More problems, more money: Identifying and predicting high-cost rescue after colorectal surgery

Background

Successful rescue after elective surgery is associated with increased healthcare costs, but costs vary widely. Treating all rescue events the same may overlook targeted opportunities for improvement. The purpose of this study was to predict high-cost rescue after elective colorectal surgery.

Methods

We identified adult patients in the National Inpatient Sample (2016-2021) who underwent elective colectomy or proctectomy. Rescued patients were defined as those who underwent additional major procedures. Three groups were stratified: 1) uneventful recovery; 2) Low-cost rescue; 3) High-cost rescue. Multivariable Poisson regression was used to identify preoperative clinical predictors of high-cost versus low-cost rescue.

Results

We identified 448,590 elective surgeries, and rescued patients composed 4.8 %(21,635) of the total sample. The median increase in costs in rescued patients was $25,544(p < 0.001). Median total inpatient costs were $95,926 in the most expensive rescued versus $34,811 in the less expensive rescued versus $16,751 in the uneventfully discharged(p < 0.001). When comparing the secondary procedures between the less expensive and most expensive rescued groups, the most expensive had an increased proportion of reoperation (73.4 % versus 53.0 %,p < 0.001). When controlling for other factors and stratification by congestive heart failure due to an interaction effect, a reoperation was independently associated with high-cost rescue (RR with CHF = 3.29,95%CI:2.69-4.04; RR without CHF = 2.29,95%CI:1.97-2.67).

Conclusions

High-cost rescue after colorectal surgery is associated with disproportionately greater healthcare utilization and reoperation. For cost-conscious care, preemptive strategies that reduce reoperation-related complications can be prioritized.

Diverticulitis in Older Adults: Is Cognitive Impairment Associated With Outcomes?

INTRODUCTION

Older age is associated with increased prevalence of both diverticulitis and cognitive impairment. The association between cognitive impairment and outcomes among older adults presenting to the emergency department (ED) for diverticulitis is unknown.

METHODS

Adults aged ≥65 y presenting to an ED with a primary diagnosis of colonic diverticulitis were identified using the Nationwide Emergency Department Sample (2016-2019) and stratified by cognitive impairment status in this retrospective cohort study. Multivariable Poisson regression models adjusted for patient age, sex, Elixhauser Comorbidity Index, primary payer status, and presence of complicated diverticulitis quantified relative risk of a) inpatient admission, b) operative intervention, and c) in-hospital mortality comparing patients with or without a diagnosis code suggestive of cognitive impairment.

RESULTS

Among 683,444 older adults with an ED encounter for diverticulitis from 2016 to 2019, there were 468,226 patients with isolated colonic diverticulitis and 26,388 (5.6%) with comorbid cognitive impairment. After adjustment, the risk of inpatient admission for those with cognitive impairment was 18% higher than for those without cognitive impairment (adjusted relative risks [aRR]: 1.18, 95% confidence interval [CI]: 1.17-1.20). Those with cognitive impairment were 34% more likely to undergo colectomy than those without cognitive impairment (aRR: 1.34, 95% CI: 1.24-1.44). Older adults with cognitive impairment had a 32% greater mortality than those without cognitive impairment (aRR: 1.32, 95% CI: 1.05-1.67).

CONCLUSIONS

Among older adults presenting for ED care with a primary diagnosis of colonic diverticulitis, individuals with cognitive impairment had higher rates of hospitalization, operative intervention, and in-hospital mortality than those without cognitive impairment.

Arterial Diameter and Percentage of Monocytes are Sex-Dependent Predictors of Early Arteriovenous Fistula Maturation

BACKGROUND

Arteriovenous fistulae mature less frequently in women than in men, leading to inferior patency and decreased fistula utilization in women. We hypothesized that both anatomic and physiologic sex differences explain reduced maturation.

METHODS

The electronic medical records of patients who had a primary arteriovenous fistula created from 2016 to 2021 at a single center were reviewed; sample size was determined using a power calculation. Postoperative ultrasound and laboratory tests were obtained at least 4 weeks after fistula creation. Primary unassisted fistula maturation was determined up to 4 years postprocedure.

RESULTS

A total of 28 women and 28 men with a brachial-cephalic fistula were analyzed. The inflow brachial artery diameter was smaller in women than in men, both preoperatively (4.2 ± 0.9 vs. 4.9 ± 1.0 mm, P = 0.008) and postoperatively (4.8 ± 0.8 vs. 5.3 ± 0.9 mm, P = 0.039). Despite similar preoperative brachial artery peak systolic velocity, women had significantly lower postoperative arterial velocity (P = 0.027). Fistula flow was reduced in women, particularly in the midhumerus (747.0 ± 570.4 vs. 1,117.1 ± 471.3 cc/min, P = 0.003). Percentages of neutrophils and lymphocytes were similar among women and men 6 weeks after fistula creation. However, women had reduced monocytes (8.5 ± 2.0 vs. 10.0 ± 2.6%, P = 0.0168). Among 28 men, 24 of 28 (85.7%) achieved unassisted maturation, whereas only 15 of 28 (53.6%) women had fistulae that matured without intervention. Secondary analysis using logistic regression suggested that postoperative arterial diameter was associated with maturation in men, while postoperative monocyte percentage was associated with maturation in women.

CONCLUSIONS

Sex differences during arteriovenous fistula maturation are present in arterial diameter and velocity, suggesting that both anatomic and physiologic differences in arterial inflow contribute to sex differences in fistula maturation. In men, postoperative arterial diameter is correlated with maturation, whereas in women, the significantly lower proportion of circulating monocytes suggests a role for the immune response in fistula maturation.

Palliative Care in a Pandemic: A Multicenter Cohort of Critically Ill Patients with Coronavirus Disease 2019

Background: Trends in mortality, palliative care, and end-of-life care among critically ill patients with coronavirus disease 2019 (COVID-19) remain underreported. We hypothesized that use of palliative care and end-of-life care would increase over time, because improved understanding of the disease course and prognosis would potentially lead to more frequent use of these services. Patients and Methods: Adult patients with severe acute respiratory syndrome coronavirus 2 infection (SARS-CoV-2) during pandemic wave one (W1: March 2020 to September 2020) or wave two (W2: October 2020 to June 2021) admitted to an intensive care unit (ICU) in one of six northeastern U.S. hospitals were identified and clinical characteristics obtained. Vaccination data were unavailable. Outcomes of interest included mortality, palliative care consultation, and any end-of-life care (including hospice and comfort care). Results: There were 1,904 critically ill patients with COVID-19: 817 (42.9%) in W1 and 1,087 (57.1%) in W2. Patients received mechanical ventilation more often during W1 than W2 (52.9% vs. 46.3%; p = 0.004), with no difference in ICU or hospital length of stay between waves. Mortality between W1 and W2 was similar (31.2% vs. 30.9%; p = 0.888). There was no difference in use of palliative care or any end-of-life care between waves. Patients who died during W2 versus W1 were more likely to have received both mechanical ventilation (77.1% vs. 67.1%; p = 0.007) and palliative care services (52.1% vs. 41.2%; p = 0.009). However, logistic regression adjusted for demographics, baseline comorbid disease, and clinical characteristics showed no difference in mortality (odds ratio [OR], 1.15; 95% confidence interval [CI], 0.89-1.48), palliative care (OR, 1.08; 95% CI, 0.84-1.40), or any end-of-life care (OR, 1.05; 95% CI, 0.82-1.34) in W2 versus W1. Conclusions: Mortality among critically ill patients with COVID-19 has remained constant across two pandemic waves with no change in use of palliative or end-of-life care.

