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Biomedical subjects

E Berry

Publications and source records attributed to E Berry.

At least 55 records · Page 3Linked to original sources

Outcome of subarachnoid haemorrhage. An analysis of surgical variables, cognitive and emotional sequelae related to SPECT scanning.

A group of 48 patients, consecutive apart from exclusions, from a 1-year series of 60 cases of aneurysmal subarachnoid haemorrhage (SAH), was reviewed, in respect of clinical and radiological features, surgical management, clinical outcome, psychological distress and psychometric status, the neuropsychological assessment being compared with a closely-matched group of controls, the postoperative assessment being accompanied by a single positron emission computed tomogram (SPECT) scan. A review of those features which might have been expected to have a bearing on cognitive outcome (CT abnormalities at the outset, angiographic vasospasm, operative aneurysmal leakage, temporary vessel occlusion) failed to show a significant difference on cognitive tests. There was, however, a cognitive deficit shown by the patient group as a whole, when compared with the controls. Thus, SAH itself, the initial insult, would appear to be the essential factor in the production of persistent cognitive deficits.

Activities of Daily Living↗

Cross-reactivity to porcine factor VIII of factor VIII inhibitors in patients with haemophilia in Australia and New Zealand.

BACKGROUND: Inhibitory antibodies which neutralise factor VIII develop in 10-20% of individuals with inherited haemophilia A and rarely as autoantibodies in normal individuals to cause acquired haemophilia. The antibodies are directed against human factor VIII but cross-react to varying degrees with porcine factor VIII. Porcine factor VIII can be used for treatment in individuals with low cross-reactivity. AIMS: To determine the cross-reactivity of factor VIII inhibitors between human factor VIII and porcine factor VIII, in a population of patients with inherited and acquired haemophilia A. Also, to determine whether patients with inherited haemophilia and inhibitors have a higher incidence of factor VIII gene inversion in intron 22. METHODS: Samples and data sheets from 43 patients with inherited and ten with acquired haemophilia were submitted from hospitals in Australia and New Zealand. Inhibitor levels to human and porcine factor VIII were measured by the Bethesda method in 39 with inherited and nine with acquired haemophilia A. RESULTS: Of 39 patients with inherited haemophilia A, cross-reactivity was 0% in 17 patients, 1-19% in six, 20-39% in 11 and 40-80% in five. In six of nine patients with acquired haemophilia cross-reactivity was < or = 7%. In inherited severe haemophilia A, the frequency of the intron 22 inversion was not greater in 37 study patients than in 28 patients without an inhibitor. CONCLUSIONS: Many patients in Australia and New Zealand with inhibitors to human factor VIII presently show a low or absent level of cross-reactivity to porcine factor VIII. These may respond to treatment with this concentrate at least in the short term. There remains a group of patients with high cross-reactivity who will respond only to recombinant factor VIIa or prothrombin complex concentrates.

Animals↗

Screening for Down's syndrome: changes in marker levels and detection rates between first and second trimesters.

OBJECTIVE: To monitor changes with gestation in levels of alpha-fetoprotein (AFP), free beta human chorionic gonadotrophin (F beta hCG) and pregnancy associated plasma protein-A (PAPP-A) in Down's syndrome pregnancies and to compare risks estimated in the first trimester with those obtained by routine screening in the second trimester for the same pregnancies. DESIGN: In each of 47 Down's syndrome pregnancies two maternal serum samples were obtained, one in the first trimester and one in the second trimester. Comparison of marker levels with 10,600 first trimester controls and a smaller sample of second trimester controls allowed case identification criteria based on optimum marker combinations to be developed and compared directly between trimesters. SETTING: Biochemical genetics laboratory. RESULTS: F beta hCG was an effective marker of Down's syndrome in both the first and second trimesters. PAPP-A levels were significantly reduced in trisomy 21 pregnancies in the first trimester only. Using a population model, these two markers in combination with maternal age gave an overall detection rate of 55% for a 5% false positive rate in the first trimester. For the paired first and second trimester samples, three of six cases classified as low risk by routine second trimester screening were classified as high risk by the first trimester screening protocol of F beta hCG/PAPP-A/maternal age. However, fifteen cases identified as high risk by routine second trimester screening were classified as low risk in the first trimester, a net loss in detection of 12 cases by first trimester screening. CONCLUSION: The data suggest that first trimester detection rates for Down's syndrome using a combination of F beta hCG and PAPP-A may vary with gestation and will be lower than those currently obtained by routine second trimester screening with AFP/hCG.

