Efficacy and Safety of Ensovibep for Adults Hospitalized With COVID-19 : A Randomized Controlled Trial

BACKGROUND

Ensovibep (MP0420) is a designed ankyrin repeat protein, a novel class of engineered proteins, under investigation as a treatment of SARS-CoV-2 infection.

OBJECTIVE

To investigate if ensovibep, in addition to remdesivir and other standard care, improves clinical outcomes among patients hospitalized with COVID-19 compared with standard care alone.

DESIGN

Double-blind, randomized, placebo-controlled, clinical trial. (ClinicalTrials.gov: NCT04501978).

SETTING

Multinational, multicenter trial.

PARTICIPANTS

Adults hospitalized with COVID-19.

INTERVENTION

Intravenous ensovibep, 600 mg, or placebo.

MEASUREMENTS

Ensovibep was assessed for early futility on the basis of pulmonary ordinal scores at day 5. The primary outcome was time to sustained recovery through day 90, defined as 14 consecutive days at home or place of usual residence after hospital discharge. A composite safety outcome that included death, serious adverse events, end-organ disease, and serious infections was assessed through day 90.

RESULTS

An independent data and safety monitoring board recommended that enrollment be halted for early futility after 485 patients were randomly assigned and received an infusion of ensovibep (n = 247) or placebo (n = 238). The odds ratio (OR) for a more favorable pulmonary outcome in the ensovibep (vs. placebo) group at day 5 was 0.93 (95% CI, 0.67 to 1.30; P = 0.68; OR > 1 would favor ensovibep). The 90-day cumulative incidence of sustained recovery was 82% for ensovibep and 80% for placebo (subhazard ratio [sHR], 1.06 [CI, 0.88 to 1.28]; sHR > 1 would favor ensovibep). The primary composite safety outcome at day 90 occurred in 78 ensovibep participants (32%) and 70 placebo participants (29%) (HR, 1.07 [CI, 0.77 to 1.47]; HR < 1 would favor ensovibep).

LIMITATION

The trial was prematurely stopped because of futility, limiting power for the primary outcome.

CONCLUSION

Compared with placebo, ensovibep did not improve clinical outcomes for hospitalized participants with COVID-19 receiving standard care, including remdesivir; no safety concerns were identified.

PRIMARY FUNDING SOURCE

National Institutes of Health.

Effect of Oral Oseltamivir on Virological Outcomes in Low-risk Adults With Influenza: A Randomized Clinical Trial

BACKGROUND

Duration of viral shedding is a determinant of infectivity and transmissibility, but few data exist about oseltamivir's ability to alter viral shedding.

METHODS

From January 2012 through October 2017, a randomized, double-blinded multicenter clinical trial was conducted in adults aged 18-64 years at 42 sites in Thailand, the United States, and Argentina. Participants with influenza A or B and without risk factors for complications of influenza were screened for the study. Eligible participants were randomized to receive oseltamivir 75 mg or placebo twice daily for 5 days. The primary endpoint was the percentage of participants with virus detectable by polymerase chain reaction in nasopharyngeal swab at day 3.

RESULTS

Of 716 adults screened for the study, 558 were randomized, and 501 were confirmed to have influenza. Forty-six participants in the pilot study were excluded, and 449 of the 455 participants in the population for the primary analysis had day 3 viral shedding results. Ninety-nine (45.0%) of 220 participants in the oseltamivir arm had virus detected at day 3 compared with 131 (57.2%) of 229 participants in the placebo arm (absolute difference of -12.2% [-21.4%, -3.0%], P =; .010). The median time to alleviation of symptoms was 79.0 hours for the oseltamivir arm and 84.0 hours for the placebo arm (P =; .34) in those with confirmed influenza infection.

CONCLUSIONS

Oseltamivir decreased viral shedding in this low-risk population. However, in the population enrolled in this study, it did not significantly decrease the time to resolution of clinical symptoms.

CLINICAL TRIALS REGISTRATION

NCT01314911.

