SARS-CoV-2 Omicron BA.5: Evolving tropism and evasion of potent humoral responses and resistance to clinical immunotherapeutics relative to viral variants of concern

BACKGROUND

Genetically distinct viral variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been recorded since January 2020. The introduction of global vaccine programs has contributed to lower COVID-19 hospitalisation and mortality rates, particularly in developed countries. In late 2021, Omicron BA.1 emerged, with substantially altered genetic differences and clinical effects from other variants of concern. Shortly after dominating global spread in early 2022, BA.1 was supplanted by the genetically distinct Omicron lineage BA.2. A sub-lineage of BA.2, designated BA.5, presently has an outgrowth advantage over BA.2 and other BA.2 sub-lineages. Here we study the neutralisation of Omicron BA.1, BA.2 and BA.5 and pre-Omicron variants using a range of vaccine and convalescent sera and therapeutic monoclonal antibodies using a live virus neutralisation assay. Using primary nasopharyngeal swabs, we also tested the relative fitness of BA.5 compared to pre-Omicron and Omicron viral lineages in their ability to use the ACE2-TMPRSS2 pathway.

METHODS

Using low passage clinical isolates of Clade A.2.2, Beta, Delta, BA.1, BA.2 and BA.5, we determined humoral neutralisation in vitro in vaccinated and convalescent cohorts, using concentrated human IgG pooled from thousands of plasma donors, and licensed monoclonal antibody therapies. We then determined infectivity to particle ratios in primary nasopharyngeal samples and expanded low passage isolates in a genetically engineered ACE2/TMPRSS2 cell line in the presence and absence of the TMPRSS2 inhibitor Nafamostat.

FINDINGS

Peak responses to 3 doses of BNT162b2 vaccine were associated with a 9-fold reduction in neutralisation for Omicron lineages BA.1, BA.2 and BA.5. Concentrated pooled human IgG from convalescent and vaccinated donors and BNT162b2 vaccination with BA.1 breakthrough infections were associated with greater breadth of neutralisation, although the potency was still reduced 7-fold across all Omicron lineages. Testing of clinical grade antibodies revealed a 14.3-fold reduction using Evusheld and 16.8-fold reduction using Sotrovimab for the BA.5. Whilst the infectivity of BA.1 and BA.2 was attenuated in ACE2/TMPRSS2 entry, BA.5 was observed to be equivalent to that of an early 2020 circulating clade and had greater sensitivity to the TMPRSS2 inhibitor Nafamostat.

INTERPRETATION

Observations support all Omicron variants to significantly escape neutralising antibodies across a range of vaccination and/or convalescent responses. Potency of therapeutic monoclonal antibodies is also reduced and differs across Omicron lineages. The key difference of BA.5 from other Omicron sub-variants is the reversion in tropism back to using the well-known ACE2-TMPRSS2 pathway, utilised efficiently by pre-Omicron lineages. Monitoring if these changes influence transmission and/or disease severity will be key for ongoing tracking and management of Omicron waves globally.

FUNDING

This work was primarily supported by Australian Medical Foundation research grants MRF2005760 (ST, GM & WDR), MRF2001684 (ADK and ST) and Medical Research Future Fund Antiviral Development Call grant (WDR), Medical Research Future Fund COVID-19 grant (MRFF2001684, ADK & SGT) and the New South Wales Health COVID-19 Research Grants Round 2 (SGT).

SARS-CoV-2 Omicron BA.5: Evolving tropism and evasion of potent humoral responses and resistance to clinical immunotherapeutics relative to viral variants of concern

BACKGROUND

Genetically distinct viral variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been recorded since January 2020. The introduction of global vaccine programs has contributed to lower COVID-19 hospitalisation and mortality rates, particularly in developed countries. In late 2021, Omicron BA.1 emerged, with substantially altered genetic differences and clinical effects from other variants of concern. Shortly after dominating global spread in early 2022, BA.1 was supplanted by the genetically distinct Omicron lineage BA.2. A sub-lineage of BA.2, designated BA.5, presently has an outgrowth advantage over BA.2 and other BA.2 sub-lineages. Here we study the neutralisation of Omicron BA.1, BA.2 and BA.5 and pre-Omicron variants using a range of vaccine and convalescent sera and therapeutic monoclonal antibodies using a live virus neutralisation assay. Using primary nasopharyngeal swabs, we also tested the relative fitness of BA.5 compared to pre-Omicron and Omicron viral lineages in their ability to use the ACE2-TMPRSS2 pathway.

METHODS

Using low passage clinical isolates of Clade A.2.2, Beta, Delta, BA.1, BA.2 and BA.5, we determined humoral neutralisation in vitro in vaccinated and convalescent cohorts, using concentrated human IgG pooled from thousands of plasma donors, and licensed monoclonal antibody therapies. We then determined infectivity to particle ratios in primary nasopharyngeal samples and expanded low passage isolates in a genetically engineered ACE2/TMPRSS2 cell line in the presence and absence of the TMPRSS2 inhibitor Nafamostat.

FINDINGS

Peak responses to 3 doses of BNT162b2 vaccine were associated with a 9-fold reduction in neutralisation for Omicron lineages BA.1, BA.2 and BA.5. Concentrated pooled human IgG from convalescent and vaccinated donors and BNT162b2 vaccination with BA.1 breakthrough infections were associated with greater breadth of neutralisation, although the potency was still reduced 7-fold across all Omicron lineages. Testing of clinical grade antibodies revealed a 14.3-fold reduction using Evusheld and 16.8-fold reduction using Sotrovimab for the BA.5. Whilst the infectivity of BA.1 and BA.2 was attenuated in ACE2/TMPRSS2 entry, BA.5 was observed to be equivalent to that of an early 2020 circulating clade and had greater sensitivity to the TMPRSS2 inhibitor Nafamostat.

INTERPRETATION

Observations support all Omicron variants to significantly escape neutralising antibodies across a range of vaccination and/or convalescent responses. Potency of therapeutic monoclonal antibodies is also reduced and differs across Omicron lineages. The key difference of BA.5 from other Omicron sub-variants is the reversion in tropism back to using the well-known ACE2-TMPRSS2 pathway, utilised efficiently by pre-Omicron lineages. Monitoring if these changes influence transmission and/or disease severity will be key for ongoing tracking and management of Omicron waves globally.

FUNDING

This work was primarily supported by Australian Medical Foundation research grants MRF2005760 (ST, GM & WDR), MRF2001684 (ADK and ST) and Medical Research Future Fund Antiviral Development Call grant (WDR), Medical Research Future Fund COVID-19 grant (MRFF2001684, ADK & SGT) and the New South Wales Health COVID-19 Research Grants Round 2 (SGT).

