Biomedical subjects

H L Weiss

Publications and source records attributed to H L Weiss.

At least 19 recordsLinked to original sources

PubMed2005

Hormone receptor status of a contralateral breast cancer is independent of the receptor status of the first primary in patients not receiving adjuvant tamoxifen.

PURPOSE: To determine whether the hormone receptor status of the primary breast cancer (PBC) is predictive of the hormone receptor status of the subsequent contralateral breast cancer (CBC). PATIENTS AND METHODS: We identified patients in our database with known estrogen receptor (ER; n = 193) and/or progesterone receptor (PgR; n = 178) status in their PBC and in their subsequent CBC. One hundred twenty-six of these patients had received no adjuvant therapy, 34 had received adjuvant tamoxifen, and 33 had received adjuvant chemotherapy alone. The median interval between the first diagnosis of PBC and the development of the subsequent CBC was 3 years. ER and PgR assays were assessed biochemically in two central reference laboratories using identical quality-controlled ligand-binding methods. RESULTS: Among systemically untreated patients (n = 126), 88% of patients with ER-positive PBC and 75% of patients with ER-negative PBC developed an ER-positive CBC (P = .11). Among the tamoxifen-treated patients, those with an ER-positive PBC were almost equally likely to develop an ER-positive (47%) or ER-negative (53%) CBC (P = .99). PgR status was similar. In the untreated group (n = 112), 59% of patients with a PgR-positive PBC and 66% with a PgR-negative PBC developed a PgR-positive CBC (P = .48). Among tamoxifen-treated patients (n = 33), 50% of patients with a PgR-positive PBC versus 27% of patients with a PgR-negative PBC developed a PgR-positive CBC (P = .28). CONCLUSION: ER and PgR status of the primary tumor does not predict the hormone receptor status of the subsequent CBC in the absence of selective pressure of adjuvant therapy. Thus, other reasons should be considered to clarify the failure of tamoxifen to reduce the incidence of CBC in patients with a receptor-negative PBC.

Aged↗

PubMed2001

Phase specific analysis of herpes zoster associated pain data: a new statistical approach.

Herpes zoster or shingles is a frequent occurrence in both elderly individuals and immunocompromised hosts. The pain associated with herpes zoster is the most debilitating complication of the disease. It can be described as acute pain and post-herpetic neuralgia or zoster associated pain (ZAP). The latter definition encompasses pain from the onset of disease through its resolution and provides a convenient analytic tool for evaluation of antiviral therapy. A heuristic examination of ZAP historical data suggests the existence of three phases of pain resolution: the acute, subacute and chronic phases. The subacute and chronic phases comprise the post-herpetic neuralgia (PHN) stage. Common analytic methods, such as a Kaplan-Meier survival function or a Cox's model, have been used to assess the pain. However, such approaches do not adequately allow for phase comparison. Notably, in the clinical trial setting the comparison of specific treatment effects on the latter stages of pain are of the greatest medical relevance since this is the most debilitating phase of the illness. In order to incorporate the phase-specific information in the modelling of time to cessation of ZAP, we assumed the hazard function was a stepwise constant. Utilizing the full likelihood function, we obtained the maximum likelihood estimate for the transition times (that is, change-points), and other parameters of medical importance. The standard error of the change-point estimates were obtained through a bootstrapping method. The asymptotic properties of the parameter estimates are also discussed. Hence, the rates of pain resolution across all phases can be examined in order to precisely define the existence of multiple phases. In addition, the covariates effect can be examined across phases and populations, thereby allowing us to translate potential efficacy of a standard therapy to different populations. These results can be utilized in the design of clinical trials or in targeting the outcome for a specific phase while controlling for the effect of other variables.

Acute Disease↗

PubMed2001

Risk factors for acquisition of hepatitis C virus infection: a case series and potential implications for disease surveillance.

