Hamman Syndrome with a Rare Feature of Pneumorrhachis - An Unusual Complication of Polysubstance abuse and e-vaping.

Hamman syndrome is defined as dissection of air in mediastinum and skin fascia usually due to increased intrathoracic pressure. The air leak tends to make its way into pleural and pericardial layers; however, in rare instances air can also dissect into epidural spaces, regarded as pneumorrhachis. We present a case of a young male with a history of polysubstance abuse and e-vaping, who presented with symptoms of altered mental status. Given the concerning physical examination, a computed tomography of the chest was undertaken, which showed pneumothorax, pneumomediastinum and pneumorrhachis. The patient was closely monitored in the intensive care unit and improved after symptomatic management. The symptoms of pneumorrhachis depend on the volume and location of air in intracranial and intraspinal space. Although asymptomatic in our case, it is crucial for clinicians to be aware that pneumorrhachis with Hamman syndrome can potentially cause neurological deficits and cardiopulmonary arrest in severe cases due to increased intraspinal and intracranial hypertension, emphasising the need for close monitoring. LEARNING POINTS: Elevated intrathoracic pressure generated by deep inhalation of an aerosolised product is one of the triggers of air dissection in pleural, pericardial, and mediastinal regions. In rare instances, air can also translocate into intracranial and intraspinal spaces, which is referred to as pneumorrhachis.Mostly asymptomatic, pneumorrhachis has the potential to develop acute neurological deficits due to increased intracranial and intraspinal pressure, validating the need for acute monitoring.Most cases of pneumorrhachis are managed conservatively. However, severe cases warrant decompression or high concentrations of oxygen administration to facilitate air absorption.

Expression deregulation of genes related to DNA repair and lead toxicity in occupationally exposed industrial workers.

OBJECTIVE: Globally millions of people working in various industries and are exposed to different toxins which may affect their genetic stability and DNA integrity. Present study was designed to estimate the expression variation of genes related to DNA repair (XRCC1, PARP1) and lead toxicity (ALAD) in exposed industrial workers. METHODS: About 200 blood samples were collected from workers of brick kiln, welding, furniture and paint industry (50/industry) along with age and gender matched controls. mRNA expression of genes was measured using RT-PCR. Serum levels of total ROS, POD, TBAR activity was calculated. Blood lead levels were estimated by atomic absorption spectrometer. RESULTS: Relative expression of XRCC1 and PARP1 gene was significantly (P < 0.001) upregulated, while ALAD gene expression was downregulated in exposed group compared to control. Expression of XRCC1 and PARP1 was increased (P < 0.001) in exposed workers with > 30 year age compared to control with > 30 year age. Same was observed when < 30 year age group of control and exposed was compared. Likewise, XRCC1 and PARP1 expression was increased (P < 0.001) in exposed workers with > 30 year age compared to workers with < 30 year age. Whereas, ALAD gene showed significant (P < 0.01) decrease in > 30 year age workers compared to control of same age and exposed with < 30 year of age. Relative expression of XRCC1 and PARP1 was increased (P < 0.001) in exposed smokers compared to exposed non-smokers and control smokers. Whereas, ALAD gene expression reduced (P < 0.001) significantly in both groups. Blood lead content was higher (P < 0.001) in exposed group compared to control. Strong correlation was observed between XRCC1, PARP1 and ALAD gene versus age, total exposure duration, exposure per day and lead deposition. ROS, TBARS and POD activity was higher (P < 0.01) in exposed group compared to control group. CONCLUSION: Present study suggested deregulation of genes related to DNA repair and lead intoxication in exposed group compared to controls. Strong correlation was observed between selected genes and demographic parameters. Present results revealed altered activity of oxidative stress markers which would induce oxidative damage to DNA integrity and limit the function of repair enzymes.

Tissue characterization of benign cardiac tumors by cardiac magnetic resonance imaging, a review of core imaging protocol and benign cardiac tumors.

