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Biomedical subjects

B H Pollock

Publications and source records attributed to B H Pollock.

At least 37 records · Page 2Linked to original sources
PubMed2000

Racial differences in the survival of childhood B-precursor acute lymphoblastic leukemia: a Pediatric Oncology Group Study.

PURPOSE: We conducted a historic cohort study to test the hypothesis that, after adjustment for biologic factors, African-American (AA) children and Spanish surname (SS) children with newly diagnosed B-precursor acute lymphoblastic leukemia had lower survival than did comparable white children. PATIENTS AND METHODS: From 1981 to 1994, 4,061 white, 518 AA, and 507 SS children aged 1 to 20 years were treated on three successive Pediatric Oncology Group multicenter randomized clinical trials. RESULTS: AA and SS patients were more likely to have adverse prognostic features at diagnosis and lower survival than were white patients. The 5-year cumulative survival rates were (probability +/- SE) 81.9% +/- 0.6%, 68.6% +/- 2.1%, and 74.9% +/- 2.0% for white, AA, and SS children, respectively. Adjusting for age, leukocyte count, sex, era of treatment, and leukemia blast cell ploidy, we found that AA children had a 42% excess mortality rate compared with white children (proportional hazards ratio [PHR] = 1.42; 95% confidence interval [CI], 1.12 to 1. 80), and SS children had a 33% excess mortality rate compared with white children (PHR = 1.33; 95% CI, 1.19 to 1.49). CONCLUSION: Clinical presentation, tumor biology, and deviations from prescribed therapy did not explain the differences in survival and event-free survival that we observed, although differences seem to be diminishing over time with improvements in therapy. The disparity in outcome for AA and SS children is most likely related to variations in chemotherapeutic response to therapy and not to compliance. Further improvements in outcome may require individualized dosing based on specific pharmacogenetic profiles, especially for AA and SS children.

Adolescent↗
PubMed2000

Characterization and outcome of "hard to mobilize"' lymphoma patients undergoing autologous stem cell transplantation.

A "hard to mobilize" patient was defined as one in whom >or= 1x10(6) CD 34+ cells/kg cannot be obtained after two consecutive large volume aphereses. Forty-four consecutive Hodgkin's and non-Hodgkin's lymphoma patients who underwent autologous peripheral blood stem cell (PBSC) transplant treatment between June 1996 and June 1998 were included in this study. Twenty-one patients (48%) met the definition of "hard to mobilize" (Group I). All the rest of the patients (n=23) were the good mobilizers (Group II). The initial mobilization protocol for most patients was 10 microg/kg of G-CSF alone for both groups. For Group I, 7/21 (33%) patients were unable to achieve a minimal dose of >or= 1x10(6) CD34+ cells/kg even after a second mobilization attempt and/or bone marrow (BM) harvest (n=5). Overall, 11/21 (52%) required an additional mobilization and/or BM harvest. Only 3/21 (14%) patients were able to meet the target cell dose of >or= 2.5x10(6) CD34+ cells/kg (median of 4 apheresis). In contrast, 87% of Group II achieved the target dose with a median of 2 aphereses. Predictors of poor mobilization were greater than two prior treatment regimens (p=0.038) and the WBC count (<25,000/microL) on the first day of apheresis (p=0.053). Nineteen patients in Group I and all Group II completed treatment with a median time to engraftment of ANC>500/microl of 12 and 11 days, and platelet >20x10(3)/microl of 31 and 13 days, respectively. Outcome analysis revealed that 6/19 patients in Group I died of relapse within one year from transplant compared with only 2/23 of Group II who died of relapse (p=0.005, log rank test). There were no treatment related deaths in either group. Independent predictive features for "hard to mobilize" patients are a lack of significant increase in WBC count on the first day of apheresis and the number of prior treatment regimens. Poor mobilization appears to predict a worse outcome after autografting for lymphoma patients.

Actuarial Analysis↗
PubMed2000

Parental smoking and alcohol consumption and risk of neuroblastoma.