Association Between Time to First RNA-Negative Test Result Among People With Hepatitis C Virus Infection and Homelessness or Testing at a Correctional or Substance Use Treatment Facility, New York City

OBJECTIVE

Curative treatments for hepatitis C virus (HCV) infection are available, but access and barriers to treatment can delay initiation. We investigated the time to first negative RNA test result among people with HCV infection and examined differences by homeless status and whether people were tested at a correctional facility or substance use treatment facility.

METHODS

We used surveillance data to identify New York City residents first reported with HCV infection during January 1, 2015-December 31, 2018, with ≥1 positive RNA test result during January 1, 2015-November 1, 2019. We used Kaplan-Meier survival analysis to determine the time from the first positive RNA test result to the first negative RNA test result, with right-censoring at date of death or November 1, 2019. We determined substance use treatment, incarceration, or homelessness by ordering facility name and address or from patient residential address.

RESULTS

Of 13 952 people with an HCV RNA-positive test result first reported during 2015-2018, 6947 (49.8%) subsequently received an RNA-negative test result. Overall, 25% received an RNA-negative test result within 208 (95% CI, 200-216) days and 50% within 902 (95% CI, 841-966) days. Homelessness, incarceration, or substance use treatment was indicated for 4304 (30.9%) people, among whom 25% received an RNA-negative test result within 469 (95% CI, 427-520) days and <50% received an RNA-negative test result during the study period.

CONCLUSIONS

Efforts to connect people to treatment should occur soon after diagnosis, especially for people who could benefit from hepatitis C care coordination.

The Impact of Supportive Housing on Liver-Related Outcomes Among Persons With Hepatitis C Virus Infection

BACKGROUND

Hepatitis C virus (HCV) infection disproportionately impacts people experiencing homelessness. Hepatitis C virus can lead to negative health outcomes, including mortality. We evaluated the impact of a permanent supportive housing (PSH) program (ie, "treatment") on liver-related morbidity and mortality among persons with chronic homelessness and HCV infection.

METHODS

We matched records for persons eligible for a New York City PSH program (2007-2014) with Heath Department HCV and Vital Statistics registries and Medicaid claims. Among persons diagnosed with HCV before or 2 years posteligibility, we added stabilized inverse probability of treatment weights to negative binomial regression models to compare rates for liver disease-related emergency department visits and hospitalizations, and hazard ratios for mortality, by program placement 2 and 5 years posteligibility.

RESULTS

We identified 1158 of 8783 placed and 1952 of 19 019 unplaced persons with laboratory-confirmed HCV infection. Permanent supportive housing placement was associated with significantly reduced liver-related emergency department visits (adjusted rate ratio [aRR] = 0.76, 95% confidence interval [CI] = .61-.95), hospitalizations (aRR = 0.62, 95% CI = .54-.71), and all-cause (adjusted hazard ratio [aHR] = 0.65, 95% CI = .46-.92) and liver-related mortality (aHR = 0.72, 95% CI = .09-.83) within 2 years. The reduction remained significant for hospitalizations after 5 years.

CONCLUSIONS

Placement into PSH was associated with reduced liver-related morbidity and mortality among persons with HCV infection and chronic homelessness.

Detection of Recurrent Hepatitis C Viremia Using Surveillance Data, New York City

The introduction of direct-acting antivirals for treating hepatitis C virus (HCV) infection has greatly improved cure rates. However, persons with past HCV infection who engage in high-risk behaviors can be reinfected. Surveillance data from the New York City (NYC) Health Department were used to detect and investigate individuals cured during January 2014 to December 2016 who had a subsequent positive RNA test (recurrence) by April 2018. Clinical interpretation of recurrence was obtained using provider interviews and review of medical records available through Regional Health Information Organizations. Among 6938 cured individuals, 209 recurrence events were detected (2.7 per 100 person-years). Investigations were completed for 62 (30%) events. Of 38 investigated events occurring less than 12 months postcure, 17 (45%) were relapses; of 24 events occurring 12 or more months postcure, only one (4%) was a relapse. Understanding the timing, frequency, and clinical interpretation of HCV recurrence will guide HCV prevention and elimination efforts for NYC.

The Hepatitis C Clinical Exchange Network: A Local Health Department Partnership With Acute Care Hospitals to Promote Screening and Treatment of Hepatitis C Virus Infection

CONTEXT

As of 2015, an estimated 116000 New York City (NYC) residents had chronic hepatitis C, many of them undiagnosed. Although effective medications have been available since 2014 with the advent of direct-acting antivirals, provider-based barriers to treatment remain. The NYC Department of Health and Mental Hygiene (Health Department) coordinated the Hepatitis C Clinical Exchange Network (HepCX) from 2015 to 2019. The main goal of HepCX was to promote hepatitis C screening and treatment by hospital-based providers.

PROGRAM

The Health Department recruited hepatitis C champions (Champions) from acute care hospitals (n = 40) to promote improved hepatitis C care at their institutions. The Health Department provided technical assistance for hospitals to improve electronic medical record (EMR) systems and implement reflex RNA testing, coordinated trainings to increase capacity to treat hepatitis C, and distributed dashboards containing facility-specific testing and treatment metrics.

IMPLEMENTATION

By the end of the project period (2019), most hospitals (36/40; 90%) reported having a screening alert for baby boomers in their EMR system and 34 (85%) reported performing reflex RNA testing after a positive hepatitis C antibody test. The Health Department coordinated opportunities for Champions to share their work with providers from network hospitals at meetings and webinars and provided clinical education on hepatitis C treatment in partnership with a local nonprofit organization focused on liver health. Facility-specific dashboards were distributed annually to hospital leadership. RNA confirmation testing increased from an average of 57% in 2015 to 85% in 2018. Treatment initiation rates remained similar over 2 years, averaging 39% in 2017 and 38% in 2018.

DISCUSSION

HepCX was a multipronged initiative designed to promote hepatitis C testing and treatment initiation among providers at NYC acute care hospitals. Improvements were observed in confirmatory testing rates; however, treatment initiation rates did not change. Further efforts should be targeted to hospitals in need of additional resources for linkage to care and treatment of hepatitis C.

Telephone Patient Navigation Increases Follow-Up Hepatitis B Care in the Postpartum Period for Immigrants Living in New York City

Hepatitis B is a major public health threat which leads to serious liver disease or cancer and disproportionately impacts immigrants. Pregnant people are routinely tested for hepatitis B to prevent perinatal transmission but may themselves not receive appropriate education and referrals. People contacted as part of the local health department's perinatal hepatitis B prevention program were offered culturally appropriate telephone patient navigation services to test if this would improve adherence with postpartum hepatitis B care. Four-hundred and nine people were enrolled in the intervention. Using laboratory-reported surveillance data as the outcome measure, those receiving the intervention were 1.66 times as likely to see a hepatitis B care provider within 6 months of childbirth compared with those who did not. Culturally appropriate patient navigation can improve adherence with recommended hepatitis B care in the postpartum period. Health departments can use similar interventions to address liver health disparities in immigrant populations.