BACKGROUND: Transmission of hepatitis C virus (HCV) is strongly associated with use of contaminated blood products and injection drugs. Other "non-parental" modes of transmission including sexual activity have been increasingly recognized. We examined risk factors for acquiring HCV in patients who were referred to two tertiary care centers and enrolled in an antiviral therapy protocol. METHODS: Interviews of 148 patients were conducted apart from their physician evaluation using a structured questionnaire covering demographics and risk factors for HCV acquisition. RESULTS: Risk factors (blood products, injection/intranasal drugs, razor blades/ toothbrushes, body/ear piercing, occupational exposure, sexual activity) were identified in 141 (95.3%) of participants; 23 (15.5%) had one (most frequently blood or drug exposure), 41 (27.7%) had two, and 84 (53.4%) had more than two risk factors. No patient reported sexual activity as a sole risk factor. Body piercing accounted for a high number of exposures in women. Men were more likely to have exposure to street drugs but less exposure to blood products than women. Blood product exposure was less common in younger than older HCV patients. CONCLUSION: One and often multiple risk factors could be identified in nearly all HCV-infected patients seen in a referral practice. None named sexual transmission as the sole risk factor. The development of a more complete profile of factors contributing to transmission of HCV infection may assist in clinical and preventive efforts. The recognition of the potential presence of multiple risk factors may have important implications in the approach to HCV surveillance, and particularly the use of hierarchical algorithms in the study of risk factors.

Acute Disease↗

PubMed2001

Bayesian monitoring of a phase 2 chemoprevention trial in high-risk cohorts for prostate cancer.

The objective of phase 2 cancer chemoprevention trials is to evaluate whether a chemopreventive agent will cause significant modulation of intermediate endpoint biomarkers (IEB) in patients at high risk for the disease. A phase 2 chemoprevention trial of 4-hydroxyphenyl retinamide (4-HPR) versus placebo was conducted in men with a histologic diagnosis of early prostate cancer and scheduled to have radical prostatectomy. A Bayesian monitoring method was used to sequentially monitor this trial for evidence of biological activity or ineffectiveness based on a single IEB variable. Different prior distributions were used and posterior distributions were obtained to calculate the probability that treatment differences are greater than or less than a predetermined clinically significant effect. The interim analysis of transforming growth factor-alpha expression indicated a high probability of insufficient biological activity of 4-HPR on this IEB. This study demonstrates the potential utility of Bayesian methods in the decision-making process in the conduct of phase 2 chemoprevention trials.

Anticarcinogenic Agents↗

PubMed2001

Molecular biomarkers for breast cancer prognosis: coexpression of c-erbB-2 and p53.

OBJECTIVE: To assess the prognostic significance of molecular biomarkers, particularly c-erbB-2 and p53, through study of prospective clinical data and archival breast cancer tissues for women accrued to the Alabama Breast Cancer Project. SUMMARY BACKGROUND DATA: Defining molecular abnormalities in breast cancer is an important strategy for early detection, assessment of prognosis, and treatment selection. Evidence is strong that selective biomarkers, including c-erbB-2 and p53, have prognostic significance in breast cancer. Few studies have analyzed the prognostic significance of coexpression of biomarkers. METHODS: Study patients were those accrued to the Alabama Breast Cancer Project (1975-1978) who had archival breast cancer tissues available for analysis. Criteria for entrance into the Alabama Breast Cancer Project were T1-3 breast cancer with M0 status. Age, nodal status, and histologic grade were also documented. Patients were randomized to radical versus modified radical mastectomy, and node-positive patients were also randomized to adjuvant chemotherapy (cyclophosphamide, methotrexate, and 5-fluorouracil [CMF]) versus melphalan. Archival breast cancer tissues were studied for c-erbB-2, TGF-alpha, p53, cathepsin D, bcl-2, and estrogen and progesterone receptor expression using immunohistochemistry. Survival curves were developed using the Kaplan-Meier method. Univariate analysis was performed using the log-rank test, multivariate analysis using a rank regression model. RESULTS: Three hundred eleven patients were accrued to the Alabama Breast Cancer Project, and paraffin-embedded breast cancer tissues for 90 patients were available for immunohistochemical analysis of molecular biomarkers. Univariate analysis showed nodal status, c-erbB-2 expression, and p53 expression to have prognostic significance. Coexpression of c-erbB-2 and p53 was also found to have prognostic significance by the log-rank test. Multivariate analysis showed T stage, nodal status, c-erbB-2 expression, and p53 expression to have independent prognostic significance. CONCLUSIONS: These data suggest that c-erbB-2 and p53 expression in breast cancer have prognostic significance. After median follow-up of 16 years, coexpression of c-erbB-2 and p53 may have more prognostic significance than traditional prognostic factors such as T stage and nodal status. Prospective study of large numbers of patients with breast cancer is encouraged to validate these findings.

