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Biomedical subjects

G Buck

Publications and source records attributed to G Buck.

At least 19 recordsLinked to original sources
PubMed2006

Peritonitis after percutaneous endoscopic gastrostomy and jejunostomy: where there is smoke, there may not be fire.

Extensive reviews have been published regarding complications arising from percutaneous enteral access and ways of managing them. However, few data are available regarding unnecessary clinical interventions resulting from misinterpretation of benign postprocedural findings. We present here three representative cases of negative surgical abdominal cavity explorations for presumed peritonitis after percutaneous endoscopic gastrojejunostomy and jejunostomy.

Adult↗
PubMed2005

Efficacy and safety of cholesterol-lowering treatment: prospective meta-analysis of data from 90,056 participants in 14 randomised trials of statins.

BACKGROUND: Results of previous randomised trials have shown that interventions that lower LDL cholesterol concentrations can significantly reduce the incidence of coronary heart disease (CHD) and other major vascular events in a wide range of individuals. But each separate trial has limited power to assess particular outcomes or particular categories of participant. METHODS: A prospective meta-analysis of data from 90,056 individuals in 14 randomised trials of statins was done. Weighted estimates were obtained of effects on different clinical outcomes per 1.0 mmol/L reduction in LDL cholesterol. FINDINGS: During a mean of 5 years, there were 8186 deaths, 14,348 individuals had major vascular events, and 5103 developed cancer. Mean LDL cholesterol differences at 1 year ranged from 0.35 mmol/L to 1.77 mmol/L (mean 1.09) in these trials. There was a 12% proportional reduction in all-cause mortality per mmol/L reduction in LDL cholesterol (rate ratio [RR] 0.88, 95% CI 0.84-0.91; p<0.0001). This reflected a 19% reduction in coronary mortality (0.81, 0.76-0.85; p<0.0001), and non-significant reductions in non-coronary vascular mortality (0.93, 0.83-1.03; p=0.2) and non-vascular mortality (0.95, 0.90-1.01; p=0.1). There were corresponding reductions in myocardial infarction or coronary death (0.77, 0.74-0.80; p<0.0001), in the need for coronary revascularisation (0.76, 0.73-0.80; p<0.0001), in fatal or non-fatal stroke (0.83, 0.78-0.88; p<0.0001), and, combining these, of 21% in any such major vascular event (0.79, 0.77-0.81; p<0.0001). The proportional reduction in major vascular events differed significantly (p<0.0001) according to the absolute reduction in LDL cholesterol achieved, but not otherwise. These benefits were significant within the first year, but were greater in subsequent years. Taking all years together, the overall reduction of about one fifth per mmol/L LDL cholesterol reduction translated into 48 (95% CI 39-57) fewer participants having major vascular events per 1000 among those with pre-existing CHD at baseline, compared with 25 (19-31) per 1000 among participants with no such history. There was no evidence that statins increased the incidence of cancer overall (1.00, 0.95-1.06; p=0.9) or at any particular site. INTERPRETATION: Statin therapy can safely reduce the 5-year incidence of major coronary events, coronary revascularisation, and stroke by about one fifth per mmol/L reduction in LDL cholesterol, largely irrespective of the initial lipid profile or other presenting characteristics. The absolute benefit relates chiefly to an individual's absolute risk of such events and to the absolute reduction in LDL cholesterol achieved. These findings reinforce the need to consider prolonged statin treatment with substantial LDL cholesterol reductions in all patients at high risk of any type of major vascular event.

Cause of Death↗
PubMed2004

Adverse impact of bone marrow transplantation on quality of life in acute myeloid leukaemia patients; analysis of the UK Medical Research Council AML 10 Trial.