COVID-19 Outbreak - New York City, February 29-June 1, 2020

New York City (NYC) was an epicenter of the coronavirus disease 2019 (COVID-19) outbreak in the United States during spring 2020 (1). During March-May 2020, approximately 203,000 laboratory-confirmed COVID-19 cases were reported to the NYC Department of Health and Mental Hygiene (DOHMH). To obtain more complete data, DOHMH used supplementary information sources and relied on direct data importation and matching of patient identifiers for data on hospitalization status, the occurrence of death, race/ethnicity, and presence of underlying medical conditions. The highest rates of cases, hospitalizations, and deaths were concentrated in communities of color, high-poverty areas, and among persons aged ≥75 years or with underlying conditions. The crude fatality rate was 9.2% overall and 32.1% among hospitalized patients. Using these data to prevent additional infections among NYC residents during subsequent waves of the pandemic, particularly among those at highest risk for hospitalization and death, is critical. Mitigating COVID-19 transmission among vulnerable groups at high risk for hospitalization and death is an urgent priority. Similar to NYC, other jurisdictions might find the use of supplementary information sources valuable in their efforts to prevent COVID-19 infections.

Health Department Efforts to Increase Hepatitis C RNA Testing Among People Appearing Out of Care: Comparison of Outreach Approaches, New York City, 2017

OBJECTIVES

Hepatitis C virus (HCV) infection is a serious health problem in New York City. Although curative treatments are available, many people are out of care. The New York City Department of Health and Mental Hygiene (DOHMH) used surveillance data and various outreach methods to attempt to link to care people diagnosed with HCV infection from 2010 through 2015.

METHODS

We randomly assigned people out of care (ie, no HCV test >6 months after first report) to 4 outreach groups: no outreach (control group); letter only; letter and telephone call; and letter, text message, and telephone call. Three months after outreach ended, we analyzed surveillance data to identify people with a subsequent HCV RNA or genotype test suggesting linkage to care.

RESULTS

Of 2626 selected people, 199 (7.6%) had a subsequent HCV test. People in all 3 outreach groups had higher odds of a subsequent test than people in the control group (letter only: adjusted odds ratio [aOR] = 1.81 [95% CI, 1.18-2.91]; letter and telephone: aOR = 3.11 [95% CI, 1.67-5.79]; letter, text, and telephone: aOR = 3.17 [95% CI, 1.48-6.51]). People in the letter and telephone group had higher odds of a subsequent test than people in the letter-only group (aOR = 1.72; 95% CI, 1.04-2.74). Most people in the letter and telephone (136/200, 68.0%) and the letter, text, and telephone (71/99, 71.7%) groups could not be reached, primarily because telephone numbers were incorrect or out of service.

CONCLUSION

Reaching out to people soon after first report or prioritizing groups in which more recent contact information can be found might improve outcomes of future outreach.

Impact of the Centers for Disease Control and Prevention Recommendation and State Law on Birth Cohort Hepatitis C Screening of New York City Medicaid Recipients

INTRODUCTION

The Centers for Disease Control and Prevention estimated that, during 1999-2008, people born in 1945-1965 (the baby boomer generation) represented approximately 75% of people infected with hepatitis C virus and 73% of hepatitis C virus-associated deaths and are at greatest risk for hepatocellular carcinoma and liver disease. In 2012, the Centers for Disease Control and Prevention recommended one-time hepatitis C virus screening for people born during 1945-1965. In addition, New York State enacted a Hepatitis C Virus Testing Law in 2014. This analysis assesses the impacts of the 2012 recommendation and 2014 New York State Testing Law on hepatitis C virus screening rates among New York City Medicaid-enrolled recipients born during 1945-1965.

METHODS

The eligible population was determined quarterly as the number of Medicaid recipients continuously enrolled for 12 months with neither a prior hepatitis C virus diagnosis nor antibody test since 2005. Quarterly screening rates during 2010-2017 were examined using interrupted time series analysis. Data were analyzed in 2018-2019.

RESULTS

In 2010-2017, the highest screening rate occurred in the quarter immediately after the law (33.64 per 1,000 Medicaid recipients). There was no change in screening rates after the Centers for Disease Control and Prevention recommendation and a significant increase after the New York State Law, which was not sustained.

CONCLUSIONS

Hepatitis C virus screening rates increased in the quarter after the 2014 New York State Hepatitis C Virus Testing Law became effective. Additional efforts are needed to screen baby boomers and people who were recently infected with hepatitis C virus related to opioid use.

Hepatitis C infection among men who have sex with men living with HIV in New York City, 2000-2015

OBJECTIVES

To calculate the rate of hepatitis C virus (HCV) among HIV-infected men who have sex with men (MSM) with no reported history of injection drug use (IDU), and to assess whether disparities exist in HIV/HCV coinfection by race/ethnicity and neighbourhood poverty level within this population in New York City.

METHODS

HIV-positive men who reported sex with men and did not report IDU at the time of HIV diagnosis, diagnosed through 2015 and alive as of 2000, were matched to people with HCV first reported to the New York City Department of Health and Mental Hygiene between 2000 and 2015. Those with HCV reported before or within 90 days of HIV infection were excluded. A multivariable Cox proportional hazards model was fit to compare the association between HCV diagnosis, race/ethnicity and neighbourhood poverty level.

RESULTS

From 2000 to 2015, 54 488 non-IDU MSM were diagnosed with HIV, of whom 2762 (5.1%) were diagnosed with HCV after HIV diagnosis, yielding an overall age-adjusted HCV diagnosis rate of 512 per 100 000 person-years. HIV/HCV coinfection was significantly higher among non-Latino blacks (adjusted HR (aHR)=1.24, 95% CI 1.11 to 1.40) compared with non-Latino whites and among persons living in high-poverty neighbourhoods compared with those in low-poverty neighbourhoods (aHR=1.17, 95% CI 1.01 to 1.35) after stratification by year of HIV diagnosis.

CONCLUSION

Disparities in HIV/HCV coinfection among HIV-positive MSM were observed by race/ethnicity and neighbourhood poverty level. Routine HCV screening is recommended for people infected with HIV. People coinfected with HIV and HCV should be linked to HCV care, treated and cured to reduce morbidity and mortality, and to avoid ongoing HCV transmission.

Surveillance-Based Estimate of the Prevalence of Chronic Hepatitis B Virus Infection, New York City, 2016

OBJECTIVES

Chronic hepatitis B virus (HBV) infection is a lifelong infection that can cause serious liver damage and liver cancer. The last surveillance-based prevalence estimate of chronic HBV infection in New York City was 1.2% in 2008; however, it did not account for persons with undiagnosed infection. The objective of this study was to calculate the prevalence of chronic HBV infection, including undiagnosed infection, for 2016 by using surveillance data and literature-based information.

METHODS

We calculated the number of persons with diagnosed chronic HBV infection (2000-2016) who were alive and living in New York City in 2016 by using routine surveillance data. We estimated the percentage of persons with undiagnosed chronic HBV infection by using birth region-specific percentages from the literature, weighted by the proportion of the New York City population with diagnosed chronic HBV infection from the same birth region. We identified minimum, maximum, and most likely values for the percentage with undiagnosed chronic HBV infection to generate 95% certainty limits (CLs) of the prevalence estimate.

RESULTS

The prevalence of chronic HBV infection in 2016, including undiagnosed infection, in New York City was 2.7% (95% CL, 2.2%-3.6%), representing approximately 230 000 persons. The prevalence of diagnosed chronic HBV infection was 1.5%. The estimated prevalence among non-US-born residents was 6.9% (95% CL, 5.4%-8.9%).

CONCLUSIONS

The current burden of chronic HBV infection in New York City, especially for non-US-born residents, is substantial. A renewed focus and dedication of resources is required to increase the number of new diagnoses and improve provider capacity to care for the large number of persons with chronic HBV infection.