Anti-influenza immune plasma for the treatment of patients with severe influenza A: a randomised, double-blind, phase 3 trial

BACKGROUND

Infection with influenza virus causes substantial morbidity and mortality globally, although antiviral treatments are available. Previous studies have suggested that anti-influenza immune plasma could be beneficial as treatment, but they were not designed as randomised, blinded, placebo-controlled trials. Therefore, we aimed to prospectively evaluate the clinical efficacy of high-titre immune plasma compared with standard low-titre plasma to improve outcomes in patients with severe influenza A infection.

METHODS

We did this randomised, double-blind, phase 3 trial at 41 US medical centres to assess the efficacy of high-titre anti-influenza plasma (haemagglutination inhibition antibody titre ≥1:80) compared with low-titre plasma (≤1:10). Children and adults with PCR-confirmed influenza A infection, a National Early Warning score of 3 or greater, and onset of illness within 6 days before randomisation were eligible. Patients were randomly assigned (2:1) using an interactive web response system to receive either two units (or paediatric equivalent) of high-titre plasma (high-titre group) or low-titre plasma (low-titre group), and were followed up for 28 days from randomisation. High-titre and low-titre plasma had the same appearance. Randomisation was stratified by severity (in intensive care unit, not in intensive care but requiring supplemental oxygen, or not in intensive care and not requiring supplemental oxygen) and age (<18 years and ≥18 years). All participants, site staff, and the study team were masked to treatment allocation until after the final database lock. The primary endpoint was clinical status assessed by a six-point ordinal scale on day 7 (death, in intensive care, hospitalised but requiring supplemental oxygen, hospitalised not requiring supplemental oxygen, discharged but unable to resume normal activities, and discharged with full resumption of normal activities) analysed in a proportional odds model (an odds ratio [OR] >1 indicates improvement in clinical status across all categories for the high-titre vs the low-titre group). The primary analysis was done in the intention-to-treat population, excluding two participants who did not receive plasma. This trial is registered with ClinicalTrials.gov, NCT02572817.

FINDINGS

Participants were recruited between Jan 26, 2016, and April 19, 2018. Of 200 participants enrolled (177 adults and 23 children), 140 met the criteria for randomisation and were assigned to the high-titre group (n=92) or to the control low-titre group (n=48). One participant from each group did not receive plasma. At baseline, 60 (43%) of 138 participants were in intensive care and 55 (71%) of 78 participants who were not in intensive care required oxygen. 93% of planned plasma infusions were completed. The study was terminated in July, 2018, when independent efficacy analysis showed low conditional power to detect an effect of high-titre plasma even if full accrual (150 participants) was achieved. The proportional OR for improved clinical status on day 7 was 1·22 (95% CI 0·65-2·29, p=0·54). 47 (34%) of 138 participants experienced 88 serious adverse events: 32 (35%) with 60 events in the high-titre group and 15 (32%) with 28 events in the low-titre group. The most common serious adverse events were acute respiratory distress syndrome (ARDS; four [4%] vs two [4%]), allergic transfusion reactions (two [2%] vs two [4%]), and respiratory distress (three [3%] vs none). 65 (47%) participants experienced 183 adverse events: 42 (46%) with 126 events in the high-titre group and 23 (49%) with 57 events in the low-titre group. The most common adverse events were anaemia (four [3%] vs two [4%]) and ARDS (four [3%] vs three [5%]). Ten patients died during the study (six [7%] in the high-titre group vs four [9%] in the low-titre group, p=0·73). The most common cause of death was worsening of acute respiratory distress syndrome (two [2%] vs two [4%] patients).

INTERPRETATION

High-titre anti-influenza plasma conferred no significant benefit over non-immune plasma. Although our study did not have the precision to rule out a small, clinically relevant effect, the benefit is insufficient to justify the use of immune plasma for treating patients with severe influenza A.

FUNDING

National Institute of Allergy and Infectious Diseases of the National Institutes of Health (Bethesda, MD, USA).

Oseltamivir, amantadine, and ribavirin combination antiviral therapy versus oseltamivir monotherapy for the treatment of influenza: a multicentre, double-blind, randomised phase 2 trial

BACKGROUND

Influenza continues to have a substantial socioeconomic and health impact despite a long established vaccination programme and approved antivirals. Preclinical data suggest that combining antivirals might be more effective than administering oseltamivir alone in the treatment of influenza.