Previous studies and animal evidence have suggested a relationship between parental tobacco or alcohol use and the risk of some childhood cancers, including neuroblastoma. A case-control study was conducted to investigate the relationship between parental tobacco smoking, alcohol consumption, and risk of neuroblastoma. Cases were children diagnosed with neuroblastoma over the period 1992-1994 at Children's Cancer Group and Pediatric Oncology Group institutions throughout the United States and Canada. One matched control was selected using random-digit dialing. Information on parental smoking and drinking history was obtained from 504 case and 504 control parents by telephone interview. Overall, there was no consistent pattern of association with parental smoking and alcohol consumption. For example, both maternal smoking and drinking during the period from 1 month before pregnancy through breastfeeding had adjusted odds ratios (ORs) of 1.1 [95% confidence interval (CI), 0.8-1.4]. There was no association with paternal smoking (OR, 1.2; 95% CI, 0.8-1.6) or paternal drinking 1 month before conception (OR, 1.0; 95% CI, 0.7-1.4). There was no consistent increase in risk by the amount of smoking or drinking during any time period relative to pregnancy. There was no suggestion of an increased risk when only one parent smoked. Smoking or drinking among both parents did not jointly increase the risk of neuroblastoma in their offspring. The child's age at diagnosis, stage, or MYCN oncogene amplification status did not materially alter the OR estimates. It is concluded that the results from this study do not indicate any evidence for a relationship between neuroblastoma and parental tobacco or alcohol use.

Adolescent↗
PubMed1999

Hormone and fertility drug use and the risk of neuroblastoma: a report from the Children's Cancer Group and the Pediatric Oncology Group.

Previous epidemiologic studies have suggested an association between maternal sex hormone use during pregnancy, including infertility medication, and an increased risk of neuroblastoma in the offspring. The authors conducted a case-control interview study from 1992 to 1996 that included 504 children less than 19 years of age whose newly diagnosed neuroblastoma was identified by two national collaborative clinical trials groups in the United States and Canada, the Children's Cancer Group and the Pediatric Oncology Group. Controls, matched to cases on age, were identified by random digit dialing. No association was found for use of oral contraceptives before or during pregnancy (first trimester odds ratio (OR) = 1.0, 95% confidence interval (CI): 0.5, 2.1). The odds ratio was slightly elevated for history of infertility (OR = 1.4, 95% CI: 0.9, 2.1) and ever use of any infertility medication (OR = 1.2, 95% CI: 0.7, 2.2). Specifically, ever use of clomiphene was associated with a 1.6-fold increased risk (95% CI: 0.8, 3.0) but not periconceptionally or during the index pregnancy. A suggestive pattern was found for gender of the offspring, with an increased risk for males but not for females after exposure to oral contraceptives or clomiphene. This study did not find consistent and large increased risks for maternal use of hormones, but the suggestion of an association for male offspring requires further consideration.

Adult↗
PubMed1999

Human herpesvirus-8 (HHV-8) associated with small non-cleaved cell lymphoma in a child with AIDS.

The association of human herpesvirus-8 (HHV-8) with a small non-cleaved cell lymphoma is described in a child with the acquired immunodeficiency syndrome (AIDS) who developed a malignant pleural effusion and radiologic evidence of multiple solid tumors. HHV-8 DNA and Epstein-Barr virus DNA were identified in pleural fluid cells by polymerase chain reaction (PCR) amplification. The serum antibody titer against lytic HHV-8 proteins was 1:640; antibodies to latent HHV-8 proteins were not detected. Cytogenetic analysis of malignant cells revealed three abnormal karyotypes sharing the common finding of a t(8;14) translocation. Rearrangement of c-myc was demonstrated by PCR analysis. Oligoclonal JH immunoglobulin bands were found. Insufficient pleural fluid cells were available to permit localization of HHV-8 to malignant cells by in situ hybridization. This malignancy contrasts with HHV-8-associated lymphomas reported in adult patients with AIDS with respect to cell morphology, c-myc translocation, and oligoclonal immunoglobulin gene rearrangement. HHV-8 is associated with a wider spectrum of malignancies than recognized previously.

Adult↗
PubMed1999

Neuroblastoma and parental occupation.

