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1.
Int J Endocrinol ; 2019: 7251010, 2019.
Article in English | MEDLINE | ID: mdl-31320899

ABSTRACT

PURPOSE: The prevalence of adrenal insufficiency (AI) in patients with decompensated liver cirrhosis is unknown. Because these patients have lower levels of cortisol-binding carrier proteins, their total serum cortisol (TSC) correlates poorly with free serum cortisol (FC). Salivary cortisol (SaC) correlates better with FC. We aimed to establish SaC thresholds for AI for the 250 µg intravenous ACTH test and to estimate the prevalence of AI in noncritically ill cirrhotic patients. METHODS: We included 39 patients with decompensated cirrhosis, 39 patients with known AI, and 45 healthy volunteers. After subjects fasted ≥8 hours, serum and saliva samples were collected for determinations of TSC and SaC at baseline 0'(T0) and at 30-minute intervals after intravenous administration of 250 µg ACTH [30'(T30), 60'(T60), and 90'(T90)]. RESULTS: Based on the findings in healthy subjects and patients with known AI, we defined AI in cirrhotic patients as SaC-T0< 0.08 µg/dL (2.2 nmol/L), SaC-T60 < 1.43 µg/dl (39.5 nmol/L), or ΔSaC<1 µg/dl (27.6 nmol/L). We compared AI determination in cirrhotic patients with the ACTH test using these SaC thresholds versus established TSC thresholds (TSC-T0< 9 µg/dl [248 nmol/L], TSC-T60 < 18 µg/dl [497 nmol/L], or ΔTSC<9 µg/dl [248 nmol/L]). SaC correlated well with TSC. The prevalence of AI in cirrhotic patients was higher when determined by TSC (48.7%) than by SaC (30.8%); however, this difference did not reach statistical significance. AI was associated with sex, cirrhosis etiology, and Child-Pugh classification. CONCLUSIONS: Measuring SaC was more accurate than TSC in the ACTH stimulation test. Measuring TSC overestimated the prevalence of AI in noncritically ill cirrhotic patients.

2.
Aging (Albany NY) ; 11(5): 1510-1523, 2019 03 14.
Article in English | MEDLINE | ID: mdl-30875333

ABSTRACT

Aging is a degenerative process in which genome instability plays a crucial role. To gain insight into the link between organismal aging and DNA repair capacity, we analyzed DNA double-strand break (DSB) resolution efficiency in human mammary epithelial cells from 12 healthy donors of young and old ages. The frequency of DSBs was measured by quantifying the number of γH2AX foci before and after 1Gy of γ-rays and it was higher in cells from aged donors (ADs) at all times analyzed. At 24 hours after irradiation, ADs retained a significantly higher frequency of residual DSBs than young donors (YDs), which had already reached values close to basal levels. The kinetics of DSB induction and disappearance showed that cells from ADs and YDs repair DSBs with similar speed, although analysis of early times after irradiation indicate that a repair defect may lie within the firing of the DNA repair machinery in AD cells. Indeed, using a mathematical model we calculated a constant factor of delay affecting aged human epithelial cells repair kinetics. This defect manifests with the accumulation of DSBs that might eventually undergo illegitimate repair, thus posing a relevant threat to the maintenance of genome integrity in older individuals.


Subject(s)
DNA Repair/physiology , Epithelial Cells/physiology , Histones/metabolism , Mammary Glands, Human/cytology , Adolescent , Adult , Aged , Breast Neoplasms/radiotherapy , Cells, Cultured , DNA Breaks, Double-Stranded , Female , Gene Expression Regulation , Histones/genetics , Humans , Middle Aged , Young Adult
3.
BMC Nephrol ; 18(1): 49, 2017 02 03.
Article in English | MEDLINE | ID: mdl-28158993