Evaluation of a hepatitis C clinical care coordination programme's effect on treatment initiation and cure: A surveillance-based propensity score matching approach

Hepatitis C (HCV) is a viral infection that if left untreated can severely damage the liver. Project INSPIRE was a 3 year HCV care coordination programme in New York City (NYC) that aimed to address barriers to treatment initiation and cure by providing patients with supportive services and health promotion. We examined whether enrolment in Project INSPIRE was associated with differences in HCV treatment and cure compared with a demographically similar group not enrolled in the programme. INSPIRE participants in 2015 were matched with a cohort of HCV-infected persons identified in the NYC surveillance registry, using full optimal matching on propensity scores and stratified by INSPIRE enrolment status. Conditional logistic regression was used to assess group differences in the two treatment outcomes. Two follow-up sensitivity analyses using individual pair-matched sets and the full unadjusted cohort were also conducted. Treatment was initiated by 72% (790/1130) of INSPIRE participants and 36% (11 960/32 819) of study-eligible controls. Among initiators, 65% (514/790) of INSPIRE participants compared with 47% (5641/11 960) of controls achieved cure. In the matched analysis, enrolment in INSPIRE increased the odds of treatment initiation (OR: 5.25, 95% CI: 4.47-6.17) and cure (OR: 2.52, 95% CI: 2.00-3.16). Results from the sensitivity analyses showed agreement with the results from the full optimal match. Participation in the HCV care coordination programme significantly increased the probability of treatment initiation and cure, demonstrating that care coordination for HCV-infected individuals improves treatment outcomes.

Effect of Hepatocellular Carcinoma on Mortality Among Individuals With Hepatitis B or Hepatitis C Infection in New York City, 2001-2012

Background

Hepatocellular carcinoma (HCC) is a complication of chronic hepatitis B and C virus (HBV and HCV) infection. New York City (NYC) has a high prevalence of HBV and HCV, and infected persons likely face increased mortality from HCC and other causes. We describe the mortality profile of NYC residents with HBV or HCV, emphasizing the contributions of HCC and HIV coinfection.

Methods

 Two existing data sets were combined to examine all individuals diagnosed with HBV or HCV in NYC first reported to the Health Department during 2001-2012 and their HCC, HIV, and vital status. Logistic regression was used to calculate the odds of HCC diagnosis by viral hepatitis status, whereas Cox proportional hazard regression was used to estimate the hazard of death by HCC/HIV status.

Results

In total, 120 952 and 127 933 individuals were diagnosed with HBV or HCV, respectively. HCV-infected individuals had 17% higher odds of HCC diagnosis than HBV-infected individuals and 3.2 times higher odds of HIV coinfection. Those with HCV were twice as likely to die during the study period (adjusted hazard ratio, 2.04; 95% confidence interval, 1.96-2.12). The risk of death increased for those with HIV or HCC and was highest for those with both conditions.

Conclusions

HCC and HIV represent substantial risks to survival for both HBV- and HCV-infected individuals. Individuals with HBV need close monitoring and treatment, when indicated, and routine HCC screening. Those with HCV need increased, timely access to curative medications before developing liver disease.

A Surveillance-Based Hepatitis C Care Cascade, New York City, 2017

OBJECTIVES

The care cascade, a method for tracking population-level progression from diagnosis to cure, is an important tool in addressing and monitoring the hepatitis C virus (HCV) epidemic. However, little agreement exists on appropriate care cascade steps or how best to measure them. The New York City (NYC) Department of Health and Mental Hygiene (DOHMH) sought to construct a care cascade by using laboratory surveillance data with clinically relevant categories that can be readily updated over time.

METHODS

We identified all NYC residents ever reported to the DOHMH surveillance registry with HCV through June 30, 2017 (n = 175 896). To account for outmigration, death, or treatment before negative RNA results became reportable to the health department, we limited the population to people with any test reported since July 1, 2014. Of these residents, we identified the proportion with a reported positive RNA test and estimated the proportion treated and cured since July 2014 by using DOHMH-developed surveillance-based algorithms.

RESULTS

Of 78 886 NYC residents ever receiving a diagnosis of HCV and tested since July 1, 2014, a total of 70 397 (89.2%) had ever been reported as RNA positive through June 30, 2017; 36 875 (46.7%) had initiated treatment since July 1, 2014, and 23 766 (30.1%) appeared cured during the same period.

CONCLUSION

A substantial gap exists between confirming HCV infection and initiating treatment, even in the era of direct-acting antivirals. Using this cascade, we will monitor progress in improved treatment and cure of HCV in NYC.

Vaccination establishes clonal relatives of germinal center T cells in the blood of humans

Heit et al. describe that in humans, circulating memory T follicular helper cells (cTfh) have a clonal relationship to germinal center Tfh (GCTfh) cells. Upon vaccination, such memory cTfh respond with clonal expansion, activation, and simultaneous expression of a GCTfh-like phenotype.

Germinal center T follicular helper cells (GCTfh) in lymphatic tissue are critical for B cell differentiation and protective antibody induction, but whether GCTfh establish clonal derivatives as circulating memory T cells is less understood. Here, we used markers expressed on GCTfh, CXCR5, PD1, and ICOS, to identify potential circulating CXCR5⁺CD4⁺ Tfh-like cells (cTfh) in humans, and investigated their functional phenotypes, diversity, and ontogeny in paired donor blood and tonsils, and in blood after vaccination. Based on T cell receptor repertoire analysis, we found that PD-1–expressing cTfh and tonsillar GCTfh cells were clonally related. Furthermore, an activated, antigen-specific PD1⁺ICOS⁺ cTfh subset clonally expanded after booster immunization whose frequencies correlated with vaccine-specific serum IgG; these phenotypically resembled GCTfh, and were clonally related to a resting PD1⁺ICOS⁻ CD4⁺ memory T cell subset. Thus, we postulate that vaccination establishes clonal relatives of GCTfh within the circulating memory CD4⁺CXCR5⁺PD1⁺ T cell pool that expand upon reencounter of their cognate antigen.

Hepatocellular Carcinoma and Viral Hepatitis in New York City

BACKGROUND

 The incidence and mortality rate of hepatocellular carcinoma (HCC) are increasing in the United States. Viral hepatitis infection is a primary risk factor for HCC. This study describes the relationship between viral hepatitis and HCC in New York City (NYC).

METHODS

 Viral hepatitis cases reported to the NYC Department of Health from 1999-2012 were matched to HCC cases diagnosed from 2001 to 2012 and reported to the New York State Cancer Registry. HCC cases were stratified by the presence or absence of viral hepatitis. Demographic characteristics, factors associated with specific causes of death, and survival time were analyzed for all HCC cases.

RESULTS

 From 2001-2012, a total of 8827 NYC residents had HCC diagnosed; 38.4% had hepatitis C virus (HCV) infection, 17.9% had hepatitis B virus (HBV) infection, and 2.2% had both. Patients with HCC were predominantly men (74.8%), with equal proportions of white non-Hispanic (28.6%) and Hispanic (28.9%) patients. Those with HBV infection were primarily Asian/Pacific Islanders (63.2%). The median survival time after HCC diagnosis for persons with HBV infection was 22.3 months, compared with 13.1 months for persons with HCV infection, and 6.9 months for noninfected persons. The 5-year survival rate was 37.5% for those with HBV infection, 20.0% for those with HCV infection, 29.5% among coinfected individuals, and 16.1% for those with neither infection reported.