Aged↗

PubMed2001

Molecular differences in mucoepidermoid carcinoma and adenoid cystic carcinoma of the major salivary glands.

OBJECTIVE/HYPOTHESIS: Mucoepidermoid carcinoma (MEC) and adenoid cystic carcinoma (ACC), the most common malignancies of the major salivary glands, are clinically and pathologically different. To determine whether MEC and ACC have different molecular characteristics, we examined the expression of erbB-2, erbB-3, epidermal growth factor receptor (EGFR), and transforming growth factor-alpha (TGF-alpha), important molecular features in other malignancies. STUDY DESIGN/METHODS: Archival tissue sections of 22 MEC and 6 ACC tumors of the major salivary glands were evaluated immunohistochemically for expression of erbB-2, erbB-3, EGRF, and TGF-alpha. A differential immunostaining score, reflecting the difference in immunostaining between carcinoma and uninvolved salivary gland tissue, was calculated for cytoplasmic and membranous staining. RESULTS: Positive immunostaining for all biomarkers was observed in the cytoplasm and membrane of both tumors. However, expression was higher in MEC than in ACC tumors and was statistically significant for cytoplasmic EGFR (P =.009), TGF-alpha (P =.041), and membranous EGFR (P =.004). A significantly higher percentage of MEC cells also demonstrated positive immunostaining for cytoplasmic erbB-3 (P =.022), EGFR (P =.005), membranous erbB-3 (P =.022), and EGFR (P =.013). The differential immunostaining score was significantly higher for MEC compared with uninvolved alveolar tissue and the membranes of uninvolved ductal tissue. There were no statistically positive differential immunostaining scores for ACC. CONCLUSIONS: There is a clear difference in the molecular phenotypes of MEC and ACC. The lack of statistically significant expression in ACC, when compared with similar uninvolved salivary gland tissue, suggests minimal involvement for these molecular structures in the pathogenesis of ACC. Conversely, erbB-2, erbB-3, EGFR, and TGF-alpha may have a role in the development and progression of MEC. These results have therapeutic implications for MEC of the major salivary glands.

Carcinoma, Adenoid Cystic↗

PubMed2001

Molecular characterization of colorectal neoplasia in translational research.

OBJECTIVE: To present recent advances in the use of molecular markers in diagnosis, in prognosis, in early detection, in novel therapies, and in understanding the molecular pathogenesis of colorectal neoplasia. DATA AND LITERATURE SOURCES: A review of studies of molecular markers in colorectal neoplasia, published in English and available on MEDLINE and BioMednet, indicates that molecular markers are being increasingly studied to predict clinical outcomes in patients with colorectal adenocarcinoma (CRC). We have used this resource, together with our published and unpublished observations at the University of Alabama at Birmingham, to provide an overview of translational research related to molecular markers in colorectal neoplasia. CONCLUSIONS: Currently, the prognosis of patients with CRC is predicted primarily on the basis of clinicopathologic staging; however, pathologists and oncology surgeons have recently begun to investigate the use of molecular markers to diagnose and/or understand the progression of CRC. In recent years, much has been learned about the molecular events responsible for the development of CRC. Also, several studies have reported the implication of some molecular markers in metastasis and tumor aggression and their usefulness in predicting clinical outcome. In this article, we discuss the use of specific molecular markers, including tumor-associated glycoprotein 72 (TAG-72), carcinoembryonic antigen (CEA), and oncofetal tumor antigens (Lewis X and Y) in diagnosis and as targets for novel therapies, as well as the phenotypic expression of bcl-2, mucin antigens (MUC1 and MUC2), and nuclear accumulation of p53 in predicting the clinical outcome of patients with CRC. We also review the ways in which molecular markers may aid the early detection of colorectal neoplasia and promote our understanding of the earliest changes in colorectal neoplasia.

Adenocarcinoma↗

PubMed2001

Fatty acid synthase: an early molecular marker of progression of prostatic adenocarcinoma to androgen independence.