ABSTRACT

BACKGROUND: Minimal change disease (MCD) and primary focal segmental glomerulosclerosis (FSGS) are glomerular diseases characterized by nephrotic syndrome. Their diagnosis requires a renal biopsy, but it is an invasive procedure with potential complications. In a small biopsy sample, where only normal glomeruli are observed, FSGS cannot be differentiated from MCD. The correct diagnosis is crucial to an effective treatment, as MCD is normally responsive to steroid therapy, whereas FSGS is usually resistant. The purpose of our study was to discover and validate novel early urinary biomarkers capable to differentiate between MCD and FSGS. METHODS: Forty-nine patients biopsy-diagnosed of MCD and primary FSGS were randomly subdivided into a training set (10 MCD, 11 FSGS) and a validation set (14 MCD, 14 FSGS). The urinary proteome of the training set was analyzed by two-dimensional differential gel electrophoresis coupled with mass spectrometry. The proteins identified were quantified by enzyme-linked immunosorbent assay in urine samples from the validation set. RESULTS: Urinary concentration of alpha-1 antitrypsin, transferrin, histatin-3 and 39S ribosomal protein L17 was decreased and calretinin was increased in FSGS compared to MCD. These proteins were used to build a decision tree capable to predict patient's pathology. CONCLUSIONS: This preliminary study suggests a group of urinary proteins as possible non-invasive biomarkers with potential value in the differential diagnosis of MCD and FSGS. These biomarkers would reduce the number of misdiagnoses, avoiding unnecessary or inadequate treatments.


Subject(s)
Glomerulosclerosis, Focal Segmental/urine , Nephrosis, Lipoid/urine , Adult , Aged , Biomarkers/urine , Calbindin 2/urine , Decision Trees , Electrophoresis, Gel, Two-Dimensional , Enzyme-Linked Immunosorbent Assay , Female , Glomerulosclerosis, Focal Segmental/diagnosis , Glomerulosclerosis, Focal Segmental/pathology , Histatins/urine , Humans , Male , Mass Spectrometry , Middle Aged , Nephrosis, Lipoid/diagnosis , Nephrosis, Lipoid/pathology , Proteomics , Reproducibility of Results , Ribosomal Proteins/urine , Transferrin/urine , alpha 1-Antitrypsin/urine
4.
Biomed Res Int ; 2014: 269402, 2014.
Article in English | MEDLINE | ID: mdl-24575403

ABSTRACT

This study aimed to provide novel insights into the gastrointestinal microbial diversity from different gastrointestinal locations in weaning piglets using PCR-restriction fragment length polymorphism (PCR-RFLP). Additionally, the effect of different feed additives was analyzed. Thirty-two piglets were fed with four different diets: a control group and three enriched diets, with avilamycin, sodium butyrate, and a plant extract mixture. Digesta samples were collected from eight different gastrointestinal segments of each animal and the bacterial population was analysed by a PCR-RFLP technique that uses 16S rDNA gene sequences. Bacterial diversity was assessed by calculating the number of bands and the Shannon-Weaver index. Dendrograms were constructed to estimate the similarity of bacterial populations. A higher bacterial diversity was detected in large intestine compared to small intestine. Among diets, the most relevant microbial diversity differences were found between sodium butyrate and plant extract mixture. Proximal jejunum, ileum, and proximal colon were identified as those segments that could be representative of microbial diversity in pig gut. Results indicate that PCR-RFLP technique allowed detecting modifications on the gastrointestinal microbial ecology in pigs fed with different additives, such as increased biodiversity by sodium butyrate in feed.


Subject(s)
Feeding Behavior/drug effects , Food Additives/pharmacology , Gastrointestinal Tract/microbiology , Weaning , Animals , Bacteria/drug effects , Biodiversity , Colony Count, Microbial , Diet , Gastrointestinal Tract/drug effects , Phylogeny , Polymerase Chain Reaction , Polymorphism, Restriction Fragment Length , Sus scrofa
5.
Proc Natl Acad Sci U S A ; 109(39): E2587-94, 2012 Sep 25.
Article in English | MEDLINE | ID: mdl-22949647

ABSTRACT

Fluorescence live-cell imaging has temporally resolved the conserved choreography of more than 30 proteins involved in clathrin and actin-mediated endocytic budding from the plasma membrane. However, the resolution of these studies is insufficient to unveil how the endocytic machinery actually drives membrane deformation in vivo. In this study, we use quantitative immuno-EM to introduce the temporal dimension to the ultrastructural analysis of membrane budding and define changes in the topography of the lipid bilayer coupled to the dynamics of endocytic proteins with unprecedented spatiotemporal resolution. Using this approach, we frame the emergence of membrane curvature with respect to the recruitment of endocytic factors and show that constriction of the invaginations correlates with translocation of membrane-sculpting proteins. Furthermore, we show that initial bending of the plasma membrane is independent of actin and clathrin polymerization and precedes building of an actin cap branched by the Arp2/3 complex. Finally, our data indicate that constriction and additional elongation of the endocytic profiles require the mechanochemical activity of the myosins-I. Altogether, this work provides major insights into the molecular mechanisms driving membrane deformation in a cellular context.