Renal Transplantation in Children Treated with Continuous Ambulatory Peritoneal Dialysis

Over the last three years 23 children, who were managed by CAPD at the Hospital for Sick Children, Toronto received a renal transplant. Their actuarial graft survival was similar to those of children on hemodialysis and to patients not dialyzed before transplantation. In addition, we analyzed the actuarial graft survival of 130 children treated before transplantation with peritoneal dialysis (IPD and CAPD), hemodialysis or no dialysis to determine the long-term effects of peritoneal dialysis. Again, we found no significant differences among the various groups. Posttransplantation complications in the CAPD patients included fungal peritonitis in one and ascites in seven.

Possible clearance of transfusion-acquired nef/LTR-deleted attenuated HIV-1 infection by an elite controller with CCR5 Δ32 heterozygous and HLA-B57 genotype

BACKGROUND

Subject C135 is one of the members of the Sydney Blood Bank Cohort, infected in 1981 through transfusion with attenuated nef/3' long terminal repeat (LTR)-deleted HIV-1, and has maintained undetectable plasma viral load and steady CD4 cell count, in the absence of therapy. Uniquely, C135 combines five factors separately associated with control of viraemia: nef/LTR-deleted HIV-1, HLA-B57, HLA-DR13, heterozygous CCR5 Δ32 genotype and vigorous p24-stimulated peripheral blood mononuclear cell (PBMC) proliferation. Therefore, we studied in detail viral burden and immunological responses in this individual.

METHODS

PBMC and gut and lymph node biopsy samples were analysed for proviral HIV-1 DNA by real-time and nested PCRs, and nef/LTR alleles by nested PCR. HIV-specific antibodies were studied by Western blotting, and CD4+ and CD8+ T lymphocyte responses were measured by proliferation and cytokine production in vitro.

RESULTS

PBMC samples from 1996, but not since, showed amplification of nef alleles with gross deletions. Infectious HIV-1 was never recovered. Proviral HIV-1 DNA was not detected in recent PBMC or gut or lymph node biopsy samples. C135 has a consistently weak antibody response and a substantial CD4+ T cell proliferative response to a previously described HLA-DR13-restricted epitope of HIV-1 p24 in vitro, which augmented a CD8+ T cell response to an immunodominant HLA-B57-restricted epitope of p24, while his T cells show reduced levels of CCR5.

CONCLUSIONS

Subject C135's early PCR and weak antibody results are consistent with limited infection with a poorly replicating nef/LTR-deleted strain of HIV-1. With his HLA-B57-restricted gag-specific CD8 and helper HLA-DR13-restricted CD4 T cell proliferative responses, C135 appears to have cleared his HIV-1 infection 37 years after transfusion.

Increased hypothalamic microglial activation after viral-induced pneumococcal lung infection is associated with excess serum amyloid A production

Background

It is well established that lung pathology and inflammation are more severe during respiratory infections complicated by the presence of both bacteria and viruses. Whilst co-infection can result in invasive pneumococcal disease and systemic inflammation, the neuroinflammatory consequences of co-infection are poorly characterised.

Methods

In this study, we utilised a mouse co-infection model involving Streptococcus pneumoniae (S. pneumoniae) and influenza A virus (IAV) lung infection, and we also isolated microglia for ex vivo stimulation with pneumococcus or serum amyloid A (SAA).

Results

Co-infection but not S. pneumoniae or IAV alone significantly increased the number of amoeboid-shaped microglia and expression of pro-inflammatory cytokines including tumour necrosis factor α (TNFα), interleukin-1β (IL-1β), interleukin-6 (IL-6), and C-C motif chemokine ligand-2 (CCL-2) in the hypothalamus. Pneumococcus was only detected in the hypothalamus of co-infected mice. In addition, the systemic inflammatory cytokines TNFα, IL-1β and IL-6 were not elevated in co-infected mice relative to IAV-infected mice, whereas SAA levels were markedly increased in co-infected mice (p < 0.05). SAA and its functional receptor termed formyl peptide receptor 2 (Fpr2) transcript expression were also increased in the hypothalamus. In mouse primary microglia, recombinant SAA but not S. pneumoniae stimulated TNFα, IL-1β, IL-6 and CCL-2 expression, and this response was completely blocked by the pro-resolving Fpr2 agonist aspirin-triggered resolvin D1 (AT-RvD1).

Conclusions

In summary, lung co-infection increased the number of ‘activated’ amoeboid-shaped microglia and inflammatory cytokine expression in the hypothalamus. Whilst persistent pneumococcal brain infection was observed, SAA proved to be a much more potent stimulus of microglia than pneumococci, and this response was potently suppressed by the anti-inflammatory AT-RvD1. Targeting Fpr2 with pro-resolving eicosanoids such as AT-RvD1 may restore microglial homeostasis during severe respiratory infections.

Electronic supplementary material

The online version of this article (10.1186/s12974-018-1234-1) contains supplementary material, which is available to authorized users.

Analysis of Clinical HIV-1 Strains with Resistance to Maraviroc Reveals Strain-Specific Resistance Mutations, Variable Degrees of Resistance, and Minimal Cross-Resistance to Other CCR5 Antagonists

Maraviroc (MVC) is an allosteric inhibitor of human immunodeficiency virus type 1 (HIV-1) entry, and is the only CCR5 antagonist licensed for use as an anti-HIV-1 therapeutic. It acts by altering the conformation of the CCR5 extracellular loops, rendering CCR5 unrecognizable by the HIV-1 envelope (Env) glycoproteins. This study aimed to understand the mechanisms underlying the development of MVC resistance in HIV-1-infected patients. To do this, we obtained longitudinal plasma samples from eight subjects who experienced treatment failure with phenotypically verified, CCR5-tropic MVC resistance. We then cloned and characterized HIV-1 Envs (n = 77) from plasma of pretreatment (n = 36) and treatment failure (n = 41) samples. Our results showed variation in the magnitude of MVC resistance as measured by reductions in maximal percent inhibition of Env-pseudotyped viruses, which was more pronounced in 293-Affinofile cells compared to other cells with similar levels of CCR5 expression. Amino acid determinants of MVC resistance localized to the V3 Env region and were strain specific. We also observed minimal cross-resistance to other CCR5 antagonists by MVC-resistant strains. We conclude that 293-Affinofile cells are highly sensitive for detecting and measuring MVC resistance through a mechanism that is CCR5-dependent yet independent of CCR5 expression levels. The strain-specific nature of resistance mutations suggests that sequence-based diagnostics and prognostics will need to be more sophisticated than simple position scoring to be useful for managing resistance in subjects taking MVC. Finally, the minimal levels of cross-resistance suggests that recognition of the MVC-modified form of CCR5 does not necessarily lead to recognition of other antagonist-modified forms of CCR5.