METHODS

We did a randomised, double-blind, multicentre phase 2 trial of a combination of oseltamivir, amantadine, and ribavirin versus oseltamivir monotherapy with matching placebo for the treatment of influenza in 50 sites, consisting of academic medical centre clinics, emergency rooms, and private physician offices in the USA, Thailand, Mexico, Argentina, and Australia. Participants who were aged at least 18 years with influenza and were at increased risk of complications were randomly assigned (1:1) by an online computer-generated randomisation system to receive either oseltamivir (75 mg), amantadine (100 mg), and ribavirin (600 mg) combination therapy or oseltamivir monotherapy twice daily for 5 days, given orally, and participants were followed up for 28 days. Blinded treatment kits were used to achieve masking of patients and staff. The primary endpoint was the percentage of participants with virus detectable by PCR in nasopharyngeal swab at day 3, and was assessed in participants who were randomised, had influenza infection confirmed by the central laboratory on a baseline nasopharyngeal sample, and had received at least one dose of study drug. Safety assessment was done in all patients in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, number NCT01227967.

FINDINGS

Between March 1, 2011, and April 29, 2016, 633 participants were randomly assigned to receive combination antiviral therapy (n=316) or monotherapy (n=317). Seven participants were excluded from analysis: three were not properly randomised, three withdrew from the study, and one was lost to follow-up. The primary analysis included 394 participants, excluding 47 in the pilot phase, 172 without confirmed influenza, and 13 without an endpoint sample. 80 (40·0%) of 200 participants in the combination group had detectable virus at day 3 compared with 97 (50·0%) of 194 (mean difference 10·0, 95% CI 0·2-19·8, p=0·046) in the monotherapy group. The most common adverse events were gastrointestinal-related disorders, primarily nausea (65 [12%] of 556 reported adverse events in the combination group vs 63 [11%] of 585 reported adverse events in the monotherapy group), diarrhoea (56 [10%] of 556 vs 64 [11%] of 585), and vomiting (39 [7%] of 556 vs 23 [4%] of 585). There was no benefit in multiple clinical secondary endpoints, such as median duration of symptoms (4·5 days in the combination group vs 4·0 days in the monotherapy group; p=0·21). One death occurred in the study in an elderly participant in the monotherapy group who died of cardiovascular failure 13 days after randomisation, judged by the site investigator as not related to study intervention.

INTERPRETATION

Although combination treatment showed a significant decrease in viral shedding at day 3 relative to monotherapy, this difference was not associated with improved clinical benefit. More work is needed to understand why there was no clinical benefit when a difference in virological outcome was identified.

FUNDING

National Institute of Allergy and Infectious Diseases, National Institutes of Health, USA.

The Effects of Exercise on Dopamine Neurotransmission in Parkinson's Disease: Targeting Neuroplasticity to Modulate Basal Ganglia Circuitry

Animal studies have been instrumental in providing evidence for exercise-induced neuroplasticity of corticostriatal circuits that are profoundly affected in Parkinson’s disease. Exercise has been implicated in modulating dopamine and glutamate neurotransmission, altering synaptogenesis, and increasing cerebral blood flow. In addition, recent evidence supports that the type of exercise may have regional effects on brain circuitry, with skilled exercise differentially affecting frontal-striatal related circuits to a greater degree than pure aerobic exercise. Neuroplasticity in models of dopamine depletion will be reviewed with a focus on the influence of exercise on the dorsal lateral striatum and prefrontal related circuitry underlying motor and cognitive impairment in PD. Although clearly more research is needed to address major gaps in our knowledge, we hypothesize that the potential effects of exercise on inducing neuroplasticity in a circuit specific manner may occur through synergistic mechanisms that include the coupling of an increasing neuronal metabolic demand and increased blood flow. Elucidation of these mechanisms may provide important new targets for facilitating brain repair and modifying the course of disease in PD.

Noncardiac chest pain: the role of the cardiologist--a national survey

BACKGROUND

The current assumption is that noncardiac chest pain (NCCP) patients diagnosed by a cardiologist are commonly referred to a gastroenterologist for further evaluation. Thus far, there are no studies that assess the clinical approach and referral patterns of cardiologists when evaluating subjects with NCCP.

AIM

To determine the extent of involvement of cardiologists in the management of NCCP patients.