Subject(s)
Actin-Related Protein 2-3 Complex/metabolism , Cell Membrane/metabolism , Endocytosis/physiology , Myosin Type I/metabolism , Saccharomyces cerevisiae Proteins/metabolism , Saccharomyces cerevisiae/metabolism , Actin-Related Protein 2-3 Complex/genetics , Actin-Related Protein 2-3 Complex/ultrastructure , Cell Membrane/genetics , Cell Membrane/ultrastructure , Myosin Type I/genetics , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/ultrastructure , Saccharomyces cerevisiae Proteins/genetics
6.
Tob Induc Dis ; 10(1): 7, 2012 May 21.
Article in English | MEDLINE | ID: mdl-22613769

ABSTRACT

BACKGROUND: Smoking has been linked to low-grade systemic inflammation, a known risk factor for disease. This state is reflected in elevated white blood cell (WBC) count. OBJECTIVE: We analyzed the relationship between WBC count and smoking in healthy men and women across several age ranges who underwent preventive medical check-ups in the workplace. We also analysed the relationship between smoking and lung function. METHODS: Cross-sectional descriptive study in 163 459 men and 59 382 women aged between 16 and 70 years. Data analysed were smoking status, WBC count, and spirometry readings. RESULTS: Total WBC showed higher counts in both male and female smokers, around 1000 to 1300 cell/ml (t test, P < 0.001). Forced expiratory volume in 1 second (FEV1%) was higher in nonsmokers for both sexes between 25 to 54 years (t test, P < 0.001). Analysis of covariance showed a multiple variable effect of age, sex, smoking status, body mass index on WBC count. The relationship between WBC blood count and smoking status was confirmed after the sample was stratified for these variables. Smokers with airway obstruction measured by FEV1% were found to have higher WBC counts, in comparison to smokers with a normal FEV1% among similar age and BMI groups. CONCLUSIONS: Smoking increases WBC count and affects lung function. The effects are evident across a wide age range, underlining the importance of initiating preventive measures as soon as an individual begins to smoke.

7.
Kidney Blood Press Res ; 35(5): 314-25, 2012.
Article in English | MEDLINE | ID: mdl-22399069

ABSTRACT

BACKGROUND/AIMS: Glomerular kidney disease (GKD) is suspected in patients based on proteinuria, but its diagnosis relies primarily on renal biopsy. We used urine peptide profiling as a noninvasive means to link GKD-associated changes to each glomerular entity. METHODS: Urinary peptide profiles of 60 biopsy-proven glomerular patients and 14 controls were analyzed by combining magnetic bead peptide enrichment, MALDI-TOF MS analysis, and ClinProTools v2.0 to select differential peptides. Tentative identification of the differential peptides was carried out by HPLC-MS/MS. RESULTS: The HPLC-MS/MS results suggest that uromodulin (UMOD; m/z: 1682, 1898 and 1913) and α(1)-antitrypsin (A1AT; m/z: 1945, 2392 and 2505) are differentially expressed urinary peptides that distinguish between GKD patients and healthy subjects. Low UMOD and high A1AT peptide abundance was observed in 80-92% of patients with GKD. Proliferative forms of GKD were distinguished from nonproliferative forms, based on a combination of UMOD and A1AT peptides. Nonproliferative forms correlated with higher A1AT peptide levels - focal segmental glomerulosclerosis was linked more closely to high levels of the m/z 1945 peptide than minimal change disease. CONCLUSION: We describe a workflow - urinary peptide profiling coupled with histological findings - that can be used to distinguish GKD accurately and noninvasively, particularly its nonproliferative forms.