Biomarkers↗

The identification of bias in studies of the diagnostic performance of imaging modalities.

The demand for evidence-based healthcare is increasing nationally and internationally and it is equally necessary in both diagnostic and therapeutic practice. Evidence may be collected and combined by means of a systematic literature review of published and unpublished data on a well-defined topic. The output of such reviews is then available to guide health policy, influence good practice or direct research. Published guidelines are available on the performance of systematic reviews, especially those of randomized controlled trials. Although there is an extensive literature base of research data in diagnostic imaging there are few such trials, but it is still possible to perform systematic reviews. With the alternative study designs encountered it is important to be aware of the main threats to study validity. In this paper the biases likely to be encountered in studies of diagnostic performance are reviewed, with particular reference to diagnostic imaging tests. The biases are sub-divided into three categories. The first category is patient selection and covers the validity of generalizing results beyond the study population. The other two, concerning study design and execution and the interpretation of results, affect the likely validity of the results of a study. An understanding of these factors is an essential prerequisite for those undertaking or using a systematic literature review in the field of diagnostic imaging. The definitions form the foundations of a defensible review protocol.

Bias↗

Insulin-dependent diabetes mellitus and prenatal screening results: current experience from a regional screening programme.

From around 91,000 women having routine prenatal screening for Down's syndrome and neural tube defects between July 1992 and October 1995, 261 women were identified as having insulin-dependent diabetes mellitus (IDDM). Alpha-fetoprotein (AFP) and human chorionic gonadotrophin (hCG) levels were reduced in these women, with median levels of 0.89 and 0.91 multiples of the median (MOM), respectively. The IDDM patients had a median weight which was 6 kg heavier than that of non-IDDM women. After correction for maternal weight, the AFP and hCG levels in the IDDM patients were 0.98 and 0.92 MOM, respectively. In routine practice, using results which were not weight-corrected, the IDDM women were neither over- nor under-represented in the high-risk group for Down's syndrome, but showed a tendency to be under-represented in the high-risk group for neural tube defects.

Adolescent↗

Heat-stable and immunoreactive placental alkaline phosphatase in maternal serum from Down's syndrome and trisomy 18 pregnancies.

Placental alkaline phosphatase (ALP) activity was investigated in second-trimester maternal sera from 37 pregnancies with Down's syndrome, 28 pregnancies with trisomy 18, and in a series of 497 controls using a fluorimetric heat inactivation assay and specific immunoassay. After conversion of individual analyte values to multiples of the normal gestational median (MOM), no significant differences in total or placental ALP activities were found in the trisomy 21 or trisomy 18 cases (P > 0.01). In the Down's syndrome pregnancies, total ALP activity was 0.93 MOM, heat-stable ALP activity was 1.09 MOM, and placental ALP (by immunoassay) 0.96 MOM. In the trisomy 18 cases, total ALP activity was 0.90 MOM, heat-stable ALP activity was 0.79 MOM, and placental ALP (by immunoassay) 0.94 MOM. We conclude that neither total nor placental ALP activity is a useful marker for Down's syndrome or trisomy 18 screening.

Alkaline Phosphatase↗

Spatial distribution of femoral bone mineral in dual energy X-ray absorptiometry images: a possible technique to improve discrimination between normal and osteoporotic patients.

The measurement of bone mineral density (BMD) using dual energy X-ray absorptiometry (DXA) provides an indicator of subsequent risk of hip fracture, but because of the significant overlap of measurements obtained from osteoporotic and control groups its predictive power is limited. The radiographic technique of Singh grading for the assessment of femoral osteoporosis utilizes information about the distribution of trabecular bundles, but the morphological information available in the DXA image has not previously been analysed. In this study of DXA images from 64 individuals (32 controls and 32 classified as osteoporotic) a subjective grading technique analogous to Singh grading is proposed, and quantitative measurements are made of image features corresponding to two of the categories. Discrimination was assessed using receiver operating characteristic (ROC) curves: the best discrimination was by spinal BMD (Az = 0.85 +/- 0.05) a performance equalled by one of the new parameters; the subjective grading method (Az = 0.79 +/- 0.07) performed as well as measurements of BMD in the femur. These results suggest that although the alternative measures do not improve on the discrimination possible using spinal BMD, morphological information from the hip itself may in the future have a place in the assessment of bone quality.

Absorptiometry, Photon↗

Analysis of maternal serum alpha-fetoprotein and free beta human chorionic gonadotrophin in the first trimester: implications for Down's syndrome screening.