The increasing success of intensive consolidation chemotherapy (CCT) as an alternative to bone marrow transplant (BMT) in acute myeloid leukaemia (AML) necessitates comparison of the impact on quality of life (QoL) of these two treatment modalities. Most QoL studies following BMT involve small patient numbers and provide ambivalent results. The present study examines QoL in a large number of patients 1 year from the end of treatment within the United Kingdom Medical Research Council (UK MRC) AML10 trial of BMT versus CCT. Allogeneic-BMT (Allo-BMT) was observed to have an adverse impact on most QoL dimensions compared with Autologous-BMT (A-BMT) and CCT. More patients receiving BMT had mouth dryness problems and worse sexual and social relationships, professional and leisure activities than CCT patients. QoL in A-BMT patients was less impacted than Allo-BMT. Intention-to-treat analysis showed similar results. These results indicate that a reconsideration of treatment strategies is warranted, and that further, good prospective studies are needed to evaluate more clearly the effects of these treatments in long-term survivors.

Adolescent↗
PubMed2002

Experience and extensions to the ASM2 family of models.

The development of ASM2 has created a complex model for biological phosphorus removal. Most of the published work on calibrating this model has focused on the design of experiments to maximise information with which to calibrate the model, or the use of hourly data collected around and within an aeration tank. But many sewage works do not collect such data, nor have such instrumentation. The application of ASM2 with sparse data collected at a low frequency, and mostly only input-output, is considered in this paper, based on data collected at a Swedish sewage works. This paper shows that ASM2 can be calibrated with such measurements. This paper also looks at a modification to ASM2d to better handle heterotrophic usage of volatile fatty acids, and the use of this model to study the effects of large increases in in-sewer storage on sewage treatment works. Concern about the generation of large quantities of VFAs, and their effect on the sewage treatment processes, was unfounded.

Calibration↗
PubMed2001

Prediction of fetal anemia with Doppler measurement of the middle cerebral artery peak systolic velocity in pregnancies complicated by maternal blood group alloimmunization or parvovirus B19 infection.

OBJECTIVES: To confirm the relationship between the middle cerebral artery peak systolic velocity (MCA PSV) and hemoglobin values in fetuses at risk for anemia (due to maternal blood group alloimmunization or parvovirus B19 infection) and to investigate the clinical value of this method in the management of these pregnancies regardless of previous transfusions. SUBJECTS AND METHODS: Forty singleton pregnancies, 30 affected by alloimmunization and 10 by intrauterine parvovirus B19 infection, were referred to our tertiary center between 1998 and 2000. All cases underwent Doppler measurement of the MCA PSV immediately before fetal blood sampling and just before and after intrauterine transfusion. Hemoglobin determination was always performed after diagnostic cordocentesis, before starting and after terminating fetal transfusion. RESULTS: Overall, we performed 165 fetal blood samplings (hemoglobin values) and obtained 165 corresponding MCA PSV values, 140 in pregnancies complicated by red-cell alloimmunization and 25 by parvovirus B19 infection. In order to adjust for the effect of gestational age on the measurements, the data were expressed in multiples of the median (MoM). We found a good correlation between MCA PSV MoM and Hb MoM in both groups (alloimmunization, r2 = 0.6; y = 2.21 - 1.41 x + 0.24 x 2; parvovirus infection, r2 = 0.68; y = 2.09 - 0.58 x - 0.16 x 2). The reduction of post-transfusion MCA PSV values was statistically significant ( P < 0.0001). Using a threshold of 1.29 for MoM PSV, the sensitivity and the specificity of MCA pulsatility indices on pretransfusion values in predicting any degree of fetal anemia (Hb < or = 0.84 MoM) were 73.1% and 81.5% in the alloimmunization group and 100% and 100% in the parvovirus infection group, respectively. CONCLUSION: We can confirm the presence of an inverse correlation between MCA PSV measurements and hemoglobin values in fetuses at risk for anemia due to maternal blood group alloimmunization and fetal parvovirus B19 infection. The MCA PSV is a reliable method for the prediction of anemia not only in fetuses before the first intrauterine transfusion, but also in those which have undergone one or more transfusions, with good sensitivity and specificity in both groups of fetuses at risk.