PURPOSE: Changes in fatty acid synthase levels were investigated in the CWR22 xenograft model of prostatic adenocarcinoma after castration and during progression to androgen independence. MATERIALS AND METHODS: Male nude mice with CWR22 tumors were castrated and sacrificed 3, 7, 21, 28 or 42 days after castration. Some mice received testosterone replenishment 21 days after castration and were sacrificed 7 days later. In addition, other castrates were maintained for 7 to 10 months to allow tumors to relapse to androgen independence. Fatty acid synthase was measured by immunohistochemical study and Western blot analysis. RESULTS: Fatty acid synthase decreased rapidly after castration and after 28 to 42 days it was 5% to 10% of the level in tumors of intact controls. Temporal changes in fatty acid synthase after castration were associated with decreased proliferative potential and increased levels of the cyclin dependent kinase inhibitor p27Kip-1. Testosterone treatment of castrates at 21 to 28 days after castration increased fatty acid synthase expression to the level in tumors of intact controls. Tumors of long-term castrates with post-castration androgen independent growth had increased fatty acid synthase, as did small focal areas of androgen independent proliferation in tumors that had not increased in size by 7 to 10 months. In relapsed CWR22 tumors and in focal areas of androgen independent proliferation in nonrelapsed CWR22 tumors increased fatty acid synthase was associated spatially with increased proliferation and decreased p27Kip-1. CONCLUSIONS: Fatty acid synthase in CWR22 tumors depends initially on testosterone and it is associated with androgen mediated proliferation. Furthermore, increased fatty acid synthase levels associated with androgen independent proliferation may represent an early event in the development of the androgen independent phenotype.

Adenocarcinoma↗

PubMed2001

Altered subcellular localization of suppressin, a novel inhibitor of cell-cycle entry, is an independent prognostic factor in colorectal adenocarcinomas.

PURPOSE: Suppressin (SPN), a novel inhibitor of the entry into the cell cycle, has properties of a tumor suppressor gene; however, its role in the development and progression of a human malignancy is not studied. Therefore, we evaluated the status of spn and its prognostic value in human colorectal adenocarcinoma (CRC). EXPERIMENTAL DESIGN: Inhibition of cell proliferation by exogenous/extracellular SPN was assessed by [(3)H]thymidine incorporation. The genetic status of spn in two colon cancer cell lines (LS180 and WiDr) and in a human CRC was determined using direct cDNA sequencing techniques. Phenotypic expression of SPN was evaluated in 105 CRC archival tissues using immunohistochemical methods. Univariate Kaplan-Meier and multivariate Cox proportional hazards models were used to determine the prognostic significance of SPN expression. RESULTS: Exogenous SPN inhibited the proliferation of the LS180 cell line, which also has a mutation in one allele of the spn gene. The spn gene was also mutated in the primary CRC. Expression of SPN was primarily cytoplasmic in nonmucinous CRCs and nuclear in mucinous CRCs. However, the evaluation of 85 nonmucinous CRCs demonstrated that nuclear localization of SPN, nuclear accumulation of p53, and nodal status were independent prognostic indicators with hazard ratios of 2.34, 2.33, and 3.04, respectively. Nuclear localization of SPN plus nuclear accumulation of p53 formed a stronger prognostic indicator (hazard ratios = 5.45) than local nodal status. CONCLUSIONS: This is the first report of genetic alterations in the spn gene in a human malignancy and suggests that genetic alterations in spn and the resulting immunohistochemical phenotypes based on SPN subcellular localization in CRCs may be useful in determining prognosis of patients with subtypes of CRC.

Adenocarcinoma↗

PubMed2000

Bcl-2 expression is associated with improved prognosis in patients with distal colorectal adenocarcinomas.