METHODS

Cardiologists were randomly selected from the American College of Cardiology national membership list and sent a 20-item questionnaire that included demographic information, characteristics of practice, preferences of diagnostic tests, referral patterns, and treatment plans.

RESULTS

A total of 246 (33%) cardiologists returned the questionnaire. A mean of 12.6% of patients were diagnosed with NCCP and 45.5% were treated by a cardiologist in the past 6 months. Of the NCCP patients that were referred, most ended up in the primary care physician clinic (45.9%) followed by gastroenterologist clinic (29.3%). Most cardiologists are either comfortable (35%) or very comfortable (43.1%) in diagnosing NCCP. Proton pump inhibitors (44.9%), lifestyle modifications (28.7%), and H2 blockers (11.8%) are the three most commonly used therapeutic modalities for NCCP.

CONCLUSION

Cardiologists manage about half of the diagnosed NCCP patients by themselves. Of those NCCP patients that are referred, cardiologists prefer to send them to a primary care physician rather than a gastroenterologist.

Attitudes and referral patterns of primary care physicians when evaluating subjects with noncardiac chest pain--a national survey

Noncardiac chest pain (NCCP) may affect up to 23% of the U.S. population. The clinical approach and referral patterns of primary care physicians (PCPs) when evaluating NCCP subjects are unknown. We aimed to determine the preferences of diagnostic tests, referral patterns, and treatment plans of NCCP patients by PCPs. PCPs were randomly selected from the American Medical Association national membership list. A 24-item questionnaire was mailed, which focused on demographic information, characteristics of practice, preferences of diagnostic tests, referral patterns, and treatment plans. Two hundred five (40%) PCPs returned the questionnaire (mean age, 49; 77% males; practice type--community-based, 40.5%; hospital-based, 10.7%; and combined, 47.3%; physician type--internists, 46.3%; family physicians, 44.4%; general practitioners, 4.9%; and others, 2.9%). The mean number of NCCP patients seen in the past 6 months was 108 (6.4% of total patients) and 79.5% were treated primarily by PCPs. The three most common diagnostic tests used were empirical proton pump inhibitor (PPI) trial (45.6%), chest radiograph (39.9%), and upper endoscopy (18.7%). Most PCPs reported that they are either comfortable (44.6%) or very comfortable (21.2%) in diagnosing NCCP. The three most commonly used therapeutic modalities for NCCP were PPIs (37.8%), lifestyle modification (33.7%), and H2 blockers (12.4%). Of those NCCP patients referred to a subspecialist, most ended up in gastroenterology (75.6%), followed by cardiology (7.8%) and pulmonary (1.6%) clinics. We conclude that most PCP's diagnose and treat NCCP patients without referring them to a gastroenterologist. However, diagnostic and treatment strategies may not follow the current understanding and knowledge of the disorder.

Comparative evaluation of measles virus-specific RT-PCR methods through an international collaborative study

Comparison of RT-PCR assays established in house at various places revealed that laboratories could differ in sensitivity by as much as 1,000-fold in terms of the ability to detect measles virus sequences in clinical samples. The study indicates that PCR findings, positive or negative, are questionable if they are not supported by the associated data demonstrating the overall sensitivity of the assay applied. Measles virus-specific RT-PCR-based assays need to be validated using standard virus preparation or nucleic acid-based target templates. A correlation between real-time quantitative PCR and the conventional PCR for measles virus is highly desirable.

Immune-globulin prophylaxis of respiratory syncytial virus infection in patients undergoing stem-cell transplantation

Thirty-two patients undergoing allogeneic hematopoietic stem-cell transplantation were given respiratory syncytial virus (RSV) immune globulin (RSVIG) at the time of transplantation and again 3 weeks later. Antibody titers to RSV, human parainfluenza virus 3, measles, and influenza H1N1, H3N2, and B were measured prior to administration of RSVIG and 6 more times over the course of the subsequent 6 weeks. Baseline antiviral titers and increases in antibody after administration of RSVIG were extremely variable for all the viruses. In 18 patients in whom the baseline titers of antibody titers to RSV-F protein were 1:640-1:2048, there was a 7.7-fold initial increase in these titers after the first dose of RSVIG, compared with a 2.1-fold increase in 14 patients with baseline titers of 1:4096-1:20,840; increases in titers of antibody against the other viruses after the first dose of RSVIG reflected similar variability. The subset of patients with the lowest titers appear to receive the greatest benefit from administration of RSVIG.