Generally, cardiac masses are initially suspected on routine echocardiography. Cardiac magnetic resonance (CMR) imaging is further performed to differentiate tumors from pseudo-tumors and to characterize the cardiac masses based on their appearance on T1/T2-weighted images, detection of perfusion and demonstration of gadolinium-based contrast agent uptake on early and late gadolinium enhancement images. Further evaluation of cardiac masses by CMR is critical because unnecessary surgery can be avoided by better tissue characterization. Different cardiac tissues have different T1 and T2 relaxation times, principally owing to different internal biochemical environments surrounding the protons. In CMR, the signal intensity from a particular tissue depends on its T1 and T2 relaxation times and its proton density. CMR uses this principle to differentiate between various tissue types by weighting images based on their T1 or T2 relaxation times. Generally, tumor cells are larger, edematous, and have associated inflammatory reactions. Higher free water content of the neoplastic cells and other changes in tissue composition lead to prolonged T1/T2 relaxation times and thus an inherent contrast between tumors and normal tissue exists. Overall, these biochemical changes create an environment where different cardiac masses produce different signal intensity on their T1- weighted and T2- weighted images that help to discriminate between them. In this review article, we have provided a detailed description of the core CMR imaging protocol for evaluation of cardiac masses. We have also discussed the basic features of benign cardiac tumors as well as the role of CMR in evaluation and further tissue characterization of these tumors.

Glucagon-like peptide-1: a multi-faceted anti-inflammatory agent.

Inflammation contributes to many chronic conditions. It is often associated with circulating pro-inflammatory cytokines and immune cells. GLP-1 levels correlate with disease severity. They are often elevated and can serve as markers of inflammation. Previous studies have shown that oxytocin, hCG, ghrelin, alpha-MSH and ACTH have receptor-mediated anti-inflammatory properties that can rescue cells from damage and death. These peptides have been studied well in the past century. In contrast, GLP-1 and its anti-inflammatory properties have been recognized only recently. GLP-1 has been proven to be a useful adjuvant therapy in type-2 diabetes mellitus, metabolic syndrome, and hyperglycemia. It also lowers HbA1C and protects cells of the cardiovascular and nervous systems by reducing inflammation and apoptosis. In this review we have explored the link between GLP-1, inflammation, and sepsis.

Incidence of Microalbuminuria and Factors Affecting It in Patients With Type 2 Diabetes Mellitus.

Background and objectives Microalbuminuria prevalence is high in patients with type 2 diabetes mellitus (T2DM) all over the world and its prevalence is affected by several factors. In Pakistan, microalbuminuria and factors that play a role in its development in patients with T2DM are under-researched. This study aimed to determine the incidence of microalbuminuria and the factors affecting it in patients with T2DM. Material and methods This descriptive cross-sectional study was performed on 129 diagnosed patients with T2DM in the outpatient department of Benazir Bhutto Hospital, Rawalpindi, for approximately six months from August 2021 to January 2022. Patients were recruited in the study through a non-probability consecutive sampling technique and established inclusion and exclusion criteria. Ethical approval was obtained from the relevant hospital ethical review board (ERB). After explaining the study's aims, informed consent was also taken from all patients before the start of data collection. A self-structured and interview-based questionnaire was used for the collection of data. Descriptive statistics and a chi-square test were applied for the data analysis using Statistical Package for the Social Sciences (SPSS) version 25 (Armonk, NY: IBM Corp.). Results The incidence of microalbuminuria in the study population was 31.78%. The association between microalbuminuria and age (p = 0.002), gender (p = 0.003), duration of diabetes mellitus (p = 0.001), therapy type (p = 0.03), control of diabetes mellitus, (p = 0.001), and hypertension (p = 0.002) was statistically significant. Higher age group, male gender, longer duration of diabetes mellitus, oral hypoglycemic agents, poorly controlled diabetes mellitus, and history of hypertension, all were found to raise the incidence of microalbuminuria. Even though being overweight was also found to raise the incidence of microalbuminuria, the association between microalbuminuria and nutritional status was statistically insignificant (p = 0.05). Conclusion Microalbuminuria incidence is significantly high in the study population. The factors such as increasing age, male gender, longer duration of the diabetes mellitus, oral hypoglycemic agents, poorly controlled diabetes mellitus, and history of hypertension, all raise the incidence of microalbuminuria in patients with T2DM to a statistically significant extent. Screening of microalbuminuria patients with T2DM should be added to the routine investigations for diabetes mellitus for the early detection of renal and cardiovascular complications.

Risk Factors of Nephrolithiasis in a Tertiary Care Hospital in Rawalpindi: A Descriptive Cross-Sectional Study.