Subject(s)
Glomerulonephritis/diagnosis , Glomerulonephritis/urine , Protein Array Analysis/methods , Uromodulin/urine , alpha 1-Antitrypsin/urine , Adult , Biomarkers/analysis , Biomarkers/urine , Biopsy , Creatinine/blood , Diagnosis, Differential , Female , Glomerulonephritis/pathology , Humans , Kidney/pathology , Male , Middle Aged , Placental Lactogen , Protein Array Analysis/standards , Proteinuria/diagnosis , Proteinuria/pathology , Proteinuria/urine , ROC Curve , Reference Values , Reproducibility of Results , Sequence Analysis, Protein , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Uromodulin/analysis , Young Adult , alpha 1-Antitrypsin/analysis
8.
Int J Biometeorol ; 56(6): 1167-71, 2012 Nov.
Article in English | MEDLINE | ID: mdl-21904808

ABSTRACT

The objective of the present work was to elucidate the potential relationship between Mycoplasma hyopneumoniae infection and seroconversion dynamics and climatological conditions in four groups of pigs from the same farm born in different seasons of the year. Nasal swabs and blood samples were taken from 184 pigs at 1, 3, 6, 9, 12, 15, 18, 22 and 25 (slaughter age) weeks of age. Outside climatologic parameters, including temperature (°C), relative humidity (%), precipitation (l/m(2)) and wind speed (m/s) were recorded weekly from January 2003 to June 2004. Percentage of nPCR detection of M. hyopneumoniae in nasal swabs was associated significantly with the weekly precipitation rate [P = 0.0018, OR = 1.31 (IC = 1.11-1.55)]; the higher the precipitation rate, the higher the probability of being M. hyopneumoniae nPCR-positive. On the other hand, the percentage of seropositive pigs had a significant association with mean weekly temperature rate [P = 0.0012, OR = 0.89 [IC = 0.84-0.95]); the lower the temperature, the higher the probability of being M. hyopneumoniae seropositive. Animals born in autumn (when higher precipitations rates were recorded), entering finishing units in winter (when lower temperatures were recorded), and reaching slaughter in spring, had the highest probability of being infected by M. hyopneumoniae and the highest probability of being M. hyopneumoniae seropositive.


Subject(s)
Mycoplasma hyopneumoniae , Pneumonia of Swine, Mycoplasmal/epidemiology , Weather , Animals , DNA, Bacterial/analysis , Pneumonia of Swine, Mycoplasmal/blood , Pneumonia of Swine, Mycoplasmal/microbiology , Spain/epidemiology , Swine
9.
Nephrol Dial Transplant ; 26(12): 3914-23, 2011 Dec.
Article in English | MEDLINE | ID: mdl-21414970

ABSTRACT

BACKGROUND: Podocyte proteins are involved in the pathogenesis of glomerular kidney disease (GKD). However, there is little information on messenger RNA (mRNA) expression patterns of B7-1 and NPHS1 in urinary sediment of patients with GKD. The objective of this study was to analyse the gene expression of B7-1 in urinary sediment and correlate it with the expression of podocyte-specific genes in patients with GKD. METHODS: Adult patients with proliferative and non-proliferative GKD, proteinuria and stable renal function, were included. A group of healthy subjects was used to determine normal levels of urinary markers and to obtain reference RNA. Biochemical, clinical and experimental procedures included measurement of creatinine level and total urinary protein, renal biopsy, identification of urinary podocytes, gene expression analysis of B7-1, NPHS1, NPHS2 and SyNPO genes and urinary B7-1 protein analysis by enzyme-linked immunosorbent assay. RESULTS: Between June 2006 and November 2009, 69 patients with GKD (median age: 46 ± 15 years, 64% men) and 14 healthy subjects (median age: 34 ± 12 years, 43% men) were included. In both groups, urinary mRNA levels of B7-1 and NPHS1 were significantly higher in patients with GKD compared to healthy subjects (P = 0.050 and P = 0.008, respectively). Regarding GKD subtypes, patients with focal segmental glomerulosclerosis (FSGS), but not patients with minimal change disease (MCD), had a significantly higher mRNA expression of B7-1 and NPHS1 than healthy subjects (P = 0.012 and P = 0.030, respectively). Patients with MCD had a significantly lower NPHS1 mRNA expression than patients with FSGS (P = 0.012). The B7-1:NPHS1 urinary mRNA ratio was significantly higher in patients with MCD compared with patients with FSGS (P = 0.027). CONCLUSION: mRNA expression analysis of B7-1 and NPHS1 in urinary sediment may be useful to differentiate between different histologic subtypes of GKD, particularly between MCD and FSGS.