A HIV-Tat/C4-binding protein chimera encoded by a DNA vaccine is highly immunogenic and contains acute EcoHIV infection in mice

DNA vaccines are cost-effective to manufacture on a global scale and Tat-based DNA vaccines have yielded protective outcomes in preclinical and clinical models of human immunodeficiency virus (HIV), highlighting the potential of such vaccines. However, Tat-based DNA vaccines have been poorly immunogenic, and despite the administration of multiple doses and/or the addition of adjuvants, these vaccines are not in general use. In this study, we improved Tat immunogenicity by fusing it with the oligomerisation domain of a chimeric C4-binding protein (C4b-p), termed IMX313, resulting in Tat heptamerisation and linked Tat to the leader sequence of tissue plasminogen activator (TPA) to ensure that the bulk of heptamerised Tat is secreted. Mice vaccinated with secreted Tat fused to IMX313 (pVAX-sTat-IMX313) developed higher titres of Tat-specific serum IgG, mucosal sIgA and cell-mediated immune (CMI) responses, and showed superior control of EcoHIV infection, a surrogate murine HIV challenge model, compared with animals vaccinated with other test vaccines. Given the crucial contribution of Tat to HIV-1 pathogenesis and the precedent of Tat-based DNA vaccines in conferring some level of protection in animal models, we believe that the virologic control demonstrated with this novel multimerised Tat vaccine highlights the promise of this vaccine candidate for humans.

Designer antigens for elicitation of broadly neutralizing antibodies against HIV

Broadly neutralizing antibodies (bNAbs) are a consistent protective immune correlate in human immunodeficiency virus (HIV) patients as well as in passive immunotherapy studies. The inability to elicit bNAbs is the core reason underlining the repeated failures in traditional HIV vaccine research. Rare monoclonal bNAbs against HIV, however, have been produced. The significance of producing and studying more monoclonal bNAbs against HIV is underlined by its capability of defining critical epitopes for antigen designs aimed at the development of a serum-neutralizing HIV vaccine. In this regard, traditional antigen preparations have failed. There is a need to clearly advocate the concept, and systematic study, of more sophisticated 'designer antigens' (DAGs), which carry epitopes that can lead to the elicitation of bNAbs. Using an extremely efficient cell-to-cell HIV infection model for the preparation of HIV prefusion intermediates, we have investigated a novel and systematic approach to produce (not screen for) potential bNAbs against HIV. We have established the concept and the experimental system for producing formaldehyde-fixed HIV DAGs that carry temperature-arrested prefusion intermediates. These prefusion intermediates are structures on the cell surface after viral attachment and receptor engagement but before fully functional viral entry. Using defined HIV prefusion DAGs, we have produced monoclonal antibodies (mAbs) specific to novel epitopes on HIV prefusion intermediates. These mAbs do not react with the static/native surface HIV or cellular antigens, but react with the DAGs. This is a paradigm shift from the current mainstream approach of screening elite patients' bNAbs.

Observation of edge instability limiting the pedestal growth in tokamak plasmas

With fusion device performance hinging on the edge pedestal pressure, it is imperative to experimentally understand the physical mechanism dictating the pedestal characteristics and to validate and improve pedestal predictive models. This Letter reports direct evidence of density and magnetic fluctuations showing the stiff onset of an edge instability leading to the saturation of the pedestal on the Alcator C-Mod tokamak. Edge stability analyses indicate that the pedestal is unstable to both ballooning mode and kinetic ballooning mode in agreement with observations.

Entinostat is a histone deacetylase inhibitor selective for class 1 histone deacetylases and activates HIV production from latently infected primary T cells

OBJECTIVES

To compare the potency, toxicity and mechanism of action of multiple histone deacetylase inhibitors (HDACi) in activating HIV production from latency.

DESIGN

In-vitro analysis of HDACi in a primary T-cell model of HIV latency and latently infected cell lines.

METHODS

Latently infected chemokine ligand 19 (CCL19)-treated CD4⁺ T cells and the latently infected cell lines ACH2 and J-Lat were treated with a panel of HDACi, including entinostat, vorinostat, panonbinostat and MCT3. Viral production and cell viability were compared. Expression of cellular HDACs was measured by western blot and PCR. Association of HDACs with the HIV long-terminal repeat (LTR) using latently infected CCL19-treated primary CD4⁺ T cells in the presence and absence of specific HDACi was determined by chromatin immunoprecipitation (ChIP).

RESULTS

We demonstrated considerable variation in the potency and toxicity of HDACi in latently infected primary CD4⁺ T cells and cell lines. All HDACi tested activated HIV production in latently infected primary T cells with greatest potency demonstrated with entinostat and vorinostat and greatest toxicity with panobinostat. Following the addition of HDACi in vitro, there were no changes in markers of T-cell activation or expression of the HIV coreceptors chemokine (C-X-C motif) receptor 4 (CXCR4) or chemokine (C-C motif) receptor type 5 (CCR5). ChIP analysis of latently infected CCL19-treated primary CD4⁺ T cells showed binding by HDAC1, HDAC2 and HDAC3 to the LTR with removal of HDAC1 and HDAC2 following treatment with the HDACi vorinostat and HDAC1 only following treatment with entinostat.

CONCLUSION

The HDACi entinostat, selective for inhibition of class I HDACs, induced virus expression in latently infected primary CD4⁺ T cells making this compound an attractive novel option for future clinical trials.

Is specific HIV eradication from the brain possible or needed?

INTRODUCTION

There is increasing interest in the possibility of eradication of HIV, given the recent case reports. However, it is not clear to what extent brain involvement by HIV poses a challenge to systemic eradication strategies.

AREAS COVERED

This review will outline the mechanisms of HIV latency, the various eradication strategies presently under consideration followed by a discussion of the issue of the frequency and severity of brain involvement by HIV. In those patients with HIV brain disease the challenges will be delineated as well as potential approaches to circumvent or minimise them.

EXPERT OPINION

Eradication of HIV from the brain using specific methodologies is likely only needed in some patients. However, both the identification of such patients and the details of the necessary methodologies require much more research.

Towards an HIV cure: a global scientific strategy

Given the limitations of antiretroviral therapy and recent advances in our understanding of HIV persistence during effective treatment, there is a growing recognition that a cure for HIV infection is both needed and feasible. The International AIDS Society convened a group of international experts to develop a scientific strategy for research towards an HIV cure. Several priorities for basic, translational and clinical research were identified. This Opinion article summarizes the group's recommended key goals for the international community.

Blackawton bees

BACKGROUND

Real science has the potential to not only amaze, but also transform the way one thinks of the world and oneself. This is because the process of science is little different from the deeply resonant, natural processes of play. Play enables humans (and other mammals) to discover (and create) relationships and patterns. When one adds rules to play, a game is created.