The aim of this study was to determine the maternal population, pregnancy, serum alpha-fetoprotein (AFP) and free beta subunit of human chorionic gonadotrophin (F beta hCG) parameters in a large series of women attending prenatal clinics before 15 weeks' gestation and to assess the practical problems of population screening for Down's syndrome in the first trimester using these markers. Serum samples were collected from 8600 women attending prenatal clinic booking visits. Maternal serum AFP and F beta hCG medians were calculated for each day of gestation (49-104 days), using both dates and ultrasound estimates of gestation. The effects of maternal weight, twin pregnancies, and threatened abortion on AFP and F beta hCG levels were analysed. The median age of the population was 27.1 years and the median weight 62.1 kg. Twenty-six per cent of samples were collected before 70 days and 50 per cent before 78 days' gestation. Eighty-nine per cent of all samples had gestational estimates by dates, 60 per cent by ultrasound and 52 per cent by both dates and ultrasound. The AFP median was 5 kU/l at 49 days, 5.9 kU/l at 70 days, and 17.9 kU/l at 100 days. The peak median F beta hCG level was 66.4 ng/ml at 64 days, falling to 20.6 ng/ml at 100 days' gestation. Both AFP and F beta hCG levels showed log Gaussian distributions but the standard deviation for AFP was 20 per cent greater than that found in the second trimester. AFP and F beta hCG levels showed an inverse relationship with maternal weight and were increased in twin pregnancies (1.68 and 1.97 multiples of the median, respectively). AFP and F beta hCG can be readily measured in a large screening population in the first trimester. Down's syndrome screening protocols based on these markers could be refined by the use of gestations in individual days but AFP is likely to be a less effective marker and detection rates are likely to be lower than in the second trimester. To realize the potential of first-trimester screening, more women should be encouraged to attend the prenatal clinic in early pregnancy and ultrasound dating should be carried out for all pregnancies at this stage.

Abortion, Threatened↗

Effects of low-dose estrogen oral contraceptives on weight, body composition, and fat distribution in young women.

OBJECTIVE: To determine prospectively whether the use of low-dose estrogen oral contraceptives (OC) is associated with changes in weight, body composition, or fat distribution. DESIGN: Anthropometric measurements were performed in 49 healthy young (16 to 21 years old) women before commencement of OC use (30 micrograms ethinyl estradiol [EF2] plus 75 micrograms gestodene) and after three and six treatment cycles. Thirty one age- and weight-matched women who were not using OC served as controls. SETTING: Outpatient gynecological clinic of Hadassah Medical Center, a tertiary level hospital, and the "Shilo" voluntary service for the prevention of unwanted pregnancy. MAIN OUTCOME MEASURES: Anthropometric measurements included body mass index (BMI), waist-to-hip girth ratio, and body composition (the percentage of body fat and water), estimated by mean of infrared interactance. RESULTS: In the group of OC users, baseline BMI, percent fat, percent water, and waist-to-hip girth ratio were 21.1 +/- 0.32 (kg/m2), 23.8% +/- 0.63%, 57.4% +/- 0.39%, and 0.73 +/- 0.01, respectively, and did not change significantly after six cycles (20.6 +/- 0.41 [kg/m2], 23.9% +/- 0.57%, 58.1% +/- 0.49%, and 0.72 +/- 0.03, respectively). These measurements were not significantly different when compared with the nonusers. Fifteen OC users (30.6%) gained weight (> 0.5 kg). Weight gain was due to a significant accumulation of fat (from 22.5% +/- 1.1% to 25.6% +/- 0.74%), whereas the percentage of body water remained stable. The waist-to-hip girth ratio also was not changed significantly. Similarly, 11 nonusers (35.4%) gained weight because of similar nonabdominal fat accumulation. Ten OC users (20.4%) lost weight (57 kg +/- 1.51 to 55.4 +/- 1.47 [mean +/- SEM]) and 6 nonusers (19.3%) also lost weight (59 kg +/- 1.42 to 57.3 +/- 1.92). In both groups the loss of weight was not associated with significant change in body composition. CONCLUSIONS: The use of low-dose OC (EE2 plus gestodene) was not associated with overall impact on weight, body composition, or fat distribution. However, when weight gain did occur during OC use, it was due to increase in body fat and not in volume of body water, and it was not associated with changes in fat distribution.

Adipose Tissue↗

A novel cytochrome c oxidase from Rhodobacter sphaeroides that lacks CuA.