Evaluation of an early two-dose measles vaccination schedule

Vaccination at 6 months of age followed by routine revaccination is recommended when exposure of infants to measles is likely. Dade County, Florida, began this early two-dose schedule during a large epidemic in 1986-1987 (i.e., 22% of cases occurred in infants aged 6-11 months). This schedule was continued routinely in high-risk areas. The effect of an early two-dose schedule on measles prevention in the county was examined by comparing measles vaccination coverage and epidemiology before (1985-1987) and after (1988-1996) the schedule became routine. To assess serologic response, seroprevalence of measles antibody among children aged 4-6 years in 1995 was examined. To evaluate vaccine effectiveness, a case-control study was conducted among preschool-aged children. Among those aged 2 years, vaccination coverage with > or =1 dose increased from 75% to 94% in 1996. The number of annual cases declined, and endemic measles transmission reportedly ended after 1993. Seroprevalence of plaque reduction neutralization antibody (titer > 1:120) among those receiving vaccination according to an early two-dose schedule and a single dose at age > or =12 months was 94% (95% confidence interval: 89, 98) and 98% (95% confidence interval: 95, 100). In these groups, vaccine effectiveness was comparably high. Early two-dose measles vaccination is associated with improved coverage and a comparably high level of humoral immunity and clinical protection as a single dose at age > or =12 months. This strategy can be useful in areas at high risk for measles among infants.

Immune responses to measles and mumps vaccination of infants at 6, 9, and 12 months

Immunizing infants against measles at the youngest age possible has the potential to reduce morbidity and mortality. The ability of infants at 6, 9, or 12 months to respond to measles and mumps vaccines was evaluated by measuring T cell proliferation, interferon-gamma production, and neutralizing antibody titers before and after vaccination. Infants in all age groups had equivalent cellular immune responses to measles or mumps viruses, with or without passive antibodies when immunized. In contrast, 6-month-old infants without passive antibodies had low geometric mean titers of antibody to measles or mumps viruses and low seroconversion rates. Geometric mean titers of antibody to measles virus increased if infants were revaccinated at 12 months. Six-month-old infants had limited humoral responses to paramyxovirus vaccines, whereas cellular immunity was equivalent to that of older infants. T cell responses can be established by immunization with these live attenuated virus vaccines during the first year, despite the presence of passive antibodies.

Macrophage colony-stimulating factor antagonists inhibit replication of HIV-1 in human macrophages

Macrophages infected with HIV-1 produce high levels of M-CSF and macrophage-inflammatory protein-1alpha (MIP-1alpha). M-CSF facilitates the growth and differentiation of macrophages, while the chemotactic properties of MIP-1alpha attract both T lymphocytes and macrophages to the site of HIV infection. Studies described in this work indicate M-CSF may function in an autocrine/paracrine manner to sustain HIV replication, and data suggest possible therapeutic strategies for decreasing viral load following HIV infection. We show that macrophage infection with measles virus or respiratory syncytial virus, in contrast to HIV-1, results in production of MIP-1alpha, but not M-CSF. Thus, M-CSF appears to be specifically produced upon infection of macrophages with HIV-1. Furthermore, addition of M-CSF antagonists to HIV-1-infected macrophages, including anti-M-CSF monoclonal or polyclonal Abs or soluble M-CSF receptors, dramatically inhibited HIV-1 replication and reduced production of MIP-1alpha. Our results suggest that biologic antagonists for M-CSF may represent novel strategies for inhibiting the spread of HIV-1 by 1) blocking virus replication in macrophages, 2) reducing recruitment of HIV-susceptible T cells and macrophages by MIP-1alpha, and 3) preventing the establishment and maintenance of infected macrophages as a reservoir for HIV.

