DepoFoam technology: a vehicle for controlled delivery of protein and peptide drugs

A major challenge in the development of sustained-release formulations for protein and peptide drugs is to achieve high drug loading sufficient for prolonged therapeutic effect coupled with a high recovery of the protein/peptide. This challenge has been successfully met in the formulation of several peptide and protein drugs using the DepoFoam, multivesicular lipid-based drug delivery system. DepoFoam technology consists of novel multivesicular liposomes characterized by their unique structure of multiple non-concentric aqueous chambers surrounded by a network of lipid membranes. The objective of this paper is to demonstrate that DepoFoam technology can be used to develop sustained-release formulations of therapeutic proteins and peptides with high loading. DepoFoam formulations of a protein such as insulin, and peptides such as leuprolide, enkephalin and octreotide have been developed and characterized. The data show that these formulations have high drug loading, high encapsulation efficiency, low content of free drug in the suspension, little chemical change in the drug caused by the formulation process, narrow particle size distribution, and spherical particle morphology. Drug release assays conducted in vitro in biological suspending media such as human plasma indicate that these formulations provide sustained release of encapsulated drug over a period from a few days to several weeks, and that the rate of release can be modulated. In vivo pharmacodynamic studies in rats also show a sustained therapeutic effect over a prolonged period. These results demonstrate that the DepoFoam system is capable of efficiently encapsulating therapeutic proteins and peptides and effectively providing controlled delivery of these biologically active macromolecules.

Persistence of episomal HIV-1 infection intermediates in patients on highly active anti-retroviral therapy

Treatment of HIV-1-infected individuals with a combination of anti-retroviral agents results in sustained suppression of HIV-1 replication, as evidenced by a reduction in plasma viral RNA to levels below the limit of detection of available assays. However, even in patients whose plasma viral RNA levels have been suppressed to below detectable levels for up to 30 months, replication-competent virus can routinely be recovered from patient peripheral blood mononuclear cells and from semen. A reservoir of latently infected cells established early in infection may be involved in the maintenance of viral persistence despite highly active anti-retroviral therapy. However, whether virus replication persists in such patients is unknown. HIV-1 cDNA episomes are labile products of virus infection and indicative of recent infection events. Using episome-specific PCR, we demonstrate here ongoing virus replication in a large percentage of infected individuals on highly active anti-retroviral therapy, despite sustained undetectable levels of plasma viral RNA. The presence of a reservoir of 'covert' virus replication in patients on highly active anti-retroviral therapy has important implications for the clinical management of HIV-1-infected individuals and for the development of virus eradication strategies.

A novel nuclear export activity in HIV-1 matrix protein required for viral replication

An important aspect of the pathophysiology of human immunodeficiency virus type-1 (HIV-1) infection is the ability of the virus to replicate in non-dividing cells. HIV-1 matrix (MA), the amino-terminal domain of the Pr55 gag polyprotein (Pr55), bears a nuclear localization signal that promotes localization of the viral preintegration complex to the nucleus of non-dividing cells following virus entry. However, late during infection, MA, as part of Pr55, directs unspliced viral RNA to the plasma membrane, the site of virus assembly. How MA can mediate these two opposing targeting functions is not understood. Here we demonstrate that MA has a previously undescribed nuclear export activity. Although MA lacks the canonical leucine-rich nuclear export signal, nuclear export is mediated through the conserved Crm1p pathway and functions in both mammalian cells and yeast. A mutation that disrupts the MA nuclear export signal (MA-M4) mislocalizes Pr55 and genomic viral RNA to the nucleus, thereby severely impairing viral replication. Furthermore, we show that MA-M4 can act in a dominant-negative fashion to mislocalize genomic viral RNA even in the presence of wild-type MA. We conclude that the MA nuclear export signal is required to counteract the MA nuclear localization signal, thus ensuring the cytoplasmic availability of the components required for virion assembly.