Anemia↗
PubMed2001

Exposure to Schistosoma mansoni infection in a rural area in Brazil. II: household risk factors.

A number of studies have pointed out the potential importance of the household in the transmission of schistosomiasis. The clustering of domestic activities associated with water collection, storage, and usage can result in the sharing of transmission sites and infective water contact behaviours. In this study, we employed a variance component method to estimate effects due to individual risk factors and shared residence on the variance in faecal egg counts during Schistosoma mansoni infection. A suite of covariates, which included demographic, socioeconomic, water supply, and water contact behaviour terms, contributed 15% to the variance in faecal egg counts. Shared residence alone accounted for 28% of the variance in faecal egg excretion. When both the suite of covariates and shared residence were considered in the same model, shared residence still contributed 22% to the variance in infection intensity. These results point to the importance of shared residence as a means of capturing the complex interrelationship between shared demographic, socioeconomic, physical environmental, and behavioural factors that influence transmission of schistosomiasis at the household level.

Adolescent↗
PubMed2000

Controlling for the effects of hospital attributes. The efficacy of factor analysis.

PURPOSE: The assessment of risk often requires controlling for the potentially confounding effects of hospital attributes. This paper (1) describes the use of factor analysis as a means of quantifying hospitals' obstetrical care, and (2) compares within respective unconditional logistic regression models the performance of factor scores with that of the "obstetrical unit service level" (OBUSL) classification as defined by the American Hospital Association (AHA).METHODS: A principal components factor analysis was performed on fourteen variables from 116 hospitals in Upstate New York. These variables, descriptive of hospitals' obstetrical care, were obtained from the 1992 AHA's Annual Survey of Hospitals. Factor scores were correlated with the OBUSL. Factor scores were matched to 89,341 women with vaginal deliveries in the 1992 Live Birth Registry for Upstate New York. The performance of factor scores and the OBUSL variable was compared in separate unconditional logistic regression analysis designed to identify determinants of obstetrical anesthesia care.RESULTS: Principal components factor analysis with varimax rotation identified three factors which were strongly correlated with hospital OBUSL. In a model which included the OBUSL variable, the adjusted odds ratios (AORs) or receiving an epidural for vaginal delivery were lower among mothers with Medicaid, HMO, or no insurance coverage (i.e., 0.45 [95% CI, 0.43-0.48], 0.68 [0.64-0.71], and 0.44 [0.38-0.52], respectively) than among those with private coverage. In a model in which factor scores were substituted for the OBUSL variable, respective AORs were 0.48 (0.45-0.52), 0.63 (0.60-0.66), and 0.45 (0.39-0.53).CONCLUSIONS: Factor analysis provided a parsimonious description of 14 hospital variables, was useful as a control within the regression model, and may prove similarly useful in other areas of clinical care.

Journal Article↗
PubMed2000

Measuring functional status and family support in older school-aged children with cerebral palsy: comparison of three instruments.

OBJECTIVE: To compare a pediatric and an adult version of a functional status measure and a family support measure for assessing school-age children with spastic cerebral palsy. DESIGN: A prospective study involved functional status measurements using the Pediatric Functional Independence Measure (WeeFIM), the Adult Functional Independence Measure (FIM), and a family support measure, the Amount of Assistance Questionnaire (AAQ). PARTICIPANTS: The feasibility sample consisted of 47 children aged 2 to 12 yrs with cerebral palsy. The study sample consisted of 20 children aged 7 to 16 yrs with spastic cerebral palsy (50% diplegia, 50% quadriplegia). INTERVENTIONS: Initial assessment interview included the WeeFIM, developmental milestones, educational achievement information, and the AAQ. Within 1 month, a follow-up phone interview using the FIM was completed. MAIN OUTCOME MEASURE: The WeeFIM and FIM measure independence in self-care, sphincter control, mobility, locomotion, communication, and social cognition. The AAQ measures the time and assistance required by a child in essential daily tasks. RESULTS: Pearson's correlation coefficient exceeded .97 for WeeFIM and FIM total score in the total sample as well as in two subgroups of children: those with diplegia and quadriplegia. Total scores in WeeFIM and FIM as well as domain scores were significantly different between children with diplegia and quadriplegia. Parental amount of assistance on the AAQ was significantly correlated with WeeFIM and FIM scores. CONCLUSION: Either the WeeFIM or FIM can be used for monitoring functional status through adolescence in children with spastic cerebral palsy. Functional limitations are highly related to requirements for parental assistance.