OBJECTIVES: We evaluated parental occupation and the risk of neuroblastoma using data from a large case-control study conducted by the Children's Cancer Group and the Pediatric Oncology Group. METHODS: We compared the distribution of 73 paternal and 57 maternal occupational groups among 504 newly diagnosed cases of neuroblastoma and individually matched controls obtained by telephone random digit dialing in the United States and Canada. RESULTS: An increased risk of neuroblastoma was found for fathers employed as broadcast, telephone and dispatch operators (odds ratio [OR] = 6.1; 95% confidence interval [CI] = 0.7-50.9), electrical power installers and power plant operators (OR = 2.7; CI = 0.9-8.1), landscapers and groundskeepers (OR = 2.3; CI = 1.0-5.2), and painters (OR = 2.1; CI = 0.9-4.8). Elevated odds ratios were found for mothers employed as farmers and farm workers (OR = 2.2; CI = 0.6-8.8), florists and garden store workers (OR = 2.4; CI = 0.6-9.9), hairdressers and barbers (OR = 2.8; CI = 1.2-6.3), electric power installers and power plant operators, and sailors, fishers, and railroad workers. No increase in risk was found for other paternal occupations previously associated, including electricians, electrical equipment assemblers and repairers (OR = 1.1; CI = 0.6-2.0), or welders (OR = 0.5; CI = 0.1-1.6). CONCLUSION: The study reinforced some prior evidence of increased risks in electrical, farming and gardening, and painting occupations, but failed to confirm other previously reported associations. Further analyses of exposure to electromagnetic fields, metals, solvents, and pesticides are currently under way.

Adolescent↗
PubMed1999

Seasonal variations in the diagnosis of childhood cancer in the United States.

Seasonal trends in month of diagnosis have been reported for childhood acute lymphoblastic leukaemia (ALL) and non-Hodgkin's lymphoma (NHL). This seasonal variation has been suggested to represent an underlying viral aetiology for these malignancies. Some studies have shown the highest frequency of diagnoses in the summer months, although this has been inconsistent. Data from the Children's Cancer Group and the Pediatric Oncology Group were analysed for seasonal incidence patterns. A total of 20,949 incident cancer cases diagnosed in the USA from 1 January 1989 through 31 December 1991 were available for analyses. Diagnosis-specific malignancies available for evaluation included ALL, acute myeloid leukaemia (AML), Hodgkin's disease, NHL, rhabdomyosarcoma, neuroblastoma, retinoblastoma, osteosarcoma, Wilms' tumour, retinoblastoma, Ewings' sarcoma, central nervous system (CNS) tumours and hepatoblastoma. Overall, there was no statistically significant seasonal variation in the month of diagnosis for all childhood cancers combined. For diagnosis-specific malignancies, there was a statistically significant seasonal variation for ALL (P = 0.01; peak in summer), rhabdomyosarcoma (P = 0.03; spring/summer) and hepatoblastoma (P = 0.01; summer); there was no seasonal variation in the diagnosis of NHL. When cases were restricted to latitudes greater than 40 degrees ('north'), seasonal patterns were apparent only for ALL and hepatoblastoma. Notably, 33% of hepatoblastoma cases were diagnosed in the summer months. In contrast, for latitudes less than 40 degrees ('south'), only CNS tumours demonstrated a seasonal pattern (P = 0.002; winter). Although these data provide modest support for a summer peak in the diagnosis of childhood ALL, any underlying biological mechanisms that account for these seasonal patterns are likely complex and in need of more definitive studies.

Adolescent↗
PubMed1999

Altered IGF-I and IGFBPs in senescent male and female rats.

The effects of senescence on muscle characteristics and the insulin-like growth factor I (IGF-I) pathway were assessed in male and female BN/F344 rats. The mass and total ATPase activity of gastrocnemius and plantaris muscles were reduced with age and to a greater extent in males than in females. The mass and total ATPase activity of soleus muscle were not significantly altered with age. Circulating IGF-I was also significantly reduced with age, 60% in females and 21% in males. Circulating IGF-binding protein 3 (IGFBP-3) was reduced with age. In liver and gastrocnemius muscle, mRNAs for IGF-1, IGFBP-2, and IGFBP-3 were analyzed in young and aged males of two strains, BN/F344 and Sprague-Dawley. In BN/F344 rats, liver mRNAs were unchanged with age. Also in BN/F344 rats, muscle mRNAs for IGFBP-2, and IGFBP-3 displayed nonsignificant trends toward increase with age. In aged Sprague-Dawley males, liver mRNA for IGF-I was increased 15% and muscle mRNA for IGFBP-2 was increased 110%. Thus, different age-related changes in the growth hormone (GH)/IGF pathway occur in males and females between the sexes and strains. These changes may play a role in the muscle atrophy associated with senescence.