Evaluation of vaccines, interferons and cell substrates for pestivirus contamination

Pestiviruses are potential contaminants of biological products produced in bovine or porcine cells or manufactured via processes using animal-derived raw materials such as bovine serum. In order to investigate possible contamination of products including those manufactured and/or licensed in the US, 38 lots of viral vaccines and five lots of interferon alpha (IFNalpha) were tested by reverse transcriptase polymerase chain reaction (RT-PCR) for the presence of bovine viral diarrhoea virus (BVDV). All vaccines and interferons were negative for contaminating BVDV RNA when tested by RT-PCR, with the exception of an experimental live viral vaccine that had been produced in BVDV contaminated rabbit kidney cells. Cell lines commonly used to produce biological products and vaccines were experimentally infected with the NADL strain of BVDV to determine if they were permissive for virus replication. MRC-5 and WI-38 cells were not infected. In contrast, Vero, CHO and CEF cells showed evidence of pestivirus infection. Taken together these data suggested that currently licensed viral vaccines were unlikely to be contaminated with pestiviruses. However, cell banks derived from non-human primate, hamster or rabbit kidney cell lines, or cultures of primary chick embryo fibroblasts, may be infected with BVDV if exposed to pestivirus contaminated raw materials during manufacture.

Family adjustment following disclosure of homosexuality by a member: themes discerned in narrative accounts

Disclosure of homosexuality by a family member frequently creates a crisis within the family. Previous research has focused primarily on families' response to this initial crisis and how they cope with and transform initial negative reactions. Little attention has been given to how families respond to disclosure over time and to how families integrate a gay or lesbian family member--and his or her relationships--once they have come to accept his or her homosexuality. Using a narrative approach and interviewing whole families, this project explores these questions. We present 12 themes we found consistently recurring in family members' narratives. We discuss the relationship between these themes and current models in the literature within the context of heterosexism and suggest that this approach may represent a first step in developing a model of successful adaptation subsequent to disclosure.

Patterns of family caregiving and support provided to older psychiatric patients in long-term care

Data on patterns of relationships and caregiving between older, institutionalized chronically mentally ill patients and their families were gathered in brief face-to-face interviews with 109 patients randomly selected from residents age 45 or older in a large intermediate care facility in Chicago. Three-fourths of the sample maintained some form of family contact. One-third had been married or had children. Siblings were the most frequently identified family contact and support. The results suggests that older, institutionalized psychiatric patients continue to have family contact and that siblings and offspring become increasingly important as patients age.

Divergence of binding, signaling, and biological responses to recombinant human hybrid IFN

Three human IFN-alpha hybrids, HY-1 [IFN-alpha21a(1-75)/alpha2c(76-165)], HY-2 [IFN-alpha21a(1-95)/alpha2c(96-165)], and HY-3 [IFN-alpha2c(1-95)/alpha21a(96-166)], were constructed, cloned, and expressed. The hybrids had comparable specific antiviral activities on Madin-Darby bovine kidney (MDBK) cells but exhibited very different antiproliferative and binding properties on human Daudi and WISH cells and primary human lymphocytes. Our data suggest that a portion of the N-terminal region of the molecule is important for interaction with components involved in binding of IFN-alpha2b while the C-terminal portion of IFN is critical for antiproliferative activity. A domain affecting the antiproliferative activity was found within the C-terminal region from amino acid residues 75-166. The signal transduction properties of HY-2 and HY-3 were evaluated by EMSA and RNase protection assays. Both HY-2 and HY-3 induced activation of STAT1 and 2. However, HY-2 exhibited essentially no antiproliferative effects at concentrations that activated STAT1 and 2. Additionally, at concentrations where no antiproliferative activity was seen, HY-2 induced a variety of IFN-responsive genes to the same degree as HY-3. RNase protection assays also indicate that, at concentrations where no antiproliferative activity was seen for HY-2, this construct retained the ability to induce a variety of IFN-inducible genes. These data suggest that the antiproliferative response may not be solely directed by the activation of the STAT1 and STAT2 pathway in the cells tested.