CONCLUSIONS

 In NYC, most persons with HCC have viral hepatitis; the majority of viral hepatitis infections are due to HCV. Survival for persons with HCC differs widely by viral hepatitis status. This study highlights the importance of viral hepatitis prevention and treatment and HCC screening.

Perceived energy compensation following various sports: an age and sex comparison. Preliminary observations

Following periods of physical activity, it is not uncommon for exercisers to increase their energy intake as a reward deemed 'earned'. Consumers' awareness of the energy within food and expended from exercise has previously been found to be limited. Therefore, the aim was to investigate whether habitual exercisers (50 adults and 49 children from 5 sports clubs) were able to conceptualise the energy expenditure (EE), following 1 h of their regular sports training, into a quantifiable amount of perceived energy compensation (PEC) in the form of food (chocolate) or drink (sports drink). Mean percentage accuracy for the PEC against EE matched <30% (± 29%), a significant underestimation irrespective of sex or sport. Percentage accuracy failed to significantly correlate to age. These findings indicate a necessity to improve nutrition education surrounding the energy costs of exercise relative to the energy contained within foods/drinks for both adults and children.

A common mechanism of clinical HIV-1 resistance to the CCR5 antagonist maraviroc despite divergent resistance levels and lack of common gp120 resistance mutations

Background

The CCR5 antagonist maraviroc (MVC) inhibits human immunodeficiency virus type 1 (HIV-1) entry by altering the CCR5 extracellular loops (ECL), such that the gp120 envelope glycoproteins (Env) no longer recognize CCR5. The mechanisms of HIV-1 resistance to MVC, the only CCR5 antagonist licensed for clinical use are poorly understood, with insights into MVC resistance almost exclusively limited to knowledge obtained from in vitro studies or from studies of resistance to other CCR5 antagonists. To more precisely understand mechanisms of resistance to MVC in vivo, we characterized Envs isolated from 2 subjects who experienced virologic failure on MVC.

Results

Envs were cloned from subjects 17 and 24 before commencement of MVC (17-Sens and 24-Sens) and after virologic failure (17-Res and 24-Res). The Envs cloned during virologic failure showed broad divergence in resistance levels, with 17-Res Env exhibiting a relatively high maximal percent inhibition (MPI) of ~90% in NP2-CD4/CCR5 cells and peripheral blood mononuclear cells (PBMC), and 24-Res Env exhibiting a very low MPI of ~0 to 12% in both cell types, indicating relatively “weak” and “strong” resistance, respectively. Resistance mutations were strain-specific and mapped to the gp120 V3 loop. Affinity profiling by the 293-Affinofile assay and mathematical modeling using VERSA (Viral Entry Receptor Sensitivity Analysis) metrics revealed that 17-Res and 24-Res Envs engaged MVC-bound CCR5 inefficiently or very efficiently, respectively. Despite highly divergent phenotypes, and a lack of common gp120 resistance mutations, both resistant Envs exhibited an almost superimposable pattern of dramatically increased reliance on sulfated tyrosine residues in the CCR5 N-terminus, and on histidine residues in the CCR5 ECLs. This altered mechanism of CCR5 engagement rendered both the resistant Envs susceptible to neutralization by a sulfated peptide fragment of the CCR5 N-terminus.

Conclusions

Clinical resistance to MVC may involve divergent Env phenotypes and different genetic alterations in gp120, but the molecular mechanism of resistance of the Envs studied here appears to be related. The increased reliance on sulfated CCR5 N-terminus residues suggests a new avenue to block HIV-1 entry by CCR5 N-terminus sulfopeptidomimetic drugs.

The soy isoflavone genistein inhibits the reduction in Achilles tendon collagen content induced by ovariectomy in rats

The objective of this study was to evaluate the effects of genistein and moderate intensity exercise on Achilles tendon collagen and cross-linking in intact and ovariectomized (OVX) female Sprague-Dawley rats. Rats were separated into eight groups (n = 9/group): intact or OVX, treadmill exercised or sedentary, genistein-treated (300 mg/kg/day) or vehicle. After 6 weeks, tendons were assayed for the collagen-specific amino acid hydroxyproline and hydroxylyslpyridinoline (HP). Collagen content was not influenced by exercise (P = 0.40) but was lower (P < 0.001) in OVX-vehicle rats compared with intact vehicle rats (OVX: 894 ± 35 μg collagen/mg dry weight; intact: 1185 ± 72 μg collagen/mg dry weight). In contrast, collagen content in OVX rats treated with genistein was greater (P = 0.010, 1198 ± 121 μg collagen/mg dry weight) when compared with untreated rats and was not different from intact rats (P = 0.89). HP content was lower in OVX genistein-treated rats when compared with intact genistein-treated rats, but only within the sedentary animals (P = 0.05, intact-treated: 232 ± 39 mmol/mol collagen; OVX-treated: 144 ± 21 mmol/mol collagen). Our findings suggest that ovariectomy leads to a reduction in tendon collagen, which is prevented by genistein. HP content, however, may not have increased in proportion to the addition of collagen. Genistein may be useful for improving tendon collagen content in conditions of estrogen deficiency.

Evaluation of a manual DNA extraction protocol and an isothermal amplification assay for detecting HIV-1 DNA from dried blood spots for use in resource-limited settings

BACKGROUND

In resource-limited settings (RLS) dried blood spots (DBS) are collected on infants and transported through provincial laboratories to a central facility where HIV-1 DNA PCR testing is performed using specialized equipment. Implementing a simpler approach not requiring such equipment or skilled personnel could allow the more numerous provincial laboratories to offer testing, improving turn-around-time to identify and treat infected infants sooner.

OBJECTIVES

Assess performances of a manual DNA extraction method and helicase-dependent amplification (HDA) assay for detecting HIV-1 DNA from DBS.

STUDY DESIGN

60 HIV-1 infected adults were enrolled, blood samples taken and DBS made. DBS extracts were assessed for DNA concentration and beta globin amplification using PCR and melt-curve analysis. These same extracts were then tested for HIV-1 DNA using HDA and compared to results generated by PCR and pyrosequencing. Finally, HDA limit of detection (LOD) studies were performed using DBS extracts prepared with known numbers of 8E5 cells.

RESULTS

The manual extraction protocol consistently yielded high concentrations of amplifiable DNA from DBS. LOD assessment demonstrated HDA detected ∼470 copies/ml of HIV-1 DNA extracts in 4/4 replicates. No statistical difference was found using the McNemar's test when comparing HDA to PCR for detecting HIV-1 DNA from DBS.

CONCLUSIONS

Using just a magnet, heat block and pipettes, the manual extraction protocol and HDA assay detected HIV-1 DNA from DBS at levels that would be useful for early infant diagnosis. Next steps will include assessing HDA for non-B HIV-1 subtypes recognition and comparison to Roche HIV-1 DNA v1.5 PCR assay.

Improving memory span in children with Down syndrome

BACKGROUND

Down syndrome (DS) is characterized by impaired memory span, particularly auditory verbal memory span. Memory span is linked developmentally to several language capabilities, and may be a basic capacity that enables language learning. If children with DS had better memory span, they might benefit more from language intervention. The present study evaluates a home-based parent-implemented intervention designed to improve auditory memory span in children with DS.

METHOD

Sixteen children with DS, age 6-14, completed one or two 3-month periods of memory training using overt cumulative rehearsal and auditory-only procedures. Children were divided into two groups. Group 1 completed 3 months of memory training followed by 3 months of visual activities, followed by three more months of memory training. Group 2 had the opposite schedule. Before and after each 3-month period, children came into the laboratory for memory assessment.