Activities of Daily Living↗
PubMed2000

Penicillin minimum inhibitory concentration drift in identical sequential Streptococcus pneumoniae isolates from colonized healthy infants.

We monitored the timing of acquisition of nasopharyngeal colonization of Streptococcus pneumoniae in 125 healthy infants during their first 2 years of life. S. pneumoniae was isolated at least once from 59 (47%) of 125 infants aged between 2 and 18 months. Twenty-four infants (19%) were colonized with penicillin-resistant S. pneumoniae at some time during the study. During the course of this investigation, we identified sequential pneumococcal isolates of the same serotype from 5 infants, in which the penicillin minimum inhibitory concentration (MIC) increased over time. For 4 of the 5 infants, sequential isolates were identical, as determined by pulsed-field gel electrophoresis. Sequential S. pneumoniae nasopharyngeal isolates from some healthy infants demonstrated drift in penicillin MIC values over time, from penicillin-susceptible to penicillin-resistant.

Child, Preschool↗
PubMed1999

Relation of Lake Ontario fish consumption, lifetime lactation, and parity to breast milk polychlorobiphenyl and pesticide concentrations.

Lactating female members and spouses of male members of the New York State Angler Cohort who agreed to provide breast milk samples were the subjects of this study. Questionnaires were provided to participants focusing on Lake Ontario fish consumption, reproductive history, and lactation history. Milk samples were analyzed for 77 polychlorinated biphenyls (PCB) congeners, 1,1-dichloro-2,2-bis (p-chlorophenyl)-ethylene (DDE), a metabolite of dichlorodiphenyltrichloroethane (DDT), hexachlorobenzene (HCB), and 1,1a,2,2,3,3a, 4,5,5,5a,5b,6-dodecachlorooctahydro-1,3, 4-methano-1H-cyclobuta[cd]pentalene (Mirex). The percentage of samples with quantifiable levels, above the limit of detection (LOD), varied among the individual congeners from 10 to 100%. Nine PCB congeners (designated by their IUPAC No.) and DDE were found in all of the 100 samples analyzed. These include the following, in decreasing order of concentration: DDE>153>138>180>118>187>188>177>200. Total PCB concentrations were estimated by taking the sum of the concentrations of all PCB congeners (up to 77 congeners) above their respective LOD in a given sample. PCB concentrations increased with increasing concentration of milk lipid. Lipid adjusted PCB concentrations increased as a function of maternal age. PCB congener profiles in milk favored the higher chlorinated congeners, with the four highest congeners having 5 to 7 chlorine atoms. Fish eaters had a significantly higher level of several major PCB congeners with congeners 153 and 138 being 1.36 and 1.34 times higher, respectively. PCB and DDE concentrations, expressed on a lipid basis, varied inversely with parity. The total number of months of lifetime lactation varied inversely with the total PCB concentration in breast milk. A similar relationship was evident for DDE. These data are of use for risk assessment in estimating the relative exposure to these environmental contaminants in breast fed infants whose mothers consumed contaminated Lake Ontario fish.

Adult↗
PubMed1999

Treatment of fetal erythroblastosis by intravascular transfusions: outcome at 6 years.