Several recent studies have suggested that the anatomic location of the tumor and ethnicity of the patient should be considered in the evaluation of prognostic markers of colorectal neoplasia. The phenotypic expression of Bcl-2 has been reported to be a useful prognostic marker in colorectal adenocarcinoma (CRC). However, its prognostic importance in CRCs based on their anatomic location and on the ethnicity of the patients has not been reported. Therefore, we evaluated Bcl-2 expression by immunohistochemistry in CRCs collected from 107 African-American and 149 Caucasian patients from a southern U.S. population. In univariate Kaplan-Meier survival analyses, Bcl-2 expression was associated with better overall survival of both African-American (log-rank, p = 0.040) and Caucasian (log-rank, p = 0.032) patients with distal but not with proximal CRCs. In multivariate Cox regression analyses, when the pathologic features of tumors were not included, the expression of Bcl-2 was associated with better survival in either ethnic patient populations with distal CRCs after adjusting for other confounding variables and p53(nac) status; however, it was not significant in either race when tumor stage was included in multivariate analyses. Thus, these studies suggest that the expression of Bcl-2 in CRCs is a valuable indicator of good prognosis in either race when CRCs are located in the distal colorectum. Also, these studies suggest that the expression of Bcl-2 is useful in determining prognosis before pathologic-clinical staging and it can aid in selection of treatment after evaluation of diagnostic biopsy specimens of patients with distal colorectal adenocarcinomas.

Adenocarcinoma↗

PubMed2000

Neutralization and enhancement of HIV-1 infection by sera from HIV-1 infected individuals who progress to disease at different rates.

We examined the neutralizing/enhancing activity in sera collected at an early and a later time point postinfection from 13 HIV-positive nonprogressors, 13 moderate progressors, and 13 rapid progressors to determine the relationship between neutralizing/enhancing activity and disease progression. Early sera from each group reduced virus replication at low dilutions (10(-1) to 10(-2)) when compared with negative sera. The reduction was statistically significant for moderate and rapid progressors at 10(-1) dilution (P = 0.02 and P = 0.02 respectively) but not for nonprogressors (P = 0.16). Late sera from nonprogressors and moderate progressors reduced virus replication at low dilution but late sera from rapid progressors lost neutralizing activity. These data suggest that an association exists between neutralizing activity in sera and nonprogression or slower progression to disease and that loss of neutralizing activity is associated with disease progression. At higher dilutions (10(-3) to 10(-6)), both early and late sera from each group increased virus replication over negative sera. The levels and frequency of enhancement were higher for sera from a subgroup of nonprogressors than a subgroup of rapid progressors who exhibited enhancement. This suggests that enhancement is not associated with disease progression. The neutralizing/enhancing activity observed in sera of these three groups of subjects suggest that enhancement levels may reflect the overall level of antibody response to HIV. The replication patterns observed for early and late sera from individuals in the different groups reflect changes in antibody activity that appear to be associated with protection or disease progression.

Acquired Immunodeficiency Syndrome↗

PubMed2000

Outcome for children with supratentorial primitive neuroectodermal tumors treated with surgery, radiation, and chemotherapy.

BACKGROUND: The outcome of a child with a primitive neuroectodermal tumors arising supratentorially (SPNET) is not well characterized and may differ from the outcome of a patient with a histologically similar cerebellar tumor (medulloblastoma [MB]). Recently, 5-year progression free survival rates as high as 80% have been reported for children with MB treated with craniospinal radiation (CRT) and chemotherapy including cisplatin, lomustine (CCNU), and vincristine (VCR). METHODS: The authors reviewed the outcome of 22 consecutive patients age 3 years and older (mean age, 10 years; range, 3-18 years) with SPNET who were treated at the study institutions between 1981 and 1996. Tumor location included was 13 pineal, 6 cortical, and 3 thalamic or suprasellar. Five patients had disease dissemination at diagnosis. All patients underwent surgery and staging, followed by CRT and chemotherapy with cisplatin, CCNU, and VCR. RESULTS: Of the 22 patients, 13 had developed disease progression and 10 had died at the time of last follow-up. Overall progression free survival (PFS) was 47% +/- 11% at 3 years and 37% +/- 11% at 5 years. There was a significant difference in PFS between patients with localized disease versus those with disseminated disease (P = 0.04). There was no statistical association between tumor location and survival. Although not significant (P = 0.21), there was a trend toward better survival of those patients with complete or near-complete resection compared with those with partial resection or biopsy. CONCLUSIONS: The results of the current study demonstrate that the outcome for children with SPNET treated with radiation and chemotherapy appears worse than for children with MB treated with identical therapy. This suggests that there may be biologic differences between supratentorial and infratentorial primitive neuroectodermal tumors, thus requiring refinements in treatment.