RESULTS

Children improved in training sessions and a small amount on digit span, the primary proximal outcome assessment measure. Digit span improvement was linked to the memory training, as indicated by control comparisons and correlations. Improvement was correlated with language comprehension and verbal working memory, but not with non-verbal ability, age or home/behavioural variables. No improvement was evident on distal outcome measures (sentence memory and verbal working memory); however, a phonological similarity effect emerged coincidence with memory training, suggesting increased use of phonological codes in memory.

CONCLUSIONS

Results suggest that some children with DS can improve their auditory verbal memory span with home-based rehearsal training, at least in limited ways. Children with good language and verbal working memory skills may be the best candidates for this type of training, even though they may show only small improvements. Still, small improvements in a severely impaired function are noteworthy, and justify further investigation.

Nuclear import in digitonin-permeabilized cells

Import of proteins into the nucleus of a cell is a complex process that can be reconstituted in vitro. Digitonin-permeabilized cells are washed free of cytosolic factors to provide competent nuclei. Cytosolic factors for import are provided by an extract of Xenopus ovarian cells. Fluorochrome-conjugated probes, cloned proteins fused to green fluorescent protein, or antibodies to the protein of interest are used to visualize nuclear import. The system can also be used to identify nuclear localization sequences (NLS) of imported proteins.

Significance of non-calcified pulmonary nodules in patients with extrapulmonary cancers

BACKGROUND

This study sought to determine the rate and patterns of malignancy in patients with extrapulmonary cancers and non-calcified pulmonary nodules, and to develop a statistical model to guide clinicians regarding choice of patients for diagnostic biopsy.

METHOD

The medical records of 151 patients evaluated at the Memorial Sloan-Kettering Cancer Center between January 1999 and December 2001 for non-calcified pulmonary nodules were reviewed. Nodules were considered malignant based on the results of a diagnostic biopsy, and were considered benign if their appearance remained stable 2 years after the initial study, if they resolved, or if a biopsy showed a non-malignant condition.

RESULTS

Sixty four of 151 patients (42%) were diagnosed with malignant nodules; 32 had newly diagnosed lung cancers, 28 had metastatic spread of their primary cancers, and four had lesions that were either new cancers or of undetermined aetiology. On univariate analysis the likelihood of malignancy increased with nodule size, tobacco exposure, and the finding of a solitary nodule. On multivariable analysis only nodule size and tobacco exposure were predictive of malignancy. The model had good predictive accuracy (area under the curve 0.751) but had insufficient discrimination for use as a clinical tool to determine which patients should undergo diagnostic biopsy.

CONCLUSION

Nearly half the non-calcified pulmonary nodules identified in this series were malignant. Lung cancer was more common than metastatic disease. These findings support the need for close interval follow up and a low threshold for diagnostic biopsy in patients with extrapulmonary cancers and non-calcified pulmonary nodules. In smokers, such lesions should raise concern for lung cancer.

Leptin does not respond to 48 h fat deposition or mobilization in women

OBJECTIVE

To test the hypothesis that acute responses of plasma leptin concentration to energy balance manipulation are mediated by fat flux.

DESIGN

Ten healthy women aged 31-63 y, mass 48-113.5 kg, fat mass 8.5-62.5 kg, were studied for 3 days in a whole-body calorimeter on two occasions. After a control day (D1) during which energy balance was maintained, diet was manipulated to induce fat deposition (FD) or mobilization (FM) of 50 g/day for 2 days (D2 & D3). A difference totalling of 194+/-18.6 g fat was achieved between manipulations without significant effects on carbohydrate or protein balance. Fasting plasma leptin was measured on D2 and D4.

RESULTS

After the control day plasma leptin concentration averaged 19.01+/-9.8 ng/ml, and was found to be linearly related to body fat mass. After 2 days manipulation of fat balance, leptin concentrations were 21.4+/-10.3 ng/ml (FD) and 21.2+/-11.3 ng/ml (FM). There was no significant difference between treatments in either control day or postmanipulation leptin concentrations, nor did the treatments induce any differences in glucose or insulin concentration responses.

CONCLUSION

Although in states of energy balance leptin concentration is linearly related to fat mass, acute modulation of leptin concentration during energy imbalance is not mediated by fat flux.

The control of gene expression by regulated nuclear transport

Many proteins show distinct nuclear- and cytoplasmic-localization patterns. For proteins above the diffusion limit of the NPC, this localization is governed by the activity of NLSs and/or NESs contained in the protein. Structural modification of proteins can affect NLS and NES activities. Ligand binding, phosphorylation and proteolysis are each capable of modifying the nucleocytoplasmic distribution of proteins. In the case of transcription factors, control of these structural modifications affects access of the transcription factor to the chromatin. This management of cellular distribution, in turn, regulates gene expression.

Role of importin-beta in coupling Ran to downstream targets in microtubule assembly

The guanosine triphosphatase Ran stimulates assembly of microtubule asters and spindles in mitotic Xenopus egg extracts. A carboxyl-terminal region of the nuclear-mitotic apparatus protein (NuMA), a nuclear protein required for organizing mitotic spindle poles, mimics Ran's ability to induce asters. This NuMA fragment also specifically interacted with the nuclear transport factor, importin-beta. We show that importin-beta is an inhibitor of microtubule aster assembly in Xenopus egg extracts and that Ran regulates the interaction between importin-beta and NuMA. Importin-beta therefore links NuMA to regulation by Ran. This suggests that similar mechanisms regulate nuclear import during interphase and spindle assembly during mitosis.

An efficient color representation for image retrieval

A compact color descriptor and an efficient indexing method for this descriptor are presented. The target application is similarity retrieval in large image databases using color. Colors in a given region are clustered into a small number of representative colors. The feature descriptor consists of the representative colors and their percentages in the region. A similarity measure similar to the quadratic color histogram distance measure is defined for this descriptor. The representative colors can be indexed in the three-dimensional (3-D) color space thus avoiding the high-dimensional indexing problems associated with the traditional color histogram. For similarity retrieval, each representative color in the query image or region is used independently to find regions containing that color. The matches from all of the query colors are then combined to obtain the final retrievals. An efficient indexing scheme for fast retrieval is presented. Experimental results show that this compact descriptor is effective and compares favorably with the traditional color histogram in terms of overall computational complexity.

Selective disruption of nuclear import by a functional mutant nuclear transport carrier

p10/NTF2 is a nuclear transport carrier that mediates the uptake of cytoplasmic RanGDP into the nucleus. We constructed a point mutant of p10, D23A, that exhibited unexpected behavior both in digitonin-permeabilized and microinjected mammalian cells. D23A p10 was markedly more efficient than wild-type (wt) p10 at supporting Ran import, but simultaneously acted as a dominant-negative inhibitor of classical nuclear localization sequence (cNLS)-mediated nuclear import supported by karyopherins (Kaps) alpha and beta1. Binding studies indicated that these two nuclear transport carriers of different classes, p10 and Kap-beta1, compete for identical and/or overlapping binding sites at the nuclear pore complex (NPC) and that D23A p10 has an increased affinity relative to wt p10 and Kap-beta1 for these shared binding sites. Because of this increased affinity, D23A p10 is able to import its own cargo (RanGDP) more efficiently than wt p10, but Kap-beta1 can no longer compete efficiently for shared NPC docking sites, thus the import of cNLS cargo is inhibited. The competition of different nuclear carriers for shared NPC docking sites observed here predicts a dynamic equilibrium between multiple nuclear transport pathways inside the cell that could be easily shifted by a transient modification of one of the carriers.