OBJECTIVE: To assess 6 years' neurologic outcome of a complete cohort of survivors of intrauterine intravascular transfusions. METHODS: From January 1986 to December 1991, 136 intravascular transfusions were performed in 43 fetuses presenting with signs of severe erythroblastosis. Before the initial transfusion, 11 of 43 fetuses had some degree of hydrops fetalis, and hemoglobin values ranged between 1.5 and 10.7 g/dL. Neurologic outcome of a complete cohort of 35 long-time survivors was assessed for up to 6 years by reviewing the hospital charts and questionnaires sent to the family physicians or pediatricians. RESULTS: Long-time follow-up was available in all survivors with hydrops at initial transfusion (seven of seven) and in 23 of 28 survivors without hydrops. Only one of 35 survivors had mild psychomotoric disabilities up to 1 year of age, but was free of sensorineural problems on further examination. In a second case, delayed speech development was observed. Fetuses presenting with hydrops fetalis before initial transfusion tended to have a higher perinatal mortality and had a significantly higher rate of preterm delivery (P = .03). However, moderate or severe neurologic impairment was never observed, even when severe cases with hydrops fetalis or extremely low hemoglobin levels were included. CONCLUSION: Treatment of severe fetal erythroblastosis by intrauterine intravascular transfusions is associated with a favorable neurologic long-time outcome.

Blood Group Antigens↗
PubMed1998

Maternal cigarette smoking, regular use of multivitamin/mineral supplements, and risk of fetal death: the 1988 National Maternal and Infant Health Survey.

Data from the 1988 National Maternal and Infant Health Survey were used to examine whether regular use of multivitamin/mineral supplements could modify the relation between maternal smoking and fetal death. Maternal smoking was defined as the self-reported average number of cigarettes smoked after recognition of pregnancy. Regular supplement use was defined as use of multivitamin/mineral supplements for at least 3 days per week during the 3 months before and/or after recognition of pregnancy. The sample comprises 12,465 singleton pregnancies, including 9,402 livebirths and 3,063 fetal deaths. Odds ratios were derived from logistic regression analyses after adjustment for a number of demographic and reproductive variables. Major findings are that 1) smoking increased the risk of fetal death; 2) regular supplement use either before or after recognition of pregnancy did not affect the risk of fetal death in the absence of maternal smoking; 3) odds ratios for fetal death among smoking women who regularly used supplements were generally smaller than those for women who did not regularly use supplements but who smoked a comparable number of cigarettes; and 4) a significant negative excess risk due to interaction was observed among women who regularly used supplements before recognition of pregnancy and smoked 20 or more cigarettes a day. These findings suggested that regular multivitamin/mineral supplement use might reduce the risk of fetal death associated with maternal smoking.

Adult↗
PubMed1998

Can regular multivitamin/mineral supplementation modify the relation between maternal smoking and select adverse birth outcomes?

PURPOSE: The purpose of this study was to examine whether or not regular multivitamin/mineral supplementation can modify the relation between maternal smoking and preterm birth (gestational age < 37 weeks), very-low-birthweight (VLBW) (< 1500 g), moderately-low-birthweight (MLBW) (< 2499 g), or small-for-gestational-age (SGA) (< 10th percentile of birth weight for gestational age). METHODS: Live birth data from the 1988 National Maternal and Infant Health Survey (NMIHS) were used for the analysis. Maternal smoking referred to self-reported average number of cigarettes smoked after recognition of pregnancy, while regular multivitamin/mineral supplementation referred to use of multivitamin/mineral supplements for at least three days per week during the three months before and/or after recognition of pregnancy. Sample sizes included 9402 singleton infants for the analysis of preterm birth, 9395 for very or moderately low birthweight, and 9363 for small-for-gestational-age. Odds ratios were derived from logistic regression analyses after adjusting for a number of demographic and reproductive variables. RESULTS: Major results include: 1) increased risks for the adverse outcomes studied were observed among smoking women; 2) no effect of regular multivitamin/mineral supplementation in the absence of maternal smoking was revealed; and 3) relative excess risks due to interaction at different smoking levels and overall interactions between smoking and supplementation were not observed. CONCLUSIONS: These results suggest that regular multivitamin/mineral supplementation does not minimize the adverse effects associated with maternal smoking.