Background Nephrolithiasis (renal stones) is the most common urological disease. Its prevalence is high in every part of the world. Several factors lead to renal stone formation. In Pakistan, nephrolithiasis prevalence is also high as Pakistan is located in a region which is known as the salt belt. However, nephrolithiasis and its possible risk factors are under-researched in Pakistan. Objective This study aims to identify the risk factors for nephrolithiasis among admitted patients with renal stones. This may lead to a reduction in renal stone incidence and its allied complications by the prevention of risk factors that would have a major role in renal stone formation. Material and methods This descriptive cross-sectional study was performed among the 143 admitted patients with renal stones in the urology ward of Benazir Bhutto Hospital, Rawalpindi, for approximately six months from November 2021 to April 2022. Non-probability convenient sampling and developed inclusion and exclusion criteria were used for the recruitment of patients. After elaborating on the objectives, the study data were collected by interviewers through a self-structured questionnaire. Descriptive analysis was carried out using SPSS version 25.0 (IBM Corp., Armonk, NY). Results Nephrolithiasis was more prevalent among patients who had an age group range of 15-30 years (47.55%), male gender (56.65%), illiterate educational status (53.14%), lower socioeconomic status (66.43%), inadequate intake of water (61.53%), used tap water (56.64%), a habit of daily vegetable intake (65.04%), sedentary lifestyle (51.74%), family history of renal stones (57.34%), no diabetes mellitus (62.94%), no hypertension (52.45%), and overweight (48.23%). Conclusion In brief, the age group of 15-30 years, male gender, illiteracy, lower socioeconomic status, insufficient water intake, tap water, high vegetables, inactive lifestyle, family history of nephrolithiasis, and a high BMI all increase the risk of nephrolithiasis.

Select gp120 V2 domain specific antibodies derived from HIV and SIV infection and vaccination inhibit gp120 binding to α4ß7.

The GI tract is preferentially targeted during acute/early HIV-1 infection. Consequent damage to the gut plays a central role in HIV pathogenesis. The basis for preferential targeting of gut tissues is not well defined. Recombinant proteins and synthetic peptides derived from HIV and SIV gp120 bind directly to integrin α4ß7, a gut-homing receptor. Using both cell-surface expressed α4ß7 and a soluble α4ß7 heterodimer we demonstrate that its specific affinity for gp120 is similar to its affinity for MAdCAM (its natural ligand). The gp120 V2 domain preferentially engages extended forms of α4ß7 in a cation -sensitive manner and is inhibited by soluble MAdCAM. Thus, V2 mimics MAdCAM in the way that it binds to α4ß7, providing HIV a potential mechanism to discriminate between functionally distinct subsets of lymphocytes, including those with gut-homing potential. Furthermore, α4ß7 antagonists developed for the treatment of inflammatory bowel diseases, block V2 binding to α4ß7. A 15-amino acid V2 -derived peptide is sufficient to mediate binding to α4ß7. It includes the canonical LDV/I α4ß7 binding site, a cryptic epitope that lies 7-9 amino acids amino terminal to the LDV/I, and residues K169 and I181. These two residues were identified in a sieve analysis of the RV144 vaccine trial as sites of vaccine -mediated immune pressure. HIV and SIV V2 mAbs elicited by both vaccination and infection that recognize this peptide block V2-α4ß7 interactions. These mAbs recognize conformations absent from the ß- barrel presented in a stabilized HIV SOSIP gp120/41 trimer. The mimicry of MAdCAM-α4ß7 interactions by V2 may influence early events in HIV infection, particularly the rapid seeding of gut tissues, and supports the view that HIV replication in gut tissue is a central feature of HIV pathogenesis.

MAdCAM costimulation through Integrin-α4ß7 promotes HIV replication.

Human gut-associated lymphoid tissues (GALT) play a key role in the acute phase of HIV infection. The propensity of HIV to replicate in these tissues, however, is not fully understood. Access and migration of naive and memory CD4+ T cells to these sites is mediated by interactions between integrin α4ß7, expressed on CD4+ T cells, and MAdCAM, expressed on high endothelial venules. We report here that MAdCAM delivers a potent costimulatory signal to naive and memory CD4+ T cells following ligation with α4ß7. Such costimulation promotes high levels of HIV replication. An anti-α4ß7 mAb that prevents mucosal transmission of SIV blocks MAdCAM signaling through α4ß7 and MAdCAM-dependent viral replication. MAdCAM costimulation of memory CD4+ T cells is sufficient to drive cellular proliferation and the upregulation of CCR5, while naive CD4+ T cells require both MAdCAM and retinoic acid to achieve the same response. The pairing of MAdCAM and retinoic acid is unique to the GALT, leading us to propose that HIV replication in these sites is facilitated by MAdCAM-α4ß7 interactions. Moreover, complete inhibition of MAdCAM signaling by an anti-α4ß7 mAb, an analog of the clinically approved therapeutic vedolizumab, highlights the potential of such agents to control acute HIV infection.