IL-12, IFN-gamma, and T cell proliferation to measles in immunized infants

Measles infection in infants is associated with severe complications, and secondary infections are attributed to generalized immunosuppression. Measles binding to its monocyte receptor down-regulates IL-12 which is expected to diminish Th1-like cytokine responses, including IFN-gamma. Whether young infants can be immunized effectively against measles is an important public health issue. We evaluated Ag-specific IL-12, IFN-gamma, and T cell responses of infants at 6 (n = 60), 9 (n = 46), or 12 mo (n = 56) of age and 29 vaccinated adults. IL-12 and IFN-gamma release by PBMC stimulated with measles Ag increased significantly after measles immunization in infants. IL-12 and IFN-gamma concentrations were equivalent in younger and older infants, but IL-12 concentrations were significantly lower in infants than in adults (p = 0.04). IL-12 production by monocytes was down-regulated by measles; the addition of recombinant human IL-12 enhanced IFN-gamma production by PBMC stimulated with measles Ag, but infant T cells released significantly less IFN-gamma than adult T cells under this condition. Of particular interest, the presence of passive Abs to measles had no effect on the specific T cell proliferation or IFN-gamma production after measles stimulation. Cellular immunity to measles infection and vaccination may be limited in infants compared with adults as a result of less effective IFN-gamma and IL-12 production in response to measles Ags. These effects were not exaggerated in younger infants compared with effects in infants who were immunized at 12 mo. In summary, infant T cells were primed with measles Ag despite the presence of passive Abs, but their adaptive immune responses were limited compared with those of adults.

A patient-centered model of acute care for elders

The patient centered "Acute Care of the Elderly Unit" is a multifaceted process of care that combines optimal geriatric nursing and medical care of elders within an interdisciplinary model. Although functional decline has been previously assumed to be an inevitable consequence of hospitalization, preliminary findings suggest that a patient centered multidisciplinary model of geriatric care prevents functional decline of hospitalized elders. In addition, the "low tech" interventions and cost savings outcomes suggests the feasibility of implementing this model of care in hospitals serving a variety of patient populations.

Prolonged STAT1 activation related to the growth arrest of malignant lymphoma cells by interferon-alpha

Multiple biologic effects of interferon-alpha (IFN-alpha), including cell growth inhibition and antiviral protection, are initiated by tyrosine phosphorylation of STAT proteins. Although this signal pathway has been intensively investigated, the relevance of STAT signal persistence has received scant attention. Using paired isogenic lymphoma cells (Daudi), which either are sensitive or resistant to growth inhibition by IFN-alpha, we found comparable initial tyrosine phosphorylation of multiple STAT proteins; however, the phosphorylation durations and associated DNA-binding activities diverged. Phosphorylation and DNA-binding capacity of STAT1 decreased after 4 to 8 hours in resistant cells, as compared with 24 to 32 hours in sensitive cells, whereas phosphorylation of STAT3 and STAT5b was briefer in both lines. Functional significance of the prolonged STAT1 signal, therefore, was explored by experimental interruption of tyrosine phosphorylation, either by premature withdrawal of the IFN-alpha or deferred addition of pharmacologically diverse antagonists: staurosporine (protein kinase inhibitor), phorbol 12-myristate 13-acetate (growth promoter), or aurintricarboxylic acid (ligand competitor). Results indicated that an approximately 18-hour period of continued STAT1 phosphorylation was associated with growth arrest, but that antiviral protection developed earlier. These differences provide novel evidence of a temporal dimension to IFN-alpha signal specificity and show that duration of STAT1 activation may be a critical variable in malignant cell responsiveness to antiproliferative therapy.

Antiproliferative action of interferon-alpha requires components of T-cell-receptor signalling

Signal transduction through both cytokine and lymphocyte antigen receptors shares some common pathways by which they initiate cellular responses, such as activation of mitogen-activated protein kinase(s). However, other signalling components appear to be uniquely coupled to each receptor. For example, the interferon receptors transduce regulatory signals through the JAK/STAT pathway, resulting in an inhibition of growth and of antiviral effects, whereas this pathway apparently plays no role in T-cell-receptor (TCR)-dependent gene expression. Conversely, signal transduction through the TCR requires the tyrosine kinases Lck and ZAP-70 and the tyrosine phosphatase CD45. Here we show that, unexpectedly, transmission of growth-inhibitory signals by interferon-alpha (IFN-alpha) in T cells requires the expression and association of CD45, Lck and ZAP-70 with the IFN-alpha-receptor signalling complex.