Predictors of outcome among patients with class II division 1 malocclusion treated with fixed appliances in the permanent dentition

This retrospective study investigated the outcomes achieved in 212 consecutively completed patients with Class II Division 1 malocclusion (overjet > 6 mm). All patients were treated in the permanent dentition with upper and lower fixed appliances. A composite outcome measure was used to identify those cases with an excellent outcome (posttreatment PAR </= 5, posttreatment upper incisor to maxillary plane angle between 104.7 degrees and 115.3 degrees, and anterior movement of the lower incisors </= 2 mm). Logistic regression analysis with patient group as the dependent variable was used to evaluate the predictive value of 32 patient and treatment variables. The three outcome measures (posttreatment PAR score, posttreatment upper incisor inclination, and anterior movement of lower incisors) were ranked and combined to form a single continuous outcome variable. This was used as the dependent variable to carry out further analysis with the linear regression method. Both methods of analysis identified pretreatment overjet and pretreatment upper incisor inclination as significant predictors of outcome. The results revealed that in patients with large overjets an excellent outcome can only be predicted if the upper incisors are very proclined. Every 2 mm increase in overjet (above 4 mm) required approximately a 5 degrees increase in incisor proclination to achieve an excellent outcome.

Variation in periodontal referral in 2 regions in the UK

This study investigated the periodontal referral patterns of general dental practitioners (GDPs) in Northern Ireland (NI) and North West England (NWE). A questionnaire dealing with periodontal referral was sent to all 520 GDPs registered in NI and to 274 GDPs in NWE. A usable return was made by 355 (68%) in NI and 189 (70%) in NWE. The NI dentists made significantly more periodontal referrals (median 5, range 0-80) in the year preceding the survey than those in NWE (median 2, range 0-50), p<0.001. Distance was the only factor significantly related to the referral rate in both regions with those who practised more than 25 miles from a specialist referring significantly fewer patients in both regions. In NI, there was a trend towards increased periodontal referral by GDPs who had attended more postgraduate courses; however, in NWE, this was not the case. The GDPs in NWE were significantly less likely than those in NI to refer patients with medical conditions. It is concluded that there is considerable variation in periodontal referral both within and between the 2 regions studied. It is further concluded that in many cases, non-disease factors, such as the accessibility of the specialist service, have powerful effects on the decisions made by dentists and patients in these regions (NI and NWE) in relation to periodontal referral. Much of the variance in referral in North West England, as in Northern Ireland, remains unexplained.

HIV-1 Nef mediates lymphocyte chemotaxis and activation by infected macrophages

Infection of macrophage lineage cells is a feature of primate lentivirus replication, and several properties of primate lentiviruses seem to have evolved to promote the infection of macrophages. Here we demonstrate that the accessory gene product Nef induces the production of two CC-chemokines, macrophage inflammatory proteins 1alpha and 1beta, by HIV-1-infected macrophages. Adenovirus-mediated expression of Nef in primary macrophages was sufficient for chemokine induction. Supernatants from Nef-expressing macrophages induced both the chemotaxis and activation of resting T lymphocytes, permitting productive HIV-1 infection. These results indicate a role for Nef in lymphocyte recruitment and activation at sites of virus replication.

Classification of the myoelectric signal using time-frequency based representations

An accurate and computationally efficient means of classifying surface myoelectric signal patterns has been the subject of considerable research effort in recent years. Effective feature extraction is crucial to reliable classification and, in the quest to improve the accuracy of transient myoelectric signal pattern classification, an ensemble of time-frequency based representations are proposed. It is shown that feature sets based upon the short-time Fourier transform, the wavelet transform, and the wavelet packet transform provide an effective representation for classification, provided that they are subject to an appropriate form of dimensionality reduction.

Immune activation and virologic response to immunization in recent HIV type 1 seroconverters