Signal peptide of HIV envelope protein impacts glycosylation and antigenicity of gp120.

The HIV-1 envelope protein (Env) of early-replicating viruses encodes several distinct transmission signatures. One such signature involves a reduced number of potential N-linked glycosylation sites (PNGs). This transmission signature underscores the importance of posttranslational modifications in the fitness of early-replicating isolates. An additional signature in Env involves the overrepresentation of basic amino acid residues at a specific position in the Env signal peptide (SP). In this report, we investigated the potential impact of this SP signature on gp120 glycosylation and antigenicity. Two recombinant gp120s were constructed, one derived from an isolate that lacks this signature and a second from an early-replicating isolate that includes this signature. Chimeric gp120s were also constructed in which the two SPs were swapped between the isolates. All four gp120s were probed with glycan-, structure- and receptor- specific probes in a surface plasmon resonance binding assay. We found that the SP of Env influences qualitative aspects of Env glycosylation that in turn affect the antigenicity of Env in a major way. The SP impacts the affinity of Env for DC-SIGN, a lectin receptor expressed on dendritic cells that is believed to play a role in mucosal transmission. Additionally, affinity for the monoclonal antibodies 17b and A32, which recognize a CD4-induced, open conformation of Env is also altered. These results demonstrate that natural variation in the SP of HIV Env can significantly impact the antigenicity of mature gp120. Thus, the SP is likely subject to antibody-mediated immune pressure.

The Role of Integrin α4ß7 in HIV Pathogenesis and Treatment.

PURPOSE OF REVIEW: Acute HIV infection is characterized by high-level viral replication throughout the body's lymphoid system, particularly in gut-associated lymphoid tissues resulting in damage to structural components of gut tissue. This damage is irreversible and believed to contribute to the development of immune deficiencies. Antiretroviral therapy (ART) does not restore gut structure and function. Studies in macaques point to an alternative treatment strategy that may ameliorate gut damage. Integrin α4ß7 mediates the homing of lymphocytes to gut tissues. Vedolizumab, a monoclonal antibody (mAb) antagonist of α4ß7, has demonstrated efficacy and has been approved for the treatment of inflammatory bowel disease in humans. Here, we describe our current knowledge, and the gaps in our understanding, of the role of α4ß7 in HIV pathogenesis and treatment. RECENT FINDINGS: When administered to macaques prior to infection, a nonhuman primate analogue of vedolizumab prevents transmission of SIV. In combination with ART, this mAb facilitates durable virologic control following treatment interruption. Targeting α4ß7 represents a novel therapeutic approach to prevent and treat HIV infection.

Integrin α4ß7 expression on peripheral blood CD4+ T cells predicts HIV acquisition and disease progression outcomes.

The gastrointestinal (GI) mucosa is central to HIV pathogenesis, and the integrin α4ß7 promotes the homing of immune cells to this site, including those that serve as viral targets. Data from simian immunodeficiency virus (SIV) animal models suggest that α4ß7 blockade provides prophylactic and therapeutic benefits. We show that pre-HIV infection frequencies of α4ß7+ peripheral blood CD4+ T cells, independent of other T cell phenotypes and genital inflammation, were associated with increased rates of HIV acquisition in South African women. A similar acquisition effect was observed in a Kenyan cohort and in nonhuman primates (NHPs) after intravaginal SIV challenge. This association was stronger when infection was caused by HIV strains containing V2 envelope motifs with a preference for α4ß7 binding. In addition, pre-HIV α4ß7+ CD4+ T cells predicted a higher set-point viral load and a greater than twofold increased rate of CD4+ T cell decline. These results were confirmed in SIV-infected NHPs. Increased frequencies of pre-HIV α4ß7+ CD4+ T cells were also associated with higher postinfection expression of lipopolysaccharide binding protein, a microbial translocation marker, suggestive of more extensive gut damage. CD4+ T cells expressing α4ß7 were rapidly depleted very early in HIV infection, particularly from the GI mucosa, and were not restored by early antiretroviral therapy. This study provides a link between α4ß7 expression and HIV clinical outcomes in humans, in line with observations made in NHPs. Given the availability of a clinically approved anti-α4ß7 monoclonal antibody for treatment of inflammatory bowel disease, these data support further evaluation of targeting α4ß7 integrin as a clinical intervention during HIV infection.