THIS IS SCIENCE

the process of playing with rules that enables one to reveal previously unseen patterns of relationships that extend our collective understanding of nature and human nature. When thought of in this way, science education becomes a more enlightened and intuitive process of asking questions and devising games to address those questions. But, because the outcome of all game-playing is unpredictable, supporting this 'messyness', which is the engine of science, is critical to good science education (and indeed creative education generally). Indeed, we have learned that doing 'real' science in public spaces can stimulate tremendous interest in children and adults in understanding the processes by which we make sense of the world. The present study (on the vision of bumble-bees) goes even further, since it was not only performed outside my laboratory (in a Norman church in the southwest of England), but the 'games' were themselves devised in collaboration with 25 8- to 10-year-old children. They asked the questions, hypothesized the answers, designed the games (in other words, the experiments) to test these hypotheses and analysed the data. They also drew the figures (in coloured pencil) and wrote the paper. Their headteacher (Dave Strudwick) and I devised the educational programme (we call 'i,scientist'), and I trained the bees and transcribed the childrens' words into text (which was done with smaller groups of children at the school's local village pub). So what follows is a novel study (scientifically and conceptually) in 'kids speak' without references to past literature, which is a challenge. Although the historical context of any study is of course important, including references in this instance would be disingenuous for two reasons. First, given the way scientific data are naturally reported, the relevant information is simply inaccessible to the literate ability of 8- to 10-year-old children, and second, the true motivation for any scientific study (at least one of integrity) is one's own curiousity, which for the children was not inspired by the scientific literature, but their own observations of the world. This lack of historical, scientific context does not diminish the resulting data, scientific methodology or merit of the discovery for the scientific and 'non-scientific' audience. On the contrary, it reveals science in its truest (most naive) form, and in this way makes explicit the commonality between science, art and indeed all creative activities.

PRINCIPAL FINDING

'We discovered that bumble-bees can use a combination of colour and spatial relationships in deciding which colour of flower to forage from. We also discovered that science is cool and fun because you get to do stuff that no one has ever done before. (Children from Blackawton)'.

Enhanced CD4+ cellular apoptosis by CCR5-restricted HIV-1 envelope glycoprotein variants from patients with progressive HIV-1 infection

CCR5-using (R5) human immunodeficiency virus type 1 (HIV-1) strains cause CD4+ T-cell loss in most infected individuals, but mechanisms underlying cytopathicity of R5 viruses are poorly understood. We investigated mechanisms contributing to R5 envelope glycoprotein (Env)-mediated cellular apoptosis by constructing a panel of retroviral vectors engineered to co-express GFP and R5 Envs derived from two HIV-1-infected subjects spanning asymptomatic (Early, E-R5 Envs) to late stages of infection (Late, L-R5 Envs). The L-R5 Envs induced significantly more cellular apoptosis than E-R5 Envs, but only in Env-expressing (GFP-positive) cells, and only in cells where CD4 and CCR5 levels were limiting. Studies with fusion-defective Env mutants showed induction of apoptosis required membrane-fusing events. Our results provide evidence for an intracellular mechanism of R5 Env-induced apoptosis of CD4+ cells that requires membrane fusion. Furthermore, they contribute to a better understanding of mechanisms involved in CD4+ T-cell loss in subjects experiencing progressive R5 HIV-1 infection.

Viral phenotypes and antibody responses in long-term survivors infected with attenuated human immunodeficiency virus type 1 containing deletions in the nef and long terminal repeat regions

The Sydney Blood Bank Cohort (SBBC) consists of eight blood transfusion recipients infected with nef-attenuated human immunodeficiency virus type 1 (HIV-1) acquired from a single donor. Here, we show that viral phenotypes and antibody responses differ considerably between individual cohort members, despite the single source of infection. Replication of isolated virus varied from barely detectable to similar to that of the wild-type virus, and virus isolated from five SBBC members showed coreceptor usage signatures unique to each individual. Higher viral loads and stronger neutralizing antibody responses were associated with better-replicating viral strains, and detectable viral replication was essential for the development of strong and sustained humoral immune responses. Despite the presence of strong neutralizing antibodies in a number of SBBC members, disease progression was not prevented, and each cohort member studied displayed a unique outcome of infection with nef-attenuated HIV-1.

Uncoupling coreceptor usage of human immunodeficiency virus type 1 (HIV-1) from macrophage tropism reveals biological properties of CCR5-restricted HIV-1 isolates from patients with acquired immunodeficiency syndrome

The mechanisms underlying the pathogenicity of CCR5-restricted (R5) human immunodeficiency virus type-1 (HIV-1) strains are incompletely understood. Acquisition or enhancement of macrophage (M)-tropism by R5 viruses contributes to R5 HIV-1 pathogenesis. In this study, we show that M-tropic R5 viruses isolated from individuals with acquired immunodeficiency syndrome (late R5 viruses) require lower levels of CD4/CCR5 expression for entry, have decreased sensitivity to inhibition by the entry inhibitors TAK-779 and T-20, and have increased sensitivity to neutralization by the Env MAb IgG1b12 compared with non-M-tropic R5 viruses isolated from asymptomatic, immunocompetent individuals (early R5 viruses). Augmenting CCR5 expression levels on monocyte-derived macrophages via retroviral transduction led to a complete or marginal restoration of M-tropism by early R5 viruses, depending on the viral strain. Thus, reduced CD4/CCR5 dependence is a phenotype of R5 HIV-1 associated with M-tropism and late stage infection, which may affect the efficacy of HIV-1 entry inhibitors.

Pathogenesis of macrophage tropic HIV-1

Despite numerous studies on the impact of viral diversity, human immunodeficiency virus type 1 (HIV-1)-specific immune responses and host factors on disease progression, we still do not have a firm understanding of the pathogenesis of HIV-1 infection. Rapid depletion of CD4+ T-lymphocytes has been associated with a switch in viral coreceptor usage from CCR5 to CXCR4 in approximately 40 to 50% of infected individuals. However, the majority of infected individuals who progress to AIDS harbor only CCR5-dependent (R5) viral strains. HIV-1 disease progression is associated with an enhanced tropism of R5 viral strains for cells of the monocyte/macrophage lineage (enhanced M-tropism). However, the underlying molecular mechanisms contributing to enhanced M-tropism by R5 HIV-1 strains, and how HIV-1 variants with enhanced M-tropism cause CD4+ T-cell depletion in vivo are unknown. This review examines the relationship between viral coreceptor usage, M-tropism, and pathogenicity of HIV-1. We highlight evidence supporting the hypothesis that enhanced M-tropism of R5 HIV-1 results from adaptive viral evolution, resulting in HIV-1 variants that have increased ability to utilize relatively low levels of CD4 and CCR5 expressed on macrophages. The evidence also suggests that these late-emerging, R5 viral strains have reduced sensitivity to entry inhibitors, and increased ability to cause CD4+ T-lymphocyte loss. These variants are likely to impact HIV-1 disease progression, particularly in patients who persistently harbor only R5 viral strains.

