A BRCA1 founder mutation, identified with haplotype analysis, allowing genotype/phenotype determination and predictive testing

We searched for a founder mutation in a population from one geographic region of Norway with prevalent breast/ovarian cancer families. We sampled 33 breast/ovarian cancer families and determined haplotypes of four markers linked to the BRCA1 region. Of the affected 33 index women, 13 (39.4%) shared one haplotype. In five (15% of total), an identical mutation was indicated by an abnormal truncated protein test (PTT) of exon 11 and shown to represent a 1675delA mutation. In the other index women, PTT of exon 11 showed no abnormality. No other BRCA1 founder mutation of this prevalence is likely because no other haplotype was more frequent in affecteds than in controls. All families with the 1675delA mutation in this geographic region may be considered as part of one large kindred. This allows a genotype-phenotype correlation to be precisely determined and used in genetic counselling for predictive testing within this kindred. Identification of identical haplotypes between unrelated affected individuals may be used to estimate the extent of founder effects for any mapped disease, without knowledge of the specific founder mutation.     

An aetiological profile of short stature in the Indian subcontinent

To determine whether the genetic background of the insulin-producing beta cells of the pancreas contributes to autoimmune diabetes susceptibility, we have used a model of the disease based on transferring spleen cells from nonobese diabetic (NOD) <--> C57BL/6 (B6) embryo aggregation (EA) chimeras into B6 and NOD irradiated mice. Insulitis and diabetes could be induced into both B6 and NOD hosts, albeit with low incidence. Cyclophosphamide (CY) treatment, known to accelerate diabetes in prediabetic NOD mice, was found to increase diabetes incidence up to 50-60% in both B6 and NOD mice reconstituted with chimeric splenocytes, while diabetes did not occur in CY-treated B6 mice reconstituted with B6 splenocytes. We conclude that the genetic make-up of the target organ does not affect the final stage of the pathogenesis of insulin-dependent diabetes mellitus.     

Long-term compliance of laryngectomized patients with a specialized pulmonary rehabilitation device: Provox Stomafilter

New Zealand mortality records for the years 1980 to 1993 were analysed to estimate the aggregate burden of infectious disease using a recoding of ICD-9 codes to identify deaths with infectious aetiology. The recoding scheme was modified from one developed by US CDC, which used expert panels to assign ICD codes to categories dependent on the proportion of the code attributable to infection. ICD-9 Chapter One ('Infectious and parasitic diseases') accounted for only 0.7% of total deaths. Following recoding, this proportion increased tenfold, with 6.9% of deaths attributable to infectious disease. This proportion was stable or declined only slowly between 1980 and 1993. While rates varied by age, gender and ethnicity, the results indicate that infectious disease still accounts for a substantial proportion of the burden of disease in New Zealand.     

Availability of PSC833, a substrate and inhibitor of P-glycoproteins, in various concentrations of serum

BACKGROUND: P-glycoproteins are membrane-associated transporters that can render cells resistant to a variety of chemotherapeutic drugs. Reversal agents are (preferably nontoxic) drugs that can inhibit these P-glycoproteins and thereby overcome multidrug resistance. PSC833, a cyclosporin A analog, is a reversal agent that has shown potential in in vitro experiments and in clinical trials. We tested PSC833 to determine whether it is a transported substrate of human and murine P-glycoproteins associated with multidrug resistance (encoded by the human MDR1 gene and its murine homolog, mdr1a) and whether it can completely inhibit these P-glycoproteins under simulated in vivo conditions. METHODS: Monolayers of polarized LLC-PK1 pig kidney cells transfected with complementary DNA containing either MDR1 or mdr1a sequences were used to measure the directional transport of P-glycoprotein substrates under various serum conditions. RESULTS: In contrast to two previous studies, we found that PSC833 is transported by both the MDR1 and the mdr1a P-glycoproteins, albeit at a low rate. PSC833 has a very high affinity for the MDR1 P-glycoprotein, and its Michaelis constant (Km) for transport is 50 nM, fourfold lower than for cyclosporin A. Inhibition of drug transport by PSC833 is approximately eightfold less effective in 100% fetal bovine serum than in tissue culture medium containing 10% serum. The concentration of PSC833 necessary to fully inhibit transport of digoxin and paclitaxel (Taxol) under complete (i.e., 100%) serum conditions is higher than the plasma concentrations achieved in clinical trials. CONCLUSIONS: Although PSC833 binds efficiently to the MDR1 P-glycoprotein and is released only sluggishly, the high concentrations of PSC833 necessary to inhibit this P-glycoprotein under complete serum conditions in our in vitro system suggest that it may be difficult for PSC833 alone to produce total inhibition of P-glycoprotein activity in patients.     