Adenosine Triphosphatases↗
PubMed1999

Nonimmune hydrops fetalis: fetal and neonatal outcome during 1983-1992.

Prognostic factors for survival of 62 fetuses and neonates with nonimmune hydrops fetalis (NIHF) were studied retrospectively. Twenty-eight infants survived >/=28 days which is 45% for all fetuses and newborns diagnosed with NIHF and 61% for liveborns with unresolved NIHF. Univariate analysis identified that mortality was associated with the presence of >/=2 serous cavity effusions and a need for chest compressions at birth. Multivariate logistic regression analysis confirmed that the presence of >/=2 serous cavity effusions was significantly associated with mortality from NIHF <28 days after birth [OR = 48.2 (CI 3.6, 662.9) (p < 0.004)]. We conclude that, compared to published cases from the 1970s and early 1980s, survival of liveborns with NIHF seems improved. The decrease in stillbirths is more notable. The severity of hydrops at birth is the key determinant for survival.

Female↗
PubMed1999

Improved survival of children with isolated CNS relapse of acute lymphoblastic leukemia: a pediatric oncology group study .

PURPOSE: Isolated meningeal relapse in children with acute lymphoblastic leukemia (ALL) usually has been followed by bone marrow relapse and limited survival. The purpose of this study was to prevent marrow relapse by administering intensive therapy before delayed craniospinal radiation. PATIENTS AND METHODS: Eighty-three patients with ALL in first bone marrow remission with an isolated CNS relapse were treated with systemic chemotherapy known to enter into the CSF and intrathecal chemotherapy for 6 months. Craniospinal irradiation (24 Gy cranial/15 Gy spinal) was then administered, followed by 1.5 years of maintenance chemotherapy. RESULTS: All 83 patients achieved a second remission. The 4-year event-free survival (EFS) rate was 71.1% +/- 5.3%. There was a fourfold increased risk of relapse for children whose initial remission was less than 18 months. The 4-year EFS rate for patients with a first complete remission >/= 18 months was 83.3% +/- 5.3%, and for those with a first complete remission less than 18 months, it was 46.2% +/- 10.2% (P =.0002.) There was a low incidence of neurologic toxicity and an unexpectedly high rate of allergic reactions to L-asparaginase. Five patients developed secondary malignancies: two with acute nonlymphoblastic leukemia during therapy, one with myelodysplasia after therapy, and two with brain tumors 1.5 to 2 years after cessation of therapy. CONCLUSION: For children with ALL and an isolated CNS relapse, treatment that delays definitive craniospinal irradiation by 6 months to allow for more intensive systemic and intrathecal chemotherapy results in better EFS than has been previously reported. Using this approach, the long-term prognosis for children with first complete remission >/= 18 months is comparable to that at the time of original diagnosis of ALL.

Adolescent↗
PubMed1998

Long-term glycemic control influences the onset of limited joint mobility in type 1 diabetes.

BACKGROUND: Limited joint mobility (LJM) in childhood insulin-dependent (type 1) diabetes is associated with a substantially increased risk of microvascular complications. Cross-sectional studies have not demonstrated a relationship between LJM and metabolic control. This study was designed to determine whether glycemic control, as measured by glycohemoglobin (hgbA1C) levels from the onset of diabetes, is associated with the occurrence of LJM. METHOD: Probands (n = 18) had hgbA1C values and recorded observation of joint function from soon after onset of their diabetes. Controls (n = 40) were matched to probands for gender and age at diagnosis and had follow-up beyond the age at which the proband was found to have LJM. RESULTS: The odds ratio for occurrence of LJM for the mean hgbA1C from diabetes onset was 1.46, 95% confidence limits 1.07 to 2.00. Thus, for every unit increase in average hgbA1C, there was approximately a 46% increase in the risk of LJM. When hgbA1C was dichotomized, the OR for hgbA1C of more than 8% was 2.55, and the OR was 4.54 if the hgbA1C was greater than 12%. Age at diagnosis and duration of diabetes were not independent prognostic factors for LJM. CONCLUSION: Glycemic control from onset of diabetes is strongly associated with occurrence of LJM.