Rhodobacter sphaeroides contains at least two different cytochrome c oxidases. When these bacteria are grown with high aeration, the traditional aa3-type cytochrome c oxidase is present at relatively high levels. However, under microaerophilic growth conditions or when the bacteria are grown photosynthetically, the amount of the aa3-type oxidase is greatly diminished and an alternate cytochrome c oxidase is evident. This alternate oxidase has been purified and characterized. The enzyme consists of three subunits by SDS-PAGE analysis (Mapp 45, 35, and 29 kDa). Two of the three subunits (Mapp 35 and 29 kDa) contain covalently bound heme C. Metal and heme analyses indicate that the oxidase contains heme C, heme B (protoheme IX), and Cu in a ratio of 3:2:1. Cryogenic Fourier transform infrared (FTIR) difference spectroscopy of the CO adduct of the reduced enzyme shows that the oxidase contains a heme-copper binuclear center and, thus, is a member of the heme-copper oxidase superfamily. In contrast to other members of this superfamily, however, this oxidase does not contain either heme O or heme A as a component of the binuclear center, but has heme B at this site. The single equivalent of Cu found in the oxidase is accounted for by the CuB component at the binuclear center. This suggests that this oxidase does not contain CuA, which is found in all other well-characterized cytochrome c oxidases. Both EPR and optical spectroscopic studies are consistent with this conclusion, also indicating that this oxidase does not contain CuA.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Membrane↗

Mild head injury--a positive approach to management.

It is estimated that 1.4 million patients each year attend Accident and Emergency (A&E) departments in the UK with a head injury. The vast majority are, in retrospect, diagnosed as a 'mild' injury. There is evidence to suggest that many develop short term morbidity and some long term problems. The incidence is unknown. Early recognition and treatment many hasten recovery. A national postal survey of A&E departments revealed a general unawareness for this morbidity. Written advice given to patients on discharge from the departments was exclusively concerned with the symptoms expected if serious complications developed. A description of the common symptoms of fatigue, poor memory and concentration were not given to the patients in a written format. Arrangements for follow up are, in the majority of hospitals, unstructured. We recommend a positive approach to the management and follow up of mild head injury. This should recognize the common problems experienced by these patients and cater for their needs. More interest and research is required into this aspect of head injury.

Craniocerebral Trauma↗

First trimester biochemical screening for trisomy 21: the role of free beta hCG, alpha fetoprotein and pregnancy associated plasma protein A.

The potential efficacy of screening for trisomy 21 in the first trimester, using maternal serum markers alpha fetoprotein, free beta human chorionic gonadotropin, unconjugated oestriol and pregnancy associated plasma protein A, was studied in an unselected population of women between the seventh and fourteenth week of gestation. Using a combination of alpha fetoprotein and free beta human chorionic gonadotropin, 53% of affected pregnancies could be identified at a false positive rate of 5%. Unconjugated oestriol and pregnancy associated plasma protein A levels were lower in cases of trisomy 21, but their inclusion with other markers did not significantly improve detection rate. Monitoring the same pregnancies also in the second trimester showed that screening in the first trimester identified the same cases as in the second. We conclude that first trimester screening using free beta human chorionic gonadotropin and alpha fetoprotein, is a viable possibility and will lead to detection rates in excess of 50%. Prospective studies are needed to confirm these observations.

Adolescent↗

Impact of a regional screening programme using maternal serum alpha fetoprotein (AFP) and human chorionic gonadotrophin (hCG) on the birth incidence of Down's syndrome in the west of Scotland.

OBJECTIVES: To evaluate the impact of a large scale population screening programme on the birth incidence of Down's syndrome in the west of Scotland over a 12 month period. METHODS: Biochemical screening for Down's syndrome using maternal serum alpha fetoprotein, chorionic gonadotrophin, and maternal age was offered to a pregnant population of 37,226 women in the west of Scotland between 1991 and 1992. The combined risk of Down's syndrome pregnancy was reported for each of the 30,084 women who opted for screening. RESULTS: When a threshold risk of 1:220 was used 1523 women (5.1% of the screened population) were assigned to the high risk group, of whom 1070 (70%) proceeded to diagnostic amniocentesis or midtrimester chorionic villus sampling. When multiple sources of ascertainment were used 37 Down's syndrome pregnancies were identified within the screened population, 26 (70%) of which were within the high risk group and 21 (57%) of which were prenatally diagnosed. In addition, three Down's syndrome pregnancies were diagnosed by first trimester chorionic villus sampling before biochemical screening. A further 10 Down's syndrome pregnancies were identified at birth, eight to women who had not had a screening test and two to women who had moved into the area, making a total of 50 Down's syndrome pregnancies in the whole pregnant population of 37,226. Thus the potential prenatal detection rate in the screened population was 70% (26/37), the actual prenatal detection rate in the screened population was 57% (21/37), and the overall prenatal detection rate in the total (screened and unscreened) population was 48% (24/50). CONCLUSION: Biochemical screening for Down's syndrome is practical and effective in routine clinical practice, enabling women to make an informed choice about prenatal diagnosis and providing better use of scarce resources when a suitable protocol is applied to the whole pregnant population. Its maximum potential for the reduction of the birth incidence of Down's syndrome is limited by incomplete uptake of screening and compliance with diagnostic testing in the high risk group.