Psychology and "the Babe"

Along with the rapid biomedical development of prenatal screening tests, target groups' attitudes and decision-making about, and the acceptance of, screening procedures have come into focus. To understand users' decision-making, it is essential to understand users' knowledge and perceptions of a procedure. The aim of this study was to examine Finnish women's knowledge and perceptions of, and stated reasons to participate in, two prenatal screening tests: serum screening and mid-trimester ultrasound screening. Subjects (n=1035) for the serum screening survey were catered for in the maternity care centres of two Finnish towns, where serum screening is available for all pregnant women. After one reminder, 88 per cent returned the questionnaire. Subjects (n=497) for the mid-trimester ultrasound screening survey were catered for in the obstetrical and gynaecological outpatient clinic of the city hospital of another town; the response rate was 85 per cent. Women's perceptions of the studied prenatal screening tests, serum screening and mid-trimester ultrasound screening, differed significantly, even though both are used to detect fetal malformations. Serum screening was far more often perceived to be connected with finding diseases or abnormalities than ultrasound screening. Another interesting finding was that the stated reasons for screening in general and the subjective reasons for participation were different. Reassurance was the personal reason most often mentioned in both the serum screening and the ultrasound group. Almost all women had the most superficial knowledge about serum screening; they knew whether it had been offered and that it is done to screen for Down syndrome. The greatest gaps in knowledge concerned the sensitivity of serum screening, its use in screening for congenital nephrosis, and diagnostic tests and their risks. Knowledge was poorer among women without a high school education. When counselling women about prenatal screening tests, more emphasis should be given to the sensitivity of serum screening, all of its screening uses, and the possible diagnostic tests and their risks. The fact that ultrasound screening can detect conditions which may lead to the possibility of a selective abortion should also be explained more fully.     

Papillary thyroid carcinoma oncogene (RET/PTC) alters the nuclear envelope and chromatin structure

Current evidence suggests the papillary thyroid carcinoma oncogene (RET/PTC) generates papillary thyroid carcinomas in one genetic step. We tested a resulting prediction that RET/PTC expression in thyroid epithelium should be sufficient to cause the changes in nuclear morphology diagnostic of this tumor. Primary cultures of human thyroid epithelial cells were infected with a RET/PTC retroviral construct. Morphological scoring by two independent cytopathologists shows RET/PTC expression by immunohistochemistry to be highly associated (p < 0.0001) with an irregular nuclear contour and a euchromatic appearance compared with non-expressing cells in the same cultures. The altered nuclear morphology is not due to gene transfer or transformation per se as primary thyroid cell cultures infected with a retroviral H-RAS construct differ from RET/PTC-infected cells by showing round nuclear envelopes and coarser chromatin, as determined by the independent scoring of two cytopathologists (p < 0.0001). In addition, RET/ PTC-transfected cells appear to disperse, whereas RAS-transfected cells grow as discrete colonies. The results provide additional support for the hypothesis that RET/PTC is sufficient to cause papillary thyroid carcinomas. A signaling pathway downstream of RET/ PTC leads to restructuring of the nuclear envelope and chromatin, and the signal does not depend entirely, if at all, on a RAS pathway.     

Influence of tidal volume on the distribution of gas between the lungs and stomach in the nonintubated patient receiving positive-pressure ventilation

The technique involving filtration of diluted blood enables the separate analysis of the flow properties of different cell subpopulations. This study was designed to assess the changes occurring in the flow properties and function of blood cells in stored bank blood and salvaged blood compared to patient blood in a given clinical situation. We measured hydrogen peroxide production by neutrophils and the filterability, through 5 microm Nucleopore filters, of isolated red blood cells and of diluted blood. Samples were obtained from patients undergoing aortic surgery and blood intended for transfusion: either salvaged during surgery or stored bank blood. Both salvaged and bank blood were much less filterable than patient blood, with reduced deformability of both red and white blood cells. However, salvaged blood contained highly activated neutrophils with a prolonged transit time of the 'fast-flowing' cells in the analysis compared to bank blood. Bank blood contained significantly more particles which acted as pore-blockers. Cells in bank and salvaged blood therefore have markedly abnormal flow and biochemical properties compared to patient blood.     