Case-Control Studies↗
PubMed1998

The role of intravenous immunoglobulin for the prevention and treatment of neonatal sepsis.

The use of intravenous immunoglobulin (IVIG) for the prevention and treatment of sepsis in neonates is appealing because of the relative immunodeficiency of the neonate and the desire to improve the relatively poor outcome even with optimal antimicrobial treatment. The effectiveness of IVIG for these uses has been studied in numerous prospective as well as retrospective small and large trials that have had discordant conclusions. Meta-analysis demonstrates the marginal but significant benefit of prophylactic IVIG administered shortly after birth in preventing early onset sepsis in premature low birth weight newborns (P = .0193, two-sided). The expense of prophylactic use of IVIG administration for the relatively large premature newborn population given the minimal benefit as demonstrated by original studies and by meta-analysis is not justified. In contrast, meta-analysis of studies of IVIG for the treatment of neonates with sepsis shows a significant and unequivocal sixfold decrease in the mortality rate (P = .007, two-sided) when IVIG is administered in addition to standard therapies. The additional benefit of decreasing the risk for acute mortality indicates that the inclusion of IVIG should be considered a part of the routine therapy of neonatal sepsis.

Cross Infection↗
PubMed1997

The age peak in childhood acute lymphoblastic leukemia: exploring the potential relationship with socioeconomic status.

BACKGROUND: White children have a much higher incidence rate of acute lymphoblastic leukemia (ALL) than do African American children. This discrepancy, coupled with the geographic and temporal variations in the incidence of childhood ALL, have led to speculation that factors associated with socioeconomic status (SES) may play an important role in its etiology. Because most of the variation is accounted for by the occurrence of a peak in incidence between the ages of 2 and 5 years, the purpose of this study was to compare the SES of children diagnosed with ALL between the peak ages of 2-5 years with those children diagnosed at other ages (birth-1 year and 6-14 years). METHODS: Patients included 4210 children who were diagnosed with ALL between January 1, 1989 and December 31, 1991 by a member institution of the Children's Cancer Group or the Pediatric Oncology Group. Of these children, 3614 were white and 596 were African American. The SES of a case was defined as the SES of the child's zip code of residence at the time of diagnosis. Five sociodemographic variable categories for each zip code were obtained from the 1990 U.S. Census including per capita income, number of housing units by household income, number of housing units by level of urbanization, number of persons older than 25 years by educational attainment, and number of persons by occupation. Mean values were compared for white children versus African American children, and peak ages (2-5 years) versus nonpeak ages (birth-1 year and 6-14 years) for both whites and African Americans. In addition, Wilcoxon's rank sum tests were performed. RESULTS: There were statistically significant differences between the means in each of the socioeconomic categories when African Americans were compared with whites. However, within race, the means of the SES variables for white children diagnosed during the peak ages (2-5 years) were not significantly different from children diagnosed at other ages (birth-1 year and 6-14 years). Similarly, all but one of the comparisons for African American children yielded nonstatistically significant results. Similar results were obtained from the Wilcoxon's rank sum tests. CONCLUSIONS: The results of this analysis suggest that age differences in childhood ALL incidence may not be solely accounted for by SES differences.

Adolescent↗
PubMed1997

Shortened survival after relapse in T-cell acute lymphoblastic leukemia patients with p16/p15 deletions.

p16 Alterations were detected in > 60% of 103 primary T-ALL samples. In paired diagnosis-relapse patient samples, 80% of the relapse samples with p16 deletion were deleted at diagnosis. When p16 was homozygously deleted, p15 gene alterations were found in 72% of the diagnosis T-ALL patient samples, increasing significantly to 100% at relapse. Alterations of p18 were not detected. No clinical significance of p15/p16 gene deletion in diagnosis T-ALL was found with respect to white blood cell (WBC) count, incidence of mediastinal mass, rate of relapse, duration of first remission or event-free survival. In relapse T-ALL, however, patients with p16 deletion experienced a significantly shorter duration of post-relapse survival, demonstrating that p16 deletion is clinically significant in T-ALL.