Antigenic stimulation from invasive bacterial infections, and the vaccines designed to prevent them, may promote T cell activation and enhancement of HIV-1 replication. Changes in viral load have been correlated with antigen-specific responses. We prospectively determined the impact of immunization with 23-valent pneumococcal vaccine (PVAX) and Haemophilus influenzae type b (Hib)-modified diphtheria toxoid CRM197 (DT) vaccine on HIV-1 replication in recent HIV-1 seroconverters (n = 14; median, 5.5 months from infection; median CD4+ T cells, 535 microl), and correlated results with vaccine-related immune activation. Specific antibody responses, markers of CD4+ T cell activation (transferrin and interleukin 2 receptors), and viral burden were measured at weeks -2 (pre), 0, 1, 2, 6, and 12 after immunization. By week 2, levels of IgG had increased significantly over baseline in both HIV-1-infected patients and HIV-1-seronegative control subjects (n = 9) for each antigen (geometric mean fold rise: PVAX, 10.1 versus 5.3; Hib, 16.0 versus 11.7; and DT, 26.2 versus 24.5, respectively). Despite these vigorous responses to both polysaccharide and protein antigens, HIV-1-infected patients showed limited evidence of CD4+ T cell activation at 1 week, no consistent rise in HIV-1 burden at any point, and no decline in CD4+ T cell number over time. We conclude that recent HIV-1 seroconverters show vigorous humoral responses to vaccine antigens and limited early evidence of T cell activation, but no substantial or sustained increase in viral replication or decline in CD4+ T cell number. Thus, respiratory bacterial vaccines appear immunogenic and safe early in HIV-1 infection.

Immunosuppressive therapy for ulcerative colitis: results of a nation-wide survey among consultant physician members of the British Society of Gastroenterology

BACKGROUND

The role of immunosuppressive therapy in ulcerative colitis remains controversial. There is little information available on how frequently immunosuppressives are used, the circumstances, dose and duration of use and perceived benefit.

METHODS

A postal survey was sent to consultant gastroenterologist members of the British Society of Gastroenterology.

RESULTS

Questionnaires were returned by 81% of the 496 UK consultants approached. Azathioprine use was frequent, with 93% reporting previous use and 86% use within the past year. Although 95% usually prescribed a < or =2 mg/kg dose, only 39% were prepared to prescribe higher doses. There was marked variation in duration of use, with 46% using azathioprine for <2 years and 17% continuing it for 4 years or longer. Consultants with more experience of azathioprine in ulcerative colitis used it at higher maintenance doses for longer periods, and in patients with less extensive disease. Cyclosporin use was reported by 47% of those caring for ulcerative colitis patients, with 36% having used it at least once in the past year. However, 65% of users estimated that fewer than 50% of patients subsequently avoided colectomy. On stopping cyclosporin only 21% always introduced an alternative immunosuppressive, while 23% never did so. Potentially serious side-effects attributable to azathioprine and cyclosporin were reported by 36% and 45% of users of each drug, respectively.

CONCLUSIONS

This survey reveals considerable variation in the amount and pattern of immunosuppressive use in ulcerative colitis, with serious side-effects commonly seen. There is a pressing need for further randomized controlled trials to provide reliable evidence as to how immunosuppressive therapy should be used in ulcerative colitis.

Measuring community/environmental interventions: the Child Pedestrian Injury Prevention Project

OBJECTIVES

To assess the effectiveness of community/environmental interventions undertaken as part of the Child Pedestrian Injury Prevention Project (CPIPP).

SETTING

Three communities (local government areas) in the Perth metropolitan area, Western Australia.

METHODS

A quasiexperimental community intervention trial was undertaken over three years (1995-97). Three communities were assigned to either: a community/environmental road safety intervention and a school based road/pedestrian safety education program (intervention group 1); a school based road/pedestrian safety education program only (intervention group 2); or to no road safety intervention (comparison group). Quantification of the various road safety community/environmental activities undertaken in each community during the trial was measured, and a cumulative community activity index developed. Estimates of the volume and speed of vehicular traffic were monitored over a two year period.

RESULTS

Greater road safety activity was observed in intervention group 1 compared with the other groups. A significant reduction in the volume of traffic on local access roads was also observed over the period of the trial in intervention group 1, but not in the remaining groups.

CONCLUSIONS

The findings indicate that the various community/environmental interventions initiated in collaboration with CPIPP in intervention group 1 contributed, in part, to the observed reduction in the volume of traffic. A combination of community/environmental interventions and education are likely to reduce the rate of childhood pedestrian injury.

