CD4 receptors, certain B cell Ig receptors that bind to gp120 may induce conformational changes leading to cell fusion and their elimination.

Fusion of human B cell lines with HIV-1 envelope-expressing T cells is enhanced by antigen-specific Ig receptors. Possible mechanism for elimination of gp120-specific B cells in vivo

The possible contribution of Ag-specific Ig receptors on B cells to syncytium formation with HIV-1 envelope (env)-expressing cells was examined. A unique model system was designed that used anti-TNP/TNP interactions between a panel of TNP-specific human B cell lines and TNP-haptenated HIV-1 env-expressing T cells. The prototype B cell line 1:13 (CD4dull) produced few syncytia with vaccinia gp120/41-infected CD4- T cell effectors. However, TNP-haptenation of the HIV-1 env-expressing cells resulted in a five- to 10-fold increase in syncytium formation. The "enhanced" syncytia were blocked by OKT4A mAb, soluble CD4, anti-TNP serum, and TNP-BSA, suggesting a role for both CD4 and Ig receptors. In contrast, the number of syncytia formed between CD4+ CEM T cells and TNP-haptenated effectors was reduced by 30 to 40%, compared with the unhaptenated effectors, suggesting that a fraction of the TNP haptens bound close to the CD4 binding regions on the gp120 envelope, which was confirmed by other experiments. The possibility that B cells specific for the CD4 binding site on HIV-1 gp120 may be involved in syncytium formation with HIV-1 env-expressing cells was tested by screening a panel of five hybrid B cell lines from HIV-1-seropositive individuals. One of these lines produced anti-gp120 antibodies, which bound near the CD4 binding site, and also formed syncytia with HIV-1 env-expressing cells. This study suggests that, in addition to CD4 receptors, certain B cell Ig receptors that bind to gp120 may induce conformational changes leading to cell fusion and their elimination.

Phase II study of didemnin B in advanced colorectal cancer

Didemnin B is a depsipeptide derived from a Caribbean tunicate (sea squirt) that has demonstrated antineoplastic activity against a variety of murine tumor models, including the L1210 and P388 leukemia, the B16 melanoma, and M5076 sarcoma cell lines. Based on these data, we designed a phase II trial in which 15 patients with measurable, unresectable colorectal cancer were treated with Didemnin B at an initial dosage of 3.47 mg/m2 over 30 minutes administered by intravenous infusion every 28 days; the dosage was altered in accordance with the toxicity observed, with only one patient requiring a dosage reduction for pronounced nausea and vomiting. No hematologic or nonhematologic toxicity developed. No complete or partial responses were observed. These results do not compare favorably with results of treatments using other single agents or combinations that are currently available for the treatment of advanced colorectal cancers. However, because of the tolerable levels of toxicity experienced by in our patients, it is possible that an insufficient dose of the medication was delivered. We concluded that Didemnin B is not active against of colorectal cancers at the dosage and schedule at which it was administered in this study.

Reduced susceptibility to HIV-1 infection of ethyl-methanesulfonate-treated CEM subclones correlates with a blockade in their protein kinase C signaling pathway

We have described the isolation of chemically induced CEM subclones that express CD4 receptors and bind soluble gp120, yet show a markedly reduced susceptibility to infection with HIV-1. Two subclones were found to have an abnormal response to the protein kinase C (PKC) activator PMA. PMA treatment induced CD3 and CD25 (IL-2R) receptors on the parental line and on other ethyl-methanesulfonate-derived subclones, but not on these two mutants. Direct assays of PKC activity were conducted. Total cellular PKC enzymatic activity was found to be normal in these subclones. PMA-induced CD4 down-modulation occurred normally. In addition, activation of c-raf kinase was normal. Since HIV-1 long terminal repeat contains two functional nuclear factor kB (NF-kB) regulatory elements, we studied the ability of PMA to induce NF-kB binding activity by different assays. Chloramphenicol acetyl transferase (CAT) assays using the HIV-1 (-139)long terminal repeat-CAT construct showed no PMA induction of CAT activity in these subclones (unlike the parental line and other subclones). Okadaic acid, an inhibitor of phosphatases 1 and 2A, did not overcome the defect in these subclones. Gel retardation assays, using a 32P-probe containing the HIV-1 NF-kB probe and nuclear extracts from PMA-treated cells, showed significantly reduced induction of nuclear NF-kB binding proteins in these two subclones compared with wild type CEM and a control subclone. Deoxycholate treatment of cytoplasmic extracts from these subclones released much reduced NF-kB binding proteins from their cytoplasmic pools. Thus, reduced levels of PKC-induced nuclear NF-kB activity in two T cell subclones did not affect their normal cell growth, but correlated with a pronounced reduction in their susceptibility to HIV-1 infection.

Reduced susceptibility to HIV-1 infection of ethyl-methanesulfonate-treated CEM subclones correlates with a blockade in their protein kinase C signaling pathway

We have described the isolation of chemically induced CEM subclones that express CD4 receptors and bind soluble gp120, yet show a markedly reduced susceptibility to infection with HIV-1. Two subclones were found to have an abnormal response to the protein kinase C (PKC) activator PMA. PMA treatment induced CD3 and CD25 (IL-2R) receptors on the parental line and on other ethyl-methanesulfonate-derived subclones, but not on these two mutants. Direct assays of PKC activity were conducted. Total cellular PKC enzymatic activity was found to be normal in these subclones. PMA-induced CD4 down-modulation occurred normally. In addition, activation of c-raf kinase was normal. Since HIV-1 long terminal repeat contains two functional nuclear factor kB (NF-kB) regulatory elements, we studied the ability of PMA to induce NF-kB binding activity by different assays. Chloramphenicol acetyl transferase (CAT) assays using the HIV-1 (-139)long terminal repeat-CAT construct showed no PMA induction of CAT activity in these subclones (unlike the parental line and other subclones). Okadaic acid, an inhibitor of phosphatases 1 and 2A, did not overcome the defect in these subclones. Gel retardation assays, using a 32P-probe containing the HIV-1 NF-kB probe and nuclear extracts from PMA-treated cells, showed significantly reduced induction of nuclear NF-kB binding proteins in these two subclones compared with wild type CEM and a control subclone. Deoxycholate treatment of cytoplasmic extracts from these subclones released much reduced NF-kB binding proteins from their cytoplasmic pools. Thus, reduced levels of PKC-induced nuclear NF-kB activity in two T cell subclones did not affect their normal cell growth, but correlated with a pronounced reduction in their susceptibility to HIV-1 infection.