HIV-1 gp120: A Target for Therapeutics and Vaccine Design.

Although extraordinary progress has been made in the treatment and prevention of HIV infection, the AIDS pandemic continues to rage globally with 2.1 million infections and 1.6 million AIDS-related deaths reported in 2013. Until an effective vaccine is developed, new strategies for treatment and prevention are needed. Regarding the prevention of HIV infection, a major focus of prevention research in general and vaccine research in particular involves the interaction of the HIV-1 envelope protein gp120 with cell-surface receptors, with the hope that a greater understanding of these interactions will lead to the development of novel strategies aimed at preventing and even treating HIV-1 infection. Particular attention has been directed toward gaining a more precise understanding of the early events in transmission focusing on that critical window of time when HIV first establishes infection in the host. Here we describe some of the recent findings involving HIV-1 envelope interactions with cell surface receptors that are relevant to transmission and which may represent new opportunities to develop strategies to prevent HIV infection.

Fluorescent protein-tagged Vpr dissociates from HIV-1 core after viral fusion and rapidly enters the cell nucleus.

BACKGROUND: HIV-1 Vpr is recruited into virions during assembly and appears to remain associated with the viral core after the reverse transcription and uncoating steps of entry. This feature has prompted the use of fluorescently labeled Vpr to visualize viral particles and to follow trafficking of post-fusion HIV-1 cores in the cytoplasm. RESULTS: Here, we tracked single pseudovirus entry and fusion and observed that fluorescently tagged Vpr gradually dissociates from post-fusion viral cores over the course of several minutes and accumulates in the nucleus. Kinetics measurements showed that fluorescent Vpr released from the cores very rapidly entered the cell nucleus. More than 10,000 Vpr molecules can be delivered into the cell nucleus within 45 min of infection by HIV-1 particles pseudotyped with the avian sarcoma and leukosis virus envelope glycoprotein. The fraction of Vpr from cell-bound viruses that accumulated in the nucleus was proportional to the extent of virus-cell fusion and was fully blocked by viral fusion inhibitors. Entry of virus-derived Vpr into the nucleus occurred independently of envelope glycoproteins or target cells. Fluorescence correlation spectroscopy revealed two forms of nuclear Vpr-monomers and very large complexes, likely involving host factors. The kinetics of viral Vpr entering the nucleus after fusion was not affected by point mutations in the capsid protein that alter the stability of the viral core. CONCLUSIONS: The independence of Vpr shedding of capsid stability and its relatively rapid dissociation from post-fusion cores suggest that this process may precede capsid uncoating, which appears to occur on a slower time scale. Our results thus demonstrate that a bulk of fluorescently labeled Vpr incorporated into HIV-1 particles is released shortly after fusion. Future studies will address the question whether the quick and efficient nuclear delivery of Vpr derived from incoming viruses can regulate subsequent steps of HIV-1 infection.

Targeting α4ß7 integrin reduces mucosal transmission of simian immunodeficiency virus and protects gut-associated lymphoid tissue from infection.

α4ß7 integrin-expressing CD4(+) T cells preferentially traffic to gut-associated lymphoid tissue (GALT) and have a key role in HIV and simian immunodeficiency virus (SIV) pathogenesis. We show here that the administration of an anti-α4ß7 monoclonal antibody just prior to and during acute infection protects rhesus macaques from transmission following repeated low-dose intravaginal challenges with SIVmac251. In treated animals that became infected, the GALT was significantly protected from infection and CD4(+) T cell numbers were maintained in both the blood and the GALT. Thus, targeting α4ß7 reduces mucosal transmission of SIV in macaques.

The HIV-1 envelope protein gp120 impairs B cell proliferation by inducing TGF-ß1 production and FcRL4 expression.