Longitudinal Analysis ofnef/Long Terminal Repeat–Deleted HIV‐1 in Blood and Cerebrospinal Fluid of a Long‐Term Survivor Who Developed HIV‐Associated Dementia

We studied the evolution and compartmentalization of nef/long terminal repeat (nef/LTR)-deleted human immunodeficiency virus type 1 (HIV-1) from a long-term survivor who developed HIV-associated dementia (HIVD). Analysis of sequential blood-derived HIV-1 isolated before and during HIVD revealed a persistent R5X4 phenotype and a progressive loss of nef/LTR sequence; in contrast, HIV-1 present in cerebrospinal fluid during HIVD had an R5 phenotype, distinct nef/LTR sequence of unique deletions and additional nuclear factor- kappa B sites and specificity factor-1 sites, and enhanced transcriptional activity, compared with the blood-derived isolates. Thus, nef/LTR-deleted HIV-1 strains may undergo compartmentalized evolution in long-term survivors and cause neurologic disease.

Mutational analysis of the HIV-1 LTR as a promoter of negative sense transcription

The HIV-1 gene promoter is a bi-directional promoter of transcription. We report the characterization of the negative sense promoter (NSP) by analysis of the effect on negative sense transcription of a series of LTR U3 region substitution mutants. Mutations in the region nt -58 to -183 (positive sense transcription initiation nt +1) reduced transcription to <15% of wild type NSP activity. This region, essential for NSP activity, was designated the core basal promoter. Over expression of NF-kappaB RelA(p65) and LEF-1 increased negative sense expression, as did over expression of H-ras oncogene, consistent with the presence of cognate sequence motifs for NF-kappaB, LEF-1 and RBF. We were also able to confirm that the NSP is a TATA-less promoter inhibited by HIV-1 Tat. Based on our findings, we propose a model for the interaction between the NSP and PSP, and the role of Tat in regulating the interaction.

The role of viral coreceptors and enhanced macrophage tropism in human immunodeficiency virus type 1 disease progression

Despite numerous studies on the impact of viral diversity, human immunodeficiency virus type 1 (HIV-1)-specific immune responses and host factors on disease progression, we still do not have a firm understanding of the long-term pathogenesis of HIV-1 infection. Rapid depletion of CD4+ T-lymphocytes has been associated with a switch in viral coreceptor usage from CCR5 to CXCR4 in ~40 to 50% of infected individuals. However, the majority of infected individuals who progress to AIDS harbour only CCR5-dependent (R5) viral strains. The progression HIV-1 disease is associated with an enhanced tropism of R5 viral strains for monocyte/macrophage lineage cells (enhanced M-tropism). However, the underlying molecular mechanisms contributing to enhanced M-tropism by R5 HIV-1 strains, and how HIV-1 variants with enhanced M-tropism cause CD4+ T-cell depletion in vivo are unknown. This review examines the relationship between viral coreceptor usage, M-tropism, and pathogenicity of HIV-1. We highlight evidence supporting the hypothesis that enhanced M-tropism of R5 HIV-1 results from adaptive viral evolution, resulting in HIV-1 variants that have increased ability to utilise relatively low levels of CCR5 expressed on macrophages, by way of increased CCR5 affinity. The evidence also suggests that these late-emerging, R5 viral strains have reduced sensitivity to entry inhibitors, and increased ability to cause CD4+ T-lymphocyte loss. These variants are likely to impact HIV-1 disease progression, especially in patients who persistently harbour only R5 viral strains.

Phagocytic Efficiency of Monocytes and Macrophages Obtained From Sydney Blood Bank Cohort Members Infected With an Attenuated Strain of HIV-1

Defective function of monocyte-derived macrophages contributes to HIV-1 pathogenesis. We found that phagocytosis of the opportunistic pathogens Mycobacterium avium complex and Toxoplasma gondii was impaired in monocytes obtained from individuals infected with wild-type strains of HIV-1 but generally not in monocytes collected over a 6-year period from Sydney Blood Bank Cohort (SBBC) members infected with nef/long terminal repeats (LTR) region-defective strains of HIV-1. However, longitudinal analysis of phagocytosis in 1 SBBC member, C54, showed the development of defective engulfment of opportunistic pathogens at the most recent time points, coincident with the development of further molecular deletions in the nef/LTR region. Another SBBC member, C98, underwent bronchoscopy, which provided material to examine phagocytic signaling in alveolar macrophages. In contrast to normal phagocytic efficiency of C98's monocytes (over a 6-year period), defective signaling events during FcgammaR-mediated phagocytosis by C98's alveolar macrophages were observed. High basal phosphorylation within HIV-infected macrophages correlated with colocalization of tyrosine-phosphorylated proteins with HIV-1 p24 antigen rather than around the phagocytic targets as observed in uninfected cells. Thus, although phagocytic efficiency appears to be generally unimpaired in monocytes from SBBC members, evidence of impairment in recent samples from 1 SBBC member, coincident with further genetic changes within the virus, and abnormal phagocytic signaling in alveolar macrophages from another SBBC member may herald loss of attenuation of those strains.

Inhibition of intestinal tumors by curcumin is associated with changes in the intestinal immune cell profile

BACKGROUND

The C57BL/6J-Min/+ (Min/+) mouse bears a germline mutation in Apc and is therefore a model for familial adenomatous polyposis and sporadic colorectal cancer. Min/+ intestinal mucosa exhibits a marked tendency for spontaneous adenoma formation. Curcumin is a phenolic antioxidant known for its antitumor and immune modulatory functions in vitro. Curcumin prevents adenoma formation in Min/+ mice, through a mechanism that may be related to its immunomodulatory properties.

MATERIALS AND METHODS

To study the relationship between intestinal immunity and curcumin-induced antitumor response, we used immunohistochemistry to characterize the effect of curcumin treatment on resident intestinal immune effector cells in Min/+ mice.

RESULTS/CONCLUSION

These results show that mucosal CD4(+) T cells and B cells increase in animals treated with curcumin, suggesting that curcumin modulates lymphocyte-mediated immune functions.

The effects of housing enrichment on cardiovascular parameters in spontaneously hypertensive rats

By using radiotelemetry, we measured blood pressure, heart rate, and locomotor activity in adult male spontaneously hypertensive (SHR) rats during three consecutive periods in which they received various social and non-social cage enrichments. The objective was to determine whether these enriching experiences would affect cardiovascular parameters. During the first period, the readings from four individually housed males, each with a telemetry transmitter in the abdominal cavity and connected to a femoral artery catheter, were compared to those from five similarly instrumented rats that were each housed with another rat. Systolic blood pressure and activity but not diastolic blood pressure or heart rate were higher in rats housed with another rat compared to those housed alone. During the second period, each cage of animals was enriched by including a large piece of plastic drainpipe and several golf balls. In addition, the nine animals were placed together daily for two hours at the beginning of the dark phase of the photoperiod in a large, three-tiered enclosure containing a running wheel, several lengths of plastic drainpipe, and multiple golf balls. Systolic and diastolic blood pressures but not heart rate or activity were higher in the double-housed rats than those housed alone. During the last period, the rats previously housed with another rat were switched to single housing, and those previously housed alone were placed with another rat. The daily activity and cage enrichments were otherwise continued. Removal of a cage mate increased systolic blood pressure, diastolic blood pressure, and heart rate but not activity compared parameters in animals that were changed from single to double housing. During the entire experiment, activity and all cardiovascular parameters were increased during the dark phase compared to the light phase of the daily photoperiod. However, there was no statistically significant correlation between these circadian changes and the housing conditions. In summary, providing social enrichment in the form of another rat or non-social cage enrichment combined with a daily period of group housing and physical activity increased diastolic and/or systolic blood pressure of SHR rats. In addition, the loss of continuous social enrichment increased blood pressure and heart rate even when the other enrichments were continued. These changes were not always related to increased activity in the cage.