Adult↗
PubMed1998

Findings from the American College of Epidemiology's survey on Ethics guidelines. The American College of Epidemiology Ethics and Standards of Practice Committee.

PURPOSE: A survey to establish both the need and subject areas for a possible new set of ethics guidelines for epidemiologists was conducted among a random sample of 300 North American (Canada, Mexico, and United States) members of three major United States-based professional epidemiology organizations. METHODS: An 88% response rate revealed wide agreement on topics to be included in any new set of guidelines, but uncertainty prevailed about the need for new guidelines; 41% agreed that there was a need to develop a new set, 43% had no opinion, and 16% disagreed. RESULTS: There was almost no difference in preferences between men and women for topics to be included in a new set of guidelines, or between those aware or unaware of extant ethics guidelines in epidemiology. Fifty-four percent were aware of such guidelines and only 29% of these said they could describe the content of the guidelines. CONCLUSION: More needs to be done to evaluate the utility of ethics codes in epidemiology.

Data Collection↗
PubMed1998

Side effects and discontinuation rates of intrauterine contraceptive device use in the Jilin Province of China.

Data from the Fertility and Contraception Survey undertaken in the Jilin Province in 1988 were used to examine both the rates of side effects and discontinuation among women using intrauterine devices (IUDs). The results show that among the 1,912 first time IUD users, the combined side effects rate comprising excessive bleeding, irregular menstruation, or abdominal pain was 11.7 percent; 0.2 percent of first time IUD users became seriously ill due to faulty insertion techniques. The gross cumulative failure rates at the end of the first, second and third year following insertion were 5.3%, 9.2% and 11.9%, respectively. Total gross cumulative discontinuation rates for these three time periods were 9.9%, 19.3%, and 28.3%, respectively. It was also found that selected social and service factors such as nationality, farm/non-farm residency, medical institution where the insertion was provided, interval between the data of last pregnancy and the date of the insertion, and the number of children at the time of insertion were associated with IUD-related side effects and/or discontinuation. The findings are further discussed with respect to governmental intervention in regulating family size, in terms of the reliability of the self-reported data, and other IUD related effects.

Abdominal Pain↗
PubMed1998

Prenatal diagnosis of heterozygosity for biotinidase deficiency by enzymatic and molecular analyses.

Biotinidase deficiency is characterized by neurological and cutaneous abnormalities that can be prevented or ameliorated by oral biotin therapy. A child with biotinidase deficiency went undiagnosed for a long period and has irreversible neurological deficits despite biotin treatment. This child is homozygous for the most common mutation (G98:d7i3) found in symptomatic children with the disorder. The parents insisted on having prenatal diagnosis in a subsequent pregnancy to alleviate their anxiety about having another affected child. Mutation analysis of DNA obtained directly from amniotic fluid and from cultured amniocytes revealed that the fetus was heterozygous for the mutation. Maternal cell contamination of the amniocytes was excluded by genotype analysis. Biotinidase activity in extracts of cultured amniocytes revealed 40 per cent of mean normal activity. At birth, the infant was confirmed to be heterozygous by serum enzyme analysis. This is the first report of the use of molecular analysis for the prenatal diagnosis for biotinidase deficiency.

Amidohydrolases↗
PubMed1998

Metabolic crisis: hyperemesis gravidarum.

Nausea and vomiting during pregnancy affect approximately 50% to 70% of all pregnant women. Although most cases of nausea and vomiting in pregnancy resolve spontaneously and are not associated with compromised nutritional status, a small percentage of cases progress to hyperemesis gravidarum (severe nausea and vomiting during pregnancy). Hyperemesis gravidarum is a serious disorder that can lead to weight loss, dehydration, electrolyte disturbances, and occasionally death if improperly treated or left untreated. The article summarizes recent research on hyperemesis gravidarum, focusing on the definition, etiology, epidemiology, and current treatment of symptoms.

Adult↗