The humoral immune response after acute infection with HIV-1 is delayed and ineffective. The HIV-1 envelope protein gp120 binds to and signals through integrin α4ß7 on T cells. We found that gp120 also bound to and signaled through α4ß7 on naive B cells, which resulted in an abortive proliferative response. In primary B cells, signaling by gp120 through α4ß7 resulted in increased expression of the immunosuppressive cytokine TGF-ß1 and FcRL4, an inhibitory receptor expressed on B cells. Coculture of B cells with HIV-1-infected autologous CD4(+) T cells also increased the expression of FcRL4 by B cells. Our findings indicated that in addition to mediating chronic activation of the immune system, viral proteins contributed directly to HIV-1-associated B cell dysfunction. Our studies identify a mechanism whereby the virus may subvert the early HIV-1-specific humoral immune response.

Preferential HIV infection of CCR6+ Th17 cells is associated with higher levels of virus receptor expression and lack of CCR5 ligands.

Th17 cells are enriched in the gut mucosa and play a critical role in maintenance of the mucosal barrier and host defense against extracellular bacteria and fungal infections. During chronic human immunodeficiency virus (HIV) infection, Th17 cells were more depleted compared to Th1 cells, even when the patients had low or undetectable viremia. To investigate the differential effects of HIV infection on Th17 and Th1 cells, a culture system was used in which CCR6(+) CD4(+) T cells were sorted from healthy human peripheral blood and activated in the presence of interleukin 1ß (IL-1ß) and IL-23 to drive expansion of Th17 cells while maintaining Th1 cells. HIV infection of these cultures had minimal effects on Th1 cells but caused depletion of Th17 cells. Th17 loss correlated with greater levels of virus-infected cells and cell death. In identifying cellular factors contributing to higher susceptibility of Th17 cells to HIV, we compared Th17-enriched CCR6(+) and Th17-depleted CCR6(-) CD4 T cell cultures and noted that Th17-enriched CCR6(+) cells expressed higher levels of α4ß7 and bound HIV envelope in an α4ß7-dependent manner. The cells also had greater expression of CD4 and CXCR4, but not CCR5, than CCR6(-) cells. Moreover, unlike Th1 cells, Th17 cells produced little CCR5 ligand, and transfection with one of the CCR5 ligands, MIP-1ß (CCL4), increased their resistance against HIV. These results indicate that features unique to Th17 cells, including higher expression of HIV receptors and lack of autocrine CCR5 ligands, are associated with enhanced permissiveness of these cells to HIV.

The genotype of early-transmitting HIV gp120s promotes α (4) ß(7)-reactivity, revealing α (4) ß(7) +/CD4+ T cells as key targets in mucosal transmission.

Mucosal transmission of HIV is inefficient. The virus must breach physical barriers before it infects mucosal CD4+ T cells. Low-level viral replication occurs initially in mucosal CD4+ T cells, but within days high-level replication occurs in Peyer's patches, the gut lamina propria and mesenteric lymph nodes. Understanding the early events in HIV transmission may provide valuable information relevant to the development of an HIV vaccine. The viral quasispecies in a donor contracts through a genetic bottleneck in the recipient, such that, in low-risk settings, infection is frequently established by a single founder virus. Early-transmitting viruses in subtypes A and C mucosal transmission tend to encode gp120s with reduced numbers of N-linked glycosylation sites at specific positions throughout the V1-V4 domains, relative to typical chronically replicating isolates in the donor quasispecies. The transmission advantage gained by the absence of these N-linked glycosylation sites is unknown. Using primary α4ß7/CD4+ T cells and a flow-cytometry based steady-state binding assay we show that the removal of transmission-associated N-linked glycosylation sites results in large increases in the specific reactivity of gp120 for integrin-α4ß7. High-affinity for integrin α4ß7, although not found in many gp120s, was observed in early-transmitting gp120s that we analyzed. Increased α4ß7 affinity is mediated by sequences encoded in gp120 V1/V2. α4ß7-reactivity was also influenced by N-linked glycosylation sites located in C3/V4. These results suggest that the genetic bottleneck that occurs after transmission may frequently involve a relative requirement for the productive infection of α4ß7+/CD4+ T cells. Early-transmitting gp120s were further distinguished by their dependence on avidity-effects to interact with CD4, suggesting that these gp120s bear unusual structural features not present in many well-characterized gp120s derived from chronically replicating viruses. Understanding the structural features that characterize early-transmitting gp120s may aid in the design of an effective gp120-based subunit vaccine.

Selection of parasites with diminished drug susceptibility by amodiaquine-containing antimalarial regimens in Uganda.