Establishment of a functional human immunodeficiency virus type 1 (HIV-1) reverse transcription complex involves the cytoskeleton

After interaction of human immunodeficiency virus type 1 (HIV-1) virions with cell surface receptors, a series of poorly characterized events results in establishment of a viral reverse transcription complex in the host cell cytoplasm. This process is coordinated in such a way that reverse transcription is initiated shortly after formation of the viral reverse transcription complex. However, the mechanism through which virus entry and initiation of reverse transcription are coordinated and how these events are compartmentalized in the infected cell are not known. In this study, we demonstrate that viral reverse transcription complexes associate rapidly with the host cell cytoskeleton during HIV-1 infection and that reverse transcription occurs almost entirely in the cytoskeletal compartment. Interruption of actin polymerization before virus infection reduced association of viral reverse transcription complexes with the cytoskeleton. In addition, efficient reverse transcription was dependent on intact actin microfilaments. The localization of reverse transcription to actin microfilaments was mediated by the interaction of a reverse transcription complex component (gag MA) with actin but not vimentin (intermediate filaments) or tubulin (microtubules). In addition, fusion, but not endocytosis-mediated HIV-1 infectivity, was impaired when actin depolymerizing agents were added to target cells before infection but not when added after infection. These results point to a previously unsuspected role for the host cell cytoskeleton in HIV-1 entry and suggest that components of the cytoskeleton promote establishment of the reverse transcription complex in the host cell and also the process of reverse transcription within this complex.

Vpx is required for dissemination and pathogenesis of SIV(SM) PBj: evidence of macrophage-dependent viral amplification

The viral accessory protein Vpx is required for productive in vitro infection of macrophages by simian immunodeficiency virus from sooty mangabey monkeys (SIV(SM)). To evaluate the roles of Vpx and macrophage infection in vivo, we inoculated pigtailed macaques intravenously or intrarectally with the molecularly cloned, macrophage tropic, acutely pathogenic virus SIV(SM) PBj 6.6, or accessory gene deletion mutants (deltaVpr or deltaVpx) of this virus. Both wild-type and SIV(SM) PBj deltaVpx viruses were readily transmitted across the rectal mucosa. A subsequent 'stepwise' process of local amplification of infection and dissemination was observed for wild-type virus, but not for SIV(SM) PBj deltaVpx, which also showed considerable impairment of the overall kinetics and extent of its replication. In animals co-inoculated with equivalent amounts of wild-type and SIV(SM) Pbj deltaVpx intravenously or intrarectally, the deltaVpx mutant was at a strong competitive disadvantage. Vpx-dependent viral amplification at local sites of initial infection, perhaps through a macrophage-dependent mechanism, may be a prerequisite for efficient dissemination of infection and pathogenic consequences after exposure through either mucosal or intravenous routes.

Can patients predict which consultations can be dealt with by telephone?

The use of telephone consultations to reduce the workload of general practitioners is well established both in this country and abroad. The principal aim of this study was to discover the proportion of consultations currently carried out in the surgery that would be suitable, for both doctor and patient, to be managed over the telephone. The second aim was to establish what proportion of such consultations could be predicted.

Comparative analysis of crossover exchanges and chiasmata in Allium cepa x fistulosum after genomic in situ hybridization (GISH)

Genomic in situ hybridization (GISH) successfully differentiated homoeologous genomes in the inter-specific hybrid Allium cepa x fistulosum, thus allowing the detection of reciprocal crossover events as label exchanges in separating anaphase I chromosomes. Three of the eight chromosome pairs were positively identified by fluorescence in situ hybridization (FISH) to rDNA sequences. There was a general similarity of the GISH-based label exchange frequencies and metaphase I chiasma frequencies, but with a 20% deficit of chiasmata. Reasons for this apparent deficit are discussed. The locations of chiasmata and label exchanges are in broad agreement.

A retrospective comparison of craniofacial form in Northern Irish children with unilateral cleft lip and palate

OBJECTIVE

This study evaluated the craniofacial form of a sample of Northern Irish children with unilateral cleft lip and palate (UCLP). The quality of the outcomes achieved was compared with the outcomes reported for the six centers involved in the European multicenter study (Mars et al., 1992; Mølsted et al, 1992).

DESIGN

Retrospective analysis.