Increased platelet responsiveness following coronary stenting. Heparin as a possible aetiological factor in stent thrombosis

AIMS: Platelet activation may be a determinant of thrombotic and restenotic complications following intracoronary stenting. In order to measure the effect of stenting on platelet activation antigen expression we used whole blood flow cytometry in 18 patients undergoing Palmaz-Schatz stenting (treated with full anticoagulation) and compared these with a group of 18 patients undergoing elective angioplasty. The effects of low molecular weight heparin and unfractionated heparin on platelet behaviour were also studied, both in vitro and in vivo to determine the contribution of prolonged heparin therapy to platelet activation following stenting. METHODS AND RESULTS: Fibrinogen binding to activated GPIIb-IIIa, and surface expression of P-selectin, GPIb and GPIIb-IIIa antigens were measured in unstimulated peripheral blood samples (rest) and on stimulation with adenosine diphosphate (0.1-10 micromol x 1(-1)) and thrombin (0.02-0.16 U x ml(-1)). No changes were seen in resting samples following angioplasty or stenting. Agonist responsiveness was unaltered after angioplasty, but in stented patients antigen expression in response to thrombin was significantly reduced (P< or =0.04), whilst the adenosine diphosphate response was significantly increased (P=0.01). Similar effects were observed in patients with unstable angina treated with either low molecular weight heparin or unfractionated heparin in vivo. In vitro, both unfractionated and low molecular weight heparin inhibited thrombin-induced platelet activation, but stimulation of adenosine diphosphate responses was more marked with unfractionated than low molecular weight heparin. CONCLUSIONS: There was a significant increase in platelet responsiveness to adenosine diphosphate following intracoronary stenting in patients treated with conventional anticoagulants. This was probably a consequence of treatment with heparin. Activation of platelets by heparin may explain the increased rate of stent thrombosis in patients treated with anticoagulant therapy. Low molecular weight heparins stimulate platelets less than unfractionated heparin.     

Arsenic levels in drinking water and the prevalence of skin lesions in West Bengal, India

OBJECTIVE: To evaluate the suitability and efficiency of human follicular fluid (HFF) as a protein supplement in human IVF programs. DESIGN: Comparative study of the effects of HFF and other protein supplements on the in vitro development of mouse oocytes and on the pregnancy rate in human IVF programs. SETTING: In Vitro Fertilization Center, Hanna Women's Clinic, Seoul, Korea. PATIENT(S): Three hundred twenty-seven patients (388 cycles) who were down-regulated with GnRH agonist and stimulated with hMG. INTERVENTION(S): The suitability was evaluated with the results of animal studies and the efficiency of HFF was investigated with the results of human IVF programs. MAIN OUTCOME MEASURE(S): Meiotic maturation of mouse oocytes, development of mouse embryos, morphological grades of human embryos, pregnancy rate in human IVF programs, and electrophoresis. RESULT(S): Human follicular fluid significantly stimulated meiotic resumption in mouse oocytes, even in the presence of meiotic inhibitors, and enhanced the developmental potential of mouse embryos in vitro. Compared with human fetal cord serum, human follicular fluid also improved the morphological grade of human embryos by reducing cytoplasmic fragmentation. In conventional IVF cycles of human IVF programs, use of HFF significantly increased the clinical PR (109/234 cycles, 46.5%; P < .05), compared with use of human fetal cord serum (14/52 cycles, 26.9%). However, in intracytoplasmic sperm injection cycles, there was no difference in PRs between use of HFF (38/85 cycles, 44.7%) and use of human fetal cord serum (7/17 cycles, 41.1%). When the protein compositions of human fetal cord serum and HFF were investigated by electrophoresis, a protein of 21 kD was detected specifically in HFF. CONCLUSION(S): Human follicular fluid is suitable for use as a protein supplement and is effective in increasing the pregnancy rate in human IVF programs.