Interactions between physical activity and diet in the regulation of body weight

The increasing worldwide prevalence of obesity suggests that there is a chronic positive energy balance. This situation implies poor coupling between energy intake and energy expenditure, but the contribution of each of these factors remains unclear. Epidemiological data suggests that physical activity has a role in the prevention of weight gain, although there is little evidence that it has a beneficial role in weight loss. High-fat diets have also been implicated, evidence from a variety of sources suggests that diets high in fat undermine appetite regulatory mechanisms. There has been much research to investigate the coupling between energy expenditure and energy intake in the short term in an attempt to elucidate some of the mechanisms involved. However, mechanisms regulating appetite are very complex, and it is currently unclear at which points physical activity and diet may have an influence.

The nuclear import of RCC1 requires a specific nuclear localization sequence receptor, karyopherin alpha3/Qip

RCC1 is the only known guanine nucleotide exchange factor for the small GTPase Ran and is normally found inside the nucleus bound to chromatin. In order to analyze in more detail the nuclear import of RCC1, we created a fusion construct in which four IgG binding domains of protein A were fused to the amino terminus of human RCC1 (pA-RCC1). Surprisingly, we found that neither Xenopus ovarian cytosol nor a mixture of recombinant import factors (karyopherin alpha2, karyopherin beta1, Ran, and p10/NTF2) were able to support the import of pA-RCC1 into the nuclei of digitonin-permeabilized cells. Both, in contrast, were capable of supporting the import of a construct containing another classical nuclear localization sequence (NLS), glutathione S-transferase-green fluorescent protein-NLS. Subsequently, we found that only one of the NLS receptors, karyopherin alpha3 (Kapalpha3/Qip), would support significant nuclear import of pA-RCC1 in permeabilized cells, while members of the other two main classes, Kapalpha1 and Kapalpha2, would not. Accordingly, in vitro binding studies revealed that only Kapalpha3 showed significant binding to RCC1 (unlike Kapalpha1 and Kapalpha2) and that this binding was dependent on the basic amino acids present in the RCC1 NLS. In addition to Kapalpha3, we found that the nuclear import of pA-RCC1 also required both karyopherin beta1 and Ran.

Dopamine modulates acute responses to cocaine, nicotine and ethanol in Drosophila

BACKGROUND

Drugs of abuse have a common property in mammals, which is their ability to facilitate the release of the neurotransmitter and neuromodulator dopamine in specific brain regions involved in reward and motivation. This increase in synaptic dopamine levels is believed to act as a positive reinforcer and to mediate some of the acute responses to drugs. The mechanisms by which dopamine regulates acute drug responses and addiction remain unknown.

RESULTS

We present evidence that dopamine plays a role in the responses of Drosophila to cocaine, nicotine or ethanol. We used a startle-induced negative geotaxis assay and a locomotor tracking system to measure the effect of psychostimulants on fly behavior. Using these assays, we show that acute responses to cocaine and nicotine are blunted by pharmacologically induced reductions in dopamine levels. Cocaine and nicotine showed a high degree of synergy in their effects, which is consistent with an action through convergent pathways. In addition, we found that dopamine is involved in the acute locomotor-activating effect, but not the sedating effect, of ethanol.

CONCLUSIONS

We show that in Drosophila, as in mammals, dopaminergic pathways play a role in modulating specific behavioral responses to cocaine, nicotine or ethanol. We therefore suggest that Drosophila can be used as a genetically tractable model system in which to study the mechanisms underlying behavioral responses to multiple drugs of abuse.

Contribution of a sedentary lifestyle and inactivity to the etiology of overweight and obesity: current evidence and research issues

PURPOSE

The etiology of overweight and obesity is clearly multifactorial, but ultimately it is determined by the long-term balance between energy intake and expenditure. This review will consider the effects on body weight and the risk of obesity of sedentary lifestyles, within the context of dietary habits.

METHODS

The data from ecological, cross-sectional, and prospective studies that have assessed physical activity and dietary intake and their relationship to body weight were reviewed.

RESULTS

Ecological analyses imply that the increase in the prevalence of obesity is more strongly related to lower levels of physical activity than higher energy intakes. However, there is a paucity of pertinent data from cross-sectional or prospective studies. There is some evidence that both a high proportion of dietary fat and low levels of physical activity may increase the likelihood of weight gain. However, even the most comprehensive studies are unable to account for more than a small proportion of the interindividual variance in weight gain, so it is difficult to usefully assess their relative importance. Furthermore, there are insufficient data that pertain to "sedentary lifestyles" to segregate any putative effect from a protective effect of exercise. All the data in this review is NHLBI Evidence category C.

CONCLUSIONS

This review provides clear evidence that low levels of physical activity are associated with an increased risk of weight gain and obesity. On balance, the evidence is suggestive of a causal link, but the experimental designs are too weak is provide conclusive evidence. The potential effect of interactions between diet and activity have largely been ignored. To make progress in this area, a number of key issues need to be resolved with regard to the methodology, study design, and statistical analysis of prospective epidemiological studies. In the meantime, data need to be drawn from other sources, particularly those studies designed to elucidate the mechanism of action of diet and physical activity in the etiology of obesity, to establish rational interventions to guide public health policies.

Getting across the nuclear pore complex

The nuclear pore complex (NPC) connects the cytoplasm and nucleus through the nuclear envelope and serves as the pipeline for moving material between the two compartments. Macromolecules that move through the NPC range in size from the very small (for example, ions and ATP) to the very large (for example, ribonucleoprotein particle complexes). Unlike translocation across other organelle membranes, proteins do not have to be unfolded to be transported through the NPC, and the NPC also routinely transports large, multicomponent substrates in both directions. This review focuses on current understanding of the different mechanisms by which macromolecules move across the NPC.

Engineered mutants in the switch II loop of Ran define the contribution made by key residues to the interaction with nuclear transport factor 2 (NTF2) and the role of this interaction in nuclear protein import

Nuclear protein import requires a precisely choreographed series of interactions between nuclear pore components and soluble factors such as importin-beta, Ran, and nuclear transport factor 2 (NTF2). We used the crystal structure of the GDPRan-NTF2 complex to design mutants in the switch II loop of Ran to probe the contribution of Lys71, Phe72 and Arg76 to this interaction. X-ray crystallography showed that the F72Y, F72W and R76E mutations did not introduce major structural changes into the mutant Ran. The GDP-bound form of the switch II mutants showed no detectable binding to NTF2, providing direct evidence that salt bridges involving Lys71 and Arg76 and burying Phe72 are all crucial for the interaction between Ran and NTF2. Nuclear protein accumulation in digitonin-permeabilzed cells was impaired with Ran mutants deficient in NTF2 binding, confirming that the NTF2-Ran interaction is required for efficient transport. We used mutants of the yeast Ran homologue Gsp1p to investigate the effect of the F72Y and R76E mutations in vivo. Although neither mutant was viable when integrated into the genome as a single copy, yeast mildly overexpressing the Gsp1p mutant corresponding Ran F72Y on a centromeric plasmid were viable, confirming that this mutant retained the essential properties of wild-type Ran. However, yeast expressing the Gsp1p mutant corresponding to R76E to comparable levels were not viable, although strains overexpressing the mutant to higher levels using an episomal 2micrometers plasmid were viable, indicating that the R76E mutation may also have interfered with other interactions made by Gsp1p.