Adolescent↗

PubMed2000

Breast-feeding and weight change in newborns in Jamaica.

This study was conducted to examine weight change of exclusively breast-fed infants during the first week and through the first 24 days of life, and to evaluate the effect of breast-feeding factors and maternal characteristics on early weight change in the infants. The weights of 21 infants were recorded on day 1 (day of birth), and on days 3, 7, 10, 17, and 24, and the data analysed to evaluate weight change over the period. Multiple regression analysis was used to assess whether birth weight as well as maternal and breast-feeding factors were significant predictors of weight on day 24. Nineteen of the 21 infants gained weight between days 1 and 3, and 20 infants gained weight between days 3 and 7. All infants gained weight over the 24-day period and their weights at day 7 and day 24 were significantly different (P < 0.05 and P < 0.01, respectively) from their birth weights. Multiple linear regression analysis showed that significant (P < 0.01) predictors of weight gain by day 24 included birth weight, mother's educational level, whether the baby cried before feeding, and length of feeding time periods. This is the first study of weight change in the early days and weeks of life of exclusively breast-fed newborn infants in Jamaica. The infants showed significant weight gain during the study period and weight gain was affected by certain maternal and breast-feeding factors.

Adult↗

PubMed2000

Do adaptive changes in metabolic rate favor weight regain in weight-reduced individuals? An examination of the set-point theory.

BACKGROUND: Obese persons generally regain lost weight, suggesting that adaptive metabolic changes favor return to a preset weight. OBJECTIVE: Our objective was to determine whether adaptive changes in resting metabolic rate (RMR) and thyroid hormones occur in weight-reduced persons, predisposing them to long-term weight gain. DESIGN: Twenty-four overweight, postmenopausal women were studied at a clinical research center in four 10-d study phases: the overweight state (phase 1, energy balance; phase 2, 3350 kJ/d) and after reduction to a normal-weight state (phase 3, 3350 kJ/d; phase 4, energy balance). Weight-reduced women were matched with 24 never-overweight control subjects. After each study phase, assessments included RMR (by indirect calorimetry), body composition (by hydrostatic weighing), serum triiodothyronine (T(3)), and reverse T(3) (rT(3)). Body weight was measured 4 y later, without intervention. RESULTS: Body composition-adjusted RMR and T(3):rT(3) fell during acute (phase 2) and chronic (phase 3) energy restriction (P: < 0.01), but returned to baseline in the normal-weight, energy-balanced state (phase 4; mean weight loss: 12.9 +/- 2.0 kg). RMR among weight-reduced women (4771 +/- 414 kJ/d) was not significantly different from that in control subjects (4955 +/- 414 kJ/d; P: = 0.14), and lower RMR did not predict greater 4-y weight regain (r = 0.27, NS). CONCLUSIONS: Energy restriction produces a transient hypothyroid-hypometabolic state that normalizes on return to energy-balanced conditions. Failure to establish energy balance after weight loss gives the misleading impression that weight-reduced persons are energy conservative and predisposed to weight regain. Our findings do not provide evidence in support of adaptive metabolic changes as an explanation for the tendency of weight-reduced persons to regain weight.

Aged↗

PubMed2000

Racial differences in the prognostic usefulness of MUC1 and MUC2 in colorectal adenocarcinomas.