Subject(s)
Glomerulosclerosis, Focal Segmental/genetics , Glomerulosclerosis, Focal Segmental/urine , Inducible T-Cell Co-Stimulator Ligand/genetics , Inducible T-Cell Co-Stimulator Ligand/urine , Membrane Proteins/genetics , Membrane Proteins/urine , Nephrosis, Lipoid/genetics , Nephrosis, Lipoid/urine , RNA, Messenger/biosynthesis , Adult , Diagnosis, Differential , Female , Glomerulosclerosis, Focal Segmental/diagnosis , Humans , Male , Middle Aged , Nephrosis, Lipoid/diagnosis , Podocytes , Prospective Studies
10.
Vet Microbiol ; 149(3-4): 352-7, 2011 May 05.
Article in English | MEDLINE | ID: mdl-21215535

ABSTRACT

Post-weaning multisystemic wasting syndrome (PMWS) is a worldwide distributed disease of multifactorial origin and porcine circovirus type 2 (PCV2) has been identified as its essential infectious aetiology. Pig genetic background has been pointed to influence disease expression. In the present study, three different boar lines, namely A (100% Pietrain), B (50% Large White × 50% Pietrain) and C (25% Large White × 75% Duroc), were used to inseminate sows from the same genetic line (37.5% Large White × 37.5% Duroc × 25% Landrace) located on two PMWS-affected farms (farm-1 and farm-2). The PMWS clinical expression of their offspring was studied from weaning to slaughter, evaluating three parameters: total post-weaning mortality (PWM), PWM associated to PMWS (PMWS-PWM) and body weight (BW) evolution. The effect of other variables potentially related with PMWS, including sow and piglet PCV2 exposure, sow parity, piglet gender and piglet BW at weaning, were also considered in the study design. Overall, a total of 6.5% PWM and 4.3% PMWS-PWM occurred in the monitored farms. Pigs from boar line C showed the highest PWM (16.3%) and PMWS-PWM (12.4%), and the lowest BW; pigs from boar line A showed the lowest PWM (1.8%) and the highest BW. Furthermore, PWM was also higher in piglets from farm-2 and from multiparous sows. In farm-2, PMWS-PWM was higher in piglets from multiparous sows. Finally, BW was influenced by interactions between genetics and both farm and pig age, and was lower in piglets from farm-2. This study represents a consistent observation of the genetic background effect on PMWS clinical expression under field conditions.


Subject(s)
Porcine Postweaning Multisystemic Wasting Syndrome/genetics , Porcine Postweaning Multisystemic Wasting Syndrome/mortality , Swine/genetics , Animals , Circoviridae Infections/genetics , Circoviridae Infections/veterinary , Circoviridae Infections/virology , Circovirus/pathogenicity , Female , Logistic Models , Male , Porcine Postweaning Multisystemic Wasting Syndrome/virology , Weaning
11.
Can J Vet Res ; 73(4): 308-12, 2009 Oct.
Article in English | MEDLINE | ID: mdl-20046634

ABSTRACT

The objective of this study was to evaluate the prevalence of infection with porcine circovirus-2 (PCV-2) and porcine reproductive and respiratory syndrome virus (PRRSV) through a longitudinal study in an integrated swine production system (7 farms) experiencing postweaning multisystemic wasting syndrome (PMWS). Risk factors for PCV-2 infection and for PCV-2 and PRRSV coinfection were also evaluated. Fifteen sows from each herd and 4 non-cross-fostered piglets from each sow were randomly selected at farrowing and ear-tagged at birth. Serum samples were analyzed for antibodies to PCV-2 and for detection of the PCV-2 and PRRSV genomes. Statistical analyses involved 2 approaches. The 1st approach characterized the dynamics of PCV-2 infection and their relationship with PRRSV infection. The 2nd approach analyzed the probability of being infected by PCV-2 or by both PCV-2 and PRRSV through a generalized linear mixed model incorporating sow and farm characteristics. At the 1st sampling time (1 wk of age), there was a significant relationship between sow PCV-2 infection and piglet PCV-2 infection (P < 0.0001). The risk of PCV-2 and PRRSV coinfection was 1.85 times greater in piglets from a sow with low titers of PCV-2 antibodies than in piglets from sows with medium to high titers (P = 0.03) and was 2.54, 2.40, and 2.02 times greater, respectively, in piglets from primiparous sows, PCV-2-infected sows, and farms in an area of high pig density than in piglets from sows of higher parity (P = 0.004), noninfected sows (P = 0.04), and farms in a low-density area (P = 0.09).