Treatment of early seropositive rheumatoid arthritis with minocycline: four-year followup of a double-blind, placebo-controlled trial

OBJECTIVE

Rheumatoid arthritis (RA) causes substantial morbidity and mortality, and current treatments are suboptimal. Recent studies have demonstrated the short-term efficacy of minocycline in the treatment of patients with early RA. This study was undertaken to compare patients treated with conventional therapy in the early phase of their RA and those treated with minocycline, after 4 years of followup.

METHODS

Forty-six patients with seropositive RA of <1 year's duration had been enrolled in a double-blind study of minocycline (100 mg twice daily) versus placebo. After the blinded portion of the study (3-6 months, depending upon response), all patients were treated with conventional therapy. This report compares those patients randomized to receive placebo for 3 months and then conventional therapy for the duration of 4 years versus those originally randomized to receive minocycline.

RESULTS

Twenty of the 23 original minocycline-treated patients and 18 of the 23 original placebo-treated patients were available for followup (mean 4 years). At followup, RA was in remission (American College of Rheumatology criteria) without disease-modifying antirheumatic drug (DMARD) or steroid therapy in 8 of the patients originally treated with minocycline compared with 1 patient in the placebo group (P = 0.02). Ten patients in the minocycline group versus 16 in the original placebo group currently require DMARD therapy (P = 0.02).

CONCLUSION

Among patients with seropositive RA, remissions are more frequent and the need for DMARD therapy is less in those treated early in the disease course with minocycline compared with those treated with conventional therapy delayed by an average of only 3 months. Minocycline appears to be an effective therapy for early RA; further investigation into its mechanism of action is needed.

Using a Therapy Dog to Alleviate the Agitation and Desocialization of People With Alzheimer's Disease

1. Short-term exposure to a therapy dog can reduce the number of agitation behaviors in institutionalized persons with Alzheimer's disease (AD), particularly during the period of agitation known as sundown syndrome. 2. The presence of a therapy dog can increase socialization behaviors among a group of persons with AD. 3. A therapy dog can be used as an adjunct to other calming interventions for persons with AD.

Administration of an unconjugated bile acid increases duodenal tumors in a murine model of familial adenomatous polyposis

Intestinal carcinogenesis involves the successive accumulation of multiple genetic defects until cellular transformation to an invasive phenotype occurs. This process is modulated by many epigenetic factors. Unconjugated bile acids are tumor promoters whose presence in intestinal tissues is regulated by dietary factors. We studied the role of the unconjugated bile acid, chenodeoxycholate, in an animal model of familial adenomatous polyposis. Mice susceptible to intestinal tumors as a result of a germline mutation in Apc (Min/+ mice) were given a 10 week dietary treatment with 0.5% chenodeoxycholate. Following this, the mice were examined to determine tumor number, enterocyte proliferation, apoptosis and beta-catenin expression. Intestinal tissue prostaglandin E2 (PGE2) levels were also assessed. Administration of chenodeoxycholate in the diet increased duodenal tumor number in Min/+ mice. Promotion of duodenal tumor formation was accompanied by increased beta-catenin expression in duodenal cells, as well as increased PGE2 in duodenal tissue. These data suggest that unconjugated bile acids contribute to periampullary tumor formation in the setting of an Apc mutation.

Isolated subluxation of the extensor pollicis longus tendon. A cause of 'boutonnière' deformity of the thumb

Isolated ulnar subluxation of the extensor pollicis longus (EPL) tendon occurs when there is damage to the radial side of the extensor hood on the dorsum of the metacarpophalangeal joint of the thumb. The thumb collapses into a pseudoboutonnière deformity because the EPL tendon subluxes and comes to lie palmar to the centre of rotation of the metacarpophalangeal joint to act as a flexor instead of an extensor. The extensor pollicis brevis tendon which lies in a deeper plane to the EPL is unaffected. We describe four cases and propose conservative treatment as being effective in recent injuries.

Treatment of early rheumatoid arthritis with minocycline or placebo: results of a randomized, double-blind, placebo-controlled trial

OBJECTIVE

To determine if minocycline is an effective therapy for seropositive rheumatoid arthritis (RA) when used within the first year of disease.

METHODS

The Rheumatoid Arthritis Investigational Network enrolled 46 patients with RA of <1 year duration into a 6-month study of minocycline (100 mg twice daily) versus placebo. All patients were rheumatoid factor positive. The primary end point of the study was successful completion of 6 months of treatment with no drug toxicity while maintaining 50% improvement in composite symptoms of arthritis.

RESULTS

Eighteen of the 46 patients who were enrolled met 50% improvement criteria at 3 months, and maintained at least a 50% improvement for 6 months with no significant drug toxicity. Among them were 15 of the 23 patients (65%) treated with minocycline and 3 of 23 patients (13%) treated with placebo (P < 0.001).

CONCLUSION

In patients with early seropositive RA, therapy with minocycline is superior to placebo.

Regulation of thymus PCNA expression is altered in radiation-sensitive wasted mice

Mice bearing the autosomal recessive mutation 'wasted' (wst/wst) express a disease syndrome characterized by neurologic dysfunction, immunodeficiency, and increased sensitivity to the killing effects of ionizing radiation relative to normal littermates (wst/-) and to parental control mice (BCF1, BALB/c, and C57BL/6). Many of these abnormalities, evident as early as 21 days of age, have been localized to thymic tissues and T-lymphocyte populations. Comparison of two-dimensional gel electrophoresis patterns of proteins from wst/wst and control mouse thymus revealed that an acidic protein with a molecular mass of approximately 30 kDa was consistently expressed at lower levels in wasted mice than in controls. Microsequencing of this protein revealed a sequence of 19 N-terminal amino acids identical to the sequence of murine proliferating cell nuclear antigen (PCNA). Northern blot analyses of PCNA expression in thymus and spleen demonstrated lower accumulation of PCNA-specific transcripts in wasted mice compared with that in controls. Because PCNA expression is associated with cell cycle progression, the percentages of thymic and splenic cells in each stage of the cell cycle were examined; there were no differences in the cell stage distribution of lymphocytes freshly isolated from wasted mice compared with littermate or parental controls. After activation with concanavalin A, however, splenocytes from wst/wst mice showed a lower percentage of cells in S phase compared with that in controls. Southern blots with PCNA probes showed that the PCNA loci from the wasted mice and their normal littermates have the same restriction maps. While differences in polymerase chain reaction (PCR) priming were obtained, these could be attributed to strain-specific differences in mouse PCNA pseudogenes. These results suggest the presence of an alteration in the pathway leading to PCNA expression in radiation-sensitive tissues of wasted mice.