BACKGROUND: Amodiaquine (AQ) is paired with artesunate (AS) or sulfadoxine-pyrimethamine (SP) in recommended antimalarial regimens. It is unclear how readily AQ resistance will be selected with combination chemotherapy. METHODS: We collected 61 Plasmodium falciparum samples from a cohort of Ugandan children randomized for treatment with AQ-SP, AS-AQ, or artemether-lumefantrine (AL) for uncomplicated malaria. In vitro susceptibility to monodesethylamodiaquine (MDAQ) was measured with a histidine-rich protein 2-based enzyme-linked immunosorbent assay, and potential resistance-mediating polymorphisms in pfmdr1 were evaluated. RESULTS: Parasites collected from patients treated with AQ-SP or AS-AQ within the prior 12 weeks were less susceptible to MDAQ (n = 18; mean of the median inhibitory concentration [IC(50)], 62.9 nmol/L; range, 12.7-158.3 nmol/L) than were parasites from those not treated within 12 weeks (n = 43; mean IC(50), 37.5 nmol/L; range, 6.3-184.7 nmol/L; P=.009) or only from those patients in the treatment arm that did not receive AQ (n = 12; mean IC(50), 28.8 nmol/L; range, 6.3-121.8 nmol/L; P = .004). The proportion of strains with polymorphisms expected to mediate diminished response to AQ (pfmdr1 86Y and 1246Y) increased after AQ therapy, although differences were not statistically significant. CONCLUSIONS: Prior therapy selected for diminished response to MDAQ, which suggests that AQ-containing regimens may rapidly lose efficacy in Africa. The mechanism of diminished MDAQ response is not fully explained by known mutations in pfmdr1.

Erythrocyte binding protein PfRH5 polymorphisms determine species-specific pathways of Plasmodium falciparum invasion.

Some human malaria Plasmodium falciparum parasites, but not others, also cause disease in Aotus monkeys. To identify the basis for this variation, we crossed two clones that differ in Aotus nancymaae virulence and mapped inherited traits of infectivity to erythrocyte invasion by linkage analysis. A major pathway of invasion was linked to polymorphisms in a putative erythrocyte binding protein, PfRH5, found in the apical region of merozoites. Polymorphisms of PfRH5 from the A. nancymaae-virulent parent transformed the nonvirulent parent to a virulent parasite. Conversely, replacements that removed these polymorphisms from PfRH5 converted a virulent progeny clone to a nonvirulent parasite. Further, a proteolytic fragment of PfRH5 from the infective parasites bound to A. nancymaae erythrocytes. Our results also suggest that PfRH5 is a parasite ligand for human infection, and that amino acid substitutions can cause its binding domain to recognize different human erythrocyte surface receptors.

Prognostic significance of overexpression and phosphorylation of epidermal growth factor receptor (EGFR) and the presence of truncated EGFRvIII in locoregionally advanced breast cancer.

PURPOSE: The prognostic value of the epidermal growth factor receptor (EGFR) in breast cancer and more specifically, in patients with locoregionally advanced disease, is still undefined. We hypothesized that EGFR status plays a major prognostic role in this setting, through expression, activation, or the presence of its mutated variant EGFRvIII. PATIENTS AND METHODS: We reviewed tumor samples of 225 patients treated uniformly in prospective trials of high-dose chemotherapy for four to nine positive axillary nodes, > or = 10 positive nodes, or inflammatory carcinoma, and observed for a median of 9 years (range, 3 to 13 years). We analyzed the effect on outcome of expression of EGFR, phosphorylated EGFR (phospho-EGFR), and EGFRvIII, as studied by immunohistochemistry. RESULTS: EGFR expression, phospho-EGFR, and mutated EGFRvIII were detected in 43%, 54%, and 4% of the patients, respectively. EGFR expression correlated with negative hormone receptor status, and was associated with significantly worse relapse-free survival (59% v 79%; P < .001) and overall survival (61% v 81%; P = .001) than no expression. There was no association of phospho-EGFR or EGFRvIII with outcome. Multivariate models confirmed the prognostic effect of EGFR independent of other known prognostic variables in this population. The prognostic value of EGFR was most prominent in the human epidermal growth factor receptor 2 (HER-2) -positive and the estrogen receptor/progesterone receptor-negative subgroups. CONCLUSION: EGFR expression, but not phospho-EGFR or EGFRvIII expression, is an independent adverse prognostic factor in patients with high-risk primary breast cancer, particularly when it is coexpressed with HER-2. Our results suggest the potential benefit of dual EGFR/HER-2 receptor targeting in this setting.