There is a need for new prognostic parameters that could add insights into the aggressiveness of tumors. Because the expression of two well-characterized mucin antigens, MUC1 and MUC2, in colorectal adenocarcinomas (CRCs) has been correlated with the aggressiveness of CRCs, we evaluated the prognostic value of the expression of MUC1 and MUC2 in CRCs collected from African-American and Caucasian patients. Expression of MUC1 and MUC2 was evaluated by immunohistochemistry in 166 archival CRC specimens collected from 58 African-American and 108 Caucasian patients that had been analyzed previously for nuclear accumulation of p53 (p53nac). Univariate Kaplan-Meier and multivariate Cox proportional hazards models were used to determine the prognostic significance of expression of MUC1 and MUC2 in these CRCs. MUC1 expression was more frequent in advanced stage CRCs, whereas MUC2 expression was higher in the mucinous type of CRCs. Although similar proportions of CRCs from African-Americans and Caucasians expressed MUC1 and MUC2, the MUC1 expression was found to be an indicator of high risk of death from CRC in Caucasians (hazard ratio, 2.03; P = 0.038) but not in African-Americans. Furthermore, Caucasians with CRCs exhibiting concomitant expression of MUC1 and p53nac demonstrated the lowest probability of overall survival (log rank test, P = 0.004). No prognostic value was found for MUC2 alone or in combination with p53nac in either group of patients. Expression of MUC1 in CRCs is a valuable indicator of poor prognosis in Caucasian patients. Additionally, combined evaluation of MUC1 and p53nac increases the ability to identify Caucasian patients with aggressive subtypes of CRC and may be useful in selecting or in developing novel therapeutic regimes.

Adenocarcinoma↗

PubMed1999

A mixed model for factors predictive of pain in AIDS patients with herpes zoster.

A unifying model of herpes zoster pain presents considerable analytical challenges due to the requirement for prospective data collection and the varying rates of pain resolution reported by individual patients. Demographic, clinical, and quality-of-life measures were collected on 166 human immunodeficiency virus (HIV)-infected patients enrolled in a randomized, controlled trial of antiviral therapy of herpes zoster comparing acyclovir with sorivudine. A "mixed model" was used to assess factors predictive of pain severity, activity impairment, and sleep interruption. The average rate of change in acute pain was -0.04 unit pain per day for the first month. Chronic pain decreased -0.12 per month for months 1-12. Acute pain severity was positively correlated with number of new skin vesicles, analgesic use, and baseline pain, and negatively related to percentage of lesion healing and crusting. Postherpetic neuralgia was correlated with baseline pain, pain at 1 month, and duration of lesions. Treatment group, gender, race, and CD4 count were not related to change in pain severity. These analyses verify the significance of baseline pain as a significant predictor of pain resolution and average pain severity as a predictor of return to normal daily activities and sleep. The severity of acute pain at presentation and at 1 month are significant predictors of chronic pain.

Acquired Immunodeficiency Syndrome↗

PubMed1999

Bayesian monitoring of phase II trials in cancer chemoprevention.

Early randomized Phase II cancer chemoprevention trials which assess short-term biological activity are critical to the decision process to advance to late Phase II/Phase III trials. We have adapted published Bayesian interim analysis methods (Spiegelhalter et al., J. R. Statist. Soc A, 1994; 157: 357-416) which give greater flexibility and simplicity of inference to the monitoring of randomized controlled Phase II trials using intermediate endpoints. The Bayesian stopping rule is designed to stop the trial more quickly when the evidence suggests ineffectiveness rather than when it suggests biological activity, thus allowing resources to be concentrated on those agents that show the most promise in this early stage of testing. We investigate frequentist performance characteristics of the proposed method through simulation of randomized placebo controlled trials with a growth factor intermediate end-point using mean and variance values derived from the literature. Simulation results show expected error rates and trial size similar to other commonly used group sequential methods for this setting. These results suggest that the Bayesian approach to interim analysis is well suited for monitoring small randomized controlled Phase II chemoprevention trials for early detection of either inactive or promising agents.

Antineoplastic Agents↗

PubMed1999

Herpes zoster: risk categories for persistent pain.

Acute neuritis and persistent pain are the most significant clinical manifestations of herpes zoster and are end points for clinical trials therapy. In an acyclovir and prednisone study, patients were categorized according to pain severity and number of lesions at presentation. Risk categories were defined according to the magnitude of risk ratios (RRs) and a comparison of Kaplan-Meier survival estimates. For acute neuritis and zoster-associated pain, RRs defined rate of resolution. Patients who presented with severe or incapacitating pain and a large number of lesions were less likely to achieve resolution of both acute neuritis and zoster-associated pain (RR, 18.0; 95% confidence interval [CI], 6. 6-48.6, and RR, 5.3; 95% CI, 4.2-17.2, respectively). These analyses identify the subgroups of patients for whom aggressive interventions are most strongly indicated.

Activities of Daily Living↗