Matrix metalloproteinases and processing of pro-TNF-alpha

Tumor necrosis factor-alpha (TNF-alpha) is released from a cell membrane-anchored precursor by proteolytic cleavage. We have shown that broad spectrum synthetic inhibitors of matrix metalloproteinases (MMPs) prevent the processing of the TNF precursor but do not inhibit the release of other cytokines. Purified MMPs, stromelysin, matrilysin, collagenase, and the gelatinases can all cleave a recombinant pro-TNF substrate to yield mature TNF. MMP inhibitors prevent the rise in blood levels of TNF after endotoxin administration in rats and are effective in animal models of inflammatory disease such as adjuvant arthritis. Drugs that inhibit MMP action and TNF release show great promise for the treatment of autoimmune inflammatory diseases.

Processing of tumour necrosis factor-alpha precursor by metalloproteinases

Tumour necrosis factor-alpha (TNF-alpha) is a potent pro-inflammatory and immunomodulatory cytokine implicated in inflammatory conditions such as rheumatoid arthritis, Crohn's disease, multiple sclerosis and the cachexia associated with cancer or human immunodeficiency virus infection. TNF-alpha is initially expressed as a 233-amino-acid membrane-anchored precursor which is proteolytically processed to yield the mature, 157-amino-acid cytokine. The processing enzyme(s) which cleave TNF-alpha are unknown. Here we show that the release of mature TNF-alpha from leukocytes cultured in vitro is specifically prevented by synthetic hydroxamic acid-based metalloproteinase inhibitors, which also prevent the release of TNF-alpha into the circulation of endotoxin challenged rats. A recombinant, truncated TNF-alpha precursor is cleaved to biologically active, mature TNF-alpha by several matrix metalloproteinase enzymes. These results indicate that processing of the TNF-alpha precursor is dependent on at least one matrix metalloproteinase-like enzyme, inhibition of which represents a novel therapeutic mechanism for interfering with TNF-alpha production.

The non-operative management of radial head fractures: a randomized trial of three treatments

Ninety-eight consecutive patients with Mason type 1 and 2 radial head fractures were randomized into three treatment groups to compare early mobilization with immobilization in flexion and extension. Eighty-one patients were reviewed on average 25 months following fracture and assessed for pain, disability and range of movement. Loss of full extension was the most frequent restriction of movement and was found in 17 patients. Two patients had restricted flexion without limited extension. Patients immobilized in a flexion cast had a significantly reduced range of movement compared with patients immobilized in extension (P = 0.02). Nineteen patients had residual pain and again the flexion group fared worse than the extension group (P = 0.06). Results from early mobilization in a sling were not significantly different from the other two groups. Treatment of radial head fractures in flexion casts should be avoided.

SPECT Imaging in the Diagnosis of Meniscal Tears

Sixty patients scheduled for arthroscopy of a knee because of suspected meniscal tears had preoperative planar and single photon emission computed tomography (SPECT) radionuclide scans. A crescentic pattern of uptake on the SPECT transaxial view was used as a criterion for diagnosing a tear of a meniscus. The sensitivity of the investigation was 77%, specificity 74%, negative predictive value (NPV) 65%, positive predictive value (PPV) 83%, and accuracy 76%. Tears of the posterior horn of the cartilage were also associated with intense focal uptake on the transaxial view as well as increased equilibrium activity in the adjacent femoral condyle. When these appearances were included as additional criteria the sensitivity rose to 90%, NPV 81%, and accuracy 84%. This study confirms the usefulness of SPECT imaging in identifying meniscal tears.

Role of endothelium-derived nitric oxide in hemodynamic adaptations after graded renal mass reduction

The mediator(s) of the adaptive increases in renal blood flow (RBF) and glomerular filtration rate (GFR) after renal mass reduction have not been identified. The present studies were designed to investigate the role of endothelium-derived nitric oxide (EDNO) in the hemodynamic adaptations after graded renal mass reduction. The experiments were performed in rats that had undergone a sham reduction in renal mass, uninephrectomy (UNX), or 5/6 NX (UNX plus excision of both poles of the contralateral kidney) 3-4 wk before. Measurements of RBF, GFR, renal vascular resistance (RVR), mean arterial pressure (MAP), and plasma renin concentration (PRC) were obtained before and after administration of the EDNO synthesis inhibitor NG-monomethyl-L-arginine (L-NMMA). L-NMMA (50 mg/kg bolus plus 500 micrograms.kg-1.min-1 infusion) led to significant (P < 0.01) and comparable increases in MAP (mmHg) (P < 0.01) in sham rats (117 +/- 6 to 154 +/- 6), UNX rats (112 +/- 5 to 139 +/- 7), and 5/6 NX rats (116 +/- 5 to 149 +/- 7). RVR increased significantly in all three groups (P < 0.01). The resultant decrease in RBF (ml.min-1.kg-1) was similar in sham rats (34.9 +/- 2.6 to 23.8 +/- 1.6), UNX rats (43.9 +/- 3.6 to 27.3 +/- 2.8), and 5/6 NX rats (34.6 +/- 2 to 22.3 +/- 1.6) (P < 0.01 for all groups).(ABSTRACT TRUNCATED AT 250 WORDS)

Reversible compensatory hypertrophy in rat kidneys: morphometric characterization

Functional renal compensatory hypertrophy (RCH) in the uninephrectomized rat is completely reversible by transplantation in Brown Norway (BN) rats, while anatomic RCH is not. To determine the nephron element(s) responsible for persistent anatomic RCH, we performed morphometric analysis on perfusion fixed rat kidneys following renal function studies. In this model the function of renal transplants is not different from contralateral and unmanipulated control kidneys, and there is no histological evidence of rejection. Rats uninephrectomized for three or six weeks had larger glomeruli than controls, and after transplantation of a previously hypertrophied kidney into a rat with a normal or a solitary hypertrophied kidney, glomerular size returned to control levels. Increased glomerular capillary volume (CVCP) in kidneys with RCH was due to increased capillary length (LCP; 13.1 +/- 1.0 mm cf. 10.3 +/- 0.9, P < 0.01) without increase in capillary radius (RCP; 3.26 +/- 0.33 microM cf. 3.28 +/- 0.24). In contrast, return of CVCP to control levels in kidneys undergoing regression was associated with persistently elevated LCP (13.0 +2- 2.9 mm; native previously hypertrophied kidney; 12.2 +/- 0.9; transplanted previously hypertrophied kidney vs. 10.3 +/- 0.9, P < 0.01) and decreased RCP (2.79 +/- 0.10 microM and 2.73 +/- 0.09, cf 3.28 +/- 0.24, P < 0.01). RCH was associated with proportional increases in glomerular, tubular, and vascular-interstitial volumes while only elevated tubular volume persisted during regression. Altered glomerular capillary dimensions and increased tubular volumes acquired during renal RCH induced by unilateral nephrectomy persisted during complete functional regression.(ABSTRACT TRUNCATED AT 250 WORDS)