Effect of vitamin A supplementation on measles vaccination in nine-month-old infants

OBJECTIVE

Childhood immunization programs have been suggested as an infrastructure to deliver vitamin A supplements to children in developing countries. The effects of giving vitamin A, a potent immune enhancer, with measles immunization to nine-month-old infants is unknown.

METHODS

A randomized, double-masked, placebo-controlled clinical trial of vitamin A, 100,000 IU at the time of standard titer Schwarz measles immunization was conducted with nine-month-old infants in Bogor District, West Java, Indonesia. Antibody titers to measles were measured at baseline and one and six months following immunization.

RESULTS

394 infants received measles immunization, and 37 infants (9.4%) had baseline antibody titers > 1:120, which is consistent with previous natural measles infection. Of the remaining infants, 98.8% seroconverted to measles, and 99.3% had titers consistent with protection against measles six months postimmunization. Seroconversion rates were similar in vitamin A and placebo treatment groups.

CONCLUSION

High dose vitamin A supplementation can be given without reducing seroconversion to standard titer Schwatz measles immunization in nine-month-old infants.

Reduced seroconversion to measles in infants given vitamin A with measles vaccination

Administration of 100,000 IU vitamin A at the time of measles immunisation is currently recommended for infants in developing countries. However, the safety and value of giving vitamin A, a potent immune enhancer, with live measles virus vaccines are unknown. We conducted a randomised, double-blind, placebo-controlled clinical trial in Indonesia to evaluate the effect of simultaneous vitamin A supplementation on the immune response to measles immunisation at six months of age. 336 infants received either vitamin A (100,000 IU) or placebo when immunised with standard-titre Schwarz measles vaccine. 82% of infants seroconverted to measles. In a multiple logistic regression model adjusting for maternal antibody titres, vitamin A supplementation was associated with a lower likelihood of seroconversion to measles (odds ratio 0.40, 95% CI 0.19-0.88), and girls were less likely to seroconvert than boys (0.34, 0.15-0.76). Immunisation with standard-titre Schwarz vaccine at six months of age in this study population is characterised by high seroconversion rates. However, simultaneous high-dose vitamin A may interfere with seroconversion to live measles vaccine in infants with maternal antibody.

A divalent metal ion binding site in the kinase insert domain of the alpha-platelet-derived growth factor receptor regulates its association with SH2 domains

To investigate the effects of metal ion binding to the alpha-PDGFR kinase insert domain, a PCR product representing amino acid residues 691-795 (104 amino acids) was bacterially expressed and purified. Secondary structure prediction and circular dichroism spectroscopy indicated this domain to be a mixed alpha + beta protein with a large coil/turn contribution. This 16 kDa, soluble, nonphosphorylated domain bound to 45Ca2+ and 65Zn2+ through a common shared site. Of the unlabeled divalent and trivalent metal ions tested, Ho3+ = Zn2+ > Ni2+ > Ca2+ = Mn2+ > Mg2+, Ba2+ in competing for 45Ca2+ binding to this domain. In the presence of Ca2+ ions, the conformation of the KI domain changed significantly, and this changed conformation was resistant to subtilisin proteolysis. However, in the presence of Zn2+ ions, the conformation of the KI domain changed only slightly. Nevertheless, Zn2+ ions were more effective in rendering the KI domain resistant to proteolysis as compared to that shown by Ca2+ ions. In vitro binding studies using purified baculovirus-expressed alpha-PDGFR showed a marked increase in binding the p85 N-SH2 domain in the presence of Ca2+ or Zn2+ ions (KD = 0.5 microM), suggesting that metal ion binding enhances association of the p85 N-SH2 domain with the receptor. To confirm this, association of the alpha-PDGFR with the p85 N-SH2 domain was tested in the presence of the KI domain. The nonphosphorylated KI domain was effective in competing with the alpha-PDGFR for the binding of the p85 N-SH2 domain. This effect was more pronounced in the presence of Ca2+ ions. Microinjection of this domain into Xenopus oocytes delayed maturation in the presence of insulin but not progesterone. This suggests that the KI domain has a correctly folded three-dimensional structure compatible with biological activity. Together these findings indicate that the recombinant alpha-PDGFR KI domain binds the p85 N-SH2 domain and this binding is modulated by the presence of a novel divalent metal ion binding site within its structure.