Adolescent↗

First-trimester biochemical screening for fetal chromosome abnormalities and neural tube defects.

Alpha-fetoprotein (AFP), unconjugated oestriol (UE3), intact human chorionic gonadotrophin (intHCG), and the free beta subunit of chorionic gonadotrophin (F beta HCG) were investigated in a series of 21 chromosomally abnormal and 14 open neural tube defect pregnancies ascertained from a series of 14,000 prospectively collected maternal serum samples at 6-14 weeks' gestation. In 16 cases of Down's syndrome, significant reductions were found for AFP (0.65 multiples of the normal median) and UE3 (0.67 MOM). IntHCG levels were unaltered (0.97 MOM) but a significant increase was found for F beta HCG (1.96 MOM). Significant correlations were found for AFP and UE3 in the controls and for intHCG and F beta HCG in both the control and the Down's syndrome pregnancies. In a group of five trisomy 18 pregnancies, median MOMs were for AFP 0.71, for UE3 0.34, for intHCG 0.27, and for F beta HCG 0.15. None of 13 pregnancies with open neural tube defects at 8-13 weeks gestation had elevated maternal serum AFP levels, whereas matched second-trimester samples from the same pregnancies at 16-18 weeks gestation all had significantly elevated AFP levels. Thus, biochemical screening for chromosome abnormalities may be practicable in the first trimester using free beta human chorionic gonadotrophin in combination with AFP and maternal age. However, a separate screening protocol using AFP at 15-18 weeks gestation would still be required for effective detection of neural tube defects.

Biomarkers↗

Dexfenfluramine, fluoxetine, and weight loss among female carbohydrate cravers.

The consumption of excess calories as carbohydrates (CHO)-rich, protein-poor snacks characterizes the overeating of obese CHO cravers, premenstrual women, patients with Seasonal Affective Disorder, and former smokers. This specific appetite for CHOs may involve brain serotonin, as the synthesis and release of this neurotransmitter can increase following consumption of CHO-rich foods. To examine whether weight loss produced by serotoninergic drugs involves a selective reduction in CHO intake, obese females who consumed at least 30% of their daily calories from CHO-rich snacks were treated with dexfenfluramine ([DF] 15 mg b.i.d.); fluoxetine ([FL] 20 mg t.i.d.); or placebo (PL) for 12 weeks. Weekly weight loss for 25 of 29 PL completers was 0.22 kg +/- 0.06 (mean +/- SEM); for 21 of 28 DF completers, 0.56 +/- 0.08 kg; and for 18 of 30 FL completers, 0.58 +/- 0.09 kg (PL < DF = FL; p = .039). Seven FL subjects, 2 PL subjects, and 1 DF subject withdrew from the study due to side effects; other withdrawals were due to intercurrent illness or personal problems. Prior to treatment, subjects consumed over 40% of their daily CHO intake from snacks. Both of the drugs selectively decreased CHO snack intake (p < 0.05); DF, but not FL, also decreased meal CHO intake (p < .025). These results suggest that weight loss following treatment with serotoninergic drugs may relate to a selective decrease in CHO appetite.

Adult↗

An image processing technique for the identification of contact pixels applied to x-ray CT images of implanted hip prostheses.

Uncemented prosthetic joint implants used in orthopaedic surgery are usually coated with a porous surface to encourage bone ingrowth. Better contact between the endosteal bone and the porous surface improves ingrowth, and such contact may be increased if the joint further subsides into position in the first weeks following implantation. An image processing technique has been developed as part of a study undertaken to determine the effect of early subsidence on endosteal contact. The method provides a measure of the degree of contact between the surfaces from transverse x-ray CT images, but is suitable for application to any image with a similar intensity distribution.

Hip Prosthesis↗