Streptozotocin-induced renal hemodynamic changes in isogenic Lewis rats: a kidney transplant study

Streptozotocin (STZ)-induced diabetes mellitus is associated with decreased renal clearances of inulin and p-aminohippurate (PAH). The present experiments were designed to determine whether STZ-induced renal hemodynamic changes are due to the drug per se, rather than to the diabetic state that it induces. Isogenic Lewis rats with native right and transplanted left kidneys were studied. In one group, kidney donors received 50 mg STZ/kg body wt on day 1 and transplantation was performed on day 4 (untreated recipients). On day 29, the inulin and PAH clearances of these nondiabetic recipients were, respectively, 0.94 +/- 0.04 and 2.58 +/- 0.11 ml.min-1 x g-1 for the transplanted left kidney (previously exposed to STZ) and 0.95 +/- 0.07 and 2.54 +/- 0.14 ml.min-1 x g-1 for the native right kidney (never exposed to STZ). In another group, recipients received STZ on day 1 and transplantation was performed on day 4 (untreated donors). On day 29, the inulin and PAH clearances of these diabetic recipients were, respectively, 0.62 +/- 0.04 and 1.46 +/- 0.11 ml.min-1 x g-1 for the transplanted left kidney (never exposed to STZ) and 0.61 +/- 0.05 and 1.42 +/- 0.08 ml.min-1 x g-1 for the native right kidney (previously exposed to STZ). We conclude that the diabetic state, rather than STZ, is responsible for the decreased renal clearances of inulin and PAH in this experimental model.

Reversible compensatory hypertrophy in transplanted brown Norway rat kidneys

Recently we described methods for optimizing the function of transplanted rat kidneys. In unilaterally nephrectomized recipients, one week after surgery, the left transplanted kidney was identical to the right native kidney with respect to wet weight and the clearances of inulin and para-aminohippuric acid (PAH). The goals of the present experiments were first, to extend the post-surgery period to three weeks (sufficient to allow hypertrophic changes), and second, to study function of transplanted hypertrophied kidneys. Genetically identical Brown Norway rats were used as donor and recipients. Three weeks after transplanting a normal kidney into a unilaterally-nephrectomized recipient, the transplanted kidney had a normal plasma flow and was identical to the contralateral native kidney with respect to wet weight and the clearances of inulin and PAH. Three weeks after transplanting a normal kidney into a bilaterally-nephrectomized recipient, the wet weight, inulin and PAH clearances, and plasma flow of the transplanted kidney were all higher than control, and not significantly different from those observed in unilaterally-nephrectomized control rats. Thus, transplanted and native kidneys exhibited the same degree of compensatory hypertrophy. Hypertrophied donor kidneys (that is, the donor rat had been unilaterally-nephrectomized three weeks previously) remained hypertrophied in bilaterally-nephrectomized recipients, but in unilaterally-nephrectomized recipients, they regressed towards normal (that is, the values of wet weight, inulin and PAH clearances and plasma flow were significantly less than those in rats with only one kidney) while the contralateral native kidney remained normal (values of wet weight and inulin and PAH clearances were not different from control).(ABSTRACT TRUNCATED AT 250 WORDS)

High osmolality-low pH flush solutions improve renal transplant function in rats

Although transplanting rat kidneys is an established microsurgical technique, inulin clearance is abnormally low, due to rejection and/or warm ischemia-induced damage. In the present studies, rejection was avoided by using inbred Brown Norway rats as donors and recipients. Donor kidneys were flushed with ice-cold solutions of various composition (saline, saline + 200 or 400 mM mannitol) and pHs (5.7, 6.4, and 7.4), and the kidneys were kept cold during transplantation into unilaterally nephrectomized recipients. Renal function was assessed by clearance techniques 1 week later. In control rats, with both native kidneys intact, the ratio of inulin clearance, left kidney to right kidney, was 0.99 +/- 0.02. In rats with a native right kidney and a transplanted left kidney that had been flushed with saline, the ratio was considerably lower (0.46 +/- 0.09). Adding 200 mM mannitol to the saline flush solution increased the ratio (0.89 +/- 0.09). In comparison, adding 200 mM mannitol and 5 mM phosphate buffer at pH 7.4 resulted in a somewhat lower ratio (0.80 +/- 0.09), whereas adding 200 mM mannitol and 5 mM phosphate buffer at pH 5.7 resulted in a higher ratio, one that was indistinguishable from control (0.97 +/- 0.09). Thus, in this latter group, the inulin clearances of the transplanted kidneys were identical to those of the contralateral native kidneys.

Anterolateral rupture of popliteal cysts in rheumatoid arthritis

Popliteal cysts occur commonly in both normal and arthritic knees. Most cysts are formed by distension of the medially situated semimembranosus bursa. Popliteus bursa distension occurs uncommonly as a lateral popliteal cyst. Two cases of rupture of lateral cysts which produced symptoms related to the anterolateral lower leg are reported. The difficulty of diagnosing the condition because of this unusual site of inflammation and subsequent management problems are discussed.

Kidney transplants in cyclosporine-treated Sprague-Dawley rats

Previous studies by others have shown that transplanted rat kidneys have abnormally low clearances of paraaminohippuric acid, inulin, and creatinine, due to rejection and/or to warm-ischemia-induced injury. In the present studies, randomly bred Sprague-Dawley rats were used as donors and recipients. The left kidneys of recipients were removed, and the right kidneys were left intact. Donor kidneys were flushed with an ice-cold hypertonic solution (150 mM NaCl, 200 mM mannitol, pH 6.4), and the kidneys were kept cold during surgery. Renal function was assessed 1 week later. The left transplanted kidneys in untreated recipients exhibited morphologic evidence of rejection, and the clearances of PAH and inulin were approximately 50% of those of the right native kidneys. CsA-treated rats did not reject the transplants, and the PAH and inulin clearances of the left transplanted kidneys were identical to those of the right native kidneys. Untreated and CsA-treated rats with both native kidneys intact served as controls. The amount of CsA given during the 7-day period produced no measurable change in renal function. This is the first demonstration of virtually normal hemodynamics in transplanted rat kidneys when randomly bred animals are used as donors and recipients. Moreover, the results indicate that if both rejection and warm ischemia are avoided, the presence of a functioning native kidney does not have a detrimental effect on the function of a transplanted kidney.