Carrier Proteins↗
PubMed1997

National cancer clinical trials: children have equal access; adolescents do not.

PURPOSE: To determine whether adolescents with cancer, who in comparison to younger patients have a higher cancer incidence and lower mortality reduction, have equal access to national cancer clinical trials. METHODS: The ethnic/racial distribution of 29,859 subjects < 20 years of age entered onto National Cancer Institute-sponsored clinical trials between January 1, 1991, and June 30, 1994, was compared with the expected distribution of patients of the same age in the United States. RESULTS: The Children's Cancer Group and Pediatric Oncology Group had 29,134 (97.6%) of the total study entries among < 20-year-old subjects during the 3.5 years of surveillance. The adult cooperative groups accounted for < 3% of the clinical trials entries in the 15-19-year age range. When analyzed nationally by region, the under-representation of the older adolescent subjects was universal. From other analyses, the two pediatric cooperative groups were estimated to have registered > 94% of the children < 15 years of age who were expected to have been diagnosed to have cancer, but only 21% of the cancer patients in the 15-19-year age group. CONCLUSIONS: The national pediatric cancer cooperative groups allow the majority of American children < 15 years of age and their families equal opportunity to access clinical cancer trials, regardless of race or ethnicity. Among patients 15-19 years of age, however, > 75% are not being enrolled by any cooperative group sponsored by the National Cancer Institute. Thus, older adolescents are disadvantaged with respect to access to the national clinical trials, regardless of their race or ethnicity.

Adolescent↗
PubMed1997

Leptin increases uncoupling protein expression and energy expenditure.

In ob/ob mice, leptin increases energy expenditure and sympathetic outflow to brown adipose tissue (BAT). To test whether the mechanism of increased energy expenditure may involve increased thermogenesis in BAT, we acclimated normal rats to thermoneutrality for 2 wk followed by leptin administration for 1 wk. Some rats were food restricted for 1 wk to the level of food consumption in the leptin-treated ad libitum-fed rats, and the same rats were both food restricted and administered leptin for a second week. We examined oxygen consumption and uncoupling protein (UCP) expression in BAT. Leptin increased oxygen consumption after the 5th and 6th days in ad libitum-fed rats and after the 4th, 5th, and 6th days in food-restricted rats. Leptin increased BAT UCP mRNA levels greater than twofold in both ad libitum-fed and food-restricted rats. These data demonstrate a leptin-induced increase in energy expenditure in nonmutant rodents and suggest that one mechanism by which leptin increases energy expenditure is through increased thermogenesis in BAT, including increased expression of UCP.

Acclimatization↗
PubMed1997

Use of alternative therapies for children with cancer.

OBJECTIVE: To compare the use of alternative therapy (AT) in families of children with cancer with its use in those with routine pediatric conditions. BACKGROUND AND RATIONALE: AT refers to healing practices such as therapeutic massage, acupuncture, and use of medicinal herbs that have become increasingly popular with the general public, but are not widely accepted by the medical profession. Although studies have investigated the use of AT in the families of both healthy children and children with cancer, no comparison of the incidence of its use between these two populations has been published. We hypothesized that AT was used more frequently among the families of children with cancer. METHODS: Using a prevalence survey design, we interviewed 81 parents of children with cancer attending a pediatric hematology/oncology clinic and 80 parents of children attending a continuity care clinic for routine check-ups and acute care. We explored the types of AT being used, the reasons for its use, and the frequency with which it was discussed with the patient's physician. RESULTS: 1) Overall, 65% of the cancer group were using AT, compared with 51% of the control group. This was not statistically significant. 2) Prayer, exercise, and spiritual healing were three AT practices most often used by the cancer group, and prayer, massage, and spiritual healing by the control group. 3) Discussion of AT with the physician varied according to group, with 53% of the cancer patients discussing its use; income level, with 59% of parents in the higher income group discussing its use; and ethnicity, with 47% of whites discussing its use. CONCLUSION: Use of AT is not limited to the families of children with life-challenging illnesses, but is commonly used by those of children with routine pediatric problems. Pediatricians need to be aware that their patients may not tell them about AT practices they are using in addition to prescribed treatment.

Adolescent↗