The porous-coated anatomic total hip prosthesis, inserted without cement. A prospective study with a minimum of ten years of follow-up

One hundred consecutive primary total hip arthroplasties performed with use of a porous-coated anatomic total hip prosthesis, fixed without cement, in ninety-one patients were followed prospectively for a minimum of ten years. At the time of the most recent follow-up, twenty patients (twenty-three hips) had died and seventy-one patients (seventy-seven hips) were living. The average age of the living patients was sixty-six years (range, thirty-two to ninety-two years), and their average Harris hip score was 84 points (range, 33 to 100 points). Twelve percent (nine) of the seventy-seven hips were found to be associated with pain in the thigh when the patients were specifically questioned by the examiner. Eleven hips were revised during the follow-up period. Only the acetabular component was revised in six hips, only the femoral component was revised in one hip, and both the femoral and the acetabular components were revised in four hips. Of the ten acetabular revisions, one was performed because of acute dissociation of the component and eight, because of a combination of polyethylene wear, osteolysis, and loosening; the tenth acetabular revision consisted of exchange of the liner and curettage and bone-grafting of the osteolytic area. Of the five femoral revisions, two were performed because of loosening and three, because of extensive osteolysis of the proximal aspect of the femur. Including the revised components, twelve acetabular components and five femoral components had radiographic evidence of aseptic loosening. Acetabular osteolysis occurred in seventeen hips. Femoral osteolysis occurred in thirty-nine hips: in the proximal aspect of thirty-one hips, in the distal aspect of four, and in both the proximal and the distal aspect of four. The durability of the femoral fixation documented in this study is especially encouraging in view of the fact that this was our initial experience with devices fixed without cement and that a so-called first-generation femoral component was used. However, the study also demonstrated that not all acetabular components fixed without cement function well over the long term and that specific design considerations (adequate initial fixation, congruency between the liner and the shell, an optimum shell-liner capturing mechanism, and a smaller femoral head) are warranted.

Ran-dependent signal-mediated nuclear import does not require GTP hydrolysis by Ran

Nuclear import of classical nuclear localization sequence-containing proteins involves the assembly of an import complex at the cytoplasmic face of the nuclear pore complex (NPC) followed by movement of this complex through the NPC and release of the import substrate into the nuclear interior. This process has historically been thought to require nucleotide hydrolysis as a source of energy. We found, using hydrolysis-resistant GTP analogs and a mutant Ran unable to hydrolyze GTP, that transport of classical nuclear localization sequence containing substrate through the NPC and release of the substrate into the nucleus did not require hydrolysis of GTP by Ran. In fact, for movement of this type of import substrate into the nuclear interior we did not observe a requirement for hydrolysis of any nucleotide triphosphate. We did, however, find that a pool of free GTP (or its structural equivalent) must be added, probably because the GDP Ran that is added must be converted to GTP Ran during the import process. We found that a requirement for GTP hydrolysis can be restored to an import mixture consisting of recombinant import factors by the addition of RCC1, the Ran guanine nucleotide exchange factor.

The role of dual energy x-ray absorptiometry in aiding the diagnosis of pediatric osteogenesis imperfecta

The role of dual energy x-ray absorptiometry (DEXA) in the evaluation of the pediatric patient with multiple fractures has not been well established. We retrospectively examined the medical records of 45 patients who had presented to our institution with multiple fractures of unknown cause, who were not known to have osteogenesis imperfecta, and who had obtained DEXA as part of their evaluation. Of these, 26 patients had sufficient clinical data for inclusion in this study. Patients underwent DEXA of the anteroposterior spine and whole body. A z score was calculated to normalize the DEXA values for age. The diagnosis of osteogenesis imperfecta was correlated with the outcome of each DEXA scan to assess the validity of DEXA as a diagnostic tool. The DEXA of the anteroposterior spine had the highest sensitivity at 91.7%, while DEXA of the whole body had the highest specificity at 100.0%. Decreased bone mineral density may be associated with osteogenesis imperfecta, and DEXA is helpful in detecting low bone mineral density that may be missed on plain radiographs of children with milder forms of osteogenesis imperfecta.

The nuclear import factor p10 regulates the functional size of the nuclear pore complex during oogenesis

Previtellogenic, stage-1 Xenopus oocytes produce mainly 5S and tRNA, whereas vitellogenic oocytes, stages 2–6, synthesize predominantly 18S and 28S rRNA. Using nucleoplasmin-coated gold as a transport substrate, it was determined that the shift in synthesis from small to large RNAs during oogenesis is accompanied by an increase in both the rates of signal-mediated nuclear import and the functional size of nuclear pores. It was observed that, despite the reduction in transport capacity, gold still accumulated at the cytoplasmic surface of the pores in stage-1 oocytes. This suggested that transport in these cells is limited by translocation factors, rather than by cytoplasmic binding factors. Analysis of extracts prepared from stage-1 and vitellogenic oocytes revealed that the transport factor p10 is more abundant in stage-1 cells. Microinjection of purified p10 into stage-2 oocytes reduced the nuclear import of large gold particles to the level observed in stage-1 cells. It is concluded that p10 can modulate transport through the pores by regulating the functional size of the central transporter element.

Ethanol intoxication in Drosophila: Genetic and pharmacological evidence for regulation by the cAMP signaling pathway

Upon exposure to ethanol, Drosophila display behaviors that are similar to ethanol intoxication in rodents and humans. Using an inebriometer to measure ethanol-induced loss of postural control, we identified cheapdate, a mutant with enhanced sensitivity to ethanol. Genetic and molecular analyses revealed that cheapdate is an allele of the memory mutant amnesiac. amnesiac has been postulated to encode a neuropeptide that activates the cAMP pathway. Consistent with this, we find that enhanced ethanol sensitivity of cheapdate can be reversed by treatment with agents that increase cAMP levels or PKA activity. Conversely, genetic or pharmacological reduction in PKA activity results in increased sensitivity to ethanol. Taken together, our results provide functional evidence for the involvement of the cAMP signal transduction pathway in the behavioral response to intoxicating levels of ethanol.

Viral protein R regulates nuclear import of the HIV-1 pre-integration complex

Replication of human immunodeficiency virus type 1 (HIV-1) in non-dividing cells critically depends on import of the viral pre-integration complex into the nucleus. Genetic evidence suggests that viral protein R (Vpr) and matrix antigen (MA) are directly involved in the import process. An in vitro assay that reconstitutes nuclear import of HIV-1 pre-integration complexes in digitonin-permeabilized cells was used to demonstrate that Vpr is the key regulator of the viral nuclear import process. Mutant HIV-1 pre-integration complexes that lack Vpr failed to be imported in vitro, whereas mutants that lack a functional MA nuclear localization sequence (NLS) were only partially defective. Strikingly, the import defect of the Vpr- mutant was rescued when recombinant Vpr was re-added. In addition, import of Vpr- virus was rescued by adding the cytosol of HeLa cells, where HIV-1 replication had been shown to be Vpr-independent. In a solution binding assay, Vpr associated with karyopherin alpha, a cellular receptor for NLSs. This association increased the affinity of karyopherin alpha for basic-type NLSs, including that of MA, thus explaining the positive effect of Vpr on nuclear import of the HIV-1 pre-integration complex and BSA-NLS conjugates. These results identify the biochemical mechanism of Vpr function in transport of the viral pre-integration complex to, and across, the nuclear membrane.