PATIENTS

All children born with complete skeletal UCLP in Northern Ireland during the years 1983 to 1987.

MAIN OUTCOME MEASURES

Cephalometric analysis was used to determine the craniofacial form and soft tissue profile. The quality of the dental arch relationships was independently assessed using the Goslon ranking system.

RESULTS

The sample comprised 25 children with complete skeletal UCLP who had cephalometric radiographs and study casts recorded at a mean age of 9.4 years (range, 8 to 11 years). Cephalometric analysis revealed no important skeletal differences between the Northern Irish UCLP children and the published results from the six Eurocleft centers. The soft tissue profile of the Northern Irish UCLP children was significantly more convex than the soft tissue profile recorded for center D in the Eurocleft study. The Goslon ranking system revealed that 18 (72%) of the Northern Irish UCLP children had good or satisfactory dental arch relationships.

CONCLUSIONS

No clinically important differences were detected between the mean cephalometric skeletal parameters of the Northern Irish UCLP children and those published for the six cleft centers involved in the Eurocleft study. On average, the Northern Irish UCLP children were found to differ significantly from Eurocleft's center D in their soft tissue facial contour and sagittal lip profile. The quality of the dental arch relationships of the Northern Irish sample was between the best and the less good Eurocleft centers.

Differential association of uracil DNA glycosylase with SIVSM Vpr and Vpx proteins

The HIV-1 Vpr protein is a virion-associated protein which has been shown to facilitate infection of nondividing macrophages and additionally to alter cell cycle and proliferation status of the infected host cell. HIV-1 Vpr also was recently shown to associate with the DNA repair enzyme uracil DNA glycosylase (UDG). This association with a DNA repair enzyme is intriguing given that nonprimate lentiviruses encode a dUTPase, which, like UDG, minimizes the misincorporation of uracil into DNA and is important for virus replication in primary nondividing macrophages but not in dividing cells. This raises the possibility that the dependence upon Vpr for infection of nondividing macrophages may relate to its ability to interact with UDG. Members of the HIV-2/SIVSM group encode, in addition to Vpr, a related protein called Vpx. We previously demonstrated (Fletcher et al., 1996) that Vpx of HIV-2/SIVSM is necessary and sufficient for infection of primary macaque macrophages, while Vpr is not required for macrophage infection but governs cell cycle arrest. Here, we extend on these observations by demonstrating that Vpr, but not Vpx of HIV-2/SIVSM, associates with UDG, which suggests that Vpx facilitates infection of macrophages by a UDG-independent mechanism.

The two communities in Northern Ireland: deprivation and ill health

BACKGROUND

The aim of this study was to examine differences in socio-economic standing and ill health between the two communities in Northern Ireland.

METHODS

This was a descriptive epidemiological study. Deaths from 1991 to 1995 inclusive were used to calculate standardized mortality rates (SMR, under 75 years) at small level using the 1991 Census population estimates. The standardized limiting long-term illness ratios (SIR) were based on the appropriate Census question. Regression models were tested with SMR and SIR as dependent variables and a wide range of socio-economic indicators, including income support and family credit uptake, as independent predictors.

RESULTS

Northern Ireland is a very polarized society. More than 60 per cent of the population live in areas which have more than 80 per cent of one religion. Areas with a preponderance of Catholics tend to be more deprived. Unemployment rates, percentage renting, car availability, and education attainment are all worse in Catholic areas. However, there is considerable heterogeneity between areas with similar levels of religious affiliation and the overall pattern varies with the indicator chosen. SMRs rise stepwise with increasing percentage of Catholics. SIRs increase with increasing polarization of areas, but this is much more marked in those with a predominantly Catholic affiliation. Altogether 46.8 per cent of the variance in SMR and 77.9 per cent of that of SIRs could be explained by socio-economic variables alone. Denomination did not have any residual predictive value.

CONCLUSIONS

Policy-makers should continue to periodically monitor for differences between the two communities including any differences in service accessibility and uptake. Efforts should be directed towards reducing the inequalities in health for all sections of the community.