Subject(s)
Circoviridae Infections/epidemiology , Circoviridae Infections/veterinary , Circovirus/isolation & purification , Porcine Postweaning Multisystemic Wasting Syndrome/epidemiology , Porcine Reproductive and Respiratory Syndrome/epidemiology , Porcine respiratory and reproductive syndrome virus/isolation & purification , Animals , Animals, Newborn , Antibodies, Viral/blood , Chi-Square Distribution , Circoviridae Infections/immunology , Circoviridae Infections/virology , Circovirus/genetics , Circovirus/immunology , Female , Immunoenzyme Techniques/veterinary , Linear Models , Longitudinal Studies , Polymerase Chain Reaction/veterinary , Porcine Postweaning Multisystemic Wasting Syndrome/immunology , Porcine Postweaning Multisystemic Wasting Syndrome/virology , Porcine Reproductive and Respiratory Syndrome/immunology , Porcine Reproductive and Respiratory Syndrome/virology , Porcine respiratory and reproductive syndrome virus/genetics , Porcine respiratory and reproductive syndrome virus/immunology , Pregnancy , Prevalence , RNA, Viral/chemistry , RNA, Viral/genetics , Swine
12.
J Clin Oncol ; 23(25): 6063-71, 2005 Sep 01.
Article in English | MEDLINE | ID: mdl-16087949

ABSTRACT

PURPOSE: To determine the association between depression and survival among cancer patients at 1, 3, and 5 years after stem-cell transplantation (SCT). PATIENTS AND METHODS: This was a prospective cohort study of 199 hematologic cancer patients who survived longer than 90 days after SCT and who were recruited in a University-based hospital between July 1994 and August 1997. Patients received a psychiatric assessment at four consecutive time points during hospitalization for SCT, yielding a total of 781 interviews. Depression diagnoses were determined on the basis of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. RESULTS: Eighteen (9.0%) and 17 patients (8.5%) met criteria for major and minor depression, respectively. Multivariate Cox regression models found major depression to be predictive of higher 1-year (hazard ratio [HR], 2.59; 95% CI, 1.21 to 5.53; P = .014) and 3-year mortality (HR, 2.04; 95% CI, 1.03 to 4.02; P = .041) but not 5-year mortality (HR, 1.48; 95% CI, 0.76 to 2.87; P = .249). Minor depression had no effect on any mortality outcome. Other multivariate significant predictors of higher mortality were higher regimen toxicity in the 1-, 3-, and 5-year models; older age and acute lymphoblastic leukemia in the 3- and 5-year models; chronic myelogenous leukemia in the 3-year model; and lower functional status and intermediate/higher risk status in the 5-year model. Use of peripheral-blood stem cells predicted lower mortality in the 5-year model. CONCLUSION: After adjusting for multiple factors, major depression predicted higher 1- and 3-year mortality among cancer patients after SCT, underscoring the importance of adequate diagnosis and treatment of major depression.


Subject(s)
Depressive Disorder, Major/complications , Hematologic Neoplasms/psychology , Hematologic Neoplasms/therapy , Hematopoietic Stem Cell Transplantation/psychology , Adolescent , Adult , Aged , Diagnostic and Statistical Manual of Mental Disorders , Female , Humans , Male , Middle Aged , Prognosis , Prospective Studies , Survival Analysis
13.
Stat Med ; 22(3): 409-25, 2003 Feb 15.
Article in English | MEDLINE | ID: mdl-12529872

ABSTRACT

Interval-censored observations of a response variable are a common occurrence in medical studies, and usually result when the response is the elapsed time until some event whose occurrence is periodically monitored. In this paper we consider a multivariate regression setting in which the explanatory variable is interval censored. Use of an ad hoc method of analysis for such data, such as taking the midpoint of the interval-censored covariate and applying ordinary least-squares, is not in general valid. We develop a likelihood approach, together with a two-step conditional algorithm, to jointly estimate the regression coefficients as well as the marginal distribution of the covariate. The resulting estimators are asymptotically normal. The performance of the method is assessed via simulations, and illustrated using data from a recent HIV/AIDS clinical trial to assess the association between waiting time between indinavir failure and subsequent viral load at enrolment. Extensions of the procedure to other parametric distributions are discussed.


Subject(s)
Linear Models , Statistics as Topic/methods , Adult , Computer Simulation , HIV/growth & development , HIV/metabolism , HIV Infections/drug therapy , HIV Infections/virology , HIV Protease Inhibitors/therapeutic use , Humans , Indinavir/therapeutic use , Likelihood Functions , Middle Aged , Multivariate Analysis , Recurrence , Viral Load
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