Modulation of HIV-1 infectivity by MAPK, a virion-associated kinase

Infection of a cell by human immunodeficiency virus type 1 (HIV-1) results in the formation of a reverse transcription complex in which viral nucleic acids are synthesized. Efficient disengagement of the reverse transcription complex from the cell membrane and subsequent nuclear translocation require phosphorylation of reverse transcription complex components by a virion-associated kinase. In this study, we identify the virion-associated kinase as mitogen-activated protein kinase (ERK/MAPK). Upon density gradient fractionation, MAPK, but not its activating kinase MEK, co-sedimented with viral particles. Expression of a constitutively active, but not kinase-inactive, MEK1 in virus producer cells was able to activate virion-associated MAPK in trans. Stimulation of virion-associated MAPK activity in trans by the mitogen phorbol myristate acetate (PMA) increased viral infectivity. Conversely, suppression of virion-associated MAPK by specific inhibitors of the MAPK cascade markedly impaired viral infectivity. These studies demonstrate regulation of an early step in HIV-1 infection by the host cell MAPK signal transduction pathway.

New advances and validation of knowledge management tools for critical care using classifier techniques

An earlier version (2.0) of the case-based reasoning (CBR) tool, called IDEAS for ICU's, allowed users to compare the ten closest matching cases to the newest patient admission, using a large database of intensive care patient records, and physician-selected matching-weights [1,2]. The new version incorporates matching-weights, which have been determined quantitatively. A faster CBR matching engine has also been incorporated into the new CBR. In a second approach, a back-propagation, feed-forward artificial neural network estimated two classes of the outcome "duration of artificial ventilation" for a subset of the database used for the CBR work. Weight-elimination was successfully applied to reduce the number of input variables and speed-up the estimation of outcomes. New experiments examined the impact of using a different number of input variables on the performance of the ANN, measured by correct classification rates (CCR) and the Average Squared Error (ASE).

Women with recurrent vaginal candidosis have normal peripheral blood B and T lymphocyte subset levels

OBJECTIVE

To compare the B and T lymphocyte subset levels of otherwise healthy women suffering from frequently recurrent vaginal candidosis with a healthy control group.

SUBJECTS

26 unselected otherwise healthy women of reproductive age with at least four attacks of vaginal candidosis in the past year and more than three vaginal isolates of a moderate or heavy growth of Candida albicans. Controls were 26 patients or clinical and laboratory staff (asymptomatic for genital infection) matched for time of day and age within 5 years. Only three patients accepted an HIV test. All proved HIV negative. No controls were tested.

MAIN OUTCOME MEASURES

T lymphocyte subsets (CD4 and 8) and B lymphocytes (CD 19) as estimated from the total lymphocyte count and flow cytometry.

RESULTS

No statistically significant difference between patients and controls.

CONCLUSION

No significant difference was found between patients and controls in levels of lymphocyte subsets.

The PRECEDE-PROCEED model: application to planning a child pedestrian injury prevention program

OBJECTIVES

The objectives were first, to modify the PRECEDE-PROCEED model and to use it is as a basis for planning a three year intervention trial that aims to reduce injury to child pedestrians. A second objective was to assess the suitability of this process for planning such a relatively complex program.

SETTING

The project was carried out in 47 primary schools in three local government areas, in the Perth metropolitan area.

METHODS

The program was developed, based on extensive needs assessment incorporating formative evaluations. Epidemiological, psychosocial, environmental, educational, and demographic information was gathered, organised, and prioritised. The PRECEDE-PROCEED model was used to identify the relevant behavioural and environmental risk factors associated with child pedestrian injuries in the target areas. Modifiable causes of those behavioural and environmental factors were delineated. A description of how the model facilitated the development of program objectives and subobjectives which were linked to strategy objectives, and strategies is provided.

RESULTS

The process used to plan the child pedestrian injury prevention program ensured that a critical assessment was undertaken of all the relevant epidemiological, behavioural, and environmental information. The gathering, organising, and prioritising of the information was facilitated by the process.

CONCLUSIONS

The use of a model such as PRECEDE-PROCEED can enhance the development of a child injury prevention program. In particular, the process can facilitate the identification of appropriate objectives which in turn facilitates the development of suitable interventions and evaluation methods.